Synthesis, characterization, and biological evaluation of eight new organotin(IV) complexes derived from (1R, 2S) ephedrinedithiocarbamate ligand

Abstract

The synthesis of eight new organotin derivatives containing ephedrine-substituted dithiocarbamate ligands [R3Sn(ephedtc)] 2–5. 2: R = Me; 3: R = Bu; 4: R = Cy; 5: R = Ph and [R2Sn(ephdtc)2] 6–9. 6: R = Me; 7: R = Bu; 8: R = t-Bu; 9: R = Ph is reported. The complexes were obtained from sodium ephedrinedithiocarbamate [Na(ephedtc)] 1 and the corresponding tri-organotin(IV) chlorides, R3SnCl 2–5 or di-organotin(IV) dichlorides, R2SnCl26–9. They were characterized by elemental analysis, IR, and NMR spectroscopy (1H, 13C, and 119Sn). The infrared spectra (solid-state) suggest that the Sn(IV) is coordinated to the ligand ephedtc, through the two sulfur atoms in an anisobidentate coordination mode. In solution, the 119Sn NMR indicates the coordination numbers: tetracoordinated for 2–4, pentacoordinate for 5, and hexacoordinated for 6–9. The single-crystal X-ray diffraction analysis of 4 reveals an anisobidentate coordination mode with a trigonal bipyramid distorted geometry around the Sn(IV). All compounds except 2, show inhibition in at least one bacterial strain, and 7 and 9 have the best antibacterial activity, mainly in the clinically isolated strains.