Reduction-Induced Uptake of Cs+ in Metal-Organic Frameworks Loaded with Polyoxometalates.

Materials for Cs+ adsorption continue to be important for the treatment of various solutions. Metal-organic frameworks (MOFs) with large specific surface areas promise adsorption properties for various gases, vapors, and ions. However, the utilization of MOFs for alkali ion capture, specifically, Cs+ capture is still in its infancy. Herein, MOFs are hybridized with polyoxometalates (POMs) to study the effect of i) MOF type, ii) POM type, and iii) POM loading amounts on Cs+ capture. In particular, the composite of ZIF-8 and [α-PMo12O40]3- (PMo12/ZIF-8) adsorbed Cs+ ions effectively when compared to pristine ZIF-8. In addition, the reduction of Mo within the POM from MoVI to MoV by ascorbic acid during the Cs+ uptake process doubled the Cs+ uptake capacity of PMo12/ZIF-8. This observation can be attributed to the increased overall negative charge of the POM facilitating Cs+ uptake to compensate for the charge imbalance. Hybridization with other MOFs (MIL-101 and UiO-66) largely suppresses the Cs+ uptake, highlighting the importance of hydrophobicity in Cs+ capture. Furthermore, PMo12/ZIF-8 led to an outstanding Cs+ uptake (291.5 mg g-1) with high selectivity (79.6%) from quinary mixtures of alkali metal cations even among other representative porous materials (Prussian blue and zeolites).

Small luminescent silver clusters stabilized in porous crystalline solids.

Subnanometric or small metal clusters (SMCs) have been extensively researched due to their unique electronic, optical, catalytic, and magnetic properties, which differ from those of bulk samples. Among the SMCs, silver (Ag) clusters have received significant interest due to their affordability and unique luminescent properties. Currently, two major approaches, gas-phase and liquid-phase synthesis, have been employed to obtain Ag clusters with precise control of size and structure. More recently, attention has been directed toward the utilization of porous crystalline solids such as metal-organic frameworks (MOFs), zeolites, and porous ionic crystals (PICs) to synthesize and stabilize Ag clusters. In this review, we aim to provide a comprehensive overview of the synthesis, structures, and luminescent properties of Ag clusters in porous crystalline solids.

Size-Controlled Synthesis of Luminescent Few-Atom Silver Clusters via Electron Transfer in Isostructural Redox-Active Porous Ionic Crystals.

Ag clusters with a controlled number of atoms have received significant interest because they show size-dependent catalytic, optical, electronic, or magnetic properties. However, the synthesis of size-controlled, ligand-free, and air-stable Ag clusters with high yields has not been well-established. Herein, it is shown that isostructural porous ionic crystals (PICs) with redox-active polyoxometalates (POMs) can be used to synthesize Ag clusters via electron transfer from POMs to Ag+ . Ag clusters with average numbers of three, four, or six atoms emitting blue, green, or red colors, respectively, are formed and stabilized in the PICs under ambient conditions without any protecting ligands. The cluster size solely correlates with the degree of electron transfer, which is controlled by the reduction time and types of ions or elements of the PICs. Thus, advantages have been taken of POMs as electron sources and PICs as scaffolds to demonstrate a convenient method to obtain few-atom Ag clusters.

A Macrocyclic Polyoxomolybdate with Phosphate and Phosphonate Linkers: Synthesis, Structure, and Proton Conductivity.

A coordination macrocycle composed of eight identical [PMo8O27]- ({PMo8}) clusters connected by both organic tetraphosphonates and inorganic phosphates, (C3N2H5)29(NH4)6H12[(PMo8O27)8(C10P4O12N2H20)4(PO4)4Cs(Mo4O10(H2O)4)] (C3N2H5+ = imidazolium), is presented here. The primary building block, {PMo8}, is a tetravacant Keggin-type phosphomolybdate that has never been observed before. The compound shows a high proton conductivity of 9.70 × 10-3 S cm-1 at 373 K and 98% relative humidity. Control experiments on an imidazolium-free sample demonstrate the critical role of the imidazolium counterions as mobile proton carriers. The contribution of imidazolium necessitates a high activation energy (Ea = 0.502 eV) for proton conduction via the vehicle mechanism.

Oxygen Evolution Reaction Driven by Charge Transfer from a Cr Complex to Co-Containing Polyoxometalate in a Porous Ionic Crystal.

