Highly Selective Gaseous and Liquid-Phase Separation over a Novel

Subscriber access provided by NAGOYA UNIV

Energy, Environmental, and Catalysis Applications

Highly Selective Gaseous and Liquid-Phase Separation over a Novel Cobalt (II) Metal-Organic Framework Jingui Duan, Rui Yan, Linlin Qin, Yong Wang, Lili Wen, Shaoxiao Cheng, Hui Xu, and Pingyun Feng ACS Appl. Mater. Interfaces, Just Accepted Manuscript • DOI: 10.1021/acsami.8b02714 • Publication Date (Web): 20 Jun 2018 Downloaded from http://pubs.acs.org on June 20, 2018

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

ACS Applied Materials & Interfaces

Highly

Selective

Gaseous

and

Liquid-Phase

Separation over a Novel Cobalt (II) Metal-Organic Framework Jingui Duan,‡c Rui Yan,‡a Linlin Qin,a Yong Wang,b Lili Wen,*a,b Shaoxiao Cheng,a Hui Xu*a and Pingyun Feng*b a

Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, 430079, China.

b

Department of Chemistry, University of California, Riverside, California 92521, United States. c

State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemical

Engineering, Jiangsu National Synergetic Innovation Centre for Advanced Materials, Nanjing Tech University, Nanjing 210009, China. ‡ Jingui Duan and Rui Yan contributed equally to this work. Corresponding Authors. E-mails: [email protected] (L. L. Wen), [email protected] (H. Xu), [email protected] (P. Y. Feng). ORCID Jingui Duan: 0000-0002-8218-1487 Rui Yan: 0000-0001-7965-9024

1 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 28

Lili Wen: 0000-0002-8639-2978 Hui Xu: 0000-0003-1999-9806 Pingyun Feng: 0000-0003-3684-577X KEYWORDS: MOFs, mild recognition sites, gas adsorption/separation, submicron-scale, liquidphase separation ABSTRACT: The mild recognition sites of oxygen atoms and phenyl rings from 5-(4-pyridyl)methoxyl isophthalic acid (5,4-PMIA2-) moieties and tetrakis(4-pyridyloxymethylene) methane (TPOM) linkers inside the channels of a novel three-dimensional microporous MOF [Co2(5,4PMIA)2(TPOM)0.5]·xSolvent (1), are presumed to provide pore environments with moderate contacts toward guests, as indicated by Grand Canonical Monte Carlo simulations, which appear to be beneficial for adsorption and separation applications. As expected, 1 represents one of the rare examples that show both a high storage capacity of C2Hn and good adsorption selectivity of C2Hn/CH4 and CO2/CH4 under ambient conditions, and yet, it has significantly lower energy consumption for regeneration. In addition, a validated submicro-1-based microsolid phase extraction (µ-SPE) method for the determination of trace mono-hydroxylated PAHs (OH-PAHs) in complex human urine was developed with satisfactory sensitivity and good precision by online coupling to liquid chromatography-mass spectrometry (LC-MS), which represents the first example of a mixed-ligand MOF applied as an efficient sorbent for µ-SPE. ■ INTRODUCTION Metal−organic frameworks (MOFs),1-2 also termed as porous coordination polymers (PCPs),3 are an emerging class of crystalline porous materials comprised of inorganic metal ions or clusters and appropriate organic linkers. MOFs feature a high tunability of the specific surface area 2 ACS Paragon Plus Environment

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


and uniform pore sizes, making them promising materials as adsorbents for gas storage as well as gaseous and liquid-phase separation.4-7 In particular, with a wide range of availabilities in metals or metal clusters and organic ligands, MOF materials can be synthesized with different functional sites within the MOF pore space. This provides fruitful opportunities to enhance the overall uptake capacity of the material and the molecular separation efficiency.8 The purification of methane from other light hydrocarbons (C2Hn; n = 2, 4, 6) and CO2 is an important and challenging task in industrial application.9 The purification is currently achieved by using the energy-consuming technology cryogenic distillation. A cost- and energy-efficient separation technology is highly desirable. Extensive efforts to develop energy-saving materials for the efficient separation of methane from C2Hn and CO2 at ambient conditions have particularly focused on MOFs as solid sorbents.10 To achieve a high efficiency for adsorption/selectivity and low energy cost for the regeneration of MOFs, a number of hurdles still remain to be overcome. In general, immobilizing strong recognition sites within MOFs for higher gas uptake and selectivity is prone to increase the high sorption energy toward guest molecules, whereas weak binding sites usually result in lower gas selectivity.11 Similar material design principles also apply for the synthesis of efficient adsorbents for liquid-phase separation. Given the mutagenicity, toxicity and resistance toward biodegradation of polycyclic aromatic hydrocarbons (PAHs), considerable studies have concentrated on the distribution of PAHs in the environment.12 Mono-hydroxylated PAHs (OH-PAHs) are often utilized as biomarkers to assess personal exposure to atmospheric PAHs.13 The determination of OH-PAHs in biological samples is challenging because of their very low concentration levels. Notably, micro-solid phase extraction (µ-SPE), introduced as the miniaturization of solid phase 3 ACS Paragon Plus Environment


Page 4 of 28

extraction (SPE), exhibits promising and environmentally friendly application in this area.14 Especially, the pre-column packed with no more than 500 mg of sorbent can be online coupled to a chromatographic system by a switch valve. In this regard, the exploration of efficient µ-SPE sorbents acting as liquid-phase separators or concentrators for sample pretreatment prior to chromatographic analysis could help improve the detection efficiency. By combining the unique structural features of MOFs and the high efficiency of µ-SPE, MOFs could make a great contribution in this area. Nonetheless, the potential application of MOFs as excellent sorbents for µ-SPE remains much less explored thus far.15 Motivated by the aforementioned challenges and prospects, by employing the ligand 5-(4pyridyl)-methoxyl isophthalic acid (5,4-PMIA) to assemble with Co(II) ions in the presence of flexible linker tetrakis(4-pyridyloxymethylene) methane (TPOM), a novel three-dimensional (3D) microporous MOF [Co2(5,4-PMIA)2(TPOM)0.5]·xSolvent (1) was successfully achieved (Scheme 1). The mild recognition sites of oxygen atoms and phenyl rings from 5,4-PMIA2moieties and flexible TPOM linkers inside the channels of 1, are intended to provide pore environments with moderate contacts toward guests, to facilitate gas storage and separation as well as extraction selectivity towards OH-PAHs via synergistic effects. As expected, 1 represents one of the rare examples that show both high storage capacity of C2Hn and good adsorption selectivity of C2Hn/CH4 and CO2/CH4 under ambient conditions, and yet, it has significantly lower energy consumption for regeneration, demonstrating great potential for natural gas purification. More remarkably, submicron-scale 1 (submicro-1) with good crystallinity comprised of sheets with a thickness of ca. 450 nm and length of ca. 2.5 µm was fabricated and then packed into a stainless steel microcolumn as an adsorbent for µ-SPE. Thus, a validated µSPE method for the determination of trace OH-PAHs in complex human urine was developed 4 ACS Paragon Plus Environment

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


with satisfactory sensitivity and good precision by online coupling to liquid chromatographymass spectrometry (LC-MS). Submicro-1 exhibits excellent durability and solvent stability, a long lifetime and biocompatibility. This represents the first example of a mixed-ligand MOF applied as an efficient sorbent for µ-SPE.

