Quenching of the long-lived Ru(II) bathophenanthroline luminescence for the detection of supramolecular interactions

A feasibility study based on tailor-made peptide sequences for a new robust luminescence probe-system using the long-lived luminescence of a Ru(II)-bathophenanthroline complex in combination with an efficient anthraquinone-type quencher is presented. Due do their high chemical stability, both dyes can be introduced during solid-phase peptide synthesis avoiding post-synthetic labelling. Photophysical measurements revealed an intense quenching of the luminescence of the Ru-complex (65-68%) which was also confirmed by calculations resulting from decay time measurements. The long-lived luminescence allows for a time-gated detection scheme, which can reduce any luminescence contribution from matrix components.