Synthesis, Structure, and Luminescence of Mixed-Ligand Lanthanide Trifluoroacetates

Abstract

A series of new mixed-ligand lanthanide trifluoroacetates of formula Ln­(4-cpno)­(tfa)3(H2O)·H2O (Ln = Sm, Eu, Gd, Tb, Dy; 4-cpno = 4-cyanopyridine N-oxide; tfa = trifluoroacetate) is reported. Trifluoroacetates were synthesized as chemically pure polycrystalline solids and their crystal structures were probed using single-crystal and powder X-ray diffraction. Ln­(4-cpno)­(tfa)3(H2O)·H2O solids make up an isostructural series in which LnO8 polyhedra are bridged by 4-cpno to form edge-sharing dimers. Trifluoroacetato connects these dimers to yield chains whose three-dimensional packing is governed by hydrogen bonds established between 4-cpno, trifluoroacetato, and water. 4-cpno serves as an efficient sensitizer of lanthanide-centered luminescence. UV excitation of its singlet manifold and subsequent energy transfer to the 4f levels of the lanthanides yield orange (Sm), red (Eu), green (Tb), and yellow (Dy) emissions. Sensitization efficiencies reach 81 and 64% for Eu and Tb hybrids, respectively. Tb­(4-cpno)­(tfa)3(H2O)·H2O displays a quantum yield of 52%, which coupled to the high absorptivity of 4-cpno, makes it a bright-green emitter under 292 nm excitation. Lanthanide trifluoroacetates may therefore serve as hybrid solid-state light emitters provided that adequate sensitizers are identified.

Synthesis of Metastable Silver-Lanthanide Double Perovskite Nanocrystals with White-Light Emission

“…Excitation of the host (336 nm) results in a much higher lanthanide emission than direct excitation of the Eu 3+ (395 nm, 5 L 6 ← 7 F 0 ), confirming an energy transfer process from STE to Eu 3+ ion (Figure S15). Such energy transfer further quenches the STE emission and leads to a low PLQY of 1.16% in Cs 2 AgEuCl 6 NCs, which is lower than other silver-lanthanide NCs.…”

N‐Pyridylureas as Masked Isocyanates Fort the Late‐Stage Diversification of Pyridine‐N‐Oxides

“…[13][14][15] They also are used for the mild oxidation of alkanes, [16] alkenes, [17] alkynes, [18][19][20] amides, [21] difluorocarbene, [22] silyl enol ethers, [23] ynamides, [24] and water. [25] In coordination chemistry, azine-N-oxides are utilized as ligands for the preparation of transition metal complexes manifested catalytic, [26,27] therapiutic, [28,29] luminescent, [30] and magnetic properties. [31][32][33] Moreover, many azine-N-oxides have valuable properties themselves.…”

Crystalline-to-semicrystalline transition in lanthanide trifluoroacetates: implications for optical pressure and temperature sensing

“…By contrast, when it comes to their light-emitting properties, only a handful of studies have been reported. [14][15][16][17][18][19][20][21] These reports probed the room-temperature photoluminescence of Ln(tfa) 3 (H 2 O) 3 as a means of elucidating structural details 14,[16][17][18] or of understanding the impact of organic sensitizers on lanthanide emission. 15,[19][20][21] The temperature dependence of the luminescence response of these materials has not been studied.…”

“…[14][15][16][17][18][19][20][21] These reports probed the room-temperature photoluminescence of Ln(tfa) 3 (H 2 O) 3 as a means of elucidating structural details 14,[16][17][18] or of understanding the impact of organic sensitizers on lanthanide emission. 15,[19][20][21] The temperature dependence of the luminescence response of these materials has not been studied. This is remarkable considering the widespread interest in identifying hybrid organic-inorganic platforms amenable to the design of lanthanide-based luminescent thermometers.…”