New hetero-dilanthanide complexes containing Ln1(fod)3 and Ln2(fod)3 fragments (Ln=Pr-Nd; Nd-Sm; Eu-Tb and Ho-Er) linked by bis-diimine bridging ligand

New hetero-dilanthanide beta-diketonate complexes of the type [Ln(1)Ln(2)(fod)(6)(mu-bpm)] (fod is the anion of 6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedione; bpm = 2,2'-bipyrimidine; Ln(1) = Pr and Ln(2) = Nd (1); Ln(1) = Nd and Ln(2) = Sm (2); Ln(1) = Eu and Ln(2) = Tb (3) and Ln(1) = Ho and Ln(2) = Er (4)) have been isolated by reacting sequentially, the coordinatively unsaturated Ln(fod)(3) chelates of two different lanthanides and 2,2'-bipyrimidine bridging ligand in 1:1:1 molar ratio, in ethanol. The purity and hetero-dilanthanide nature of the complexes has been confirmed by NMR, 4f-4f absorption spectroscopies and electrospray mass spectrometry. The oscillator strength of the hypersensitive transitions confirms the presence of the two different lanthanides in the complexes in 1:1 ratio. The complexes 2 and 3 display strong pink and red luminescences, respectively. The intramolecular Tb(III) -> Eu(III) energy transfer has been observed in complex 3. (C) 2010 Elsevier B.V. All rights reserved.