Strategic design of triphenylamine- and triphenyltriazine-based two-dimensional covalent organic frameworks for CO2 uptake and energy storage

Article abstract of DOI:10.1039/c8ta04781b

Hexagonally ordered covalent organic frameworks (COFs) are interesting new crystalline porous materials that have massive potential for application in gas storage. Herein, we report the synthesis of two series of two-dimensional hexagonally ordered COFs - TPA-COFs and TPT-COFs - through one-pot polycondensations of tris(4-aminophenyl)amine (TPA-3NH₂) and 2,4,6-tris(4-aminophenyl)triazine (TPT-3NH₂), respectively, with triarylaldehydes featuring different degrees of planarity, symmetry, and nitrogen content. All the synthesized COFs exhibited high crystallinity, large BET surface areas (up to 1747 m² g^-1), excellent thermal stability, and pore size distributions from 1.80 to 2.55 nm. The symmetry and planarity of the monomers strongly affected the degrees of crystallinity and the BET surface areas of the resultant COFs. In addition, these COFs displayed excellent CO₂ uptake efficiencies of up to 65.65 and 92.38 mg g^-1 at 298 and 273 K, respectively. The incorporation of the more planar and higher-nitrogen-content triaryltriazine unit into the backbones of the TPA-COFs and TPT-COFs enhanced the interactions with CO₂, leading to higher CO₂ uptakes. Moreover, the synthesized COFs exhibited electrochemical properties because of their conjugated structures containing redox-active triphenylamine groups. This study exposes the importance of considering the symmetry and planarity of the monomers when designing highly crystalline COFs; indeed, the structures of COFs can be tailored to vary their functionalities for specific applications.

Full text of DOI:10.1039/c8ta04781b

View Article Online
View Journal
Journal of
Materials Chemistry A
Accepted Manuscript
This article can be cited before page numbers have been issued, to do this please use: A. El-Mahdy, C.
Kuo, A. A. Alshehri, J. Kim, C. Young, Y. Yamauchi and S. Kuo, J. Mater. Chem. A, 2018, DOI:
10.1039/C8TA04781B.
This is an Accepted Manuscript, which has been through the
Volume
4 Number 1 7 January 2016 Pages 1–330
Royal Society of Chemistry peer review process and has been
accepted for publication.
Journal of
Materials Chemistry A
Accepted Manuscripts are published online shortly after
Materials for energy and sustainability
www.rsc.org/MaterialsA
acceptance, before technical editing, formatting and proof reading.
Using this free service, authors can make their results available
to the community, in citable form, before we publish the edited
article. We will replace this Accepted Manuscript with the edited
and formatted Advance Article as soon as it is available.
You can find more information about Accepted Manuscripts in the
author guidelines.
Please note that technical editing may introduce minor changes
to the text and/or graphics, which may alter content. The journal’s
standard Terms & Conditions and the ethical guidelines, outlined
in our author and reviewer resource centre, still apply. In no
event shall the Royal Society of Chemistry be held responsible
for any errors or omissions in this Accepted Manuscript or any
consequences arising from the use of any information it contains.
ISSN 2050-7488
PAPER
Kun Chang, Zhaorong Chang et al.
Bubble-template-assisted synthesis of hollow fullerene-like
MoS2 nanocages as a lithium ion battery anode material
rsc.li/materials-a

Page 1 of 10
Journal of Materials Chemistry A
CREATED USING THE RSC ARTICLE TEMPLATE (VER. 3.1) - SEE WWW.RSC.ORG/ELECTRONICFILES FOR DETAILS
View Article Online
DOI: 10.1039/C8TA04781B
www.rsc.org/xxxxxx | XXXXXXXX
ARTICLE TYPE
Strategic Design of Triphenylamine- and Triphenyltriazine-Based Two-
Dimensional Covalent Organic Frameworks for CO2 Uptake and Energy
Storage
5
Ahmed F. M. EL-Mahdy,a,b Cheng-Han Kuo,a Abdulmohsen Alshehri,c Christine Young,d Yusuke Yamauchi,e,f
Jeonghun Kim*e and Shiao-Wei Kuo*a
Received (in XXX, XXX) Xth XXXXXXXXX 200X, Accepted Xth XXXXXXXXX 200X
DOI: 10.1039/b000000x
Hexagonally ordered covalent organic frameworks (COFs) are interesting new crystalline porous materials that have massive potential
10 for application in gas storage. Herein, we report the synthesis of two series of twoꢀdimensional hexagonally ordered COFs—TPAꢀCOFs
and TPTꢀCOFs—through oneꢀpot polycondensations of tris(4ꢀaminophenyl)amine (TPAꢀ3NH2) and 2,4,6ꢀtris(4ꢀaminophenyl)triazine
(TPTꢀ3NH2), respectively, with triarylaldehydes featuring different degrees of planarity, symmetry, and nitrogen content. All the
synthesized COFs exhibited high crystallinity, large BET surface areas (up to 1747 m2 gꢀ1), excellent thermal stability, and pore size
distributions from 1.80 to 2.55 nm. The symmetry and planarity of the monomers strongly affected the degrees of crystallinity and the
15 BET surface areas of the resultant COFs. In addition, these COFs displayed excellent CO2 uptake efficiencies: up to of 65.65 and 92.38
mg gꢀ1 at 298 and 273 K, respectively. The incorporation of the more planar and higherꢀnitrogenꢀcontent triaryltriazine unit into the
backbones of the TPAꢀCOFs and TPTꢀCOFs enhanced the interactions with CO2, leading to higher CO2 uptakes. Moreover, the
synthesized COFs exhibited electrochemical properties because of their conjugated structures containing redoxꢀactive triphenylamine
groups. This study exposes the importance of considering the symmetry and planarity of the monomers when designing highly crystalline
20 COFs; indeed, the structures of COFs can be tailored to vary their functionalities for specific applications.
because of the high stability of imino bonds and the wide
availability of monomers containing aldehyde and amino
functional groups.35,36
Introduction
The past few years have witnessed the synthesis of various
collections of covalent organic frameworks (COFs).1–3 These
covalently bond frameworks are porous organic materials
that have light weight, high crystallinity, and high porosity;
most importantly, however, their chemical structures can be
designed and modified using organic synthesis to ensure
desired functions. Thus, they have garnered great attention
for their diverse applications in gas storage and separation,4–
7 chemical sensing,8–11 catalysis,12–16 membrane separation,17
environmental remediation,18 energy storage,19–22 drug
delivery,23ꢀ25 and electronic devices.26 The discovery of new
covalent bonds suitable for the construction of highly
crystalline organic frameworks remains a challenge. The
reported methods for the construction of COFs have
depended on the formation of strong covalent bonds through
a reversible condensation strategy using, for example,
boronic ester formation,27,28 Schiff base (imine)
condensation of aromatic amines and aromatic aldehydes,29–
One of the greatest attractions of COFs is that their
structures can be controlled by varying their organic
monomers.37,38 Nevertheless, controlling the crystallinity and
porosity of a COF remains challenging.39 Previous report
have suggested that the porosity and crystallinity of COFs
can be enhanced through the use of three methods. First, the
crystallinity of COFs has been improved by controlling the
layer interactions and layer planarity through the
introduction of hydrogen bonds.40 Second, strong πꢀstacking
between the intralayers of the COFs has generated highly
crystalline and porous COFs.41 Third, the crystallinity of
COFs has been controlled by adjusting the rigidity or
flexibility of the monomers. For example, Bein et al.42 and
Banerjee et al.43 discovered that flexible molecular docking
sites and monomer planarity played important roles in
determining the porosity and crystallinity of resulting COFs.
