A Flexible Doubly Interpenetrated Metal–Organic Framework with

Article pubs.acs.org/IC

A Flexible Doubly Interpenetrated Metal−Organic Framework with Breathing Behavior and Tunable Gate Opening Effect by Introducing Co2+ into Zn4O Clusters Xiaodong Sun, Shuo Yao, Guanghua Li, Lirong Zhang,* Qisheng Huo, and Yunling Liu* State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130012, People’s Republic of China S Supporting Information *

ABSTRACT: A Zn4O clusters based flexible doubly interpenetrated metal−organic framework [(Zn4O)2(DCPB)6DMF]·2DMF·8H2O (JLU-Liu33, H2DCPB = 1,3-di(4carboxyphenyl)benzene, DMF = N,N-dimethylformamide) with pcu topology has been solvothermally synthesized. Because of its flexible structure, JLU-Liu33 exhibits a breathing behavior upon N2 and CO2 adsorption at low temperature, and C2H6 and C3H8 adsorption at 273 and 298 K. Furthermore, by adopting the direct synthesis method, two isomorphic compoundsJLU-Liu33L and JLU-Liu33H have been obtained by partial substituting Zn with different amounts of Co into the JLU-Liu33 framework. The gas adsorption study of Co-doped materials reveals that the gate opening effect of JLU-Liu33 can be modulated by introducing different contents of Co2+ into Zn4O clusters. Meanwhile, with the increasing amount of Co2+, the adsorption amount and isosteric enthalpy values for CO2 have been improved. It is worth mentioning that JLU-Liu33H exhibits commendable selectivity for CO2 over CH4 which may be a good candidate for industrial gas purification and air separation applications.

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INTRODUCTION Metal−organic frameworks (MOFs) have aroused extensive interests, bceause of their intriguing topological structure and potential applications in industry, such as gas adsorption and separation, chemical sensing, luminescence, and catalysis.1−8 In previous research, many extended ligands were designed and synthesized to construct MOFs with large pore size and high surface area.9−11 However, the excessive empty space generated from extended ligands easily lead to the collapse of the framework. Interpenetration, which is referenced as catenation, can minimize the empty space and significantly enhance the stability of frameworks.12−16 Although the interpenetrated motifs reduce the porosity, the interpenetrated MOFs materials still possess many unique properties, such as stepwise gas adsorption, guest-responsive porosity, and photoluminescence control.17−23 Of these aspects, the characteristic of stepwise adsorption is attractive and deserves further exploration. The flexible interpenetrated materials with stepwise adsorption can be also vividly described as breathing MOFs.24−26 Breathing MOFs cannot adsorb gas in their closed state, but the gas can pass through the gate at high pressure or low temperature. It can be ascribed that the flexible interpenetrated frameworks are linked by weak interactions (π−π stacking, hydrogen bonds, or van der Waals interaction) and the framework can modulate their interframework distance when they are exposed to external stimulation.27−29 In addition, the breathing behaviors © 2017 American Chemical Society

also rely on the strength of the intermolecular interactions which make different adsorbates have exclusive gate opening pressure.30 Inspired by the above, researchers are committed to investigating flexible interpenetrated MOFs with the potential of gas storage and purification.31−33 One of the most fascinating breathing MOFs is MIL-53, which showed specific breathing behavior upon CO 2 adsorption.34−36 Another excellent flexible interpenetrated MOF has been reported by Martin Schröder’s group, which could achieve the goals of gas adsorption and separation by modulating the degree of interpenetration.20 However, works are seldom focused on the metal substitution, exchange, or transmetalation of MOFs to modulate the gate opening pressure.37−40 This is because doping different metal ions into the porous framework are restricted by the following. First, it is difficult to obtain the network with desired identical structure by direct synthesis method. Second, although the different metals could be substituted into the metal clusters via post-synthesis modification (PSM), it has a tendency to lose the crystallinity and change their network in the process of isomorphic substitution.41−44 Herein, a flexible doubly interpenetrated MOF (JLU-Liu33), based on a V-shaped ligand and Zn4O clusters, was synthesized under solvothermal conditions. Received: March 21, 2017 Published: May 19, 2017 6645

DOI: 10.1021/acs.inorgchem.7b00744 Inorg. Chem. 2017, 56, 6645−6651

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hydrogen atoms were refined anisotropically. The final formula was derived from crystallographic data, combined with elemental and thermogravimetric analysis data. Crystallographic data collection and refinement parameters for JLU-Liu33 are listed in Table 1, and deposited with the Cambridge Crystallographic Data Center (CCDC) (No. 1517774).

Furthermore, we have successfully synthesized two isomorphic compounds JLU-Liu33L with low Co content and JLULiu33H with high Co content via a direct synthesis method (see Scheme 1). Scheme 1. Schematic of Introducing Co2+ into the Zn4O Cluster of JLU-Liu33

Table 1. Crystal Data and Structure Refinement for JLU-Liu 33a

Meanwhile, the gas adsorption studies indicate that the gate opening effect of JLU-Liu33 can be modulated by introducing Co ions into the framework. With the increasing of Co ions in the framework, the adsorption amount and isosteric enthalpy values for CO2 have been improved. In addition, JLU-Liu33H also exhibits commendable selectivity for CO2 over CH4.

