How is the water molecule activated on metalloporphyrins? Oxygenation of substrates induced through one-photon/two-electron conversion in artificial photosynthesis by visible light.
How is the water molecule activated on metalloporphyrins? Oxygenation of substrates induced through one-photon/two-electron conversion in artificial photosynthesis by visible light.
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金属卟啉上的水分子是如何被激活的？
DOI：
10.1039/c1fd00069a
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发表时间：
2012
影响因子：
3.4
通讯作者：
H. Inoue
中科院分区：
文献类型：
--
作者：
T. Shimada;Akihiro Kumagai;Shigeaki Funyu;S. Takagi;D. Masui;Y. Nabetani;H. Tachibana;D. Tryk;H. Inoue
研究了以水为电子供体和氧原子供体，共配位tetra(2，4，6-trimethyl)phenylporphyrinatoruthenium(II)(Ru(II)TMP(CO))敏化的高效选择性光化学环氧化反应机理。反应混合物的稳态光照表明，在中性条件下形成了Ru(II)TMP(CO)阳离子自由基，该自由基被氢氧离子有效地捕获以再生起始敏化剂。通过激光闪光光解实验，清楚地观察到Ru(II)TMP(CO)的三重态激发态以阳离子自由基的形成为主要过程。在完全不同的延迟时间范围内检测到了四种不同的瞬变：Ru(II)TMP(CO)的激发三重态[延迟时间区间20微秒]，Ru(II)TMP(CO)(CH3CN)的阳离子自由基[20-50微秒]，羟基配位中间体[I][50-200微秒]，以及环己烷连接的中间体[II][200微秒-8毫秒]。反应机理为：敏化剂的三重态激发生成RuTMP(CO)阳离子自由基，然后羟基离子攻击生成羟基配位的Ru-卟啉(中间体[I])，再与环己烯反应生成中间体[II]。仔细分析了连续过程中每一步的动力学过程，并测定了它们的速率常数。光化学环氧化反应揭示的单光子辐照双电子氧化水被认为是解决人工光合作用中水氧化瓶颈的较有前途的候选方法之一。
The reaction mechanism of the highly efficient (phi = 0.60), selective photochemical epoxidation of alkenes sensitized by CO-coordinated tetra(2,4,6-trimethyl)phenylporphyrinatoruthenium(II) (Ru(II)TMP(CO)), with water acting both as an electron and oxygen atom donor, was investigated. The steady-state light irradiation of the reaction mixture indicated the formation of the Ru(II)TMP (CO) cation radical under neutral conditions, which was effectively trapped by an hydroxide ion to regenerate the starting sensitizer. By means of a laser flash photolysis experiment, the formation of the cation radical as the primary process from the triplet excited state of Ru(II)TMP(CO) was clearly observed. Four kinds of transients were detected in completely different ranges of the delay time: the excited triplet state of Ru(II)TMP(CO) [delay time region <20 micros], the cation radical of Ru(II)TMP(CO)(CH3CN) [20-50 micros], the hydroxyl-coordinated Intermediate [I] [50-200 micros], and the cyclohexane-attached Intermediate [II] [200 micros-8 ms]. A reaction mechanism was revealed that involves RuTMP(CO) cation radical formation from the triplet excited state of the sensitizer, followed by attack of an hydroxide ion to form an hydroxyl-coordinated Ru-porphyrin (Intermediate [I]) and subsequent reaction with cyclohexene to form Intermediate [II]. The kinetics for each step of the successive processes was carefully analyzed and their rate constants were determined. The two-electron oxidation of water by one-photon irradiation, as revealed in the photochemical epoxidation, is proposed to be one of the more promising candidates to get through the bottleneck of water oxidation in artificial photosynthesis.
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Takayuki Kitamura、Yuji Wada、KeiMurakoshi、Mitsuhiro Kusaba、Nobuaki Nakashima、Akito Ishida、Tetsuro Majima、Setsuo Takamuku、Tohru Akano、Shozo Yanagida：“Pe光敏化水一电子氧化为羟基自由基的机理研究
DOI：
--
发表时间：
--
期刊：
影响因子：
--
作者：
通讯作者：
--
影响因子：
1.6
作者：
Yoshida, Masaki;Masaoka, Shigeyuki;Sakai, Ken
通讯作者：
Sakai, Ken
影响因子：
56.9
作者：
Yin, Qiushi;Tan, Jeffrey Miles;Hill, Craig L.
通讯作者：
Hill, Craig L.
影响因子：
15
作者：
Funyu, S;Isobe, T;Inoue, H
通讯作者：
Inoue, H
影响因子：
1.6
作者：
Masaoka, Shigeyuki;Sakai, Ken
通讯作者：
Sakai, Ken