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Synthesis, Photoluminescence and Gas Adsorption Properties of a New Furan-Functionalized MOF and Direct Carbonization for Synthesis of Porous Carbon Jun Zhang, Wenbin Yang, Xiaoyuan Wu, Lei Zhang, and Can-Zhong Lu Cryst. Growth Des., Just Accepted Manuscript • DOI: 10.1021/acs.cgd.5b01481 • Publication Date (Web): 08 Dec 2015 Downloaded from http://pubs.acs.org on December 9, 2015

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Crystal Growth & Design

1

Synthesis, Photoluminescence and Gas Adsorption Properties of

2

a New Furan-Functionalized MOF and Direct Carbonization for

3

Synthesis of Porous Carbon

4

Jun Zhang

5

†Key Laboratory of Design and Assembly of Functional Nanostructures, Fujian

6

Institute of Research on the Structure of Matter, Chinese Academy of Sciences

7

Fuzhou, Fujian 350002, P.R. China

8

‡Fujian Provincial Key Laboratory of Nanomaterials, Fujian Institute of Research on

9

the Structure of Matter, Chinese Academy of Sciences

†,‡,§

†

†

†

†

, Wenbin Yang ,‡, Xiao-Yuan Wu ,‡, Lei Zhang ,‡, and Can-Zhong Lu*, , ‡

10

§University of Chinese Academy of Sciences Beijing, 100049, P.R. China

11

ABSTRACT

12

A new 3D zinc-organic framework of [ZnL]·5H2O (1, K2L = potassium

13

4'-furyl-2,2':6',2"-terpyridine-4,4"-dicarboxylate)

14

hydrothermal conditions. Complex 1 possesses a 3D two-fold interpenetrated

15

4-connected sra network with pores decorated by non-coordination furan rings, and

16

exhibits a broad blue luminescence emission band peaked at 450 nm. Due to the

17

chelating effect of trepyridyl moieties in L2- ligands and the absence of solvent

18

coordination sites on Zn(II), complex 1 exhibits a good thermal and acid-proof

19

stability, and can be directly carbonized at 1000 oC under argon atmosphere into a

20

new microporous carbon material C1000. The gas adsorption properties of desolvated

21

1a and microporous carbon C1000 have been studied by N2 and CO2 sorption

22

measurements.

has

been

synthesized

under

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INTRODUCTION

24

Metal-organic frameworks (MOFs) are a family of porous crystalline materials

25

assembled from metal centers/clusters and organic linkers.1-3 The recent decade has

26

witnessed a continuous and fast development in the research on MOFs due to their

27

structural versatility and chemical nature tunability. In particular, owing to their

28

exceptionally high surface areas and adjustable pore structures, MOFs have been

29

extensively noted as promising porous materials that can be effectively tailored to

30

specific functional applications, such as gas storage and separation,4, 5 catalysis,6, 7

31

proton conductors,8,

32

recently, considerable attention has been paid to the task-specific design and pore

33

surface decoration of MOFs with intriguing architectures and multifunctional

34

properties.15 In comparison with other types of porous materials, such as zeolites and

35

activated carbons, MOFs display many advantages (i. e. high surface area and pore

36

volume, structural tunability and functionalization, and easy synthesis). However, the

37

inherent drawbacks of relatively low thermal and chemical stability for most of MOFs

38

restrict their large-scale applications in practice and developments in industries.1, 3

39

Thermally, MOFs usually can stabilize up to 250 oC beyond which the framework

40

starts to collapse or decompose.16 Otherwise, most MOFs are sensitive to moisture,

41

especially in an acidic or basic medium; MOFs are poorly chemical resistant. Up to

42

date, only a few MOFs show high thermal and chemical stabilities.17, 18 Therefore, the

43

design and synthesis of MOFs with ultrahigh thermal and chemical stability is still

44

challengeable for chemists, but indispensible for practical applications.