Previously, COFs having symmetrical monomer units in
their hexagonal structure have been constructed by other
researchers. Loh et al. described the utilization of
symmetrical monomers tetrakis(4ꢀformylphenyl)ethane and
tetrakis(4ꢀaminophenyl)ethane for the construction of 2Dꢀ
COF.44 In addition, Lotsch et al. reported the synthesis of
TTIꢀCOF through the imineꢀcondensation of two symmetric
31
triazine polymerization,32,33 and azodioxide formation.34
Among these approaches, imine condensation has been
particularly widely used for the synthesis of various COFs
having a range of crystallinities and porosities, mainly
monomers
tris(4ꢀformylphenyl)triazine
and
tris(4ꢀ
aminophenyl)triazine.45 Furthermore, Jiang et al. also
reported the utilization of symmetrical monomers tris(4ꢀ
aminophenyl)amine and tris(4ꢀformylphenyl)amine for the
synthesis of TFPAꢀTAPAꢀCOF, and tris(4ꢀformylphenyl)
benzene (TFPB), tris(4ꢀaminophenyl)benzene (TAPB) for
TFPBꢀTAPBꢀCOF.46
Although the examples above confirmed the crystallinity of
COFs, these structures had limited applications in gas storage or
electrochemical energy storage; furthermore, a few previous
reports have described the influence of both symmetry and
planarity of the monomers together on the properties and
applications
of
the
resultant
COFs.
Thus,
in
This journal is © The Royal Society of Chemistry [year]
Journal Name, [year], [vol], 00–00 |
1

CREATED USING THE RSC ARTICLEJToEuMrPnLAaTlEo(fVEMR.a3t.0e)r-iSaElsE CWhWeWm.RSisCt.OryRGA/ELECTRONICFILES FOR DETAILS
Page 2 of 10
View Article Online
DOI: 10.1039/C8TA04781B
www.rsc.org/xxxxxx | XXXXXXXX
ARTICLE TYPE
Scheme 1. (A) Schematic strategies for the synthesis of three isoreticular 2D TPAꢀCOFs from triphenylamine with three aldehyde
monomers of various planarities. (B) 2D Simulation of TPAꢀCOFs. Color code: C, gray; N, blue.
Scheme 2. (A) Schematic strategies for the synthesis of three isoreticular 2D TPTꢀCOFs from triphenyl triazine with three aldehyde
monomers of different planarity, and (B) 2Dꢀsimulation of TPTꢀCOFs. C: gray, N: blue.
2
| Journal Name, [year], [vol], 00–00
This journal is © The Royal Society of Chemistry [year]

Page 3 of 10
Journal of Materials Chemistry A
CREATED USING THE RSC ARTICLE TEMPLATE (VER. 3.1) - SEE WWW.RSC.ORG/ELECTRONICFILES FOR DETAILS
View Article Online
DOI: 10.1039/C8TA04781B
www.rsc.org/xxxxxx | XXXXXXXX
ARTICLE TYPE
this present study, we investigated the ability to control the
crystallinity of COFs as well as its effect on the uptake of
carbon dioxide (CO2). We designed two series of isoreticular
twoꢀdimensional (2D) COFs—TPAꢀCOFs and TPTꢀCOFs,
having the same hexagonal topology—through oneꢀpot
polycyclocondensations of tris(4ꢀaminophenyl)amine (TPAꢀ
3NH2) and 2,4,6ꢀtris(4ꢀaminophenyl)triazine (TPTꢀ3NH2),
respectively, as triarylamine monomers, and three
triarylaldehyde monomers having different degrees of
planarity: tris(4ꢀformylphenyl)amine (TPAꢀ3CHO), 2,4,6ꢀ
tris(4ꢀformylphenyl)pyridine (TPPꢀ3CHO), and 2,4,6ꢀtris(4ꢀ
formylphenyl)triazine (TPTꢀ3CHO), as displayed in
Schemes 1 and 2.
state 13CꢀNMR spectroscopy was further utilized to confirm
the formation of TPAꢀCOFs and TPTꢀCOFs. As shown in
Figures S4, S6, S8, S12, and S16, the 13C NMR spectra of
the triarylamine monomers were exhibited a signal at 154ꢀ
143 ppm for the carbon atom attached to amino (CꢀNH2)
group, while the triarylaldehyde monomers were exhibited a
strong signal at 193ꢀ191 ppm for the aldehyde carbonyl C=O
group. In addition, the 13C NMR spectra of the TPTꢀ3NH2
and TPTꢀ3CHO monomers showed a massive peak at 170
and 171 ppm for the triazine core, respectively. After
polycondensations, the solid state 13C NMR spectra of TPAꢀ
COFs and TPTꢀCOFs were characterized by the
disappearance of the aldehyde carbonyl C=O group and the
appearance of single main peaks at around 161 ppm for the
TPAꢀCOFs and at around 164 ppm for the TPTꢀCOFs,
attributable to the resonances of the imino C=N carbon
nuclei in the six COFs.44,47 In addition, the 13C NMR spectra
of the triazineꢀcontaining COFs were featured a downfield
shift of the triazine core to be around 176 ppm (Figure 1).
Furthermore, thermogravimetric analysis (TGA) of the TPAꢀ
COFs and TPTꢀCOFs revealed that these six COFs are
thermally stable up to 510–574 °C (Figure S28, Table S2).
