Remarkable Structural Diversity between Zr/Hf and Rare-Earth MOFs via Ligand Functionalization and the Discovery of Unique (4, 8)-c and (4, 12)-connected Frameworks

Article abstract of DOI:10.1021/jacs.0c07081

Ligand modification in MOFs provides great opportunities not only for the development of functional materials with new or enhanced properties but also for the discovery of novel structures. We report here that a sulfone-functionalized tetrahedral carboxylate-based ligand is capable of directing the formation of new and fascinating MOFs when combined with Zr4+/Hf4+ and rare-earth metal cations (RE) with improved gas-sorption properties. In particular, the resulting M-flu-SO2 (M: Zr, Hf) materials display a new type of the augmented flu-a net, which is different as compared to the flu-a framework formed by the nonfunctionalized tetrahedral ligand. In terms of properties, a remarkable increase in the CO2 uptake is observed that reaches 76.6% and 61.6% at 273 and 298 K and 1 bar, respectively. When combined with REs, the sulfone-modified linker affords novel MOFs, RE-hpt-MOF-1 (RE: Y3+, Ho3+, Er3+), which displays a fascinating (4, 12)-coordinated hpt net, based on nonanuclear [RE9(μ3-?)2(μ3-??-)12(-COO)12] clusters that serve as hexagonal prismatic building blocks. In the absence of the sulfone groups, we discovered that the tetrahedral linker directs the formation of new RE-MOFs, RE-ken-MOF-1 (RE: Y3+, Ho3+, Er3+, Yb3+), that display an unprecedented (4, 8)-coordinated ken net based on nonanuclear RE9-clusters, to serve as bicapped trigonal prismatic building units. Successful activation of the representative member Y-ken-MOF-1 reveals a high BET surface area and total pore volume reaching 2621 m2 g-1 and 0.95 cm3 g-1, respectively. These values are the highest among all RE MOFs based on nonanuclear clusters and some of the highest in the entire RE family of MOFs. The present work uncovers a unique structural diversity existing between Zr/Hf and RE-based MOFs that demonstrates the crucial role of linker design. In addition, the discovery of the new RE-hpt-MOF-1 and RE-ken-MOF-1 families of MOFs highlights the great opportunities existing in RE-MOFs in terms of structural diversity that could lead to novel materials with new properties.

Full text of DOI:10.1021/jacs.0c07081

Subscriber access provided by CORNELL UNIVERSITY LIBRARY
Article
Remarkable Structural Diversity between Zr/Hf and Rare-
Earth MOFs via Ligand Functionalization and the Discovery
of Unique (4, 8)-c and (4, 12)-connected Frameworks
Giasemi K. Angeli, Danai Batzavali, Katerina Mavronassou, Constantinos
Tsangarakis, Tobias Stuerzer, Holger Ott, and Pantelis N. Trikalitis
J. Am. Chem. Soc., Just Accepted Manuscript • Publication Date (Web): 26 Aug 2020
Downloaded from pubs.acs.org on August 26, 2020
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 10
Journal of the American Chemical Society
1
2
3
4
5
6
7
8
9
Remarkable Structural Diversity between Zr/Hf and Rare-Earth
MOFs via Ligand Functionalization and the Discovery of
Unique (4, 8)-c and (4, 12)-connected Frameworks
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
Giasemi K. Angeli§, Danai Batzavali§, Katerina Mavronassou§, Constantinos Tsangarakis§, Tobias
Stuerzerǂ, Holger Ottǂ and Pantelis N. Trikalitis§,*
§ Department of Chemistry, University of Crete, Voutes 71003 Heraklion, Greece; ǂ Bruker AXS GmbH, Ostliche
Rheinbruckenstr 49, D-76187 Karlsruhe, Germany
ABSTRACT: Ligand modification in MOFs provides great opportunities not only for the development of functional materials with
new or enhanced properties but also for the discovery of novel structures. We report here that a sulfone functionalized tetrahedral
carboxylate-based ligand is capable in directing the formation of new and fascinating MOFs when combined with Zr4+/Hf4+ and
rare-earth metal cations (RE) with improved gas-sorption properties. In particular, the resulting M-flu-SO2 (M: Zr, Hf) materials
display a new type of the augmented flu-a net which is different compared to the flu-a framework formed by the non-functionalized
tetrahedral ligand. In terms of properties, a remarkable increase in the CO2 uptake is observed reaching 76.6 % and 61.6 % at 273 K
and 298 K and 1 bar, respectively. When combined with RE’s, the sulfone modified linker affords novel MOFs, RE-hpt-MOF-1
(RE: Y3+, Ho3+, Er3+), displaying a fascinating (4, 12)-coordinated hpt net, based on nonanuclear [RE9(μ3-Ο)2(μ3-ΟΗ)12(-COO)12]
clusters that serve as hexagonal prismatic building blocks. In the absence of the sulfone groups, we discovered that the tetrahedral
linker directs the formation of new RE-MOFs, RE-ken-MOF-1 (RE: Y3+, Ho3+, Er3+, Yb3+), displaying an unprecedented (4, 8)-
coordinated ken net based on nonanuclear RE9-clusters, serving as bicapped trigonal prismatic building units. Successful activation
of the representative member Y-ken-MOF-1 reveal a high BET surface area and total pore volume reaching 2621 m2 g-1 and 0.95
cm3 g-1, respectively. These values are the highest among all RE MOFs based on nonanuclear clusters and one of the highest in the
entire RE family of MOFs. The present work uncovers a unique structural diversity existing between Zr/Hf and RE-based MOFs
demonstrating the crucial role of linker design. In addition, the discovery of the new RE-hpt- MOF-1 and RE-ken-MOF-1 families
of MOFs, highlights the great opportunities existing in RE-MOFs in terms of structural diversity that could lead to novel materials
with new properties.
