Spectral and photophysical properties of intramolecular charge transfer fluorescence probe:: 4′-dimethylamino-2,5-dihydroxychalcone

The spectral and photophysical properties of a new intramolecular charge transfer (ICT) probe, namely 4'-dimethylamino-2,5dihydroxychalcone (DMADHC) were studied in different solvents by using steady-state absorption and emission spectroscopy. Whereas the absorption spectrum undergoes minor change with increasing polarity of the solvents, the fluorescence spectrum experiences a distinct bathochromic shift in the band position and the fluorescence quantum yield increases reaching a maximum before decrease with increasing the solvent polarity. The magnitude of change in the dipole moment was calculated based on the Lippert-Mataga equation. These results give the evidence about the intramolecular charge transfer character in the emitting singlet state of this compound. (c) 2005 Elsevier B.V. All rights reserved.