Interpenetrated structures appeared in supramolecular cages, MOFs, COFs

Coordination Chemistry Reviews 389 (2019) 119–140

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Coordination Chemistry Reviews journal homepage: www.elsevier.com/locate/ccr

Review

Interpenetrated structures appeared in supramolecular cages, MOFs, COFs Rongmei Zhu, Jiawei Ding, Ling Jin, Huan Pang ⇑ School of Chemistry and Chemical Engineering, Institute for Innovative Materials and Energy, Yangzhou University, Yangzhou 225009, Jiangsu, PR China

a r t i c l e

i n f o

Article history: Received 24 November 2018 Accepted 2 March 2019

Keywords: Interpenetrated structure Cage MOF COF

a b s t r a c t The construction of interpenetrated structures was originally achieved via the self-assembly process by an accidental discovery. Nevertheless, this type of interpenetrated structure exhibits fascinating properties and outstanding applications, such as catalysis, molecule recognition and separation, selective gas adsorption. Recent years, several groups focus on the development of such interesting structures and explore their potential applications in different areas. Herein, interpenetrated structures including interpenetrated supramolecular cages, MOFs and COFs are discussed in this manuscript. Concrete examples in recent years are reviewed to illustrate their synthetic strategies, structural features and potential applications. We would like to provide an overview on the developments in the area of interpenetrated topologies and hope this review can shed some light on the further investigation of interpenetrated architectures and provide some insight on their applications. Ó 2019 Elsevier B.V. All rights reserved.

Contents 1. 2. 3. 4. 5.

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . Interpenetrated supramolecular cages . . . . . . Interpenetrated metal organic frameworks . . Interpenetrated covalent organic frameworks Conclusion and outlook . . . . . . . . . . . . . . . . . . Acknowledgements . . . . . . . . . . . . . . . . . . . . . Appendix A. Supplementary data . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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1. Introduction During the last few decades, various novel structures such as supramolecular cages (SCs) [1–7], metal organic frameworks (MOFs) [8–13] and covalent organic frameworks (COFs) [14–17] (Fig. 1) have been reported. Since related reviews have separately compared two of these three architectures in detail [18,19], herein, we would briefly discuss the commonalities and differences between SCs, MOFs and COFs. SCs and MOFs are formed from coordinative assembly between metals and organic ligands, while COFs are constructed from pure organic units via strong covalent bonds. Due to the robustness of ⇑ Corresponding author. E-mail addresses: [email protected], [email protected] (H. Pang). https://doi.org/10.1016/j.ccr.2019.03.002 0010-8545/Ó 2019 Elsevier B.V. All rights reserved.

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covalent bonds compared to coordination bonds, COFs indicate a harsher structural regularity than SCs and MOFs. From the view of the networks, SCs possess a discrete system with finite networks, which usually are soluble. However, MOFs and COFs encompass persistent porous architectures with infinite arrays, which are insoluble in normal solvents. SCs are oftentimes constructed in solution with all intermediate species and the ultimate product soluble, which can be monitored all through the assembly process. Furthermore, the kinetic intermediates can be detected by some common techniques, such as NMR and mass spectroscopy. Nevertheless, MOFs and COFs are generally prepared in sealed autoclaves via the typical solvothermal strategy. The thermodynamic product is exclusively obtained that is also presented as precipitation during the preparation, which cannot dissolve in common solvents. As a result, it is diffi-

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cult to monitor the intermediates and understand the formation process. When it comes to the suitable single crystals, MOFs and COFs could only crystalize during the preparation because of the poor solubility. SCs, which are easier to adopt the traditional methods of crystallization, can be recycled and recrystallize under different conditions until high quality of crystals are obtained. In addition, SCs can be characterized by solution-based techniques, which can reveal their specified components and structures. However, MOFs and COFs can only be characterized by solid-based techniques, such as powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, which would provide the surface morphology. SCs, MOFs and COFs display various properties attributed to their interesting structures, but their applications are limited due to the low stability of the monomeric structures. The interpenetration of structures can increase their stability and provide with some interesting applications. Interpenetrated supramolecular cages (iSCs) illustrate many applications such as delivery [20], recognition [21], catalysis [22], separation [23], and gas storage [24]. Meanwhile, interpenetrated MOFs (iMOFs) present some interesting properties, such as selective guest capture [25], stepwise gas sorption [26], dye removal [27], thermal transport [28]. Interpenetrated COFs (iCOFs) can be applied in gas adsorption [14,29] and CO2 capture [30]. The construction of interpenetrated structures was originally found by accident in the self-assembly process. The interpenetrated structures present particular functions that are not obtained by monomeric structures. In addition, interpenetrated structures have drawn much interest, since they can provide multiple cavities, allowing for the binding of additional species [31–36]. The Fujita group reported the first interpenetrated supramolecular structure formed from rigid ligands [38]. In general, the simplest form of a mechanical interlocking structure is [2]catenane, which is linked together by two macrocycles. However, the interesting interpenetrated catenane reported by Fujita consists not of two interlocked rings but of two cages. Many other strategies and designs can form such interpenetrated structures. In theory, substances can be entangled in a multiply interpenetrated way, but it is difficult to predict the successful formation. In 2009, Beer and colleagues prepared a multiply interpenetrated system formed from covalent entities [39]. The effective utilization of chemical templates has made it possible to synthesize interpenetrated structures. Interestingly, the Kuroda group converted interpenetrated double cage into monomeric cages under the help from the anion template and both of the two structures could be transformed into each other [40]. In this review, we will introduce and summarize recent research of interpenetrated structures, such as iSCs, iMOFs, iCOFs. We will focus on the design, characterization as well as potential application of these specific architectures. We would like to give an overview of the progress on interpenetrated structures and reveal their corresponding application prospects.

However, the length of the ligands and the degree of their bending could affect the formation of the cage. It is still a challenge to construct 3D supramolecular cages. Therefore, strategies that can effectively obtain 3D supramolecular cages are urgently needed. Self-assembly appears to be a simple and effective method of obtaining supramolecular cages. To better reveal the iSCs, we would briefly introduce the monomeric cage first. Since the first 3D monomeric cage was reported by the Fujita group [48], attention has increasingly shifted from topological structures toward functional implementations. The typical monomeric cage [Pd6L14] (Fig. 2a), which is selfassembled from 2,4,6-tri(4-pyridyl)-1,3,5-triazine (L1) and Pd (ONO2)2, was reported by the Fujita group in 2002 [49]. In spite of the unique structure, cage [Pd6L14] (a) can encapsulate a number of neutral molecules in the cavity with a strong binding constant. As shown in Fig. 2b, cage [Pd6L14] exhibits different binding behaviors depending on the size of the guest molecules. The molecules are bound in three different forms according to their size and shape: tetrahedral 1:4 complexation, orthogonal 1:2 complexation, and a simple 1:1 complexation. In addition, the cavity in such a cage can serve as the reaction vessel for a special reaction, which does not take place under normal conditions. Cage [Pd6L14] could successfully catalyze the photoaddition reaction between fluoranthene and maleimide derivatives (Fig. 2c) [3]. Such a monomeric cage is one of the simplest supramolecular patterns. A special case of molecular entanglement is interpenetration, where two or more discrete monomeric species are interlocked without direct bonding connections between each other. Due to the remarkable architectures of iSCs, self-assembled interpenetrated structures have been subsequently studied by chemists [50,51]. The topologies and characterizations in double cages have attracted much attention since the first interlocked supramolecule was reported by Fujita and co-workers [38]. In their work, the selfassembly of interlocked complex is attributed to the attractive p-p stacking between the two separate cages that are constructed from two different tridentate ligands and square-planar coordinated metal cations (PdII or PtII) (Fig. 3). The first iSC of [Pd4L28] stoichiometry was reported by Sekiya and Kuroda based on a conformationally flexible bismonodentate ligand L2 in 2008 (Fig. 4a) [52]. Based on their research, the Clever group synthesized the iSC [BF4@Pd4L38] (Fig. 4b) [53]. Ligand L3 forms a monomeric cage as an active intermediate with PdII, which then quantitatively converts into the interpenetrated dimers in which three anions sandwiched between the four metal centers [54,55]. Interestingly, this iSC was found to be a strong acceptor for halide anions (Cl
or Br
). As illustrated, in the iSC [2Cl + BF4@Pd4L38], smaller halide anions occupy the outer two pockets, and the BF
4 anion occupies the inner pocket. Furthermore, a modification of the ligand backbone was found to yield a similar double cage system but displayed a very different anion preference. The iSC [Cl@Pd4L48], featuring a small cavity of the central pocket, is able to incorporate larger guest

2. Interpenetrated supramolecular cages 3D supramolecular cages are generally constructed from metal ions and organic ligands. They present many outstanding applications because of their interesting structures and internal cavities [41]. Hitherto, cages have shown applications in fields such as selective anion recognition [42], the sequestration of hazardous substances [43], drug delivery [44], and the stabilization of reactive reagents and intermediates [45]. They have drawn substantial attention due to their diverse applications as sensors, nanoreactors, delivery vehicles, gas storage and separation materials [46,47].

Fig. 1. Topologies of (a) monomeric unit of a [Pd2L4] coordination cage; (b) interpenetrated supramolecular cage; (c) interpenetrated MOF or COF. Reproduced with permission from Ref. [37]. Copyright 2016, Wiley-VCH.

R. Zhu et al. / Coordination Chemistry Reviews 389 (2019) 119–140

molecules, such as ReO
4 , into the two outer pockets (Fig. 4c). In comparison, the size of the central cavity plays a pivotal role in encapsulating different anions, which reveals the application of anion selectivity in iSCs. Later on, Clever and colleagues reported a similar interpenetrated double cage based on the acridone backbone that initially enclosed tetrafluoroborate anions in all three consecutive binding pockets. After activation by halide anions, it is able to bind neutral guest molecules such as benzene, cyclohexane and norbornadiene (Fig. 5) [53,56]. In comparison the crystal structures of [3BF4@Pd4L58]5+ with [2Cl + benzene@Pd4L58]5+ from Fig. 5c and d, a benzene molecule occupies the central pocket substituting the BF
4 anion obviously in the chloride-activated cage. A further study examined the binding affinity and kinetics for benzene versus cyclohexane into the chloride-activated [Pd4L58], as well as for norbornadiene in the chloride-activated [Pd4L58] compared with the bromide-activated [Pd4L58] [57]. It was observed that benzene is incorporated faster than cyclohexane,

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but the latter guest binds stronger than the former one. It was also observed that the absorption of norbornadiene in the chlorideactivated cage is thermodynamically favored and 12 times faster than that in the bromide-activated cage (Fig. 5b). The Clever group further published a systematic study of over 50 small neutral guest molecules encapsulated in the double cage ([3BF4@Pd4L58]5+) that reveals the effects of the size, shape, and chemical properties of the guest molecules on the binding affinity [58]. In these systems, the triggered binding of small molecules opens up possibilities for applications in supramolecular sensing, signal transduction, and even catalysis under external control. In the same group, three similar ligands were designed to obtain iSCs [37,59,60] based on the backbone of phenothiazine. All the cages are structurally similar and possess the same topology (Fig. 6a). Furthermore, Clever and co-workers were able to obtain photo-powered charge separation in a supramolecular system based on a mixed-ligand cage formed from the ligand L6 as the redox-active chromophore and the ligand L9 as the electron accep-

Fig. 2. (a) The synthesis of cage [Pd6L14]; (b) guests molecules intercalated in three different manners into cage [Pd6L14]; (c) [2+2] photoaddition reaction of fluoranthene with maleimide derivatives in cage [Pd6L14]. (a and b) Reproduced with permission from Ref. [49]. Copyright 2002, American Chemical Society. (c) Reproduced with permission from Ref. [3]. Copyright 2008, American Chemical Society.

