Synthesis, spectral characterization and X-ray crystal structure of biologically active organotin(IV) 3-[(3′,5′-dimethylphenylamido)]propanoates

A new ligand was prepared by reacting 3,5-dimethylaniline with succinic anhydride in glacial acetic acid at room temperature. A series of organotin(IV) carboxylates were prepared by reacting the ligand with R2SnCl2/R3SnCl (R = Me, Bu, Ph, Oct) in 1:2/1:1 molar ratio. The synthesized complexes were characterized by elemental analyses, FT-IR, multinuclear magnetic resonance (1H and 13C) and mass spectrometry. The structures of the ligand (HL) and complex (5) were determined by single crystal X-ray diffraction analysis. FT-IR data shows that the coordination takes place through both carboxylate oxygen atoms. NMR data confirm the tetrahedral geometry in solution. In the crystal structure of ligand (HL), centrosymmetrically related molecules are linked into dimers by N–H…O hydrogen bonding interactions, while in complex (5) coordination around the tin atom is trigonal bipyramidal, with the carbon atoms of the methyl groups occupying the equatorial plane and the O atoms of symmetry-related ligands at the apices. Organotin(IV) complexes were also screened for their antibacterial and antifungal activities, and the results suggested that the synthesized complexes are better antimicrobial agents as compared to the free ligand.