Siloxyaluminum Alkyl Cations: Syntheses, Structures, and Reactions Related to Activation of Zirconocene Catalysts on Silica Gel Surfaces
Binuclear siloxyaluminum methyl complexes of the type Me2Al(μ-OSiR3)2AlMe2 react with protonated N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate, with release of CH4, to form the dimethylaniline (DMA)-stabilized siloxyaluminum methyl cations Me2Al(μ-OSiR3)2AlMe(NMe2(C6H5)+. These cations abs...
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Veröffentlicht in: | Organometallics 2003-03, Vol.22 (6), p.1320-1325 |
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Hauptverfasser: | , , , , |
Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | Binuclear siloxyaluminum methyl complexes of the type Me2Al(μ-OSiR3)2AlMe2 react with protonated N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate, with release of CH4, to form the dimethylaniline (DMA)-stabilized siloxyaluminum methyl cations Me2Al(μ-OSiR3)2AlMe(NMe2(C6H5)+. These cations abstract a Cl- ligand from (C5H5)2ZrCl2, to give the dinuclear cation {(C5H5)2ZrCl}2(μ-Cl)+, and a CH3 - ligand from (C5H5)2Zr(CH3)2, to give by way of the DMA-stabilized cation (C5H5)2Zr(CH3)NMe2(C6H5)+ the CH-activation product (C5H5)2ZrCH2NMe(C6H5)+; reaction with Me2Si(ind)2ZrMe2 in toluene solution yields a moderately active catalyst for ethene polymerization. This reactivity of siloxyaluminum methyl cations is qualitatively similar to, although substantially lower than, that of a silica gel surface treated with trimethylaluminum and a cationizing agent. |
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ISSN: | 0276-7333 1520-6041 |
DOI: | 10.1021/om0207515 |