Terbium complexes, luminescence

N.B. Terbium complex (luminescent properties) [6230], l-(4-Hydroxy-3-methoxyphenyl)-2-phenylethanone... 

L. Huang, H. Tian, F. Li, D. Gao, Y. Huang, and C. Huang, Blue organic electroluminescent devices based on a distyrylarylene derivatives as emitting layer and a terbium complex as electrontransporting layer, J. Luminescence, 97 55-59 (2002). 

The related bis(pyrazolyl)borate ligand [L5]- forms 10-coordinate complexes of the type [Ln(L5)2(N03)]. The terbium complex in particular has promising luminescence characteristics, with a lifetime of 2.6 ms and quantum yield of 0.36 in methanol (49). However, the complexes are not stable in water. 

Parker, D., Senanayake, P. K., Williams, J. A. G., Luminescent sensors for pH, p0(2), halide and hydroxide ions using phenanthridine as a photosensitiser in macrocyclic europium and terbium complexes. J. Chem. Soc., Perkin Trans. 21998, 2129-2139. 

Luminescence Lifetime Measurements on Various Terbium Complexes (100). 

Zhang, D.Q., Shi, M., Liu, Z.Q., etal. (2006) Luminescence modulation of a terbium complex with anions and its application as a reagent. European Journal of Inorganic Chemistry., (11), 2277-2284. 

Terbium complexes reported for electroluminescence can be separated mainly into two classes terbium carboxylates and P-diketone complexes. Terbium carboxylates have good luminescence but they are difficult to use as efficient emission materials in OLEDs due to their multi-coordination mode and consequent formation of inorganic polymers with poor solubility or volatility. For these reasons, in this section we will focus on use of the newly developed f)-diketonate terbium complexes in OLEDs. 

Figure 11.23 Photo luminescence spectra (Xex = 285nm Xem=545nm) of Tb(tba-PMP)3(TPPO), Tb(tba-PMP)3(H20), and Tb(tba-PMP)3(phen) measured from their 80 nm vacuum evaporated films on quartz substrates [62]. (Reprinted with permission from H. Xin et al., The effect of different neutral ligands on photo luminescence and electroluminescence properties of ternary terbium complexes, The Journal of Physical Chemistry B, 108, 10796-10800, 2004. 2004 American Chemical Society.)...

Li and Wong reported a Tb + complex Tb-26 with pendant aza-15-crown-5 (Figure 13.12) that showed recognition of two important bio-active anions, lactate and salicylate, in aqueous solution [48]. The luminescence lifetime of Tb-26 in H2O was dependent on the nature of the ratio in solution. Upon addition of S.Oequiv of lactate, the luminescence lifetime of Tb-26 increased from 1.45 ms to its maximum of 2.15 ms. Moreover, Tb-26 shows a high selectivity of lactate over other anions such as HCOJ, H2PO4, AcO , and Cl . In addition, two coordi-natively unsaturated terbium complexes Tb-27 and Tb-28 (Figure 13.12) could be displaced upon metal chelation to aromatic carboxylic anions, such as salicylate, in water [49]. 

Recently, we reported a terbium complex Tb(PMIP)3(PhCN) (Tb-29, PMIP= 1-phenyl-3-methyl-4-isobutyl-5-pyrazolone PhCN = pyrazino[2,3-/][l,10] phenanthroline-2,3-dicarbonitrile, Figure 13.13) as a reagent for anions [50]. Interestingly, the luminescent... 

Figure 13.13 Chemical structure of Tb-29 and luminescent titrations of Tb-29 (10 jlM) in CH3CN upon addition of F , CC, Br, I, CIO, NOj, NO2, and AcO [50]. (Reproduced with permission from D.Q. Zhang et al., The luminescence modulation of a terbium complex with fluoride anion and its application for chemodosimeter , European Journal of Inorganic Chemistry, 2006, no. 11, 2277-2284. Wiley-VCH Verlag Gmbh Co. KGaA.)...

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. " ... 

Europium, and to a lesser extent terbium, complexes of /3-diketones have been studied in solution and in the solid state by means of their fluorescence (luminescence) spectra. As explained further in Section 39.2.10, it is possible to relate the splitting of the Do—> F transitions of Eu " to the symmetry of the emitting complex, and studies of circularly polarized luminescence (CPL) spectra can give related information. Thus a study of EuCls and complexes of Eu with hexafluoroacetylacetone and four other /8-diketones in methanol or DMF showed that while EUCI3 itself had axial symmetry in solution, the complexes had orthorhombic symmetry. The emission spectra of solutions of adducts of Eu(dpm)3 with PhsPO or borneol have been studied at low temperatures where conformal lability is reduced the Ph3PO adduct has uniaxial symmetry but the bulky, less symmetrical bomeol molecule confers lower symmetry on its adducts. ... 

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