Novel Hierarchical Meso-Microporous Hydrogen-Bonded Organic

ACS2GO © 2019. ← → → ←. loading. To add this web app to the home screen open the browser option menu and tap on Add to homescreen...
0 downloads 0 Views 2MB Size
Subscriber access provided by University of Otago Library

Applications of Polymer, Composite, and Coating Materials

A Novel Hierarchical Meso-Microporous Hydrogenbonded Organic Framework for Selective Separation of Acetylene and Ethylene versus Methane Qi Yin, Yu-Lin Li, Lan Li, Jian Lü, Tian-Fu Liu, and Rong Cao ACS Appl. Mater. Interfaces, Just Accepted Manuscript • DOI: 10.1021/acsami.9b03696 • Publication Date (Web): 22 Apr 2019 Downloaded from http://pubs.acs.org on April 22, 2019

Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.

is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.

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

ACS Applied Materials & Interfaces

SYNOPSIS TOC

A novel hierarchical meso-microporous hydrogen-bonded organic framework (PFC-2) was constructed which possesses the largest open channels relative to all known HOFs and exhibits highly selective separation of acetylene and ethylene versus methane. Compared with the performance of an analogue structure PFC-1, we found the high selectivity of PFC-2 can be ascribed to the extensively existed unpaired hydrogen bond acceptor C=O groups, demonstrating an effective strategy to optimize gas adsorption/separation performance of HOF materials.

ACS Paragon Plus Environment

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

Page 2 of 23

A Novel Hierarchical Meso-Microporous Hydrogenbonded Organic Framework for Selective Separation of Acetylene and Ethylene versus Methane ‖

Qi Yin,†,‡ Yu-Lin Li,‡, Lan Li,‡ Jian Lü,┸,§ Tian-Fu Liu,*,‡, and Rong Cao*,†,‡ †

Department of Chemistry, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China.



State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian, 350002, P. R. China.



University of Chinese Academy of Sciences, No.19 (A) Yuquan Road, Shijingshan District,

Beijing, 100049, P. R. China ┸

Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of

Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, P.R. China. §

Samara Center for Theoretical Materials Science (SCTMS), Samara State Technical University, Samara 443100, Russia.

KEYWORDS: hydrogen-bonded organic frameworks, light hydrocarbons, selective adsorption.

1 ACS Paragon Plus Environment

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

ACS Applied Materials & Interfaces

ABSTRACT

Herein we construct a novel three-dimension (3D) hydrogen-bonded organic framework (PFC-2) with a hierarchical meso-microporous structure, which possesses the largest open channels relative to all known HOFs and exhibits highly selective separation of acetylene and ethylene versus methane at ambient atmosphere. Comparison on the adsorption behaviors of PFC-2 and an analogue structure PFC-1 clearly shows that the extensively existed unpaired hydrogen bond acceptor C=O groups in PFC-2 dramatically increase the affinity between gas molecules and frameworks, resulting in high isosteric heats of adsorption (Qst) and better selectivity toward C2 hydrocarbons to methane. The study presented here demonstrated an effective strategy to optimize gas adsorption/separation performance of HOF materials.

Introduction As one part of the most important petrochemicals, C2 hydrocarbons, such as acetylene and ethylene, are basic feedstock in the petrochemical industry.1 Pyrolysis of fossil oil is the main way to obtain these gases, but the resulting production also contains a part of methane.2 Therefore, separation of methane from such light hydrocarbons is substantially important for the best use of petrochemicals. Traditional separation methods are the cryogenic distillation technology and gas–liquid absorptive separation, which are either poorly efficient or very costly.3 Therefore, extensive attention has been paid to develop alternative technologies, such as membrane separation, solid adsorbent separation and liquid adsorbent separation toward C2 hydrocarbons/methane separation at ambient atmosphere for lower energy cost.

