Optically Gated Dissociation of a Heptazinyl Radical Liberates H• through a Reactive πσ* State

IF 3.7 Q2 CHEMISTRY, PHYSICAL
Liam Wrigley, Doyk Hwang, Sebastian V. Pios, Cody W. Schlenker
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引用次数: 0

Abstract

Using trianisole heptazine (TAHz) as a monomeric analogue for carbon nitride, we performed ultrafast pump–photolysis–probe transient absorption (TA) spectroscopy on the intermediate TAHzH heptazinyl radical produced from an excited state PCET reaction with 4-methoxyphenol (MeOPhOH). Our results demonstrate an optically gated photolysis that releases H and regenerates ground state TAHz. The TAHzH radical signature at 520 nm had a lifetime of 7.0 ps, and its photodissociation by the photolysis pulse is clearly demonstrated by the ground state bleach recovery of the closed-shell neutral TAHz. This behavior has been previously predicted as evidence of a dissociative πσ* state. For the first time, we experimentally demonstrate photolysis of the TAHzH heptazinyl radical through a repulsive πσ* state. This is a critical feature of the proposed reaction mechanisms involving water oxidation and CO2 reduction.

Abstract Image

七嗪基自由基的光控解离通过反应πσ*态释放 H-
我们利用三苯甲醚庚嗪(TAHz)作为氮化碳的单体类似物,对激发态 PCET 与 4-甲氧基苯酚(MeOPhOH)反应产生的中间体 TAHzH- 庚嗪自由基进行了超快泵光解-探针瞬态吸收(TA)光谱分析。我们的研究结果表明了一种光学门控光解作用,它释放出 H-,并再生出基态 TAHz。在 520 纳米波长下,TAHzH- 自由基的寿命为 7.0 ps,其在光解脉冲下的光解离可通过闭壳中性 TAHz 的基态漂白恢复清楚地证明。这种行为以前曾被预测为解离πσ*态的证据。我们首次在实验中证明了 TAHzH- 庚嗪基通过排斥πσ*态发生光解。这是涉及水氧化和二氧化碳还原的拟议反应机制的一个关键特征。
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来源期刊
CiteScore
3.70
自引率
0.00%
发文量
0
期刊介绍: ACS Physical Chemistry Au is an open access journal which publishes original fundamental and applied research on all aspects of physical chemistry. The journal publishes new and original experimental computational and theoretical research of interest to physical chemists biophysical chemists chemical physicists physicists material scientists and engineers. An essential criterion for acceptance is that the manuscript provides new physical insight or develops new tools and methods of general interest. Some major topical areas include:Molecules Clusters and Aerosols; Biophysics Biomaterials Liquids and Soft Matter; Energy Materials and Catalysis
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