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EXPERIMENTAL SECTION

Materials and Methods. All the materials were of reagent grade and used without further purification. Powder X-ray diffraction (PXRD) data were collected on a Rigaku D/max-2550 diffractometer with Cu Kα radiation (λ = 1.5418 Å) over the 2θ range of 3°−40° at room temperature. Elemental analyses (C, H, and N) were achieved by using a Vario MICRO system (Elementar, Germany). Thermogravimetric (TG) analyses were performed on TGA Q500 thermogravimetric analyzer in air with a heating rate of 10 °C min−1. Infrared spectra were recorded on a Bruker IFS-66v/S FTIR spectrometer in the range of 400−4000 cm−1, using the KBr pellet. Inductively coupled plasma (ICP) analyses were carried out on a PerkinElmer Optima 3300Dv spectrometer. Synthesis of JLU-Liu33. A mixture of H2DCPB (6 mg, 0.02 mmol), Zn(NO3)2·6H2O (9 mg, 0.03 mmol), DMF (1 mL), and triethylamine (0.025 mL) were kept at 85 °C for 12 h, followed by cooling to room temperature. Colorless octahedron crystals were obtained and then washed with fresh DMF and air-dried (yield 80%). Elemental analysis (%) for the JLU-Liu33: Calcd C, 55.36; H, 3.77; N, 1.47; Found C, 55.07; H, 3.88; N, 1.49. The purity of the bulk sample was confirmed by PXRD (see Figure S1 in the Supporting Information). Synthesis of JLU-Liu33L and JLU-Liu33H. JLU-Liu33L and JLU-Liu33H were prepared under the same procedure with different cobalt contents by using Co(NO3)2·6H2O: 3 mg (0.01 mmol) Co(NO3)2·6H2O mixed with 6 mg (0.02 mmol) Zn(NO3)2·6H2O for JLU-Liu33L; 6 mg (0.02 mmol) Co(NO3)2·6H2O mixed with 3 mg (0.01 mmol) Zn(NO3)2·6H2O for JLU-Liu33H. Through postsynthesis modification (PSM), Co2+ can also be introduced into the framework of JLU-Liu33. However, compared with a direct synthesis method, the crystals have a tendency to lose crystallinity during the PSM, which can be confirmed from the PXRD patterns of the materials (JLU-Liu33, JLU-Liu33L, JLU-Liu33H, and the sample after PSM). Meanwhile, through the direct synthesis method, more Co2+ could be introduced into the framework of JLU-Liu33, compared with the method of PSM, which can be confirmed from the ICP data (see Figure S2 and Table S3 in the Supporting Information). X-ray Crystallography. Crystallographic data for JLU-Liu33 were collected on a Bruker Apex II CCD diffractometer, using graphitemonochromated Mo Kα (λ = 0.71073 Å) radiation at 293(2) K. The structure was solved by a direct method and refined on F2 by fullmatrix least-squares, using the SHELXTL-97 program.45 All the metal atoms were located first, and then the oxygen and carbon atoms of the compound were subsequently found in difference Fourier maps. The hydrogen atoms of the ligand were placed geometrically. All non-

parameter

value/remark

compound formula formula weight temperature (K) wavelength (Å) crystal system, space group a (Å) b (Å) c (Å) V (Å3) Z Dc (Mg/m3) F(000) θ range reflns collected/unique Rint data/restraints/parameters GOF on F2 R1, wR2 (I > 2σ(I)) R1, wR2 (all data)

JLU-Liu 33 C129H109N3O37Zn8 2816.15 296(2) K 0.71073 Å trigonal, R3c 23.3701(5) 23.3701(5) 78.597(2) 37175.4(16) 6 0.755 8640 1.13°−25.13° 76722/14597 0.0812 14597/347/351 1.028 R1 = 0.0920, wR2 = 0.2406 R1 = 0.1603, wR2 = 0.3002

a

The selected bond distances and angles are listed in Table S1 in the Supporting Information. Topology information for the compound was calculated by TOPOS 4.0.46

Gas Adsorption Measurements. The N2, CO2, CH4, C2H6, and C3H8 gas adsorption measurements were performed on Micromeritics instruments (Models ASAP 2420, ASAP 2020, and 3-Flex). Before measurement, the samples were activated by using the “outgas” function of the surface area analyzer for 10 h at 85 °C.

