119455-97-9Relevant academic research and scientific papers
Ion-Responsive Fluorescent Compounds, 2. Cation-Steered Intramolecular Charge Transfer in a Crowned Merocyanine
Bourson, Jean,Valeur, Bernard
, p. 3871 - 3876 (1989)
The dimethylamine group of DCM (4-dicyanomethylene-2-methyl-6--4H-pyran), a well-known merocyanine often used as a laser dye, has been replaced by a macrocycle (monoaza-15-crown-5) which acts also as an electron donating substituent.The resulting fluoroionophore (DCM-crown) has almost identical photophysical properties as DCM, but upon complexation by alkaline-earth-metal-cations, it undergoes drastic changes in absorption spectrum (hypsochromic shift and hypochromic effect) and fluorescence quantum yield (quenching), whereas the emission spectrum is only slightly blue-shifted and the fluorescence lifetime is almost unchanged.These effects which strongly depend on the charge density of the cation can be interpreted in terms of cation-steered reduction of the efficiency of tranfer from a nonemissive locally excited state to an emissive relaxed intramolecular charge-transfer state (RICT).
