Crowned Ionic Liquids for Biomolecular Interaction Analysis.

On the basis of affinity recognition with positively charged side chains in peptides and proteins, a series of crowned 1,2,3-triazolium ionic liquids (CIL 1-6) was developed and found to be capable of quantitatively extracting peptides and proteins from the aqueous layer into the ionic liquid phase. All of the synthesized CIL 1-6 are liquid at room temperature. This is the first example of biomolecular recognition of both lysine- and arginine-containing peptides and proteins by CILs in pure ionic liquid phase.