Determination of Astaxanthin and Canthaxanthin Triplet Properties in Different Polarities of the Solvent by Laser Flash Photolysis  

作　　者：李海霞 张鹏 宋西玉 王文锋 

机构地区：[1]Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China [2]Graduate University of Chinese Academy of Sciences, Beijing 100049, China

出　　处：《Chinese Journal of Chemistry》2011年第7期1535-1540,共6页中国化学（英文版）

基　　金：Project supported by the National Natural Science Foundation of China （No. 10675158）.

摘　　要：Triplet-triplet extinction coefficients for astaxanthin （I） and canthaxanthin （II） in different deaerated polarity solutions of MeCN and benzene were evaluated by laser flash photolysis at 298 K in the spectral region from 350 to 650 nm by energy transfer method, employing 2-acetonaphthone as sensitizer. The triplet-triplet extinction coeffi- cients in MeCN and benzene were different in terms of the carotenoid present. The maximum triplet-triplet extinc- tion coefficient was 0.1-1.7 ×10^5 L·mol^-1·cm^-1 in different solvents. The rate constants of triplet decay were I： 1.25×10^10 L·mol^-1·s^-1, II： 1.12×10^10 L·mol^-1·s^-1 in MeCN; and I： 1.75×10^10 L·mol^-1, II： 3.27×10^10 L·mol^-1·s^-1 in benzene. The bimolecular rate constants of energy transfer from triplet excited 2-acetonaphthone to carotenoids were determined from the linear regression of the decay rate constant of 2-acetonaphthone triplet at varying carotenoid concentrations. The triplet lifetimes of ^3AST^＊ and 3CAN^＊ in different solvents were also determined. The results indicated that triplet energy transfer was nearly diffusion-controlled.Triplet-triplet extinction coefficients for astaxanthin （I） and canthaxanthin （II） in different deaerated polarity solutions of MeCN and benzene were evaluated by laser flash photolysis at 298 K in the spectral region from 350 to 650 nm by energy transfer method, employing 2-acetonaphthone as sensitizer. The triplet-triplet extinction coeffi- cients in MeCN and benzene were different in terms of the carotenoid present. The maximum triplet-triplet extinc- tion coefficient was 0.1-1.7 ×10^5 L·mol^-1·cm^-1 in different solvents. The rate constants of triplet decay were I： 1.25×10^10 L·mol^-1·s^-1, II： 1.12×10^10 L·mol^-1·s^-1 in MeCN; and I： 1.75×10^10 L·mol^-1, II： 3.27×10^10 L·mol^-1·s^-1 in benzene. The bimolecular rate constants of energy transfer from triplet excited 2-acetonaphthone to carotenoids were determined from the linear regression of the decay rate constant of 2-acetonaphthone triplet at varying carotenoid concentrations. The triplet lifetimes of ^3AST^＊ and 3CAN^＊ in different solvents were also determined. The results indicated that triplet energy transfer was nearly diffusion-controlled.

关 键 词：ASTAXANTHIN CANTHAXANTHIN energy transfer laser flash photolysis PHOTOCHEMISTRY 

分 类 号：TQ630.44[化学工程—精细化工] X52[环境科学与工程—环境工程]