Topology-guided design and syntheses of highly stable mesoporous porphyrinic zirconium metal-organic frameworks with high surface area

Article abstract of DOI:10.1021/ja5111317

Through a topology-guided strategy, a series of Zr₆-containing isoreticular porphyrinic metal-organic frameworks (MOFs), PCN-228, PCN-229, and PCN-230, with ftw-a topology were synthesized using the extended porphyrinic linkers. The bulky porphyrin ring ligand effectively prevents the network interpenetration which often appears in MOFs with increased linker length. The pore apertures of the structures range from 2.5 to 3.8 nm, and PCN-229 demonstrates the highest porosity and BET surface area among the previously reported Zr-MOFs. Additionally, by changing the relative direction of the terminal phenyl rings, this series replaces a Zr₈ cluster with a smaller Zr₆ cluster in a topologically identical framework. The high connectivity of the Zr₆ cluster yields frameworks with enhanced stability despite high porosity and ultralarge linker. As a representative example, PCN-230, constructed with the most extended porphyrinic linker, shows excellent stability in aqueous solutions with pH values ranging from 0 to 12 and demonstrates one of the highest pH tolerances among all porphyrinic MOFs. This work not only presents a successful example of rational design of MOFs with desired topology, but also provides a strategy for construction of stable mesoporous MOFs.

Full text of DOI:10.1021/ja5111317

Article
pubs.acs.org/JACS
Topology-Guided Design and Syntheses of Highly Stable
Mesoporous Porphyrinic Zirconium Metal−Organic Frameworks with
High Surface Area
Tian-Fu Liu,†,§ Dawei Feng,†,§ Ying-Pin Chen,†,‡ Lanfang Zou,† Mathieu Bosch,† Shuai Yuan,†
Zhangwen Wei,† Stephen Fordham,† Kecheng Wang,† and Hong-Cai Zhou*,†
†Department of Chemistry, Texas A&M University, College Station, Texas 77842-3012, United States
‡Department of Material Science and Engineering, Texas A&M University, College Station, Texas 77843, United States
S
* Supporting Information
ABSTRACT: Through a topology-guided strategy, a series of
Zr6-containing isoreticular porphyrinic metal−organic frame-
works (MOFs), PCN-228, PCN-229, and PCN-230, with ftw-a
topology were synthesized using the extended porphyrinic
linkers. The bulky porphyrin ring ligand effectively prevents the
network interpenetration which often appears in MOFs with
increased linker length. The pore apertures of the structures
range from 2.5 to 3.8 nm, and PCN-229 demonstrates the
highest porosity and BET surface area among the previously
reported Zr-MOFs. Additionally, by changing the relative
direction of the terminal phenyl rings, this series replaces a
Zr8 cluster with a smaller Zr6 cluster in a topologically identical
framework. The high connectivity of the Zr6 cluster yields frameworks with enhanced stability despite high porosity and
ultralarge linker. As a representative example, PCN-230, constructed with the most extended porphyrinic linker, shows excellent
stability in aqueous solutions with pH values ranging from 0 to 12 and demonstrates one of the highest pH tolerances among all
porphyrinic MOFs. This work not only presents a successful example of rational design of MOFs with desired topology, but also
provides a strategy for construction of stable mesoporous MOFs.
cavity of known MOF structures, the pore size and stability are
usually inversely correlated.
INTRODUCTION
■
Mesoporous metal−organic frameworks (MOFs) have at-
tracted great interest as heterogeneous platforms to immobilize
or encapsulate functional moieties, such as organometallic
catalysts, nanoparticles, and enzymes.1,2 However, compared
with the well-explored microporous MOFs, mesoporous MOFs
are relatively under-developed. This is ascribed to the difficulty
in organic linker extension, challenges in activation of MOFs
with ultralarge pores, as well as the common appearance of
undesired interpenetration.2b,3 Moreover, the stability of the
framework becomes difficult to maintain after extension of the
organic linker, especially for mesoporous materials whose
applications are usually conducted under aqueous or harsh
chemical environments. The majority of reported carboxylate
containing MOFs are constructed with relatively soft Lewis
acidic metal species, such as Cu2+ and Zn2+. The weak
coordination bond between the soft Lewis acid and hard Lewis
base causes their low stability and severely hampers further
exploration of their potential.4 To improve the chemical
stability of MOFs, hard Lewis acidic species such as Al3+, Fe3+,
Cr3+, and Zr4+, which can form much stronger bonds with
carboxylates, are often incorporated.5,6 Despite this adjustment,
as isoreticular chemistry is applied to augment the internal
One strategy to compensate for the low stability of MOFs
constructed with large linkers is to increase the connectivity of
both organic linkers and inorganic clusters.7 The Zr6 cluster
(Zr6O4OH4(COO)12), which has the highest connectivity
among reported zero-dimensional (0-D) inorganic nodes in
MOFs, is an outstanding example which endows the framework
with excellent stability.6 In particular, when the linker also
exhibits high connectivity, the obtained MOFs are manifested
to be robust even with very large pore size.8 Hence, further
increasing the overall connectivity of Zr-MOFs could be an
effective strategy allowing construction of highly stable
mesoporous MOFs with ultralarge linkers.