Fig. 3. Self-assembly of the first interlocked double cage. Reproduced with permission from Ref. [38]. Copyright 1999, Nature Publishing.

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Fig. 4. (a) The first reported interpenetrated double cage [Pd4L28]; (b) self-assembly of the double cage [BF4@Pd4L38]; (c) self-assembly of the double cage [Cl@Pd4L48]. Copyright 2013, American Chemical Society.

Fig. 5. (a) The assembly of cage [3BF4@Pd4L58]5+ and the uptake of halide anions; (b) comparison of uptake kinetics and thermodynamics with different neutral guests and different halides; X-ray structures of (c) [3BF4@Pd4L58]5+ and (d) [2Cl + benzene@Pd4L58]6+, Color code: benzene, red; Cl
, yellow; BF
4 , orange red. Reproduced with permission from Ref. [56]. Copyright 2015, American Chemical Society.

tor (Fig. 6b) [61]. Interestingly, light excitation of the donor in these mixed cages leads to a charge separated state, revealed by femtosecond time-resolved absorption spectroscopy (Fig. 6c and d). The method of supramolecular assembly based on interpenetrated cage structures presented herein may promote the development of new materials for photoactive layers with controlled morphologies in future photovoltaic devices.

In the examples aforementioned, the iSCs are the thermodynamically stable products while most monomeric cages are kinetically intermediate products besides the cage [Pd2L44] due to the steric hindrance from the backbone. To realize the formation of thermodynamically stable monomeric cages and the visible transfer between the monomeric cages and their corresponding iSCs, Clever and colleagues designed and successfully synthesized a

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Fig. 6. (a) Self-assembly of three iSCs based on the phenothiazine backbones; (b) mixed iSCs constructed from ligands L6 and L9; (c) photoexcitation of the mixed iSCs leads to light-induced charge separation as evidenced by (d) time-resolved pump-probe spectroscopy. (a) Reproduced with permission from Ref. [37]. Copyright 2016, Wiley-VCH. (b–d) Reproduced with permission from Ref. [61]. Copyright 2016, American Chemical Society.

Fig. 7. (a) Above, the scheme of assembly of the monomeric cage [Pd2L104]4+, the halide-templated double cage [3X@Pd4L108]5+ (X = Cl
, Br
), and the triple catenane [(PdX2)6L106]0; below, X-ray structures of the monomeric cage [Pd2L104]4+, DFT-calculated structure for the double cage [3Cl@Pd4L108]5+, and X-ray structures of the triplecatenane [(PdBr2)6L106]0; (b) assembly and the view of single-crystal X-ray structures of the monomeric peanut cage [Pd3L114]6+ and interpenetrated double cage [5X@Pd6L118]7+; (c) top and side view of disc-shaped molecular model composed of 32 [5Cl@Pd6L118]7+ cages and the interaction with short double stranded DNA. (a) Reproduced with permission from Ref. [62]. Copyright 2016, Wiley-VCH. (b-c) Reproduced with permission from Ref. [63]. Copyright 2018, Wiley-VCH.

shorter bis-pyridyl ligand L10 compared with ligand L3, L5 and L6 based on a carbazole backbone [62]. It was demonstrated that a thermodynamically stable monomeric cage took shape from ligand L10 with metal cations in the existence of BF
4 anions rather than a double cage structure. Inter-

estingly, with the addition of halide anions, an interpenetrated double cage encapsulating the halide anions in all three of its cavities is formed. The conversion between the thermodynamically stable monomeric cage and iSC is achieved via adjusting the length of the ligand. Surprisingly, adding excess the same halide anions

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Fig. 8. Self-assembly of interpenetrated cage [Ag6L124]6+. Reproduced with permission from Ref. [40,65,66]. Copyright 2012, American Chemical Society.

Fig. 9. (a) The synthesis of interpenetrated double cage [3NO3@Pd4L28]5+ and the interconversion between the monomeric cage and interpenetrated cage; (b) the formation of interlocked cage [Pd6(tmen)6L134]12+ and reversible transformation between [Pd6(tmen)6L134]12+ and coupled [Pd6(tmen)6L134]12+. (a) Reproduced with permission from Ref. [64]. Copyright 2011, the Royal Society of Chemistry. (b) Reproduced with permission from Ref. [67]. Copyright 2014, American Chemical Society.

Fig. 10. (a) and (b) The scheme of the formation of monomeric cage and interpenetrated cage as well as their separation and conversion under different conditions. Reproduced with permission from Ref. [69]. Copyright 2016, the Royal Society of Chemistry.

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Fig. 11. Robust iMOF shows multiple guest-binding functionalities. Reproduced with permission from Ref. [87]. Copyright 2016, Wiley-VCH.

Fig. 12. (a) Self-assembly and interpenetration in 3D MOF materials; (b) comparison of low-pressure CO2, CH4, N2, Ar, O2 and H2 sorption isotherms at 195 K. Reproduced with permission from ref.[89]. Copyright 2016, Wiley-VCH.

led to a second structural transformation, a triple catenane link structure is formed (Fig. 7a). It is found that concentration also plays a significant role in the diversification of structural or mechanistic behaviors in intricate supramolecular systems. Subsequently, a longer tris-monodentate ligand L11 compared to the bis-monodentate ligand L10 was designed by Clever and co-workers. They used the same method to construct the peanutshaped cage [Pd3L114], which could be quantitatively converted into its interpenetrated cage [5Cl@Pd6L118] (Fig. 7b) [63]. The single-crystal X-ray structures of cages are shown in Fig. 7b. It is demonstrated by the small angle neutron scattering (SANS) experiment that aggregates of [5Cl@Pd6L118] were formed, which display as a disc-like shape. Compared to the single complex, one aggregate is made up of 32 components, which is much bigger and highly charged. Interestingly, the cage aggregates could be broken up by polyanionic DNA in aqueous solution and the precipitation of cage-DNA salt was discovered upon heating the mixture. The interaction between supramolecular cages and DNA revealed in this publication may provide some insights with the application of supramolecular chemistry into the research of artificial histone mimics. In 2011, the Hardie group reported an interpenetrated cage [Ag6L124]X6, which is constructed from the tris-monodentate

ligand L12 and silver cations (Fig. 8) [64]. In the presence of three equivalents of AgI, the monomeric complex Ag3L122 was formed. However, upon adding three equivalents more of AgI, the iSC [Ag6L124]X6 was emerged due to the short and flexible spacers between the scaffold and the coordinating pyridines. In addition to the iSCs introduced above from Clever group, there are more iSCs studied by other groups. Different from the examples mentioned above, monomeric cages and double cages in the following can be transformed into each other under different conditions, rather than one-way synthesis of double cages from monomeric cages. The first iSC [Pd4L28] based on the monodentate ligand L2 has been introduced in the above. In the same year, Kuroda and colleagues constructed another iSC [3NO3@Pd4L28]5+ with the same

ligand (Fig. 9a) [40,65,66]. Among the anions (NO
3 , BF4 , PF6 and

OTf ) studied, the affinity of NO3 was the highest due to electrostatic interaction and its Lewis basicity. Under the addition of anion ONs
, monomerization occurred and the double cage can converted back to the monomeric cage. Interestingly, when NO
3 was added, dimerization occurred again and the monomeric cages were converted back into the double cage [3NO3@Pd4L28]5+. In their research, the monomeric cages and interpenetrated cage can be converted to each other by changing anionic molecules (Fig. 9a).

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Fig. 13. (a) Synthesis of the SUMOFs; (b) left: non-interpenetrated framework of SUMOF-2-4, respectively; right: crystal structures of the doubly interpenetrated frameworks of SUMOF-2-4, respectively; (c) the absorption of CO2 at 273 K for SUMOFs. Reproduced with permission from Ref. [25]. Copyright 2012, the Royal Society of Chemistry.

Fig. 14. (a) The 3D framework of ECUT-30; (b) view of the four-fold interpenetration; (c) the CO2 adsorption isotherm of ECUT-30 at 195 K; (d) the adsorption isotherms of C2H2/C2H4/CO2 at 293 K under UV-irradiation or at ambient, respectively; (e-g) adsorption selectivity of C2H2/C2H4, C2H2/CO2 and C2H2/C2H4 at 293 K for the samples of ECUT30 under UV and ambient, respectively. Reproduced with permission from Ref. [92]. Copyright 2012, the Royal Society of Chemistry.

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Fig. 15. (a) Left, coordination environment of the metal ions in DMOF. Color code: C green, N blue, O red, Zn purple, S yellow, F orange. Middle, 3D dia net structure of DMOF along b axis. Right, fivefold interpenetrating dia net structure of DMOF along b axis; (b) color change of DMOF under UV irradiation and visible light. Reproduced with permission from Ref. [94]. Copyright 2014, Wiley-VCH.

Fig. 16. (a) 2-Fold interpenetrated 3D-frameworks of CuII-MOF; (b) N2 adsorption-desorption isotherms; (c) H2 uptake isotherm of Cu-MOPF at 77 K and one bar; (d) the adsorption isotherms of CO2 and CH4 for Cu-MOPF at 273 K and 1 bar. Reproduced with permission from Ref. [68]. Copyright 2018, Wiley-VCH.

In 2014, the Mukherjee group reported the construction of a new iSC [Pd6(tmen)6L134]12+, which was self-assembled from a cis-blocked [Pd(tmen)](NO3)2 salt and 1,3,5-tris[(E)-2-(pyridin-3yl)vinyl]benzene (Fig. 9b) [67]. An examination of the crystal packaging showed that a pair of olefin double bonds in adjacent cages are arranged in parallel with each other in a perfect head-to-tail manner, which meets the topochemical standard of photoreactivity established by Schmidt [68]. Under sunlight or after irradiation with UV light, two adjacent cages undergo a [2+2] cycloaddition reaction resulting of Married Couple. Furthermore, Married Couple can disassemble back to two separate double cages under thermal conditions in water (Fig. 9b). In principle, this kind of reversible

photoreactive system could potentially be extended to develop materials for photoswitches and optical data storage devices. In 2016, Barboiu and colleagues reported a universal system in which discrete monomeric and dimeric cages can be obtained simultaneously under different reaction conditions (Fig. 10) [69]. When the ligand is treated with different solvents, different results can be obtained. An insoluble monomeric cage [Pd2L144]4+ and a soluble interpenetrated cage [3BF4@Pd4L148]5+ can be obtained when the ligand reacts with [Pd(CH3CN)4](BF4)2 in acetonitrile (Fig. 10a). When the reaction takes place in more polar solution, such as DMF or DMSO, the interpenetrated cage [3BF4@Pd4L148]5+ was dissolved and only monomeric cage [Pd2L144]4+ were formed.

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Fig. 17. (a) The 2D cage-like MOF Cu-bpp-MOF and 3D iMOF Cu-bipy-MOF; (b) CO2 and N2 adsorption isotherms of compound Cu-bpp-MOF; (c) and (d) CO2 adsorption isotherm of Cu-bipy-MOF at different temperatures; (e) and (f) adsorption isotherms for C2H2 and C2H4 at 273 K and 293 K for Cu-bipy-MOF. Reproduced with permission from Ref. [102]. Copyright 2018, American Chemical Society.

