Methyl Transfer from Methylcobaloxime to (Triphos)Ni(PPh3): Relevance to the Mechanism of Acetyl Coenzyme A Synthase
摘要:
The zerovalent nickel complex, (triphos)Ni(PPh3), is quantitatively alkylated by a methylcobaloxime reagent. Independent chemical synthesis confirms the nickel-containing product as the cation, [(triphos)NiMe](+). These studies provide small molecule precedent for a Ni(0) nucleophile during acetyl coenzyme A synthase (ACS) biocatalysis. That the corresponding (triphos)NiCO is not a substrate for the reaction provides a chemical-based rationale for ordered binding of methyl followed by CO.
An Anionic Zerovalent Nickel Carbonyl Complex Supported by a Triphosphine Borate Ligand: An Ni−C⋮O−Li Isocarbonyl
作者:Hongyi Hou、Arnold L. Rheingold、Clifford P. Kubiak
DOI:10.1021/om049601f
日期:2005.1.1
An anionic zerovalent nickel carbonyl complex, [Ni(PhBP3XCO)] [Li(TiMED)] (1). Supported by a triphosphine borate ligand was prepared and structurally characterized. The solid state. structure shows the coordination of Li+ to the O atom of the CO ligand. The isocarbonyl structure indicates strong electron donor ability of the [PhBP3] ligand and charge redistribution to the carbonyl oxygen. Results of a DFT calculation support this view. Complex 1 represents the first example of a Lewis acid O atom adduct of a Ni(0) carbonyl complex.