9

luminescent sensing materials,10-12 drug delivery.13,

14

More

45

Very recently, MOFs with high thermal stability have been demonstrated as

46

attractive templates to prepare various porous carbon materials19-21 applied extensively

47

in odor absorbers, batteries, supercapacitors and full cells.22 By this pathway, the

48

carbonization of carbon sources (such as furfuryl alcohol) occurs in the pores of

49

MOFs.23 However, owing to the large carbon content of origin components in MOFs, 2 ACS Paragon Plus Environment

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it may not be always necessary for introducing additional carbon sources as additives,

51

and MOFs can be carbonized directly in an inert atmosphere to form microporous or

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nanoporous carbons. Comparing with the traditional methods (i. e. activation of

53

precursors and carbonization of polymer aerogels) for preparing porous carbon

54

materials, the above synthetic pathways using MOFs can produce uniformed porous

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carbons with high surface areas and high adsorption capacity, and therefore promote

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the practical applications of such materials in H2 storage, CO2 uptake and

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supercapacitor.24

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It is well-known that the instability of MOFs is mostly caused by the change

59

of metal coordination geometry through loss of coordinated solvent molecules during

60

desolvation. One of possible solutions25-27 to this problem is to use multidentate

61

chelating ligands. In [Zn2(bptc)]·4H2O,27 the bptc4- ligand forms two very stable

62

tridentate chelating synthon with metal ions via two carboxylate O and one N donor,

63

and the donor atoms on the ligand occupy all the coordination sites of Zn(II). As a

64

result, the open framework of [Zn2(bptc)] can be stable up to 450oC, and only

65

decomposes in strong acid (e. g. pH < 2) or strong base (pH > 14) media. Our own

66

recent work has focused on the use of polytopic hetero-functional ligands to construct

67

unusual coordination polymers or MOFs.28 Herein, we report a new framework

68

material

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4'-furyl-2,2':6',2"-terpyridine-4,4"-dicarboxylate (L2-, see Scheme 1). In this

70

multidenate hetero-functional ligand, there is one very stable N-N-N tridentate

71

chelating synthon with metal ions, while the two carboxylates can easily compete

72

with solvent molecules to fulfill the metal coordination geometry, and the furyl

73

moiety can serve as a non-coordination functional group dangling in the pores of

74

framework. As expected, the resulting framework material shows ultrahigh stability

75

(up to 450oC), especially in strong acidic aqueous media (e. g. aqueous HCl with pH

76

= 1), and reversibly absorbs gas molecules into the framework pores. Interestingly,

77

direct carbonization of 1 under argon atmosphere at 1000oC generates porous carbon

[Zn(L)]·5H2O

(1)

based

on

Zn(II)

bound

to

anionic



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C1000. Comparing with 1, although C1000 has a lower surface area, it shows a good

79

CO2 uptake capacity.

80

EXPERIMENTAL SECTION

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All of the regents not specifically listed below were obtained from commercial

82

sources

and

83

4'-furyl-2,2':6',2"-terpyridine-4,4"-dicarboxylic acid (K2L, Scheme 1) was prepared

84

according

85

for C, H, and N were performed on an EA1110 CHNS-0 CE elemental analyzer. The

86

IR spectra were recorded on KBr pellets 4000-500 cm-1 using a PECO (U.S.A.)

87

Spectrum One FT-IR spectrophotometer. Thermal stability studies were carried out on

88

a TGA/DSC 1 STARe system at a heating rate of 10 °C/min, from 35°C to 1000°C

89

under N2 atmosphere. Power X-ray diffraction (PXRD) patterns were measured on a

90

Rigaku Miniflex2 diffractometer with Cu-Kα radiation (λ=1.54056 Å). Fluorescence

91

spectroscopy data were recorded on a FLS920 fluorescence spectrophotometer. Gas

92

adsorption measurements were performed on the ASAP (Accelerated Surface Area

93

and Porosimetry) 2020 System. Scanning electron microscopy (SEM) was performed

94

on a Hitachi SU8010. High-resolution transmission electron microscopy (HR-TEM)

95

images were taken on an FEI Tecnai F20. Raman spectra were obtained using a

96

Renishaw UV-1000 Photon Design spectrometer at 532 nm excitation focused

97

through at 100 × microscope objective for a total interrogation spot size of ~ 1 µm.

