Synthesis and Characterization of the Europium(III) Pentakis(picrate) Complexes with Imidazolium Countercations: Structural and Photoluminescence Study

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• 作者：Alex S. Borges ; Jos茅 Diogo L. Dutra ; Ricardo O. Freire ; Renaldo T. Moura ; Jr. ; Jeferson G. Da Silva ; Oscar L. Malta ; Maria Helena Araujo ; Hermi F. Brito
• 刊名：Inorganic Chemistry
• 出版年：2012
• 出版时间：December 3, 2012
• 年：2012
• 卷：51
• 期：23
• 页码：12867-12878
• 全文大小：585K
• 年卷期：v.51,no.23(December 3, 2012)
• ISSN：1520-510X

文摘

Six new lanthanide complexes of stoichiometric formula (C)₂[Ln(Pic)₅]鈥攚here (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鈥攈ave 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鈥?/sup> 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.}