Organotin(IV) derivatives of o-isobutyl carbonodithioate: Synthesis, spectroscopic characterization, X-ray structure, HOMO/LUMO and in vitro biological activities

A series of organotin(IV) complexes have been synthesized by reacting potassium 0-isobutyl carbonodithioate with di-and triorganotin halides in methanol under stirring conditions. The newly synthesized complexes have been characterized by elemental analysis, FT-IR, NMR (H-1 and C-13) and X-ray crystallography. The FT-IR results show that the ligand acts as bidentate in complexes 1-3 and monodentate in complexes 4 and 5, which were also confirmed by theoretical calculations. The NMR data reveal four and six coordinated geometries in solution. A HOMO-LUMO study shows that all the complexes are stable. Biological screenings demonstrate that, with a few exceptions, all the complexes show significant activity against various bacterial and fungal strains. The synthesized complexes were also found to be effective antioxidants of the 2,2-diphenyl-l-picrylhydrazyl radical (DPPH). All the complexes have been assayed for antileishmanial activity in vitro and found some promising results. The UV-Vis studies confirmed that the ligand and its complexes bind to DNA via intercalative interactions, resulting in hypochromism and minor red shifts. (C) 2015 Elsevier Ltd. All rights reserved.