INTRODUCTION
The chemistry of metal-organic frameworks (MOFs) has
angles of adjacent rings as well as the relative positioning of
the coordinating groups, in order to fit into a particular
structure.17, 18 It is anticipated that for a given structure, there is
a limit in the degree of ligand deformation beyond of which
this structure will not be possible to form due to the associated
increased energetics.19 In cases where the inorganic building
block can accommodate various connectivities, as in the case
of Zr6O8 cluster, the system may find other stable
configurations to form, resulting in very different MOFs.17 In
fact, the rational design of geometrical modified or de-
symmetrized ligands and their use in exploratory MOF
synthesis is an excellent tool towards the discovery of novel
zirconium and rare-earth (RE)-based structures with important
properties.20-25
been enormously expanded during the last decade and unique
materials with remarkable structures and diverse properties
have been discovered.1-7 The systematic exploration and the
discovery of novel MOFs using diverse organic linkers and
metal clusters was greatly accelerated using the reticular
chemistry concept based on well-defined building blocks.8-12
The concept of building blocks in MOFs applies to both
the organic and inorganic parts of a given structure. However,
from a design point of view, it is important to note that in the
vast majority, the inorganic building blocks are formed in-situ
during MOF synthesis, under specific reaction conditions.10, 13,
14
This may impart noticeable limitations in MOF syntheses,
Along the above lines, ligand functionalization has been
applied as a strategy not only to impart new properties or
enhance existing ones in MOFs26, but also to alter the
symmetry and geometry of an organic ligand, providing in this
way further opportunities towards the discovery of new
structures.17, 23, 25, 27
because the particular synthetic conditions that lead to the
formation of a specific inorganic cluster or secondary building
block (SBU) need to be identified. On the other hand, the
organic linker could be considered, to an extent, as a true
building block because it maintains its integrity throughout the
reaction. However, in many cases of MOFs based on poly-
aromatic carboxylate linkers, a significant deformation of the
ligand is observed compared to its free state, indicating that
In the present work, we designed and synthesized the
sulfone (-SO2) functionalized derivative of the tetrahedral
ligand 4',4'',4''',4''''-methanetetrayltetrabiphenyl-4-carboxylic
acid (H4MTBC), denoted here as H4MTBC-SO2, as a novel
de-symmetrized building block towards the reticular synthesis
of new Zr/Hf and RE MOFs, with enhanced gas sorption
16
these are not rigid and robust building blocks.15, In other
words, frequently in MOFs, the organic linker adjusts its
geometrical characteristics, including bending and torsion
ACS Paragon Plus Environment

Journal of the American Chemical Society
Page 2 of 10
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 1. The structure of Zr-flu-SO2 looking slightly off the c-axis (a) and along the [111] direction (b). (c) The resulting flu-a net formed
by the 8-c inorganic and 4-c organic SBUs. The sphere highlights the pore space.
properties. We and others have demonstrated that the presence
of the polar –SO2 groups in MOFs increases the interaction
with polar gases such as CO2, resulting in a significantly
enhanced uptake and selectivity.28-32 The new H4MTBC-SO2
linker contains four –SO2 polar groups, each of which is
inserted through the formation of a five member ring in each
of the four biphenyl arms of the parent ligand (Figure 1c). The
formation of the five-member ring results in a reduction of
ligand flexibility because adjacent aromatic rings cannot rotate
and also, in a significant bending of each arm (the angle
between the central C-sp3 and the carbon atom of the
carboxylate group is ~160o), leading to a reduction of the
ligand symmetry from Td to S4.
The parent non-functionalized ligand, H4MTBC, has
been reported to form the augmented fluorite-type structure
(flu-a) with both Zr6O8 and Hf6O8 clusters, however with a
significant deformation, displaying D2d symmetry.33 Therefore,
in addition to the effect of –SO2 groups in the gas-sorption
properties, an important question is whether or not H4MTBC-
SO2 being more rigid and with different symmetry is capable
of forming isostructural flu-a type Zr- and Hf-based MOFs.
Remarkably, in both cases, highly crystalline MOFs were
isolated, denoted here as M-flu-SO2 (M: Zr, Hf), displaying
the flu-a topology but these are not isostructural compared to
PCN-521(Zr)/523(Hf), possessing significantly increased
space group symmetry, with a different pore size and shape. In
terms of properties, the presence of –SO2 groups was found to
greatly enhance the CO2 uptake.
The successful syntheses of M-flu-SO2 (M: Zr, Hf)
MOFs prompted us to explore the construction of RE-MOFs
based on the analogous hexanuclear RE6(μ3-OH)8 clusters and
H4MTBC-SO2 ligand. Remarkably, we discovered an
unprecedented family of (4, 12)-connected RE-MOFs, denoted
here as RE-hpt-MOF-1, based on 12-connected nonanuclear
clusters, [RE9(μ3-Ο)4(μ3-ΟΗ)12], displaying the novel hpt
topology. For comparison purposes, we explored the synthesis
of RE-MOFs using the non-functionalized ligand H4MTBC
and to a great surprise the new MOFs, denoted as RE-ken-
MOF-1, display a novel (4, 8)-connected structure with the
unique ken topology based on an unprecedented 8-connected,
bicapped
trigonal
prismatic
nonanuclear
cluster.
Representative members from each RE-MOF families have
been activated and selected gas-sorption properties are
presented and discussed.
RESULTS AND DISCUSSION
The solvothermal reaction between ZrCl4 and H4MTBC-
o
SO2 (H4L2) in N,N′-dimethylformamide (DMF) at 120 C for
12 h in the presence of benzoic acid acting as modulator,
resulted in the formation of high quality octahedral shaped,
ACS Paragon Plus Environment

Page 3 of 10
Journal of the American Chemical Society
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Figure 3. Carbon dioxide adsorption isotherms of Zr-flu-SO2 and
PCN-521 at the indicated temperatures up to 1 bar.
Figure 2. Argon sorption isotherms recorded at 87 K and the
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
corresponding DFT pore size distribution curves for Zr-flu-SO2
(blue data) and Hf-flu-SO2 (green data).
where in PCN-521 all clusters have the same relative
positioning (Figure S10). Therefore, Zr-flu-SO2 represents a
new type of (4, 8)-connected flu-a network. This kind of
polymorphism in MOFs is important because each member
provides distinct post synthetic functionalization opportunities
(linker and/or functional group insertion) due to the different
orientation of their inorganic SBU’s, as in the case of PCN-
70034 and Zr-bcu-azo33.35
To exclude the possibility of a potential solvent effect in
the formation of the different flu-a net types between Zr-flu-
SO2 and PCN-521, given that the former synthesized in DMF
while the later in DEF (N,N′-diethylformamide), we attempted
the synthesis of Zr-flu-SO2 in DEF instead of DMF. The
results show that Zr-flu-SO2 is also formed however, as a
powder-like solid with a poor crystallinity as confirmed by
PXRD (Figure S15), indicating that the formation of the new
type of flu-a net observed in Zr-flu-SO2 is associated with the
sulfone functionalized tetrahedral linker (H4L2).
The unit cell volume of Zr-flu-SO2 shows a 7.8 %
increase compared to PCN-521, with a 78 % solvent
accessible volume calculated by PLATON, which is almost
identical to PCN-521 (78.5%).33 The fact that the accessible
solvent volume is not reduced, despite the presence of sulfone
functional groups, is very interesting because both Zr-flu-SO2
and PCN-521 are made of similar in size building blocks
displaying the same (4, 8)-connectivity and attributed to the
pore geometry of Zr-flu-SO2 and the fact that the unit cell
volume is increased by 7.8 % compared to PCN-521.
Accordingly, the structure contains large polyhedral cavities
that are significantly more regular and wider than that in PCN-
521, in which an ellipsoid of approximately 14 x 19 Å can fit
(Figure 1 and S9). These cavities are interconnected through
smaller rhombic shaped windows of approximately 8 x 8 Å,
which along the c-axis are decorated with sulfone groups,
creating a 3D pore system that was found accessible, as
confirmed experimentally by accurate microporous analysis
using Ar at 87 K and described below (Figure 1).
