Reactivity Studies of Metal–Organic Frameworks under Vapor-Assisted Aging: Structural Interconversions and Transformations

Article abstract of DOI:10.1002/ejic.201600907

We systematically studied the chemical reactivities of 13 metal–organic frameworks (MOFs) under vapor-assisted aging (VAG) at room temperature. The MOFs aged in solvent vapor at room temperature showed unexpectedly high reactivities for transformations in

Full text of DOI:10.1002/ejic.201600907

A Journal of
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Title: Reactivity studies of metal-organic frameworks under vapor-assisted aging:
structural interconversions and transformations
Authors: Panjuan Tang; Chunmei Jia; Yujie Jiang; Wei Gong; Xiaocong Cao; Junyi
Yang; Wenbing Yuan
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To be cited as: Eur. J. Inorg. Chem. 10.1002/ejic.201600907
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European Journal of Inorganic Chemistry
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FULL PAPER
Reactivity studies of metal-organic frameworks under vapor-
assisted aging: structural interconversions and transformations
Panjuan Tang,[a] Chunmei Jia,[a] Yujie Jiang,[a] Wei Gong,[a] Xiaocong Cao,[a] Junyi Yang[a] and
Wenbing Yuan*,[a]
[11]
[12]
[13]
Abstract: We systematically studied the chemical reactivity of 13
metal-organic frameworks (MOFs) under vapor-assisted aging
(VAG) at room temperature. The MOFs aged in solvent vapor at
room temperature showed unexpectedly high reactivity to be
transformed into structures with other coordination networks. In
addition, three MOFs reacted with 4,4'-bipyridine to form a 3-
dimensional microporous MOF under VAG conditions at room
temperature.
conditions,
microwave synthesis,
ionothermal,
electrochemical, [14] or mechanochemical[15] approaches. Friščić
and Yuan reported a milder and greener VAG synthesis of
MOFs or CPs. [6,16–18] Notably, solvent VAG can trigger and boost
metal oxides with high lattice energy to react with organic ligand
to produce quantitatively MOFs within hours. However, such
reactions are always difficult either by solution-based or
mechanochemical methods. Meanwhile, products obtained
through in situ VAG show high crystalline quality. [6]
Although extended MOFs or CPs can be prepared using VAG,
the reactivity of MOFs under these conditions has rarely been
[6]
Introduction
explored.
To date, we found that two 1-D CPs, namely,
1,3,5-
[Cu(HBTC)(H2O)3] and [Tb(BTC)(H2O)6] (BTC
=
The discovery and development of new solvent-free or
environment-friendly chemical reactions and preparation
methods have been
chemistry. Among these methods, using less organic solvents,
water as a solvent, or an energy-efficient preparation has been
attracting much attention. Thus, vapor-assisted aging (VAG),
benzenetricarboxylate), can be transformed into HKUST-1 under
DMF VAG for 1 h and 3-D microporous [Tb(BTC)(H2O)] under
ethanol VAG for 30 h.
a research hotspot in contemporary
Herein, we systematically studied the chemical reactivity of
several zinc (or cadmium)-carboxylate frameworks under VAG
conditions. Four organic carboxylic acids, namely, fumaric acid
(H2fum), 1,4-benzenedicarboxylic acid (H2bdc), isonicotinic acid
(Hina), and nicotinic acid (Hna), were chosen to react with zinc
(or cadmium) oxide to obtain13 metal-carboxylate frameworks.
The structural interconversions between these frameworks were
extensively examined, and several of these frameworks were
used as starting materials to react with a neutral ligand, 4,4'-
bipyridine (bipy), to yield a microporous MOF when exposed to
different kinds of solvent vapor. The results show that these CPs
and MOFs have high reactivity under VAG conditions. These
compounds undergo complete reconstruction into other
structures with distinct topologies under appropriate solvent
VAG.
which is
a mild and green synthetic method, has been
extensively investigated.[1–4] In this process, the vapor of water
or several organic solvents is used to drive a reaction to take
place, mimicking the natural mineral formation. Many useful
minerals are naturally formed under atmospheric conditions
such as CO2, H2O vapor, and N2.[5] Although the formation of
these chemicals always involves a very slow chemical reaction,
gas or water vapor plays important roles in these processes.
