Carbocationic Initiation of Polymerization of Vinyl Ethers and N-Vinylcarbazole Induced by (.eta.5-C5Me5)TiMe2(.mu.-Me)B(C6F5)3. The First Examples of Polymerization of This Class of Electron-Rich Olefins by a Metallocene-like Initiator

Addition of Cp * TiMe 3 and B(C 6 F 5 ) 3 (1 :1 ratio ; Cp * = η 5 -pentamethylcyclopentadienyl) to toluene or methylene chloride solutions of N-vinylcarbazole or the vinyl ethers CHR'CHOR (R' = H, R = Me, Et, CH 2 CHMe 2 ; R' = Me, R = Et) and 2,3-dihydrofuran at room temperature or -78 °C results in the formation of polymers which generally exhibit unusually high molecular weights and narrow molecular weight distributions. The materials, which are formed via carbocationic initiation by the titanium-containing cationic complex [(η 5 -C 5 Me 5 )TiMe 2 ] + rather than via Ziegler-Natta processes, are in all cases characterized by GPC and 13 C{ 1 H} and 1 NMR spectroscopy, some by DSC and IR spectroscopy. The neutral borane, B(C 6 F 5 ) 3 , is also a carbocationic polymerization initiator, but is generally less active than the titanium-containing cation.