Resolving Photo-Induced Twisted Intramolecular Charge Transfer with Vibrational Anisotropy and TDDFT
Zhang, Wenkai1; Lan, Zhenggang2; Sun, Zheng1; Gaffney, Kelly J.1
刊名JOURNAL OF PHYSICAL CHEMISTRY B
2012-09-20
卷号116期号:37页码:11527-11536
中文摘要

The interplay between reaction environment and photochemical outcome has wide ranging implications for designing and directing light driven chemical conversions. We present a detailed mechanistic description of photoisomerization in julolidine malononitrile (JDMN) as the first step to characterizing this interplay between reaction pathways and reaction environment. We have used polarization resolved UV pump-mid-IR probe spectroscopy and time dependent DFT calculations to investigate the dynamics of charge transfer induced intramolecular rotation in JDMN. We have probed the mechanism and dynamics of photoisomerization with the symmetric and antisymmetric CN-stretch of the malononitrile group. These measurements show the S1 electronic excited state relaxes with a 12.3 ps time constant by isomerizing around both the C-C single and C-C double bond of the malononitrile group with a branching ratio of 1:5. Isomerization around the single bond leads to the formation of a metastable twisted excited state, while isomerization around the double bond leads to excited state quenching via a conical intersection between the S1 and S0 electronic states. We have characterized the electronic and nuclear structure of the long-lived excited state with pump-probe anisotropy measurements and time dependent DFT calculations using the CAM-B3LYP functional and the 6-31G(d,p) basis set. These calculations further confirm that isomerization around the malononitrile single bond forms a twisted intermolecular charge transfer excited state.

英文摘要The interplay between reaction environment and photochemical outcome has wide ranging implications for designing and directing light driven chemical conversions. We present a detailed mechanistic description of photoisomerization in julolidine malononitrile (JDMN) as the first step to characterizing this interplay between reaction pathways and reaction environment. We have used polarization resolved UV pump-mid-IR probe spectroscopy and time dependent DFT calculations to investigate the dynamics of charge transfer induced intramolecular rotation in JDMN. We have probed the mechanism and dynamics of photoisomerization with the symmetric and antisymmetric CN-stretch of the malononitrile group. These measurements show the SI electronic excited state relaxes with a 12.3 Ps time constant by isomerizing around both the C C single and C C double bond of the malononitrile group with a branching ratio of 1:5. Isomerization around the single bond leads to the formation of a metastable twisted excited state, while isomerization around the double bond leads to excited state quenching via a conical intersection between the Si and SO electronic states. We have characterized the electronic and nuclear structure of the long-lived excited state with pump probe anisotropy measurements and time dependent DFT calculations using the CAM-B3LYP functional and the 6-31G(d,p) basis set. These calculations further confirm that isomerization around the malononitrile single bond forms a twisted intermolecular charge transfer excited state.
学科主题仿真与模拟
WOS标题词Science & Technology ; Physical Sciences
类目[WOS]Chemistry, Physical
研究领域[WOS]Chemistry
关键词[WOS]MAGNETIC-RESONANCE RELAXATION ; FLUORESCENT MOLECULAR ROTORS ; TEMPERATURE IONIC LIQUIDS ; PHOTOISOMERIZATION DYNAMICS ; STILBENE ISOMERIZATION ; DECAY DYNAMICS ; FREE-VOLUME ; SPECTROSCOPY ; DEPENDENCE ; STATE
收录类别SCI
语种英语
WOS记录号WOS:000308855800015
公开日期2012-11-12
内容类型期刊论文
源URL[http://ir.qibebt.ac.cn:8080/handle/337004/1310]  
专题青岛生物能源与过程研究所_仿真模拟团队
作者单位1.Stanford Univ, PULSE Inst, SLAC Natl Accelerator Lab, Menlo Pk, CA 94025 USA
2.Chinese Acad Sci, Qingdao Inst Bioenergy & Bioproc Technol, Qingdao 266101, Shandong, Peoples R China
推荐引用方式
GB/T 7714
Zhang, Wenkai,Lan, Zhenggang,Sun, Zheng,et al. Resolving Photo-Induced Twisted Intramolecular Charge Transfer with Vibrational Anisotropy and TDDFT[J]. JOURNAL OF PHYSICAL CHEMISTRY B,2012,116(37):11527-11536.
APA Zhang, Wenkai,Lan, Zhenggang,Sun, Zheng,&Gaffney, Kelly J..(2012).Resolving Photo-Induced Twisted Intramolecular Charge Transfer with Vibrational Anisotropy and TDDFT.JOURNAL OF PHYSICAL CHEMISTRY B,116(37),11527-11536.
MLA Zhang, Wenkai,et al."Resolving Photo-Induced Twisted Intramolecular Charge Transfer with Vibrational Anisotropy and TDDFT".JOURNAL OF PHYSICAL CHEMISTRY B 116.37(2012):11527-11536.
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