Protonation tendencies of azaparacyclophanes. A thermodynamic and NMR study

Abstract

The interaction of hydrogen ions with the series of macrocyclic receptors 2,5,8-triaza[9]paracyclophane, 2,6,10-triaza [11] paracyclophane, 13,14,16,17-tetramethyl-2,6,10-triaza[11]paracyclophane, 14,15,17,18-tetramethyl-2,5,8,11-tetraaza [12] paracyclophane and 16,17,19,20-tetramethyl-2,6,9,13-tetraaza[14]paracyclophane has been studied by potentiometry at 298.1 ± 0.1 K as well as by direct microcalorimetry and ¹H and ¹³C NMR spectroscopy. Correlations of the basicity with the atomicity of the macrocycle, the type of chains within the bridge and the nature of the aromatic spacer are envisaged.