Structure and emission spectra of dinuclear lanthanide(III) β-diketonate complexes with a bridging 2,2′-bipyrimidine ligand
2008; Elsevier BV; Volume: 28; Issue: 1 Linguagem: Inglês
10.1016/j.poly.2008.10.019
ISSN1873-3719
AutoresMadelyn H. Baker, Jason D. Dorweiler, Amanda N. Ley, Robert D. Pike, Steven M. Berry,
Tópico(s)Magnetism in coordination complexes
ResumoThe 2,2′-bipyrimidine (bpm) adducts of the β-diketonate complexes of Eu(III), Sm(III), or Yb(III) with 2,2′,6,6′-tetramethyl-2,4-heptanedione (tmhd) resulted in the formation of dinuclear species. The synthesis and X-ray structure of these three new dinuclear lanthanide complexes are found to be similar. Each lanthanide ion is eight coordinate, bound to six O-atoms from the β-diketonates and 2N atoms from the bridging bpm ligand. They exhibit Ln–Ln distances (Sm(III): 6.935 Å, Eu(III): 6.901 Å, Yb(III): 6.679 Å) and Ln–ligand distances that are consistent with the decrease in radii across the lanthanide series. Absorption spectra of the complexes are dominated by ligand absorptions. Both the solution and solid state emission spectra of the complexes resemble ordinary monomeric lanthanide species, indicating independent ions in the dinuclear species. Cyclic voltammetry of all the complexes appear almost identical with discernable ligand centered redox reactions. The complex with Eu(III) ions, having the lowest possible lanthanide redox potential, was not found to display a signal corresponding to metal reduction.
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