Water-soluble ruthenium complex-pyrene dyads with extended triplet lifetimes for efficient energy transfer applications
Arne C. Sell, Julius C. Wetzel, Matthias Schmitz, A. Wouter Maijenburg, Georg Woltersdorf, Robert Naumann, Christoph Kerzig
Abstract
the Dexter mechanism is slower by a factor of two when bipyridine co-ligands are employed, which is rationalized by a poor orbital overlap. Both dyads are very efficient sensitizers for the formation of singlet oxygen in air-saturated water as well as for the bimolecular generation of anthracene triplets that are key intermediates in upconversion mechanisms. This is demonstrated by the 5-hydroxymethylfurfural oxidation, which yields completely different main products depending on the pH value of the aqueous solution, as an initial application-related experiment and by time-resolved spectroscopy. Our findings are important in the greater contexts of photocatalysis and energy conversion in the "green" solvent water.