BARRIER TO ROTATION OF THE DIHYDROGEN LIGAND IN METAL-COMPLEXES
BARRIER TO ROTATION OF THE DIHYDROGEN LIGAND IN METAL-COMPLEXES
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DOI：
10.1021/j100112a044
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发表时间：
1993-03-11
影响因子：
--
通讯作者：
KUBAS, GJ
中科院分区：
文献类型：
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作者：
ECKERT, J;KUBAS, GJ
某些金属配合物将以分子形式结合氢的事实提供了一个机会，可以在固态下研究最简单的受阻分子旋转问题，即具有一个旋转自由度的双最小势的哑铃分子。这种新的配体的旋转障碍是来自非弹性中子散射测量其旋转跃迁和解释的各种类型的相互作用，引起它。这些包括二氢和金属之间的直接电子相互作用，电子效应（通过金属）的其他配体的金属，和空间位阻效应。这些研究的显著结果是，二氢的旋转势垒可以作为金属与其配体之间某些电子相互作用的非常灵敏的探针。它也作为电子计算的主要定量基准，旨在达到对二氢金属结合的理解。本文将联合收割机的几个新结果与我们以前的工作结合起来，系统地讨论了势垒高度随金属中心的类型、共配体和抗衡离子的性质以及它们对金属-二氢结合和H-H键活化的影响。
The fact that certain metal complexes will bind hydrogen in molecular form has provided an opportunity to examine in the solid state the simplest hindered molecular rotation problem, namely, that of a dumbbell molecule in a double-minimum potential with one rotational degree of freedom. The barrier to rotation of this novel ligand is derived from inelastic neutron scattering measurements of its rotational transitions and interpreted in terms of the various types of interactions that give rise to it. These include the direct electronic interaction between dihydrogen and the metal, electronic effects (via the metal) of the other ligands on the metal, and steric effects. The remarkable result of these studies is that the barrier to rotation of dihydrogen serves as a very sensitive probe of some of the electronic interactions between the metal and its ligands. It also serves as the principal quantiative benchmark for electronic calculations aimed at arriving at an understanding of dihydrogen metal binding. In this paper we combine several new barrier height results with those from our previous work to discuss systematics of the variation of barrier height with the type of metal center, the nature of the coligands and counterions as well as their implications for metal-dihydrogen binding, and H-H bond activation.