Oxovanadium-phosphazene complexes: Synthesis and characterization

Cyclic vanadium-phosphazene complexes in 5- and 6-coordination have been synthesized by the reaction of bis(acetylacetonato)oxovanadium(IV), [VO(acac)(2)], or trichlorooxovanadium(V), [VOCl3], with acyclic phosphazene ligands, [HN(PPh2NR)(2)], (where R = Ph or SiMe3) in 1:1 and 1:2 molar ratio. These green colored complexes correspond to the general formulae [VO(acac)L], [VOCl2L] and [VOClL2] (where L = [HN(PPh2NR)(2)]. They are fairly soluble in most organic solvents and sensitive to moisture. These complexes are characterized by various physico-chemical technique. viz elemental analyses (C, H, N, V and Cl), molecular weight determinations and spectral Studies including IR and NMR (H-1, C-13 and P-31), which indicated the monomeric nature of the complexes having a bidentate mode of bonding with the phosphazene ligand endowing a square-pyramidal or octahedral geometry around the vanadium atom, respectively.