14126-32-0Relevant academic research and scientific papers
Magnetic coupling in the fullerene dimer {Co(Ph3P)(C 6H5CN)}2(μ2-η2: η2-C60)2 with two zerovalent cobalt atoms as bridges
Konarev, Dmitri V.,Troyanov, Sergey I.,Nakano, Yoshiaki,Ustimenko, Ksenya A.,Otsuka, Akihiro,Yamochi, Hideki,Saito, Gunzi,Lyubovskaya, Rimma N.
, p. 4038 - 4041 (2013)
The magnetic metal-bridged fullerene dimer {Co(Ph3P)(C 6H5CN)}2(μ2-η2, η2-C60)2 was synthesized for the first time and studied by X-ray crystallography and magnetic susceptibility methods. The dimers, in which two fullerene C60 cages are η2-bonded through two Co0 atoms (S = 1/2), have a triplet (S = 1) state and transfer to a diamagnetic singlet (S = 0) ground state below 50 K (J/kB = -28.6 K). The theoretical calculations show that C60 can work as an efficient spin coupler between paramagnetic metals.
Simpler and Cleaner Synthesis of Variously Capped Cobalt Nanocrystals Applied in the Semihydrogenation of Alkynes
Moisset, A.,Petit, C.,Petit, M.,Salzemann, C.,Sodreau, A.,Vivien, A.
, p. 13972 - 13978 (2020/10/09)
Unlike the classical organometallic approach, we report here a synthetic pathway requiring no reducing sources or heating to produce homogeneous hexagonal-close-packed cobalt nanocrystals (Co NCs). Involving a disproportionation process, this simple and fast (6 min) synthesis is performed at room temperature in the presence of ecofriendly fatty alcohols to passivate Co NCs. Through a recycling step, the yield of Co NCs is improved and the waste generation is limited, making this synthetic route cleaner. After an easy exchange of the capping ligands, we applied them as unsupported catalysts in the stereoselective semihydrogenation of alkynes.
Thermochemistry of adducts of some bivalent transition metal bromides with triphenylphosphine
Dunstan, Pedro Oliver
, p. 100 - 105 (2008/10/09)
The compounds [MBrm(L)n] (where M is Mn(II), Fe(II), Co(II), Ni(II), Cu(I) or Zn(II); L = triphenyphosphine (tpp); m = 1 or 2; n = 1.5, 2 or 3) were synthesized and characterized by melting points, elemental analysis, thermal analysis and electronic and IR spectroscopy. The enthalpies of dissolution of the adducts, metal(II) bromides and triphenylphosphine in methanol or in a solution of 10% (v/v) triethanolamine, 40% (v/v) acetonitrile and 50% (v/v) methanol were measured and by using thermochemical cycles, the following thermochemical parameters for the adducts, have been determined: the standard enthalpies for the Lewis acid/base reaction (ΔrH θ), the standard enthalpies of formation (Δ fHθ), the standard enthalpies of decomposition (ΔDHθ), the lattice standard enthalpies (ΔMHθ) and the standard enthalpies of the Lewis acid/base reaction in the gaseous phase (ΔrH θ(g)). The mean bond dissociation enthalpies of the metal(II)-phosphorus bonds (D?(M-P)) have been estimated.
Complexes of functional phosphines. 23. PPh3 and β-ketophosphine complexes of cobalt(II). Crystal and molecular structures of CoCl2[Ph2PCH2C(O)Ph]2 and Co2(CO)6[Ph2PCH2C(O)Ph]2 and of the trinuclear, mixed-metal complex [(Ph3P)2 ...
