Carbon copolymerization with olefins

Palladium(II) complexes possessing bidentate ligands are known to efficiently catalyze the copolymerization of olefins with carbon monoxide to form polyketones.594-596 Sulfur dioxide is an attractive monomer for catalytic copolymerizations with olefins since S02, like CO, is known to undergo facile insertion reactions into a variety of transition metal-alkyl bonds. Indeed, Drent has patented alternating copolymerization of ethylene with S02 using various palladium(II) complexes.597 In 1998, Sen and coworkers also reported that [(dppp)PdMe(NCMe)]BF4 was an effective catalyst for the copolymerization of S02 with ethylene, propylene, and cyclopentene.598 There is a report of the insertion reactions of S02 into PdII-methyl bonds and the attempted spectroscopic detection of the copolymerization of ethylene and S02.599... 

Drent, E., van Broekhoven, J. A. M., Doyle, M. J. and Wong, P. K., Palladium Catalyzed Copolymerization of Carbon Monoxide with Olefins to Alternating Polyketones and Polyspiroketals , in Ziegler Catalysts, Springer-Verlag, Berlin, 1995, pp. 481 196. 

Semiyen, J. A. Ring-Chain Equilibria and the Conformations of Polymer Chains. Vol. 21, pp. 41-75. Sen, A. The Copolymerization of Carbon Monoxide with Olefins. Vol. Tip4, pp. 125-144. 

Drent, E. vanBroekhoven, J.A.M. Doyle, M. J. Efficient palladium catalysts for the copolymerization of carbon monoxide with olefins to produce perfectly alternating polyketones. J. Organomet. Chem. 1991,477,235-251. 

Batistini, A. Consiglio, G Mechanistic aspects of the alternating copolymerization of carbon monoxide with olefins catalyzed by cationic palladium complexes. Organometallics 1992,11,1766-1769. 

Sen, A. and Lai, T.W. (1982) Novel palladium(II) catalyzed copolymerization of carbon monoxide with olefins. Journal of the American Chemical Society, 104, 3520 Lai, T.W. and Sen, A. (1984) Palladium(ll)-catalyzed copolymerization of carbon monoxide with ethylene. Direct evidence for a single mode of chain growth. Organomctallics, 3, 866. 

Fig. 2. Dependence of olefin reactivity on its carbon atom number when linear a-olefins are copolymerized with ethylene.

It has been shown by Barb and by Dainton and Ivin that a 1 1 complex formed from the unsaturated monomer (n-butene or styrene) and sulfur dioxide, and not the latter alone, figures as the comonomer reactant in vinyl monomer-sulfur dioxide polymerizations. Thus the copolymer composition may be interpreted by assuming that this complex copolymerizes with the olefin, or unsaturated monomer. The copolymerization of ethylene and carbon monoxide may similarly involve a 1 1 complex (Barb, 1953). 

Water-soluble dicationic palladium(II) complexes [(R.2P(CH2)3PR.2)Pd-(NCMe)2][BF4]2 proved to be highly active in the carbon monox-ide/ethene copolymerization under biphasic conditions (water-toluene). In the presence of an emulsifier and methanol as activator, the catalytic activity increased by a factor of about three. Also higher olefins could be successfully incorporated into the copolymerization with CO and the terpolymerization with ethene and CO.184... 

In addition to a-olefins, p-/-butylstyrene can be used as a comonomer for the isotactic specific copolymerization with carbon monoxide with chiral induction [32], Whereas bipyridyl as ligand gives a syndiotactic polymer, the Pd-catalyzed polymerization with ligand 11 leads to a polymer with isotacticity of over 98% and high optical activity ([ ]D -536° (in CH2C12)) [33, 34]. The BINAPHOS catalyst described above is also effective in this type of copolymerization [25],... 

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