Electrosynthesis of electroactive and fluorescent polyphenanthrenes via electropolymerization in BmimPF6

• PDHP and PPhe films by electropolymerization in BmimPF6 were prepared.
• PDHP exhibited better electrochemical and optical properties than PPhe.
• Comparative studies of the PDHP/PPhe obtained in different media were displayed.

Poly(9,10-dihydrophenanthrene) (PDHP) and polyphenanthrene (PPhe) were synthesized electrochemically by direct anodic oxidation of their corresponding monomers in an ionic liquid BmimPF6. The electropolymerization performances of 9,10-dihydrophenanthrene (DHP) and phenanthrene (Phe), together with the properties of both polymers, including electrochemistry, optical properties, thermal degradation, and morphology were comparatively illustrated. FT-IR spectral analysis manifested that the polymerization of DHP occurred primarily at C(2) and C(7) positions, while Phe mainly through the coupling at C(9) and C(10) sites, in good agreement with previous results. Both PDHP (Eg = 2.55 eV) and PPhe (Eg = 2.18 eV) were electroactive and exhibited moderate redox stability, as well as good thermal stability. Furthermore, two polymers could emit yellow–green light, while PDHP showed higher fluorescence quantum yield of 0.14.

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