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Thiepin‐Fused Heteroacenes: Simple Synthesis, Unusual Structure, and Semiconductors with Less Anisotropic Behavior
Author(s) -
Cai Zhengxu,
Zhang Hantang,
Geng Hua,
Liu Zitong,
Yang Sifen,
Luo Hewei,
Jiang Lang,
Peng Qian,
Zhang Guanxin,
Chen Jianming,
Yi Yuanping,
Hu Wenping,
Zhang Deqing
Publication year - 2013
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201302114
Subject(s) - intermolecular force , homo/lumo , atomic orbital , materials science , crystallography , crystal (programming language) , organic semiconductor , chemical physics , molecule , chemistry , physics , organic chemistry , optoelectronics , quantum mechanics , computer science , programming language , electron
Abstract The simple one‐pot syntheses of sulfur‐rich thiepin‐fused heteroacences with an alkylidene–fluorene framework, THA1 and THA6 (thiepin‐fused heteroacene 1 or 6, in which the thiepin is conjugated at both ortho positions with SCH 3 or SC 6 H 13 , respectively), is reported. Based on electrochemical studies and theoretical calculations, their LUMO energies are relatively low (−3.26 eV), and their HOMO and HOMO−1 orbitals are nearly degenerate. The thiepin ring contributes mainly to HOMO−1 and LUMO orbitals, however, HOMO orbitals dominantly reside on thienoacence rings. Within the crystal of THA1, the molecules adopt a herringbone arrangement and multiple intermolecular interactions lead to the formation of a 2D network. Interestingly, THA6 shows totally different intermolecular arrangements. Organic field‐effect transistor (OFET) devices show both compounds exhibiting p‐type semiconducting behavior. Thin films or microcrystals of THA1 possess relatively high hole mobility. Moreover, the mobilities of the microcrystal of THA1 along three directions are in the same order, thus the hole‐carrier transporting within the hexagonal‐plane of microcrystal of THA1 exhibits less anisotropic behavior. In comparison, both thin films and microrods of THA6 show low hole mobilities. This agrees well with the intermolecular arrangements and interactions within crystal of THA6. Further theoretical calculations reveal that significant intermolecular electronic coupling among HOMO−1 orbitals and sulfur atoms play an important role in intermolecular electronic coupling for THA1.