Structural reorganization in a hydrogen-bonded organic framework

Article abstract of DOI:10.1039/C8NJ02738B

Self-recognition of 3,3′,5,5′-azobenzenetetracarboxylic acid drives the formation of a grid-like anionic hydrogen-bonded framework with channels occupied by organic cations. This supramolecular solid is capable of reorganizing its connectivity in the pres

Full text of DOI:10.1039/C8NJ02738B

View Article Online
View Journal
NJC
Accepted Manuscript
This article can be cited before page numbers have been issued, to do this please use: J. Castells-Gil, N.
M. Padial and C. Martí-Gastaldo, New J. Chem., 2018, DOI: 10.1039/C8NJ02738B.
This is an Accepted Manuscript, which has been through the
Volume 40 Number
1 January 2016 Pages 1–846
Royal Society of Chemistry peer review process and has been
accepted for publication.
NJC
Accepted Manuscripts are published online shortly after
New Journal of Chemistry
www.rsc.org/njc
A journal for new directions in chemistry
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 1144-0546
PAPER
Jason B. Benedict et al.
The role of atropisomers on the photo-reactivity and fatigue of
diarylethene-based metal–organic frameworks
rsc.li/njc

Please do not adjust margins
New Journal of Chemistry
Page 1 of 7
View Article Online
DOI: 10.1039/C8NJ02738B
Journal Name
ARTICLE
Structural reorganization in a hydrogen-bonded organic
framework
Received 00th January 20xx,
Accepted 00th January 20xx
Javier Castells-Gil,a Natalia M. Padiala and Carlos Martí-Gastaldo*,a
DOI: 10.1039/x0xx00000x
Self-recognition of 3,3’,5,5’-azobenzenetetracarboxylic acid drives the formation of a grid-like anionic hydrogen-bonded
framework with channels occupied by organic cations. This supramolecular solid is capable of reorganizing its connectivity
in the presence of specific guests into a different crystalline architecture by sequential dissolution and recrystallization.
www.rsc.org/
favoured by the lability of the supramolecular interactions that
interconnect the components to enable molecular recognition
processes for dynamic equilibria between supramolecular
Introduction
Crystal engineering of molecular solids has been pivotal to the
tremendous advance in the design of functional frameworks
with properties such as porosity, catalysis, ion exchange,
proton transport, luminescence or magnetism. This has been
well illustrated for crystalline porous solids like Metal-Organic
Frameworks (MOFs)1 and Covalent Organic Frameworks
(COFs),2 for which the spatial distribution of molecular
components within a porous structure dictates the properties
of the material.
architectures. We report an anionic 2D hydrogen-bonded
framework built from carboxylic acid supramolecular dimers
that features 1D channels covered in H-bond acceptor sites.
This provides a chemically adaptable environment capable of
reorganizing its connectivity in the presence of other
molecular components to form different H-bonded networks.
Our results suggest that dynamic self-assembly is controlled by
effective interplay of the supramolecular interactions between
the host and the cationic guest, that are responsible for the
crystallization of a different framework topology.
In turn, Hydrogen-bonded Organic Frameworks (HOFs) are
based exclusively on the assembly of organic blocks by
supramolecular non-covalent interactions. Purely organic
crystals offer important advantages like straightforward
synthesis, solvent processability, ease of regeneration by
recrystallization or low molecular weight.3-6 Compared to
MOFs and COFs based on robust coordination and covalent
bonds, H-bonds are weaker, and the resulting structures
feature lower chemical and structural stability. This is a key
drawback for their use as porous materials. Although there are
Experimental Section
Materials and Methods
5-nitroisophthalic acid (98%), guanidine hydrochloride, 98%
(GND·HCl) and aminoguanidine hydrochloride, 99%
(AmGND·HCl) were purchased from Sigma-Aldrich and used as
received. N,N-Dimethylformamide (≥ 99.8%) and propan-2-ol
(≥ 99.9%) were purchased from Scharlab. Ultrapure water
from Milli-Q equipment was used when required. All reagents
and solvents were used without any previous purification
unless specified. Carbon, nitrogen and hydrogen contents
were determined by microanalytical procedures using a LECO
CHNS. Infrared spectra were recorded in an Agilent Cary 630
FTIR Spectrometer directly with no need of KBr pellets.
