MOP X MOF: Collaborative Combination of Metal-Organic Polyhedra

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Functional Inorganic Materials and Devices

MOP X MOF: Collaborative Combination of Metal-Organic Polyhedra and Metal-Organic Framework for Proton Conductivity Jiyoung Lee, Dae-Woon Lim, Shun Dekura, Hiroshi Kitagawa, and Wonyoung Choe ACS Appl. Mater. Interfaces, Just Accepted Manuscript • DOI: 10.1021/acsami.9b01026 • Publication Date (Web): 06 Mar 2019 Downloaded from http://pubs.acs.org on March 7, 2019

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ACS Applied Materials & Interfaces

MOP X MOF: Collaborative Combination of MetalOrganic Polyhedra and Metal-Organic Framework for Proton Conductivity Jiyoung Lee,† Dae-Woon Lim,‡ Shun Dekura, ‡,§ Hiroshi Kitagawa,*,‡, and Wonyoung Choe*,† †Department ‡Division

of Chemistry, Ulsan National Institute of Science and Technology, Ulsan, Korea

of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-

Oiwakecho, Sakyo-ku, Kyoto 606-8502, Japan §

Institute for Solid State Physics, University of Tokyo; 5-1-5 Kashiwanoha, Kashiwa, Chiba

277-8581, Japan

Keywords: Metal-Organic Frameworks, Metal-Organic Polyhdra, Hybrid Materials, Proton Conductivity, Porous Materials

ACS Paragon Plus Environment

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Abstract. We report a hybrid solid systems, UMOM-100-a and UMOM-100-b, synthesized by incorporation of Cu-based metal-organic polyhedra (MOPs) into a porous metal-organic framework (MOF) host, PCN-777. The MOP guests have acid (SO3-) functional groups, acting as functionalized nanocages, while the porosity is still maintained for proton conductivity. The key parameter for UMOM-100 series is the amount of MOPs inside MOF, which controls the ratio between meso- and micropores, polarity, and finally proton conductivity. This is an example demonstrating a new design strategy for porous solids to add active components into porous metal-organic frameworks, opening up possibilities in other applications such as solid- state electrolytes, and heterogeneous catalysts.

Introduction Porous materials have received attention due to their potential in energy applications such as heterogeneous catalysis and gas storage/separation.1,2 Especially, metal-organic frameworks (MOFs), a new class of porous materials assembled from metal clusters and organic ligands, have attracted worldwide interests during the past two decades.3-5 These materials have been used by taking advantage of unique characteristics such as structural tunability and high surface area with ordered crystalline pores.5-7 To enhance the properties of MOFs, synthetic approach to add functionality into MOFs has continuously evolved. Specifically, there are three ways to incorporate functional sites into MOFs, as shown in Figure 1: (1) modifications of organic ligands via organic reactions8-12 (2) decorating metal clusters via coordination bonding13-16 (3) incorporation of functional guest species in the pores of MOF structures.17 Among these strategies, in particular, the last strategy is unique to provide broad range of functionality to


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MOFs because of the diversity of guest species (metal nanoparticle, polyoxometalate, dye, and biomolecules)17-24, a possibility of fine-tuning through the control of incorporation amounts, and applicability in a wide range of host material under the mild condition without structure deformation. Nevertheless, the limited pore aperture size can be a drawback in case of oversize guest molecules. Therefore, the appropriate host framework and guest molecule selection for application of interest is important. There are few hybrid MOFs for incorporation of metal-organic polyhedron (MOP) nanocages, discrete coordination complex assembled from metal ions and functionalized organic ligands,25-27 used in catalysis, molecular recognition, and biochemical applications.28-31 Yaghi group successfully demonstrated incorporation of 3.4 nm MOP-18 into IRMOF-74-IV.32 Recently, Li group reported new synthetic approach to encapsulate octahedral MOP cages into MIL-101 through hydrophilicity-directed approach.33 Despite of these efforts, there are rooms for improvement in new applications for MOP/MOF hybrid materials. Here, we introduce new functional MOP/MOF hybrid materials (UMOM-100-a and UMOM100-b, UMOM: UNIST metal-organic material) by incorporating acid functionalized Cu(II) based nanosized cuboctahedron MOP into a mesoporous MOF, PCN-777. We successfully demonstrate the encapsulation of MOP nanocage into PCN-777 through wet-impregnation approach by using the solubility of MOP in organic solvent. As a result, three types of physicochemical functionalities of PCN-777 were tuned depending on the contained MOP contents: (1) micro/mesoporosity was manipulated by inclusion amounts of MOPs, (2) polarity of pristine MOF was changed due to the induced functional group of MOPs and (3) evolution of proton conductivity found in UMOM-100-a and UMOM-100-b.


