- Reactivity of (NNN)-pincer nickel(II) aryl complex towards oxidative carbon-heteroatom bond formation
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The reactivity of an (NNN)-Ni(II) aryl complex towards C–X bond formation upon exposure to a panel of one- and two-electron oxidants is reported. High selectivity for C(sp2)–N bond formation is observed in all cases, except under conditions when C–C bond formation is accessible. Preliminary mechanistic investigations indicate access to either a Ni(III) or Ni(IV) intermediate dependent on oxidant used and that C–N bond formation is more efficient via Ni(IV) pathway due to geometry of reactive species.
- Sousa e Silva, Felipe C.,Bloomer, Brandon J.,Wengryniuk, Sarah E.
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- Syntheses of transition metal methoxysiloxides
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The paper describes three methods for the preparation of methoxysiloxide complexes, a rare class of complexes of relevance to room temperature vulcanization (RTV) of polysiloxanes. The salt metathesis reaction involves the use of the recently described re
- Richers, Casseday P.,Bertke, Jeffery A.,Rauchfuss, Thomas B.
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p. 8756 - 8762
(2017/07/22)
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- Synthesis, reactivity, and catalytic application of a nickel pincer hydride complex
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The nickel(II) hydride complex [(MeN2N)Ni-H] (2) was synthesized by the reaction of [(MeN2N)Ni-OMe] (6) with Ph2SiH2 and was characterized by NMR and IR spectroscopy as well as X-ray crystallography. 2 was unstable in solution, and it decomposed via two reaction pathways. The first pathway was intramolecular N-H reductive elimination to give MeN2NH and nickel particles. The second pathway was intermolecular, with H2, nickel particles, and a five-coordinate Ni(II) complex [(MeN2N)2Ni] (8) as the products. 2 reacted with acetone and ethylene, forming [( MeN2N)Ni-OiPr] (9) and [(MeN 2N)Ni-Et] (10), respectively. 2 also reacted with alkyl halides, yielding nickel halide complexes and alkanes. The reduction of alkyl halides was rendered catalytically, using [(MeN2N)Ni-Cl] (1) as catalyst, NaOiPr or NaOMe as base, and Ph2SiH2 or Me(EtO)2SiH as the hydride source. The catalysis appears to operate via a radical mechanism.
- Breitenfeld, Jan,Scopelliti, Rosario,Hu, Xile
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p. 2128 - 2136
(2012/06/01)
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- Nickel complexes of a pincer NN2 ligand: Multiple carbon-chloride activation of CH2Cl2 and CHCl3 leads to selective carbon-carbon bond formation
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A new pincer-type bis(amino)amine (NN2) ligand and its lithium and nickel complexes, including Ni(II) methyl, ethyl, and phenyl complexes, were synthesized. The Ni(II) alkyl complexes react cleanly with alkyl halides including chlorides to form C-C coupled products and Ni(II) halides. More interestingly, the Ni(II) alkyls undergo unprecedented reactions with CH2Cl2 and CHCl3 to cleave all the C-Cl bonds and replace them with C-C bonds. The reactions are highly selective and lead to the first efficient catalytic coupling of CH2Cl2 with alkyl Grignards. A conversion of 82% and a turnover number of 47 are achieved within minutes. Coupling of CD2Cl2 and 1,1-dichloro-3,3-dimethylbutane with nBuMgCl is also realized. Preliminary mechanistic study suggests a radical initiated process for these reactions. Copyright
- Csok, Zsolt,Vechorkin, Oleg,Harkins, Seth B.,Scopelliti, Rosario,Hu, Xile
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p. 8156 - 8157
(2009/02/02)
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