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RESULTS AND DISCUSSION Single-crystal X-ray diffraction analysis reveals that JLU-Liu33 crystallizes in the trigonal crystal system with the R3c space group. As shown in Figure 1a, JLU-Liu33 contains ternary secondary building units (SBUs): an organic SBU formed by 2connected ligand which show a V-shape; an inorganic SBU composed of classical Zn4O cluster and the other inorganic SBU composed of Zn4O cluster with terminal coordinated DMF. Figures 1b and 1c distinctly present the single net of the framework, which is similar to MOF-5.47 The space filling model of the single net can illustrate the window size of the channel along the [100] direction with a diameter of ∼11.4 Å × 11.6 Å, considering the van der Waals radius. The total framework structure is composed of two interpenetrating nets that are connected by weak C−H···π interactions, as evidenced by the observed distances between the H atoms of the H2DCPB and the centroids of the phenyl rings of 3.49 and 3.67 Å (see Figure S5 in the Supporting Information). From the topology point of view, the Zn4O cluster, which is chelated by six carboxylate groups, can be simplified to be a 6-connected node with octahedral geometry, and the ligand can be simplified as linear rods. Therefore, the total structure of JLU-Liu33 can be classified into pcu net topology with a 6646

DOI: 10.1021/acs.inorgchem.7b00744 Inorg. Chem. 2017, 56, 6645−6651

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Figure 1. Single-crystal structure for JLU-Liu33: (a) topology simplification of ligand and metal cores; (b) single net of the framework; (c) the space-filling model of the channel for the single net along the [100] direction; (d) polyhedral view of the net; (e) the simplified pcu topology network. Color scheme: carbon = gray, oxygen = red, zinc = green. Guest molecules and H atoms have been omitted for the sake of clarity.

Schläfli symbol of (412.63) (see Figures 1d and 1e). Although the framework of JLU-Liu33 is similar to JUC-135,48 there are many differences between them, in terms of unit-cell parameters, interpenetration degrees, coordination environment, and so on (see Figure S6 and Table S2 in the Supporting Information). Because of these differences, JLU-Liu33 shows completely different properties from JUC-135. PXRD analysis was used to check the phase purity of the crystalline samples of Co-doped JLU-Liu33. As shown in Figure 2b, all the PXRD patterns of the Co-doped JLU-Liu33 compounds (JLU-Liu33L and JLU-Liu33H) coincide with the simulated pattern of parent material, which indicate that the Co-doped JLU-Liu33 compounds are isostructural to JLULiu33. Because of the fact that Zn and Co possess similarity Xray scattering factors and occupy the same place in the framework, single-crystal X-ray diffraction (SCXD) methods cannot determine the quantity of Co ions in the framework by site occupancy refinement. The ICP measurement indicates that ∼0.58 Co2+ was introduced into each Zn4O cluster for JLU-Liu33L and 1.04 Co2+ for JLU-Liu33H. With the increasing amount of Co2+, the crystals color changed from colorless to pink and then to blue, indicating the presence of Oh Co ions and increasing amount of Td Co ions. Meanwhile, the XPS data also indicate that Co2+ occupied the same place as Zn2+ in the framework of JLU-Liu33 (see Figure S14 in the Supporting Information). The above studies provided the evidence that Co ions were successfully introduced into the framework of JLU-Liu33. N2 adsorption analysis on the activated samples was performed at 77 K to study the porous property of JLULiu33. In Zhu’s work, CH2Cl2 was used as exchanged solvent,

Figure 2. (a) The results of ICP analysis of the series of JLU-Liu33 analogues; (b) PXRD patterns for the simulated JLU-Liu33 and the as-synthesized PXRD for JLU-Liu33, JLU-Liu33L, and JLU-Liu33H.

which make the activated sample partly collapse and result in classical type-I N2 adsorption isotherm.48 By contrast, the PXRD pattern of the activated JLU-Liu33 indicates that the sample will not collapse after soaking in CH3CN for 2 days (Figure S1 in the Supporting Information). Meanwhile, the solvent molecules can almost be removed, which can be seen 6647

DOI: 10.1021/acs.inorgchem.7b00744 Inorg. Chem. 2017, 56, 6645−6651

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surprise, up to a relative pressure of 0.89, a second abrupt increase is observed. The maximum adsorption amount reaches to 290 cm3 g−1, which is similar to JLU-Liu33. By contrast, JLU-Liu33H does not show breathing behavior up to 1 atm. As revealed by the isotherms, the breathing behavior of JLU-Liu33 can be tuned by introducing Co ions into Zn4O clusters. In addition, to corroborate our hypothesis that the gate opening effect of the materials is caused by the removal of coordinated DMF, the crystal was soaked in CH3CN for 5 days to remove excess DMF. However, the Fourier transform infrared spectrum (FT-IR) of the sample still shows a resonance at 1665 cm−1, which can be attributed to the CO stretch of DMF (Figure S5 in the Supporting Information). This confirmed that some coordinated DMF cannot be removed totally after solvent exchange. The amounts of C, H, and N of the materials after solvent exchange and N2 adsorption characterization are also performed (Table S4 in the Supporting Information). The result indicates that the remaining coordinated DMF will be shifted during the N2 adsorption measurement. Upon removal of DMF, a shift between two nets may happen and result in transformation of the framework, which was indicated by the shift of the peaks and the change of their intensity in the PXRD (see Figure S3 in the Supporting Information). In parallel work, Jaheon Kim’s group also found that, upon removal and addition of coordinated DMF, the degree of interpenetration of the framework will be changed and the material shows a dynamic behavior upon N2 adsorption. Those exhaustive parallel studies largely support our proposed mechanism.21 Some examples of interpenetrated MOFs that exhibit a gate opening effect are also listed in Table S5 in the Supporting Information. The CO2 adsorption properties at 195 K were carried out to further investigate the breathing performance. Similar to the N2 adsorption isotherm, JLU-Liu33 is also found to exhibit the breathing behavior upon CO2 (Figure 4a). In the first step, the adsorption amount of CO2 is ∼50 cm3 g−1 at P/P0 = 0.04, then it reached up to 205 cm3 g−1 in the second step. Similarly, the desorption part of the isotherm does not coincide with the

from the TGA data (Figure S4 in the Supporting Information). Interestingly, as shown in Figure 3, JLU-Liu33 exhibits an

