Enhanced luminescence in ZnAlEu layered double hydroxides with interlamellar carboxylate and β-diketone ligands

Abstract

The physico-chemical properties of layered double hydroxides (LDHs) can be tailored to a large extent by exploiting the flexibility of their chemical composition. This report describes the synthesis and the detailed quantitative characterization of the luminescence properties of novel Eu 3+ -containing LDHs intercalated by carboxylate and β-diketonate anionic ligands. To prepare the samples, Zn 2+ , Al 3+ and Eu 3+ were coprecipitated in a ligand-rich solution containing 1,3,5benzenetricarboxylate (BTC), acetylacetonate (ACAC), and thenoyltrifluoroacetonate (TTA).Powder X-ray diffraction is supportive for the intercalation of BTC and ACAC. The presence of TTA is revealed by CHN quantification and by the photoluminescence results. Detailed spectroscopic investigation of these materials demonstrates quantum efficiencies (η) of 15 to 17% emerging from the symmetry reduction engendered by the organic ligands in the vicinity of

NMR Crystallography Reveals Carbonate Induced Al‐Ordering in ZnAl Layered Double Hydroxide

“…[2] Recently, even nanotubular, luminescent, and mixed ligand luminescent LDHs have been reported. [3][4][5] LDH structures are typically described in a rhombohedral or hexagonal crystal symmetry with three or two layers in a unit cell in the hexagonal crystal system. Usually, cation-disorder is assumed, treating cation sites of tri-and divalent ions as equivalent.…”

Coordination of Eu3+ Activators in ZnAlEu Layered Double Hydroxides Intercalated by Isophthalate and Nitrilotriacetate

“…The powder X-ray diffraction (PXRD) patterns of LDH-ISO and LDH-NTA ( Figure 2 ) confirm the formation of the LDH phase in both samples. 1 , 31 , 39 Their Bragg reflections can be indexed based on a three-layer hexagonal unit cell with rhombohedral centering. In the lower angle region, 2θ < 25°, the (00 l ) Bragg peaks of each pattern arise from the reflections coming from the basal planes passing through the metal sites in the hydroxide layers.…”

“…Similar conclusions have been drawn for the intercalation of other carboxylates and also for β-diketones. 31 …”

Uma Eficiente Síntese De Derivados De Triarilmetano

“…O processo térmico eleva o valor de Ω4 (2,1 para 13,6) da amostra (ZnAlEu-350 °C) mostrando a modificação na polarizabilidade dos ligantes na primeira esfera de coordenação do íon Eu 3+ . Já com o processo de reidratação o valor do Ω2 aumenta consideravelmente (ZnAlEu-350 °C-HBTC) e se aproxima do valor encontrado na literatura para esse material (ZnAlEu-BTC) (MORAIS et al, 2019). Esses resultados mostram a modificação no ambiente químico ao redor do íon Eu3+ nas diferentes etapas da reação.…”

“…Além das modificações apresentadas, o acréscimo do BTC através do processo de reidratação dobra o valor de eficiência quântica do material, indicando a efetiva intercalação do ligante no HDL reformado. O resultado encontrado para a amostra reidratada na presença da molécula fotossensibilizadora mostra que o material apresenta um rendimento quântico comparável àquela sintetizada por coprecipitação (ZnAlEu-BTC) (MORAIS et al, 2019).…”