Rational design of a colorimetric and ratiometric fluorescent chemosensor based on intramolecular charge transfer (ICT)

A simple colorimetric and ratiometric fluorescent anion sensor 1,3,6-dichloro-1,8-dinitrocarbazole, was rationally designed and synthesized on basis of the mechanism of intramolecular charge transfer (ICT). In DMSO solutions of 1, the presence of ACO(-), F- and H2PO4- gave birth to the formation of a 2:1 host-to-guest complex, which was synchronously accompanied by a 'naked-eye' color change from light yellow to purple, a red-shift of the absorption spectrum and a blue-shift of the emission spectrum. (c) 2008 Elsevier B.V. All rights reserved.