Crystal Engineering of Biphenylene-Containing Acenes for High-Mobility Organic Semiconductors

Herein we report the synthesis, crystal structures, and semiconductor properties of new derivatives of bisnaphtho­[2′,3′:3,4]­cyclobut­[1,2-b:1′,2′-i]­anthracene (BNCBA). It is found that the π–π stacking of BNCBA in single crystals can be largely modified by alkyl substituting groups of different lengths. In particular, the tetrahexyl derivative exhibits π–π stacking with an unusual zigzag arrangement. The variation of molecular packing also leads to a change in charge transport characteristics as found from the theoretical calculation of mobility on the basis of single-crystal structures. All of these BNCBA derivatives function as p-type semiconductors in solution-processed thin film transistors, and the tetrahexyl derivative exhibits a field effect mobility as high as 2.9 cm2/(V s).