Fig. 18. (a) The construction of iMOF NKU-112 and self-penetrated MOF NKU-113; (b) N2 isotherms of NKU-112 and NKU-113 at 77 K; (c) C3H8 and C2H6 isotherms of NKU113 at 273 K and 298 K; (d) N2, CH4 and CO2 isotherms of NKU-113 at 273 K. Reproduced with permission from Ref. [103]. Copyright 2018, The Royal Society of Chemistry.

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Fig. 19. (a) Double interpenetrated 3D- networks; (b) water vapor sorption curves for Cd-MOF, Zn-MOF and Co-MOF; (c–e) UV–vis spectra for the uptake of methylene blue from aqueous solutions at various time intervals for Cd-MOF, Zn-MOF and Co-MOF, respectively; (f, g) CO2 sorption at 273 K and 298 K, respectively; (h) N2 sorption at 77 K; (i) CH4 sorption at 298 K. Reproduced with permission from Ref. [79]. Copyright 2017, American Chemical Society.

When Cl
was added to the CH3CN solution of [3BF4@Pd4L148]5+, interpenetrated cage [2Cl + BF4@Pd4L148]5+ was formed, with two
BF
4 guests replaced by Cl in outer pockets. When AgBF4 is added, the interpenetrated cage [2Cl + BF4@Pd4L148]5+ can be transformed into the original interpenetrated cage [3BF4@Pd4L1481]5+. In addition, a complete transformation from interpenetrated cage [3BF4@Pd4L148]5+ to monomeric cage [Pd2L144]4+ can be discovered in DMSO within a week. While the ligand reacts with Pd(NO3)2 in DMSO, the monomeric cage [Pd2L144]4+ was firstly formed (Fig. 10b). Interestingly, the monomeric cage [Pd2L144]4+ can be converted into interpenetrated cage [3NO3@Pd4L148]5+ after heating at 70 °C for one day. Upon addition of TBAC, the interpenetrated cage [3NO3@Pd4L148]5+ can be converted to the interpenetrated cage [2Cl + NO3@Pd4L148]5+, and vice versa by adding AgNO3. In summary, much attention of supramolecular cages has been attracted since the first 3D monomeric cage reported by the Fujita group [48]. The first interlocked supramolecule has led to research hotspots on the structure and properties of interpenetrated double cages. Based on the research about the first iSC reported by Sekiya and Kuroda, the Clever group conducted a series of studies on interpenetrated double cages including their synthesis, structures and properties. It was found that different interpenetrated double cages could be constructed from different ligands. These interpenetrated double cages can adsorb not only halogen anions but also

small neutral molecules. The authors also studied the anion selectivity of interpenetrated double cages and the interaction between interpenetrated double cages and DNA. Furthermore, some other groups have reported that monomeric cages and dimeric cages can be transformed into each other under different circumstances.

3. Interpenetrated metal organic frameworks Metal organic frameworks (MOFs) are frameworks with a periodic network structure that are self-assembled from organic ligands and metal ions. They are also known as metal organic coordination polymers (MOCPs), porous coordination polymers (PCPs) or inorganic organic hybrid materials [70]. MOFs, due to their high porosities, large surface areas, tunable pore sizes and structural diversity, have attracted research targeting many potential applications, such as catalysis [71–74], gas storage [75] and separation [76,77], sensing [78], drug delivery [79] and energy conversion [80,81]. Structural interpenetration is of great interest because it can not only effectively regulate the pore construction of MOFs but also improve the stability of the frameworks by filling the void space [82]. Nevertheless, porous interpenetrated MOFs have been rarely reported in comparison with the large number of porous noninterpenetrated MOFs [83–86].

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Fig. 20. (a) Non-interpenetrated Ru-MOF nRu-MOF; (b) 2-fold interpenetrated iRu-MOF; (c) and (d) the amounts of HCOO
produced from CO2 catalyzed by Ru-MOF nRuMOF and iRu-MOF over time. Reproduced with permission from Ref. [113]. Copyright 2015, American Chemical Society.

In 2007, the Kitagawa group showed the advantages of interpenetrated 3D networks, which can improve the selectivity and strengthen of ions/gases binding because of dynamic changes in the pore size [87]. They constructed a MOF with a 3D interpenetrated topology, which showed a permanent porosity, a high thermal stability, a highly selective sorption, as well as highly selective anion exchange properties (Fig. 11). The pores were initially filled with water. In contrast with O2 or N2, water was selectively replaced by CO2 due to the strong electrostatic interaction. The exchange of excess dicyanamide guests for anions leads to the interconversion of the two interlocked structures, which shows that the anion exchange controls the function of the whole framework. Therefore, a new porous material consisting of two simple building blocks could be employed in gas separation, sensor and anion exchange. This study showed that iMOFs could be triggered by stimuli to selectively absorb guest molecules. In the same year, Chen and co-workers reported a triply interpenetrated microporous MOF for the selective uptake of gas molecules [88]. Up to date, the case of triply iMOF was rather rare. In 2012, incomplete interpenetration in MOFs has been demonstrated, revealing novel properties [89]. Schröder and colleagues showed the interlocking of two frameworks formed from the organic ligands L15 with InIII as metal nodes (Fig. 12). One of the networks is only partially interpenetrated by the second frame, which produces structural defect spots. Due to the incomplete assembly, it can be seen that unconventional gradual filling with CO2 occurs in the pores at low temperatures and pressures during

the adsorption/desorption process. In this case, this kind of MOF could not only capture a variety of gases under high pressure but also selectively capture CO2 in the nanopores under low pressure. The stabilization and tunable porosity of the interwoven MOFs could stimulate an increasing variety of novel porous MOFs for gas adsorption. Zou and his co-workers reported three iMOFs named SUMOF-n (SU = Stockholm University; n = 2, 3, 4) (Fig. 13a) [25]. SUMOF-2 had a structure similar to the interpenetrated MOF-5 [90], SUMOF-3 was an interpenetrated version of IRMOF-8 [91] while SUMOF-4 was crystallized with mixed linkers (Fig. 13b). Among them, SUMOF-4 had the largest specific surface area and pore volume. The uptake of CO2 at relatively low pressures was investigated and the CO2 absorption at 273 K was 4.26, 3.44, and 3.60 mmol g
1, respectively (Fig. 13c). It is found that the uptake of CO2 for SUMOF-2 was remarkably higher than that of noninterpenetrated MOF-5. The interpenetration in SUMOFs can increase the electric field gradients in the small pores, which can enhance the interaction between CO2 and the host framework to increase the uptake of CO2 for SUMOFs. The absorption of CO2 exhibits an almost linear dependence, especially for SUMOF-2, which may be beneficial for separating CO2 from biogas or natural gas by changing the pressure. In 2013, Luo and colleagues reported the first photoactive MOF named ECUT-30 composed of both azobenzene and diarylethene ligands, which can be used to modulate adsorption selectivity of C2H2/CO2 via light [92]. The 3D framework of ECUT-30 is shown

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Fig. 21. (a) The structure of H4BINDI ligand; crystal structures for (b) Mg-NDI (3D structure), (c) Ca-NDI and (d) Sr-NDI (2-fold interpenetrated structure); (e) color changes of MOF materials under sunlight irradiation; (f) preparation of Mg-NDI coated paper; (g) the flexibility of Mg-NDI coated paper; (h) scheme for printing on the coated paper with stencil and sunlight; (i) the content printed on coated paper; (j, k and l) photograph of a content printed on Mg-NDI, Ca-NDI and Sr-NDI coated paper, respectively (top left), content after 12 h of printing (upper right), automatic elimination after 12 h in the dark (bottom left), photograph of the paper after printing for 4th round (bottom right). Reproduced with permission from ref.[114]. Copyright 2016, The Royal Society of Chemistry.

in Fig. 14a and a 4-fold interpenetration is observed (Fig. 14b). In order to prove the robust porosity of ECUT-30, gas adsorption experiments were performed. The permanent porosity can be alternatively confirmed by CO2 adsorption at 195 K. A type I sorption with a CO2 uptake of 97.8 cm3/g
1 at P/P0 = 1 is observed (Fig. 14c). The adsorption of C2H2, C2H4 and CO2 for ECUT-30 was explored (Fig. 14d). It is clearly manifested that ECUT-30 has considerable adsorption capacity for CO2, C2H2 and C2H4. Furthermore, adsorption selectivity is also investigated by the Ideal Adsorbed Solution Theory (IAST) [93]. The adsorption selectivity of ECUT30 under UV irradiation is calculated by IAST (Fig. 14e–g). Obvi-

ously, the absorptivity changed, for example, C2H2/CO2 increased by 57%, C2H4/CO2 decreased by 43.5%, and C2H2/C2H4 increased by 108%. The ECUT-30 displays different photoresponses for different guest molecules, leading to a superior application in adjusting the adsorption selectivity by light. In 2014, Guo and colleagues constructed a photochromic MOF (DMOF), which revealed the high CO2 adsorption capability after UV irradiation [94]. The ZnII is in four-coordinated environment and two ligands are each linked to two ZnII ions. The connectivity generates a four-connected dia net with five-fold interpenetration (Fig. 15a). Under UV irradiation, the single crystal of DMOF pre-

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Fig. 22. (a) The two-fold interpenetrated 3D network; (b) view of the 2D layer in Co/Ni-MOF; (c) view of the 3D network of Co/Ni-MOF; (d) UV–Vis absorption spectra of Bismarck brown during CWAO process in the presence of Co/Ni-MOF; (e) decolorization efficiency of Bismarck brown in the presence of Co/Ni-MOF; (f) UV–Vis absorption spectra and (g) decolorization efficiency of Bismarck brown during CWAO process using pure oxygen in the presence of Co/Ni-MOF; (h) UV–Vis spectra of Bismarck brown solution in the presence of recovered Co/Ni-MOF; (i) the reusability of compound Co/Ni-MOF in the reaction. Reproduced with permission from Ref. [27]. Copyright 2015, Elsevier B.V.

Fig. 23. (a) Octahedral coordination environment around the FeII center in MOF-1; (b) 3D interpenetrated MOF-1. Reproduced with permission from Ref. [115]. Copyright 2017, Wiley-VCH.

sented an obvious color change from yellow to dark blue and could return to its original color after the irradiation of visible light (Fig. 15b). In 2018, Biradha and co-workers reported an interpenetrated CuII-MOF named Cu-MOPF, which displayed a good thermal stability (Fig. 16a) [95]. The permanent porosity was tested and the BET

specific surface area of the material is 2091 m2 g
1 (Fig. 16b). CuMOPF manifested microporous properties and could absorb a large amount of H2 and CO2 but does not absorb CH4. At 77 K and 1 bar, Cu-MOPF showed a hydrogen absorption capacity of 313 cm3 g
1 (Fig. 16c). Compared to several recently reported porous materials, such as Cu-based MOFs TMOF-1 [96], NOTT-103 [84], JUC-1000

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Fig. 24. (a) The scheme of self-assembly of THF-functionalized COF; (b) schematic view of 1-fold and 5-fold interpenetrated frameworks, color code: C, gray; O, red; N, blue; H, white; and Si, orange. The five frameworks are displayed in green, purple, blue, yellow, and red. Reproduced with permission from Ref. [30]. Copyright 2012, American Chemical Society.

