Femtosecond broadband time-resolved fluorescence and transient absorption study of the intramolecular charge transfer state of methyl 4- dimethylaminobenzoate

Chris Tsz Leung Chan, Chopen Chan Wut Cheng, Keith Yat Fung Ho, Wai Ming Kwok

Research output: Journal article publicationJournal articleAcademic researchpeer-review

14 Citations (Scopus)

Abstract

A combined application of femtosecond broadband time-resolved fluorescence (fs-TRF), fluorescence anisotropy (fs-TRFA) and fs to microsecond (μs) transient absorption (TA) have been used to probe directly the dynamics, nature, formation and decay paths of the singlet intramolecular charge transfer (1ICT) state of methyl 4-dimethylaminobenzoate (1a) in acetonitrile. The result reveals explicit evidence for a common electronic origin (the Lanature) of the1ICT state and its precursor the locally excited (1LE) state to account jointly for the dual florescence known to this system. It also shows that the ICT reaction from the1LE to1ICT state occurs with time constant of ∼0.8 ps and the1ICT state formed decays with a ∼1.9 ns time constant leading mainly to a ππ* natured triplet state (3T1). The3T1then relaxes with a ∼4 μs lifetime under deoxygenated condition resulting in full recovery of the ground state (S0). As a case study, this work contributes novel experimental data for improved understanding of the mechanism of ICT reaction; it also reveals a distinct deactivation pattern for this prototype para-amino substituted aromatic carbonyl compound in acetonitrile.
Original languageEnglish
Pages (from-to)16306-16313
Number of pages8
JournalPhysical Chemistry Chemical Physics
Volume13
Issue number36
DOIs
Publication statusPublished - 28 Sep 2011

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

Cite this