合成了多种偶氮苯以研究其 E 和 Z 异构体在电化学还原时的行为。我们的结果表明,与中性物种相比,Z 异构体的自由基阴离子能够以显着提高的速率快速异构化为相应的 E 配置对应物。由于随后从形成的 E 自由基阴离子到中性 Z 起始材料的电子转移,整个转变在电子中是催化的;即,亚化学计量的还原物质可使整个混合物异构化。这种途径极大地提高了(光)转换的效率,同时还允许人们达到光稳定状态的组合物,该组合物不受单个偶氮苯异构体的光谱分离及其量子产率的限制。此外,用光电子转移剂激活这种自由基异构化途径使我们能够通过相同波长的光触发反向异构化方向 (Z → E) 来覆盖偶氮苯物种的固有特性,这通常会触发 E → Z 异构化。我们报告的行为似乎是普遍的,这意味着光开关的亚稳态异构体可以在还原时催化异构化为更稳定的异构体,从而允许以新的和间接的方式优化偶氮苯切换。
Oxidative Dimerization of Aromatic Amines using<i>t</i>BuOI: Entry to Unsymmetric Aromatic Azo Compounds
作者:Youhei Takeda、Sota Okumura、Satoshi Minakata
DOI:10.1002/anie.201202786
日期:2012.7.27
all the hype: An oxidative dimerization reaction of aromatic amines utilizing tert‐butyl hypoiodite (tBuOI) under mild reaction conditions leads to aromatic azocompounds (see scheme). The method allows access to unsymmetric aromatic azocompounds, which are difficult to prepare by conventional synthetic methods, in a selective manner.
A Practical Synthesis of Azobenzenes through Oxidative Dimerization of Aromatic Amines Using tert-Butyl Hypoiodite
作者:Satoshi Minakata、Youhei Takeda、Sota Okumura
DOI:10.1055/s-0032-1318388
日期:——
synthetic method of azobenzenes through oxidative dimerization of aromatic amines using a unique and cost-effective iodinating reagent is described. This new method allows for easy access to both of symmetrical and unsymmetrical azobenzenes under extremely mild conditions. A straightforward, convenient, and efficient synthetic method of azobenzenes through oxidative dimerization of aromatic amines using
unsymmetric aromatic azocompounds through an efficient and cross-selective oxidative dimerization of aromatic amines using tert-butyl hypoiodite (t-BuOI) under metal-free and mild conditions has been developed. This method was also found applicable to the synthesis of heteroaromatic azocompounds. The spectroscopic study indicates the involvement of N,N-diiodoanilines in the oxidative reaction as the key
Improving the photochemical properties of molecular photoswitches is crucial for the development of light‐responsive systems in materials and life sciences. ortho‐Fluoroazobenzenes are a new class of rationally designed photochromic azo compounds with optimized properties, such as the ability to isomerize with visiblelight only, high photoconversions, and unprecedented robust bistable character. Introducing
Novel mono- and intermolecularly substituted, cyclized, and disazo dyes have been synthesized by the reaction of 4′-dimethylamino-2,3,4,5,6-pentafluoroazobenzene and perfluoroazobenzene with bifunctional heteroatom nucleophiles, such as 1,2-benzenedithiol, 2-aminobenzenethiol, 2-aminophenol, 1,2-ethanedithiol, ethylenediamine, and 2-aminoethanol. The kinds of bifunctional nucleophiles and the reaction