溶剂对四苯基卟啉氯化锰飞秒瞬态吸收光谱的影响  

Sovlent Influence on the Femtosecond Transient Absorption Spectra of Tetraphenylporphyrin Manganese(Ⅲ)Chloride

作　　者：李万红 于明月 王丽丽[2] 朱德煌 彭素红 王惠[2] 刘海洋[4] Li Wanhong;Yu Mingyue;Wang Lili;Zhu Dehuang;Peng Suhong;Wang Hui;Liu Haiyang(College of Chemsitry and Bioengineering,Yichun University,Yichun 336000,China;State Key Laboratory of Optoelectronics Materials and Technologies,Sun Yat-sen University,Guangzhou 510275,China;Key Laboratory of Green Chemical Technology of Fujian Province University,College of Ecology and Resources Engieneering,Wuyi University,Nanping 354300,China;Department of Chemistry,South China University of Technology,Guangzhou 510641,China)

机构地区：[1]宜春学院化学与生物工程学院,宜春336000 [2]中山大学光电材料与技术国家重点实验室,广州510275 [3]武夷学院生态与资源工程学院绿色与化工技术福建省高等学校重点实验室,南平354300 [4]华南理工大学化学系,广州510641

出　　处：《化学学报》2023年第4期345-350,共6页Acta Chimica Sinica

基　　金：国家自然科学基金(No.21671068);宜春学院2018地方发展研究中心项目(No.DF2018021);江西省教育厅科学技术项目(Nos.GJJ2201723,GJJ2201724);江西省卫生健康委科技计划项目(No.202212701);绿色化工技术福建省高校重点实验室开放基金(WYKF-GCT2022-1)资助。

摘　　要：采用稳态和飞秒瞬态吸收光谱技术研究了四苯基卟啉氯化锰Mn^(Ⅲ)(TPP)Cl在甲苯(TOL)、二氯甲烷(DCM)、乙腈(ACN)和N,N-二甲基甲酰胺(DMF)四种溶剂中的光物理性质.结果表明随溶剂极性的增加,其紫外-可见吸收光谱的B带与Q带与飞秒瞬态对应的漂白信号均发生蓝移.随着Mn^(Ⅲ)(TPP)Cl二氯甲烷溶液浓度的增加,^(5)S_(2)态寿命无明显变化,^(5)S_(1)态和^(5)T_(1)态寿命依次变短.在四种溶剂中,非极性溶剂甲苯中的^(5)S_(2)态寿命最长而5S1和5T1态寿命最短,这与^(5)S_(2)→^(5)S_(1)能差最大,^(5)S_(1)→^(5)S_(0)能差最小对应.从弱极性DCM到极性更大的DMF时,^(5)S_(1)和^(5)T_(1)态寿命依次缩短.从非极性TOL到极性ACN时^(5)S_(2)态寿命依次缩短.在极性溶剂DMF中,锰卟啉的^(5)S_(2)态寿命更长.这主要是配位溶剂DMF中的氮原子与锰卟啉^(5)S_(2)激发态进行配位,从而使五配位的锰卟啉变成六配位的锰卟啉,结果使锰卟啉的激发态寿命延长.锰卟啉在DMF中具有更长的^(5)S_(2)态寿命是溶剂的配位作用与极性作用共同影响的结果且配位作用为主.The photophysical properties of tetraphenylporphyrin manganese(Ⅲ)chloride Mn^(Ⅲ)(TPP)Cl in four solvents of toluene(TOL),dichloromethane(DCM),acetonitrile(ACN)and N,N-dimethylformamide(DMF)were investigated through the steady-state and the femtosecond transient absorption spectroscopy.The Mn^(Ⅲ)(TPP)Cl molecule is populated to the lifetimes of the second excited singlet state(^(5)S_(2))with pump pulse at 400 nm.Broad band white light continuum in the visible region from 420 nm to 700 nm is used in the probe.With a detail analysis of the measured transient spectra,three decay time constants τ_(1),τ_(2) and τ_(3) corresponding to the lifetime of the second excited singlet state(^(5)S_(2)),the lifetime of the first excited singlet state(^(5)S_(1))and the first excited triplet state(^(5)T_(1))are obtained in the four solvents.The results show that the steady-state B-band and Q-band absorption and the bleaching signal of the femtosecond transient absorption exhibit blue-shift.With the increase of the concentration of Mn^(Ⅲ)(TPP)Cl in DCM,the lifetimes of the second excited singlet state(^(5)S_(2))had no significant change.And the lifetimes of the first excited singlet state(^(5)S_(1))and the first excited triplet state(^(5)T_(1))shortened.In these four solvents,its ^(5)S_(2) lifetime in nonpolar solvent TOL was the longest and the ^(5)S_(1) lifetime,^(5)T_(1) lifetime were the shortest.This is in accord with the largest ^(5)S_(2)→^(5)S_(1) energy gap and the least ^(5)S_(1)→5S0 energy gap in TOL.From weak polar solvent DCM to the more polar solvent DMF,the ^(5)S_(1) lifetime and ^(5)T_(1) lifetime shortened.With the solvent polarity increasing from nonpolar solvent TOL to the more polar solvent ACN,the ^(5)S_(2) lifetime shortened.While its ^(5)S_(2) lifetime becomes longer in polar solvent DMF.This is mainly caused by the axial ligation of nitrogen atom of coordinating solvent DMF with ^(5)S_(2) of Mn^(Ⅲ)(TPP)Cl.The structure of Mn^(Ⅲ)(TPP)Cl changed from five-coordinate to six-coordinate.As a resu

关 键 词：四苯基卟啉氯化锰 卟啉 锰 瞬态吸收光谱 

分 类 号：O641.4[理学—物理化学]