A highly stable polyoxovanadate-based Cu(i)-MOF for the carboxylative cyclization of CO2with propargylic alcohols at room temperature

Article abstract of DOI:10.1039/d0gc02812f

A novel polyoxovanadate-based copper(i)-organic framework, [CuI(bib)]4{VV4O12} (V-Cu-MOF, bib = 1,4-bis(1H-imidazoly-1-yl)benzene), is facilely synthesized under mild hydrothermal conditions. The structure of the V-Cu-MOF is constructed from a cyclic {V4O12}4- polyanion cluster and a 1D chain Cu(i)-MOF ([CuI(bib)]+). The presence of the {V4O12}4- cluster stabilizes the Cu(i)-MOF with Cu(i) as the center, thereby improving the stability of the V-Cu-MOF and enabling it to stably exist in various solvents and pH = 2-12 solutions. Additionally, the V-Cu-MOF as a heterogeneous catalyst can catalyze the carboxylative cyclization of CO2 and propargylic alcohols to high value-added α-alkylidene cyclic carbonates at room temperature, and the conversion and selectivity are almost 100%. More importantly, no obvious decrease in the yield of the α-alkylidene cyclic carbonate is observed after ten cycles. These results indicate the excellent catalytic activity and sustainability of the V-Cu-MOF. Research on the mechanism of the catalytic reaction suggests that the high-density Cu(i) sites in the V-Cu-MOF are the catalytically active centers for activating the CC bonds of propargylic alcohols. To the best of our knowledge, this is the first example of polyoxometalate-based metal-organic framework catalyst for catalyzing the conversion of CO2 to value-added α-alkylidene cyclic carbonates at room temperature. This journal is

Full text of DOI:10.1039/d0gc02812f

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DOI: 10.1039/D0GC02812F
ARTICLE
A highly stable polyoxovanadate-based Cu(I)–MOF for the
carboxylative cyclization of CO
2
with propargylic alcohols at room
temperature
Received 00th January 20xx,
Accepted 00th January 20xx
Hong-Rui Tian, Zhong Zhang, Shu-Mei Liu, Tian-Yi Dang, Zhuo Li, Ying Lu and Shu-Xia Liu*
DOI: 10.1039/x0xx00000x
I
{VV
O12} (V-Cu-MOF, bib = 1,4-bis(1H-imidazoly-1-
A novel polyoxovanadate-based copper(I)–organic framework, [Cu (bib)]
4
4
yl)benzene), is facilely synthesized under mild hydrothermal conditions. The structure of V-Cu-MOF is constructed by cyclic
12}4- polyanion cluster and 1D chain Cu(I)-MOF ([Cu (bib)] ). The presence of {V 12}4- cluster stabilizes the Cu(I)-MOF
O
I
+
{V
4
O
4
with Cu(I) as the center, thereby improving the stability of the V-Cu-MOF and enabling it to stably exist in various solvents
and pH = 2-12 solutions. Additionally, the V-Cu-MOF as a heterogeneous catalyst can catalyze the carboxylative cyclization
of CO and propargylic alcohols to high value-added α-alkylidene cyclic carbonates at room temperature, the conversion and
2
selectivity are almost 100%. More importantly, no obvious decrease in the yield of the α-alkylidene cyclic carbonate is
observed after ten cycles. These results indicate the excellent catalytic activity and sustainability of V-Cu-MOF. Researching
the mechanism of the catalytic reaction suggests that the high-density Cu(I) sites in the V-Cu-MOF are the catalytically active
centers for activating the C≡C bonds of propargylic alcohols. To the best of our knowledge, this is the first example of
polyoxometalate-based metal–organic frameworks catalyst for catalyzing the conversion of CO to value-added α-alkylidene
2
cyclic carbonates at room temperature.
Introduction
Carbon dioxide (CO
2
), as a greenhouse gas, has been considered
A number of homogeneous catalysts, including inorganic
as the main cause of global warming due to its growing salts,25-29 organic salts,
30-32
organic phosphorous,
and ionic liquid etc.,
33, 34
transition
have been
is developed to catalyze the cycloaddition of propargylic alcohols
1
, 2
35-37
38-41
concentration in the atmosphere.
with the toxic phosgene and carbon monoxide, CO
recognized as green, cheap and inexhaustible C1 feedstock.
As a result, transforming CO into high value-added chemicals is excellent catalytic activity, they suffer from the difficulty in
an effective strategy that not only reduces the content of CO postreaction separation and catalyst reusability.
