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Investigation of Tetherable Distilbazolium Compounds as Fluorescent Probes in Nanostructured Silica Sol‐gel Materials ¶
Author(s) -
Petrov E. P.,
Clchos F.,
Wagner F.,
Spange St.,
Borczyskowski C.
Publication year - 2005
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.2005.tb01460.x
Subject(s) - isomerization , solvation , silica gel , fluorescence , chemistry , solvent , sol gel , kinetics , photochemistry , stokes shift , nanopore , analytical chemistry (journal) , materials science , organic chemistry , catalysis , nanotechnology , physics , quantum mechanics
Distibazolium dyes are investigated by steady‐state and time‐resolved fluorescence techniques in a series of low‐ and highviscosity polar solvents and in a silica sol‐gel matrix. In all solvents and the sol‐gel matrix, an interplay of photoinduced switching between different cis‐trans isomers and solvation dynamics is observed. Even in a viscous solution (glycerol) and in silica gel, cis‐trans isomerization is solvent‐controlled. Whereas in glycerol the solvation results in a time‐dependent fluorescence Stokes shift, the solvation‐induced spectral heterogeneity in silica gel is mostly static, possibly due to a close proximity of dye molecules to the silica surfaces of the nanopores. Compared to low‐viscosity solvents, where the cis‐trans isomerization process takes place with a solvent‐dependent rate on the timescale of about 120–150 ps, it slows down to about 1100–1400 ps in glycerol and about 1500 ps in a sol‐gel matrix. Additionally, fluorescence kinetics of the dyes in the sol‐gel reveals the presence of a range of different “frozen‐in” conformers exhibiting a broad spectrum of lifetimes from 20 to 300 ps.