Abstract
Novel dioxocyclodiphosph(V)azane of o-aminopyridine (H2L), was prepared and their coordinating behavior towards the transition metal ion Cu(II) was studied. The structures of the isolated products are proposed based on elemental analyses, IR, UV-Vis., H-1 NMR, P-31 NMR, mass spectra, effective magnetic susceptibility measurements and thermogravimetric analysis (TGA). The coordination polyhedra of the eight donor atoms about both Cu(II) atoms are best described as distorted dodecahedral. Computational studies have been carried out at the DFT-B3LYP/6-31G(d) level of theory on the structural and spectroscopic properties of L and its binuclear Cu(II) complex. Different tautomers of the ligand were optimized at the ab initio DFT level. Keto-form structure is about 30.450 kcal/mol more stable than the enol form (taking zpe correction into account). Simulated IR frequencies were scaled and compared with that experimentally measured. TD-DFT method was used to compute the UV-VIS spectra which show good agreement with measured electronic spectra.