Results and Discussion
To investigate the effects of the planarity and symmetry of
the monomers on the porosity and crystallinity of the COFs
and their applications in CO2 capture, we synthesized TPAꢀ
COFs and TPTꢀCOFs through the reactions of TPAꢀ3NH2
(
Figures S1-S4 and S17) and TPTꢀ3NH2 (Figures S5-S6,
and S18), respectively, as flexible triarylamine monomers,
with TPAꢀ3CHO (Figures S7-S8 and S19), TPPꢀ3CHO
(
Figures S9-S12 and S20) and TPTꢀ3CHO (Figures S13-16
Using the temperature of 10% weight loss (Td10) and the
and S21) as flexible triarylaldehyde monomers. As listed in
Table 1, TPTꢀ3NH2 is more planar than TPAꢀ3NH2, and
TPTꢀ3CHO is more planar than TPPꢀ3CHO and TPAꢀ
3CHO. The TPAꢀCOF series of compounds were produced
onset temperature (Tonset) as standards, we found that the
TPTꢀTPTꢀCOF (TPTꢀCOFꢀ6) was the most thermally stable
of our COFs, with a value of Td10 of 574 °C, a value of Tonset
of 554 ºC and a char yield of 61%, while TPAꢀTPAꢀCOF
(TPAꢀCOFꢀ1) was the most thermally unstable COF with a
under
solvothermal
conditions
through
oneꢀpot
polycondensations between TPAꢀ3NH2 and TPAꢀ3CHO,
TPPꢀ3CHO, and TPTꢀ3CHO, in mesitylene/dioxane (1:1)
containing acetic acid as a catalyst, at 120 °C for 4 days to
yield TPAꢀTPAꢀCOF (TPAꢀCOFꢀ1, 87% yield), TPAꢀTPPꢀ
COF (TPAꢀCOFꢀ2, 85%), and TPAꢀTPTꢀCOF (TPAꢀCOFꢀ3,
88%), respectively (Scheme 1). Similarly, the TPTꢀCOF
series of compounds were also obtained through oneꢀpot
polycondensations between TPTꢀ3NH2 and TPAꢀ3CHO,
TPPꢀ3CHO, and TPTꢀ3CHO to give TPTꢀTPAꢀCOF (TPTꢀ
COFꢀ4, 82%), TPTꢀTPPꢀCOF (TPTꢀCOFꢀ5, 86%), and TPTꢀ
TPTꢀCOF (TPTꢀCOFꢀ6, 89%), respectively (Scheme 2). The
synthesized TPAꢀCOFs and TPTꢀCOFs were insoluble in
value of Td10 of 510 °C, a value of Tonset of 475 ºC and a char
yield of 58%; for TPAꢀTPPꢀCOF (TPAꢀCOFꢀ2), TPAꢀTPTꢀ
COF (TPAꢀCOFꢀ3), TPTꢀTPAꢀCOF (TPTꢀCOFꢀ4), and
TPTꢀTPPꢀCOF (TPTꢀCOFꢀ5), the values of Td10 were 520,
531, 549, and 553 °C, respectively, and the char yields were
67, 58, 55, and 49%, respectively. Moreover, TPAꢀTPPꢀ
COF (TPAꢀCOFꢀ2), TPAꢀTPTꢀCOF (TPAꢀCOFꢀ3), TPTꢀ
TPAꢀCOF (TPTꢀCOFꢀ4), and TPTꢀTPPꢀCOF (TPTꢀCOFꢀ5)
showed values of Tonset of 485, 503, 539, and 541 ºC,
respectively. Thus, the symmetry and planarity of the
monomers highly affect the thermal stability. For the
symmetrical monomers, the presence of the symmetrical and
most planar TPTꢀ3NH2 and TPTꢀ3CHO monomers together
in the same COF (TPTꢀCOFꢀ6) largely enhanced the thermal
stability, while the presence of the symmetrical and least
planar TPAꢀ3NH2 and TPAꢀ3CHO monomers together in
the same COF (TPAꢀCOFꢀ1) largely decreased the thermal
stability. On the other hand, for the unsymmetrical
monomers, incorporation of the planar monomer appeared to
increase the thermal stability of the resultant COFs; TPAꢀ
TPTꢀCOF (TPAꢀCOFꢀ3) is more thermally stable than TPAꢀ
TPPꢀCOF (TPAꢀCOFꢀ2), and TPTꢀTPPꢀCOF (TPTꢀCOFꢀ5)
is more thermally stable than TPTꢀTPAꢀCOF (TPTꢀCOFꢀ4).
We studied the crystal structures of the TPAꢀCOFs and
TPTꢀCOFs using powder Xꢀray diffraction (PXRD) in
combination with computational simulations. As displayed
in Figure 2A, the PXRD patterns of the TPAꢀCOFs
confirmed the formation of crystalline frameworks having
periodic hexagonal 2D honeycombꢀtype lattices. The
common organic solvents, including acetone,
N,Nꢀ
dimethylformamide, dimethylsulfoxide, tetrahydrofuran, and
dioxane.
The success of the polycondensations yielding the COFs
was confirmed using Fourier transform infrared (FTIR)
spectroscopy, elemental analysis, and solid state 13C CP
MAS NMR spectra. The FTIR spectra of the triarylamine
monomers were characterized by signals at 3460ꢀ3207 cmꢀ1
for the NH2 groups and 1579ꢀ1504 cmꢀ1 for the aromatic
C=C groups, while the triarylaldehyde monomers were
characterized by signals at 1706ꢀ1693 cmꢀ1 for the C=O
groups and 1598ꢀ1504 cmꢀ1 for the aromatic C=C groups
(
Figures S22-S27). For more convenient, we focused on the
functionalized NH2 and C=O groups. After polyꢀ
condensations, the FTIR spectra of the TPAꢀCOFs and TPTꢀ
COFs revealed the almost complete disappearance of the
signals for the NH2 and C=O units of the monomers, and the
appearance of strong signals at 1627ꢀ1616 cm-1 representing
the C=N stretching vibrations,44ꢀ46 suggesting the formation
of the COFs through Schiffꢀbase polycondensations. The
terminal NH2 and C=O groups on the surface of the resultant
COFs were appeared as weak signals at 3475ꢀ3380 and
1703ꢀ1697 cmꢀ1, respectively. Elemental analyses of the
TPAꢀCOFs and TPTꢀCOFs were compatible with the
theoretical values for their 2D sheets (Table S1). The solid
structure
of
TPAꢀTPAꢀCOF
(TPAꢀCOFꢀ1)
was
of
characterized by a sharp diffraction peak at a value of 2
θ
5.05°, corresponding to a (100) reflection, in addition to two
other peaks at 9.15 and 13.66°, which we assign to (210) and
(310) reflections, respectively. We attribute the slightly
broad peak at a value of 2θ of 20.25° to the (100) reflection
caused by πꢀstacking between the COF layers. TPAꢀTPPꢀ
COF (TPAꢀCOFꢀ2) also exhibited PXRD peaks at values of
This journal is © The Royal Society of Chemistry [year]
Journal Name, [year], [vol], 00–00 | 3

CREATED USING THE RSC ARTICLEJToEuMrPnLAaTlEo(fVEMR.a3t.0e)r-iaSElsE CWhWeWm.RSisCt.OryRGA/ELECTRONICFILES FOR DETAILS
Page 4 of 10
View Article Online
DOI: 10.1039/C8TA04781B
www.rsc.org/xxxxxx | XXXXXXXX
ARTICLE TYPE
Table 1. DFT geometry optimization of the monomers, using the B3LYP/6ꢀ311G(d,p) method.
2
θ
of 4.63, 8.11, 12.19, and 21.10°, attributed to the (100),
(100), (210), (200), (310), and (001) reflections,
respectively. TPTꢀTPPꢀCOF (TPTꢀCOFꢀ5) provided PXRD
peaks at values of 2θ of 4.05, 6.29, 8.18, 10.60, and 25.48°,
(210), (310), and (001) reflections, respectively.
Furthermore, the TPAꢀTPTꢀCOF (TPAꢀCOFꢀ3) exhibited its
main PXRD peak at a value of 2
θ
of 4.62°, corresponding to
attributable to the (100), (210), (200), (310), and (001)
reflections, respectively. Finally, TPTꢀTPTꢀCOF (TPTꢀ
COFꢀ6) displayed its main PXRD peak at a value of 2θ of
4.04°,corresponding to the (100) reflection, as well as four
other peaks at 6.97, 8.23, 10.67, and 25.56°, which we assign
to the (210), (200), (310) and (001) reflections, respectively.
TPTꢀCOFꢀ4, TPTꢀCOFꢀ5, and TPTꢀCOFꢀ6 featured values
the (100) reflection, as well as four other peaks at 5.83, 8.07,
12.35, and 21.25°, that we assign to the (210), (200), (310),
and (001) reflections, respectively. In addition, we calculated
the average
interlayer distances between the 2D sheets of planes,
according to the Bragg equation: nλ = 2 sin , where is an
integer (here, = 1) and λ is the wavelength of the incident
dꢀspacings between the 100 planes (d100) and the
d
θ
n
n
of d100 of 1.91, 2.18, and 2.19 nm, and interlayer distances of
waves (here, λ = 0.154 nm). For TPAꢀTPAꢀCOF (TPAꢀ
COFꢀ1), TPAꢀTPPꢀCOF (TPAꢀCOFꢀ2), and TPAꢀTPTꢀCOF
(TPAꢀCOFꢀ3), the values of d100 were 1.75, 1.90, and 1.91
nm, respectively, and their interꢀlayer distances were 4.40,
4.21, and 4.20 Å, respectively (Table 2). The TPTꢀCOFs
also possessed periodic hexagonal 2D honeycombꢀtype
frameworks (Figure 2C). TPTꢀTPAꢀCOF (TPTꢀCOFꢀ4)
3.50, 3.49, and 3.48 Å, respectively (Table 2).
