A Flexible Metal-Organic Framework with 4-Connected Zr₆ Nodes

Area of Science:

• Materials Science
• Chemistry
• Nanotechnology

Background:

• Zirconium-based metal-organic frameworks (Zr-MOFs) are recognized for their robust stability.
• Achieving flexibility in Zr-MOFs is difficult due to the high connectivity of their Zr6 nodes.

Purpose of the Study:

• To design and synthesize a flexible Zr-MOF with tunable structural properties.
• To investigate the guest-dependent structural flexibility and its impact on chemical reactivity.

Main Methods:

• Synthesis of a novel flexible Zr-MOF, NU-1400, utilizing 4-connected Zr6 nodes and tetratopic linkers.
• Single-crystal X-ray diffraction to analyze structural changes.
• Evaluation of reactivity towards a nerve agent simulant.

Main Results:

• NU-1400 exhibits significant guest-dependent structural flexibility, with unit cell volume contractions up to 48%.
• The expanded and contracted forms of NU-1400 display distinct reactivity profiles.
• Size-selective effects in different conformations influence reactant accessibility and reaction rates.

Conclusions:

• The development of NU-1400 demonstrates a successful strategy for introducing flexibility into Zr-MOFs.
• The observed structural flexibility and size-selectivity offer potential for tailored applications in catalysis and sensing.
• This work opens new avenues for designing responsive and adaptable metal-organic framework materials.