Synthesis of nickel sulfide and nickel-iron sulfide nanoparticles from nickel dithiocarbamate complexes and their photocatalytic activities

[Ni(dtc)(2)] (dtc = N-(pyrrole-2-ylmethyl)-N-thiophenemethyldithiocarbamate (1), N-methylferrocenyl-N-(2-phenylethyl)dithiocarbamate (2), N-furfuryl-N-methylferrocenyldithiocarbamate (3), and (N-[pyrrole-2-ylmethyl]-N-thiophenemethyldithiocarbamato-S,S ')(thiocyanato-N)(triphenylphosphine)nickel(II) (4) complexes were prepared and characterized by elemental analysis, infrared, ultraviolet-visible, and nuclear magnetic resonance (H-1 and C-13) spectroscopies. The data were consistent with the formation of square planar nickel(II) complexes, which was confirmed by single-crystal X-ray diffraction studies on 2 and 4. Fe center dot center dot center dot Fe interactions exhibited by complex 2 led to supramolecular aggregation. The structure of 4 reveals intermolecular and intramolecular C-H center dot center dot center dot Ni anagostic interactions. The anion-sensing properties of 2 were studied with halide ions by cyclic voltammetry. It was observed that 2 acts as sensor for bromide. Complexes 1, 2, and 3, were utilized to prepare nickel sulfide, nickel-iron sulfide-1, and nickel-iron sulfide-2, respectively. The composition, structure, morphology, and optical properties of nickel sulfide and nickel-iron sulfides were examined using powder X-ray diffraction, transmission electron microscopy, energy-dispersive X-ray spectroscopy, ultraviolet-visible, fluorescence, and infrared spectroscopy. Powder X-ray diffraction patterns of nickel sulfide, nickel-iron sulfide-1, and nickel-iron sulfide-2 indicate the formation of orthorhombic Ni9S8, cubic NiFeS2, and cubic Ni2FeS4, respectively. The photocatalytic activities of as-prepared nickel sulfide and nickel-iron sulfide-1 nanoparticles were investigated for photodegradation of methylene blue and rhodamine-B under ultraviolet irradiation. Nickel-iron sulfide-1 nanoparticles show slightly higher photodegradation efficiency compared with the nickel sulfide nanoparticles.