Fluorescence Enhancement by Electron-Withdrawing Groups on .BETA.-Diketones in Eu(III)-.BETA.-diketonato-topo Ternary Complexes.

• YUAN Jingli

  Department of Chemistry, Waseda University

• MATSUMOTO Kazuko

  Department of Chemistry, Waseda University

Bibliographic Information

Other Title

• Fluorescence Enhancement by Electron-Withdrawing Groups on ß-Diketones in Eu(III)-ß-diketonato-topo Ternary Complexes

Abstract

Europium(III) complexes with two series of β-diketonates and trioctylphosphine oxide (topo) have been synthesized and the fluorescence properties were studied. The β-dikatonate ligands used had the formula R₁COCHCOR₂ (I: R₁=2- naphthyl, R₂=CF₃, CF₂CF₃, CF₂CF₂CF₃, CF₂CF₂CF₂CF₃; II: R₁=2-phenanthryl, R₂=CF₃, CF₂CF₃, CF₂CF₂CF₃, CF₂CF₂CF₂CF₃, which are designated as NF₃, NF₅, NF₇, NF₉, PF₃, PF₅, PF₇ and PF₉, respectively). These complexes having the composition of [Eu(L)₃(topo)₂] (L=NF₃-NF₉, PF₃) and [Eu(L) ₃(topo)_1.5] (L=PF₅-PF₉) gave very strong fluorescence emission when excited by UV light (complexes of NF₃-NF₉, λ_{ex, max}=339nm, λ_{em, max}=615nm, PF₃, λ_{ex, max}=344nm, λ_{em, max}=615nm, PF₅-PF₉, λ_{ex, max}=346nm, λ_{em, max}=615nm). The ultra-violet spectra, fluorescence spectra, molar absorption coefficient (ε), fluorescence quantum yield (φ_f), and fluorescence lifetime (τ) of the complexes in benzene were measured. The results reveal tendencies for φ_f and the fluorescence absolute sensitivity (A.S=εφ_f) in the following order: φ_f, 2-naphthyl>2-phenanthryl(for an identical R₂); C₄F₉≥C₃F₇>C₂F₅>CF₃(for an identical R₁); A.S, PF₉>PF₇>NF₉≈NF₇>PF₅≈NF₅>NF₃>PF₃. The ¹H NMR signal of β-H in the β-diketonate ligand turns out to be a good measure to estimate φ_f; since the R₂ is more electron-withdrawing, the β-H chemical shift goes to a higher field and the fluorescence of the complex becomes more enhanced. The detection limit of the complex [Eu(L)₃(topo)_1.5] (L=PF₇) is 4.42×10^-12M (M=mol dm^-3).

Journal

• Analytical Sciences

  Analytical Sciences 12 (1), 31-36, 1996

  The Japan Society for Analytical Chemistry

Keywords

• Europium complex
• fluorophotometry
• β-diketone
• trioctylphosphine oxide

Details

• CRID: 1390282679229564544
• NII Article ID: 10002407334
• NII Book ID: AA10500785
• DOI: 10.2116/analsci.12.31
• COI: 1:CAS:528:DyaK28XhtFSjtb0%3D
• ISSN: 13482246
• ISSN: 09106340
• Web Site: https://link.springer.com/content/pdf/10.2116/analsci.12.31.pdf
• Web Site: https://link.springer.com/article/10.2116/analsci.12.31/fulltext.html
• Web Site: http://www.jstage.jst.go.jp/article/analsci1985/12/1/12_1_31/_pdf
• Text Lang: en
• Data Source:
  • JaLC
  • Crossref
  • CiNii Articles
• Abstract License Flag: Disallowed