The material is stable in H2O as well as in acidic (pH 1)
and basic aqueous solutions (pH 10) and in common organic
solvents including acetone, CH3CN and CH2Cl2, as confirmed
by PXRD (Figures S16 and S17). Activation of Zr-flu-SO2
was successfully achieved by applying a straightforward
procedure using acetone or dichloromethane as a volatile
solvent to exchange the original guest molecules followed by
overnight drying under vacuum at room temperature (see SI).
yellowish crystals suitable for single-crystal X-ray diffraction
(SCXRD) analysis (see SI). Accordingly, the material Zr-flu-
SO2 crystallizes in the tetragonal space group P42/mnm with
lattice parameters a = b = 24.6334(16) Å, c = 29.830(2) Å, V =
18101.(3) Å3. The structure consists of 8-connected [Zr6(μ3-
Ο)4(μ3-ΟΗ)4]12- clusters linked together by 4-connected
sulfone L24- ligands, resulting in a 3D (4, 8)-connected
framework displaying the flu-a topology, with an overall
charge
balanced
chemical
formula,
Zr6(μ3-Ο)4(μ3-
ΟΗ)4(OH)4(H2O)4(L2)2 (Figure 1). Phase purity was
confirmed by comparing the experiment powder X-ray
diffraction (PXRD) pattern with that calculated from the single
crystal structure (Figure S15).
In MOFs, for a given net based on a particular inorganic
building block, in this case the flu-a net based on Zr6-clusters
(D4h symmetry), the ligand needs to meet specific geometric
requirements.10, 12 Accordingly, as reported in PCN-521, the
formation of this particular flu-a net requires a significant
distortion of the ligand conformation and in particular, from Td
becomes D2d with angles 86.8o and 122o and at the same time,
adjacent phenyl rings are rotated 41.768o from each other to
meet the directionality of the 8-connected Zr6-clusters (Figure
S14).33 In marked contrast, in Zr-flu-SO2 the geometric
characteristics of the sulfone ligand are very different from the
ligand in PCN-521 (Figure S14). In particular, adjacent phenyl
rings are now locked in same plane due to the formation of a
five member ring upon insertion of the sulfone group and for
the same reason, each arm is highly bended with the angle
between the central C-sp3 and the carbon atom of the
carboxylate group reduced from 180o to 164.7o. Furthermore,
the angles between adjacent arms are 106.26o and 116.10o,
indicating a significantly less distortion, compared to the
ligand in PCN-521 (Figure S14). Therefore, it is quite
remarkable that the sulfone functionalized linker analogue,
H4L2, is still capable in forming the flu-a net and in fact, with
a significantly increased symmetry compared to PCN-521
(P42/mnm vs I4/m) and in addition, with a very different unit
cell size, pore shape and size, as we describe below. Looking
carefully the crystal structures of Zr-flu-SO2 and PCN-521,
this is achieved by changing the relative positioning of the Zr6-
clusters (Figure S10). In particular, in the unit cell of Zr-flu-
SO2 the central Zr6-cluster is rotated by 90o relative to those at
the corners,
ACS Paragon Plus Environment

Journal of the American Chemical Society
Page 4 of 10
The complete removal of all solvent molecules was confirmed
by
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. The structure of Y-hpt-MOF-1 looking down the [110] crystallographic direction (a) and the c-axis (b). (c) The novel hpt-a net
formed by the 12-c inorganic and 4-c organic SBUs. The spheres highlight the pore space.
1H NMR on a digested, activated sample (Figure S71). This is
also confirmed by thermogravimetric analysis (TGA) where
the material is stable up to 450 oC (Figure S74). Argon
sorption isotherm recorded at 87 K confirmed the permanent
porosity of Zr-flu-SO2, showing a steep uptake at low relative
pressures and in addition, a clearly visible condensation step
occurring between 0.05 – 0.1 p/po, indicating the presence of
small mesopores, in agreement with the crystallographic data
(Figure 2). Notably, this is contrast to PCN-521 where no
condensation step is visible in the corresponding isotherm
indicating that the accessible pores are smaller compared to
Zr-flu-SO2.33 The pore size distribution curve calculated using
Non-Local Density Functional Theory (NLDFT) after a
successful fitting of the Ar adsorption isotherm data using a
suitable NLDFT kernel, shows two main peaks centered at
14.2 Å and 18.7 Å, in full agreement with the crystallographic
data (Figure 2). The BET surface area, calculated in the
pressure range 0.01-0.05 p/po (below the condensation step)
using consistency criteria, is 2187 m2 g-1 (Figure S30) while
the total pore volume at 0.99 p/po is 0.87 cm3 g-1. The latter is
close to PCN-521 (1.1 cm3 g-1), however the surface area in
Zr-flu-SO2 is lower due to the presence of the small
mesopores.
to investigate its CO2 adsorption properties. For comparison
purposes we synthesized and successfully activated PCN-521,
for which its CO2 adsorption properties have not been
reported. The corresponding CO2 adsorption isotherms for
both MOFs recorded at 273 K and 298 K shown in Figure 3,
reveal a remarkable 76.6 % increase of CO2 uptake in Zr-flu-
SO2 at 273 K and 1 bar, compared to PCN-521, reaching 114.5
cm3 g-1 (5.11 mmol g-1). At 298 K the corresponding increase
is 61.6 %, reaching 74.7 cm3 g-1 (3.34 mmol g-1). The
0
calculated isosteric heat of adsorption at zero coverage (Qst )
using a virial type equation is 21.8 kJ mol-1 and 15 kJ mol-1 for
Zr-flu-SO2 and PCN-521, respectively (Figure S41-S43, S58-
S61).
0
Τhe observed 45 % increase in Qst , attributed to the
polar –SO2 groups in Zr-flu-SO2, correlates well with our
previously reported ab-initio calculations on a biphenyl-
dicarboxylate linker, revealing that the increase in CO2
binding strength due to the insertion of a –SO2 group is
0
approximately 30 %.30 The observed Qst in Zr-flu-SO2 is
lower compared to that reported for the sulfone functionalized
Zr-UiO-67 (26.5 kJ mol-1) presumably due to the increased
pore size in Zr-flu-SO2 causing a reduction in the overlapping
potential between opposite walls that in turns, reduce the CO2-
framework interactions.30
The large accessible pore volume in Zr-flu-SO2 in
combination with the polarizing sulfone groups, prompted us
ACS Paragon Plus Environment

Page 5 of 10
Journal of the American Chemical Society
The isostructural Hf-flu-SO2 was successfully
(Figure S20). Topological analysis of the obtained crystal
structure revealed a new fascinating topology, denoted here as
hpt, where the nonanuclear cluster serves as a 12-c hexagonal
prismatic building block (double six-membered ring, d6R) and
the sulfone linker as a 4-c tetrahedral node, forming an
unprecedented (4, 12)-c net with a point symbol of
{433.630.83}{46}3 as determined by ToposPro39 (Figure 4). To
the best of our knowledge, the novel RE-hpt-MOF-1 (RE:
Y3+, Er3+, Ho3+) materials represent the first examples in which
the 12-c d6R nonanuclear [RE9(μ3-Ο)2(μ3-ΟΗ)12]11- clusters are
combined with a 4-c rigid tetrahedral linker. Interestingly,
looking at the top and the bottom of the nonanuclear cluster,
the dihedral angles of the coordinated carboxylate groups are
different and from one side is 158.2o while from the other is
173.3o (Figure S11). This particular connectivity of the d6R
clusters results in the formation of two different polyhedral
cavities in Y-hpt-MOF-1 stacked one on the top of the other,
along the c-axis (Figure 4 and S11). In particular, the large
cavity consists of 8 d6R clusters and 12 linkers and has an
ellipsoid shape of approximately 20x30 Å, taking the distances
from opposite clusters, while the smaller one, with a more
symmetric rhombic shape of 10x12 Å cavity is made of two 2
d6R clusters and 6 linkers (Figure S11). These cavities are
interconnected via rectangular windows forming a complex
3D pore system (Figure 4). Regarding the geometric
configuration of the sulfone linker, this is more distorted
compared to M-flu-SO2 (M: Zr, Hf) MOFs with the angles
between adjacent arms found in the range 95.84o-131.1o
(Figure S14).