Considerable efforts have been devoted to developing oxygen evolution reaction (OER) catalysts based on transition metal oxides. Polyoxometalates (POMs) can be regarded as model compounds of transition metal oxides, and cobalt-containing POMs (Co-POMs) have received significant interest as candidates. Nanocomposites based on Co-POMs have been reported to show high OER activities due to synergistic effects among the components; however, the role of each component is unclear due to its complex structure. Herein, we utilize porous ionic crystals (PICs) based on Co-POMs, which enable a composition-structure-function relationship to be established to understand the origin of the synergistic catalysis. Specifically, a Keggin-type POM [α-CoW12O40]6- and a Cr complex [Cr3O(OOCCH2CN)6(H2O)3]+ are implemented as PIC building blocks for the OER under nonbasic conditions. The potentially OER-active but highly soluble [α-CoW12O40]6- was successfully anchored in the crystalline PIC matrix via Coulomb interactions and hydrogen bonding induced by polar cyano groups of the Cr complex. The PIC exhibits efficient and sustained OER catalytic activity, while each building block is inactive. The Tafel slope of the linear sweep voltammetry curve and the relatively large kinetic isotope effect value suggest that elementary steps closely related to the OER rate involve single-electron and proton transfer reactions. Electrochemical and spectroscopic studies clearly show that the synergistic catalysis originates from the charge transfer from the Cr complex to [α-CoW12O40]6-; the increased electron density of [α-CoW12O40]6- may increase its basicity and accelerate proton abstraction as well as enhance electron transfer to stabilize the reaction intermediates adsorbed on [α-CoW12O40]6-.

Macrocyclic Polyoxometalates: Selective Polyanion Binding and Ultrahigh Proton Conduction.

The rational development of an anion templation strategy for the construction of macrocycles has been historically limited to small anions, but large polyoxoanions can offer unmatched structural diversity and ample binding sites. Here we report the formation of a {Mo22 Fe8 } macrocycle by using the Preyssler anion, [NaP5 W30 O110 ]14- ({P5 W30 }), as a supramolecular template. The {Mo22 Fe8 } macrocycle displays selective anion binding behavior in solution. In the solid state, the 1 : 2 host-guest complex, {P5 W30 }2 ⊂{Mo22 Fe8 }, transports protons more effectively, through an extended hydrogen-bonding network, than a related 1 : 1 complex where the guest is completely encapsulated. The results highlight the great potential this anion templation approach has in producing macrocyclic systems for selective anion recognition and proton conduction purposes.

Amorphous High-Surface-Area Aluminum Hydroxide-Bicarbonates for Highly Efficient Methyl Orange Removal from Water.

Amorphous high-surface-area aluminum hydroxide-bicarbonates were synthesized starting from AlCl3, base, and bicarbonate in water. Composites with a chemical formulas of [Al13O4(µ-OH)24(H2O)6.5(OH)5.5](HCO3)1.5 (I-NaOH) and [Al13O4(µ-OH)24(H2O)6(OH)6](HCO3) (I-NH3) were obtained by the use of NaOH/NaHCO3 and NH3/NH4HCO3 as base/bicarbonate, respectively. The surface area of the composites was highly dependent on the pH level of the synthetic solution, and composites with high surface areas (ca. 200 m2 g-1) were obtained around pH 7-8. Pore-size distributions determined from the N2 adsorption isotherms showed that I-NH3 and I-NaOH possess mainly large (pore radius rp > 3 nm) and small (rp < 3 nm) pores, respectively, despite similar surface areas. While SEM images showed that both I-NH3 and I-NaOH were aggregates of nanoparticles, the particles were more fused in I-NaOH, which is in line with the existence of small pores and the use of a stronger base (NaOH), which would facilitate the dehydration condensation reaction. The composites were applied as adsorbents to remove methyl orange (MO) from water. The time course of MO adsorption was readily fitted with a pseudo-second-order model, and over 90% MO removal was attained within 10 min with I-NH3, while I-NaOH showed much less MO removal (26%). The MO adsorption isotherm of I-NH3 was reproduced with a Langmuir model with an adsorption capacity of 154 mg g-1. Notably, the aluminum hydroxide-bicarbonates could not absorb methylene blue, which is a cationic dye, while anions (MO and PO43-) were readily absorbed. Solid-state 27Al MAS NMR spectra showed that the concentration of 5-coordinated aluminum species, which may serve as guest binding sites, was higher for I-NH3. These results show that electrostatic interaction between anionic MO and coordinatively unsaturated 5-coordinated cationic aluminum species and the large external surface area of I-NH3 contribute to the highly efficient MO adsorption.

