Comparative Analysis of Structure and Biopotency of Di- and Triorganotin(IV) Carboxylates with Hexyl Backbone

Abstract— Chemists are pretty much acquainted with coordination compounds bearing carboxylate moieties. Nevertheless comprehensive literature on the subject correlating activity and toxicity with varied organotin(IV) carboxylates containing a diverse array of ligand moieties under identical experimental parameters is lacking. In view of the exciting structural and biological importance attributed to organotin(IV) compounds, the current research work involved synthesizing di- and triorganotin(IV) analogues of carboxylate ligand with hexyl aliphatic, aromatic and alicyclic backbone. The new organotin(IV) complexes with cyclohexane carboxylic acid (L₁), benzoic acid (L₂), and heptanoic acid (L₃) were synthesized by the reaction of di- and triorganotin(IV) salts in the presence of trimethylamine as base. The coordination mode of ligand, structural confirmation and geometry assignment of complexes were established using FT-IR, ¹H NMR and ¹³C NMR spectra. The IR data implied that in both di- and triorganotin(IV) carboxylates, the ligand moiety—(COO) acted as a bidentate group in solid state. ¹H and ¹³C NMR data revealed that tri and diorganotin(IV) complexes occurred as monomeric entities with tetrahedral geometry around tin in solution. The synthesized complexes were also evaluated for their antibacterial and antifungal activity. The results showed that synthesized complexes have greater inhibition potential against different strains of bacteria and fungi compared with the corresponding free ligands. Triorganotin(IV) compounds were found to be more potent against tested bacterial and fungal strains than that of diorganotin(IV) derivatives, having moderate antioxidant activity. Most of the organotin(IV) complexes of benzoic acid were found to be more potent against strains of bacteria and fungi than that of corresponding complexes of other ligands showing that for a biological activity to be shown by a complex, the role of ligand was crucial.