We have found that a homotrioxacalixarene (1H3) -based ionophore with a cone conformation, which is very difficult to obtain by the reaction of 1H3 and ethyl bromoacetate, can be synthesized quantitatively by the reaction of 1H3 and N,N-diethylchloroacetamide in THF in the presence of NaH. The conformer distribution of the tri-amide derivative (1Am3) between cone and partial-cone was sensitively affected in 0 ∼ 100% range by the metal template effects. Cone-1Am3 showed the very high affinity for alkali and alkaline earth metal cations. Particularly, it formed stable complexes with alkaline earth metal cations which were scarcely bound to the tri-ester derivative. The results show that cone-1Am3 acts as an excellent neutral ionophore owing to the three coordinative amide groups arranged in C3-symmetry.
All Science Journal Classification (ASJC) codes