Newly designed organotin(IV) carboxylates with peptide linkage: Synthesis, structural elucidation, physicochemical characterizations and pharmacological investigations.

Fourteen new organotin(IV) carboxylate complexes with peptide linkage of (2-(4-methoxy-2-nitrophenylcarbamoyl)benzoic acid) were successfully synthesized and characterized by elemental analyses, FT-IR, NMR (1H, 13C and 119Sn) and single crystal X-ray techniques. FT-IR results of the sodium salt of 2-(4-methoxy-2-nitrophenylcarbamoyl)benzoic acid and complexes showed that the coordination took place via oxygen atoms of the carboxylate group. 1J(119Sn-13C), 2J(119Sn-1H) and θ values calculated from 1H and 13C NMR data using Lockhart's equation reveal a trigonal bipyramidal geometry for triorganotin(IV) derivatives and an octahedral geometry for diorganotin(IV) derivatives. Crystallographic data for three triorganotin(IV) complexes (1-3) showed the tin has distorted trigonal bipyramidal geometry. In vitro anticancer activity against lung carcinoma (H-157) and kidney fibroblast (BHK-21) cell lines as well as antileishmanial activity against the promastigote forms of leishmania major of the synthesized compounds were also studied and the complexes were found biologically active. The in vitro antibacterial activity of most of the synthesized organotin(IV) derivatives against the studied bacterial pathogens is higher than those of the standard 3rd generation antibiotics such as Tetracycline, Penicillin G, Ampicillin, Amoxicillin. This suggest the use of these newly designed organotin(IV) derivatives as potent antibiotics. The synthesized compounds interact with DNA via intercalative mode of interaction. Viscosity measurement results also support the intercalative mode of interaction for the compounds with DNA.