Comparative Study of the Luminescence Properties and Relative Stability of a Series of Europium(III) Complexes Bearing One to Four Coordinated Azaxanthone Groups

Parker, David; Walton, James W.; Lamarque, Laurent; Zwier, Jurriaan M.

doi:10.1002/ejic.201000501

Cited by 23 publications

(14 citation statements)

References 30 publications

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“…[32] This points to single species in solutions or mixtures of species in rapid equilibrium. The emission lifetimes recorded in H 2 O solution (0.75 and 0.80 ms for EuL1 and EuL2, respectively), are longer than those generally observed for mono-and bis-hydrated Eu 3+ complexes, [33] but shorter than those observed for q = 0 complexes with ligands based on DO3A derivatives. [34] The number of inner-sphere water molecules (q) was calculated using Equation (3).…”

Section: Absorption and Emission Electronic Spectroscopymentioning

confidence: 90%

Lanthanide Complexes with Heteroditopic Ligands as Fluorescent Zinc Sensors

et al. 2014

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International audienceWe report the synthesis of two ligands containing a DO3A unit (H3DO3A = 1,4,7,10-tetraazacyclododecane-1,4,7-triacetic acid) linked to a triazacyclononane (TACN) moiety by a 2,6-dimethylpyridine spacer designed to form stable Ln3+ complexes in solution that respond to the presence of Zn2+ ions. The Eu3+ and Gd3+ complexes have been characterized by using a combination of experimental and theoretical techniques that include absorption and emission electronic spectroscopy, NMR spectroscopy, 1H relaxometry, and DFT calculations. The Ln3+ ions are eight-coordinated by the ligand, which binds to the metal ion through the seven donor atoms of the DO3A unit and the nitrogen atom of the pyridyl linker. Luminescence lifetime measurements recorded from solutions of the Eu3+ complexes in H2O and D2O and relaxometric measurements point to the absence of inner-sphere water molecules. The addition of Zn2+ causes important changes in the absorption spectra of the complexes that evidence the formation of both 1:1 and 2:1 (Ln3+/Zn2+) complex species. However, the emission lifetimes of the Eu3+ complexes and relaxivity experience weak changes, thus indicating that Zn2+ addition does not significantly affect the number of coordinated water molecules. The Gd3+ complexes show a weak emission band at 325 nm, the intensity of which dramatically increases in the presence of Zn2+. However, the “turn-on” behaviour induced by Zn2+ is not observed for other metal cations such as Ca2+, Mg2+ or Cu2+. DFT calculations indicate that a photoinduced electron-transfer (PET) process is responsible for the quenching of the luminescence in the absence of Zn2+

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Section: Absorption and Emission Electronic Spectroscopymentioning

confidence: 90%

Lanthanide Complexes with Heteroditopic Ligands as Fluorescent Zinc Sensors

et al. 2014

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“…In a study comparing the properties of a series of europium(III) complexes with cyclen azaxanthone macrocycles, that have from one to four azaxanthone pendant arms, L 45 was found to have the best overall behaviour with a 10% emission quantum yield and the highest stability. 76 The europium(III) trisamide cyclen complex with L 46 was used as part of a photactivated luminescent system where a coordinating antenna for sensitisation of the metal centre was released on irradiation. 77 The luminescent process is optimal in the presence of a surfactant when a micellar domain is formed bringing the two components together in higher effective concentrations.…”

Section: Luminescent Lanthanide Complexesmentioning

confidence: 99%

“…The NS 2 macrocycle L 75 was used to form coordination polymers on complexation with mercury(II) and silver(I) ions, and the X-ray structures showed anion dependent forms for mercury(II). 122 Macrocycle, L 76 , was used to form a discrete mixed valence bimetallic complex with cobalt and iron. 123 The cobalt(III) ion is encapsulated within the macrocycle and linked via a bridging pyrazine unit to an [Fe(CN) 5 ] 3À moiety.…”

Section: N/s O/s and N/s/o Mixed Donor Macrocyclesmentioning

confidence: 99%

Macrocyclic coordination chemistry

Archibald

2011

Annu. Rep. Prog. Chem., Sect. A: Inorg. Chem.

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This chapter reviews the literature published on macrocyclic coordination chemistry during 2010. The aim is to describe the key advances, focusing predominantly on complexes formed with transition metal and lanthanide ions. Porphyrin ligands and supramolecular chemistry are not covered. Trends in the development of macrocyclic chelator design and the impact of the coordination chemistry on both existing and emerging applications are discussed. HighlightsKey advances in 2010 include: The further development of macrocyclic oxo, superoxo and peroxo metal complexes was achieved with the isolation of an iron(IV) oxo compound formed stoichiometrically from the reaction of an iron(II) compound with hydrogen peroxide, and the formation of a chromium(III) superoxo compound that reacts with activated C-H bonds via H abstraction. 1,2 Efficient catalysis was observed by the immobilisation of hydroxy bridged manganese tacn dimers on a silica surface. 3 Hyperpolarised 89 Y was used as a model to study the kinetics of chelation of a DOTA-amide chelator with lanthanides giving a similar result to measurements made on gadolinium(III) complexes and indicating that this method may be of more widespread use in the analysis of lanthanide complex formation. 4 The stabilisation of the europium(II) oxidation state was achieved using a cryptand complex by the replacement of O-donors with S-donors suggesting the potential for development of redox-based in vivo sensing using MRI.

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“…114 Europium(III) complexes have been synthesised using cyclen ligands substituted with between one and four 3-azaxanthone sensitising chromophores, the best stability profile being shown by one with two azaxanthone groups. 115 A Tb(III) complex with a cyclen ligand substituted with two 3-azaxanthone groups has been used to selectively stain the chromosomal DNA in dividing cells. 116 Two chiral cyclen-type ligands have been linked with a chiral 1,2-diphenyl-1,2-diaminoethanederived bridge and its Eu 3+ , Tb 3+ and Yb 3+ complexes synthesised; they exhibit differing anion binding profiles.…”

Section: Spectroscopymentioning

confidence: 99%