511512-70-2Relevant articles and documents
Siloxyaluminum alkyl cations: Syntheses, structures, and reactions related to activation of zirconocene catalysts on silica gel surfaces
Wrobel, Olaf,Schaper, Frank,Wieser, Ulrich,Gregorius, Heike,Brintzinger, Hans H.
, p. 1320 - 1325 (2008/10/08)
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)2 ZrCl2, 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(C 6H5)+ the CH-activation product (C5H5)2ZrCH2NMe(C6 H5)+; reaction with Me2Si(ind)2 ZrMe2 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.