Ni(II) dithiocarbamate: Synthesis, crystal structures, DFT studies and applications as precursors for nickel sulfide and nickel oxide nanoparticles

Abstract

Four nickel(II) complexes based on dithiocarbamates, [Ni(dtc)2] (1,3) and [Ni(dtc)(NCS)(PPh3)] (2,4), (where dtc = N-(4-(dimethylamino)benzyl)-N-propyldithiocarbamate (1,3), N-butyl-N-(4-(dimethylamino)benzyl)dithiocarbamate (2,4)) have been synthesized. All the complexes were characterized by elemental analysis, IR, UV–Visible and NMR spectroscopy. The crystal structures of 2–4 were determined by single crystal X-ray diffraction. Homoleptic complex 3 and heteroleptic complexes 2 and 4 display distorted square planar coordination geometries, which are related to NiS4 (3) and NiS2NP (2 and 4) chromophores. Hirshfeld surface analysis of 2–4 revealed that the most important intermolecular interaction is the H⋯H contact. Theoretical structural geometries and electronic properties of 2–4 were calculated by means of density functional theory (DFT). The energy differences between the HOMO and LUMO are 1.7614, 2.0137 and 1.772 eV for 2–4, respectively. Sample 1 (a mixture of nickel sulfide and nickel oxide) and sample 2 (nickel oxide) nanoparticles were facilely synthesized by solvothermal and thermal decomposition of 3, respectively. The nanoparticles were characterized by PXRD, UV-DRS, TEM and EDS. The band gaps of samples 1 and 2 are 3.77 and 3.08 eV, respectively, calculated by the Tauc baseline, confirming their semiconductor nature and strong quantum confinement. The samples 1 and 2 were utilized for the photocatalytic degradation of methylene blue and rhodamine-6G in aqueous media under UV illumination.