Nanoparticle-assisted dynamic nuclear polarization in liquids.

Area of Science:

• Nanotechnology
• Chemical Physics
• Analytical Chemistry

Background:

• Gold nanoparticles (AuNPs) with self-assembled monolayers are useful in catalysis and sensing.
• AuNPs can serve as magnetization reservoirs for selective NMR signal transfer.
• Existing NMR chemosensing relies on nucleus-nucleus interactions.

Purpose of the Study:

• To investigate electron-nucleus interactions for enhanced Overhauser effect dynamic nuclear polarization (OE-DNP).
• To design AuNPs for selective molecular recognition and polarization transfer.
• To assess the feasibility of AuNPs as polarizing agents in NMR.

Main Methods:

• Functionalizing AuNPs with a radical-bearing thiol and a recognition-tailored thiol.
• Performing OE-DNP experiments on a chloroform and methanol mixture.
• Evaluating polarization transfer efficiency and selectivity.

Main Results:

• Significant signal enhancements observed for chloroform, potentially limited by radical mobility.
• Methanol affinity did not correlate with enhanced signals.
• AuNPs demonstrated effectiveness as polarizing agents up to 9.4 T magnetic fields.

Conclusions:

• AuNPs can act as polarizing agents for OE-DNP at high magnetic fields.
• Future monolayer modifications could combine polarization efficiency with molecular recognition.
• This approach offers a novel strategy for hyperpolarization and NMR detection.