Synthesis, structural and DFT studies on thiosemicarbazone-based dioxomolybdenum(VI) complexes with co-ligands

5-Chloro-2-hydroxybenzophenone-S-methyl-4-phenylthiosemicarbazone (Eta L-2(1)) was synthesized from 4-phenylthiosemicarbazide. Reaction of Eta L-2(1) with [bis(acetylacetonato)dioxomolybdenum(VI)] gave the dioxomolybdenum(VI) complexes with [MoO2(L-1)(L-2)] composition where L-2 is n-pentanol, ethylene glycol monomethyl ether, ethyl acetate, isoamyl alcohol, pyridine, or gamma-picoline. The structures of the stable solid complexes were elucidated using elemental analysis, electronic, FTIR, and H-1 NMR spectra. Crystallographic analysis of [MoO2(L-1)(n-pentanol)] (1) clearly indicated the O,N,N-chelating thiosemicarbazone backbone and the distorted octahedral environment of the molybdenum atom. Complex 1 crystallizes in the monoclinic system with P2(1/n) space group and Z = 4. Moreover, the quantum chemical calculations supporting the experimental data of 1-6 are also reported in this study. Geometric optimization and theoretical vibrational spectra calculations of the complexes were performed by using the B3LYP density functional level of theory with LANL2DZ basis set employing density functional theory (DFT). Also, the non-covalent interaction (NCI) plot index analysis reveals the presence of different kinds of non-covalent interactions in [MoO2(L-1)(n-pentanol)] (1).