167638-79-1Relevant academic research and scientific papers
2-Pyridyl-phosphine and -diphosphine complexes of nickel(0), their reactivity (including aqueous solution chemistry), and some related, incidental methylphosphonium iodides
Le Page, Matthew D.,Patrick, Brian O.,Rettig, Steven J.,James, Brian R.
, p. 276 - 288 (2015/06/02)
The chemistry of Ni0-dicarbonyl(pyridylphosphine) complexes of the type Ni(CO)2L2, where L is either P-bonded PPh3-npyn (n = 1-3, py = 2-pyridyl; abbreviated PNx, x = 1-3, species 1a-c), or L2 is (P-P)-chelated py2P(CH2)2Ppy2 or, is further developed from earlier studies by our group [the P-P ligands are abbreviated, respectively, as d(py)pe and d(py)pcp]. The complexes are synthesized from C6H6 solutions of Ni(CO)2(PPh3)2, and the Ni(CO)2(PPh3)(PNx) intermediates (1a-c) are detected; Ni(CO)2[d(py)pcp] (2b) is shown by X-ray analysis to have a distorted tetrahedral structure; and the NiII species [Ni2(CO)4(μ-PN2)2]Cl4 is isolated from a light-induced reaction in CDCl3 solution. Complex 2b dissolves in water at ambient conditions via a net double protonation of pyridyl N-atoms, the {Ni(CO)2[2H-d(py)pcp]}2+ being isolated as the bis(triflate) salt; the dication decomposes in minutes with formation of [Ni(H2O)6]2+, CO, the phosphine dioxide, and deprotonated d(py)pcp. Some twenty-two Ni0 complexes, exemplified by Ni(P-P)2, Ni(PNx)2(P-P), Ni(PNx)4, and related PPh3- and Ph2P(CH2)2PPh2 (dppe)-containing species, are synthesized from Ni(1,5-COD)2 and their reactivity studied; for example, oxidative addition of MeI generates trans-Ni(Me)(I)(PN3)2 and trans-Ni(Me)(I)(P-P)2 but, with non-pyridyl containing reactants such as Ni(PPh3)4 and Ni(dppe)2, only (monomethyl)phosphonium iodides are formed. Such iodides, and the bis(methyl) analogues [(CH3)2(diphosphine)]I2, are then studied for clarification of some observed Ni chemistry. The NMR trends (a)-(d) are noted within the series of Ni0 complexes, and are rationalized: (a) the 2JPP values in 1a-c, and the separation between the two doublets, parallel the number of N-atoms present; (b) the 31P{1H} signals in the Ni(PNx)4 and Ni(PNx)2(P-P) complexes shift downfield in the order PN1 2 3 within linear dependences; (c) the 2JPP values for the Ni(PR3)2(P-P) complexes (R = Ph and PNx) decrease in the order R = Ph > PN1 > PN2 > PN3; (d) and the separation between the two 31P{1H} triplets of the Ni(PNx)2(P-P) complexes generally depends on the relative numbers of phenyl and pyridyl groups.
Nickel(II) and nickel(0) complexes containing 2-pyridylphosphine ligands, including water-soluble species
Baird, Ian R.,Smith, Martin B.,James, Brian R.
, p. 291 - 298 (2008/10/08)
The paramagnetic, S=1, NiX2L2 (X = Cl or Br, L = PPh(3-n)py(n), n = 1-3), and diamagnetic NiBr2[d(py)pe] (4b) complexes have been isolated, generally as solvates, where py = 2-pyridyl, and d(py)pe=py2P(CH2)2Ppy2. Also isolated are the diamagnetic Ni(CO)2(