2 ACS Paragon Plus Environment

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

Page 4 of 23

Various porous materials, such as zeolites4, metal-organic frameworks (MOFs)5-9, covalent organic frameworks (COFs)10, porous organic polymers11, activated carbons12, and carbon nanotubes13 have been explored as solid adsorbents to realize olefin/paraffin separation in the development of solid sorbents field.14 Hydrogen-bonded organic frameworks (HOFs) is a kind of novel ordered porous materials that have attracted significant attentions recently. HOFs have the properties of permanent porosity15-17, high specific surface area18-20, predictable structure21,22, tailored pore size/shape23, mild synthetic conditions19, and solution processability23. Since the first HOF material was found in 200524, a series of HOFs have been reported for the applications on, for example, gas selective adsorption25 and guest molecule recognition26. However, most of the reported structures are microporous or even non-porous, and HOFs with hierarchical mesomicropores are unprecedented until now. We expect that the hierarchical arrangement of micro/mesopores could optimize the adsorption/separation performance of adsorbents, and most importantly, could provide insight into the relationship between structure-properties for rational design of HOF materials. Herein we report a HOF, denoted as PFC-2 (PFC = Porous materials from FJIRSM, CAS), with hierarchical meso-microporous structure, constructed by 1,3,6,8-tetrakis (p-benzoic acid) pyrene (H4TBAPy). The activated material adsorbs higher amount of ethylene and acetylene over methane, showing potential applications for efficient selective separations of C2 hydrocarbons versus methane binary gas mixtures at ambient atmosphere. The selective adsorption behaviors can be ascribed to the higher affinity of residual hydrogen bond acceptor C=O groups toward gas molecules with higher polarizability, presenting a new strategy to design HOF materials for optimized gas adsorption/separation performance. Results and discussion.

3 ACS Paragon Plus Environment

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

ACS Applied Materials & Interfaces

Single crystal X-ray diffraction reveals that PFC-2 crystallizes in trigonal space group 𝑅3𝑚. Each building block is connected with four neighbouring ones by four hydrogen bonds (crystallographically dependent) between -COOH groups with the O-H···O angle being 171.929o. The O-H···O distance is 2.492 Å, which falls into the strong hydrogen bonding interactions range of 2.49 to 3.15 Å according to literature reports (Figure 1a, 1b) 27. Topologically, the organic building blocks can be considered as 4-connected nodes to form a three-dimensional body-centered network with nbo {6482} topology (Figure S1). The nbo network undergoes 5-fold interpenetration to construct a distinctive three-dimensional framework, and there exist a vast amount of intermolecular π-π interactions between the pyrene and benzene rings. The nbo net interpenetrated along c axis but still leaving hexagonal mesochannels (29.7 Å) and triangle micro-channels (10.7 Å) alternately and periodically arranged along [001] direction (Figure 1c). The potential solvent accessible void space accounts for approximately 68.1 % of the whole crystal volume as estimated by PLATON28, which is a high value among HOF materials. The powder X-ray diffraction (PXRD) pattern of as-synthesized PFC-2 is consistent with the simulated pattern, indicating the phase purity of PFC-2 in bulk amount (Figure 2a). Desolvated PFC-2 was obtained through the operation of solvent exchange with acetone to remove guest solvent molecules such as DMF and EtOH, and followed by vacuum at 90 oC for 5 hours. The persistence of crystallinity during activation process was confirmed by PXRD which well matched with the pristine sample. The highly available void space prompts us to examine the gas adsorption properties of PFC-2. Steep increase around the pressure P/P0=0.2 and an evidently hysteresis behavior on N2 isotherm (77 K, Figure 2b) prove the mesoporous characteristic of PFC-2. N2 uptake of PFC-2 is 415

