Safiah A. Alramadhan

Four Ni–phen complexes were prepared and characterized by FTIR and thermal analysis. The X-ray structure determination shows that the geometry around Ni^II ions in complexes 1, [Ni(phen)₂(H₂O)(ONO₂)](NO₃); 2, [Ni(phen)₂(H₂O)Cl]Cl; 3, [Ni(phen)(CH₃CN)(ONO₂)(O₂NO)] and 4, [Ni(phen)₃](NO₃)₂.H₂O.C₂H₅OH is considerably distorted octahedral. The coordination core geometries in 1, 2, 3 and 4 are NiN₄O₂, NiN₄OCl, NiN₃O₃ and NiN₆, respectively. The crystal packing and crystal supramolecularity analysis of the complexes reveal the importance of aryl∙∙∙aryl interactions, and both offset face-to-face (OFF) and edge-to-face (EF) motifs are dominant. Hydrogen bonding interactions in these structures reinforce aryl∙∙∙aryl interactions. FTIR proved the coordination of M-N and M-Cl as well as the presence of nitro groups in the complexes, while thermal analysis revealed that the loss of water, chloro and nitro groups occurred before the degradation of phenanthroline ligand in the complexes. DFT study indicates that a strong correlation exists among theoretical and experimentally determined geometric parameters with distorted octahedral geometry. The charge density in HOMO is localized on the metal halogen bond and nitrate group (NO₃⁻), whereas the LUMO cloud density is mainly distributed on the phen ring, which indicates the electroactive nature of the ring.

The green synthesis of zinc sulfide nanoparticles (ZnS NPs)-mediated plant extract is gaining importance because of its simplicity, cost-effectiveness, and ecofriendly nature. In this work, ZnS NPs were synthesized using garlic extract as NPs facilitating agent, characterized by Fourier transform infrared, X-ray diffraction, scanning electron microscope, and UVvisible, then their antibacterial and hemocompatibility were assayed. Analysis revealed a cubic phase, 2.33nm crystallite size, and a 3.75eV optical bandgap. Bioactivity test against Staphylococcus aureus and Escherichia coli indicated dose-dependent potency closer to that of azithromycin standard drug and more efficient on S. aureus (Gram-positive) than E. coli (Gram-negative) bacteria. Biocompatibility test in terms of erythrocyte hemolysis, in reference to normal saline and water as minimal and maximal controls, confirmed nontoxic substance up to 100μg/mL as the highest examined concentration and at which a lysis of 2.9 was detected. Therefore, it could be concluded that this biogenic method is effective in producing ZnS NPs with desirable properties for potential biomedical applications.

The aim of this work was to investigate the adsorptive performance of the polypyrrole-based KOH-activated carbon (PACK) in the removal of the basic dye crystal violet (CV) using a batch adsorption system. The equilibrium data, obtained at different initial CV concentrations ( ) and temperatures (25–45°C), were interpreted using the Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich isotherms, with the Langmuir model providing a better fit ( ) and a maximum adsorption capacity of 497.51 mg/g at 45°C. Under the examined conditions, the values of the thermodynamic parameters free energy, enthalpy, and entropy indicate a spontaneous, endothermic, and physisorption adsorption process. The kinetic data of the adsorption process were very well described by a pseudo-second-order model ( ). However, surface diffusion seems to be the main rate-controlling step. Thus, we concluded that PACK shows commercial potential for the removal of cationic dyes such as CV from industrial effluent.