Fully-substituted 1,3-Butadienes as π-Conjugated Linkers between Pyrenes

Pyrenyl-substituted 1,3-butadienes bearing alkyl and aryl groups have been synthesized by palladium-catalyzed addition of 2-borylpyrene to internal alkynes. On UV irradiation, 1-pyrenylbutadienes undergo photochromism in solution. In the solid state, 1-pyrenyl-1,2,3,4-tetraaryl-1,3-butadiene exhibits red-shifted and broad emission as compared with the alkylated butadiene. The charge-carrier mobility of 1-pyrenyl-1,2,3,4-tetraalkyl-1,3-butadiene is higher than that of the arylated butadiene.