Stabilization of 3d Transition Metal Hydrido Complexes in SrH2Mg2[Co(I)H5], BaH2Mg5[Co(−I)H4]2, and RbH2Mg5[Co(−I)H4 Ni(0)H4] via Easily Polarizable Hydride Ligands

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• 作者：Henrik Fahlquist ; David Moser ; Dag Noréus ; Keith Refson ; Stewart F. Parker
• 刊名：Inorganic Chemistry
• 出版年：2016
• 出版时间：April 4, 2016
• 年：2016
• 卷：55
• 期：7
• 页码：3576-3582
• 全文大小：439K
• ISSN：1520-510X

文摘

A combined study using neutron diffraction, inelastic neutron scattering, and first-principles calculations describe cobalt with a very low formal oxidation state of (−I) in a slightly distorted tetrahedral Co(−I)H₄-complex in BaH₂Mg₅[Co(−I)H₄]₂ and in the structurally related RbH₂Mg₅[Co(−I)H₄ Ni(0)H₄]. This indicates that the electron “back donating” effect via the polarizable hydride ions to the counterions in the solid state hydrides, can be compared to more conventional “back bonding” able to reduce the oxidation state down to −I. The hydrides were synthesized by hot sintering of transition metal powders with corresponding binary alkali- and alkaline earth hydrides. In the similarly synthesized SrH₂Mg₂[Co(I)H₅], cobalt is formally + I-valent, showing a high sensitivity to differences in the counterion framework, which can also influence electrical properties.