Intramolecular Nitrene Transfer via the C≡N Bond Cleavage of Acetonitrile to a μ3-Alkylidyne Ligand on a Cationic Triruthenium Plane
Intramolecular Nitrene Transfer via the C≡N Bond Cleavage of Acetonitrile to a μ3-Alkylidyne Ligand on a Cationic Triruthenium Plane
复制标题
通过乙腈的 CeqN 键断裂将分子内氮烯转移到阳离子三钌平面上的 μ3-烷基配体
DOI：
10.1021/acs.organomet.0c00393
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发表时间：
2020
期刊：
影响因子：
2.8
通讯作者：
Takao Toshiro
中科院分区：
文献类型：
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作者：
Takahashi Yusuke;Tahara Atsushi;Takao Toshiro
μ3-η - 2-亚氨基酰-μ3-己基炔配合物[(Cp*Ru)3(μ3- cc5h11)(μ3-η - hn = CMe)(μ-H)] （2a) (Cp* = η5-C5Me5)）是由μ3-η2:η2(⊥)-己基炔配合物[{Cp*Ru(μ-H)}3(μ3-η2:η2- nbucch)] （1a）与乙腈反应制备的。2的质子化反应生成了阳离子μ3-η - 2-亚氨基酰基络合物[(Cp*Ru)3(μ3- η - hn = CMe)(μ-H)2]+(3a3b)的平衡混合物，它们是相对于桥接氢化物的位置异构体。μ3-η - 2-亚氨基酰基配体in2a在核磁共振时间尺度上是刚性的，而in3bit则表现出迁移性，这是由于阳离子Ru3core的反给价减少。与robust2a相反，由于μ3-η - 2-亚氨基酰基配体的迁移性，3b在热裂解时发生了骨架重排。在140℃下，通过亚氨基酰基配体向μ3-己炔碳的分子内亚硝基转移，3a3b的平衡混合物转化为μ3-乙基炔-μ3-η - 2-1-亚氨基己基络合物[(Cp*Ru)3(μ3- cch3)(μ3-η - hn = CC5H11)(μ-H)2]+(4a4b)。密度泛函理论（DFT）计算表明，与μ3-己基炔配体in3a，b相比，μ3-己基炔配体in4a导致与周围Cp*基团的空间排斥力降低。μ3-乙炔配体的形成所产生的稳定化作用可能是这种转变的驱动力。
The μ3-η2-iminoacyl-μ3-hexylidyne complex, [(Cp*Ru)3(μ3-CC5H11)(μ3-η2-HN═CMe)(μ-H)] (2a) (Cp* = η5-C5Me5), was prepared by the reaction of the μ3-η2:η2(⊥)-hexyne complex, [{Cp*Ru(μ-H)}3(μ3-η2:η2-nBuCCH)] (1a), with acetonitrile. Protonation of2ayielded an equilibrated mixture of cationic μ3-η2-iminoacyl complexes, [(Cp*Ru)3(μ3-CC5H11)(μ3-η2-HN═CMe)(μ-H)2]+(3aand3b), which are positional isomers with respect to the bridging hydrides. While the μ3-η2-iminoacyl ligand in2awas rigid at the NMR time-scale, in3bit exhibited mobility, owing to the reduced back-donation from the cationic Ru3core. In contrast to robust2a,3bunderwent skeletal rearrangement upon thermolysis because of the mobility of the μ3-η2-iminoacyl ligand. The equilibrated mixture of3aand3bwas transformed into an equilibrated mixture of μ3-ethylidyne-μ3-η2-1-iminohexyl complexes, [(Cp*Ru)3(μ3-CCH3)(μ3-η2-HN═CC5H11)(μ-H)2]+(4aand4b) at 140 °C, via the intramolecular nitrene transfer from the iminoacyl ligand to the μ3-hexylidyne carbon. Density functional theory (DFT) calculations suggest that the μ3-ethylidyne ligand in4a,bleads to decreased steric repulsion with the surrounding Cp* groups, as compared with the μ3-hexylidyne ligand in3a,b. The stabilization arising from the formation of the μ3-ethylidyne ligand is a possible driving force for the transformation.