1
synthesized in a single-crystal form and fully characterized
(see SI). This material is also stable in H2O as well as in acidic
(pH 1) and basic aqueous solutions (pH 10) and in common
organic solvents including acetone and CH2Cl2, as confirmed
by PXRD (Figures S18 and S19). The corresponding Ar
isotherm recorded at 87 K on an activated sample displays the
same shape observed in Zr-flu-SO2 showing a distinct
condensation step (Figure 2). The corresponding NLDFT pore
distribution is identical to the Zr-analogue (Figure 2). The
BET surface area is 1895 m2 g-1 and the total pore volume at
0.99 p/po is 0.78 cm3 g-1 (Figures 1 and S32). The
corresponding CO2 isotherms recorded at 273 K and 298 K at
1 bar, reveal a high uptake reaching 85.1 cm3 g-1 and 49.3 cm3
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
g-1 respectively, with a Qst of 24 kJ mol-1 (Figure S44-S46).
0
0
The increased Qst in Hf-flu-SO2 as compared to Zr-flu-SO2
could be attributed to the more acidic nature of the Hf6-cluster,
as it has been reported for other MOFs including NUS-
6(Zr/Hf)36 and VPI-100(Zr/Hf).37 The observed reduced
gravimetric BET surface area and CO2 uptake is due to fact
that Hf-flu-SO2 is heavier than Zr-flu-SO2.
For both Zr-flu-SO2 and Hf-flu-SO2 solids, in addition to
CO2, we measured the corresponding CH4 sorption isotherms,
0
from which the Qst and IAST CO2/CH4 selectivity were
0
calculated (Figure S49-51, S53-55). Accordingly, the Qst
value is 16 kJ mol-1 and 22 kJ mol-1 for Zr-flu-SO2 and Hf-flu-
SO2 respectively, while the corresponding CO2/CH4 selectivity
at 273 K and 298 K using the IAST methodology for a 5/95
molar mixture is 13.1/9.0 and 9.5/8.5 (Figure S56-57).
Notably, in the case of Zr-flu-SO2, the observed CO2/CH4
selectivity is higher compared to the sulfone functionalized Zr-
UiO-67 (9.8/6.8), recorded under the same experimental
conditions.30
The successful synthesis of M-flu-SO2 (M: Zr, Hf)
MOFs prompted us to investigate the synthesis of the
corresponding rare-earth (RE) analogues, given the existence
of the hexanuclear [RE6(μ3-ΟΗ)8]10+ clusters.38 The synthesis
protocol was modified because the formation of RE-clusters in
most cases requires the use of 2-fluorobenzoic acid (2-FBA)
as modulator. However, in our case we found that a mixed
modulator system, using also an excess of acetic acid, is
crucial in obtaining high quality crystalline materials (see SI).
Accordingly, solvothermal reactions in DMF between
RE(NO3)3·6H2O (RE: Y3+, Ho3+ and Er3+) and H4L2 in the
presence of excess acetic acid and 2-FBA, afforded high
quality polyhedral shaped single crystals. Based on SCXRD
(Table S4-S6) and PXRD (Figure S20) analyses, these
materials are isostructural and therefore only the structure of
the Yttrium analogue is described below.
Nitrogen sorption measurements on an activated Y-hpt-
MOF-1 revealed a type-I isotherm with a total pore volume of
0.25 cm3 g-1 at 0.99 p/po which is lower compared to the
calculated value from the single crystal structure (1.1 cm3 g-1),
indicating a partial activation (Figure S35). This is also
reflected in the pore size distribution curve obtained from an
Argon sorption isotherm at 87 K, were a main peak centered at
around 6 Å is observed (Figure S36 and S37). However, CO2
adsorption measurements at 273 K, 283 K and 298 K revealed
a high uptake, reaching 119.8 cm3 g-1, 109.6 cm3 g-1 and 96.5
cm3 g-1 respectively at 1 bar, which is higher compared to Zr-
flu-SO2 at the same conditions (114.5 cm3 g-1 and 74.7 cm3 g-1
at 273 K and 298 K) (Figure S62). The corresponding isosteric
heat of adsorption at zero coverage is 22.2 kJ mol-1 which is
higher compared to Zr-flu-SO2 (21.8 kJ mol-1) and supports
the observed higher CO2 uptake of the former (Figure S64).
The enhanced CO2 uptake in Y-hpt-MOF-1 is attributed to the
increased density of the polar –SO2 groups by 23.1 % (based
on the number of –SO2 groups per unit cell volume) and the
ionic nature of the material that increases the CO2-framework
The material, denoted here as Y-hpt-MOF-1, crystallizes
in the hexagonal system, space group R-3m, with unit cell, a =
b = 39.5393(14) Å, c = 48.8586(19) Å, V = 66150 (5) Å3. The
structure consists of ordered 12-connected nonanuclear
clusters, [Υ9(μ3-Ο)2(μ3-ΟΗ)12(-COO)12], linked together by 4-
connected sulfone L24- ligands, resulting in a novel 3D (4,
12)-connected structure with an overall chemical formula,
[(CH3)2NH2]3[Y9(μ3-Ο)2(μ3-ΟΗ)12(Ac)2(H2O)3(L2)3] (Figure
4). In addition to charge balance considerations, the presence
of counterions was confirmed in a sodium exchanged analogue
using a SEM/EDS, where the Na:RE was found to be very
close to 1:3 as expected (Figure S28-S29 and Table S9). Phase
purity was confirmed by comparing the experimental PXRD
pattern with that calculated from the single crystal structure
interactions, presumably via
mechanism.
a
dipole-induce dipole
An important question is whether or not the formation of
the fascinating structure of RE-hpt-MOF-1 is associated with
the sulfone functionalized linker displaying the S4 symmetry.
To answer this question, we targeted the synthesis of RE-
MOFs based on the tetrahedral non-functionalized linker
H4MTBC (H4L). Accordingly, using Y(NO3)3·6H2O and
following a very similar synthetic procedure but adjusting the
molar ratio of the modulators (acetic acid and 2-FBA), high
quality hexagonal crystals were obtained (Figure S8). Under
the same reaction conditions, we obtained isostructural
analogues as confirmed by SXCRD and PXRD, denoted here
ACS Paragon Plus Environment

Journal of the American Chemical Society
as RE-ken-MOF-1 (RE: Y3+, Ho3+, Er3+, Yb3+) and below the
Page 6 of 10
1
2
3
4
5
6
7
8
structure of Y-ken-MOF-1 is described in detail (Figure S24).