Thermogravimetric analysis were carried out with a Mettler
Toledo TGA/SDTA 851 apparatus between 25 and 800 °C under
ambient conditions (10 °C·min−1 scan rate and an air flow of 30
mL·min−1). 1H and 13C NMR spectra were run on a Bruker
DRX500 spectrometer. XRD patterns were collected in a
PANalytical X'Pert PRO diffractometer using copper radiation
(Cu Kα = 1.5418 Å) with an X’Celerator detector, operating at
40 mA and 45 kV. Profiles were collected in the 2° < 2θ < 40°
range with a step size of 0.017°. PXRD was collected in a
PANalytical X'Pert PRO diffractometer using copper radiation
previous
examples
demonstrating
the
ability
of
supramolecular frameworks to maintain their structural
integrity upon solvent removal,7-16 thermal activation often
results in the collapse of the architecture for complete loss of
porosity. Unlike their rigid counterparts, that more often can
retain the original structure upon guest exchange or solvent
removal, HOFs are more flexible and can undergo controlled
structural changes based on the directionality of H-bonds and
their ability to break and re-form cooperatively in presence of
specific guests. Hence, their main source of instability can be
used as an asset to access dynamic responses which are not
accessible to more robust frameworks. This process is
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 1
Please do not adjust margins

Please do not adjust margins
New Journal of Chemistry
Page 2 of 7
View Article Online
DOI: 10.1039/C8NJ02738B
ARTICLE
Journal Name
(Cu Kα = 1.5418 Å) with an X’Celerator detector, operating at
40 mA and 45 kV. Profiles were collected in the 2° < 2θ < 40° Single-Crystal X-ray Diffraction
range with a step size of 0.017°.
Suitable crystals of
1
and
2
were selected, mounted on a
Mitagen micromont by using paraffin oil and measured on a
SuperNova, Single source at offset, Sapphire3 diffractometer.
Synthesis of 3,3’,5,5’-azobenzenetetracarboxylic acid (H4abtc)
H4abtc was synthesized according to a reported method.17 In a The crystal was kept at 120.00(10) K during data collection.
typical procedure, 5-nitroisophtalic acid (19 g) and sodium The structure was solved in Olex219 by using the ShelXT20
hydroxide (50 g) were suspended in 250 mL of Milli-Q water structure solution program using Intrinsic Phasing and refined
and reacted at 60 °C with continuous stirring for 1 hour. Next, with the ShelXL21 refinement package using Least Squares
glucose (100 g) was dissolved in 100 mL of warm water and the minimisation.
resulting solution was added dropwise to the yellow slurry that
became dark brown due to reduction of the nitro groups. The
Results and Discussion
mixture was left to cool down for 30 minutes followed by
exposure to an air stream for 16 hours with continuous stirring
Synthesis and structure of [H2abtc][DMA]2
at room temperature. Next, the crude was cooled in an ice
3,3’,5,5’-azobenzenetetracarboxylic acid (H4abtc; C16H10N2O8)
bath prior to isolation of the solid by filtration with vacuum.
was synthesised according to a reported method.18 This
Finally, the solid was dissolved in 250 mL of water and acidified
organic molecule displays
with HCl 37% to produce an orange precipitate. This was
four
exodentate
in
planar
isolated by filtration, thoroughly washed with water and dried
in an oven (92% yield). Elemental analysis for C16H10N2O8: Calc.
C (53.64), H (2.81), N (7.86); found: C (52.59), H (3.02), N
(7.75). Spectroscopic data matched those quoted in the
bibliography.18
functionalities
rectangular
a
disposition (C2h symmetry)
well-suited to direct self-
assembly
in
two
dimensions (Figure 1).
Reaction of H4abtc in a
Synthesis of [H2abtc][DMA]2 (1)
Figure 1. Structure of abtc4-
.
H4abtc (229.3 mg; 0.64 mmol) was suspended in 4 mL of
DMF:i-PrOH (8:2) in a rubber-lined capped glass vial. The
orange suspension was heated up to 150 °C at a rate of 0.2
°C·min-1, held for 48 hours and allowed to cool down at a rate
of 0.4 °C·min-1. This results in the formation of orange crystals
that were isolated by filtration and rinsed with 45 mL of DMF
(3x15 mL) and 45 mL of i-PrOH (3x15 mL). The product was
dried in a desiccator under vacuum at room temperature.