Porphyrinic derivatives as organic linkers have been
extensively explored in MOFs due to their versatile
functionality, such as catalysis, light harvesting, and sensing.9
Moreover, porphyrinic linkers usually have very large size (∼2
nm), which assists in generating large pores inside the
frameworks, resulting in mesoporous MOFs. In order to
achieve the high connectivity, we used tetratopic carboxylate
Received: November 2, 2014
© XXXX American Chemical Society
A
DOI: 10.1021/ja5111317
J. Am. Chem. Soc. XXXX, XXX, XXX−XXX

Journal of the American Chemical Society
Article
Synthesis of H4TCP-1, H4TCP-2, and H4TCP-3. Shown in
Scheme 1. Details in SI, Section S2.
porphyrin ligand H4TCPP (tetrakis(4-carboxyphenyl)-
porphyrin) and the 12-connected Zr6 cluster to construct
mesoporous MOFs. The fully occupied Zr6 is 12-connected
with Oh symmetry, and the free H4TCPP is four-connected
with D4h symmetry (Figure 1). Topological connection of these
Scheme 1. Syntheses of H4TCP-1, -2, and -3 Using the
a
Precursors n1, n2, and n3
Figure 1. Assembly of Oh and D4h nodes into ftw-a network.
two nodes to each other could ideally give rise to a highly
connected ftw-a network. However, not only the connectivity
and symmetry of nodes, but also the direction and relative
position of each node, are crucial for topological design, and the
latter is often neglected when modulating the building units to
obtain the desired structure. In other words, even if both
connectivity and symmetry are perfectly matched, it is still not
possible to form the expected framework if the relative
directions of nodes are not correctly arranged.10
Herein, guided by topology and symmetry, porphyrinic
linkers (named as H4TCP-1, H4TCP-2, and H4TCP-3) were
elongated with desired conformation by arranging the vicinal
phenyl ring and carboxylate group. Through combination of the
organic linkers and 12-connected Zr6 cluster, a series of
mesoporous MOFs with ftw-a topology, namely PCN-228,
PCN-229, and PCN-230 (PCN stands for porous coordination
network), were synthesized. The pore size of these MOFs
ranges from 2.5 to 3.8 nm, and PCN-229 shows both the
highest porosity as well as BET surface area among all the
previously reported Zr-MOFs. Moreover, the ligand extension
does not impair the stability of the material. PCN-230, as a
representative, which is constructed with the most extended
linker, shows excellent stability in aqueous solutions with pH
ranging from 0 to 12, demonstrating the highest pH tolerance
among all previously reported porphyrinic MOFs.
a
Details of the synthetic procedure are given in the SI.
EXPERIMENTAL SECTION
General Information. The commercial chemicals are used as
purchased unless otherwise mentioned. Detailed chemical sources are
provided in the Supporting Information (SI).
Synthesis of PCN-228. (Zr6(OH)4O4(TCP-1)3·10DMF·2H2O).
ZrCl4 (15 mg), H4TCP-1 (15 mg), and benzoic acid (350 mg) in 2
mL of DMF were ultrasonically dissolved in a 4 mL Pyrex vial. The
mixture was heated to 120 °C in an oven for 12 h. After cooling down
to room temperature, dark green crystals 16 mg were harvested by
filtration (Yield. 85%). Found. C, 67.51; H, 5.63; N, 4.56%.
Synthesis of PCN-229. (Zr6(OH)4O4(TCP-2)3·45DMF·25H2O).
ZrCl4 (15 mg), H4TCP-2 1415 (15 mg), and benzoic acid (350 mg) in
2 mL of DMF were ultrasonically dissolved in a 4 mL Pyrex vial. The
mixture was heated to 120 °C in an oven for 12 h. After cooling down
to room temperature, dark green crystals 14 mg were harvested by
filtration (Yield. 82%). Found. C, 56.98; H, 5.95; N, 7.20%.
Synthesis of PCN-230. (Zr6(OH)4O4(TCP-3)3·30DMF·10H2O).
ZrCl4 (15 mg), H4TCP-3 (20 mg), and acetic acid (0.4 mL) in 2 mL
of DMF were ultrasonically dissolved in a 4 mL Pyrex vial. The
mixture was heated to 120 °C in an oven for 24 h. After cooling down
to room temperature, dark green crystals 20 mg were harvested by
filtration (Yield. 91%). Found. C, 53.83; H, 4.49; N, 2.60%.
