title: Synthesis, spectroscopy, and hydrogen/deuterium exchange in high-spin iron(II) hydride complexes.
abstract: Very few hydride complexes are known in which the metals have a high-spin electronic configuration. We describe the characterization of several high-spin iron(II) hydride/deuteride isotopologues and their exchange reactions with one another and with H2/D2. Though the hydride/deuteride signal is not observable in NMR spectra, the choice of isotope has an influence on the chemical shifts of distant protons in the dimers through the paramagnetic isotope effect on chemical shift. This provides the first way to monitor the exchange of H and D in the bridging positions of these hydride complexes. The rate of exchange depends on the size of the supporting ligand, and this is consistent with the idea that H2/D2 exchange into the hydrides occurs through the dimeric complexes rather than through a transient monomer. The understanding of H/D exchange mechanisms in these high-spin iron hydride complexes may be relevant to postulated nitrogenase mechanisms.
authors.affiliation: Department of Chemistry, University of Rochester , Rochester, New York 14627, United States.
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Dugan
authors.forename: Eckhard
authors.initials: E
authors.lastname: Bill
authors.forename: K Cory
authors.initials: KC
authors.lastname: MacLeod
authors.forename: William W
authors.initials: WW
authors.lastname: Brennessel
authors.forename: Patrick L
authors.initials: PL
authors.lastname: Holland
mesh_terms: D056831:Coordination Complexes / Q000138:chemical synthesis / Q000737:chemistry*; D018360:Crystallography, X-Ray; D003903:Deuterium / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D013057:Spectrum Analysis
chemical_list: D056831:Coordination Complexes; D006859:Hydrogen; D003903:Deuterium; D007501:Iron