A new single pot synthesis of μ-bis(oxido)bis{oxidovanadium(V)} dipicolinato complex with 2-aminopyridinium as counter cation: Spectroscopic, structural, catalytic and theoretical studies

A new dinuclear, μ-bis(oxido)bis{oxidovanadium(V)} dipicolinato complex, [apyH]2[{VOL}2(μ-O)2].2H2O [1], [L = 2,6-dipicolinate; apyH = 2-aminopyridinium] has been synthesized by two different preparative methods using a single pot synthesis involving [VO(acac)2] or VOSO4.3H2O, and 2,6-dicarboxamido-2-pyridylpyridine (H2dcapp). The ligand H2dcapp undergoes vanadium-induced amide hydrolysis to yield the complex 1. The complex has been characterized by elemental analysis, electronic absorption, IR, 1H NMR, and finally by X-ray crystallography. The electronic absorption bands of 1 have been assigned with the help of TD-DFT calculations. The complex 1 forms a two-dimensional grid along [001] plane, which on combination with one-dimensional polymeric chains along the [100] direction, forms three-dimensional supramolecular framework. Complex 1 exhibited efficient catalytic activity toward selective epoxidation of cis-cyclooctene by using tert-butylhydroperoxide as an oxidant.