Synthesis, characterization, and optical properties of copolymers containing fluorine-substituted distyrylbenzene and nonconjugated spacers

Copolymers containing fluorinated distyrylbenzenes as conjugated segments h ave been synthesized using the Horner-Emmons reaction of dialdehydes and di phosphonates. The presence of well-defined conjugated fluorinated systems g ives rise to strong blue emissions in solution. Quantum yields and emission maxima in solution depend on the substituents on the chromophore and the n ature of the nonconjugated segments. Construction of conjugated Segments co ntaining a central perfluorophenyl ring and aromatic groups substituted wit h electron-donating groups at the terminae, as evidenced by strong solvatoc hromic behavior, allow an induced intramolecular charge transfer state. Fac e-to-face pi stacking has been observed in thin films formed from each of t he polymers and causes large red shifts in the emission as compared to thos e in solution. The low quantum yield of emission in thin films is a result of self-quenching due to stacking.