Tagging of Active Catalysts

The modified catalyst is insoluble in conventional organic solvents but totally miscible with imidazolium-containing ionic liquids. The catalyst showed high activity for the cyanosilylation of aldehydes and, as expected, remained isolated in the ionic liquid phase after use (for more details, see Section V.A.12). 

Another example is the ionic tagging of a ruthenium carbene catalyst for ringclosing alkene metathesis. A [-(CH2)4-MIM] PF6 moiety was built into the structure of the catalyst, which enabled the long-term retention of the catalyst in the [BMIM]PF6 ionic liquid for multiple recycles (188). 

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