Natural Abundance 17O DNP NMR Provides Precise O−H Distances and Insights into the Brønsted Acidity of Heterogeneous Catalysts
Wiley-VCH VerlagGmbH & Co. KGaA, Weinheim
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Heterogeneous Brønsted acid catalysts are tremendously important in industry, particularly in catalytic cracking processes. Here we show that these Brønsted acid sites can be directly observed at natural abundance by 17O DNP surface-enhanced NMR spectroscopy (SENS). We additionally show that the O−H bond length in these catalysts can be measured with sub-picometer precision, to enable a direct structural gauge of the lability of protons in a given material, which is correlated with the pH of the zero point of charge of the material. Experiments performed on materials impregnated with pyridine also allow for the direct detection of intermolecular hydrogen bonding interactions through the lengthening of O−H bonds.
This is the peer-reviewed version of the following article: Perras, Frédéric A., Zhuoran Wang, Pranjali Naik, Igor I. Slowing, and Marek Pruski. "Natural Abundance 17O DNP NMR Provides Precise O− H Distances and Insights into the Brønsted Acidity of Heterogeneous Catalysts." Angewandte Chemie International Edition 56, no. 31 (2017): 9165-9169, which has been published in final form at DOI: 10.1002/anie.201704032. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving. Copyright 2017 Wiley-VCH VerlagGmbH & Co. KGaA, Weinheim. Posted with permission.