Remarkably, SCXRD analysis of Y-ken-MOF-1
revealed the formation of a novel structure that crystallizes in
the trigonal system, space group P-31c, with unit cell a = b =
25.4495(5) Å, c = 39.5438(8) Å, V = 22180.3 (10) Å3 made of
8-connected nonanuclear clusters, [Y9(μ3-Ο)2(μ3-ΟΗ)12(-
COO)8], bridged together by 4-c tetrahedral linkers that
preserves their Td symmetry (Figure 5 and Table S7). In
particular, eight carboxylate groups from eight different 4-c
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 5. The structure of Y-ken-MOF-1 looking down the b-axis (a) and the c-axis (b). (c) The novel ken-a net formed by the 8-c
inorganic and 4-c organic SBUs. The yellow spheres highlight the pore space.
tetrahedral linkers are coordinated to Y9-clusters in a bicapped
trigonal prismatic fashion (Figure 5). Interestingly, along the
c-axis, pairs of opposite linkers are formed and connect six Y9-
clusters in a regular trigonal prismatic arrangement (Figure 5
and S13). Each Y9-cluster is connected to twelve other Y9-
clusters, six in equatorial position via three pairs of linkers and
six more, three on the top and three on the bottom, via two
more linkers (Figure S13). This is an unprecedented
connectivity and the analysis using ToposPro39 revealed the
formation of the ken topology as registered in the RCSR
database,40 where the 8-c Y9-clusters serve as bicapped
trigonal prismatic building blocks bridged via the 4-c Td
linkers to form a unique (4, 8)-c net with point symbol
{46}2{49.618.8} (Figure 5). In the crystal structure the Y9-
clusters are found disordered over two positions as it has been
observed in other cases of RE-MOFs based on nonanuclear
clusters, including Y-kce-MOF-141, Y-shp-MOF-142 and Y-
The structure of Y-ken-MOF-1 contains 1D hexagonal
pores of approximately 15 Å in diameter running along the c-
axis and these are connected to each other via 9x9 Å rhombic
shaped windows, running along the a- and b-axis, creating an
interconnected 3D pore system (Figure 5). The solvent
accessible volume calculated by PLATON is 75 % and found
to be accessible by gas sorption measurements on an activated
material. In particular, Argon sorption measurements at 87 K
revealed a fully reversible type I isotherm displaying a high
uptake, reaching 744 cm3 g-1 at p/p0 0.98, which corresponds
to a total pore volume of 0.95 cm3 g-1 (Figure 6). It is noted
that the experimental total pore volume is half of what is
expected from the single crystal structure (1.86 cm3 g-1),
indicating a partial activation. The fact that the experimental
pore size distribution (PSD) matches very well the expected
values from the single crystal structure, as we describe below,
suggests that some of the pores in Y-ken-MOF-1 are
inaccessible presumably due to the presence of residual ligand
and/or metal oxide clusters. This proposition is supported by
thermogravimetric analysis (TGA) and infrared spectroscopy
(Figure S75 and S76). The BET equation was applied
successfully in the p/po range 0.015-0.047 using consistency
criteria, revealing a high surface area of 2621 m2 g-1
1
shp-MOF-543 (Figure S12). Careful analysis using H NMR
in an acid digested material and SEM/EDS in a sodium
exchanged sample, revealed that the framework is neutral with
a
charged balanced chemical formula, Y9(μ3-Ο)2(μ3-
ΟΗ)12(OH)2(H2O)11L2 (Figure S27, S73 and Table S8).
ACS Paragon Plus Environment

Page 7 of 10
Journal of the American Chemical Society
(Langmuir 2879 m2 g-1) (Figure S38). The observed BET
similar 1D hexagonal pore system (3.37 and 1.94 mmol g-1 at
0
273 K and 298 K, respectively).49 However, Qst is
1
2
3
4
5
6
7
8
surface area and total pore volume of Y-ken-MOF-1 is the
highest among all reported MOFs based on nonanuclear RE9-
clusters including Y-kex-MOF-141 (1580 m2 g-1, 0.84 cm3 g-1),
Y-shp-MOF-142 (2200 m2 g-1, 0.84 cm3 g-1), Y-pek-MOF-144
(1608 m2 g-1, 0.58 cm3 g-1), Y-aea-MOF-144 (1435 m2 g-1, 0.49
cm3 g-1) and among the highest in the entire RE-based family
of MOFs25, 27, 45-47 (Table S10). The PSD curve obtained by
applying a suitable NLDFT kernel shows two peaks at 9.5 Å
and 14 Å, very close to the crystallographic pore sizes (Figure
S40). The gas sorption properties of Y-ken-MOF-1 were
further explored by recording CH4, CO2 and Xe sorption
isotherms at different temperatures. The CH4 isotherm
recorded at its boiling point (112 K) resembles that of Ar at 87
K, revealing a total pore volume of 0.95 cm3 g-1, in full
agreement with the Ar data (Figure 6). Interestingly, the CO2
isotherm at 195 K shows an almost linear increase in the
uptake up to 250 torr forming thereafter a plateau, reaching
563.2 cm3 g-1 at 0.99 p/p0 (total pore volume, 0.88 cm3 g-1) and
attributed to the particular pore size and structure of Y-ken-
MOF-1 (Figure 6). The isosteric heat of adsorption was
calculated using the CO2 isotherms at 273 K (uptake 85.1 cm3
g-1 at
significantly reduced in Y-ken-MOF-1 (22.3 vs 33.8 kJ mol-1
in Y-csq-MOF-1), which is preferable for Xe storage
applications, due to the associated reduced energy demand for
Xe delivery.
CONCLUSIONS
In conclusion, we report a rare case where ligand
functionalization has a remarkable effect in the final structure
when combined with Zr/Hf and RE-metal cations and led to
the discovery of novel MOFs. The sulfone functionalized
tetrahedral ligand H4MTBC-SO2 with Zr/Hf affords new
MOFs, M-flu-SO2 (M: Zr, Hf), based on the corresponding
hexanuclear clusters with flu-a topology which are not
isostructural with the analogous MOFs (PCN-521 and PCN-
523) based on the non-functionalized tetrahedral ligand,
displaying a different type of the flu-a net. Highly unusual is
the fact the M-flu-SO2 (M: Zr, Hf) display larger pores, in the
mesopore range, compared to PCN-521/523 despite the
presence of –SO2 groups. These polar groups in combination
with the particular pore structure results in a remarkable
enhancement of CO2 adsorption uptake in M-flu-SO2 (M: Zr,
Hf). The H4MTBC-SO2 ligand when combined with RE’s
afforded a novel family of MOFs based on nonanuclear RE9-
clusters, RE-hpt-MOF-1, displaying an unprecedented (4, 12)-
connected network. The corresponding structure contains two
different polyhedral cavities and the Y-analogue, although was
partially activated, shows a higher CO2 uptake compared to
Zr-flu-SO2 under the same conditions. Finally, in an effort to
understand the role of this particular sulfone linker in directing
the structure of RE-hpt-MOF-1, we discovered that the parent
non-functionalized H4MTBC ligand with RE’s directs the
formation of novel (4, 8)-connected MOFs, RE-ken-MOF-1.
