Bismuth(III) bromide-thioamide complexes: synthesis, characterization and cytotoxic properties

Abstract

Abstract New bismuth(III) bromine compounds of the heterocyclic thioamides were prepared and structurally characterized. The reaction of heterocyclic thioamides with bismuth(III) bromide resulted in the formation of the {[BiBr2(μ2-Br)(MMI)2]2·CH3COCH3·H2O} (1), {[BiBr2(MBZIM)4]·Br·2H2O} (2), {[BiBr2(μ2-Br)(tHPMT)2]2·CH3CN} (3), {[BiBr2(μ2-Br)(PYT)2]2·CH3CN} (4) and {[BiBr2(μ2-Br)(MBZT)2]2 2CH3OH} (5) complexes (MMI: 2-mercapto-1-methylimidazole, MBZIM: 2-mercaptobenzimidazole, tHPMT: 2-mercapto-3,4,5,6-tetrahydro-pyrimidine, PYT: 2-mercaptopyridine and MBZT: 2-mercaptobenzothiazole). The complexes 1–5 were characterized by melting point (m.p.), elemental analysis (e.a.), molar conductivity, Fourier-transform infrared (FT-IR), Fourier-transform Raman (FT-Raman), nuclear magnetic resonance (1H and 13CNMR) spectroscopy, UV-Vis spectroscopy and thermogravimetric-differential thermal analysis (TG-DTA). The molecular structures of 1–5 were determined by single-crystal X-ray diffraction. Complex 2 is a first ionic monomuclear octahedral bismuth(III) bromide, while the complexes 1, 3–5 are the first examples of dinuclear bismuth(III) bromide derivatives. Complexes 1–5 were evaluated in terms of their in vitro cytotoxic activity against human adenocarcinoma breast (MCF-7) and cervix (HeLa) cells. The toxicity on normal human fetal lung fibroblast cells (MRC-5) was also evaluated. Moreover, the complexes 1–5 and free heterocyclic thioamide ligands were studied upon the catalytic peroxidation of the linoleic acid by the enzyme lipoxygenase (LOX).