Weak C-H/pi interaction participates in the diastereoselectivity of a host-guest complex in the presence of six strong hydrogen bonds

structure: see text] We report a study of the interaction between methylmethanetriacetic acid (MMTA) and a tripodal amidopyridine receptor 1, where the geometry of the binding is in part governed by a weak C-H/pi interaction in the presence of six strong N(O)-H.O(N) hydrogen bonds. There are two possible binding geometries for the 1:1 complex 1.MMTA; combining computational and experimental evidence we demonstrate that the endo binding mode is more favorable as the result of a C-H/pi interaction.