Figure 3. N2 adsorption and desorption isotherms for JLU-Liu33 (purple), JLU-Liu33L (blue), and JLU-Liu33H (red) at 77 K.

unusual adsorption property, which shows two steps in the adsorption branch of the isotherm. At low pressure, the material adsorbs a small amount of N2. To our surprise, up to a relative pressure of 0.06, the amount of N2 adsorption suddenly increases to a saturated uptake of 319 cm3 g−1. The desorption part of the isotherm do not trace the adsorption process, resulting in a large hysteresis loop. This peculiar phenomenon reveals that a breathing behavior happens in the process of N2 adsorption, giving rise to a significant increase in volume. On the other side, JLU-Liu33L and JLU-Liu33H were also measured for N2 adsorption at 77 K. JLU-Liu33L exhibits three distinct steps, which are different from JLU-Liu33. It shows slight N2 uptake at low pressure. Up to a relative pressure of 0.12, the amount of N2 adsorption suddenly increases up to 110 cm3 g−1, which is much lower than that of JLU-Liu33. To our

Figure 4. CO2 sorption isotherms for (a) JLU-Liu33, (b) JLU-Liu33L, (c) JLU-Liu33H, and (d) the corresponding isosteric heats. 6648

DOI: 10.1021/acs.inorgchem.7b00744 Inorg. Chem. 2017, 56, 6645−6651

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Figure 5. (a) C2H6 and (b) C3H8 isotherms for JLU-Liu33 at 273 and 298 K under 1 bar.

Figure 6. (a) CO2 and CH4 adsorption isotherms for JLU-Liu33H at 298 K along with the dual-site Langmuir Freundlich (DSLF) fits. (b) CO2/ CH4 adsorption selectivity are calculated by ideal adsorption solution (IAST) at 298 K and 1 bar for JLU-Liu33H.

Liu33L, and JLU-Liu33H are 14 and 7 cm3 g−1, 25 and 13 cm3 g−1, and 17 and 8 cm3 g−1, respectively. The C2H6 uptake at 273 and 298 K under 1 bar for JLU-Liu33, JLU-Liu33L, and JLU-Liu33H are 41 and 33 cm3 g−1, 39 and 30 cm3 g−1, and 42 and 35 cm3 g−1, respectively. The C3H8 uptake at 273 and 298 K under 1 bar for JLU-Liu33, JLU-Liu33L, and JLU-Liu33H are 44 and 38 cm3 g−1, 42 and 31 cm3 g−1, and 43 and 31 cm3 g−1, respectively (see Figure 5, as well as Figures S9 and S10 and Table S6 in the Supporting Information). The amount of CH4, C2H6, and C3H8 adsorption changed inconspicuously as the amount of Co2+ in the framework increased. Interestingly, only JLU-Liu33 shows breathing behavior upon C2H6, and its gate opening pressures are P/P0 = 0.24 and 0.48 at 273 and 298 K, respectively (Figure 5). On the other hand, all these materials show breathing behavior upon C3H8 adsorption, and the gate opening pressures of JLU-Liu33, JLU-Liu33L, and JLU-Liu33H are as follows: P/P0 = 0.03 and 0.06; P/P0 = 0.039 and 0.264; P/P0 = 0.033 and 0.302 at 273 and 298 K, respectively (see Figure 5, as well as Figures S10a and S10b). The above analyses also indicated that the gate opening pressures of JLU-Liu33 for C2H6 and C3H8 could be tuned through doping Co ions into the framework. To evaluate the affinity of the interpenetrated MOFs for small molecules, the Qst of the series of JLU-Liu33 for small gases, which possess normal gas adsorption behavior (CH4 and C2H6) were calculated. The Qst of CH4 for JLU-Liu33, JLULiu33L, and JLU-Liu33H is 25.50, 24.05, and 26.90 kJ mol−1, respectively. The Qst of C2H6 for JLU-Liu33L and JLULiu33H is 36.2 and 34.6 kJ mol−1 (Figures S11 and S12 in the Supporting Information). Furthermore, in the interest of exploring the practical separate ability of JLU-Liu33 compounds, the selectivity of CO2/CH4 was calculated via ideal adsorption solution (IAST) which was carried out at a theoretical mode (CO2/CH4 = 0.05/ 0.95 and CO2/CH4 = 0.5/0.5) with the dual-site Langmuir

