4 research outputs found
Synthesis, Reactivity, and Catalytic Application of a Nickel Pincer Hydride Complex
No full textThe nickelÂ(II) hydride complex [(<sup>Me</sup>N<sub>2</sub>N)ÂNi-H]
(<b>2</b>) was synthesized by the reaction of [(<sup>Me</sup>N<sub>2</sub>N)ÂNi-OMe] (<b>6</b>) with Ph<sub>2</sub>SiH<sub>2</sub> and was characterized by NMR and IR spectroscopy as well
as X-ray crystallography. <b>2</b> was unstable in solution,
and it decomposed via two reaction pathways. The first pathway was
intramolecular N–H reductive elimination to give <sup>Me</sup>N<sub>2</sub>NH and nickel particles. The second pathway was intermolecular,
with H<sub>2</sub>, nickel particles, and a five-coordinate NiÂ(II)
complex [(<sup>Me</sup>N<sub>2</sub>N)<sub>2</sub>Ni] (<b>8</b>) as the products. <b>2</b> reacted with acetone and ethylene,
forming [(<sup>Me</sup>N<sub>2</sub>N)ÂNi-O<sup><i>i</i></sup>Pr] (<b>9</b>) and [(<sup>Me</sup>N<sub>2</sub>N)ÂNi-Et] (<b>10</b>), respectively. <b>2</b> also reacted with alkyl
halides, yielding nickel halide complexes and alkanes. The reduction
of alkyl halides was rendered catalytically, using [(<sup>Me</sup>N<sub>2</sub>N)ÂNi-Cl] (<b>1</b>) as catalyst, NaO<sup><i>i</i></sup>Pr or NaOMe as base, and Ph<sub>2</sub>SiH<sub>2</sub> or MeÂ(EtO)<sub>2</sub>SiH as the hydride source. The catalysis appears
to operate via a radical mechanism
Synthesis, Reactivity, and Catalytic Application of a Nickel Pincer Hydride Complex
No full textThe nickelÂ(II) hydride complex [(<sup>Me</sup>N<sub>2</sub>N)ÂNi-H]
(<b>2</b>) was synthesized by the reaction of [(<sup>Me</sup>N<sub>2</sub>N)ÂNi-OMe] (<b>6</b>) with Ph<sub>2</sub>SiH<sub>2</sub> and was characterized by NMR and IR spectroscopy as well
as X-ray crystallography. <b>2</b> was unstable in solution,
and it decomposed via two reaction pathways. The first pathway was
intramolecular N–H reductive elimination to give <sup>Me</sup>N<sub>2</sub>NH and nickel particles. The second pathway was intermolecular,
with H<sub>2</sub>, nickel particles, and a five-coordinate NiÂ(II)
complex [(<sup>Me</sup>N<sub>2</sub>N)<sub>2</sub>Ni] (<b>8</b>) as the products. <b>2</b> reacted with acetone and ethylene,
forming [(<sup>Me</sup>N<sub>2</sub>N)ÂNi-O<sup><i>i</i></sup>Pr] (<b>9</b>) and [(<sup>Me</sup>N<sub>2</sub>N)ÂNi-Et] (<b>10</b>), respectively. <b>2</b> also reacted with alkyl
halides, yielding nickel halide complexes and alkanes. The reduction
of alkyl halides was rendered catalytically, using [(<sup>Me</sup>N<sub>2</sub>N)ÂNi-Cl] (<b>1</b>) as catalyst, NaO<sup><i>i</i></sup>Pr or NaOMe as base, and Ph<sub>2</sub>SiH<sub>2</sub> or MeÂ(EtO)<sub>2</sub>SiH as the hydride source. The catalysis appears
to operate via a radical mechanism
Bimetallic Oxidative Addition in Nickel-Catalyzed Alkyl–Aryl Kumada Coupling Reactions
No full textThe
mechanism of alkyl–aryl Kumada coupling catalyzed by
the nickel pincer complex Nickamine was studied. Experiments using
radical-probe substrates and DFT calculations established a bimetallic
oxidative addition mechanism. Kinetic measurements showed that transmetalation
rather than oxidative addition was the turnover-determining step.
The transmetalation involved a bimetallic pathway
Synthesis of Adipic Acid, 1,6-Hexanediamine, and 1,6-Hexanediol via Double‑<i>n</i>‑Selective Hydroformylation of 1,3-Butadiene
No full textA method for the synthesis of the
industrially relevant monomers
adipic acid, 1,6-hexanediol (HDO), and 1,6-hexanediamine (HMD) via
isomerizing hydroformylation of 1,3-butadiene is described. The aldehyde
intermediates are protected in situ as acetals to avoid hydrogenation
to pentanal. Adipic aldehyde diacetal is obtained in good yields,
and the first examples for the conversion toward adipic acid, 1,6-hexanediol,
and 1,6-hexanediamine are shown
