Synthesis, spectral, crystal structures, Hirshfeld surface analysis and DFT studies on bis(N,N-di(4-methoxybenzyl)dithiocarbamato-S,S′)zinc(II) and its imine adducts: new precursor for the preparation of hexagonal ZnS

Abstract

ABSTRACT[Zn(4-mbzdtc)2] (1), [Zn(4-mbzdtc)2(py)] (2), [Zn2(4-mbzdtc)4(4,4′-bipy)] (3), and [Zn(4-mbzdtc)2(2,2′-bipy)] (4), (where, 4-mbzdtc = N,N-di(4-methoxybenzyl)dithiocarbamate) were prepared and characterized by elemental analysis, infrared, 1H and 13C NMR spectroscopy and the structures of 1 and 3 were elucidated by X-ray crystallography. The monomeric structure of 1 shows a distorted tetrahedral geometry for zinc(II). The coordination geometry around zinc in dinuclear complex 3 is an intermediate between square pyramidal and trigonal bipyramidal. The downfield shift of NCS2 carbon signal for imine adducts of 2–4 compared to those found in parent complex 1 is attributed to the change in coordination number and steric effect exerted by the nitrogen donor ligand. Hirshfeld surface analysis was used to visualize intermolecular interactions in the crystal structure of 1 and 3. The geometry optimization of 1 is performed using DFT with the B3LYP-LANL2DZ basis set. Solvothermal decomposition of 1 yielded only hexagonal zinc sulfide nanoparticles. Zinc sulfide nanoparticles were characterized using powder X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectra and diffuse reflectance spectra. DRS study of ZnS nanoparticles shows the quantum confinement effect with a band gap of 3.74 eV.