Synthesis and properties of novel through-space π-conjugated polymers based on poly(p-phenylenevinylene)s having a [2.2]paracyclophane skeleton in the main chain

Palladium-catalyzed polymerization of pseudo-p-divinyl[2.2]paracyclophane (2) and 2,5-dialkoxy-1,4-diiodobenzenes (3a and 3b) was carried out to give the corresponding polymers (4a and 4b) having [2.2]paracyclophane as a repeating unit. The structures of the polymers were supported by H-1 and C-13 NMR spectra. The polymers obtained were soluble in common solvents such as THF, CH2Cl12, CHCl3, toluene, and DMF. Polymer 4a showed an extension of pi-delocalization via the through-space with pi-pi stacking according to the UV-vis absorption spectra in comparison with those of the model compounds 9 and 10. In the fluorescence emission spectrum of 4a in chloroform solution, an intense emission peak was observed at 462 nm (Phi(F) = 0.92) in the visible green region. In the solid state, the absorption spectrum of 4a was very similar to that in solution, while in the emission spectrum of 4a the peak maximum at 507 nm was red-shifted about 45 mn from that in solution. This result indicates that the aggregation or the excimer formation of the polymer would occur in the film state.