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

在化学发光和生物发光中，光发射来自不稳定中间体的热分解所形成的羰基化合物的激发态，例如前者中的二氧杂环己烷和后者的二氧杂环己酮。由于协同作用导致的三重态只有微弱的发射，所以其热分解产生羰基化合物激发态的机理尚不清楚。Schuster报道了包含分子内电子转移的CIEEL机理，但最近发现这一观点不能解释一些实验事实。本研究对化学发光和生物发光化合物的氧化机理和二氧六环的热分解机理进行了研究。主要研究结果如下：对荧光素的主要成分--咪唑并吡嗪酮进行了氧化反应，确定了其结构。合成了洛芬(2，4，5-三苯基咪唑)的各种衍生物，发现了一个具有很高量子产率(0.8)的结构条件，并提出了分子内电子转移的参与。具有富含电子的烯烃结构的化合物，例如还原的联二异喹啉盐物种，被发现与分子氧和/或超氧化物反应。对于新合成的在室温下分解发射的3-芳基二氧杂环己烷，芳基与二氧杂环己烷的构象对发射强度和稳定性有很大的影响。

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.