The structure and stoichiometry of the lanthanide(III) (Ln) complexes with the ligand 2-thenoyltrifluoroacetone (Htta) formed in a biphasic aqueous room-temperature ionic liquid system have been studied by complementary physicochemical methods. Equilibrium thermodynamics, optical absorption and luminescence spectroscopies, high-energy X-ray scattering, EXAFS, and molecular dynamics simulations all support the formation of anionic Nd(tta)4- or Eu(tta)4- complexes with no water coordinated to the metal center in 1-butyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide (C4mim+Tf2N-), rather than the hydrated, neutral complexes, M(tta)3(H2O)n (n = 2 or 3), that form in nonpolar molecular solvents, such as xylene or chloroform. The presence of anionic lanthanide complexes in C4mim+Tf2N- is made possible by the exchange of the ionic liquid anions into the aqueous phase for the lanthanide complex. The resulting complexes in the ionic liquid phase should be thought of as weak C4mim+Ln(tta)4- ion pairs whic...

Mechanisms of Metal Ion Transfer into Room-Temperature Ionic Liquids: The Role of Anion Exchange

Chapter 225 – Rare-earth beta-diketonates

Triboluminescence: Recalling Interest and New Aspects

Luminescent lanthanide coordination polymers composed of lanthanide ions and organic joint ligands exhibit characteristic photophysical and thermostable properties that are different from typical organic dyes, luminescent metal complexes, and semiconductor nanoparticles. Various types of luminescent Eu(III) and Tb(III) coordination polymers have been reported to date. One-, two-, and three-dimensional alternating sequences of lanthanide ions and organic ligands exhibit remarkable characteristics as novel organic materials with various structures, and unique physical properties. In this review, the characteristic structures, photophysical properties, and photonic applications for organic display devices, triboluminescent materials, thermosensors, color and brightness tuning, new type organogels, future magneto-optical materials, luminescent organo-nanoparticles, and energy transfer process of lanthanide coordination polymers are introduced.

Luminescent lanthanide coordination polymers for photonic applications

The 4f–4f emission of Tb(III), Eu(III), and Sm(III) complexes plays an important role in the design of monochromatic green, red, and deep-red luminescent materials for displays, lighting, and sensing devices. The 4f–4f emission of Yb(III), Nd(III), and Er(III) complexes is observed in the near-infrared (IR) region for bioimaging and security applications. However, their absorption coefficients are extremely small (e   10,000 L mol−1 cm−1) are introduced. Organic molecular design elements, including (1) the control of the excited triplet (T1) state, (2) the effects on the charge-transfer (CT) band, and (3) the energy transfer from metal ions for effective photosensitized luminescence, are explained. The characteristic electrosensitized luminescence (electroluminescence) and mechanoluminescence (triboluminescence) of lanthanide(III) complexes are also explained. Lanthanide(III) complexes with well-designed organic molecules are expected to open avenues of research among the fields of chemistry, physics, electronics, and material science. Lanthanide complexes can be made strongly luminescent by designing their ligands so that they act as antenna, find researchers in Japan. With their long luminescence lifetimes and narrow emission bands, lanthanide ions are attractive components for monochromatic luminescent materials. But their low light absorption hinders their widespread use. Yasuchika Hasegawa and co-workers from Hokkaido University, review how this problem can be overcome through using coordinating ligands as antennas. Such ligands absorb incident light and transfer its energy to the lanthanide ion. The researchers emphasize the importance of organic ligands’ excited triplet states and charge-transfer processes. They also discuss cases where luminescence is induced electrically or mechanically (for example, by grinding). The improved luminescence efficiency of such coordination complexes show promise for applications such as displays, solar cells and biomedical sensors. In this paper, the design strategy of trivalent lanthanide (Ln(III)) complexes for effective photo-, electric-, and tribo-sensitized luminescence are reviewed. Ln(III) complexes with well-designed organic molecules are expected to open up a frontier field of chemistry, physics, electronics and material science.

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Effective photosensitized, electrosensitized, and mechanosensitized luminescence of lanthanide complexes

The triboluminescence of three non-ionic europium complexes, Eu(TTA)3·bipy (1), Eu(TTA)3·dia (2) and Eu(DBM)3·dmbp·H2O (3) (TTA = 2-thenoyltrifluoroacetonate, DBM = dibenzoylmethanate, bipy = 2,2′-bipyridine, dia = 4,5-diazafluoren-9-one, dmbp = 4,4′-dimethyl-2,2′-bipyridinate), was observed. Structure determinations of 1 and 3 were carried out. The triboluminescence maxima of 1 and 2 are similar to those of their photoluminescence. The disorder of the thienyl ring and CF3 groups in 1 and the disorder of water in the packing of 3 may be responsible for their triboluminescent activity.

XuHui Zhu

Papers

Triboluminescence and crystal structures of non-ionic europium complexes

Knockdown of the chromatin remodeling ATPase gene Brahma impairs the reproductive potential of the brown planthopper, Nilaparvata lugens.

Xu­Hui Zhu

Papers

Triboluminescence and crystal structures of non-ionic europium complexes

Knockdown of the chromatin remodeling ATPase gene Brahma impairs the reproductive potential of the brown planthopper, Nilaparvata lugens.

XuHui Zhu