Selective Convergence to Atropisomers of a Porphyrin Derivative Having Bulky Substituents at the Periphery.

Four kinds of possible atropisomers of a porphyrin derivative (1), having mesityl groups at one of the o-positions of each meso-aryl group, can be selectively converged to targeted atropisomers among the four isomers (αααα, αααß, αßαß, and ααßß) under appropriate conditions for each atropisomer. For example, protonation and subsequent neutralization of a free base porphyrin (H2-1) induces a convergence reaction to the αßαß atropisomer, H2-1-αßαß, from an atropisomeric mixture. The αααα isomer, H2-1-αααα, was also obtained by heating a solution of H2-1 in CHCl3 in 60% isolated yield, probably owing to a template effect of the solvent molecule. Remarkably, when an atropisomeric mixture of its zinc complex, Zn-1, was heated at 70 °C in a ClCH2CH2Cl/MeOH mixed solvent, crystals composed of only Zn-1-αααα were formed. The hydrophobic space formed by the four mesityl groups in the αααα isomer can be used for repeatable molecular encapsulation of benzene, and the encapsulation structure was elucidated by powder X-ray diffraction analysis. Heating the solid of an atropisomeric mixture of Zn-1 to 400 °C afforded the ααßß isomer almost quantitatively. On the other hand, the solid of H2-1-αααα can be converted by heating, successively to H2-1-αααß at 286 °C and then to H2-1-ααßß at 350 °C.

The orientation of a decellularized uterine scaffold determines the tissue topology and architecture of the regenerated uterus in rats†.

A decellularized uterine scaffold (DUS) prepared from rats permits recellularization and regeneration of uterine tissues when placed onto a partially excised uterus and supports pregnancy in a fashion comparable to the intact uterus. The underlying extracellular matrix (ECM) together with an acellular, perfusable vascular architecture preserved in DUS is thought to be responsible for appropriate regeneration of the uterus. To investigate this concept, we examined the effect of the orientation of the DUS-preserving ECM and the vascular architecture on uterine regeneration through placement of a DUS onto a partially defective uterine area in the reversed orientation such that the luminal face of the DUS was outside and the serosal face was inside. We characterized the tissue structure and function of the regenerated uterus, comparing the outcome to that when the DUS was placed in the correct orientation. Histological analysis revealed that aberrant structures including ectopic location of glands and an abnormal lining of smooth muscle layers were observed significantly more frequently in the reversed group than in the correct group (70% vs. 30%, P < 0.05). Despite the changes in tissue topology, the uteri regenerated with an incorrectly oriented DUS could achieve pregnancy in a way similar to uteri regenerated with a correctly oriented DUS. These results suggest that DUS-driven ECM orientation determines the regenerated uterus structure. Using DUS in the correct orientation is preferable when clinically applied. The disoriented DUS may deteriorate the tissue topology leading to structural disease of the uterus even though the fertility potential is not immediately affected.

Rapid Uptake/Release of Cs+ in Isostructural Redox-Active Porous Ionic Crystals with Large-Molecular-Size and Easily Reducible Dawson-Type Polyoxometalates as Building Blocks.

Isostructural redox-active ionic crystals were synthesized with large-molecular-size and easily reducible α-Dawson-type polyoxometalates [α-P2M18O62]6- (M = Mo and W) as building blocks. The crystals possess large closed pores and show rapid (1 h) and large amounts (5.5 or 4.4 mol mol-1) of Cs+ uptake at room temperature via reduction of the polyoxometalates. The reduced compounds can be fully oxidized, and Cs+ is released within 10 min.

Porous Cubic Cesium Salts of Silicododecatungstate(molybdate)/Borododecatungstate Blends: Synthesis and Molecular Adsorption Properties.

In this work, the synthesis and molecular adsorption properties of cubic cesium salts of Keggin-type silicododecametalates (SiM; M = W or Mo) and borododecatungstate (BW) blends were reported. Pentavalent BW, which is normally packed in a monoclinic fashion, could be packed into the desired cubic fashion by being blended with tetravalent SiW or SiMo. By simply mixing aqueous solutions containing SiM and BW in different SiM:BW molar ratios [SiM:BW = N:(100 - N), where N is the percentage of SiM in the synthetic solution and equals 100, 80, 50, 30, 20, 10, or 5] with a cesium nitrate solution, we obtained a series of cubic cesium salts (CsSiMBW- N) with POM vacancy-like pores (i.e., kinetically formed interparticle pores). Notably, the yields, compositions, and BET surface areas of the obtained CsSiMBW- N were dependent on only the N values and independent of SiW or SiMo. In CsSiMBW- N, SiM and BW were well blended at the molecular (nanometer) level. The nitrogen, water, and ethanol adsorption properties of CsSiWBW- N systematically changed according to the SiW:BW molar ratios. In the case of SiW-rich salts, nitrogen, water, and ethanol were adsorbed in the pores; the amounts of nitrogen, water, and ethanol adsorbed were nearly identical for CsSiWBW-100. When the SiW:BW molar ratio was decreased, the salts selectively incorporated water and ethanol within the pores. In the case of CsSiWBW-5, barely any nitrogen was adsorbed. The plausible mechanisms for particle growth and interparticle POM vacancy-like pore formation are also discussed.

