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THE EXCITONIC STRUCTURE AND EXCITED STATES DYNAMICS OF AZULENES

甘菊环的激子结构和激发态动力学

基本信息

批准号：
10640499
负责人：
SUZUKA Isamu
金额：
$ 0.32万
依托单位：
COLLEGE OF ENGINEERING, NIHON UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

项目摘要

It is expected that azulene forms the excimer easily because of the large dipole moment. However, the excimer and the dimer have never been reported. Azulenes are also well known to emit anomalous S_2 fluorescence contrary to Kasha's rule. We synthesized azulene cyano-derivatives that have larger dipole moment. The fluorescence spectra in solution, crystal and supersonic jet were observed in order to compare with the fluorescence and the relaxation dynamics of azulene.S_1 fluorescence was first observed in 1-cyanoazulene solution, while the quantum yield of S_2 fluorescence decreased to one tenth of azulene. We discussed these results in relation to the energy gap law.In crystal, the excimer fluorescence of azulene, 1-cyanoazulene and 2-cyanoazulene were observed in 420nm region. However, we could not detect the excimer fluorescence in solutions and a supersonic jet. It was suggested that the excimer formation is very difficult except in crystal. These results are characteristic in azulenes in contrast to other aromatic compound.Hole burning spectra of cyanoazulenes were measured in order to elucidate the dynamics from S_1. The S_1 life time was 1.8ps and 1.0ps in 1-cyanoazulene and 2-cyanoazulene, respectively. The later internal conversion in 1-cyanoazulene was related with the finding of S_1 emission.The photophysical properties of methyl- and phenyl-azulene are also investigating to elucidate the effect of electron donating group.

由于偶极矩较大，预计天青烯很容易形成准分子。然而，准分子和二聚体从未被报道过。众所周知，天青烯还会发出与卡沙定律相反的反常S_2荧光。我们合成了偶极矩较大的偶氮烯氰基衍生物。观察了溶液、晶体和超音速射流中的荧光光谱，并与偶氮烯的荧光和弛豫动力学进行了比较。在1-氰基偶氮烯溶液中首次观察到S_1荧光，而S_2荧光的量子产率下降到偶氮烯的十分之一。我们讨论了这些结果与能隙定律的关系。在晶体中，在420 nm处观察到了偶氮烯、1-氰基偶氮烯和2-氰基偶氮烯的准分子荧光。然而，我们在溶液和超音速射流中检测不到准分子荧光。结果表明，除了晶体外，准分子的形成是非常困难的。测量了氰基偶氮烯的烧孔光谱，以解释S_1的反应动力学。S_1在1-氰基偶氮烯和2-氰基偶氮烯中的寿命分别为1.8ps和1.0ps。1-氰基偶氮烯的后期内转化与S_1发射的发现有关。甲基和苯基偶氮烯的光物理性质也被研究，以阐明给电子基的影响。