Synthesis, structural characterization and in vitro cytotoxicity of organotin(IV) derivatives of heterocyclic thioamides, 2-mercaptobenzothiazole, 5-chloro-2-mercaptobenzothiazole, 3-methyl-2-mercaptobenzothiazole and 2-mercaptonicotinic acid

Abstract

Five new organotin(IV) molecules with the heterocyclic thioamides; 2-mercaptobenzothiazole (Hmbzt), 5-chloro-2-mercaptobenzothiazole (Hcmbzt), 3-methyl-2-mercaptobenzothiazole (mmbzt) and 2-mercaptonicotinic acid (H 2mna) of formulae [( n-C 4H 9) 2Sn(mbzt) 2] ( 1), [(C 6H 5) 2Sn(mbzt) 2] ( 2), {(CH 3) 2Sn(cmbzt) 2] ·1.7(H 2O)} ( 3), [( n-C 4H 9) 2SnCl 2(mmbzt) 2 ·(CH 2Cl 2)] ( 4) and {[(C 6H 5) 3Sn] 2(mna) ·[(CH 3) 2CO]} ( 5) have been synthesized and characterized by elemental analysis, 1H-, 13C-NMR, FT-IR and Mössbauer spectroscopic techniques. Crystal structures of molecules 1, 3 and 5 have been determined by X-ray diffraction at 173(1) K ( 1 and 5) and 293(2) K ( 3). Compound 1 C 22H 26N 2S 4Sn, is monoclinic, space group C2/c, a=44.018(2), b=8.8864(5), c=12.8633(7) Å, β=104.195(5)°, Z=8. Compound 3 is also monoclinic, space group P2 1/ c and a=17.128(2) Å, b=17.919(2) Å, c=7.3580(10) Å, β=98.290(10)°, Z=4. In both molecules 1 and 3, two carbon atoms from aryl groups, 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. Compound 5 C 45H 39NO 3SSn 2 is monoclinic, space group P2 1/ n, a=9.1148(2) Å, b=29.2819(6), c=15.5556(4) Å, β=106.2851(9)°, Z=4. Complex 5 contains two [(C 6H 5) 3Sn(IV)] moieties linked by a double deprotonated 2-mercaptonicotinic acid (H 2mna). Both tin(IV) ions are five coordinated. This complex is the an example of a pentacoordinated Ph 3SnXY system with an axial-equatorial arrangement of the phenyl groups at Sn(1) atom. Compounds 1, 3 and 5 were tested for in vitro cytotoxicity against the cancer cell line of sarcoma cells (mesenchymal tissue) from the Wistar rat, polycyclic aromatic hydrocarbons (benzo[ a]pyrene) carcinogenesis. Compound 5 exhibits strong cytotoxic activity, while complexes 1 and 3 show less cytotoxic activity.