Host-Guest Interactions Between Metal-Organic Frameworks and Air-Sensitive Complexes at High Temperature

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Engineering

Background:

• Host-guest chemistry in metal-organic frameworks (MOFs) offers unique properties but faces synthesis challenges with air-sensitive guests.
• Understanding high-temperature host-guest interactions in MOFs is crucial for advanced applications.
• Existing methods struggle with incorporating sensitive metal complexes into MOF structures.

Purpose of the Study:

• To develop a robust synthetic method for MOF host-guest systems incorporating air-sensitive metal complexes.
• To investigate the high-temperature behavior and interaction dynamics of guests within different MOF hosts.
• To compare the stability and loading capacities of Fe(CO)5 in HKUST-1 and NH2-MIL-101(Al) MOFs.

Main Methods:

• Chemical vapor infiltration (CVI) process for synthesizing MOF host-guest systems.
• Synchrotron X-ray powder diffraction (XRPD) for structural analysis.
• Fourier Transform Infrared Spectroscopy (FTIR) for chemical composition analysis.

Main Results:

• Successful loading of iron pentacarbonyl (Fe(CO)5) into HKUST-1 and NH2-MIL-101(Al) confirmed via XRPD and FTIR.
• HKUST-1 demonstrated strong interaction with Fe(CO)5, achieving high loading (63.1 wt%) but undergoing structural deformation at high temperatures.
• NH2-MIL-101(Al) exhibited weaker, chemically inert interactions with Fe(CO)5, indicating greater high-temperature stability.

Conclusions:

• The developed CVI method effectively synthesizes MOF host-guest systems with air-sensitive metal complexes.
• HKUST-1's strong interaction with Fe(CO)5 leads to high loading but compromises thermal stability.
• NH2-MIL-101(Al) offers a more stable platform for Fe(CO)5 at elevated temperatures due to weaker interactions.