Synthesis, spectral, structural and DFT studies on Tl(III) dithiocarbamate complexes: Preparation of Tl2S nanoparticles from tris(N-benzyl-N-furfuryldithiocarbamato-S,S’)thallium(III)

Abstract

Tris(N,N-difurfuryldithiocarbamato-S,S’)thallium(III) (1), tris(N-benzyl-N-furfuryldithiocarbamato-S,S’)thallium(III) (2) and tris(N-furfuryl-N-(2-phenylethyl)dithiocarbamato-S,S’)thallium(III) (3) have been prepared and characterized by elemental analysis, IR and NMR (1H and 13C) spectroscopy. Single crystal X-ray structural analysis was carried out for 1. X-ray crystallography revealed that complex 1 is monomer. Thallium is hexacoordinated with six sulfur atoms from three chelating N,N-difurfuryl dithiocarbamate ligands in a distorted octahedral geometry. Complex 1 is further stabilized by various interactions such as CH…π (chelate), CH…π, CH…S and CH…O interactions. CH…O interactions lead to the formation of 18 membered macrocyclic ring. Hirshfeld surface analysis (dnorm surface and 2-D fingerprint plots) were performed using Crystal explorer 3.1 program. The major contributions for the crystal packing are from H…H, S…H/H…S, O…H/H…O and C…H/H…C interactions. Molecular optimization, molecular electrostatic potential and frontier molecular orbitals were calculated using DFT method for 1. DFT calculations on 1 revealed that HOMO was localized predominantly over furfuryl ring carbon atoms, whilst the LUMO was located on Tl and S atoms, with the HOMO-LUMO energy gap being 2.5067 eV. Thallium sulfide nanoparticles Tl2S-1 and Tl2S-2 have been prepared from complex 2 using conventional heating and microwave irradiation, respectively. The as-prepared Tl2S nanoparticles have been characterized by PXRD, EDS, HR-TEM, UV–vis absorption and fluorescence spectroscopy. The X-ray diffraction pattern confirms the rhombohedral phase of as-prepared Tl2S.