Meanwhile, comparing metal complexes,
2
3
-5
2
with CO . Although these homogeneous catalysts exhibit
2
2
,
6
-8
but also makes full use of this renewable resource. Currently, Heterogeneous catalyst is an ideal candidate to resolve above
many methods have been reported for chemical conversion of these problems. Hence, various heterogeneous catalysts, such
9
, 10
42, 43
44, 45
CO
2
, mainly including the photocatalytic reduction of CO
2
,
as metal nanoparticles,
composite catalysts,
and metal–
1
1-13
46-49
carboxylation of terminal alkynes with CO
2
,
cycloaddition of organic frameworks (MOFs) etc.,
have been explored to
1
4-17
aziridines or epoxides with CO
cyclization of propargylic alcohols with CO
which the cyclization of propargylic alcohols with CO
2
,
and carboxylative catalyze the cyclization of CO
2
with propargylic alcohols. Among
2
, 18-21
2
etc.,
among them, MOFs are a class of crystalline materials with definite
is one of composition and structure, which are constructed by metal ions
2
5
0, 51
the most efficient route because the obtained products α- or clusters and organic ligands.
MOFs have been abstracted
alkylidene cyclic carbonates are an important class of much attention because their inherent crystal properties that
heterocyclic compounds in organic synthesis and can provide the nature and distribution of catalytically active
2
2, 23
pharmaceutical chemistry.
high temperature or CO pressure are necessary to realize this substrate molecules. Recently, many Ag-based and {CuI}
cyclization reaction owe to the thermodynamic stability and cluster-based MOFs catalysts have been employed for the
However, highly active catalysts, sites and the potential interactions between catalytic sites and
5
2
2
2
4
46-49, 53
kinetic inertness of CO
2
.
2
carboxylative cyclization of propargylic alcohols with CO .
In spite of these catalysts show high catalytic effects and the
unique advantages of MOFs, they are associated with the
utilization of noble metals, stoichiometric additives, low
stability, poor recyclability and harsh reaction conditions (high
Key Laboratory of Polyoxometalate Science of the Ministry of Education, College
of Chemistry, Northeast Normal University, Changchun, Jilin 130024, P. R.
China. Email: liusx@nenu.edu.cn.
Electronic Supplementary Information (ESI) available: [details of any supplementary
information available should be included here]. See DOI: 10.1039/x0xx00000x
temperature and CO
2
pressure). Therefore, developing efficient,
highly stable and sustainable non-noble metal-based
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ARTICLE
heterogeneous catalyst to achieve the cyclization reaction of
Journal Name
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DOI: 10.1039/D0GC02812F
propargylic alcohols with CO
challenging.
2
under mild conditions still remains
Polyoxometalate-based metal–organic frameworks (POMOFs)
are a kind of crystalline hybrid materials that constructed by
MOFs and POMs, which have attracted great interest in the field
of catalysis because they combine the advantages of MOFs and
5
4, 55
POMs.
enhance the stability of the original MOFs,
for the sustainability of the MOFs catalyst in catalytic reaction.
In this work, we successfully synthesized novel
polyoxovanadate-based copper(I)–organic framework,
12} (V-Cu-MOF, bib = 1,4-bis(1H-imidazoly-1-
yl)benzene), which exhibits high solvent and acid/base
stabilities. V-Cu-MOF as heterogeneous catalyst can
effectively and selectively catalyze the carboxylative cyclization
of various terminal propargylic alcohols with CO to high value-
In addition, the introduction of POMs into MOFs can
5
6-58
which is crucial
a
I
V
[
4 4
Cu (bib)] {V O
a
2
added α-alkylidene cyclic carbonates at room temperature.
More importantly, V-Cu-MOF shows excellent recyclability, and
the yield of α-alkylidene cyclic carbonate is still up to 97% after
ten cycles. To our knowledge, this is the first example of
POMOFs catalyst for the cyclization of propargylic alcohols with
CO
2
at room temperature.
12}4- polyanion cluster. (b) Bimetallic
4
O
V O12}. (c) Ligand bib. (d) Three connection modes of ligand bib.
4 4
Fig. 1 The structure of V-Cu-MOF. (a) {V
octanuclear cluster {Cu
e) The 3D frameworks of V-Cu-MOF. Hydrogen atoms are omitted for clarity.
(
Results and discussion
Crystal structure and characterizations of V-Cu-MOF
photoelectron spectroscopy (XPS), and two typical peaks with
bonding energies of 517.5 eV and 932.26 eV can be assigned to
Yellow strip V-Cu-MOF crystals were synthesized from NaVO
Cu(NO ) ·3H O, bib and N H ·H O under mild hydrothermal
3 2 2 2 4 2
conditions. Single crystal X-ray diffraction analysis reveals that
V-Cu-MOF crystallizes in a triclinic space group of P-1 (Table S1).
The structure of V-Cu-MOF contains a cyclic {V
cluster that constructed from four distorted VO
linked by the vertex-sharing of O atoms, and all V atoms in the
cluster exhibit tetrahedral coordination geometry, coordinated
4 12
by four oxygen atoms (Fig. 1a). The {V O } cluster in V-Cu-
MOF severs as a tetradentate ligand to bond to four Cu atoms
by two terminal O atoms and two bridging O atoms, thus
3
,
5
5, 60
V(V) 2p3/2 and Cu(I) 2p3/2, respectively (Fig. S1).