Scheme 1. Preparation and potential applications of 1 and submicro-1.

■EXPERIMENTAL SECTION

Synthesis of [Co2(5,4-PMIA)2(TPOM)0.5]·xSolvent (1). A mixture of Co(NO3)2·6H2O (7.3 mg, 0.025 mmol), 5,4-PMIA (6.9 mg, 0.025 mmol), TPOM (11.1 mg, 0.025 mmol), 2 mol/L HCl (1 drop), DMF (2 mL) and H2O (1 mL) was heated in a Teflon-lined stainless vessel (25 cm3) at 120 °C for 2 days, followed by cooling to ambient temperature. The resulting pink crystals of 1 were recovered by filtration (yield: 90% based on Co). Anal. Calcd for evacuated 1 (C81H60Co4N8O24): C, 55.12; H, 3.43; N, 6.35%; found: C, 54.94; H, 3.51; N, 6.26%. IR



Page 6 of 28

spectrum (cm-1): 3455w, 3079w, 2928w, 1670m, 1588w, 1546w, 1451m, 1381m, 1284m, 1211m, 1095m, 1023m, 915s, 778w, 721m, 620s, and 540w. Synthesis of submicron-scale 1 (submicro-1). A mixture of Co(NO3)2·6H2O (55.84 mg, 0.2 mmol), 5,4-PMIA (55.2 mg, 0.2 mmol), and TPOM (88.8 mg, 0.2 mmol) was added to DMF (16 mL) and deionized water (8 mL), which was thoroughly stirred for 10 min at room temperature and heated at 120 °C for another 30 min. The resultant light red products were isolated by centrifugation and then washed with ethanol, followed by drying at 70 °C for 12 h to afford 75 mg of submicro-1. ■ RESULTS AND DISCUSSION

Crystal Structure 1 belongs to the orthorhombic Pbcn space group (Table S1) with two crystallographically independent Co(II) centers, two unique 5,4-PMIA2- anions and half a TPOM ligand in the asymmetric unit. As manifested in Figure 1a, both Co centers lie in a distorted octahedral configuration, surrounded by two N atoms separately from one 5,4-PMIA2- moiety and one TPOM bridge as well as four carboxylate O atoms from three individual 5,4-PMIA2anions, wherein the observed Co–O and Co–N bond lengths vary from 1.993(3) to 2.300(3) Å and from 2.125(4) to 2.166(4) Å, respectively (Table S2). In 1, both 5,4-PMIA2- moieties adopt “Y-shape” coordination fashion with the two carboxylate groups taking different coordination modes (Figure S2a); one binds in a bidentate fashion connecting two individual Co(II) atoms in a syn-syn fashion and the other chelates to one Co(II) atom. In 1, two independent Co(II) atoms are bridged by two carboxylate groups to afford a secondary building unit (SBU) [Co2(COO)2] with a nonbonding Co···Co separation of ca. 6 ACS Paragon Plus Environment

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


4.367 Å. From the topological view,16 it can be seen that each SBU is cross-linked to seven adjacent SBUs to serve as 7-connected node via 5,4-PMIA2- and TPOM struts. Likewise, each 5,4-PMIA2- moiety is fixed to three SBUs to act as a 3-connected node, and each flexible TPOM connects two SBUs, giving a non-interwoven 3D porous architecture with large quadrilateral 1D channels with dimensions of ca. 6.0 × 12.0 Å2 running along b (regardless of the van der Waals radii, Figure 1b and Figure S2b). For clarity, 1 can be simplified as a (3,7)-connected binodal net with a vertex symbol of (46·6)2(44·613·84) (Figure S2c). The void accessible to guest molecules in 1 was estimated to be ∼45% of the total crystal volume (5124/11363 Å3) by the PLATON program.17 Notably, despite no accessible vacant metal sites in the channels, 1 has interior pore walls built with multiple oxygen atoms and phenyl rings from 5,4-PMIA2- moieties and flexible TPOM linkers, offering potential mild specific sites for guest recognitions, which appear to be beneficial in adsorption and separation applications.18

(a)



Page 8 of 28

6.0 × 12.0

(b)

Figure 1. Structure of 1: (a) coordination environment of Co(II); (b) 3D framework with quadrilateral pores along the b axis. The symmetry codes refer to Table S2.

Gas Adsorption and Separation of 1 The characteristic peaks of the fresh sample at ambient temperature are consistent with the simulated PXRD profile from X-ray crystallographic data, demonstrating the good phase purity of bulk 1 (Figure S3). Moreover, 1 is stable and insoluble in common organic solvents (such as benzene, toluene, acetone, n-hexane, THF, DMSO, H2O, butanol, isopropanol, propanol, EtOH, and CH3OH) for at least 72 h at room temperature. Its high crystallinity was retained in a wide pH range from 2−14 for 24 h under ambient conditions. These stabilities were supported by the PXRD patterns (Figure S4). The high chemical stability of 1 could be ascribed to the increased coordination bond strength of Co−N.19 We note that the skeleton of 1 can be stable up to ca. 375 °C under a N2 atmosphere, exhibiting good thermostability as well, as shown by TG (Figure S5). The chemical and thermal stability are prerequisites for the practical applications of natural gas purification and the adsorptive separation of light hydrocarbons. Prior to gas adsorption measurements, the as-synthesized 1 was exchanged with methanol and activated using a supercritical CO2 drying method. The PXRD pattern of the desolvated form 8 ACS Paragon Plus Environment

Page 9 of 28

indicated the preservation of the skeleton after activation (Figure S3). The permanent porosity of desolvated 1 was confirmed by the N2 adsorption isotherm at 77 K, which exhibits a fully reversible type-I behavior, corroborating the microporous nature (Figure 2), with a BrunauerEmmett–Teller (BET) surface area and pore volume of ~920 m2/g and 0.428 cm3/g, respectively. The pore size distributions derived from the N2 isotherms by the nonlocal density functional theory (NLDFT) reveal an average pore size of ca. 1.17 nm in diameter, which matches well with the value from the crystallographic data (ca. 1.2 nm). Overall, the intrinsic permanent porosity together with the good chemical and thermal stability along with the moderate recognition sites within the confined pores of 1 inspired us to investigate its potential gas capture and separation performance.

