173772-80-0Relevant academic research and scientific papers
A counterintuitive, yet efficient synthesis of bis(indenyl)zirconium dihalides
Balboni, Davide,Camurati, Isabella,Ingurgio, Antonio Cascio,Guidotti, Simona,Focante, Francesca,Resconi, Luigi
, p. 2 - 10 (2003)
The use of bisindenyl zirconium dimethyl in the synthesis of the corresponding dihalides is described. The synthesis of Ind2 ZrCl2 has been carried out, cleanly and quantitatively, by chlorination of Ind2ZrMe2 (2) with a variety of inorganic chlorides, including BCl3, SCl2 in either toluene or methylene chloride, and HCl in Et2O. The latter method is the preferred one, since it produces methane as the only byproduct, and the formed Ind2ZrCl2 precipitates quantitatively from the Et2O solvent: a simple filtration then gives the analytically pure product in quantitative yield. Ind2ZrBr2 and Ind2ZrI2 are obtained by reacting 2 with Br2 and I2, respectively. The 'inverse' synthesis of metallocene dichlorides by chlorination of their dimethyl 'derivatives' has advantages compared to the classic method: first, Ind2ZrCl2 is obtained in higher yield (90-96%); second, it is easier to purify (at the dimethyl stage) and is obtained free from LiCl. Five bisindenyl zirconium complexes with different sigma ligands have been investigated in solution propylene polymerizations: it is found that the σ-ligands have no relevant influence on the catalyst activity, nor on the polymer properties.
Selective halodemethylation reactions of metallocene dimethyls with triphenylmethyl chloride and benzyl bromide
Hawrelak, Eric J.,Deck, Paul A.
, p. 9 - 11 (2008/10/09)
NMR-scale reactions of several group 4 metallocene dimethyls with either trityl chloride or benzyl bromide gave the corresponding L2M(Me)X complexes selectively. Five reactions, including syntheses of Cp2-Zr(Me)Cl and Ind2Zr(Me)Cl, were conducted on a preparative scale to afford useful isolated yields of L2M-(Me)Cl complexes.
