New tri- and di-alkylstannyl 2-(1H-indol-3-yl)ethanoates: synthesis, characterization and biological screenings

A series of triorganotin(IV) compounds {Me3SnL (1), Bu3SnL (2), Ph3SnL (3)} and di-organotin(IV) complexes {Me2SnL2 (4), Bu2SnL2 (5) and Ph2SnL2 (6)}, where Me = methyl, Bu = butyl, Ph = phenyl and L = 2-(1H-indole-3-yl)acetate) have been synthesized and characterized by FT-IR and multinuclear NMR (H-1-, C-13- and Sn-119-NMR) spectroscopy. Tri- and diorganotin(IV) derivatives exhibited five- and six-coordinate geometries, respectively, in solid state as evident from the Delta nu value. Five-coordinate trigonal bipyramidal and six-coordinate octahedral geometry was assigned to 1 and 4 in solution state based on NMR data as evident from (2)J(Sn-119,H-1) and (1)J(Sn-119-C-13) coupling constant values, which was further attested by Sn-119 NMR. Single crystal XRD analysis on 1 revealed that it exhibited polymeric crystal structure with distorted trigonal bipyramidal geometry around the tin center with two unequal Sn-O bonds. The screening of the synthesized compounds for cytotoxicity showed good activity in comparison to cis-platin. They have also displayed moderate to good antimicrobial activities.