[97] and Cu-NTTA [98], Cu-MOPF has the highest H2 absorption ability. In addition, Cu-MOPF has a high adsorption capacity for H2 at low pressure. Under the same conditions, adsorption studies were carried out on Cu-MOPF. The results showed that Cu-MOPF is more inclined to adsorb CO2 than CH4 (Fig. 16d). Furthermore, the Cu-MOPF has high turnover number and turnover frequency values, which results in its excellent recyclability. Beside molecule adsorption abovementioned, iMOFs can also be applied in some other areas such as gas separation [99–101]. Maji and colleagues reported two novel MOFs [102], one is 2D cage-like MOF (Cu-bpp-MOF) and the other is 3D iMOF (Cu-bipy-MOF) (Fig. 17a). Cu-bpp-MOF can adsorb CO2 and the adsorption capacity is 35 mL g
1 at 195 K (Fig. 17b). Compared to Cu-bpp-MOF, the iMOF (Cu-bipy-MOF) displays a higher CO2 absorption ability (Fig. 17c and d). At 273 K and 293 K, Cu-bipy-MOF presents different adsorption ability for C2H2 and C2H4 (Fig. 16e and f, respectively). Due to these results, the iMOF is a promising adsorbent material. Moreover, the compound Cu-bipy-MOF can be utilized as the ideal material for C2H2-C2H4 separation due to the huge adsorption difference. The practical application of most MOFs is limited by their low thermal/acid-base stability, while the interpenetration of MOFs can effectively improve such a stability. Herein, Bu and coworkers constructed iMOF NKU-112 and self-penetrated MOF NKU-113 (Fig. 18a) [103]. The iMOF NKU-112 can be transformed into self-penetrated MOF NKU-113. The transformation between interpenetrated and self-penetrated MOFs has been studied in the past [104,105]. Compared to the former research, the interpenetration extent of the latter’s framework has increased significantly. Although MOF NKU-113 and NKU-112 have a similar framework structure, NKU-113 reveals enhanced porosity and stability compared with NKU-112. The interpenetration of the skeleton in the MOF not only enhances the stability but also adjusts the pore size, thereby enhancing their gas adsorption properties.

Gas adsorption experiments were carried out to test their porosity and gas adsorption properties. The porosity of the material was examined by N2 adsorption test (Fig. 18b) and the BET surface area and Langmuir surface area were 1486 m2 g
1 and 1966 m2 g
1, respectively. For NKU-113, it has a good adsorption capacity for many gases due to its highly porous framework (Fig. 18c and d). The large amount of absorption and adsorption heat of alkanes and CO2 by NKU-112 and NKU-113 indicate their potential application in gas storage and separation. Three iMOFs were reported by Kumar and co-workers, which were named Cd(II) MOF (Cd-MOF), Zn(II) MOF (Zn-MOF) and Co (II) MOF (Co-MOF), respectively [106]. All of the three MOFs are isostructural and contain doubly interpenetrated 3D-networks (Fig. 19a). Among them, Cd(II) MOF and Zn(II) MOF exhibit excellent luminescence properties because of the presence of p-p stacking interactions between the networks. Water vapor adsorption experiments showed that these three MOFs have excellent water vapor adsorption capacity (Fig. 19b). Dye adsorption studies were performed by immersing these three MOFs in an aqueous methylene blue (MB) solution. Due to their porosities, high surface areas and active sites [107–109], they can adsorb pollutants well. UV–Vis spectroscopy showed that the concentration of MB in aqueous solution gradually decreased with time, indicating the adsorption of MB by the MOFs (Fig. 19c–e). Furthermore, adsorption experiments were performed on these three MOFs, indicating that CO2 and N2 can be adsorbed (Fig. 19f–i). Compared with the previously reported MOFs, these three iMOFs manifest significant advantages. In summary, these iMOFs present good water vapor adsorption capacity, selective adsorption of CO2, and ability to remove pollutants from water. MOFs demonstrate diverse applications such as removing dye wastewater and adsorbing gas molecules as introduced in the above. Herein, Luo and colleagues reported two MOFs, which can be used as photocatalysts for CO2 photoreduction because of their

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structural amenability [110–112]. One MOF is non-interpenetrated (nRu-MOF) and the other is 2-fold interpenetrated (iRu-MOF) (Fig. 20) [113]. To evaluate the potential of nRu-MOF and iRuMOF in photocatalytic applications, they used the samples as heterogeneous photocatalyst along with the sacrificial agent, triethanolamine (TEOA), under 420–800 nm light irradiation. During the reaction, the amounts of photocatalytic product (HCOO
) with the increase of irradiation time were shown in Fig. 20c. Within 6 h, nRu-MOF and iRu-MOF showed the same photocatalytic activity. iRu-MOF maintained its photocatalytic activity in the second 6 h of reaction time. However, nRu-MOF gradually became inactive after the first 6 h (Fig. 20d). Consequently, compared to noninterpenetrated Ru-MOF, the interpenetrated Ru-MOF has better stability and more excellent photocatalytic activity. In addition to the abovementioned MOFs for adsorption of CO2 and photocatalysts, the following MOFs can also be used for erasable and ink-free printing due to their interesting reversible color variation properties. Banerjee and co-workers reported three different MOFs, which were synthesized by the solvothermal reactions using the organic BINDI linker (Fig. 21a) and the corresponding metal salts [114]. NDI (1,4,5,8-naphthalenediinide) possesses a redox active core that can conduct a reversible photochromism under proper conditions. The three MOFs display different 3D topologies, in which ligands coordinates with different metal ions (Fig. 21b, c and d). The color of these MOFs depends on their own structures; Mg-NDI is light yellow while the other

two are colorless. When these MOFs were exposed to intense sunlight for 60 s, all of them exhibited dramatic color changes, indicating their photochromic properties (Fig. 21e). The MOF coated paper prepared from Mg-NDI is flexible (Fig. 21f and g) and the printed contents are adjustable attributed to the control of the incidence of sunlight (Fig. 21h). There is no overlap in the printed content, and the color contrast between the front and background is sufficient for comfortable reading (Fig. 21i). Interpenetrated MOFs Caand Sr-NDI, which are formed from the p-p stacking between neighbored NDI units, are different from Mg-NDI, in which printed contents are dark green and give excellent legibility (Fig. 21k and l). The printed content disappears automatically after 24 h (Fig. 21j–l). This property can enable printing on the same paper multiple times, reducing cost and protecting environment. In addition, utilizing different MOFs with different structures, the color of printed content can be changed to meet different requirements. There are many dyes that are toxic and carcinogenic, many methods have been prepared to remove these dyes from sewage. MOFs are reported as catalysts that could effectively improve the dyes removal from wastewater. Alireza and co-workers synthesized a novel interpenetrated mixed Co/Ni-MOF (Fig. 22a) through hydrothermal process [27]. Fig. 22b shows an infinite 2D layer of Co/Ni-MOF formed by tp ligands (tp = terephthalic acid) and mixture solution of Co2+ and Ni2+. These 2D layers containing rectangular grids are pillared by pyrazine ligands to form a 3D network of Co/Ni-MOF shown in Fig. 22c. Authors chose a representative of

Fig. 25. (a) The synthesis of PI-COFs; 3D structures based on non-interpenetrated (b) and interpenetrated (c) diamond nets; (d) UV–VIS spectra of ibuprofen (IBU); (e) release profile of IBU-loaded 3D PI-COFs. Reproduced with permission from Ref. [120]. Copyright 2015, American Chemical Society.

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Fig. 26. (a) Schematic view of 3D-ionic-COF-1 and 3D-ionic-COF-2; (b) structural representations of 3D-ionic-COF: 3-fold interpenetrated diamond topology; (c) N2 adsorption and CO2 uptake for 3D-ionic-COF-1 and 3D-ionic-COF-2. Reproduced with permission from Ref. [29]. Copyright 2017, American Chemical Society.

the contaminants in the water named Bismarck brown and used this interspersed MOF as catalysts for the reaction to test the removal efficiency of this contaminant. UV–Vis spectra of the dye solution (Fig. 22d) and decolorization efficiency of Bismarck brown (Fig. 22e) showed that the compound Co/Ni-MOF can act as the active catalyst in the catalytic wet air oxidation (CWAO) of the dye. In addition, the authors conducted a controlled experiment to determine the effect of oxygen on the color removal of Bismarck brown. The results showed that in pure oxygen, the degradation efficiency of the fuel is higher than that without pure oxygen (Fig. 22f and g). Finally, they investigated whether compound Co/ Ni-MOF can be recycled or not. It was found that the recovered catalyst maintained its activity in the CWAO of the dye without significant loss of decolorization efficiency (Fig. 22h and i). Compound Co/Ni-MOF can be recycled at least 3 cycles and denotes a good stability in the catalytic process. Inspired by the potential to obtain novel multifunctional materials with redox-switchable and multi-stimuli responsive properties, Zuo and co-workers rationally constructed a 3D MOF-1 by introducing the redox active ligand tetra(4-pyridyl) tetrathiafulvalene (TTF-(py)4) and spin-crossover FeII centers (Fig. 23) [115]. MOF-1 exhibited magnetic, electronic, and optical properties, which could be used in the potential multifunction of molecular electronics devices. In recent years, chemists have synthesized and designed various iMOFs. The iMOFs usually display better stability than the non-interpenetrated MOFs, which makes their practical applications possible. Interpenetration in MOFs not only forms an interesting structure, but also manifests fascinating properties and applications. 4. Interpenetrated covalent organic frameworks Covalent organic frameworks (COFs) are a new class of porous crystalline materials constructed from purely organic building blocks. COFs are linked by reversible covalent bonds, forming

highly ordered and predesignable 2D or 3D architectures. COFs are commonly constituted from light elements (B, C, N, O, Si) and demonstrate how crystalline architectures of covalent solids can be achieved [116]. Due to the covalent periodic ordering linkage as well as the elaborate control of the organic units, including their geometry, size, and functionality, COFs have emerged as tailormade porous materials and exhibit great potential in a variety of applications such as gas storage and separation [117], optoelectronics [118], and catalysis [119], etc. Since Yaghi manifested the pioneering work of COFs in 2005 [14], the design and synthesis of 2D COFs have been well established through several condensation reactions. The exploration of 3D COFs is still considered to be a great challenge since the availability of specific 3D COFs is limited. Babarao and co-workers prepared several interlocked and THF-functionalized COFs with diamondoid topologies [30]. In their study, the THFfunctionalized COF was self-assembled via a reversible imine condensation reaction from tetrakisaldehydes and diamines as tetrahedral nodes and ditopic links, respectively (Fig. 24a). Adjacent nodes rotated around S4 axes, leading to conrotatory frameworks and four series of structures, with iCOFs consisting of 1-fold to 5fold frameworks. The 1-fold and 5-fold iCOFs with disrotatory nodes and diaxial linkers are depicted in Fig. 24b. Experiment results showed that interpenetration in COFs could increase the absorption of CO2 under low pressure and CO2 selectivity over other gases was also enhanced due to the sieving effect. In 2015, the first example of COFs used in drug delivery was reported by Fang and co-workers [120]. Two novel 3D COFs, PICOF-4 and PI-COF-5, with high thermal stability and surface area were obtained (Fig. 25a). One is non-interpenetrated and the other is interpenetrated structure (Fig. 25b and c), which can be synthesized by selecting tetrahedron construction units of distinct sizes. The authors carried out drug loading experiments on the obtained COFs, and the results revealed their good drug delivery capability (Fig. 25d and e). Furthermore, iCOF PI-COF-5 shows a slower release rate compared to the non-interpenetrated PI-COF-4.