4 ACS Paragon Plus Environment

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

Page 6 of 23

cm3/g (STP) and Brunauer-Emmett-Teller (BET) surface area is 1014 m2/g, matched well with the simulated surface area (1120 m2/g) by Zeo++ software package29 and being of an excellent value among HOF materials (Table S2). Not-Local Density functional theory (NLDFT) pore size distribution analysis deduced from N2 isotherm reveals that there are two types of pores (Figure S6), with apertures about 10.2 Å and 29.2 Å, which well matched with the crystallographic data when van der Waals contact is considered. As far as we know, PFC-2 possess the largest open channels relative to all known HOFs. Compared with other well-explored porous materials, for example, MOFs, zeolite, molecular sieves, the structure-property relation for HOF materials is still very unclear at current stage, and very few studies in HOF field have disclosed effective strategies for optimized adsorption performance. Taking lessons from MOFs30,31 and molecular sieves32, we know that the functional groups (open metal sites, alkyl chains, etc.) on pore surface could dramatically influence the adsorption/separation behaviors. Therefore, we speculate that the extensively existed residual hydrogen bond acceptors C=O group inside pores of PFC-2 may have diverse affinities toward different gas molecules and result in better separation performance. For better understanding how structure affects gas adsorption/separation behaviors of HOFs, besides PFC-2, we also synthesized PFC-1 and investigated their gas adsorption capacity toward acetylene, ethylene, and methane (Figure 3a, 3b, S7-8). PFC-1 is a HOF material constructed by the same ligands as PFC2 but without unpaired hydrogen bond acceptors remaining in the self-assembled structure (Figure S2).18 Interestingly, for both C2H2 and C2H4, PFC-2 has higher uptake capacity than PFC-1. As shown in Table 2, PFC-2 adsorbs 76.3 cm3/g C2H2 at 273 K, which is the third highest value in all known HOFs and also higher than some organic molecular porous materials (such as

5 ACS Paragon Plus Environment

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

ACS Applied Materials & Interfaces

TBC[4], CB[6]). At 298K, PFC-2 has a C2H2 uptake of 47.9 cm3/g, which is the fifth highest among all known HOFs. For C2H4, PFC-2 has an uptake of 62.2 cm3/g at 273 K, which is the second highest among all known HOFs (Table 3). At 298 K, PFC-2 adsorbs 41.1 cm3/g of C2H4. In contrast, PFC-1 was found to have significantly lower uptake toward C2H2. The isosteric heats of adsorption (Qst), which play a significant role in adsorptive selectivity, were calculated by the virial method to evaluate the affinity of pore surface between gas molecules.2 For PFC-2, the near zero-coverage Qst for C2H2 (28.4 KJ/mol) and C2H4 (23.8 KJ/mol) are much higher than that for methane (11.2 KJ/mol) (Figure S9). While for PFC-1, Qst values for these three gas are very closed (17.4 KJ/mol, 18.4 KJ/mol, and 15.6 KJ/mol for C2H2, C2H4, and CH4, respectively) (Figure S10). Both PFC-1 and PFC-2 have smaller Qst toward CH4 because CH4 has lower polarizability than C2H2 and C2H4 (Table S5). It’s worth to note that PFC-2 displays evident Qst difference between the very similar molecules of C2H2 and C2H4, while PFC-1 does not show a preference. Ideal adsorbed solution theory (IAST) of Myers and Prausnitz was then used to perform calculations of gas mixture selectivity at room temperature (298 K) (Figure 3a, 3b).33 As shown in Figure 3c, for PFC-2, adsorption selectivities were determined to be 27, and 17 for C2H2/CH4 (50/50, v/v), and C2H4/CH4 (50/50, v/v) at pressure of 1 kPa, respectively. Adsorption selectivities of PFC-1 were 6 and 6 for C2H2/CH4 (50/50, v/v), and C2H4/CH4 (50/50, v/v) at pressure of 1 kPa, respectively, evidently lower than those of PFC-2 (Figure S11). These values are consistent with the trend disclosed by Qst. Stronger affinities of the pore surface to C2H2 and C2H4 over CH4 endow PFC-2 better selectivity than PFC-1 which has only slight difference toward three gases. As pressure increased, more active sites accounting for the selective gas

