Metal–Macrocycle Framework (MMF): Supramolecular Nano-Channel Surfaces with Shape Sorting Capability

Hollow nanostructures for the functional assembly of
chemical groups
with inner surface geometry and regulable stoichiometry enable steric
design of interior reaction centers. Herein we report a metal–macrocycle
framework (MMF) that forms single-crystalline nanochannels with five
distinct enantiomeric pairs of guest binding pockets. During crystal-soaking
experiments, the MMF crystals can encapsulate aromatic molecules with
high site selectivity. First, constitutional isomers of dibromobenzene
are captured and sorted into different binding pockets. Second, each
of the optical isomers of (1R/1S)-1-(3-chlorophenyl)­ethanol is included diastereoselectively into
one of an enantiomeric pair of binding pockets. An advantage of this
strategy is that the interior walls can be “repainted”
via replacement of the trapped molecules with alternatives. Such guest
uptake behaviors would allow highly regioselective or stereoselective
reactions within the nanochannel.