Single-Crystal X-ray Crystallography. Single-crystal X-ray
crystallographic data of PCN-228′ and PCN-230 were collected on
a Bruker single-crystal APEXII CCD diffractometer with Mo Kα (λ =
■
Instrumentation. The powder X-ray diffraction patterns (PXRD)
were recorded on a Bruker D8-Focus Bragg−Brentano X-ray Powder
diffractometer equipped with a Cu sealed tube (λ = 1.54178 Å) at
room temperature. Synchrotron PXRD measurements were carried
out on the beamline 17-BM at the Advanced Photon Source, Argonne
National Laboratory, using a wavelength of 0.72775(5) Å and a
Perkin-Elmer amorphous-Si Flat Panel Detector. The simulated PXRD
spectra were obtained by the diffraction-crystal module of the Mercury
program based on the single-crystal data. The program is available free
of charge via the Internet at http:/www.iucr.org. Thermogravimetric
analysis (TGA) was conducted on a TGA-50 (Shimadzu)
thermogravimetric analyzer in the air atmosphere. Nuclear magnetic
resonance (NMR) data were collected on a Mercury 300
spectrometer. Gas sorption measurements were conducted using a
Micrometritics ASAP 2020 system at different temperatures. PCN-229
or PCN-230 were activated by supercritical carbon dioxide using
MADRIDE prior to gas adsorption.
B
DOI: 10.1021/ja5111317
J. Am. Chem. Soc. XXXX, XXX, XXX−XXX

Journal of the American Chemical Society
Article
0.71073 Å) at 110 K. All structures were solved by direct methods and
refined by full-matrix least-squares on F2 using SHELXTL.11 Non-
hydrogen atoms were refined with anisotropic displacement
parameters during the final cycles. Organic hydrogen atoms were
placed in calculated positions with isotropic displacement parameters
set to 1.2Ueq of the attached atom. The solvent molecules are highly
disordered, and attempts to locate and refine the solvent peaks were
unsuccessful. Contributions to scattering due to these solvent
molecules were removed using the SQUEEZE routine of PLATON;12
structures were then refined again using the data generated. Crystal
data were summarized in Table 1. The CIF file can be obtained free of
portions and transferred to vials containing aqueous solutions with
different pH values. After 24 h, the samples were washed with fresh
DMF twice for PXRD measurement (SI, Figures S5−S7) or activated
by supercritical CO2 for N2 adsorption.
RESULTS AND DISCUSSION
■
Porphyrinic ligands were chosen for reticular chemistry in this
work for several reasons. The porphyrin ligand is synthesized
from a condensation reaction; elongation of the precursor
provides a facile method for the effective enlargement of the
target ligands. The elongated porphyrin is relatively easier to
synthesize compared with other organic linkers with com-
parable size. Additionally, the center of a porphyrin is a highly
conjugated bulky solid ring, which usually inherently prevents
interpenetration. Therefore, using a porphyrinic organic linker
could be an effective approach to obtain extra-large pores in
MOFs. Moreover, the porphyrin center endows the obtained
mesoporous MOFs with versatile functionality which has
potential for a wide array of applications. Owing to their
large size and the use of relatively soft Lewis acidic metal
species as nodes, most reported porphyrinic MOFs suffer from
weak stability, which severely hampers their application.
Utilizing hard Lewis acidic species as inorganic nodes in
porphyrinic MOFs has remarkably improved the chemical
stability and extended their use under harsh chemical
environments.8,13
Table 1. Crystal Data for PCN-228′ and PCN-230
PCN-228′
PCN-230
formula
FW
C216H120N12O32Ni3Zr6
4118.69
C408H318N12O32Zr6
6448.06
shape
red square plate
cubic
red square plate
cubic
crystal system
space group
a (Å)
Pm3m
Pm3m
̅
̅
25.3468(6)
90
38.4224(12)
α (deg)
V (Å3)
90
16284.3(7)
1
56722(3)
1
Z
T (K)
110(2)
0.420
110(2)
0.189
dcalcd (g/cm3)
μ(mm−1
)
0.199
0.037
F(000)
2080
3346
As shown in Figure 1, the ftw-a network is composed of the
12-connected Oh nodes and 4-connected D4h nodes. However,
when substituting the corresponding nodes with the 12-
connected Zr6 clusters and TCPP ligands to construct ftw-a
topology, the peripheral phenyl rings have to rotate into the
same plane with the porphyrin. The rotation on position I
(Figure 2a) is forbidden because of the steric effect between the
porphyrin ring and the phenyl ring. The rotation on position II
would destroy the conjugated system between carboxylates and
benzene rings, which is also highly energetically nonpreferred.
Therefore, these two building units are difficult to form the ftw-
a network because of their incompatible direction (Figure 2b).