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Result and discussion PCN-777 (a robust mesoporous MOF)34 and MOP 3 (a Cu(II) paddlewheel-based cuboctahedron MOP)35 were selected as the host and guest, respectively. The pristine PCN-777 was prepared by the solvothermal reaction of ZrOCl2·8H2O with 4,4',4''-s-triazine-2,4,6-triyl-tribenzoic acid (TATB) in the presence of N, N'-diethylformamide (DEF) and trifluoroacetic acid.34 PCN-777 has a β-cristobalite-type structure and possesses two types of cages, 1.5 nm tetrahedral and 3.8 nm truncated tetrahedral cage.34 Especially, 3.8 nm cage makes PCN-777 as suitable host materials for incorporating other functional moieties (Figure 2a).34 MOP 3, Na6H18[Cu24(SO3–mBDC)24(G)24] where G represents a coordinated solvent to metal node, is one of the Cu(II) paddlewheel-based cuboctahedron MOPs composed of 12 Cu2(COO)4 paddlewheel nodes and 24 5-sulfoisophthalic acid (SO3–-mBDC) (Figure 2b).35 Due to the size and solubility of cuboctahedron cage, MOP 3 is a good guest candidate to be incorporated in mesoporous PCN777. In addition, the extra functional group of organic ligands of MOP 3 will provide new functionality into the MOP/MOF hybrid materials. UMOM-100-a and UMOM-100-b were obtained by using wet-impregnation approach which is suggested by Zhou group.28 MOP 3 solution was prepared by dissolving few milligrams of MOP 3 in methanol. The peak at 695 nm of UV-visible absorbance spectrum of MOP 3 solution represents that the existence of dicopper paddlewheel unit in MOP 3 solution (Figure S1 and S2).36 UMOM-100-a was obtained by mixing ~50 mg of PCN-777 and MOP 3 solution (91 mg of MOP 3 was dissolved in 30 mL of MeOH) for 2 hours. UV-visible absorbance spectrum of MOP 3 solution shows that the peak intensity decreases at 695 nm after incorporation procedure (Figure S1). It implies that most of the MOP 3 cages are well encapsulated within PCN-777. Furthermore, UMOM-100-b was obtained using a similar incorporating process of UMOM-100-


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a, except for concentration of MOP 3 solution and encapsulation time. UV-visible absorbance spectrum difference of MOP 3 solution was confirmed after incorporating reaction (Figure S2). After encapsulation reaction of MOP 3, the color of PCN-777 samples was changed white to blue. It clearly visualizes the incorporation of Cu(II) (Figure S3). Powder X-ray diffraction patterns of UMOM-100-a and UMOM-100-b were well matched with Powder X-ray diffraction patterns of as-synthesized PCN-777 (Figure 3a). It shows that the crystallinity of PCN-777 was well preserved after wet-impregnation process. The successfully encapsulation of MOP 3 in PCN-777 was confirmed by 1H-NMR and inductively coupled plasma optical emission spectrometry (ICP-OES) analysis using digested samples after several washing steps. 1H-NMR spectra of PCN-777, UMOM-100-a, and UMOM-100-b show the ratio between TATB and SO3–-mBDC in each case, which is 1.00:0.00, 1.00:0.33 and 1:0.47, respectively (Figure S4-S6). Based on the ratio, the number of MOP 3 cages in a unit cell of PCN-777 was calculated on the assumption that there are no defect linkers both PCN-777 and MOP 3. It represents that around 2.7 cages and 3.7 cages are encapsulated in a unit cell of PCN777 in case of UMOM-100-a and UMOM-100-b, respectively. The existence of copper in each sample was confirmed by ICP-OES analysis (Table S1). It shows that UMOM-100-b contains more copper amount than UMOM-100-a similar with 1H-NMR data. The existence of Cu(II) species was further characterized by obtaining diffuse reflectance UV-visible absorption spectrum of PCN-777 and UMOM-100-b (Figure S7). The absorbance peak of UMOM-100-b at around 800 nm represents the d-d transition of Cu (II).37,38 Fourier Transform Infrared (FT-IR) spectrum of UMOM-100-b also supports the encapsulation of MOP 3 within PCN-777 (Figure 3b). The peak at 1605 cm–1 represent asymmetric stretching mode of COO–-Cu(II) complex, vas(Cu-COO–). It well agrees with a previous report which


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mentioned that asymmetric stretching mode of bidentate bridged COO–-Cu(II) is usually characterized at 1600-1630 cm–1 region.39 A value of splitting (Δ) between vas(Cu-COO–) and vs(Cu-COO–) of UMOM-100-b is smaller than 200 cm–1. It indicates the existence of bridging bidentate Cu(II) coordination of COO–-Cu (II) complex.39 The peak at 1360 cm–1 and 1520 cm–1 represent symmetric stretching mode and asymmetric stretching mode of COO–-Zr(IV) complex, vs(Zr-COO–) and vas(Zr-COO–), respectively. A value of splitting (Δ) between vas(Zr-COO–) and vs(Zr-COO–) of UMOM-100-b is in range of 130-200 cm–1. It indicates the existence of bridging COO–-Zr(IV) complex.40 The symmetric stretching mode of SO3– is assigned in a peak at 1040 cm–1. Based on the analysis, we speculate that Cu(II) based MOP 3 cages are well encapsulated without decomposition. Scanning electron microscopy (SEM) images of PCN-777 and UMOM-100-b show that there is no morphology change after the encapsulation reaction (Figure S8-S9). Energy dispersive spectroscopy (EDS) elementary mapping images of UMOM-100-b clearly show that the homogeneous distribution of Cu and S which are components of MOP 3, although there is no signal of Cu and S in PCN-777 (Figure S8-S9). The permanent porosity of UMOM-100-a and UMOM-100-b were confirmed by N2 sorption experiment (Figure 4a). The total pore volume and Brunauer-Emmet-Teller surface area are gradually decreased when the number of incorporated MOP 3 cages are increased (Table S2). Pore size distribution of samples were calculated by using DFT slit model (Figure 4b). When the number of encapsulated MOP 3 cages are increased, the size of 3.4 nm of mesopore is gradually decreased with decreasing of pore volume. Interestingly, 1-2 nm of micropores are created when number of incorporated MOP 3 cages are increased. As shown in Table S2, the value of