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Fig. 27. (a) Synthesis of 3D-OH-COF and 3D-COOH-COF (TFPM, tetra(4-formylphenyl)methane; DHBD, 3,30 -dihydroxybenzidine); (b-c) N2 adsorption-desorption isotherms for 3D-OH-COF (b) and 3D-COOH-COF (c) at 77 K; (d) metal ion adsorption isotherms of 3D-COOH-COF at room temperature; (e) IAST selectivity of 3D-COOH-COF for lanthanide ions mixtures. Reproduced with permission from Ref. [121]. Copyright 2018, Wiley-VCH.

In 2017, Fang and co-workers reported a general strategy for designing positively charged porous 3D ionic COFs by incorporating cationic monomers in the framework [29]. The 3D-ionic-COF1 and 3D-ionic-COF-2 (Fig. 26a) feature 3-fold interpenetrated structures with diamond topologies (Fig. 26b). Furthermore, these 3D-ionic-COFs show high specific surface areas, remarkable CO2 uptakes and N2 adsorption capacities (Fig. 26c). The 3D-ionicCOFs successfully prepared in their work may not only expand the development of COFs with extraordinary structures but also promote the applications of COFs as efficient functional materials. In the same group, they introduced different groups, hydroxyl and carboxyl, into COFs to provide COFs reactive functions (Fig. 27a) [121]. The two COFs are multi-interpenetrated network due to the particular pattern the reactants connected [122]. The COFs exhibited high crystallinity and thermal stability. The N2 adsorption and desorption experiments of COF showed that both COFs have high specific surface area (Fig. 27b and c). Furthermore, 3D-COOH-COF can effectively extract lanthanide ions from aqueous solution (Fig. 27d) and exhibits a high selectivity for Nd3+ over Sr2+ and Fe3+ (Fig. 27e). This performance can effectively treat radioactive contaminants, which opens up applications in the area of environmental protection. In 2018, the Fang group constructed a series of 3D COFs with multi-fold interpenetrated diamondoid (dia) nets, termed 3D-IL-

COF-n (n = 1, 2, 3) (Fig. 28a) [123]. Authors used ionic liquid (IL) as solvent to carry out the reaction at ambient temperature and atmospheric pressure. The method is simple and environmentally friendly, and can quickly obtain 3D COFs. In Fig. 28b, the 3D-ILCOFs rapidly adsorb gas at low pressure, exhibiting their microporous properties. A series of experiments have shown that 3D-ILCOFs can efficiently separate CO2 gas from N2 and CH4 (Fig. 28c– e). Mixed gases (N2, CH4, CO2) were flowed through the iCOF, and only CO2 remained in the pores of the 3D-IL-COFs (Fig. 28f and g). The results confirmed that this type of iCOFs can selectively adsorb CO2 from CO2/N2 and CO2/CH4. In recent years, chemists have performed a lot of research on the structural design, synthesis and properties of COFs. Compared with non-interpenetrated COFs, the interpenetration of COFs can reduce the pore size and stabilize the frameworks, which leads to a higher permanent porosity. Deeper investigation of iCOFs is ongoing in several groups all over the world. 5. Conclusion and outlook In summary, many interpenetrated structures have been reported and much attention has been attracted due to their interesting synthetic design, fascinating topologies and potential applications. It is clear that interpenetrated architectures are more

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Fig. 28. (a) The synthesis of 3D-IL-COF-n (n = 1, 2, 3); (b) N2 adsorption-desorption isotherms for 3D-IL-COF-n; CO2 separation properties for isoreticular (c) 3D-IL-COF-1, (d) 3D-IL-COF-2 and (e) 3D-IL-COF-3; breakthrough curves for 3D-ILCOF-1 using (f) CO2/N2 and (g) CO2/CH4 gas mixture. Reproduced with permission from Ref. [123]. Copyright 2018, American Chemical Society.

thermodynamically stable than the corresponding monomeric structures. Furthermore, mutually penetrated structures manifested improved properties and extended applications compared to the corresponding monomeric structures owing to the strengthened interaction between the cavities of the architectures and the captured guests. As we discussed in the above, iSCs display more densely packed aggregates than monomeric cages, resulting in enhanced thermal stability and improved selectivity; iMOFs manifest expanded applications in gas adsorption and selectively catalysis due to the abundance of pore surfaces and limited flexibility of the frameworks; iCOFs exhibit advanced ability in the applications of drug delivery and recognition of radioactive contaminants compared with non-interpenetrated COFs. Although interpenetrated structures were discovered by chance, due to their potential applications from multifunctionalization, they have attracted much attention from chemists. Many factors may affect the process of interpenetration, such as the topology of ligand, the size of the guest and the reaction condition et al. As a result, the self-assembly of interpenetrated architectures remains unpredictable and the characterization methods remains limited. Further research is needed to understand the factors that influence the interpenetration process. Theoretical calculations are needed to assist the experiment in the prediction of the interpenetrated structures formation. The length, bending degree and stability of ligands should be calculated and analyzed first to increase the possibility of interpenetration and predict the corresponding designation. Advanced techniques are required to monitor the process of interpenetration

and characterize such complex compositions, such as synchrotron X-ray diffraction, X-ray absorption near edge structure, Rutherford backscattering spectrometry and in-situ scanning electron microscopy. A particular concern for chemists is to reveal the mechanism of the interpenetration process and the enhanced properties of interpenetrated structures compared with the noninterpenetrated one. Additionally, further exploration of the relationship between the structures and their improved applications is urgent. There are many strategies for synthesizing interpenetrated species, but most researches only focus on their structures and properties. The next step should functionalize the species of the interpenetrated structures and realize their practical applications in industry. We hope that more properties and functions of such a particular architecture will be investigated and can be applied in various fields. Acknowledgements This work was supported by the National Natural Science Foundation of China (NSFC-21671170, 21673203, and 21201010), the Top-notch Academic Programs Project of Jiangsu Higher Education Institutions(TAPP), Program for New Century Excellent Talents of the University in China (NCET-13-0645), the Science & Technology Foundation of Jiangsu Province (Grant No. BK20150438), the Six Talent Plan (Grant No. 2015-XCL-030), and Lvyangjinfeng Talent Program of Yangzhou. We also acknowledge the Priority Academic Program Development of Jiangsu Higher Education Institutions.

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Appendix A. Supplementary data Supplementary data to this article can be found online at https://doi.org/10.1016/j.ccr.2019.03.002. References [1] T. Kusukawa, M. Fujita, Self-assembled M6L4-type coordination nanocage with 2,20 -bipyridine ancillary ligands. Facile crystallization and X-ray analysis of shape-selective enclathration of neutral guests in the cage, J. Am. Chem. Soc. 124 (2002) 13576–13582, https://doi.org/10.1021/ja020712k. [2] M. Yoshizawa, M. Tamura, M. Fujita, AND/OR bimolecular recognition, J. Am. Chem. Soc. 126 (2004) 6846–6847, https://doi.org/10.1021/ja048860t. [3] Y. Nishioka, T. Yamaguchi, M. Kawano, M. Fujita, Asymmetric [2+2] olefin cross photoaddition in a self-assembled host with remote chiral auxiliaries, J. Am. Chem. Soc. 130 (2008) 8160–8161, https://doi.org/10.1021/ja802818t. [4] K. Nakabayashi, M. Kawano, M. Fujita, pH-switchable through-space interaction of organic radicals within a self-assembled coordination cage, Angew. Chem. Int. Ed. 44 (2005) 5322–5325, https://doi.org/10.1002/ anie.200501568. [5] X.-J. Li, F.-L. Jiang, M.-Y. Wu, S.-Q. Zhang, Y.-F. Zhou, M.-C. Hong, Selfassembly of discrete M6L8 coordination cages based on a conformationally flexible tripodal phosphoric triamide ligand, Inorg. Chem. 51 (2012) 4116– 4122, https://doi.org/10.1021/ic202373a. [6] W.M. Bloch, G.H. Clever, Integrative self-sorting of coordination cages based on ‘naked’ metal ions, Chem. Commun. 53 (2017) 8506–8516, https://doi.org/ 10.1039/C7CC03379F. [7] M. Han, D.M. Engelhard, G.H. Clever, Self-assembled coordination cages based on banana-shaped ligands, Chem. Soc. Rev. 43 (2014) 1848–1860, https://doi. org/10.1039/C3CS60473J. [8] L.J. Murray, M. Dinca˘, J.R. Long, Hydrogen storage in metal-organic frameworks, Chem. Soc. Rev. 38 (2009) 1294, https://doi.org/10.1039/b802256a. [9] R.J. Kuppler, D.J. Timmons, Q.-R. Fang, J.-R. Li, T.A. Makal, M.D. Young, D. Yuan, D. Zhao, W. Zhuang, H.-C. Zhou, Potential applications of metal-organic frameworks, Coord. Chem. Rev. 253 (2009) 3042–3066, https://doi.org/ 10.1016/j.ccr.2009.05.019. [10] L. Liu, Y. Zhou, S. Liu, M. Xu, The applications of metal-organic frameworks in electrochemical sensors, ChemElectroChem 5 (2018) 6–19, https://doi.org/ 10.1002/celc.201700931. [11] Y.-H. Zhu, X. Yang, D. Bao, X.-F. Bie, T. Sun, S. Wang, Y.-S. Jiang, X.-B. Zhang, J.M. Yan, Q. Jiang, High-energy-density flexible potassium-ion battery based on patterned electrodes, Joule 2 (2018) 736–746, https://doi.org/10.1016/j. joule.2018.01.010. [12] Y. Zhu, Y. Yin, X. Yang, T. Sun, S. Wang, Y. Jiang, J. Yan, X. Zhang, Transformation of rusty stainless-steel meshes into stable, low-cost, and binder-free cathodes for high-performance potassium-ion batteries, Angew. Chem. Int. Ed. 56 (2017) 7881–7885, https://doi.org/10.1002/ anie.201702711. [13] F. Meng, H. Zhong, D. Bao, J. Yan, X. Zhang, In situ coupling of strung Co4N and intertwined N-C fibers toward free-standing bifunctional cathode for robust, efficient, and flexible Zn-Air batteries, J. Am. Chem. Soc. 138 (2016) 10226– 10231, https://doi.org/10.1021/jacs.6b05046. [14] A.P. Cote, Porous, crystalline, covalent organic frameworks, Science 310 (2005) 1166–1170, https://doi.org/10.1126/science.1120411. [15] A.M. Khattak, Z.A. Ghazi, B. Liang, N.A. Khan, A. Iqbal, L. Li, Z. Tang, A redoxactive 2D covalent organic framework with pyridine moieties capable of faradaic energy storage, J. Mater. Chem. A 4 (2016) 16312–16317, https://doi. org/10.1039/C6TA05784E. [16] J.W. Colson, A.R. Woll, A. Mukherjee, M.P. Levendorf, E.L. Spitler, V.B. Shields, M.G. Spencer, J. Park, W.R. Dichtel, Oriented 2D covalent organic framework thin films on single-layer graphene, Science 332 (2011) 228–231, https://doi. org/10.1126/science.1202747. [17] E. Jin, M. Asada, Q. Xu, S. Dalapati, M.A. Addicoat, M.A. Brady, H. Xu, T. Nakamura, T. Heine, Q. Chen, D. Jiang, Two-dimensional sp2 carbonconjugated covalent organic frameworks, Science 357 (2017) 673–676, https://doi.org/10.1126/science.aan0202. [18] S. Pullen, G.H. Clever, Mixed-ligand metal-organic frameworks and heteroleptic coordination cages as multifunctional scaffolds-A comparison, Acc. Chem. Res. 51 (2018) 3052–3064, https://doi.org/10.1021/acs. accounts.8b00415. [19] T.R. Cook, Y.-R. Zheng, P.J. Stang, Metal-organic frameworks and selfassembled supramolecular coordination complexes: comparing and contrasting the design, synthesis, and functionality of metal-organic materials, Chem. Rev. 113 (2013) 734–777, https://doi.org/10.1021/ cr3002824. [20] J.L. Turner, K.L. Wooley, Nanoscale cage-like structures derived from polyisoprene-containing shell cross-linked nanoparticle templates, Nano Lett. 4 (2004) 683–688, https://doi.org/10.1021/nl0497981. [21] K. Ono, M. Yoshizawa, M. Akita, T. Kato, Y. Tsunobuchi, S. Ohkoshi, M. Fujita, Spin crossover by encapsulation, J. Am. Chem. Soc. 131 (2009) 2782–2783, https://doi.org/10.1021/ja8089894. [22] T. Murase, S. Horiuchi, M. Fujita, Naphthalene Diels-Alder in a self-assembled molecular flask, J. Am. Chem. Soc. 132 (2010) 2866–2867, https://doi.org/ 10.1021/ja9107275.

