Low valent transition metal clusters containing nitrene/imido ligands
Low valent transition metal clusters containing nitrene/imido ligands
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DOI：
10.1016/s0010-8545(03)00082-1
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发表时间：
2003-08
影响因子：
20.6
通讯作者：
Yat Li;W. Wong
中科院分区：
文献类型：
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作者：
Yat Li;W. Wong
本文综述了含氮烯/亚氨基配体的低价过渡金属簇合物的合成、结构、光谱性质和反应活性研究。这些氮烯/亚胺封端的过渡金属簇合物（均金属和杂金属）的合成路线进行了概括。近几十年来，X射线晶体学已经建立了这些物种的许多结构。描述了它们的几何特征，这些几何特征受封端配体和金属原子的控制，并着重介绍了这些含（μ 3-或μ 4-NH）氮烯配体的簇合物的~1H-和~（15）N-NMR研究。在μ 4-NH和μ 3-NH成键模式下，氮原子与金属的相互作用程度不同，导致了不同的NMR参数。讨论了配位体和金属原子对NH质子信号的影响。这些簇的电化学响应与封端配体的性质直接相关，并且簇价电子（CVE）的添加/还原导致簇几何结构的显著变化。μ 3-亚氨基封端的三钌金属簇合物是硝基化合物还原羰基化反应中的活性中间体。提出的催化机理进行了讨论。
This short review describes the synthesis, structural and spectroscopic properties, and reactivity studies of low valent transition metal clusters that contain nitrene/imido ligands. The synthetic routes to these nitrene/imido-capped transition metal clusters (both homometallic and heterometallic) are generalized. Numerous structures of these species have been established by X-ray crystallography in recent decades. Their geometric features, which are governed by the capping ligands and metal atoms, are described, and the1H- and15N-NMR studies of these clusters with (μ3- or μ4-NH) nitrene ligands are highlighted. The different degrees of interaction of nitrogen atoms with metals in μ4-NH and μ3-NH bonding modes result in distinct NMR parameters. The influences of the coordinated ligands and metal atoms on the NH proton signal are also discussed. The electrochemical responses of these clusters are directly related to the nature of the capping ligands, and the addition/reduction of cluster valence electron (CVE) leads to marked changes in the cluster geometry. The μ3-imido capped triruthenium metal clusters are known to be the active intermediates in the reductive carbonylation of nitro-compounds. The proposed catalytic mechanisms are discussed.