The previously reported Zr6 cluster usually adopts reduced
connectivity and symmetry to form other networks with
TCPP,8,13d or it is fully occupied by TCPP with an energetically
disfavored conformation.13c Alternatively, the Zr8 cluster needs
to be incorporated with TCPP to construct ftw-a network as
represented in PCN-221 (Figure 2d). However, this framework
is not stable in aqueous environments because of the charge
unbalanced Zr8 cluster.13e
To overcome such conflicts and construct stable mesoporous
porphyrinic Zr-MOFs with ftw-a topology, the elongated
porphyrinic ligands H4TCP-1, H4TCP-2, and H4TCP-3 were
designed with desired conformation by carefully arranging the
vicinal phenyl rings and carboxylate groups. By taking
advantage of the steric effect between porphyrin center and
connected phenyl rings as well as the adjacent two phenyl rings,
the four carboxylate groups in H4TCP-1 are likely to stay in the
same plane with the porphyrin center which is necessary to
form the ftw-a network with Zr6. In contrast, we try to alleviate
the steric effect as much as possible for H4TCP-2 and H4TCP-
3. The ethynyl group is known to promote low or no barrier
torsional motion for the vicinal phenyl rings.14 In H4TCP-2
and H4TCP-3, ethynyl moieties were used for ligand
elongation, which allow the peripheral benzoates to rotate
freely to stay in the same plane as the porphyrin center without
significantly increasing the inherent energy. Therefore, the
θmax (deg)
25.99
23.99
completeness (%)
collected reflections
unique reflections
parameters
99.9
99.8
171 630
3148
500 577
8348
50
66
restraints
29
61
Rint
0.0882
0.0968
0.2618
0.1023
0.2683
1.005
0.5735
0.1602
0.3489
0.1625
0.3505
1.004
R1 [I > 2σ(I)]
wR2 [I > 2σ(I)]
R1 (all data)
wR2 (all data)
GOF on F2
Δρmax/Δρmin (e·Å−3
)
2.599/−1.294
1.016/−1.193
charge from the Cambridge Crystallographic Data Centre via www.
ccdc.cam.ac.uk/data_request/cif (CCDC 1038049 for PCN-228′,
1038050 for PCN-230). After the initial structural solution was
found on the basis of the single-crystal X-ray diffraction data of PCN-
228′, the structures of PCN-228 and -229 were refined by a self-
consistent iterative procedure in which successive geometry
optimization calculations were performed using the Forcite module
of Materials Studio 6.0.15 Detailed information about PCN-228 and
PCN-228′ is present in the SI.
Gas Adsorption of PCN-228, PCN-229, and PCN-230. Before
the gas sorption experiment, as-synthesized PCN-228(∼100 mg) was
washed twice with DMF and acetone, respectively. Fresh acetone was
subsequently added, and the sample was allowed to soak for 24 h to
exchange and remove the nonvolatile solvates (DMF). After the
removal of acetone by decanting, the samples were activated by drying
under vacuum, then dried again by using the “outgas” function of the
adsorption instrument for 5 h at 100 °C prior to gas adsorption/
desorption measurement. For PCN-229 and PCN-230, the as-
synthesized samples (∼100 mg) were washed with DMF three times
and then soaked in fresh DMF overnight. Afterward, the samples were
activated by supercritical CO2 and then dried again by using the
“outgas” function of the adsorption instrument for 5 h at 100 °C prior
to gas adsorption/desorption measurement.
Stability Test of PCN-228, -229, and -230. Portions of about
200 mg of as-synthesized samples were separated into several smaller
C
DOI: 10.1021/ja5111317
J. Am. Chem. Soc. XXXX, XXX, XXX−XXX

Journal of the American Chemical Society
Article
Figure 2. (a) Representation of the connections between the Oh node
and D4h node when combining Zr6 and H4TCPP, and the sterically
controlled phenyl and carboxylate angle. (b) Substitution of the Zr6
cluster and H4TCPP in ftw-a topology and the chemically forbidden
conformation of ligand (highlighted with red circle). (c) Representa-
tion of the Zr6 and Zr8 cluster, and the 90° rotation of the carboxylate
groups between these two clusters. (d) Structure of PCN-221
constructed with Zr8 cluster and H4TCPP. (e) Structure of PCN-228
constructed with Zr6 cluster and H4TCP-1 (ethyl groups were omitted
for clarity).
ligands can adopt a compatible direction with the Zr6 cluster to
construct fta-w network. Meanwhile, eight ethyl substituents
were introduced in the porphyrin rings aiming to increase the
solubility of ligands (Scheme 1). Solvothermal reaction of
H4TCP-1, H4TCP-2 , or H4TCP-3 with ZrCl4 and acetic acid
in DMF gives rise to large, dark green cubic crystals, namely
PCN-228, PCN-229, and PCN-230, respectively (Figure 3a−
c). Single-crystal X-ray diffraction reveals a space group of
Figure 3. Structures and crystals of (a) PCN-228, (b) PCN-229, and
(c) PCN-230. (d) Experimental and simulated PXRD of PCN-228,
-229, and -230. (Simulated PXRD of PCN-228 and PCN-229 were
calculated from the simulated structure.)
