Photophysical properties, excitation energy transfer and laser activity of 3-(4′-dimethylaminophenyl)-1-(2-pyridinyl) prop-2-en-1-one (DMAPP): A new potential laser dye

The photophysical properties such as singlet absorption, molar absorptivity, fluorescence spectra, fluorescence quantum yield (ϕf) and transition dipole moment (μ12) of 3-(4′-dimethylaminophenyl)-1-(2-pyridinyl) prop-2-en-1-one (DMAPP) were measured in different media. DMAPP dye exhibits a large red shift in both absorption and emission spectra as solvent polarity increases, indicating a large change in dipole moment of molecule upon excitation. Also, the fluorescence quantum yield is solvent dependent. A crystalline solid of DMAPP gives excimer like emission at 585 nm. Dye solution ca 1 × 10−3 mol dm−3 in CHCl3 gives a good laser emission in the range 440–600 nm with emission maximum at 550 nm upon pumping by nitrogen laser (λex = 337.1 nm). The excitation energy transfer from 7-dimethylamino-4-methyl coumarine (DMC) to DMAPP has also been studied in CHCl3 and the value of energy transfer and critical transfer distance indicate a Főrster-type mechanism. The photochemical quantum yields (ϕc) of DMAPP in chloromethane solvents are also determined.