350 300 1.6

250

1.4 1.2

200

dv(d) (cc nm/g)

3

uptake (cm /g)

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


150 100

1.0 0.8 0.6 0.4 0.2

50

0.0 1.0

0

1.2

1.4

1.6

1.8

pore width (nm)

0

100

200

300

400

500

600

700

800

Pressure (torr) Figure 2. N2 adsorption isotherm of 1 at 77 K. The inset is the pore distribution analysis by the nonlocal density functional theory (NLDFT).



Low-pressure CO2 adsorption isotherms of 1 were recorded at 273, 283 and 300 K (Figure 3). The amount of CO2 uptake by 1 can reach up to 67.3 and 52.8 cm3/g at 273 and 283 K as well as 39.2 cm3/g at 300 K under 1 bar.

70

273 K

60 50

283 K

3

Uptake (cm /g)

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 28

40

300 K 30 20 10 0 0

100

200

300

400

500

600

700

800

Pressure (torr) (a)

(b)

Figure 3. (a) Adsorption isotherms for CO2 at 273, 283 and 300 K for 1. (b) Calculated isosteric heat for CO2 adsorption in 1.

To probe the potential ability of 1 to adsorb light hydrocarbons, single component equilibrium adsorption isotherms for methane and C2Hn were collected at both 273 and 10 ACS Paragon Plus Environment

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


300 K. As expressed in Figure 4a, 1 gives considerably high amounts of C2Hn at 1 bar and 273 K, with uptakes of 150.8 cm3/g for C2H2, 111.0 cm3/g for C2H4, and 115.0 cm3/g for C2H6, but it has a much lower uptake amount of 16.9 cm3/g for CH4. Similarly, at 1 bar and 300 K (Figure 4b), commendable uptakes of C2H2 (95.7 cm3/g), C2H4 (71.3 cm3/g), and C2H6 (81.9 cm3/g) are observed with only a tiny amount of CH4 (12.3 cm3/g) for 1. Importantly, under ambient conditions, the maximum uptakes of C2Hn in 1 are just slightly lower than the benchmark MOFs with open metal sites such as MOF-505 and PCN-16,20 but they are approximately 2-3 times higher than that in the case of SBMOF118 without unsaturated metal sites (uptakes of 30.44, 30.0, and 29.5 cm3/g for C2H2, C2H4, and C2H6, respectively). The uptakes of 1 also exceed those of SBMOF-218 with additional polarizing groups (64.7, 59.8 and 62.2 cm3/g for C2H2, C2H4, and C2H6) and the charged skeleton of FJI-C4 (72.5, 61.4 and 66.3 cm3/g for C2H2, C2H4, and C2H6).21 The remarkable feature is that 1 systematically adsorbs many more C2Hn hydrocarbons than CH4. In addition, the results also demonstrate that 1 is selective toward CO2 over CH4, an indication of its potential for the selective separation of CO2 and C2Hn hydrocarbons over CH4. The separation selectivity of C2Hn/CH4 and CO2/CH4 (equimolar binary mixtures) as a function of pressure was appraised by the ideal adsorbed solution theory (IAST) 22 at 300 K, which was employed to predict multicomponent adsorption behaviors from the experimental pure gas isotherms fitted by the dual site Langmuir Freundlich model (Figure S7).23 On the basis of the component loadings, the adsorption selectivity of the four constituent equimolar binary pairs: C2H6/CH4, C2H4/CH4, C2H2/CH4 and CO2/CH4 were gained. As depicted in Figure 4c, 1 display great separation ratios of C2/C1 at 300 K, with the initial selectivity for C2H6/CH4, C2H4/CH4 and C2H2/CH4 of 34.7, 30.4, and 32.0, 11 ACS Paragon Plus Environment


respectively. Such high selectivities further reveal that 1 exhibits superior separation performance for C2/C1 compared to a number of recently reported MOFs (Table 1) at room temperature, such as LIFM-26,24 JLU-Liu2225 and UTSA-33a.31 Additionally, for 1, the predicted uptake ratio obtained for CO2/CH4 is close to 9 at 300 K under 1 bar, which is comparable

to

those

of

(8.3),26

SNUU-61

JLU-Liu22

(9.4)

and

(Cu2I2)[Cu2(PDC)2(H2O)2]2·[Cu(MeCN)4]I·DMF (PDC = pyridine-3,5-dicarboxylic acid) (9.0)32 as well as higher than those of reported MOFs under similar conditions, such as ZIF-100 (5.9)33 and MOF-177 (4.4).34

140

C2H2

120

C2H4

C2H2 C2H4

80 3

C2H6

100

300 K

CH4

100

273 K

CH4

Uptake (cm /g)

3

Uptake (cm /g)

160

80 60 40

C2H6

60 40 20

20 0

0 0

100

200

300

400

500

600

0

700

100

200

300

400

500

600

700

Pressure (torr)

Pressure (torr)

(a)

(b) 25

100

C2H6 C2H4

20

Qst (KJ/mol)

C2H2

Selectivity

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 28

10 CO2/CH4 C2H6/CH4

15 10

5

C2H4/CH4 C2H2/CH4

1 0

20

40

60

80

100

0

120

0

1

P (kPa)

(c)

2

3

4

5

6

7

Gas uptake (mmol/g)

(d)


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


Figure 4. C2Hn and CH4 sorption isotherms of 1 at 273 K (a) and 300 K (b). (c) IAST-predicted adsorption selectivity of C2Hn/CH4 and CO2/CH4 on 1 at 300 K (C2Hn/CH4 and CO2/CH4 equimolar binary mixtures). (d) Isosteric heats of adsorption for C2Hn in 1. Table 1. Summary of Selectivities of MOFs for Equimolar C2Hn over CH4, as Predicted by IAST. MOF

BET

C2H6/CH4

C2H4/CH4

C2H2/CH4

2

(cm /g)

T

Ref

(K)

920

34.7

30.4

32.0

300

This work

[a]

1513

11

23

/

298

24

JLU-Liu22

1487

14.4

/

/

298

25

ZJU-199

987

/

/

27.3-33.5

296

26

SNUU-61

905.2

/

27.3

14.4

298

27

UTSA-35

742.7

15

8

19

296

28

UTSA-222

703

/

/

18

296

29

690

39.7

22.1

51

298

21

SNUU-23

624.7

/

40

17.4

298

30

UTSA-33a

660

20

12.5

17.1

296

31

195

26

16

18

298

18

1 LIFM-26

FJI-C4

[a]

[a]

SBMOF-2

[a] the selectivity value at 1 bar.

