Blue-emitting soluble poly(m-phenylenevinylene) derivatives

Soluble poly(m-phenylenevinylene) derivatives (4) were synthesized via Witt ig-Horner reaction. The number-average degree of polymerization was estimat ed to be around 25-35. On the basis of FT-IR and H-1 NMR spectra, the olefi ns in the polymers were confirmed to be predominantly in the trans-configur ation. A model compound, 3,5-distyryl-4-hexyloxytoluene (5), was also synth esized to aid the structural characterization. Comparison of photoabsorptio n and emission characteristics between 4 and 5 indicated that the m-phenyle ne effectively interrupted the conjugation, allowing predictable color cont rol in the pi -conjugated polymers. At low temperature, the fluorescence of 4 was readily resolved into two peaks, suggesting the predominant emission s were from 0-1 and 0-2 transitions. Polymers 4 were found to be highly lum inescent in both solution and film states. LED devices using 4 gave blue EL output (emission lambda (max) at 445 and 462 nm).