9 International Vanadium Symposium Chemistry ... - Chimica UniPD [PDF]

9th International Vanadium Symposium Chemistry, Biological Chemistry & Toxicology

Book of Abstract

June 29th – July 2nd, 2014 Padova, Italy

Organizing Committee Giulia Licini (Chair), University of Padova, Padova, Italy Valeria Conte (Chair), University of Roma TorVergata, Rome, Italy Cristiano Zonta (Secretary), University of Padova, Padova, Italy Pierluca Galloni, University of Roma TorVergata, Rome, Italy Emanuele Amadio, University of Padova, Padova, Italy Elena Badetti, University of Padova, Padova, Italy Alessandro Bonetto, University of Padova, Padova, Italy Rosalia Di Lorenzo, University of Padova, Padova, Italy Claudia Miceli, University of Padova, Padova, Italy Federica Sabuzi, University of Padova, Padova, Italy

International Advisory Board Valeria Conte, Rome, Italy Mitchell D. Cohen, Tuxedo, NY, USA João Costa Pessoa, Lisbon, Portugal Debbie C. Crans, Fort Collins, CO, USA Toshikazu Hirao, Osaka, Japan Kan Kanamori, Toyama, Japan Tamas Kiss, Szeged, Hungary Kenneth Kustin, San Diego, CA, USA Hitoshi Michibata, Higashi-Hiroshima, Japan Craig McLauchlan, Normal, IL, USA (secretary) Vincent Pecoraro, Ann Arbor, MI, USA Dieter Rehder, Hamburg, Germany

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9th International Vanadium Symposium, Padova – 29th June - 2nd July 2014

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9th International Vanadium Symposium, Padova – 29th June - 2nd July 2014

The 9th International Vanadium Symposium is held under the auspices of:

Dipartimento Scienze Chimiche, University of Padova – Italy

Dipartimento di Scienze e Tecnologie Chimiche University of Roma TorVergata – Italy

Società Chimica Italiana – Sezione Veneto

and with the sponsorship of:

Gruppo Interdivisionale di Catalisi – Società Chimica Italiana

VPRA – Vanitec

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9th International Vanadium Symposium, Padova – 29th June - 2nd July 2014

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9th International Vanadium Symposium, Padova – 29th June - 2nd July 2014

History of Vanadium Symposia By Dieter Rehder The development of the understanding and recognition of the remarkable properties of vanadium compounds has stimulated the exploration of the chemistry and biochemistry of vanadium, its (potential) medicinal applications, and its deployment in new materials. Being at the same time consequence and drive for a steady progress in several areas, research into and applications of vanadium complexes range from therapeutics to catalysis, and from new materials to "green chemistry". The past two decades have witnessed an outburst of research into this field, as the several published books [1-6] and many reviews undoubtedly state. The interest in meetings centered on vanadium science can be traced back to 1986, when the very first specific meeting dedicated to vanadium chemistry, entitled "Role of Vanadium in Biology", was held within the Federation of American Societies for Experimental Biology Meeting. A synopsis from this symposium became included in the Federation proceedings [7]. In the second event of this kind, chemical aspects were emphasized. The meeting, entitled "Biochemistry of Vanadium", was held in 1993 on occasion of the 45th ACS Southeast Regional Meeting (Johnson City, Tennessee, USA). The third vanadium centered meeting followed in 1994 in Montreal (Canada), and embraced the important pharmacological scope. Contributions to this meeting, entitled "Vanadium: Biochemistry, Physiology, and Potential Use in Diabetes Therapy", were published in a special volume of Molecular and Cellular Biochemistry [8]. Three years later vanadium chemistry was given for the first time the prominence of a satellite session, at the 8th International Conference for Bioinorganic Chemistry - ICBIC 8 (Yokohama, Japan, 1997). That meeting was followed by another one in the same year entitled "Chemistry, Biochemistry, and Therapeutic Applications of Vanadium Compounds", held at the 5th North American Chemical Congress (in Cancun, Mexico, November 10-14, 1997). This symposium, with Alan S. Tracey and Debbie C. Crans as chairs, is considered to be the 1st International Vanadium Symposium - V1 Symposium. A volume within the ACS Symposium Series was published with contributions from this meeting [9]. The V1 Symposium initiated the tradition on these vanadium-focused theme meetings to be held every two years. The 2nd Symposium, on Biological Aspects of Vanadium, was held in Berlin, Germany, August 16-17, 1999, with Dieter Rehder and Valeria Conte as chairs. A special issue of the Journal of Inorganic Biochemistry (80(1-2), 2000) was published with contributions from this meeting. The V3 Symposium, 3rdInternational Symposium on the Chemistry and Biological Chemistry of Vanadium(which remained the official title of the symposium for the V3-V7 symposia) was held in Osaka, Japan, November 26-29, 2001, with Toshikazu Hirao as chair. A special volume of Coordination Chemistry Reviews (237(1-2), 2003) was published with contributions from this meeting. The V4 Symposium was held inSzeged, Hungary, September 3-5, 2004, with Tamás Kiss as chair. The journal Pure and Applied Chemistry (77(9), 2005) published an issue entirely dedicated to this meeting. St. Francisco (California, USA) directed the V5 Symposium, held within the 232nd ACS Fall Meeting in September 10-14, 2006, with Debbie Crans as chair, and João Costa Pessoa and Ken Kustin as co-chairs. The meeting is documented in 5

9th International Vanadium Symposium, Padova – 29th June - 2nd July 2014

a special volume (vol. 974) of the ACS Symposium Series. The V6 Symposium, chaired by João Costa Pessoa, took place in Lisbon, Portugal, July 17-19, 2008. Toyama, Japan, has been the venue for the V7 Symposium (chairs: Hitoshi Michibate, Kan Kanamori; co-chair: Toshikazu Hirao), October 6-9, 2010. Selected contributions to this meeting are compiled in vol. 255 (issues 19-20, 2011) of Coordination Chemistry Reviews. At the V8 Symposium the title of the symposium became adapted to developments directed towards the role of vanadium in material sciences and toxicology. The 8th International Vanadium Symposium on the Chemistry, Biological Chemistry, and Toxicology, chaired by Mitch Cohen, Andrew Ghio and Craig C. McLauchlan, was held in Arlington (Virginia, USA), August 15-18, 2012. Selected contributions are published in special issues of Dalton Transactions and Journal of Immunotoxicology Starting with the 4th meeting in 2004, a Vanadis Award has been bestowed to a distinguished chemist in the field of vanadium chemistry. Present awardees are Debbie C. Crans (2004), Dieter Rehder (2006), Toshikazu Hirao (2008), Vincent L. Pecoraro (2010) and Israel E. Wachs (2012). The award committee is essentially composed of former chairs of vanadium symposia. References [1] Vanadium in Biological Systems. Physiology and Biochemistry. Chasteen, N.D., Ed.; Kluwer Academic Publishers: Dordrecht, Netherlands, 1990. [2] Vanadium in the Environment. In: Adv. Environ. Science Technol. Nriagu, J.O., Ed.; John Wiley & Sons, New York, 1998; vol. 23, parts 1 and 2. [3] Vanadium and Its Role in Life. In: Metal Ions in Biological Systems. Sigel, H.; Sigel, A., Eds.; Marcel Dekker, New York, 1995; vol. 31. [4] Tracey, A. S.; Willsky, G. R.; Takeuschi, E. S.: Vanadium. Chemistry, Biochemistry, Pharmacology and Practical Applications. CRC Press, Taylor & Francis Group, Boca Raton, USA, 2007. [5] Vanadium Biochemistry. M. Aureliano, Ed.; Research SignPost, Kerala, India, 2007. [6] Rehder, D.: Bioinorganic Vanadium Chemistry, A Wiley Textbook Series, Wiley, Chichester, England, 2008. [7] Nechay, B. R.; Nanninga, L. B.; Nechay, P. S. E.; Post, R. L.; Grantham, J. J.; Macara, I. G.; Kubena, L. Fl.; Philips, T. D.; Nielsen, F. H. FASEB Fed. Proc. 1986, 45, 123-132. [8] Vanadium Compounds: Biochemical and Therapeutic Applications; Srivastava, A. K.; Chiasson, J.-L., Eds.; Focused issue in Mol. Cell. Biochem. 1995, 153. [9] Vanadium Compounds. Chemistry, Biochemistry, and Therapeutic Applications; A.S. Tracey, D.C. Crans, Eds.; ACS Symposium Series Vol. 711; Oxford University Press: Washington, DC, USA, 1998.

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Vanadis Award The Vanadis Award is presented to a researcher in the area of Vanadium Science on the basis of contributions to vanadium chemistry, biochemistry, biology or pharmaceutical science or combinations thereof, and will be given to those having displayed innovative research and have had a documented impact on the direction of the field.

The 6th Vanadis Award winner is João Costa Pessoa Instituto Superior Técnico, Universidade de Lisboa, Portugal João Costa Pessoa received his 5-year undergraduate education (1974) at Instituto Superior Técnico (IST), Universidade Técnica de Lisboa (UTL), and started his university career at IST as Assistant in 1974. He continued his graduate education at the Universidade Nova de Lisboa, under the supervision of Professor Luís Vilas Boas. As Assistant Professor, he developed studies of systems containing VIVO2+ and small peptides [namely the binding of the amide nitrogen to V(IV)], sugars, hydroxy acids, Schiff bases and other ligands of biological relevance, and structural characterization of the species formed. As Associate Professor (1995-2011) and Full Professor (2011-present) he continued similar studies also with systems of copper, nickel and zinc compounds, and the research evolved into modeling of complex aspects of vanadium biology such as interactions with biological macromolecules. Namely, JCP started studying the speciation of metal ions in blood serum, particularly to understand the transport of vanadium, copper and ruthenium therapeutic drugs in blood and their uptake by cells, and the study of interactions of metal ions with high molecular weight biomolecules. Besides the global understanding of the transport of the metal compounds in blood, relevant findings were e.g. the strong binding of VIII and VIV to transferrin (hTF) and the binding of VV to holo-hTF. More recently he has been applying efforts to the design of therapeutic agents for the treatment of diabetes, cancer, tuberculosis and parasitic diseases caused by protozoans. Since ca. 2006 he also became involved in the use of metal complexes as homogeneous and heterogeneous catalytic systems, particularly for asymmetric synthesis of organic compounds and to improve activity, recyclability and sustainability of the systems developed, as well as to understand mechanisms of reactions. In this field contributions to the heterogenization of complexes to be used as catalysts, using or not linkers, 7

9th International Vanadium Symposium, Padova – 29th June - 2nd July 2014

and identification of vanadium species formed as intermediates, may be highlighted. Concerning University Management Contributions, having been Vice-President of the Scientific Council of IST-UTL (1999-2001) and being Director of Centro de Química Estrutural (IST-UL, 2009-present) may be highlighted.

Vanadis Award Committee Valeria Conte (Italy) João Costa Pessoa (Portugal) Debbie Crans (USA) Toshikazu Hirao (Japan) Kan Kanamori (Japan) Tamas Kiss (Hungary) Hitoshi Michibata (Japan) Craig McLauchlan (USA) Vincent Pecoraro (USA) Dieter Rehder (chair; Germany) Alan Tracey (Canada) Israel Wachs (USA)

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Short Scientific Program

Sun., June 29th

Mon., June 30th

Tue., July 1st 8,30

9,00 9.15 10.00

10.00 10.30 10.30 11.00 11.00 11.45 11.45 12.15

Wed., July 2nd

PL 2 - M. Bühl

9.15

Opening remarks PL 1 - A. Ghio

O1-O2 Coffee Break O3-O5

IL 1 - T. Ueki

9.15 10.00

O14-O16

10.00 10.30 10.30 11.00 11.00 12.00

IL 4 - J. Krzystek

12.00 12.30

IL 5 - R. Neuman

Coffee Break O17-O20

9.00 10.00

Vanadis Award João Costa Pessoa O27

10.10 10.30 10.30 Coffee Break 11.00 11.00 PL 3 - B.-J. 12.05 Uang 12.05 12.35

12.30 Lunch and Poster 12.30 Lunch and Poster 12.35 14.30 14.45 12.45 Session Session

O28 IL 8 - V. Pecoraro Closing Remarks

(IAB meeting) 14.30 15.00

17.00 19.30

15.00 O6-O9 16.00 16.00 Registration Coffee Break Caffè Pedrocchi 16.30 16.30 IL 3 - D. Gambino 17.00 17.00 18.00 18.00 19.00

19.30

IL 2 - C. Leblanc

14.45 15.15

IL 6 - Fabrizio Cavani

15.15 16.05 16.10 16.30 16.30 17.30

O21-O23

14.30 Padova 18.00 Walking Tour

Coffee Break L. Pettersson Memorial O24-O26

17.30 IL 7 - A. Pombeiro 18.00 19.30 Bus Leaving

O10-O13 Poster Session

20.15 Social Dinner 'La

Welcome Reception Caffè Pedrocchi

Montanella' Arquà Petrarca

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9th International Vanadium Symposium, Padova – 29th June - 2nd July 2014

Scientific Program Sunday, June 29th – Caffè Pedrocchi

17.00

19.30 Registration

19.30

21.00 Welcome Reception

Monday, June 30th – Centro Culturale Altinate/San Gaetano

9.00

9.15

Opening: Valeria Conte, Giulia Licini Chair Debbie C. Crans

9.15

10.00 PL 1 Andrew Ghio - US Environmental Protection Agency, Chapel Hill, The biological effect of vanadium and its interactions with iron

10.00

10.15

O1 Maja A. Larsson - University of Agricultural Sciences, Department of Soil and Environment, Uppsala, Sweden, Vanadium sorption in soils

10.15

10.30 O2 Rodger Battersby - Vanadium Consortium/ EBCR Consulting GmbH, Hannover, Germany, Human Health Hazards and the Lack thereof of Vanadium Substances Differing in Solubility and Valence

10.30

11.00 Coffee Break Chair Mitchell D. Cohen

11.00

11.15

O3 Amit Kumar Tyagi - Center for Nano & Material Science, Jain University Bangalore, Bangalore, India, Anti-amoebic Activity of Vanadium Complexes

11.15

11.30

O4 Judith A. MacGregor - Toxicology Consulting Services, Bonita Springs, USA, Investigations on the Human Relevance of Vanadium Pentoxide-induced Mouse Lung Tumors

11.30

11.45

O5 Craig McLauchlan - Illinois State University, Normal, USA, Vanadium in Phosphatases: Using a “Magnifying Glass” for Viewing Inhibitor Binding at the Active Site

11.45

12.15

IL 1 Tatsuya Ueki - Hiroshima University, Onomichi, Japan, Vanadium Accumulation in Ascidians: An Overview as a System

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9th International Vanadium Symposium, Padova – 29th June - 2nd July 2014

12.30

14.30 Free Lunch + Poster Session Chair Tamas Kiss

14.30

15.00 IL 2 Catherin Leblanc - CNRS-UPMC, UMR 8227, Integrative Biology of Marine Models, Roscoff, France, Structure and evolution of vanadium haloperoxidases

15.00

15.20 O6 Ron Wever – University of Amsterdam, The Netherlands, The role of vanadium chloroperoxidases in the formation of chloroform and the impact on the environment

15.20

15.35 O7 Martinus C. Feiters - Radboud University Nijmegen, Institute for Molecules and Materials, Nijmegen, The Netherlands, X-Ray Absorption Spectroscopic Studies of Vanadium-containing Haloperoxidases

15.35

15.45 O8 Federica Sabuzi – Università TorVergata, Roma, Italy, V-catalyzed bromination of thymol: enzymatic vs. chemical catalysis.

15.45

16.00 O9 Matthias Amberg - TU Kaiserslautern, Kaiserslautern, Germany, cis2,6-Bis-(methanolate)-piperidine oxovanadium(V) complexes as catalysts for chemoselective oxidation of alkenols by tert-butyl hydroperoxide

16.00

16.30 Coffee Break Chair Craig McLauchlan

16.30

17.00 IL 3 Dinorah Gambino - Universidad de la República, Montevideo, Uruguay, Rational Design of Prospective Antiparasitic Oxidovanadium(IV) Compounds based on Quantitative Structure-Activity Relationships

17.00

17.15 O10 Seiichi Matsugo - Kanazawa University, Kanazawa, Japan Mechanistic Approach of the Insulin Signaling Enhancement by Peroxidovanadium Complexes

17.15

17.30 O11 Isabel Correia - Universidade de Lisboa, Portugal, Vanadium(IV and V) hydroxyquinoline-containing complexes as potential anti-tumor and antimycobacterial agents

17.30

17.45 O12 Xiao Xu - UMR 8580 du CNRS, Ecole Centrale Paris, ChâtenayMalabry, France, Experimental Charge Density Study of a Fluorescent Polyoxovanadate-Based Charge Transfer Hybrid

17.45

18.00 O13 Winfried Plass - Friedrich-Schiller-University, Jena, Germany, Chiral Vanadium(V) Complexes with Schiff-Base Ligands: Characterization of Diastereomers in Solid State and Solution

18.00

19.00 Poster Session

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9th International Vanadium Symposium, Padova – 29th June - 2nd July 2014

Tuesday, July 1st – Centro Culturale Altinate/San Gaetano Chair Joao Costa Pessoa 8.30

9.15

PL 2: Michael Bühl - University of St Andrews, St Andrews, UK, Modeling 51V NMR parameters from first principles

9.15

9.35

O14 Anastasios D. Keramidas - University of Cyprus, Nicosia, Cyprus, Electron transfer in redox binary Hydroquinone/p-Semiquinone -V(III/IV/V) systems, structure and reactivity

9.35

9.45

O15 Sergey Nagorny - Istituto Nazionale di Fisica Nucleare - Laboratori Nazionali del Gran Sasso, Assergi, Italy, Characterization of biological origin Vanadium for nuclear physics applications Chair Len Levy

9.45

10.00 O16: Kavosh Majlesi - Shanxi University, Tehran, Iran, Thermodynamic Study on the Complexation of Dioxovanadium (V) with GLDA and D-(-)-Quinic Acid in Aqueous Solutions of Ionic Liquid

10.00

10.30 IL 4 Jurek Krzystek - Florida State University, Tallahassee, USA, HighFrequency and -Field EPR Spectroscopy of Vanadium(III): from Curiosity to Practicality

10.30

11.00 Coffee Break Chair Israel Wachs

11.00

11.15 O17 Mannar R. Maurya - Institute of Technology Roorkee, Roorkee, India, Synthesis, Characterization and Reactivity of Oxidovanadium(IV) and Dioxidovanadium(V) Complexes and their Catalytic Activity

11.15

11.30 O18 Toshiyuki Moriuchi - Osaka University, Osaka, Japan, Structural Characterization of Vanadium(V) Hydrazido Complexes

11.30

11.45 O19 Lukáš Krivosudský - Comenius University, Bratislava, Slovakia, Mirror symmetry breaking crystallization of M[VO2(N‒salicyliden‒isoleucinato)] ?

