Photophysical and photochemical characteristics of an azlactone dye in sol-gel matrix; a new fluorescent pH indicator

ERTEKİN K., Karapire C., ALP S., Yenigül B., Içli S.

Dyes and Pigments, vol.56, no.2, pp.125-133, 2003 (SCI-Expanded, Scopus) identifier identifier

  • Publication Type: Article / Article
  • Volume: 56 Issue: 2
  • Publication Date: 2003
  • Doi Number: 10.1016/s0143-7208(02)00125-0
  • Journal Name: Dyes and Pigments
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.125-133
  • Keywords: azlactone, fluorescence emission, sol-gel, optical pH sensor, fluorescent pH indicator
  • Manisa Celal Bayar University Affiliated: No

Abstract

The photophysical and photochemical properties of an azlactone derivative, 4-(p-N,N-dimethylaminophenylmethylene)-2-phenyl-5-oxazolone, (DPO) in a sol-gel matrix have been examined. The fluorescence quantum yield, radiative lifetime, fluorescence lifetime, fluorescence rate constant and singlet energy values of the DPO dye were determined in a modified tetraethyl orthosilicate (TEOS) solid matrix by absorption and emission spectroscopy and obtained data were compared with the results of measurements in acetonitrile (MeCN) and tetrahydrofuran (THF) solution. The sol-gel matrix enhanced the fluorescence quantum yield (Qf=0.296) and fluorescence emission lifetime (τf=0.47 ns) compared to Qf=0.0027-0.0025 and τf=0.02-0.03 ns for solutions in MeCN and THF. The acidity constant of DPO was found to be as pKa=5.1 in the transparent sol-gel matrix. The dye doped sol-gel exhibited a pH sensitivity in pH range 3.0-7.0. © 2002 Elsevier Science Ltd. All rights reserved.