Highly cooperative ion-pair recognition of potassium cyanide using a heteroditopic ferrocene-based crown ether-trifluoroacetylcarboxanilide receptor

A heteroditopic receptor having crown ether and trifluoroacetylcarboxanilide groups selectively recognizes both potassium and cyanide ions in acetonitrile with an association constant of as high as K-a = 1.9 x 6 10(7) M-1 through a highly cooperative ion-pair interaction, resulting in two orders of magnitude enhancement in the binding affinity.