Synthesis, Structure, and Photoluminescence of Color-Tunable and White-Light-Emitting Lanthanide Metal–Organic Open Frameworks Composed of AlMo₆(OH)₆O₁₈^3– Polyanion and Nicotinate

Abstract

A series of isostructural compounds Na(HL)(CHCOO)Ln(Al(OH)MoO)(HO)·10HO [L = nicotinate; Ln = Eu (1), Tb (2)] and Na(HL)(CHCOO)EuTbLa(AlMo(OH)O)(HO)·10HO (3-8, L = nicotinate), wherein Anderson-type polyanions AlMo(OH)O as basic inorganic building blocks are connected by Eu(CHCOO)(HL)(HO)] and [Na(HO)] cations, resulting in formation of three-dimensional lanthanide metal-organic open frameworks, were synthesized successfully with AlCl·6HO, NaMoO·2HO, nicotinic acid, and lanthanide nitrates as starting materials. The compounds were characterized by UV-vis, IR, elemental analysis, powder XRD, and TG-DTA measurements. The single-crystal structures of compounds 1 and 2 show that the two compounds display three-dimensional open frameworks with 1D channels along the b and c axes. Investigation of the energy transfer mechanism indicated that the organic nicotinate ligand can transfer energy efficiently to Tb rather than Eu. The influence of the POM moiety on the fluorescence of the compounds is also studied. Compounds 1-8 exhibit tunable luminescence color, and emitting of white light was realized through adjusting the molar ratio of Eu:Tb:La within the compounds.

Luminescence Modulation, White Light Emission, and Energy Transfer in a Family of Lanthanide Metal–Organic Frameworks Based on a Planar π-Conjugated Ligand

“…Therefore, not only the different types of Ln 3+ ions can be incorporated into the same MOF but also the ratios of Ln 3+ ions in a MOF can be tuned by adjusting the adding amounts of Ln 3+ ions in reaction. − This fact suggests that the luminescent colors of Ln-MOFs can be tuned. Consequently, the doping of different Ln 3+ ions into isostructural MOFs has become a burgeoning and remarkable approach to produce white phosphor materials. − However, the related reports are presently very sporadic, the development of Ln-MOFs-based WLEDs achieved by controlling the doping amounts of different Ln 3+ ions is an appealing and important project.…”

A Series of New Eu/Tb Mixed MOFs with Tunable Color Luminescence

“…Among the many carboxylate ligands as linker in MOFs, oxalic acid, as a versatile O‐donor linker ligand, is the smallest dibasic acid, and widely used in the field of MOFs as a secondary building unit, having a strong coordination ability . However, by using oxalic acid as the main ligand to construct the Ln ‐MOFs, possessing good luminescence performance, is still sporadic . To best of our knowledge, the application of mixed Eu/Tb oxalate complexes for the fluorescence modulation has not been investigated …”

A Hybrid Materials Approach for Fabricating Efficient WLEDs Based on Di‐Ureasils Doped with Carbon Dots and a Europium Complex

“…[12] The most widely investigated materials are Ln 3+ -based organic-inorganic hybrids, [13,14] including metalorganic frameworks (MOFs), [15] because of their structural variety and stability. The primary blue component originates either from the organic ligands, or from Ln 3+ ions (alone, e.g., Dy 3+ [16] , or combined, Eu 3+ /Gd 3+ , [17] Eu 3+ /Tb 3+ , [18] Eu 3+ /Tb 3+ /Gd 3+ , [19] and Eu 3+ /Tb 3+ /La 3+ [20] ). However, WLEDs in which white light is generated from a single phase rather than by multiple emitting components (i.e., several layers comprising distinct phosphors), are the most desirable ones, as reabsorption of light is minimized, color alteration and a decrease of luminous efficiency are avoided, and the device is simplified.…”