Experimental and theoretical studies on cis-dioxomolybdenum(VI) complexes of ONN-donor thiosemicarbazone

Abstract

Cis-dioxomolybdenum(VI) chelate complexes with 5-chloro-2-hydroxybenzophenone S-methyl-4-phenylthiosemicarbazone (L) were synthesized in the general formula (MoO2 (L)D), where D is an odd- or even-numbered alcohol(methanol (1), ethanol (2), n-propanol (3), n-butanol (4), and allyl alcohol (5)). The structures of 1–5 were verified byelemental analysis, Fourier transform infrared (FT-IR), and 1 H NMR spectra. Complex 5 crystallizes in the monoclinicspace group P21/n, and its crystalline data showed a dimeric structure formed by a pair of intermolecular hydrogen bondswith 1.92 Å. These dimers are stacked in a similar crystalline structure as a single molecule. The experimental data werecompared with the theoretical results obtained by the quantum chemical calculations of the DFT/B3LYP method withLANL2DZ basis set. A detailed interpretation of the FT-IR spectra of the studied compounds was performed based onthe total energy distribution. In order to investigate the electronic structures and the UV-Vis spectrum of complex 5,time-dependent density functional theory calculation was taken into account. The interaction energies between the oddand even-numbered alcohols and remaining parts of complexes 1–4 were evaluated with the help of natural bondingorbital analysis. In addition, the basis set superposition error correction energies were calculated. The results wereevaluated by considering the coordinated alcohols with an even number of carbon atoms to have much higher interactionenergy than the next lower homologous alcohols with an odd number of carbon atoms.