Inorganic and Analytical Chemistry, Department of Chemistry, University of Ioannina, 45110, Ioannina, Greece.
Dalton Trans. 2009 Dec 21(47):10446-56. doi: 10.1039/b909587j. Epub 2009 Oct 13.
The reactions of tetrachloroauric(III) acid (HAuCl4) with the thioamides; 2-mercapto-benzothiazole (mbztH) and 5-ethoxy-2-mercapto-benzimidazole (EtmbzimH) lead to the desulfuration of the ligands and the formation of the ionic complexes {[AuCl4]- [bztH2]+} (1), and {[AuCl4]- [EtbzimH2]+ (H2O)} (2) (where bztH2+ and EtbzimH2+ are the desulfurated cations of the starting ligands). The reaction of HAuCl4 with 2-mercapto-nicotinic acid (mnaH2), however results in the formation of 2-sulfonate-nicotininc acid (C6H5NO5S) (3) with the simultaneous oxidation of the sulfur atom. On the other hand, the reactions of the gold(I) complex [Au(tpp)Cl] (4) (tpp = triphenylphosphine (Ph3P)) with the thioamides; 2-mercapto-thiazolidine (mtzdH), 2-mercapto-benzothiazole (mbztH) and 5-chloro-2-mercapto-benzothiazole (ClmbztH) in the presence of potassium hydroxide resulted in the formation of the gold(I) complexes of formulae [Au(tpp)(mtzd)] (5), [Au(tpp)(mbzt)] (6) and [Au(tpp)(Clmbzt)] (7) without ligand desulfuration. All complexes have been characterized by elemental analysis, FT-IR, far-FT-IR,1H-NMR, spectroscopic techniques and X-Ray crystallography. The electrochemical behavior of 1, 2 and 4-7 complexes and the ligands EtmbzimH, mbztH and mnaH2 was also studied in acetonitrile and DMF using cyclic voltammetry. The results are in support of a mechanism of desulfuration of the ligands by Au(III), involving a first oxidation of S to -SO3-, followed by a C-S bond cleavage. This is also supported by PM6 calculations of bond dissociation energies of the various compounds involved. Complexes 1, 2 and 4-7 were tested for in vitro cytotoxicity against leiomyosarcoma cells and the results are discussed in relation with the geometry of the complexes and compared with those of cisplatin and other metals. Complexes 1 and 5 showed higher activity than that of cisplatin, while HAuCl4 was inactive against sarcoma cells.
四氯金(III)酸（HAuCl4）与硫代酰胺反应；2-巯基苯并噻唑（mbztH）和 5-乙氧基-2-巯基苯并咪唑（EtmbzimH）导致配体脱硫，并形成离子配合物{[AuCl4]-[bztH2]+}（1）和{[AuCl4]-[EtbzimH2]+（H2O）}（2）（其中 bztH2+和 EtbzimH2+是起始配体的脱硫阳离子）。然而，HAuCl4与 2-巯基烟酸（mnaH2）的反应导致 2-磺酸盐烟酸（C6H5NO5S）（3）的形成，同时硫原子被氧化。另一方面，金（I）配合物[Au（tpp）Cl]（4）（tpp=三苯基膦（Ph3P））与硫代酰胺；2-巯基噻唑烷（mtzdH），2-巯基苯并噻唑（mbztH）和 5-氯-2-巯基苯并噻唑（ClmbztH）在氢氧化钾存在下反应，形成金（I）配合物的化学式[Au（tpp）（mtzd）]（5），[Au（tpp）（mbzt）]（6）和[Au（tpp）（Clmbzt）]（7）没有配体脱硫。所有配合物均通过元素分析、FT-IR、远 FT-IR、1H-NMR、光谱技术和 X 射线晶体学进行了表征。还使用循环伏安法在乙腈和 DMF 中研究了 1、2 和 4-7 配合物以及配体 EtmbzimH、mbztH 和 mnaH2 的电化学行为。结果支持配体通过 Au（III）脱硫的机制，涉及 S 到 -SO3-的首次氧化，然后是 C-S 键的断裂。这也得到了涉及的各种化合物的键离解能的 PM6 计算的支持。测试了配合物 1、2 和 4-7 对平滑肌肉瘤细胞的体外细胞毒性，并根据配合物的几何形状进行了讨论，并与顺铂和其他金属进行了比较。配合物 1 和 5 的活性高于顺铂，而 HAuCl4 对肉瘤细胞无活性。