11.45

12.00 O20 Emanuele Amadio –Università degli Studi di Padova, Padova, Italy, Vanadium catalyzed aerobic oxidative cleavage of lignin model substrates

12.00

12.30 IL 5 Ronny Neuman - Weizmann Institute of Science, Rehovot, Israel, A Vanadium Substituted Polyoxometalate, H5PV2Mo10O40 as a Catalyst for Electron Transfer-Oxygen Transfer Oxidations. A Unique Compound for Unique Transformations

12.30

14.45 Free Lunch + Poster Session (IAB Meeting) 12

9th International Vanadium Symposium, Padova – 29th June - 2nd July 2014

Chair Kan Kanamori 14.45

15.15 IL 6 Fabrizio Cavani – Università di Bologna, Bologna, Italy, The Role of Vanadium in Mixed Oxides Catalysts for Gas-phase One-pot Reactions

15.15

15.35 O21 Israel E. Wachs - Lehigh University, Bethlehem, PA, USA, Comparison of co-precipitated and impregnated supported V2O5-WO3/TiO2 catalysts for selective reduction of NO with NH3

15.35

15.50 O22 Dimitrios Manganas - Max Planck Institute for Chimcal Energy Comversion, Mülheim an der Ruhr, Germany Towards a Spectroscopic Understanding of Silica Supported Vanadia-based Catalysts

15.50

16.10

16.05 O23 Luca Artiglia - Unversità deli Studi di Padova, Padova, Italy, Atomic Structure and Special Reactivity Toward Alcohol Oxidation of Vanadia Nanoclusters on TiO2(110) 16.30 Coffee Break Chair Vincent Pecoraro

Dieter Rehder - University of Hamburg, Hamburg, Germany, 16.30

16.45 Commemorating Lage Pettersson

O24 Yoshihito Hayashi - Kanazawa University, Kanazawa, Japan, 16.45

Coordination Chemistry of Macrocyclic Polyoxovanadate Ligands for Lanthanide 17.00 Complexes

17.00

17.15 O25 Tamas Jakusch - University of Szeged, Szeged, Hungary, Vanadium(V/IV) complexes of thiosemicarbazones and semicarbazones

17.15

17.30 O26 Nadia Marino - Università della Calabria, Rende, Italy, Vanadium-based molecular assemblies as efficient catalytic systems for relevant oxidation processes

17.30

18.00 IL 7Armando Pombeiro - Instituto Superior Tecnico, Lisboa, Portugal, Vanadium Catalysts in Alkane Partial Oxidation

20.15

Social Dinner Ristorante La Montanella, Arquà Petrarca, PD

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9th International Vanadium Symposium, Padova – 29th June - 2nd July 2014

Wednesday, July 2nd – Archivio Antico, palazzo del Bo 9.00

10.00 Dieter Rehder, Institut für Anorganische und Angewandte Chemie, Hamburg, introducing Vanadis Award Lecture

João da Costa Pessoa - Instituto Superior Tecnico, Lisboa, Portugal, My Way Through Vanadium Chemistry Chair Dieter Rehder 10.10

10.30

O27 Debbie Crans - Colorado State University, Fort Collins, USA, Correlating Compound Physical Properties with Anti-Diabetic Effects; Dipicolinatooxovanadium(V) Substituted Compounds

10.30

11.00 Coffee Break Chair Toshikazu Hirao

11.00

11.45 PL3 Biing-Jiun Uang - National Tsing Hua University, Hsinchu, Taiwan, Oxovanadium Species Mediated C-C Bond Formation

11.45

12.05 O28 Athanasios S.Salifoglu - Aristotle University of Thessaloniki, Thessaloniki, Greece, Vanadium metallodrugs: from the design to the anticancer biology

12.05

12.35 IL 8 Vincent Pecoraro - University of Michigan, Ann-Arbor, USA, Initial Steps for the Development of de novo designed Vanadium Haloperoxidases

12.35

12.45 Closing of the 9th International Vanadium Symposium

13.00

14.30 Free Lunch

14.30

18.00 Walking tour “Classic Padova Tour”

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9th International Vanadium Symposium, Padova – 29th June - 2nd July 2014

Poster Communications P1

P. Antal – Department of Inorganic Chemistry, Faculty of Natural Sciences, Comenius University, Bratislava, Slovak Republic – New mandelato complexes of vanadium(V).

P2

E. Badetti – Dipartimento di Scienze Chimiche, Università di Padova, Padova, Italy – Haloperoxidation Reactivity of V(V), Mo(VI) and W(VI) Amine Trisphenolate Complexes.

P3

C. Bandinelli – Dipartimento di Chimica Industriale “Toso Montanari”, ALMA MATER STUDIORUM Università di Bologna, Bologna, Italy – One-pot Glycerol Oxidehydration to Acrylic Acid on Hexagonal-Tungsten-Bronze-Derived Structures as Multifunctional Catalysts.

P4

I. Boukhobza – Department of Interdisciplinary Studies, Zayed University, Dubai ,UAE – Separation of Vanadium Compounds by HPLC; Reverse phase, Normal phase, Ion pair, Cation and Anion Exchange matrices and vanadium speciation

P5

N. Butenko – Universidade do Algarve, Departamento de Química e Farmácia, Faculdade de Ciência e Tecnologia, Campus de Gambelas, Faro, Portugal – VO(acac)2-phosphate Complex as Species Responsible for the Efficient Nuclease Activity of VIVO(acac)2.

P6

D. C. Crans – Department of Chemistry, Colorado State University, Fort Collins, USA – How Important is the Trigonal Bipyramidal Geometry for Phosphatase Inhibitors?

P7

A. Dieronitou – University of Cyprus, Department of Chemistry, Nicosia, Cyprus – Investigation of vanadium (IV) or (V) compounds towards the formation of reactive oxygen species in biomimetic media.

P8

R. Di Lorenzo – Dipartimento di Scienze Chimiche, Università di Padova, Padova, Italy – Towards Water Soluble Vanadium(V) Amine Triphenolate Catalysts.

P9

M. Dönges – TU Kaiserslautern , Kaiserslautern, Germany – Diastereocontrol by Alkene Configuration in Vanadium(V)-catalyzed Oxidative 4-Pentenol Cyclization.

P10 C. Drouza – Cyprus University of Technology, Department of Agriculture Sciences, Biotechnology and Food Science, Lemesos, Cyprus – Synthesis and characterization of amphiphilic V(IV/V) complexes as paramagnetic probes for applications on edible oils.

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9th International Vanadium Symposium, Padova – 29th June - 2nd July 2014

P11 S.B. Etcheverry – Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina – Anticancer drug development. Effects of a complex of oxidovanadium(IV) with silibinin in osteoblast cell lines. Relationship with the inhibition of topoisomerase IB.

P12 P. Galloni – Department of Chemical Sciences and Technology, University of Roma Tor Vergata, Roma, Italy – Electrochemical fingerprints of vanadyl complexes.

P13 E. González Vergara – Benemérita Universidad Autónoma de Puebla, México – Synthesis, characterization and 3D supramolecular interactions of

metforminium decavanadate, (H2Met)3(V10O28)·8H2O.

P14 M. de F. Guedes Da Silva – Centro de Química Estrutural, Complexo I, Instituto Superior Técnico, Universidade de Lisboa, Av. Lisboa, Portugal – Oxidovanadium Complexes as Homogeneous and Supported Catalysts for the Microwave Assisted Oxidation of Alcohols.

P15 R.D. Holtz – Solid State Chemistry Laboratory, Institute of Chemistry, State University of Campinas – UNICAMP, Campinas-SP, Brazil – The promising use of nanostructured silver vanadates as antibacterial additive to coatings used in places with risks of bacterial contamination.

P16 L. Lu – Institute of Molecular Science, Shanxi University, Taiyuan, P.R. China – The influence of vanadium complexes on cellular phosphorylation.

P17 M. R. Maurya – Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee, India – Synthesis, Characterization and Reactivity of Oxidovanadium(IV) and Dioxidovanadium(V) Complexes and their Catalytic Activity.

P18 C. C. McLauchlan – Department of Chemistry, Illinois State University, Normal, IL, USA – Inhibition of Neutral Sphingomyelinase by Bisphosphonate and Vanadium-Bisphosphonate Compounds.

P19 J. Olopade – Department of Veterinary Anatomy, University of Ibadan, Nigeria – The Deterioration Seen in Myelin Related Morphophysiology in Vanadium Exposed Rats is Partially Protected by Concurrent Iron Deficiency.

P20 M. Radlow – Technische Universität Kaiserslautern, Kaiserslautern, Germany – Structure and Reactivity of the Second Bromoperoxidase from Ascophyllum nodosum

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9th International Vanadium Symposium, Padova – 29th June - 2nd July 2014

P21 A.R. Rezvani – Department of Chemistry, University of Sistan and Baluchestan, Zahedan, Iran – Vanadium complexes of novel thiourea derivatives; structural and biological investigations as potential antimicrobial agents.

P22 A. Salifoglou – Department of Chemical Engineering, School of Engineering, Aristotle University of Thessaloniki, Thessaloniki, Greece – Insight into vanadium anticancer action in metastastic processes.

P23 N. Samart – School of Chemistry, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima 30000 Thailand – Decavanadate interaction with interfaces

P24 A. Ścibior – Laboratory of Oxidative Stress, Center for Interdisciplinary Research, The John Paul II Catholic University of Lublin, Poland – The effect of vanadium and magnesium administration on rat femoral bone micromorphology.

P25 M. L. Tarlton – Illinois State University, Normal, Illinois, USA – Synthesis, Characterization, and Oxidative Catalytic Activity of Phosph(on/in)ate Bridged V(IV/IV) Dimers: New Routes to Industrially Important Quinones Through Dimensional Reduction.

P26 S. Treviño Mora – Benemérita Universidad Autónoma de Puebla, México – Biological Studies of Metforminium Decavanadate, (H2Met)3(V10O28)·8H2O.

P27 H. Vilter – Trier University of Applied Sciences, Trier, Germany – Vanadiumdependent haloperoxidase from Ascophyllum nodosum Touchable 3D-models – from x-chrystallography to 3D-print.

P28

A. Voigt – EBRC Consulting GmbH, Hannover,Germany – Developing Environmental Quality Standards for Vanadium in Soil, Sediments and Freshwater.

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9th International Vanadium Symposium, Padova – 29th June - 2nd July 2014

PLENARY LECTURES

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9th International Vanadium Symposium, Padova – 29th June - 2nd July 2014

PL1 The biological effect of vanadium and its interactions with iron A. Ghio,a J. Soukup,a L. Dailey,a M. Cohenb a

Environmental Public Health Division, US Environmental Protection Agency, Chapel Hill, North Carolina b Department of Environmental Medicine, New York University School of Medicine, Tuxedo, New York, USA e-mail: [email protected]

Vanadium compounds of dissimilar valence and composition can initiate inflammation and fibrosis in human tissues. The underlying mechanism for the biological effect following vanadium exposure is incompletely understood. We tested the postulate that exposure to vanadium compounds decreases host cell and mitochondrial iron concentrations which mediates an oxidant generation culminating in a biological effect. In vitro exposure of human bronchial epithelial (HBE) cells to vanadium (IV) sulfate oxide (0 to 50 µM) for 1 to 4 hr resulted in elevations of intracellular vanadium. Cell non-heme iron concentrations were diminished at the same time points. Cell incubation with vanadium was associated with elevated levels of RNA for the iron importer divalent metal transporter 1 (DMT1) reflecting a deficiency of iron. If iron were made available to the HBE cells either at the same time of or immediately following the VOSO4 exposure, concentrations of intracellular non-heme iron were increased along with the expression of the storage protein ferritin at 24 hr. Following exposure to VOSO4, mitochondrial vanadium concentrations were increased while non-heme iron concentrations in the organelle were decreased. Diminished mitochondrial 57Fe concentrations following vanadium exposure confirmed the effect of VOSO4. Pre-incubation of cells with excess ferric ammonium citrate increased cell, nuclear, and mitochondrial metal concentrations and prevented significant iron loss from mitochondria following vanadium exposure. Cell oxidant generation increased after vanadium incubation but pre-treatment with iron diminished this generation of reactive oxygen species. Vanadium exposure increased RNA for and protein expression of pro-inflammatory cytokines (interleukin-8 and -6). These changes in indices of biological effect were either diminished or totally inhibited by cell pretreatment with iron. We conclude that an initiating event in the response to vanadium compounds is a reduction in cell and mitochondrial iron. The resultant oxidative stress and biological response after vanadium exposure are either diminished or inhibited by increasing the cell iron concentration. Acknowledgements: This work was funded by the US Environmental Protection Agency

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PL2 Modeling 51V NMR parameters from first principles M. Bühla a

School of Chemistry and Centre of Magnetic Resonance, University of St Andrews, United Kingdom e-mail: [email protected]

An overview of density-functional theory (DFT) based computations of 51V NMR chemical shift and electric field gradient (EFG) tensors will be given, calling special attention to medium effects in a condensed phase. The dynamic ensemble of a liquid or an aqueous solution can be modeled through molecular dynamics simulations, notably in the Car-Parrinello variant (CPMD).1,2 Longrange electrostatic effects that can become important in static, solid-state NMR can be included by way of a hybrid quantum-mechanical/molecular-mechanical (QM/MM) approach, as for instance applied to vanadium-containing haloperoxidases3 and to periodic molecular crystals in a finite cluster description.2 A new way to perform geometry optimisations for such molecular crystals is described, and a showcase application to a vanadium catechol complex highlighted (see Chart below).4

Chart: Vanadium(V) catechol complex studied in reference 4; the 51V EFG tensor in the solid state is very sensitive to both short-range (H-bonds) and long-range intermolecular interactions. References 1. Bühl, M.; Parrinello, M. Chem. Eur. J. 2001, 7, 4487-4494. 2. Bjornsson, R.; Früchtl, H.; Bühl, M. Phys. Chem. Chem. Phys. 2011, 13, 619–627. 3. (a) Waller, M. P.; Bühl, M.; Geethalakshmi, K. R.; Wang, D.; Thiel, W. Chem. Eur. J. 2007, 13, 4723-4732; (b) Geethalakshmi, K. R.; Waller, M. P.; Thiel, W.; Bühl, M. J. Phys. Chem. B 2009, 113, 4456-4465. 4. Bjornsson, R.; Bühl, M. J. Chem. Theory Comput. 2012, 8, 498-508.

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PL3 Oxovanadium Species Mediated C-C Bond Formation B.-J. Uang Department of Chemistry, National Tsing Hua University e-mail: [email protected]

The design of novel reactions that proceed with high atom economy and enable multiple transformations through a shorter reaction sequence is an integral part of the modern organic synthesis. Vanadium complexes exhibit a rich redox chemistry providing potential tools in the organic synthesis. Biaryl moiety is the core structural component of many important natural products. Oxidative biaryl coupling of phenols has received considerable attention owing both to its utility as a synthetic reaction and its proposed involvement in the biosynthesis of many natural products containing biaryl segment. Documented methods for the oxidative coupling of 2-naphthols made use of various transitional metal species as oxidants both in stoichiometric and catalytic amounts. However, most of these methods have their own limitations either involving tedious procedures or requiring harsh reaction conditions. It is found that oxovanadium species are able to achieve the oxidative coupling of aryl alcohols in high yields. The asymmetric version of chiral biaryls could also be achieved. The Mannich reaction is an important carbon-carbon bond formation reaction widely used in the synthesis of secondary and tertiary amine derivatives and applied as a key step in the synthesis of many bioactive molecules and complex natural products. This reaction basically involves the addition of a carbon nucleophile to an iminium ion, resulting in a secondary or tertiary amine derivative depending on the nature of the substrate. We have developed vanadium-catalyzed reaction into an expedient general method for the in situ generation of iminium ions from tertiary amine N-oxides for their subsequent application in a modified Mannich-type reaction. A few more oxovanadium species mediated C-C bond formation will also be presented. Acknowledgements: This work was supported by National Science Council, Republic of China (Taiwan).

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6th VANADIS AWARD LECTURE

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VA Interaction of therapeutic vanadium complexes with serum proteins J. Costa Pessoaa, I. Correia,a S. Roy,a E. Garribba,b M.F.A. Santos,c T. Santos-Silvac a

Centro Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal b Dipartimento di Chimica e Farmacia, and Centro Interdisciplinare per lo Sviluppo della Ricerca Biotecnologica e per lo Studio della Biodiversità della Sardegna, Università di Sassari, Via Vienna 2, I-07100 Sassari, Italy. c REQUIMTE-CQFB, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal. e-mail: [email protected]

For the prospective therapeutic use of vanadium compounds the understanding of their transport and delivery to cells are crucial issues, and strong evidence has been given indicating that most of the vanadium in the serum is bound to transferrin (hTF) 1. In this communication we discuss the binding of VIVO-species to hTF. Not much attention has been given to the possibility of transport of vanadium in the oxidation states +3 or +5. This report also focus on results addressing the binding of VV- and VIII-species to transferrin and the relevance of this binding for the uptake of vanadium by cells. It was demonstrated that when vanadium is administered in the form of a complex, e.g. VIVO(carrier)2, where carrier is an organic compound acting as a bidentate or tridentate ligand, two types of VIVO-carrier-hTF binding have been proposed: one with VIV at the Fe-binding site, the other at surface imidazole or carboxylate groups 1,2. The binding of VIVO(carrier)2 species to surface His or Asp is possible and we report here its confirmation by a x-ray diffraction study of VIVO(pic)2-HEWL complexes (HEWL = Hen egg white lysozyme). However, the relevance of this type of binding to the transport and delivery of VIV to cells is not known, being an issue also discussed in this communication. Structural representation of VIVO(pic)2-Asp52 adduct of HEWL. Vanadium presents a distorted octahedral geometry with two bidentate picolinate ligands and an Ooxido donor. This is the first VIVOprotein adduct characterized by X-ray diffraction; the non-usual VIV-O distance obtained is discussed.

References a) Costa Pessoa, J.; Tomaz, I. Curr. Med. Chem. 2010, 17, 3701-3738. b) Kiss, T.; Jakusch, T.; Hollender, D.; Dörnyei, A.; Enyedy, E.A.; Costa Pessoa, J.; Sakurai, H.; Sanz-Medel, A. Coord. Chem. Rev. 2008, 252, 11531162. a) Sanna, D.; Micera, G.; Garribba, E. Inorg. Chem. 2010, 49, 174-187. b) Sanna, D.; Buglyó, P.; Bíró, L.; Micera, G.; Garribba, E. J. Inorg. Biochem. 2012, 115, 87-99.. Acknowledgements: Fundação para a Ciência e Tecnologia (FCT), PEst-OE/QUI/UI0100/2013 and PEstC/EQB/LA0006/2011.

