Effect of protonation on the photophysical properties of 4-substituted and 4,7-disubstituted quinazoline push-pull chromophores

White-light emission from single molecular systems has attracted a great deal of attention due to their advantages over multicomponent emitters. Azaheterocyclic push-pull derivatives have been demonstrated to be white emitters by combining neutral and protonated forms in the appropriate ratio, although limited cases of white light emission have been reported from quinazoline derivatives. Herein, we describe a series of push-pull 4-substituted and 4,7-disubstituted quinazolines that show white photoluminescence both in solution and in the solid state. All of the materials were prepared by straightforward Suzuki-Miyaura cross-coupling reactions and the compounds exhibited remarkable emission solvatochromism. In some cases the presence of acid prompted the appearance of emission bands of complementary colors. Thus, multicolor photoluminescence, including white light, could be finely tuned by the controlled protonation of the electron-deficient quinazoline ring.