98

Scheme 1. Structure of L2-

to

used

the

as

procedure

received.

described

The

potassium

salt

of

previously.29 The elemental analysis

99


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Synthesis of [ZnL]·5H2O (1). In a typical run, Zn(CH3COO)2·2H2O (0.044 g, 0.2

101

mmol), K2L (0.047 g, 0.1 mmol) and CH3COOH (2.0 ml) were stirred in H2O (10.0

102

ml) and sealed in a stainless steel autoclave with a Teflon-liner. The reaction mixture

103

was heated at 180 °C for 120 hours, and then slowly cooled to room temperature,

104

resulting in brown crystals of 1, which were washed several times with H2O, filtered

105

and dried. The yield of the reaction was 42%, based on Zn2+. Elemental analysis calcd

106

(%) for 1 (C21H21N3O10Zn): C 46.64, H 3.91, N 7.77; found: C 47.08, H 3.88, N 7.62;

107

Selected IR (KBr, cm−1): 3410 (br), 1608(s), 1551(s),1482(m), 1456(w) 1363(s),

108

1237(m), 1012(m), 871 (m), 778 (m), 700 (s).

109

Preparation of C1000. The carbonization of as-synthesized 1 was performed under a

110

argon flow at a heating rate of 10°C min-1 up to 1000 oC, kept at this temperature for 8

111

h, and then slowly cooled to room temperature. The obtained carbon materials were

112

herein designated as C1000.

113

X-ray Crystallography. Diffraction data of 1 were collected at 293 K on a

114

SuperNova Atlas diffractometer equipped with graphite-monochromated Cu-Kα

115

radiation (λ =1.54184 Å). The structure was solved by direct methods, and refined by

116

full-matrix least-squares methods with SHELXL-97 program package.30 All ordered

117

non-hydrogen atoms were refined anisotropically, and hydrogen atoms were placed

118

geometrically and refined with a riding model. One of two non-coordination furan

119

rings was modulated in disorder along the axis defined by the C-C bond between

120

furan ring and the central pyridine ring. The highly disordered guest solvents could

121

not be well modeled in the refinement, so they were removed by using the SQUEEZE

122

option in PLATON. 31 The diffuse electron density in the pore cavities, calculated

123

from SQUEEZE, was at 709 electrons per unit cell, corresponding to ca. 5H2O per

124

[ZnL], which has been confirmed by elemental analysis and TGA. Details for

125

structural analysis are summarized in Table S1.

126 5 ACS Paragon Plus Environment


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RESULTS AND DISCUSSION

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Synthesis and Structural Characterization. The hydrothermal reaction of

129

Zn(CH3COO)2·2H2O with K2L using CH3COOH to adjust pH = 2 at 180 °C for 72

130

hours afford a pure phase of brown block crystals of 1 (42% yield). A series of

131

experimental parameters, such as the reaction time, temperature, solvent and pH, were

132

tested for the formation of the resultant MOF. It was found that in all these factors the

133

pH value (adjusted with acetic acid) play the most important role in affecting the

134

quality of the final crystallized product. The pH value must be adjusted to 2.0 to

135

obtain pure crystalline products.

136

Compound 1 crystallizes in the orthorhombic Pnaa space group, with the

137

asymmetric unit consisting of two Zn2+ ions, two ligands L2−, and shows a new type

138

of two-fold interpenetrated three-dimensional (3D) framework constructed from Zn(II)

139

ions and anionic ligands L2-. Each Zn(1) or Zn(2) ion is coordinated by a tridendate

140

chelating array comprising three pyridyl N-donors all from the same terpyridyl moiety

141

of a L2- ligand, Figure 1a.

142

completed by two carboxylate oxygen atoms, O(7A) and O(9B) from two adjacent L2-

143

ligands, affording a distorted trigonal bipyramidal configuration with the

144

O(7A)-Zn(1)-O(9B) bond angle of 124.09(16)o and the two coordination planes

145

( O(7A)-Zn1-O(9B)-N2 and N1-Zn1-N3 in Figure 1a ) almost perpendicular to each

146

other (dihedral angle 83.991(2)o). The Zn(2) ion is further bound to three carboxylate

147

O atoms from two different L2- ligands, giving O(2C)-Zn(2)-O(3), O(2C)-Zn(2)-O(4)

148

and O(3)-Zn(2)-O(4) bond angles of 93.87(18), 151.2(2) and 57.38(19)o, respectively,

