Noncovalent interaction guided selectivity of haloaromatic isomers in a flexible porous coordination polymer

Porous, supramolecular structures exhibit preferential encapsulation of guest molecules, primarily by means of differences in the order of (noncovalent) interactions. The encapsulation preferences can be for geometry (dimension and shape) and the chemical nature of the guest. While geometry-based sorting is relatively straightforward using advanced porous materials, designing a chemical nature specific host is not. To introduce chemical specificity, the host must retain an accessible and complementary recognition site. In the case of a supramolecular, porous coordination polymer (PCP) [Zn(o-phen)(ndc)] (o-phen: 1,10-phenanthroline, ndc: 2,6-naphthalenedicarboxylate) host, equipped with an adaptable recognition pocket, we have discovered that the preferential encapsulation of a haloaromatic isomer is not only for dimension and shape, but also for the chemical nature of the guest. This selectivity, i.e., preference for the dimension, shape and chemical nature, is not guided by any complementary recognition site, which is commonly required for chemical specificity. Insights from crystal structures and computational studies unveil that the differences in the different types of noncovalent host-guest interaction strengths, acting in a concerted fashion, yield the unique selectivity. Porous, supramolecular structures exhibit preferential encapsulation of haloaromatic isomers, primarily by means of differences in the order of (noncovalent) interactions.

Automated summary

Porous, supramolecular structures can selectively encapsulate guest molecules by exploiting differences in noncovalent interactions. The encapsulation preferences are influenced by the geometry and chemical nature of the guest molecules. Designing a host with chemical specificity requires an accessible and complementary recognition site. However, in the case of a supramolecular, porous coordination polymer (PCP), the selectivity for a haloaromatic isomer is not only based on geometry and shape, but also on the chemical nature of the guest, without relying on a complementary recognition site.