- Die Reaktion des Tri(isobutyl)alans mit Kalium-eine Neuuntersuchung; Kristallstruktur des Kalium
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The synthesis of hexa(isobutyl)dialanate with an aluminium-aluminium bond from tri(isobutyl)alane and potassium is described in the literature.We have repeated this reaction under the conditions given, but have not been able to trace the dialanate.Instead
- Uhl, Werner,Wagner, Juergen
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- Structural characterization of Al10O6 iBu16(μ-H)2, a high aluminum content cluster: Further studies of methylaluminoxane (MAO) and related aluminum complexes
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The first structurally characterized isobutyl-containing aluminoxane compound is presented. The Al10O6iBu 16(μ-H)2 (I) cluster is produced from neat octakis-isobutyltetraluminoxane (Al4O2iBu 8) at 80°C in 6-8 h followed by slow crystallization. The crystal is triclinic (space group P1) with the molecule lying on an inversion center. This aluminoxane contains both nearly linear, 154(2)°, aluminum-bridging hydrides and three-coordinate aluminum sites. Solid-state 27Al magic-angle spinning (MAS) NMR experiments were done at 19.6 and 40 T (833 MHz and 1.703 GHz, 1H) and at 30-35 kHz spinning speeds, leading to the determination of the Cq and η values for the two four-coordinate Al sites and a lower limit of Cq for the three-coordinate Al site. Geometry-optimized restricted Hartree-Fock calculations at the double-ζ level of an idealized structure (methyl substituted, D2h geometry) yielded Cq and η in close agreement with experiment; C q agrees within 3 MHz.
- Wu, Feng-Jung,Simeral, Larry S.,Mrse, Anthony A.,Eilertsen, Jan L.,Negureanu, Lacramioara,Gan, Zhehong,Fronczek, Frank R.,Hall, Randall W.,Butler, Leslie G.
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- General copper-catalyzed coupling of alkyl-, aryl-, and alkynylaluminum reagents with organohalides
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We report the first example of a very general Cu-catalyzed cross-coupling of organoaluminum reagents with organohalides. The reactions proceed for the couplings of alkyl-, aryl-, and alkynylaluminum reagents with aryl and heteroaryl halides and vinyl bromides, affording the cross-coupled products in good to excellent yields. Both primary and secondary alkylaluminum reagents can be utilized as organometallic coupling partners. These reactions are not complicated by β-hydride elimination, and as a result rearranged products are not observed with secondary alkylaluminum reagents even for couplings with heteroaryl halides under "ligand-free" conditions. Radical clock experiment with a radical probe and relative reactivity study of Ph3Al with two haloarenes, 1-bromonaphthalene and 4-chlorobenzonitrile, having two different redox potentials indicates that the reaction does not involve free aryl radicals and radical anions as intermediates. These results combined with the result of the Hammett plot obtained by reacting Ph3Al with iodoarenes containing p-H, p-Me, p-F, and p-CF3 substituents, which shows a linear curve (R2 = 0.99) with a ρ value of +1.06, suggest that the current transformation follows an oxidative addition-reductive elimination pathway.
- Shrestha, Bijay,Thapa, Surendra,Gurung, Santosh K.,Pike, Ryan A. S.,Giri, Ramesh
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p. 787 - 802
(2016/02/18)
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- Transition metal compound having indenyl-containing metallocene
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The novel transition metal compound of the invention is represented by the following formula (I): STR1 wherein M is a transition metal; R1 is a hydrocarbon group of 2 to 6 carbon atoms, R2 is an aryl group of 6 to 16 carbon atoms; X1 and X2 are each a halogen atom or the like; and Y is a divalent hydrocarbon group, a divalent silicon-containing group or the like. An olefin polymerization catalyst component of the present invention comprises the aforementioned transition metal compound.
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- Polymerization of olefins in the presence of a supported catalyst
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A supported catalyst component for an olefin polymerization catalyst comprising a solid particulate support, a magnesium halide, and optionally a Group 4 or 5 transition metal compound, a Group 2 or 13 organometal compound, and an electron donor, wherein a majority of particles of the solid particulate support is in the form of an agglomerate of subparticles. A process for preparing this supported catalyst component. A catalyst composition comprising this catalyst component and a cocatalyst. An olefin polymerization process using such a catalyst composition.
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