Smart Hydrogen-Bonded Organic Frameworks: From Design Rules to Applications.

Area of Science:

• Materials Science
• Supramolecular Chemistry
• Nanotechnology

Background:

• Metal-organic frameworks (MOFs) and covalent organic frameworks (COFs) are crystalline porous materials.
• Hydrogen-bonded organic frameworks (HOFs) represent a paradigm shift with adaptive porosity.
• HOFs utilize weak, reversible hydrogen interactions, leading to intrinsic framework flexibility.

Purpose of the Study:

• To systematically discuss the design principles of smart HOFs.
• To highlight the translation of HOF flexibility into advanced functionalities.
• To provide an outlook on future challenges and practical deployment of HOFs.

Main Methods:

• Review and synthesis of existing research on HOF design and applications.
• Analysis of flexibility mechanisms in HOFs and their impact on functionality.
• Exploration of HOF applications in separations, sensing, optoelectronics, and biomedicine.

Main Results:

• HOFs exhibit reversible transformations like breathing, gate-opening, and layer sliding.
• Adaptive pore environments in HOFs enable molecular discrimination and self-healing in separations.
• HOFs facilitate precise sensing through stimuli-induced signal transduction (optical/electrical).
• Dynamic luminescence and topological switching in HOFs are leveraged for optoelectronics and information security.
• Stimuli-responsive drug release and biocompatibility are explored for HOF-based biomedical therapies.

Conclusions:

• Smart HOFs offer unique adaptive properties for diverse applications.
• Challenges remain in HOF stability, predictability, and processability for practical use.
• Further research is needed to bridge the gap between HOF design and real-world deployment.