Water-soluble Lanthanide Complexes Research Articles

Water-soluble lanthanide complexes with bispidine-substituted benzoic acid for luminescent thermometry in a physiological range

A novel material based on europium and terbium complexes with a bispidine-substituted benzoate anion for luminescent thermometry in the physiological temperature range was obtained. The obtained complexes demonstrated intense visible luminescence with quantum yields up to 75%, high water solubility, and high luminescence sensitivity toward temperature (Sr = 2.1% K–1).

Cationic Biphotonic Lanthanide Luminescent Bioprobes Based on Functionalized Cross-Bridged Cyclam Macrocycles.

Cationic lanthanide complexes are generally able to spontaneously internalize into living cells. Following our previous works based on a diMe-cyclen framework, a second generation of cationic water-soluble lanthanide complexes based on a constrained cross-bridged cyclam macrocycle functionalized with donor-π-conjugated picolinate antennas was prepared with europium(III) and ytterbium(III). Their spectroscopic properties were thoroughly investigated in various solvents and rationalized with the help of DFT calculations. A significant improvement was observed in the case of the Eu3+ complex, while the Yb3+ analogue conserved photophysical properties in aqueous solvent. Two-photon (2P) microscopy imaging experiments on living T24 human cancer cells confirmed the spontaneous internalization of the probes and images with good signal-to-noise ratio were obtained in the classic NIR-to-visible configuration with the Eu3+ luminescent bioprobe and in the NIR-to-NIR with the Yb3+ one.

Water-soluble luminescent lanthanide complexes based on C6-DTTA-appended 5-aryl-2,2′-bipyridines

By using a number of synthetic approaches new lanthanide cations ligands based on 5-aryl-2,2′-bipyridines bearing diethylenetriamine tetracarboxylic acid (DTTA) residue at the C6-position of the pyridine moiety were synthesized. By using these ligands the water soluble lanthanide complexes (Ln = Eu, Tb, Sm, Dy) were prepared, and their photophysical properties were studied. For the europium complexes the luminescence quantum yields up to 12.8% and luminescence lifetime up to 1.09 ms were observed. For the terbium complexes of all the ligands a very weak luminescence with quantum yields not higher than 0.43% were observed. The influence of the nature of the bipyridine ligands on the photophysical properties of the lanthanide complexes was also discussed.

Synthesis and luminescence of new water-soluble lanthanide complexes of DTTA-containing 4-(4-methoxyphenyl)-2,2′-bipyridine

Abstract A new DTTA-appended 4-(4-methoxyphenyl)-2,2′-bipyridine ligand has been synthesized for lanthanide cations by Krohnke method. Its luminescent lanthanide (Eu3+ and Tb3+) water-soluble complexes have been synthesized. The photophysical properties of new chelates were studied. Comparison of the new complexes with the known ones has been done; in some cases a red-shift in absorption spectra and higher lanthanide emission quantum yields were observed.

Synthesis and strong luminescence of water soluble lanthanide complexes sensitized by a new tridentate organic ligand

Sensitive biological analysis requires optical labels have good water solubility and relative longer excitation wavelength. Herein, two water-soluble lanthanide (Ln) organic complexes, Na3Ln(DIEDPA)3 (Ln=Eu, Tb) have been synthesized with a new tridentate ligand, 4-[2-(1,3-Dioxo-1,3-dihydro-isoindol-2-yl)-ethoxy]-pyridine-2,6-dicarboxylic acid (H2DIEDPA). The two lanthanide complexes showed characteristic emissions of Eu3+ and Tb3+ ions with high quantum yields of 11±1.1% and 13±1.5% respectively. Moreover, compared with those for the europium and terbium complexes with pyridine-2,6-dicarboxy acid as a ligand, the effective excitation wavelengths for the two complexes shifted more than 60nm to longer wavelengths by decoration of the molecular structure of the organic ligand. The results might provide reference for design and synthesis of organic luminescent lanthanide bioprobes with longer excitation wavelengths.

Water-soluble lanthanide complexes with a helical ligand modified for strong luminescence in a wide pH region

Luminescent helical lanthanide complexes with hydrophilicity were examined for stability and reversibility in a pH region between 1.9 and 11.9.

Photophysical properties of asymmetric and water-soluble dinuclear lanthanide complexes of poly glycol chain functionalized-benzoic acid derivative: experimental and theoretical approaches

New water-soluble lanthanide complexes with a poly glycol chain (–OEtOEtOEtOMe) functionalized benzoic acid derivative ligand were synthesized and photophysically characterized.

Water-soluble Tb(3+) and Eu(3+) complexes based on task-specific ionic liquid ligands and their application in luminescent poly(vinyl alcohol) films.

Novel water-soluble lanthanide complexes (Ln(IMI-DPA)3) have been synthesized using the task-specific ionic liquid consisting of a dipicolinic acid motif as the sensitizer of lanthanide luminescence. In Ln(IMI-DPA)3, Ln(3+) ions are in 9-fold coordination through six carboxylate oxygen atoms and three nitrogen atoms in pyridine units, and the water molecule is excluded from the coordination sphere of the lanthanides. It is found that Ln(IMI-DPA)3 possess bright luminescence, long luminescence lifetime in aqueous solution, high thermal stability and good water solubility. Furthermore, these complexes can be incorporated into water-soluble poly(vinyl alcohol) (PVA) matrixes to obtain highly luminescent, transparent and flexible PVA composite films. The emission colors of the films can be tuned from red, orange, yellow, light green, green to white light by regulating the concentration of the various luminescent components.

Strong luminescence of novel water-soluble lanthanide complexes sensitized by pyridine-2,4,6-tricarboxylic acid

Sensitive biological analysis requires optical labels have good water solubility and excellent luminescent properties. Herein, two water-soluble lanthanide (Ln) complexes, Na 6[Ln(PTA) 3] (Ln = Eu and Tb), have been synthesized with a new tridentate ligand, pyridine-2,4,6-tricarboxylic acid (H 3PTA). The two-lanthanide complexes showed great characteristic emissions of Eu 3+ and Tb 3+ ions with high quantum yields of 54.3 ± 0.5% and 20.2 ± 0.2%, respectively. Moreover, they have good water solubility and can be labelled on biological molecules by dehydration reactions between the non-coordinated –COOH groups from the luminescent complexes and the –NH 2 groups from the biological molecules.

Recognition of metal complex guests: supramolecular extraction of water-soluble lanthanide complexes by biological lasalocid ionophore

Naturally occurring lasalocid ionophore was first demonstrated to extract water-soluble lanthanide tris(acetylacetonates) via inner-sphere complexation into CCl 4. This offered higher extraction abilities for small Er 3+ and Dy 3+ complexes than for large Pr 3+ and La 3+ complexes. Since the lasalocid extracted lanthanide cations themselves non-selectively, this ‘metal complex recognition’ has new and interesting possibilities in separation and sensing of valuable lanthanides.