Synthesis, Spectroscopy, and Hydrogen/Deuterium Exchange in High-Spin Iron(II) Hydride Complexes

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• 作者：Thomas R. Dugan ; Eckhard Bill ; K. Cory MacLeod ; William W. Brennessel ; Patrick L. Holland
• 刊名：Inorganic Chemistry
• 出版年：2014
• 出版时间：March 3, 2014
• 年：2014
• 卷：53
• 期：5
• 页码：2370-2380
• 全文大小：490K
• 年卷期：v.53,no.5(March 3, 2014)
• ISSN：1520-510X

文摘

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.