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Vmicro/Vmeso (Vmicro represents microporous pore volume and Vmeso represents mesoporous pore volume) is gradually increased when the amount of encapsulated MOP 3 cages is increased. To estimate the location of a MOP 3 cage within PCN-777, we suggest two different models with 3.8 nm of a truncated tetrahedron cage of PCN-777 and a MOP 3 cage (Figure S10). Model A represents that a MOP cage exists on the hexagonal window of truncated tetrahedron cage of PCN-777 and model B represents that a MOP 3 cage exists in the center of truncated tetrahedron cage of PCN-777. To demonstrate which model is suitable for our system, pore size distribution of each model was simulated by using Poreblazer program (3.0.2 version). Pore size distribution of model A indicates two distinguished phenomena when MOP 3 contents are increased; 3.4 nm of mesopore size is gradually decreased with decreasing of pore volume, and gradual increase of micropores (Figure S11). However, pore size distribution of model B indicates following phenomena when MOP 3 contents are increased; 3.4nm of mesopore volume decreases without any mesopore size change, and new mesopore are generated. Meanwhile, there are gradual increase of microporosity (Figure S12). When we compare experimental pore size distribution data and simulated one, model A is more reasonable based on changes in micro/mesopores features. Figure 5 shows the differences of truncated tetrahedron cages of PCN-777 depending on MOP loading amount from 0 % to 100 % in a unit cell. Thermogravimetric analysis of UMOM-100-b represents that there is additional weigh loss at 280 oC due to the existence of MOP 3 (Figure S13). However, there is no thermal stability difference in PCN-777 with and without MOP 3 loading. To compare the polarity difference between PCN-777 and UMOM-100-b, powder samples of PCN-777 and UMOM-100-b were dispersed in ethanol (EtOH, dielectric constant: 24.341) and


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dichloromethane (DCM, dielectric constant: 9.0841) (Figure S14). PCN-777 showed good dispersion in both solvents but UMOM-100-b was well dispersed only in EtOH. UMOM-100-b was aggregated when the sample was dispersed in DCM. It represents that hydrophilic property with the polarity change was modified after encapsulating of acid-functionalized MOP 3. The polarity change was clearly reflected in water vapor adsorption and desorption isotherms measured at 298 K. Although UMOM-100 samples exhibited a lower porosity and surface area than pure PCN-777 in N2 adsorption, their water vapor adsorption capacities are approximately 1.5 times higher than that of pure PCN-777, which is attributed to the enhanced hydrophilicity by sulfonic acid group on the surface of MOP as shown in powder dispersion in EtOH. However, the difference of including MOP amounts is not so effective in water vapor uptake amounts (Figure 6a). In general, MOFs containing non-volatile acid molecules in pore or acid functional group in the organic ligand play a good proton conductor under the humidified condition due to the efficient proton donation and hydrogen bonding networks formation between water molecules and acid species.42-46 To verify the potential application of acid functionalized PCN-777 as a proton conductor, through the incorporation of acid functionalized MOP 3 cages, the alternating-current (A.C) impedance was measured by using a compacted pellet of powder samples. For evolution of proton conductivity, all Nyquist plots were obtained under the different relative humidity (RH %) at various temperatures (Figure 6b and Figure S15-S16). At low humidity condition, the conductivities of UMOM-100-a and UMOM-100-b under the RH 30% at 298 K were 8.73×10–11 and 8.03×10–11 S cm–1, respectively. Consequently, the values of conductivity are incredibly increased up to seven orders of magnitude (1.40×10–4 S cm–1 for UMOM-100-a and 2.11×10–4 S cm–1 for UMOM-100-b) as temperature and humidity increased up to the 90 % RH at 80 oC,


