Department of Sustainable Chemistry and Technology, SynBioC Research Group, Ghent University, Coupure Links 653, 9000 Ghent (Belgium), Fax: (+32) (9) 264 59 57.
Chemphyschem. 2013 Oct 21;14(15):3503-16. doi: 10.1002/cphc.201300611. Epub 2013 Sep 23.
Novel peralkylated imidazolium ionic liquids bearing alkoxy and/or alkenyl side chains have been synthesized and studied. Different synthetic routes towards the imidazoles and the ionic liquids comprising bromide, iodide, methanesulfonate, bis(trifluoromethylsulfonyl)imide (NTf2), and dicyanamide {N(CN)2} as the anion were evaluated, and this led to a library of analogues, for which the melting points, viscosities, and electrochemical windows were determined. Incorporation of alkenyl moieties hindered solidification, except for cations with high symmetry. The alkoxy-derivatized ionic liquids are often crystalline; however, room-temperature ionic liquids (RTILs) were obtained with the weakly coordinating anions NTf2 and N(CN)2. For the viscosities of the peralkylated RTILs, an opposite trend was found, that is, the alkoxy derivatives are less viscous than their alkenyl-substituted analogues. Of the crystalline compounds, X-ray diffraction data were recorded and related to their molecular properties. Upon alkoxy substitution, the electrochemical cathodic limit potential was found to be more positive, whereas the complete electrochemical window of the alkenyl-substituted imidazolium salts was shifted to somewhat more positive potentials.
已经合成并研究了具有烷氧基和/或烯基侧链的新型全烷基化咪唑鎓离子液体。评估了不同的咪唑和包含溴化物、碘化物、甲磺酸盐、双（三氟甲基磺酰基）亚胺(NTf2)和二氰胺{N(CN)2}作为阴离子的离子液体的合成途径，这导致了一系列类似物，测定了它们的熔点、粘度和电化学窗口。烯基部分的掺入阻碍了固化，除非阳离子具有高对称性。烷氧基衍生的离子液体通常是结晶的；然而，具有弱配位阴离子NTf2和N(CN)2的室温离子液体（RTILs）得到了。对于全烷基化 RTILs 的粘度，发现了相反的趋势，即烷氧基衍生物的粘度低于其烯基取代类似物。对于结晶化合物，记录了 X 射线衍射数据，并将其与分子性质相关联。在烷氧基取代后，发现电化学阴极极限电位变得更正，而烯基取代的咪唑盐的整个电化学窗口则向更正的电位移动。
