74685-83-9Relevant articles and documents
Cyclic (Amino)(Aryl)Nitrenium Cations with Lewis Acidity Controlled by Remote Substituents
Li, Shunjie,Wang, Wenqing,Wang, Xinping,Zhang, Leran,Zhao, Yue,Zheng, Xin
supporting information, p. 311 - 316 (2021/12/24)
N-Heterocyclic nitrogen Lewis acids are important in synthetic chemistry. Stable cyclic (amino)(aryl)nitrenium cations, cyc-1+—cyc-3+, were synthesized by chemical oxidation of aryl azo compounds with different substituents, iPr, H and I, at the para positions of the phenyl group. The excited triplet states of cyc-1+—cyc-3+ abstract H-atoms step by step to generate radical intermediates cyc-1H?+—cyc-3H?+ traced by EPR spectroscopy and products cyc-1H2+—cyc-3H2+ characterized by single crystal X-ray diffraction. The Lewis acidity of species cyc-1+—cyc-3+ are remote substituent-dependent. Cyc-2+—cyc-3+ have much higher acidity than those previously reported congeners based on energies of LUMOs. The electrophilicity enables them to form Lewis adducts with neutral Lewis base Me3P, and to gain one-electron to produce neutral radicals cyc-1?—cyc-3?.
Protonolysis and Amide Exchange Reactions of a Three-Coordinate Cobalt Amide Complex Supported by an N-Heterocyclic Carbene Ligand
Hansen, Christopher B.,Jordan, Richard F.,Hillhouse, Gregory L.
, p. 4603 - 4610 (2015/05/27)
A three-coordinate cobalt species, IPrCoCl{N-(SiMe3)2} [1; IPr = 1,3-bis(2,6-diisopropylphenyl)imidazolin-2-ylidene], was synthesized by the reaction of {IPrCoCl2}2 with NaN(SiMe3)2. Compound 1 is a useful starting material for low-coordinate (IPr)Co species. 1 reacts with 2,6-di-tert-butyl-4-methylphenol (BHT-H) via aminolysis of the Co-N bond to generate a three-coordinate phenoxide complex, IPrCoCl(O-2,6-tBu2-4-MeC6H2) (2). The reaction of 1 with 2,6-diisopropylaniline (NH2DIPP) generates IPrCoCl(NHDIPP) (4), which undergoes disproportionation to form a mixture of 4, {IPrCoCl2}2, and IPrCo(NHDIPP)2 (3). The same product mixture is formed by the reaction of 1 with Li[NH(DIPP)], which unexpectedly proceeds by amide exchange. Compound 3 was synthesized independently by the reaction of {IPrCoCl2}2 with 4 equiv of Li[NH(DIPP)]. The reaction of 1 with the bulkier lithium 2,6-dimesitylanilide (LiNHDMP) also proceeds by amide exchange to generate IPrCoCl(NHDMP) (5), which is stable toward disproportionation. Compounds 1 and 2 exhibit trigonal-planar geometries at cobalt in the solid state. The solid-state structure of 3 also contains a trigonal-planar cobalt center and exhibits close Co---H contacts involving the methine hydrogen atoms of the NH(DIPP) groups in the axial positions. The solid-state structure of 5 features an interaction between cobalt and a flanking aryl group of the anilide ligand, resulting in pyramidalization of the cobalt center. (Chemical Equation Presented).
Synthesis and reactivity of a conveniently prepared two-coordinate bis(amido) nickel(ii) complex
Lipschutz, Michael I.,Tilley, T. Don
supporting information; experimental part, p. 7146 - 7148 (2012/08/08)
A strictly two-coordinate nickel(ii) bis(amido) complex has been prepared and its reactivity towards a variety of small molecules is described. Ni[N(SiMe3)(DIPP)]2 reacts with DMAP and acetonitrile to form T-shaped three-coordinate complexes, and preliminary results show that Ni[N(SiMe3)(DIPP)]2 is a catalyst for the hydrosilation of olefins with secondary silanes at ambient temperature.