Pm3m for PCN-228′ and -230 (see SI for details of PCN-228
̅
and PCN-228′). The overall frameworks are based on uniform
cubes, each of which has faces consisting of the porphyrinic
linker. Although single crystals are also obtained for PCN-229,
the diffraction is too weak to solve the structure due to their
relatively small size. Hence, an isoreticular structure model of
PCN-229 was constructed using Material Studio 6.0,15 and
further confirmed by synchrotron PXRD collected at 17-BM
beamline at Advanced Photon Source, Argonne National
Laboratory. PCN-228 and PCN-230 are also confirmed by
the PXRD patterns (Figure 3d). Due to the extra-large size of
these porphyrinic linkers, all three MOFs are mesoporous with
pore size ranging from 2.5 to 3.8 nm (Figure 3a−c). As we
expected, all the peripheral benzoates stay in plane with the
porphyrin center, which allows the formation of the ftw-a
network with the 12-connected Zr6 cluster. Although these
MOFs are constructed from Zr6 clusters, they share the same
space group and topology with PCN-221, wherein the
peripheral benzoates in TCPP are perpendicular to the central
porphyrin ring. Structural analysis of PCN-221 has shown the
carboxylate groups of the Zr8 cluster have a 90° rotation
compared with that of the Zr6 cluster (Figure 2c). With this
orientation, these two nodes are compatible to form the ftw-a
topology. However, even with theoretically qualified nodes,
some reported zirconium porphyrin MOFs possess reduced
connectivity and symmetry due to the incompatible direction-
D
DOI: 10.1021/ja5111317
J. Am. Chem. Soc. XXXX, XXX, XXX−XXX

Journal of the American Chemical Society
Article
ality of the metal nodes and linker, resulting in the obtained
frameworks with diminished pH stability compared with the
12-connected PCN-228 series.5e,8,13c,d These examples dem-
onstrate that not only the symmetry, but also the relative
direction of each node, must be considered in topological
MOFs design.
To the best of our knowledge, PCN-230 exhibits the largest
pore among all Zr-MOFs. If we consider Zr-MOF growth as a
ligand substitution process taking place with Zr clusters, it is a
more entropically favored process when the connecting number
on the cluster is higher.16 Supposing that bond energy of the
Zr-carboxylate bond is similar for different connectivity
arrangements, the 12-connected porphyrinic Zr-MOFs could
be energetically more favored compared to other porphyrinic
Zr-MOFs with lower connectivity (it should have a lower Gibbs
free energy due to the entropy effect).
calculated to be 4178 m2/g for PCN-228, 4935 m2/g for PCN-
229 and 7154 m2/g for PCN-230 by Materials Studio 6.0 using
the “atom volumes and surfaces” function. The inconsistency of
experimental and calculated surface area comes from the
difficulty in activation of ultrahigh porosity material. The
extremely large cavity can easily trap unreacted ligands and
metal clusters which are difficult to remove during the
activation process. From TGA curves, we can see that the
weight loss of PCN-230 is smaller than that of PCN-229 after
solvent removal at 100 °C (SI, Figure S8). Moreover, PCN-230
left more residue than PCN-229 after complete decomposition.
This unusual phenomenon supports the idea that PCN-230
may contain bulky trapped species that could not be removed.
Moreover, PCN-230 has the lowest stability among these
MOFs, which also accounts for the unexpectedly low N2 uptake
compared with PCN-228 and PCN-229.
Since high volumetric surface area is also crucial for some
applications, several highly porous MOFs were selected for
comparison of the volumetric and gravimetric surface area and
listed in Table 2. The MOFs reported in this work show high
gravimetric surface areas. Especially when the volumetric
surface area is considered, PCN-228 is very outstanding
among those well-known MOFs. Typically, the MOFs with
large pore size possess relative low gravimetric and volumetric
surface area. However, PCN-228 and PCN-229 possess much
higher gravimetric and volumetric surface area compared with
PCN-221 bearing much smaller pore size. The great improve-
ment of both the volumetric and gravimetric surface areas can
be ascribed to the replacement of the Zr8 clusters with the
smaller Zr6 clusters. The low volumetric surface area of PCN-
230 can be ascribed to its extremely low crystal density (0.189
g/cm3). However, it is still comparable with PCN-221 which
has higher density (0.48 g/cm3) but much lower gravimetric
surface area. Overall, this series of mesoporous MOFs possesses
high and permanent porosity after removal of solvent
molecules, demonstrating its excellent physical stability.
In order to assess the porosity of PCN-228, -229, and -230,
we performed N2 sorption measurement at 77 K. PCN-228,
PCN-229, and PCN-230 show N2 uptakes of 1245, 1455, and
1085 cm3/g, respectively (Figure 4a). The experimental
Brunauer−Emmett−Teller (BET) surface area is 4510 m2/g
for PCN-228, 4619 m2/g for PCN-229, and 4455 m2/g for
PCN-230. PCN-229 shows both the highest porosity and BET
surface area among all the previously reported Zr-MOFs as well
as among porphyrinic MOFs. The BET surface areas were
The Zr6 cluster is fully occupied by 12 carboxylates from the
porphyrinic linkers and gives rise to the highest connectivity
among Zr-MOFs, hence this series of MOFs were expected to
possess excellent chemical stability. We tested the chemical
stability of PCN-230 as a representative, with consideration
that MOF stability decreases along with the increase of the
linker length for isoreticular structures. After being soaked in
aqueous solutions with pH values ranging from 0 to 12
(prepared with HCl and NaOH solution respectively) for 24 h,
the PXRD patterns of PCN-230 are almost unaltered, which
suggests maintenance of the crystallinity (SI, Section S4). To
further confirm that the frameworks were intact, we performed
N2 adsorption measurement for samples after different
treatments. N2 uptake measurements of PCN-230 after
treatment have minimal deviation from the pristine sample,
which indicates the robustness of the framework under harsh
chemical conditions (Figure 4b). To our knowledge, PCN-230
shows the highest stability in the widest pH range among
previously reported porphyrinic MOFs despite its extremely
large linker. Stability tests of PCN-228 and PCN-229 treated
with different aqueous solutions were also conducted (SI,
Figures S5 and S6). The well maintained PXRD patterns of the
samples after different treatments demonstrate that PCN-228
and PCN-229 are stable even in 1 M HCl for 24 h, displaying
higher stability than PCN-230. This series of Zr-MOFs with
elongated linkers successfully realize the combination of meso-
Figure 4. (a) N2 adsorption isotherms of PCN-228, PCN-229, and
PCN-230. (b) N2 adsorption isotherms of PCN-230 after different
treatment.
