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Title: Vibrational characterization of a diiron bridging hydride complex – a model for hydrogen catalysis

Journal Article · · Chemical Science
DOI:https://doi.org/10.1039/d0sc01290d· OSTI ID:1816881

A diiron complex containing a bridging hydride and a protonated terminal thiolate of the form [(m,k2- bdtH)(m-PPh2)(m-H)Fe2(CO)5]+ has been investigated through 57Fe nuclear resonance vibrational spectroscopy (NRVS) and interpreted using density functional theory (DFT) calculations. We report the Fe–mH–Fe wagging mode, and indications for Fe–mD stretching vibrations in the D-isotopologue, observed by 57Fe-NRVS. Our combined approach demonstrates an asymmetric sharing of the hydride between the two iron sites that yields two nondegenerate Fe–mH/D stretching vibrations. The studied complex provides an important model relevant to biological hydrogen catalysis intermediates. The complex mimics proposals for the binuclear metal sites in [FeFe] and [NiFe] hydrogenases. It is also an appealing prototype for the ‘Janus intermediate’ of nitrogenase, which has been proposed to contain two bridging Fe–H–Fe hydrides and two protonated sulfurs at the FeMo-cofactor. The significance of observing indirect effects of the bridging hydride, as well as obstacles in its direct observation, is discussed in the context of biological hydrogen intermediates.

Research Organization:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). National Energy Research Scientific Computing Center (NERSC)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities Division; National Science Foundation (NSF); Einstein Foundation Berlin; German Research Foundation (DFG); Ministry of Science and Technology of Taiwan and Academia Sinica
Grant/Contract Number:
AC02-05CH11231; GM-65440; CHE 1308384; EVF-2016-277; EXC 2008-390540038; AS-SS-108-02-1
OSTI ID:
1816881
Journal Information:
Chemical Science, Vol. 11, Issue 21; ISSN 2041-6520
Publisher:
Royal Society of ChemistryCopyright Statement
Country of Publication:
United States
Language:
English

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