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Natural Abundance 17 O DNP NMR Provides Precise O−H Distances and Insights into the Brønsted Acidity of Heterogeneous Catalysts
Author(s) -
Perras Frédéric A.,
Wang Zhuoran,
Naik Pranjali,
Slowing Igor I.,
Pruski Marek
Publication year - 2017
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201704032
Subject(s) - catalysis , lability , hydrogen bond , pyridine , abundance (ecology) , brønsted–lowry acid–base theory , intermolecular force , spectroscopy , chemistry , materials science , inorganic chemistry , physics , molecule , organic chemistry , quantum mechanics , fishery , biology
Abstract 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 17 O 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.