Ultrafast Photoinduced Electron Transfer from Peroxide Dianion

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• 作者：Bryce L. Anderson ; Andrew G. Maher ; Matthew Nava ; Nazario Lopez ; Christopher C. Cummins ; Daniel G. Nocera
• 刊名：Journal of Physical Chemistry B
• 出版年：2015
• 出版时间：June 18, 2015
• 年：2015
• 卷：119
• 期：24
• 页码：7422-7429
• 全文大小：327K
• ISSN：1520-5207

文摘

The encapsulation of peroxide dianion by hexacarboxamide cryptand provides a platform for the study of electron transfer of isolated peroxide anion. Photoinitiated electron transfer (ET) between freely diffusing Ru(bpy)₃²⁺ and the peroxide dianion occurs with a rate constant of 2.0 脳 10¹⁰ M^鈥? s^鈥?. A competing electron transfer quenching pathway is observed within an ion pair. Picosecond transient spectroscopy furnishes a rate constant of 1.1 脳 10¹⁰ s^鈥? for this first-order process. A driving force dependence for the ET rate within the ion pair using a series of Ru(bpy)₃²⁺ derivatives allows for the electronic coupling and reorganization energies to be assessed. The ET reaction is nonadiabatic and dominated by a large inner-sphere reorganization energy, in accordance with that expected for the change in bond distance accompanying the conversion of peroxide dianion to superoxide anion.