Stabilization of tetrameric metavanadate ion by tris(1,10-phenanthroline)cobalt(III): synthesis, spectroscopic, and X-ray structural study of [Co(phen)3]3(V4O12)2Cl • 27H2O

A new complex salt of composition [Co(phen)3]3(V4O12)2Cl 27H2O (phen = 1,10-phenanthroline and [V4O12]4- = tetrameric metavanadate, dodecaoxotetravanadate ion) was synthesized by the reaction of appropriate salts in aqueous medium. The complex salt has been characterized by elemental analyses, thermogravimetric analysis, cyclic voltammetry, FT-IR, and UV-Vis spectroscopies, solubility product and conductance measurements. Single crystal X-ray structure determination revealed ionic structure consisting of three complex cations, [Co(phen)3]3+, two [V4O12]4- anions, one chloride and 27 lattice water molecules. Detailed structural and spectroscopic analyses of [Co(phen)3]3(V4O12)2Cl 27H2O showed that the large anion is stabilized by large cationic metal complex as there is preferred shape compatibility that leads to a large number of lattice-stabilizing non-covalent interactions.