Ionic liquids from heterocycles, reviews

Thus, most ionic liquids are formed from cations that do not contain acidic protons. A summary of the applications and properties of ionic liquids may be found in a number of recent review articles [3]. The most common classes of cations are illustrated in Figure 2.1-1, although low melting point salts based on other cations, such as complex poly cationic amines [4] and heterocycle-containing drugs [5], have also been prepared. 

In this review, the use of N-heterocyclic carbene complexes derived from imidazoHum salts as a part of the different strategies involving ionic liquids has not been considered. Nevertheless, it can be important to take into account this reactivity, especially when 1,3-dialkylimidazolium ILs are involved. For more details about this aspect and applications in hydroformylation, one can refer to Herrmanrfs recent review [55] and the later publication of Poyatos et al. in 2003 [56]. 

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