[3+3] -PHOTOCYCLOADDITION OF ARENEDICARBOXYLIC ACID DERIVATIVES AND ALKYLBENZENES

本研究的目的是阐明[3+3]-光环加成芳烃二羧酸衍生物和烷基苯的机理和适用性。得到的结果如下：1。通过对萘环1、2-、1、3-、1、4-、2、3-、1、2、3-、1、2、3-、1、8位上有酸酐、亚胺、二酯、二硝基基团的萘衍生物与甲苯、二甲苯等烷基苯的光反应的研究，发现萘环1、8位上有酸酐、亚胺基团的萘衍生物的反应中普遍存在[3+3]-光环加成。在具有非萘芳烃结构的芳烃二羧酸衍生物，如苯、蒽或菲的反应中，观察到没有[3+3]-光环加成。发现1,8-萘二甲酸酐和1,8-萘二甲酸亚胺在烷基苯作用下的荧光猝灭速率常数与[3+3]-光加成的发生有很好的相关性。从烷基苯到芳烃二羧酸衍生物单线态激发态的单电子转移相关的自由能变化AG是决定所观察到的光反应类型的重要因素。大的负AG值似乎是反应发生的必要条件。根据这些结果，提出了[3+3]-光环加成反应的可能机理，包括电子从烷基苯转移到芳烃二羧酸衍生物的单线态激发态、形成的自由基离子对内的质子转移、生成的自由基对内的电子转移以及最终阴离子和阳离子之间的热环加成反应。通过反应机理合理地解释了反应的适用性和溶剂对反应的影响。

The purpose of this investigation is to clarify the mechanism and applicability of [3+3]-photocycloaddition of arenedicarboxylic acid derivatives and alkylbenzenes. The results obtained are as follows :1. From the investigations of the photoreactions of naphthalene derivatives, having acid anhydride, imide, diester, and dicyano groups at the 1,2-, 1,3- 1,4-, 2,3-, or, 1, 8-positions of the naphthalene ring, with alkylbenzenes, such as toluene, xylenes, and so on, [3+3]-photocycloaddition was found to be general in the reactions of naphthalene derivatives, having acid anhydride and imide group at the 1,8-positions of the naphthalene ring.2. No [3+3]-photocycloadditions were observed in the reactions of arenedicarboxylic acid derivatives, having arene structure other that naphthalene, such as benzene, anthracene, or phenanthrene.3. The quenching rate constants of the fluorescence of 1 , 8-naphthalenedicarboxylic anhydride and 1,8-naphthalenedicarboximide by alkylbenzenes were found to correlate well to the occurrence of the [3+3]-photoaddition.4. The free energy change AG associated with one-electron transfer from alkylbenzenes to the singlet excited states of arenedicarboxylic acid derivatives were revealed to play an important role to determine the type of the observed photoreactions. A large negative AG value seems to be essential for the occurrence of the reaction.5. From these results, possible reaction mechanism for the [3+3]-photocycloaddition, involving electron transfer from alkylbenzenes to the singlet excited states of arenedicarboxylic acid derivatives, proton transfer within the formed radical ion pair, electron transfer within the producedradical pair, and final thermal cycloaddition between the resulted anion and cation, was proposed. Applicability of the reaction and solvent effect on the reaction were reasonably explained by the reaction mechanism.