Control and functionalizations of dynamics of radicals and ionic intermediates generated by photocatalysts

本论文针对有机光化学中自由基和离子中间体的独特性质，从以下三个方面研究了新型功能的光化学和电子转移反应的设计和开发：（1）利用电子转移诱导的成键/断裂反应掺杂和储存空穴和电子。设计了一种牺牲给体-光敏剂分子和长链四氰基醌二甲烷的交替层状LB膜，在辐照下观察到有机薄膜导电性的产生。此外，电子受体与一个稳定的自由基，通过单电子还原形成共价键的制备，这可能使可逆的光化学掺杂反应。(2)利用取代降冰片二烯的光化学环化和四环烷的电子转移价异构化构建新型可逆体系。(a)光致变色系统设计用于记录重复计数与四环烷携带牺牲电子供体，进行键断裂后，通过单电子氧化的逆反应。(b)触发型光致变色系统，其通过每次脉冲光照射重复开和关循环，利用被羧酸取代的降冰片二烯-四环体系的酸度变化。(3)新型功能界面反应的发展：此外，通过三苯胺聚合物的氧化聚合形成电致变色和导电薄膜，光催化反应的静电控制，通过光解离反应产生高自旋态已经进行了研究。

Design and development of photochemical and electron-transfer reactions for novel functionalities have been studied, focusing on unique characteristics of radical and ionic intermediates in organic photochemistry, with three directions as follows: (1) Doping and storage of hole and electron utilizing electron-transfer induced bond formation/cleavage reactions. Generation of electric conductivity of organic thin films was observed upon the irradiation of alternatively layered LB films of a designed sacrificial donor-photo-sensitizer molecule and tetracyanoquinodimethane with long alkyl chain. In addition, electronic acceptors incorporated with a stable radical to form covalent bond by one-electron reduction were prepared which may enable a reversible photochemical doping reaction. (2) Construction of novel reversible systems employing photochemical cyclization of substituted norbornadienes and the electron-transfer valence isomerization of quadricyclanes. (a) Photochromic system designed for recording of repeat counts with quadricyclanes carrying sacrificial electron donors, which undergo bond-cleavage upon reverse reaction by the one-electron oxidation. (b) Flip-flop type photochromic system, which repeats on and off cycles by every pulsed light irradiation, utilizing the acidity change of a norbornadiene-quadricyclae system substituted with carboxylic acid. (3) The development of novel functional interfacial reactions: In addition, formation of electrochromic and conductive thin films by oxidative polymerization of triphenylamine olygomers, electrostatic control of photocatalytic reactions, generation of the high spin states by photodissociation reactions have been studied.