Construction of Redox-type Photochromic Systems Based on Photoinduced Electron Transfer Reactions in Crystalline State

该研究项目旨在构建基于晶态电子供体-受体复合物的光诱导电子转移反应的新型氧化还原型光致变色体系。为了实现这一想法，有必要开发一种具有双稳定性的新型氧化还原分子。因此，氧化还原对被设计为在电子转移时经历可逆的C-C键形成和裂解。研究从检查互变六苯乙烷衍生物1和双（三芳基甲烷）染料2开始。发现它们构成动态可逆的氧化还原对，在电子转移时表现出生动的颜色变化和剧烈的结构变化。他们无疑是目前目的的有希望的候选人。然而不幸的是，用多种电子给体获得1的CT晶体的尝试都没有成功，阻止了我最初的提议的实现。接下来，研究具有二氰基乙烯基部分的联苯型电子受体。发现2,2'-二取代衍生物在双电子还原时形成C-C键。通过结合还原产物的进一步异构化，后一个系统构成了具有“写保护”选项的新型电致变色系统的原型。

The research project is intended to construct the novel redox-type photochromic systems based on the photoinduced electron transfer reactions of electron-donor-acceptor complexes in the crystalline state. In order to realize such an idea it is essential to develop a new type of redox molecules exhibiting bistability. Thus, the redox pairs were designed so as to undergo reversible C-C bond formation and cleavage upon electron transfer. The research started from examining the interconversion hexaphenylethane derivatives 1 and dicationic bis (triarylmethane) dyes 2. It has been found that they constitute the dynamic and reversible redox pair showing vivid change in color and drastic structural change upon electron transfer. They surely are the promising candidate for the present purpose. Unfortunately, however, attempts to obtain the CT crystal of 1 with a variety of electron donors have been unsuccessful, preventing me from realizing my initial proposal. Next, the biphenyl-type electron acceptors having dicyanovinyl moieties were investigated. 2,2'-Disubstituted derivative was found to undergo C-C bond formation upon two-electron reduction. By combining the further isomerization of the reduction product, the latter system constitute a prototype of the novel electrochromic system with "write protect" option.