In our opinion, the high uptake of C2Hn and high selectivity of C2Hn/CH4 may originate from two factors, with the first being that the inner walls of 1 are comprised of multiple oxygen atoms, offering available mild adsorption sites for C2Hn through C−H···O interactions and thus further enhancing the host−guest interplay. To understand the adsorption mechanism of C2Hn in 1, we conducted detailed modeling studies by Grand Canonical Monte Carlo (GCMC) simulations using the Sorption module with the COMPASS force field in the Material Studio software. As depicted in Figure 5, in the cavity of 1, each C2H2 molecule is bound through moderate C−H···O (TPOM) hydrogen bonding with H···O distances of 2.699 and 2.702 Å. In contrast, C2H4 shows a weaker binding affinity, as implied by longer hydrogen bonds (H···O, 3.121 and 2.855 Å). The shortest C−H···O lengths between the 13 ACS Paragon Plus Environment


Page 14 of 28

hydrogen atoms of C2H6 and oxygen binding sites of 1 are within 3.082−3.599 Å. Apparently, all of these results from calculations support that the higher C2H2 uptake originates from the stronger binding of C2H2 with the available oxygen atoms of TPOM linkers. The second factor is the higher electrostatic and dispersion interactions of C2Hn gases (Table S3) within the channels, which induce a higher affinity of 1 toward C2Hn gases compared to CH4 with lower polarizability and a smaller kinetic diameter.35 The high selectivity toward CO2 over CH4 for 1 could be traceable to quadrupole−π interactions between absorbed CO2 molecules and the aromatic rings of the pores.36

(a)

(b)

(c)

Figure 5. C2H2 (a), C2H4(b) and C2H6 (c) adsorption sites in 1; the shortest gas-adsorption site distances are calculated from GCMC simulations.


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


To further understand these separation performances, we set out to calculate the isosteric enthalpy of adsorption (Qst) of adsorbate molecules in 1 on the basis of the virial method.37 The Qst value at zero loading for CO2 in 1 is ca. 26 kJ/mol from isotherm data at three different temperatures, 273, 283 and 300 K, which is lower than those of MOFs with no polarizing functional groups or open metal sites, such as SYSU (28.2 kJ/mol).38 The Qst values of C2H2, C2H4 and C2H6 at zero coverage for 1 are ca. 22.2, 21.1 and 22.1 kJ/mol, respectively, as calculated from the fits of their adsorption isotherms at 273 and 300 K (Figure S8), all of which show significant reductions upon gas loading and are lower than those of UTSA-33a31 (ca. 32 kJ/mol for C2Hn) and UTSA-222a29 (26 kJ/mol for C2H2). The values are comparable to that of UTSA-100a39 (22 kJ/mol for C2H2) and are about half the values reported for the MOF-74 series with high densities of open metal sites (41−46 kJ/mol for C2H2).20 It is particularly noteworthy that the lower binding energy of 1 toward C2Hn and CO2 unambiguously indicates the reduced net cost for material regeneration. This feature may be especially beneficial in potential industrial applications, probably because the potentially mild functional sites within 1 could be just right for both adsorption and desorption. Furthermore, the C2Hn adsorption enthalpies lie in the very narrow range, reflecting the negligible impact of the C−C double or triple bonds on the adsorbent−adsorbate interplay. Liquid-Phase Separation of Submicro-1 Strikingly, submicro-1, with good monodispersity and crystallinity, can be facilely achieved. Notably, the PXRD profile of submicro-1 is in good agreement with that of the as-synthesized bulk counterpart, showing that the structural integrity of submicro-1 is maintained (Figure S12). The SEM images of submicro-1 (Figure 6) show that the crystals are comprised of sheets with a 15 ACS Paragon Plus Environment


Page 16 of 28

thickness of ca. 450 nm and length of ca. 2.5 µm. Given the relatively slower diffusion rates of liquid molecules, the smaller thickness of submicro-1 is expected to implement fast kinetics and lower the mass-transfer barriers, thereby, facilitating the resulting liquid-phase separation efficiency. The typical EDX results unambiguously demonstrate that the elements C, N, O and Co are highly dispersed in the whole matrix. For submicro-1, the steep increase in N2 uptake (77 K) at low relative pressure is suggestive of a microporous structure, the pore width of which is still predominately distributed approximately 1.17 nm (NLDFT model), which is consistent with that observed for the bulk counterpart despite the remarkably reduced surface area (~450 m2/g for submicro-1), as depicted in Figure S13. The abundant exposed oxygen sites and phenyl rings in the confined channels make submicro1 an ideal sorbent of µ-SPE for trace OH-PAHs with –OH groups and aromatic conjugated structures. Submicro-1 was packed into a stainless steel microcolumn as an adsorbent for µ-SPE (See Supporting Information S2.1). After selective extraction, the adsorbed analytes were desorbed dynamically and online analyzed by LC-MS (Figure S9). A novel µ-SPE-LC-MS method was developed and applied for the determination of two OH-PAHs in human urine from nonsmoker male residents who live in different ecological environment. The morphology of submicro-1 before and after use for 200 consecutive runs remains almost unaltered, as indicated by the SEM images (Figure S14), revealing the perfect durability. The experimental results also highlight that submicro-1 possessed excellent solvent stability and a long lifetime (Figure S15), even at the high backpressure of 200 bar and with a large volume of mobile phase (approximately 600 mL, flow rate: 0.2 mL/min).


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


Figure 6. SEM images in 10 µm (a) and 1 µm (b) scale bar of submicro-1.

