Upconversion in a d-f [RuYb3] Supramolecular Assembly

ABSTRACT: We have prepared a hetero-tetrametallic assembly consisting of three ytterbium ions coordinated to a central [Ru(bpm)3]2+ (bpm = 2,2 '-bipyrimidine) motif. Irradiation into the absorption band of the peripheral ytterbium ions at 980 nm engenders emission of the 3MLCT state of the central [Ru(bpm)3]2+ core at 636 nm, which represents the first example of f reveal a slow rise of the UC emission, which was modeled with a mathematical treatment of the observed kinetics according to a cooperative photosensitization mechanism using a virtual Yb centered doubly excited state followed by energy transfer to the Ru centered 1MLCT state.