Metal-containing ionic liquids: current paradigm and applications

Metal-containing ionic liquids have been known for several decades and the scope of their applicability is currently extending. The review briefly considers four key types of these ionic liquids, namely, ionic liquids containing a metal atom in the cation and/or anion; a metal atom or a metal complex coordinated to the cation or anion; a dissolved metal salt or complex; and metal or metal oxide nanoparticles. The use of metal-containing ionic liquids in organic synthesis is considered, including cyclization and isomerization, alkylation, carbonylation, metathesis and $\mathrm{C}$–$\mathrm{C}$ coupling reactions. In particular, isobutane alkylation with but-2-ene underlies the production of high-octane fuel. Particular sections are devoted to the use of metal-containing ionic liquids for fuel desulfurization and denitrogenation and for electrodeposition. Promising applications of these materials in biomedicine, biomass refining, $\mathrm{CO}_2$ capture and design of new soft materials are outlined.
The bibliography includes 215 references.