Hydrogen-bonded organic frameworks: design, applications, and prospects

As a new type of porous crystalline material, hydrogen-bonded organic frameworks (HOFs) assemble through intermolecular hydrogen bonds of organic building blocks. The unique advantages of HOFs, such as high crystallinity, solution processability, and facile regeneration, have attracted great research attention, enabling new platforms for exploring multifunctional applications. Herein, we summarize basic principles and synthetic methods of constructing HOFs with favorable stability and permanent porosity. In addition, hydrogen bonding motifs (diaminotriazine (DAT), carboxylic acid (-COOH), sulfonic acid (-SO 3 H), and others) used to construct HOFs and some potential applications of HOFs are highlighted, including gas separation and storage, proton conduction, sensing and fluorescence detection, ultra-long phosphorescent materials, light luminescent materials, catalysis, etc. Finally, the prospects and challenges of HOFs in the future are discussed. Hydrogen-bonded organic frameworks (HOFs) are crystalline porous polymers which are formed by the interaction of hydrogen bonding among building blocks. Unique advantages of HOFs, enabling new platforms for exploring multifunctional applications.