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Indexed by:期刊论文

Date of Publication:2007-02-05

Journal:JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY

Included Journals:SCIE

Volume:186

Issue:1

Page Number:85-92

ISSN No.:1010-6030

Key Words:boron-dipyrromethene dye; crystal structure; fluorescence quantum yield; photostability; cyclovoltammetry; intramolecular vibronic relaxation; internal conversion

Abstract:Two series of novel boron-dipyrromethene (BODIPY) dyes containing 8-phenyl groups have been synthesized and their spectral properties have been studied. Series 2 with four methyl groups at 1, 3,5,7-positions show much higher fluorescence quantum yields and extinction coefficients than series 1 (without methyl groups). The "push-pull" electronic effect caused by the methyl groups at 3 and 5 positions is a significant positive factor to the high quantum yields of 2. The X-ray structure analysis of 1c and 2c reveals that steric expulsion exists between the phenyl and adjacent two methyl groups. Moreover, the steric expulsion might block the intramolecular vibronic relaxation and internal conversion of the excited 2, which also contributes to their high fluorescence quantum yields. The substituent effects on photostability and redox potentials of these dyes have been discussed. (c) 2006 Elsevier B.V All rights reserved.