Regiocontrolled Dimerization of Asymmetric Diazaheptacene Derivatives Toward X-shaped Porous Semiconductors
Conformationally rigid X-shaped PAHs are attracting interest due to their self-assembly into unique networks and as models to study through-space exciton and charge delocalization in one single molecule. We report here the synthesis of X-shaped PAHs by dimerization of diazaheptacene diimides. The diimide groups are employed to effectively direct the self-assembly into antiparallel dimer aggregates, which assist the compounds to undergo a regiocontrolled [4+4] dimerization, leading to X-shaped conformation bearing electron-poor and -rich subunits. The resulting PAHs are found to pack in 2D layers with large open channels and infinite π···π arrays. Furthermore, these high crystalline porous materials enable to serve as electron-transporting materials in OFET due to the long-range π-stacking arrays in the layers. This work presents a potentially generalizable strategy, which may provide a unique class of porous semiconductors for organic devices, taking advantage of their open channels.