Polynorbornene with pentafluorophenyl imide side chain groups: Synthesis and sulfonation

摘要

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 fluo rine 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.