Synthesis and structural characterization of biologically active organometallic silicon and tin compounds derived from new triazole Schiff bases

This article describe the syntheses and characterization of some new diorganosilicon(IV) and diorganotin(IV) complexes having general formulae R₂MCl(L¹) (1a, 1b), R₂M(L¹)₂ (1c, 1d) R₂MCl(L²) (2a, 2b), and R₂M(L²)₂ (2c, 2d). The compounds were synthesized from the reaction of R₂MCl₂ with new Schiff bases (HL^1-2) in 1 : 1 and 1 : 2 molar ratios, where M=Si and Sn, R=CH₃. The Schiff bases HL¹ and HL² have been prepared by the reaction of 3-bromobenzaldehyde with 4-amino-5-mercapto-s-triazole and 4-amino-5-mercapto-3-methyl-s-triazole, respectively. The new Schiff bases and their metal complexes have been characterized by elemental analysis, molar conductance and spectroscopic studies including UV, IR, ¹H, ¹³C, ²⁹Si and ¹¹⁹Sn NMR spectroscopy. On the bases of these studies, the resulting complexes are proposed to have trigonal bipyramidal (compounds 1–4) and octahedral geometries (compounds 5–8). In vitro activities of ligands and their metal complexes against some Gram positive (Staphylococcus aureus and Bacillus subtilis), Gram negative (Escherichia coli and Pseudomonas aeruginosa) bacteria and fungi (Aspergillus Niger and A. Flavus) have been carried out. The antimicrobial data reveals that the organometallic compounds are superior to the free ligands and their toxicity has increased as per the increase in concentration.