Polynorbornene with pentafluorophenyl imide side chain groups: Synthesis and sulfonation

The mixtures of exo‐endo‐monomers and isomerically pure endo‐monomers of N‐pentafluorophenyl‐norbornene‐5,6‐dicarboximide ( 2a ) and N‐phenyl‐norbornene‐5,6‐dicarboximide ( 2b ) were synthesized and polymerized via ring opening metathesis polymerization using bis(tricyclohexylphosphine) benzylidene ruthenium ( IV ) dichloride ( I ) and tricyclohexylphosphine 1,3‐bis(2,4,6‐trimethylphenyl)‐4,5‐dihydroimidazol‐2‐ylidene]benzylidene] ruthenium dichloride ( II ). Ring opening metathesis polymerization of mixtures of exo‐endo‐monomers ( 2a ) and ( 2b ) and pure endo‐ 2b gave the corresponding high molecular weights poly(N‐pentafluorophenyl‐norbornene‐5,6‐dicarboximide) ( 3a ) and poly(N‐phenyl‐norbornene‐5,6‐dicarboximide) ( 3b ). The isomerically pure endo‐ 2a did not polymerize by I in these conditions, since I is the least active catalyst and endo‐ 2a is the least active monomer because of the intramolecular complex formation between the Ru active center and the fluorine atom of ring‐opened endo‐ 2a on the one hand and steric hindrances caused by the pentafluorinated ring on the other. The quantitative hydrogenation of the polymer 3a , at room temperature and 115 bar, was achieved by a Wilkinson's catalyst. The new polynorbornene bearing highly fluorinated sulfonic acid groups (5) was obtained by the reaction of the hydrogenated poly(N‐pentafluorophenyl‐norbornene‐5,6‐dicarboximide) (4) with sodium 4‐hydroxybenzenesulfonate dihydrate. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2925–2933, 2010