The phase
purity of V-Cu-MOF is demonstrated by the experimental
powder X-ray diffraction (PXRD), which is matched well with the
simulated peaks from the crystallographic studies (Fig. S2). The
Fourier transform infrared (FTIR) spectrum of V-Cu-MOF is
4
-
4
O
12} polyanion
tetrahedron
4
-1
shown in Fig. S3. The characteristic bands in 930-1000 cm and
-
1
6
00-910 cm are attributed to ν(V=O) and ν(V-O-V),
6
1
-1
respectively. The bands in the region of 1100-1600 cm arise
4
-
6
2
from ν(C=C) of ligand bib.
The stability of V-Cu-MOF
The structural stability of catalyst is important for its practical
application, thus we systematically investigate the stability of V-
Cu-MOF. The thermal stability of V-Cu-MOF is confirmed by
thermogravimetric analysis (TGA), it can be seen that V-Cu-MOF
exhibits high thermal stability, up to 350 °C (Fig. S4).
Subsequently, we explore the solvent and acid/base stabilities
of V-Cu-MOF by soaking it in various organic solvents (Toluene,
DCM = dichloromethane, Dioxane, MeOH = methanol, ACN =
acetonitrile, DBU = 1,8-diazabicyclo-[5.4.0]underc-7-ene) for 7
days and pH aqueous solutions (pH = 1-13) for 12 hours. The
PXRD patterns (Fig. 2) and FTIR spectra (Fig. S5) of the
experimental V-Cu-MOF are well consistent with those of the
fresh prepared V-Cu-MOF, suggesting that V-Cu-MOF has
excellent solvent stability and acid/base stability (pH= 2-12). To
our knowledge, the stability
4 4
obtaining a bimetallic octanuclear cluster {Cu V O12} (Fig. 1b).
There are two kinds of copper ions (Cu1 and Cu2) that adopt “T-
type” coordination geometry in the cluster (Fig. 1b). The Cu1 ion
is ligated by two N atoms from two bib molecules and one
4
-
terminal O atom from {V
4
O
12
}
cluster, and the Cu2 ion is
coordinated by two N atoms from two bib molecules and one
4
-
4
bridging O atom from {V O12} cluster (Fig. 1b). In addition, the
ligand bib corresponds to a linear bidentate ligand (Fig. 1c),
which has three linking modes in V-Cu-MOF (Fig. 1d). Each
bimetallic {Cu V O12} cluster is further linked by eight ligands bib
4 4
to a 3D framework (Fig. 1e).
Bond valence sum (BVS) calculations59 reveal that oxidation
states of all V and Cu ions in compound V-Cu-MOF are +5 and
+
1, respectively (Table S2). Moreover, the oxidation states of V
and Cu ions in V-Cu-MOF are further confirmed by X-ray
of V-Cu-MOF is significantly higher than the most Cu(I)-MOFs
1
3, 48, 49
that have been reported,
which may be attributed to the
2
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Fig. 2 (a) PXRD patterns of V-Cu-MOF after immersing in various solvents for 7 days; (b) PXRD patterns of V-Cu-MOF after immersing in different pH solutions for 12 hours.
introduction polyoxovanadates into the Cu(I)-MOF, similar the production of some by-products with elevating the
6
3
phenomenon have been observed and discussed for the other temperature. Hence, the proper reaction temperature is 25 °C,
5
6-58
kinds of POMOFs as well.
Catalytic performance of V-Cu-MOF for the cyclization of of the product exhibits a rising trend as the pressure of CO
propargylic alcohols with CO
enhanced from 0.1 MPa to 0.8 MPa (Fig. 3b). However, the
improvement of yield turns slower after exceeding 0.4MPa, so
the moderate CO pressure is 0.4 MPa. Then the effect of
and the CO
2
pressure is explored at this temperature. The yield
2
is
2
In view of the excellent stability and high-density Cu(I) active
sites, the catalytic activity of V-Cu-MOF was explored by the
2
amount of DBU is investigated. The yield is increased with the
amount of DBU added, but the enhancement of yield is
unworthy when the amount of DBU added over 30 μL (Fig. 3c),
indicating the suitable amount of DBU is 30 μL (0.2 mmol).
