Two-Electron Oxidation of Deoxyguanosine by a Ru(III) Complex without Involving Oxygen Molecules through Disproportionation

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• 作者：Sunhee Choi ; DaWeon Ryu ; Joseph G. DellaRocca ; Matthew W. Wolf ; Justin A. Bogart
• 刊名：Inorganic Chemistry
• 出版年：2011
• 出版时间：July 18, 2011
• 年：2011
• 卷：50
• 期：14
• 页码：6567-6574
• 全文大小：999K
• 年卷期：v.50,no.14(July 18, 2011)
• ISSN：1520-510X

文摘

Among the many mechanisms for the oxidation of guanine derivatives (G) assisted by transition metals, Ru^III and Pt^IV metal ions share basically the same principle. Both Ru^III- and Pt^IV-bound G have highly positively polarized C8鈥揌鈥檚 that are susceptible to deprotonation by OH^{鈥?/sup>, and both undergo two-electron redox reactions. The main difference is that, unlike PtIV, RuIII is thought to require O₂ to undergo such a reaction. In this study, however, we report that [RuIII(NH₃)₅(dGuo)] (dGuo = deoxyguanosine) yields cyclic-5鈥?O-C8-dGuo (a two-electron G oxidized product, cyclic-dGuo) without O₂. In the presence of O₂, 8-oxo-dGuo and cyclic-dGuo were observed. Both [RuII(NH₃)₅(dGuo)] and cyclic-dGuo were produced from [RuIII(NH₃)₅(dGuo)] accelerated by [OH鈥?/sup>]. We propose that [RuIII(NH₃)₅(dGuo)] disproportionates to [RuII(NH₃)₅(dGuo)] and [RuIV(NH₃)₄(NH₂鈥?/sup>)(dGuo)], followed by a 5鈥?OH attack on C8 in [RuIV(NH₃)₄(NH₂鈥?/sup>)(dGuo)] to initiate an intramolecular two-electron transfer from dGuo to RuIV, generating cyclic-dGuo and RuII without involving O₂.}