Solid-State Umbrella-type Inversion of a VO5 Square-Pyramidal Unit in a Bowl-type Dodecavanadate Induced by Insertion and Elimination of a Guest Molecule.

Design of cavities for a target molecule and the elucidation of the corresponding host-guest interactions are important for molecular manipulation. A discrete dodecavanadate bowl, [V12 O32 ]4- (V12), with an entrance diameter of 4.4 Šand an electron-rich guest at the center of the bowl, was stabilized by electrostatic interactions. A characteristic of V12 is a solid-state polytopal rearrangement during guest elimination and recapture. A guest-free dodecavanadate, [V12 O32 ]4- (V12-free), was prepared by removal of the guest from CH2 Cl2 -inserted V12 under vacuum at 50 °C. Single-crystal X-ray analysis revealed that one of the VO5 square pyramids at the bottom of V12-free was inverted to fill the void of the bowl cavity. The exposure of V12-free to the guest molecule vapors of CH2 Cl2 , 1,2-dichloroethane, MeNO2 , MeCN, and MeBr resulted in the selective insertion of the guest to reform the guest-inserted V12 structure. Whereas CO2 could be inserted in the V12 bowl, CH4 and CO could not.

High Proton Conduction in Crystalline Composites Based on Preyssler-Type Polyoxometalates and Polymers under Nonhumidified or Humidified Conditions.

Keggin-type polyoxometalate (POM)-based compounds have long been considered as one of the environmentally friendly candidates of solid electrolytes exhibiting high proton conductivity under high relative humidity (RH >95%). However, their application has been limited by the lack of structural stability and large decrease in conductivity with a slight decrease in RH. In order to overcome these disadvantages, we report a series of crystalline composites based on Preyssler-type POMs ([Na(H2O)P5W30O110]14-, [Bi(H2O)P5W30O110]12-), which are known to show higher acidity in comparison to Keggin-type POMs, and polymers (polyethylene glycol (PEG), polyallylamine (PAA)). Electrostatic interactions between POMs and polymers contribute to enhance the structural stability, and it has been widely known that polymer electrolytes promote cation transport via segmental motion of the polymer chain. In the crystalline composites, K+ acts as a linker to connect the POMs three-dimensionally, resulting in an all-inorganic framework, and polymers and waters of crystallization reside in the framework. The composites with PEG exhibit moderate proton conductivities of 10-4 S cm-1 under nonhumidified (RH <10%) and low-temperature (<368 K) conditions by the aid of segmental motion of PEG. The composite with PAA exhibits a high proton conductivity of 10-3 S cm-1 under humidified (RH 75%) and low-temperature (<338 K) conditions.

Proton conduction in alkali metal ion-exchanged porous ionic crystals.

Proton conduction in alkali metal ion-exchanged porous ionic crystals A2[Cr3O(OOCH)6(etpy)3]2[α-SiW12O40]·nH2O [I-A+] (A = Li, Na, K, Cs, etpy = 4-ethylpyridine) is investigated. Single crystal and powder X-ray diffraction measurements show that I-A+ possesses analogous one-dimensional channels where alkali metal ions (A+) and water of crystallization exist. Impedance spectroscopy and water diffusion measurements of I-A+ show that proton conductivities are low (10-7-10-6 S cm-1) under low relative humidity (RH), and protons mostly migrate as H3O+ with H2O as vehicles (vehicle mechanism). The proton conductivity of I-A+ increases with the increase in RH and is largely dependent on the types of alkali metal ions. I-Li+ shows a high proton conductivity of 1.9 × 10-3 S cm-1 (323 K) and a low activation energy of 0.23 eV under RH 95%. Under high RH, alkali metal ions with high ionic potentials (e.g., Li+) form a dense and extensive hydrogen-bonding network of water molecules with mobile protons at the periphery, which leads to high proton conductivities and low activation energies via rearrangement of the hydrogen-bonding network (Grotthuss mechanism).

