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Heterolytic Cleavage of Hydrogen by an Iron Hydrogenase Model: An Fe‐H⋅⋅⋅H‐N Dihydrogen Bond Characterized by Neutron Diffraction
Author(s) -
Liu Tianbiao,
Wang Xiaoping,
Hoffmann Christina,
DuBois Daniel L.,
Bullock R. Morris
Publication year - 2014
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201402090
Subject(s) - heterolysis , chemistry , hydrogenase , neutron diffraction , crystallography , cleavage (geology) , bond cleavage , hydrogen , hydrogen bond , ligand (biochemistry) , crystal structure , stereochemistry , catalysis , molecule , materials science , organic chemistry , biochemistry , receptor , composite material , fracture (geology)
Hydrogenase enzymes in nature use hydrogen as a fuel, but the heterolytic cleavage of HH bonds cannot be readily observed in enzymes. Here we show that an iron complex with pendant amines in the diphosphine ligand cleaves hydrogen heterolytically. The product has a strong Fe‐H⋅⋅⋅H‐N dihydrogen bond. The structure was determined by single‐crystal neutron diffraction, and has a remarkably short H⋅⋅⋅H distance of 1.489(10) Å between the protic N‐H δ+ and hydridic Fe‐H δ− part. The structural data for [Cp C 5 F 4 N Fe H (P t Bu 2 N t Bu 2 H )] + provide a glimpse of how the HH bond is oxidized or generated in hydrogenase enzymes. These results now provide a full picture for the first time, illustrating structures and reactivity of the dihydrogen complex and the product of the heterolytic cleavage of H 2 in a functional model of the active site of the [FeFe] hydrogenase enzyme.