[23] D.F. Sava, V.C. Kravtsov, J. Eckert, J.F. Eubank, F. Nouar, M. Eddaoudi, Exceptional stability and high hydrogen uptake in hydrogen-bonded metalorganic cubes possessing ACO and AST zeolite-like topologies, J. Am. Chem. Soc. 131 (2009) 10394–10396, https://doi.org/10.1021/ja903287v. [24] Y.-B. Dong, P. Wang, J.-P. Ma, X.-X. Zhao, H.-Y. Wang, B. Tang, R.-Q. Huang, Coordination-driven nanosized lanthanide ‘‘molecular lantern” with tunable luminescent properties, J. Am. Chem. Soc. 129 (2007) 4872–4873, https://doi. org/10.1021/ja070058e. [25] Q. Yao, J. Su, O. Cheung, Q. Liu, N. Hedin, X. Zou, Interpenetrated metalorganic frameworks and their uptake of CO2 at relatively low pressures, J. Mater. Chem. 22 (2012) 10345, https://doi.org/10.1039/c2jm15933c. [26] S. Bureekaew, H. Sato, R. Matsuda, Y. Kubota, R. Hirose, J. Kim, K. Kato, M. Takata, S. Kitagawa, Control of interpenetration for tuning structural flexibility influences sorption properties, Angew. Chem. Int. Ed. 122 (2010) 7826–7830, https://doi.org/10.1002/ange.201002259. [27] A. Abbasi, M. Soleimani, M. Najafi, S. Geranmayeh, New interpenetrated mixed (Co/Ni) metal-organic framework for dye removal under mild conditions, Inorg. Chim. Acta 439 (2016) 18–23, https://doi.org/10.1016/j. ica.2015.09.028. [28] K.B. Sezginel, P.A. Asinger, H. Babaei, C.E. Wilmer, Thermal transport in interpenetrated metal-organic frameworks, Chem. Mater. 30 (2018) 2281– 2286, https://doi.org/10.1021/acs.chemmater.7b05015. [29] Z. Li, H. Li, X. Guan, J. Tang, Y. Yusran, Z. Li, M. Xue, Q. Fang, Y. Yan, V. Valtchev, S. Qiu, Three-dimensional ionic covalent organic frameworks for rapid, reversible, and selective ion exchange, J. Am. Chem. Soc. 139 (2017) 17771– 17774, https://doi.org/10.1021/jacs.7b11283. [30] R. Babarao, R. Custelcean, B.P. Hay, D. Jiang, Computer-aided design of interpenetrated tetrahydrofuran-functionalized 3D covalent organic frameworks for CO2 capture, Cryst. Growth Des. 12 (2012) 5349–5356, https://doi.org/10.1021/cg3009688. [31] M.M.J. Smulders, I.A. Riddell, C. Browne, J.R. Nitschke, Building on architectural principles for three-dimensional metallosupramolecular construction, Chem. Soc. Rev. 42 (2013) 1728–1754, https://doi.org/10.1039/C2CS35254K. [32] R. Chakrabarty, P.S. Mukherjee, P.J. Stang, Supramolecular coordination: selfassembly of finite two- and three-dimensional ensembles, Chem. Rev. 111 (2011) 6810–6918, https://doi.org/10.1021/cr200077m. [33] S.J. Dalgarno, N.P. Power, J.L. Atwood, Metallo-supramolecular capsules, Coord. Chem. Rev. 252 (2008) 825–841, https://doi.org/10.1016/j. ccr.2007.10.010. [34] D.J. Tranchemontagne, Z. Ni, M. O’Keeffe, O.M. Yaghi, Reticular chemistry of metal-organic polyhedra, Angew. Chem. Int. Ed. 47 (2008) 5136–5147, https://doi.org/10.1002/anie.200705008. [35] K. Harris, D. Fujita, M. Fujita, Giant hollow MnL2n spherical complexes: structure, functionalisation and applications, Chem. Commun. 49 (2013) 6703, https://doi.org/10.1039/c3cc43191f. [36] T.R. Cook, P.J. Stang, Recent developments in the preparation and chemistry of metallacycles and metallacages via coordination, Chem. Rev. 115 (2015) 7001–7045, https://doi.org/10.1021/cr5005666. [37] M. Frank, M.D. Johnstone, G.H. Clever, Interpenetrated cage structures, Chem. A Eur. J 22 (2016) 14104–14125, https://doi.org/10.1002/chem.201601752. [38] M. Fujita, N. Fujita, K. Ogura, K. Yamaguchi, Spontaneous assembly of ten components into two interlocked, identical coordination cages, Nature 400 (1999) 52–55, https://doi.org/10.1038/21861. [39] Y. Li, K.M. Mullen, T.D.W. Claridge, P.J. Costa, V. Felix, P.D. Beer, Sulfate anion templated synthesis of a triply interlocked capsule, Chem. Commun. (2009) 7134, https://doi.org/10.1039/b915548a. [40] R. Sekiya, M. Fukuda, R. Kuroda, Anion-directed formation and degradation of an interlocked metallohelicate, J. Am. Chem. Soc. 134 (2012) 10987–10997, https://doi.org/10.1021/ja303634u. [41] M.D. Giles, S. Liu, R.L. Emanuel, B.C. Gibb, S.M. Grayson, Dendronized supramolecular nanocapsules: pH independent, water-soluble, deep-cavity cavitands assemble via the hydrophobic effect, J. Am. Chem. Soc. 130 (2008) 14430–14431, https://doi.org/10.1021/ja806457x. [42] R. Custelcean, J. Bosano, P.V. Bonnesen, V. Kertesz, B.P. Hay, Computer-aided design of a sulfate-encapsulating receptor, Angew. Chemie. 121 (2009) 4085– 4089, https://doi.org/10.1002/ange.200900108. [43] P. Mal, B. Breiner, K. Rissanen, J.R. Nitschke, White phosphorus is air-stable within a self-assembled tetrahedral capsule, Science 324 (2009) 1697–1699, https://doi.org/10.1126/science.1175313. [44] F. Schmitt, J. Freudenreich, N.P.E. Barry, L. Juillerat-Jeanneret, G. Süss-Fink, B. Therrien, Organometallic cages as vehicles for intracellular release of photosensitizers, J. Am. Chem. Soc. 134 (2012) 754–757, https://doi.org/ 10.1021/ja207784t. [45] A. Galan, P. Ballester, Stabilization of reactive species by supramolecular encapsulation, Chem. Soc. Rev. 45 (2016) 1720–1737, https://doi.org/ 10.1039/C5CS00861A. [46] S. Leininger, B. Olenyuk, P.J. Stang, Self-assembly of discrete cyclic nanostructures mediated by transition metals, Chem. Rev. 100 (2000) 853– 908, https://doi.org/10.1021/cr9601324. [47] K. Swaminathan Iyer, M. Norret, S.J. Dalgarno, J.L. Atwood, C.L. Raston, Loading molecular hydrogen cargo within viruslike nanocontainers, Angew. Chem. Int. Ed. 47 (2008) 6362–6366, https://doi.org/10.1002/anie.200802441. [48] T. Kusukawa, M. Fujita, Encapsulation of large, neutral molecules in a selfassembled nanocage incorporating six palladium(II) ions, Angew. Chem. Int. Ed. 37 (1998) 3142–3144, https://doi.org/10.1002/(SICI)1521-3773 (19981204)37:22<3142::AID-ANIE3142>3.0.CO;2-9.

