Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 2011-01-01

The synthesis and spectral properties of a stimuli-responsive D-π-A charge transfer dye.

Sung-Hoon Kim, Seon-Yeong Gwon, Jin-Seok Bae, Young-A Son

Index: Spectrochim. Acta. A. Mol. Biomol. Spectrosc. 78(1) , 234-7, (2011)

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Abstract

A new donor-π-acceptor (D-π-A) type isophorone dye was synthesized by the condensation reaction between 2-(3,5,5-trimethylcyclohex-2-enylidene)-malononitrile and indole-3-carboxaldehyde. The chemical structure of the dye was characterized by 1H NMR, EA and MS. A novel, chromogenic, fluorescent dye based on indol as donor unit and isophorone as acceptor unit displayed marked UV-visible absorption changes and highly selective fluorescence quenching in the presence of fluoride ion. The dye also exhibited sizeable colour changes when used as a pH-induced molecular switch and as a detector for volatile organic compounds. The absorption and fluorescent intensity of the dye can be reversibly selected by protonation/deprotonation of the amine moiety via control of intramolecular charge transfer (ICT), leading to a molecular switch with "on" and "off" states.Copyright © 2010 Elsevier B.V. All rights reserved.