Yield: 69.5%. Elemental analysis for [C16H8N2O8][(CH3)2NH2]2:
Calc. C (53.57), H (5.39), N (12.49); found: C (53.57), H (5.12), N
(12.55%). 1H-NMR (500 MHz, DMSO-d6): 8.65 (t, J = 1.4 Hz, 2H),
8.52 (d, J = 1.4 Hz, 4H), 2.56 (s, 12H). 13C NMR (125 MHz,
DMSO-d6, DEPT) δ: 167.5 (C), 151.4 (C), 136.0 (C), 132.2 (CH),
125.1 (CH), 33.7 (CH3).
mixture
dimethylformamide and propan-2-ol at 150 °C yields
[H2abtc][DMA]2 (DMA+= dimethylammonium) (
). Compound
of
N,N-
1
1
crystallizes in the triclinic space group P-1 as orange, prismatic
crystals of around 100 µm in size. It is built from partially
deprotonated H2abtc2- linkers forming H-bonded syn-syn
C=O…H-O
carboxyl
dimer
synthons,
sitting
at
centrosymmetrically related positions. The d(D-A) distances
range from 2.465(2) to 2.476(2) Å, values characteristic of
strong ionic H-bonds (Table SI4), similar to those reported for
other H-bonded organic frameworks.22-25 Packing of the
anionic grid-like layers is controlled by strong π–π stacking
between neighbouring aromatic rings. The rings feature a
parallel offset arrangement with inter-centroid distances close
to 3.5 Å (Figure SI20). As shown in Figure 2, this results in the
formation of a layered structure that displays 1D channels
along the [100] direction that are occupied by DMA+ cations
for overall charge balance, which originate from
decarbonylation of DMF at 150 °C. These are linked to the
organic framework by weaker N-H…O=C H-bonds with the
central amine group (2.7 Å). The presence of organic cations
was also demonstrated by 1H NMR for polycrystalline samples.
Synthesis of [H2abtc][GND]2·2H2O (2)
100 mg of compound
1 were soaked in 5 ml of a guanidine
hydrochloride solution in ethanol (96%) and allowed to stand
at room temperature for several weeks refreshing the solution
every day. After two weeks, single-crystals of
2 suitable for
single-crystal X-ray diffraction were obtained. (See ESI SI2 for
NMR data).
NMR spectrum of
1 in DMSO confirms the presence of two
DMA+ molecules per H2abtc linker, consistent with the
structural study (Figure SI1). FT-IR spectrum endorses the
presence of the characteristic vibrational modes of DMA+ and
aromatic C-H groups in the organic linker (Figure SI10). Phase
purity of the bulk material was proved by X-ray powder
diffraction (Figure SI14).
Recrystallization in the presence of different cations
For each time, 15 mg of compound
1 was soaked in 5 mL
equimolar solutions of GND·HCl and AmGND·HCl (0.05 mol·L-1,
respectively) in ethanol (96%). The solution was refreshing
every day during 60 days. After that, the orange solid was
washed with 5 mL of absolute ethanol for 3 times, the solvent
was removed by syringe and air drying.
2 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Please do not adjust margins
New Journal of Chemistry
Page 3 of 7
View Article Online
DOI: 10.1039/C8NJ02738B
Journal Name
ARTICLE
Figure 2. Structure of [H2abtc][(DMA]2. Interlayer packing results in 1D channels (a) that are occupied by DMA+ cations interleaved between the grid-like
anionic layers (b).
exposure to solvents
As shown in Figure SI15, thermogravimetric analysis confirms
that the solid is stable up to 200 °C where it shows a first
weight loss of 20.4% close to 240 °C, that coincides with the
loss of two molecules of DMA. Decomposition of the
remaining anion is likely related to the gradual decomposition
of the framework that extends from 350 °C to the highest
temperature measured. This behaviour is similar to previously
reported ionic cation/anion hydrogen-bonded frameworks,
with decompositions taking place between 240 and 300 °C.23
Figure 3a shows the variable-temperature PXRDs collected
between 30-200 °C.
