15628-25-8Relevant articles and documents
Effect of the Bite Angle of Diphosphine Ligands on Activity and Selectivity in the Nickel-catalysed Hydrocyanation of Styrene
Kranenburg, Mirko,Kamer, Paul C. J.,Leeuwen, Piet W. N. M. van,Vogt, Dieter,Keim, Wilhelm
, p. 2177 - 2178 (1995)
The application of diphosphines with large bite angles (βn = 101-109 deg) in nickel catalysts leads to successful, regioselective hydrocyanation of styrene.
Nickel-catalysed Substitution Reactions of Allylic Compounds with Soft Nucleophiles: an Efficient Alternative to Palladium Catalysis
Bricout, Herve,Carpentier, Jean-Francois,Mortreux, Andre
, p. 1863 - 1864 (1995)
Substitution reactions of allyl alcohol derivatives 1a-c with diethylamine, phenol and dimethyl malonate are efficiently carried out in the presence of Ni(dppb)2 (dppb = 1,2-diphenylphosphinobutane) as catalyst and ammonium salts or bases as promoters or co-reagents.
Synergy between Experimental and Computational Chemistry Reveals the Mechanism of Decomposition of Nickel-Ketene Complexes
Staudaher, Nicholas D.,Arif, Atta M.,Louie, Janis
supporting information, p. 14083 - 14091 (2016/11/06)
A series of (dppf)Ni(ketene) complexes were synthesized and fully characterized. In the solid state, the complexes possess η2-(C,O) coordination of the ketene in an overall planar configuration. They display similar structure in solution, except in some cases, the η2-(C,C) coordination mode is also detected. A combination of kinetic analysis and DFT calculations reveals the complexes undergo thermal decomposition by isomerization from η2-(C,O) to η2-(C,C) followed by scission of the C=C bond, which is usually rate limiting and results in an intermediate carbonyl carbene complex. Subsequent rearrangement of the carbene ligand is rate limiting for electron poor and sterically large ketenes, and results in a carbonyl alkene complex. The alkene readily dissociates, affording alkenes and (dppf)Ni(CO)2. Computational modeling of the decarbonylation pathway with partial phosphine dissociation reveals the barrier is reduced significantly, explaining the instability of ketene complexes with monodentate phosphines.
Monomeric three-coordinate N-heterocyclic carbene nickel(I) complexes: Synthesis, structures, and catalytic applications in cross-coupling reactions
Matsubara, Kouki,Fukahori, Yukino,Inatomi, Takahiro,Tazaki, Saeko,Yamada, Yuji,Koga, Yuji,Kanegawa, Shinji,Nakamura, Toshikazu
supporting information, p. 3281 - 3287 (2016/10/21)
A series of three-coordinate monovalent nickel halide complexes bearing N-heterocyclic carbene (NHC) ligands, i.e., NiCl(IPr)(L) [L = pyridine, P(OPh)3, bis(diphenylphosphino)butane (dppb), IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene], NiX(IMes)(PPh3) (X = Cl and Br, IMes = 1,3-bis(mesityl)imidazol-2-ylidene), were prepared. The complexes were identified using NMR spectroscopy, superconducting quantum interference device (SQUID), and X-ray crystallography. Additionally, ESR spectra of NiCl(IPr)(pyridine) were taken in toluene. These complexes had three-coordinate Y-shaped geometries in both the solid and solution states. The compounds containing IPr showed equilibrium between the monomeric and dimeric forms, with liberation of ligands. Addition of 1,2-bis(diphenylphosphino)ethane and 1,3-bis(diphenylphosphino)propane to the dinickel(I) IPr complex instead of dppb resulted in heterolytic cleavage to nickel(0) and nickel(II) species. Catalysis of Suzuki cross-coupling and Buchwald-Hartwig amination of aryl bromide using the complexes was investigated. The efficiencies in the amination of aryl bromide depended strongly on the additional donor ligands.
Fundamental studies and development of nickel-catalyzed trifluoromethylthiolation of aryl chlorides: Active catalytic species and key roles of ligand and traceless MeCN additive revealed
Yin, Guoyin,Kalvet, Indrek,Englert, Ulli,Schoenebeck, Franziska
, p. 4164 - 4172 (2015/04/14)
A catalytic protocol to convert aryl and heteroaryl chlorides to the corresponding trifluoromethyl sulfides is reported herein. It relies on a relatively inexpensive Ni(cod)2/dppf (cod = 1,5-cyclooctadiene; dppf = 1,1′-bis(diphenylphosphino)ferrocene) catalyst system and the readily accessible coupling reagent (Me4N)SCF3. Our computational and experimental mechanistic data are consistent with a Ni(0)/Ni(II) cycle and inconsistent with Ni(I) as the reactive species. The relevant intermediates were prepared, characterized by X-ray crystallography, and tested for their catalytic competence. This revealed that a monomeric tricoordinate Ni(I) complex is favored for dppf and Cl whose role was unambiguously assigned as being an off-cycle catalyst deactivation product. Only bidentate ligands with wide bite angles (e.g., dppf) are effective. These bulky ligands render the catalyst resting state as [(P-P)Ni(cod)]. The latter is more reactive than Ni(P-P)2, which was found to be the resting state for ligands with smaller bite angles and suffers from an initial high-energy dissociation of one ligand prior to oxidative addition, rendering the system unreactive. The key to effective catalysis is hence the presence of a labile auxiliary ligand in the catalyst resting state. For more challenging substrates, high conversions were achieved via the employment of MeCN as a traceless additive. Mechanistic data suggest that its beneficial role lies in decreasing the energetic span, therefore accelerating product formation. Finally, the methodology has been applied to synthetic targets of pharmaceutical relevance.
