Arrangement Modulation of π-Stacked Columnar Assemblies of Octadehydrodibenzo[12]annulene: Substituent Effects of Peripheral Thienyl and Phenyl Rings

Introduction of rigid aryl substituents into the periphery of a π-conjugated molecule changes its assembly manner from that of the parent compound, resulting in drastic changes of optical and electrical properties of the assembly. In this study, we revealed that ortho-thienyl substituted octadehydrodibenzo[12]annulene derivative 2 yielded two types of crystal structures with zigzag and one-dimensionally (1D) π-stacked motifs. Their thermal, optical, and electrical properties were investigated. Furthermore, we demonstrate that although the phenyl- and thienyl-substituted derivative (1 and 2, respectively) yielded closely resembled 1D π-stacked columns in their crystals (1-column and 2-II, respectively), arrangements of the columns are completely different due to subtle differences of the substituents. Such differences in the arrangements drastically affect the lifetime of charge carrier generated in crystals, although the intensity of the photoconductivity is almost the same in both crystals. These results...