Compared with conventional solution-based synthesis, VAG
has unique merits, such as no requirement for bulk solvent use,
lower temperature reaction (most of VAG synthesis is at room
temperature), and energy efficiency (to avoid heating or
mechanical energy input). Using a proper pre-treatment method
for starting materials has very important effects on the VAG
reactions, that is, to drive an impossible reaction to take place or
markedly accelerate a reaction to complete within hours.[6]
Results
Metal-organic frameworks (MOFs) or coordination polymers
(CPs) belong to a large family of functional materials and are of
great interest because of their potential applications in methane
and CO2 storage, gas separation, catalysis, sensor, and
Starting materials should be pretreated in VAG. Pre-grinding the
mixture containing all crude materials not only decreases the
particle size but also leads to sufficient contacts between
reactant particles. Four pre-grinding methods were performed,
as follows: pre-MG, manual grinding of reactants; [16] pre-grinding
(pre-G), neat grinding of reactants; pre-ion assisted grinding
(pre-IAG), grinding of starting materials in the presence of small
amounts of salt ; and pre-ion- and -liquid assisted grinding (pre-
ILAG), grinding of starting materials in the presence of small
amounts of salt and small amount of liquid.[6] The pre-ILAG-
liquid is the most efficient method for metal oxides as starting
materials to react with organic ligands. This method can not only
accelerate the corresponding coordination reaction but also
technology.[7,8] MOFs are primarily synthesized using solution-
[10]
based solvothermal,[9] sonochemical,
near-critical water
[a]
Key Laboratory of Tropical Biological Resources of the Ministry of
Education, School of Materials and Chemical Engineering, Hainan
University
Address: 58 Renmin Road, Haikou, 570228, China
E-mail: wbyuan@hainu.edu.cn.
Supporting information for this article is given as a link at the end of
the document.
sometimes determines
a given reaction to occur. Some
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European Journal of Inorganic Chemistry
10.1002/ejic.201600907
FULL PAPER
coordination reactions are difficult to conduct, especially those
between a metal oxide and an organic ligand, and this reaction
was found to occur when some catalytic amount of salt, such as
NH4Cl, were added. [6] In this study, several reactions occurred
completely with 1 min of pre-grinding.
Solvent vapor plays a crucial role in VAG-solvent reaction step.
The kind of solvent vapor sometimes determines the product
structure and its reactivity during VAG. In this study, based on
our previous study on VAG and mechanochemical synthesis of
MOFs, we chose three typical solvent vapors, namely, water,
DMF, and methanol (MeOH), to assist the aging of reactants.
Figure 2 Powder X-ray diffraction patterns for (a) simulated
MATVIN; pre-ion and -liquid assisted grinding (pre-ILAG)
mixtures of (b) H2fum, bipy, and ZnO with DMF for 1 min; (c) 1
and bipy with DMF for 1min; (d) 2 and bipy with DMF for 1 min;
and (e) 3 and bipy with DMF for 1 min; (f) 1 and bipy exposed to
DMF vapor for 3 h; (g) 2 and bipy exposed to DMF vapor for 3 h;
and (h) 3 and bipy exposed to DMF vapor for 3 h. The asterisk
indicates peaks neither present in the patterns of products nor in
the starting materials.
Figure 1 Vapor-assisted aging (VAG) reactions between H2fum
and zinc oxide.
The structural interconversions of the three as-synthesized
VAG of zinc-fumarate coordination networks
zinc-fumarate
frameworks
with
different
dimensional
coordination networks were systematic studied (Figure 1).
Tetrahydrate 1 and dihydrate 2 were converted cleanly to
anhydrous 3 in MeOH vapor within 3 h (Figures S2h and i).