149

with the two coordination planes ( O(2C)-Zn(2)-O(3)-O(4)-N(5) and N(4)-Zn(2)-N(6)

150

in Figure 1a ) almost perpendicular to each other by symmetry ( dihedral angle

151

89.568(1)o ). Therefore, the Zn(2) ion adopts a distorted octahedral coordination

152

geometry. Both Zn-N [2.071(4) – 2.145(3) Å)] and Zn-O bond distances [1.957(3) to

The remaining two coordination sites of the Zn(1) ion are


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153

2.314(5) Å, see Table S2] are in the normal ranges compared to reported for Zn-O

154

bond lengths found in MOFs.32

155 156

Figure 1. Crystal structure of 1. (a) coordination geometries of Zn(II) and linking modes of L2- ligands

157

(symmetric modes: A, 1-x, -0.5+y, 0.5+z; B, 1-x, -0.5+y, -0.5+z; C, 0.5+x, 0.5-y, z; D, 1-x, 0.5+y,

158

-0.5+z, E, 1-x, 0.5+y, 0.5+z; F, -0.5+x, 0.5-y, z); (b) A schematic view of the polyhedral cage

159

[Zn(1)N3O2] and [Zn(2)N3O3] polyhedra are highlighted in green and turquoise, respectively. The

160

purple bold sticks between Zn(II) centers represent the linkage via pyrindyl-4-carboxylate moieties in

161

L2- ligands); (c) and (d) views of the 3D framework, along the b and c axis, respectively (the

162

non-coordination furan rings are highlighted in spacing mode).

163

In 1, there are two crystallographically independent L2- ligands sustaining the

164

3D framework through different linkages. The first one is almost co-planar, 7 ACS Paragon Plus Environment


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completely parallel to the ab plane, only chelated to the Zn(1) centre via the terpyridyl

166

moiety, and links two Zn(2) ions via carboxylate groups along the a axis of the unit

167

cell; the other is only chelated to the Zn(2) centre via the terpyridyl moiety, and links

168

two Zn(1) ions via carboxylate groups along the c axis of the unit cell. Such linkages

169

result in the formation of a 3D 4-connected sra-type framework (Figure 1c and 1d)

170

with 42.63.8 topology (Figure 2a and Figure S3),33 in which both Zn(1) and Zn(2)

171

centers act as a 4-connecting node, while the pyridyl-4-carboxylate moieties in L2-

172

ligands essentially serve as the linkers between Zn(1) and Zn(2) nodes (Figure 1b).

173

Interestingly, seven Zn(1) and seven Zn(2) centers are alternately bonded by 17

174

pyridyl-4-carboxylate moieties in L2- ligands to form a large irregular polyhedral cage

175

with cavity diameter of ca.10 Å (Figure 1b and Figure S1). Thus, the overall

176

framework of 1 can also be viewed as the closed packing of the irregular polyhedral

177

cages. Meanwhile, 1 shows interconnected channels along all three crystallographic

178

axes. However, both the irregularly hexagonal channels along the a axis (Figure S2a)

179

and the octagonal channels along the c axis (Figure 1d) are split and partly blocked by

180

non-coordination furan rings. The approximate dimension of the square channels

181

(Figure 1c) along the b axis is ca. 8 Å×8 Å, and is defined by the span of the

182

pyridyl-4-carboxylate linker of the bridging ligands. Upon two-fold interpenetration,

183

the square channels are divided into two types of smaller rectangular channels. If

184

considering the van der Waals radius of the nearest atoms, at least one type of

185

rectangular channels are too narrow to allow any solvent molecules to pass the

186

channels, which is clearly shown in the space-filling mode of Figure 2b. However, 1

187

still possesses effective 1D channel when viewed along the c axis (Figure 2c). In fact,

188

the solvent-accessible void for 1 was estimated using software PLATON to be 29.3%

189

of the unit cell volume, and the porosity of desolvated 1a has been confirmed by the

190

adsorption of N2 and CO2.


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191 192

Figure 2. (a) the sra 42.63.8 network for 1 (Zn(1) and Zn(2) nodes highlighted in red and blue balls,

193

respectively). (b) and (c) the space-filling

194

viewed along b and c axis, respectively.

