Guest exchange in a porous cucurbit[6]uril-based metal–organic rotaxane framework probed by NMR and X-ray crystallography

Abstract

The first CB[6]-based 3D porous metal–organic rotaxane framework is constructed by the reaction of CuCl₂, terephthalic (H₂BDC) and CB[6]-based [2]pseudorotaxanes ([PR44]²⁺·2[PF₆]⁻) under solvothermal conditions. The structure of MORF-1 is a pillared-layer structure with 5-connected sqp topology, in which the effective free volume is 45.4% of the crystal volume. The guest molecules exchange in a single-crystal-to-single-crystal fashion, which was investigated using NMR spectroscopy and X-ray crystallography.