E
DOI: 10.1021/ja5111317
J. Am. Chem. Soc. XXXX, XXX, XXX−XXX

Journal of the American Chemical Society
Article
Table 2. Volumetric and Gravimetric BET Surface Areas (SA) of Some Highly Porous MOFs
NU-
110E
MOF-
210
PCN- UMCM
NU-
111
PCN-
229
PCN-
228
PCN-
230
MIL-
101-Cr
MOF
-5
PCN-
14
MOF-
74Mg
PCN- HKUST
a
610
-2
221
-1
gravimetric SA
(m2/g)
7140
6240
6143
5200
4930
4619
4510
4455
3870
3800
1984
1957
1936
1663
density (g/cm3)
0.237
1692
0.25
0.303
1861
0.4
0.409
2016
0.32
0.42
0.189
842
0.44
0.59
0.829
1644
0.909
1779
0.48
929
0.881
1465
volumetric SA
(m2/cm3)
1560
2080
1478
1894
1702
2242
reference
7b
19, 23
7a, 20
18
19
b
b
b
21
17
19
19
13e
22
a
b
Also named as NU-100. This work.
J. S.; Jhung, S. H.; Seo, Y. K.; Kim, J.; Vimont, A.; Daturi, M.; Serre, C.;
Fer
porosity with high stability, and would be of great potential for
application in nanoscale chemistry.
́
ey, G. Angew. Chem., Int. Ed. 2008, 47, 4144−4148. (d) Chen, Y.;
Lykourinou, V.; Vetromile, C.; Hoang, T.; Ming, L.-J.; Larsen, R. W.;
Ma, S. J. Am. Chem. Soc. 2012, 134, 13188−13191.
In conclusion, through topological and symmetry analysis, we
developed a series of 12-connected Zr6 containing porphyrinic
MOFs with ftw-a topology using elongated porphyrinic linkers.
Among them, PCN-230 exhibits the largest cage (3.8 nm) and
PCN-229 shows both the highest porosity and BET surface
area among previously reported Zr-MOFs. PCN-230, con-
structed with the most extended linker, shows excellent stability
in aqueous solutions with pH ranging from 0 to 12, the widest
range shown by a porphyrinic MOF.
(3) Schaate, A.; Roy, P.; Preuße, T.; Lohmeier, S. J.; Godt, A.;
Behrens, P. Chem.Eur. J. 2011, 17, 9320−9325.
(4) Pearson, R. G. J. Am. Chem. Soc. 1963, 85, 3533−3539.
́
(5) (a) Horcajada, P.; Surble, S.; Serre, C.; Hong, D.-Y.; Seo, Y.-K.;
́
Chang, J.-S.; Greneche, J.-M.; Margiolaki, I.; Ferey, G. Chem. Commun.
2007, 2820−2822. (b) Guillerm, V.; Ragon, F.; Dan-Hardi, M.; Devic,
T.; Vishnuvarthan, M.; Campo, B.; Vimont, A.; Clet, G.; Yang, Q.;
́
Maurin, G.; Ferey, G.; Vittadini, A.; Gross, S.; Serre, C. Angew. Chem.,
Int. Ed. 2012, 51, 9267−9271. (c) Volkringer, C.; Popov, D.; Loiseau,
T.; Ferey, G.; Burghammer, M.; Riekel, C.; Haouas, M.; Taulelle, F.
Chem. Mater. 2009, 21, 5695−5697. (d) Lieb, A.; Leclerc, H.; Devic,
T.; Serre, C.; Margiolaki, I.; Mahjoubi, F.; Lee, J. S.; Vimont, A.;
Daturi, M.; Chang, J.-S. Microporous Mesoporous Mater. 2012, 157, 18−
23. (e) Jiang, H.-L.; Feng, D.; Li, J.-R.; Liu, T.-F.; Zhou, H.-C. J. Am.
Chem. Soc. 2012, 134, 14690−14693. (f) Liu, T. - F.; Zou, L.; Feng, D.;
Chen, Y.-P.; Fordham, S.; Wang, X.; Liu, Y.; Zhou, H.-C. J. Am. Chem.
