Synthesis, structural characterization and in vitro inhibitory studies against human breast cancer of the bis-(2,6-di-tert-butylphenol)tin(iv) dichloride and its complexesElectronic supplementary information (ESI) available. CCDC 891289 (1), 891290 (2), 891291 (3), 891292 (4) and 891293 (5). For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c2dt31527k

Four new organotin( iv ) complexes of bis-(2,6-di- tert -butylphenol)tin( iv ) dichloride [( tert -Bu-) 2 (HO-Ph)] 2 SnCl 2 ( 1 ) with the heterocyclic thioamides 2-mercapto-pyrimidine (PMTH), 2-mercapto-4-methyl-pyrimidine (MPMTH), 2-mercapto-pyridine (PYTH) and 2-mercapto-benzothiazole (MBZTH), of formulae {[( tert -Bu-) 2 (HO-Ph)] 2 Sn(PMT) 2 } ( 2 ), {[( tert -Bu-) 2 (HO-Ph)] 2 Sn(MPMT) 2 } ( 3 ), {[( tert -Bu-) 2 (HO-Ph)] 2 SnCl(PYT)} ( 4 ) and {[( tert -Bu-) 2 (HO-Ph)] 2 SnCl(MBZT)} ( 5 ), have been synthesized and characterized by elemental analysis, 1 H-, 13 C-, 119 Sn-NMR, EPR, FT-IR, Raman and Mössbauer spectroscopic techniques. The crystal and molecular structures of compounds 1-5 have been determined by X-ray diffraction. The geometries around the metal center adopted in complexes 15 varied between tetrahedral in 1 , trigonal bipyramidal in 3 , 4 , 5 and distorted octahedral in 2 . Two carbon atoms from aryl groups and two chlorine atoms form a distorted tetrahedron in the case of 1 . Two carbon, two sulfur and two nitrogen atoms from thione ligands form a distorted octahedral geometry around tin( iv ) with trans-C 2 , cis-N 2 , cis-S 2 -configurations in 2 . However, in the case of 4 and 5 complexes two carbon, one sulfur, one nitrogen and one chloride atom form a distorted trigonal bipyramidal arrangement. Finally, in the case of 3 the trigonal bipyramidal geometry is achieved by two carbon, two sulfur and one nitrogen atom in a unique coordination mode of thioamides toward the tin( iv ) cation. Compounds 1-5 were tested for their in vitro cytotoxicity against the human breast adenocarcinoma (MCF-7) cell line. Compound 3 exhibits strong cytotoxic activity against MCF-7 cells (IC 50 = 0.58 ± 0.1 μM). New organotin( iv ) complexes of bis-(2,6-di- tert -butylphenol)tin( iv ) with thioamides have been synthesized, characterized and tested in vitro against MCF-7 cells.