Wang Ruihu, Xiao Ji-Chang, Twamley Brendan, Shreeve Jean'ne M
Department of Chemistry, University of Idaho, Moscow, Idaho 83844-2343, USA.
Org Biomol Chem. 2007 Feb 21;5(4):671-8. doi: 10.1039/b616529j. Epub 2007 Jan 12.
The reactions of 2-(2-pyridyl)imidazole with alkyl iodides at 25 degrees C in the presence of base gave rise to 1-alkyl-2-(2-pyridyl)imidazole. Subsequent neat reactions with alkyl or polyfluoroalkyl halides at 100 degrees C, followed by anion exchange with LiN(SO(2)CF(3))(2), generated the mono-quaternary ionic liquids. All of them have excellent thermal stability and wide liquid range. Most of the salts with asymmetric N-substituents are liquid at room temperature. The effect of N-substituent variation and symmetry on NMR, TGA and DSC is discussed. Reaction of with palladium(II) chloride produced a mononuclear palladium ionic liquid complex, the structure of which was confirmed by single-crystal X-ray diffraction analysis. The Heck cross-coupling reactions using in ionic liquid demonstrated excellent stability and recyclability.
2-(2-吡啶基)咪唑在25℃下于碱存在的条件下与烷基碘反应生成1-烷基-2-(2-吡啶基)咪唑。随后在100℃下与烷基或多氟烷基卤化物进行纯反应，接着用LiN(SO(2)CF(3))(2)进行阴离子交换，生成了单季铵离子液体。它们都具有优异的热稳定性和较宽的液体范围。大多数具有不对称N-取代基的盐在室温下为液体。讨论了N-取代基变化和对称性对核磁共振、热重分析和差示扫描量热法的影响。与氯化钯(II)反应生成了一种单核钯离子液体配合物，其结构通过单晶X射线衍射分析得以确证。在离子液体中进行的Heck交叉偶联反应表现出优异的稳定性和可回收性。