adsorption branch, resulting in a small hysteresis loop. As shown in Figure 4b, JLU-Liu33L also exhibits a dynamic response to CO2 sorption, but it shows three distinct steps, which is consistent with its N2 adsorption isotherm. The gate opening pressures of JLU-Liu33L are P/P0 = 0.02 and 0.3. However, JLU-Liu33H exhibits a highly reversible type-I isotherm, reaching a saturated uptake of 111 cm3 g−1, which is much lower than JLU-Liu33 and JLU-Liu33L (Figure 4c). The analysis data indicates that the skeleton of JLU-Liu33H will not change during the gas sorption, but the frameworks of JLU-Liu33 and JLU-Liu33L come to phase transition, which make the pores in the materials expand during the process of adsorption. In order to calculate the isosteric heat (Qst), the CO2 adsorption isotherm of the materials were examined at 273 and 298 K. The CO2 uptake at 273 and 298 K under 1 bar for JLU-Liu33, JLU-Liu33L, and JLU-Liu33H are 32 and 20 cm3 g−1, 48 and 32 cm3 g−1, and 61 and 39 cm3 g−1, respectively (see Figure S8 and Table S6 in the Supporting Information). Furthermore, at zero loading, the Qst of JLU-Liu33, JLULiu33L, and JLU-Liu33H are 33.9, 35.5, and 37.8 kJ mol−1, respectively (Figure 4d). All these Qst values are impressive and exceed many MOFs with Lewis basic sites (LBSs), such as JLULiu20 and ZTF-1, similar to that of NH2-MIL-53(Al).49−51 Such high Qst values are attributed to the narrow pores, and this character may make a contribution to molecular sieving. The above analysis data fully indicates that the adsorption amount and isosteric enthalpy values of JLU-Liu33 for CO2 will be improved with the increasing amount of Co ions in the framework. Lots of parallel examples also confirmed the fact that Co ions could make a contribution to improving the capacity of CO2 adsorption.40,52 The CH4, C2H6, and C3H8 isotherms for the three compounds then were also measured at 273 and 298 K. The CH4 uptake at 273 and 298 K under 1 bar for JLU-Liu33, JLU6649

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Freundlich (DSLF) equation to fit the data at 298 K and 1 bar (see Figure 6a, as well as Figures S13a and S13c in the Supporting Information). JLU-Liu33H shows relatively higher selectivity for CO2/CH4 than JLU-Liu33 and JLU-Liu33L (see Figure 6b, as well as Figures S13b and Figure S13d in the Supporting Information), which can reach up to 9.7 and 13.9. Meanwhile, it outperformed many reported MOFs with high selectivity for CO2 over CH4 (Table S6 in the Supporting Information).

