Systematic investigations on fused π-system compounds of seven benzene rings prepared by photocyclization of diphenanthrylethenes
Systematic investigations on fused π-system compounds of seven benzene rings prepared by photocyclization of diphenanthrylethenes
复制标题
DOI：
10.1039/c7pp00040e
复制
发表时间：
2017-06-01
影响因子：
3.1
通讯作者：
Tani, Fumito
中科院分区：
文献类型：
--
作者：
Fujino, Shota;Yamaji, Minoru;Tani, Fumito
我们研究了 1-(n-菲基)-2-(m-菲基) 乙烯 (nEm; n, m = 1、3 和 9) 的光产物，以了解基于 NMR 光谱的光环化模式。通过X射线晶体学分析光产物的晶体结构，并基于发射和瞬态吸收测量研究光环化分子的光物理特征。通过二苯乙烯衍生物的光环化制备了1位和3位取代的菲衍生物用于合成nEm。我们从相应的 nEm 中获得了四种类型的初级光产物 (n@ m)。通过X射线晶体学测定，发现其中两种在单晶中具有外消旋分子结构。除了初级光产物外，还分离出两种类型的次级光产物（n@mPP）。所得光产物的荧光量子产率和寿命在溶液中测定，而确定的荧光量子产率在粉末中获得。通过激光光解技术对溶液中三重态-三重态吸收光谱的观察表明，系统间窜越到三重态与荧光过程竞争。
We studied the photoproducts of 1-(n-phenanthryl)-2-(m-phenanthryl) ethenes (nEm; n, m = 1, 3 and 9) for understanding photocyclization patterns based on NMR spectroscopy. The crystal structures of the photoproducts were analyzed by X-ray crystallography, and the photophysical features of the photocyclized molecules were investigated based on emission and transient absorption measurements. Phenanthrene derivatives substituted at the 1-and 3-positions were prepared for synthesizing nEm by photocyclization of stilbene derivatives. We obtained four types of primary photoproducts (n@ m) from the corresponding nEm. Two of them were found to have racemic molecular structures in the single crystal determined by X-ray crystallography. Besides the primary photoproducts, two types of secondary photoproducts (n@mPP) were isolated. Fluorescence quantum yields and lifetimes of the obtained photoproducts were determined in solution whereas the definite fluorescence quantum yields were obtained in the powder. Observation of the triplet-triplet absorption spectra in solution by laser photolysis techniques showed that intersystem crossing to the triplet state competes with the fluorescence process.