Separation of Arylenevinylene Macrocycles with a Surface-Confined Two-Dimensional Covalent Organic Framework

Reticular Synthesis of One-Dimensional Covalent Organic Frameworks with 4-c sql Topology for Enhanced Fluorescence Emission

Covalent organic frameworks (COFs) have been extensively investigated due to their unique structure, porosity, and functionality. However, at the topological level, COFs remain as two-dimensional (2D) or three-dimensional (3D) structures, while COFs with one-dimensional (1D) topology have not been systematically explored. In this work, we proposed a synthetic strategy for the construction of 1D-COFs based on non-linear edges and suitable high-symmetry vertices. Compared with their 2D-COFs counterparts, the 1D-COFs with AIEgens located at the vertex of the frame exhibited enhanced fluorescence. The density functional theory (DFT) calculations revealed that the dimensional-induced rotation restriction (DIRR) effect could spontaneously introduce additional non-covalent interactions between the strip frames, which could substantially diminish non-radiative transitions. This work also provides protocols for the design of 1D-COFs and a guidance scheme for the synthesis of emitting COFs.

A C-N Coupling Polymerization on Ice-Surface towards Decimeter-Sized 2D Covalent Materials with High Catalytic Activity for Water-Splitting

Compared to other solid templates (metal, ceramic, carbon, etc.), polymerization on ice-surface has many advantages. However, the popularity of this method has been impeded by the lack of appropriate polymerization reactions. To date, only few oxidation polymerizations have been reported to occur on ice-surface, and unfortunately they can only produce supramolecular films rather than fully covalent films. Herein for the first time, 2D covalent materials have been created on ice-surface even at -16 °C through a C-N coupling polymerization, and two free-standing 2D polyarylamines (2DPA)s were synthesized. Both 2DPAs have decimeter-size and nanometer thickness. This study provides the first polymerization reaction to synthesize 2D covalent materials on ice-surface, which can be used to fabricate materials/tools/robots with specific 2D structure by copying ice morphologies. Furthermore, both 2DPAs exhibit higher hydrogen evolution reaction activity than many metal-free catalysts and even some metal-based catalysts, so this study also provides further insight for the development of metal-free catalysts for water-splitting.