Finally, the dependence of yield on the reaction time is studied,
and the result is recorded in Fig. 3d. It can be seen that the yield
of α-alkylidene cyclic carbonate can reach 99% within 10 hours,
thus the appropriate reaction time is 10 hours. According to the
above experimental results, the optimal reaction conditions of
V-Cu-MOF catalyzes the cyclization of propargylic alcohols with
2
carboxylative cyclization of propargylic alcohols with CO . 2-
methyl-3-butyn-2-ol (1a, 1.0 mmol) was selected as model
substrate to optimize the reaction conditions, and the catalytic
reaction was conducted in ACN (1.0 mL), 0.4 MPa CO
mesitylene as internal standard (1 mmol), and catalyst
0.025mmol, 2.5% mol) at 25 °C. For a better dispersion in ACN,
2
pressure,
(
the V-Cu-MOF crystals were ground and the Brunauer–
Emmett–Teller (BET) surface area of used V-Cu-MOF was 4.2
2
m /g (Fig. S6). The catalytic process was monitored by gas
chromatography with flame ionization (GC-FID) and the product
1
CO
CO
2
to produce α-alkylidene cyclic carbonate are 25 °C, 0.4 MPa
pressure, 30 μL of DBU as co-catalyst and 10 hours.
was identified by H NMR spectra. As shown in Table S3, the
2
individual catalyst V-Cu-MOF and other raw materials (NaVO
Cu(NO 3H O and bib) were hardly to catalyze the reaction
Table S3, Entry 1-5). It should be noted that V-Cu-MOF showed
3
,
Next, we investigate the catalytic behaviors of V-Cu-MOF
toward the cyclization of a series of propargylic alcohols with
CO under the optimal reaction conditions. As shown in Table 1,
2
3
)
2
·
2
(
negligible activity together with co-catalyst triethylamine (TEA)
or diisopropylethylamine (DIPEA) (Table S3, Entry 7-8), but
when DBU was added as co-catalyst in combination with V-Cu-
MOF, the yield of the desired product α-alkylidene cyclic
carbonate can reach to 99% (Table S3, Entry 9). In addition, the
DBU was alone employed as catalyst, it was ineffective for the
reaction (Table S3, Entry 6), indicating that V-Cu-MOF was an
excellent catalyst for the cyclization of propargylic alcohols with
CO to generate α-alkylidene cyclic carbonate and there was
2
some synergistic effect between V-Cu-MOF and DBU.
Subsequently, the examinations of other reaction
parameters (reaction temperature, CO pressure, amount of
2
DBU, and reaction time) were performed based on the catalytic
system of V-Cu-MOF/DBU, and the results were summarized in
Fig. 3. To clearly display the influence of these parameters, the
reaction time was reduced to 6 hours. Firstly, the yield of the
target product α-alkylidene cyclic carbonate is decreased with
increasing reaction temperature (Fig. 3a), which is attributed to
V-Cu-MOF could catalyze the transformation of terminal
propargylic alcohols with different substituents (methyl, ethyl,
sec-butyl, cyclopentyl, and cyclohexyl) to the corresponding
high value-added α-alkylidene cyclic carbonates in almost
quantitative yield. It should be noted that the yield of 2h
decreased to 88% under identical conditions, which may be
caused by the steric hindrance effect. However, the yield of 2h
can be improved to 95% by appropriately extending the
reaction time (12 hours). These results demonstrated that V-Cu-
MOF is an efficient and selective catalyst for the carboxylative
cyclization of CO
carbonates.
2
with propargylic alcohols to α-alkylidene cyclic
Recyclability of V-Cu-MOF
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Fig. 3 The influences of reaction conditions on the carboxylative cyclization of
propargylic alcohols with CO . (a) The effect of reaction temperature. (b) The effect
of CO pressure. (c) The effect of DBU amount. (d) The effect of reaction time.
2
2
Reaction conditions: 1a (1.0 mmol), V-Cu-MOF (0.025 mmol), mesitylene (internal
standard, 1.0 mmol), DBU (0.2 mmol), ACN (1.0 mL), 25°C, 6 hours. The yields were
determined by GC.
Having identified highly catalytic activity and wide generality
exhibited by V-Cu-MOF, the recyclability of the catalyst is
subsequently investigated by employing 1a as model substrate,
which is vital for practical application. Firstly, a leaching test was
performed to further confirm the heterogeneity of the catalyst
V-Cu-MOF. As shown in Fig. 4a, the removal of the V-Cu-MOF by
Fig. 4 (a) Catalyst V-Cu-MOF filtered after 2 h. (b) Recycling tests for 1a with CO
2
cycloaddition using V-Cu-MOF. (c) PXRD patterns of V-Cu-MOF: before and after catalytic
reactions. (d) FTIR spectra of V-Cu-MOF: before and after catalytic reactions. (e, f) XPS
spectra of Cu(I) and V(V) in V-Cu-MOF: before and after catalytic reactions.
