The binding properties of 1-7 towards Cl -were investigated by 1 H NMR titrations in THF-d8, using Pen4NCl as a titrant. In the case of 1, the addition of Pen4NCl resulted in large downfield shifts of Ha ( = + 1.9 ppm) and Hb signals directed towards the lower rim ( = +0.30 ppm), while the remaining signals were almost completely indifferent (Fig. ). In case of 2, Cl -binding shifted signals from Ha ( = + 1.7 ppm) and from the lower rim aliphatic hydrogens Hc ( = +0.6 ppm). Interestingly, large changes (+7 ppm) were also observed in the C NMR spectrum of 2, namely at the signal corresponding to the carbon atom involved in C-Hanion interaction. These changes indicate that for both 1 and 2, Cl -binding takes place in the lower rim, i.e. at the apex of the cone.