Intramolecular Rearrangements in Six-Coordinate Ruthenium and Iron Dihydrides
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- 作者：Chirine Soubra ; Yasuo Oishi ; Thomas A. Albright ; and Hiroshi Fujimoto
- 刊名：Inorganic Chemistry
- 出版年：2001
- 出版时间：February 12, 2001
- 年：2001
- 卷：40
- 期：4
- 页码：620 - 627
- 全文大小：119K
- 年卷期：v.40,no.4(February 12, 2001)
- ISSN：1520-510X
文摘
Molecular orbital calculations at the ab initio level are used to study polytopal rearrangements in H2Ru(PH3)4 andH2Fe(CO)4 as models of 18-electron, octahedral metal dihydrides. It is found that, in both cases, the transitionstate for these rearrangements is a dihydrogen species. For H2Fe(CO)4, this is a square pyramidal complex wherethe H2 ligand occupies an apical position and is rotated by 45
from its original orientation. This is preciselyanalogous to the transition state for Fe-olefin rotation in (olefin)Fe(CO)4 complexes and has a very similarelectronic origin. Another transition state very close in energy is found wherein the basic coordination geometryis a trigonal bipyramid and the H2 ligand is coordinated in the axial position. For H2Ru(PH3)4, the former stationarypoint lies at a much higher energy and the latter clearly serves as the transition state for hydride exchange. Thereason for this difference is discussed along with the roles of electron correlation in the two compounds.
from its original orientation. This is preciselyanalogous to the transition state for Fe-olefin rotation in (olefin)Fe(CO)4 complexes and has a very similarelectronic origin. Another transition state very close in energy is found wherein the basic coordination geometryis a trigonal bipyramid and the H2 ligand is coordinated in the axial position. For H2Ru(PH3)4, the former stationarypoint lies at a much higher energy and the latter clearly serves as the transition state for hydride exchange. Thereason for this difference is discussed along with the roles of electron correlation in the two compounds.