Fundamental Research on Chemi-and Bioluminescence for High-Efficiency Light Emission

在化学发光和生物发光中，发光是由不稳定中间体热分解形成的羰基化合物的激发态发出的，例如前者是二氧乙烷，后者是二氧乙烷。羰基化合物的热分解产生激发态的机理尚不清楚，因为协调的方式导致三态，只产生弱发射。Schuster曾报道过包含分子内电子转移的CIEEL机制，但最近发现这个想法不能解释一些实验事实。本文研究了化学和生物发光化合物的氧化机理以及二氧乙烷的热分解机理。结果如下：对荧光素的主要成分咪唑吡嗪酮进行了氧合反应，并测定了二氧酮的结构。制备了各种洛芬衍生物（2,4,5-三苯基咪唑），发现了一个量子产率非常高（0.8）的结构条件，并提出了分子内电子转移的参与。具有富电子烯烃结构的化合物，例如生物异喹啉盐的还原种，被发现与分子氧和/或超氧化物反应。新制备的3-芳基二氧乙烷在室温下分解释放，芳基对二氧乙烷环的构象对二氧乙烷的释放强度和稳定性有很大影响。

In the chemiluminescence and bioluminescence, the light emission is brought out from an excited state of carbonyl compounds formed by thermal decomposition of unstable intermediates, such as dioxetanes in the former and dioxetanones in the latter, respectively. The mechanism of the thermal decomposition to give an excited state of carbonyl compounds is still unclear, because the concerted way leads to a triplet state which gives only weak emission. Schuster reported CIEEL mechanism which contains intramolecular electron transfer, but recently the idea was found not to explain some experimental facts.In this research the oxygenation mechanism of chemi-and bio-luminescent compounds and thermal decomposition mechanism of dioxetanes were investigated. The results obtained are as follows : The oxygenation of imidazopyrazinone which is a main part of luciferins was carried out, and the structure of the dioxetanone was determined. Various derivatives of lophine (2,4,5-triphenylimidazol) were prepared and a structural condition which has very high quantum yield (0.8) was found, and involvement of the intramolecular electron transfer was suggested. Compounds which have electron rich olefinic structure, for example the reduced species of biisoquinolinium salts were found to react with molecular oxygen and/or superoxide. For newly prepared 3-aryl dioxetanes which decompose at room temperature to give emission, the conformation of the aryl group to the dioxetane ring was shown to have strong effect on the emission intensity and on the stability of the dioxetanes.