Characterization and antimicrobial activity of organotin (IV) complexes of 2-(2',6'-diethylphenylamido) benzoates and 3-(2',6'-diethylphenylamido) propanoates

New organotin(IV) complexes with 2-[(2',6'-diethylphenylamido)]benzoic acid $(HL^1)$ and 3-[(2',6'- diethylphenylamido)]propanoic acid $(HL^2)$ were synthesized by the reaction of di- and triorganotin salts in the presence of triethylamine as base or dioctyltin oxide using a Dean and Stark trap for the removal of azeotropic water. All complexes were characterized by elemental analysis, IR, NMR, and mass spectral studies, and proof that tin-ligand coordination involves only the carboxylate group and complexes show hexa-coordinated geometry in solid state. Multinuclear NMR data show that triorganotin complexes exhibit 4-coordinated geometry while diorganotin complexes show a coordination number greater than 4, probably 5 or 6 in solution state. These complexes were screened to check their antimicrobial activity in vitro. The complexes of 2-[(2',6'-diethylphenylamido)]benzoic acid $(HL^1)$ were also checked for their insecticidal and anti-leishmanial activity. All the complexes show significant activity with few exceptions.