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.