Host–Guest-Induced Electron Transfer Triggers Radical-Cation Catalysis
作者:Rebecca L. Spicer、Athanasios D. Stergiou、Tom A. Young、Fernanda Duarte、Mark D. Symes、Paul J. Lusby
DOI:10.1021/jacs.9b11273
日期:2020.2.5
principle of capsule catalysis. Here we show an alternative strategy, wherein catalytic activation of otherwise inactive quinone "co-factors" by a simple Pd2L4 capsule pro-motes a range of bulk-phase, radical-cation cycloadditions. Solution electron transfer experiments and cyclic voltammetry show the cage anodically shifts the redox potential of the encapsulated quinone by a significant 1 V. Moreover, the
Photooxidizing Chromium Catalysts for Promoting Radical Cation Cycloadditions
作者:Susan M. Stevenson、Matthew P. Shores、Eric M. Ferreira
DOI:10.1002/anie.201501220
日期:2015.5.26
The photooxidizing capabilities of selected CrIII complexes for promotingradicalcationcycloadditions are described. These complexes have sufficiently long‐lived excited states to oxidize electron‐rich alkenes, thereby initiating [4+2] processes. These metal species augment the spectrum of catalysts explored in photoredox systems, as they feature unique properties that can result in differential
Diene triplets in predominantly the s-cis conformation are formed efficiently by back electron transfer to dienecationradicals in DMF and dichloromethane.
Electrochemically induced [4+2]-cycloadditions - a mechanistic interpretation of the cation radical Diels-Alder reaction based on preparative results
作者:Jiri Mlcoch、Eberhard Steckhan
DOI:10.1016/s0040-4039(00)95916-1
日期:1987.1
For the first time it was possible to induce the cation-radical Diels-Alder reactionbetween electronrich dienes and electronrich dienophiles electrochemically, thus providing a clearer view upon the mechanism of this reaction type. In contrast to common explanations it could be demonstrated that this reaction most probably takes place via the cation radical of the diene. A role selectivity towards
Synthesis, Characterization, Photophysics and Photochemistry of Pyrylogen Electron Transfer Sensitizers
作者:Edward L. Clennan、Chen Liao
DOI:10.1111/php.12174
日期:2014.3
of new dicationic sensitizers that are hybrids of pyryliumsalts and viologens has been synthesized. The electrochemical and photophysical properties of these "pyrylogen" sensitizers are reported in sufficient detail to allow rationale design of new photoinduced electron transfer reactions. The range of their reduction potentials (+0.37-+0.05 V vs SCE) coupled with their range of singlet (48-63 kcal
已经合成了一系列新的双敏增感剂,它们是吡喃鎓盐和紫精的混合物。这些“ pyrylogen”敏化剂的电化学和光物理性质已被报道得足够详细,可以合理设计新的光诱导电子转移反应。它们的还原电位范围(+ 0.37- + 0.05 V vs SCE)加上其单重态(48-63 kcal mol(-1))和三重态(48-57 kcal mol(-1))的能量范围表明是在单重态和三重态激发态下均有效的氧化剂,在热力学上能够氧化电位高达3.1 eV的底物。从容易获得的起始原料可分三步合成热原,总收率不高,为11.4-22.3%。这些敏化剂具有以下附加优点:(1)它们的自由基阳离子不会在CV时间尺度上与氧气发生反应,从而绕开了在氮气或氩气下进行反应的需要;(2)在413至523 nm之间的长波长吸收远超出了大多数底物的竞争性吸收范围引起问题。这些新的敏化剂会与水发生反应,需要特殊的预防措施才能在干燥的反应环境中运行。