All‐Inorganic Ionic Porous Material Based on Giant Spherical Polyoxometalates Containing Core‐Shell K₆@K₃₆‐Water Cage

Abstract

This work demonstrates that the use of high-negative and high-symmetry lacunary polyoxometalates (POMs) for the clustering of alkali metal ions is afeasible strategy not only for the formation of rare high-nuclearity alkali-metal clusters but also for the construction of new-type all-inorganic ionic porous materials.B yt he strategy,a nu nprecedented highnuclearity K-H 2 Ocluster {K 42 (H 2 O) 60 }with core-shell K 6 @K 36 configuration is stabilized by 8C 3v -symmetry trivacant POMs [GeW 9 O 34 ] 10À ,f orming an ovel giant ionic alkali-metal-POM composite cluster {K 42 Ge 8 W 72 O 272 (H 2 O) 60 }with more than 100 metal centers.T he incorporated 42-nuclearity K-H 2 Oc luster {K 42 (H 2 O) 60 }exhibits the highest-nuclearity alkali-metal-water cluster knownt od ate in POM chemistry.F urther,t he giant {K 42 Ge 8 W 72 O 272 (H 2 O) 60 }clusters can be linked by another kind of alkali metal ions Na + to generate af ascinating threedimensional all-inorganic ionic porous framework with high chemical stability,p roton conductivity,a nd water vapor adsorption.Figure 3. a) PXRD patterns of 1 after being soaked in water for 2hours at pH 2-12. b) Thermodiffractograms of the as-synthesized sample 1. c) Water vapor sorption isotherms (298 K) of 1.d)Nyquist plot for 1 under different RH conditionsw ith T = 30 8 8C. e) Nyquist plot of 1 under different temperatures with 98 %RH. f) Arrhenius plots of the proton conductivity of 1.

Self-Assembly of Giant Mo240 Hollow Opening Dodecahedra

“…As shown in Figure c, the proton conductivity increases with the increasing temperature. This should be attributed to possible promotion of H 3 O + ion formation (from H 2 O and H + ) at elevated temperatures and thus accelerate the proton transition within the channels. ,, At 80 °C and 98% RH, the proton conductivity reaches 1.03 × 10 –1 S cm –1 , which is the highest among the reported crystalline, POM-based proton conductors (Table S4) ,− and comparable to those of the high-performing metal–organic (MOF) and covalent–organic (COF) frameworks. ,,− Indeed, there are only a few MOFs and COFs, including BUT-8­(Cr)­A, PCMOF2 1/2 (Tz or Pz), IM-UiO-66-AS, and H 3 PO 4 @COFs, with proton conductivities on the order of 10 –1 S cm –1 under analogous conditions (Table S4). To investigate the conductivity stability of 1 , the proton conductivity was monitored for 24 h at 80 °C and 98% RH, and negligible change was noted (Figure S22).…”

“…At 25 °C and 98% RH, the proton conductivity of 1 reaches a maximum of 3.33 × 10 –2 S cm –1 , which is significantly higher than most known POM-based crystalline proton conductors under analogous conditions (Table S4). ,− The highly humidity-dependent proton conductivity implies that the water molecules play a significant role in conduction and that protons migrate primarily inside and outside of pores and channels in 1 . ,, As demonstrated by the room-temperature H 2 O vapor sorption measurement (Figure S18), 1 has an outstanding water uptake capacity under high humidities. This may facilitate the construction of hydrogen bond networks that can act as proton transport pathways within the channels of 1 , thus leading to outstanding conductivity. ,, …”

“…Furthermore, cage 1 shows high stability in solution and can be visualized by scanning transmission electron microscopy (STEM) and transmission electron microscopy (TEM) imaging. In addition, the bulk conductivities of 1·g reached 3.33 × 10 –2 S cm –1 at 25 °C and 98% relative humidity (RH) and 1.03 × 10 –1 S cm –1 at 80 °C and 98% RH, respectively, representing the highest among the reported POM-based crystalline proton conductors under the analogous conditions. ,− …”

Incorporating polyoxometalates and organic ligands to pursue 3d–4f heterometallic clusters: a series of {Cr4Ln4} clusters stabilized by phthalic acid and [SiW12O40]4−

“…35 The proton conduction in our materials is mainly carried out through hydrogen-bonding network among water molecules and protons, which is resulted from a combination of POMs, 3d-4f heterometalic clusters and organic species. 36,37 Conclusions A family of octanuclear 3d-4f heterometallic clusters, 1-Ln and 2-Ln, have been hydrothermally made. SCXRD structural analyses reveal that all compounds are constructed from novel Cr 4 Ln 4 cores stabilized by phthalic ligands and Keggin-type POMs.…”

Programming DNA‐Based Systems through Effective Molarity Enforced by Biomolecular Confinement

“…The predictable hybridization between complementary base pairs that underlies the self‐assembly of DNA lays the chemical foundation for engineering highly structured materials, dynamic nanodevices and complex reaction networks for molecular computation . Functional DNA nanotechnology has greatly benefited from the extensive use of programmable strand displacement reactions upholding the design of stimuli‐responsive DNA switches, enzyme‐free catalytic systems, or molecular computers .…”