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CONCLUSIONS

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ASSOCIATED CONTENT

REFERENCES

(1) Li, J.-R.; Kuppler, R. J.; Zhou, H.-C. Selective gas adsorption and separation in metal−organic frameworks. Chem. Soc. Rev. 2009, 38, 1477−1504. (2) Kreno, L. E.; Leong, K.; Farha, O. K.; Allendorf, M.; Van Duyne, R. P.; Hupp, J. T. Metal−organic framework materials as chemical sensors. Chem. Rev. 2012, 112, 1105−1125. (3) Hu, Z.; Deibert, B. J.; Li, J. Luminescent metal-organic frameworks for chemical sensing and explosive detection. Chem. Soc. Rev. 2014, 43, 5815−5840. (4) Allendorf, M. D.; Bauer, C. A.; Bhakta, R. K.; Houk, R. J. T. Luminescent metal−organic frameworks. Chem. Soc. Rev. 2009, 38, 1330−1352. (5) Lee, J.; Farha, O. K.; Roberts, J.; Scheidt, K. A.; Nguyen, S. T.; Hupp, J. T. Metal−organic framework materials as catalysts. Chem. Soc. Rev. 2009, 38, 1450−1459. (6) Czaja, A. U.; Trukhan, N.; Muller, U. Industrial applications of metal−organic frameworks. Chem. Soc. Rev. 2009, 38, 1284−1293. (7) Liu, B.; Wu, W.-P.; Hou, L.; Wang, Y.-Y. Four uncommon nanocage-based Ln-MOFs: Highly selective luminescent sensing for Cu2+ ions and selective CO2 capture. Chem. Commun. 2014, 50, 8731− 8734. (8) Liu, J.-Q.; Li, G.-P.; Liu, W.-C.; Li, Q.-L.; Li, B.-H.; Gable, R. W.; Hou, L.; Batten, S. R. Two Unusual Nanocage-Based Ln-MOFs with Triazole Sites: Highly Fluorescent Sensing for Fe3+ and Cr2O72−, and Selective CO2 Capture. ChemPlusChem 2016, 81, 1299−1304. (9) Eddaoudi, M.; Kim, J.; Rosi, N.; Vodak, D.; Wachter, J.; O’Keeffe, M.; Yaghi, O. M. Systematic design of pore size and functionality in isoreticular MOFs and their application in methane storage. Science 2002, 295, 469−472. (10) Furukawa, H.; Ko, N.; Go, Y. B.; Aratani, N.; Choi, S. B.; Choi, E.; Yazaydin, A. Ö .; Snurr, R. Q.; O’Keeffe, M.; Kim, J.; Yaghi, O. M. Ultrahigh porosity in metal−organic frameworks. Science 2010, 329, 424−428. (11) Deng, H.; Grunder, S.; Cordova, K. E.; Valente, C.; Furukawa, 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. (12) Schnobrich, J. K.; Koh, K.; Sura, K. N.; Matzger, A. J. A framework for predicting surface areas in microporous coordination polymers. Langmuir 2010, 26, 5808−5814. (13) Lin, X.; Telepeni, I.; Blake, A. J.; Dailly, A.; Brown, C. M.; Simmons, J. M.; Zoppi, M.; Walker, G. S.; Thomas, K. M.; Mays, T. J.; Hubberstey, P.; Champness, N. R.; Schröder, M. High capacity hydrogen adsorption in Cu(II) tetracarboxylate framework materials: the role of pore size, ligand functionalization, and exposed metal sites. J. Am. Chem. Soc. 2009, 131, 2159−2171. (14) Park, Y. K.; Choi, S. B.; Kim, H.; Kim, K.; Won, B.-H.; Choi, K.; Choi, J.-S.; Ahn, W.-S.; Won, N.; Kim, S.; Jung, D. H.; Choi, S.-H.; Kim, G.-H.; Cha, S.-S.; Jhon, Y. H.; Yang, J. K.; Kim, J. Crystal structure and guest uptake of a mesoporous metal−organic framework containing cages of 3.9 and 4.7 nm in diameter. Angew. Chem. 2007, 119, 8378−8381. (15) Schaate, A.; Roy, P.; Preuße, T.; Lohmeier, S. J.; Godt, A.; Behrens, P. Porous interpenetrated Zirconium−organic frameworks (PIZOFs): A chemically versatile family of metal−organic frameworks. Chem.Eur. J. 2011, 17, 9320−9325. (16) Liu, J.; Liu, G.; Gu, C.; Liu, W.; Xu, J.; Li, B.; Wang, W. Rational synthesis of a novel 3,3,5-c polyhedral metal−organic framework with high thermal stability and hydrogen storage capability. J. Mater. Chem. A 2016, 4, 11630−11634. (17) Nijem, N.; Wu, H.; Canepa, P.; Marti, A.; Balkus, K. J.; Thonhauser, T.; Li, J.; Chabal, Y. J. Tuning the gate opening pressure of metal−organic frameworks (MOFs) for the selective separation of hydrocarbons. J. Am. Chem. Soc. 2012, 134, 15201−15204. (18) Shekhah, O.; Wang, H.; Paradinas, M.; Ocal, C.; Schupbach, B.; Terfort, A.; Zacher, D.; Fischer, R. A.; Woll, C. Controlling

In summary, a flexibly interpenetrated metal−organic framework (MOF) (JLU-Liu33) have been successfully synthesized, and another two isomorphic compounds (JLU-Liu33L and JLU-Liu33H) were achieved by introducing different contents of cobalt ions into Zn4O metal clusters. The above studies clearly demonstrated that JLU-Liu33 show a gate opening effect on the sorption of N2 and CO2 at low temperature, and C2H6 and C3H8 at 273 and 298 K. Notably, by doping other metal ions into metal clusters, the gate opening pressure of the isomorphic materials can be modulated. Meanwhile, with the increasing of Co content, the adsorption amount and its isosteric enthalpy values for CO2 will be improved. In addition, JLU-Liu33H also exhibited high selectivity for CO2 over CH4. These significant results may inspire more researchers to engage in studying of flexibly interpenetrated MOFs, and we will put more attention to understand the structural changes during the gas sorption.

* Supporting Information S

The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.inorgchem.7b00744. Additional crystal structure diagrams, IR, PXRD, elemental analyses (C, H, and N), and TGA patterns (PDF) Accession Codes

CCDC 1517774 contains the supplementary crystallographic data for this paper. These data can be obtained free of charge via www.ccdc.cam.ac.uk/data_request/cif, or by emailing data_ [email protected], or by contacting The Cambridge Crystallographic Data Centre, 12, Union Road, Cambridge CB2 1EZ, U.K. Fax: +44 1223 336033.

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AUTHOR INFORMATION

Corresponding Authors

*Fax: +86-431-85168624. E-mail: [email protected] (L. Zhang). *Fax: +86-431-85168624. E-mail: [email protected] (Y. Liu). ORCID

Yunling Liu: 0000-0001-5040-6816 Notes

The authors declare no competing financial interest.

