Synthesis and spectral properties of perylene-rhodamine dyads with lipophilic dendritic auxiliaries

The present publication reports a new entry of perylene-rhodamine dyads, whose solubilities in organic solvents are enhanced by the lipophilic dendritic auxiliaries. Spectroscopic studies on these dyad systems have demonstrated that the intramolecular Förster resonance energy transfer (FRET) from the perylene donor to the rhodamine acceptor was activated upon protonation with either H2SO4 or TFA to result in drastic colour change of the fluorescence emissions. This phenomenon can be reasonably accounted for in terms of the switching behaviour of the FRET interactions, which is suppressed by disruptive interference from lone pair electrons of the amino moieties.