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Radical Polymerization of Vinyl Acetate with Bis(tetramethylheptadionato)cobalt(II): Coexistence of Three Different Mechanisms |
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| Authors: | K. S. Santhosh Kumar Dr. Yves Gnanou Dr. Yohan Champouret Dr. Jean‐Claude Daran Dr. Rinaldo Poli Prof. |
| Affiliation: | 1. Laboratoire de Chimie des Polymères Organiques, ENSCPB‐CNRS‐Université Bordeaux, 1, 16, Avenue Pey Berland, 33607 Pessac Cedex (France), Fax: (+33)?561553003;2. CNRS;3. LCC (Laboratoire de Chimie de Coordination), Université de Toulouse;4. UPS, INPT, 205, route de Narbonne, 31077 Toulouse (France), Fax: (+33)?561553003;5. Institut Universitaire de France, 103 bd Saint‐Michel, 75005 Paris (France) |
| Abstract: | Poly(vinyl acetate) by OMRP : Increasing the steric encumbrance of the β‐diketonate R substituents in vinyl acetate (VAc) polymerization mediator [Co{OC(R)CHC(R)O}2] from Me to tBu sufficiently weakens the CoIII? PVAc bond of the polymer chain to allow it to operate by both associative (degenerative transfer) and dissociative (organometallic radical polymerization, OMRP) mechanisms (see scheme). The CoIII? PVAc species also acts as a transfer agent in the absence of Lewis bases, whereas the CoII complex shows catalytic chain transfer (CCT) activity.  |
| Keywords: | cobalt density functional calculations polymerization radical reactions reaction mechanisms |