Investigation of Electronic-State Dependence of Photoreaction

分子的光反应在很大程度上取决于激发态的性质。研究激发态波函数特性与光反应之间的关系是很有意义的，因为这种研究阐明了电子的微观运动对光反应的影响。本项目的目的是主要通过发射光谱来研究光反应的电子态依赖性。为了进行这项研究，我们制作了发射分光光度计。我们购买了检测端的光谱仪、探测器和控制器。此前，我们已经购买了激发侧和灯具的光谱仪。新的分光光度计的灵敏度比旧的高得多，大大提高了研究效率。我们观察到了水杨醛相关分子的第一和第二激发单重态的荧光，并讨论了质子转移反应的电子态依赖性。通过理论研究，我们发现了波函数的节点对有机分子光反应的影响。此外，我们还研究了水杨醛三重态和离子态的质子转移反应，2-(2‘-羟基苯基)苯并噻唑、2-(2’-羟基苯基)苯并恶唑和2，2‘-联吡啶-3，3’-二醇三重态的质子转移，类胡萝卜素具有双重发光特性的溶剂效应，以及吡啶类化合物磷光较弱的原因。S.Nagaoka被选为日本化学会“Kagaku No Frontier VII”和“第六届青年学者讲座”。他还在美国化学学会出版的《物理化学杂志》(第95卷，10229-10235页，1991年)上发表了一篇特邀论文。

The photoreaction of molecules depends largely on the nature of the excited state. It is interesting to study the relationship between the characteristics of the wave function of the excited state and the photoreaction, because such a study clarifies the effect of microscopic motion of electrons on the resultant photoreaction. The purpose of this project is to study the electronic-state dependence of photoreactions mainly by means of the emission spectroscopy. In order to perform this study, we made an emission spectrophotometer. We bought the spectrometer of the detection-side, the detector, and the controller. Previously, we had already bought the spectrometer of the excitation-side and the lamp. The sensitivity of the new spectrophotometer is much larger than the old one and the efficiency of the study was enhanced very much. We observed the fluorescence from the first and second excited singlet states of the related molecules of salicylaldehyde and discussed the electronic-state dependence of the proton transfer reaction. From theoretical studies, we found the effect of the node of the wave function on the photoreaction of organic molecules. Furthermore, we studied the proton transfer reactions in the triplet state and the ionic state of the related molecules of salicylaldehyde, the proton transfer in the lowest triplet states of 2-(2'-hydroxyphenyl)benzothiazole, 2-(2'-hydroxyphenyl)benzoxazole, and 2,2'-bipyridyl-3,3'-diol, the solvent effect on the relaxation processes of carotenoids showing dual emissive characteristics, the reason for the weak phosphorescence of pyridines. S. Nagaoka was chosen as 'Kagaku No Frontier VII' and 'the 6th Young Scholar Lecture' of the Chemical Society of Japan. He also wrote an invited paper in The Journal of Physical Chemistry published from the American Chemical Society (Vol. 95, pp. 10229-10235, 1991).