Synthesis and characterization of vanadium compounds containing pyridine and pyrazine ligands with carboxylic acid groups

Synthesis and Characterization of VanadiumCompounds Containing Pyridine andPyrazine Ligands with Carboxylic Acid GroupsBihter ŞAŞMAZAfyon Kocatepe UniversityGraduate School of Natural and Applied SciencesInorganic ChemistrySupervisor: Assoc. Prof. Sabri CEVİKIn this study, pyridine and pyrazine ligands containing carboxylate group and/orinorganic polyoxo groups tried to incorporate with vanadium to obtain novelpolyoxometallate, molecular coordination an/or inorganic solid-state and/or molecularcompounds. Multifunctional rigid type carboxylate ligands as tethers for theconstruction of solid phases were used to obtain diverse and unusual topologies.Selected inorganic and organic polyoxo ligands in this study were sulfate, 2,5-Pyridinedicarboxylic acid, 2,6- Pyridinedicarboxylic acid and 2,3-Pyrazinedicarboxylicacid to reach the purposes.The successful reactions gave one inorganic-organic hybrid, one V/O/SO4 molecularand two molecular coordination compounds. Among these compounds,[V2O2(SO4)2(H2O)6], [V(C5H4(COO)N)(C5H3(COO)2N)(H2O)2]?H2O and [VO(C4H3(COO)N2)2(H2O)]?2H2O have been fully characterized including single crystal X-raystructural analysis and infrared spectroscopy (FTIR), manganometric titration, roomtemperature magnetic susceptibility measurements, elemental analysis (CHNSanalysis) and Thermogravimetric Analysis (TGA). The last compound was proposedwith basic formula as C7H7NO6V and characterized by using characterization methodsmentioned above but excluding single crystal X-ray structural analysis due to nothaving enough sized single crystal.In this study, conventional reflux and hydrothermal/solvothermal synthetic methodshave been applied. The hydrothermal synthetic methods were successful to preparenovel reduced oxovanadium phases and incorporating polyoxo ligands.2009, 60 ppKeywords: Vanadium, Oxovanadyl, Oxovanadium, Hydrothermal Synthesis,Characterization, Sulphate, Sulfate, Pyridinedicarboxylic acid, Pyrazinedicarboxylicacid, Pyridinecarboxylic acid, Piconilic acid.