Extraction Selectivity A group of model compounds including several substituted benzenes and OH-PAHs (2-4 condensed rings) was selected to probe the extraction selectivity of submicro-1 with the µ_SPELC-MS system. Enrichment factors (EFs), defined as the ratio of the peak intensity after extraction to that of direct injection, were calculated and are listed in Table 2. It was found that the values of the EFs increase in line with the number of benzene rings (benzene vs. PYR, phenol vs. 2-OH-NAP, 3-OH-PHEN vs. 1-OH-PYR) since more phenyl rings give rise to a higher density of a π electron cloud on conjugated structures and stronger hydrophobicity (Log KOW). Interesting, the EF value of 1-OH-PYR (113) was evidently higher than that of PYR (77), which further implied that submicro-1 exhibited specific recognition toward those analytes containing hydroxyl groups, stemming from the favorable interaction of O−H···O hydrogen bonding between the –OH groups of OH-PAHs and oxygen atoms within the interior walls of 1. Accordingly, it is easy to understand that the interactions between adsorbents and target analytes might originate from π-π stacking and hydrophobic interactions combined with the assistance of O−H···O interactions, which all together aid in the good extraction selectivity. Moreover, submicro-1 shows effective exclusion of proteins (see Supporting Information S2.3), which is mainly ascribed to its molecule sieving effect and is vital for biological analysis. 17 ACS Paragon Plus Environment


Page 18 of 28

Table 2. Adsorption of Model Analytes on Submicro-1. Analyte

Structure

Molecular weight

Molecular size

Log KOWa

EFs

2

(mol/g)

(Å )

Benzene

78

2.8 × 2.4

2.13

19

Aniline

93

4.0 × 2.4

0.90

21

Phenol

94

4.1 × 2.4

1.46

23

2-OH-NAP

144

6.6 × 2.8

2.69

26

3-OH-PHEN

194

7.1 × 3.1

3.86

63

PYR

202

7.0 × 4.8

4.88

77

1-OH-PYR

218

7.0 × 4.8

4.45

113

a

KOW: n-octanol/water partition coefficients. Data were taken from References [40] and [41]. Abbreviations: 2-OH-NAP: 2hydroxynaphthalene; 3-OH-PHEN: 3-hydroxyphenanthren; PYR: pyrene; 1-OH-PYR: 1-hydroxypyrene.

Method evaluation and application The method evaluation of submicro-1-based µ-SPE-LC-MS was carried out systematically under the optimal conditions (Supporting Information S2.2), and relevant parameters are summarized in Table S4. The method possessed satisfactory linearity (n = 7) throughout a wide concentration range of 5-20000 ng/L for 3-OH-PHEN and 10-20000 ng/L for 1-OH-PYR, with excellent correlation coefficients (R2). The detection limits (LOD) were 1.1 ng/L for 3-OHPHEN and 4.1 ng/L for 1-OH-PYR based on a signal-to-noise ratio of 3 (S/N = 3), and their limits of quantification (LOQ) obtained using an S/N = 10 were 5.5 and 14 ng/L, respectively. The reproducibility was investigated by determining the intra-day and inter-day relative standard deviations (RSDs) of standard solutions at three different concentration levels (0.2, 2, and 20 ng/mL). As provided in Table S5, the intra-day RSDs ranged from 1.12 to 8.50%, and the interday RSDs were between 2.6-6.0%. The recoveries of OH-PAHs in urine were assessed by adding a mixed standard solution to three different concentrations of real urine samples collected 18 ACS Paragon Plus Environment

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


from healthy people, and the average recoveries varied in the range of 72-103%. The results serve to illustrate that the submicro-1-based µ-SPE-LC-MS method was sensitive, accurate and reliable. To assess the applicability of the established method, the urine samples of 14 nonsmoking males were analyzed, and typical chromatograms of OH-PAHs in urine samples are presented in Figure 7. The results unveiled that the average concentration of 3-OH-PHEN (0.33 µg/L) in the urine samples of volunteers from Wuhan was markedly higher than those from Enshi (0.19 µg/L), two cities in the Hubei province of China, suggesting that 3-OH-PHEN, as a specific metabolite, may be related to PAH exposure in the ambient air. 42 Additionally, a high detectable proportion of 1-OH-PYR in the urine samples of the Wuhan group was obtained (detection rate 87%), whereas for the Enshi group, the value was only 43%. It is well-known that the industrialized city of Wuhan is supposed to discharge more pollution (such as PAHs) into the environment than the agricultural and tourism city of Enshi.43 Thus, to some extent, a positive correlation between regional environmental contaminations and individual PAH inhalation might be revealed. The proposed method was compared with twelve previously reported methods for the determination of PAHs (with MOFs and conjugated microporous polymers (CMPs) as sorbents) (Table S6).40, 44-54 Our method showed outstanding advantages with regards to the extraction time, linear range and sensitivity. Fast and automated on-line extraction within 2 min meets the requirement of modern analysis; meanwhile, the obtained high EFs toward 3-OH-PHEN vs. 1OH-PYR ensure the sensitivity of the method. Its wide linearity (approximately 4 orders of magnitude) expands its applicability in real sample analysis. The satisfactory enrichment and linearity were attributable to the high surface area and specific recognition sites within submicro19 ACS Paragon Plus Environment


Page 20 of 28

1. Last but not the least, the good durability, as well as excellent water and solvent stability, are some of the desirable features of mixed-ligand submicro-1, in which the bond strengths of Co−N favor the superior chemical stability of the entire framework. In contrast, structure transformation and phase conversion occur when moisture-sensitive MOF-5 (only formed by carboxylate linkers) was applied to extract PAHs in water samples.[50] The results show that submicro-1 possesses great application potential in the determination of trace OH-PAHs in complex urinary samples.

Figure 7. Chromatogram of OH-PAHs in blank and spiked urine samples. Enshi (a) and Wuhan (b), urine sample b spiked with 2 µg/L OH-PAHs (c), and 10 µg/L standard solution (d). Peak identity: (1) 3-OH-PHEN, (2) 1-OH-PYR. The inserted bar chart is the urinary concentration of 3-OH-PHEN in the two cities (Enshi and Wuhan).

