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2 H Solid‐State NMR Spectroscopy Reveals the Dynamics of a Pyridine Probe Interacting with Coordinatively Unsaturated Metal Sites of MIL‐100(Al) Metal–Organic Frameworks
Author(s) -
Khudozhitkov Alexander E.,
Toktarev Alexander V.,
Arzumanov Sergei S.,
Gabrienko Anton A.,
Kolokolov Daniil I.,
Stepanov Alexander G.
Publication year - 2019
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201901956
Subject(s) - pyridine , chemistry , reagent , nuclear magnetic resonance spectroscopy , metal , metal organic framework , catalysis , spectroscopy , inorganic chemistry , photochemistry , adsorption , stereochemistry , organic chemistry , physics , quantum mechanics
Coordinatively unsaturated metal sites (CUS) play an important role in catalysis by metal‐organic frameworks (MOF). Being an intrinsic part of the framework the CUS take the role of acidic sites active in industrially relevant processes such as condensation or oxidation reactions. The key step of such reactions represents the coordination of the reagents to CUS. In MOFs the mechanism of the reagent interaction with CUS is poorly understood. Herein, we characterize the interaction of a widely used acidity probe pyridine with CUS of MIL‐100(Al) MOF by means of the 2 H solid‐state NMR spectroscopy. 2 H NMR reveals that pyridine species, which are interacting with CUS and the ones which are coordinated to the Al−OH site, exhibit different motional behavior. 2 H NMR line shape as well as T 1 , T 2 relaxation analyses for [D 5 ]pyridine adsorbed in MIL‐100(Al) allowed us to perform a detailed characterization of pyridine dynamics in both states including the kinetics of the exchange process between these adsorption states.