Europium acetylacetone

Extraction of the rare earths with acetylacetone has been investigated [418, 419] and is found to be enhanced by the decreasing basicity of the rare earth ions. The gas chromatographic separation of rare earth complexes with 2,2,6,6-tetramethyl-3,5-heptanedione has already been mentioned. The acetylacetonate complexes of the rare earths are reported to exist as either anhydrous [420, 421], mono- [422], di- [422] or trihy-drates [422, 423], Stites et al. [424] have studied the pH of the precipitation of several rare earth acetylacetonates and reported the melting points of the complexes. The europium acetylacetonate precipitated at pH 6.5, and melted at 144—45° C. The existence of monomers and dimers for these complexes in nonaqueous solvents has been proposed [421, 425-427],... 

Ethylene Glycol, Tetradeuterated i 208-0024 Europium Acetylacetonate Complex j 209-0002... 

A broad range of metal centers have been used for the complexation of functional ligands, including beryllium [37], zinc, transition metals such as iridium [38], and the lanthanide metals introduced by Kido [39], especially europium and terbium. Common ligands are phenanthroline (phen), bathophenanthrolin (bath), 2-phenylpyridine (ppy), acetylacetonate (acac), dibenzoylmethanate (dbm), and 11 thenoyltrifluoroacetonate (TTFA). A frequently used complex is the volatile Eu(TTFA)3(phen), 66 [40]. 

SWV was used for the investigation of charge transfer kinetics of dissolved zinc(II) ions [215-218] and uranyl-acetylacetone [219], cadmium(II)-NTA [220] and mthenium(III)-EDTA complexes [221], and the mechanisms of electrode reactions of bismuth(III) [222], europium(III) [223,224] and indium(III) ions [225], 8-oxoguanine [226] and selenium(IV) ions [227,228]. It was also used for the speciation of zinc(II) [229,230], cadmium(II) and lead(II) ions in various matrices [231-235]. 

These considerations are probably also of value in the study of Eu + luminescence in chelates. Napier et al. 80) have recently demonstrated the importance of the Eu3+ c.t. state for the absence of Eu3+ emission in tris (acetylacetonate) europium(III). 

Similar to chemical vapor deposition, reactants or precursors for chemical vapor synthesis are volatile metal-organics, carbonyls, hydrides, chlorides, etc. delivered to the hot-wall reactor as a vapor. A typical laboratory reactor consists of a precursor delivery system, a reaction zone, a particle collector, and a pumping system. Modification of the precursor delivery system and the reaction zone allows synthesis of pure oxide, doped oxide, or multi-component nanoparticles. For example, copper nanoparticles can be prepared from copper acetylacetone complexes [70], while europium doped yttiria can be obtained from their organometallic precursors [71]. 

An important class of chiral, nonfluorinated lanthanide shift reagents contain acetylacetonate ligands in which the pendant methyl groups are replaced by chiral residues, e.g.. europium(III) tris[(7 ,l )-dicampholylmethanate] [Eu(dcm)3, see Table 1 and Figure 9]89. 

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

In the above examples, the nucleophilic role of the metal complex only comes after the formation of a suitable complex as a consequence of the electron-withdrawing effect of the metal. Perhaps the most impressive series of examples of nucleophilic behaviour of complexes is demonstrated by the p-diketone metal complexes. Such complexes undergo many reactions typical of the electrophilic substitution reactions of aromatic compounds. As a result of the lability of these complexes towards acids, care is required when selecting reaction conditions. Despite this restriction, a wide variety of reactions has been shown to occur with numerous p-diketone complexes, especially of chromium(III), cobalt(III) and rhodium(III), but also in certain cases with complexes of beryllium(II), copper(II), iron(III), aluminum(III) and europium(III). Most work has been carried out by Collman and his coworkers and the results have been reviewed.4-29 A brief summary of results is relevant here and the essential reaction is shown in equation (13). It has been clearly demonstrated that reaction does not involve any dissociation, by bromination of the chromium(III) complex in the presence of radioactive acetylacetone. Furthermore, reactions of optically active... 

The solid state fluorescence spectra of some Eu, Sm, and nitrate, chloride, and acetylacetonate (acac) complexes of 1,8-naphthyridine (napy) and 2,7-dimethyl-1,8-naphthyridine (2,7-dmnapy) are recorded. The relative fluorescence intensities of analogous complexes of the same metal are in the order NOs > CT > acac and 2,7-dmnapy > napy. The Stark splittings of the europium emission lines are consistent with site symmetries of Cg for the 10-coordinate Eu(napy)g(NOs)s, of C for the 8-coordinate Eu(acac)s-(2,7-dmnapy), and of Cs for the chloride arrangement in the 11-coordinate EuCU(napy)g(HgO). 

The band intensities of the dysprosium and europium complexes are fairly similar except for the acetylacetonate (acac) adducts. The assignments for the two ion emission bands observed for the dysprosium complexes are F9/2- Hi5/2 at 480 nm and Fq/2- His/2 at 572 nm (21). For many other dysprosium complexes, a band assigned to the F9/2- Hii/2 transition was also reported at approximately 650 nm (5, 16). Second-order scatter radiation from the excitation source which occurs in this region prevented observation of this transition. The europium complexes have only two available resonance levels, Dq and Di (8, 9, 22). For the appropriate assignments for the observed bands, see Table I. The Do- F2... 

Acetylacetone reacts with an ethanol solution containing a salt of europium to give a compound that is 40.1% C and 4.71% H by mass. Combustion of 0.286 g of the compound gives 0.112 g EU2O3. Assuming the compound contains only C, H, O, and Eu, determine the formula of the compound formed from the reaction of acetylacetone and the europium salt. (Assume that the compound contains one europium ion.)... 

Acetylacetone is one of the few j8-diketone that can sensitize terbium because more extended j8-diketones usually have a triplet state lower than the emissive level of Tb +. Dibenzoylmethane (Hdbm) is an example of such an extended y3-diketone. Here, two phenyl moieties are replacing the methyl group of Hacac (Scheme 1). The deprotonation joins the two acetophenone chromophore together. The absorption of dbm then goes up to the visible spectrum. The absorption of some blue light yields a yellow solution under daylight. The triplet state is well suited for europium, which is well sensitized by dbm , provided that an additional neuttal molecule such as phenanthroline is added to complete the coordination sphere. 

As an alternative to doped QDs, ZnSe QDs capped with a europium complex were synthesised by the quick injection of selenium powder dissolved in ODA and TBP into a hot reaction mixture of zinc stearate and the Eu compound (either the acetate or acetylacetonate complex) in octadecene (ODE) at 310 °C. The XRD patterns of the resulting particles matched with the zinc blende phase of ZnSe and the particle size varied from ca. 3-4 nm in diameter according to TEM. X-ray photoelectron spectroscopy (XPS) showed that Eu was bonded to the surface of the Se ions. The as-synthesised hybrid QDs showed emission peaks from ZnSe QDs (455 nm) and the... 

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