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which is comparable to acid functionalized MIL-53(Fe)-(COOH)2.47 It implied that the adsorbed water aids to diffuse the proton. On the contrary, the pure PCN-777 exhibited only four orders of magnitude increase (5.69×10–8 S cm-1) under 90 % RH at 80 oC (Table 1). As anticipated, the proton conductivity is strongly affected by acid-source, and the order of conductivity value is in good agreement with the amounts of MOP contents and H2O vapor sorption. The activation energy barrier for three compounds was estimated by Arrhenius plots (Figure 6c). The increased MOP amounts decrease activation energy from 0.87 to 0.66 eV with effective proton diffusion. The high activation energy barriers (> 0.4 eV) of three compounds estimated by least-squares fits in Figure 6c propose the Vehicle proton conduction mechanism because the reported activation energies for the Grotthuss and Vehicle mechanisms are in the region ca. 0.1–0.4 eV and ca. 0.5– 0.9 eV, respectively.44,49 The high activation barrier is attributed to the irregular MOP cage location, where protonic species are favored to diffuse proton with incomplete hydrogen bonding. In addition, the cycling experiment for UMOM-100-b clearly supports a reversible proton conductivity (Figure 6d). In particular, the hysteresis in water vapor sorption results in a higher proton conductivity at the second cycle of 30 % RH. Apparently, the water molecules facilitate proton conduction with increasing the proton concentration dissociated from the sulfonic acid group, which consequently enhance the mobile protons. The dynamic property of mobile proton was simply observed by temperature dependent solid-state 1H-NMR with line width analysis because 1H-NMR is a selectively sensitive probe for local molecular dynamics.50 As the temperature is lower than 298 K, the peak broadening is observed, implying the decreased mobility. Furthermore, once the temperature decreased below 183 K, the peak line width is not expanded anymore, suggesting an absence of mobile water species (Figure S17). As the temperature decreased below 298 K, the conductivity steeply dropped and indicated a detection


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limit at lower temperature than 263 K. This behavior strongly supports that ionic conductivity is originated from mobile proton.

Conclusion In conclusion, we demonstrated new MOP/MOF hybrid materials, UMOM-100-a and UMOM100-b, by controlling the loading amount of MOP 3. We suggested that 2.9 nm of MOP 3 cages were incorporated on the hexagonal window of truncated tetrahedron cage of PCN-777 based on the

simulation

data

of

pore

size

distribution.

Interestingly,

the

manipulation

of

micro/mesoporosity would be possible by modifying the incorporation amount of MOP 3 into PCN-777. In addition, polarity difference was demonstrated by dispersion the UMOM-100 series into different solvents. Furthermore, we demonstrated, for the first time, the proton conductive MOF/MOP hybrid material. The acid-functional group in MOP not only enhances water vapor uptake amounts but induces high proton conductivity. The cooperative proton conduction through the encapsulation of MOP and water molecule in the pore of MOF can provide an intuitive design strategy for new solid-state electrolyte.

Experimental section Materials. 4,4',4''-s-triazine-2,4,6-triyl-tribenzoic acid (TATB) (Sigma-Aldrich), monosodium 5sulfoiso phthalate (Na+SO3–-mBDC) (TCI), ZrOCl2·8H2O (Sigma-Aldrich) and Cu(OAc)2·H2O (JUNSEI) were used without further purification. N,N'-diethylformamide (DEF) and trifluoroacetic acid were obtained from TCI. N,N'-dimethylformamide (DMF), N,N'dimethylacetamide (DMA), Methyl alcohol (MeOH), acetone and nitric acid were obtained from JUNSEI.


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Instrumentation. UV-visible absorbance spectrum was obtained from Jasco V-670 spectrometer. Powder X-ray diffraction data was obtained from Bruker D2 phaser. 1H-Nuclear magnetic resonance (NMR) was performed on Bruker Avance III HD. Inductively coupled plasma (ICP) analysis was performed on Varian 700-ES. Diffuse reflectance UV-vis absorption spectrum was obtained from Agilent Cary 5000. Fourier-Transform Infrared (FT-IR) was performed on Thermo Scientific Nicolet iS10. Gas sorption isotherm was performed on Micromeritics ASAP 2020 instrument. Pore size distributions were obtained using DFT slit model with a N2 isotherm. Thermogravimetric Analyzer (TGA) was performed on a TA instrument SDT Q600, heated to 800 °C under N2 atmosphere at a scan rate of 5 °C min–1.

H2O vapor sorption measurement. The water vapor adsorption–desorption measurement was carried out on UMOM-100-a/-b using an automated micropore gas analyzer BELSORP-max (MicrotracBEL Corp.). Before the sorption measurement, all samples were activated at 100 °C under vacuum (10−3 Pa) for 5h. The H2O vapor isotherms were measured at each equilibrium pressure by the static volumetric method at 298 K under P/P0 = 0.95. Proton conductivity by impedance measurement. The alternating current (AC) conductivity measurements of the compounds were carried out by a conventional two-probe method. All samples were compacted as pellets of ~1.0 mm in thickness and 2.5 mm in diameter. They were tested using gold paste and gold wires (50 μm in diameter) and then put into a temperature and humidity control chamber, which was connected to a Solartron SI 1260 Impedance/Gain-Phase Analyzer and 1296 Dielectric Interface. The frequency range from 1 Hz to 1 MHz was used in various temperature with applied voltage of 100 mV. The proton conductivity (σ, S cm−1) and activation energy (Ea, eV) barrier were calculated by Eqs. (1) and (2), in which, L, S, and Z are


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the sample thickness (cm), electrode area (cm2) and impedance, respectively. A and k mean a pre-exponential factor and the Boltzmann constant.

