Fluorescence and electrochemical properties of naphthylporphyrins and porphyrin–anthraquinone dyads

Porphyrins bearing naphthyl group were synthesized to afford expanded π-conjugated systems and were characterized by 1H NMR, IR, FAB-MS and UV–vis spectra. The fluorescence spectra illustrate that the maximal excitation and emission wavelengths of naphthylporphyrins were red shifted with 3–6 nm compared with that of H2TPP. The cyclic voltammetric results of 8 kinds of naphthylporphyrin are firstly reported. Several porphyrin–anthraquinone dyads were synthesized and their molecular energy levels were obtained from the multilevel ionization potential (IP) and electron affinity (EA) according to the redox potential. Photoinduced intramolecular electron transfer occurred from porphyrin ring to anthraquinone moiety, which was confirmed by fluorescence quenching and molecular energy level changing.