Notably, when tetra-hydrate 1 had been aged for 30 min in
MeOH vapor, dihydrate 2 started to appear despite its small
A summary of VAG reactions between zinc oxide and fumaric
acid is shown in Figure 1. During pretreatment, we added 5 wt%
NH4Cl and 100 μL of water, DMF, or MeOH to the crude mixture
containing H2fum and ZnO. Compounds 1 [Zn(fum)(H2O)4] (1-D,
CSD code IPEZIM)[19] and
3 [Zn(fum)] (3-D, CSD code
amount, and a large amount of unreacted tetrahydrate
1
VUJSAV)[20] were obtained partly after pre-grinding the resulting
mixture for 1 min at 20 Hz (Figures S1b and 1g, respectively).
remained (Figure S2e). After continued aging of the mixture in
MeOH vapor for 20 min (total aging time is 50 min), the products
were mainly anhydrous 3 and a small amount of 2. Moreover, 3
was obtained quantitatively after aging was prolonged to 3 h.
Comparison of the powder X-ray diffraction (PXRD) patterns
(Figures S2e and f) of the products between 30 min and 50 min
of aging shows that dihydrate 2 is an intermediate of the
formation of anhydrous 3 from 1. Upon formation of 2, 2 was
rapidly converted to anhydrous 3. MeOH vapor efficiently drove
the continuous dehydration reaction, 1→2→3, accompanied with
a loss of the coordinated water molecules from the coordinated
zinc centers. Thus, zinc-fumarate coordination structures were
However, the same mechanochemical reaction without NH4Cl
[20,21]
took at least 20 min to complete.
The addition of NH4Cl
remarkably accelerated the reaction between H2bdc and zinc
oxide, and the corresponding products were obtained during
pretreatment. Additionally, we added a small amount of 1:1
mixture of H2O and MeOH into the crude mixture and then pre-
ground them for
1 min. A mixture containing dihydrate
compound
2
[Zn(fum)(H2O)2] (2-D, CSD code VUJSEZ)[20]
tetrahydrate 1 and anhydrous 3 was obtained (Figure S1g). We
also attempted to obtain a pure compound 2 by VAG by altering
the ratio of the mixture solvent and the VAG time. However,
unsatisfactory results were obtained. Thus, we extended the
grinding of the pre-ILAG-H2O:MeOH(1:1) mixture for another of
30 min, resulting in the formation of dihydrate compound 2
(Figure S1e).[20]
reconstructed in MeOH vapor to
a higher dimensionality.
However, such similar dehydrated reaction of zinc-
benzenedicaboxylate frameworks under VAG-MeOH did not
occur. This phenomenon will be discussed later.
The reverse VAG reactions, 3→2, 3→1, or 2→1, in water
vapor did not occur even after 5 days of aging. However,
interestingly, immersion of 3 or 2 in excess liquid water for 24 h
led to a complete formation of compound 1 (Figures S2j and k).
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European Journal of Inorganic Chemistry
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This phenomenon is probably due to the lower relative humidity
(90%) of VAG-H2O, which was not sufficient to trigger such
hydrated reactions.
DMF vapor for 24 h (Figs. S4e and S4f). Aging in H2O vapor for
24 h resulted in the conversion of 6 and 7 to 5. However, the
reverse dehydrated transformation, 5→7, did not occur even
after 72 h of aging in MeOH vapor (Figure S4i). These findings
indicate the role played by the nature of the solvent on product
formation.[2]
The described interconversions and transformations between
the three zinc-fumarate frameworks clearly indicate their high
lability under VAG. Such lability could be attributed to the
coordination-driven assembly of water molecules.[22] Thus, the
zinc-fumarate framework VAG were used as starting materials to
explore other MOFs. Thus, we introduced 4,4'-bipyridine (bipy)
as an auxiliary ligand, which could coordinate with zinc centers
to generate pillared MOFs (Figures 1 and 2).
Pre-grinding the mixture of compound 1, 2, or 3 and bipy for
1 min yielded products which could not be identified by PXRD
(Figures 2c–e). However, strikingly,
a pure mixed-ligand
framework 4, [Zn2(fum)2(bipy)] (CSD code MATVIN),23 was
obtained quantitatively to expose the above pre-ground crude
mixtures in DMF vapor for 3 h (Figures 2f–h). Bipy with higher
coordination ability than water drove compounds 1, 2, and 3 to
be dehydrated completely. This process was accompanied with
a total structural change, shown by the increased degree of
dimensionality and micropore formation from nonporous
structures. Moreover, the pre-ILAG-DMF of the mixture, that is,
ZnO, H2fum, and bipy in the required stoichiometric ratio of
1:1:0.5 for 1 min, also yielded 4 (Figure 2b).
