Synthesis, characterization and biological studies of new antimony(III) halide complexes with ω-thiocaprolactam

Abstract

Three new antimony(III) halide complexes (SbX 3, X = Cl, Br and I) with the heterocyclic thione ω-thiocaprolactam (1-azacycloheptane-2- thione, (Hthcl)) of formulae {[SbCl 2(μ 2-Cl)(Hthcl) 2] n} (1), {[(SbBr 2(μ 2-Br)(Hthcl) 2) 2]} (2) and {[(SbI 2(μ 2-I) (Hthcl) 2) 2]} (3) were synthesized from the reaction of antimony(III) halides with ω-thiocaprolactam in 1:2 stoichiometry. The complexes were characterized by elemental analysis, FT-IR spectroscopy, 1H, 13C NMR spectroscopy and Thermal Gravimetry- Differential Thermal Analysis (TG-DTA). Crystal structures of the ligand ω-thiocaprolactam and its complexes 1-3 were determined with single crystal X-ray diffraction analysis. Complexes 1-3 and ω-thiocaprolactam were evaluated for their in vitro cytotoxic activity against leiomyosarcoma (LMS) and human breast adenocarcinoma (MCF-7) tumor cell lines. Antimony complexes 1-3 exhibit strong antiproliferative activity against both cell lines tested. The higher such activity was found for 3 with IC 50 values of 0.12 ± 0.04 μM (LMS) and 0.76 ± 0.16 μM (MCF-7) which are 60 and 10 times respectively, stronger than that of cisplatin. The influence of these complexes 1-3 and ω-thiocaprolactam upon the catalytic peroxidation of linoleic acid to hyperoxolinoleic acid by the enzyme lipoxygenase (LOX) was kinetically and theoretically studied. The results were shown negligible inhibitory activity of 1-3 against LOX. © 2012 Elsevier Inc. All rights reserved.