Are Metal鈥揗etal Interactions Involved in the Rising Enthalpies Observed in The Kubas Binding of H2 to Hydrazine-Linked Hydrogen Storage Materials?

详细信息    查看全文

• 作者：Claire V. J. Skipper ; David M. Antonelli ; Nikolas Kaltsoyannis
• 刊名：The Journal of Physical Chemistry C
• 出版年：2012
• 出版时间：September 13, 2012
• 年：2012
• 卷：116
• 期：36
• 页码：19134-19144
• 全文大小：419K
• 年卷期：v.116,no.36(September 13, 2012)
• ISSN：1932-7455

文摘

Models of two linked M(III) and M(II) (M = Ti, V, Cr) binding sites in hydrazine-linked hydrogen storage materials have been studied quantum chemically using density functional theory. The results compare favorably with previous experimental and computational results. Strong evidence is observed that the H₂ molecules bind to the metal in a Kubas manner. As seen previously in monometallic analogues,(1, 2) altering the transition metal across the first row of the periodic table reduces the number of H₂ molecules that can be bound, and replacing a hydrazide ligand with a hydride increases the M-H₂ interaction energy. Evidence is presented for metal鈥搈etal interactions, which can influence the H₂ binding enthalpy and may help to explain the observed metallic properties and rising H₂ binding enthalpies with coverage of the experimental materials. An alternate explanation for the rising enthalpies is also proposed, involving a pressure-induced deformation of the structure with concomitant twisting of the bonds into conformations that allow more optimal binding of an H₂ ligand.