σ=

𝐿

(1)

𝑍ｘ𝑆

σ𝑇 = Aexp(

-𝐸𝑎 𝑘𝑇

)

(2)

Solid-state 1H NMR measurement. Solid-state 1H NMR spectroscopy was performed using a Bruker Biospin K.K., ADVANCE II+ 400 NMR spectrometer at a frequency of 400 MHz equipped with a 5 mm SOL 1H K2423 probe. Solid sample of UMOM-100-b was equilibrated at 298 K and 95 % RH for 6 days in a humidity chamber, loaded into an NMR tube, and sequentially sealed prior to measurement. Synthesis of PCN-777. PCN-777 was obtained according to the reported synthetic method.34 A DEF (3.0 mL) solution of TATB (45 mg, mmol) was mixed with a DEF (3.0 mL) solution of ZrOCl2·8H2O (180 mg, mmol) in a 16 mL Teflon vial. After mixing, mixture was heated in 120 oC

for 12 h. After the reaction, ~50 mg of white powder was collected and washed with DMF

and acetone. Synthesis of MOP 3. MOP 3 was obtained by modifying the reported synthetic method.35 A MeOH (2.0 mL) solution of Na+SO3–-mBDC (67.3 mg, 0.25 mmol) was mixed with a MeOH/DMA (3.75 mL, v/v=1:1) solution of Cu(OAc)2·H2O (50.0 mg, 0.25 mmol) in a capped vial (10 mL). After mixing for 20 min, 1.25 mL of DMA and 10 μL of nitric acid was added to this solution and then allowed the vial open and stand at room temperature. After 5 days, synthesized crystals were collected and washed with DMA.


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Synthesis of UMOM-100-a. ~50mg of PCN-777 was washed with MeOH before encapsulation reaction. 91 mg of MOP 3 was dissolved in 30 mL of MeOH, followed by the addition of 50 mg of PCN-777. After mixing 2 h under nutator, the blue powder was collected by centrifuge. Synthesis of UMOM-100-b. ~50mg of PCN-777 was washed with MeOH before encapsulation reaction. 188 mg of MOP 3 was dissolved in 30 mL of MeOH, followed by the addition of 50 mg of PCN-777. After mixing 26 h under nutator, the blue powder was collected by centrifuge. ASSOCIATED CONTENT Supporting Information. UV-visible absorbance, 1H-NMR spectrum of PCN-777, UMOM100-a and UMOM-100-b, ICP-OES data of UMOM-100 series, Diffuse reflectance UV-visible absorbance spectrum of PCN-777 and UMOM-100-b, Surface area and pore volume of the samples, pore size distribution data, Nyquist plots of PCN-777, UMOM-100-a and UMOM-100b, Various temperature solid–state 1H NMR spectra are available. AUTHOR INFORMATION Corresponding Author * E-mail: [email protected] and [email protected] ORCID Wonyoung choe: 0000-0003-0957-1187 Hiroshi Kitagawa: 0000-0001-6955-3015 Notes The authors declare no competing financial interest.


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ACKNOWLEDGMENT This work was supported by Korea Environment Industry & Technology Institute (KEITI) through Public Technology Program based on Environmental Policy Program, funded by Korea Ministry of Environment (MOE) (2018000210002) and National Research Foundation of Korea (NRF-2016R1A5A1009405).

References (1) Davis, M. E., Ordered Porous Materials for Emerging Applications. Nature 2002, 417, 813821. (2) Slater, A. G.; Cooper, A. I., Function-led Design of New Porous Materials. Science 2015, 348, 988. (3) Long, J. R.; Yaghi, O. M., The Pervasive Chemistry of Metal-Organic Frameworks. Chem. Soc. Rev. 2009, 38, 1213-1214. (4) Zhou, H.-C.; Long, J. R.; Yaghi, O. M., Introduction to Metal-Organic Frameworks. Chem. Rev. 2012, 112, 673-674. (5) Furukawa, H.; Cordova, K. E.; O’Keeffe, M.; Yaghi, O. M., The Chemistry and Applications of Metal-Organic Frameworks. Science 2013, 341, 1230444. (6) Kuppler, R. J.; Timmons, D. J.; Fang, Q.-R.; Li, J.-R.; Makal, T. A.; Young, M. D.; Yuan, D.; Zhao, D.; Zhuang, W.; Zhou, H.-C., Potential Applications of Metal-Organic Frameworks. Coord. Chem. Rev. 2009, 253, 3042-3066. (7) Lu, W.; Wei, Z.; Gu, Z.-Y.; Liu, T.-F.; Park, J.; Park, J.; Tian, J.; Zhang, M.; Zhang, Q.; Gentle Iii, T.; Bosch, M.; Zhou, H.-C., Tuning the Structure and Function of Metal-Organic Frameworks via Linker Design. Chem. Soc. Rev. 2014, 43, 5561-5593.


