We report here on the experimental conditions for radical chlorination that provide improved yields of 2,5-bis(chloromethyl) pyridine and pyrazine, as well as on theoretical calculations which were performed in order to gain some insight regarding the factors that affect reactivity in these systems. The difficulties encountered previously in the methyl functionalization of N-heteroarenes are not due to radical selectivity that produces low yield of the dichlorides or to lower reactivity of this type of compounds, but to the post-halogenation reactions that occur on the desired products. Therefore, a careful handling during and after the reaction allowed us to find conditions for product optimization of α, α -dichlorinated monomers.

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The thermal conversion of dialkylsulfonium polyelectrolyte precursor polymers 1b-e to poly(p-arylene vinylene)s was studied by direct pyrolysis mass spectrometry in order to elucidate the mechanism of the sulfonium elimination reaction. The temperature dependence of the single ion currents of the four more abundant volatile products was correlated with the structural changes introduced in the arylene moiety of the polyelectrolytes and with the counterion nature. Experimental results suggest that the elimination reactions in the solid state proceed through an E2 mechanism.

The polymerizability of nitrogen-containing bissulfonium salts was analyzed. The poor homopolymerization results were attributed to sluggish quinodimethane formation. However, copolymerizations with the non-nitrogenated analogue sulfonium salt were successful. We report here the synthesis and characterization of a series of poly(1,4-phenylene vinylene)-co-(2,5-pyridylene vinylene)s. Elemental analysis, FTIR, UV-vis and fluorescence studies demonstrate that the pyridilene units can be incorporated by the water soluble precursor route in PPV-type polymers with free-standing film formation properties.