Table 1 Carboxylic cyclization of various propargylic alcohols with CO
2
over V-
centrifugation after 2 hours, and the resulting solution was
maintained for another 10 hours under the same conditions,
but no additional 2a was produced. To our delight, there was no
significant decrease in the catalytic activity of V-Cu-MOF after
ten runs (the yield of 2a was maintained at 99-97%) (Fig. 4b),
indicating excellent sustainability of V-Cu-MOF. The PXRD
patterns and FTIR spectra of the recovered catalyst matched
well with the fresh catalyst (Fig. 4c, d), suggesting its structural
integrity. In addition, there was no obvious difference in XPS
results, which demonstrated the well-maintained oxidation
states of V ions and Cu ions in the catalyst before and after the
catalytic reaction (Fig. 4e, f). These results indicate that V-Cu-
MOF has highly structural stability and reusability.
Cu-MOF. a
Compared with the reported heterogeneous catalysts for the
cyclization of propargylic alcohols with CO , the V-Cu-MOF
2
showed the following advantages. First of all, V-Cu-MOF
exhibited comparable catalytic activity with noble metal-based
catalysts (Table S4, Entry 1-3). Secondly, V-Cu-MOF
demonstrated high stability and recyclability (the yield of 2a can
reach 97% after ten runs), whereas the leaching of active
species was severe in certain MOF-based catalysts (Table S4,
Entry 9-12). Third, with the assistance of catalytic amount of
additives, V-Cu-MOF could achieve the cycloaddition of
a
2
Reaction conditions: substrate (1 mmol), catalyst (0.025 mmol), 0.4MPa CO , DBU
(
0.2mmol), ACN (1 mL), 25ºC, 10hours. Yield was determined by GC and mesitylene
2
propargylic alcohols with CO at room temperature, while high
reaction temperature (Table S4, Entry 4-8) or stoichiometric
b
as internal standard. 12hours.
4
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additives (Table S4, Entry 1-2) were required in some catalytic catalytically active site for the cyclization reaction.VAielwthAortuiclgehOntlhinee
systems. Therefore, V-Cu-MOF can be considered as a green homogeneous CuI catalyst exhibits compaDrOaIb: l1e0.c1a0t3a9l/yDt0icGCac0t2i8v1it2yF
and sustainable catalyst for the carboxylative cyclization of with the V-Cu-MOF catalyst, the V-Cu-MOF shows excellent
propargylic alcohols with CO
alkylidene cyclic carbonates.
2
to obtain high value-added α- recyclability without significant decrease in yields over ten
catalytic cycles (Fig. 4b). Moreover, Cu(I) is widely employed as
Reaction mechanism of V-Cu-MOF for catalyzing the cyclization of catalyst for activation the C≡C bond in organic synthesis,67 thus
propargylic alcohols with CO
2
we deduce that Cu(I) in V-Cu-MOF is the catalytically active site
that activates the C≡C bond of the substrate 1a.
Based on the above discussion, a possible mechanism for the
It is well known that the activations of the C≡C bond and
hydroxyl group in the propargylic alcohols are considered as
two crucial processes for the carboxylative cyclization of the
propargylic alcohols with CO
experimental results and the reported literatures,
speculate that the DBU is used for activation the hydroxyl group
of the propargylic alcohol and Cu(I) in V-Cu-MOF is utilized for
activation the C≡C bond of the propargylic alcohol in our V-Cu-
MOF/DBU catalytic system. To confirm our assumptions, firstly,
the propargylic alcohol 1a, and the mixture 1a/DBU and 1a/V-
2
carboxylative cyclization of propargylic alcohols with CO by V-
Cu-MOF is proposed in Scheme 1. Initially, in the system of DBU
and V-Cu-MOF (a), the DBU abstracts proton from the alcoholic
hydroxyl of the propargylic alcohol by forming hydrogen
bonding and the Cu(I) in V-Cu-MOF interacts with the C≡C bond
of the propargylic alcohol through its empty orbital and π
4
7, 64
2
.
According to our
2
7
we
electron of C≡C bond to generated the intermediate b. Then CO
is inserted via the resulting alcohol anion nucleophilic attack on
the carbon atom of CO , the intermediate c is obtained.
Subsequently, the intramolecular cycloaddition of the transition
2
1
2
Cu-MOF are examined by H NMR spectra analysis and the
results are recorded in Fig. 5. The H signal of O-H in 1a appears
1
6
8
c produces the vinylcopper intermediate d. Finally, the α-
alkylidene cyclic carbonate is generated by proto-demetallation
and the catalyst returns to the original (a).
at δ = 5.30 ppm and presents a sharp single peak (Fig. 5a). The
1
H signal of the mixture of 1a/V-Cu-MOF (Fig. 5b) is similar to
that of O-H in 1a, suggesting that V-Cu-MOF cannot activate the
hydroxyl group of the substrate 1a. However, the H signal of
1
the mixture of 1a/DBU shifts obviously and changes into a broad
peak (Fig. 5c), which indicates that DBU can activate the
alcoholic hydroxyl through the formation of hydrogen
Conclusions
6
5
bonding. Subsequently, a series of control experiments are
carried out using ligand bib, [Et N] {V 2H O and CuI as
catalyst, respectively, to confirm the active site of the V-Cu-
MOF in the carboxylative cyclization of 1a with CO (Table S5).
