Synthesis and crystal structures of bis(dibenzyl dithiocarbamato)Cu(II) and Ag(I) complexes: Precursors for Cu1.8S and Ag2S nano-photocatalysts

We report the synthesis and crystal structures of bis(dibenzyl dithiocarbamato) copper(II) and silver(I) complexes and their use as precursors to prepare Cu1.8S and Ag2S nanoparticles. Single crystal analysis of bis(dibenzyl dithiocarbamato)Cu(II) complex consist of a monomeric entity where the two dibenzyl dithiocarbamate ligands form a distorted square planar geometry around the Cu(II) ion. The bis(dibenzyl dithiocarbamato)Ag(I) formed hexameric coordination complex consisting of two distorted hexagonal Ag3S3 rings. The complexes were thermolysed at 220 °C to prepare copper sulphide and silver sulphide nanoparticles. Powder X-ray diffraction (p-XRD) patterns of the copper sulphide nanoparticles were indexed to digenite Cu1.8S, while silver sulphide nanoparticles were confirmed to be acathinite Ag2S. High-resolution transmission electron microscopy (HRTEM) images showed Ag2S nanoparticles with particle size in the range 11.4–27.4 nm while Cu1.8S nanoparticles are semi-spherical in shape with slightly agglomerated particles in the range 6.9–24.0 nm. The as-prepared nanoparticles were used as nano-photocatalysts for the degradation of methylene blue dye (MB) under UV light irradiation with degradation efficiency of 42.52% and 48.39% for Cu1.8S and Ag2S nanoparticles respectively.