The experimental PXRD reflections of the TPAꢀCOFs and
TPTꢀCOFs matched well with their theoretical patterns
(
Figures 2A and 2C, purple curves), as evidenced by
negligible differences (Figure 2A and 2C, black curves)
obtained from the structural simulations of the AAꢀeclipsed
layer stacking modes
(Tables S3-S8, Figure S29).
exhibited PXRD diffraction peaks at values of 2
5.58, 7.75, 10.35, and 25.45°, which we assigned to the
θ
of 4.62,
Interestingly, these results suggested that the level of
planarity in the precursor monomer strongly affected the
4
| Journal Name, [year], [vol], 00–00
This journal is © The Royal Society of Chemistry [year]

Page 5 of 10
Journal of Materials Chemistry A
CREATED USING THE RSC ARTICLE TEMPLATE (VER. 3.1) - SEE WWW.RSC.ORG/ELECTRONICFILES FOR DETAILS
View Article Online
DOI: 10.1039/C8TA04781B
www.rsc.org/xxxxxx | XXXXXXXX
ARTICLE TYPE
(A)
(A)
(a) TPA-COF-1
(b) TPA-COF-2
(c) TPA-COF-3
f,g
b,c,d,e
g
d
c
a
f
e
b
a
a
TPAꢀCOFꢀ1
i,j,k
j
b,c,d,e,f,g,h
c,d,e,f
e
a
i
d
h
b
f
TPAꢀCOFꢀ2 kg
c
g,h
5
10 15 20 25 30
5
10 15 20 25 30
5
10 15 20 25 30
h
2θ
/
(
degree
)
2θ
/
(
degree
)
2θ / (degree)
d
g
b
c
f
e
(B)
(C)
a
a
b
TPAꢀCOFꢀ3
(B)
190
180
170
160
150
140
130
120
110
100
Chemical shift (ppm)
g,h
h
c
a
f
(d) TPT-COF-4
(e) TPT-COF-5
(f) TPT-COF-6
g
b
e
c,d,e,f
b
d
TPTꢀCOFꢀ4
a
j,k
k
a
j
b
d
i
h
c,d,e,f,g,h,i
b
f
c
a
TPTꢀCOFꢀ5
e
g
h,i
i
d
a
f
h
c
f,g
g
5
10 15 20 25 30
5
10 15 20 25 30
5
10 15 20 25 30
TPTꢀCOFꢀ6 eb
a,b
d,e
c
2θ
/
(
degree)
2θ
/
(
degree)
2θ / (degree)
(D)
190
180
170
160
150
140
130
120
110
100
Chemical shift (ppm)
Figure 1. Solid state 13C CP MAS NMR spectra of (A) TPAꢀ
COFs: TPAꢀTPAꢀCOF (TPAꢀCOFꢀ1), TPAꢀTPPꢀCOF (TPAꢀ
COFꢀ2), and TPAꢀTPTꢀCOF (TPAꢀCOFꢀ3); and (B) TPTꢀCOFs:
TPTꢀTPAꢀCOF (TPTꢀCOFꢀ4), TPTꢀTPPꢀCOF (TPTꢀCOFꢀ5), and
TPTꢀTPTꢀCOF (TPTꢀCOFꢀ6).
Figure 2. (A, C) PXRD patterns of the (A) TPAꢀCOFs and (C)
TPTꢀCOFs (green for the experimentally observed) compared
with the simulated patterns calculated for the Rietveld refinement
(purple), their difference (black), AAꢀstacking (blue), and ABꢀ
stacking (red). (B, D) Views of spaceꢀfilling models of the (B)
TPAꢀCOFs and (D) TPTꢀCOFs along the AAꢀstacking crystal
structures (color code: C, gray; N, blue).
crystallinity of the resulting COF. By increasing the
planarity of the monomers, the value of d100 increased and
the interlayer distance decreased. It has previously reported
that the crystallinity of the COF can be improved by
increasing the planarity of the linkage monomers, which is
compatible with our results.47 The most planar monomers,
TPTꢀ3NH2 and TPTꢀ3CHO, produced TPTꢀCOFꢀ6, which
symmetrical and most planar TPTꢀ3NH2 and TPTꢀ3CHO
monomers, was 1535 m2 g-1, significantly higher than that
(714 m2 g-1) of TPAꢀTPAꢀCOF (TPAꢀCOFꢀ1), obtained
from the symmetrical and least planar TPAꢀ3NH2 and TPAꢀ
3CHO monomers. On the other hand, when using
possessed the largest value of d100 (2.19 nm) and the shortest
interlayer distance (3.48 Å); in contrast, the least planar
monomers—TPAꢀ3NH2 and TPAꢀ3CHO—produced TPAꢀ
COFꢀ1, which featured the lowest value of d100 (1.75 nm)
and the longest interlayer distance (4.40 Å). The permanent
porosity of the TPAꢀCOFs and TPTꢀCOFs was demonstrated
by measuring their N2 sorption at 77 K. As presented in
Figure 3, the sorption curves of all of the COFs displayed
the type I isothermal behavior that is characteristic of
microporous polymers. Interestingly, the Brunauer–Emmett–
Teller (BET) and Langmuir surface areas of the symmetrical
and unsymmetrical COFs were strongly affected by the
planarity of the monomers. Thus, while the PXRD data
revealed an increasing degree of crystallinity upon
increasing the planarity of the monomers, we observed a
further demarcation in the BET and Langmuir surface areas
of the COFs. In the case of the symmetrical monomers, the
BET surface area of TPTꢀTPTꢀCOF (TPTꢀCOFꢀ6), produced
from the
Table 2. PXRD and BET parameters of the synthesized COFs.
d100
Pore size
(nm)
SBET
(m2/g)
SLangmuir
(m2/g)
Pore vol.
