Síntese, caracterização e avaliação da atividade antituberculose de complexos de prata e zinco com a base de Schiff N,N´-bis(tiofenil-2-metilideno)etano-1,2-diamina

Abstract

In the present work the Schiff base, N,N’-bis(thiophenyl-2-methylidene) ethane-1,2-diamine (BNH), was obtained from condensation reaction between ethylenediamine (en) and 2- thiophenecarboxaldehyde (TCA) using molar ratio1:2 (en:TCA). Two new silver(I) complexes with BNH were prepared by reacting BNH:AgNO3. When 1:1 molar ratio (M:L) was used, the polymeric complex [Ag(BNH)NO3]n is obtained where Ag(I) ions are coordinated by 2 N (imine group) from two different ligands and one oxygen from nitrate group. When 1:2 molar ratio (M:L) is used a monomeric and chelated complex – [Ag(BNH)2]NO3 was obtained. In this complex silver(I) ions are surrounded by 4 N (imine group) from two ligands. In the same way, the zinc(II) complexes were also tested, but the reactions between the BNH and ZnCl2 in 1:1 or 1:2 (M:L) result in the same complex formulated as [Zn(Cl)2(BNH)], where BNH is coordinated to Zn(II) ions by N (imine) and two chlorine ions complete the tetracoordination around zinc(II) ions. The compounds were characterized by elemental (C, H, N) and thermal analyzes (TG/DTA), IR, Raman, and Nuclear Magnetic Resonance spectroscopic techniques and X rays diffraction - monocrystal and powder. Besides the analytical, spectroscopic and structural data, the biological studies were performed. The antibacterial and cytotoxic properties of BNH and its three metal complexes were tested based on the activity Anti-MBT and IC50 using VERO cells. In addition, two ligands – N,N’-bis(thiophenyl-2-methyl)ethane-1,2-diamine (obtained by BNH reduction) and its hydrochloric derivative were synthesized and partially characterized. A gold(III) salt was also obtained and characterized by simple reaction between the diamine‘s hydrochloride and K[AuCl4] salt.