Planar Chirality and Helical Polymers: Ferrocenyl-Substituted Amidinium鈥揅arboxylate Salts

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• 作者：Martyn P. Coles ; Francesca A. Stokes ; Benjamin F. K. Kingsbury ; Benjamin M. Day ; Peter B. Hitchcock
• 刊名：Crystal Growth & Design
• 出版年：2011
• 出版时间：July 6, 2011
• 年：2011
• 卷：11
• 期：7
• 页码：3206-3212
• 全文大小：974K
• 年卷期：v.11,no.7(July 6, 2011)
• ISSN：1528-7505

文摘

A series of amidinium鈥揷arboxylate salts, [FcC{N(Cy)H][O₂CR鈥测€瞉 (Fc = ferrocenyl, R鈥测€?= Me, ^tBu, Ph, mesityl, CF₃) have been synthesized and structurally characterized. In each case, the amidinium cation forms two NH路路路O hydrogen bonds to carboxylate anions. The extent of aggregation is, however, dependent on the carboxylate substituent. For R鈥测€?= Me, a 1:1 salt is observed with an {E,E}-configuration of cyclohexyl groups within the amidinium component, whereas R鈥测€?= ^tBu forms a 2:2 dimeric salt with an {E,Z}-cation. This latter configuration generates a planar chiral cation. When R鈥测€?= Ph or mesityl, the hydrogen-bonding forms a helical polymer, with each chain containing a single enantiomeric form of the cation. In contrast, when R鈥测€?= CF₃ the hydrogen-bonded polymer contains alternating enatiomeric forms of the cation.