Terbium tris

Terbium, tris(2,2,6,6-tetramethyf-3,5-heptanedione)-photosubstitution, 1,408 Terbium complexes f5-diketones, 3, 1081... 

They illustrated the effects of impurities by data taken on europium tris-benzoylacetonate (EuBA), europium tris-dibenzoylmethide (EuD3), and terbium tris-acetylacetonate (TbAA) chelates. 

Chauvin, A.-S., Gumy, F., Imbert, D., and BunzU, J.-C.G (2004) Europium and terbium tris(dipicolinates) as secondary standards for quantum yield determination. Spectroscopy Letters, 37 (5), 517-532. 

Europium and terbium tris(dipicolinates) are known to be highly luminescent, with overall quantum yields of 24% and 22%, respectively, and lifetimes of 1.67 and 1.43 ms, respectively. This property is taken advantage of in simple luminescent methods for the determination of nanomolar concentrations of lanthanides (Barela and Sherry, 1976). In fact, both the quantum yield and lifetime heavily depend on the concentration of the chelates and the pH since the latter governs the speciation in solution (Eigure 38). Three or six water molecules are coordinated onto the metal ion in the lower bis and monospecies, respectively. As a consequence, the corresponding quantum yields and lifetimes are drastically reduced with respect to the tris-species. Eor instance, a quantum yield of only 4.5% has been determined for [Eu(dpa)2] (Aebischer et al., 2009) while t( Do) = 0.35 ms only for this complex (Chauvin et al., 2004). 

Figure 5.14 Linear microscopy imaging (UV irradiation at 365 nm) of a lysosyme-derivative crystal containing terbium tris-dipicolinate (left), nonlinear two-photon microscopy under 532 nm laser irradiation (right). Reproduced from [601. Copyright 2007, John Wiley...

Carl Gustaf Mosander, a Swedish chemist, successfully separated two rare-earths from a sample of lanthanum found in the mineral gadolinite. He then tried the same procedure with the rare-earth yttria. He was successful in separating this rare-earth into three separate rare-earths with similar names yttia, erbia, and terbia. For the next 50 years scientists confused these three elements because of their similar names and very similar chemical and physical properties. Erbia and terbia were switched around, and for some time the two rare-earths were mixed up. The confusion was settled ostensibly in 1877 when the chemistry profession had the final say in the matter. However, they also got it wrong. What we know today as erbium was originally terbium, and terbium was erbium. 

Bkouche-Waksman, I. Guilhem, J. Pascard, C. Alpha, B. Deschenaux, R. Lehn, J.-M. 110. Crystal structures of the lanthanum(III), europium(III), and terbium(III) cryptates of tris(bipyridine) macrobicyclic ligands. Helv. Chim. Acta 1991, 74,1163-1170. 

Huffman (87) studied the transient emissions from terbium in a vinylic resin matrix. His compound was Tb tris-[4,4,4-trifluoro-l-(2-thienyl)-1,3-butaneodione] in polymethylmethacrylate. This may be conveniently abbreviated as TbTTA in PMMA. The compound EuTTA in PMM A had previously been reported by Wolff and Pressley (99) to give laser oscillation. Working with small fibers at 77°K, Huffman found distortions from the normal fluorescent decay curves when the optical pumping was large. He interprets this as evidence for stimulated emission. A comparison of these distorted decays with EuTTA in PMMA indicated a similar behavior, thus tending to substantiate his hypothesis. 

Voloshin AI, Shavaleev NM, Kazakov VP. Water enhances photoluminescence intensity of europium(III), terbium(III) and samarium(III) tris-P-diketonates in toluene solutions and chemiluminescence intensity of europium(III) and samarium(III) tris-P-diketonates in the reaction with dioxetane. J Photochem Photobiol A Chemistry 2000 136 203-8. 

Figure 135 Molecular structures of lanthanide complexes of europium (Eu), tris (thenoyltrifluoroacetonato) Eu3+ (a), tris(thenoyltri-fluoroacetonatoXmonophenanthroline) Eu3+ (b), and terbium (Tb), tris(acetylacetonato) Tb3+ (c) employed as narrow-band emitters in organic EL devices (see Ref. 19, 425, 534-536 and 539).

Pyrazolone and its derivative are the most common ligands used for Tb(III) complexes in electroluminescence. In 1998 the first example of an electroluminescent device using a terbium pyrazolonate complex, tris(l-phenyl-3-methyl-4-isobutyl-5-pyrazolone)-bis-(triphenyl phosphine oxide) terbium [Tb(ip-PMP)3(TPPO)2] (Figure 11.20, compound 36),... 

Photoluminescence of tris-bipyridine europium and terbium(III) clathrochelates in aqueous solutions and in the solid state has been studied in the temperature range from 4.2 to 300 K [212, 374, 390-394]. It has been assumed that luminescence is favoured by (a) the inertness of clathrochelates (b) the complete encapsulation of the rare earth metal ion in macrobicyclic ligand cavities, preventing deactivation of these luminescent ions owing to interaction with the solvent molecules and (c) the possibility of energy transfer from the ligand chromophore to the luminescent ion. 

Low-temperature studies of solid tris-bipyridine europium, terbium, lanthanum(III), and sodium clathrochelates were performed on UV excitation [390]. The lanthanum (III) and sodium clathrochelates were examined to get more information on the luminescent properties of the ligand. These clathrochelates showed luminescence at temperatures below 100 K upon longwave UV excitation corresponding to ligand-centred absorption. The quantum yield of the ligand phosphorescence is co 0.02. An increase of temperature results in a drastic decrease in the luminescence intensity, and at 100 K it becomes equal to zero (Fig. 69). 

Fig. 69. Temperature dependence of luminescence intensities for clathrochelate europium (1) and terbium(tll) (2) tris-bipyridinates and the initial macrobicyclic ligand (3).

Terbium clathrochelate showed green emission of very high intensity. The emission spectrum contains the D4 —> Fj transition bands of the encapsulated terbium ion. The same but less intense emission spectrum was observed at higher temperatures. The luminescence quantum yield is close to 1 at 4.4 K and is approximately 0.05 at room temperature [390]. The decrease in intensity of the terbium(III) ion luminescence starts at 100 K (higher than that of free macrobicyclic tris-bipyridine ligand and lower than that of the corresponding europium(III) compound, Fig. 69). It may be... 

TbCls, Terbium chloride, 22 39 TbF,8N 06Pi2C72H72, Terbium(III), hexakis-(diphenylphosphinic amide)-, tris(hexa-iluorophosphate), 23 188 TbNsOuCjHrt, Terbium(ni), trinitrato-(1,4,7,10-tetraoxacyclododecane)-, 23 151... 

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