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Syntheses and photophysical properties of fluorescent dibenzofurans, a dibenzothiophene, and carbazoles substituted with benzoxazole and hydroxyl groups to produce excited state intramolecular proton‐transfer
Author(s) -
Kauffman Joel M.,
Litak Peter T.,
Boyko Walter J.
Publication year - 1995
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570320523
Subject(s) - chemistry , photochemistry , benzoxazole , carbazole , intramolecular force , fluorescence , dibenzothiophene , dibenzofuran , excited state , absorption (acoustics) , acylation , polystyrene , organic chemistry , catalysis , physics , polymer , quantum mechanics , nuclear physics , acoustics
Dibenzofurans, a dibenzothiophene, and carbazoles, each substituted with a 2‐benzoxazolyl group as well as an ortho ‐hydroxyl group, were synthesized to produce fluors with fluorescence due to excited‐state intramolecular proton‐transfer. The orientations for Friedel‐Crafts acylation of 3‐methoxydibenzothio‐phene and of the analogous carbazole were determined. The fluors displayed absorption peaks in the 330–385 nm region with molar extinction coefficients up to 57,000. Fluorescence quantum efficiencies of 0.17–0.44 were obtained at wavelengths that had peak values from 540–600 nm. The fluors are of potential use as wavelength shifters in scintillating polystyrene fibers.