摘要
采用时间分辨红外吸收光谱方法，研宄了邻甲基苯甲酸安息香酯在266nm激光作用下发生的光化学反应，并考察了溶剂对反应过程的影响．从瞬态红外光谱上观察到了邻甲基苯甲酸和苯甲酰自由基及苯偶酰，提供了直接的光谱证据证明了脱保护反应及C-C=O处均裂反应的发生．通过对比溶剂中不同水含量下均裂反应中间体及邻甲基苯甲酸的产率，发现水含量在溶剂中的增加能促进脱保护反应的发生．
The benzoin group caged compound has received strong interests due to its excellent photo- deprotection properties and wide use in chemical and biological studies. We used timeresolved infrared spectroscopy to investigate the photochemical reaction of the benzoin caged compound, o-（2-methylbenzoyl）-DL-benzoin under 266 nm laser irradiation. Taking advantage of the specific vibrational marker bands and the IR discerning capability, we have detected and identified the uncaging product 2-methylbenzoic acid, and two intermediate radicals of benzoyl and 2-methylbenzoate benzyl in the transient infrared spectra. Our results provide spectral evidence to support the homolytic cleavage reaction of C-C=O bond in competition with the deprotection reaction. Moreover, the product yields of 2-methylbenzoic acid and benzoyl radical were observed to be affected by solvents and a largely water contalning solvent can be in favor of the deprotection reaction.
基金
This work was supported by the National Natural Science Foundation of China （No.21333012 and No.21425313） and the National Basic Research Program of China （No.2013CB834602）.