VAG of zinc-benzenedicaboxylate coordination networks
1,4-benzenedicarboxylic acid (H2bdc), with longer phenyl linker
between two neighboring carboxylate groups compared with
fumaric acid (H2fum), may show a different VAG reaction
behavior. Thus, we studied the structural interconversions of
zinc-benzenedicarboxylate frameworks under VAG. An overview
of VAG reactions between H2bdc and zinc oxide or several zinc-
benzenedicarboxylate coordination networks are shown in
Figure 3.
For the pretreatment step, we added 5 wt% NH4Cl and 100 μL
of water, DMF, or MeOH to the crude mixture containing H2bdc
and ZnO. Pre-grinding this mixture for 1 min at 20 Hz
surprisingly yielded two Zn-bdc coordination compounds,
namely, [Zn(bdc)(H2O)2] (5, 1-D, CSD code DIKQET)[24] and
microporous [Zn(bdc)(H2O)]•DMF (6, 2-D, CSD code
GECXUH),[25] which were obtained partly except for complex 7
(Figs. S3b and 3d). However, the same mechanochemical
reaction without NH4Cl took at least 20 min to complete.[26]
Adding NH4Cl remarkably accelerated the reaction between
H2bdc and zinc oxide. Exposing the pre-ILAG-MeOH mixture to
MeOH vapor for 6 h resulted in complex 7 [Zn(bdc)(H2O)](CSD
code IFABIA)[27] (Figure S3g).
After obtaining the three coordination complexes, the MOF
interconversions between these complexes were found to be
induced by solvent VAG at room temperature. Based on the
solvent used in the pre-ILAG-liquid step, three solvent vapors,
namely, H2O, DMF, and MeOH, were selected to assist in the
in situ interconversions between 5, 6, and 7 at room temperature
(Figs. 3 and S4). Compound 6 was easily transformed to 5 or 7
within 24 or 72 h by aging in H2O or MeOH vapor. Their reverse
reactions, 7 and 5 to 6, were easily induced by aging 7 or 5 in
Figure 3 VAG reactions between H2bdc and zinc oxide. The
asterisk indicates peaks neither present in patterns of products
nor in the starting materials.
Most of the interconversions were formal dehydration and
rehydration reactions. The change from 7 or 6 to 5 at the
molecular level involved the addition of one water molecule per
Zn center and a change in carboxylate coordination from
bidentate bridging to monodentate. Furthermore, aging both 5
and 7 in DMF vapor led to the complete formation of compound
6. DMF in compound 6 served as guest molecules existing in
channels, and a hydrogen bond exists between a DMF molecule
and a coordinated water molecule. Thus, DMF molecules mostly
serve as template in forming the channels around them. Finally,
6 was converted into 7 by aging in MeOH vapor for 72 h (Figure
S4h).
In all six interconversions between 5, 6, and 7 under VAG,
only 5→7 could not proceed even after several days of aging in
MeOH vapor at room temperature. However, this transformation,
5→7, could be completed by mechanochemical grinding for
40 min in the presence of small amount of MeOH. By contrast,
6→7 transformation was impossible to conduct even with
prolonged grinding time.[26] These results show that the
dehydrated transformations are more difficult to occur even in
the presence of high mechanical energy input. However,
strikingly, conversions from 6 to 7 could be induced under VAG,
not under mechanochemical conditions.
structural interconversions induced by water and MeOH vapors
between zinc-benzenedicaboxylate and zinc-fumarate
frameworks shows two interesting results. First, the rehydrated
A comparison of
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European Journal of Inorganic Chemistry
10.1002/ejic.201600907
FULL PAPER
transformations of zinc-benzenedicaboxylate frameworks are
possible, but those of zinc-fumarate are not. Second, the
also be completed under mechanochemical grinding for 30–
90 min.[32]
dehydration
transformation
of
zinc-benzenedicaboxylate
frameworks, 5→7, is impossible, contrary to those of zinc-
fumarate frameworks, 1→2, 2→3, and 1→3.
