The synthesis, characterization and properties of coumarin-based chromophores containing a chalcone moiety

A series of coumarin-based derivatives containing a chalcone moiety were synthesized by condensation of 3-acetyl coumarins with aryl or heteroaryl aldehydes in the presence of piperidine in ethanol under microwave irradiation. Structures were established on the basis of 1H NMR, IR, MS and elemental analyses while crystal structure was determined using X-ray diffraction. Absorption and emission spectra showed red-shifts according to the strength of the electron-donating moieties and conjugation length. Replacement of a carbazolyl donor with a triphenylamine group in the coumarinyl-based chromophores resulted in a strong bathochromic shift (1700–1900 cm−1), while the benzocoumarin system caused a bathochromic effect of ∼100–500 cm−1 relative to the coumarin system.