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INVITED LECTURES

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IL 1 Vanadium Accumulation in Ascidians: An Overview as a System T. Uekia,b, N. Yamaguchia,c, Romaidib,d Y. Isagob, H. Tanahashib a

Marine Biological Laboratory, and b Molecular Physiology Laboratory, Graduate School of Science, Hiroshima University, 2445 Mukaishima, Hiroshima 722-0073, Japan. c Technology Center, Hiroshima University, 1-1-1 Kagamiyama, Hiroshima 739-8524, Japan. d Biology Department, Science and technology faculty, State Islamic University of Malang, Jl. Gajayana No. 50, Malang 65144, Indonesia. e-mail: [email protected]

Ascidians are well known to accumulate extremely high levels of vanadium in their blood cells. The concentration of vanadium is determined in each species, and the highest one reaches 350 mM, which corresponds to 107 times that of sea water. How and why ascidians accumulate vanadium at such an extremely high levels? To address these questions, our research group has been trying to identify genes and proteins responsible for the accumulation and reduction of vanadium in vanadocytes, one type of blood cells, as well as the process of vanadium transport from sea water to blood cells through the branchial sac, intestine and blood plasma. Here, we would like to overview the accumulation steps as a system, especially related to concentration and chemical species of vanadium at each step, as were experimentally determined in a vanadium-rich ascidian Ascidia sydneiensis samea (Table 1)1. Comprehensive analysis on each organ has already revealed several categories of protein families, such as vanadium-binding proteins2 and vanadium transporters3. We would like to discuss possible participation of proteins at each step from biochemical viewpoint. Table 1. Vanadium in sea water and organs in Ascidia sydneiensis samea location/tissue

vanadium concentration

major vanadium species

sea water

35 nM

V(V)

branchial sac intestinal content intestine blood plasma blood cells cytoplasm vacuole

1.4 mM 0.4 mM 1.8 mM 50 µM 38 mM low high

n.d. n.d. n.d. n.d. – V(V) ---> V(IV) V(III) ?

reference Cole et al., 1983; Collier, 1984 Michibata et al. 1986 this study this study Michibata et al. 1986 Ueki et al. 2009 – Ueki et al. 2002

References 1. Cole. P.C. et al. Anal. Chim. Acta 1983, 153, 61-67. Collier, R.W. Nature 1984, 309, 441-442. Michibata et al. Biol. Bull. 1986, 171, 672-681. Ueki, T. et al. Zool. Sci. 2002, 19, 1001-1008. Ueki, T. et al. Biochim. Biophys. Acta 2009, 1790, 1295-1300. 2. Kawakami, N. et al. Biochim. Biophys. Acta 2009, 1794, 674-679. Kitayama, H. et al. Dalton Trans. 2013, 42, 11924-11925. Yamamoto, S. et al. Inorg. Chim. Acta 2014, in press. 3. Ueki, T. et al., Biochim. Biophys. Acta 2011, 1810, 457-464. Acknowledgements: This work was supported by Grants-in-Aid from the Ministry of Education, Culture, Sports, Science and Technology, Japan (Nos. 22224011, 25120508 and 25440170) and an Environmental Research Grant from the Nippon Life Insurance Foundation (2012).

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IL 2 Structure nd evolution of vanadium haloperoxidases J.-B. Fourniera,b, L. Delagea,b, P. Potina,b, G. Michela,b, P. L. Solaric, M. Feitersd, M. Czjzeka,b, C. Leblanca,b a

Sorbonne Universités, UPMC Univ Paris 06, UMR 8227, Integrative Biology of Marine Models, , Roscoff, France. b CNRS, UMR 8227, Integrative Biology of Marine Models, Roscoff, France. c MARS, Synchrotron SOLEIL, Gif-sur-Yvette, France. d Dept. Organic Chemistry, Inst. for Molecules and Materials, Radboud University, Nijmegen, The Netherlands. e-mail: [email protected]

In marine environment, vanadium-dependent haloperoxidases (VHPO) are likely to play a key role in the biogenic production of organo-halogens. These enzymes contain vanadate as a prosthetic group, and catalyze, in the presence of hydrogen peroxide, the oxidation of halide ions (Cl-, Br- or I-). They are classified according to the most electronegative halide that they can oxidize (1). Since the first discovery of a vanadium bromoperoxidase in the brown alga Ascophyllum nodosum thirty years ago (2), structural and mechanistic studies were mainly focused on two types of VHPO, chloro- and bromoperoxidases (2-4). A novel vanadium-dependent iodoperoxidase, specific for iodide oxidation, was recently characterized in a marine bacterium. In order to understand the molecular bases of halide specificity, 3D protein structure comparisons and sitedirected mutagenesis approaches have been conducted to identify targeted residues, involved in catalytic and specificity mechanisms. In this context, vanadium K-edge X-ray absorption spectroscopy was shown to give further important clues to understand the fine changes of V coordination into the active site of native, mutants and reactive intermediate forms of VHPO. Altogether, the combination of functional and structural data, at different resolution scales, shed a new light on the evolution of halide specificity among vanadium haloperoxidase family. References 1. Fournier J.-B., Leblanc C. (2013). In Outstanding Marine Molecules and New Trends in Analytical Methods (La Barre S. and Kornprobst J.-M., eds), Wiley, in press. 2. Vilter, H. Le Jol Bot. Mar. 1983, 26 (9): 429-435. 3. Messerschmidt A, Wever R. Proc Natl Acad Sci U S A. 1996, 93 (1):392-6 4. Weyand M, Hecht H, Kiess M, Liaud M, Vilter H, Schomburg D. J Mol Biol. 1999, 293 (3):595-611 5. Isupov MN,et al. &Littlechild JA. J Mol Biol. 2000, 299(4):1035-49 Acknowledgements: This work was supported by the French Centre national de la recherché scientifique (CNRS), the Brittany Regional Council (ARED fellowship), the TOXNUC III programme (CEA) and the IDEALG project (ANR-10BTBR-04-02). We are indebted to the scientists from the SAMBA beamline of the SOLEIL synchrotron and to the staff of the European Synchrotron Radiation Facilities (ESRF, Grenoble, France), belonging to the beamline ID23-EH1 and to the Dutch-Belgian beamline (DUBBLE), for technical support during X-ray and XAS data collection and treatments.

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IL 3

Rational Design of Prospective Antiparasitic Oxidovanadium(IV) Compounds based on Quantitative Structure-Activity Relationships J. Beníteza, G. Scalesea, S. Rostána, J. Varelab, H. Cerecettob, M. Gonzálezb, A. Merlinoc, L. Coitiñoc, I. Correiad, J. Costa Pessoad, D. Gambinoa a

b

Cátedra de Química Inorgánica, Facultad de Química, UDELAR, Montevideo, Uruguay. Grupo de Química Medicinal, Laboratorio de Química Orgánica, Facultad de Ciencias-Facultad de Química, UDELAR, Uruguay. d Laboratorio de Química Teórica y Computacional, Facultad de Ciencias, UDELAR, Uruguay d Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal. e-mail: [email protected]

American trypanosomiasis (Chagas disease), caused by Trypanosoma cruzi, is a major health problem in Latin America leading to more deaths than any other parasitic disease. Furthermore, globalization and immigration of unknowingly infected people has also led to the appearance of infection cases in developed countries. The disease offers a big challenge for drug discovery since chemotherapy is based on old non-specific drugs that give rise to toxic effects, show limited efficacy and lead to development of resistance. Searching for prospective vanadium-based drugs against T. cruzi, we have developed a series of oxidovanadium(IV) heteroleptic complexes, [VO(L-2H)(NN)], that include different salicylaldehyde semicarbazone derivatives (L) and different polypyridyl DNA intercalators (NN) as ligands. Most of the complexes exert significantly higher in vitro activities against T. cruzi than the reference drug Nifurtimox and than the free semicarbazone and NN ligands, as well as high selectivity indexes for parasite / mammalian cells. Furthermore, the complexes show ability to interact with DNA in an intercalative mode, suggesting that this biomolecule may be a parasite target. Having a large number of structurally related compounds quantitative structure-activity relationships were established. The correlation highlighted the relevance of lipophilicity but also reflected the significance of the NN structure on the anti-T. cruzi effect. To further evaluate the effect of the nature of the intercalative polypyridyl chelator on the biological profile and considering the QSAR study as a design guide, the series has been expanded by including 3,4,7,8tetramethyl-1,10-phenanthroline as NN ligand and chloro- and dibromo- salicylaldehyde semicarbazone derivatives as the coligand L. Results from the characterization of the new compounds in the solid state and in solution, biological evaluation and interaction with DNA, studied by fluorescence and docking methods, are compared with those of the previously developed series. References 5. Gambino, D. Coord. Chem. Rev. 2011, 255, 2193– 2203. 6. Benítez, J.; Becco, L.; Correia, I.; Milena Leal, S.; Guiset, H.; Costa Pessoa, J.; Lorenzo, J.; Tanco, S.; Escobar, P.; Moreno, V.; Garat, B.; Gambino D. J. Inorg. Biochem. 2011, 105, 303-311. 7. Fernández, M.; Becco, L.; Correia, I.; Benítez, J.; Piro, O. E.; Echeverria, G. A.; Medeiros, A.; Comini, M.; Lavaggi, M. L.; González, M.; Cerecetto, H.; Moreno, V.; Costa Pessoa, J.; Garat, B.; Gambino, D. J. Inorg. Biochem. 2013, 127, 150-160. 8. Fernández, M.; Varela, J.; Correia, I.; Birriel, E.; Castiglioni, J.; Moreno, V.; Costa Pessoa, J.; Cerecetto, H.; González, M.; Gambino D. Dalton Trans. 2013, 42, 11900-11911. Acknowledgements: Authors thank CYTED networks RIIDFCM and RIDIMEDCHAG, CSIC-UdelaR, FCT, the Portuguese NMR Network and PEst-OE/QUI/UI0100/2013.

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IL 4

High-Frequency and -Field EPR Spectroscopy of Vanadium(III): from Curiosity to Practicality J. Krzysteka a

National High Magnetic Field Laboratory (NHMFL), Florida State University Tallahassee, FL 32310, USA e-mail: [email protected]

Among the multiple oxidation states of vanadium, many of them paramagnetic, V(III) has traditionally posed serious obstacles to Electron Paramagnetic Resonance (EPR) spectroscopists. The main reason was its 3d2 electronic configuration, with the resulting non-Kramers (integer) spin state of S = 1. While the S = 1 spin state in itself is not an impediment to EPR detection, its accompanying zero-field splitting is, making V(III) “EPR-silent” at conventional frequencies such as X-band (9 GHz). It was only with the availability of frequencies approaching 1 THz, and magnetic fields reaching 25 Tesla or more that successful detection and characterization of V(III) in coordination complexes became a possibility about 10 years ago [1]. The papers that followed were of largely exploratory nature, following a fairly steep learning curve [2-3]. The progress, however, has been quite rewarding, and EPR detection and characterization of V(III) has become more or less routine and the obtained results can be used for increasingly practical purposes. In my talk I will attempt to summarize that progress, illustrating it with experimental (and some theoretical) results, both published [1-4] and unpublished [5-6]. It appears that high-frequency and field EPR (HFEPR) has by now become an established spectroscopic toolin investigating electronic and magnetic properties of V(III) coordination complexes as well as their other properties such as chemical reactivity. References 1. Krzystek, J.,et al.,Inorg. Chem.2004, 28, 322-325. 2. Telser, J.,et al., J. Inorg. Biochem. 2009, 103, 487-495. 3. Ye, S., et al.,Inorg. Chem.2010, 49, 977-988. 4. Horton, D.C., et al., Inorg. Chim.Acta2014, in print (DOI: 10.1016/j.ica.2013.12.001). 5. Brynda, M., et al., NHMFL Research Report,2007. 6. Islam, M.N., et al., NHMFL Research Report, 2010. Acknowledgements: The following people heavily contributed to this work: J. Telser (Roosevelt University, Chicago), Hua-Fen Hsu (National Cheng Kung University, Tainan, Taiwan), A. A. Holder (Old Dominion University, Norfolk), D. C. Crans (Colorado State University, Fort Collins). Theexperimental work was done at the NHMFL, which is funded by the NSF through Cooperative Agreement DMR 1157490, the State of Florida, and the USDept. of Energy.

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IL 5 A Vanadium Substituted Polyoxometalate, H5PV2Mo10O40 as a Catalyst for Electron Transfer-Oxygen Transfer Oxidations. A Unique Compound for Unique Transformations R. Neumann Department of Organic Chemistry, Weizmann Institute of Science, Rehovot, Israel 76100 e-mail: [email protected]

In the year 2000, it was discovered that the polyoxometalate, H5PV2Mo10O40, and a few similar analogues could serve as an oxygen donor towards activated arenes and alkylarenes.1 Analysis of the reaction by various kinetic and spectroscopic tools revealed that the reactivity could be explained an electron transfer-oxygen transfer (ET-OT) mechanism wherein electrons are transferred from the organic substrate to the catalyst and oxygen is transferred from the polyoxometalate to the organic substrate.2 Importantly the catalyst can be re-oxidized with O2 to form water. Since then we have studied the reactivity of this compound/catalyst in many reactions. In this talk I will discuss the following aspects. 1. H5PV2Mo10O40 catalyzes a unique oxidative C-C bond cleavage of primary alcohols to yield the corresponding aldehydes as initial products, eg propanal and formaldehyde from 1-butanol. Similar bond cleavage reactions of vicinal diols also occur.3 2. This finding has now led to method for the complete transformation of important biomass carbohydrate resources such as cellulose and hemicellulose to CO and H2.4 3. Similarly, we are now able to selective oxidize toluene and its substituted derivatives to the corresponding aldehydes.5 4. We have found that H5PV2Mo10O40 catalyzes the insertion of oxygen in metal-carbon bonds leading to a possible new pathway for the functionalization of alkanes.6 5. EPR and computational techniques have allowed an understanding of the importance of coordinatively unsaturated species as reactive intermediates in ET-OT reactions.7,8

References 1. A. M. Khenkin, R. Neumann, Angew. Chem. Int. Ed.2000, 39, 4088-4090 2. A. M. Khenkin, L. Weiner, Y. Wang, R. Neumann, J. Am. Chem. Soc. 2001, 123, 8531-8542. 3. A. M. Khenkin, R. Neumann J. Am. Chem. Soc. 2008, 130, 14474–14476. 4. B. B. Sarma, R. Neumann, submitted for publication. 5. B. B. Sarma, R. Neumann, submitted for publication. 6. A. M. Khenkin, I. Efremenko, J. M. L. Martin, R. Neumann, J. Am. Chem. Soc. 2013, 135, 19304–19310. 7. I. Kaminker, H. Goldberg, R. Neumann, D. Goldfarb, Chem. Eur. J. 2010, 16, 10014-10020. 8. I. Efremenko, R. Neumann, J. Am. Chem. Soc. 2012, 134, 20669–20680.

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IL 6 The Role of Vanadium in Mixed Oxides Catalysts for Gas-phase One-pot Reactions F. Cavani a

Università di Bologna, Dipartimento di Chimica Industriale “Toso Montanari”, Viale Risorgimento 4, 40136 Bologna, Italy e-mail: [email protected]

Vanadium oxide is a key component in several industrial catalysts for gas-phase redox-type reactions, such as the oxidation of o-xylene to phthalic anhydride (V2O5/TiO2), acrolein to acrylic acid (Mo/V/W/O), n-butane to maleic anhydride (V/P/O), methacrolein to methacrylic acid (P/V/Mo/O polyoxometalates), and the ammoxidation of propane to acrylonitrile (Mo/V/Nb/Sb/O and V/Sb/O).1 Other systems based on V are currently being investigated for various gas-phase reactions, such as the oxidehydrogenation of alcohols and alkanes, the oxidation of isobutane to methacrylic acid and of methane to formadehyde. In some cases, Vanadium plays its catalytic role within complex reaction networks, in which various transformations occur. Some examples will be here discussed, showing out the proper combination of V redox properties with either acidic or basic properties provided by selected elements in bifunctional catalysts, may finally lead to the optimal performance in various one-pot reactions. Examples include: 1. Vanadyl pyrophosphate catalyst for the oxidation of n-butane, where the acid properties are needed for the activation of the substrate and the redox properties of V ions are required to achieve high selectivity to maleic anhydride, and low selectivity to carbon oxides.2,3 2. W/V/O bronzes with hexagonal structure, catalysts for the oxidehydration of glycerol to acrylic acid, where acid properties are required for the dehydration of glycerol to acrolein, whereas V ions oxidize acrolein into acrylic acid.4,5 3. V/Fe/O mixed oxides with the spinel structure, catalysts for the gas-phase ring-alkylation of phenol with methanol, in which the combination of basic and dehydrogenating properties, the former being required for the activation of phenol, the latter for the in-situ generation of formaldehyde and the hydrogenolysis of the intermediate compound formed by phenol ringhydroxymethylation, finally lead to excellent yield to o-cresol. References 1. Cavani, F., Teles, J.H. ChemSusChem 2009, 2, 508-534. 2. Cavani, F., Luciani, S., Degli Esposti, E., Cortelli, C., Leanza, R. Chem. Eur. J. 2010, 16, 1646-1655. 3. Caldarelli, A., Bañares, M.A., Cortelli, C., Luciani, S., Cavani, F. Catal. Sci. Techn. 2014, 4, 419-427. 4. Dolores Soriano, M., Concepcion, P., Lopez Nieto, J. M., Cavani, F., Guidetti, S., Trevisanut, C. Green Chem. 2011, 13, 2954-2962. 5. Chieregato, A., Dolores Soriano, M., Basile, F., Liosi, G., Zamora, S., Concepción, P., Cavani, F., López Nieto, J.M. Appl. Catal. B 2014, 150-151, 37-46.

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IL 7 Vanadium Catalysts in Alkane Partial Oxidation A. J. L. Pombeiro Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal e-mail: [email protected]

The partial oxidation and other functionalization reactions of alkanes, under mild conditions, constitute a challenging field of research in view of the high inertness of these compounds which, therefore, are normally used as non-renewable fossil fuels. Their selective conversion into functionalized organic compounds can disclose an alternative application which still remains to be achieved. Vanadium catalysts have been playing an important role towards that aim and recent results obtained in this field in the author´s Laboratory will be described, namely concerning the following main types of: - Catalyst precursors: oxo-V complexes with (i) azine fragment ligands, (ii) N,O-ligands or (ii) scorpionate (trispyrazolylmethane derived) ligands; oligovanadates; multinuclear mixedvalence(IV,V) oxo-V-complexes; mixed N,S-ligand V complexes; - Reactions: (i) peroxidative oxidations of liquid alkanes to alcohols and ketones, with H2O2, organoperoxides or peracids; (ii) oxidations of gaseous alkanes to alcohols, aldehydes, ketones or acids; (iii) carboxylations with CO and a peroxide. Both homogeneous and supported systems will be described, as well as kinetic and DFT studies. The role of water will be analyzed, namely in water assisted mechanisms. References 1. M. Sutradhar, A. J. L. Pombeiro, Coord. Chem. Rev., 2014, 265, 89. 2. A.J.L. Pombeiro, in “Advances in Organometallic Chemistry and Catalysis”, A. J. L. Pombeiro (ed.), J. Wiley & Sons, Ch.2, 2014, pp. 15-25. 3. J.A.L. da Silva, J.J.R. Fraústo da Silva, A.J.L. Pombeiro, Coord. Chem. Rev., 2013, 257, 2388 4. M. Sutradhar, N.V. Shvydkiy, M.F.C. Guedes da Silva, M.V. Kirillova, Y.N. Kozlov, A.J.L. Pombeiro, G. B. Shul’pin, Dalton Trans., 2013, 42, 11791 5. M. Sutradhar, M. Kirillova, M.F.C. Guedes da Silva, L. Martins, A.J.L. Pombeiro, Inorg. Chem., 2012, 51, 11229 6. S. Gupta, M.V. Kirillova, M.F.C. Guedes da Silva, A.J.L. Pombeiro, Appl. Cat. A: Gen., 2013, 460-461, 82 7. T.F.S. Silva, T.C.O. Mac Leod, L.M.D.R.S. Martins, M.F.C. Guedes da Silva, M.A. Schiavon, A.J.L. Pombeiro, J. Mol. Cat. A: Chem., 2013, 367, 52 8. M.V. Kirillova, M.L. Kuznetsov, Y.N. Kozlov, L.S. Shul’pina, A. Kitaygorodskiy, A.J.L. Pombeiro, G.B. Shul’pin, ACS Catalysis, 2011, 1, 1511 9. T.F.S. Silva, K.V. Luzyanin, M.V. Kirillova, M.F. Guedes da Silva, L.M.D.R.S. Martins, A.J.L. Pombeiro, Adv. Synth. Cat., 2010, 352, 171. Acknowledgements: The co-authors of the cited references are greatly acknowledged. The work has been partially supported by the Fundação para a Ciência e a Tecnologia (FCT), Portugal, and the Pest-OE/QUI/UI0100/2013 project.