Soc. 2014, 136, 7813−7816. (g) Wei, Z.; Gu, Z.-Y.; Arvapally, R. K.;
Chen, Y. − P.; McDougald, R. N., Jr.; Ivy, J. F.; Yakovenko, A. A.;
Feng, D.; Omary, M. A.; Zhou, H.- C. J. Am. Chem. Soc. 2014, 136,
8269−8276. (h) Zhang, M.; Chen, Y.-P.; Bosch, M.; Gentle, T.; Wang,
K.; Feng, D.; Wang, Z. U.; Zhou, H.-C. Angew. Chem., Int. Ed. 2014,
53, 815−818.
ASSOCIATED CONTENT
* Supporting Information
Chemicals and instrumentation, full details for sample
preparation, characterization results, additional PXRD patterns,
and TGA. This material is available free of charge via the
Internet at http://pubs.acs.org.
■
S
AUTHOR INFORMATION
Corresponding Author
zhou@mail.chem.tamu.edu
■
Author Contributions
§T.-F.L. and D.F. contributed equally to this work.
(6) (a) Cavka, J. H.; Jakobsen, S.; Olsbye, U.; Guillou, N.; Lamberti,
C.; Bordiga, S.; Lillerud, K. P. J. Am. Chem. Soc. 2008, 130, 13850−
13851. (b) Wang, C.; Wang, J.-L.; Lin, W. J. Am. Chem. Soc. 2012, 134,
19895−19908. (c) Wang, C.; Xie, Z.; deKrafft, K. E.; Lin, W. J. Am.
Chem. Soc. 2011, 133, 13445−13454. (d) Mondloch, J. E.; Bury, W.;
Fairen-Jimenez, D.; Kwon, S.; DeMarco, E. J.; Weston, M. H.; Sarjeant,
A. A.; Nguyen, S. T.; Stair, P. C.; Snurr, R. Q.; Farha, O. K.; Hupp, J.
T. J. Am. Chem. Soc. 2013, 135, 10294−10297. (e) Furukawa, H.;
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
This work was supported as a part of the Center for Gas
Separations Relevant to Clean Energy Technologies, an Energy
Frontier Research Center (EFRC) funded by the U.S.
Department of Energy (DOE), Office of Science, Office of
Basic Energy Sciences under Award Number DE-SC0001015.
It was funded in part by the Advanced Research Projects
Agency − Energy (ARPA-E), U.S. Department of Energy,
under Award Number DE-AR0000249. We gratefully acknowl-
edge the Robert A. Welch Foundation (A-1725) for support of
this work. Use of the Advanced Photon Source, an Office of
Science User Facility operated for the US Department of
Energy (DOE) Office of Science by Argonne National
Laboratory, was supported by the U.S. DOE under Contract
No. DE-AC02-06CH11357.
́
Gandara, F.; Zhang, Y.-B.; Jiang, J.; Queen, W. L.; Hudson, M. R.;
Yaghi, O. M. J. Am. Chem. Soc. 2014, 136, 4369−4381.
(7) (a) Yuan, D.; Zhao, D.; Sun, D.; Zhou, H. − C. Angew. Chem., Int.
Ed. 2010, 49, 5357−5361. (b) Farha, O. K.; Eryazici, I.; Jeong, N. C.;
Hauser, B. G.; Wilmer, C. E.; Sarjeant, A. A.; Snurr, R. Q.; Nguyen, S.
̈
T.; Yazaydın, A. O.; Hupp, J. T. J. Am. Chem. Soc. 2012, 134, 15016−
15021.
(8) Feng, D.; Gu, Z.-Y.; Li, J.-R.; Jiang, H.-L.; Wei, Z.; Zhou, H.-C.
Angew. Chem., Int. Ed. 2012, 51, 10307−10310.
(9) (a) Zou, C.; Wu, C.-D. Dalton Trans. 2012, 41, 3879−3888.
(b) Burnett, B. J.; Barron, P. M.; Choe, W. CrystEngComm 2012, 14,
3839−3846. (c) Alkordi, M. H.; Liu, Y.; Larsen, R. W.; Eubank, J. F.;
Eddaoudi, M. J. Am. Chem. Soc. 2008, 130, 12639−12641. (d) Meng,
L.; Cheng, Q.; Kim, C.; Gao, W.-Y.; Wojtas, L.; Chen, Y.-S.;
Zaworotko, M. J.; Zhang, X. P.; Ma, S. Angew. Chem., Int. Ed. 2012, 51,
10082−10085. (e) Lee, C. Y.; Farha, O. K.; Hong, B. J.; Sarjeant, A. A.;
Nguyen, S. T.; Hupp, J. T. J. Am. Chem. Soc. 2011, 133, 15858−15861.
(f) Son, H.-J.; Jin, S.; Patwardhan, S.; Wezenberg, S. J.; Jeong, N. C.;
So, M.; Wilmer, C. E.; Sarjeant, A. A.; Schatz, G. C.; Snurr, R. Q.;
Farha, O. K.; Wiederrecht, G. P.; Hupp, J. T. J. Am. Chem. Soc. 2013,
135, 862−869. (g) Gao, W.-Y.; Chrzanowski, M.; Ma, S. Chem. Soc.
