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In Situ X‐ray Absorption Spectroscopy and Nonclassical Catalytic Hydrogenation with an Iron(II) Catecholate Immobilized on a Porous Organic Polymer
Author(s) -
Kraft Steven J.,
Hu Bo,
Zhang Guanghui,
Miller Jeffrey T.,
Hock Adam S.
Publication year - 2013
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201300528
Subject(s) - chemistry , x ray absorption spectroscopy , catalysis , oxidation state , absorption spectroscopy , absorption (acoustics) , olefin fiber , photochemistry , spectroscopy , inorganic chemistry , extended x ray absorption fine structure , hydrogen , chemical state , heterogeneous catalysis , x ray photoelectron spectroscopy , chemical engineering , organic chemistry , physics , quantum mechanics , acoustics , engineering
The oxidation state and coordination number of immobilized iron catecholate EtO 2 Fe(CAT‐POP) were determined by X‐ray absorption spectroscopy (XAS) under a variety of conditions. We find the as‐prepared material to be three‐coordinate Fe 2+ that readily oxidizes to Fe 3+ upon exposure to air but remains three‐coordinate. Both the reduced and oxidized Fe(CAT‐POP) catalyze olefin hydrogenation in batch and flow reactors. We determined the catalytic rates for both species and also observed by means of XAS that the oxidation state of the iron centers does not change in hydrogen at the reaction temperature. Therefore, we postulate that the mechanism of hydrogenation by Fe(CAT‐POP) proceeds through one of several possible nonclassical mechanisms, which are discussed.