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IL 8 Initial Steps for the Development of de novo designed Vanadium Haloperoxidases H. Qayyuma, L. Heiland, C. Mocnya, V.L. Pecoraroa a

Department of Chemistry, University of Michigan, Ann Arbor, MI USA 48109-1055 e-mail: [email protected]

de Novo protein design has been utilized recently to generate a wide array of enzymatic activities using metal ions.1 In all cases, recognition of the metal co-factor has focused on multiple direct metal heteroatom bonds from endogenous ligands presented at the active site. In contrast, efforts to recognize polyoxoanions such as vanadate or complex ions such as vanadyl ions have not been explored. In this presentation, we will discuss ways of making three stranded coiled coil peptides that incorporate positively charged amino acid residues into the hydrophobic interior of these aggregates in an effort to build a site that might recognize VO43- solely based on electrostatic interactions. We will also examine the binding of vanadyl ion to peptides containing histidine groups. In this last regard, we will describe a method to prepare heterotrimeric coiled coils that can be used to incorporate a single histidine residue to more closely mimic vanadium binding in vanadium haloperoxidases. The studies reported here are the foundational work that will hopefully one day lead to protein derived models capable of binding vanadium in aqueous solution. References 1. Yu, F.; Cangelosi, V.M.; Zastrow, M.L.; Tegoni, M.; Plegaria, J.S.; Tebo, A.G.; Mocny, C.S.; Ruckthong, L.; Qayyum, H.; Pecoraro, V.L. Chem. Rev., ASAP , Publication Date (Web): March 24, 2014, DOI: 10.1021/cr400458x. Acknowledgements: This work was funded by the National Institutes of Health (ES012236).

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ORAL COMMUNICATIONS

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O1 Vanadium sorption in soils M. A. Larssona, D. Berggren Klejaa, J. P. Gustafssona a

Swedish University of Agricultural Sciences, Department of Soil and Environment, Uppsala, Sweden. e-mail: [email protected]

The input of vanadium to soils is mainly from burning of fossil fuels. Additions of by-products produced by the steel industry, e.g. as soil amendments, can locally augment the vanadium soil concentration. The sorption behavior of elements to different soil constituents in soils is important for understanding transport and bioavailability in the soil-water system. However, only little research has been made on vanadium sorption in soils. Previous studies have shown that metal (hydr)oxides, especially those containing iron, are important for vanadium sorption1,2. Other factors that affect vanadium sorption are soil pH, clay and organic matter content3,4. The aim with this study was to determine vanadium sorption isotherms for 25 different soils and based on those results, to develop a model that predict vanadium sorption to a range of soils. The selected soils had a pH range from 4.5 to 8.5, an amorphous iron content between 0.1 and 25.9 g kg1 and a clay content from 2 to 56 %. The sorption was established for each soil by batch experiments where pentavalent vanadium (H2VO2-)was added at concentrations between 12.5and 300µM to aliquots of soil and equilibrated for 6 days. Freundlich sorption isotherms were thereafter established for each soil (figure). Speciation analysis were performed on some of the soils and solutions after equilibration and showed that the main fraction of the added vanadium remained pentavalent. There was an increasing vanadium sorption with increasing concentration of amorphous iron (hydr)oxides. Further, there was a positive correlation with clay content, which may be attributed to the increase in iron (hydr)oxides with increasing clay concentrations.

References 1. Naeem, A., Westerhoff, P. & Mustafa, S. Water Res.2007, 41, 1596-1602. 2. Larsson, M. A., Baken, S., Gustafsson, J. P., Hadialhejazi, G. & Smolders, E. Environ. Toxicol. Chem.2013, 32, 2266-2273. 3. Gäbler, H.-E., Glüh, K., Bahr A.& Utermann, J. J.Geochem. Explor. 2009, 103, 37-44. 4. Lu, X., Johnson, W. D. & Hook, J. Environ. Sci. Technol.1998, 32, 2257-2263. Acknowledgements: This work was funded byMerox, LKAB and Ruukki.

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O2 Human Health Hazards and the Lack thereof of Vanadium Substances Differing in Solubility and Valence R. V. Battersbya, A. Voigta, K. Kumerschekb, D. Schellc a

EBRC Consulting GmbH, Hannover, Germany. b Treibacher Industrie AG, Althofen, Austria. c GfE Metalle und Materialien GmbH, Nuernberg, Germany. e-mail: [email protected]

All EU manufacturers and importers of chemical substances are required to submit a registration under EU Regulation 1907/2006 (REACH), including a comprehensive assessment of human-health hazards. Vanadium substances considered for REACH registration include vanadium metal and various substances including oxides, sulfates, vanadates and other salts, involving tri-, tetra- and pentavalent species. For the human-health hazard assessment, a comprehensive characterisation of physico-chemical parameters and the toxicological potential of each vanadium substance is required. Substancespecific data were generated to address physico-chemical endpoints and toxicological effects. Further, solubility and bioaccessibility testing, including redox speciation measurements, were conducted with all vanadium substances in water as well as with selected representatives in synthetic physiological media. Toxicological data indicate substantial differences in the potential of vanadium substances to elicit local and acute effects, including skin and eye irritation. Some of these differences may be explained with the varying solubility of vanadium substances as well as acid/base properties. An overview of relevant physico-chemical parameters and acute and local toxicological effects of different vanadium substances will be provided and the relevance of these findings for the humanhealth hazard assessment will be discussed. Acknowledgements: We thank the Vanadium Consortium for funding this research. The data may not be freely used to comply with regulatory requirements such as REACH without the formal agreement of the Vanadium Consortium.

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O3 Anti-amoebic Activity of Vanadium Complexes A. Kumara,c, M. R. Mauryab, J. Costa Pessoaa a

Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal. a Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee-247667, India. c Center for Nano & Material Science, Jain University, Jakkasandra P, Bangalore– 562112, Karnataka, India. e-mail: [email protected]

Vanadium complexes showed encouraging results on the in-vitro anti-amoebic activity. Amoebiasis is the infection of the human gastrointestinal tract by Entamoeba histolytica, a protozoan parasite that is capable of invading the intestinal mucosa and can infect almost every organ of the body. We presents synthesis, characterization and reactivity of dioxido and oxidovanadium(V) complexes with Schiff base ligands containing the ONS donor atoms. In order to obtain information on the therapeutic potentiality of these complexes, in-vitro screening of the anti-amoebic activity of these complexes against HM1:1MSS strain of E. histolytica have been carried out. The efficacy of the metal-based therapeutic agent changes considerably by making small changes in the organic ligands attached to the metal center.

Life cycle of Entamoeba histolytica References 1. Maurya, M.R., Haldar, C., Khan, A., Azam, A., Salahuddin, A., Kumar, A., Costa Pessoa, J. Eur. J. Inorg. Chem. 2012, 2560 – 2577. 2. Maurya, M.R., Khan, A., Azam, A., Ranjan, S., Mondal, N., Kumar, A., Avecilla, F., Costa Pessoa, J. Dalton. rans., 2010 1345–1360. 3. Maurya, M.R., Khan, A., Azam, A., Kumar, A., Ranjan, S., Costa Pessoa, J. Eur. J. Inorg. Chem. 2009, 35, 5377–5390. 4. Maurya, M.R., Kumar, A., Abid, M., Azam, A. Inorg. Chim. Acta., 2006, 359, 2439–2447. 5. Maurya, M.R., Kumar, A., Bhat, A.R., Azam, A., Bader, C., Rehder, D., Inorg. Chem., 2006, 45, 1260–1269. Acknowledgements: JCP and AK thank Fundação para a Ciência e Tecnologia, the Portuguese NMR Network (ISTUTL Center), PEst-OE/QUI/UI0100/2013 and grant SFRH/BPD/90976/2012, MRM, thank the Department of Science and Technology, the Government of India.

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O4 Investigations on the Human Relevance of Vanadium Pentoxide-induced Mouse Lung Tumors B. Bhaskar Gollapudia, and J. A. MacGregorb a

b

Exponent, Inc., Midland, MI, USA Toxicology Consulting Services, Bonita Springs, FL USA e-mail: [email protected]

In a long-term inhalation bioassay conducted by the U. S. National Toxicology Program (1), vanadium pentoxide (VP) induced clear evidence of treatment-related lung tumors in both male and female B6C3F1 mice, but not in F 344N rats. However, the observed increases were not doserelated across the groups with the dose response being flat across the concentration range tested (i.e., 1, 2, and 4 mg/m3), thus limiting the utility of these data to predict cancer risk at environmentally relevant low exposure concentrations. A series of investigations was launched in order to gain insight into the mode of action (MoA) responsible for the etiology of mouse lung tumors and their relevance to humans. To rule in or rule out a mutagenic MoA, a study was conducted to examine the induction of DNA strand breaks (Comet assay) in lung tissue and bronchiolar lavage fluid following repeated inhalation exposure. To determine if VP causes gene mutations, transgene (cII ) and endogenous gene (K-Ras) mutations of Big Blue mice are being measured in lung tissue from VP exposed mice. No evidence in support of this MoA emerged from the results obtained so far (2), a finding consistent with the weight of evidence suggesting a general lack of in vivo genotoxicity for VP. In order to further cast a wider net to develop plausible hypothesis on potential MoAs, the Affymetrix whole genome microarray transcriptomic data from mice exposed to 2 mg/m3 VP for 13 weeks (3) was assessed. These analyses indicated that VP exposure primarily disturbed pathways involved in lipid metabolism with no specific discernable effects on cell cycle regulation, signaling or DNA-repair pathways. There is some evidence from the studies conducted so far implicating a role for oxidative stress and/or inflammation in the mouse lung tumors produced by VP exposure. In summary, these and other ongoing studies will assist in the development of a framework to assess the relevance, or lack thereof, of lung tumors observed in B6C3F1 mice following high dose inhalation exposures to vanadium pentoxide. References 1. National Toxicology Program (2002):, NTP, 2002, TR 507, NIH publication no. 03-444. 2. Schuler D, Chevalier HJ, Merker M, Morgenthal K, Ravanat JL, Sagelsdorff P, Walter M, Weber K, McGregor D. J Toxicol Pathol. 2011, 24, 149-62. 3. Thomas RS, Bao W, Chu TM, Bessarabova M, Nikolskaya T, Nikolsky Y, Andersen ME, 4. Wolfinger RD. Toxicol Sci.2009, 112, 311-21. Acknowledgements: This work was funded by the Department of Defense (DoD) under a cooperative agreement that is awarded and administered by the U.S. Army Medical Research and Materiel Command (USAMRMC) and the Telemedicine & Advanced Technology Research Center (TATRC), Fort Detrick, Maryland 21702, under Contract Number: W81XWH-09-2-006.

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O5 Vanadium in Phosphatases: Using a “Magnifying Glass” for Viewing Inhibitor Binding at the Active Site C. C. McLauchlana and D. C. Cransb a

Department of Chemistry, Illinois State University, Normal, IL,USA Department of Chemistry, Colorado State University, Fort Collins,CO,USA e-mail: [email protected]

b

Vanadate and vanadium compounds are known inhibitors for phosphorylases and phosphatases. Early discoveries include the investigations characterizing the vanadate impurity found in ATPases preparations initially causing variability in the enzyme activity of this product. 1Recently, a range of vanadium complexes have been shown to inhibits phosphatases, including a number of different ligands, some which have been found to remain on the vanadium as the enzymes are inhibited. 27 The hydrolysis of phosphate monoesters depending on the protonation state follow an associative five-coordinate transition state geometry of the general formula VO4X, which for the phosphate systems is generally considered to be trigonalbipyramidal. Five coordinate geometries for transition metal ions such as vanadium generally, however, are often found to be between the idealized square planar and trigonalbipyramidal geometries, Figure 1. However, other coordination geometries and other metal complexes have been characterized as inhibitors, suggesting that the structural features are not the sole reason for the observed potency in the complexes. Many model complexes have been synthesized to model the VO4X geometry. Here we present an analysis of the structural parameters from X-ray crystallography of five-coordinate vanadium complexes with a VO4X coregeometry (X = C, N, O, Cl, F, S, N, O) and comparing this to the vanadium-based inhibitors crystalized inside various phosphatases. We will compare each structure to the ideal transition state geometry for phosphate ester hydrolysis, to evaluate the importance of the small structural pertubation in small molecule structures and inside a protein.

References 1. Cantley, Jr., L. C.; Resh, M. D.; Guidotti, G. Nature1978, 272, 552-554. 2. Posner, B. I.; Faure, R.; Burgess, J. W.; Bevan, A. P.; Lachance, D.; Zhang-Sun, G.; Fantus, I. G.; Ng, J. B.; Hall, D. A.; Lum, B. S. J. Biol. Chem. 1994,269, 4596-4604. 3. Crans, D.C.;Keramidas, A.D.;Drouza,C.Phosphorus, Sulphur, and Silicon1996, 109-110, 245-248. 4. McLauchlan, C.C.; Hooker, J.D.; Jones, M.A.; Dymon, Z.; Backhus, E.A.; Greiner, B.A.; Dorner, N.A.; Youkhana, M.A.; Manus, L.M. J. Inorg. Biochem.2010, 104, 274-281. 5. Lu, L.; Yue, J.; Yuan, C.; Zhu, M.; Han, H.; Liu, Z.;Guo, M. J. Inorg. Biochem.2011, 105, 1323-1328. 6. Lu, L.; Gao, X.; Zhu, M.; Wang, S.; Wu, Q.; Xing, S.; Fu, X.; Liu, Z.; Guo, M.BioMetals2012,25 (3), 599610. 7. Yang, X.-G.; Wang, K. In Biomedical Inorganic Polymers, Müller, W. E. G.; Wang, X.; Schröder, H. C., Eds. Springer Berlin Heidelberg: 2013; Vol. 54, pp 1-18.

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O6 The role of vanadium chloroperoxidases in the formation of chloroform and the impact on the environment R. Wever Van ‘t Hoff institute for Molecular Sciences, University of Amsterdam, The Netherlands e-mail: [email protected]

There is substantial evidence that bromoform (CHBr3) which is formed in oceans and sea’s and ventilated to the atmosphere is indirectly produced by vanadium bromoperoxidases present in seaweeds, phytoplankton and cyanobacteria.[1] In the biosynthetic pathway oxidized bromine species generated by the vanadium enzymes react with dissolved organic matter in seawater to form intermediate brominated compounds. These unstable compounds decay via a haloform reaction to a variety of volatile brominated compounds of which bromoform is the major component. Chloroform (CHCl3) and other chlorinated compounds are also natural compounds and found in various aquatic and terrestrial environments. According to Leri and Myneni [2] the production of natural organochlorine appears to be associated with the decomposition of plant material on the soil surface, though the chlorine cycle budget also indicates that a proportion of natural organochlorine enters soil through plant litter. It is well known that a large group of fungi, the dematiaceous hyphomycetes which are found in plant material and soils contain vanadium chloroperoxidases e.g. Drechslera biseptata, D. subpapendorfii, Embellisia didymospora, and Ulocladium chartarum. Many of these hyphomycetes are phytopathogenic and/or saprophytes and grow on plants and decaying wood. We proposed previously that the physiological role of the vanadium chloroperoxidases is to generate HOCl which is used by the fungus as an attack mechanism. [3] In this case to oxidize either the lignocellulose in the cell walls of the plant in order to facilitate penetration of the fungal hyphen into the host or to oxidize the protective cuticle, the waxy layer on the leaves of plants facilitating entry of the fungus into plant cells. It is very likely be that HOCl generated by these fungi reacts with organic matter resulting in the formation of the organochlorines. Since chloroperoxidase producing fungi are ubiquitous in decaying lignocellulose and plant debris
and occur widely in nature these enzymes have roles in the natural production of
 chloroaromatics and low molecular weight organochlorines which may decay to chloroform.[4] In this contribution we will try to shed light on the biosynthetic pathways leading to the formation of these chlorinated compounds in the terrestrial environment and role of the vanadium chloroperoxidases. References 1. Wever, R., Van der Horst, M. A. Dalton Trans. 2013, 42, 11778-11786. 2. Leri , A. C and Myneni, S. C. B. Global Biochem. Cycles. 2010, doi:10.1029/2010GB003882. 3. Barnett, P., Kruitbosch, D. L., Hemrika W., Dekker, H. L., Wever, R. Biochim. Biophys. Acta 1997, 1352, 7384. 4. Ortiz-Bermudez, P., Hirth, K. C., Srebotnik, E., Hammel, K. E. Proc. Natl. Acad. Sci. USA, 2007, 104, 38953900.

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O7 X-Ray Absorption Spectroscopic Studies of Vanadium-containing Haloperoxidases M. C. Feitersa, A. Longob, D. Banerjeeb, S. Belinc, P.-L. Solaric, W. Meyer-Klaucked, J.-B. Fourniere, M. Czjzeke, C. Leblance a

Radboud University Nijmegen, Institute for Molecules and Materials, Nijmegen, The Netherlands b DUBBLE-CRG, European Synchrotron Radiation Facility, Grenoble, France c Synchrotron Soleil, Gif-sur-Yvette, France d Faculty of Science, Department of Chemistry, University of Paderborn, Paderborn, Germany e Station Biologique, Roscoff, France e-mail: [email protected]

Haloperoxidases are enzymes that contain vanadate in their active site [1] and are implicated in the efficient accumulation of iodine and bromine by brown algae such as Laminaria digitata (oarweed) and Ascophyllum nodosum (knotted wrack). We are interested in structure-function relationships for these enzymes, in particular in the reasons why iodoperoxidase has iodide as its preferred substrate and bromoperoxidase can also activate bromide. In this respect it is of interest to compare the algal bromoperoxidases to the recently discovered iodoperoxidase from the microorganism Zobellia galactanivorans and mutants thereof [2]. X-ray absorption spectroscopy (XAS) is applied to study the coordination geometry of transition metals in enzymes, and changes in it during catalysis [3]. It can also be applied to non-invasively study halogens in whole organisms [4], parts thereof [5], or isolated enzymes [6]. The so-called X-ray Absorption Near-Edge Structure (XANES) at and near the absorption edge of an element of interest gives information on the valence state and coordination geometry, the Extended X-ray Absorption Fine Structure (EXAFS) beyond the edge can be interpreted in terms of type- distance and number of the surrounding ligands. We have measured and interpreted the EXAFS and XANES of haloperoxidases at various edges (V, I, Br) and compared the results with protein crystallographic information where available [2, 7]. References 1. Vilter, H. in Vanadium and its Role in Life (Sigel H., Sigel, A., Eds.; M. Dekker: New York) 1995; 31, 325362. 2. Delage, L. manuscript in preparation 3. Feiters, M. C., and Meyer-Klaucke, W. in Practical Approaches to Biological Inorganic Chemistry (R. R. Crichton and R. Louro, Eds.; Elsevier) 2013, 131-160. 4. Küpper, F. C. et al. Proc. Natl. Acad. Sci. USA 2008, 105, 6954-6958. 5. Küpper, F. C. et al. J. Exp. Bot. 2013, 64, 2653–2664 6. Feiters, M. C. et al. J. Am. Chem. Soc. 2005, 127, 15340-15341. 7. Weyand, M. et al., J. Mol. Biol. 1999, 293, 595-611. Acknowledgements: We thank the European Molecular Biology Laboratory Hamburg Outstation for access to the EMBL-EXAFS beamline and the European Commission for support in the Research Infrastructure Action under FP6, the Dutch Research Council (NWO) for access to the Dutch-Belgian beamline (DUBBLE) at the ESRF, and SOLEIL synchrotron for access to the SAMBA beam line. This work was supported by the French Centre national de la recherché scientifique (CNRS), the Brittany Regional Council (ARED fellowship) and the TOXNUC III programme (CEA).

