Di- and triorganotin(IV) complexes of 2-aminobenzoic acid with and without triphenylphosphine: synthesis, spectroscopy, semi-empirical study, and antimicrobial activities

Eight organotin carboxylates have been synthesized in quantitative yield by reaction of NaL (L = 2-aminobenzoate) with the di- and triorganotin chlorides and triphenylphosphine. All the complexes have been characterized by elemental analysis, IR, multinuclear NMR (H-1, C-13, and Sn-119), and mass spectrometry. The spectroscopic data indicate 1 : 2/1 : 1 M : L stoichiometry in 1, 3, 5, and 7 and 1 : 2 : 1/1 : 1 : 1 M : L : PPh3 stoichiometry in 2, 4, 6, and 8. FT-IR spectra clearly demonstrate metal attachment with both oxygens of the ligand and bidentate coordination in 1, 3, 5, and 7 while monodentate ligand for 2, 4, 6, and 8. In solid state, 1, 2, 5, and 6 exhibit six coordination whereas 3, 4, 7, and 8 show five coordination. The structural behavior is confirmed by semi-empirical study. NMR data reveal four-coordinate geometry in solution. These complexes were screened for antimicrobial activity in vitro. The screening tests show that tributyltin carboxylates are more potent antibacterial and fungicidal agents than corresponding methyl derivatives, and triphenylphosphine enhances the antibacterial and fungicidal activities of these complexes.