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Diastereoselective Insertion of Isocyanide into the Alkyl−Metal Bond of Methylbenz[ e ]indenyl ansa ‐Zirconocene Complexes
Author(s) -
Sebastián Alfredo,
Royo Pascual,
GómezSal Pilar,
Ramírez de Arellano Carmen
Publication year - 2004
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.200400333
Subject(s) - chemistry , isocyanide , alkylation , alkyl , metal , medicinal chemistry , nuclear magnetic resonance spectroscopy , polymerization , stereochemistry , ethylene , catalysis , polymer chemistry , organic chemistry , polymer
Alkylation of ansa ‐zirconocene [Zr{(η 5 ‐C 5 H 5 )SiMe 2 (MBI)}Cl 2 ] (MBI = η 5 ‐2‐Me−C 13 H 7 ) with MgRCl gave the dimethyl complex [Zr{(η 5 ‐C 5 H 5 )SiMe 2 (MBI)}Me 2 ], but unresolvable mixtures containing mono‐alkylated compounds were obtained when bulkier alkyls were used. However pure dialkyl complexes [Zr{(η 5 ‐C 5 H 5 )SiMe 2 (MBI)}R 2 ] (R = CH 2 Ph, CH 2 SiMe 3 ) were easily obtained using K(CH 2 Ph) and Li(CH 2 SiMe 3 ) as alkylating agents. Diastereoselective insertion into the MBI‐unprotected Zr−R bond was observed when all of these dialkyl complexes were treated with 2,6‐xylyl isocyanide to give the iminoacyl compounds [Zr{(η 5 ‐C 5 H 5 )SiMe 2 (MBI)}R{CR[η 2 ‐ N‐ (2,6‐xylyl)]}] (R = Me, CH 2 Ph, CH 2 SiMe 3 ). All of the new complexes were characterized by NMR spectroscopy and the X‐ray molecular structures of the dibenzyl and the imino‐benzyl compounds were determined. The catalytic activity for ethene polymerization and ethene/1‐hexene copolymerization of the dichloro zirconocenes [Zr{(η 5 ‐C 5 H 5 )EMe 2 (MBI)}Cl 2 ] (E = C, Si), activated with methylalumoxane (MAO), was measured. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)