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O8 V-catalyzed bromination of thymol: enzymatic vs. chemical catalysis F. Sabuzia, P. Gallonia, F. Hollmanb, B. Florisa, I. W.C.E. Arendsb, V. Contea a

Department of Chemical Sciences and Technology, University of Roma Tor Vergata. Via della Ricerca Scientifica, snc, 00131 Roma, Italy b Delft, Department of Biotechnology, Julianalaan 136, 2628 BL Delft, The Netherlands e-mail: [email protected]

Vanadium peroxides, formed upon reaction between vanadium derivatives and hydrogen peroxide, are very effective oxidants of different substrates. Peroxido-vanadium complexes can oxide bromide ions to reactive species that can brominate organic substrates [1]. This process mimics the activity of haloperoxidases enzymes (HalPO). Between them, vanadate dependent bromoperoxidase, a metal-enzyme containing vanadium (V) in the active site, catalyzes the oxidation of halide ions, such as bromide and iodide, by hydrogen peroxide [2]. This activity is related to the formation of a peroxido vanadium species in the active site of the enzyme, which is a stronger oxidant than H2O2. In this poster the oxidative bromination of thymol, a phenolic terpenoid compound main component of the Thymus vulgaris essential oils, catalyzed by vanadium (V) will be presented. This "green" process occurs with no organic solvents, in very mild conditions and with sustainable reagents. OH

OH

OH Br

BPO or NH4VO3 KBr, H2O2

Br

The reaction, performed using a commercially available vanadium (V) catalyst, showed good results in terms of substrate conversion and selectivity toward the formation of 4-bromothymol. To compare the chemical reaction with the enzymatic one, we performed the oxidative bromination with the V-BrPO enzyme isolated from brown algae Ascophyllum nodosum. In this latter case, we obtain 2-bromothymol as main product, with yields lower than those obtained with the chemical system. References 9. Conte V., Floris B., Dalton Trans., 2011, 40 (7), 1419-1436; Conte V., Coletti A., Floris B., Licini G., Zonta C., Coord. Chem. Rev., 2011, 255, 2165-2177; Conte V., Coletti A., Mba M, Zonta C, Licini G, Coord. Chem. Rev., 2011, 255, 2345–2357. 10. Wischang D., Hartung J., Tetrahedron, 2012, 68, 9456-9463; Butler A., Carter-Franklin J. N., Nat. Prod. Rep., 2004, 21, 180-188. Acknowledgements: This work has been carried out in the framework of Cost Action CM1003 Biological oxidation reactions - mechanisms and design of new catalysts.

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O9 cis-2,6-Bis-(methanolate)-piperidine Oxovanadium(V) Complexes as Catalysts for Oxidative Alkenol Cyclization by tert-Butyl Hydroperoxide M. Amberg, M. Dönges, and J. Hartung Fachbereich Chemie, Organische Chemie, Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany. e-mail: [email protected]

Oxovanadium-(V)-complexes with piperidine derived ligands can be used to catalyze oxidative cyclization of alkenols by tert-butyl hydroperoxide (TBHP). The new piperidine-derived catalysts show an improved chemical inertness and improved reactivity for activating TBHP. Terminal dimethyl-substituted 4-pentenols afford 2-(tetrahydrofuran-2-yl)-2-propanols in notable 2,5-cis-selectivity, while 2-propenols give epoxides in up to 94% yield (Scheme 1). The oxidation of geraniol by TBHP, catalyzed by an oxovanadium-(V)-complex prepared from (2S,6R)-2diphenylmethanol-6-hydroxymethylpiperidine occurs enantioselectively. Summarizing the chemical progress made in synthesis of hydroxyl-substituted cyclic ethers from alkenols, we consider the new cis-2,6-bis-(hydroxymethyl)-piperidine complexes of oxovanadium(V) as promising leads for solving the standing problem on controlling stereoselectivity for oxidative tetrahydrofuran synthesis from alkenols. OH OH tBuOOH

HO

N H H H

+ VO(OEt)3

VOL(OEt)

OH

H2 L = CH3, Ph

O er up to 69:31

tBuOOH

H

O

H OH

OH

= H, CH3

dr up to 96:4

= e.g. alkyl, alkenyl, Ph

Scheme 1. Oxovanadium(V)-catalyzed cyclization and epoxidation of 4-pentenols and 2-propanols. References M. Dönges, M. Amberg, G. Stapf, H. Kelm, U. Bergsträßer, J. Hartung, Inorganica Chimica Acta, 2014, in press.

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O10 Mechanistic Approach of the Insulin Signaling Enhancement by Peroxidovanadium Complexes S. Matsugoa, H. Sugiyamaa, Y. Nishimotoa, H. Misub, T. Takamurab, S. Kanekob, Y. Kuboc, R. Saitoc, and K. Kanamoric a b

Institute of Science and Engineering, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa 920-1192, Japan Department of Disease Control and Homeostasis, Graduate School of Medical Science, Kanazawa University, 13-1 Takara-machi, Kanazawa, Ishikawa 920-8641, Japan c Department of Chemistry, Faculty of Science, University of Toyama, 3190 Gofuku, Toyama 930-8555, Japan

e-mail: [email protected]

Peroxidovanadium (V) complexes (pVs) are a topic of increasing interest especially focusing on their insulin-mimetic effects. We have synthesized two peroxidovanadium(V) complexes (pVs) having the amino acid moiety such as N-(4-imidazolylmethyl)-L-alanate (imala) or N-(4imidazolylmethyl)-L-phenylalanate (imphe) as an ancillary ligand and examined their physiological effects using H4IIEC3 rat hepatoma cell line. The pVs stimulated the proliferation of hepatoma cells at low dose concentration while they showed the cytotoxicity at high does concentrations. Next, we examined the signal transduction pathways induced by these compounds to clarify the molecular mechanism induced by these pVs. As a result, the cells treated with pVs generate the reactive oxygen species (ROS) in a dose-dependent manner. The activation of cellular stress signals was also observed in a dose-dependent manner, which suggests the key role of ROS generation in the signal transduction pathway and cell proliferation.

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O11 Vanadium(IV and V) hydroxyquinoline-containing complexes as potential antitumor and anti-mycobacterial agents I. Correiaa, M. Wabbaa, S. Roya, P. Adãoa, M. R. Mauryab, F. Marquesc, F. R. Pavand, C.Q.F. Leited, J. Costa Pessoaa a

Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av Rovisco Pais, 1049-001 Lisboa, Portugal b Department of Chemistry, Indian Institute of Technology Roorkee, India c Unidade Ciências Químicas e Radiofarmacêuticas, Instituto Superior Técnico, Polo de Loures-Campus Tecnológico e Nuclear, Sacavém, Portugal d Faculdade de Ciências Farmacêuticas, Universidade Estadual Paulista, Araraquara, SP, Brazil e-mail: [email protected]

Cancer is a leading cause of death and a priority in health research. Tuberculosis (TB) is also still a challenging worldwide health problem due to the emergence of multi-drug resistant strains of Mycobacterium Tuberculosis. Additionally, the association of TB and HIV infections has caused an alarming increase in TB and an urgent need for alternative chemotherapeutics for M. Tuberculosis infection. Hydroxyquinoline (HQ) is a privileged structural moiety present in many biologically active natural products, and is used as the source for many drugs prescribed for a wide range of pathologies. More specifically, 8-hydroxyquinoline has been mostly used for its capacity to strongly chelate metal ions, particularly Cu(II) and Zn(II). The antimicrobial activity of vanadium compounds has not been much explored and only a few studies have been published on vanadium complexes with activity against M. tuberculosis. [1-3] Taking this into consideration, as well as the importance of hydroxyquinolines in medicine, and the fact that metal complexes with drugs may display increased biological activity when compared to the free drugs, we developed mixed vanadium complexes containing 8-hydroxyquinoline and another ligand such as picolinic (or dipicolinic acid) or a Schiff base and investigated their biological activity. The complexes were fully characterized by UV–Vis, FTIR, EPR and 51V NMR spectroscopy, and X-ray diffraction, in selected cases. Their biological activity was assessed through cytotoxicity to A2780 human ovarian cancer cell line (IC50 value determination) and the minimal inhibitory concentration (MIC) of the compounds against Mycobacterium Tuberculosis. Action on HEK cells was also evaluated. Almost all tested complexes are very active against M. tuberculosis and the MICs are comparable to, or better than, MICs of ‘‘second line’’ drugs, such as streptomycin. Moreover, their cytotoxicity is comparable to the reference drug cisplatin. References 1. Maiti, S.; Ghosh, S. J. Inorg. Biochem. 1989, 36, 131. 2. David; Barros, V.; Cruz, C.; Delgado, R. FEMS Microbiol. Lett. 2005, 251, 119. 3. Maia, P.I.S.; Pavan, F.R.; Leite, C.Q.F.; Lemos, S.S.; Sousa, G.F.; Batista, A.A.; Nascimento, O.R.; Ellena, J.; Castellano, E.E.; Niquet, E.; Deflon, V.M. Polyhedron 2009, 28, 398–406. Acknowledgements: The authors thank FCT, the Portuguese NMR and MS Networks (IST Nodes), Investigador FCT and PEst-OE/QUI/UI0100/2013.

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O12 Experimental Charge Density Study of a Fluorescent Polyoxovanadate-Based Charge Transfer Hybrid X. Xua, S. Novakovićb, N. Bošnjaković-Pavlovićc, N. E. Ghermani d, Y. G. Wei e , A. Spasojević-de Biré *, a a

Laboratoire “Structures Propriétés et Modélisation des Solides”, UMR 8580 du CNRS, Ecole Centrale Paris, 92295 Châtenay-Malabry, France. b Faculty of Physical Chemistry, University of Belgrade, 11001 Belgrade, Serbia. c Laboratory for Theoretical and Condensed Matter Physics, Vinča Institute of Nuclear Sciences, Serbia; d Laboratoire “Physico-Chimie-Pharmacotechnie-Biopharmacie”, UMR 8612 du CNRS, Faculté de Pharmacie, Université Paris Sud 11, 5 Rue Jean-Baptiste Clement, 92296 Châtenay-Malabry, France. e Department of Chemistry, Tsinghua University, 100084 Beijing, China. e-mail: [email protected]

Polyoxovanadates (POVs) are very interesting kind of vanadium-containing compounds duo to fascinating electronic and magnetic properties, various thermodynamically stable redox isomers, and catalytic capabilities [1]. Recently, we found that POVs exhibit potential bioactivities and fluorescence properties [2]. Hexavanadate (V6) is one of important series of POVs, exists as inorganic-organic hybrid (Fig. 1), which had been extensively studied [2b, 3]. Experimental charge density analysis has been becoming a powerful tool used to investigate electron density distribution, topological analysis, AIM (Atom in Molecule) charge, electrostatic potential (EP), source function, etc. in the solid state [4]. Relationships investigation between structure and potential properties can provide a new insight into the mechanisms of these properties. We find that V6 is a charge transfer hybrid in which the V6 core is the electron-acceptor part, and the organic ligand is the donor part. Furthermore, to investigate the electronic properties of V6 hybrid, we have colored the molecular surface with EP values. The red part corresponds to a nucleophilic regions while the blue part is the most electrophilic regions. These informations could be useful for understanding the potent reactivity of V6 hybrid (Fig. 2).

Fig. 1 Structure of V6 hybrid

Fig. 2 Experimental EP (eÅ-1) on the molecular surface (0.01 eÅ-3)

References 1. a) Hayashi, Y. Coord. Chem. Rev. 2011, 255, 2270-2280; b) Daniel, C. J. Am. Chem. Soc. 2005, 127, 1397813987; c) Daniel, C. J. Am. Chem. Soc. 2009, 131, 5101 -5114; 2. a) Krstic, D. Gen. Physiol. Biophys. 2009, 28, 302–308; b) Yin, P. Angew. Chem. Int . Ed. 2011, 50, 2521– 2525; 3. Wu, P. Chem. Commun. 2011, 47, 5557-5559. 4. a) Koritsanszky, T. Chem. Rev. 2001, 101, 1583-1627; b) Gatti, C. Acta Cryst. 2004, A60, 438-449; c) Bošnjakovic-Pavlovic, N. Inorg. Chem. 2009, 48, 9742-9753; d) Bošnjakovic-Pavlovic, N. Crystal Growth & Design. 2011, 11, 3778-3789. Acknowledgements: Xiao Xu thanks China Scholarship Council (CSC) for supporting PhD study. Sladjana Novaković and Nada Bošnjaković-Pavlović thank Ecole Centrale Paris for invited professor position, which support their research in this domain.

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O13 Chiral Vanadium(V) Complexes with Schiff-Base Ligands: Characterization of Diastereomers in Solid State and Solution W. Plass Institute of Inorganic and Analytical Chemistry, Friedrich-Schiller-University, Jena, Germany. e-mail: [email protected]

Vanadium complexes play an important role in biological as well as in catalytic processes. In both cases chiral properties implemented by the ligand frame work can be relevant for specific properties of the systems. In general, this leads to the presence of diastereomers generated by the additional chiral center at the vanadium site [1]. We will present different vanadium(V) complexes with chiral Schiff-base ligands which are based on biologically and catalytically relevant amine components such as amino acids and 1,2diaminocyclohexane. These ligand systems can easily be modified in their back bone. Such ligands can form diastereomeric vanadium(V) complexes due to the flexible orientation of the oxido group at the vanadium center which can lead to two stereoisomers with either A or C configuration. By additional co-ligands both the formation and the kinetic stability of the generated diastereomeric complexes can be altered. The systems are characterized in solid state by X-ray crystallography and in solution by NMR spectroscopic methods. The assignment of possible isomers and conformers is supported by DFT calculations.

References 1. W. Plass, Coord. Chem. Rev. 2011, 255, 2378–2387. 2. G. Mohammadnezhad, M. Böhme, D. Geibig, A. Burkhardt, H. Görls, W. Plass, Dalton Trans. 2013, 42, 11812–11823.

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O14 Electron transfer in redox binary Hydroquinone/p-Semiquinone -V(III/IV/V) systems, structure and reactivity A. D. Keramidasa, C. Drouzab, M. Vlasiou,a M. Stylianoua a

b

University of Cyprus, Department of Chemistry, 1678 Nicosia, Cyprus Department of Agricultural Sciences, Biotechnology and Food Science, Cyprus University of Technology, Lemesos 3036, Cyprus e-mail: [email protected]

Enzymes exhibiting in the active site two redox centers one inorganic and one organic in close proximity, such as galactose oxidase and copper amine oxidase, utilizes O2 to oxidize organic substrates releasing H2O2. Synthesis of model compounds mimicking this activity is of particular interest for important applications. Such applications can be found in the use of O2 as green oxidant and in the facile production of H2O2 which is also a powerful green oxidant utilized for clean energy storage. The basis for these applications is derived by the ability of vanadium complexes to catalyze oxidation reaction utilizing O2 and/or H2O2, including, oxidative C-H activation, epoxidation and alcohol oxidation reactions in the form either of inorganic complexes or the metal centered active site of vanadium based enzymes. Our recent work has shown that ligation of bisiminodiacetate substituted hydroquinone ligands (L1) to vanadyl results in stabilization of p – semiquinone radicals in acidic aqueous solutions.1 These compounds mimic the activity of the two redox center enzymes and are good models for the exploitation of the biomolecules redox reaction mechanism. Investigation of the structure and reactivity of V(III/IV/V) - hydroquinonate complexes containing various chelating groups (L1, L2 and L3)1-3 showed that the stabilization of the radical is depended on the geometry of the metal binding site and the oxidation state of the metal. The vanadium hydroquinone/p-semiquinone electron transfer can be remotely controlled by pH (L1, L2) and by the temperature (L3). The metal – p-semiquinonate molecules are able to activate dioxygen resulting in the formation of H2O2 and thus, mimicking the oxidases activity.

References 1. Drouza, C., Keramidas, A. D. Inorg. Chem., 2008, 47, 7211-7224. 2. Drouza, C., Vlasiou, M., Keramidas, A. D. Dalton Transactions 2013, 42, 11831-11840. 3. Drouza, C., Stylianou, M., Papaphilippou, P., Keramidas, A. D. Pure Appl. Chem., 2013, 85, 329-342.

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O15 Characterization of biological origin Vanadium for nuclear physics applications S. Nagornya, M. Ferrantea, M. Laubensteina, S. Nisia, T. Uekib a

INFN - Laboratori Nazionali del Gran Sasso, Assergi, Italy Department of Biology, Graduate School of Science, Hiroshima University, Japan e-mail: [email protected]

b

In nature there are a number of isotopes, which are considered as "stable" (with half-lives greater than the life-time of the Universe, i.e. more than 1.25×1010 y), but for which, however, the radioactive decay is energetically allowed. Among rare decay processes with an extremely long half-life that can occur for these nuclides could be attributed also extremely forbidden beta decays, i.e. where the level of the parent nucleus from which decay occurs, has a very different angular momentum and parity in comparison to the final level of the daughter nucleus. The natural vanadium isotope 50V, is one of only three isotopes, for which a non-unique 4-fold forbidden (i.e. the parity of the decay does not change, I = 4+) beta decay may occur. The other isotopes are 113Cd and 115In. Theoretical half-life estimations for 50V exceed 1017 years. When one tries to detect such a decay, it will, of course, produce only a very weak counting rate in the detection system. The experiments dedicated to search for such rare decays have to be performed in underground laboratories, well-shielded from external background, using ultra-low background detectors and specimens of Vanadium with the lowest possible concentration of natural radionuclides (40K, 232Th and 238U), in order to reach the highest level of sensitivity. Typically vanadium is extracted from ores and always contains a relatively large amount of uranium and thorium. As an alternative way to obtain vanadium, it was extracted from Ascidia sydneiensis samea cells by centrifugal fractionation of vanadium-storing cells. Afterwards it was measured by means of High Resolution Inductively Coupled Plasma-Mass Spectrometry (HR-ICPMS), using a mass spectrometer Thermo Fisher Scientific ELEMENT2 at the Gran Sasso National Laboratory. The concentration of thorium was determined to be at a level of about 100×10-9 g g-1, whereas the uranium concentration is in the range (300-700)×10-9 g g-1 for two types of specimen, one collected in Kojima port (Japan) and the other cultivated in an aquarium. A huge potassium concentration (up to 1.6 wt %) was determined in all samples. With high accuracy the abundances of the naturally occurring vanadium isotopes have been confirmed, thus excluding a possible selectivity by chemical reactions. As a result at present, vanadium metal extracted from Ascidia sydneiensis samea is impossible to use without further purification for the search of rare beta decay of 50V due to the high concentration of natural uranium, thorium and potassium., The possibility of purification in the form of vanadium(IV)-binding proteins using anion exchange column chromatography is discussed.