(cm2/g)
(nm)
TPAꢀCOFꢀ1 1.75
TPAꢀCOFꢀ2 1.90
TPAꢀCOFꢀ3 1.91
TPTꢀCOFꢀ4 1.91
TPTꢀCOFꢀ5 2.18
TPTꢀCOFꢀ6 2.19
1.93
1.80
2.01
2.13
2.50
2.55
714
478
1058
704
0.517
0.333
0.353
0.767
1.102
1.019
557
823
1132
1747
1535
1657
2617
2456
This journal is © The Royal Society of Chemistry [year]
Journal Name, [year], [vol], 00–00 | 5

CREATED USING THE RSC ARTICLEJToEuMrPnLAaTlEo(fVEMR.a3t.0e)r-iSaElsE CWhWeWm.RSisCt.OryRGA/ELECTRONICFILES FOR DETAILS
Page 6 of 10
View Article Online
DOI: 10.1039/C8TA04781B
www.rsc.org/xxxxxx | XXXXXXXX
ARTICLE TYPE
100
100
80
60
40
20
0
360
240
200
160
120
80
240
200
160
120
80
(B) at 273K
(A) at 298 K
(B) TPA-COF-2
(A) TPA-COF-1
(C) TPA-COF-3
320
80
TPA-COF-1
TPA-COF-1
280
240
200
160
120
80
TPA-COF-2
TPA-COF-2
TPA-COF-3
60
TPA-COF-3
40
20
0
40
40
40
0
0
0
0.0 0.2 0.4 0.6 0.8 1.0
0.0 0.2 0.4 0.6 0.8 1.0
0.0 0.2 0.4 0.6 0.8 1.0
Relative Pressure (P/Po)
Relative Pressure (P/Po)
Relative Pressure (P/Po)
0.0
0.2
0.4
0.6
0.8
1.0
0.0
0.2
0.4
0.6
0.8
1.0
Relative Pressure (P/P0)
Relative Pressure (P/P0)
540
800
600
400
200
0
800
600
400
200
0
(F) TPT-COF-6
100
80
60
40
20
0
(D) TPT-COF-4
(E) TPT-COF-5
100
480
(C) at 298 K
(D) at 273K
420
360
300
240
180
120
60
TPT-COF-4
TPT-COF-5
TPT-COF-6
80
60
40
20
0
TPTCOF-4
(A)
TPT-COF-5
TPT-COF-6
0
0.0 0.2 0.4 0.6 0.8 1.0
0.0 0.2 0.4 0.6 0.8 1.0
0.0 0.2 0.4 0.6 0.8 1.0
Relative Pressure (P/Po)
Relative Pressure (P/Po)
Relative Pressure (P/Po)
0.0
0.2
0.4
0.6
0.8
1.0
0.0
0.2
1.0
Relati0v.e4 Pressu0r.e6(P/P0)0.8
Figure 3. N2 adsorption (●, filled cycles) and desorption (○,
open cycles) isotherms, measured at 298 K, of the TPAꢀ
COFs: (A) TPAꢀTPAꢀCOF (TPAꢀCOFꢀ1), (B) TPAꢀTPPꢀ
COF (TPAꢀCOFꢀ2), and (C) TPAꢀTPTꢀCOF (TPAꢀCOFꢀ3),
and the TPTꢀCOFs: (D) TPTꢀTPAꢀCOF (TPTꢀCOFꢀ4), (E)
TPTꢀTPPꢀCOF (TPTꢀCOFꢀ5), and (F) TPTꢀTPTꢀCOF (TPTꢀ
COFꢀ6).
Relative Pressure (P/P0)
Figure 5. CO2 uptake profiles of (A, B) the TPAꢀCOFs:
TPAꢀTPAꢀCOF (TPAꢀCOFꢀ1), TPAꢀTPPꢀCOF (TPAꢀCOFꢀ
2), and TPAꢀTPTꢀCOF (TPAꢀCOFꢀ3); and (C, D) the TPTꢀ
COFs: TPTꢀTPAꢀCOF (TPTꢀCOFꢀ4), TPTꢀTPPꢀCOF (TPTꢀ
COFꢀ5), and TPTꢀTPTꢀCOF (TPTꢀCOFꢀ6), measured at (A,
C) 298 K and (B, D) 273 K.
0.6
0.4
0.2
0.0
0.25
0.20
0.15
0.10
0.05
0.00
0.8
0.6
0.4
0.2
0.0
(A) TPA-COF-1
(B) TPA-COF-2
(C) TPA-COF-3
These data indicate that two main factors affected the BET
and Langmuir surface areas of the COFs: symmetry and
planarity. For the symmetrical COFs, lowering the planarity
of the monomers induced a lower surface area; similarly for
the unsymmetrical COFs, Lowering the planarity of the
monomers led to a lower surface area.
0
2
4
6
8
10
0
2
4
6
8
10
0
2
4
6
8
10
Pore Width (nm)
Pore Width (nm)
Pore Width (nm)
We used the nonlocal density functional theory method to
calculate the pore size distributions of the COFs. The TPAꢀ
COFs—TPAꢀTPAꢀCOF (TPAꢀCOFꢀ1), TPAꢀTPPꢀCOF
(TPAꢀCOFꢀ2), and TPAꢀTPTꢀCOF (TPAꢀCOFꢀ3)—were
microporous materials having pore sizes of 1.93, 1.80, and
2.01 nm, respectively. On the other hand, the TPTꢀCOFs—
TPTꢀTPAꢀCOF (TPTꢀCOFꢀ4), TPTꢀTPPꢀCOF (TPTꢀCOFꢀ
5), and TPTꢀTPTꢀCOF (TPTꢀCOFꢀ6)—were a sort of
mesoporous materials having pore sizes of 2.13, 2.50, and
0.20
0.15
0.10
0.05
0.00
0.3
0.2
0.1
0.0
0.21
0.14
0.07
0.00
(F) TPT-COF-6
(D) TPT-COF-4
(E) TPT-COF-5
0
2
4
6
8
10
0
2
4
6
8
10
0
2
4
6
8
10
Pore Width (nm)
Pore Width (nm)
Pore Width (nm)
Figure 4. Pore size distribution profiles of the TPAꢀCOFs:
(A) TPAꢀTPAꢀCOF (TPAꢀCOFꢀ1), (B) TPAꢀTPPꢀCOF
(TPAꢀCOFꢀ2), and (C) TPAꢀTPTꢀCOF (TPAꢀCOFꢀ3); and
the TPTꢀCOFs: (D) TPTꢀTPAꢀCOF (TPTꢀCOFꢀ4), (E) TPTꢀ
TPPꢀCOF (TPTꢀCOFꢀ5), and (F) TPTꢀTPTꢀCOF (TPTꢀ
COFꢀ6).
2.55 nm, respectively (Figure 4, Table 2).
We observed the surface morphologies of the six COFs
through scanning electron microscopy (SEM, Figure S30).
The SEM images of TPAꢀTPAꢀCOF (TPAꢀCOFꢀ1) and
TPAꢀTPPꢀCOF (TPAꢀCOFꢀ2) revealed homogeneous
assemblies of loose agglomerates of very small particles
having irregular shapes (Figures S30A and S30B), while
those of TPTꢀTPAꢀCOF (TPTꢀCOFꢀ4) and TPTꢀTPPꢀCOF
(TPTꢀCOFꢀ5) revealed chipꢀlike morphologies of
unsymmetrical monomers (Table 2), TPAꢀTPPꢀCOF (TPAꢀ
COFꢀ2), prepared from the least planar TPPꢀ3CHO
monomer, exhibited a lower BET surface area (478 m2 g-1)
than that (557 m2 gꢀ1) of TPAꢀTPTꢀCOF (TPAꢀCOFꢀ3),
prepared from the most planar TPTꢀ3CHO monomer (Table
2). Likewise, TPTꢀTPAꢀCOF (TPTꢀCOFꢀ4) featured a BET
surface area (1132 m2 g-1) lower than that (1747 m2 gꢀ1) of
TPTꢀTPPꢀCOF (TPTꢀCOFꢀ5). In addition, the Langmuir
surface area of these COFs showed the same findings; TPTꢀ
TPTꢀCOF (TPTꢀCOFꢀ6) exhibited a Langmuir surface area
(2456 m2 gꢀ1) higher than that (1058 m2 gꢀ1) of TPAꢀTPAꢀ
COF (TPAꢀCOFꢀ1), TPAꢀTPPꢀCOF (TPAꢀCOFꢀ2) showed
a lower Langmuir surface area (704 m2 gꢀ1) than that (823 m2
gꢀ1) of TPAꢀTPTꢀCOF (TPAꢀCOFꢀ3), and TPTꢀTPAꢀCOF
(TPTꢀCOFꢀ4) exhibited a Langmuir surface area (1657 m2 gꢀ
1) lower than that (2617 m2 gꢀ1) of TPTꢀTPPꢀCOF (TPTꢀ
COFꢀ5).
micrometer dimensions
(Figures S30D and S30E).
Interestingly, TPAꢀTPTꢀCOF (TPAꢀCOFꢀ3) and TPTꢀTPTꢀ
COF (TPTꢀCOFꢀ6) exhibited rodꢀlike morphologies as well
as agglomerates of tiny particles (Figures S30C and S30F).