■ CONCLUSIONS In summary, 1, possessing both multiple oxygen atoms and phenyl rings from 5,4-PMIA2moieties and flexible TPOM linkers, was designed, which features preferential mild recognition sites desirable for gas storage and separation as well as extraction selectivity toward OH-PAHs. 20 ACS Paragon Plus Environment

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


As a consequence, 1 displays moderately high C2Hn hydrocarbon uptake and good selective capture of C2Hn and CO2 from CH4 under ambient conditions. Given that the binding enthalpies of C2Hn and CO2 are all considerably low, undoubtedly, 1 could be a potential candidate for natural gas purification. Importantly, this work reveals that the incorporation of mild binding sites could be a promising approach to finely tune pore environments in MOFs for enhancing gas adsorption and separation with a lower regeneration energy. In addition, submicro-1 has excellent durability and solvent stability as well as a long lifetime and biocompatibility, and it especially shows excellent extraction selectivity toward 3-OH-PHEN and 1-OH-PYR. Thereby a validated µ-SPE-LC-MS method capable of determining trace OH-PAHs in human urine was established, conferring sensitivity, accuracy and automation advantages. To our knowledge, this work provides the very first study of a mixed-ligand MOF being employed as an efficient sorbent for µ-SPE. Further explorations on new robust MOFs with in-pore functionality for highly selective gaseous and liquid-phase separation applications are ongoing in our lab. ■ ASSOCIATED CONTENT

Supporting Information Additional figures, TGA, PXRD, isotherm fitting, optimization of experimental conditions for liquid-phase separation (PDF) CIF file for 1 (CIF) ■ ACKNOWLEDGMENTS



Page 22 of 28

This work was financially supported by the National Nature Science Foundation of China (Nos. 21771072, 21675058 and 21371065), Self-Determined Research Funds of CCNU from the Colleges’ Basic Research and Operation of MOE (CCNU17QN0020), the Program for Distinguished Young Scientist of Hubei Province (2017CFA075) and the 111 Project (B17019). The work was also partially supported by the US Department of Energy, Office of Basic Energy Sciences, Materials Sciences and Engineering Division under award No. DE-SC0010596 (P. F.). ■ REFERENCES

(1) Zhai, Q. G.; Bu, X. H.; Zhao, X.; Li, D. S.; Feng, P. Y. Pore Space Partition in Metal–Organic Frameworks. Acc. Chem. Res., 2017, 50, 407−417. (2) Tan, Y. X.; Wang, F.; Zhang, J. Design and Synthesis of Multifunctional Metal–Organic Zeolites. Chem. Soc. Rev., 2018, 47, 2130–2144. (3) Duan, J. G.; Higuchi, M.; Horike, S.; Foo, M. L.; Rao, K. P.; Inubushi, Y.; Fukushima, T.; Kitagawa, S. High CO2/CH4 and C2 Hydrocarbons/CH4 Selectivity in a Chemically Robust Porous Coordination Polymer. Adv. Funct. Mater., 2013, 23, 3525−3530. (4) Li, J. R.; Sculley, J.; Zhou, H. C. Metal–Organic Frameworks for Separations. Chem. Rev., 2012, 112, 869−932. (5) Jiang, H. L.; Tatsu, Y.; Lu, Z. H.; Xu, Q. Non-, Micro-, and Mesoporous Metal−Organic Framework Isomers: Reversible Transformation, Fluorescence Sensing, and Large Molecule Separation. J. Am. Chem. Soc., 2010, 132, 5586−5587. (6) Cychosz, K. A.; Ahmad R.; Matzger, A. J. Liquid Phase Separations by Crystalline Microporous Coordination Polymers. Chem. Sci., 2010, 1, 293−302.


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


(7) Wang, F.; Kusaka, S.; Hijikata, Y.; Hosono, N.; Kitagawa, S. Development of a Porous Coordination Polymer with a High Gas Capacity Using a Thiophene-Based Bent Tetracarboxylate Ligand. ACS Appl. Mater. Interfaces, 2017, 9, 33455−33460. (8) McDonald, T. M.; D’Alessandro, D. M.; Krishna, R.; Long, J. R. Enhanced Carbon Dioxide Capture upon Incorporation of N,N'-dimethylethylenediamine in the Metal–Organic Framework CuBTTri. Chem. Sci. 2011, 2, 2022−2028. (9) Cao, C.; Chung, T.-S.; Liu, Y.; Wang, R.; Pramoda, K. Chemical Cross-Linking Modification of 6FDA2,6-DAT Hollow Fiber Membranes for Natural Gas Separation. J. Membr. Sci., 2003, 216, 257−268. (10) Easun, T. L.; Moreau, F.; Yan, Y.; Yang S. H.; Schröder, M. Structural and Dynamic Studies of Substrate Binding in Porous Metal–Organic Frameworks. Chem. Soc. Rev., 2017, 46, 239−274. (11) Demessence, A.; D’Alessandro, D. M.; Foo, M. L.; Long, J. R. Strong CO2 Binding in a WaterStable, Triazolate-Bridged Metal−Organic Framework Functionalized with Ethylenediamine. J. Am. Chem. Soc., 2009, 131, 8784−8786. (12) Yuan, J.-M.; Butler, L. M.; Gao, Y. T.; Murphy, S. E.; Carmella, S. G.; Wang, R.; Nelson, H. H.; Hecht, S. S. Urinary Metabolites of a Polycyclic Aromatic Hydrocarbon and Volatile Organic Compounds in Relation to Lung Cancer Development in Lifelong Never Smokers in the Shanghai Cohort Study. Carcinogenesis, 2013, 35, 339−345. (13) Campo, L.; Rossella, F.; Fustinoni, S. Development of a Gas Chromatography/Mass Spectrometry Method to Quantify Several Urinary Monohydroxy Metabolites of Polycyclic Aromatic Hydrocarbons in Occupationally Exposed Subjects. J. Chromatogr. B, 2008, 875, 531−540. (14) Sajid, M. Porous Membrane Protected Micro-Solid-Phase Extraction: A Review of Features, Advancements and Applications. Anal. Chim. Acta, 2017, 965, 36−53. (15) Wang, Y. H.; Jin, S. G.; Wang, Q. Y.; Lu, G. H.; Jiang, J. J.; Zhu, D. R. Zeolitic Imidazolate Framework-8 as Sorbent of Micro-Solid-Phase Extraction to Determine Estrogens in Environmental Water Samples. J. Chromatogr. A, 2013, 1291, 27−32. (16) Blatov, V. A.; Proserpio, D. M. Topological Relations between Three-Dimensional Periodic Nets. I. Uninodal nets. Acta Crystallogr., Sect. A: Found. Crystallogr., 2009, 63, 329−343.



