Biological screening, DNA interaction studies, and catalytic activity of organotin(IV) 2-(4-ethylbenzylidene) butanoic acid derivatives: synthesis, spectroscopic characterization, and X-ray structure

Abstract

A series of organotin(IV) carboxylates, [Me2SnL2] (1), [Bu2SnL2] (2), [Oct2SnL2] (3), [Me3SnL] (4), and [Ph3SnL] (5), where L = 2-(4-ethylbenzylidene) butanoic acid, have been synthesized and characterized by elemental analysis, FT-IR, and NMR (1H, 13C, and 119Sn). [Me3SnL] (4) was analyzed by single crystal X-ray analysis which showed polymeric structure with distorted trigonal bipyramidal geometry. The complexes were screened for biological activities including antibacterial, antifungal, and cytotoxic activities. UV–vis absorption studies of HL, 1 and 4 with SS-DNA revealed groove binding as well as intercalation, which may be due to the presence of planar phenyl groups that facilitate interaction with DNA. The determined intrinsic binding constants, 6.04 × 103 M−1 (HL), 9.6 × 103 M−1 (1), and 1.7 × 104 M−1 (4), showed that HL and 1 have less binding strength than 4. The catalytic activities of di- and tri-organotin(IV) complexes were assessed in transesterification of triglycerides (linseed oil) into fatty acid methyl esters (biodiesel). The tri-organotin(IV) complexes have better catalytic activity than their di-analogs.