Lanthanides spectroscopic studies

Group IVB, actinide, and lanthanide, hydrothermal hydrolysis spectroscopic studies. 58-62... 

With a YbPB catalyst at room temperature, 86% yield and 98% ee were obtained. After extensive optimization of the catalyst, solvent, temperature, pressure, and catalytic loading, 98% yield and 98% ee was achieved using YbPB (5 mol%) at 50°C for 48 h in 1 7 THFitoluene. The active catalyst was isolated its structure is similar to that shown in Scheme 5-46, and a similar mechanism was proposed. Additional spectroscopic studies suggested that complexation of the phosphite to the lanthanide center was a plausible first step, and that the P-C bond is formed by nucleophilic attack of phosphoms on an N-complexed imine [34]. 

It is evident that the approach described so far to derive the electronic structure of lanthanide ions, based on perturbation theory, requires a large number of parameters to be determined. While state-of-the-art ab initio calculation procedures, based on complete active space self consistent field (CASSCF) approach, are reaching an extremely high degree of accuracy [34-37], the CF approach remains widely used, especially in spectroscopic studies. However, for low point symmetry, such as those commonly observed in molecular complexes, the number of CF... 

ILs is in the range of 230-250 nm) which make them suitable to be used as solvents for spectroscopic measurements especially in the visible region. Because of their ionic origin, ILs allow the coordination of a complex compound in a liquid sfafe to be sfudied. An additional advanfage of ILs is that their solvating properties can be designed in such a way that differently coordinating solvents are obtained. A lot of examples can be presented on spectroscopic studies with lanthanides and actinides. 

Costes, J.-P. Dupuis, A. Commenges, C. Lagrave, S Laurent, J.-P. Mononuclear lanthanide complexes of tripodal ligands synthesis and spectroscopic studies. Inorg. Chim. Acta 1999, 285, 49-54. 

Tei, L., Baum, G., Blake, A.J., Fenske, D., and Schrooder, M. Lanthanide complexes of a new nonadentate ligand derived from 1,4,7-triazacyclononane synthesis, structural characterisation and NMR spectroscopic studies,/. Chem. Soc., Dalton Trans. (2000), 2793-2799. 

Spectroscopic studies of polyoxometalates and their complexes with lanthanide (III) ions in solution Lis (1996)... 

The structure of a genuine six-coordinate lanthanide complex namely, Er(NCS)6 in C4H903NEr(NCS)6 was determined by Martin and coworkers [28]. Earlier spectroscopic studies predicted the octahedral disposition of this complex [29]. The geometrical... 

Wang, Z.-M., van de Burgt, L.J., and Choppin, GR. (1999) Spectroscopic study of lanthanide(lll) complexes with carboxylic acids. Inorganica Chimica Acta, 293, 167-177. 

The enhancement of the extraction of Ln(III) ions with ttfaH in cyclohexane or benzene by the addition of Cr(acac)3 was investigated . The equilibrium analysis suggested that the effect of Cr(acac)3 could be ascribed to the formation of a binuclear 1 1 La(ttfa)3-Cr(acac)3 adduct. The formation constants of adducts along the lanthanide series decreased with the decrease of the ionic radii among the light lanthanides and were constant for their heavy counterparts. UVV, IR and H NMR spectroscopic studies were also performed to explain the molecular structural differences between the light and heavy lanthanide complexes. 

For a spectroscopic study of in situ generated lanthanide ketyl species, see Hirota N, Weissman SI (1964) J Am Chem Soc 86 2538... 

A. Electron-Phonon Interaction Parameterization Scheme. In observing the fluorescence decay rate from a given J-manifold, it is generally found that the decay rate is independent of both the crystal-field level used to excite the system and the level used to monitor the fluorescence decay. This observation indicates that the crystal-field levels within a manifold attain thermal equilibrium within a time short compared to the fluorescence decay time. To obtain this equilibrium, the electronic states must interact with the host lattice which induces transitions between the various crystal-field levels. The interaction responsible for such transitions is the electron-phonon interaction. This interaction produces phonon-induced electric-dipole transitions, phonon side-band structure, and temperature-dependent line widths and fluorescence decay rates. It is also responsible for non-resonant, or more specifically, phonon-assisted energy transfer between both similar and different ions. Studies of these and other dynamic processes have been the focus of most of the spectroscopic studies of the transition metal and lanthanide ions over the past decade. An introduction to the lanthanide work is given by Hiifner (39). 

The mechanisms of actinide/lanthanide binding to transferrin may not be the same as that for iron( III). Spectroscopic studies by Duffield and Taylor(1987) have shown the fine details of Pu(IV) and Th(IV) binding to transferrin to be very similar to that of Fe(III). 

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