Upconversion in a d–f [RuYb 3 ] Supramolecular Assembly
Résumé
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 3 MLCT state of the central [Ru(bpm)3] 2+ core at 636 nm, which represents the first example of f→d molecular upconversion (UC). Time-resolved measurements reveal a slow rise of the UC emission, which was modeled with a mathematic 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 1 MLCT state.
Domaines
Chimie
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