R. Zhu et al. / Coordination Chemistry Reviews 389 (2019) 119–140 [49] M. Fujita, D. Oguro, M. Miyazawa, H. Oka, K. Yamaguchi, K. Ogura, Selfassembly of ten molecules into nanometre-sized organic host frameworks, Nature 378 (1995) 469–471, https://doi.org/10.1038/378469a0. [50] D. Fiedler, D.H. Leung, R.G. Bergman, K.N. Raymond, Selective molecular recognition, C–H bond activation, and catalysis in nanoscale reaction vessels, Acc. Chem. Res. 38 (2005) 349–358, https://doi.org/10.1021/ar040152p. [51] M. Yoshizawa, J.K. Klosterman, M. Fujita, Functional molecular flasks: new properties and reactions within discrete, self-assembled hosts, Angew. Chem. Int. Ed. 48 (2009) 3418–3438, https://doi.org/10.1002/anie.200805340. [52] M. Fukuda, R. Sekiya, R. Kuroda, A quadruply stranded metallohelicate and its spontaneous dimerization into an interlocked metallohelicate, Angew. Chem. Int. Ed. 120 (2008) 718–722, https://doi.org/10.1002/ange.200703162. [53] G.H. Clever, P. Punt, Cation-anion arrangement patterns in self-assembled Pd2L4 and Pd4L8 coordination cages, Acc. Chem. Res. 50 (2017) 2233–2243, https://doi.org/10.1021/acs.accounts.7b00231. [54] S. Freye, J. Hey, A. Torras-Galán, D. Stalke, R. Herbst-Irmer, M. John, G.H. Clever, Allosteric binding of halide anions by a new dimeric interpenetrated coordination cage, Angew. Chem. Int. Ed. 51 (2012) 2191–2194, https://doi. org/10.1002/anie.201107184. [55] S. Freye, D.M. Engelhard, M. John, G.H. Clever, Counterion dynamics in an interpenetrated coordination cage capable of dissolving AgCl, Chem. Eur. J. 19 (2013) 2114–2121, https://doi.org/10.1002/chem.201203086. [56] S. Löffler, J. Lübben, L. Krause, D. Stalke, B. Dittrich, G.H. Clever, Triggered exchange of anionic for neutral guests inside a cationic coordination cage, J. Am. Chem. Soc. 137 (2015) 1060–1063, https://doi.org/10.1021/ja5130379. [57] S. Löffler, A. Wuttke, B. Zhang, J.J. Holstein, R.A. Mata, G.H. Clever, Influence of size, shape, heteroatom content and dispersive contributions on guest binding in a coordination cage, Chem. Commun. 53 (2017) 11933–11936, https://doi.org/10.1039/C7CC04855F. [58] S. Turega, W. Cullen, M. Whitehead, C.A. Hunter, M.D. Ward, Mapping the internal recognition surface of an octanuclear coordination cage using guest libraries, J. Am. Chem. Soc. 136 (2014) 8475–8483, https://doi.org/ 10.1021/ja504269m. [59] M. Frank, J. Hey, I. Balcioglu, Y.-S. Chen, D. Stalke, T. Suenobu, S. Fukuzumi, H. Frauendorf, G.H. Clever, Selbstassemblierung und schrittweise oxidation von Phenothiazin-basierten, interpenetrierten Koordinationskäfigen, Angew. Chem. Int. Ed. 125 (2013) 10288–10293, https://doi.org/10.1002/ ange.201302536. [60] M. Frank, J. Hey, I. Balcioglu, Y.-S. Chen, D. Stalke, T. Suenobu, S. Fukuzumi, H. Frauendorf, G.H. Clever, Assembly and stepwise oxidation of interpenetrated coordination cages based on phenothiazine, Angew. Chem. Int. Ed. 52 (2013) 10102–10106, https://doi.org/10.1002/anie.201302536. [61] M. Frank, J. Ahrens, I. Bejenke, M. Krick, D. Schwarzer, G.H. Clever, Lightinduced charge separation in densely packed donor-acceptor coordination cages, J. Am. Chem. Soc. 138 (2016) 8279–8287, https://doi.org/ 10.1021/jacs.6b04609. [62] R. Zhu, J. Lübben, B. Dittrich, G.H. Clever, Stepwise halide-triggered double and triple catenation of self-assembled coordination cages, Angew. Chem. Int. Ed. 54 (2015) 2796–2800, https://doi.org/10.1002/anie.201408068. [63] R. Zhu, I. Regeni, J.J. Holstein, B. Dittrich, M. Simon, S. Prévost, M. Gradzielski, G.H. Clever, Catenation and aggregation of multi-cavity coordination cages, Angew. Chem. Int. Ed. (2018), https://doi.org/10.1002/anie.201806047. [64] J.J. Henkelis, T.K. Ronson, L.P. Harding, M.J. Hardie, M3L2 metallocryptophanes: [2]catenane and simple cages, Chem. Commun. 47 (2011) 6560, https://doi.org/10.1039/c1cc10806a. [65] M. Fukuda, R. Sekiya, R. Kuroda, A quadruply stranded metallohelicate and its spontaneous dimerization into an interlocked metallohelicate, Angew. Chem. Int. Ed. 47 (2008) 706–710, https://doi.org/10.1002/anie.200703162. [66] R. Sekiya, R. Kuroda, Pd2+  O3SR
interaction encourages anion encapsulation of a quadruply-stranded Pd complex to achieve chirality or high solubility, Chem. Commun. 47 (2011) 12346, https://doi.org/10.1039/c1cc14982b. [67] D. Samanta, P.S. Mukherjee, Sunlight-induced covalent marriage of two triply interlocked Pd6 cages and their facile thermal separation, J. Am. Chem. Soc. 136 (2014) 17006–17009, https://doi.org/10.1021/ja511360e. [68] G.M.J. Schmidt, Photodimerization in the solid state, Pure Appl. Chem. 27 (1971), https://doi.org/10.1351/pac197127040647. [69] Y.-H. Li, J.-J. Jiang, Y.-Z. Fan, Z.-W. Wei, C.-X. Chen, H.-J. Yu, S.-P. Zheng, D. Fenske, C.-Y. Su, M. Barboiu, Solvent- and anion-induced interconversions of metal-organic cages, Chem. Commun. 52 (2016) 8745–8748, https://doi.org/ 10.1039/C6CC04420D. [70] B.F. Hoskins, R. Robson, Infinite polymeric frameworks consisting of three dimensionally linked rod-like segments, J. Am. Chem. Soc. 111 (1989) 5962– 5964, https://doi.org/10.1021/ja00197a079. [71] C.M. McGuirk, M.J. Katz, C.L. Stern, A.A. Sarjeant, J.T. Hupp, O.K. Farha, C.A. Mirkin, Turning on catalysis: incorporation of a hydrogen-bond-donating squaramide moiety into a Zr metal-organic framework, J. Am. Chem. Soc. 137 (2015) 919–925, https://doi.org/10.1021/ja511403t. [72] J.-M. Yan, Z.-L. Wang, L. Gu, S.-J. Li, H.-L. Wang, W.-T. Zheng, Q. Jiang, AuPdMnOx/MOF-graphene: an efficient catalyst for hydrogen production from formic acid at room temperature, Adv. Energy Mater. 5 (2015) 1500107, https://doi.org/10.1002/aenm.201500107. [73] H.-L. Jiang, S.K. Singh, J.-M. Yan, X.-B. Zhang, Q. Xu, Liquid-phase chemical hydrogen storage: catalytic hydrogen generation under ambient conditions, ChemSusChem. 3 (2010) 541–549, https://doi.org/10.1002/cssc.201000023. [74] K.-H. Liu, H.-X. Zhong, S.-J. Li, Y.-X. Duan, M.-M. Shi, X.-B. Zhang, J.-M. Yan, Q. Jiang, Advanced catalysts for sustainable hydrogen generation and storage via

[75]

[76]

[77]

[78]

[79]

[80]

[81]

[82]

[83]

[84]

[85]

[86]

[87]

[88]

[89]

[90]

[91]

[92]

[93]

[94]

[95]

139

hydrogen evolution and carbon dioxide/nitrogen reduction reactions, Prog. Mater. Sci. 92 (2018) 64–111, https://doi.org/10.1016/j.pmatsci.2017.09.001. S.-J. Li, H.-L. Wang, B.-R. Wulan, X. Zhang, J.-M. Yan, Q. Jiang, Complete dehydrogenation of N2H4 BH3 over noble-metal-free Ni0.5Fe0.5-CeOx /MIL-101 with high activity and 100% H2 selectivity, Adv. Energy Mater. 8 (2018) 1800625, https://doi.org/10.1002/aenm.201800625. T. Rodenas, I. Luz, G. Prieto, B. Seoane, H. Miro, A. Corma, F. Kapteijn, F.X. Llabrés i Xamena, J. Gascon, Metal-organic framework nanosheets in polymer composite materials for gas separation, Nat. Mater. 14 (2014) 48–55, https:// doi.org/10.1038/nmat4113. Y. Zhu, S. Yuan, D. Bao, Y. Yin, H. Zhong, X. Zhang, J. Yan, Q. Jiang, Decorating waste cloth via industrial wastewater for tube-type flexible and wearable sodium-ion batteries, Adv. Mater. 29 (2017) 1603719, https://doi.org/ 10.1002/adma.201603719. L.E. Kreno, K. Leong, O.K. Farha, M. Allendorf, R.P. Van Duyne, J.T. Hupp, Metal-organic framework materials as chemical sensors, Chem. Rev. 112 (2012) 1105–1125, https://doi.org/10.1021/cr200324t. P. Horcajada, T. Chalati, C. Serre, B. Gillet, C. Sebrie, T. Baati, J.F. Eubank, D. Heurtaux, P. Clayette, C. Kreuz, J.-S. Chang, Y.K. Hwang, V. Marsaud, P.-N. Bories, L. Cynober, S. Gil, G. Férey, P. Couvreur, R. Gref, Porous metal-organicframework nanoscale carriers as a potential platform for drug delivery and imaging, Nat. Mater. 9 (2010) 172–178, https://doi.org/10.1038/nmat2608. F.-L. Meng, K.-H. Liu, Y. Zhang, M.-M. Shi, X.-B. Zhang, J.-M. Yan, Q. Jiang, Recent advances toward the rational design of efficient bifunctional air electrodes for rechargeable Zn-Air batteries, Small. 14 (2018) 1703843, https://doi.org/10.1002/smll.201703843. H.-X. Zhong, J. Wang, Q. Zhang, F. Meng, D. Bao, T. Liu, X.-Y. Yang, Z.-W. Chang, J.-M. Yan, X.-B. Zhang, In situ coupling FeM (M = Ni, Co) with nitrogen-doped porous carbon toward highly efficient trifunctional electrocatalyst for overall water splitting and rechargeable Zn-Air battery, Adv. Sustain. Syst. 1 (2017) 1700020, https://doi.org/10.1002/adsu.201700020. S.-T. Zheng, J.T. Bu, Y. Li, T. Wu, F. Zuo, P. Feng, X. Bu, Pore space partition and charge separation in cage-within-cage indium-organic frameworks with high CO2 uptake, J. Am. Chem. Soc. 132 (2010) 17062–17064, https://doi.org/ 10.1021/ja106903p. J.K. Schnobrich, K. Koh, K.N. Sura, A.J. Matzger, A framework for predicting surface areas in microporous coordination polymers, Langmuir 26 (2010) 5808–5814, https://doi.org/10.1021/la9037292. X. Lin, I. Telepeni, A.J. Blake, A. Dailly, C.M. Brown, J.M. Simmons, M. Zoppi, G. S. Walker, K.M. Thomas, T.J. Mays, P. Hubberstey, N.R. Champness, M. Schröder, 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. 131 (2009) 2159–2171, https://doi.org/ 10.1021/ja806624j. Y.K. Park, S.B. Choi, H. Kim, K. Kim, B.-H. Won, K. Choi, J.-S. Choi, W.-S. Ahn, N. Won, S. Kim, D.H. Jung, S.-H. Choi, G.-H. Kim, S.-S. Cha, Y.H. Jhon, J.K. Yang, J. Kim, Crystal structure and guest uptake of a mesoporous metal-organic framework containing cages of 3.9 and 4.7 nm in diameter, Angew. Chem. Int. Ed. 119 (2007) 8378–8381, https://doi.org/10.1002/ange.200702324. T.M. Reineke, M. Eddaoudi, D. Moler, M. O’Keeffe, O.M. Yaghi, Large free volume in maximally interpenetrating networks: the role of secondary building units exemplified by Tb2(ADB)3[(CH3)2SO]416[(CH3)2SO]1, J. Am. Chem. Soc. 122 (2000) 4843–4844, https://doi.org/10.1021/ja000363z. T.K. Maji, R. Matsuda, S. Kitagawa, A flexible interpenetrating coordination framework with a bimodal porous functionality, Nat. Mater. 6 (2007) 142– 148, https://doi.org/10.1038/nmat1827. B. Chen, S. Ma, E.J. Hurtado, E.B. Lobkovsky, H. Zhou, A triply interpenetrated microporous metal-organic framework for selective sorption of gas molecules, Inorg. Chem. 46 (2007) 8490–8492. S. Yang, X. Lin, W. Lewis, M. Suyetin, E. Bichoutskaia, J.E. Parker, C.C. Tang, D.R. Allan, P.J. Rizkallah, P. Hubberstey, N.R. Champness, K. Mark Thomas, A.J. Blake, M. Schröder, A partially interpenetrated metal-organic framework for selective hysteretic sorption of carbon dioxide, Nat. Mater. (2012) 11710– 11716, https://doi.org/10.1038/nmat3343. B. Chen, X. Wang, Q. Zhang, X. Xi, J. Cai, H. Qi, S. Shi, J. Wang, D. Yuan, M. Fang, Synthesis and characterization of the interpenetrated MOF-5, J. Mater. Chem. 20 (2010) 3758, https://doi.org/10.1039/b922528e. D.Y. Siberio-Pérez, A.G. Wong-Foy, O.M. Yaghi, A.J. Matzger, Raman spectroscopic investigation of CH4 and N2 adsorption in metal-organic frameworks, Chem. Mater. 19 (2007) 3681–3685, https://doi.org/10.1021/ cm070542g. C. Bin Fan, Z.Q. Liu, L. Le Gong, A.M. Zheng, L. Zhang, C.S. Yan, H.Q. Wu, X.F. Feng, F. Luo, Photoswitching adsorption selectivity in a diaryletheneazobenzene MOF, Chem. Commun. 53 (2017) 763–766, https://doi.org/ 10.1039/C6CC08982H. R. Krishna, J.R. Long, Screening metal-organic frameworks by analysis of transient breakthrough of gas mixtures in a fixed bed adsorber, J. Phys. Chem. C. 115 (2011) 12941–12950, https://doi.org/10.1021/jp202203c. F. Luo, C. Bin Fan, M.B. Luo, X.L. Wu, Y. Zhu, S.Z. Pu, W.-Y. Xu, G.-C. Guo, Photoswitching CO2 capture and release in a photochromic diarylethene metal-organic framework, Angew. Chem. Int. Ed. 53 (2014) 9298–9301, https://doi.org/10.1002/anie.201311124. K. Maity, C.K. Karan, K. Biradha, Porous metal-organic polyhedral framework containing cuboctahedron cages as SBUs with high affinity for H2 and CO2 sorption: a heterogeneous catalyst for chemical fixation of CO2, Chem. A Eur. J. 24 (2018) 10988–10993, https://doi.org/10.1002/chem.201802829.