VAG of zinc-nicotinate coordination networks
The overall VAG reaction scheme of zinc-nicotinate frameworks
is similar to that of Hina and ZnO (Figure 5). Both efficient pre-
ILAG-H2O and -MeOH yielded a discrete tetrahydrate complex
VAG of zinc- and cadmium-isonicotinate coordination
networks
12, [Zn(na)2(H2O)4] (nicotinic acid: Hna, 0-D, CSD code
[33]
The overall VAG reactions between isonicotinic acid (Hina) and
ZnO are shown in Figure 4. Using the pre-ILAG-H2O to pretreat
the crude mixture which contained Hina, ZnO, and a catalytic
amount of NH4Cl, for 1 min yielded a discrete tetrahydrate
complex 8, [Zn(ina)2(H2O)4] (0-D, CSD code INICZN,[28] Figure
S5b). For the pre-ILAG-MeOH starting materials, a porous triply
interpenetrated diamondoid network 9, [Zn(ina)2] (3-D, CSD
code JUKVEQ), [29] was obtained partially (Figure S5d). When
we used CdO instead of ZnO to react with Hina, the pre-ILAG-
H2O of the crude reactants yielded partially the analogous
KODYUX)
and a 2-D open framework 13, [Zn(na)2] (CSD
[34]
code JOMWAJ)
, respectively (Figures. S9b and S9d).
Complex 12 has previously been prepared from Hna and ZnO
by mechanochemical grinding for 30 min,[35] whereas 13 was
only previously synthesized in solvothermal condition using
Zn(ClO4)2•6H2O and 3-cyanopyridine.34
[30]
discrete complex [Cd(ina)2(H2O)4] (10; CSD code INICZN),
which is isostructural to 8. Pre-ILAG-DMF pretreatment led to
the microporous doubly interpenetrated diamondoid network 11,
[Cd(ina)2(H2O)]•DMF (3-D, CSD code AVAQIX, [31] Figure S6d).
Figure 5 VAG reactions between Hna and zinc oxide
Interestingly, clean interconversions between the discrete 12
and polymeric form 13 were also possible under VAG conditions
(Figure 5). Aging for 18 h in MeOH vapor led to the clean
conversion of 12 to 13, and the reverse transformation occurred
partly by aging 13 in H2O vapor for 6 h (Figure S10).
Discussion
We used three solvent vapors, namely, H2O, DMF, and MeOH,
in the four series of structural interconversions and
transformations of metal-organic frameworks under VAG. In the
VAG-H2O-driven rehydration reactions, that is, 6→5, 7→5, 9→8,
11→10, and 13→12, water vapor provided water molecules as
ligands. Meanwhile, the DMF vapor served as a template in
1→4, 5→6, 7→6, and 10→11, in which DMF molecules existed
in the pores of complexes 6 and 11 as guest molecules. MeOH
vapor usually led to the dehydration reactions, namely, 1→2,
2→3, 1→3, 6→7, 8→9, and 12→13. However, MeOH molecule
is neither a reactant nor a template in these reactions.
Figure 4 VAG reactions between zinc oxide or cadmium oxide
and isonicotinic acid
The
VAG-driven
metal-isonicotnicate
frameworks
interconversions between compounds 8 and 9, or 10 and 11,
occurred completely. Exposing discrete tetrahydrate compounds
8 and 10 to MeOH and DMF vapors, respectively, for 8 and 3
days resulted in partial yields of their porous diamondoid
coordination networks, 9 and 11 (Figures S7 and 8). For the
reverse VAG reactions, 9→8 and 11→10, water vapor drove
them to react completely for 1 h and 3 days, respectively. These
structural interconversions between 8 and 9, or 10 and 11, could
To our knowledge, the driving force for the VAG-MeOH-
induced MOF interconversions may be dominated by the
formation of the least soluble product. The solubilities of
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European Journal of Inorganic Chemistry
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FULL PAPER
complexes 5, 6, and
7
in MeOH are 1.21, 0.56, and
bar in a solution-based reaction to drive the product layers or
particles away and facilitate a continuous efficient contact
between reactant particles. When giving a further aging, product
layers or product particles aggregate together, and the resulting
product with a high crystallinity forms. Thus, in situ aging in
solvent vapor is a mass mobility process, and solvent vapor not
only markedly increases mobility rate but also contributes to the
crystal growth of the product.
