To Photoredox or Not in Neutral Aqueous Solutions for Selected Benzophenone and Anthraquinone Derivatives

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• 作者：Xiting Zhang ; Jiani Ma ; David Lee Phillips
• 刊名：The Journal of Physical Chemistry Letters
• 出版年：2016
• 出版时间：December 1, 2016
• 年：2016
• 卷：7
• 期：23
• 页码：4860-4864
• 全文大小：506K
• ISSN：1948-7185

文摘

The experimental and theoretical results in neutral aqueous solutions reported here indicate that a proton-coupled electron transfer (PCET) from an alcohol C–H bond to the para-carbonyl is the initial and crucial process for the photoredox reaction of 2-(1-hydroxyethyl)-anthraquinone (HEAQ) to occur while the counterpart 3-(hydroxymethyl)-benzophenone (3-BPOH) compound displays a different PCET from an alcohol O–H bond to the carbonyl as the first step, followed by an intersystem crossing process that does not lead to the analogous photoredox, which is caused by a subtle charge-radical coupled effect between HEAQ and 3-BPOH. This can account for experimental results in the literature that HEAQ can undergo efficient photoredox but 3-BPOH does not under neutral aqueous conditions. These results have implications for the pH-dependent photochemical behavior of aromatic carbonyl compounds in aqueous media.