Europium perchlorate

Stewart [505, 585] was the first to investigate systematically the spectra of the rare earth aquo ions, and he reported the following absorption maxima for the Eu3+ ion. It will be seen that the absorption bands in the visible region are of very weak intensity. Later Banes and Kjlengman [586] measured the same spectra using a Cary 14 spectrophotometer and their results for the Eu3+ ion are also reproduced below. A broad band at 1880 A (53190 cm-1) has been observed [587] for 0.03 M europium perchlorate in 0.1 M HGLO4 which may possibly be due to a 4/ - 5d transition of the /8 configuration. 

Fig. 10.24. The methyl multiplet in the NMR spectrum of the cobalt complex. (B) The separation of the methyl signals after addition of excess europium perchlorate.

Question 4.9 Expiain why europium nitrate forms a 1 1 complex [Eu(terpy)(N03)3(H20)] but europium perchlorate forms a 3 1 complex [Eu(terpy)3](C104)3. 

As can be seen from the Table, the oscillator strengths obtained for the glasses are higher than those obtained for aqueous solutions with the exception of the Fo — Le transition. We also note that the oscillator strength for the Fq — Dq transition in the glass is appreciable considering the zero value reported for the europium perchlorate solution. The... 

Absorption and emission spectra of europium perchlorate and nitrate have been measured in protonated and deuterated solvents water, DMSO, methanol and acetonitrile (Haas and Stein 1971a,b). With nitrate as the anion, the complexing ability decreases in the order water > methanol > acetonitrile. 

Lis S, Choppin GR. Luminescence lifetimes of aqueous Europium perchlorate chloride and nitrate solutions. Materials Chemistry and Physics. 1992 31(1/2) 159 161. 

Diorganotin(IV) complexes with 4//-pyrido[l,2-n]pyrimidin-4-ones 109 (96MI4), complexes of 2-methyl- and 2-methyl-8-nitro-9-hydroxy-4//-pyrido[l,2-n]pyrimidin-4-ones with Ag(I), Cu(II), Ni(II), Co(II), and Mn(II) ions (00MI23), 2,4-dimethyl-9-hydroxypyrido[l, 2-n]pyrimidinium perchlorate and its complexes with prasedynium, neodymium, samarium and europium (00MI24) were characterized by UV spectroscopy. 

By means of a stopped-flow technique, Carlyle and Espenson ° ° have subjected the reaction between europium(II) and iron(III) to a detailed examination. In perchloric acid solution two processes are discerned, viz. 

The combination of dicyclopentadienylzirconium dichloride and silver perchlorate activates armed glycosyl sulfoxides in dichloromethane between -20 °C and room temperature, but only very simple acceptors were studied [335]. Other Lewis and Bronsted acids studied include the environmentally benign europium, lanthanum and ytterbium triflates [336], certain polyoxometallates [337], sulfated zirconia [338] and Nafion H [338]. 

In dry aprotic solvents such as acetonitrile [28] with tetraethylammonium bromide as supporting electrolyte or dimethylformamide [29] with sodium perchlorate as supporting electrolyte, the ( ) / rneso ratio for pinacols rises substantially in favour of the ( )-form. Reduction of acetophenone in dimethylformamide in the presence of europium(ni) chloride leads to the ( )-pinacol only. Under these reaction conditions, europium(ii) is formed and dimerization occurs with the involvement of this ion and the ketone in a complex [30]... 

For expanding NMR spectra of aqueous sample solutions, lanthanide salts such as the chlorides, nitrates, or perchlorates of europium and praseodymium are used [103]. In organic solvents, tris-(/ -diketonato)-europium(III) chelates (1) are usually applied [103]. Chiral europium(III) chelates such as tris-(3-tm-butylhydroxymethylene)-D-camphora-to-europium(III) (2) separate the signals of enantiomers in the NMR spectra of racemic solutions [103],... 

Alyapyshev, M.Yu., Babain, V.A., Smirnov, I.V., Shadrin, A.Yu. 2006. Separation of americium and europium from solutions of nitric and perchloric acid using dipicolinic acid diamides. Czech. J. Phys. 56, Suppl. D D469-D475. 

The situation with different metals is almost opposite. It was shown that the influence of dibenzo-24-crown-8, dicyclohexyl-18-crown-6 (DCH18C6), or trioctylphos-phine oxide on the extraction of europium by dinonylnaphthalenesulfonic acid (HDNNS) in benzene from nitrate and perchlorate solutions is negative. That is, an antisynergistic or antagonistic effect is observed.53... 

