Ramnial Taramatee, Taylor Stephanie A, Bender Marissa L, Gorodetsky Brian, Lee Peter T K, Dickie Diane A, McCollum Brett M, Pye Cory C, Walsby Charles J, Clyburne Jason A C
Department of Chemistry, Simon Fraser University, Burnaby BC, V5A 1S6, Canada.
J Org Chem. 2008 Feb 1;73(3):801-12. doi: 10.1021/jo701289d. Epub 2008 Jan 4.
Phosphonium ionic liquids (PhosILs), most notably tetradecyl(trihexyl)phosphonium decanoate (PhosIL-C(9)H(1)9COO), are solvents for bases such as Grignard reagents, isocyanides, Wittig reagents (phosphoranes), and N-heterocyclic carbenes (NHCs). The stability of the organometallic species in PhosIL solution is anion dependent. Small bases, such as hydroxide, react with the phosphonium ions and promote C-H exchange as suggested by deuterium-labeling studies. A method to dry and purify the ionic liquids is described and this step is important for the successful use of basic reagents in PhosIL. NHCs have been generated in PhosIL, and these persistent solutions catalyze organic transformations such as the benzoin condensation and the Kumada-Corriu cross-coupling reaction. Phosphoranes were generated in PhosIL, and their reactivity with various organic reagents was also tested. Inter-ion contacts involving tetraalkylphosphonium ions have been assessed, and the crystal structure of [(n-C(4)H(90)(4)P][CH(3)CO(2).CH(3)CO(2)H] has been determined to aid the discussion. Decomposition of organometallic compounds may also proceed through electron-transfer processes that, inter alia, may lead to decomposition of the IL, and hence the electrochemistry of some representative phosphonium and imidazolium ions has been studied. A radical derived from the electrochemical reduction of an imidazolium ion has been characterized by electron paramagnetic resonance spectroscopy.
鏻离子液体（PhosILs），最显著的是十四烷基（三己基）鏻癸酸酯（PhosIL-C(9)H(1)9COO），是格氏试剂、异腈、维蒂希试剂（磷叶立德）和N-杂环卡宾（NHCs）等碱的溶剂。有机金属物种在PhosIL溶液中的稳定性取决于阴离子。小分子碱，如氢氧化物，会与鏻离子反应，并如氘标记研究所表明的那样促进C-H交换。描述了一种干燥和纯化离子液体的方法，这一步骤对于在PhosIL中成功使用碱性试剂很重要。NHCs已在PhosIL中生成，这些稳定的溶液催化有机转化反应，如安息香缩合反应和 Kumada-Corriu 交叉偶联反应。磷叶立德已在PhosIL中生成，并且还测试了它们与各种有机试剂的反应性。评估了涉及四烷基鏻离子的离子间接触，并确定了[(n-C(4)H(90)(4)P][CH(3)CO(2).CH(3)CO(2)H]的晶体结构以辅助讨论。有机金属化合物的分解也可能通过电子转移过程进行，这尤其可能导致离子液体的分解，因此研究了一些代表性鏻离子和咪唑离子的电化学。通过电子顺磁共振光谱对由咪唑离子的电化学还原产生的自由基进行了表征。