0.51 mmol L−1 respectively.[26] Thus, the transformation of 6→7
is possible under MeOH vapor aging, but 5→7 cannot occur at
room temperature probably because of a high energy barrier
between complexes 5 and 7 such that a certain amount of
energy would be required to overcome the activation energy
needed for this reaction. Therefore, this reaction can take place
under mechanochemical grinding because of an additional high
mechanical energy input.[26] To further confirm the solubility with
a fundamental effect on these VAG-MeOH transformations, we
found that the solubility of 8 in MeOH (1.92 mmol L−1) was
higher than that of 9 (0.92 mmol L−1).[32]. Thus, 8→9 took place
under MeOH VAG.
Figure 6 Scanning electron micrographs for complex 6 obtained
by (a) exposing 5 to DMF vapor for 24 h and (b) pre-ILAG for 1
min. Scale bars are 20 μm.
Figure 7 Description of the VAG process. The black sections
show the product formation. The green arrow indicates VAG.
Solvent vapor generally not only drives the MOF
interconversion or transformations to take place in a VAG
process but also contributes to the growth of product crystal.
Figure 6 shows the scanning electron micrographs of compound
6 produced by VAG-DMF for 24 h and pre-ILAG-DMF for 1 min.
A comparison between Figures 6a and Figure 6b shows clearly
that the VAG-DMF product is composed of large crystal particles
with clearly defined faces and edges.
Conclusions
The results show that VAG is
a milder, lower energy
consumption, low-temperature alternative for the synthesis of
MOFs compared with other conventional solution-based or
mechanochemical methods. More interestingly, several metal-
organic frameworks show their high labilities under VAG
conditions. Their structural interconversions and transformations
occur upon exposure to solvent vapors at room temperature.
Furthermore, solvent vapor aging of a metal-organic framework
to react with other ligands results in the reconstruction of their
structures. Finally, a more efficient pre-treatment method, that is,
pre-ILAG, can induce a rapid quantitative formation of 1-D, 2-D,
or 3-D metal-organic coordination networks within 1 min. We are
currently perusing the VAG preparation of other functional metal-
organic frameworks and their VAG reactivity studies.
Further, we attempted to provide a clear and representative
description of the whole VAG process including pretreatment
step and subsequent aging in solvent vapor, and the results are
shown in Figure 7. Initial pre-grinding of reactants is necessary
to facilitate sufficient contact between them. The three pre-
grinding methods, pre-G, pre-LAG and pre-ILAG, to be used is
primarily dependent on the reaction activity of the raw materials.
Pre-G and pre-LAG generally do not lead to some reactions to
occur between reactants during pretreatment. However, pre-
ILAG sometimes not only drives a reaction to take place
especially for metal oxides with high lattice energy,[6,17] but also it
always leads to a quick reaction.
As illustrated in Figure 7, VAG is needed for examples that
show no reaction or a partial reaction in the pretreatment step.
First, initial VAG drives a contact reaction to occur. Then,
continued aging in solvent vapor leads to the formation of a
product layer, which can be dispersed to other locations by
solvent vapor, that is, mass transfer process takes place. Here,
solvent vapors in VAG may play a role as the magnetic stirring
Experimental Section
General Methods All reagents and solvents were purchased from
commercial sources and used without further purification. PXRD data for
samples were taken on a flat plate in the 2θ range of 4°–40° using a
Bruker AXS D8 advance X-ray powder diffractometer equipped with Cu
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European Journal of Inorganic Chemistry
10.1002/ejic.201600907
FULL PAPER
Kα radiation (γ= 0.15405 nm). Starting materials were pretreated by pre-
grinding in a Retsch MM200 mixer mill.
[11] I. A. Ibarra, P. A. Bayliss, E. Pérez, S. Yang, A. J. Blake, H. Nowell, D.