4
4
4
O
12
}
·
2
2
[
Et
4
N]
4
{V
4
O
12
6
}
·
2H
2
O (Fig. S7) was synthesized according to the
6
4-
literature, in which {V
4
O
12} had the same structure as that in
V-Cu-MOF. These results demonstrate that ligand bib and
Et N] {V 2H O as catalyst exhibit no catalytic activity
[
4
4
4
O
12
}
·
2
under the optimal reaction conditions (Table S5, Entry 1-2).
However, the yield of 2a is 99% when the CuI is used as catalyst
In conclusion, we synthesized a novel POVs-based MOF, V-Cu-
MOF, and its unique composition and structure makes it have
high solvent and acid/base stabilities. The V-Cu-MOF can
heterogeneously catalyze the cyclization of various terminal
2
propargylic alcohols with CO to obtain high value-added α-
alkylidene cyclic carbonates at room temperature, displaying
excellent catalytic activity and selectivity. More importantly, the
V-Cu-MOF exhibits significant sustainability, the yield of α-
alkylidene cyclic carbonate is still as high as 97% after ten cycles.
This work demonstrates that the recyclability of MOFs-based
catalyst can be improved by introducing POMs into MOFs to
construct POMs-based MOFs, which provides an insight on
designing efficient and highly robust catalyst for transforming
2
CO to fine chemicals.
(Table S5, Entry 3), indicating that the Cu(I) in V-Cu-MOF is the
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J. Name., 2013, 00, 1-3 | 5
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ARTICLE
Journal Name
Non-hydrogen atoms were refined with anisotropic
displacement parameters during the final cycles. All hydrogen
Experimental
Materials and instrumentation
View Article Online
DOI: 10.1039/D0GC02812F
atoms of the organic molecule were placed based on
geometrical considerations and were included in the structure
factor calculation. CCDC 2022351 contains the crystallographic
data for V-Cu-MOF. Crystal data and structure refinement are
summarized in Table S1.
All of the reagents and solvents are of analytical grade,
purchased from commercial sources and used without further
purification. The ligand bib and the substrates propargylic
alcohols were bought from Jilin Province Extension Technology
Co., Ltd. Elemental analyses (C, H and N) were performed on a
PerkinElmer 2400 CHN elemental analyzer. V and Cu were
analyzed using a PLASMA-SPEC(I) ICP atomic emission
spectrometer. The Fourier transform infrared (FTIR) spectra
were collected on an Agilent Technologies Cary 630FTIR
Cyclization of Propargylic alcohols with CO
In a typical reaction, pr pargylic alcohol (1.0 mmol), mesitylene
internal standard, 1.0 mmol), DBU (0.2 mmol), catalyst (0.025
2
o
(
mmol), and ACN (1.0 mL) were added to a 10 mL autoclave
reactor with an internal Teflon insert. Then, the reactor was
charged with 0.4 MPa CO , and the mixture was stirred for 10
2
hours at 25 °C. At the end of reaction, the catalyst was
centrifuged and a small aliquot of the supernatant was taken
and diluted with ACN to be analyzed by gas chromatography
-
1
spectrophotometer
Thermogravimetric analysis (TGA) was conducted under a
in
the
range
400-4000 cm .
-1
nitrogen atmosphere with a heating rate of 10 °C min on an
SDT 2960 Simultaneous DSC-TGA TA Instruments up to 600 °C
Powder X-ray diffraction (PXRD) measurements were
performed on a SmartLab instrument with Cu Kα (λ = 1.5418 Å)
radiation and X-ray 40 kV/ 30 mA over the angular range 2θ 5°-
.
(GC) to calculate the yield of α-alkylidene cyclic carbonate. The
resulting organic phase was collected and purified by column
chromatography silica gel (petroleum ether / ethyl acetate) to
afford the target product.
-1
50°
at a scan rate of 10
measurements was taken by ASAP 2020 V4.00 instrument at
7K. X-ray photoelectron spectra (XPS) were collected using a
° min . Nitrogen adsorption/desorption
Recycling experiment of V-Cu-MOF
7
The reusability of the catalyst V-Cu-MOF was tested using 2-
methyl-3-butyn-2-ol (1a) as the substrate. After the completion
of the first catalytic reaction, the catalyst was recovered by
centrifugation and then washed three times with ACN. The
recovered V-Cu-MOF was dried under air and reused for the
next run under the same conditions.