6 ACS Paragon Plus Environment

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

Page 8 of 23

adsorption behaviors are occupied by preferred gas molecules, causing decreased selectivity toward gas molecules. Based on these results, we can confidently conclude that the uptake capacity and selectivity performance of PFC-1 and PFC-2 could be influenced by the following factors: Firstly, although these two structures are based on identical ligands, highly accessible void space (67.8% for PFC2 vs 55.6% for PFC-1) results PFC-2 has higher uptake for hydrocarbons gas. Secondly, high number of unpaired hydrogen bond acceptor (C=O) groups located on the pore surface of PFC-2 makes framework stronger affinity toward light hydrocarbons (higher Qst values) and hence results in higher selectivities than PFC-1. Thirdly, acetylene (pKa = 24) has higher acidity than ethylene (pKa = 44). This disparity causes dramatically higher uptake and Qst for C2H2 than C2H4 in PFC-2, where the polar unpaired C=O groups are widely spread inside pore. In contrast, without unpaired C=O group in pore surface, PFC-1 did not show apparent discrimination toward these two molecules. Conclusion In summary, for the first time, a unique 5-fold interpenetrated PFC-2 material with a hierarchical meso-microporous structure has been successfully constructed. The material possesses the largest open channels relative to all known HOFs. Compared with the adsorption performance of an analogous structure, we prove that the unpair hydrogen bond acceptors in PFC-2 dramatically improve the adsorption capacity, Qst and selectivity toward C2 hydrocarbon to methane. Moreover, the polar surface of PFC-2 endows the framework with high affinity toward the gas molecules with high acidity (pKa). With the high separation selectivity for

7 ACS Paragon Plus Environment

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

ACS Applied Materials & Interfaces

acetylene/ethylene over methane, PFC-2 presents a promising candidate for fuel gas purification and separation of acetylene and ethylene versus methane. ASSOCIATED CONTENT Supporting Information Electronic Supplementary Information (ESI) available: Synthesis and characterization of PFC2, PXRD, TGA, and sorption isotherms. CCDC 1883913. This material is available free of charge via the Internet at http://pubs.acs.org.” AUTHOR INFORMATION Corresponding Author *[email protected], *[email protected]. Author Contributions All authors have given approval to the final version of the manuscript. Funding Sources The authors thank National Key Research and Development Program of China (Grant No. 2018YFA020860), “Strategic Priority Research Program” of the Chinese Academy of Sciences (Grant No. XDB20000000), the Key Research Program of the Chinese Academy of Sciences (Grant NO. ZDRW-CN-2016-1), National Natural Science Foundation of China (NSFC, Grant

8 ACS Paragon Plus Environment

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

Page 10 of 23

No. 21520102001, 21871267 ), Key Research Program of Frontier Science, CAS (QYZDJ-SSWSLH045). Notes The authors declare no competing financial interests. ABBREVIATIONS HOFs, Hydrogen-bonded organic frameworks; H4TBAPy, 1,3,6,8-tetrakis(p-benzoic acid)pyrene; PFC, Porous materials from Fjirsm, CAS; BET, Brunauer-Emmett-Teller.

9 ACS Paragon Plus Environment

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

ACS Applied Materials & Interfaces

Tables. Table 1. Comparison of uptakes of acetylene, ethylene, and methane for PFC-1 and PFC-2. adsorbent

adsorbate CH4

PFC-2

C2H2 C2H4 CH4

PFC-1

C2H2 C2H4

T [K]

Uptake cm3/g

273 K

16.8

298 K

10.8

273 K

75.5

298 K

47.9

273 K

61.6

298 K

41.1

273 K

10.5

298 K

6.9

273 K

48.2

298 K

28.5

273 K

52.7

298 K

29.2

Qst,n→0 [KJ/mol] 11.3 28.3 23.7 15.6 17.4 18.4

10 ACS Paragon Plus Environment

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

Page 12 of 23

Table 2. Comparison of C2H2 uptake capacities of PFC-2 with other HOFs and OMOMs. Materials

HOFs

OMOMs

C2H2

Reference

273K

298K

HOF-5a

182[a]

102[a]

34

HOF-BTB

110.3[b]

64.3[b]