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O16 Thermodynamic Study on the Complexation of Dioxovanadium (V) with GLDA and D-(-)-Quinic Acid in Aqueous Solutions of Ionic Liquid K. Majlesi, S. Rezaienejad Department of Chemistry, Science and Research Branch, Islamic Azad University, Tehran, Iran. e-mail: [email protected]

Conventional chelates such as EDTA and sodium tripolyphosphate are based on aminopolycarboxylic acids and phosphates respectively. Unfortunately, because EDTA is not readily biodegradable and because phosphates can cause pollution, these conventional materials are often viewed as environmentally unfriendly. Tetrasodium DL-2-(2-carboxymethyl) nitrilotriacetic acid (GLDA) contains biobased carbon in contrast to EDTA whose carbon is fossil based. Because GLDA is highly soluble, it will be offered at a significantly higher concentration (approximately 30 percent higher molar aqueous concentration) than EDTA, reducing transport and packaging costs as well as packaging waste. Most significantly, GLDA is readily biodegradable and will reduce pollution by replacing phosphates in dishwashing detergents. All of the potentiometric and UV spectrophotometric measurements were perfomed at T = 298 K. Regarding our previous works about complexation and protonation of various metals, amino acids and aminopolycarboxylic acids1-4, protonation constants of GLDA and its complexation ability with dioxovanadium (V) were investigated at different ionic strengths of sodium chloride (0.1 < I (mol. dm-3) < 1.0 ) in order to obtain the ionic strength dependence patterns. The ionic strength dependence of protonation and stability constants were modeled by extended Debye-Hückel, specific ion interaction and parabolic equations to calculate the ionic strength dependence parameters. D-(-)-quinic acid is a biological substance with many applications in pharmacy and medicine especially for the treatment of influenza. The ionic strength trend in the current research is more or less similar to our previous works.1,4 Complexation of dioxovanadium (V) with D-(-)-quinic acid was also studied in different aqueous solutions of [bmim]BF4 at a fixed ionic strength and the results were interpreted on the basis of the Kamlet-Abboud-Taft (KAT) which showed that hydrogen bonding and polarizability are more important in comparison to the other available interactions in the solution.2 The results are in good agreement with literature values although there are only a few reports in the literature for the chemical equilibria in the aqueous solutions of ionic liquid. References 1. Majlesi, K. De Stefano, C. Lando, G. Sammartano, S. J. Chem. Thermodynamics. 2013, 67, 163-169. 2. Majlesi, K. Rezaienejad, S. J. Solution Chem. 2013, 42, 1305-1319. 3. Majlesi, K. Ghafari, N. J. Solution Chem. 2013, 42, 716-737. 4. Majlesi, K. Rezaienejad, S. Balali, S. J. Solution Chem. 2013, 42, 1729-1747.

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O17 Synthesis, Characterization and Reactivity of Oxidovanadium(IV) and Dioxidovanadium(V) Complexes and their Catalytic Activity M. R. Mauryaa, B. Sarkara, A. Kumarb,c, J. Costa Pessoab a

b

Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee-247667, India. Centro de Química Estrutural, Instituto Superior Técnico, Universidade Lisboa, Lisboa 1049-001, Portugal c Center for Nano & Material Science, Jain University, Bangalore– 562112, Karnataka, India. e-mail: [email protected]

The Schiff bases, {H3dfmp-(smdt)2} (I), {H3dfmp-(sbdt)2} (II) and {H3dfmp-(tsc)2}(III) were synthesized by condensing 2,6-diformyl-4-methylphenol (dfmp) and S-methyldithiocarbazate (smdt), S-benzyldithiocarbazate (sbdt) and thiosemicarbazone (tsc), respectively. The reaction of [VIVO(acac)2] with these ligands in methanol led to the formation of the oxidovanadium(IV) complexes [VIVO{Hdfmp-(smdt)2}(H2O)], [VIVO{Hdfmp-(sbdt)2}(H2O)], [VIVO{Hdfmp(tsc)2}(H2O)]. In methanolic solution and upon aerial oxidation in the presence of KOH all these oxidovanadium(IV) compounds oxidized to the corresponding dioxidovanadium(V) complexes. The isolated complexes are formulated as K[VVO2{Hdfmp-(smdt)2}], K[VVO2{Hdfmp-(sbdt)2}], K[VVO2{Hdfmp-(tsc)2}]. The corresponding Cs+ salts i.e. Cs[VVO2{Hdfmp-(smdt)2}], Cs[VVO2{Hdfmp-(sbdt)2}], Cs[VVO2{Hdfmp-(tsc)2}] were also prepared similarly in the presence of CsOH. All compounds are characterized in the solid state and in solution, namely by spectroscopic techniques (IR, UV-Vis, EPR, 1H and 51V NMR) and thermal studies. IR spectral data confirm the coordination of ligands through the azomethine nitrogen, sulphur and the phenolate oxygen atoms to the metal. These complexes show good catalytic activity towards the oxidation of benzyl alcohol in the presence of H2O2 as an oxidant. The main oxidation products are benzaldehyde and benzoic acid. Various parameters such as the amount of catalyst and oxidant, reaction time, reaction temperature, and solvent have been taken into consideration for the maximum oxidation of benzyl alcohol. Plausible intermediates involved in these catalytic processes were established by UV-Vis, EPR and 51V NMR spectroscopic studies.

R

H2O O S V H C N N N O N C S

O R +

M

O

H N

R

N

C

O

S

V

C N

R

N

S

R = SCH3 (1) M = K, R = SCH3 (4); M = Cs, R = SCH3 (7) R = SCH2C6H5 (2) M = K, R = SCH2C6H5 (5); M = Cs, R = SCH2C6H5 (8) R = NH2 (3) M = K, R = NH2 (6); M = Cs, R = NH2 (9) References 1. Maurya, M.R., Haldar, C., Kumar, A., Kuznetsov, M., Avecilla, F., Costa Pessoa, J. Dalton Trans. 2013, 42, 11941-11962. 2. Maurya, M.R., Kumar, A., Costa Pessoa, J. Coord. Chem. Rev. 2011, 255, 2315-2344. 3. Maurya, M.R., Khan, A., Azam, A., Kumar, A., S. Ranjan, Costa Pessoa, J. Eur. J. Inorg. Chem. 2009, 35 5377–5390. Acknowledgements: MRM, CH thank the Department of Science and Technology, the Government of India, New Delhi for financial support of the work. JCP and AK thank FEDER, Fundação para a Ciência e Tecnologia, the Portuguese NMR Network (IST-UTL Center), PEst-OE/QUI/UI0100/2013 and grant SFRH/BPD/90976/2012.

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O18 Structural Characterization of Vanadium(V) Hydrazido Complexes T. Moriuchia, K. Ikeuchia, T. Sakuramotoa, T. Hiraoa,b a

Department of Applied Chemistry, Graduate School of Engineering, Osaka University, Yamada-oka, Suita, Osaka 565-0871, Japan. b JST, ACT-C, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan. e-mail: [email protected]

The biochemical roles of vanadium have gained growing interest, which is related to the inslinomimetic ability of vanadium compounds and vanadium-dependent haloperoxidases. Although vanadium is known to be an essential constituent in certain nitrogenases, vanadium hydrazido complexes have attracted less attention. In previous papers, the substituent on the benzene ring of (arylimido)vanadium(V) compounds was demonstrated to affect the nature of the vanadium metal center and imido bond through π-conjugation.1 The substituent effect of the basal ligand in the vanadium(V) hydrazido complex has not been investigated so far. We herein report the deign of the vanadium(V) hydrazido complexes with tris(2-hydroxyphenyl)amine ligands to reveal the influence of the apical nitrogen and the substituent of the tris(2-hydroxyphenyl)amine ligand on the vanadium center.2 The coordination of the apical nitrogen to the vanadium center was performed to weaken the V-N multiple bond through the coordination from the apical nitrogen. The substituent at the 3-position of the tris(2-hydroxyphenyl)amine ligand was found to influence the electronic environment of the vanadium center directly.

References 1. a) Moriuchi, T.; Ishino, K.; Hirao, T. Chem. Lett. 2007, 1486-1487. (b) Moriuchi, T.; Beppu, T.; Ishino, K.; Nishina, M.; Hirao, T. Eur. J. Inorg. Chem. 2008, 12, 1969-1973. (c) Moriuchi, T.; Ishino, K.; Beppu, T.; Nishina, M.; Hirao, T. Inorg. Chem. 2008, 47, 7638-7643. (d) Moriuchi, T.; Nishina, M.; Hirao, T. Angew. Chem. Int. Ed. Engl. 2010, 49, 83-86. (e) Nishina, M.; Moriuchi, T.; Hirao, T. Dalton Trans. 2010, 39, 99369940. (f) Moriuchi, T.; Hirao, T. Coord. Chem. Rev. 2011, 255, 2371-2377. (g) Nishina, M.; Moriuchi, T.; Hirao, T. Bull. Chem. Soc. Jpn. 2012, 85, 606-612. 2. Moriuchi, T.; Ikeuchi, K.; Hirao, T. Dalton Trans. 2013, 42, 11824-11830.

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O19 Mirror symmetry breaking crystallization of M[VO2(N-salicylidene-isoleucinato)] ? L. Krivosudskýa, P. Schwendta, J. Šimuneka, R. Gyepesb a

Comenius University, Faculty of Natural Sciences, Department of Inorganic Chemistry, Mlynská dolina, 842 15, Bratislava, Slovakia. b J. Seley University, Pedagogical Faculty, Bratislavská cesta 3322, 945 01, Komárno, Slovakia. e-mail: [email protected]

Separation of one enantiomer from a racemic mixture is a serious challenge for stereochemistry. Thanks to diastereospecific formation of vanadium Schiff base complexes1-3 one has to omit certain theoretically possible stereoisomers and examples of isolation of non-racemic vanadium complexes from a racemate are known4. The crystallization of M[VO2(N-salicylidene-isoleucinato)] from a mixture possessing three stereogenic centers (Figure 1), the vanadium(V) atom, α and β-carbons of the amino acid site, surprisingly provides C-[VO2(N-salicyliden-L-isoleucinato)]− (1) as the only first product. A-[VO2(N-salicylidene-D-allo-isoleucinato)]− (2) is accessible after isolation of the preceding product as well. The absolute configurations of both stereoisomers were determined by electronic and vibrational circular dichroism and we have confirmed that the chirality at metal is in a close relation with configuration on the α-carbon of the amino acid site5,6. What is important, we did not obtain any sign of crystallization of complexes with D-isoleucine and L-allo-isoleucine. Figure 1 Schematic representation of the crystallization of M[VO2(N-salicylidene-isoleucinato)]− from a mixture of eight possible stereoisomers. While the ECD spectra of the two diastereoisomers are perfect mirror images, the VCD of 1 and 2 differs in a vibration at 1350 cm−1 which corresponds to C-H bending vibrations (CH group on β-carbon) coupled with wagging vibrations of – CH2– group.

References 1. Schulz, M., Debel, R., Görls, H., Plass, W., Westerhausen, M. Inorg. Chim. Acta 2011, 365, 349-355. 2. Bian, L., Li, L., Acta Cryst. Sect. E 2011, 67, 274. 3. Cao, Y.Z., Zhao, H.Y., Bai, F.Y., Xing, Y.H., Wei, D.M., Niu, S.Y., Shi, Z. Inorg. Chim. Acta 2011, 368, 223230. 4. Fulwood, R., Schmidt, H., Rehder, D. J. Chem. Soc., Chem. Commun. 1995, 1443-1444. 5. Downing, R. S., Urbach, F. L. J. Am. Chem. Soc. 1959 , 91, 5977-5983. 6. Kwiatkowski, E., Romanowski, G., Nowicki, W., Kwiatkowski, M. Polyhedron 2006,25, 2809-2814. Acknowledgements: This work was funded by the Grant Agency of the Ministry of Education of the Slovak Republic and Slovak Academy of Sciences VEGA project no. 1/0336/13 as well as by the Slovak Research and Development Agency (APVV-0510-12).

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O20 Vanadium catalyzed aerobic oxidative cleavage of lignin model substrates E. Amadio, B. Gjoka, R. Di Lorenzo, C. Zonta, G. Licini* Dipartimento Scienze Chimiche, Università di Padova, via Marzolo 1, 35131, Padova, Italy. e-mail: [email protected]

Lignocellulosic biomass is an important renewable feedstock for the production of chemicals, fuels and energy. With its unique structure, lignin can be regarded as the major aromatic resource of the bio-based economy and, therefore, a wide variety of aromatic compounds may result from its efficient valorization. However, due to its complex nature, inert resistance to chemical reactivity and the lack of suitable conversion technologies, selective lignin depolymerization to value-added products still remains a challenge.1 The development of robust catalysts that selectively target C-C bonds cleavage in lignin structure can be a key in overcoming the problem.2 Here we show that vanadium(V)-amino triphenolate complexes (TPAs-V) are good candidates to achieve such ambitious goals in a very active and selective manner under mild reaction conditions.

Figure 1. Oxidative C-C bond cleavage catalyzed by TPAs-V complexes.

Specifically, the reactivity of these complexes under catalytic aerobic conditions with different classes of model substrates such as diols, 1,2-hydroxyethers and more complex lignin substructures will be presented. References 1. Zakzeski, J.; Bruijnincx, P.; Jongerius, A. L.; Weckhuysen, B. M. Chem. Rev. 2010, 110, 3552. 2. a) Hanson, S. K.; Wu, R.; Pete Silks, L. A. Angew. Chem. Int. Ed. 2012, 51, 3410. b) Chan, J. M. W.; Bauer, S.; Sorek, H.; Sreekumar, S.; Wang, K.; Toste, F. D. ACS Catal. 2013, 3, 1369. Acknowledgements: This work was funded by Università di Padova, PRAT 2012 USE CARE, CPDA123307

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O21 Comparison of Co-precipitated and Impregnated Supported V2O5-WO3/TiO2 Catalysts for Selective Catalytic Reduction of NO with NH3 Y. He1,2, M. E. Ford1, I. E. Wachs1 1

Operando Molecular Spectroscopy & Catalysis Laboratory, Department of Chemical Engineering, Lehigh University, Bethlehem, PA, USA 18015 USA 2 College of Materials Science and Engineering, Chongqing University, Chongqing, 400030, China e-mail: [email protected] (I.E.W.)

Introduction Selective catalytic reduction (SCR) of nitrogen oxides (NOx) by ammonia is the state-of-the-art NOx emission control technology for stationary sources, including power plants and industrial boilers [1-3]. Supported V2O5-WO3/TiO2 catalysts, which show high catalytic activity and selectivity, thermal stability and resistance to sulfur poisoning, have long been accepted for commercial use [1-6]. These catalysts are typically prepared by impregnation of soluble vanadium and tungsten precursors onto a titania support. However, co-precipitation of titanyl sulfate with ammonium paratungstate has been reported to provide SCR catalysts with improved thermal stability [7]. To evaluate the performance of SCR catalysts prepared by both co-precipitation and impregnation, the structural, physico-chemical properties and reactivity of V2O5-WO3/TiO2 catalysts prepared by co-precipitation of TiO(OH)2 with ammonium tungstate were compared with those of the catalysts prepared by the conventional impregnation method. Results and Discussion In contrast to the impregnation method, in situ Raman spectroscopic characterization of the coprecipitation procedure results in the formation of two distinct WOx species on the TiO2 support: surface mono-oxo O=WO4 and a WO6 coordinated species trapped in the TiO2(anatase) bulk lattice. Both WOx species were formed whether or not vanadia is present. In situ Raman showed that the structure of vanadium oxide is unaffected by the synthesis method, VOx was present as mono-oxo surface O=VO3 species as well as polymeric vanadate species. In situ infrared spectroscopic studies revealed that both surface NH4+* and NH3* species chemisorbed on Brønsted and Lewis acid sites, respectively, are active during the NO-NH3 SCR reaction. Temperature programmed in situ IR spectroscopy demonstrated that the surface NH4+* species are more reactive than the surface NH3* species in the presence of gas phase O2, especially in the lower temperature region. References 1. Lietti, L.; Svachula, J.; Forzatti, P.; Busca, G.; Ramis, G.; Bregan, P. Catal. Today 1993, 17, 131-140. 2. Busca, G.; Lietti, L.; Ramis, G.; Berti, F. Appl. Catal., B 1998, 18, 1-36. 3. Forzatti, F.; Appl. Catal., A, 2001, 222, 221-236. 4. Wood, S.C. Chem. Eng. Prog. 1994, 90(I) 32-38. 5. Forzatti, P.; Lietti, L. Heterogeneous Chem. Rev. 1996, 3, 33-51. 6. Forzatti, P.; Nova, I.; Tronconi, E.; Kustov, A.; Thogersen, J.R. Catal. Today 2012, 184,153-159. 7. Kobayashi, M.; Miyoshi, K. Appl. Catal., B 2007, 72, 253-261.

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O22 Towards the structural and spectroscopic characterization of the of supported silica supported Vanadia-based catalysts D. Manganas1, M. Hävecker2, A. Knop Gericke2, A. Trunschke2, R. Schlögl2, S. De Beer1,3 and F. Neese1* 1)

Max-Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, D-45470 M lheim an der Ruhr, ermany 2) Inorganic Chemistry Department, Fritz−Haber−Institut der Max−Planck− esellschaft, Faradayweg 4−6, 14195 Berlin ermany e-mail: [email protected]

V2O5 is considered one of the most important compounds in metal oxide catalysis. Complementary research has focused on the geometric structure of Silica supported Vanadia-based catalysts and particularly how structure can be related to catalyticperformance1,2. In this front spectroscopy serves the purpose to establish relationship between structure and property. This concept involves Optical Absorption and resonance Raman spectroscopies as well as NEXAFS core electron spectroscopies. It is of no doubt that the materials science progress is directly associated to a thorough understanding of structure/spectra relationships. In this contribution we arrive in structure convergence by calculating the experimental resonance RAMAN and NEXAFS spectra for several V/Si candidate cluster molecules. The spectra are interpreted on the basis of DFT and ab initio quantum theoretical methods fully implemented in the ORCA large-scale computational package.3

References (1) Cavalleri, M.; Hermann, K.; Knop-Gericke, A.; Hävecker, M.; Herbert, R.; Hess, C.; Oestereich, A.; Döbler, J.; Schlögl, R. Journal of Catalysis 2009, 262, 215. (2) Gruene, P.; Wolfram, T.; Pelzer, K.; Schlögl, R.; Trunschke, A. Catalysis Today 2010, 157, 137. (3) Neese, F. Wiley Interdisciplinary Reviews: Computational Molecular Science 2012, 2, 73.

