Equimolecular binary polydienes II. Cobalt catalysts for the preparation of equibinary polyisoprenes

In the course of an investigation of isoprene stereospecific polymerization, complex cobalt catalysts were found to yield in a broad range of experimental conditions polymers with an unusual equimolar binary microstructure, i.e. poly (cis 1.4–3.4) isoprene. In the presence of hexamethylphosphoramide similar catalysts yield another type of nearly equibinary See p. 78, 3rd identation. polyisoprene i.e. poly (1.2–3.4) isoprene. A possible stereospecific propagation mechanism is suggested.