Reduction of transition-metal-coordinated carbon monoxide by a rare-earth hydride cluster: isolation of well-defined heteromultimetallic oxycarbene, oxymethyl, carbene, and methyl complexes.
Reduction of transition-metal-coordinated carbon monoxide by a rare-earth hydride cluster: isolation of well-defined heteromultimetallic oxycarbene, oxymethyl, carbene, and methyl complexes.
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DOI：
10.1002/anie.200903660
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发表时间：
2009-10
影响因子：
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通讯作者：
Yasumasa Takenaka;T. Shima;J. Baldamus;Z. Hou
中科院分区：
文献类型：
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作者：
Yasumasa Takenaka;T. Shima;J. Baldamus;Z. Hou
通过金属氢化物还原过渡金属羰基配合物中的配位一氧化碳 (CO) [1-3] 至关重要，不仅对于费托合成 [4] 的机械方面至关重要，费托合成涉及在过渡金属催化剂存在下对 CO 进行氢化，而且还因为其在开发用于选择性形成碳氢化合物和含氧化合物的均相催化系统方面的潜在应用。迄今为止，人们已经对主族金属氢化物试剂（例如LiAlH4和NaBH4）或过渡金属氢化物络合物，例如[Cp* 2ZrHX](Cp*= C5Me5; X= H，卤化物）对配位CO的氢化进行了广泛的研究。[2, 3] 各种产物（或中间体）的形成，例如甲酰基（MÀ CHO）、氧卡宾（M=已观察到烯二醇酯 (MOCH= CHOM)、羟甲基 (MCH2OM) 和甲基 (MÀMe 或 MCH2-M) 物质，但仅对有限数量的这些化合物进行了结构表征。相比之下，稀土（第3族和镧系）金属氢化物对配位CO的还原几乎没有研究。唯一的先例是钪碳烯氢化物络合物[Cp* 2ScH (thf)]与[CpCo (CO) 2](Cp= C5H5)反应，产生钪碳烯物种[CpCo (-CO) C (H) OScCp* 2]。[3f]我们最近发现带有环戊二烯基配体的稀土金属多氢化物络合物，例如[{Cp’Y-(μ-H) 2} 4 (thf)](1; Cp’= η5-C5Me4SiMe3) 对各种不饱和底物（包括气态 CO 和 CO2）可以表现出独特的反应活性。[5–7] 在此，我们报道了氢化钇簇 1 与第 6、7 和 9 族金属配合物中配位 CO 配体的反应，提供了一系列结构明确的新化合物杂金属氧卡宾、氧甲基、卡宾氧代和甲基氧代配合物。反应模式取决于过渡金属羰基络合物的性质。还描述了这些反应的机理。
The reduction of coordinated carbon monoxide (CO) in transition-metal carbonyl complexes by metal hydrides [1–3] is of critical importance, not only for mechanistic aspects of the Fischer–Tropsch synthesis,[4] which involves the hydrogenation of CO in the presence of transition-metal catalysts, but also because of its potential applications in the development of homogeneous catalytic systems for the selective formation of hydrocarbons and oxygenates. To date, extensive studies have been carried out on the hydrogenation of coordinated CO by main-group-metal hydride reagents (eg, LiAlH4 and NaBH4) or transition-metal hydride complexes, for example [Cp* 2ZrHX](Cp*= C5Me5; X= H, halide).[2, 3] The formation of various products (or intermediates) such as formyl (MÀ CHO), oxycarbene (M= CHOM), enediolate (MOCH= CHOM), oxymethyl (MCH2OM), and methyl (MÀMe or MCH2-M) species has been observed, but only a limited number of these compounds has been structurally characterized. In contrast, the reduction of coordinated CO by rare-earth (Group 3 and lanthanide) metal hydrides has hardly been studied. The only precedent was the reaction of scandocene hydride complex [Cp* 2ScH (thf)] with [CpCo (CO) 2](Cp= C5H5), which yielded the scandoxycarbene species [CpCo (-CO) C (H) OScCp* 2].[3f]We recently found that rare-earth-metal polyhydride complexes bearing cyclopentadienyl ligands such as [{Cp’Y-(μ-H) 2} 4 (thf)](1; Cp’= η5-C5Me4SiMe3) can show unique reactivity toward various unsaturated substrates, including gaseous CO and CO2.[5–7] Herein, we report the reactions of the yttrium hydride cluster 1 with coordinated CO ligands in Group 6, 7, and 9 metal complexes, which afforded a new series of structurally well-defined heterometallic oxycarbene, oxymethyl, carbene oxo, and methyl oxo complexes. The reaction pattern depends on the nature of the transition-metal carbonyl complexes. Mechanistic aspects of these reactions are also described.