Time-resolved resonance Raman study of the triplet state of the p-hydroxyphenacyl acetate model phototrigger compound

Chensheng Ma, Wing Sum Chan, Wai Ming Kwok, Peng Zuo, David Lee Phillips

Research output: Journal article publicationJournal articleAcademic researchpeer-review

26 Citations (Scopus)

Abstract

Picosecond and nanosecond time-resolved resonance Raman spectroscopy have been used to study the dynamics and structure of the phototrigger compound p-hydroxyphenacyl acetate (HPA) in acetonitrile solution. An intermediate was observed that exhibited significant quenching by oxygen. This intermediate was identified and attributed to the ππ* triplet state of HPA. Temporal evolution at early picosecond times indicates rapid intersystem crossing conversion and subsequent relaxation of the excess energy of the initially formed triplet state. B3LYP/6-311G** density functional theory (DFT) calculations were done to determine the structures and vibrational frequencies for both the HPA triplet and ground states. The experimental and theoretical results were compared and discussed in relation to the initial pathway for the p-hydroxyphenacyl deprotection reaction and the nature of the triplet state relative to other aromatic carbonyl compounds. The present results demonstrate the utility of applying ultrafast vibrational spectroscopy to study the mechanism of the photorelease process in phototrigger compounds.
Original languageEnglish
Pages (from-to)9264-9276
Number of pages13
JournalJournal of Physical Chemistry B
Volume108
Issue number26
DOIs
Publication statusPublished - 1 Jul 2004
Externally publishedYes

ASJC Scopus subject areas

  • Surfaces, Coatings and Films
  • Physical and Theoretical Chemistry
  • Materials Chemistry

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