“…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.…”
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.…”
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.
“…Among these linkers, lanthanide ions are normally excellent candidates for POM-based inorganic-organic hybrids (Li et al, 2017;. Due to their higher coordination number, more flexible coordination geometry and stronger oxophile ability, they have been prone to constructing high-dimensional architectures in the reported POM-based lanthanide complexes (Luo et al, 2018;Gao et al, 2010). Nevertheless, compared to these extended structures, the preparation of low-dimensional (especially discrete structure) hybrid materials is relatively difficult (Zhang et al, 2008).…”
Two POM‐based lanthanide derivatives, namely {triaqua[2,6‐diacetylpyridine bis(semicarbazone)‐κ5O,N,N′,N′′,O′]terbium(III)}‐μ‐oxido‐[tricosa‐μ2‐oxido‐dodecaoxido‐μ12‐phosphato‐dodecamolybdenum(VI)] pentahydrate (1), [Tb(C11H15N7O2)(H2O)3][PMo12O40]·5H2O, and the dysprosium(III) analogue (2), have been isolated successfully by the reaction of Keggin–POM [PMo12O40]3− (abbreviated as PMo12), the Ln3+ ion and the Schiff base 2,6‐diacetylpyridine bis(semicarbazone) (DAPSC) ligand under hydrothermal conditions. [Ln(DAPSC)(H2O)3][PMo12O40]·5H2O is a PMo12‐supported cluster featuring a lanthanide–Schiff base complex [denoted Ln–L(Schiff base)]. Single‐crystal X‐ray diffraction analysis reveals that the LnIII ion is in a distorted tricapped trigonal prismatic arrangement, coordinated by six O atoms and three N atoms. Two O atoms and three N atoms are provided by one DAPSC ligand, while the additional O atoms originate from a PMo12 cluster and three water molecules. Hydrogen‐bonding interactions between adjacent clusters form an interesting three‐dimensional supramolecular structure. The identities of 1 and 2 were characterized by IR spectroscopy, thermogravimetric analysis and powder X‐ray diffraction. Interestingly, both compounds possess excellent two‐photon absorption (TPA) responses to the third‐order nonlinear optics (NLO) (2264 GM for 1 and 941 GM for 2), suggesting that they have potential applications in the field of nonlinear optics (NLO). To our knowledge, 1 and 2 are the first POM‐based Ln–L(Schiff base) complexes showing excellent two‐photon responses. Meanwhile, the electrochemical properties of both compounds were studied in detail.
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