Synthesis and characterization of oxime-modified phenylimido vanadium(V) isopropoxide and their hydrolytic study

Abstract

Heteroleptic complexes of the type [V(NPh)(O i Pr)3-n {(ONC)(CH3)(C4H3O-2)} n ] {where n = 1 (1), 2 (2) and 3 (3)} were synthesized by the reactions of [V(NPh)(O i Pr)3] (A) with 2-acetylfuryl oxime in different molar ratios in anhydrous benzene. All these new derivatives have been characterized by elemental analyses, Fourier transform infrared spectroscopy, nuclear magnetic resonance (1H, 13C {1H}), 51V) and fast atom bombardment mass spectral studies. Spectral studies appear to be indicating mono-dentate and bi-dentate mode of attachment of the oximato moieties in the solution and solid state, respectively. Fast atom bombardment mass study of one of the representative derivative, [V(NPh){(ONC)(CH3)(C4H3O-2)}3] (3) suggests the monomeric nature of all these complexes. Thermogravimetric curve of [V(NPh){(ONC)(CH3)(C4H3O-2)}3] (3) shows large thermal events. Hydrolysis of [V(NPh)(O i Pr)3] (A) and [V(NPh){(ONC)(CH3)(C4H3O-2)}3] (3) in moist propan-2-ol medium yielded vanadia, (a) and (b), respectively. However, hydrolysis of [V(NPh)(O i Pr)3] (A) in n-hexane medium using calculated amount of water yielded hybrid material, (vn).The presence of (V = NPh) group in (vn) is confirmed by Fourier transform infrared spectroscopy and nuclear magnetic resonance spectral studies as well as by the thermogravimetric study. The X-ray diffraction patterns of vanadia, (a) and (b) indicate formation of orthorhombic phase and the scanning electron microscope images of (a) and (b) show rod like morphology of the crystallites. Absorption spectra of vanadia, (a) and (b) indicate energy band gaps of 2.62 and 2.43 eV, respectively. Heteroleptic complexes of the type [V(NPh)(O i Pr)3-n {(ONC)(CH3)(C4H3O-2)} n ] {where n = 1, 2 and 3} were synthesized by the reactions of [V(NPh)(O i Pr)3] with 2-acetylfuryl oxime. Hydrolysis of [V(NPh)(O i Pr)3] and [V(NPh){(ONC)(CH3)(C4H3O-2)}3] in moist propan-2-ol medium yielded vanadia in orthorhombic phase, whereas, hydrolysis of [V(NPh)(O i Pr)3] in n-hexane medium yielded hybrid material containing (V = NPh) linkages.