Release Time:2019-03-09  Hits:

Indexed by: Journal Article

Date of Publication: 2009-09-01

Journal: DYES AND PIGMENTS

Included Journals: Scopus、EI、SCIE

Volume: 82

Issue: 3

Page Number: 396-400

ISSN: 0143-7208

Key Words: Synthesis; Squaric acid; Cyanine dye; Squarylium dye; Photostability; Water-solubility

Abstract: Novel, water-soluble, squarylium indocyanine dyes with various N-substituents on 3H-indolenine were synthesized. The maxima of absorption and emission wavelengths of the dyes in different solvents were in the range 628-670 nm and exhibited negative solvatochromism with increasing solvent polarity in protic solvents. Dyes with N-benzyl rings (such as N-benzyl, N-carboxylbenzyl and N-fluorobenzyl) displayed greater photostability than dyes containing N-alkyl groups (such as N-ethyl and N-carboxylpentanyl) in aqueous solution. The electron-withdrawing group (such as carboxyl and fluoro group) on the N-benzyl group of cyanine dyes improved photostability compared to dyes that contained an electron-donating group (such as methyl). The fading constant k of the N-carboxylbenzyl dye was considerably lower than that of the N-carboxylpentanyl dye. (C) 2009 Elsevier Ltd. All rights reserved.