Novel breakthrough in the synthesis, functionalization, morphology, properties, and applications of hydrogen-bonded organic frameworks

Abstract

Hydrogen-bonded organic frameworks (HOFs) are porous crystalline materials due to their excellent crystallinity, solution processability, and ease of regeneration, making them well-suited for multifunctional applications. Despite these advantages, some HOFs become unstable after desolvation, presenting challenges related to stability, porosity, and functionalization. Recent advancements have enhanced HOFs stability through strategies like stronger charge-assisted hydrogen bonds and coordination bonds, leading to more robust composite HOFs, including ionic and metal types. The present study examines the fundamental design concepts and chemical synthons necessary for the development of HOFs, focussing on their structural variety from one-dimensional (1D) to three-dimensional (3D) designs. It provides a detailed exploration of HOFs properties, including luminescence, magnetism, mechanical strength, dielectric characteristics, guest exchange, adsorption, and electronic and optical features. The review also covers a range of synthesis methodologies, each offering unique benefits for tailoring HOFs structures and functionalities. The role of π-π interactions, structural integration, electrostatic interactions, and covalent bonding in enhancing structural integrity, resilience, and stability is highlighted in the detailed discussion of key strategies for increasing the stability of HOFs. Additionally, diverse functionalization strategies incorporating various chemical groups are explored for the first time, showing how they can modify and expand HOFs properties. Finally, the review addresses different HOFs morphologies, including thin films, nanosheets, nanospheres, and nanotubes, and their broad applications in fields such as batteries, membranes, sensors, separation technologies, supercapacitors, carbon dioxide capture, electrocatalysts, photocatalysts, proton conductivity, and biological applications. In this review, we aim to provide a comprehensive platform that covers all aspects of HOFs, especially highlighting a wide range of different functionality units and dimensionality. This detailed examination provides readers with an in-depth comprehension of the characteristics and possible uses of HOFs, setting our review distinct via its wide-ranging breadth and thorough analysis. This comprehensive overview illustrates the significant potential of HOFs to advance various technological and scientific domains.