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O23 Atomic Structure and Special Reactivity Toward Alcohol Oxidation of Vanadia Nanoclusters on TiO2(110) L. Artigliaa, Stefano Agnolia, A. Vittadinib, A. Verdinic, A. Cossaroc, L. Floreanoc, G. Granozzia a

Dept. of Chemical Sciences, University of Padova, Padova, Italy. (10 pt) b ISTM-CNR, Via Marzolo 1, I-35131 Padova, Italy. c CNR-IOM, TASC National Laboratory, I-34149, Trieste, Italy. e-mail: [email protected]

Vanadium oxide (VOx) supported on other oxide surfaces (e.g. TiO2, Al2O3, etc) is currently employed in industry as an efficient and selective oxidation catalysts for several reactions. 1,2 Surface science studies based on well characterized model catalysts can provide a deep understanding of the elementary steps of such reactions. During the past years the VOx/TiO2-rutile(110) model system has been widely studied and characterized both from the structural and reactivity points of view.3 In particular, our group focused on the growth of VOx systems on TiO2(110), obtained by reactive evaporation of vanadium in an oxygen background: using such a procedure, both VOx ultrathin (UT) films and nanoclusters (NC, called dimers) with different oxidation states were obtained and their structure characterized by Angle Resolved (AR) X-ray Photoelectron Diffraction (XPD) and Scanning Tunneling Microscopy (STM).4 In the present work we will show new interesting insights on the structure and reactivity of VO x NCs deposited on TiO2(110).5 In particular, by means of AR-XPD and High Resolution (HR) X-ray Photoelectron Spectroscopy (XPS) obtained at the Elettra Synchrotron facility, combined with Density Functional (DF) calculations it was possible to confirm that VOx NCs grow aligned to the TiO2 [001] direction and the V oxidation state is 3+. Furthermore, methanol Temperature Programmed Desorption (TPD) experiments have demonstrated that oxidative dehydrogenation (ODH) reaction takes place at unprecedented low temperature (around 300 K). The mechanism proceed through dissociative adsorption of methanol, followed by hydride elimination from adsorbed methoxy groups, to yield formaldehyde and water with extremely high selectivity. References 1. Kroschwitz, J. I.; Howe-Grant, M. Encyclopedia of Chemical Technology, fourth ed., Wiley, New York, 1992. 2. Wachs. I.E., Dalton Transactions 2013, 42, 11762-11769. 3. Surnev, S., Ramsey, M.G., Netzer, F.P. Prog. Surf. Sci. 2003, 73, 117-165. 4. Della Negra, M., Sambi, M., Granozzi, G. Surf. Sci. 2000, 461, 118. Sambi, M., Della Negra, M., Granozzi, G. Surf. Sci. 2000, 470, L116. Sambi, M., Della Negra, M., Granozzi, G. Thin. Solid Films 2001, 400, 26. Agnoli, S., Sambi, M., Granozzi, G., Castellarin-Cudia, C., Surnev, S., Ramsey, M. G., Netzer, F.P. Surf. Sci. 2004, 562, 150. 5. Artiglia, L., Agnoli, S., Vittadini, A., Verdini, A., Cossaro, A., Floreano, L., Granozzi, G. J. Amer. Chem. Soc. 2013, 135, 17331-17338. Acknowledgements: This work has been funded by the Italian Ministry of Instruction, University and Research (MIUR) through the FIRB Project RBAP115AYN “Oxides at the nanoscale: multifunctionality and applications”, and through the fund “Programs of national relevance”(PRIN-2009). Calculations have been performed at the LICC (“Laboratorio interdipartimentale di chimica computazionale”) HPC facility of the Department of Chemical Sciences, University of Padua.

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O24 Coordination Chemistry of Macrocyclic Polyoxovandate Ligands for Lanthanide Complexes Y. Hayashi a

Department of Chemistry, Kanazawa University, Kakuma, Kanazawa, Japan. e-mail: [email protected]

Phosphoric acids condensed into polyphosphoric acids and the reaction is related to the support of life. Vanadate species also condensed into polyoxovanadates, and the dimer to pentamer of polyoxovanadates has been characterized in aqueous solution. In the course of our study to seek the condensation of polyoxovanadates, we discovered the self-condenstaion of VO3- species into a macrocyclic (VO3)nn- ligand which can support various kinds of 3d and 4d transition metal cations. The type of complexes formed was [M(VO3)n]n- where n is six to ten which afford some coordination spheres to incorporate various types of square-pyramidal to octahedral metal cations. In other words, the cyclic polyoxovanadates, (VO3)nn-, can be a macrocyclic ligand to transition elements with four to six coordination environments by changing ring number, n. The adjustments of the macrocyclic conformations allow the accommodation of a various cation. To expand the chemistry of an all-inorganic-macrocyclic polyoxovanadate ligand, we surveyed the reaction with lanthanide cations, whether it can form the complexes of the polyoxovanadates. We isolated all of the lanthanide series complexes except Pm. The early lanthanides with larger ionic radii require an eight-coordination sphere of a square-anti-prism. The ionic radius with a middle range, HoIII, has a seven-coordination sphere. The Ho complex shows a capped-prism environment. The later lanthanide elements with smaller ionic radii were fitted in a six-coordination mode. In summary, the early lanthanides have a larger coordination number, and the smaller ionic radius later lanthanides were in a six-coordination mode. Both of them have anti-prism-geometry in a squareanti-prism and in an octahedron which is also anti-prism. The anti-prism environments allow to accept the coordination from single macrocyclic polyoxovanadate ligands, (VO3)nn-, to support those cations, because of the shorter inter-prism distances. Instead, the regular-prism has the longer inter-distances, and it prohibits the coordination of the single macrocycle and, in the case of Ho, it has a sandwich structure of two macrocycles of V4 units. To elucidate the stability of the complexes, which is unprecedented, we evaluated those all-inorganic complexes by XAFS. The XAFS oscillations in the solids and in the solution states matched perfectly, and it suggests the structural integrity in acetonitrile solution. The detailed experimental results have been simulated by FEFF program and it shows good agreements between the crystal structure samples and solution samples in each of the complexes, thus it shows the cyclic polyoxovanadates, (VO3)nn-, function as a vanadium oxide ligand and incorporates lanthanide cations as well as 3d transition cations, just like organic ligands. References 1. Yoshihito, H., et. al., Eur. J. Inorg. Chem., 2013, 1876-1881. 2. Yoshihito, H., et. al., Inorg. Chem. 2012, 51, 784-793. Acknowledgements: This work was funded by Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan.

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O25

Vanadium(V/IV) complexes of thiosemicarbazones and semicarbazones T. Jakuscha, E.A. Enyedya, K. Kozmaa, C.R. Kowolc, N.V. Nagyd, D. Gambinoe, B.K. Kepplerc, T. Kissa,b a

Department of Inorganic and Analytical Chemistry, University of Szeged, Dóm tér 7. H-6720 Szeged, Hungary. b HAS-USZ Bioinorganic Chemistry Research Group, Dóm tér 7. H-6720 Szeged, Hungary. c Institute of Inorganic Chemistry, University of Vienna, Waehringer Str. 42, A-1090 Vienna, Austria. d Institute of Molecular Pharmacology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Pusztaszeri út 59-67, H-1025 Budapest, Hungary. e Cátedra de Química Inorgánica, Departamento Estrella Campos, Facultad de Química, Universidad de La República, 2124 Avenida General Flores, 11700 Montevideo, Uruguay. e-mail: [email protected]

Tiosemicarbazones (e.g. triapine®) are versatile compounds exhibiting anticancer, antimicrobial activity[1]. Their complexes also exert antitumor effect, which have higher antiproliferative effect than the ligands alone in many cases [2]. Our studies are focused on the most plausible species of the vanadium(IV,V) complexes emerging in the aqueous solutions at physiological pH and the effect of the substituents on the stability. The knowledge of the speciation and the most probable chemical forms of these complexes in aqueous solution is a mandatory prerequisite for understanding the mechanism of action and may be useful for the design of more effective and selective chemotherapeutics. PxTSC/APxTSC OH N

N N H

NH2

N H

N R1

R1

R1 = -H or -CH 3

N

N

S

PTSC

S

HO

STSC

N

OH

N

S

N H

NH 2

N H

R2

N

O N H

NH2

R 2 = -H or -Br

S N

N

OH

N R1

R1

SSC / Br-SSC

Triapine/APTSC

Only mono-ligandum complex formation were detected by pH-metry and EPR or 51V-NMR spectroscopic methods. At physiological pH the stability of the vanadium complexes were the highest in the case of PxTSC/APxTSC. However at biological concentration condition the complex formation is still not significant. References 1. J. Kolesar, R.C. Brundage, M. et al, Cancer Chemother. Pharmacol. 2011, 67, 393−400. 2. M.N.M. Milunovic, E.A. Enyedy, et al., Inorg. Chem. 2012, 51, 9309-9321. Acknowledgements: This work was supported by OTKA PD103905, TÁMOP 4.2.4. A/2-11-1-2012-0001 and the National Excellence Program (EA Enyedy).

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O26 Vanadium-based molecular assemblies as efficient catalytic systems for relevant oxidation processes N. Marinoa,b, G. Crucianic, J. Velasquez Ochoa d, F. Cavanid, R. P. Doyleb, G. De Munno.a a

Dipartimento di Chimica e Tecnologie Chimiche, Università della Calabria, via P. Bucci 14/c, 87036 Rende (CS), Italy. b Department of Chemistry, Syracuse University, Syracuse, NY 13244-4100, United States. c Dipartimento di Fisica e Scienze della Terra, Università di Ferrara, Via G. Saragat 1, 44122 Ferrara, Italy. d Dipartimento di Chimica Industriale ‘Toso Montanari’, Università di Bologna, Viale Risorgimento 4, 40136 Bologna, Italy. e-mail: [email protected]; [email protected]

Molecular vanadium-pyrophosphate (VPPi) assemblies seem like interesting species to investigate, since they can be regarded to as mimetic of the solid-state systems known as ‘VPO’ (VanadiumPhosphorous-Oxide), whose industrial relevance as well as extreme complexity is well acknowledged. The catalytic potential inherent in the solid state structure of vanadyl(IV)pyrophosphate, (VIVO)2P2O7 (Figure 1), generally accepted as the in-situ generated catalytic bulk phase for the selective oxidation of butane into maleic anhydride, is especially inspiring toward the idea of using discrete, VPPi coordination complexes for catalytic purposes. However, such molecular VPO systems have proven elusive so far. Recently, a unique example of VPPi complex was uncovered, namely {[(VO)bipy(H2O)]2(μ-P2O7)} (1),1 suggesting that mild vanadium-phosphate chemistry is indeed possible, and offering up a strategic platform for future investigations. Preliminary catalytic tests have already highlighted great potential for this species, and mechanistic studies are being currently undertaken. Herein we present the results of these studies, as well as the structural characterization of new phases through ab initio structure determination and Rietveld refinements based on high resolution synchrotron radiation XRPD. A new potential application for this class of understudied materials is also put forward.

Figure 1. Solid-state structure of vanadyl(IV)pyrophosphate. 2 References 1. Marino, N.; Hanson, S. K.; Müller, P.; Doyle, R. P. Inorg. Chem. 2012, 51 (19), 10077-10079. 2. Geupel, S. et al., Acta Cryst. 2002, C58, i9-i13. Acknowledgements: Thanks are due to the European Commission, FSE (Fondo Sociale Europeo) and Calabria Region for a Fellowship grant to N.M.

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O27 Correlating Compound Physical Properties with Anti-Diabetic Effects; Dipicolinatooxovanadium(V) Substituted Compounds D. C. Crans, A. M. Trujillo, J. A. Burke Dept. Chemistry, Colorado State University, Fort Collins, Colorado, USA. e-mail: [email protected]

Dipicolinatooxovanadium(V) prepared from the ligand 2,6-pyridinedicarboxylic acid abbreviated dipicolinate, is a known antidiabetic compound and in vitro studies have recently shown that their antidiabetic properties correlate with their absorption into model membrane systems.1 We investigated the effects of substituents in the 4-position (H, OH, Cl, NH2 and NO2) on the O-D stretch in a nanosized water pool in a reverse micellar model system and the 1H and 51V NMR chemical shifts of ligand and dipicolinatooxovanadium(V) coordination complexes in this same model system. The O-D shift is generally affected when the solute reside in the waterpool or near the interface, whereas no change is observed if the solute penetrate the interface. The studies show that the penetration is greatest in the following order H >> OH, Cl > NH2 >NO2 with the dipicolinatooxovanadium(V) being completely penetrated up into the interface3, and the 4-nitrodipicolinatooxovanadium(V) being mainly in the water pool. To obtain additional information the chemical shift changes were also analyzed using linear free energy relationships and Hammett correlation plots.2 Plotting the 51V NMR chemical shifts (X-H) of the vanadium-dipicolinate dipicolinatooxovanadium(V) complexes as a function of the Hammett constant, a linear correlation resulted with an r2 of 88%. These findings show that NMR chemical shifts can be used to produce linear free energy relationships in these coordination compounds. In addition, the chemical shift differences between the aqueous and reverse micelle systems (RMX-X) were plotted and a linear relationship was observed. Together these studies show that all the active antidiabetic dipicolinatooxovanadium(V) compounds are found to associate with the model systems interfaces and although significant changes are found in their electronic properties this does not impact their antidiabetic properties. References 1. Sostarecz, A.G., Gaidamauskas, E., Distin, S. Bonetti, S. J.Levinger, N. E. and Crans, D. C.. Chemistry – A European Journal 2013, in press. 2. Hammett, L. P. J. Am. Chem. Soc., 1935, 59(1), 96 – 103. 3. Crans, D.C., Rithner, C. D., Baruah, B., Gourley, B. L., Levinger, N.E. J. Am. Chem. Soc. 2006, 128, 44374445.

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O28 Vanadium metallodrugs: from the design to the anticancer biology a

A. Salifogloua Department of Chemical Engineering, School of Engineering, Aristotle University of Thessaloniki, Thessaloniki 54124. e-mail: [email protected]

Metallodrugs are currently used as anticancer drugs and bear strong merit in the fight against cancer. One of the metals emerging as a potential anticancer agent is vanadium, reflecting an element with a plethora of distinct properties in structural diversity and chemical reactivity in the abiotic and biological world. In such a setting, the development of effective, atoxic and specific vanadodrugs to combat cancer sets the tone for the design, synthesis and biological investigation of anticarcinogenic potency in specific forms of cancer. To this end, ternary vanadium systems containing hydrogen peroxide and zwitterionic moieties were investigated in our labs in aqueous media. The design of such ternary systems employing physiological substrates led to the aqueous structural speciation, synthetic chemistry, isolation and physicochemical characterization of a family of such species, subsequently characterized both in the solid state and in solution. 1 Key to the structural identity of these new species was a) the presence of mononuclear as well as dinuclear V(V) species containing peroxide and betaines ligands, b) diperoxido moieties bound to the V(V) centers, and c) zwitterionic betaines bound to one of the V(V) centers yet retaining their bipolar electrostatic character. The increased stability of such species compared to conventional V(V) binary and ternary species previously synthesized and characterized was the basis of their ensuing employment in the exploration of the biological activity as anticarcinogenic agents. The biological interactions of select members of that family of vanadoforms with the well-known oncogenic target H-ras, inherent to a number of cancers, have been probed in a number of cancer cell lines (MCF7, A549 cells) in vitro and presented a wealth of information linking vanadium with its biological activity against cancer cell processes. Undoubtedly, the distinctly different forms of ternary vanadium species in cellular media influence heavily the chemical reactivity of vanadium and hence its anticarcinogenic activity. It appears that ternary vanadium acts through suppression of H-ras and MMP-2 expression by increasing Reactive Oxygen Species-mediated apoptosis in cancer cells, thereby leading to the cellular demise in both cancer cell lines each of distinct physiological profile.2 Therefore, signaling pathways, explored through the exposure of the cancer cells to vanadium, appear to carry significant information linking the metal with the chemical action responsible for the emerging anticarcinogenic potential. Collectively, the synthetic and molecular biological approaches used in this work formulate the framework of interactions between the new vanadoforms with genetic loci linked to cancer processes and set the basis for further development of high specificity metallotherapeutics. References 1. Gabriel, C.; Kioseoglou, E.; Venetis, J.; Psycharis, V.; Raptopoulou, C.P.; Terzis, A.; Voyiatzis, G.; Bertmer, M.; Mateescu, C.; Salifoglou, A. Inorg Chem. 2012, 51, 6056. 2. Petanidis, S.; Kioseoglou, E.; Hadzopoulou-Cladaras, M.; Salifoglou, A. Cancer Lett. 2013, 335, 387.

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POSTER PRESENTATIONS

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P1 New mandelato complexes of vanadium(V) P. Antal a, P. Schwendta, J. Tatierskya, R. Gyepesb,c, Z. Žákd a

Department of Inorganic Chemistry, Faculty of Natural Sciences, ComeniusUniversity, Bratislava, SlovakRepublic. b J. SelyeUniversity, Pedagogical Faculty, Komárno, SlovakRepublic. c J. Heyrovsky Institute of Physical Chemistry of the AS CR, Prague, Czech Republic d Department of Inorganic Chemistry, Faculty of Natural Sciences, Masaryk University, Brno, CzechRepublic. e-mail: [email protected]

The interactions of racemic chiral cations and anions in solution may result in crystallization of a racemic compound, racemic conglomerate or chiral non-racemic compound [1]. Three new mandelato complexes of vanadium(V) were prepared and characterized by spectral methods and X-ray structural analysis. (N(CH3)4)4[V2O4((R)-mand)2][V2O4((S)-mand)2]·CH3OH·H2O (1) was prepared by crystallization from the NH4VO3–N(CH3)4OH–rac-H2mand–H2O–EtOH (H2mand = mandelic acid) system. 1 is the first dioxido mandelato complex of vanadium(V) and a typical racemic compound. [Cu(bpy)2Cl]2[V2O2(O2)2((S)-mand)2]·H2O (2) and Δ-[Fe(bpy)3][V3O6(OH)((S)-mand)2]·2H2O (3) were prepared by crystallization from the KVO3–H2O2–H2(S)-mand–MX–bpy–H2O–CH3CN (MX = CuCl2·2H2O or FeSO4·7H2O); bpy = 2,2-bipyridine) systems. Compound 2 is chiral due to the presence of only one enantiomer of mandelato ligand in the anion. Unique chiral trinuclear anion in 3 (Fig. 1) enforced Δ configurations of all [Fe(bpy)3]2+ cations through the process of molecular recognition.

Figure 1: Structure of the [V3O6(OH)((S)-mand)2]2– anion in crystal structure of 3. References 3. Antal, P.; Tatiersky J.; Schwendt, P.; Žák, Z., Gyepes, R. J. Mol. Struct. 2013, 1032, 240-245. Acknowledgements: This work was funded by the Ministry of Education of Slovak Republik (VEGA 1/0336/13).

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P2 Haloperoxidation Reactivity of V(V), Mo(VI) and W(VI) Amine Trisphenolate Complexes E. Badettia, F. Romanoa, L. Marchiòb, C. Zontaa, G. Licinia a

Dipartimento di Scienze Chimiche, Università di Padova, Via Marzolo 1,35131 Padova, Italy Dipartimento di Chimica, Università di Parma, Viale delle Scienze 17/A, 43123 Parma, Italy e-mail: [email protected]

b

Triphenolamines are highly modular tetradentate molecules that effectively coordinate to transition metals and main group elements with podand topology. The metal complexes, especially Ti(IV) and V(V), have been found to be effective catalyst in polymerization reactions and oxygen transfer processes. More recently we started to explore the corresponding Mo(VI) and W(VI) complexes.1

These neutral complexes are obtained by reaction of triphenolamines with vanadium, molybdenum and tungsten salts. In this contribution we will discuss about the synthesis, characterisation and catalytic properties in oxygen transfer reactions of these complexes with special regards to haloperoxidation activity.2 References 1. G. Licini, M. Mba, C. Zonta, Dalton Trans,2009, 27, 5265-5277. M. Mba, L. J. Prins, G. Licini Org. Lett.2007, 9, 21-24. C. Zonta, E. Cazzola, M. Mba, G. Licini Adv. Synth. Cat. 2008, 350, 2503-2506. M. Mba, M. Pontini, S. Lovat, C. Zonta, G. Bernardinelli, P.E. Kundig, G. Licini Inorg. Chem. 2008, 47,86168618. 2. F. Romano, A. Linden, M. Mba, C. Zonta, G. Licini, Adv. Synth. Catal. 2010, 352, 2937 – 2942. Acknowledgements: This work was funded by Università di Padova, Assegni di Ricerca Senior.

