Synthesis, spectroscopic, thermal and quantum chemical studies on trivalent erbium NO chelating sulfamonomethoxine-cyclophosph(V)azane complex

Novel hexachlorocyclophosph(V)azane of sulfamonomethoxine (L), was prepared and their coordinating behavior toward the lanthanide ion erbium (III) was studied. The structures of the isolated products were proposed based on elemental analyses, IR, UV-VIS, 1H NMR, 31P NMR, SEM, TEM, XRD, mass spectra, effective magnetic susceptibility measurements and thermogravimetric analysis (TGA). The coordination polyhedra of the eight donor atoms around the two erbium (III) ions are best described as distorted dodecahedral. Computational studies were carried out at the DFT-B3LYP/6-31G(d) level of theory on the structural and spectroscopic properties of L and its binuclear erbium (III) complex. Different tautomers of the ligand were optimized at the ab initio DFT level. Keto-form structure is about 30.5 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 in gas phase and DMF.