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Diethylenetriaminepentaacetic acid (DTPA) is a chelating agent whose complex with the Gd3+ ion is used in medical imaging. DTPA is also used in lanthanide‐actinide separation processes. As protonation of the DTPA ligand can facilitate dissociation of the Gd3+ ion from the Gd‐DTPA complex, this work investigates the coordination structures of the aqueous Gd3+ ion and its environment when chelated by DTPA in eight different DTPA protonation states. Both classical and ab initio molecular dynamics (MD) simulations are conducted to model the solvated complexes. Extended X‐ray absorption fine structure (EXAFS) measurements of the Gd3+aqua ion, and the Gd‐DTPA complex at pH 1 and 11, are compared to EXAFS spectra predicted from the MD simulations to verify the accuracy of the MD structures. The findings of this work provide atomic‐level details into the fluctuating Gd‐DTPA complex environment as the DTPA ligand gradually detaches from the Gd3+ ion with increased protonation. [ABSTRACT FROM AUTHOR]

The water soluble [[Tb(dipicCbz).sub.3].sup.3-] (dipicCbz = 4-(9H-carbazol-9-yl-)pyridine-2,6-dicarboxylato) complex was isolated and evaluated as a temperature sensor in water. The 1:3 [(Tb.sup.III]:dipicCb[z.sup.2-]) stoichiometry in solution was confirmed by luminescence titration and high-resolution mass spectrometry. The quantum yield of sensitized emission is 3.8% [+ or -] 0.4% at 25.0 [+ or -] 0.1 [degrees]C, and the emission intensity depends on the temperature in the range of 5-70 [degrees]C with a relative thermal sensitivity of 3.4% [degrees][C.sup.-1] at 35 [degrees]C and temperature resolution < 0.01 [degrees]C in the range of 30-40 [degrees]C. The reversibility of this behavior was demonstrated for three heating--cooling cycles. Calculations of the energy gap between donor and acceptor show that the temperature dependence of the emission intensity is due to back-energy transfer from the Tb [.sup.5][D.sub.4] excited state to the triplet and twisted intramolecular charge transfer (TICT) states of the dipicCbz. The assignment of one of the energy levels as a TICT state was confirmed by the temperature-dependent behavior of the phosphorescence band. Key words: lanthanides, terbium, temperature probe, luminescence. Resume: Nous avons isole le complexe hydrosoluble [[Tb(dipicCbz).sub.3].sup.3-] (dipicCbz = 4-(9H-carbazol-9-yl)pyridine-2,6-dicarboxylato) et nous l'avons evalue en tant que capteur de temperature dans l'eau. La stcechiometrie de 1:3 ([Tb.sup.III]:dipicCb[z.sup.2-]) a ete confirmee en solution par titrage de luminescence et par spectroscopie de masse a haute resolution. Le rendement quantique de l'emission sensibilisee est de 3,8 [+ or -] 0,4 % a 25,0 [+ or -] 0,1 [degrees]C, et l'intensite de l'emission depend de la temperature dans l'intervalle de5a70[degrees]C, avec une sensibilite thermique relative de 3,4 % [degrees][C.sup.-1] a 35 [degrees]C et une resolution de temperature < 0,01 [degrees]C dans l'intervalle de 30 a 40 [degrees]C. Nous avons demontre le caractere reversible de ce comportement sur trois cycles de chauffage-refroidissement. Les calculs de la bande d'energie interdite entre le donneur et l'accepteur montrent que la relation de dependance entre l'intensite de l'emission et la temperature est attribuable au transfert d'energie reversible de l'etat excite [.sup.5][D.sup.4] du Tb a l'etat triplet et a l'etat de transfert de charge intramoleculaire deforme dit << TICT >> (twisted intramolecular charge transfer) du ligand dipicCbz. L'attribution de l'un des niveaux d'energie a un etat TICT a ete confirmee par le fait que la bande de phosphorescence varie en fonction de la temperature. [Traduit par la Redaction] Mots-cles: lanthanides, terbium, sonde de temperature, luminescence., Introduction Temperature is an important thermodynamic and kinetic variable in reactions and biochemical processes. In living systems, abnormalities in the temperature are indicative of diseases. (1) For example, cancer cells [...]

Abstract: We synthesized thiophene-functionalized pyrene, peropyrene, and teropyrene through a two- or four-fold alkyne annulation reaction promoted by triflic acid. All of the target compounds were fully characterized spectroscopically, and [...]

The complete solid-state characterization and solution photophysics of several new complexes of lanthanide ions as possible sensitizers of Eu(III) and Tb(III) with thiophene-derivatized nitrobenzoic acids is reported. The compounds dissolve in water and methanol and methanol solutions were found to be luminescent which have metal ion-to-ligand ratio of 1:1.

The preparation of the Er(sub n)Sc(sub 3-n)N@C(sub 80) (n=0-3) family of endohedrals, the isolation of ErSc(sub 2)N@C(sub 80) and its detailed structural characterization by the single-crystal x-ray diffraction are reported. Even though the C(sub 80) cages are located on a crystallographic mirror plane that plane does not coincide with a mirror plane of the cages themselves and consequently, the cage is disordered over four superimposed sites.