Synthesis, spectroscopic characterization, density functional theory analysis, and molecular docking studies of diorganotin (IV) complexes with sterically congestedligands

Diorganotin (IV) complexes have attracted considerable attention due to their diverse structural features and promising biological properties. The investigation into diorganotin (IV) compounds as potential antimicrobial agents is an active and captivating area of research, particularly emphasizing the synthesis and characterization of diorganotin (IV) complexes with bioactive and sterically hindered ligands. In this study, novel diorganotin (IV) azomethine chelates were synthesized from sterically hindered 4-(2’-mercapto-phenyl-iminoaryl/alkyl)-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-ones, characterized, and evaluated for their antimicrobial potential. These complexes were obtained by reacting dimethyltin dichloride with the corresponding disodium salts in benzene and characterized through infrared, 1H, 13C, and 119Sn nuclear magnetic resonance spectroscopy, along with molecular weight determination. Structural optimization and electronic property analyses were performed using density functional theory (DFT) at the B3LYP/LanL2DZ level. Conceptual DFT descriptors indicated subtle variations in reactivity, with Chelate-4 exhibiting the highest softness and the lowest energy gap, suggesting enhanced electron-accepting capability. Molecular docking studies were conducted on the ligand moieties (L-1 to L-4) against proteins from Gram-positive and Gram-negative bacteria using cephalosporin and sulfamethoxazole as reference drugs. Ligand L-4 displayed superior binding affinities across all targets, aligning with its DFT-predicted reactivity. Absorption, distribution, metabolism, and excretion analysis revealed that while L-1 and L-2 showed favorable drug-likeness and oral bioavailability, L-4 demonstrated higher lipophilicity and possible metabolic concerns despite its potent antibacterial potential.
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