Co(III), Ni(II), Zn(II) and Cd(II) complexes with (2-acetyl-2-thiazoline) thiosemicarbazone: synthesis, characterization, x-ray structures and antibacterial activity

Abstract

The new ligand 2-acetyl-2-thiazoline thiosemicarbazone (HATtsc) and the complexes [Co(ATtsc)2]2[CoCl4]·2H2O (1), [Co(ATtsc)2]NO3·H2O (2), [Ni(HATtsc)2](NO3)2 (3), [ZnCl2(HATtsc)]·CH3CN (4), [{CdCl(HATtsc)}2(μ-Cl)2]·2H2O (5) and [{Cd(NO3)(HATtsc)}2(μ-NO3)2] (6) were isolated and characterized by a variety of physico-chemical techniques and X-ray diffraction. The structure of HATtsc in 1 and 2 presented a thiolate form while in 3–6 the thione form was present, as it was in free ligand. In addition, we studied the antibacterial activity of the ligand and complexes 2–6 against some representative bacteria. Cd(II) complexes were more active against Staphylococcus epidermidis, Staphylococcus aureus, Enterococcus faecalis, Escherichia coli and Bacillus subtilis than organic ligand. Conversely, Cd(II) compounds seemed to interfere in the cell separation of B. subtilis.

El nuevo ligando 2-acetil-2-tiazolina tiosemicarbazona (HATtsc) y los complejos [Co(ATtsc)2]2[CoCl4]-2H2O (1), [Co(ATtsc)2]NO3-H2O (2), [Ni(HATtsc)2](NO3)2 (3), [ZnCl2(HATtsc)]-CH3CN (4), [{CdCl(HATtsc)}2(μ-Cl)2]-2H2O (5) y [{Cd(NO3)(HATtsc)}2(μ-NO3)2] (6) se aislaron y caracterizaron mediante diversas técnicas físico-químicas y difracción de rayos X. La estructura de HATtsc en 1 y 2 presentaba una forma tiolato, mientras que en 3-6 estaba presente la forma tiona, al igual que en el ligando libre. Además, estudiamos la actividad antibacteriana del ligando y los complejos 2-6 frente a algunas bacterias representativas. Los complejos de Cd(II) fueron más activos frente a Staphylococcus epidermidis, Staphylococcus aureus, Enterococcus faecalis, Escherichia coli y Bacillus subtilis que el ligando orgánico. Por el contrario, los compuestos de Cd(II) parecían interferir en la separación celular de B. subtilis.