195

Thermal and Chemical Stabilities of 1. Remarkably, complex 1 possesses not only

196

open channels decorated with non-coordination furan groups, but also high thermal

197

and acid-proof stability relative to most of known MOFs.34 The thermal stability of 1

198

has been evaluated in the temperature range of 35 – 1000 oC under an N2 stream

199

(Supporting Information, Figure S5). TGA curve of 1 exhibits an initial weight loss of

200

16.1% from 35 to 150 oC, corresponding to the release of trapped molecules in pores

201

(calcd 16.6%), and followed by a relative steady plateau until 450 oC, beyond which

202

the framework of 1 starts to decompose. The crystalline phase purity of 1 was

203

confirmed by comparing experimental PXRD patterns with the simulated one from

204

single-crystal data. As shown in Figure 3a, although some diffraction peaks become

205

weaker along with the increase of acidity, the powder X-ray diffraction (PXRD)

206

patterns of 1 remain almost intact upon immersion in aqueous HCl solutions with

207

different pH values from 0.2 to 7 for 5 days, suggesting that no phase transition or

208

framework collapse occurs upon treatments in acidic aqueous solution. However,

209

complex 1 is unstable in basic solutions. To further evaluate the chemical stability of

210

1 in strong acid solution, as-synthesized samples were soaked in aqueous HCl

211

solution at pH=1 for different times. Strikingly, the results, as shown in Figure 3b,

212

indicated that 1 has good acid resistance even after 30 days. Due to the chelating

213

effect of trepyridyl moieties in L2- ligands and the absence of solvent coordination

mode of the two-fold interpenetrated structure

for 1,



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214

sites on Zn(II), the coordination bonds, as well as the whole framework of 1,

215

become highly resistant to the attack of water and even acid. However, in basic

216

aqueous solutions the strong coordinating ability of hydroxyl ions gradually results in

217

the collapse of framework.

218 219

Figure 3. (a) pH-dependant PXRD patterns of 1 at room temperature. (b) Time-dependant PXRD

220

patterns of 1 immersed in pH = 1 HCl solution.

221

Luminescent Properties of 1. Luminescent MOFs have been extensively

222

investigated owing to their potential applications in chemical sensors, photochemistry,

223

electroluminescent devices, and so on.35 The luminescent property of 1 was

224

investigated in the solid state at room temperature. Upon photo excitation at 370 nm,

225

complex 1 displays a broad blue luminescence emission band peaked at 450 nm

226

(Figure 4). In comparison to the emission peak at 460 nm (λex = 370 nm) of the salt of

227

ligand K2L, the maximum emission of 1 does not exhibit a significant shift, while, its

228

luminescent strength increases notably. The Zn(II) ion has a d10 configuration, which

229

is difficult to oxidize or reduce, and as a result, metal-to-ligand charge transfer

230

(MLCT) or ligand-to-metal charge transfer (LMCT) will not occur in emission.

231

Therefore, the luminescent emission band of 1 can be assigned to the intraligand

232

emission, and the luminescent enhancing is attributed to the coordination bonds


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233

between the Zn2+ and the ligand, which adjust the conformational rigidity of ligands

234

and cause the decrease of non-radiation transition.36

235 236

Figure 4. Solid-state emission spectra for the K2L ligand and complex 1.

237

Microporous carbon C1000 prepared by direct carbonization of 1. Recently, high

238

thermal and chemical stable MOFs, such as MOF-5, Al-PCP, and ZIF-8, have been

239

extensively roasted in the presence of additional carbon sources (such as furfuryl

240

alcohol) to prepare porous carbons.37 Hu and co-workers carried out a systematic

241

investigation about the thermal decomposition of MOF-5. Through focusing on the

242

characteristics of decomposed products and study of relative mechanism, they

243

provided significant information of the carbonization of MOFs.38 Considering the

244

large carbon content, the high thermal stability, and the presence of non-coordination

245

furan rings (an analogue to the additional source in preparing porous carbons), a new

246

type of porous carbon materials (C1000) has been successfully prepared by direct

247

carbonation of 1 in argon atmosphere. To the best of our knowledge, this is the first

248

example of directly carbonizing 2-fold interpenetrated MOFs to prepare porous

249

carbon materials. The SEM images indicated that the obtained C1000 retained the

250

bulk morphology of 1 (Figure 5a and 5b). EDX analysis (Figure 5c) indicated that all

