Abstract
Seven new Schiff base complexes of oxovanadium(IV), [VO(L)(H2O)], where H2L = H2bmpph-gls, H2bumpph-gls, H2iso-vmpph-gls, H2pmpph-gls, H2iso-bumpph-gls, H2ampph-gls, and H2vmpph-gls, have been synthesized by the reaction of VOSO4·5H2O and the said ligands in aqueous ethanol. The resulting complexes have been characterized on the basis of elemental analysis, vanadium determination, molar conductance, magnetic measurements, thermogravimetric (TG) analysis, infrared, electronic mass, and electron spin resonance studies. The thermal decomposition processes of one representative complex is discussed, and the order of reaction (n) and the activation energies (Ea) have been calculated from TG and differential TG curves. Molecular geometry optimizations, molecular surface electrostatic potentials, vibrational frequency calculations, bond lengths, bond angles and dihedral angles, and natural atomic charges obtained by natural bond orbital and Mulliken population analysis and calculations of molecular energies, highest occupied molecular orbital and lowest unoccupied molecular orbital were performed with the Gaussian 09 software package using density functional theory methods with Becke3–Lee–Yang–Parr (B3LYP) hybrid exchange–correlation functional and the standard 6-311G(+) basis set for (ampph-glsH2) and LANL2DZ basis set for one of its complexes, [VO(ampph-gls)(H2O)]. No imaginary frequency was found in the optimized model compounds, and hence it ensures that the molecule is in the lowest point of the potential energy surface, that is, an energy minimum. Finally calculated results were applied to simulate infrared spectra which show good agreement with observed spectra. Based on experimental and theoretical data, suitable square pyramidal structures have been proposed for these complexes.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have