DFT Study for Calix(4)tube Complexed with Alkali Metal Ion

Using DFT B3LYP/6-31G(d,p) calculation method, stable molecular structures were optimized for the p-tert-butylcalix[4]tube (1) and its alkali-metal-ion complexes. Sodium ion gave 15∼20 kcal/mol better complexation efficiency than the potassium cation toward 1 in both poly-ether tube (exo) and benzene-rings pocket (endo). For two different kinds of complexation mode, the alkali-metal-ion in exo-tube showed much better complexation efficiency than the cation in endo-pocket of 1.