“…The Tb-MOF lifetime was shown to have a monoexponential decay longer than that in the Eu-MOF (1057 µs vs. 600 ± 1 µs). On the other hand, both Eu and Tb-MOFs have predominantly exhibited longer lifetimes than the recently reported values 14 , 41 , 42 without modifying the structure with external fluorophores. Figure 4 Time-resolved emission decays of Eu-MOF (λ ex = 396 nm) and Tb-MOF (λ ex = 285 nm) with their corresponding lifetime values.…”
Section: Resultscontrasting
confidence: 66%
“…Particularly, after a literature search and screening, we choose and have successfully reproduced two Ln-MOFs (Ln = Eu and Tb) 27 and found that they exhibit interesting photoluminescent property. These are the first luminescent Ln oxalates that showed high phosphorescence quantum yields and very long phosphorescence lifetime compared to similar reported systems 13 , 14 , 28 . The solid-state photoluminescent intensity and the emission lifetime behaviour of Eu- and Tb-oxalate have been experimentally analysed and theoretically calculated using time-dependent density functional theory (TD-DFT).…”
Section: Introductionmentioning
confidence: 68%
“…As Ln metals are classically hard acids, they have high binding affinity to hard base donor atoms like oxygen or mixed atoms of oxygen and nitrogen. Polycarboxylate linkers are thus commonly used to construct Ln-MOFs 12 – 14 . Specifically, MOFs based on Ln oxalates have been studied due to their interesting optical and magnetic properties 15 which are employed in chemical thermal analysis 16 and nuclear chemistry 17 .…”
Two lanthanide metal–organic frameworks [Ln-MOFs, Ln = Eu(III), Tb(III)] composed of oxalic acid and Ln building units were hydrothermally synthesized and fully characterized by powder X-ray diffraction, Fourier-transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscope, and energy-dispersive X-ray spectroscopy. Furthermore, their magnetic susceptibility measurements were obtained using SQUID based vibrating sample magnetometer (MPMS 3, Quantum Design). Both Ln-MOFs exhibited highly efficient luminescent property. Solid-state photoluminescence (PL) measurements revealed phosphorescence emission bands of Eu-MOF and Tb-MOF centered at 618 nm (red emission) and 550 nm (green emission) upon excitation at 396 nm and 285 nm, respectively. Eu-MOF and Tb-MOF displayed a phosphorescence quantum yield of 53% and 40%, respectively. Time-resolved PL analyses showed very long lifetime values, at 600 and 1065 ± 1 µs for Eu-MOF and Tb-MOF, respectively. Calculations performed by density functional theory indicated a charge transfer form metal centres to the ligand which was in good agreement with the experimental studies. Therefore, this new mode of highly photoluminescent MOF materials is studied for the first time which paves the way for better understanding of these systems for potential applications.