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Page 15 of 28 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(8) Cohen, S. M., Postsynthetic Methods for the Functionalization of Metal–Organic Frameworks. Chem. Rev. 2012, 112, 970-1000. (9) Tanabe, K. K.; Cohen, S. M., Postsynthetic Modification of Metal-Organic Frameworks-A Progress Report. Chem. Soc. Rev. 2011, 40, 498-519. (10) Phang, W. J.; Jo, H.; Lee, W. R.; Song, J. H.; Yoo, K.; Kim, B.; Hong, C. S., Superprotonic Conductivity of a UiO-66 Framework Functionalized with Sulfonic Acid Groups by Facile Postsynthetic Oxidation. Angew. Chem. Int. Ed. 2015, 54, 5142-5146. (11) Canivet, J.; Aguado, S.; Schuurman, Y.; Farrusseng, D., MOF-Supported Selective Ethylene Dimerization Single-Site Cata-lysts through One-Pot Postsynthetic Modification. J. Am. Chem. Soc. 2013, 135, 4195-4198. (12) Luan, Y.; Zheng, N.; Qi, Y.; Yu, J.; Wang, G., Development of a SO3H-Functionalized UiO-66 Metal–Organic Framework by Postsynthetic Modification and Studies of Its Catalytic Activities. Eur. J. Inorg. Chem. 2014, 4268-4272. (13) Islamoglu, T.; Goswami, S.; Li, Z.; Howarth, A. J.; Farha, O. K.; Hupp, J. T., Postsynthetic Tuning of Metal–Organic Frameworks for Targeted Applications. Acc. Chem. Res. 2017, 50, 805-813. (14) Hwang, Y.; Hong, D.; Chang, J.; Jhung, S.; Seo, Y.; Kim, J.; Vimont, A.; Daturi, M.; Serre, C.; Férey, G., Amine Grafting on Coordinatively Unsaturated Metal Centers of MOFs: Consequences for Catalysis and Metal Encapsulation. Angew. Chem. Int. Ed. 2008, 47, 41444148. (15) Deria, P.; Mondloch, J. E.; Tylianakis, E.; Ghosh, P.; Bury, W.; Snurr, R. Q.; Hupp, J. T.; Farha, O. K., Perfluoroalkane Functionalization of NU-1000 via Solvent-Assisted Ligand Incorporation: Synthesis and CO2 Adsorption Studies. J. Am. Chem. Soc. 2013, 135, 16801-


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16804. (16) Chen, C.; Wu, Z.; Que, Y.; Li, B.; Guo, Q.; Li, Z.; Wang, L.; Wan, H.; Guan, G., Immobilization of A Thiol-Functionalized Ionic Liquid onto HKUST-1 through Thiol Compounds as the Chemical Bridge. RSC Adv. 2016, 6, 54119-54128. (17) Evans, J. D.; Sumby, C. J.; Doonan, C. J., Post-Synthetic Metalation of Metal-Organic Frameworks. Chem. Soc. Rev. 2014, 43, 5933-5951. (18) Fang, Y., Li, J., Togo, T., Jin, F., Xiao, Z., Liu, L., Drake, H., Lian, X., and Zhou, H.-C., Ultra-Small Face-Centered-Cubic Ru Nanoparticles Confined within A Porous Coordination Cage for Dehydrogenation. Chem, 2018, 4, 555-563. (19) Cui, Y.; Li, B.; He, H.; Zhou, W.; Chen, B.; Qian, G., Metal–Organic Frameworks as Platforms for Functional Materials. Acc. Chem. Res. 2016, 49, 483-493. (20) Jiang, H.-L.; Xu, Q., Porous Metal-Organic Frameworks as Platforms for Functional Applications. Chem. Commun. 2011, 47, 3351-3370. (21) Férey, G.; Mellot-Draznieks, C.; Serre, C.; Millange, F.; Dutour, J.; Surblé, S.; Margiolaki, I., A Chromium Terephthalate-Based Solid with Unusually Large Pore Volumes and Surface Area. Science 2005, 309, 2040-2042. (22) Yu, J.; Cui, Y.; Xu, H.; Yang, Y.; Wang, Z.; Chen, B.; Qian, G., Confinement of Pyridinium Hemicyanine Dye within an Anionic Metal-Organic Framework for Two-Photon-Pumped Lasing. Nat. Commun. 2013, 4, 2719. (23) Lykourinou, V.; Chen, Y.; Wang, X.-S.; Meng, L.; Hoang, T.; Ming, L.-J.; Musselman, R. L.; Ma, S., Immobilization of MP-11 into a Mesoporous Metal–Organic Framework, MP11@mesoMOF: A New Platform for Enzymatic Catalysis. J. Am. Chem. Soc. 2011, 133, 1038210385.