Thermo ESCALAB 250 X-ray photoelectron spectrometer. The
yields of α-alkylidene cyclic carbonates were confirmed by gas
chromatography (GC) using a Shimadzu GC-2014 instrument
equipped with an SH-Rtx-Wax column. The α-alkylidene cyclic
carbonates were identified by H NMR spectra and the H NMR
spectra were recorded using a Bruker Avance 500 ( H: 500 MHz)
1
1
1
system at ambient temperature. Data are reported as chemical
1
shifts in ppm relative to TMS (0.00 ppm) for H. The following
Conflicts of interest
The authors declare no competing financial interest.
abbreviations are used to explain the multiplicities: s = singlet,
br s = broad singlet, d = doublet, t = triplet, q = quartet, and m =
multiplet.
Synthesis of V-Cu-MOF
Acknowledgements
NaVO
3 2 4 2
(21 mg, 0.17 mmol) and N H ·H O (80%, 3.1 μL, 0.05
mmol) were added into 9.50 mL of H
(
0
2
O. Then a solution of bib The authors thank the National Natural Science Foundation of
21 mg, 0.1 mmol) in DMF (0.5 mL) and Cu(NO ·3H
O (121 mg, China (Grant nos. 21872021 and 21671033).
.5 mmol) were consecutively added into above mixture and
3
)
2
2
the resulting mixture was stirred for 1 hour at room
temperature. The pH value of the mixture was adjusted with 1M
References
HCl to 4.46. Then the mixture was placed in a 23 mL Teflon 1 M. R. Allen, D. J. Frame, C. Huntingford, C. D. Jones, J. A. Lowe, M.
reactor and kept under autogenous pressure at 130 °C for 3 days.
Then the mixture was cooled to room temperature at a rate of
Meinshausen and N. Meinshausen, Nature, 2009, 458, 1163-
1166.
2
3
4
M. Li, S. Abdolmohammadi, M. S. Hoseininezhad-Namin, F.
Behmagham and E. Vessally, J CO2 Util, 2020, 38, 220-231.
M. Aresta, A. Dibenedetto and A. Angelini, Chem Rev, 2014, 114,
1
1
C
0 °C per hour, and yellow strip crystals were obtained (yield:
01 mg, 85% based on Cu). Elemental analysis for
48
H
40
N
16
O
12
V
4
Cu
4
: C, 38.67%; H, 2.70%; N, 15.03%; V, 13.67%;
1
709-1742.
Cu, 17.05%; found: C, 38.58%; H, 2.64%; N, 14.94%; V, 13.59%;
Cu, 16.93%; FTIR (cm , Fig. S3): 1534(s), 1489(m), 1441(w),
J. Graciani, K. Mudiyanselage, F. Xu, A. E. Baber, J. Evans, S. D.
Senanayake, D. J. Stacchiola, P. Liu, J. Hrbek, J. F. Sanz and J. A.
Rodriguez, Science, 2014, 345, 546.
-1
1
9
356(m), 1323(m), 1308(m), 1276(m), 1240(m), 1072(m), 935(s),
09(s), 838(m), 758(s), 657(m), 557(w), 533(s).
5
X. Sun, L. Lu, Q. Zhu, C. Wu, D. Yang, C. Chen and B. Han, Angew
Chem Int Ed, 2018, 57, 2427-2431.
Crystallography
Single-crystal X-ray diffraction (SXRD) data of V-Cu-MOF were 6 T. Sakakura, J.-C. Choi and H. Yasuda, Chem Rev, 2007, 107, 2365-
collected on a Bruker diffractometer using Mo Kα radiation (λ =
2387.
0
.71073 Å) at 293 K. The empirical absorption correction was 7 R. Babu, A. C. Kathalikkattil, R. Roshan, J. Tharun, D.-W. Kim and
D.-W. Park, Green Chem, 2016, 18, 232-242.
based on equivalent reflections. The structure was solved by
direct methods and refined by full-matrix least-squares fitting
8
W. Zhou, K. Cheng, J. Kang, C. Zhou, V. Subramanian, Q. Zhang and
Y. Wang, Chem Soc Rev, 2019, 48, 3193-3228.
2
on F using the SHELXTL crystallographic software package.
6
| J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Page 7 of 8
Please Gd roe en no Ct ha ed mj u iss tt r my argins
Journal Name
ARTICLE
9
1
1
1
1
1
1
1
1
1
1
2
2
Q. Huang, J. Liu, L. Feng, Q. Wang, W. Guan, L.-Z. Dong, L. Zhang, 40 Y. Wu, Y. Zhao, R. Li, B. Yu, Y. Chen, X. Liu, C. Wu, X.VLiuewoAarnticdleZO.nLliinue,
L.-K. Yan, Y.-Q. Lan and H.-C. Zhou, Natl Sci Rev, 2019, 7, 53-63. ACS Catal, 2017, 7, 6251-6255.
