Raman spectra of poly(2-pyridinium hydrochloride-2-pyridylacetylene)

Poly(2-pyridinium hydrochloride-2-pyridylacetylene) (P2EPH) is a water-soluble conjugated polymer that is fluorescent when excited in the visible region. The problems associated with this fluorescence have been overcome, thus permitting a Raman spectroscopic investigation of P2EPH. The fluorescence was avoided by recording spectra with excitation in the UV region (244 nm); for spectra excited with a visible laser, silver colloids, electrodes and pellets were used to minimize the fluorescent background. The obtained results allowed an improvement in the band assignment of the P2EPH vibrational spectra and strongly suggested a higher content of the non-protonated pyridine moiety than previously reported.