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Page 17 of 28 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(24) Hu, P.; Morabito, J. V.; Tsung, C.-K., Core–Shell Catalysts of Metal Nanoparticle Core and Metal–Organic Framework Shell. ACS Catal. 2014, 4, 4409-4419. (25) Tranchemontagne, D. J.; Ni, Z.; O'Keeffe, M.; Yaghi, O. M., Reticular Chemistry of Metal– Organic Polyhedra. Angew. Chem. Int. Ed. 2008, 47, 5136-5147. (26) Ahmad, N.; Chughtai, A. H.; Younus, H. A.; Verpoort, F., Discrete Metal-Carboxylate SelfAssembled Cages: Design, Synthesis and Applications. Coord. Chem. Rev. 2014, 280, 1-27. (27) Perry IV, J. J.; Perman, J. A.; Zaworotko, M. J., Design and Synthesis of Metal–Organic Frameworks using Metal–Organic Polyhedra as Supermolecular Building Blocks. Chem. Soc. Rev. 2009, 38, 1400-1417. (28) Sun, L.-B.; Li, J.-R.; Lu, W.; Gu, Z.-Y.; Luo, Z.; Zhou, H.-C., Confinement of Metal– Organic Polyhedra in Silica Nanopores. J. Am. Chem. Soc. 2012, 134, 15923-15928. (29) Kang, Y.-H.; Liu, X.-D.; Yan, N.; Jiang, Y.; Liu, X.-Q.; Sun, L.-B.; Li, J.-R., Fabrication of Isolated Metal–Organic Polyhedra in Confined Cavities: Adsorbents/Catalysts with Unusual Dispersity and Activity. J. Am. Chem. Soc. 2016, 138, 6099-6102. (30) Kumar, R.; Rao, C. N. R., Novel Properties of 0D Metal-Organic Polyhedra Bonded to the Surfaces of 2D Graphene and 1D Single-Walled Carbon Nanotubes. Dalton Trans. 2017, 46, 7998-8003. (31) Ahmad, N.; Younus, H. A.; Chughtai, A. H.; Verpoort, F., Metal–Organic Molecular Cages: Applications of Biochemical Implications. Chem. Soc. Rev. 2015, 44, 9-25. (32) Deng, H.; Grunder, S.; Cordova, K. E.; Valente, C.; Furuka-wa, H.; Hmadeh, M.; Gándara, F.; Whalley, A. C.; Liu, Z.; Asahina, S.; Kazumori, H.; O’Keeffe, M.; Terasaki, O.; Stoddart, J. F.; Yaghi, O. M., Large-Pore Apertures in a Series of Metal-Organic Frameworks. Science 2012, 336, 1018-1023.


17


Page 18 of 28

(33) Qiu, X.; Zhong, W.; Bai, C.; Li, Y., Encapsulation of a Metal–Organic Polyhedral in the Pores of a Metal–Organic Framework. J. Am. Chem. Soc. 2016, 138, 1138-1141. (34) Feng, D.; Wang, K.; Su, J.; Liu, T.-F.; Park, J.; Wei, Z.; Bosch, M.; Yakovenko, A.; Zou, X.; Zhou, H.-C., A Highly Stable Zeotype Mesoporous Zirconium Metal–Organic Framework with Ultralarge Pores. Angew. Chem. Int. Ed. 2015, 54, 149-154. (35) Li, J.-R.; Zhou, H.-C., Bridging-Ligand-Substitution Strategy for the Preparation of Metal– Organic Polyhedra. Nat. Chem. 2010, 2, 893-898. (36) Li, Y.; Zhang, D.; Gai, F.; Zhu, X.; Guo, Y.-N.; Ma, T.; Liu, Y.; Huo, Q., Ionic SelfAssembly of Surface Functionalized Metal-Organic Polyhedra Nanocages and Their Ordered Honeycomb Architecture at the Air/Water Interface. Chem. Commun. 2012, 48, 7946-7948. (37) Prestipino, C.; Regli, L.; Vitillo, J. G.; Bonino, F.; Damin, A.; Lamberti, C.; Zecchina, A.; Solari, P. L.; Kongshaug, K. O.; Bordiga, S., Local Structure of Framework Cu(II) in HKUST-1 Metallorganic Framework: Spectroscopic Characterization upon Activation and Interaction with Adsorbates. Chem. Mater. 2006, 18, 1337-1346. (38) Kim, H. K.; Yun, W. S.; Kim, M.-B.; Kim, J. Y.; Bae, Y.-S.; Lee, J.; Jeong, N. C., A Chemical Route to Activation of Open Metal Sites in the Copper-Based Metal–Organic Framework Materials HKUST-1 and Cu-MOF-2. J. Am. Chem. Soc. 2015, 137, 10009-10015. (39) Tan, K.; Nijem, N.; Canepa, P.; Gong, Q.; Li, J.; Thonhauser, T.; Chabal, Y. J., Stability and Hydrolyzation of Metal Organic Frameworks with Paddle-Wheel SBUs upon Hydration. Chem. Mater. 2012, 24, 3153-3167. (40) Lausund, K. B.; Nilsen, O., All-Gas-Phase Synthesis of UiO-66 through Modulated Atomic Layer Deposition. Nat. Commun. 2016, 7, 13578. (41) Maryott, A. A.; Smith, E. R.; Table of dielectric constants of pure liquids, National Bureau


