Resorcarenes in the Boat Conformation as Building Blocks for Hydrogen-Bonded Assemblies Including Two Ammonium Cations

Publisher Website
Google Scholar
Abstract
Crystal structures are reported for various co‐crystals of rccc‐resorcarenes with triethylammonium chloride. Usually, two molecules of a C2v‐symmetric tetraester 2 in the boat conformation are linked through four hydrogen‐bonded chloride anions to give dimeric assemblies. Two of the chloride anions may be replaced by four hydrogen‐bonded ethanol molecules in an otherwise similar structure. These assemblies, which consist of six or eight components, posses voluminous, negatively charged chambers in which two triethylammionium cations, 3+, are included as guests by strong electrostatic and hydrogen‐bonding interactions. The host–guest N−H⋅⋅⋅Cl hydrogen bonds were clearly detected at 173 K. These are the first examples of hydrogen‐bonded, solid‐state capsules trapping two ions of the same charge in close proximity. In the 1:2 complex with 3+Cl−, the molecule of the parent resorcarene 1 also adopts a boat conformation whose cavity is considerably extended by four hydrogen‐bonded chloride anions. The pocket formed in this way again includes two 3+ ions as a result of electrostatic and hydrogen bonding host–guest interactions. All these structures show that the boat conformers of resorcarenes can be used as a novel motif for the construction of hydrogen‐bonded assemblies capable of molecular inclusion and encapsulation.

This publication has 59 references indexed in Scilit: