引用本文:
【打印本页】   【HTML】   【下载PDF全文】   查看/发表评论  【EndNote】   【RefMan】   【BibTex】
←前一篇|后一篇→ 过刊浏览    高级检索
本文已被:浏览 681次   下载 921 本文二维码信息
码上扫一扫!
分享到: 微信 更多
光诱导噻吨酮与二苯胺间电子转移反应的溶剂化效应
陈琳,周巧慧,刘香,周晓国*,刘世林
作者单位E-mail
陈琳 中国科学技术大学合肥微尺度物质科学国家实验室化学物理系合肥230026  
周巧慧 中国科学技术大学合肥微尺度物质科学国家实验室化学物理系合肥230026  
刘香 中国科学技术大学合肥微尺度物质科学国家实验室化学物理系合肥230026  
周晓国* 中国科学技术大学合肥微尺度物质科学国家实验室化学物理系合肥230026 xzhou@ustc.edu.cn 
刘世林 中国科学技术大学合肥微尺度物质科学国家实验室化学物理系合肥230026  
摘要:
利用纳秒激光闪光光解技术研究了噻吨酮(TX)和二苯胺(DPA)的光化学反应.在355 nm光激发下,TX的基电子态跃迁至第一激发态进而通过系间窜越生成三重态3TX*. 在乙腈/水混合溶剂中,3TX*与DPA反应体系的瞬态吸收光谱呈现出四个谱峰,分别对应3TX*、TXH·、TX·-和DPA·+的吸收. 随着溶剂极性的增大,这些吸收峰均发生红移. 结合动力学测量,3TX*与DPA的反应机理被证实为电子转移伴随质子转移过程. 3TX*与DPA反应的猝灭速率常数随溶剂极性的增大而缓慢减小,9.7×109 L/(mol·s)(纯乙腈)、8.7×109 L/(mol·s)(乙腈:水=9:1)、8.0×109 L/(mol·s)(乙腈:水=4:1)和7.5×109 L/(mol·s)(乙腈:水=1:1). 质子溶剂-水在此反应中的作用不明显,溶剂的极性对3TX*与DPA电子转移速率的影响不大,表明3TX*3*3ππ*三重态吸引DPA中电子的能力相仿.
关键词:  电子转移,质子化,反应机理,吸收光谱,激光闪光光解
DOI:10.1063/1674-0068/28/cjcp1503054
分类号:
基金项目:
Solvent Effect on the Photoinduced Electron Transfer Reaction Between Thioxanthen-9-one and Diphenylamine
Lin Chen,Qiao-hui Zhou,Xiang Liu,Xiao-guo Zhou*,Shi-lin Liu
Abstract:
Photoinduced chemical reaction between thioxanthen-9-one (TX) and diphenylamine (DPA) were investigated by the nanosecond laser flash photolysis. With photolysis at 355 nm, the triplet TX (3TX*) is produced via a Franck-Condon excitation and intersystem crossing. In the transient absorption spectra of the reduction of 3TX* by DPA in pure and aqueous CH3CN, four bands are clearly observed and assigned to absorption of 3TX*, TXH·, TX·- and DPA·+, respectively. With the increase of solvent polarity, the blue-shift was observed for all absorption bands of the intermediates. With the aid of dynamic decay curves, an electron transfer followed by a protonation process is confirmed for the reduction of 3TX* by DPA. The quenching rate constants of 3TX* by DPA very slightly decrease from 9.7×109 L/(mol·s) in pure CH3CN, to 8.7×109 L/(mol·s) in CH3CN:H2O (9:1), 8.0×109 L/(mol·s) in CH3CN:H2O (4:1) and 7.5×109 L/(mol·s) in CH3CN:H2O (1:1). Therefore water plays a minor role in the title reaction, and moreover no obvious medium effect of solvent polarity is observed for the electron transfer between 3TX* and DPA, indicating that the 3* and 3ππ* states of TX have the approximate ability to attract an electron from DPA.
Key words:  Electron transfer, Protonation, Reaction mechanism, Absorption spectra, Laser flash photolysis