文摘
The polymerization of styrene in the presence of various anisole derivatives has been examined by using the half-sandwich scandium diaminobenzyl complex (C5Me4SiMe3)Sc(CH2C6H4NMe2-o)2 with borate [Ph3C][B(C6F5)4]. The syndiospecific chain transfer polymerization of styrene proceeded efficiently via the ortho-C–H bond activation of anisoles, affording the corresponding end-ortho-anisyl-functionalized syndiotactic polystyrenes. The molecular weight of the resulting polymers could be controlled in a wide range by changing the styrene/anisole feeding ratio. Propenyl and halogen (F, Cl, Br, and I) substituents on the anisole compounds are compatible with the present catalyst system, thus enabling easy introduction of unsaturated C═C double bond or halogen moieties together with the anisole functionality to the chain end of syndiotactic polystyrene.