A Series of 3D Porous Lanthanide-Substituted Polyoxometalate Frameworks Based on Rare Hexadecahedral {Ln₆W₈O₂₈} Heterometallic Cage-Shaped Clusters

Abstract

are built from novel hexadecahedral {Ln 6 W 8 O 28 } heterometallic cage-shaped clusters. Intriguingly, every tetrameric {[Ln 3 (H 2 O) 3 (α-SiW 11 O 39 ) 2 ] 2 } 14− cage-cluster is linked with another eight tetrameric cage-clusters by Ln 3+ cations, leading to a novel 3D inorganic porous framework, which exhibits good thermal and chemical stability, excellent water vapor adsorption capacity, and moderate proton conductive properties. Furthermore, the solid state luminescence spectra demonstrate that 1-Sm, 1-Eu, 1-Tb, and 1-Dy display the lanthanide characteristic emission bands. The temperature-dependent magnetic susceptibility indicates that there are antiferromagnetic interactions in 1-Tb and 1-Dy.

Efficient Gas and VOC Separation and Pesticide Detection in a Highly Stable Interpenetrated Indium–Organic Framework

“…The VOC adsorption capacities of H 2 O, CH 3 OH, and C 2 H 5 OH for 1a were also investigated at 298 K under their corresponding vapor pressures ( P 0 = 3.00 kPa for H 2 O, 16.24 kPa for CH 3 OH, 7.43 kPa for C 2 H 5 OH). As a water-stabilized material, 1a displays a type V adsorption isotherm for H 2 O (Figure a), which is divided into three stages: before P / P 0 = 0.3, the amount of adsorption increases slowly; subsequently, a rapid growth in the adsorption is observed until P / P 0 = 0.7; then as P / P 0 continues to increase, the adsorption capacity gradually reaches saturation with a maximum loading of 218.6 cm 3 g –1 at P / P 0 ≈ 1, which is higher than the value for the recorded MOF 1-Gd (173.3 cm 3 g –1 ) . During the water adsorption process, an irreversible hysteresis loop between the adsorption and desorption branches is found.…”

“…As a water-stabilized material, 1a displays a type V adsorption isotherm for H 2 O (Figure 6a), which is divided into three stages: before P/P 0 = 0.3, the amount of adsorption increases slowly; subsequently, a rapid growth in the adsorption is observed until P/P 0 = 0.7; then as P/P 0 continues to increase, the adsorption capacity gradually reaches saturation with a maximum loading of 218.6 cm 3 −1 at P/P 0 ≈ 1, which is higher than the value for the recorded MOF 1-Gd (173.3 cm 3 g −1 ). 56 During the water adsorption process, an irreversible hysteresis loop between the adsorption and desorption branches is found. It is possible that the water molecules form hydrogen bonds with the amide groups in 1a, resulting in stronger host−guest interactions.…”

Organoamine-Directed Assembly of 5p–4f Heterometallic Cluster Substituted Polyoxometalates: Luminescence and Proton Conduction Properties

“…The fitting results show τ = 4.29 × 10 –4 s and A = 0.553 with an agreement factor of χ 2 = 1.058 for 1-Eu and τ = 4.38 × 10 –4 s and A = 0.043 with an agreement factor of χ 2 = 1.085 for 2-Eu . The emission spectrogram of 2-Tb obtained by using the excitation at 378 nm reveals four remarkable peaks at 489, 545, 582, and 614 nm, which can be ascribed to the 5 G 4 → 7 F J transition ( J = 6, 5, 4, and 3) of the Tb 3+ ion (Figure c) . Upon excitation at 452 nm, the emission spectrogram of 2-Dy reveals three prominent emission peaks appearing at 486, 572, and 658 nm, which correspond to 4 F 9/2 → 6 H J transmission ( J = 15/2, 13/2, and 11/2) (Figure d) .…”

“…The emission spectrogram of 2-Tb obtained by using the excitation at 378 nm reveals four remarkable peaks at 489, 545, 582, and 614 nm, which can be ascribed to the 5 G 4 → 7 F J transition (J = 6, 5, 4, and 3) of the Tb 3+ ion (Figure 3c). 31 Upon excitation at 452 nm, the emission spectrogram of 2-Dy reveals three prominent emission peaks appearing at 486, 572, and 658 nm, which correspond to 4 F 9/2 → 6 H J transmission (J = 15/2, 13/2, and 11/2) (Figure 3d). 59 The excitation spectra of 2-Tb and 2-Dy were measured by monitoring the maximum emission peak at 545 and 572 nm, respectively (Figure S15).…”

“…So far, a large number of transition-metal substituted polyoxometalates (TMSPs) with unique structures and interesting properties have been reported. − Researches on lanthanide-metal substituted polyoxometalates (LMSPs) have also been developed rapidly. A series of LMSPs containing lanthanide clusters have been synthesized, − and the highest nucleus Ln 27 was reported by our group . Recently, increasing interest and efforts have been devoted to the synthesis of TM-Ln heterometallic substituted POMs, and fascinating structures have been reported one after another. − However, through literature investigations, it can be found that reports on MG-Ln heterometallic substituted POMs are very limited and only several typical examples have been reported.…”