We examined the degrees of CO2 adsorption of each
series particularly; TPAꢀCOFs and TPTꢀCOFs at
temperatures of 298 and 273 K (Figure 5). The nitrogen
content and nitrogen nucleophilicity are strongly affected the
CO2 uptake efficiency of the prepared COFs. For the TPAꢀ
COFs series, TPAꢀTPTꢀCOF (TPAꢀCOFꢀ3), which we had
prepared from the highestꢀnitrogenꢀcontent TPTꢀ3CHO
monomer, exhibited the highest CO2 uptake capacities:
63.94 and 91.15 mg g-1 at 298 and 273 K, respectively.
6
| Journal Name, [year], [vol], 00–00
This journal is © The Royal Society of Chemistry [year]

Page 7 of 10
Journal of Materials Chemistry A
CREATED USING THE RSC ARTICLE TEMPLATE (VER. 3.1) - SEE WWW.RSC.ORG/ELECTRONICFILES FOR DETAILS
View Article Online
DOI: 10.1039/C8TA04781B
www.rsc.org/xxxxxx | XXXXXXXX
ARTICLE TYPE
Figure 6. Cyclic voltammograms of the COFs measured at 5
mV s-1: (A) TPAꢀCOFꢀ1, (B) TPAꢀCOFꢀ2, (C) TPAꢀCOFꢀ3,
(D) TPTꢀCOFꢀ4, (E) TPTꢀCOFꢀ5, and (F) TPTꢀCOFꢀ6.
Figure 7. Galvanostatic charge/discharge curves of the
COFs measured at various current densities: (A) TPAꢀCOFꢀ
1, (B) TPAꢀCOFꢀ2, (C) TPAꢀCOFꢀ3, (D) TPTꢀCOFꢀ4, (E)
TPTꢀCOFꢀ5, and (F) TPTꢀCOFꢀ6.
TPAꢀTPPꢀCOF (TPAꢀCOFꢀ2), featuring three triarylamine
and three triarylpyridine units in each hexagonal pore,
displayed CO2 uptake capacities of 45.88 and 82.42 mg g-1 at
298 and 273 K, respectively. These capacities are 1.2ꢀfold
higher than those of TPAꢀTPAꢀCOF (TPAꢀCOFꢀ1) with six
triarylamine units in the hexagonal pore. The nitrogen
content in TPAꢀTPAꢀCOF (TPAꢀCOFꢀ1) and TPAꢀTPPꢀ
COF (TPAꢀCOFꢀ2) is similar. Therefore, the enhanced CO2
uptake efficiency of TPAꢀTPPꢀCOF (TPAꢀCOFꢀ2) over
TPAꢀTPAꢀCOF (TPAꢀCOFꢀ1) was presumably due to the
steric hindrance around the nitrogen atom in the nonꢀplanar
triarylamine unit being more than that in the planar
triarylpyridine unit. As steric hindrance around nitrogen
atom increased, the nucleophilicity of the nitrogen atom
decreased and thus the number of adsorbed carbon dioxide
molecules also decreased.48 Similarly, for the TPTꢀCOF
series,
TPTꢀTPTꢀCOF
(TPTꢀCOFꢀ6),
having
six
triaryltriazine units in its hexagonal pore, provided the
highest CO2 uptake capacities: 65.65 and 92.38 mg g-1 at 298
and 273 K, respectively. TPTꢀTPPꢀCOF (TPTꢀCOFꢀ5)
exhibited CO2 uptake capacities of 41.00 and 59.44 mg g-1 at
298 and 273 K, respectively. These capacities are 1.1ꢀfold
higher than those of TPTꢀTPAꢀCOF (TPTꢀCOFꢀ4). Thus,
increases in the nitrogen content and nitrogen nucleophilicity
of the monomer led to an increase in the CO2 uptake
capacity of the COF. We observed the same phenomena for
both the TPAꢀCOF and TPTꢀCOF series.
Figure 8. Specific capacitances of the COFs determined
from galvanostatic charge/discharge data at various current
densities: (A) TPAꢀTPAꢀCOFꢀ1, (B) TPAꢀCOFꢀ2, (C) TPAꢀ
COFꢀ3, (D) TPTꢀCOFꢀ4, (E) TPTꢀCOFꢀ5, and (F) TPTꢀ
COFꢀ6.
TPTꢀTPPꢀCOF (TPTꢀCOFꢀ5), and TPTꢀTPTꢀCOF (TPTꢀ
COFꢀ6), these values were 9.70, 16.97, and 30.59 kJ mol-1,
respectively. The trends in these values of
Qst reveal that the
incorporation of higherꢀnitrogenꢀcontent triaryltriazine units
into the backbones of the TPAꢀCOFs and TPTꢀCOFs
encouraged stronger interactions with CO2. On the other
To support these observations, we calculated the isosteric
heat of adsorption (Qst) from the CO2 adsorption data
measured at 298 and 273 K, according to Clausius–
Clapeyron equation. Figures S31-S36 showed the fitting
isotherms of each COF which indicated that at a low loading
of CO2 (0.1 mmol/g, as standard), TPAꢀTPAꢀCOF (TPAꢀ
COFꢀ1), TPAꢀTPPꢀCOF (TPAꢀCOFꢀ2), and TPAꢀTPTꢀCOF
(TPAꢀCOFꢀ3) provided values of Qst of 15.92, 25.88, and
28.11 kJ mol-1, respectively; for TPTꢀTPAꢀCOF (TPTꢀCOFꢀ
4),
hand, the value of
Qst for TPAꢀTPAꢀCOF (TPAꢀCOFꢀ1) was
lower than that of TPAꢀTPPꢀCOF (TPAꢀCOFꢀ2), and for
TPTꢀTPAꢀCOF (TPTꢀCOFꢀ4) it was lower than that of TPTꢀ
TPPꢀCOF (TPTꢀCOFꢀ5), confirming that the incorporation
of the more nucleophilic triarylpyridine units into the
backbones of COFs enhanced the quadrupolar interactions
with CO2.
This journal is © The Royal Society of Chemistry [year]
Journal Name, [year], [vol], 00–00 | 7

CREATED USING THE RSC ARTICLEJToEuMrPnLAaTlEo(fVEMR.a3t.0e)r-iSaElsE CWWheWm.RSisCt.OryRGA/ELECTRONICFILES FOR DETAILS
Page 8 of 10
View Article Online
DOI: 10.1039/C8TA04781B
www.rsc.org/xxxxxx | XXXXXXXX
ARTICLE TYPE
Next, we examined the redox activity of the COFs
containing triphenylamine groups in the backbones
(highlighted in red in their chemical structures, Figure 6).
Generally, triphenylamine groups are redoxꢀactive units that
can store electrochemical energy.49,50 Among our six
samples, the COFsꢀ1ꢀ4 featured triphenylamine groups.
Cyclic voltammetry (CV) revealed the redox behavior of the
COFsꢀ1ꢀ4, with reversible redox processes occurring in a
potential window of 0.2ꢀ0.7 V (Figures 6A-D and S37A-D).
In contrast, no redox peaks appeared in the CV traces of
greater content of micropores decreased the specific
capacitance when the COFs had the same number of redoxꢀ
active groups. This study not only emphasizes the
importance of monomer symmetry and planarity on the
crystallinity of the resultant COFs but also exposes the
impact of these features on CO2 uptake and, hence,
environmental applications. In addition, it appears that COFs
containing redoxꢀactive groups might be suitable for
application in energy storage systems.