0 L.-Z. Dong, L. Zhang, J. Liu, Q. Huang, M. Lu, W.-X. Ji and Y.-Q. Lan, 41 Y. Hu, J. Song, C. Xie, H. Wu, T. Jiang, G. Yang and B. Han, ACS
Angew Chem Int Ed, 2020, 59, 2659-2663. Sustainable Chem Eng, 2019, 7, 5614-5619.
1 B. Yu, Z.-F. Diao, C.-X. Guo, C.-L. Zhong, L.-N. He, Y.-N. Zhao, Q.-W. 42 R. A. Molla, K. Ghosh, B. Banerjee, M. A. Iqubal, S. K. Kundu, S. M.
Song, A.-H. Liu and J.-Q. Wang, Green Chem, 2013, 15, 2401-2407. Islam and A. Bhaumik, J Colloid Interface Sci, 2016, 477, 220-229.
2 X.-H. Liu, J.-G. Ma, Z. Niu, G.-M. Yang and P. Cheng, Angew Chem 43 Z. Yang, B. Yu, H. Zhang, Y. Zhao, Y. Chen, Z. Ma, G. Ji, X. Gao, B.
Int Ed, 2015, 54, 988-991. Han and Z. Liu, ACS Catal, 2016, 6, 1268-1273.
3 G. Xiong, B. Yu, J. Dong, Y. Shi, B. Zhao and L.-N. He, Chem 44 Z. Zhang, H. Gao, H. Wu, Y. Qian, L. Chen and J. Chen, ACS Appl
Commun, 2017, 53, 6013-6016. Nano Mater, 2018, 1, 6463-6476.
4 Z. Zhou, C. He, J. Xiu, L. Yang and C. Duan, J Am Chem Soc, 2015, 45 C. Du, X. Lan, G. An, Q. Li and G. Bai, ACS Sustainable Chem Eng,
37, 15066-15069. 2020, 10.1021/acssuschemeng.0c00771.
5 H. Xu, X.-F. Liu, C.-S. Cao, B. Zhao, P. Cheng and L.-N. He, Adv Sci, 46 Z. Zhou, C. He, L. Yang, Y. Wang, T. Liu and C. Duan, ACS Catal,
016, 3, 1600048. 2017, 7, 2248-2256.
6 R. R. Shaikh, S. Pornpraprom and V. D’Elia, ACS Catal, 2018, 8, 419- 47 G. Zhang, H. Yang and H. Fei, ACS Catal, 2018, 8, 2519-2525.
DOI: 10.1039/D0GC02812F
1
2
4
50.
48 S.-L. Hou, J. Dong, X.-L. Jiang, Z.-H. Jiao and B. Zhao, Angew Chem
Int Ed, 2019, 58, 577-581.
7 Y. Zhou, W. Zhang, L. Ma, Y. Zhou and J. Wang, ACS Sustainable
Chem Eng, 2019, 7, 9387-9398.
8 Y. Yuan, Y. Xie, C. Zeng, D. Song, S. Chaemchuen, C. Chen and F.
Verpoort, Catal Sci Technol, 2017, 7, 2935-2939.
9 X. Yu, Z. Yang, F. Zhang, Z. Liu, P. Yang, H. Zhang, B. Yu, Y. Zhao
and Z. Liu, Chem Commun, 2019, 55, 12475-12478.
0 H. Zhou, H. Zhang, S. Mu, W.-Z. Zhang, W.-M. Ren and X.-B. Lu,
Green Chem, 2019, 21, 6335-6341.
49 Z. Wu, X. Lan, Y. Zhang, M. Li and G. Bai, Dalton Trans, 2019, 48,
11063-11069.
50 H. Furukawa, K. E. Cordova, M. O’Keeffe and O. M. Yaghi, Science,
2013, 341, 1230444.
51 M. H. Beyzavi, N. A. Vermeulen, A. J. Howarth, S. Tussupbayev, A.
B. League, N. M. Schweitzer, J. R. Gallagher, A. E. Platero-Prats, N.
Hafezi, A. A. Sarjeant, J. T. Miller, K. W. Chapman, J. F. Stoddart,
C. J. Cramer, J. T. Hupp and O. K. Farha, J Am Chem Soc, 2015, 137,
13624-13631.
1 C. Du, X. Lan, G. An, Q. Li and G. Bai, ACS Sustainable Chem Eng,
2020, 8, 7051-7058.
2
2
2 H. Zhang, H.-B. Liu and J.-M. Yue, Chem Rev, 2014, 114, 883-898.
3 X.-B. Ding, D. P. Furkert and M. A. Brimble, Org Lett, 2017, 19,
52 J. Liu, L. Chen, H. Cui, J. Zhang, L. Zhang and C.-Y. Su, Chem Soc
Rev, 2014, 43, 6011-6061.
5
418-5421.
53 R. DasandC. M. Nagaraja, Inorg Chem, 2020, 59, 9765-9773.
2
2
2
2
2
2
3
3
4 Q. Liu, L. