Competition between Methoxy-Based and Pyrazine-Based Synthons in Methoxy-Substituted Distyrylpyrazines
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- 作者：Alain Collas ; Izabela Bagrowska ; Krzysztof Aleksandrzak ; Matthias Zeller ; Frank Blockhuys
- 刊名：Crystal Growth & Design
- 出版年：2011
- 出版时间：April 6, 2011
- 年：2011
- 卷：11
- 期：4
- 页码：1299-1309
- 全文大小：1154K
- 年卷期：v.11,no.4(April 6, 2011)
- ISSN：1528-7505
文摘
Four new methoxy-substituted derivatives of E,E-2,5-bis(2-phenylethenyl)pyrazine have been synthesized. The supramolecular structures of the resulting set of five polymorphs have been studied using single-crystal X-ray diffraction to gauge the influence of the position of the methoxy groups on the organization of the molecules in the solid state, as part of an attempt to dispense with the particular polymorphism of the parent compound. The crystal packing patterns were analyzed in terms of the two pyrazine-based synthons found in the parent compound鈥檚 crystal structure, the 蟺pyrazine路路路蟺phenyl stacking synthon, and the pyrazine hydrogen-bonded synthon, as well as in terms of weak intermolecular interactions such as CH路路路O, CH路路路N, and CH路路路蟺. The analysis shows that the introduction of methoxy groups in positions other than only the para position of the peripheral benzene rings successfully switches off the two synthons seen in the parent compound and that the new compounds adopt other packing strategies, based on methoxy路路路methoxy and 鈭扥CH3路路路蟺 contacts. Polymorphism, however, remains.