35

PFC-2

76

48

This work

HOF-11a

74[a]

45[a]

36

HOF-1a

63[a]

55[a]

37

SOF-1a

61

50

38

HOF-3a

58[a]

47[a]

39

PFC-1

48

28

This work

HOF-TCBP

-

~35[b]

23

CB[6]

-

52

40

TBC[4]

-

18

41

[a]

Examined at 296 K

[b]

Examined at 295 K

11 ACS Paragon Plus Environment

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

ACS Applied Materials & Interfaces

Table 3. Comparison of C2H4 uptake capacities of PFC-2 with other HOFs. HOFs

C2H4

Reference

273K

298K

HOF-BTB

85.3[a]

55.7[a]

35

PFC-2

62.2

42.6

This work

HOF-TCBP

-

~32[a]

23

PFC-1

52.7

29.2

This work

HOF-4a

17.3[b]

11.1[b]

42

HOF-1a

8.3[b]

~2[b]

37

[a] Examined at 295 K [b] Examined at 296 K

12 ACS Paragon Plus Environment

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

Page 14 of 23

Figures.

Figure. 1. The crystal structure of PFC-2 featuring a) One building block and its direct environment. b) Hydrogen bonds length and angle. c) Representation of the porous framework and two kinds of channels.

13 ACS Paragon Plus Environment

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

ACS Applied Materials & Interfaces

Figure. 2. a) PXRD patterns of simulated PFC-2 (black), as-synthesized PFC-2 (red) and desolvated PFC-2 (green); b) N2 adsorption-desorption isotherms (77 K) of desolvated PFC-2.

14 ACS Paragon Plus Environment

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

Page 16 of 23

Figure. 3. Single-component sorption isotherms for CH4, C2H2, and C2H4 of a) PFC-2; b) PFC-1 at 298 K; c) Comparison of the IAST calculations of C2H2/CH4 (50:50) and C2H4/CH4 (50:50) adsorption selectivities for PFC-2 at 298 K.

15 ACS Paragon Plus Environment

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

ACS Applied Materials & Interfaces

REFERENCES (1) Baker, R. W., Future Directions of Membrane Gas Separation Technology. Industrial & Engineering Chemistry Research 2002, 41, 1393-1411. (2) Li, L.; Wang, X.; Liang, J.; Huang, Y.; Li, H.; Lin, Z.; Cao, R., Water-Stable Anionic Metal-Organic Framework for Highly Selective Separation of Methane from Natural Gas and Pyrolysis Gas. ACS Applied Materials & Interfaces 2016, 8, 9777-9781. (3) Magnowski, N. B. K.; Avila, A. M.; Lin, C. C. H.; Shi, M.; Kuznicki, S. M., Extraction of Ethane from Natural Gas by Adsorption on Modified ETS-10. Chemical Engineering Science 2011, 66, 1697-1701. (4) Kuznicki, S. M.; Bell, V. A.; Nair, S.; Hillhouse, H. W.; Jacubinas, R. M.; Braunbarth, C. M.; Toby, B. H.; Tsapatsis, M., A Titanosilicate Molecular Sieve with Adjustable Pores for Size-selective Adsorption of Molecules. Nature 2001, 412, 720-724. (5) Li, J.-R.; Kuppler, R. J.; Zhou, H.-C., Selective Gas Adsorption and Separation in Metal-Organic Frameworks. Chemical Society Reviews 2009, 38, 1477-1504. (6) Bloch, E. D.; Queen, W. L.; Krishna, R.; Zadrozny, J. M.; Brown, C. M.; Long, J. R., Hydrocarbon Separations in a Metal-Organic Framework with Open Iron(II) Coordination Sites. Science 2012, 335, 1606-1610. (7) Farha, O. K.; Eryazici, I.; Jeong, N. C.; Hauser, B. G.; Wilmer, C. E.; Sarjeant, A. A.; Snurr, R. Q.; Nguyen, S. T.; Yazaydin, A. O.; Hupp, J. T., Metal-Organic Framework Materials with Ultrahigh Surface Areas: Is the Sky the Limit? Journal of the American Chemical Society 2012, 134 (36), 15016-15021.

