A molecular precursor approach to monodisperse scintillating CeF3 nanocrystals

Abstract

A series of anhydrous cerium(III) trifluoroacetate complexes with neutral O-donor ligands, namely Ce2(OAc)(TFA)5(DMF)3 (1), Ce(TFA)3(L)x [x = 2, L = THF (2), DMF (3), DMSO (4); x = 1, L = diglyme (5)] and Ce2(TFA)6(DMSO)x(DMF)y [x = 6, y = 0 (6); x = 4, y = 2 (7)] (where OAc = acetate, TFA = trifluoroacetate, THF = tetrahydrofuran, DMF = dimethylformamide, DMSO = dimethylsulphoxide, and diglyme = MeO(C2H4O)2Me] were synthesized and completely characterized by elemental analysis, FT-IR spectroscopy and TG-DTA-MS studies. A partially hydrated complex [Ce(TFA)3(diglyme)(H2O)] (8) was obtained by slow evaporation of the THF solution of anhydrous 5 in the air. The single crystal X-ray diffraction analysis of 1, 3, 4, and 6–8 showed the versatile bonding mode of the TFA ligand (terminal, chelating and bridging). These complexes, on decomposition in 1-octadecene in inert atmosphere, gave CeF3 nanoparticles of 8–11 nm size. The complex 5 proved to be the best precursor in the series because of the ability of the diglyme ligand to act as capping reagent during decomposition to render the CeF3 particles monodisperse in organic solvents. The obtained CeF3 nanoparticles were characterized by FT-IR, EDX analysis and TEM studies and their luminescence and scintillation responses under UV and X-ray excitation were studied and compared with that of CeF3 single crystal.

A Facile Molecular Precursor‐based Synthesis of Ag2Se Nanoparticles and Its Composites with TiO2 for Enhanced Photocatalytic Activity

“…The trifluoroacetate ligand may bind to the metal center in an umber of fashions, and the asymmetric and symmetric vibrations of the CO 2 group can indicate its binding modes. [26] The appearance of only as ingle band at 1670 cm À1 for n as CO 2 is consistent with one type of TFAl igand present in 1,w hereas an overlap of the same absorption due to three different bonding modes of the TFAl igand resultsi nastrong broad band centered around 1680 cm À1 in 3 (Figure 1). The derivative 2 shows characteristicp eak(s) for the tBu 2 Se ligand only,a sm etal-iodide stretching usually appearsb elow 400 cm À1 .A se xpected, the 1 HNMR spectra of 1-3 in CDCl 3 / CD 2 Cl 2 are simple and show only as inglet at d = 1.57-1.95 ppm for the tBu/Me groups of the selenoethers.…”

Enhanced visible and near infrared emissions via Ce3+to Ln3+energy transfer in Ln3+-doped CeF3nanocrystals (Ln = Nd and Sm)

“…NIR luminescence of lanthanide ions (Ln 3+ ) finds applications in NIR LED technology, lasers, solar energy conversion, medical science and telecommunication. [1][2][3][4] For example, Ln 3+ ions such as Er 3+ , Nd 3+ , Tm 3+ and Ho 3+ have characteristic emissions in the NIR region and can be used as active materials for developing optical amplifiers. [5][6][7] In addition, NIR emission is quite valuable for biological applications because of lower scattering from the body than visible photons, low auto-fluorescence, deep penetration and being transparent to biological tissues.…”

Synthesis, characterization, and utility of trifluoroacetic acid lanthanide precursors for production of varied phase fluorinated lanthanide nanomaterials

“…[3,9,[22][23][24][25][26][27][28] The TFA adducts used in these experiments involved water-based [22,23,[25][26][27][28] derivatives. It has been reasoned that removal of the water may lead to improved properties [29] and numerous efforts have focused on exploiting organic modifiers (i.e., Lewis bases, crown ethers, etc.) in place of water.…”

“…in place of water. [29,30] While this has proven to be an acceptable approach, the inclusion of additional organic matter only seems to complicate the decomposition pathway. Therefore, we elected to study the non-modified H-TFA derivatives, following eq 1, in hopes of generating a series of "Ln(TFA) 3 The structural properties of these unusual compounds and attempts to convert them to LnF 3 by SOLVO methods were explored.…”

“…Ln (including Sc and Y) cation yields ~90 complexes, which is cut in half when the heteroleptic species are removed from this list [30]. Of these, only 14 compounds were reported that possess TFA and a bound solvent (not water): [Ce(-TFA) 2 (k 2 -TFA) 2 (solv) 3 ] 2 ,[29] (solv = DMSO; (DMSO) 2 (DMF)), [Ce(-TFA) 3 (solv) 2 ] n ,[29] (solv = "bipyridine, THF, phenanthroline, iso-propoxyethanol, ethanol, diglylme, pyridone, azacyclononanone, tetramethyldilane derivatives and other more complex organic species [30]. Since the inclusion of H 2 O or organic solvents add the potential for contamination in the final nanomaterials of interest,[49] it was reasoned that by synthesizing the TFA salts might allow for "cleaner" formation of the desired LnF 3 nanomaterial.…”