RMN de Surface Exalté par Polarisation Dynamique Nucléaire

Nuclear magnetic resonance (NMR) spectroscopy (often in conjunction with diffraction methods) is the method of choice for the molecular level characterization of materials (whether molecular, inorganic, nano-structured or biological), but many modern materials are below the sensitivity limit of detection for NMR. The sensitivity enhancement provided by DNP (factors up to several hundred) leads to reductions in experimental times of between three to five orders of magnitude. The performance of commercial DNP systems capable of providing these enhancements (mostly at 400 MHz) is outstanding, and already is the center of a plethora of new developments in NMR spectroscopy that were previously considered inconceivable. The project concerned the acquisition and the operation of one of the very first 800 MHz DNP accessories at the Institut des Sciences Analytiques (ISA) de Lyon. This instrument has been successfully installed in August 2013 (Tranche 1) and was the second 527 GHz system to be delivered in the world. While the first high field DNP NMR experiments have been focused on biological systems, we were particularly interested in the novel possibility that DNP yields to characterize surfaces and surface species central to modern sustainable chemistry, through catalysis and nanosciences. The introduction of new, more efficient polarizing agents (in 2013), the amplification of the DNP effect by the incorporation of solid dielectrics into frozen solutions (2014), the demonstration that high enhancement factors could be preserved at high temperature (2015), the publication of the first (worldwide) DNP spectra at fast magic angle spinning (in early 2016) and more recently of record enhancements of above 100 at 18.8 T (2017) and the development of radicals tailored for DNP at very high fields (2018) are some of the landmark achievements of the first seven years.