Surface Enhanced Nuclear Magnetic Resonance Spectroscopy at Solid–Liquid Interfaces Using Overhauser Dynamic Nuclear Polarization

While solid–liquid interfaces are ubiquitous, detecting the associated surface sites under ambient conditions remains a grand challenge. Here, we demonstrate an approach to efficiently enhance the NMR signals of solid surfaces at the solid–liquid interface at ambient temperature that is based on exchange mediated Overhauser effect dynamic nuclear polarization (OE-DNP). We use this approach to obtain DNP enhancements for the 31 P signals of PPh 3 ligands interacting with Rh(I) surface sites, in prototypical silica-supported materials prepared via surface organometallic chemistry. Efficient enhancement (ε i ) is obtained under ambient conditions simultaneously at the surface (ε surface = 20–30) and in solution (ε solution up to 50), enabling detection of species both at the surface and in solution, opening the possibility to monitor surface and interfacial chemistry.