Polyethylenes, phosphine-terminated

Recently, diphenylphosphine has been shown to be an efficient chain-transfer agent in organolanthanide-catalyzed ethylene polymerization, yielding phosphine-terminated polyethylenes. This reaction is a versatile, efficient way of incorporating an electron-rich functional group into an otherwise inert polymer.929... 

Phosphine-terminated polyethylenes have been prepared in related organolanthanide-catalyzed reactions [31, 32]. After initiation by insertion of ethylene into the Ln-P bond of a phosphide complex, polymerization occurs by repeated ethylene insertion. Termination results from protonolysis of the growing polymer chain via a four-centered a-bond metathesis transition state, as seen in Scheme 19, to give a polymeryl-phosphine and regenerate the lanthanum phosphide complex (Scheme 20). 

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