Reaction of ether and thioether functionalised 1-alkenes with the cationic permethylzirconocene olefin polymerisation catalyst [(eta(5)-C5Me5)(2)ZrMe](+). Molecular structure of the insertion product [(eta(5)-C5Me5)(2)ZrCH2CH(Me)CH2OEt](+)

摘要

Reaction of [(eta(5)-C5Me5)(2)ZrMe][MeB(C6F5)(3)] (1) with (thio)ether functionalised alkenes: 3-ethoxy-1-propene and 3-(methylthio)-1 propene gives stable insertion products [(eta(5)-C5Me5)(2)ZrCH2CH(Me)CH2XR][MeB(C6F5)(3)] (2: X = 0, R = Et 3. X = S, R = Me) in which the (thio)ether function is intramolecularly coordinated to zirconium. The molecular structure of 2 shows a regular 1-oxa-2-zirconacyclopentane in an envelope conformation. The metallacycles in 2 and 3 are stable toward further insertion of (functionalised) alkenes and cannot be activated for ethene polymerisation by pre-complexation of the (thio)ether function with strong Lewis acids (AlCl3, MgCl2, B(C6F5)(3) or [Ph3C](+)). The strong alkylating co-catalyst Me3Al regenerates complex 1 by exchange of the (thio)ether function for methyl and thus initiates polymerisation of ethene. (C) 1998 Elsevier Science S.A. [References: 26]