Gold(I)-induced chelate ring-opening of palladium(II) and platinum(II) triphos complexes
作者:Paloma Sevillano、Abraha Habtemariam、Simon Parsons、Alfonso Castiñeiras、M. Esther García、Peter J. Sadler
DOI:10.1039/a903775f
日期:——
The complexes [M(triphos)Cl]Cl [triphos = PhP(CH2CH2PPh2)2; M = Pd (1), M = Pt (2)] undergo ring-opening reactions with Au(I) to give [MAu(triphos)Cl3] [M = Pd (3), M = Pt (4) ]. In these mixed metal complexes, triphos acts as a bidentate ligand for M and the third phosphorus atom is coordinated to Au(I) with a linear geometry. Complexes 1–4 were characterised by microanalysis, FAB mass spectrometry, IR, NMR (31P and 195Pt) spectroscopies and conductivity measurements. Complexes 2–4 were also characterised by X-ray crystallography. [Pt(triphos)Cl]Cl, 2, is monoclinic, space group P21/n, with square-planar geometry. The Pt–Pcentral bond distance (2.207 Å) is shorter than the other two Pt–P distances (2.312 and 2.315 Å). [PdAu(triphos)Cl3], 3, is also monoclinic (space group P21/n), with square-planar Pd(II) and linear Au(I) (P–Au–Cl 177.73°), and has a similar structure to complex 4, [PtAu(triphos)Cl3] (monoclinic, space group I2/a). The thiolate S of the tripeptide glutathione (GSH) and N-acetyl-L-cysteine binds to [Pt(triphos)]2+ giving adducts with high aqueous solubility. In the presence of Au(I), 5′-GMP displaced glutathione from [Pt(triphos)(GS)]+ to form two adducts. Both GSH and N-acetyl-L-cysteine readily extracted Au(I) from complex 4, [PtAu(triphos)Cl3], to give complex 2, [Pt(triphos)Cl]Cl, and the Au(I) thiolate. Since chloride and thiolates would be strong competitors to DNA binding, proteins could be possible target sites for these complexes.
复合物 [M(triphos)Cl]Cl [triphos = PhP(CH2CH2PPh2)2; M = Pd (1), M = Pt (2)] 与 Au(I) 发生开环反应,生成 [MAu(triphos)Cl3] [M = Pd (3), M = Pt (4) ]。在这些混合金属配合物中,三磷作为 M 的双齿配体,第三个磷原子以线性几何形状配位到 Au(I)。络合物 1-4 的表征方法包括显微分析、FAB 质谱、红外光谱、核磁共振(31P 和 195Pt)光谱和电导率测量。络合物 2-4 还通过 X 射线晶体学进行了表征。[Pt(triphos)Cl]Cl,2,为单斜晶系,空间群为 P21/n,几何形状为正方形。铂-中心键距离(2.207 Å)比其他两个铂-中心键距离(2.312 和 2.315 Å)短。[PdAu(triphos)Cl3],3,也是单斜(空间群 P21/n),具有方形 Pd(II)和线性 Au(I)(P-Au-Cl 177.73°),其结构与复合物 4 [PtAu(triphos)Cl3](单斜,空间群 I2/a)相似。三肽谷胱甘肽(GSH)和 N-乙酰-L-半胱氨酸的硫酸盐 S 与[Pt(triphos)]2+ 结合,产生具有高水溶性的加合物。在 Au(I)存在的情况下,5′-GMP 将谷胱甘肽从 [Pt(triphos)(GS)]+ 中置换出来,形成两种加合物。谷胱甘肽和 N-乙酰-L-半胱氨酸都很容易从络合物 4 [PtAu(triphos)Cl3]中提取出 Au(I),得到络合物 2 [Pt(triphos)Cl]Cl,以及 Au(I)硫酸盐。由于氯化物和硫酸盐是 DNA 结合的强竞争者,蛋白质可能是这些复合物的目标位点。