Page 24 of 28

(17) Spek, A. L. Single-Crystal Structure Validation with the Program PLATON. J. Appl. Crystallogr., 2003, 36, 7−13. (18) Parise, J. B.; Li, J.; Plonka, A. M.; Han, Y.; Woerner, W. R.; Banerjee, D.; Dong, X. L.; Krishna, R.; Wang H.; Chen, X. Y. Light Hydrocarbon Adsorption Mechanisms in Two Calcium-Based Microporous Metal Organic Frameworks. Chem. Mater., 2016, 28, 1636−1346. (19) Zhang, J. P.; Zhang, Y. B.; Lin, J. B.; Chen, X. M. Metal Azolate Frameworks: From Crystal Engineering to Functional Materials. Chem. Rev., 2012, 112, 1001−1033. (20) He, Y. B.; Krishna R.; Chen, B. L. Metal–Organic Frameworks with Potential for EnergyEfficient Adsorptive Separation of Light Hydrocarbons. Energy Environ. Sci., 2012, 5, 9107−9120. (21) Li, L.; Wang, X. S.; Liang, J.; Huang, Y. B.; Li, H. F.; Lin, Z. J.; Cao, R. Water-Stable Anionic Metal−Organic Framework for Highly Selective Separation of Methane from Natural Gas and Pyrolysis Gas. ACS Appl. Mater. Interfaces, 2016, 8, 9777−9781. (22) Myers A. L.; Prausnitz, J. M. Thermodynamics of Mixed-Gas Adsorption. AIChE J., 1965, 11, 121−127. (23) Bae, Y.-S.; Mulfort, K. L.; Frost, H.; Ryan, P.; Punnathanam, S.; Broadbelt, L. J.; Hupp, J. T.; Snurr, R. Q. Separation of CO2 from CH4 Using Mixed-Ligand Metal−Organic Frameworks. Langmuir, 2008, 24, 8592−8598. (24) Chen, C. X.; Zheng, S. P.; Wei, Z. W.; Cao, C. C.; Wang, H. P.; Wang, D. W.; Jiang, J. J.; Fenske, D.; Su, C. Y. A Robust Metal–Organic Framework Combining Open Metal Sites and Polar Groups for Methane Purification and CO2/Fluorocarbon Capture. Chem. Eur. J., 2017, 23, 4060−4064. (25) Wang, D. M.; Liu, B.; Yao, S.; Wang, T.; Li, G. H.; Huo, Q. S.; Liu, Y. L. A Polyhedral Metal– Organic Framework Based on the Supermolecular Building Block Strategy Exhibiting High Performance for Carbon Dioxide Capture and Separation of Light Hydrocarbons. Chem. Commun., 2015, 51, 15287−15289. (26) Zhang, L.; Zou, C.; Zhao, M.; Jiang, K.; Lin, R. B.; He, Y. B.; Wu, C. D.; Cui, Y. J.; Chen, B. L.; Qian, G. D. Doubly Interpenetrated Metal–Organic Framework for Highly Selective C2H2/CH4 and C2H2/CO2 Separation at Room Temperature. Cryst. Growth Des., 2016, 16, 7194−7197.


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


(27) Zhang, J. W.; Hu, M. C.; Li, S. N.; Jiang, Y. C.; Zhai, Q. G. Ligand Torsion Triggered Two Robust Fe-Tetratopic Carboxylate Frameworks with Enhanced Gas Uptake and Separation Performance. Chem. Eur. J., 2017, 23, 6693−6700. (28) He, Y. B.; Zhang, Z. J.; Xiang, S. C.; Fronczek, F. R.; Krishna, R.; Chen, B. L. A Robust Doubly Interpenetrated Metal–Organic Framework Constructed from a Novel Aromatic Tricarboxylate for Highly Selective Separation of Small Hydrocarbons. Chem. Commun., 2012, 48, 6493−6495. (29) Ma, X.; Guo, J. R.; Wang, H. L.; Li, B.; Yang, T. L.; Chen, B. L. Microporous Lanthanide Metal– Organic Framework Constructed from Lanthanide Metalloligand for Selective Separation of C2H2/CO2 and C2H2/CH4 at Room Temperature. Inorg. Chem., 2017, 56, 7145−7150. (30) Zhang, J. W.; Hu, M. C.; Li, S. N.; Jiang, Y. C.; Zhai, Q. G. Microporous Rod Metal–Organic Frameworks with Diverse Zn/Cd–Triazolate Ribbons as Secondary Building Units for CO2 Uptake and Selective Adsorption of Hydrocarbons. Dalton Trans., 2017, 46, 836−844. (31) He, Y. B.; Zhang, Z. J.; Xiang, S. C.; Fronczek, F. R.; Krishna R.; Chen, B. L. A Microporous Metal–Organic Framework for Highly Selective Separation of Acetylene, Ethylene, and Ethane from Methane at Room Temperature. Chem. - Eur. J., 2012, 18, 613−619. (32) He, H. M.; Sun, F. X.; Ma, S. Q.; Zhu, G. S. Reticular Synthesis of a Series of HKUST-like MOFs with Carbon Dioxide Capture and Separation. Inorg. Chem., 2016, 55, 9071−9076. (33) Wang, B.; Côté, A. P.; Furukawa, H.; O’Keeffe M.; Yaghi, O. M. Colossal Cages in Zeolitic Imidazolate Frameworks as Selective Carbon Dioxide Reservoirs. Nature, 2008, 453, 207−211. (34) Saha, D.; Bao, Z.; Jia, F.; Deng, S. Adsorption of CO2, CH4, N2O, and N2 on MOF-5, MOF-177, and Zeolite 5A. Environ. Sci. Technol., 2010, 44, 1820−1826. (35) Herm, Z. R.; Bloch, E. D.; Long, J. R. Hydrocarbon Separations in Metal–Organic Frameworks. Chem. Mater., 2014, 26, 323−338. (36) Plonka, A. M.; Banerjee, D.; Woerner, W. R.; Zhang, Z.; Nijem, N.; Chabal, Y. J.; Li, J.; Parise, J. B. Mechanism of Carbon Dioxide Adsorption in a Highly Selective Coordination Network Supported by Direct Structural Evidence. Angew. Chem., Int. Ed., 2013, 52, 1692−1695.



