20087-67-6Relevant articles and documents
Bridged and Unbridged Nickel-Nickel Bonds Supported by Cyclopentadienyl and Phosphine Ligand Sets
Ayres, Alexander J.,Cleaves, Peter A.,Cobb, Philip J.,Liddle, Stephen T.,Stewart, John C.,Vondung, Lisa,Wooles, Ashley J.
, p. 4735 - 4746 (2020)
A series of Ni complexes [Ni(Cl)2(PR3)2] with R = Me (1-Me), nPr (1-nPr), and nBu (1-nBu) and nickelocenes [Ni(η5-C5H4R′)2] with R′ = H (2-H), Me (2-Me), and SiMe3 (2-SiMe3) were synthesized and characterized. From these complexes, the synthesis of the Ni complexes [NiCl(PR3)(η5-C5H4R′)] R = Me, R′ = H (3-Me), R= nBu, R′ = H (3-nBu), R = nPr, R′ = H (3-nPr), R = Et, R′ = Me (4), and R = Et, R′ = SiMe3 (5) was achieved. All complexes were fully characterized, including single crystal X-ray crystallography. Complexes 3-R, 4, and 5 were then used to obtain homobimetallic Ni complexes with rare examples of unbridged Ni-Ni bonds [{Ni(η5-C5H5)(PR3)}2], with R = Me (7-Me) and R = nPr (7-nPr) being structurally characterized by single crystal X-ray diffraction. In order to probe the effect of bridging ligands on the Ni-Ni bond, the bridged complex [{Ni(μ:η5-C5H4CH2CH2P(tBu)2)}2] (8) was synthesized from the monomeric precursor [Ni(Cl)(κ1-η5-C5H4CH2CH2PtBu2)] (6). The Ni-Ni distances in 7-Me, 7-nPr, and 8 were found to be 2.407(1), 2.3931(6), and 2.6027(17) ?, respectively, the latter seemingly lengthened compared to the other two due to the tethered nature of the bridging ligand. DFT calculations confirm the presence of unbridged σ-bonds between the Ni atoms in 7-Me and 7-nPr and show that the bridging ligand in 8 has a minimal effect on the character of the Ni-Ni bond.
Evaluating a Dispersion of Sodium in Sodium Chloride for the Synthesis of Low-Valent Nickel Complexes**
Johnson Humphrey, Elliot L. B.,Kennedy, Alan R.,Sproules, Stephen,Nelson, David J.
, (2022/01/27)
The use of a sodium in sodium chloride dispersion is systematically evaluated for the synthesis of nickel(0) and nickel(I) complexes from readily-prepared nickel(II) precursors. A variety of complexes with phosphine and bipyridine-type ligands were accessed, although some reactions were found to produce mixtures of nickel(0) and nickel(I), and yields were highly variable. Several new nickel(I) complexes were obtained, and these were characterized using techniques including NMR spectroscopy, EPR spectroscopy, and single crystal X-ray diffraction analysis.
