Lateral Self-Assembly of 1D Supramolecular Columns into Ordered 2D Assemblies Enables In-Plane Hole Delocalization for Photocatalytic O2 Evolution

Abstract Organic supramolecular assemblies have emerged as attractive platforms for photocatalysis by bridging molecular-level design with ordered functional architectures. However, conventional one-dimensional columnar assemblies confine holes to linear transport pathways, where weak intercolumn coupling and defect trapping impede long-range delocalization and accumulation, ultimately limiting efficient photocatalytic O2 evolution. Here, we report a cooperative assembly strategy that transforms one-dimensional (1D) supramolecular columns into ordered 2D assemblies (2DA) through the synergy of hydrogen bonding and cation-π interactions to enhance intercolumn coupling for enhanced photocatalytic O2 evolution. First, a pyridinium-functionalized C3-symmetric triarylamine tris-amide monomer (M1) forms hydrogen-bonded supramolecular columns, which are then laterally coupled by cation-π interactions into ordered 2DA-1. This architecture strengthens intercolumn coupling through cation−π interactions between pyridinium and triphenylamine units, enabling in-plane hole delocalization and thereby promoting efficient charge separation and long-lived hole accumulation. As a result, 2DA-1 achieves an O2-evolution rate of 1.09 mmol g–1 h–1 and a maximum apparent quantum efficiency of 1.19% at 460 nm. This work establishes a structural strategy for transforming 1D supramolecular columns into efficient 2D photocatalytic architectures.