Spectral and biological studies of newly synthesized organotin(IV) complexes of 4-({[(E)-(2-hydroxyphenyl)methylidene]amino}methyl)cyclohexane carboxylic acid Schiff base

Abstract

The new organotin(IV) complexes with 4-({[(E)-(2-hydroxyphenyl)methylidene]amino}methyl)cyclohexane carboxylic acid (HL, Schiff base) were synthesized by the reaction of di- and triorganotin salts in the presence of triethylamine as base or dioctyltin oxide using Dean and Stark trap for the removal of azeotropic water. All complexes were characterized by elemental analysis, IR, NMR (¹H and ¹³C) and mass spectrometry. The IR data indicate that in both di- and triorganotin(IV) carboxylates, the ligand moiety -COO acts as a bidentate group in solid state. Multinuclear NMR data show that triorganotin complexes exhibit the four-coordinated geometry, while diorganotin(IV) complexes show the coordination number greater than four, probably five or six, in solution state. These compounds were screened for antibacterial activities against six pathogenic bacterial strains. The activities were measured in terms of inhibition zones (mm). Antifungal activity was determined against six pathogenic fungal strains, cytotoxicity by the brine shrimp lethality assay. Results for antibacterial and antifungal activity, and cytotoxicity of these compounds demonstrate that complexes exhibit significant biological activity with few exceptions.