“…The Tb-MOF lifetime was shown to have a monoexponential decay longer than that in the Eu-MOF (1057 µs vs. 600 ± 1 µs). On the other hand, both Eu and Tb-MOFs have predominantly exhibited longer lifetimes than the recently reported values 14 , 41 , 42 without modifying the structure with external fluorophores. Figure 4 Time-resolved emission decays of Eu-MOF (λ ex = 396 nm) and Tb-MOF (λ ex = 285 nm) with their corresponding lifetime values.…”
Section: Resultscontrasting
confidence: 66%
“…Particularly, after a literature search and screening, we choose and have successfully reproduced two Ln-MOFs (Ln = Eu and Tb) 27 and found that they exhibit interesting photoluminescent property. These are the first luminescent Ln oxalates that showed high phosphorescence quantum yields and very long phosphorescence lifetime compared to similar reported systems 13 , 14 , 28 . The solid-state photoluminescent intensity and the emission lifetime behaviour of Eu- and Tb-oxalate have been experimentally analysed and theoretically calculated using time-dependent density functional theory (TD-DFT).…”
Section: Introductionmentioning
confidence: 68%
“…As Ln metals are classically hard acids, they have high binding affinity to hard base donor atoms like oxygen or mixed atoms of oxygen and nitrogen. Polycarboxylate linkers are thus commonly used to construct Ln-MOFs 12 – 14 . Specifically, MOFs based on Ln oxalates have been studied due to their interesting optical and magnetic properties 15 which are employed in chemical thermal analysis 16 and nuclear chemistry 17 .…”
Two lanthanide metal–organic frameworks [Ln-MOFs, Ln = Eu(III), Tb(III)] composed of oxalic acid and Ln building units were hydrothermally synthesized and fully characterized by powder X-ray diffraction, Fourier-transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscope, and energy-dispersive X-ray spectroscopy. Furthermore, their magnetic susceptibility measurements were obtained using SQUID based vibrating sample magnetometer (MPMS 3, Quantum Design). Both Ln-MOFs exhibited highly efficient luminescent property. Solid-state photoluminescence (PL) measurements revealed phosphorescence emission bands of Eu-MOF and Tb-MOF centered at 618 nm (red emission) and 550 nm (green emission) upon excitation at 396 nm and 285 nm, respectively. Eu-MOF and Tb-MOF displayed a phosphorescence quantum yield of 53% and 40%, respectively. Time-resolved PL analyses showed very long lifetime values, at 600 and 1065 ± 1 µs for Eu-MOF and Tb-MOF, respectively. Calculations performed by density functional theory indicated a charge transfer form metal centres to the ligand which was in good agreement with the experimental studies. Therefore, this new mode of highly photoluminescent MOF materials is studied for the first time which paves the way for better understanding of these systems for potential applications.
“…By monitoring the strongest emissions of the lanthanide ions, all excitation spectra recorded for 3, 5 and 6 exhibit similar broad bands (250-350 nm) and narrow f-f transitions. [32] The broad bands correspond to the π-π* transitions of the organic ligands. The peak values of the organic ligands are slightly stronger than those of the lanthanide ions, implying the organic ligands can sensitize the luminescence of the lanthanide ions in these three complexes.…”
A series of 3d–4f heterometallic complexes, namely [Ln2Co2(2,3‐DCB)10(phen)2] [Ln=Nd (1), Sm (2), Eu (3), Gd (4), Tb (5), Dy (6), Er (7)], were obtained through the self‐assembly reactions of Ln(NO3)3 ⋅ nH2O, Co(NO3)2 ⋅ 6H2O, 2,3‐dichlorobenzoic acid (2,3‐HDCB), NaOH and 1,10‐phenanthroline (phen) under solvothermal conditions. Their crystal structures were determined by single‐crystal X‐ray diffraction. They were also characterized by elemental analysis, FT‐IR, powder X‐ray diffraction (PXRD) and thermogravimetric analysis (TGA) and differential thermoanalysis (DTA). These seven complexes have the same molecular formula but different crystal structures. Complexes 1–3, 4 and 5 as well as 6 and 7 are crystallographically isomorphous, respectively. They all exhibit zero‐dimensional (0D) linear tetranuclear cluster structures. These 0D linear tetranuclear clusters can be further connected into a two‐dimensional (2D) supramolecular network via the extensive intermolecular π–π interactions between 2,3‐DCB and phen. The photoluminescent properties of 3, 5 and 6 and the magnetic properties of 1–2 and 4–7 were investigated. Complex 6 shows a slow magnetic relaxation behavior.
“…Actually, a number of ox-involving emissive Eu 3+ compounds were found in the literature. 28,29 Another aspect of interest may reside in fixing CO 2 . A carbonate ion plays a role of a template to the Eu 3+ array in 1, or in other words, the carbonate ion is fixed as a multidentate ligand.…”
A new luminescent lanthanide coordination polymer composed of europium(III), oxalate and carbonate was prepared. A hydrothermal technique was applied to an aqueous solution of europium(III) nitrate and oxalic acid (H2ox)...
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