Structure and dynamics in columnar discotic materials:: A combined X-ray and solid-state NMR study of hexabenzocoronene derivatives

The solid columnar discotic and liquid crystalline (LC) phases formed by alkyl-substituted hexabenzocoronene (HBC) mesogens have been investigated by a combination of X-ray scattering and a variety of advanced solid-state NMR methods. Correlations between chemical structure, molecular packing and dynamics are established. Maximum charge carrier mobility is observed for a crystal-like stacking of the disks in the column with optimized pi-pi interactions. For systems with lower intracolurnnar order the charge carrier mobility is slightly lower and slow axial motion of the disks around the column axes occurs.