In this study, two copper(II) complexes, [Cu(C₆H₈N₃S₂)₂]Cl₂ (1) and [Cu(C₇H₁₀N₃S₂)₂]Cl₂·H₂O (2), were synthesized from 2-(thiophen-2-ylmethylene)hydrazine-1-carbothioamide (L₁H) and 2-(1-(thiophen-2-yl)ethylidene)hydrazine-1-carbothioamide (L₂H) respectively and characterized using various spectroscopic techniques and elemental analyses. The as-prepared complexes were used as single-source precursors for the synthesis of oleylamine-capped (OLA@Cu_xS_y), hexadecylamine-capped (HDA@Cu_xS_y), and dodecylamine-capped (DDA@Cu_xS_y) copper sulphide nanoparticles (NPs) via the thermolysis method at 190 °C and 230 °C and then characterized using powder X-ray diffraction (p-XRD), UV-visible spectroscopy, transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The p-XRD diffraction patterns confirmed the formation of crystalline rhombohedral digenite Cu₉S₅ with the space group R-3m. The TEM images showed the formation of nanoparticles of various shapes including hexagonal, rectangular, cubic, truncated-triangular, and irregularly shaped Cu₉S₅ nanomaterials. The SEM results showed aggregates and clusters as well as the presence of pores on the surfaces of nanoparticles synthesized at 190 °C. The UV-visible spectroscopy revealed a general blue shift observed in the absorption band edge of the copper sulphide NPs, as compared to bulk Cu_xS_y, with energy band gaps ranging from 2.52 to 3.00 eV. Energy-dispersive X-ray spectroscopy (EDX) confirmed the elemental composition of the Cu₉S₅ nanoparticles. The nanoparticles obtained at 190 °C and 230 °C were used as catalysts for the photocatalytic degradation of methylene blue (MB) under UV irradiation. Degradation rates varying from 47.1% to 80.0% were obtained after 90 min of exposure time using only 10 mg of the catalyst, indicating that Cu₉S₅ nanoparticles have potential in the degradation of organic pollutants (dyes).

Ni(II), Cu(II), and Zn(II) complexes of the tridentate heterocyclic ligand, 2-(phenyl(pyridin-2-yl)methylene)hydrazine-1-carbothioamide (HL) have been synthesized and characterized by various spectroscopic techniques and elemental analyses. Infrared spectroscopy shows that the ligand coordinates to the metal ions through the azomethine and pyridine nitrogen atoms as well as the sulfur atom of the thioamide group to form a tridentate chelate system. In vitro screening of metal complexes against four bacterial strains (Staphylococcus aureus (ATCC 43300), Klebsiella pneumoniae (ATCC 700603), Methicillin resistant staphylococcus aureus (ATCC 33591), Shigella flexneri (NR 518)) and four fungal strains (Candida albicans (NR 29444), Candida albicans (NR 29445), Candida albicans (NR 29451), Candida krusei (HM 1122)) indicate that the Cu(II) complex showed good antibacterial activity on Methicillin resistant staphylococcus aureus (ATCC 33591) while the Zn(II) complex showed moderate activity against some of the bacterial and fungi strains. Antioxidant studies reveal that the complexes are more potent than the ligand to eliminate free radicals, with the Ni(II) complex showing the best free radical scavenger.

We report the synthesis of lead(II) complexes of 2-(thiophen-2-ylmethylene) hydrazine-1-carbothioamide (1) and 2-(1-(thiophen-2-yl) ethylene) hydrazine-1-carbothioamide (2), which were used as single source precursors in hexadecylamine (HDA) and oleylamine (OLA) at 190, 230, and 270°C to synthesize lead(II) sulfide nanoparticles. Optical studies by UV–vis analysis showed a general blue shift in the absorption band edge of the PbS nanoparticles (NPs) with energy bandgaps determined by Tauc’s plots ranging from 2.15 to 3.11 eV. The development of NPs with a variety of morphologies that changed with temperature and precursor type was demonstrated by morphological characterization using scanning electron microscopy and transmission electron microscopy. Cubic, rod-shaped, and nearly spherical-shaped PbS were formed. Powder X-ray diffraction (p-XRD) structural studies revealed the face-centered cubic structure of PbS nanoparticles. The elements contained in the nanoparticles were identified by energy dispersive X-ray spectroscopy (EDX). These results suggest that the size, shape, and optical properties of the synthesized PbS NPs were affected by reaction temperature, capping group, and precursor type. Under UV irradiation, the photocatalytic activity of HDA-capped PbS nanoparticles on the degradation of methylene blue dye ranged from 28.3% to 60.0%, with lead sulfide nanoparticle obtained by thermolysis of complex (1) at 230°C showing the highest photocatalytic efficiency (60.0%).

Iron oxide nanoparticles were synthesized by the chemical precipitation method at 25 and 80 °C using polyvinylpyrrolidone (PVP) and aloe vera/polyvinyl pyrrolidone (AP) as capping agents. FTIR bands at 1584-1455 and 522-561 cm-1 confirm the formation of PVP- and AP-capped iron oxide nanoparticles. The formation of magnetite and hematite phases was confirmed by powder X-ray Diffraction patterns. The elemental composition of the synthesized particles was confirmed by EDX. SEM analysis revealed a mixed morphology of spherical and irregular-shaped particles of average crystallite sizes ranging from 9 to 58 nm, as estimated from XRD and SEM measurements. Both PVP- and AP-capped nanoparticles were used as catalysts for the photocatalytic degradation of methylene blue under ultraviolet (UV) irradiation. After 180 min of irradiation with 20 mg of photocatalyst, degradation efficiencies of 53-82% were obtained, with AP-capped nanoparticles being more efficient, suggesting their potential as effective materials for the photocatalytic degradation of toxic dyes in wastewater.