Metal-Controlled Assembly of Near-Infrared-Emitting Pentanuclear Lanthanide β-Diketone Clusters

Metal-controlled assembly results in a series of lanthanide clusters with the formula of Ln(5)(DBM)(10)(OH)(5)center dot n(solvent) (DBM = dibenzoylmethanido; Ln = Nd (1), Gd (2), Er (3), and Yb (4); solvent = CH3CN or toluene). These pentanuclear clusters with square-pyramidal core structures have been characterized by X-ray diffraction analysis. Clusters 1, 3, and 4 show typical near-infrared (NIR) luminescence upon excitation at 350 nm, which represents the first examples of pentanuclear lanthanide clusters with sensitized NIR emission.