R. Allan, M. Poliakoff and M. Schröder, Green. Chem. 2012, 14, 117-
122.
[12] D. M. Taddei, D. A. Steitz, P. D. J. A. Bokhoven and D. M. Ranocchiari,
Chem. Eur. J. 2016, 22 , 3245-3249.
Pretreatment Procedure Metal oxide (1 mmol) and 1 mmol of organic
acid (for Hna and Hina, 2 mmol), NH4Cl (5 wt.%), and 100 μL of solvent
were added into a 25 ml stainless steel milling jar. Then, this crude
mixture was ground with a Retsch MM200 shaking mill in the steel vessel
with a 10 mm steel ball at 20 Hz for 1 min. The addition of catalytic
amount of NH4Cl is unnecessary for samples with metal-organic
frameworks used as starting materials to react with other N-contained
neutral ligand under VAG conditions.
[13] J. Liu, X. Zou, C. Liu, K. Cai, N. Zhao, W. Zheng and G. Zhu, Dalton,
Cryst. Eng. Comm. 2016, 18, 525-528.
[14] S. Sachdeva, A. Pustovarenko, E. J. R. Sudhölter, F. Kapteijn, L. C. P.
M. Smet and J. Gascon, Cryst. Eng. Comm. 2016.
[15] P. A. Julien, K. Užarević, A. D. Katsenis, S. A. J. Kimber, T. Wang, O. K.
Farha, Y. Zhang, J. Casaban, L. S. Germann, M. Etter, R. E. Dinnebier,
S. L. James, I. Halasz and T. Friščić. J. Am. Chem. Soc. 2016, 138,
2929–2932.
Standard VAG Process The above pre-treated crude mixture was put in
a culture dish (60 mm diameter). Then, this crude mixture was placed in
a capped glass desiccator (180 mm diameter) along with a beaker
containing 20 mL of solvent. The reactant mixture was aged in the
solvent vapor generated spontaneously from the liquid solvent added for
a specific time at room temperature (28 °C).
[16] C. Jia, J. Wang, X. Feng, Q. Lin and W. Yuan, Cryst. Eng. Comm. 2014,
16, 6552.
[17] C. Mottillo, Y. Lu, M. H. Pham, M. J. Cliffe, T. O. Dob and T. Friščić,
Green. Chem. 2013, 15, 2121-2131.
[18] Cristina Mottillo and Tomislav Friščić, Angew. Chem. Int. Ed. 2014, 53,
7471 –7474.
[19] H-Z. Xie, Y-Q. Zheng and K-Q. Shou, J. Coord. Chem. 2010, 27,491-
519.
[20] T. Friščić and L. Fábián, Cryst. Eng. Comm. 2009, 11, 743-745.
[21] F. C. Strobridge, N. Judas and T. Frisci, Cryst. Eng. Comm. 2010, 12,
2409–2418.
Acknowledgements
The authors would like to acknowledge the NSFC (Grant nos.
21561009, 21241008, and 21061005) and the International Joint
Project of Hainan Province (Grant no. KJHZ2013-18) for their
financial support. The Instrumental Analysis Center of Hainan
University is also acknowledged.
[22] K. Campbell, C. J. Kuehl, M. J. Ferguson, P. J. Stang and R. R.
Tykwinski, J. Am. Chem. Soc. 2002, 124, 7266-7267.
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[24] G. Guilera and J. W. Steed, Chem. Common. 1999, 1563–1564.
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European Journal of Inorganic Chemistry
10.1002/ejic.201600907
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Strctural interconversion
and transormation made
easy: Metal–organic
frameworks (MOFs) are
surprisingly reactive under
vapor-assisted aging
(VAG) at room temperature
and can undergo various
rearrangements (see
picture).
MOF VAG interconversions
Panjuan Tang,[a] Chunmei
Jia,[a] Yujie Jiang,[a] Wei
Gong,[a] Xiaocong Cao,[a]
Junyi Yang[a], and Wenbing
Yuan*[a]
Page No. – Page No.
Title: Reactivity studies of metal-organic frameworks under vapor-assisted aging: structural interconversions and
transformations
This article is protected by copyright. All rights reserved