16 ACS Paragon Plus Environment

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

Page 18 of 23

(8) Furukawa, H.; Cordova, K. E.; O'Keeffe, M.; Yaghi, O. M., The Chemistry and Applications of Metal-Organic Frameworks. Science 2013, 341, 974-976. (9) Wei, N.; Zhang, Y.; Liu, L.; Han, Z.-B.; Yuan, D.-Q., Pentanuclear Yb(III) Clusterbased Metal-Organic Frameworks as Heterogeneous Catalysts for CO2 Conversion. Applied Catalysis B: Enviromnental 2017, 219, 603-610. (10) Ma, H.; Ren, H.; Meng, S.; Yan, Z.; Zhao, H.; Sun, F.; Zhu, G., A 3D Microporous Covalent Organic Framework with Exceedingly High C3H8/CH4 and C2 Hydrocarbon/CH4 Selectivity. Chemical Communications 2013, 49, 9773-9775. (11) Maji, T. K.; Uemura, K.; Chang, H. C.; Matsuda, R.; Kitagawa, S., Expanding and Shrinking Porous Modulation Based on Pillared-layer Coordination Polymers Showing Selective Guest Adsorption. Angewandte Chemie-International Edition 2004, 43, 32693272. (12) Bu, J.; Loh, G.; Gwie, C. G.; Dewiyanti, S.; Tasrif, M.; Borgna, A., Desulfurization of Diesel Fuels by Selective Adsorption on Activated Carbons: Competitive Adsorption of Polycyclic Aromatic Sulfur Heterocycles and Polycyclic Aromatic Hydrocarbons. Chemical Engineering Journal 2011, 166, 207-217. (13) Zhao, J. J.; Buldum, A.; Han, J.; Lu, J. P., Gas Molecule Adsorption in Carbon Nanotubes and Nanotube Bundles. Nanotechnology 2002, 13, 195-200. (14) Rege, S. U.; Padin, J.; Yang, R. T., Olefin/Paraffin Separations by Adsorption: PiComplexation vs. Kinetic Separation. AIChE Journal 1998, 44, 799-809.

17 ACS Paragon Plus Environment

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

ACS Applied Materials & Interfaces

(15) He, Y.; Xiang, S.; Chen, B., A Microporous Hydrogen-bonded Organic Framework for Highly Selective C2H2/C2H4 Separation at Ambient Temperature. Journal of the American Chemical Society 2011, 133 (37), 14570-14573 (16) Zhang, K. D.; Tian, J.; Hanifi, D.; Zhang, Y.; Sue, A. C.; Zhou, T. Y.; Zhang, L.; Zhao, X.; Liu, Y.; Li, Z. T., Toward a Single-layer Two-dimensional Honeycomb Supramolecular Organic Framework in Water. Journal of the American Chemical Society 2013, 135 (47), 17913-17918 (17) Lu, J.; Perez-Krap, C.; Suyetin, M.; Alsmail, N. H.; Yan, Y.; Yang, S.; Lewis, W.; Bichoutskaia, E.; Tang, C. C.; Blake, A. J.; Cao, R.; Schroder, M., A Robust Binary Supramolecular Organic Framework (SOF) with High CO2 Adsorption and Selectivity. Journal of the American Chemical Society 2014, 136 (37), 12828-12831. (18) Mastalerz, M.; Oppel, I. M., Rational Construction of an Extrinsic Porous Molecular Crystal with an Extraordinary High Specific Surface Area. Angewandte ChemieInternational Edition. 2012, 51, 5252-5255. (19) Yin, Q.; Zhao, P.; Sa, R. J.; Chen, G. C.; Lu, J.; Liu, T. F.; Cao, R., An Ultra-Robust and Crystalline Redeemable Hydrogen-Bonded Organic Framework for Synergistic Chemo-Photodynamic Therapy. Angewandte Chemie-International Edition 2018, 57, 7691-7696. (20) Li, P.; Li, P.; Ryder, M. R.; Liu, Z.; Stern, C. L.; Farha, O. K.; Stoddart, F., "Interpenetration Isomerism" of Triptycene-Based Hydrogen-Bonded Organic Frameworks. Angewandte Chemie-International Edition 2019. 58, 1664-1669.

