Interaction of antimony(III) chloride with thiourea, 2-mercapto-5-methyl-benzimidazole, 3-methyl-2-mercaptobenzothiazole, 2-mercaptopyrimidine, and 2-mercaptopyridine

Abstract

New antimony(III) chloride complexes with heterocyclic thioamides, thiourea (TU), 2-mercapto-5-methyl-benzimidazole (MMBZIM), 3-methyl-2-mercaptobenzothiazole (MMBZT), 2-mercaptopyrimidine (PMT), 2-mercaptopyridine (PYT) of formulae [SbCl3(TU)2] (1), [SbCl3(MMBZIM)2] (2), [SbCl3(MMBZT)2] (3), [SbCl3(PMT)2] (4), [SbCl3(μ 2-S)(PYT)2] (5) were synthesized and characterized by elemental analysis, FT-IR and FT-Raman spectroscopies, and TG-DTA analysis. The crystal structure of 5 was also determined by X-ray diffraction. [C10H10Cl3N2S2Sb] (5) crystallizes in space group C2/c, with a = 25.0169(10) Å, b = 9.7952(3) Å, c = 12.9329(5) Å, β = 109.702(4)°, and Z = 8. Crystals of 5 grown from acetonitrile solutions adopt a square-pyramidal geometry. The equatorial plane is formed by three chlorides and one sulfur atom from the thione ligand while the second sulfur is axial. The complexes were evaluated for their biological activities and compared with [SbCl3(MMI)2] (6) (MMI = 2-mercapto-1-methylimidazole) and other isostructural ones. The complexes showed moderate cytostatic activity against murine leukemia cells (L1210), murine mammary carcinoma cells (FM3A), human T-lymphocyte (Molt4/C8, CEM), and human cervix carcinoma (HeLa) cells. The chloro and iodo derivatives show better cytostatic activity than the bromo ones.