Synthesis of Poly(1,4-naphthylenevinylenes):  Metathesis Polymerization of Benzobarrelenes

Abstract

The syntheses of hexyl- and undecyl-substituted benzobarrelenes 10a,b are described. These molecules readily undergo ring-opening metathesis polymerization (ROMP) to generate the corresponding ring-opened polymers 11a,b. Polymers 11a,b can be conveniently converted into alkyl-substituted poly(1,4-naphthylenevinylenes) (PNVs), 13a,b, by oxidizing them using DDQ (2,3-dichloro-5,6-dicyanoquinone). Both 13a and 13b are soluble in organic solvents and are shown by NMR and UV/vis spectroscopy to be fully conjugated. Strong fluorescence is observed for these new materials. Thin films can be prepared by spin-coating chloroform solutions of the conjugated polymers on glass slides. After being doped with an acetonitrile solution of nitrosonium tetrafluoroborate, these polymer films become highly conductive. The conductivities of 13a,b, 6 and 15 S cm^(-1), respectively, are over 2 orders of magnitude higher than that of the insoluble PNV previously prepared by a different precursor route.

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