S1/S0 Potential Energy Surfaces Experience Different Types of Restricted Rotation

Restricted Z/ e Photoisomerization and E/ Z Thermoisomerization by an Out-of-Plane Benzyl Group or In-Plane m-Pyridinium Group?

Jun Jia Xu, Robert Sung, Kuang-Sen Sung

Research output: Contribution to journalArticle

Abstract

Any method that can enhance the fluorescence of fluorophores is highly desirable. Fluorescence enhancement accomplished by restricted Z/E photoisomerization through intramolecular steric hindrance or relatively high bond order of a C?C double bond in a S1 excited state has rarely been studied. In this article, we used green fluorescent protein (GFP) chromophore analogues as a model to get new physical insights into the restricted Z/E photoisomerization and E/Z thermoisomerization phenomena. We found that the S1 and S0 potential energy surfaces (PESs) of the GFP chromophore analogues experience two dramatically different types of restricted rotation, and 2b can be a representative example. In its S1 PES, it is not the intramolecular steric hindrance between the out-of-plane benzyl group and the in-plane m-pyridinium group but the relatively high bond order of the I-bond in the S1 excited state of 2b that makes it have a higher barrier for the Z/E photoisomerization, a smaller Z/E photoisomerization quantum yield, and a higher fluorescence quantum yield. In its S0 PES, it is not the reduced bond order of the I-bond in the S0 ground state of 2b but the intramolecular steric hindrance between the out-of-plane benzyl group and the in-plane m-pyridinium group that makes it have an extra higher barrier for E/Z thermoisomerization and a much smaller E/Z thermoisomerization rate constant.

Original languageEnglish
Pages (from-to)4708-4716
Number of pages9
JournalJournal of Physical Chemistry A
Volume123
Issue number22
DOIs
Publication statusPublished - 2019 Jun 6

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Photoisomerization
Potential energy surfaces
potential energy
Fluorescence
Quantum yield
Chromophores
Green Fluorescent Proteins
Excited states
fluorescence
chromophores
analogs
proteins
Fluorophores
Ground state
excitation
Rate constants
ground state
augmentation

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry

Cite this

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title = "S1/S0 Potential Energy Surfaces Experience Different Types of Restricted Rotation: Restricted Z/ e Photoisomerization and E/ Z Thermoisomerization by an Out-of-Plane Benzyl Group or In-Plane m-Pyridinium Group?",
abstract = "Any method that can enhance the fluorescence of fluorophores is highly desirable. Fluorescence enhancement accomplished by restricted Z/E photoisomerization through intramolecular steric hindrance or relatively high bond order of a C?C double bond in a S1 excited state has rarely been studied. In this article, we used green fluorescent protein (GFP) chromophore analogues as a model to get new physical insights into the restricted Z/E photoisomerization and E/Z thermoisomerization phenomena. We found that the S1 and S0 potential energy surfaces (PESs) of the GFP chromophore analogues experience two dramatically different types of restricted rotation, and 2b can be a representative example. In its S1 PES, it is not the intramolecular steric hindrance between the out-of-plane benzyl group and the in-plane m-pyridinium group but the relatively high bond order of the I-bond in the S1 excited state of 2b that makes it have a higher barrier for the Z/E photoisomerization, a smaller Z/E photoisomerization quantum yield, and a higher fluorescence quantum yield. In its S0 PES, it is not the reduced bond order of the I-bond in the S0 ground state of 2b but the intramolecular steric hindrance between the out-of-plane benzyl group and the in-plane m-pyridinium group that makes it have an extra higher barrier for E/Z thermoisomerization and a much smaller E/Z thermoisomerization rate constant.",
author = "Xu, {Jun Jia} and Robert Sung and Kuang-Sen Sung",
year = "2019",
month = "6",
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doi = "10.1021/acs.jpca.9b02924",
language = "English",
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T2 - Restricted Z/ e Photoisomerization and E/ Z Thermoisomerization by an Out-of-Plane Benzyl Group or In-Plane m-Pyridinium Group?

AU - Xu, Jun Jia

AU - Sung, Robert

AU - Sung, Kuang-Sen

PY - 2019/6/6

Y1 - 2019/6/6

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