Low-Temperature N−O Bond Cleavage of Nitrogen Monoxide in Heterometallic Carbonyl Complexes. An Experimental and Theoretical Study
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- 作者：M. Esther Garcí ; a ; Sonia Meló ; n ; Miguel A. Ruiz ; Ramó ; n Ló ; pez ; Tomá ; s Sordo ; Luciano Marchiò ; Antonio Tiripicchio
- 刊名：Inorganic Chemistry
- 出版年：2008
- 出版时间：November 17, 2008
- 年：2008
- 卷：47
- 期：22
- 页码：10644-10655
- 全文大小：418K
- 年卷期：v.47,no.22(November 17, 2008)
- ISSN：1520-510X
文摘
The reaction of Na[RuCp(CO)2] with [MnCp′(CO)2(NO)]BF4 gives the corresponding heterometallic derivative [MnRuCpCp′(μ-CO)2(CO)(NO)] (Cp = η5-C5H5; Cp′ = η5-C5H4Me). In contrast, the group 6 metal carbonyl anions [MCp(CO)2L]− (M = Mo, W; L = CO, P(OMe)3, PPh3) react with the Mn and Re complexes [M′Cp′(CO)2(NO)]BF4 to give the heterometallic derivatives [MM′CpCp′(μ-N)(CO)3L] having a nitride ligand linearly bridging the metal centers (W−N = 1.81(3) Å, N−Re = 1.97(3) Å, W−N−Re = 179(1)o, in [WReCpCp′(μ-N)(CO)3{P(OMe)3}]). Density-functional theory calculations on the reactions of [WCp(CO)3]− and [RuCp(CO)2]− with [MnCp(CO)2(NO)]+ revealed a comparable qualitative behavior. Thus, two similar and thermodynamically allowed reaction pathways were found in each case, one implying the displacement of CO from the cation and formation of a metal−metal bond, the other implying the cleavage of the N−O bond of the nitrosyl ligand and release of a carbonyl from the anion as CO2. The second pathway is more exoergonic and is initiated through an orbitally controlled attack of the anion on the N atom of the NO ligand in the cation. In contrast, the first pathway is initiated through a charge-controlled attack of the anion to the C atom of a CO ligand in the cation. The CO2-elimination pathway requires at the intermediate stages a close approach of the NO and CO ligands, which is more difficult for the Ru compound because of its lower coordination number (compared to W). This effect, when combined with a stronger stabilization of the initial intermediate in the Ru reaction, makes the CO2-elimination pathway slower in that case.