These RE-MOFs are neutral, based on a unique 8-connected
nonanuclear RE9-cluster that serves as a bicapped trigonal
prismatic building unit and features large hexagonal channels.
The Y-ken-MOF-1 analogue was successfully activated and
shows a very high BET area and pore volume. The discovery
of the new RE families of MOFs, RE-hpt-MOF-1 and RE-
ken-MOF-1, demonstrates the great opportunities existing in
RE-MOFs in terms of structural diversity, that could lead to
novel MOFs with new properties. In particular, the structure of
RE-ken-MOF-1 is an excellent platform for isoreticular
expansion, using elongated tetrahedral linkers, towards highly
porous RE-MOFs and we are currently working on this
direction.
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. Ar (blue), CH4 (green) and CO2 (red) sorption
isotherms in linear and semi logarithmic scale (inset) of Y-ken-
MOF-1 recorder at their boiling point temperature. Closed
symbols represent adsorption and open symbols desorption.
1 bar) and 298 K (uptake 37.8 cm3 g-1 at 1 bar) and found to be
20.3 kJ mol-1 at zero coverage (Qst ) and remains constant as a
0
function of surface coverage, indicating an energetically
ASSOCIATED CONTENT
0
uniform pore environment (Figure S65-S67). The lower Qst
compare to the Y-hpt-MOF-1 (22.2 kJ mol-1) is consistent
with the observed lower CO2 uptake (Figure S65).
Experimental details, single crystal and powder XRD data, EDS,
gas sorption isotherms and related calculations, NMR and TGA.
This material is available free of charge via the Internet at
http://pubs.acs.org.
Finally, because Xe storage48 in porous materials is
considered an important application and the combination of
high surface area and high pore volume plays a key role, we
examined the Xe adsorption properties of Y-ken-MOF-1 at
different temperatures. The corresponding isotherms recorded
at 240 K, 273 K and 298 K reveal an uptake of 166.4 cm3 g-1
(7.4 mmol g-1), 88.8 cm3 g-1 (3.9 mmol g-1) and 39.8 cm3 g-1
AUTHOR INFORMATION
Corresponding Author
* ptrikal@uoc.gr
0
(1.8 mmol g-1) respectively, with a Qst of 22.3 kJ mol-1
ACKNOWLEDGMENT
(Figure S68-S70). Although these are moderate values
compared to the state-of-the-art Xe storage MOFs displaying a
high density of unsaturated metal sites48, the observed uptake
is very similar to that reported for Y-csq-MOF-1 exhibiting a
This research has been co‐financed by the European Regional
Development Fund of the European Union and Greek national
funds through the Operational Program Competitiveness,
ACS Paragon Plus Environment

Journal of the American Chemical Society
Page 8 of 10
UH3-like Topology Based on Elongated Tetrahedral Linkers. J. Am.
Chem. Soc. 2016, 138 (27), 8380-8383.
Entrepreneurship and Innovation, under the call RESEARCH –
CREATE – INNOVATE (project code:T1EDK-00770).
1
2
3
4
5
6
7
8
(19) Zhang, Y.-B.; Furukawa, H.; Ko, N.; Nie, W.; Park, H. J.;
Okajima, S.; Cordova, K. E.; Deng, H.; Kim, J.; Yaghi, O. M.,
Introduction of Functionality, Selection of Topology, and
Enhancement of Gas Adsorption in Multivariate Metal–Organic
Framework-177. J. Am. Chem. Soc. 2015, 137 (7), 2641-2650.
(20) Ma, J. L.; Tran, L. D.; Matzger, A. J., Toward Topology
Prediction in Zr-Based Microporous Coordination Polymers: The
Role of Linker Geometry and Flexibility. Cryst. Growth Des. 2016,
16 (7), 4148-4153.
(21) Wang, Y.; Feng, L.; Zhang, K.; Wang, K.-Y.; Fan, W.;
Wang, X.; Guo, B.; Dai, F.; Zhang, L.; Sun, D.; Zhou, H.-C.,
Uncovering Structural Opportunities for Zirconium Metal–Organic
Frameworks via Linker Desymmetrization. Adv. Sci. 2019, 6 (23),
1901855.
(22) Ortín-Rubio, B.; Ghasempour, H.; Guillerm, V.; Morsali, A.;
Juanhuix, J.; Imaz, I.; Maspoch, D., Net-Clipping: An Approach to
Deduce the Topology of Metal–Organic Frameworks Built with
Zigzag Ligands. J. Am. Chem. Soc. 2020, 142 (20), 9135-9140.
(23) Guillerm, V.; Maspoch, D., Geometry Mismatch and Reticular
Chemistry: Strategies To Assemble Metal–Organic Frameworks with
Non-default Topologies. J. Am. Chem. Soc. 2019, 141 (42), 16517-
16538.
(24) Wang, H.; Dong, X.; Lin, J.; Teat, S. J.; Jensen, S.; Cure,
J.; Alexandrov, E. V.; Xia, Q.; Tan, K.; Wang, Q.; Olson, D. H.;
Proserpio, D. M.; Chabal, Y. J.; Thonhauser, T.; Sun, J.; Han, Y.;
Li, J., Topologically guided tuning of Zr-MOF pore structures for
highly selective separation of C6 alkane isomers. Nat. Commun. 2018,
9 (1), 1745.
(25) Feng, L.; Wang, Y.; Zhang, K.; Wang, K.-Y.; Fan, W.;
Wang, X.; Powell, J. A.; Guo, B.; Dai, F.; Zhang, L.; Wang, R.;
Sun, D.; Zhou, H.-C., Molecular Pivot-Hinge Installation to Evolve
Topology in Rare-Earth Metal–Organic Frameworks. Angew. Chem.
Int. Ed. 2019, 58 (46), 16682-16690.
(26) Jiang, H.; Zhang, W. Q.; Kang, X.; Cao, Z. P.; Chen, X.;
Liu, Y.; Cui, Y., Topology-Based Functionalization of Robust Chiral
Zr-Based Metal-Organic Frameworks for Catalytic Enantioselective
Hydrogenation. J. Am. Chem. Soc. 2020, 142 (21), 9642-9652.
(27) Wang, Y. T.; Feng, L.; Fan, W. D.; Wang, K. Y.; Wang, X.;
Wang, X. K.; Zhang, K.; Zhang, X. R.; Dai, F. N.; Sun, D. F.;
Zhou, H. C., Topology Exploration in Highly Connected Rare-Earth
Metal-Organic Frameworks via Continuous Hindrance Control. J.
Am. Chem. Soc. 2019, 141 (17), 6967-6975.
(28) Chakraborty, G.; Das, P.; Mandal, S. K., Polar Sulfone-
Functionalized Oxygen-Rich Metal–Organic Frameworks for Highly
Selective CO2 Capture and Sensitive Detection of Acetylacetone at
ppb Level. ACS Appl. Mater. Interfaces 2020, 12 (10), 11724-11736.