1 undergoes slight compression upon
heating, close to 6% in volume according to the refinement of
the unit cell form experimental data (Figure SI22). This is
accompanied by progressive amorphization that becomes
more drastic at 200 °C. The collapse of the structure is non-
reversible. Exposure of the amorphous solid to an atmosphere
rich in water promoted the formation of a different crystalline
phase (Figure 3b). FT-IR suggested the presence of water
molecules (Figure SI12) due to the broad band observed
around 3400 cm-1. This is also confirmed by the thermal
decomposition of this crystalline phase that displays a similar
profile than
1 except for the low-temperature regime, with a
first weight loss below 100 °C of about 33% that likely
corresponds to the release of water molecules (Figure SI18).
Though we repeatedly tried to isolate this new phase by
modifying the synthetic conditions, we did not manage to
isolate single crystals that enable to elucidate the structure of
this phase. However, the weight loss step at 240 °C
corresponding to the loss of dimethylamine molecules is lower
Figure 3. (a) Variable-temperature PXRDs of 1 at 30-200 °C suggesting progressive
compression of the unit cell alongside non-reversible amorphization close to 200 °C.
See Figure SI22 for unit cell refinement. (b) Crystalline conversion into a different phase
upon water exposure.
Thermal stability and structural changes with temperature and
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 3
Please do not adjust margins

Please do not adjust margins
New Journal of Chemistry
Page 4 of 7
View Article Online
DOI: 10.1039/C8NJ02738B
ARTICLE
Journal Name
Figure 4. Structure of [H2abtc][GND]2·EtOH. (a) Packing of the layers following a ..ABAB.. sequence. (b) Internal structure of the layers accommodating GND+ cations in the cavities
via H-bond with H2abtc2-. (c) Inclusion of solvent molecules disrupts 2D connectivity in type-A layers for the formation of 1D zig-zag segregated chains.
than that calculated for the release of two dimethylamine architectures in solution.26,27,30 No single-crystals could be
molecules (Calc: 15.1%, Exp: 8.5) which suggests a partial obtained when AmGND+ was employed likely due to the higher
decomposition of the framework upon exposure to water.
Although very small in our case, this structural flexibility is not
dilution imposed by the lower solubility of this salt.
crystallizes in the centrosymmetric P21/c space group. Similar
, there is one crystallographically independent H2abtc2-
2
surprising for HOFs. Ionic H-bonds combine sufficient strength to
1
and directionality to endow the framework with the flexibility unit for the assembly. Two types of planes are stacked
necessary to adapt its structure to solvent removal or guest following an ..ABAB.. sequence into a layered structure (Figure
inclusion.23,26-28 Compared to the structural changes in water,
1
4a). Packing is controlled by the inclusion of GND+ cations
retains its original structure when soaked in DMF and organic across type A and B layers. They act as H-bond donors to form
solvents like EtOH or i-PrOH and slightly changes in MeOH C=O…H-N and N_H…O-H bonds with the terminal carboxylate
(Figure SI23), with minimum changes in the chemical groups of the azobenzenetetracarboxylic acid in the
composition or the IR spectrum of the final solid. This suggests neighbouring layers. See Figure SI27 and Table SI6 for H-bond
that structural reorganization might be linked to the use of distances. Type B layers (Figure 4b) display a 2D network
solvents with high hydrogen bond donation (HBD) ability. The assembled by the formation of syn-syn ionic H-bond
observed behaviour coincides with the trend of HBD values connections equivalent to those in 1, d(D-A) of 2.427(6) or
calculated by stepwise multiple linear regression for these 2.519(6) Å, for a similar grid-like topology. Empty space in the
solvents: H2O > MeOH > EtOH > i-PrOH > DMF.29 We argued plane is here occupied by three GND+ molecules that are linked
this selective structural response could be also extended to the to the layer by H-bonds with the carboxylic groups pointing
incorporation of other cations to the structure of
1
.
inwards the cavity (Figure SI28). As for type A layers, the
inclusion of GND+ is accompanied by water molecules from
solution that breaks 2D connectivity. As a result, the lattice is
segregated into 1D zig-zag chains whose connectivity is also
dictated by H-bonded carboxylic acid dimers between
alternative polyaromatic units to produce cavities that are
occupied by two GND+ cations and two water molecules. As
shown in Figure SI28, their position within the layer is fixed by
a network of supramolecular interactions that involve two
H2O…chain and one H2O…GND+ H-bonds. The inclusion of
solvent molecules in the cavities seems to be the main factor
responsible for disrupting the connectivity in type-A layers.
