Synthesis, spectral and structural studies on NiS2PN and NiS2P2 chromophores and use of Ni(II) dithiocarbamate to synthesize nickel sulfide and nickel oxide for photodegradation of dyes

Abstract

The substitution of one of the dithiocarbamate ligands in homoleptic [Ni(dtc)2] (1) complex (dtc = N,N-di(4-methoxybenzyl)dithiocarbamate) with the phosphine ligands gave heteroleptic [Ni(dtc)(PPh3)(NCS)] (2), [Ni(dtc)(PPh3)2] ClO4 (3) and [(dtc)(dppe)] ClO4 (4) complexes. The complexes 2–4 were characterized by elemental analysis, spectroscopy and single crystal X-ray diffraction analysis. Single crystal X-ray diffraction studies revealed that 2–4 adopt distorted square planar geometry. Non-covalent interactions in 2–4 were quantified using Hirshfeld surface analysis. The study of single crystal X-ray diffraction of 2–4 shows that various interactions such as C–H⋯π (chelate), C–H⋯π, C–H⋯O and C–H⋯S among molecules of complexes 2–4, participate in cooperative way to stabilize the supramolecular interactions. DFT calculations were used to determine the electronic structure and properties of 2. The HOMO-LUMO energy difference (2.7445 eV) is observed to be small which shows the low kinetic stability of 2. Nanoparticles of nickel sulfide and nickel oxide were successfully synthesized by solvothermal and thermal decomposition of 1, respectively and characterized by powder X-ray diffraction (PXRD), High Resolution Scanning Electron Microscopy (HRSEM), Energy Dispersive Spectroscopy (EDS) and UV Diffuse Reflectance Spectroscopy (UV-DRS). The photocatalytic activity of both nanoparticles was investigated for degradation of methylene blue and rhodamine 6G under UV irradiation. The results revealed that the nickel oxide has higher photocatalytic activity than nickel sulfide.