31666-48-5Relevant academic research and scientific papers
Crystal structures of (acrylonitrile)bis(tri-o-tolyl phosphite)nickel and (ethylene)bis(tri-o-tolyl phosphite)nickel
Guggenberger, Lloyd J.
, p. 499 - 508 (1973)
The crystal and molecular structures of (acrylonitrile)bis(tri-o-tolyl phosphite)nickel, (C2H3CN)Ni[o-CH3C6H 4O)3P]2, and (ethylene)bis(tri-o-tolyl phosphite)nickel, (C2H4)Ni[(o-CH3C6H 4O)3P]2, have been determined by single-crystal X-ray techniques. Both structures have a nickel atom trigonally coordinated to two phosphite ligands and an olefin that is nearly in the PNiP plane; the dihedral angles between the Ni-olefin and Ni-P planes are 3.9 (1)° for the acrylonitrile complex and 6.6 (11)° for the ethylene complex. The Ni-P distances in the acrylonitrile complex are 2.121 (4) and 2.096 (4) A?; the Ni-C distances are 2.016 (10) and 1.911 (12) A?. The average Ni-P and Ni-C distances in the ethylene complex are 2.095 (2) and 2.02 (2) A?. The Olefin C-C bond length is 1.46 (2) A? for both complexes. The acrylonitrile, in addition to being more strongly bound to nickel than ethylene, is shifted relative to the ethylene geometry to maximize the CN involvement in the Ni-olefin bonding. Comparisons are made between the acrylonitrile and ethylene-phosphite structures and that of (ethylene)bis(triphenylphosphine)nickel for structural correlations with the steric and electronic differences in the molecules. Crystals of (C2H3CN)Ni[(o-CH3C6H 4O)3P]2 are monoclinic, space group P21/c, with cell dimensions of a = 17.143 (9), b = 12.087 (9), c = 19.806 (20) A?, and β = 91.09 (14)°. The R factor is 0.097 for the least-squares refinement of 2182 observed reflections. Crystals of (C2H4)Ni[(o-CH3C6H 4O)3P]2 are monoclinic, space group Pc, with cell dimensions of a = 11.812 (4), b = 9.823 (4), c = 18.337 (9) A?, and β = 109.50 (9)°. The R factor for 2059 observed reflections is 0.088. Copyright 1973 by the American Chemical Society.
Olefin complexes of nickel(0). 4. Equilibria in solutions containing P(O-o-tolyl)3 and cyanoolefins
Tolman, Chadwick A.
, p. 614 - 621 (2008/10/08)
31P and 1H NMR and IR spectroscopy and spectrophotometry are used to demonstrate the presence of both olefin and nitrile complexes in solutions containing cyanoolefins, P(O-o-tol)3 (tol = tolyl), and nickel(0). Coordination of the olefinic double bond is favored by a terminal location and by conjugation with the nitrile group. Coordination of the nitrile nitrogen is favored by conjugation and by increased concentrations of free P(O-o-tol)3. A number of equilibrium constants and electronic spectra in benzene at 25 °C are reported and discussed in terms of the structures of the cyanoolefins.
Formation of olefin complexes of Nickel(0). 5. Steric and electronic effects of phosphorus ligands
Tolman,Seidel,Gosser
, p. 1391 - 1396 (2008/10/08)
Spectrophotometric measurements by IR and vis/UV on solutions containing olefins, phosphorus ligands, and nickel(0) show that competition for coordination is strongly affected by both olefin structure and the steric and electronic properties of the phosph
Ethylene[bis(tri-o-tolyl phosphite)]nickel(0)
Seidel,Tolman
, p. 2354 - 2357 (2008/10/08)
The preparation and properties of ethylene[bis(tri-o-tolyl phosphite)]nickel(0) are described. The ethylene appears in the proton nmr spectrum at τ 8.06, 3.3 ppm to high field of free C2H4. The v(C=C) of ethylene in the complex was observed in the Raman spectrum at 1487 cm-1, 136 cm-1, lower than that of free C2H4. Spectrophotometric measurements show that addition of tri-o-tolyl phosphite to a solution of the ethylene complex rapidly converts it to tris- and tetrakis(tri-o-tolyl phosphite)nickel complexes. The equilibrium constant K1, to give the tris-phosphite complex via the reaction (C2H4)-NiL2 + L ?K1NiL3 + C2H4, has a value of 6.8 ± 0.5 × 10-3 in benzene at 28°.
