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    Öğe
    From coordination-induced tautomerism to therapeutics: Structural, supramolecular, and antimicrobial insights into a Hg (II)-thiosemicarbazone complex
    (Elsevier, 2026) Choudhury, Rizwana Begum; Shahnowaz, Toufique; Mukherjee, Souryadeep; Baildya, Nabajyoti; Sahin, Onur; Choudhury, Nurul Alam; Roy, Subhadip
    A new Hg(II) complex 1 was synthesised from a 3-methoxysalicylaldehyde-4-methylthiosemicarbazone ligand (H2L) via one-pot reaction and characterized by FT-IR, 1H NMR, mass spectroscopy, elemental analysis, and single-crystal X-ray diffraction analysis. The complex 1 adopts a distorted seesaw [HgN2S2] coordination geometry. Coordination to Hg(II) promotes a thione-thiol tautomeric conversion in the ligand (H2L), forming a deprotonated thiolate donor. Structural analysis, combined with Hirshfeld surface and enrichment ratio evaluations, unveiled that O & ctdot;H and C & ctdot;C contacts play dominant roles in supramolecular stabilization. Density Functional Theory (DFT) analysis suggests a substantial amount of charge transfer from H2L to Hg(II). These results highlight how the interplay between coordination-induced tautomerism and noncovalent forces governs the molecular organization of the Hg(II) complex. Furthermore, the antibacterial efficacies of Hg(II) complex 1 and the free ligand (H2L) towards Gram-positive bacterial strains (viz. Staphylococcus cohnii, Mammaliicoccus lentus, Bacillus cereus, and Corynebacterium stationis) and Gram-negative bacterial strains (viz. Klebsiella pneumoniae, Enterobacter cloacae, Salmonella enterica, and Shigella sonnei) have been evaluated. Moreover, to explore the mechanism of the antibacterial action of 1, time-kill kinetic assay, deoxyribonucleic acid (DNA) cleavage potential, and molecular docking studies are performed.
  • [ X ]
    Öğe
    Insights into Supramolecular Networks Engineered via Tetrel and Hydrogen Bonding Interactions in Hemidirected Lead(II) Complexes
    (Amer Chemical Soc, 2025) Bhattacharjee, Tirtha; Nath, Sourav; Roy, Subhadip; Gomila, Rosa M.; Sahin, Onur; Kaminsky, Werner; Frontera, Antonio
    In this study, we explore the role of tetrel bonds (TtBs) and hydrogen bonds (H-bonds) in directing supramolecular crystal packing via self-assembly in two lead(II) chelates: [Pb(tren)(i-mnt)] (1) and [Pb4(tetraen)2(i-mnt)4] (2) [i-mnt -2 = 1,1-dicyanoethylene-2,2-dithiolate, tren = diethylene triamine, and tetraen = tris(2-aminoethyl)amine]. Both complexes were synthesized and isolated, and their solid-state structures were determined through single-crystal X-ray diffraction analysis. The secondary ligands (tren, tetraen) influence the coordination pattern of i-mnt -2 toward the Pb2+ center, generating diverse asymmetric geometries. Complex 1 is a vacant octahedral chelate, while complex 2 is a cocrystalline aggregate of crystallographically independent two cationic [Pb(tetraen)]+2 and two anionic [Pb(i-mnt)2]-2 inversion twins, each displaying seesaw geometry. These hemidirected lead(II) complexes with aliphatic ligands are the first of their class that display PbS, PbN TtB type secondary interactions in self-assembly processes, building homo- and heterodimers. Apart from TtBs, N-HN, N-HS, C-HN, and C-HS type H-bonds also engineer the supramolecular networks, generating diverse chain and ring geometry with requisite stability. DFT calculations and quantum theory of atoms-in-molecules analyses explored the nature of TtBs between hemidirected Pb(II) and the thiolate/cyano end of i-mnt -2 in formed dimers and their pivotal role in stabilizing and elucidating the electronic architecture of dimers. In addition, Hirshfeld surface analysis corroborates with X-ray and DFT results, exploring the existence of TtBs, H-bonds, and other noncovalent interactions that assist in the construction of stable supramolecular networks.