93530-27-9Relevant academic research and scientific papers
Bimetallic halides. Crystal structure of and ethylene polymerization by VCl2·ZnCl2·4THF
Smith, Paul D.,Martin, Joel L.,Huffman, John C.,Bansemer, Rick L.,Caulton, Kenneth G.
, p. 2997 - 3002 (2008/10/08)
The title compound is prepared either by the zinc reduction of VCl4(THF)2 in refluxing THF or by the reaction of [V2(μ-Cl)3-(THF)6]2Zn 2Cl6 with ZnCl2(THF)2 in THF at 90°C. The crystal structure indicates discrete molecules of (THF)4V(μ-Cl)2ZnCl2. The six-coordinate environment of vanadium approximates octahedral geometry whereas the four-coordinate zinc geometry is virtually tetrahedral. The octahedron and tetrahedron are linked by two chloride bridges. Crystals belong to the monoclinic space group P21/c with cell dimensions (-158°C) a = 14.732 (5) A?, b = 9.680 (3) A?, c = 16.207 (6) A?, and β = 94.12 (2)° and Z = 4. High catalytic activity was found for ethylene polymerization by the title compound as well as for several other related V/Zn/Cl/THF compounds whose structures have been established. Catalyst activity is greatly enhanced by added halocarbons. Activity of V(II) compounds equals or exceeds that of V(III) compounds, which tends to deny a previous suggestion that the halocarbon functions to keep vanadium in oxidation state +3. Moreover, the V(II) compounds fail to be oxidized to V(III) even by neat CH2Cl2.