18 ACS Paragon Plus Environment

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

Page 20 of 23

(21) Hisaki, I.; Nakagawa, S.; Ikenaka, N.; Imamura, Y.; Katouda, M.; Tashiro, M.; Tsuchida, H.; Ogoshi, T.; Sato, H.; Tohnai, N.; Miyata, M., A Series of Layered Assemblies of Hydrogen-Bonded, Hexagonal Networks of C3-Symmetric Pi-Conjugated Molecules: A Potential Motif of Porous Organic Materials. Journal of the American Chemical Society 2016, 138, 6617-6628. (22) Cao, H.-L.; Zhou, J.-R.; Cai, F.-Y.; Lü, J.; Cao, R., Two-Component Pharmaceutical Cocrystals Regulated by Supramolecular Synthons Comprising Primary N•••H•••O Interactions. Crystal Growth & Design 2019, 19 (1), 3-16. (23) Hu, F.; Liu, C.; Wu, M.; Pang, J.; Jiang, F.; Yuan, D.; Hong, M., An Ultrastable and Easily Regenerated Hydrogen-Bonded Organic Molecular Framework with Permanent Porosity. Angewandte Chemie-International Edition 2017, 56, 2101-2104. (24) Sozzani, P.; Bracco, S.; Comotti, A.; Ferretti, L.; Simonutti, R., Methane and Carbon Dioxide Storage in a Porous Van Der Waals Crystal. Angewandte Chemie-International Edition 2005, 44, 1816-1820. (25) Lu, J.; Cao, R., Porous Organic Molecular Frameworks with Extrinsic Porosity: A Platform for Carbon Storage and Separation. Angewandte Chemie-International Edition 2016, 55, 9474-9480. (26) Wang, H. L.; Wu, H.; Kan, J. L.; Chang, G. G.; Yao, Z. Z.; Li, B.; Zhou, W.; Xiang, S. C.; Zhao, J. C. G.; Chen, B. L., A Microporous Hydrogen-bonded Organic Framework with Amine Sites for Selective Recognition of Small Molecules. Journal of Materials Chemistry A 2017, 5, 8292-8296.

19 ACS Paragon Plus Environment

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

ACS Applied Materials & Interfaces

(27) Desiraju, G., India Steiner, Thomas,, The Weak Hydrogen Bond ,In Structural Chemistry and Biology. Oxford University Press, USA 2001, 108-113. (28) Spek, A. L., PLATON, A Multipurpose Crystallographic Tool, Utrecht University: Utrecht, the Netherlands, 2005. (29) Willems, T. F.; Rycroft, C.; Kazi, M.; Meza, J. C.; Haranczyk, M., Algorithms and Tools for High-throughput Geometry-based Analysis of Crystalline Porous Materials. Microporous and Mesoporous Materials 2012, 149, 134-141. (30) Li, J. R.; Sculley, J.; Zhou, H. C., Metal-Organic Frameworks for Separations. Chemical Reviews 2012, 112, 869-932. (31) Zhang, Y.; Wang, Y.; Liu, L.; Wei, N.; Gao, M. L.; Zhao, D.; Han, Z. B., Robust Bifunctional Lanthanide Cluster Based Metal-Organic Frameworks (MOFs) for Tandem Deacetalization-Knoevenagel Reaction. Inorganic Chemistry 2018, 57 (4), 2193-2198. (32) Wang, Q. M.; Shen, D. M.; Bulow, M.; Lau, M. L.; Deng, S. G.; Fitch, F. R.; Lemcoff, N. O.; Semanscin, J., Metallo-Organic Molecular Sieve for Gas Separation and Purification. Microporous and Mesoporous Materials 2002, 55, 217-230.