251

the Zn metal in 1 has been removed after carbonization at 1000oC. As shown in

252

Figure 5d, the PXRD

pattern of C1000 only displays two broad peaks at 2θ = 25° 11 ACS Paragon Plus Environment


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Page 12 of 19

253

and 44°, corresponding to carbon (002) and (101) diffraction peaks, respectively.39

254

The broad nature of diffraction peaks indicates the amorphous feature of C1000. In

255

order to get a better knowledge of C1000, TEM and Raman spectra characterizations

256

were conducted. As clearly observed in Figure 6a and b, C1000 has a porous structure,

257

which is consistent with the result of N2 gas adsorption-desorption isotherm. High

258

resolution TEM (HR-TEM) image (Figure 6c) reveals that C1000 possessed lots of

259

nanopores over the entire particle surface with a graphitic structure. This was

260

confirmed by Raman spectra shown in Figure 6d. The intensity ratio (IG/ID) of the

261

peaks roughly at 1367cm-1 (D band) and 1603cm-1 (G band) is 1.02, which indicates

262

that disordered and graphitic structures were developed in the C1000.40

263 264

Figure 5.(a), (b) SEM images; (c) EDS and (d) PXRD pattern of C1000.

265

Gas Adsorption Studies of desolvated 1a and microporous carbon C1000. The

266

as-synthesized crystals were heated at 120 oC for 24 h under high vacuum to obtain

267

the desolvated sample 1a, and the rigid framework of 1a has been verified by PXRD 12 ACS Paragon Plus Environment

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268

pattern (Figure S6). The porosity of desolvated 1a and microporous carbon C1000 has

269

been examined by nitrogen and CO2 absorption experiments. As showed in Figure7a,

270

the N2 adsorption of 1a at 77 K shows a reversible type-I adsorption behavior

271

characteristic

272

Brunauer-Emmett-Teller (BET) and Langmuir surface area of 1a are calculated to be

273

523.6 and 774.7 m2g-1, respectively. Analysis with density functional theory (DFT)

274

from the N2 sorption curve indicates that the size of micropores mainly concentrated

275

around 0.8 nm, which is in accordance with the crystallographic data when van der

276

Waals contact is considered.

of

microporous

material.

Based

on

the

N2

isotherm,

the

277 278

Figure 6. (a), (b) TEM and (c) HR-TEM images of the as-synthesized C1000; (d) Raman spectra of

279

C1000.



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Figure 7. (a) N2 sorption isotherms at 77 K for 1a. Inset: Pore size distribution calculated by DFT. (b)

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CO2 sorption isotherms for 1a at 273 and 298 K.

283

The CO2 sorption isotherms of 1a, measured at 273 and 298 K under ambient

284

pressure, also display type-I adsorption behavior without any hysteresis (Figure 7b).

285

At 1 bar, 1a shows a relatively high CO2 uptakes of 81.8 cm3g-1 (16.1 wt%) at 273 K

286

and 59.2 cm3g-1 (11.6 wt%) at 298K. These values can be well compared to those

287

reported for many MOFs structures under similar conditions.41 It is well documented

288

that open metal sites in MOFs are very beneficial for enhancing the adsorption

289

capacities of gases. It should be noted that 1a does not have any open metal sites. The

290

non-coordination furan rings, which are located on the wall of pores of 1a and can be

291

as functional group with electron rich property, may play a certain degree of

292

contribution to its relatively high CO2 uptake .42

293


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294

Figure 8. (a) N2 sorption isotherms at 77 K for C1000. Inset : Pore size distribution calculated by DFT.

295

(b) CO2 sorption isotherms for C1000 at 273 K.

296

The typical type-I isotherm of N2 sorption at 77 K for C1000 also exhibits a

297

steep increase in the very low P/P0 range, suggesting microporsity of the obtained

298

carbon material (Figure 8a). The BET and Langmuir surface areas of C1000 are

299

calculated to be 362.4 and 505.1 m2 g-1, respectively, slightly lower than those of

300

desolvated 1a. Microporous carbon C1000 still exhibits a certain degree of CO2

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adsorption capacity, with uptake of 64.8 cm3g-1 (12.7 wt%) at 273 K and 1 bar.