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ACKNOWLEDGMENTS This work was supported by the National Natural Science Foundation of China (Nos. 21373095 21371067, and 21621001). 6650

DOI: 10.1021/acs.inorgchem.7b00744 Inorg. Chem. 2017, 56, 6645−6651

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Inorganic Chemistry interpenetration in metal-organic frameworks by liquid-phase epitaxy. Nat. Mater. 2009, 8, 481−484. (19) Yang, S.; Lin, X.; Lewis, W.; Suyetin, M.; Bichoutskaia, E.; Parker, J. E.; Tang, C. C.; Allan, D. R.; Rizkallah, P. J.; Hubberstey, P.; Champness, N. R.; Thomas, K. M.; Blake, A. J.; Schröder, M. A partially interpenetrated metal−organic framework for selective hysteretic sorption of carbon dioxide. Nat. Mater. 2012, 11, 710−716. (20) Choi, S. B.; Furukawa, H.; Nam, H. J.; Jung, D.-Y.; Jhon, Y. H.; Walton, A.; Book, D.; O’Keeffe, M.; Yaghi, O. M.; Kim, J. Reversible interpenetration in a metal−organic framework triggered by ligand removal and addition. Angew. Chem., Int. Ed. 2012, 51, 8791−8795. (21) Li, X.; Chen, X.; Jiang, F.; Chen, L.; Lu, S.; Chen, Q.; Wu, M.; Yuan, D.; Hong, M. The dynamic response of a flexible indium based metal-organic framework to gas sorption. Chem. Commun. 2016, 52, 2277−2280. (22) Liu, J.-Q.; Wu, J.; Li, F.-M.; Liu, W.-C.; Li, B.-H.; Wang, J.; Li, Q.-L.; Yadav, R.; Kumar, A. Luminescent sensing from a new Zn(II) metal-organic framework. RSC Adv. 2016, 6, 31161−31166. (23) Aggarwal, H.; Das, R. K.; Bhatt, P. M.; Barbour, L. J. Isolation of a structural intermediate during switching of degree of interpenetration in a metal-organic framework. Chem. Sci. 2015, 6, 4986−4992. (24) Ferey, G.; Serre, C. Large breathing effects in three-dimensional porous hybrid matter: Facts, analyses, rules and consequences. Chem. Soc. Rev. 2009, 38, 1380−1399. (25) Wei, Y.-S.; Chen, K.-J.; Liao, P.-Q.; Zhu, B.-Y.; Lin, R.-B.; Zhou, H.-L.; Wang, B.-Y.; Xue, W.; Zhang, J.-P.; Chen, X.-M. Turning on the flexibility of isoreticular porous coordination frameworks for drastically tunable framework breathing and thermal expansion. Chem. Sci. 2013, 4, 1539−1546. (26) Llewellyn, P. L.; Maurin, G.; Devic, T.; Loera-Serna, S.; Rosenbach, N.; Serre, C.; Bourrelly, S.; Horcajada, P.; Filinchuk, Y.; Férey, G. Prediction of the Conditions for Breathing of Metal Organic Framework Materials Using a Combination of X-ray Powder Diffraction, Microcalorimetry, and Molecular Simulation. J. Am. Chem. Soc. 2008, 130, 12808−12814. (27) Wang, C.-C.; Tseng, S.-M.; Lin, S.-Y.; Liu, F.-C.; Dai, S.-C.; Lee, G.-H.; Shih, W.-J.; Sheu, H.-S. Assemblies of two mixed-ligand coordination polymers with two-dimensional metal−organic frameworks constructed from M(II) ions with croconate and 1,2-Bis-(4pyridyl)ethylene (M = Cd and Zn). Cryst. Growth Des. 2007, 7, 1783− 1790. (28) Wang, S.; Zhao, T.; Li, G.; Wojtas, L.; Huo, Q.; Eddaoudi, M.; Liu, Y. From metal−organic squares to porous zeolite-like supramolecular assemblies. J. Am. Chem. Soc. 2010, 132, 18038−18041. (29) Belof, J. L.; Stern, A. C.; Eddaoudi, M.; Space, B. On the mechanism of hydrogen storage in a metal−organic framework material. J. Am. Chem. Soc. 2007, 129, 15202−15210. (30) Nijem, N.; Wu, H.; Canepa, P.; Marti, A.; Balkus, K. J.; Thonhauser, T.; Li, J.; Chabal, Y. J. Tuning the Gate Opening Pressure of Metal−Organic Frameworks (MOFs) for the Selective Separation of Hydrocarbons. J. Am. Chem. Soc. 2012, 134, 15201−15204. (31) Wang, Z.; Cohen, S. M. Modulating metal−organic frameworks to breathe: A postsynthetic covalent modification approach. J. Am. Chem. Soc. 2009, 131, 16675−16677. (32) Murdock, C. R.; McNutt, N. W.; Keffer, D. J.; Jenkins, D. M. Rotating phenyl rings as a guest-dependent switch in two-dimensional metal−organic frameworks. J. Am. Chem. Soc. 2014, 136, 671−678. (33) Seki, K. Dynamic channels of a porous coordination polymer responding to external stimuli. Phys. Chem. Chem. Phys. 2002, 4, 1968−1971. (34) Serre, C.; Millange, F.; Thouvenot, C.; Noguès, M.; Marsolier, G.; Louër, D.; Férey, G. Very large breathing effect in the first nanoporous Chromium(III)-Based Solids: MIL-53 or CrIII(OH)· {O2C−C6H4−CO2}·{HO2C−C6H4−CO2H}x·H2Oy. J. Am. Chem. Soc. 2002, 124, 13519−13526. (35) Bourrelly, S.; Moulin, B.; Rivera, A.; Maurin, G.; DevautourVinot, S.; Serre, C.; Devic, T.; Horcajada, P.; Vimont, A.; Clet, G.; Daturi, M.; Lavalley, J.-C.; Loera-Serna, S.; Denoyel, R.; Llewellyn, P.