This leads to a distorted packing that precludes the formation
Crystallization of [H2abtc][GND]2·2H2O
We selected guanidinium (GND+) and aminoguanidinium
(AmGND+) cations because their size is slightly bigger than
DMA+ and have three and four H-bonding donor sites
compared to only one in DMA+. As-made crystals of
1 were
soaked in saturated ethanolic solutions of the chloride salts of
GND+ and AmGND+ separately (0.1 and 0.05 mol·L-1) and left to
stand in static conditions with continuous refreshing of the
solutions every 24 hours. After one week GND+ triggers the
formation of crystals of [H2abtc][GND]2·2H2O (2) with a
different morphology (Figure SI9). Formation of the inclusion
complex seems to follow the procedure of an addition of GND+
to the pre-organized DMA+ network, that might induce a self-
assembly equilibrium between both cations towards the
selective formation of a specific supramolecular architecture
with lower solubility. Similar dynamic exchanges between
molecular components have been reported for supramolecular
of the 1D channels originally present in
performed on the solids obtained after the exchange process
with GND+ or AmGND+ showed a similar profile to that of
but
1. TG analyses
1
with two weight loss steps before the total decomposition of
the framework, that we ascribed to the loss of DMA+ and GND+
or AmGND+ molecules, respectively (Figure SI16,17). To further
investigate the reorganization of the supramolecular
4 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Please do not adjust margins
New Journal of Chemistry
Page 5 of 7
View Article Online
DOI: 10.1039/C8NJ02738B
Journal Name
ARTICLE
framework in the presence of GND+, we repeated the landscape with four conformers accessible at the experiment
experiments for
handful of crystals with intermittent conditions (Figure SI30).20
a
monitoring in the optical microscope. There is no real
retention of single crystallinity and incorporation of the cation
Conclusions
can rather be explained by sequential re-dissolution of
1, with
the solution becoming yellow as result of progressive leaching
of H2abtc2- anions, followed by nucleation and growth of
In summary, [H2abtc][DMA]2 behaves as
a chemically
2
adaptable framework capable of undergoing self-organization
in the presence of cationic guests like guanidinium and
upon incorporation of GND+ to the structure. The progress of
the cation replacement was also monitored by analysing the
aminoguanidinium. Exposure of the original framework to a
evolution of the NMR of crystals of 1 soaked in 0.1 M solutions
concentrated solution of the first results in the spontaneous
formation of a new supramolecular architecture from a
solution of exchanging components, assisted by reversible
formation of labile H-bonds. NMR studies also indicate that
this new framework is preferably assembled with
aminoguanidium from a mixture of cations likely due to a
balance between the size and density of H-bond donor
acceptor sites in the cation. This kinetic array cannot be sorted
out by crystallization likely due to higher dilution and similar
solubility of the interconverting components. This same
structural adaptability can be extended to more complex
frameworks in which additional chemical functions can be
incorporated to guide selective interactions with a broader
range of guests.
of GND+ with time (SI2, Table SI1, Figure SI5). Inclusion of GND+
results in a concomitant decrease of the DMA+ NMR signal at
different time intervals. Equilibrium is achieved after 13 days
for an overall substitution percentage of DMA+ by GND+ of 84%
(Figure 5, dashed lines).
Conflicts of interest
There are no conflicts to declare.
Acknowledgements
Figure 5. Dynamic replacement of DMA+ cations in crystals of 1: soaked in GND+ [0.1 M]
during one month (dashed lines) or in an equimolar mixture of GND+/AmGND+ [0.05 M]
during two months (solid lines). Cation percentages in the sample were extracted from
the NMR of dissolved crystals at different time intervals. See SI2 for more details.
This work was supported by the Spanish MINECO (CTQ2017-
83486-P) and the Generalitat Valenciana (GV/2016/137). C.M.-
G. and J.C.-G. thank the Spanish MINECO for a Ramón y Cajal
Fellowship and FPI Scholarship (CTQ2014-59209-P). N.M.P.
thanks the Junta de Andalucía for postdoctoral fellowship P10-
FQM-6050.
