An Adaptive Resorcinarene Hemicarcerand

Abstract

A new resorcinarene-based hemicarcerand was developed, exhibiting pronounced flexibility in size and shape to accommodate several guest molecules. With a series of seven hemicarceplexes, investigated via single-crystal XRD, the cage molecule showed to align its guests to complement their electrostatic potentials and to adjust its dimensions, according to the guest molecule‘s demand. Though forming equimolar inclusion complexes with most guests, crystallization from chloroform, and benzonitrile produced hemicarceplexes with a guest/host ratio of 2 : 1, exhibiting packing coefficients as high as 91 %. In competition experiments, the hemicarcerand clearly favors p-xylene over m-xylene: The host shows to crystallize, solely incarcerating p-xylene from a 1 : 1 mixture of the two xylenes, and also isolates p-xylene from the mixture via amorphous precipitation.