Braunstein, Pierre,Kelly, David G.,Dusausoy, Yves,Bayeul, Daniel,Lanfranchi, Maurizio,Tiripicchio, Antonio
, p. 233 - 242 (2008/10/08)
Full title: Complexes of functional phosphines. 23. PPh3 and β-ketophosphine complexes of cobalt(II). Crystal and molecular structures of CoCl2[Ph2PCH2C(O)Ph]2 and Co2(CO)6[Ph2PCH2C(O)Ph]2 and of the trinuclear, mixed-metal complex [(Ph3P)2Ag(μ-Cl)2Co(μ-Cl) 2Ag(PPh3)2]·0.5OEt2. The solution chemistry of cobalt(II) ketophosphine complexes CoX2[Ph2PCH2C(O)Ph]2 (1a, X = Cl; 1b, X = Br; 1c, X = I) has been examined and compared to that of [CoX2(PPh3)2] (2a, X = Cl; 2b, X = Br; 2c, X = I). All the complexes undergo a tetrahedral-octahedral equilibrium in methanol. This is facilitated by solvent coordination rather than by the ligand's keto functions. Some degree of ligand displacement also occurs. The crystal structure of 1a has been elucidated, showing a pseudotetrahedral cobalt(II) geometry. A long interligand hydrogen-bond, not present in powder samples, is observed between the methylene group of a Ph2PCH2C(O)Ph ligand and the ketone function of the other Ph2PCH2C(O)Ph ligand. 1a reacts with Na[Co(CO)4] to afford the crystallographically characterized, metal-metal bonded centrosymmetric complex Co2(CO)6[Ph2PCH2C(O)Ph]2 (5) (Co-Co = 2.666(1) A?). The reactivity of 1a with AgBF4 and TlPF6 has also been examined and compared to that of 2a where the latter is reacted in the presence and absence of excess phosphine. Notable reaction products include the square planar cobalt(II) complex [Co{Ph2PCH2C(O)Ph}{Ph2PCH 2C(O)Ph}Cl]PF6 (6), which slowly transforms in solution to the octahedral complex [Co{Ph2PCH2C(O)Ph}2{Ph2PCH 2C(O)Ph}Cl]PF6 (7). Reaction with AgBF4 under similar conditions affords the silver phosphine complex Ag{Ph2PCH2C(O)Ph}2Cl (8). 2a reacts with AgBF4 to give [Ag-(PPh3)2]BF4, but additionally in the presence PPh3 gives (Ph3P)2Ag(μ-Cl)2Co(μ-Cl) 2Ag(PPh3)2 (13). The latter formulation involving a central CoCl42- core, and an almost linear Ag-Co-Ag arrangement has been confirmed by single-crystal X-ray diffraction. The solid state structures of 1a, 5, and 13·0.5OEt2 have been determined by single-crystal X-ray analysis. 1a crystallizes in the monoclinic space group P21/c with Z = 4 in a unit cell of dimensions a = 10.985(2) A?, b = 17.236(4) A?, c = 19.547(4) A?, and β = 104.87(2)°. 5 crystallizes in the triclinic space group P1 with Z = 1, a = 8.916(2) A?, b = 11.177(7) A?, c = 12.009(4) A?, α = 81.15(5)°, β = 76.39(2)°, and γ = 67.47(3)°. Complex 13·0.5OEt2, crystallizes in the monoclinic space group P21/c with Z = 8, a = 21.840(5) A?, b = 17.664(6) A?, c = 36.890(7) A?, and β = 93.14(2)°.
Homogeneous Isomerization of 1-Butene Catalyzed by -NaBH4 Systems (M=Co, Ni, X=Halides, SCN, PR3=PPhnEt3-n) - Acceleration by Phosphine Addition and Stereoselectivity
Kanai, Hiroyoshi,Sakai, Shigeyoshi,Sakatani, Takenobu
, p. 1589 - 1594 (2007/10/02)
The stoichiometric or a little excess amount of NaBH4 was treated with (M=Co, Ni, X=halides, SCN, PR3=PPhnEt3-n) in THF-1,2-dimethoxyethane to form monohydride species which were active for isomerization of 1-butene.The reaction was accelerated by excess PPh3 in -NaBH4 systems.Other catalytic systems have optimum ratios of excess phosphine to metal for getting maximum activities.Thiocyanate-metal complexes are the most active in each Co- and Ni-catalyst system.Cis-selectivity depends on the cone angle of PR3, the size of anion ligands, and the congested structure of the complexes.