Page 26 of 28

(37) Rowsell J. L. C.; Yaghi, O. M. Effects of Functionalization, Catenation, and Variation of the Metal Oxide and Organic Linking Units on the Low-Pressure Hydrogen Adsorption Properties of Metal−Organic Frameworks. J. Am. Chem. Soc., 2006, 128, 1304−1315. (38) Xiang, S. L.; Huang, J.; Li, L.; Zhang, J. Y.; Jiang, L. X.; Kuang, J. C.; Su, C. Y. Nanotubular Metal−Organic Frameworks with High Porosity Based on T-Shaped Pyridyl Dicarboxylate Ligands. Inorg. Chem., 2011, 50, 1743−1748. (39) Hu, T. L.; Wang, H. T.; Li, B.; Krishna, R.; Wu, H.; Zhou, W.; Zhao, Y. F.; Han, Y.; Wang, X.; Zhu, W. D.; Yao, Z. Z.; Xiang, S. C.; Chen, B. L. Microporous Metal–Organic Framework with Dual Functionalities for Highly Efficient Removal of Acetylene from Ethylene/Acetylene Mixtures. Nat. Commun., 2015, 6, 7328. (40) Zhou, L. J.; Hu, Y. L.; G. K. Li. Conjugated Microporous Polymers with Built-In Magnetic Nanoparticles for Excellent Enrichment of Trace Hydroxylated Polycyclic Aromatic Hydrocarbons in Human Urine. Anal. Chem., 2016, 88, 6930−6938. (41) Schnackenberg, L. K.; Beger, R. D. Whole-Molecule Calculation of Log P Based on Molar Volume, Hydrogen Bonds, and Simulated 13C NMR Spectra. J. Chem. Inf. Model., 2005, 45, 360−365. (42) Wang, S. L.; Xu, H. Inorganic–Organic Hybrid Coating Material for the Online in-Tube Solid-Phase Microextraction of Monohydroxy Polycyclic Aromatic Hydrocarbons in Urine. J. Sep. Sci., 2016, 39, 4610−4620. (43) Grainger, J.; Huang, W.; Patterson Jr., D. G.; Turner, W. E.; Pirkle, J.; Caudill, S. P.; Wang, R. Y.; Needham, L. L.; Sampson, E. J. Reference Range Levels of Polycyclic Aromatic Hydrocarbons in the US Population by Measurement of Urinary Mono-Hydroxy Metabolites. Environmental Research, 2006, 100, 394−423. (44) Zhou, Y. Y.; Yan, X. P.; Kim, K. N.; Wang, S. W.; Liu, M. G. Exploration of Coordination Polymer as Sorbent for Flow Injection Solid-Phase Extraction on-Line Coupled with High-Performance Liquid Chromatography for Determination of Polycyclic Aromatic Hydrocarbons in Environmental Materials. J. Chromatogr. A, 2006, 1116, 172−178.


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


(45) Zhang, G. J.; Zang, X. H.; Li, Z.; Wang, C.; Wang, Z. Polydimethylsiloxane/Metal-Organic Frameworks Coated Fiber for Solid-Phase Microextraction of Polycyclic Aromatic Hydrocarbons in River and Lake Water Samples. Talanta, 2014, 129, 600−605. (46) Zhou, Q. X.; Lei, M.; Li, J.; Liu, Y. L.; Zhao, K. F.; Zhao, D. C. Magnetic Solid Phase Extraction of N- and S-containing Polycyclic Aromatic Hydrocarbons at ppb Levels by Using a Zerovalent Iron Nanoscale Material Modified with a Metal Organic Framework of Type Fe@MOF-5, and Their Determination by HPLC. Microchim. Acta, 2017, 184, 1029−1036. (47) Huo, S. H.; Yan, X. P. Facile Magnetization of Metal–Organic Framework MIL-101 for Magnetic Solid-Phase Extraction of Polycyclic Aromatic Hydrocarbons in Environmental Water Samples. Analyst, 2012, 137, 3445–3451. (48) Du, F.; Qin, Q.; Deng, J.; Ruan, G.; Yang, X.; Li, L.; Li, J. Magnetic Metal–Organic Framework MIL-100(Fe) Microspheres for the Magnetic Solid-Phase Extraction of Trace Polycyclic Aromatic Hydrocarbons from Water Samples. J. Sep. Sci., 2016, 39, 2356–2364. (49) Rocío-Bautista, P.; Pinoa, V.; Ayalaa, J. H.; Pasánb, J.; Ruiz-Pérezb C.; Afonso, A. M. A MagneticBased Dispersive Micro-Solid-Phase Extraction Method Using the Metal-Organic Framework HKUST-1 and Ultra-High-Performance Liquid Chromatography with Fluorescence Detection for Determining Polycyclic Aromatic Hydrocarbons in Waters and Fruit Tea Infusions. J. Chromatogr. A, 2016, 1436, 42–50. (50) Yang, S.; Chen, C.; Yan, Z.; Cai, Q.; Yao, S. Evaluation of Metal-Organic Framework 5 as a New SPE Material for the Determination of Polycyclic Aromatic Hydrocarbons in Environmental Waters. J. Sep. Sci., 2013, 36, 1283–1290. (51) Hu, Y. L.; Huang, Z. L.; Liao, J.; Li, G. K. Chemical Bonding Approach for Fabrication of Hybrid Magnetic Metal−Organic Framework-5: High Efficient Adsorbents for Magnetic Enrichment of Trace Analytes. Anal. Chem., 2013, 85, 6885−6893. (52) Wei, S.; Lin, W.; Xu, J.; Wang, Y.; Liu, S.; Zhu, F.; Liu, Y.; Ouyang, G. Fabrication of a Polymeric Composite Incorporating Metal-Organic Framework Nanosheets for Solid-Phase Microextraction of Polycyclic Aromatic Hydrocarbons from Water Samples. Anal. Chim. Acta, 2017, 971, 48−54.



Page 28 of 28

(53) Chen, X. F.; Zang, H.; Wang, X.; Cheng, J. G.; Zhao, R. S.; Cheng, C. G.; Lu, X. G. Metal–Organic Framework MIL-53(Al) as a Solid-Phase Microextraction Adsorbent for the Determination of 16 Polycyclic Aromatic Hydrocarbons in Water Samples by Gas Chromatography–Tandem Mass Spectrometry. Analyst, 2012, 137, 5411–5419. (54) Li, Q. L.; Xia, W.; Chen, X. F.; Wang, M. L.; Zhao, R. S. In Situ Hydrothermal Growth of Ytterbium-Based Metal–Organic Framework on Stainless Steel Wire for Solid-Phase Microextraction of Polycyclic Aromatic Hydrocarbons from Environmental Samples. J. Chromatogr. A, 2015, 1415, 11–19.

Table of Contents


Highly Selective Gaseous and Liquid-Phase Separation over a Novel

Recommend Documents