Hydrolysis of an organometallic cation, [Ru(η6-p-cym)(H2O)3]2+ (p-cym = 1-isopropyl-4-methylbenzene), in the presence of 0.20 M KNO3 or KCl as supporting electrolyte was studied in detail with the combined use of pH-potentiometry, 1H-NMR, UV-VIS and ESI-TOF-MS. Stoichiometry and stability constants of chlorido, hydroxido and mixed chlorido-hydroxido complexes formed in aqueous solution have been determined. At pH < 4.0 where hydrolysis of [Ru(η6-p-cym)(H2O)3]2+ is negligible with increasing chloride ion concentration two chlorido complexes, [Ru(η6-p-cym)(H2O)2Cl]+ and [Ru(η6-p-cym)}2(μ2-Cl)3]+, are detectable. At pH > 5.0, in chloride ion free samples the exclusive formation of [Ru(η6-p-cym)}2(μ2-OH)3]+ is found. However, if chloride ion is present (in the range 0â3.50 M) novel mixed chlorido-hydroxido species, [Ru(η6-p-cym)}2(μ2-OH)2(μ2-Cl)]+ and [Ru(η6-p-cym)}2(μ2-OH)(μ2-Cl)2]+ can also be identified at pH > 4.0. The results obtained in this study may help in rationalizing the solution behaviour of half-sandwich [Ru(η6-p-cym)(XY)Z] type complexes which, after dissociation of both the monodentate Z and the chelating XY, are capable of yielding the free aqua species [Ru(η6-p-cym)(H2O)3]2+. Our results demonstrate that different chloride ion concentrations can influence the speciation in the acidic pH range but at biologically relevant conditions (pH = 7.4, cClâ = 0.16 M) and at cM = 1 μM [Ru(η6-p-cym)}2(μ2-OH)3]+ is predominant in the absence of any coordinating ligands.
在 0.20 M
KNO3 或 KCl 作为支持电解质的情况下,结合使用 pH 电位计、1H-NMR、UV-VIS 和 ESI-TOF-MS 对有机
金属阳离子 [Ru(δ-6-p-cym)(
H2O)3]2+(p-cym = 1-异丙基-4-甲基苯)的
水解进行了详细研究。测定了在
水溶液中形成的
氯复合物、羟复合物和
氯羟混合复合物的
化学计量和稳定常数。当 pH 值小于 4.0 时,随着
氯离子浓度的增加,[Ru(δ-6-p-cym)( )3]2+ 的
水解作用可以忽略不计,这时可以检测到两种
氯复合物,即 [Ru(δ-6-p-cym)( )2Cl]+ 和 [Ru(δ-6-p-cym)}2(δ2-Cl)3]+。当 pH 值大于 5.0 时,在不含
氯离子的样品中只形成[Ru(δ-6-p-ym)}2(δ2-OH)3]+。然而,如果存在
氯离子(在 0â3.50 M 的范围内),在 pH 值大于 4.0 时,也能识别出[Ru(δ-6-p-cym)}2(δ-2-OH)2(δ-2-Cl)]+ 和[Ru(δ-6-p-cym)}2(δ-2-OH)(δ-2-Cl)2]+ 这两种新颖的
氯羟混合物种。本研究获得的结果可能有助于合理解释半夹心[Ru(δ-6-p-cym)(XY)Z]型配合物的溶液行为,这些配合物在单价 Z 和螯合 XY 解离后,能够产生游离
水生物种[Ru(δ-6-p-cym)( )3]2+。我们的研究结果表明,在酸性 pH 值范围内,不同的
氯离子浓度会影响其分型,但在
生物相关条件下(pH = 7.4,cClâ = 0.16 M)和 cM = 1 ¼M 时,在没有任何配位
配体的情况下,[Ru(δ-6-p-cym)}2(δ-¼2-OH)3]+ 是主要的。