19615-77-1Relevant academic research and scientific papers
NICKEL PRE-CATALYSTS AND RELATED COMPOSITIONS AND METHODS
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Page/Page column 40, (2015/05/26)
Described herein are nickel pre-catalysts and related compositions and methods. The nickel pre-catalysts may be activated to form catalysts which may be utilized in organic reactions.
A broadly applicable strategy for entry into homogeneous nickel(0) catalysts from air-stable nickel(II) complexes
Standley, Eric A.,Smith, Stacey J.,Mueller, Peter,Jamison, Timothy F.
supporting information, p. 2012 - 2018 (2014/05/20)
A series of air-stable nickel complexes of the form L2Ni(aryl) X (L = monodentate phosphine, X = Cl, Br) and LNi(aryl)X (L = bis-phosphine) have been synthesized and are presented as a library of precatalysts suitable for a wide variety of nickel-catalyzed transformations. These complexes are easily synthesized from low-cost NiCl2·6H2O or NiBr 2·3H2O and the desired ligand followed by addition of 1 equiv of Grignard reagent. A selection of these complexes were characterized by single-crystal X-ray diffraction, and an analysis of their structural features is provided. A case study of their use as precatalysts for the nickel-catalyzed carbonyl-ene reaction is presented, showing superior reactivity in comparison to reactions using Ni(cod)2. Furthermore, as the precatalysts are all stable to air, no glovebox or inert-atmosphere techniques are required to make use of these complexes for nickel-catalyzed reactions.
Inorganic Grignard Analogues. Reaction of Nickel Powder with Dihalogenotriorganophosphorus Compounds to form Nickel-(II) and -(III) Phosphine Complexes; Isolation of Planar (1-) and the crystal Structure of
Godfrey, Stephen M.,McAuliffe, Charles A.,Pritchard, Robin G.
, p. 2875 - 2882 (2007/10/02)
Reactions of dihalogenotriorganophosphorus R3PX2 (X = Br or I) with unactivated coarsegrain nickel powder have been investigated.The nature of the nickel phosphine complexes formed is remarkably dependent on both R and X.Where R Me and X = I the nickel(II) complexes are formed, analogous to, but not isostructural with, similar cobalt complexes of the same stoichiometry formed from cobalt powder and R3PI2.Quantitative electronic spectroscopic studies indicated that, surprisingly, the complexes all have predominantly square-planar geometry around nickel.Where R = Me and X = I, the nickel(III) complex is obtained in quantitative yield, the other product being diiodine.Reaction of nickel powder with Me2PhPI2 yields both the nickel(II) complex, , and the nickel(III) complex, .These observations again mirror analogous cobalt reactions.Reaction of the analogous dibromo compounds, R3PBr2, with nickel powder is extremely sensitive to the nature of R.Where R = Me, Et or Pnn no reaction occurs; where R3 = PhMe2 the square-planar complex and an octahedral complex of stoichiometry Ni(PPhMe2)2Br4 are obtained in equal yield.Where R3 = Ph2Prn the octahedral complex n)2Br4> is formed with a trace of the planar complex n)2Br2>, and where R = Ph the octahedral complex is formed in quantitative yield.The complex has been crystallographically characterised: monoclinic, space group P21/a, a = 10.018(2), b = 10.249(1), c = 10.138(1) Angstroem and Z = 2 (molecule centrosymmetric).
Inorganic Grignard Analogues. Reaction of Cobalt Powder with Triorganodiiodophosphorus Compounds to form . Crystal Structure of , and Isolation of the Novel Complexes and
Godfrey, Stephen M.,Lane, Helen P.,McAuliffe, Charles A.,Pritchard, Robin G.
, p. 1599 - 1604 (2007/10/02)
The reactions of a large number of triorganodiiodophosphorus compounds, R3PI2 n3, Bun3, PhMe2, Ph2Me, Ph2Prn, Ph3 (o-, m- or p-MeC6H4)Ph2, or (m-MeC6H4)3>, with unactivated cobalt metal in dry diethyl ether have been studied.All reactions produce the novel ionic complexes in quantitative yield, illustrated crystallographically for .However, where R3 = PhMe2 both the ionic complex and the cobalt(III) complex are produced from the same reaction.The previously reported isolation of the 'frozen transition-state complex' n3)3I8> from the reaction of Bun3PI2 with cobalt powder has been reinvestigated; when allowed to proceed to completion, the reaction produces the ionic complex described above.The compound Ph3PIBr reacts with cobalt powder to produce the mixed-halide ionic complex .All the complexes have been studied using Raman and visible spectroscopy, the latter confirming the tetrahedral geometry of the cobalt anion.Very little reaction is observed with the corresponding dibromophosphorus compounds, R3PBr2, but in some cases visible spectroscopic studies on the trace of complex formed suggest a tetrahedral cobalt(II) species, perhaps similar to the iodo-complexes described above.Additionally, Ph3SbI2 reacts with cobalt metal in an analogous way to Ph3PI2 to produce the novel complex .
