Hydrazone-containing organotin(IV) complexes: synthesis, characterization, antimicrobial, antioxidant activity and molecular-docking studies

Abstract

The diorganotin(IV) complexes (5–20) were synthesized in the present research from 4-fluorophenoxyacetic hydrazide and salicylaldehyde derivatives-based hydrazone ligands (1–4) to get an effective biological agent to combat microbial and oxidant deformities. Numerous spectral techniques such as (¹H, ¹³C, ¹¹⁹Sn) NMR, UV–Vis, IR, and mass spectrometry were executed to illuminate the composition of complexes. These techniques ascertained tridentate chelation of hydrazone ligands with tin metal through enolic, phenolic oxygens and imine nitrogen, revealing pentacoordinated geometry of the complexes. The single crystal XRD of complex (5) confirmed distorted trigonal bipyramidal geometry. The TGA studies showed thermal stability up to 180 °C of the complexes, whereas the low conductance observed pointed to the non-electrolytic nature of the compounds. Furthermore, serial dilution assay was implemented to uncover the microbial inhibition efficacy (against six strains) of the compounds using ciprofloxacin and fluconazole. Among the synthesized compounds, (1, 8) exhibited comparable MIC value to standard. The compound (8) was reported as four times more potent than the fluconazole against C. albicans. Using DPPH assay, the antioxidant efficiency was examined which advocates enhanced efficacy of complexes than the ligands. The potency of complex (8) against C. albicans makes it a point of interest for molecular docking investigation, so, complex (8) and its ligand (1) were studied against protein of C. albicans (5TZ1), revealing the more efficacy of complex (binding energy-11.6 kcal/mol) than ligand. Further, the compounds were analysed for ADME prediction which concluded the efficacy of compounds as orally efficient pharmaceuticals.