140

R. Zhu et al. / Coordination Chemistry Reviews 389 (2019) 119–140

[96] G. Zhang, G. Wei, Z. Liu, S.R.J. Oliver, H. Fei, A robust sulfonate-based metalorganic framework with permanent porosity for efficient CO2 capture and conversion, Chem. Mater. 28 (2016) 6276–6281, https://doi.org/10.1021/acs. chemmater.6b02511. [97] H. He, Q. Sun, W. Gao, J.A. Perman, F. Sun, G. Zhu, B. Aguila, K. Forrest, B. Space, S. Ma, A stable metal-organic framework featuring a local buffer environment for carbon dioxide fixation, Angew. Chem. Int. Ed. 57 (2018) 4657–4662, https://doi.org/10.1002/anie.201801122. [98] X. Guo, Z. Zhou, C. Chen, J. Bai, C. He, C. Duan, New rht-type metal-organic frameworks decorated with acylamide groups for efficient carbon dioxide capture and chemical fixation from raw power plant flue gas, ACS Appl. Mater. Interfaces 8 (2016) 31746–31756, https://doi.org/10.1021/acsami.6b13928. [99] S. Mukherjee, B. Joarder, B. Manna, A.V. Desai, A.K. Chaudhari, S.K. Ghosh, Framework-flexibility driven selective sorption of p-xylene over other isomers by a dynamic metal-organic framework, Sci. Rep. 4 (2015) 5761, https://doi.org/10.1038/srep05761. [100] R. Haldar, S.K. Reddy, V.M. Suresh, S. Mohapatra, S. Balasubramanian, T.K. Maji, Flexible and rigid amine-functionalized microporous frameworks based on different secondary building units: supramolecular isomerism, selective CO2 capture, and catalysis, Chem. A Eur. J. 20 (2014) 4347–4356, https://doi. org/10.1002/chem.201303610. [101] M.L. Foo, R. Matsuda, Y. Hijikata, R. Krishna, H. Sato, S. Horike, A. Hori, J. Duan, Y. Sato, Y. Kubota, M. Takata, S. Kitagawa, An adsorbate discriminatory gate effect in a flexible porous coordination polymer for selective adsorption of CO2 over C2H2, J. Am. Chem. Soc. 138 (2016) 3022–3030, https://doi.org/ 10.1021/jacs.5b10491. [102] S. Bhattacharyya, A. Chakraborty, A. Hazra, T.K. Maji, Tetracarboxylate linkerbased flexible Cu II frameworks: efficient separation of CO2 from CO2/N2 and C2H2 from C2H2/C2H4 mixtures, ACS Omega 3 (2018) 2018–2026, https://doi. org/10.1021/acsomega.7b01964. [103] R. Feng, Y.-Y. Jia, Z.-Y. Li, Z. Chang, X.-H. Bu, Enhancing the stability and porosity of penetrated metal-organic frameworks through the insertion of coordination sites, Chem. Sci. 9 (2018) 950–955, https://doi.org/10.1039/ C7SC04192F. [104] Q. Chen, Z. Chang, W.-C. Song, H. Song, H.-B. Song, T.-L. Hu, X.-H. Bu, A controllable gate effect in Cobalt(II) organic frameworks by reversible structure transformations, Angew. Chem. Int. Ed. 125 (2013) 11764–11767, https://doi.org/10.1002/ange.201306304. [105] P. Shen, W.-W. He, D.-Y. Du, H.-L. Jiang, S.-L. Li, Z.-L. Lang, Z.-M. Su, Q. Fu, Y.-Q. Lan, Solid-state structural transformation doubly triggered by reaction temperature and time in 3D metal-organic frameworks: great enhancement of stability and gas adsorption, Chem. Sci. 5 (2014) 1368, https://doi.org/10.1039/c3sc52666f. [106] A. Dey, D. Bairagi, K. Biradha, MOFs with PCU topology for the inclusion of one-dimensional water cages: selective sorption of water vapor, CO2, and dyes and luminescence properties, Cryst. Growth Des. 17 (2017) 3885–3892, https://doi.org/10.1021/acs.cgd.7b00502. [107] P.-Y. Du, H. Li, X. Fu, W. Gu, X. Liu, A 1D anionic lanthanide coordination polymer as an adsorbent material for the selective uptake of cationic dyes from aqueous solutions, Dalton Trans. 44 (2015) 13752–13759, https://doi. org/10.1039/C5DT01848J. [108] A. Dey, S.K. Mandal, K. Biradha, Metal-organic gels and coordination networks of pyridine-3,5-bis(1-methyl-benzimidazole-2-yl) and metal halides: self sustainability, mechano, chemical responsiveness and gas and dye sorptions, CrystEngComm 15 (2013) 9769, https://doi.org/10.1039/c3ce41501e. [109] J.-S. Qin, S.-R. Zhang, D.-Y. Du, P. Shen, S.-J. Bao, Y.-Q. Lan, Z.-M. Su, A Microporous anionic metal-organic framework for sensing luminescence of

[110]

[111]

[112]

[113]

[114]

[115]

[116]

[117]

[118]

[119]

[120]

[121]

[122]

[123]

lanthanide(III) ions and selective absorption of dyes by ionic exchange, Chem. Eur. J. 20 (2014) 5625–5630, https://doi.org/10.1002/chem.201304480. Y. Fu, D. Sun, Y. Chen, R. Huang, Z. Ding, X. Fu, Z. Li, An amine-functionalized titanium metal-organic framework photocatalyst with visible-light-induced activity for CO2 reduction, Angew. Chem. Int. Ed. 51 (2012) 3364–3367, https://doi.org/10.1002/anie.201108357. D. Sun, Y. Fu, W. Liu, L. Ye, D. Wang, L. Yang, X. Fu, Z. Li, Studies on photocatalytic CO2 reduction over NH2-Uio-66(Zr) and its derivatives: towards a better understanding of photocatalysis on metal-organic frameworks, Chem. A Eur. J. 19 (2013) 14279–14285, https://doi.org/ 10.1002/chem.201301728. S. Zhang, L. Li, S. Zhao, Z. Sun, M. Hong, J. Luo, Hierarchical metal-organic framework nanoflowers for effective CO2 transformation driven by visible light, J. Mater. Chem. A. 3 (2015) 15764–15768, https://doi.org/10.1039/ C5TA03322E. S. Zhang, L. Li, S. Zhao, Z. Sun, J. Luo, Construction of interpenetrated ruthenium metal-organic frameworks as stable photocatalysts for CO2 reduction, Inorg. Chem. 54 (2015) 8375–8379, https://doi.org/10.1021/acs. inorgchem.5b01045. B. Garai, A. Mallick, R. Banerjee, Photochromic metal-organic frameworks for inkless and erasable printing, Chem. Sci. 7 (2016) 2195–2200, https://doi.org/ 10.1039/C5SC04450B. H.Y. Wang, J.Y. Ge, C. Hua, C.Q. Jiao, Y. Wu, C.F. Leong, D.M. D’Alessandro, T. Liu, J.L. Zuo, Photo- and electronically switchable spin-crossover Iron(II) metal-organic frameworks based on a tetrathiafulvalene ligand, Angew. Chem. Int. Ed. 56 (2017) 5465–5470, https://doi.org/10.1002/ anie.201611824. P.J. Waller, F. Gándara, O.M. Yaghi, Chemistry of covalent organic frameworks, Acc. Chem. Res. 48 (2015) 3053–3063, https://doi.org/10.1021/ acs.accounts.5b00369. H. Furukawa, O.M. Yaghi, Storage of hydrogen, methane, and carbon dioxide in highly porous covalent organic frameworks for clean energy applications, J. Am. Chem. Soc. 131 (2009) 8875–8883, https://doi.org/10.1021/ja9015765. M. Dogru, M. Handloser, F. Auras, T. Kunz, D. Medina, A. Hartschuh, P. Knochel, T. Bein, A Photoconductive thienothiophene-based covalent organic framework showing charge transfer towards included fullerene, Angew. Chem. 125 (2013) 2992–2996, https://doi.org/10.1002/ange.201208514. Y. Peng, Z. Hu, Y. Gao, D. Yuan, Z. Kang, Y. Qian, N. Yan, D. Zhao, Synthesis of a sulfonated two-dimensional covalent organic framework as an efficient solid acid catalyst for biobased chemical conversion, ChemSusChem 8 (2015) 3208–3212, https://doi.org/10.1002/cssc.201500755. Q. Fang, J. Wang, S. Gu, R.B. Kaspar, Z. Zhuang, J. Zheng, H. Guo, S. Qiu, Y. Yan, 3D porous crystalline polyimide covalent organic frameworks for drug delivery, J. Am. Chem. Soc. 137 (2015) 8352–8355, https://doi.org/ 10.1021/jacs.5b04147. Q. Lu, Y. Ma, H. Li, X. Guan, Y. Yusran, M. Xue, Q. Fang, Y. Yan, S. Qiu, V. Valtchev, Postsynthetic functionalization of three-dimensional covalent organic frameworks for selective extraction of lanthanide ions, Angew. Chem. Int. Ed. 57 (2018) 6042–6048, https://doi.org/10.1002/ anie.201712246. C. Bonneau, O. Delgado-Friedrichs, M. O’Keeffe, O.M. Yaghi, Three-periodic nets and tilings: minimal nets, Acta Crystallogr., A 60 (2004) 517–520, https://doi.org/10.1107/S0108767304015442. X. Guan, Y. Ma, H. Li, Y. Yusran, M. Xue, Q. Fang, Y. Yan, V. Valtchev, S. Qiu, Fast, ambient temperature and pressure ionothermal synthesis of threedimensional covalent organic frameworks, J. Am. Chem. Soc. 140 (2018) 4494–4498, https://doi.org/10.1021/jacs.8b01320.