Chemistry Letters, Vol.33, No.3, 320-321, 2004
First application of calixarenes as extractants in room-temperature ionic liquids
We synthesized a calix[4]arene bearing pyridine, which has a similar molecular structure to the constitutional unit of 3-methylimidazolium hexafluorophosphate-based room-temperature ionic liquids. The pyridinocalix[4]arene was found to be soluble in ionic liquids, and this compound showed 230-fold extractability in ionic liquid over that in chloroform for silver ions.