Synthesis, characterization and biological activity of diorganotin(IV) complexes of N-(3,5-dibromo-salicylidene)-α-amino acid

The diorganotin(IV) complexes of N-(3,5-dibromosalicylidene)-alpha-amino acid, R-2'Sn(2-O-3,5-Br2C6H2CH = NCHRCOO)(where R = H, Me, i-Pr, Bz; R' = n-Bu, Cy), were synthesized by the reactions of diorganotin dichlorides with in situ formed potassium salt of N-(3,5-dibromosalicylidene)-a-amino acid and characterized by elemental analysis, IR and NMR (H-1, C-13 and Sn-119) spectra. The crystal structures of n-Bu2Sn(2-O-3,5-Br(2)C(6)H2CH = NCHRCOO)(R = i-Pr, Bz) and Cy2Sn(2-O-3,5-Br2C6H2CH = NCHRCOO)(R = Me, Bz) were determined by X-ray single crystal diffraction and showed that the tin atoms are in a distorted trigonal bipyramidal geometry to form five- and six-membered chelate rings with the tridentate ligand. Bioassay results indicated that the compounds possess better in vitro antitumour activity against three human tumour cell lines, HeLa, CoLo205 and MCF-7, than cis-platin and moderate anti-bacterial activity against two bacteria, E. coli and S. aureus.