Novel triorganotin(IV) carboxylates: Synthesis, structural features and antimicrobial, cytotoxicity, antioxidant, hemolysis, antileishmanial, anticancer studies

Abstract

Two carboxylic ligands, HL¹ {(Z)-4-(p-toluidino)-4-oxobut-2-enoic acid} and HL² {(Z)-4-(4-fluorophenylamino)-4-oxobut-2-enoic acid)} and their six novel triorganotin(IV) derivatives with the general formula R₃SnL (wherein R = Me (1, 4), Bu (2, 5) and Ph (3, 6) were synthesized, characterized and evaluated for in vitro biological applications. Single crystal XRD and FT-IR data of the triorganotin(IV) complexes (1, 2 and 4) showed that they were polymeric in nature and that the tin(IV) ion was in a distorted trigonal bipyramidal environment. However, multinuclear NMR data (¹H, ¹³C, ¹¹⁹Sn) suggested that the polymeric trigonal bipyramidal geometry remains intact for (Me)₃SnL and (Bu)₃SnL and (Ph)₃SnL compounds in solution-state, whereas it switches tetrahedral geometry for (Bu)₃SnL compound 5 which were analyzed for NMR in CDCl_3, a non-coordinating solvent. A detailed analysis of their structural, electronic and physico-chemical properties, using DFT at B3LYP/LANL2DZ level, revealed results consistent with the single crystal data. Additionally, the study of their frontier molecular orbitals, Mulliken charges and molecular electrostatic potential surfaces provided valuable insights into their structure-property-relationship and physicochemical properties. In vitro studies examining antimicrobial activity, cytotoxicity, antioxidant properties, hemolysis, antileishmanial effects, and anticancer potential have demonstrated higher efficacy of complexes compared to their corresponding ligands.