Electrochemical polymerization of phenanthrene in mixed electrolytes of boron trifluoride diethyl etherate and concentrated sulfuric acid

A novel high-quality polyphenanthrene (PPH) film with electrical conductivity of 10(-1) S cm(-1) was synthesized electrochemically by direct anodic oxidation of phenanthrene in boron trifluoride diethyl etherate containing 10% concentrated sulfuric acid (v/v). The oxidation onset potential of phenanthrene in this medium was measured to be only 0.91 V versus saturated calomel electrode (SCE), which was lower than that determined in acetonitrile +0.1 mol L-1 Bu4NBF4 (1.56 V versus SCE). As-formed PPH films from this medium showed good electrochemical behavior and stability. De-doped PPH films were thoroughly soluble in dimethylsulfoxide or CHCl3. The structure and morphology of the polymer were investigated using UV-visible and Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy. FTIR and H-1 NMR spectra showed that the PPH was grown via the coupling of the monomer mainly at the C-4, C-5, C-9 and C-10 positions. Fluorescence spectral studies indicated that PPH was a blue-green light emitter. (c) 2007 Society of Chemical Industry.