Synthesis, Crystal Structure, and Photophysical Properties of 4-(4-(Dimethylamino)phenyl)-6-phenylpyrimidin-2-amine

The pyrimidine core is present in a wide variety of compounds that show interesting fluorescent properties and have been used as pigments and dyes. In this research, we synthesized 4-(4-(dimethylamino)phenyl)-6-phenylpyrimidin-2-amine (compound 9) from chalcone (8) with 45% yield. We obtained monocrystals of 9 by slow evaporation of dichloromethane as a solvent. Additionally, we measured the photophysical properties of compound 9, and its absorption wavelength (λabs), molar absorption coefficient (e), excitation wavelength (λexc) and emission wavelength (λem), as well as Stokes shift (Δλ), increase with increasing solvent polarity. These properties are all related to the stabilization of the excited state by the solvent. On the other hand, the quantum yields (Φ values) in toluene and CH2Cl2 were notable greater than those in other solvents due to their high optical density (OD) and the decrease in the loss of fluorescence by non-radiative processes