Are Metal-Metal Interactions Involved in the Rising Enthalpies Observed in The Kubas Binding of H-2 to Hydrazine-Linked Hydrogen Storage Materials?

作者：Skipper Claire V J^*; Antonelli David M; Kaltsoyannis Nikolas

来源：Journal of Physical Chemistry C, 2012, 116(36): 19134-19144.

DOI：10.1021/jp3051643

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 H-2 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 H-2 molecules that can be bound, and replacing a hydrazide ligand with a hydride increases the M-H-2 interaction energy. Evidence is presented for metal-metal interactions, which can influence the H-2 binding enthalpy and may help to explain the observed metallic properties and rising H-2 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 H-2 ligand.

• 出版日期2012-9-13