- Selective cis-Isomerization of 1-Pentene Catalyzed by Ni(I)-Triphenylphosphine Complexes
-
Selective cis-isomerization of 1-pentene was carried out by NiX(PPh3)3 (X = halogen and pseudohalogen).First-order plots were obtained except for the iodo-complex.The addition of tin(II) chloride increased both activities and ratios of cis-2-pentene to the trans-isomer.Protic solvents accelerated the isomerization.Isotopic exchange between C2D4 and C2H4 or 1-pentene reveals that a metal hydride addition-elimination mechanism is operative.
- Kanai, Hiroyoshi,Kushi, Kenji,Sekanoue, Kei,Kishimoto, Nobuji
-
-
Read Online
- Synthesis and reactivity of NiII(Phpy)2 (Phpy = 2-phenylpyridine)
-
This article describes the synthesis and reactivity of Ni II(Phpy)2 (Phpy = 2-phenylpyridine) with a variety of oxidants, including O2, Br2, PhICl2, N-fluoropyridinium salts, CuII salts, and N-halosuccinimides. High-oxidation-state Ni intermediates were not detected in any of these transformations. In all cases, the major organic product resulted from oxidatively induced C-C bond formation to generate the Phpy-Phpy dimer. Traces (2-16%) of organic products resulting from C-O, C-Br, C-Cl, and C-N bond-forming reductive elimination were also observed.
- Higgs, Andrew T.,Zinn, Paul J.,Sanford, Melanie S.
-
p. 5446 - 5449
(2011/01/03)
-
- Metallated triphenylphosphinimine complexes
-
The reagent [(o-C6H4PPh2NSiMe3)Li]2 ·Et2O 1 reacted with BCl3 affording (o-C6H4PPh2NSiMe3)BCl2 4. Similarly reaction of 1 with Me2AlCl resulted in a 1:1 mixture of (o-C6H4PPh2NSiMe3)AlMe2 5 and (o-C6H4PPh2NSiMe3)-Al(Me)Cl 6 while the analogous reaction of 1 with GaCl3 gave (o-C6H4PPh2NSiMe3)2 Ga(o-C6H4PPh2NH) 7. The analogous compound [Li(o-C6H4PPh2NPh)]2· Et2O 2 was used to make (o-C6H4PPh2NPh)GaCl2 8, while reaction of 2 with Me2AlCl gave a mixture of [(o-C6H4PPh2NPh)AlCl2] 9 and the salt [(o-C6H4PPh2NPh)2Al] [AlMeCl3] 10. The compound 2 also reacts with PdCl2(COD) affording [Pd(o-C6H4PPh2NPh) (μ-Cl)]2 11 and [Pd(o-C6H4PPh2 NPh)2] 12. Similarly, the complexes [Ni(o-C6H4 PPh2NPh)2] 13 and [Ni(o-C6H4PPh2N(3,5-C6H3 Me2))2] 14 were prepared. The compounds 4-14 have been structurally characterized by X-ray methods.
- Wei, Pingrong,Chan, Katie T.K.,Stephan, Douglas W.
-
p. 3804 - 3810
(2007/10/03)
-
- Reactions of Aluminium Tribromide with Tetrakis(triphenylphosphine) nickel(0) and Tetrakis(triethylphosphite)nickel(0) Complexes
-
Reactions of aluminium tribromide with the Ni(0) phosphine and phosphite complexes are studied by EPR method. AlBr3 was found to cause the oxidation of the transition metal in the (PPh3)4Ni complex to the univalent state with the formation of the tetracoordinated (PPh3)3NiBr complex. With an excess of AlBr3, the phosphine ligands are eliminated from the coordination sphere of Ni(I), and the coordinatively unsaturated complexes are destroyed to give the colloidal nickel. In the reaction of (P(OEt)3)4Ni with AlBr 3, Ni(0) is also oxidized to Ni(I), but the acido ligand is not eliminated even with a 15-fold excess of the Lewis acid. The activity of catalytic systems on the basis of the Ni(0) phosphine complexes and the Lewis acids in the low-molecular oligomerization reactions of olefines is determined by the cationic coordinatively unsaturated Ni(I) complexes formed in these systems.
- Kraikivskii,Saraev,Matveev,Zelinskii,Tkach
-
p. 431 - 434
(2008/10/08)
-
- On the interaction of a nickel(0) complex with mono- and di-bromo derivatives of cyclopropane. Novel η3-allylnickel complexes
-
The interaction of (η2-ethylene)bis(triphenylphosphine)nickel(0) with 1-bromo-2-methyl-2-phenyl- and 1,1,-dibromo-2-methyl-2-phenyl-cyclopropane has been studied.These reactions were expected to proceed with opening of the three-membered ring a
- Peganova, T. A.,Isaeva, L. S.,Petrovskii, P. V.,Kravtsov, D. N.
-
p. 397 - 403
(2007/10/02)
-
- Electroanalytical Investigation on Ligand-disproportionation and -exchange Equilibria in Nickel(II) and Nickel(I) Halide Phosphine Complexes in Acetonitrile
-
Redox reactions of complexes (L = PPh3; X = Cl, Br, or I) at platinum electrodes in acetonitrile solution have been investigated by cyclic voltammetry, controlled-potential electrolysis, and spectrophotometry.The complexes undergo quantitative ligand disproportionation giving ionic species, and the nickel(I) complexes obtained as reduction products exhibit ligand-exchange equilibria.The nickel(0) species obtained in a further reduction process is not involved in any ligand-exchange reaction.The results demonstrate that the degree of reversibility of the redox processes depends markedly on the nature of the ligand set present in both the redox partners.The dependence of the reduction potentials on the nature of the halide ligands is discussed.
- Bontempelli, Gino,Magno, Franco,Nobili, Maria De,Schiavon, Gilberto
-
p. 2288 - 2293
(2007/10/02)
-