Document Detail


Site-selective photoinduced electron transfer from alcoholic solvents to the chromophore facilitated by hydrogen bonding: a new fluorescence quenching mechanism.
MedLine Citation:
PMID:  17616225     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Solute-solvent intermolecular photoinduced electron transfer (ET) reaction was proposed to account for the drastic fluorescence quenching behaviors of oxazine 750 (OX750) chromophore in protic alcoholic solvents. According to our theoretical calculations for the hydrogen-bonded OX750-(alcohol)(n) complexes using the time-dependent density functional theory (TDDFT) method, we demonstrated that the ET reaction takes place from the alcoholic solvents to the chromophore and the intermolecular ET passing through the site-specific intermolecular hydrogen bonds exhibits an unambiguous site selectivity. In our motivated experiments of femtosecond time-resolved stimulated emission pumping fluorescence depletion spectroscopy (FS TR SEP FD), it could be noted that the ultrafast ET reaction takes place as fast as 200 fs. This ultrafast intermolecular photoinduced ET is much faster than the diffusive solvation process, and even significantly faster than the intramolecular vibrational redistribution (IVR) process of the OX750 chromophore. Therefore, the ultrafast intermolecular ET should be coupled with the hydrogen-bonding dynamics occurring in the sub-picosecond time domain. We theoretically demonstrated for the first time that the selected hydrogen bonds are transiently strengthened in the excited states for facilitating the ultrafast solute-solvent intermolecular ET reaction.
Authors:
Guang-Jiu Zhao; Jian-Yong Liu; Li-Chuan Zhou; Ke-Li Han
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2007-07-07
Journal Detail:
Title:  The journal of physical chemistry. B     Volume:  111     ISSN:  1520-6106     ISO Abbreviation:  J Phys Chem B     Publication Date:  2007 Aug 
Date Detail:
Created Date:  2007-07-26     Completed Date:  2007-09-14     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  101157530     Medline TA:  J Phys Chem B     Country:  United States    
Other Details:
Languages:  eng     Pagination:  8940-5     Citation Subset:  IM    
Affiliation:
State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, China.
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MeSH Terms
Descriptor/Qualifier:
Alcohols / chemistry*
Electrons
Fluorescence
Hydrogen Bonding
Molecular Structure
Oxazines / chemistry*
Photochemistry
Solvents / chemistry
Spectrometry, Fluorescence / methods
Chemical
Reg. No./Substance:
0/Alcohols; 0/Oxazines; 0/Solvents; 67556-77-8/oxazine 750

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