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

Abstract

Three new antimony(III) halide complexes (SbX3, X = Cl, Br and I) with the heterocyclic thione omega-thiocaprolactam (1-azacycloheptane-2-thione, (Hthcl)) of formulae {[SbCl2(mu(2)-Cl)(Hthcl)(2)](n)} (1), {[(SbBr2(mu(2)-Br)(Hthcl)(2))(2)]} (2) and {[(Sbl(2)(mu(2)-I)(Hthcl)(2))(2)]} (3) were synthesized from the reaction of antimony(III) halides with w-thiocaprolactam in 1:2 stoichiometry. The complexes were characterized by elemental analysis, FT-IR spectroscopy, H-1, C-13 NMR spectroscopy and Thermal Gravimetry-Differential Thermal Analysis (TG-DTA). Crystal structures of the ligand w-thiocaprolactam and its complexes 1-3 were determined with single crystal X-ray diffraction analysis. Complexes 1-3 and w-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 IC50 values of 0.12 +/- 0.04 mu M (LMS) and 0.76 +/- 0.16 mu M (MCF-7) which are 60 and 10 times respectively, stronger than that of cisplatin. The influence of these complexes 1-3 and w-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. (C) 2012 Elsevier Inc. All rights reserved.