Luminescent properties of chalcone and its aminoderivatives

Dipole-dipole interactions are shown to stabilize the excited Sππ⁎ state in the systems studied in the same way as for others heteroaromatic luminophores. Specific interactions in protic solvents cause in addition significant geometry deformation to the non-planar structure of the chromophore. Large intramolecular spin-orbit coupling between the lowest singlet and triplet excited states in the latter case is revealed. It proves that intersystem crossing between these states should be the main channel of fluorescent quenching of 4-(N,N′-dimethylamino)-chalcone in protic solvents.