Influence of substituent and solvent on the radiative process of singlet excited states of novel cyclic azacyanine derivatives

Digambara Patra, Nagham N. Malaeb, Makhluf J. Haddadin, Mark J. Kurth

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

The photophysical properties of novel cyclic azacyanine derivatives have been investigated in acetonitrile, N-butyronitrile, methanol, ethanol, DMF and water. Introduction of electron donating or accepting groups on the cyclic azacyanine has a direct impact on the spectroscopic and photophysical properties. Irrespective of the nature of the substitution, azacyanine shows a general solvent relaxation in accordance with Lippert-Mataga's prediction; however, in protic solvent, specific interactions are encountered. Fluorescence lifetime decay suggests a relaxation in the nanosecond time scale with monoexponential decay in polar solvents and biexponential decay in non polar solvents. The fluorescence lifetime of azacyanines are found to be longer than popular cy3 dyes. An electron donating substituent increases the fluorescence lifetime and influences the radiative process, whereas an electron withdrawing group marginally increases the excited state lifetime but remarkably enhances the radiative process. The fluorescence quantum yield of substituted cyclic azacyanine in water is noted to be at least five fold higher than the popular cy3 dye.

Original languageEnglish (US)
Pages (from-to)707-717
Number of pages11
JournalJournal of Fluorescence
Volume22
Issue number2
DOIs
StatePublished - Mar 2012

Keywords

  • Cyclic Azocyanine
  • Excited state process
  • Fluorescence lifetime
  • Radiative process
  • Solvent effect
  • Substituent effect

ASJC Scopus subject areas

  • Spectroscopy
  • Biochemistry
  • Clinical Biochemistry

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