Small Structural Changes in the Alkyl Substituents of Macrocyclic π-Extended Thiophene Oligomers Causes a Key Effect on Their Stacking and Functional Properties
| Autor: | Toshihiro Fujiwara, Masataka Takashika, Masashi Hasegawa, Yoshio Aso, Yutaka Ie, Shinobu Aoyagi, Masahiko Iyoda, Hiroyuki Otani |
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| Rok vydání: | 2019 |
| Předmět: |
chemistry.chemical_classification
010405 organic chemistry Stacking General Chemistry Crystal structure Random hexamer 010402 general chemistry 01 natural sciences 0104 chemical sciences chemistry.chemical_compound Crystallography Polymorphism (materials science) chemistry Thiophene Molecule Self-assembly Alkyl |
| Zdroj: | ChemPlusChem. 84(6) |
| ISSN: | 2192-6506 |
| Popis: | Three new macrocyclic π-extended thiophene hexamers composed of four thienylene-ethynylene and two thienylene-vinylene units with or without four alkyl substituents have been synthesized. Despite similar shape-persistent structures in solution, the alkyl substituents control the solid-state structures and morphologies. The unsubstituted hexamer exhibited a planar conformation with a theoretically predicted structure in the solid state; however, the planar hexamer with four ethyl substituents formed a closely stacked columnar crystal structure to exhibit π-π interactions. Interestingly, the hexamer with four butyl substituents adopted both planar and twisted conformations in the solid state, exhibiting polymorphism based on induced-fit stacking of molecules. Thus, the butyl-substituted hexamer produces a mixture of yellow, orange, and red single crystals from toluene/acetone, and X-ray analysis revealed six different conformations. Consequently, the small structural difference in the macrocycles causes a key effect on their functional properties in the solid state, and their morphology governs electrical conductivity and organic field-effect-transistor activity. The polymorphism of the hexamers was applied to the switching of film morphology. |
| Databáze: | OpenAIRE |
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