TPTꢀCOFꢀ5 and TPTꢀCOFꢀ6 (Figures 6E-F and S37E-F
)
Acknowledgements
because their unsaturated N=C units were unreactive in
presence of H+ (from the H2SO4 electrolyte), in contrast to
the higher basicity of C–NH–C units.51 To test their
suitability for use as pseudocapacitors, we calculated the
specific capacitances of all of our samples from the
galvanostatic charge/discharge (GCD) data (Figure 7).
Figure 8 presents the specific capacitances of these COFs.
Although TPTꢀCOFꢀ5 and TPTꢀCOFꢀ6 had high surface
areas, they displayed very small specific capacitances, due to
the absence of redoxꢀactive groups. Notably, the specific
capacitances were enhanced upon increasing the number of
triphenylamine groups. For example, TPAꢀTPAꢀCOFꢀ1 has
six triphenylamine groups, while the COFsꢀ2ꢀ4 have three;
TPAꢀTPAꢀCOFꢀ1 exhibited the highest specific capacitance
of 51.3 F gꢀ1 at 0.2 A gꢀ1 which is a value higher than that of
28 F gꢀ1 at 0.2 A gꢀ1 for a previously reported βꢀ
ketoenamineꢀbased 2D COF.52 Although the COFsꢀ2ꢀ4 all
featured three triphenylamine groups, their specific
capacitances were 14.4, 5.1, and 2.4 F gꢀ1, respectively, at
0.2 A gꢀ1. From these results, we conclude that the redoxꢀ
active groups are an important factor affecting the
capacitance, but porosity control is also critical when
designing COFs for use as supercapacitors.
This study was supported financially by the Ministry of Science
and Technology, Taiwan, under contracts MOST 106ꢀ2221ꢀEꢀ
110ꢀ067ꢀMY3 and 105ꢀ2221ꢀEꢀ110ꢀ092ꢀMY3.
Notes and references
1
2
3
4
S. Y. Ding and W. Wang, Chem. Soc. Rev., 2013, 42, 548ꢀ
568.
X. Feng, X. Ding and D. Jiang, Chem. Soc. Rev., 2012, 41
,
6010ꢀ6022.
H. L. Qian, C. X. Yang and X. P. Yan, Nat. Commun.,
2016, 7, 12104.
H. M. ElꢀKaderi, J. R. Hunt, J. L. MendozaꢀCortés, A. P.
Côté, R. E. Taylor, M. O'Keeffe and O. M. Yaghi, Science,
2007, 316, 268–272.
5
6
7
8
J. T. Yu, Z. Chen, J. Sun, Z. T. Huang and Q. Y. Zheng, J.
Mater. Chem., 2012, 22, 5369–5373.
Q. Fang, Z. Zhuang, S. Gu, R. B. Kaspar, J. Zheng, J.
Wang, S. Qiu and Y. Yan, Nat. Commun., 2014, 5, 4503.
H. Furukawa and O. M. Yaghi, J. Am. Chem. Soc., 2009,
131, 8875–8883.
G. Das, B. P. Biswal, S. Kandambeth, V. Venkatesh, G.
Kaur, M. Addicoat, T. Heine, S. Vermab and R. Banerjee,
Chem. Sci., 2015, 6, 3931–3939.
9
S. Dalapati, S. Jin, J. Gao, Y. Xu, A. Nagai and D. Jiang, J.
Am. Chem. Soc., 2013, 135, 17310–17313.
Conclusions
We have synthesized two series of highly crystalline and
highꢀsurfaceꢀarea COFs (TPAꢀCOFs and TPTꢀCOFs) based
on Schiff base polycondensations of triarylamines and
trialdehydes having various nitrogen contents and degrees of
planarity and symmetry. We elucidated the chemical
structures of these COFs using FTIR spectroscopy,
elemental analysis, and solid state 13C NMR spectroscopy.
Thermal analyses of these six TPAꢀCOFs and TPTꢀCOFs
revealed that they were thermally stable at temperatures up
to 509ꢀ553 °C. The symmetry, planarity, and nitrogen
content of the monomers all played roles impacting the
crystallinity, BET surface area, and CO2 uptake of the COFs.
For example, when using symmetrical monomers, TPTꢀTPTꢀ
COF (TPTꢀCOFꢀ6), prepared from the most planar
monomers, exhibited a BET surface of 1535.3 m2 g-1,
significantly higher than that of TPAꢀTPAꢀCOF (TPAꢀTPAꢀ
COFꢀ1), produced from the least planar monomers; when
using unsymmetrical monomers, TPAꢀTPPꢀCOF (TPAꢀ
COFꢀ2), prepared from the least planar TPPꢀ3CHO
monomer, provided a BET area of 478.1 m2 gꢀ1 that was
lower than that of TPAꢀTPTꢀCOF (TPAꢀCOFꢀ3), prepared
from the more planar TPTꢀ3CHO monomer. Because some
of the synthesized COFs possessed redoxꢀactive
triphenylamine groups, we tested them for applications in
electrochemical storage. The TPAꢀTPAꢀCOFꢀ1 exhibited the
highest specific capacitance (51.3 F g-1 at 0.2 A g-1) among
our six COFs, consistent with its greater number of redoxꢀ
active groups in the COF unit structure. We also found that a
10 S. Y. Ding, M. Dong, Y. W. Wang, Y. T. Chen, H. Z.
Wang, C. Y. Su and W. Wang, J. Am. Chem. Soc., 2016,
138, 3031–3037.
11 S. Wan, J. Guo, J. Kim, H. Ihee and D. Jiang, Angew.
Chem., Int. Ed., 2009, 48, 5439–5442.
12 Y. Wu, H. Xu, X. Chen, J. Gao and D. Jiang, Chem.
Commun., 2015, 51, 10096–10098.
13 S. Y. Ding, J. Gao, Q. Wang, Y. Zhang, W. G. Song, C. Y.
Su and W. Wang, J. Am. Chem. Soc., 2011, 133, 19816–
19822.
14 H. S. Xu, S. Y. Ding, W. K. An, H. Wu and W. Wang, J.
Am. Chem. Soc., 2016, 138, 11489–11492.
15 S. Lin, C. S. Diercks, Y. B. Zhang, N. Kornienko, E. M.
Nichols, Y. Zhao, A. R. Paris, D. Kim, P. Yang, O. M.
Yaghi1 and C. J. Chang, Science, 2015, 349, 1208–1213.
16 H. Xu, J. Gao and D. Jiang, Nat. Chem., 2015, 7, 905–912.
17 S. Kandambeth, B. P. Biswa, H. D. Chaudhari, K. C. Rout,
S. H. Kunjattu, S. Mitra, S. Karak, A. Das, R. Mukherjee,
U. K. Kharu and R. Banerjee, Adv. Mater., 2017, 29, 1–9.
18 Q. Sun, B. Aguila, J. Perman, L. D. Ear, C. W. Abney, Y.
Cheng, H. Wei, N. Nguyen, L. Wojtas and S. Ma, J. Am.
Chem. Soc., 2017, 139, 2786–2793.
19 F. Xu, S. Jin, H. Zhong, D. Wu, X. Yang, X. Chen, H. Wei,
R. Fu and D. Jiang, Sci. Rep., 2015,
5, 8225.
20 C. R. DeBlase, K. E. Silberstein, T. T. Truong, H. D.
Abruña and W. R. Dichtel, J. Am. Chem. Soc., 2013, 135
,
16821–16824.
