Reisner Erwin, Arion Vladimir B, Eichinger Anna, Kandler Norbert, Giester Gerald, Pombeiro Armando J L, Keppler Bernhard K
Institute of Inorganic Chemistry-Bioinorganic, Environmental and Radiochemistry, University of Vienna, Währingerstrasse 42, A-1090 Vienna, Austria.
Inorg Chem. 2005 Sep 19;44(19):6704-16. doi: 10.1021/ic0503737.
A series of mixed chloro-azole ruthenium complexes with potential antitumor activity, viz., mer-[RuIIICl3(azole)3] (B), trans-[RuIIICl2(azole)4]Cl (C), trans-[RuIICl2(azole)4] (D), and RuII(azole)62 (E), where azole = 1-butylimidazole (1), imidazole (2), benzimidazole (3), 1-methyl-1,2,4-triazole (4), 4-methylpyrazole (5), 1,2,4-triazole (6), pyrazole (7), and indazole (8), have been prepared as a further development of anticancer drugs with the general formula [RuCl4(azole)2]- (A). These compounds were characterized by elemental analysis, IR spectroscopy, electronic spectra, electrospray mass spectrometry, and X-ray crystallography. The electrochemical behavior has been studied in detail in DMF, DMSO, and aqueous media using cyclic voltammetry, square wave voltammetry, and controlled potential electrolysis. Compounds B and a number of C complexes exhibit one RuIII/RuII reduction, followed, at a sufficiently long time scale, by metal dechlorination on solvolysis. The redox potential values in organic media agree with those predicted by Lever's parametrization method, and the yet unknown EL parameters were estimated for 1 (EL = 0.06 V), 3 (EL = 0.10 V), 4 (EL = 0.17 V), and 5 (EL = 0.18 V). The EL values for the azole ligands 1-8 correlate linearly with their basicity (pK(a) value of the corresponding azolium acid H2L+). In addition, a logarithmic dependence between the homogeneous rate constants for the reductively induced stepwise replacement of chloro ligands by solvent molecules and the RuIII/RuII redox potentials was observed. Lower E(1/2) values (higher net electron donor character of the ligands) result in enhanced kinetic rate constants of solvolysis upon reduction. The effect of the net charge on the RuIII/RuII redox potentials in water is tentatively explained by the application of the Born equation. In addition, the pH-dependent electrochemical behavior of trans-[RuCl2(1,2,4-triazole)4]Cl is discussed.
一系列具有潜在抗肿瘤活性的氯代唑钌混合配合物，即顺式-[RuIIICl3(唑)3] (B)、反式-[RuIIICl2(唑)4]Cl (C)、反式-[RuIICl2(唑)4] (D) 和 RuII(唑)62 (E)，其中唑 = 1-丁基咪唑 (1)、咪唑 (2)、苯并咪唑 (3)、1-甲基-1,2,4-三唑 (4)、4-甲基吡唑 (5)、1,2,4-三唑 (6)、吡唑 (7) 和吲唑 (8)，已作为通式为 [RuCl4(唑)2]- (A) 的抗癌药物的进一步发展而制备。这些化合物通过元素分析、红外光谱、电子光谱、电喷雾质谱和 X 射线晶体学进行了表征。使用循环伏安法、方波伏安法和控制电位电解法在 DMF、DMSO 和水性介质中详细研究了电化学行为。化合物 B 和许多 C 配合物表现出一次 RuIII/RuII 还原，随后在足够长的时间尺度上，在溶剂解时发生金属脱氯。有机介质中的氧化还原电位值与 Lever 参数化方法预测的值一致，并估计了 1 (EL = 0.06 V)、3 (EL = 0.10 V)、4 (EL = 0.17 V) 和 5 (EL = 0.18 V) 的未知 EL 参数。唑配体 1-8 的 EL 值与其碱性（相应唑鎓酸 H2L+ 的 pK(a) 值）呈线性相关。此外，观察到还原诱导的氯配体被溶剂分子逐步取代的均相速率常数与 RuIII/RuII 氧化还原电位之间存在对数依赖性。较低的 E(1/2) 值（配体的净电子供体特性更高）导致还原时溶剂解的动力学速率常数增加。通过应用玻恩方程初步解释了净电荷对水中 RuIII/RuII 氧化还原电位的影响。此外，还讨论了反式-[RuCl2(1,2,4-三唑)4]Cl 的 pH 依赖性电化学行为。
