Synthesis, spectral and quantum chemical studies on NO-chelating sulfamonomethoxine–cyclophosph(V)azane and its Er(III) complex

•A novel cyclodiphosph(V)azane ligand, was synthesized and characterized by different tools.•Quantum chemical calculations were used to support the measured results.•Geometry optimization was performed at the level of B3LYP/6-31G(d).•Simulated IR and UV–VIS spectra showed agreement with the measured values.•Reactivity of the title compound was discussed in terms of accommodation of charge and HOMO picture.

Computational studies have been carried out at the DFT-B3LYP/6-31G(d) level of theory on the structural and spectroscopic properties of novel ethane-1,2-diol-dichlorocyclophosph(V)azane of sulfamonomethoxine (L), and its binuclear Er(III) complex. Different tautomers of the ligand were optimized at the ab initio DFT level. Keto-form structure is about 15.8 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. The structures of the novel isolated products are proposed based on elemental analyses, IR, UV–VIS, 1H NMR, 31P NMR, SEM, XRD spectra, effective magnetic susceptibility measurements and thermogravimetric analysis (TGA).

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