G. Ricci, A. Forni, A. Boglia
Jun 19, 2004
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0
Influential Citations
46
Citations
Journal
Organometallics
Abstract
New chromium(II) bidentate phosphine complexes were synthesized by reacting CrCl2(thf) with various bidentate phosphines [bis(dimethylphosphino)methane (dmpm); 1,2-bis(diethylphosphino)ethane (depe); 1,3-bis(diethylphosphino)propane (depp); 1,2-bis(dicyclohexylphpsphino)ethane (dcpe)] in toluene or diethyl ether as solvent. Single crystals of the complex CrCl2(depe)2 were obtained by recrystallization from toluene at low temperature; the structure of the complex was determined by X-ray diffraction and compared with that of the analogous methyl derivative CrCl2(dmpe)2 previously reported by Girolami et al. (dmpe = 1,2-bis(dimethylphosphino)ethane). All the complexes prepared were then used in combination with methylaluminoxane (MAO) for the polymerization of 1,3-butadiene. They were found to be very active catalysts, giving essentially 1,2-polybutadienes having a syndiotactic or isotactic structure depending on the type of phosphine bonded to the chromium atom. The results obtained also have some mechanist...