Impact of borderline-subclinical hypothyroidism on subsequent pregnancy outcome in women with unexplained recurrent pregnancy loss.

AIM: Because subclinical hypothyroidism (thyroid-stimulating hormone [TSH] > 4.5 IU/mL) is associated with adverse pregnancy outcome, including early pregnancy loss, TSH is recommended to be titrated to ≤2.5 mIU/L in levothyroxine-treated women before pregnancy. The purpose of this study was to determine whether borderline-subclinical hypothyroidism (borderline-SCH; 2.5 < TSH ≤ 4.5 IU/mL) affects the outcome of subsequent pregnancies in women with unexplained recurrent pregnancy loss (uRPL). METHODS: After workup for antinuclear antibody (ANA), anti-phospholipid syndrome, thrombophilia, uterine abnormalities, hormone disorders, and/or chromosomal abnormalities, 317 women with a history of uRPL were enrolled. The women were classified into two groups: borderline-SCH, and euthyroidism (0.3 ≤ TSH ≤ 2.5 IU/mL). All women had normal serum free thyroxine (T4) and did not receive levothyroxine before or during the subsequent pregnancy. RESULTS: There were no significant differences in age, number of previous pregnancy losses, number of live births, or body mass index between the borderline-SCH (n = 56) and the euthyroid (n = 261) groups, but the rate of ANA positivity differed significantly (53.6% vs 33.7%, respectively; P = 0.005). The subsequent pregnancy rate did not differ between the two groups (55.4%, 31/56 vs 51.3%, 134/261, respectively). The pregnancy loss rate (<22 weeks of gestation) tended to be higher in the borderline-SCH than the euthyroid group (29.0%, 9/31 vs 17.9%, 24/134), although not significantly so (P = 0.16). CONCLUSIONS: Although some subset of uRPL is though to be due to as-yet-unidentified cause(s), borderline-SCH is unlikely to be involved in uRPL.

Conductive Hybrid Crystal Composed from Polyoxomolybdate and Deprotonatable Ionic-Liquid Surfactant.

A polyoxomolybdate inorganic-organic hybrid crystal was synthesized with deprotonatable ionic-liquid surfactant. 1-dodecylimidazolium cation was employed for its synthesis. The hybrid crystal contained δ-type octamolybdate (Mo8) isomer, and possessed alternate stacking of Mo8 monolayers and interdigitated surfactant bilayers. The crystal structure was compared with polyoxomolybdate hybrid crystals comprising 1-dodecyl-3-methylimidazolium surfactant, which preferred ß-type Mo8 isomer. The less bulky hydrophilic moiety of the 1-dodecylimidazolium interacted with the δ-Mo8 anion by N-H···O hydrogen bonds, which presumably induced the formation of the δ-Mo8 anion. Anhydrous conductivity of the hybrid crystal was estimated to be 5.5 × 10(-6) S·cm(-1) at 443 K by alternating current (AC) impedance spectroscopy.

Reduction-Induced Highly Selective Uptake of Cesium Ions by an Ionic Crystal Based on Silicododecamolybdate.

Cation adsorption and exchange has been an important topic in both basic and applied chemistry relevant to materials synthesis and chemical conversion, as well as purification and separation. Selective Cs(+) uptake from aqueous solutions is especially important because Cs(+) is expensive and is contained in radioactive wastes. However, the reported adsorbents incorporate Rb(+) as well as Cs(+) , and an adsorbent with high selectivity toward Cs(+) has not yet been reported. Highly selective uptake of Cs(+) by an ionic crystal (etpyH)2 [Cr3O(OOCH)6 (etpy)3]2 [α-SiMo12 O40 ]⋅3 H2O (etpy =4-ethylpyridine) is described. The compound incorporated up to 3.8 mol(Cs(+) ) mol(s)(-1) (where s=solid) by cation-exchange with etpyH(+) and reduction of silicododecamolybdate with ascorbic acid. The amount of Cs(+) uptake was comparable to that of Prussian blue, which is widely recognized as a good Cs(+) adsorbent. Moreover, other alkali-metal and alkaline-earth-metal cations were almost completely excluded (<0.2 mol mol(s)(-1)).

CD34 and CD49f Double-Positive and Lineage Marker-Negative Cells Isolated from Human Myometrium Exhibit Stem Cell-Like Properties Involved in Pregnancy-Induced Uterine Remodeling.