NMR study of DMA replacement with time
For a better understanding of this dynamic cation recognition
process, we carried out a similar study by soaking crystals of
1
in 0.05 M equimolar solutions of GND+ and AmGND+ cations
for two months. Monitoring of the reaction by 1H and 13C NMR
at different times (Figures SI7, SI8 and Table SI2) indicates that
DMA+ cations are exclusively replaced with AmGND+ (overall
ratio of 65%) with no recognition of GND+ (Figure 5, solid
lines). Unfortunately, we could not isolate single-crystals
during the experiment suggesting that the concentration of
the cation might play a crucial role in the growth of the
[H2abtc]2- anionic layers upon inclusion of GND+ or AmGND+
cations. Still, there are several reasons that might justify the
preference for AmGND+ from solution. As shown in Figure SI29
AmGND+ offers more H-bond donor and acceptor sites than
GND+ or DMA+. Furthermore, it is comparatively bigger in size
and features richer conformational flexibility. The calculated
Van der Waals volumes for DMA+ and GND+ display quite close
values, 60 and 57 Å3, whereas AmGND+ is close to 15% bigger
with 70 Å3. Whilst there are only two conformers accessible for
DMA+ and GND+, AmGND+ offers a richer conformational
Notes and references
1
H. Furukawa, K. E. Cordova, M. O'Keeffe and O. M. Yaghi,
Science, 2013, 341, 1230444–1230444.
N. Huang, P. Wang and D. Jiang, Nat. Rev. Mater., 2016, 1,
16068.
2
3
4
A. M. Beatty, Coord. Chem. Rev., 2003, 246, 131–143.
B. Moulton and M. J. Zaworotko, Chem. Rev., 2001, 101,
1629–1658.
5
6
7
8
V. A. Russell, C. C. Evans, W. Li and M. D. Ward, Science,
1997, 276, 575–579.
P. Brunet, M. Simard and J. D. Wuest, J. Am. Chem. Soc.,
1997, 119, 2737–2738.
A. Comotti, S. Bracco, G. Distefano and P. Sozzani, Chem.
Commun., 2009, 47, 284–286.
W. Yang, A. Greenaway, X. Lin, R. Matsuda, A. J. Blake, C.
Wilson, W. Lewis, P. Hubberstey, S. Kitagawa, N. R.
Champness and M. Schröder, J. Am. Chem. Soc., 2010, 132,
14457–14469.
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 5
Please do not adjust margins

Please do not adjust margins
New Journal of Chemistry
Page 6 of 7
View Article Online
DOI: 10.1039/C8NJ02738B
ARTICLE
Journal Name
9
R. V. Afonso, J. Durão, A. Mendes, A. M. Damas and L. Gales,
Angew. Chem. Int. Ed., 2010, 49, 3034–3036.
10
11
12
Y. He, S. Xiang and B. Chen, J. Am. Chem. Soc., 2011, 133,
14570–14573.
M. Mastalerz and I. M. Oppel, Angew. Chem. Int. Ed., 2012,
51, 5252–5255.
R. Natarajan, L. Bridgland, A. Sirikulkajorn, J.-H. Lee, M. F.
Haddow, G. Magro, B. Ali, S. Narayanan, P. Strickland, J. P. H.
Charmant, A. G. Orpen, N. B. McKeown, C. G. Bezzu and A. P.
Davis, J. Am. Chem. Soc., 2013, 135, 16912–16925.
P. Li, Y. He, H. D. Arman, R. Krishna, H. Wang, L. Weng and B.
Chen, Chem. Commun., 2014, 50, 13081–13084.
T.-H. Chen, I. Popov, W. Kaveevivitchai, Y.-C. Chuang, Y.-S.
Chen, O. Daugulis, A. J. Jacobson and O. Š. Miljanić, Nat.
Commun., 2014, 5, 5131.
13
14
15
16
17
18
H. Wang, Bin Li, H. Wu, T.-L. Hu, Z. Yao, W. Zhou, S. Xiang and
B. Chen, J. Am. Chem. Soc., 2015, 137, 9963–9970.
R. S. Patil, D. Banerjee, C. Zhang, P. K. Thallapally and J. L.
Atwood, Angew. Chem. Int. Ed., 2016, 55, 4523–4526.
