摘要
利用时间分辨电子自旋共振(TR-ESR)方法,研究了稳定自由基TEMPO和生物抗氧化剂维生素C(VC)对萘醌(NQ)激发三重态~3NQ~*的猝灭机理和猝灭动力学。光解NQ/EG体系,~3NQ~*从EG上抽氢生成萘醌中性自由基NQH~*和乙二醇碳自由基CH_2CH(OH)_2。当体系中加入稳定自由基TEMPO时,TEMPO对~3NQ~*有明显的猝灭作用,猝灭速率常数为1.14×10~7 L·mol^(-1)·s^(-1)。对于NQ/VC/EG-H_2O溶液,~3NQ~*不仅可以从EG上夺氢,还从VC上夺氢,VC对~3NQ~*也有明显的猝灭作用,猝灭速率常数为1.11×10~7 L·mol^(-1)·s^(-1)。TEMPO和VC对~3NQ~*的猝灭反应都受扩散控制。
The reaction mechanism and dynamics of the laser induced excited triplet of 1,4-naphthoquinone （^3NQ＊） quenched by TEMPO and biological antioxidant vitamin C （VC） were investigated by means of time resolution electron spin resonance （TR-ESR） method. During the photolysis of NQ/EG （ethylene glycol） solution, ^3NQ＊ abstracts hydrogen atom from solvent molecule EG. and the neutral radical NQH＊ and EG ketyl radical CH2CH（OH）2 were generated. When TEMPO was added into NQ/EG solution, TEMPO is an effective quencher of 3NQ＊ and the quenching rate constant is 1.14×10^7L·mol^-1·S^-1. For NQ/VC/EG-H20 solution, 3NQ＊ abstracts hydrogen atom not only from solvent EG but also from VC. VC is also an effective quencher of 3NQ＊ and the quenching rate constant is 1.11×10^7L-mol^-1·S^-1. The quenching reactions of ^3NQ＊ by TEMPO and VC are both controlled by diffusion.
出处
《量子电子学报》
CAS
CSCD
北大核心
2011年第3期271-277,共7页
Chinese Journal of Quantum Electronics
基金
国家自然科学基金(20903004)
安徽高校省级自然科学研究重点项目(KJ2010A145)
关键词
光谱
萘醌
TEMPO
维生素C
时间分辨电子自旋共振
spectroscopy
1,4-naphthoquinone
TEMPO
vitamin C
time resolution electron spin resonance
