Synthesis and photophysical properties of 2,1,3-benzothiadiazole-cored H-shaped conjugated compounds

Abstract We synthesized H-shaped conjugated compounds T1, T2, TP2 and P2, in which 2,1,3-benzothiadiazole was used as the core, and triphenylamine as well as phenothiazine was employed as the terminal group. It was found that they emitted red light in toluene excited either by the light of ca. 400 nm or by the femtosecond pulsed laser of 820 nm, meaning that the obtained 2,1,3-benzothiadiazole-based compounds exhibited two-photon absorption (TPA) activities. The results suggested that the strong electron donating ability of the donor, enlarged conjugation, branched and unsymmetrical structures favored the increasing of TPA abilities of the dyes.