S. Ameerunisha and P. S. Zacharias, Journal of the Chemical
Society, Perkin Transactions 2, 1995, 1679–1682.
A. Dhakshinamoorthy, M. Alvaro, H. Chevreau, P. Horcajada,
T. Devic, C. Serre and H. García, Catal. Sci. Technol., 2012, 2,
324–330.
19
O. V. Dolomanov, L. J. Bourhis, R. J. Gildea, J. A. K. Howard
and H. Puschmann, J. Appl. Cryst., 2009, 42, 339–341.
G. M. Sheldrick, Acta Crystallogr A Found Adv, 2015, 71, 3–8.
G. M. Sheldrick, Acta Crystallogr C Struct Chem, 2015, 71, 3–
8.
20
21
22
23
24
S. A. Dalrymple and G. K. H. Shimizu, J. Am. Chem. Soc., 2007,
129, 12114–12116.
P. Dechambenoit, S. Ferlay, N. Kyritsakas and M. W. Hosseini,
J. Am. Chem. Soc., 2008, 130, 17106–17113.
N. Roques, G. Mouchaham, C. Duhayon, S. Brandès, A.
Tachon, G. WEBER, J. P. Bellat and J.-P. Sutter, Chem-Eur J.,
2014, 20, 11690–11694.
25
G. Mouchaham, N. Roques, W. Khodja, C. Duhayon, Y.
Coppel, S. Brandès, T. Fodor, M. Meyer and J.-P. Sutter,
Chem-Eur J., 2017, 23, 11818–11826.
26
27
C.-L. Chen and A. M. Beatty, J. Am. Chem. Soc., 2008, 130,
17222–17223.
K. Biradha, D. Dennis, V. A. MacKinnon, C. V. Krishnamohan
Sharma and M. J. Zaworotko, J. Am. Chem. Soc., 1998, 120,
11894–11903.
28
W. Xiao, C. Hu and M. D. Ward, J. Am. Chem. Soc., 2014, 136,
14200–14206.
29
30
Y. Marcus, Chem. Soc. Rev., 1993, 22, 409–416.
D. Dumitrescu, Y. M. Legrand, F. Dumitrascu, M. Barboiu and
A. Van Der Lee, Cryst. Growth Des., 2012, 12, 4258–4263.
6 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Page 7 of 7
New Journal of Chemistry
View Article Online
DOI: 10.1039/C8NJ02738B
Çꢀꢁꢂꢃ ꢄꢅ ꢄꢆꢇꢃꢆꢇꢈ ꢃꢆꢇꢉꢊ
{ꢀꢁꢂꢃꢄꢀꢅ ꢆꢇꢈꢉꢈ ꢇ ꢂ ꢉꢊꢀ ꢋꢌꢋꢍꢌꢎꢌꢎꢍꢃꢏꢐ ꢑꢀꢇꢐꢀꢇꢀꢉꢀꢉꢄꢏꢅꢏꢄꢑ ꢒꢓꢁꢈꢅ ꢏꢅꢈꢔ ꢓꢈꢀꢁꢔꢕ ꢏ ꢆꢄꢈꢔꢃꢁꢈꢖꢀ ꢏꢇꢈ ꢇꢈꢅ
ꢊꢓꢔꢄ ꢆꢀꢇꢃꢑ ꢇꢔꢀꢔ ꢂꢄꢏꢗꢀꢘ ꢄꢖ ꢅꢏꢙꢏꢑꢁꢀ ꢂ ꢚꢇꢔꢀꢄꢆ ꢈꢇꢆ ꢕꢉꢄꢚꢅꢉꢚꢄꢏꢁ ꢄꢀ ꢄꢆꢏꢇꢈꢐꢏꢉꢈ ꢇ ꢑꢓ ꢄꢀꢅꢄꢓꢕꢉꢏꢁꢁꢈꢐꢏꢉꢈ ꢇ
ꢈꢇ ꢉꢊꢀ ꢙꢄꢀꢕꢀꢇꢅꢀ ꢂ ꢆꢚꢏꢇꢈꢔꢈꢇꢈꢚꢗ ꢅꢏꢉꢈ ꢇꢕꢛ