Synthesis and Characterization of Organotin(IV) Complexes Derived of 2-amino-5-nitrobenzoic Acid: In vitro Antibacterial Screening Activity

Problem statement: Tremendous studies have been carried out on organotin(IV) complexes derivatives of carboxylate anions. However, the synthesis and characterization as well as the in vitro antibacterial screening activity of organotin(IV) carboxylate derived of 2-amino-5-nitrobenzoic acid have not been carried out. Approach: Organotin(IV) carboxylate complexes derivative of 2-amino-5-nitrobenzoic acid, 2-NH₂-5-NO₂-C₆H₃COOH have been successfully synthesized. The acid and complexes obtained were characterized quantitatively using C, H, N and Sn elemental analysis as well as spectroscopic methods such as infrared (FTIR) and nuclear magnetic resonance (¹H, ¹³C, ¹H-¹³C HMQC and ¹¹⁹Sn NMR). Moreover, the complexes obtained were screened for their in vitro antibacterial screening activity. Results: Monomeric R₂Sn (2-NH₂-5-NO₂-C₆H₃COO)₂ (R = methyl 1, butyl 2) and dimeric {[(Bu₂Sn(2-NH₂-5-NO₂-C₆H₃COO)]₂O}₂ 3 as well as Ph3Sn(2-NH2-5-NO2-C6H3COO) 4 are obtained in solid state. Results of the infrared spectroscopy on the acid and complexes showed that the coordination took place via oxygen atoms from the carboxylate anions. Based on the 119Sn NMR solution study, the tin atom of both complexes 1 and 2 exhibit six-coordination respectively and complex 3 exhibits five- and six-coordination whereas the tin atom of complex 4 exhibits five-coordination. Conclusion: Pure complexes derived of 2-amino-5-nitrobenzoic acid have been successfully obtained. Triphenyltin(IV) are found to possess better in vitro antibacterial screening activity on two gram-positive bacterial compared to the parent acid.