302

However, a slight hysteresis is observed in contrast to the completely reversible

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adsorption for 1a, Figure 8b. The hysteresis sorption behavior of C1000 may be

304

attributed to the residual N atoms in carbon material, which derive from N-doped

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ligand L2- and have a relatively strong interaction with absorbed CO2. Recently, Bai et

306

al used Co-MOF as precursors to prepare multiwalled carbon nanotubes with a high

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BET surface area (400-500m2 g-1) by direct pyrolysis of MOFs particles, in which the

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Co-MOF can provide both carbon sources and metal catalysts for the formation of

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carbon nanotubes during the carbonization. 43 Compared with the metal doped carbon

310

nanotubes, the metal-free C1000 has a lower BET surface area，while, its CO2

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adsorption capacity (2.9 mol kg-1) doubled that of the CN-1 (1.4 mol kg-1) at 1 bar.

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CONCLUSION

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In summary, we have successfully synthesized a new 3D two-fold interpenetrated

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metal-organic framework 1. Due to the chelating effect of trepyridyl moieties in L2-

315

ligands and the absence of solvent coordination sites on Zn(II), complex 1 exhibits a

316

good thermal and acid-proof stability, and can be directly carbonized into a new

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microporous carbon material C1000. Both desolvated 1a and the obtained

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microporous carbon C1000 show a relatively good CO2 sorption capacity. Further

319

studies on supercapacitor electrodes based on such carbon material are underway.



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Page 16 of 19

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ASSOCIATED CONTENT

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Additional structures figures , IR spectra, TGA curve, PXRD patterns,

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crystallographic data and structure refinement details for complex 1, selected bond

323

lengths and bond angles, TOPOS results, X-ray crystallographic files in CIF format

324

for complex 1 (CCDC: 1431933). This material is available free of charge via the

325

Internet at http://pubs.acs.org.

326

AUTHOR INFORMATION

327

Corresponding Author

328

*E-mail: [email protected] (C.-Z. L).

329

Notes

330

The authors declare no competing financial interest.

331 332

ACKNOWLEDGMENT

333

This work was supported by the 973 key program of the Chinese Ministry of Science

334

and Technology (MOST) (2012CB821705), the Chinese Academy of Sciences

335

(KJCX2-YW-319, KJCX2-EW-H01), the National Natural Science Foundation of

336

China (21373221, 21221001, 91122027, 51172232, 21403236 ) and the Natural

337

Science Foundation of Fujian Province (2012J06006, 2014J05026, 2006L2005).

338

REFERENCES

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For Table of Contents Use Only

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Synthesis, Photoluminescence and Gas Adsorption Properties of a New Furan-Functionalized MOF and Direct Carbonization for Synthesis of Porous Carbon

428

Jun Zhang

429

†Key Laboratory of Design and Assembly of Functional Nanostructures, Fujian

430

Institute of Research on the Structure of Matter, Chinese Academy of Sciences

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Fuzhou, Fujian 350002, P.R. China

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‡Fujian Provincial Key Laboratory of Nanomaterials, Fujian Institute of Research on

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the Structure of Matter, Chinese Academy of Sciences

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§University of Chinese Academy of Sciences Beijing, 100049, P.R. China

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Corresponding Author: E-mail: [email protected]

†,‡,§

, Wenbin Yang†,‡, Xiao-Yuan Wu†,‡, Lei Zhang†,‡, and Can-Zhong Lu*,†, ‡

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437 438 439 440 441 442 443 444

We report the synthesis of a new ultra stable MOF with furan-functionalized pores, ZnL•5H2O (1), which can stabilize up to 450℃ and remain stable in HCl solution (pH=1) up o to a month. Direct carbonization of 1 under argon atmosphere at 1000 C generates porous carbon C1000, both complex 1 and C1000 have a rather good CO2 adsorption capacity. At 273 K, the uptake of complex 1 and C1000 under 1 bar reaches 81.8

cm3g-1 (16.1 wt%) and 64.8 cm3g-1 (12.7 wt%), respectively. In addition, complex 1 exhibits an interesting photoluminescence. 19 ACS Paragon Plus Environment

Synthesis, Photoluminescence, and Gas ... - ACS Publications

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