Rev. 2014, 43, 5841−5866. (h) Park, J.; Feng, D.; Yuan, S.; Zhou, H.-
C. Angew. Chem., Int. Ed. 2014, DOI: 10.1002/anie.201408862.
REFERENCES
■
(1) (a) Zhou, H. C.; Long, J. R.; Yaghi, O. M. Chem. Rev. 2012, 112,
673−674. (b) Zhou, H.-C.; Kitagawa, S. Chem. Soc. Rev. 2014, 43,
5415−5418.
(2) (a) Zhu, Q.-L.; Xu, Q. Chem. Soc. Rev. 2014, 43, 5468−5512.
(b) Deng, H.; Grunder, S.; Cordova, K. E.; Valente, C.; Furukawa, H.;
́
Hmadeh, M.; Gandara, F.; Whalley, A. C.; Liu, Z.; Asahina, S.;
Kazumori, H.; O’Keeffe, M.; Terasaki, O.; Stoddart, J. F.; Yaghi, O. M.
Science 2012, 336, 1018−1023. (c) Hwang, Y. K.; Hong, D. Y.; Chang,
F
DOI: 10.1021/ja5111317
J. Am. Chem. Soc. XXXX, XXX, XXX−XXX

Journal of the American Chemical Society
Article
(10) Li, M.; Li, D.; O’Keeffe, M.; Yaghi, O. M. Chem. Rev. 2014, 114,
1343−1370.
(11) Sheldrick, G. Acta Crystallogr. A 2008, 64, 112−122.
(12) Spek, A. J. Appl. Crystallogr. 2003, 36, 7.
(13) (a) Fateeva, A.; Chater, P. A.; Ireland, C. P.; Tahir, A. A.;
Khimyak, Y. Z.; Wiper, P. V.; Darwent, J. R.; Rosseinsky, M. J. Angew.
Chem., Int. Ed. 2012, 51, 7440−7444. (b) Chen, Y.; Hoang, T.; Ma, S.
Inorg. Chem. 2012, 51, 12600−12602. (c) Morris, W.; Volosskiy, B.;
́
Demir, S.; Gandara, F.; McGrier, P. L.; Furukawa, H.; Cascio, D.;
Stoddart, J. F.; Yaghi, O. M. Inorg. Chem. 2012, 51, 6443−6445.
(d) Feng, D.; Chung, W.-C.; Wei, Z.; Gu, Z.-Y.; Jiang, H.-L.; Chen, Y.-
P.; Darensbourg, D.; Zhou, H.-C. J. Am. Chem. Soc. 2013, 135, 17105−
17110. (e) Feng, D.; Jiang, H.-L.; Chen, Y.−P.; Gu, Z.-Y.; Wei, Z.;
Zhou, H.-C. Inorg. Chem. 2013, 52, 12661−12667. (f) Feng, D.; Gu,
Z.-Y.; Chen, Y.-P.; Park, J.; Wei, Z.; Sun, Y.; Bosch, M.; Yuan, S.; Zhou,
H.-C. J. Am. Chem. Soc. 2014, 136, 17714−17717.
(14) Okuyama, K.; Hasegawa, T.; Ito, M.; Mikami, N. J. Phys. Chem.
1984, 88, 1711−1716.
(15) Accelerys Materials Studio Release Notes, Release 5.5.1; Accelrys
Software, Inc.: San Diego, 2010.
(16) Feng, D.; Wang, K.; Wei, Z.; Chen, Y.-P.; Simon, C. M.;
Arvapally, R. K.; Martin, R. L.; Bosch, M.; Liu, T.-F.; Fordham, S.;
Yuan, D.; Omary, M. A.; Haranczyk, M.; Smit, B.; Zhou, H.-C. Nature
Commun. 2014, 5, No. 5723.
(17) Kaye, S. S.; Dailly, A.; Yaghi, O. M.; Long, J. R. J. Am. Chem. Soc.
2007, 129, 14176−14177.
(18) Koh, K.; Wong-Foy, A. G.; Matzger, A. J. J. Am. Chem. Soc.
2009, 131, 4184−4185.
(19) Mason, J. A.; Veenstrab, M.; Long, J. R. Chem. Sci. 2014, 5, 32−
51.
̈
(20) Farha, O. K.; Yazaydın, A. O.; Eryazici, I.; Malliakas, C. D.;
Hauser, B. G.; Kanatzidis, M. G.; Nguyen, S. T.; Snurr, R. Q.; Hupp, J.
T. Nature Chem. 2010, 2, 944−948.
(21) Wiersum, A. D.; Chang, J.-S.; Serre, C.; Llewellyn, P. L.
Langmuir 2013, 29, 3301−3309.
(22) Chowdhury, P.; Mekala, S.; Dreisbach, F.; Gumma, S.
Microporous Mesoporous Mater. 2012, 152, 246−252.
(23) Furukawa, H.; Ko, N.; Go, Y. B.; Aratani, N.; Choi, S. B.; Choi,
̈
E.; A. Yazaydin, O.; Snurr, R. Q.; O’Keeffe, M.; Kim, J.; Yaghi, O. M.
Science 2010, 329, 424−428.
G
DOI: 10.1021/ja5111317
J. Am. Chem. Soc. XXXX, XXX, XXX−XXX