(33) Myers, A. L.; Prausnitz, J. M., Thermodynamics of Mixed-gas Adsoprtion. AIChE Journal 1965, 11, 121-127. (34) Wang, H.; Li, B.; Wu, H.; Hu, T. L.; Yao, Z.; Zhou, W.; Xiang, S.; Chen, B. A Flexible Microporous Hydrogen-Bonded Organic Framework for Gas Sorption and Separation. Journal of the American Chemical Society 2015, 137 (31), 9963-9970.

20 ACS Paragon Plus Environment

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

Page 22 of 23

(35) Yoon, T. U.; Baek, S. B.; Kim, D.; Kim, E. J.; Lee, W. G.; Singh, B. K.; Lah, M. S.; Bae, Y. S.; Kim, K. S. Efficient separation of C2 hydrocarbons in a permanently porous hydrogenbonded organic framework. Chemical Communications 2018, 54 (67), 9360-9363. (36) Yang, W.; Wang, J. W.; Wang, H. L.; Bao, Z. B.; Zhao, J. C. G.; Chen, B. L. Highly Interpenetrated Robust Microporous Hydrogen-Bonded Organic Framework for Gas Separation. Crystal Growth & Design 2017, 17 (11), 6132-6137. (37) He, Y.; Xiang, S.; Chen, B. A microporous hydrogen-bonded organic framework for highly selective C2H2/C2H4 separation at ambient temperature. Journal of the American Chemical Society 2011, 133 (37), 14570-14573. (38) Yang, W.; Greenaway, A.; Lin, X.; Matsuda, R.; Blake, A. J.; Wilson, C.; Lewis, W.; Hubberstey, P.; Kitagawa, S.; Champness, N. R.; Schroder, M. Exceptional thermal stability in a supramolecular organic framework: porosity and gas storage. Journal of the American Chemical Society 2010, 132 (41), 14457-14469. (39) Li, P.; He, Y.; Zhao, Y.; Weng, L.; Wang, H.; Krishna, R.; Wu, H.; Zhou, W.; O'Keeffe, M.; Han, Y.; Chen, B. A rod-packing microporous hydrogen-bonded organic framework for highly selective separation of C2H2/CO2 at room temperature. Angewandte Chemie-International Edition 2015, 54 (2), 574-577. (40) Lim, S.; Kim, H.; Selvapalam, N.; Kim, K.-J.; Cho, S. J.; Seo, G.; Kim, K. Cucurbit[6]uril: Organic Molecular Porous Material with Permanent Porosity, Exceptional Stability, and Acetylene Sorption Properties. Angewandte Chemie-International Edition 2008, 120 (18), 34003403. (41) Thallapally, P. K.; Dobrzańska, L.; Gingrich, T. R.; Wirsig, T. B.; Barbour, L. J.; Atwood, J. L. Acetylene Absorption and Binding in a Nonporous Crystal Lattice. Angewandte ChemieInternational Edition 2006, 118 (39), 6656-6659. (42) Li, P.; He, Y.; Arman, H. D.; Krishna, R.; Wang, H.; Weng, L.; Chen, B. A microporous six-fold interpenetrated hydrogen-bonded organic framework for highly selective separation of C2H4/C2H6. Chemical Communications 2014, 50 (86), 13081-13084.

21 ACS Paragon Plus Environment

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

ACS Applied Materials & Interfaces

BRIEFS A novel hierarchical meso-microporous hydrogen-bonded organic framework (PFC-2) was constructed which possesses the largest open channels relative to all known HOFs and exhibits highly selective separation of acetylene and ethylene versus methane. Compared with the performance of an analogue structure PFC-1, we found the high selectivity of PFC-2 can be ascribed to the extensively existed unpaired hydrogen bond acceptor C=O groups, demonstrating an effective strategy to optimize gas adsorption/separation performance of HOF materials. SYNOPSIS

22 ACS Paragon Plus Environment