Coordination Driven Capture of Nicotine Inside a Mesoporous MOF.

Area of Science:

• Materials Science
• Chemistry
• Nanotechnology

Background:

• Metal-organic frameworks (MOFs) are versatile porous polymers with applications in catalysis and gas storage.
• MOFs are increasingly investigated for encapsulating molecules and as potential drug delivery systems.

Purpose of the Study:

• To investigate the nicotine trapping capabilities of two related mesoporous copper-based MOFs, PCN-6 and PCN-6'.

Main Methods:

• Loading process monitored using electron ionization mass spectrometry (DIP-EI/MS), infrared (IR), and ultraviolet/visible (UV/VIS) spectroscopy.
• Nicotine uptake quantified via nuclear magnetic resonance (NMR) spectroscopy and thermogravimetric (TGA) analysis.
• Structural analysis of the MOF-nicotine complex using X-ray diffraction.

Main Results:

• Remarkable nicotine uptakes reaching up to 40 wt % were achieved in both PCN-6 and PCN-6' MOFs.
• X-ray structural analysis of PCN-6@nicotine demonstrated that nicotine loading is initiated by the pyridine ring coordinating to the copper nuclei within the framework's paddle-wheel units.

Conclusions:

• Mesoporous copper-based MOFs, specifically PCN-6 and PCN-6', show significant potential for nicotine encapsulation.
• The coordination interaction between nicotine's pyridine ring and the MOF's copper centers is crucial for effective guest uptake.