Radical-Driven Crystal-Amorphous-Crystal Transition of a Metal-Organic Framework

Area of Science:

• Materials Science
• Chemistry
• Nanotechnology

Background:

• Self-assembly is crucial for developing functional materials like molecular machines and sensors.
• Metal-organic frameworks (MOFs) offer tunable structures but often lack dynamic flexibility.
• Controlling structural transitions in MOFs is key to unlocking new applications.

Purpose of the Study:

• To design and synthesize novel redox-active metal-organic frameworks (MOFs) with enhanced structural transition capabilities.
• To investigate the mechanism of ligand self-assembly-driven structural transitions in these new MOFs.
• To explore the role of radical formation in inducing reversible structural changes within MOFs.

Main Methods:

• Synthesis of new redox-active MOFs (DGIST-10 series) using π-acidic 1,4,5,8-naphthalenediimide (NDI)-based ligands and Ni²⁺ ions.
• Induction of radical formation during MOF synthesis and post-synthetic characterization.
• Observation and analysis of single-crystal-to-amorphous-to-single-crystal structural transitions using various techniques.

Main Results:

• Successful development of DGIST-10 series MOFs exhibiting redox activity.
• Observation of a unique single-crystal-amorphous-single-crystal structural transition triggered by radical formation.
• Confirmation of transient amorphous phase formation without morphological disintegration, enabling significant structural changes.

Conclusions:

• Ligand self-assembly and radical formation can induce unprecedented structural transitions in MOFs.
• The observed structural transitions significantly enhance the flexibility and diversity of MOF structures.
• This work provides a new pathway for designing dynamic MOFs with tunable properties for advanced applications.