The complexes formed with cyclopropylene urea (CPU) have the formula [193] Ln(CPU)8X3, where X = CIOJ, NO. Complexes of this composition have been synthesized with all the lanthanides when the anion is perchlorate. When X = nitrate it was possible to synthesize complexes for the early lanthanides (i.e.) La to Gd. In both cases the anions are not coordinated as evidenced by IR spectra. Europium complexes, with X = CIO, NOJ, I-, PFg have been found to be of the same symmetry around Eu(III) as evidenced by their emission spectra [178]. 

A derivative of the (bpy.bpy.bpy) cryptand, obtained by modifying one of the chains, Lbpy, forms a di-protonated cryptate with EuCb in water at acidic pH, [EuCl3(H2Lbpy)]2+ in which the metal ion is coordinated to the four bipyridyl and two bridgehead nitrogen atoms, and to the three chlorine ions (Fig. 4.25). The polyamine chain is not involved in the metal ion coordination, due to the binding of the two acidic protons within this triamine subunit. In solution, when chlorides are replaced by perchlorate ions, two water molecules coordinate onto the Eu(III) ion at low pH and one at neutral pH, a pH at which de-protonation of the amine chain occurs, allowing it to coordinate to the metal ion. As a result, the intensity of the luminescence emitted by Eu(III) is pH dependent since water molecules deactivate the metal ion in a non-radiative way. Henceforth, this system can be used as a pH sensor. Several other europium cryptates have been developed as luminescent labels for microscopy. 

Tridentate N-donor ligands are efficient in separating actinides from lanthanides selectively by solvent extraction, an area of potential great importance in treatment of used nuclear fuel rods. The tridentate ligand 2,2 6 ,2 -terpyridyl (terpy) forms a range of complexes. The perchlorate complexes [Ln(terpy)3] ( 104)3 contain nine-coordinate cations with near- )3 symmetry, a structure initially deduced from the fluorescence spectrum of the europium compound (Section 5.4) and subsequently confirmed by X-ray diffraction smdies (Figure 4.7)... 

Reaction of terpy with lanthanide perchlorates in MeCN affords [La(terpy)3](C104)3-2MeCN0.67H20, [Ln(terpy)3] (C104)3-MeCN.H20 (Ln = Ce, Pr, Sm, Eu), [Lu(terpy)3] (C104)3 (Eu, Lu, Y) all of these have uiue-coordinate [Lu(terpy)3] + cations with near-Ds synunetry, a structure origiuaUy deduced from the fluoresceuce spectrum of the europium complex and subsequently confirmed by X-ray diffraction (Figure 19). 

Finally we note that recently beautiful extended vibronic spectra have been reported by Berry et al. (154) for hexakis (antipyrine) europium (III) tri-iodide and tri-perchlorate. More than 50 lines belonging to the Fo - D2 transition were reported. 

Reduction in dry aprotic solvents allows the formation of ion pairs between the radical anion and a countercation. Where the cation can interact simultaneously with two radical species, dimerization favors the ( )-product because there are fewer steric interactions, in the corresponding transition state, between groups attached to the reacting radicals. Solvent and supporting electrolyte combinations that give a high yield of ( )-pinacol are acetonitrile with tetraethylammonium bromide [82], dimethylformamide with sodium perchlorate [83], and dimethylformamide with europium(III) chloride. Europium(II) is formed in the last... 

Materials. Solutions of Eu, Th, and U were made by dissolving known amounts of the metal oxides in nitric or perchloric acid. The europium solution was standardized by titration with EDTA using xylenol orange indicator at pH 5.2. 

Lochhead MJ, Wamsley PR, Bray KL. Luminescence spectroscopy of europium(III) nitrate, chloride, and perchlorate in mixed ethanol- water solutions. Inorg Chem 1994 33 2000-3. 

The lutetium hahdes (except the fluoride), together with the nitrates, perchlorates, and acetates, are soluble in water. The hydroxide oxide, carbonate, oxalate, and phosphate compotmds are insoluble. Lutetium compounds are all colorless in the solid state and in solution. Due to its closed electronic configuration (4f " ), lutetium has no absorption bands and does not emit radiation. For these reasons it does not have any magnetic or optical importance, see also Cerium Dysprosium Erbium Europium Gadolinium Holmium Lanthanum Neodymium Praseodymium Promethium Samarium Terbium Ytterbium. 

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