Artículos de revistas
Synthesis and Characterization of the Europium(III) Pentakis(picrate) Complexes with Imidazolium Countercations: Structural and Photoluminescence Study
Fecha
2012Registro en:
INORGANIC CHEMISTRY, WASHINGTON, v. 51, n. 23, pp. 12867-12878, DEC 3, 2012
0020-1669
10.1021/ic301776n
Autor
Borges, Alex S.
Dutra, Jose Diogo L.
Freire, Ricardo O.
Moura Jr., Renaldo T.
Silva, Jeferson G. Da
Malta, Oscar L.
Araujo, Helena Maria dos Reis P de
Brito, Hermi Felinto de
Institución
Resumen
Six new lanthanide complexes of stoichiometric formula (C)(2)[Ln(Pic)(5)]-where (C) is a imidazolium cation coming from the ionic liquids 1-butyl-3-methylimidazolium picrate (BMIm-Pic), 1-butyl-3-ethylimidazolium picrate (BEIm-Pic), and 1,3-dibutylimidazolium picrate (BBIm-Pic), and Ln is Eu(III) or Gd(III) ions-have been prepared and characterized. To the best of our knowledge, these are the first cases of Ln(III) pentakis(picrate) complexes. The crystal structures of (BEIm)(2)[Eu(Pic)(5)] and (BBIm)(2)[Eu(Pic)(5)] compounds were determined by single-crystal X-ray diffraction. The [Eu(Pic)(5)](2-) polyhedra have nine oxygen atoms coordinated to the Eu(III) ion, four oxygen atoms from bidentate picrate, and one oxygen atom from monodentate picrate. The structures of the Eu complexes were also calculated using the sparkle model for lanthanide complexes, allowing an analysis of intramolecular energy transfer processes in the coordination compounds. The photoluminescence properties of the Eu(III) complexes were then studied experimentally and theoretically, leading to a rationalization of their emission quantum yields.