(29) Wang, B.; Huang, H.; Lv, X.-L.; Xie, Y.; Li, M.; Li, J.-R.,
Tuning CO2 Selective Adsorption over N2 and CH4 in UiO-67
Analogues through Ligand Functionalization. Inorg. Chem. 2014, 53
(17), 9254-9259.
(30) Xydias, P.; Spanopoulos, I.; Klontzas, E.; Froudakis, G. E.;
Trikalitis, P. N., Drastic Enhancement of the CO2 Adsorption
Properties in Sulfone-Functionalized Zr- and Hf-UiO-67 MOFs with
Hierarchical Mesopores. Inorg. Chem. 2014, 53 (2), 679-681.
(31) Couck, S.; Liu, Y.-Y.; Leus, K.; Baron, G. V.; Van der
Voort, P.; Denayer, J. F. M., Gas phase adsorption of alkanes, alkenes
and aromatics on the sulfone-DUT-5 Metal Organic Framework.
Microporous Mesoporous Mater. 2015, 206, 217-225.
REFERENCES
(1) Furukawa, H.; Cordova, K. E.; O'Keeffe, M.; Yaghi, O. M.,
The Chemistry and Applications of Metal-Organic Frameworks.
Science 2013, 341 (6149), 974.
(2) Bennett, T. D.; Cheetham, A. K.; Fuchs, A. H.; Coudert, F.-X.,
Interplay between defects, disorder and flexibility in metal-organic
frameworks. Nat. Chem. 2017, 9 (1), 11-16.
(3) Foo, M. L.; Matsuda, R.; Kitagawa, S., Functional Hybrid
Porous Coordination Polymers. Chem. Mater. 2014, 26 (1), 310-322.
(4) Hendon, C. H.; Rieth, A. J.; Korzyński, M. D.; Dincă, M.,
Grand Challenges and Future Opportunities for Metal–Organic
Frameworks. ACS Cent. Sci. 2017, 3 (6), 554-563.
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
(5) Coudert, F.-X.; Evans, J. D., Nanoscale metamaterials: Meta-
MOFs and framework materials with anomalous behavior. Coord.
Chem. Rev. 2019, 388, 48-62.
(6) Ding, M. L.; Flaig, R. W.; Jiang, H. L.; Yaghi, O. M., Carbon
capture and conversion using metal-organic frameworks and MOF-
based materials. Chem. Soc. Rev. 2019, 48 (10), 2783-2828.
(7) Zhang, L. L.; Yuan, S.; Feng, L.; Guo, B. B.; Qin, J. S.; Xu,
B.; Lollar, C.; Sun, D. F.; Zhou, H. C., Pore-Environment
Engineering with Multiple Metal Sites in Rare-Earth Porphyrinic
Metal-Organic Frameworks. Angew. Chem. Int. Ed. 2018, 57 (18),
5095-5099.
(8) Alezi, D.; Spanopoulos, I.; Tsangarakis, C.; Shkurenko, A.;
Adil, K.; Belmabkhout, Y.; O'Keeffe, M.; Eddaoudi, M.; Trikalitis,
P. N., Reticular Chemistry at Its Best: Directed Assembly of
Hexagonal Building Units into the Awaited Metal-Organic
Framework with the Intricate Polybenzene Topology, pbz-MOF. J.
Am. Chem. Soc. 2016, 138 (39), 12767-12770.
(9) Chen, Z.; Hanna, S. L.; Redfern, L. R.; Alezi, D.; Islamoglu,
T.; Farha, O. K., Reticular chemistry in the rational synthesis of
functional zirconium cluster-based MOFs. Coord. Chem. Rev. 2019,
386, 32-49.
(10) Kalmutzki, M. J.; Hanikel, N.; Yaghi, O. M., Secondary
building units as the turning point in the development of the reticular
chemistry of MOFs. Sci. Adv. 2018, 4, No. eaat9180.
(11) Yaghi, O. M.; O'Keeffe, M.; Ockwig, N. W.; Chae, H. K.;
Eddaoudi, M.; Kim, J., Reticular synthesis and the design of new
materials. Nature 2003, 423 (6941), 705-714.
(12) Yaghi, O. M.; Kalmutzki, M. J.; Diercks, C. S., Introduction
to Reticular Chemistry. Wiley 2019.
(13) Alezi, D.; Belmabkhout, Y.; Suyetin, M.; Bhatt, P. M.;
Weseliński, Ł. J.; Solovyeva, V.; Adil, K.; Spanopoulos, I.;
Trikalitis, P. N.; Emwas, A.-H.; Eddaoudi, M., MOF Crystal
Chemistry Paving the Way to Gas Storage Needs: Aluminum-Based
soc-MOF for CH4, O2, and CO2 Storage. J. Am. Chem. Soc. 2015,
137 (41), 13308-13318.
(14) Guillerm, V.; Kim, D.; Eubank, J. F.; Luebke, R.; Liu, X.;
Adil, K.; Lah, M. S.; Eddaoudi, M., A supermolecular building
approach for the design and construction of metal–organic
frameworks. Chem. Soc. Rev. 2014, 43 (16), 6141-6172.
(15) Lv, X.-L.; Yuan, S.; Xie, L.-H.; Darke, H. F.; Chen, Y.;
He, T.; Dong, C.; Wang, B.; Zhang, Y.-Z.; Li, J.-R.; Zhou, H.-C.,
Ligand Rigidification for Enhancing the Stability of Metal–Organic
Frameworks. J. Am. Chem. Soc. 2019, 141 (26), 10283-10293.
(16) Zhang, X.; Frey, B. L.; Chen, Y.-S.; Zhang, J., Topology-
Guided Stepwise Insertion of Three Secondary Linkers in Zirconium
Metal–Organic Frameworks. J. Am. Chem. Soc. 2018, 140 (24), 7710-
7715.
(32) Wang, G.; Leus, K.; Couck, S.; Tack, P.; Depauw, H.; Liu,
Y.-Y.; Vincze, L.; Denayer, J. F. M.; Van Der Voort, P., Enhanced
gas sorption and breathing properties of the new sulfone
functionalized COMOC-2 metal organic framework. Dalton Trans.
2016, 45 (23), 9485-9491.
(33) Zhang, M. W.; Chen, Y. P.; Bosch, M.; Gentle, T.; Wang,
K. C.; Feng, D. W.; Wang, Z. Y. U.; Zhou, H. C., Symmetry-Guided
Synthesis of Highly Porous Metal-Organic Frameworks with Fluorite
Topology. Angew. Chem. Int. Ed. 2014, 53 (3), 815-818.
(17) Lyu, J.; Zhang, X.; Otake, K.-i.; Wang, X.; Li, P.; Li, Z.;
Chen, Z.; Zhang, Y.; Wasson, M. C.; Yang, Y.; Bai, P.; Guo, X.;
Islamoglu, T.; Farha, O. K., Topology and porosity control of metal–
organic frameworks through linker functionalization. Chem. Sci.
2019, 10 (4), 1186-1192.