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.
Nickelacyclic carboxylates derived from 3-hexyne and CO2 and their application in the synthesis of a new muconic acid derivative
Langer, Jens,Goerls, Helmar,Walther, Dirk
, p. 60 - 67 (2012/03/13)
The mononuclear unsaturated nickelalactones [Ni{C(Et)C(Et)-COO}(DBU) 2] (1) and [Ni{C(Et)C(Et)-COO}(dcpe)] (2) were synthesized by oxidative coupling of CO2 and 3-hexyne at zero-valent nickel in presence of DBU or dpce, respectively.
The first catalytic synthesis of an acrylate from CO2 and an alkene-A rational approach
Lejkowski, Michael L.,Lindner, Ronald,Kageyama, Takeharu,Bodizs, Gabriella E.,Plessow, Philipp N.,Mueller, Imke B.,Schaefer, Ansgar,Rominger, Frank,Hofmann, Peter,Futter, Cornelia,Schunk, Stephan A.,Limbach, Michael
supporting information, p. 14017 - 14025 (2013/01/15)
For more than three decades the catalytic synthesis of acrylates from the cheap and abundantly available C1 building block carbon dioxide and alkenes has been an unsolved problem in catalysis research, both in academia and industry. Herein, we
Synthetic analogs for evaluating the influence of N-H...S hydrogen bonds on the formation of thioester in acetyl coenzyme a synthase
Ariyananda, Piyal W. G.,Kieber-Emmons, Matthew T.,Yap, Glenn P. A.,Riordan, Charles G.
, p. 4359 - 4369 (2009/10/16)
A series of square planar methylnickel(II) complexes, (dppe)Ni(Me)(SAr) (dppe = 1,2-bis(diphenylphosphino)ethane); 2. Ar = phenyl; 3. Ar = pentafluorophenyl; 4. Ar = o-pivaloylaminophenyl; 5. Ar = p-pivaloylaminophenyl; (depe)Ni(Me)(SAr), (depe = 1,2-bis(diethylphosphino)ethane); 7. Ar = phenyl; 8. Ar = pentafluorophenyl; 9. Ar = o-pivaloylaminophenyl; 10. Ar = p-pivaloylaminophenyl), were synthesized via the reaction of (dppe)NiMe 2 (1) and (depe)NiMe2 (6) with either the corresponding thiol or disulfide. These complexes were characterized by various spectroscopic methods including 31P NMR, 1H NMR, 13C NMR and infrared spectroscopies and in most cases by X-ray diffraction analyses. Solid state and solution measurements establish that 4 and 9 contain intramolecular N-H...S bonds. Carbonylation of the complexes 2-4, 7-10 leads to (dRpe)Ni(CO)2 and MeC(O)SAr via the intermediacy of the acylnickel adducts, (dRpe)Ni(C(O)Me)(SAr), detected at low temperature by 31P NMR spectroscopy. Consistent with experimental observations, density functional theory results reveal that the intramolecular hydrogen bond in 9 stabilizes the acylnickel adduct compared with its non-hydrogen-bonded adduct, 10. Oxidative addition of MeC(O)SC6F5 to (dRpe)Ni(COD) followed by spontaneous decarbonylation proceeds in variable yields generating 3 and 8.
Studies of structural effects on the half-wave potentials of mononuclear and dinuclear nickel(II) diphosphine/dithiolate complexes
Redin, Kendra,Wilson, Aaron D.,Newell, Rachel,DuBois, M. Rakowski,DuBois, Daniel L.
, p. 1268 - 1276 (2008/10/09)
Two series of mononuclear Ni(II) complexes of the formula (PNP)Ni(dithiolate) where PNP = R2PCH2N(CH 3)CH2-PR2, R = Et and Ph, have been synthesized containing dithiolate ligands that vary from five- to seven-membered chelate rings. Two series of dinuclear Ni(II) complexes of the formula {[(diphosphine)Ni]2(dithiolate)}(X)2 (X = BF4 or PF6) have been synthesized in which the chelate ring size of the dithiolate and diphosphine ligands have been systematically varied. The structures of the alkylated mononuclear complex, [(PNPEt)Ni(SC 2H4SMe)]OTf, and the dinuclear complex, [(dppeNi) 2(SC3H6S)](BF4)2, have been determined by X-ray diffraction studies. The complexes have been studied by cyclic voltammetry to determine how the half-wave potentials of the Ni(II/I) couples vary with chelate ring size of the ligands. For the mononuclear complexes, this potential becomes more positive as the natural bite angle of the dithiolate ligand increases. However, the potentials of the Ni(II/I) couples of the dinuclear complexes do not show a dependence on the chelate ring size of the ligands. Other aspects of the reduction chemistry of these complexes have been explored.
