Thione tautomer of hydrazone-carbodithioate chelator-derived Cu(II) and Zn(II) complexes as potential antibacterial agents: DFT computations and UV-assisted photocatalytic degradation of Rose Bengal dye

• Published in: Journal of molecular liquids 2023-09, Vol.385, p.122325, Article 122325
• Main Authors: Elzaref, Ahmed S., Elgammal, Walid E., Mosaad Abdallah, Abanoub, Al-Mhyawi, Saedah R., Abdellatif, Haitham A., Abdou, Amr M., Eliwa, Essam M., Ibrahim, Islam, Elfeky, Ahmed S.
• Format: Article
• Language: English
• Subjects: Antibacterial activity; DFT computations; Hydrazone-carbodithioate ligand; Photocatalytic degradation; Rose Bengal dye; Water treatment
• ISSN: 0167-7322; 1873-3166
• DOI: 10.1016/j.molliq.2023.122325

•Preparation of new hydrazone-carbodithioate ligand 3 and its Cu(II) with Zn(II) complexes.•Confirmation of complexation by DFT computations.•Photocatalytic removal of Rose Bengal dye under UV illumination. A new hydrazone-carbodithioate ligand 3 and its Cu(II) and Zn(II) complexes were chemically synthesized. The structural profile was well-defined through various analytical techniques encompassing FT-IR, EI-MS, NMR, elemental analysis, EDX, and XRD. Their morphological microstructure was examined by SEM analysis. Also, their thermal stability and optical energy bandgap were studied through TGA and UV–Vis-NIR spectroscopy, respectively. XRD patterns proved the crystallinity nature of the ligand and the amorphous behavior of its complexes. The Cu(II) chelate manifested an effective photocatalytic decolorization against RB dye under UV light with degradation efficiency (DE) approaching 96.9 % after 150 min. Whilst, the Zn(II) counterpart exhibited DE of about 86.8 % under the same conditions. TGA proved the absence of either water or solvent molecules in the complexes and authenticated the highest thermal stability of the Cu(II) complex. Furthermore, its kinetic constant (0.00972 min−1) compared to the zinc one (0.00689 min−1), confirmed its outstanding performance in the degradation process. Optical measurement as well supported this trend by the lowest energy bandgap of copper chelate (2.2 eV). Consequently, this Cu(II) complex could serve as an effective photocatalyst to remove RB dye and other pollutants. Theoretically, DFT computations approved the complexation reaction and emphasized the octahedral geometry of our coordinated compounds. The results of the antibacterial activity of the ligand and both Cu(II) and Zn(II) complexes were insignificant against P. aeruginosa (ATCC 27853) and K. pneumoniae (ATCC27736), as representatives of Gram-negative bacteria. However, Cu(II) complex was the most effective with MIC of 64 µg/mL and MBC of 64 µg/mL compared with MIC and MBC of 128 µg/mL and 256 µg/mL, respectively for Zn(II) complex against S. aureus (ATCC 33592) as representative of Gram-positive bacteria. Meanwhile, the ligand scored MIC and MBC of 256 µg/mL and > 256 µg/mL, respectively, and ofloxacin scored MIC and MBC of 0.5 µg/mL and 1 µg/mL, respectively against S. aureus (ATCC 33592).