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Page 19 of 28 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Of Standards, Gaithersburg MD, 1951. (42) Ponomareva, V. G.; Kovalenko, K. A.; Chupakhin, A. P.; Dybtsev, D. N.; Shutova, E. S.; Fedin, V. P., Imparting High Proton Conductivity to a Metal–Organic Framework Material by Controlled Acid Impregnation. J. Am. Chem. Soc. 2012, 134, 15640-15643. (43) Taylor, J. M.; Dawson, K. W.; Shimizu, G. K. H., A Water-Stable Metal–Organic Framework with Highly Acidic Pores for Proton-Conducting Applications. J. Am. Chem. Soc. 2013, 135, 1193-1196. (44) Dong, X.-Y.; Li, J.-J.; Han, Z.; Duan, P.-G.; Li, L.-K.; Zang, S.-Q., Tuning the Functional Substituent Group and Guest of Metal–Organic Frameworks in Hybrid Membranes for Improved Interface Compatibility and Proton Conduction. J. Mater. Chem. A 2017, 5, 3464-3474. (45) Zhang, F.-M.; Dong, L.-Z.; Qin, J.-S.; Guan, W.; Liu, J.; Li, S.-L.; Lu, M.; Lan,Y.-Q.; Su, Z.-M.; Zhou, H.-C., Effect of Imidazole Arrangements on Proton-Conductivity in Metal–Organic Frameworks. J. Am. Chem. Soc. 2017, 139, 6183-6189. (46) Pili, S.; Rought, P.; Kolokolov, D. I.; Lin, L.; Silva, I. d.; Cheng, Y.; Marsh, C.; Silverwood, I. P.; Sakai, V. G.; Li, M.; Titman, J. J.; Knight, L.; Daemen, L. L.; Ramirez-Cuesta, A. J.; Tang, C. C.; Stepanov, A. G.; Yang, S.; Schröder, M., Enhancement of Proton Conductivity in Nonporous Metal–Organic Frameworks: The Role of Framework Proton Density and Humidity. Chem. Mater. 2018, 30, 7593-7602. (47) Shigematsu, A.; Yamada, T.; Kitagawa, H., Wide Control of Proton Conductivity in Porous Coordination Polymers. J. Am. Chem. Soc. 2011, 133, 2034-2036. (48) Agmon, N., The Grotthuss mechanism. Chem. Phys. Lett. 1995, 244, 456-462. (49) Kreuer, K.-D.; Rabenau, A.; Weppner, W., Vehicle Mecha-nism, A New Model for the Interpretation of the Conductivity of Fast Proton Conductors. Angew. Chem. Int. Ed. 1982, 21,


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208-209. (50) Schmidt-Rohr K.; Spiess, H. W., Multidimensional Solid-State NMR and Polymers; Academic Press, San Diego, 1994.


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Figure 1. The schematic representation of various strategies for incorporation of functional moieties; Modifications of organic ligands via organic reactions (left), decorating metal clusters via coordination bonding (middle), and incorporation of functional guest species in the pores of MOF structures (right).


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a

+ 6-connected Zr6

TATB

b

+ Cu(II) paddlewheel

SO3¯-mBDC

Figure 2. Schematic illustration of (a) construction of truncated tetrahedral mesoporous cages of PCN-777 from Zr6 cluster and TATB and (b) construction of cuboctahedron MOP 3 from Cu(II) paddlewheel and SO3--mBDC. Zr, Blue; Cu, green; N, sky blue; C, grey; O, red; S, yellow; all hydrogen and solvents on the Cu2(COO)4 paddlewheels are omitted for clarity.


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a

b

Figure 3. (a) Powder X-ray diffraction patterns of pristine PCN-777, UMOM-100-a and UMOM-100-b. (b) FT-IR spectrum of PCN-777, UMOM-100-b and MOP 3.


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a

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b

Figure 4. (a) N2 sorption isotherm of PCN-777, UMOM-100-a and UMOM-100-b at 77 K after activating at 100 °C for 5 h. (b) Pore size distribution of PCN-777, UMOM-100-a and UMOM100-b measured by the N2 sorption isotherm at 77 K.


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a

b

+ c

0%

25%

50%

75%

100%

Figure 5. (a) Scheme of a truncated tetrahedron cage of PCN-777 and a MOP 3 cage. (b) Scheme of incorporation of a MOP 3 on the hexagonal window of a truncated tetrahedron cage of PCN-777 (c) Schematic illustration of truncated tetrahedron cages of PCN-777 depending on MOP loading amount from 0% to 100% in a unit cell.


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a

b

c

d

Page 26 of 28

Figure 6. Water vapor sorption and proton conductivity measurements. (a) Water sorption isotherms of PCN-777, UMOM-100-a and UMOM-100-b at 298 K after activating at 100 °C for 6 h. (b) Proton conductivity of PCN-777, UMOM-100-a and UMOM-100-b under the different relative humidity (RH) at 298K. (c) Arrhenius plots for activation energy barrier of PCN-777, UMOM-100-a and UMOM-100-b. Least-squares fitting is shown as solid lines. The calculated activation barrier is 0.87 eV (PCN-777), 0.78 eV (UMOM-100-a), and 0.66 eV (UMOM-100-b). (d) Cycling test of UMOM-100-b between 30% and 95% RH at 298K.


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Table 1. Comparison of proton conductivity and activation energy

Conductivity (S cm-1) Compounds

Ea (eV) RT/RH 30 %

RT/RH 95 %

80 oC/RH 90 %

PCN-777

1.10x10-12

3.59x10-10

5.69x10-8

0.87

UMOM-100-a

8.73x10-11

1.56x10-6

1.40x10-4

0.78

UMOM-100-b

8.03x10-11

6.47x10-6

2.11x10-4

0.66


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Table of Contents artwork


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MOP X MOF: Collaborative Combination of Metal-Organic Polyhedra

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