Arrangement Modulation of π‑Stacked Columnar Assemblies of Octadehydrodibenzoannulene: Substituent Effects of Peripheral Thienyl and Phenyl Rings
journal contributionposted on 10.02.2016 by Ichiro Hisaki, Keisuke Osaka, Nobuaki Ikenaka, Akinori Saeki, Norimitsu Tohnai, Shu Seki, Mikiji Miyata
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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 octadehydrodibenzoannulene 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 can provide a new insight for tuning of the assembly’s properties by changing the peripheral aryl substituents of π-conjugated molecules.