Facile protonation of β,β'-fused porphycene <i>via</i> π-π stacking interactions

Protonation studies were conducted on [Formula: see text],[Formula: see text]'-fused 2,7,12,17-tetraisopropyldinaphthoporphycene and 2,3,6,7,12,13,16,17-octaethylporphycene with trifluoroacetic acid and pentafluorobenzoic acid. The weaker pentafluorobenzoic acid was able to form a stable diprotonated species with dinaphthoporphycene only in the solid state, owing to the [Formula: see text]-[Formula: see text] stacking interactions.