We will highlight some of the new opportunities that solid-state nuclear magnetic resonance (SSNMR) spectroscopy brings to the investigations of catalytic systems. Firstly, we will describe the use of state-of-the-art ‘conventional’ SSNMR spectroscopy utilizing fast magic angle spinning (MAS), especially two-dimensional (2D) heteronuclear correlation (HETCOR) and J-resolved techniques. We use these methods to determine the structure of (1) a mesoporous silica nanoparticle (MSN)-supported zirconium amide complex, which proved to be a competent and recyclable catalyst for the reduction of carbonyls by catalytic hydroboration, and (2) a series of silica-grafted hydroamination catalysts that are prepared using b-SiH-containing rare earth complexes. We will secondly demonstrate the applications of dynamic nuclear polarization (DNP)-enhanced SSNMR methods. DNP can boost SSNMR’s sensitivity by 2-3 orders of magnitude, and is poised to significantly impact the studies of catalytic materials and reactions by enabling the detection of insensitive nuclei, minute concentrations of molecules and the examination of much smaller surfaces than previously possible. We will illustrate some of these new capabilities by presenting the studies of (3) metal organic frameworks, where the DNP-enhanced spectra of natural abundance 15N, 17O and 195Pt nuclei are used to elucidate the atomic-scale structure of metal ions and defects in MOFs, and (4) the molecular structure of lignocellulosic biomass, where the DNP-enhanced 2D homonuclear 13C-13C correlation SSNMR spectra, under natural abundance, yielded, for the first time, an atomic-level picture of the structure of raw and catalytically treated biomass samples.

Atomic-scale characterization of catalytic materials by advanced solid-state NMR methods

253rd National Meeting (2017)

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