Sensitization terbium complex

Hildebrandt N, Charbonniere LJ, Lohmannsroben HG (2007) Time-resolved analysis of a highly sensitive forster resonance energy transfer immunoassay using terbium complexes as donors and quantum dots as acceptors. J Biomed Biotechnol 2007 79169... 

Ligands L33 and L34 are both good sensitizers of europium, whilst the former also efficiently sensitizes terbium emission (29). The quantum yield of [EuL34]3+ in aqueous solution, 0.247, is among the highest reported for any europium complex. The lower triplet energy of L34 results in back transfer of energy from the terbium excited state to... 

M. A. Fotopoulou and P. C. Ioannou, Post-Column Terbium Complexation and Sensitized Fluorescence for the Determination of Norepinephrine, Epinephrine and Dopamine Using High-Performance Liquid Chromatography, Anal. Chim. Acta 2002,462, 179. 

Parker and Williams recently reported NAND logic action in the terbium complex 16.[S8] The delayed emission of the lanthanide ion is switched off when H+ and 02 are present simultaneously. Protonation of the phenanthridine side chain causes its triplet excited state to approach theTb(m) 5D4 excited state energetically. This leads to equilibration of these two excited states and sharing of their properties. Thus, the metal-centered state displays the 02 sensitivity usually only found in organic triplets. 

The terbium complex, in contrast, exhibits greatest sensitivity for chloride. Using the achiral ligand (R = H) exhibits similar selectivity for these anions, but with rather less sensitivity. 

In addition, pyrazoyl-azaxanthone can also be used as a sensitizer of lanthanide complexes. An emissive terbium complex Tb-58 incorporating a pyrazoyl-l-aza-xanthonechromophore (Figure 13.25) exhibits cellular uptake and possesses a much lower sensitivity to excited state quenching. For example, Tb-58 was incubated for varying periods of time (from 1 to 12 h 50 or 100 xM complex) with CHO or NIH/3T3 cells. Examination of the loaded cells by luminescence microscopy revealed complex uptake, and localization within endosomes in the cytoplasm, presumably following receptor mediated endocytosis, but no tendency to nuclear localization [75]. 

When Nd or Yb complexes of a similar macrocycle are covalently linked to a palladium porphyrin complex, this sensitizes near-IR emission from the lanthanide, enhanced in the absence of oxygen and in the presence of a nucleic acid7 Another application of luminescence accompanies the terbium complex shown in (39) whose luminescence is enhanced by binding to zinc, and can therefore signal for that metal. " ... 

Fotopoulou, M. A. Ioannou, P. C., Post-column terbium complexation and sensitized fluorescence detection for the determination of norepinephrine, epinephrine and dopamine using high-performance liquid chromatography, Anal. Chim. Acta 2002, 462, 179-185... 

Hayashi has investigated in some detail the ionic photopolymerization of styrene monomers. Free ion lifetimes measured by pulse electrical conductivity measurements were found to agree with those calculated from steady-state conductance measurements. Other studies of interest on radical addition polymerization include the photodimerization of polymers containing thymine bases, diene polymerization by terbium complexes, polymerization of vinyl acetate, and preparation of light-sensitive polyacrylates. 

The donor contribution in the acceptor channel (crosstalk) should be as low as possible the impact of this contribution on a bioassay is not obvious to anticipate starting from a lanthanide complex emission spectrum, since many instmmental factors, such as the filter settings (bandpass width), have to be considered. The intensity distribution between the emission lines is critical, particularly for europium complexes, with a strong impact of the ligand structure and symmetry (for terbium complexes, this impact is reduced). Care must be exercised in comparing published emission spectra, since many of the published spectra are not corrected for the photomultiplicator sensitivity (which falls off rapidly between 650 and 800 nm even using a red PMT ). The consequence is that the 690-nm ( Dq p4) band seems much smaller than its true value. Some articles do indeed show spectra corrected for the sensitivity of the detection system (which contains contributions from the PMT, but also from the monochromators and optics). Whenever such corrections have been applied, this is usually indicated in the experimental section of the article. 

THE DETERMINATION OF COPPER MICROAMOUNTS ON THE TERBIUM LUMINESCENCE SENSITIZED BY IT IN HETEROBINUCLEAR COMPLEX... 

Lanthanides also have potential as DEFRET energy donors. Selvin et al. have reported the use of carbostyril-124 complexes (53) with europium and terbium as sensitizers for cyanine dyes (e.g., (54)) in a variety of immunoassays and DNA hybridization assays.138-140 The advantage of this is that the long lifetime of the lanthanide excited state means than it can transfer its excitation energy to the acceptor over a long distance (up to 100 A) sensitized emission from the acceptor, which occurs at a wavelength where there is minimal interference from residual lanthanide emission, is then measured. 

Different lanthanide metals also produce different emission spectrums and different intensities of luminescence at their emission maximums. Therefore, the relative sensitivity of time-resolved fluorescence also is dependent on the particular lanthanide element complexed in the chelate. The most popular metals along with the order of brightness for lanthanide chelate fluorescence are europium(III) > terbium(III) > samarium(III) > dysprosium(III). For instance, Huhtinen et al. (2005) found that lanthanide chelate nanoparticles used in the detection of human prostate antigen produced relative signals for detection using europium, terbium, samarium, and dysprosium of approximately 1.0 0.67 0.16 0.01, respectively. The emission... 

Ioannou et al. [41] reported the use of terbium sensitized fluorescence to develop a sensitive and simple fluorimetric method for the determination of the anthranilic acid derivative, mefenamic acid. The method makes use of radiative energy transfer from anthranilate to Tb(III) in alkaline methanolic solutions. Optimum conditions for the formation of the anthranilate-Tb(III) complex were investigated. Under optimized conditions, the detection limit was 1.4 x 10-8 mol/L, and the range of application was 2.5 x 10 8 to 5.0 x 10 5 mol/L. The method was successfully applied to the determination of mefenamic acid in serum after extraction of the sample with ethyl acetate, evaporation of the organic layer under a stream of nitrogen at 40°C, and reconstitution of the residue with alkaline methanolic terbium solution prior to instrumental measurement. The mean recovery from serum samples spiked with mefenamic acid (3.0 x 10-6, 9.0 x 10-6, 3.0 x 10-5 mol/L) was 101 5%. The within-run precision (RSD) for the method for the two serum samples varied from 2 to 8%, and the day-to-day precision for two concentration levels varied from 2 to 13%. 

Faulkner, S. and Pope, S.J.A. (2003) Lanthanide-sensitized lanthanide luminescence terbium-sensitized ytterbium luminescence in a trinuclear complex. Journal of the American Chemical Society, 125, 10526. 

The complex of A-(2-pyridinyl)-3-ketobutyramide with Tb + in methanol solution can emit the intrinsic fluorescence of Tb +. When EtsN and Zn + are added to the solution, the fluorescence (kex = 329 nm, ka = 546 nm) is significantly enhanced. This sensitive fluorescence enhancement system can be used for the determination of terbium ion ". ... 

Some lanthanide /3-diketonate complexes (11, M = Pr, Eu, Dy, R = n-Pr, R = f-Bu) have selectivity for further coordination with Cl ions, over F , Br , I , C104, SCN , OH, AcO , HCOs, N03 and SOa ", and are the active component of ion-selective electrodes (ISE) for CG. It was proposed to take advantage of the luminescence in the visible range associated with CH complexation, for the development of specific naked eye optodes (M = Eu) for this ion . A sensitive fiuorescence enhancement system for the determination of terbium was developed and studied. This method was applied to... 

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