Synthesis and characterization of three-coordinate Ni(III)-imide complexes.
Synthesis and characterization of three-coordinate Ni(III)-imide complexes.
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DOI：
10.1021/ja2024993
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发表时间：
2011-08-24
影响因子：
15
通讯作者：
Hillhouse, Gregory L.
中科院分区：
文献类型：
--
作者：
Iluc, Vlad M.;Miller, Alexander J. M.;Anderson, John S.;Monreal, Marisa J.;Mehn, Mark P.;Hillhouse, Gregory L.
合成了以1，2-二(二叔丁基膦)乙烷为载体的新型低配位镍酰亚胺化合物。镍(II)络合物的氧化导致了芳基和烷基取代的镍(III)亚胺的形成，这两种类型的例子都已被分离和充分表征。证明对稳定Ni(III)-亚胺部分最有用的芳基取代基是体积较大的2，6-二甲基苯基。两种镍(III)-酰亚胺化合物具有不同的变温磁性，但在低温下具有相似的EPR谱。为了解释这一差异，提出了烷基取代亚胺镍(III)络合物的低自旋/高自旋平衡。这一建议得到了DFT计算的支持。密度泛函理论计算还表明，对于镍(III)络合物，未成对电子主要集中在亚胺氮上。在氢给体存在下进行的反应结果支持DFT计算的结果，即金刚烷基取代基是一个明显更活跃的氢原子抽取器。有趣的是，2，6-二甲基苯基取代基的空间性质不仅在保护Ni=N核方面很重要，而且通过将苯环锁定在相对于NiPP平面垂直的方向上，还有利于生成的镍(III)酰亚胺的一个旋转体。
A new family of low-coordinate nickel imides supported by 1,2-bis(di-tert-butylphosphino)ethane was synthesized. The oxidation of nickel(II) complexes led to the formation of both aryl- and alkyl-substituted nickel(III) imides, and examples of both types have been isolated and fully characterized. The aryl substituent that proved most useful in stabilizing the Ni(III)-imide moiety was the bulky 2,6-dimesitylphenyl. The two nickel(III)-imide compounds showed different variable-temperature magnetic properties, but analogous EPR spectra at low temperatures. In order to account for this discrepancy, a low-spin/high-spin equilibrium was proposed to take place for the alkyl-substituted imide nickel(III) complex. This proposal was supported by DFT calculations. DFT calculations also indicated that the unpaired electron is mostly localized on the imide nitrogen for the nickel(III) complexes. The results of reactions carried out in the presence of hydrogen donors supported the findings from DFT calculations that the adamantyl substituent was a significantly more reactive hydrogen-atom abstractor. Interestingly, the steric properties of the 2,6-dimesitylphenyl substituent are important not only in protecting the Ni=N core but also in favoring one rotamer of the resulting nickel(III) imide, by locking in the phenyl ring in a perpendicular orientation with respect to the NiPP plane.
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影响因子：
2.8
作者：
Bach, I;Porschke, KR;Seevogel, K
通讯作者：
Seevogel, K
影响因子：
4.9
作者：
Iluc, VM;Miller, AJM;Hillhouse, GL
通讯作者：
Hillhouse, GL
影响因子：
2.8
作者：
Curley, John J.;Kitiachvili, Kristina D.;Hillhouse, Gregory L.
通讯作者：
Hillhouse, Gregory L.
影响因子：
2.8
作者：
Guillemot, G;Solari, E;Rizzoli, C
通讯作者：
Rizzoli, C
DOI：
10.1002/anie.199606531
发表时间：
1996-04-01
期刊：
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION IN ENGLISH
影响因子：
--
作者：
Hanna, TA;Baranger, AM;Bergman, RG
通讯作者：
Bergman, RG