Calix[4]pyrroles with bulky substituents and their anion binding studies

摘要

Calix[4]pyrrole derivatives with bulky substituents at their meso -positions were synthesized via mixed condensation of pyrrole with cyclohexanone and acetophenone derivatives. Anion binding studies, carried out by isothermal titration calorimetry in 1,2-dichloroethane with Cl$^{-}$ and CH$_{3}$CO$_{2}^{-}$ anions in the form of their tetrabutylammonium salts, revealed that these new calix[4]pyrrole derivatives can bind the aforementioned anions as effectively as the unsubstituted ''parent'' system, octamethylcalix[4]pyrrole ( 1 ). Structural characterizations of new calix[4]pyrroles were carried out by using $^{1}$H and $^{13}$C NMR spectroscopy corroborated with mass spectrometry.