A molecular precursor approach to monodisperse scintillating CeF3 nanocrystals
Résumé
A series of anhydrous cerium(III) trifluoroacetate complexes with neutral O-donor ligands, namely Ce-2(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 Ce-2(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)(2)Me] 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.