POLY(AMMONIUM ALKOXYDICYANOETHENOLATES) AS NEW HYDROPHOBIC AND HIGHLY DIPOLAR POLY(ZWITTERIONS) .1. SYNTHESIS

The nucleophilic ring opening of dicyanoketene ethylene (p = 2) or propylene (p = 3) acetals by tertiary amino monomers readily leads to new crystalline zwitterionic species characterized by the dipolar structure [GRAPHICS] Sixteen monomers were obtained with yields over 70% in the aliphatic (acrylates and methacrylates) or in the heterocyclic (vinylpyridine, N-vinylimidazole) series. Their free-radical polymerization in homogeneous solution in dipolar aprotic solvents (DMF, DMSO) initiated by azobisisobutyronitrile at 60-degrees-C is straightforward. In the methacrylate series, molecular weight may be easily controlled from 5 x 10(6) to 1 x 10(5) by using 2-mercaptoethanol as a transfer agent (C(T) = 0.14). The zwitterionic moiety has been characterized by spectrometry (IR, UV, and C-13 NMR) and by the UV analysis of its protonation in concentrated H2SO4 or HClO4 solutions: [GRAPHICS] pK(a) congruent-to -3.7 according to the Boyd cyanocarbon acidity scale.