Organocatalyzed Birch Reduction Driven by Visible Light
作者:Justin P. Cole、Dian-Feng Chen、Max Kudisch、Ryan M. Pearson、Chern-Hooi Lim、Garret M. Miyake
DOI:10.1021/jacs.0c05899
日期:2020.8.5
The Birchreduction is a powerful synthetic methodology that uses solvated electrons to convert inert arenes to 1,4-cyclohexadienes-valuable intermediates for building molecular complexity. Birchreductions traditionally employ alkali metals dissolved in ammonia to produce a solvated electrons for the reduction of unactivated arenes such as benzene (Ered < -3.42 V vs. SCE). Photoredox catalysts have
Birch 还原是一种强大的合成方法,它使用溶剂化电子将惰性芳烃转化为 1,4-环己二烯有价值的中间体,以构建分子复杂性。桦木还原传统上使用溶解在氨中的碱金属来产生溶剂化电子,用于还原未活化的芳烃,例如苯(Ered < -3.42 V vs. SCE)。光氧化还原催化剂在高度还原应用中越来越受欢迎,但没有报道显示出足以减少苯的还原潜力。在这里,我们引入苯并苝酰亚胺作为新型有机光氧化还原催化剂,用于在环境温度下进行桦木还原,并由市售 LED 的可见光驱动。使用低催化剂负载量(<1 摩尔百分比),在完全无金属的反应中,苯和其他官能化芳烃以中等至良好的产率选择性地转化为 1,4-环己二烯。机理研究表明,这种前所未有的可见光诱导反应是通过有机光氧化还原催化剂利用两个可见光光子的能量影响单个高能化学转化的能力实现的。
Appending Diverse π-Extended Acceptors with Tetrathiafulvalene/Dithiafulvalene Donors: Multistate Redox Properties, Radical Ion Generation, and Mid-IR-Absorbing Mixed-Valence States
orbitals and influence the optoelectronic properties. The D moieties allow the formation of radical cations (D.+) and the π‐extended A moieties aid the formation of radical anions (A.−) by oxidation/reduction under ambient conditions. The molecules revealed UV/Vis/near‐IR absorption, fluorescence extending into the near‐IR region, and amphoteric electrochemical properties. Chromophores 10 and 12 show solvatochromism
Synthesis, Characterization, and Photophysical Study of Fluorescent N-substituted Benzo[ghi]perylene “Swallow Tail” Monoimides
作者:Steven J. Manning、William Bogen、Lisa A. Kelly
DOI:10.1021/jo200529p
日期:2011.8.5
characterized structurally and photophysically. Condensation of benzo[ghi]perylene-1,2-dicarboxylic anhydride in the presence of “swallow tail” alkyl amines produced fluorophores that are soluble in a range of organic solvents, highly absorbing in the near-UV (ε334 = 79 000 M–1cm–1), and fluorescent in the visible range. Photophysical behavior of the compounds was studied with steady-state and time-correlated
合成了一组N-取代的苯并per单酰亚胺(BPI)荧光团,并对其结构和光物理性质进行了表征。在“燕尾”烷基胺存在下缩合苯并per-1,2-二羧酸酐产生的荧光团可溶于多种有机溶剂,在近紫外光下高度吸收(ε334 = 79 000 M –1 cm –1),并且在可见光范围内发出荧光。使用稳态和与时间相关的单光子计数研究了化合物的光物理行为。合成的BPI表现出正的发色光发射(λem(己烷)= 469 nm; λem(乙醇)= 550 nm)作为溶剂极性的函数,在所研究的极性范围内,其激发态寿命(9.6–6.5 ns)和荧光量子产率(0.27–0.44)几乎没有变化。使用Lippert-Mataga方法分析了色度变化。在非极性烃类溶剂中,观察到紧密间隔(562 cm –1)的S 1和S 2激发态双重发射的证据。初步确定了异常S 2发射的峰值。
Liquid-Crystalline and Electron-Deficient Coronene Oligocarboxylic Esters and Imides By Twofold Benzogenic Diels–Alder Reactions on Perylenes
Alkyl esters, imides and imido-esters of coronene-tri-, -tetra- and -octacarboxylic acids are accessible by a twofold oxidative benzogenicDiels-Alderreaction. Alkyl acrylates add to perylene, and maleic alkyl imides react twice with perylene as well as with perylene-tetracarboxylic tetraesters. Coronenes substituted with a greatly variable number of electron-withdrawing substituents are thus accessible