Different Nature of the Interactions between Anions and HAT(CN)6: From Reversible Anion鈭捪€ Complexes to Irreversible Electron-Transfer Processes (HAT(CN)6 = 1,4,5,8,9,12-Hexaazat

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• 作者：Gemma Aragay ; Antonio Frontera ; Vega Lloveras ; Jos茅 Vidal-Gancedo ; Pablo Ballester
• 刊名：The Journal of the American Chemical Society
• 出版年：2013
• 出版时间：February 20, 2013
• 年：2013
• 卷：135
• 期：7
• 页码：2620-2627
• 全文大小：322K
• 年卷期：v.135,no.7(February 20, 2013)
• ISSN：1520-5126

文摘

We report experimental evidence indicating that the nature of the interaction established between HAT(CN)₆, a well-known strong electron acceptor aromatic compound, with mono- or polyatomic anions switches from the almost exclusive formation of reversible anion鈭捪€ complexes, featuring a markedly charge transfer (CT) or formal electron-transfer (ET) character, to the quantitative and irreversible net production of the anion radical [HAT(CN)₆]^{鈥⑩€?/sup> and the dianion [HAT(CN)₆]2鈥?/sup> species. The preferred mode of interaction is dictated by the electron donor abilities of the interacting anion. Thus, weaker Lewis basic anions such as Br鈥?/sup> or I鈥?/sup> are prone to form mainly anion鈭捪€ complexes. On the contrary, stronger Lewis basic F鈥?/sup> or 鈥?/sup>OH anions display a net ET process. The ET process can be either thermal or photoinduced depending on the HOMO/LUMO energy difference between the electron donor (anion) and the electron acceptor (HAT(CN)₆). These ET processes possibly involve the intermediacy of anion鈭捪€ complexes having strong ET character and producing an ion-pair radical complex. We hypothesize that the irreversible dissociation of the pair of radicals forming the solvent-caged complex is caused by the reduced stability (high reactivity) of the radical resulting from the anion.}