Department of Chemistry & Biochemistry, Miami University, Oxford, Ohio 45056, United States.
J Org Chem. 2011 Nov 4;76(21):9188-91. doi: 10.1021/jo201842q. Epub 2011 Oct 12.
The excited-state properties of unsubstituted ortho-phenylene oligomers have been studied using TD-DFT. Calculations of vertical transitions at the helical ground-state geometries are in good qualitative agreement with the experimental UV-vis spectra. In the excited state, the spring-like compounds compress; for the longer oligomers, this compression is localized at one end of the oligomer. This behavior explains the unusual experimentally observed hypsochromic shifts in fluorescence spectra with increasing oligomer length.
使用 TD-DFT 研究了未取代的邻苯二酚低聚物的激发态性质。在螺旋基态几何形状下的垂直跃迁计算与实验的 UV-vis 光谱具有良好的定性一致性。在激发态下，弹簧状化合物会被压缩；对于较长的低聚物，这种压缩会集中在低聚物的一端。这种行为解释了实验中观察到的随着低聚物长度增加而出现的荧光光谱的蓝移现象。