8
| Journal Name, [year], [vol], 00–00
This journal is © The Royal Society of Chemistry [year]

Page 9 of 10
Journal of Materials Chemistry A
CREATED USING THE RSC ARTICLE TEMPLATE (VER. 3.1) - SEE WWW.RSC.ORG/ELECTRONICFILES FOR DETAILS
View Article Online
DOI: 10.1039/C8TA04781B
www.rsc.org/xxxxxx | XXXXXXXX
ARTICLE TYPE
21 L. Bai, Q. Gao and Y. Zhao, J. Mater. Chem. A, 2016,
4
,
45 F. Haase, K. Gottschling, L. Stegbauer, L. S. Germann, R.
Gutzler, V. Duppel, V. S. Vyas, K. Kern, R. E. Dinnebier
14106–14110.
and B. V. Lotsch, Mater. Chem. Front., 2017, 1, 1354ꢀ
1361.
22 J. Kim, J. H. Kim and K. Ariga, Joules, 2017,
23 S. Mitra, H. S. Sasmal, T. Kundu, S. Kandambeth, K.
1, 739ꢀ768.
46 L. Zhai, N. Huang, H. Xu, Q. Chen and D. Jiang, Chem.
Commun., 2017, 53, 4242ꢀ4245.
Illath, D. D. Díaz, and R. Banerjee, J. Am. Chem. Soc.
2017, 139, 4513–4520.
,
47 J. Dong, Y. Wang, G. Liu, Y. Cheng, and D. Zhao, Cryst.
Eng. Comm., 2017, 19, 4899ꢀ4909.
48 P. V. Kortunov, M. Siskin, M. Paccagnini, and H.
Thomann, Energy Fuels, 2016, 30, 1223–1236.
49 C. Su, F. Yang, L. Ji, L. Xu and C. Zhang, J. Mater. Chem.
24 Q. Fang, J. Wang, S. Gu, R. B. Kaspar, Z. Zhuang, J.
Zheng, H. Guo, S. Qiu, and Y. Yan, J. Am. Chem. Soc.
2015, 137, 8352–8355.
,
25 L. Bai, S. Z. F. Phua, W. Q. Lim, A. Jana, Z. Luo, H. P.
Tham, L. Zhao, Q. Gao, Y. Zhao, Chem. Commun., 2016,
52, 4128ꢀ4131.
A
, 2014, 2, 20083–20088.
50 C. Su, H. He, L. Xu, K. Zhao, C. Zheng and C. Zhang, J.
Mater. Chem. A, 2017, , 2701–2709.
51 A. M. Khattak, Z. A. Ghazi, B. Liang, N. Ali Khan, A.
26 S. Wan, F. Gándara, A. Asano, H. Furukawa, A. Saeki, S.
K. Dey, L. Liao, M. W. Ambrogio, Y. Y. Botros, X. Duan,
5
S. Seki, J. F. Stoddart and O. M. Yaghi, Chem. Mater.
2011, 23, 4094ꢀ4097.
,
Iqba, L. Li and Z. Tang, J. Mater. Chem. A, 2016,
4,
27 A. P. Côté1, A. I. Benin, N. W. Ockwig, M. O'Keeffe, A. J.
Matzger and O. M. Yaghi, Science, 2005, 310, 1166−1170.
28 X. Ding, J. Guo, X. Feng, Y. Honsho, J. Guo, S. Seki, P.
Maitarad, A. Saeki, S. Nagase and D. Jiang, Angew. Chem.,
Int. Ed., 2011, 50, 1289−1293.
16312–16317.
52 C. R. DeBlase, K. E. Silberstein, T. T. Truong, H. D.
Abruña and W. R. Dichtel, J. Am. Chem. Soc., 2013, 135
16821−16824.
,
29 F. J. UribeꢀRomo, J. R. Hunt, H. Furukawa, C. Klöck, M.
O’Keeffe and O. M. Yaghi, J. Am. Chem. Soc., 2009, 131
4570–4571.
,
30 G. Das, D. B. Shinde, S. Kandambeth, B. P. Biswal and R.
Banerjee, Chem. Commun., 2014, 50, 12615–12618.
31 X. Chen, M. Addicoat, S. Irle, A. Nagai and D. Jiang, J.
Am. Chem. Soc., 2013, 135, 546−549.
32 P. Kuhn, M.Antonietti and A. Thomas, Angew. Chem., Int.
Ed., 2008, 47, 3450−3453.
33 S. Hug, M. B. Mesch, H. Oh, N. Popp, M. Hirscher, J.
Senkerd and B. V. Lotsch, J. Mater. Chem. A, 2014,
5928–5936.
34 X. Feng, X. Ding and D. Jiang, Chem. Soc. Rev., 2012, 41
2
,
,
6010–6022.
35 J. L. Segura, M. J. Mancheño and F. Zamora, Chem. Soc.
Rev., 2016, 45, 5635–5671.
36 Y. Peng, W. K. Wong, Z. Hu, Y. Cheng, D. Yuan, S. A.
Khan and D. Zhao, Chem. Mater., 2016, 28, 5095–5101.
37 T. Y. Zhou, S. Q. Xu, Q. Wen, Z. F. Pang and X. Zhao, J.
Am. Chem. Soc., 2014, 136, 15885–15888.
38 Z. F. Pang, S. Q. Xu, T. Y. Zhou, R. R. Liang, T. G. Zhan
and X. Zhao, J. Am. Chem. Soc., 2016, 138, 4710–4713.
39 S. Karak, S. Kandambeth, B. P. Biswal, H. S. Sasmal, S.
Kumar, P. Pachfule and R. Banerjee, J. Am. Chem. Soc.,
2017, 139, 1856–1862.
40 S. Kandambeth, D. B. Shinde, M. K. Panda, B. Lukose, T.
Heine and R. Banerjee, Angew. Chem. Int. Ed., 2013, 52
,
13052–13056.
41 F. Auras, L. Ascherl, A. H. Hakimioun, J. T. Margraf, F. C.
Hanusch, S. Reuter, D. Bessinger, M. Döblinger, C.
Hettstedt, K. Karaghiosoff, S. Herbert, P. Knochel, T.
Clark and T. Bein, J. Am. Chem. Soc., 2016, 138, 16703–
16710.
42 L. Ascher, T. Sick, J. T. Margraf, S. H. Lapidus, M. Calik,
C. Hettstedt, K. Karaghiosoff, M. Döblinger, T. Clark, K.
W. Chapman, F. Auras and T. Bein, Nat. Chem., 2016, 8,
310–316.
43 A. Halder, S. Kandambeth, B. P. Biswa, G. Kaur, N. C.
Roy, M. Addicoat, J. K. Salunke, S. Banerjee, K. Vanka, T.
Heine, S. Verma and R. Banerjee, Angew. Chem., Int. Ed.
,
2016, 55, 7806–7810.
44 Q. Gao, X. Li, G. H. Ning, H. S. Xu, C. Liu, B. Tian, W.
Tang and K. P. Loh, Chem. Mater., 2018, 30, 1762−1768.
This journal is © The Royal Society of Chemistry [year]
Journal Name, [year], [vol], 00–00 | 9

CREATED USING THE RSC ARTICLEJToEuMrPnLAaTlEo(fVEMR.a3t.0e)r-iSaElsE CWhWeWm.RSisCt.OryRGA/ELECTRONICFILES FOR DETAILS
Page 10 of 10
View Article Online
DOI: 10.1039/C8TA04781B
www.rsc.org/xxxxxx | XXXXXXXX
ARTICLE TYPE
Graphic Abstract
Importance of monomer symmetry, planarity, and nitrogen
content on the crystallinity, surface area, CO2 uptake have been
studied for two series of 2DꢀCOFs.
10 | Journal Name, [year], [vol], 00–00
This journal is © The Royal Society of Chemistry [year]