Room-Temperature Columnar Liquid Crystals from Twisted and Macrocyclic 9,9'-Bifluorenylidene Mesogen with Ambipolar Carrier Transport Properties.

We herein report the synthesis and characterization of a series of twisted and conjugated 9,9'-bifluorenylidene ( BF ) derivatives and a ladder-shaped cyclic dimer ( CBF ) bearing eight long alkoxy chains at peripheral positions. These contorted aromatics formed hexagonal columnar liquid crystalline mesophases over a wide temperature range, including room temperature. Ambipolar carrier transport properties with electron and hole mobility values of approximately 10 -4 and 10 -5 cm 2 V -1 s -1 , respectively, were achieved for the BF derivatives forming a monodomain orientation at ambient temperature.