Anion-Mediated Topology Control of Supramolecular Frameworks for Ultrahigh Iodine Capture

Abstract

Reticular chemistry enables the precise design and synthesis of crystalline extended materials, however, its application in hierarchical self-assembly of superstructures remains challenging due to the limited control over weak interactions between synthons, in contrast to the stronger coordination or covalent bonds typically involved. Herein, we introduce an anion-competitive strategy to control the topology and structural diversity of superstructures. Cationic tetrahedral Zr-based metal–organic polyhedra were used as cage-like synthons, which were charge-balanced by Cl^– ions and interconnected via hydrogen bonds to form hierarchical superstructures. Introducing trigonal planar NO₃^– ions to compete with spherical Cl^– ions produced three new superstructures featuring different hydrogen bond-based linkages and distinct topologies (dia, bnn, and xhy), diverging from the previously reported flu topology. Furthermore, the superstructures with dia and bnn topologies exhibit high porosities and record iodine adsorption capacities in solution (4.31 and 4.19 g·g^–1, respectively). This work demonstrates the potential of reticular chemistry for the versatile design and construction of diversified hierarchical superstructures.

Keywords

Hierarchical superstructure / Reticular chemistry / Anion-competitive strategy / Metal–organic polyhedra / Structural diversity / Iodine adsorption / Cage compounds / Isomers / Crystal engineering

RIGHTS & PERMISSIONS

2025 SIOC, CAS, Shanghai, & WILEY-VCH GmbH