Weihua Chen, Eric B. Twum, Lin-lin Li
Jan 6, 2012
Citations
0
Influential Citations
29
Citations
Journal
The Journal of organic chemistry
Abstract
2-(2'-Hydroxyphenyl)benzoxazole (HBO) derivatives represent an important class of luminescent materials, as they can undergo excited state intramolecular proton transfer (ESIPT). The material's ESIPT properties are dependent on the ratio of two different rotamers, whose interconversion is poorly understood. By using HBO derivative 4, the rotational energy barrier of 2- (2',6'-hydroxyphenyl)benzoxazole is determined to be 10.5 kcal/mol by variable-temperature NMR. Although a HBO derivative typically exhibits two rotamers with O···H-O (e.g., 1a) and N···H-O bonding (e.g., 1b), correlation of NMR with fluorescence data reveals that the rotamer with N···H-O bonding is predominant in the solution.