28923-39-9Relevant articles and documents
Molybdenum and nickel atrane complexes with a rigid tripodal tetraphosphine ligand incorporating imidazole rings
Gendy, Chris,Spasyuk, Denis,Harrison, Alexander,Roesler, Roland
, p. 150 - 154 (2018)
Tripodal, tetradentate tetraphosphine ligand tris(1H-2-diisopropylphosphinoimidazol-1-yl)phosphine (1) was synthesized in three straightforward steps from widely available starting materials. The ligand crystallized in a C3-like conformation suitable for metal coordination. Nickel(II) complex 2 was prepared from 1 and Ni(dme)Br2 and adopted a classical atrane structure with trigonal pyramidal geometry at the metal, a bromide covalently bonded in the axial position, and a bromide ion in the outer coordination sphere. Molybdenum(III) complex 3 was prepared from 1 and MoCl3(thf)3 and could be structurally characterized using a co-crystal with Cp2Co and [Cp2Co]Cl. It displayed a face-capped octahedral geometry at the seven-coordinated metal. Complexes 2 and 3 proved prone to decomposition under reductive and oxidative conditions, hindering the investigation of their chemistry. Crystallization attempts from acetonitrile led to the isolation of dinuclear hydrolysis product 4, with the Mo(III) centres bridged by two chlorides and two 2-(diisopropylphosphino)imidazole moieties in a paddlewheel arrangement.
Iron and nickel complexes containing β-diketiminato ligands with thioether tethers
Pfirrmann, Stefan,Limberg, Christian,Hoppe, Elke
, p. 312 - 316 (2009)
A novel β-diketiminato ligand precursor, LH (II), containing thioether tethers was synthesized by the reaction of acetylacetone and 2-methylthioaniline. II was deprotonated and used in the synthesis of two iron(II) complexes, [LFeCl] (1), and [LFeOTf] (2)
Simple and Strong Dative Attachment of α-Diimine Nickel (II) Catalysts on Supports for Ethylene Polymerization with Controlled Morphology
Kianfar, Ehsan,Azimikia, Reza,Faghih, Seyed Mohammad
, p. 2322 - 2330 (2020/02/25)
Abstract: In this article, preparation of novel spherical MgCl2 supported α-diimine nickel (II) catalysts for ethylene polymerization in slurry phase is reported. α-Diimine ligands were synthesized by condensation reaction of 2, 6-disubstituted alkyls or aryls anilines and Ace naphthoquinone Which have hydroxyl functionality in their para-position. Hydroxyl functionalized α-diimine attached strongly on to the spherical MgCl2 support surface by dative bonding. No linker was needed to attach the complexes onto the support surface and the amount of loaded Nickel was controllable to improve morphology and especially bulk density of polymer powder. A significant reduction in catalysts activity has happened when homogeneous catalysts were supported onto silica but this reduction was decreased when they were supported onto thermally treated spherical MgCl2. As homogeneous bis(N,N′-(4-(3-hydroxyl-propyl)-2,6-di[(4-tert-butyl-phenyl)-phenyl) amino] Ace naphthoquinone Nickel dibromide(d) showed the highest activity among other evaluated homogeneous catalysts, its MgCl2 supported catalyst (d/S-MgCl2) has shown the highest activity among MgCl2 supported catalysts too. These MgCl2 supported catalysts were pre-polymerized in presence of ethylene monomer in the mild polymerization condition to yield a pre-polymerized catalyst with polymer/catalyst weight ratio equal to six. Ethylene polymerization was carried out to make spherical particles of polyethylene without reactor fouling by these pre-polymerized catalysts. Clearly, it is shown in SEM images that the spherical morphology of MgCl2 support is replicated in the produced polymer. The molecular weight and molecular weight distribution of produced polymer with MgCl2 supported catalysts were higher than those produced by homogeneous catalysts. Graphic Abstract: α–Diimine nickel (II) complexes have hydroxy functionality where produce strong dative bonding onto spherical MgCl2. This bonding is strong enough that these catalysts are suitable for slurry polymerization of ethylene without reactor fouling due to catalyst leaching from support. The chemical structure of MgCl2 leads to high active supported catalysts. The molecular weight and polydispersity index of produced polymrers using these supported catalysts are higher than those produced by equivalent homogeneous catalysts and are controllable by selection of appropriate ligand for used α–diimine nickel (II) complex or hydrogen concentration in ethylene polymerization.[Figure not available: see fulltext.].
