摘要
以四苯基卟啉为实验模板,结合稳态吸收光谱、荧光光谱、瞬态吸收光谱、动力学数据及理论计算结果研究了光激发4种金属配位卟啉的光谱性质.光激发后,四苯基卟啉化合物TPP-2H,TPP-Zn和TPP-Mg稳态吸收光谱Soret带谱峰强度均明显降低,TPP-Ni吸收强度由0.3 a.u.增至1.3 a.u.,TPP-FeCl谱峰变化较小.TPP-2H和镁、锌配位卟啉的瞬态吸收光谱Soret带出现明显负峰,激光激发后其瞬态中间体的消光系数(εt)小于基态的消光系数(εG),ΔOD值为负值;3种卟啉正负峰微秒级衰减动力学过程表明,光激发后分子产生较为稳定的中间态,有利于光电转换或光反应.实验和理论研究表明,金属卟啉光学性质差异由金属配位空轨道和电子排布引起.以上卟啉光学性质可协助理解光合作用过程,并为选择光电转换新型卟啉材料的配位金属提供实验支持.
The naturally selected chlorophyll and heme,and zinc or nickel coordinated porphyrin photosensi⁃tizer showed excellent photochemical and photophysical properties.Photoexcitation of metalloporphyrin to the excited state is the first step of reaction,which is the research priorities and challenges.The classical template molecules of porphyrins tetraphenylporphyrin(TPP-2H),and four metal-coordinated tetraphenylporphyrins,TPP-FeCl,TPP-Ni,TPP-Mg and TPP-Zn,were chosen for the investigations of their photochemical and photo⁃physical properties.The Soret band absorption peak intensities of photoexcited TPP-2H,TPP-Zn and TPP-Mg decreased significantly in steady state absorption spectrum,while the counterpart peak of TPP-Ni increased obviously from 0.3 a.u.to 1.3 a.u..However,the peak location and intensity of TPP-FeCl remained almost the same.According to the transient absorption spectrum,the Soret band negative peaks of TPP-2H,TPP-Mg and TPP-Zn had the negativeΔOD values for the lower molar absorption coefficientεt thanεG of ground state com⁃pounds.The positive and negative absorption peaks microsecond lifetime decay kinetics of TPP-2H,TPP-Mg and TPP-Zn confirmed the relatively stable transient excited states after the photoexcitation.All the experimen⁃tal and theoretical data manifested that the unoccupied orbitals and electron distribution of metal ion in the cen⁃ter of porphyrins would induce the diversification of porphyrin photochemical and photophysical properties.The experimental research further assists to comprehend photosynthesis process and provides an important ba⁃sis for the selection of coordination metal in the porphyrin application research field of photoelectric conversion.
作者
马子辉
王梦妍
曹洪玉
唐乾
王立皓
郑学仿
MA Zihui;WANG Mengyan;CAO Hongyu;TANG Qian;WANG Lihao;ZHENG Xuefang(College of Life Science and Biotechnology,Dalian University,Dalian 116622,China;College of Environmental and Chemical Engineering,Dalian University,Dalian 116622,China)
出处
《高等学校化学学报》
SCIE
EI
CAS
CSCD
北大核心
2021年第3期767-775,共9页
Chemical Journal of Chinese Universities
基金
国家自然科学基金(批准号:21601025,21571025,21601024,21506018)
大连市高层次创新人才项目(批准号:2017Q156)
大连大学博士启动项目(2019)资助.
关键词
金属卟啉
光激发
瞬态吸收光谱
衰减动力学
电子转移
Metalloporphyrin
Photoexcitation
Transient absorption spectrum
Decay kinetics
Electronic transfer
