Terbium-fluorido cluster: an energy cage for photoluminescence

Abstract

<p>This work demonstrates that encapsulating terbium ions into a fluorido-bridged cage by organic ligands significantly enhances the luminescence quantum yield of such sub-nanosized materials.</p>

Oxidation of europium with ammonium perfluorocarboxylates in liquid ammonia: pathways to europium(ii) carboxylates and hexanuclear europium(iii) fluoridocarboxylate complexes

“…[44] Ling et al observed that fluoride ions hardly contribute to nonradiative relaxation of the excited states of Tb III in a complex with a [Tb6F8] core due to their low vibrational energy and expanding the luminescence decay time compared to polynuclear terbium(III) hydroxido complexes. [21] This is consistently confirmed for complexes with a [Eu6F8] core within this work.…”

“…S17, ESI †); (iv) there is a very recent example of a complex of the type [Tb6F8] in literature, with pivalic acid as a carboxylate ligand. [21] Crystal perfluorocarboxylates. [12][13] Smaller O-C-O' angles of about 120° would be typical for the tridentate-chelating and -bridging (µ2-O:O',O) mode often found in lanthanoid(III) acetates.…”

“…Based on the products of oxidation in liquid ammonia we succeeded in the synthesis and characterization of a solvated europium( ii ) trifluoroacetate 1 , and in the further oxidation by perfluorocarboxylic acids to hexanuclear europium complexes, (NH 4 ) 2 [Eu 6 F 8 (O 2 CR) 12 (RCOOH) 6 ], with R = CF 3 ( 2 ) and R = C 2 F 5 ( 3 ). To the best of our knowledge, compounds 1 , 2 and 3 are the first Eu II perfluorocarboxylate and the first Eu III derivatives of hexanuclear Ln III fluoridocarboxylates, 21 respectively.…”

The Long and Bright Path of a Lanthanide MOF: From Basics towards the Application

“…Ling et al. reported that terbium complexes exhibit an increase in the emission intensity when aquo ligands are replaced by F − ligands [27] . The reported quantum yield (QY) values for aquo coordinated terbium clusters are below 30 %, but the authors reported a QY of 99.6 % for the fluoride coordinated clusters.…”

“…The "Dissolution" region reflects the irreversible transformation of the Tb-BTC structure and the formation of TbF 3 ,a sp reviously observed by EXAFS. The decrease in the emission is due to the low QY of TbF 3 [27] (QY TbF3 = 15 %) respectt ot he other Tb-BTC speciespresentinthe system as observedi nFigure 3D.The resulting emission can be assumed as the weighted averaged contribution of each component;t he TbF 3 produced by the transformation of the Tb-BTC structure in presence of fluorides and the correspondingf rom the unreacted Tb-BTC: I measured = X TbF3 I TbF3 + X Tb-BTC I Tb-BTC ,w here X are the fraction of each component and I,t he emission intensity of each component. Even though the mechanism is relatedt ot he quenching emission of Tb ions, the process occurs in solid state and it is different from quenching mechanism in solution involving the Stern-Volmer mechanism.…”