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P3 One-pot Glycerol Oxidehydration to Acrylic Acid on Hexagonal-TungstenBronze-Derived Structures as Multifunctional Catalysts

a

C. Bandinellia, A. Chieregatoa,b, M. D. Sorianob, F. Basileb, S. Zamorab, P. Concepciònb, G. Pugliaa, F. Cavania, J. M. Lòpez Nietob

Dipartimento di Chimica Industriale “Toso Montanari”, ALMA MATER STUDIORUM Università di Bologna, Viale Risorgimento 4, Bologna, 40136 ,Italy. b Instituto de Tecnología Química, UPV-CSIC, Campus de la Universidad Politécnica de Valencia, Avda. Los Naranjos s/n;46022, Valencia, Spain. e-mail: [email protected]

Due to the large surplus of glycerol formed as a by-product of the biodiesel production, in the last decades many efforts have been made to find new applications; indeed, a large number of selective processes for converting glycerol into added-value products have been proposed1. One of the most studied routes is the transformation of glycerol into acrolein, whereas only recently more attention has been paid to its direct transformation into acrylic acid2. Glycerol gas-phase oxidehydration to acrylic acid represents instead an interesting option, as it allows performing the direct transformation of glycerol into the acid monomer by means of a single-step process. Suitable catalysts require bi-functional properties: (i) acid sites, for the dehydration of glycerol into acrolein, and (ii) redox properties, for the oxidation of acrolein into acrylic acid. The multifunctional catalysts developed by our group since 2011, consist in some of the best performing catalysts for the one-pot glycerol oxidehydration into acrylic acid,2,3,4 that exhibit yields into the acid monomer as high as 51%. The catalysts investigated consist of multi-component mixed oxides: W-V-O, W-Mo-O, W-V-Nb-O and W-Mo-V-O. They were prepared by means of hydrothermal synthesis and characterized with various techniques (XPS, RAMAN, FTIR, SEM, XRD, N2-adsorption, NH3-TPD and TPR analysis).Reactivity experiments for glycerol transformation were carried out in a bench-scale plant equipped with a continuous flow quartz reactor, operating at atmospheric pressure. These materials are mainly composed of hexagonal-tungsten-bronze structures and present both acid and redox features:the presence of molybdenum and vanadium into the oxide frame allowed us to tune the redox features of the catalysts, whereas niobium optimized the acid properties. All in all, these materials allowed us to draw important conclusion on the rate-determining step of glycerol oxidehydration process. Moreover, all of them showed high selectivity into both acrylic acid and acrolein, along with outstanding productivity values, much higher than those so far reported in literature4. Finally, W-Mo-V-O catalysts gave stable yields into acrylic acid in a wide range of temperature, the latter being an important step forward for the industrial applicability of the glycerol oxidehydration reaction. References 1. Pagliaro, M. et al.,Angew. Chem., Int. Ed. 2007, 46, 4434-4440. 2. Soriano, M. D. et al.,Green Chem. 2011, 13, 2954-2962. 3. Chieregato, A. et al.,Catal. Today, 2012, 197, 58-65. 4. Chieregato. A. et al.,Appl. Catal. B: Env.,2014, 150– 151, 37– 46.

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P4 Separation of Vanadium Compounds by HPLC; Reverse phase, Normal phase, Ion pair, Cation and Anion Exchange matrices and vanadium speciation I. Boukhobzaa and D. C. Cransb a

b

Department of Interdisciplinary Studies, Zayed University, Dubai ,UAE Department of Chemistry, Colorado State University, Fort Collins, CO,USA e-mail: Iman [email protected]

The increasing demands for the characterization and determination of vanadium compounds and their activity requires access to several methods of detection. The presence of vanadate and vanadium compounds in many environmental, biological and clinical matrices represent diverse samples that needs analyses. The analysis of vanadium compounds is non-trivial because of the vanadium coordination chemistry that result in speciation and subsequent chemistry depending on the method of analysis. Indeed, different vanadium compounds will form during the speciation process. Many studies have used a range of methods for the characterization and demonstrate speciation of these materials. Among these methods, high performance liquid chromatography (HPLC) has successfully been used in the separation and determination of a large number of vanadium compounds. Furthermore, the reversed phase HPLC has frequently been used detection and speciation of vanadium compound. However other HPLC modes such as normal phase, anion-exchange, cation-exchange, ion-pair and micellar methods have also been used to separate a selected vanadium compounds. In the following poster, we will present a comprehensive review that addresses the speciation and analysis of vanadate and vanadium compounds in different sample matrices. We will compare various HPLC modes including sample preparation, chelating reagents, mobile phase and detection methods. The comparison will allow us to identify the best analytical HPLC method for an effective separation of vanadium compounds and how such processes impact the speciation of the vanadium compounds

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P5

VO(acac)2-phosphate Complex as Species Responsible for the Efficient Nuclease Activity of VIVO(acac)2 N. Butenkoa,b, J.P. Pinheiroc, J.P. Da Silvaa, J. Costa Pessoab, I. Cavacoa,b a

Universidade do Algarve, Departamento de Química e Farmácia, Faculdade de Ciência e Tecnologia, Campus de Gambelas, 8005-139 Faro, Portugal b Instituto Superior Técnico, Centro de Química Estrutural, TU Lisbon, Av Rovisco Pais, 1049-001 Lisboa Portugal c Universidade do Algarve, Centro de Biomedicina Molecular e Estrutural, Campus de Gambelas, 8005-139 Faro, Portugal e-mail: [email protected], [email protected]

Metal coordination compounds as therapeutics for different medical applications are currently one of the most demanding subjects in the biochemical research. More and more metal complexes are recognized as effective drugs in diseases such as cancer, diabetes, HIV, and malaria. Metallotherapeutic interest in vanadium rose as early as 1899, when it was orally given as a drug to diabetic individuals. Nowadays vanadium compounds are widely studied for their antidiabetic, anticancer properties, as well as against parasitic diseases. A different and equally important motivation to study vanadium compounds comes from predicting possible undesirable DNA damage following their use as therapeutic agents. We studied the DNA cleavage by VIVO(acac)2, a compound that was found to have insulinenhancing activity, in order to predict a possible DNA damage, that vanadium compounds could cause when tested as potential antidiabetic agents. VIVO(acac)2 and derivatives have demonstrated a remarkable DNA cleavage activity [1] with an oxidative mechanism mediated by reactive oxygen species (ROS), most probably hydroxyl radicals. We have observed that the generation of ROS in aqueous solution by these complexes is potentiated under phosphate buffer. The species responsible for this activity are probably mixed complexes of VO(acac)2 and phosphate which are formed only at very high metal:phosphate ratios (~1:1000). The redox behaviour of such species observed by cyclic and square wave voltammetry is very flexible, unlike of other V(IV) and V(V) species typically formed in solution. The presence of a dimeric species formulated as (VIVO)(VVO)(acac)2(PO4) was confirmed by ESI-MS. The study shows that the dissolution of VO(acac)2-type complexes in biological media will generate species that, even though formed at low concentrations and extremely difficult to detect and identify by most techniques, have a reversible redox behaviour which will have an important role in biological systems. These species strongly increase the oxidative stress in the biological cell causing undesirable effects such as DNA cleavage. References 1. Butenko, N.; Tomaz, A.I.; Nouri, O.; Escribano, E.; Moreno, V.; Gama, S.; Ribeiro, V.; Telo, J.P.; Costa Pesssoa, J.; Cavaco, I. J. Inorg. Biochem. 2009, 103, 622-632. Acknowledgements. The authors acknowledge the support from POCI 2010, FEDER. N. Butenko is grateful to Fundação para a Ciência e Tecnologia for the PhD grant (SFRH / BD / 69444 / 2010).

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P6 How Important is the Trigonal Bipyramidal Geometry for Phosphatase Inhibitors? D. C. Cransa, C. McLauchlanb a

Department of Chemistry, Colorado State University, Fort Collins,CO 80523 USA b Department of Chemistry, Illinois State University, Normal, IL 61790 USA e-mail: [email protected]

The five-coordinate geometry is particularly desirable for vanadium compounds used as phosphorylase inhibitors because of the five-coordinate transition state structure for phosphate esters. In the following poster we have carried out a structural analysis comparing the known structural characterized vanadium compounds with four oxygen ligands and one other ligand, which is either sulfur, halogen, or carbon; i.e. the compound described by a VO4X coordination sphere where X is neither nitrogen or oxygen. There are two limiting geometries in a five-coordinate system, the trigonal bipyramidal and square planar structure, which can be described by the interligand angles and summarized using the parameter .1 In a simple, ideal square pyramidal geometry, the two basal angles  and  are  =  = 180°, which gives the value ( – )/60 = 0 for square pyramidal. In contrast for the ideal trigonal bipyramidal geometry the  and angles have the  = (180 – 120)/60, which is unity. Therefore, any structure that is neither ideal square pyramidal or trigonal bipyramidal will have a  value between 0 and 1. We have analyzed the reported structures using this simple index parameter to characterize each of these geometries of the complexes and compared them to some of the well-known inhibitors. The comparison allows us to begin to address the question how ideal trigonal bipyramidal a vanadium compound must be to be an effective inhibitor. References 1. Addison, A. W.; Rao, T. N.; Reedjik, J.; van Rijn, J.; Verschoor, G.C. J. Chem. Soc., Dalton Trans.1984, 1349-1356.

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P7 Investigation of vanadium (IV) or (V) compounds towards the formation of reactive oxygen species in biomimetic media A. Dieronitoua, C. Drouzab and A. Keramidasa a

University of Cyprus, Department of Chemistry, 1678 Nicosia, Cyprus Cyprus University of Technology, Department of Agriculture Sciences, Biotechnology and Food Science, Lemesos, 3036 Cyprus e-mail: [email protected]

b

Vanadium is a transition metal which acts as an oxidant agent in the presence of oxygen. Vanadium activates the oxygen and lead to the formation of reactive oxygen species. Reactive oxygen species can cause oxidative stress to the membrane cells and lead to many chronic and degenerative diseases such as cancer, Parkinson, Alzheimer, aging. In our study we investigate the formation of reactive oxygen species in vegetable oils in the present or absence of amphiphilic vanadium compounds which were synthesized in our laboratory. We have selected vegetables oils as our model system because their composition makes them excellent biomimetic media of the membrane cells. In our investigation we used different methods, such as DPPH inhibition measurements, TBAR (thiobarbituric acid reactive substances), PV (peroxide value), NMR and cyclic voltammetry, in order to measure and characterize the produced reactive oxygen species (ROS). Correlation of the data show that the interactions of the amphiphilic Vanadium(IV/V) compounds with the phenolic components of the olive oil results in the reduction of dioxygen and in the formation of peroxy radicals. References 1. Randal J. Keller, Raghubir P. Sharma, Thomas A. Grover and Lawrence H. Piette, Archives of Biochemistry and Biophysics, Vol. 265, No. 2, 1988, pp. 524-533. Acknowledgements: The authors acknowledge financial supporters: This work has been co-funded by the European Regional Development Fund and the Republic of Cyprus through the Research Promotion Foundation (Infrastructure Project: ANABAΘMIΣH/0308/32).

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P8 Towards Water Soluble Vanadium(V) Amine Triphenolate Catalysts R. Di Lorenzoa, E. Amadioa, A. Mroczeka, C. A. Angulo-Pachónb, B. Escuderb*, C. Zontaa, G. Licinia* a

b

Department of Chemical Sciences, Università di Padova, Via Marzolo 1,35131, Padova, Italy. Department of Inorganic and Organic Chemistry, Universitat Jaume I,Av. Sos Balnat, s/n, 12071, Castelló de la Plana, Spain. e-mail: [email protected]

The development of water soluble catalytic systems represents a great interest nowadays, as it can offer the opportunity to perform organic transformations in a green and cheap solvent. In this context, we want to exploit our experience in synthesizing amine triphenolate (TPA) complexes1 for the realization of water soluble and hydrogel-supported catalysts. In particular, the aim of the present work is to address this challenge by developing a robust and efficient TPA functionalization strategy, which includes the TPA skeleton decoration through a three fold-para formylation of the phenol moieties and further functionalization via oxime bonds in order to introduce ion-tagged moieties or hydro-gelator residues.2

The formation of the corresponding V(V) complexes gives rise to nanostructured systems, whose catalytic activity towards oxidation reaction is currently under study. References 1. G. Licini, M. Mba, C. Zonta Dalton Trans., 2009, 5265. 2. F. Rodríguez-Llansola, J. F. Miravet, B. Escuder Chem. Commun., 2009, 7303.

Acknowledegments: We acknowledge COST Action CM1005 (RDL STSM) and University of Padova (PRAT 2012, CPDA123307) for financial support.

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P9 Diastereocontrol by Alkene Configuration in Vanadium(V)-catalyzed Oxidative 4-Pentenol Cyclization M. Dönges, J. Hartung TU Kaiserslautern, Erwin-Schrödinger-Straße 54, 67663 Kaiserslautern, Germany. e-mail: [email protected]

1-Phenyl-substituted 4-pentenols furnish 2-(tetrahydrofuran-2-yl)-2-propanols as major and tetrahydropyran-3-ols as minor products when oxidized by tert-butyl hydroperoxide (TBHP) and a lewis-acidic vanadium(V)-catalyst VOL(OEt) (H2L = N-salicylideneaminophenol or cis-2,6-bis(diphenylmethanol)piperidine) either in an atmosphere of nitrogen or in the presence of cyclohexa1,4-diene (CHD). The substitution pattern of the 4-pentenol double bond controls the stereoselectivity of the formed products. Terminal dimethyl-substituted (prenyl type) 4-pentenols afford under such conditions 2,5-cis-derivatives of 2-(tetrahydrofuran-2-yl)-2-propanols, while oxidation of terminal unsubstituted 4-pentenols proceeds 2,5-trans-selectively. previous work: H

O

H OH

R=H [O]

R = CH3 [O]

OH

H

O

H OH

R major cis:trans ~ 40:60

major cis:trans > 96:4

R

current study: H Ph

O

H OH

=H [O]

Ph

OH

=H [O]

major cis:trans ~ 25:75

H Ph

O

H OH

major [O] = TBHP / VOL(OEt) / CHCl3 / 20°C / N2

cis:trans ~ 87:13

In order to clarify the experimentally determined diastereodivergence in oxidative 4-pentenol cyclization caused by substitution at the -bond, we prepared (E)- and (Z)-alkenols and oxidized the substrates by TBHP catalyzed by VOL(OEt) (vide supra). Oxidation of (E)-alkenols furnish trans2,5-substituted (tetrahydrofuran-2-yl)-alkan-2-ols under such conditions showing relative unlikeconfiguration for the side chain stereocenter and the proximate tetrahydrofuran carbon. (Z)Alkenols provide cis-2,5-substituted (tetrahydrofuran-2-yl)-alkan-2-ols showing like-configuration for the stereocenter in the side chain. From such information we concluded that the (Z)-substituent is the principal stereoinductor in oxidative 5-exo-cyclization of prenyl type 4-pentenols, presumably for steric reasons. References 1. Hartung J., Drees S., Greb M., Schmidt P., Svoboda I., Fuess H., Murso A., Stalke D., Eur. J. Org. Chem., 2003,13, 2388-2408. 2. Amberg M., Dönges M., Stapf G., Hartung J., Tetrahedron, accepted for publication. Acknowledgements: The authors thank NanoKat for financial support.

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P10 Synthesis and characterization of amphiphilic V(IV/V) complexes as paramagnetic probes for applications on edible oils C. Drouzaa and A. Dieronitoub a

Cyprus University of Technology, Department of Agriculture Sciences, Biotechnology and Food Science, Lemesos, Cyprus b University of Cyprus, Department of Chemistry, Nicosia, Cyprus e-mail: [email protected]

Vanadium ions can facilitate the formation of free radicals producing reactive oxygen species and induce lipid peroxidation, some of them active in EPR spectroscopy. Lipid peroxidation consists a redox process of major importance in the processing and the storage of food, especially fats and oils. EPR spectroscopy has been utilized for monitoring the interaction of vanadium ions with molecular oxygen/phenolics towards the lipid peroxidation. The development of new methodologies utilizing fast and nondestructive spectroscopic techniques, such as EPR spectroscopy, in food analysis and characterization has attracted great interest. Despite the fact that EPR is a very sensitive and quantifying technique, up to date the number of applications developed in Food Science is limited. The applications until today are oriented to the determination of the antioxidant activity of foods and the measurement of radical damage after γ-irradiation applied for conservation of food. The absence of naturally spin probes in foods makes difficult the utilization of the EPR spectroscopy, since EPR requires the presence of unpaired electrons. Our group has prepared new amphiphilic vanadium compounds compatible with the edible oils in order to investigate the mechanism of generation of reactive oxygen species and their interaction with the phenolic components contained in the oils. . EPR is used to monitor the formation and deterioration of the -tocopheryl radical. The dynamics of this reaction is directly dependent on both the quantity of -tocopherol and the quantity and the type of the rest of the phenols in olive oils.

References 1. Drouza, C., Keramidas, A. D. Inorg. Chem., 2008, 47, 7211-7224. 2. Ottaviani M. F,Spallaci M., Cangiotti M., Bacchiocca M.,‡ and P. Ninfali, J. Agric. Food Chem. 2001, 49, 3691-3696. Acknowledgements: The authors acknowledge financial supporters: This work has been co-funded by the European Regional Development Fund and the Republic of Cyprus through the Research Promotion Foundation (Infrastructure Project: ANABAΘMIΣH/0308/32).

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P11 Anticancer drug development. Effects of a complex of oxidovanadium(IV) with silibinin in osteoblast cell lines. Relationship with the inhibition of topoisomerase IB I.E. León1, V. Porro2, A.L. Di Virgilio1, M. Bollati-Fogolin2, S. Castelli3, A. Desideri3, and S.B. Etcheverry1 1

Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina, 2 Instituto Pasteur, Montevideo, Uruguay, 3 Universidad de Roma 2,Roma, Italy e-mail: [email protected]

The family of polyphenolic flavonoids as well as vanadium compounds present interesting pharmacological actions. In this work we report the biological effects of a complex of vanadyl(IV) with Silibinin Na2[VO(silibinin)2].6H2O (VOsilibinin) on MG-63 human osteosarcoma derived cell line and the results were compared with previous ones from our laboratory on two murine osteoblastic cell lines: MC3T3-E1 and UMR106. The effects on cell viability (crystal violet bioassay, MTT bioassay and neutral red uptake) and on the genotoxicity (micronucleus and comet assay) Showed that VOsilibinin caused an inhibitory effect on cell viability in a concentrationdependent manner (p < 0.01. The antiproliferative action of the complex was much stronger than that of the free flavonoid (p