L.; Férey, G. Explanation of the adsorption of polar vapors in the highly flexible metal organic framework MIL-53(Cr). J. Am. Chem. Soc. 2010, 132, 9488−9498. (36) Bourrelly, S.; Llewellyn, P. L.; Serre, C.; Millange, F.; Loiseau, T.; Férey, G. Different adsorption behaviors of methane and carbon dioxide in the isotypic nanoporous metal terephthalates MIL-53 and MIL-47. J. Am. Chem. Soc. 2005, 127, 13519−13521. (37) Mukherjee, G.; Biradha, K. Modulation of breathing behavior of layered coordination polymers via a solid solution approach: The influence of metal ions on sorption behavior. Chem. Commun. 2014, 50, 670−672. (38) Kozachuk, O.; Meilikhov, M.; Yusenko, K.; Schneemann, A.; Jee, B.; Kuttatheyil, A. V.; Bertmer, M.; Sternemann, C.; Pöppl, A.; Fischer, R. A. A solid-solution approach to mixed-metal metal−organic frameworksDetailed characterization of local structures, defects and breathing behaviour of Al/V frameworks. Eur. J. Inorg. Chem. 2013, 2013, 4546−4557. (39) Evans, J. D.; Sumby, C. J.; Doonan, C. J. Post-synthetic metalation of metal-organic frameworks. Chem. Soc. Rev. 2014, 43, 5933−5951. (40) Zhai, Q.-G.; Bu, X.; Mao, C.; Zhao, X.; Feng, P. Systematic and dramatic tuning on gas sorption performance in heterometallic metal− organic frameworks. J. Am. Chem. Soc. 2016, 138, 2524−2527. (41) Han, Y.; Li, J.-R.; Xie, Y.; Guo, G. Substitution reactions in metal−organic frameworks and metal−organic polyhedra. Chem. Soc. Rev. 2014, 43, 5952−5981. (42) Brozek, C. K.; Dinca, M. Cation exchange at the secondary building units of metal-organic frameworks. Chem. Soc. Rev. 2014, 43, 5456−5467. (43) Evans, J. D.; Sumby, C. J.; Doonan, C. J. Post-synthetic metalation of metal-organic frameworks. Chem. Soc. Rev. 2014, 43, 5933−5951. (44) Lalonde, M.; Bury, W.; Karagiaridi, O.; Brown, Z.; Hupp, J. T.; Farha, O. K. Transmetalation: Routes to metal exchange within metalorganic frameworks. J. Mater. Chem. A 2013, 1, 5453−5468. (45) Sheldrick, G. M. Acta Crystallogr., Sect. A: Found. Crystallogr. 2008, 64, 112−122. (46) Blatov, V. A.; Shevchenko, A. P.; Proserpio, D. M. Applied topological analysis of crystal structures with the program package Topos Pro. Cryst. Growth Des. 2014, 14, 3576−3586. (47) Li, H.; Eddaoudi, M.; O’Keeffe, M.; Yaghi, O. M. Design and synthesis of an exceptionally stable and highly porous metal-organic framework. Nature 1999, 402, 276−279. (48) He, H.; Song, Y.; Sun, F.; Bian, Z.; Gao, L.; Zhu, G. A porous metal-organic framework formed by a V-shaped ligand and Zn(II) ion with highly selective sensing for nitroaromatic explosives. J. Mater. Chem. A 2015, 3, 16598−16603. (49) Couck, S.; Denayer, J. F. M.; Baron, G. V.; Rémy, T.; Gascon, J.; Kapteijn, F. An amine-functionalized MIL-53 metal−organic framework with large separation power for CO2 and CH4. J. Am. Chem. Soc. 2009, 131, 6326−6327. (50) Liu, B.; Yao, S.; Shi, C.; Li, G.; Huo, Q.; Liu, Y. Significant enhancement of gas uptake capacity and selectivity via the judicious increase of open metal sites and Lewis basic sites within two polyhedron-based metal-organic frameworks. Chem. Commun. 2016, 52, 3223−3226. (51) Panda, T.; Pachfule, P.; Chen, Y.; Jiang, J.; Banerjee, R. Amino functionalized zeolitic tetrazolate framework (ZTF) with high capacity for storage of carbon dioxide. Chem. Commun. 2011, 47, 2011−2013. (52) Botas, J. A.; Calleja, G.; Sanchez-Sanchez, M.; Orcajo, M. G. Cobalt doping of the MOF-5 framework and its effect on gasadsorption properties. Langmuir 2010, 26, 5300−5303.

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DOI: 10.1021/acs.inorgchem.7b00744 Inorg. Chem. 2017, 56, 6645−6651