Repeated and dramatic pregnancy-induced uterine enlargement and remodeling throughout reproductive life suggests the existence of uterine smooth muscle stem/progenitor cells. The aim of this study was to isolate and characterize stem/progenitor-like cells from human myometrium through identification of specific surface markers. We here identify CD49f and CD34 as markers to permit selection of the stem/progenitor cell-like population from human myometrium and show that human CD45(-) CD31(-) glycophorin A(-) and CD49f(+) CD34(+) myometrial cells exhibit stem cell-like properties. These include side population phenotypes, an undifferentiated status, high colony-forming ability, multilineage differentiation into smooth muscle cells, osteoblasts, adipocytes, and chondrocytes, and in vivo myometrial tissue reconstitution following xenotransplantation. Furthermore, CD45(-) CD31(-) glycophorin A(-) and CD49f(+) CD34(+) myometrial cells proliferate under hypoxic conditions in vitro and, compared with the untreated nonpregnant myometrium, show greater expansion in the estrogen-treated nonpregnant myometrium and further in the pregnant myometrium in mice upon xenotransplantation. These results suggest that the newly identified myometrial stem/progenitor-like cells influenced by hypoxia and sex steroids may participate in pregnancy-induced uterine enlargement and remodeling, providing novel insights into human myometrial physiology.

Serum estradiol level during withdrawal bleeding as a predictive factor for intermittent ovarian function in women with primary ovarian insufficiency.

The objective of this study was to assess the potential predictive factors for follicle growth, ovulation, and pregnancy rate in patients with primary ovarian insufficiency/premature ovarian failure (POI/POF). We enrolled 25 POI patients with desired fertility who were treated and monitored for a minimum of 7 months between the years of 2000-2009 into this retrospective study. The clinical, endocrinologic, chromosomal, and autoimmunologic parameters of these patients were collected. Furthermore, hormonal backgrounds on each of 620 treatment cycles were investigated. The main outcome measures were follicle growth, ovulation, and pregnancy rate. Four of 25 patients (16%) conceived while being monitored and undergoing treatment. Follicle growth, ovulation, and pregnancy rate were not significantly different as a function of parity, iatrogenic history (e.g., chemotherapy), age of disease onset, serum estradiol (E(2))/follicle stimulating hormone (FSH) level at the time of diagnosis, chromosomal abnormality, and positive autoantibody titer. The serum E2 levels on days 1-5 of withdrawal bleeding (Day 1-5 E(2)) were significantly higher in the cycles with successful follicle growth and ovulation than unsuccessful cycles (P<0.05). Receiver-operator characteristic curve analysis revealed the cut-off value of the Day 1-5 E(2) to be 15.5 pg/mL, and an area under the curve (AUC) value of 0.674 for follicle growth and 0.752 for ovulation. The results suggest that cycles with a Day 1-5 E(2)≥15.5 pg/mL have a higher rate of follicle growth and ovulation in patients with POI.

Concerted functions of anions and cations in a molecular ionic crystal with stable three-dimensional micropores.

The molecular ionic crystal [Cr3O(OOCCH═CH2)6(H2O)3]3[α-PW12O40]·15H2O [Ia] with stable three-dimensional micropores and a minimum aperture of 3.3 Å was synthesized with a phosphododecatungstate [α-PW12O40](3-) (polyoxometalate, POM) and a macrocation with acrylate ligands [Cr3O(OOCCH═CH2)6(H2O)3](+). The porous structure of Ia was basically constructed by an arrangement of macrocations forming a six-membered ring: vinyl groups (CH═CH2) of adjacent macrocations were aligned parallel to each other, suggesting a weak dispersion force between them. A guest-free phase [Cr3O(OOCCH═CH2)6(H2O)3]3[α-PW12O40] [Ib] was formed by the treatment of Ia in vacuo at room temperature without any structure change. Compound Ib showed shape-selective sorption of CO2 and C2H2 (molecular size = 3.3 Å) over N2 (3.6 Å) and methane (3.7 Å), and the sorption enthalpy of C2H2 was larger than that of CO2. The high affinity toward C2H2 was further confirmed as follows: the Monte Carlo simulations of the optimized geometries of C2H2 in Ib showed that both hydrogen atoms were in the vicinity of the surface oxygen atoms of POMs. The gas sorption profiles showed a much faster diffusion for C2H2. All these results suggest that the anion and cation mainly play the guest-binding and structure-directing roles, respectively, (i.e., concerted functions) in an ionic crystal with stable three-dimensional micropores.