This research was supported as part of the Center for Molecular Electrocatalysis, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences. Pacific Northwest National Laboratory is operated by Battelle for the U.S. Department of Energy. We thank Dr. Molly O’Hagan for assistance with HSQC NMR experiments and Dr. John A. S. Roberts for assistance with the electrochemical studies. Research conducted at ORNL’s Spallation Neutron Source was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. Department of Energy. ORNL is managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract No. DE-AC05-00OR22725.
Heterolytic Cleavage of Hydrogen by an Iron Hydrogenase Model: An Fe-H⋅⋅⋅H-N Dihydrogen Bond Characterized by Neutron Diffraction†
Article first published online: 22 APR 2014
© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Angewandte Chemie International Edition
Volume 53, Issue 21, pages 5300–5304, May 19, 2014
How to Cite
Liu, T., Wang, X., Hoffmann, C., DuBois, D. L. and Bullock, R. M. (2014), Heterolytic Cleavage of Hydrogen by an Iron Hydrogenase Model: An Fe-H⋅⋅⋅H-N Dihydrogen Bond Characterized by Neutron Diffraction. Angew. Chem. Int. Ed., 53: 5300–5304. doi: 10.1002/anie.201402090
- Issue published online: 14 MAY 2014
- Article first published online: 22 APR 2014
- Manuscript Received: 4 FEB 2014
- U.S. Department of Energy
- U.S. Department of Energy. Grant Number: DE-AC05-00OR22725
- enzyme models;
- neutron diffraction
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-Hδ+ and hydridic Fe-Hδ− part. The structural data for [CpFeH(PtBu2NtBu2H)]+ 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 H2 in a functional model of the active site of the [FeFe] hydrogenase enzyme.