Emergent Molecular Weaving in an Ionic Metal-Organic Network for CO2 Conversion.

Abstract

Molecular weaving has emerged as a powerful design strategy in supramolecular chemistry, yet most woven frameworks rely on rigid ligands and elaborate templating. Here, we report a minimalistic, aqueous-phase synthesis of a woven metal-organic superstructure assembled from Cu2+ and 2,4,6-trinitrobenzene-1,3,5-triol (TNPG). In the crystal, asymmetric coordination of TNPG with Cu2+ yields charged one-dimensional (1D) polymeric strands featuring both distorted octahedral and square planar geometries. These strands interlace at a specific angle to form a two-dimensional (2D) woven architecture, a rare 1D─1D topological weaving stabilized by hydrogen bonding. The structure also incorporates discrete Cu2+ cationic complexes, where metal coordination significantly perturbs the aromatic π-conjugated system of TNPG. These cationic units are tethered within the network through strong hydrogen bonding and electrostatic attraction to the anionic woven strands, contributing to the structural integrity of the superstructure. Given the redox-active Cu2+ centers, electronically modulated ligand environment, and framework stability, the Cu-TNPG network was evaluated for visible-light-driven CO2 reduction. The photocatalytic performance of Cu-TNPG originates from its high charge separation efficiency and abundant catalytically active sites. Moreover, mild thermal pre-activation led to enhanced CO evolution efficiency through structural modulations, with a selectivity of ∼85% for CO over H2, highlighting its structural and functional versatility.