(18) Zhang, X.; Zhang, X.; Johnson, J. A.; Chen, Y.-S.; Zhang,
J., Highly Porous Zirconium Metal–Organic Frameworks with β-
(34) Yuan, S.; Lu, W.; Chen, Y.-P.; Zhang, Q.; Liu, T.-F.; Feng,
D.; Wang, X.; Qin, J.; Zhou, H.-C., Sequential Linker Installation:
ACS Paragon Plus Environment

Page 9 of 10
Journal of the American Chemical Society
Precise Placement of Functional Groups in Multivariate Metal–
Organic Frameworks with csq Topology Based on RE4(μ3-
O)2(COO)8 Clusters. ACS Appl. Mater. Interfaces 2017, 9 (51),
44560-44566.
Organic Frameworks. J. Am. Chem. Soc. 2015, 137 (9), 3177-3180.
(35) Guillerm, V.; Grancha, T.; Imaz, I.; Juanhuix, J.; Maspoch,
D., Zigzag Ligands for Transversal Design in Reticular Chemistry:
Unveiling New Structural Opportunities for Metal–Organic
Frameworks. J. Am. Chem. Soc. 2018, 140 (32), 10153-10157.
(36) Hu, Z. G.; Peng, Y. W.; Gao, Y. J.; Qian, Y. H.; Ying, S.
M.; Yuan, D. Q.; Horike, S.; Ogiwara, N.; Babarao, R.; Wang, Y.
X.; Yan, N.; Zhao, D., Direct Synthesis of Hierarchically Porous
Metal-Organic Frameworks with High Stability and Strong Bronsted
Acidity: The Decisive Role of Hafnium in Efficient and Selective
Fructose Dehydration. Chem. Mater. 2016, 28 (8), 2659-2667.
(37) Zhu, J.; Liu, J.; Machain, Y.; Bonnett, B.; Lin, S.; Cai, M.;
Kessinger, M. C.; Usov, P. M.; Xu, W.; Senanayake, S. D.; Troya,
D.; Esker, A. R.; Morris, A. J., Insights into CO2 adsorption and
chemical fixation properties of VPI-100 metal–organic frameworks.
Journal of Materials Chemistry A 2018, 6 (44), 22195-22203.
(38) Xue, D.-X.; Cairns, A. J.; Belmabkhout, Y.; Wojtas, L.;
Liu, Y.; Alkordi, M. H.; Eddaoudi, M., Tunable Rare-Earth fcu-
MOFs: A Platform for Systematic Enhancement of CO2 Adsorption
Energetics and Uptake. J. Am. Chem. Soc. 2013, 135 (20), 7660-7667.
(39) Blatov, V. A.; Shevchenko, A. P.; Proserpio, D. M., Applied
Topological Analysis of Crystal Structures with the Program Package
ToposPro. Cryst. Growth Des. 2014, 14 (7), 3576-3586.
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
(40) O’Keeffe, M.; Peskov, M. A.; Ramsden, S. J.; Yaghi, O. M.,
The Reticular Chemistry Structure Resource (RCSR) Database of, and
Symbols for, Crystal Nets. Acc. Chem. Res. 2008, 41 (12), 1782-1789.
(41) Chen, Z.; Thiam, Z.; Shkurenko, A.; Weselinski, L. J.; Adil,
K.; Jiang, H.; Alezi, D.; Assen, A. H.; O’Keeffe, M.; Eddaoudi, M.,
Enriching the Reticular Chemistry Repertoire with Minimal Edge-
Transitive Related Nets: Access to Highly Coordinated Metal–
Organic Frameworks Based on Double Six-Membered Rings as Net-
Coded Building Units. J. Am. Chem. Soc. 2019, 141 (51), 20480-
20489.
(42) Chen, Z.; Weseliński, Ł. J.; Adil, K.; Belmabkhout, Y.;
Shkurenko, A.; Jiang, H.; Bhatt, P. M.; Guillerm, V.; Dauzon, E.;
Xue, D.-X.; O’Keeffe, M.; Eddaoudi, M., Applying the Power of
Reticular Chemistry to Finding the Missing alb-MOF Platform Based
on the (6,12)-Coordinated Edge-Transitive Net. J. Am. Chem. Soc.
2017, 139 (8), 3265-3274.
(43) AbdulHalim, R. G.; Bhatt, P. M.; Belmabkhout, Y.;
Shkurenko, A.; Adil, K.; Barbour, L. J.; Eddaoudi, M., A Fine-
Tuned Metal–Organic Framework for Autonomous Indoor Moisture
Control. J. Am. Chem. Soc. 2017, 139 (31), 10715-10722.
(44) Alezi, D.; Peedikakkal, A. M. P.; Weseliński, Ł. J.;
Guillerm, V.; Belmabkhout, Y.; Cairns, A. J.; Chen, Z.; Wojtas, Ł.;
Eddaoudi, M., Quest for Highly Connected Metal–Organic
Framework Platforms: Rare-Earth Polynuclear Clusters Versatility
Meets Net Topology Needs. J. Am. Chem. Soc. 2015, 137 (16), 5421-
5430.
(45) Luebke, R.; Belmabkhout, Y.; Weselinski, L. J.; Cairns, A.
J.; Alkordi, M.; Norton, G.; Wojtas, L.; Adil, K.; Eddaoudi, M.,
Versatile rare earth hexanuclear clusters for the design and synthesis
of highly-connected ftw-MOFs. Chem. Sci. 2015, 6 (7), 4095-4102.
(46) Luo, T.-Y.; Liu, C.; Eliseeva, S. V.; Muldoon, P. F.; Petoud,
S.; Rosi, N. L., Rare Earth pcu Metal–Organic Framework Platform
Based on RE4(μ3-OH)4(COO)62+ Clusters: Rational Design,
Directed Synthesis, and Deliberate Tuning of Excitation Wavelengths.
J. Am. Chem. Soc. 2017, 139 (27), 9333-9340.
(47) Li, Y.-J.; Wang, Y.-L.; Liu, Q.-Y., The Highly Connected
MOFs Constructed from Nonanuclear and Trinuclear Lanthanide-
Carboxylate Clusters: Selective Gas Adsorption and Luminescent pH
Sensing. Inorg. Chem. 2017, 56 (4), 2159-2164.
(48) Elsaidi, S. K.; Ongari, D.; Mohamed, M. H.; Xu, W.;
Motkuri, R. K.; Haranczyk, M.; Thallapally, P. K., Metal Organic
Frameworks for Xenon Storage Applications. ACS Mater. Lett. 2020,
2 (3), 233-238.
(49) Angeli, G. K.; Sartsidou, C.; Vlachaki, S.; Spanopoulos, I.;
Tsangarakis, C.; Kourtellaris, A.; Klontzas, E.; Froudakis, G. E.;
Tasiopoulos, A.; Trikalitis, P. N., Reticular Chemistry and the
Discovery of a New Family of Rare Earth (4, 8)-Connected Metal-
ACS Paragon Plus Environment

Journal of the American Chemical Society
Page 10 of 10
1
2
3
4
5
Table of Contents artwork
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 Paragon Plus Environment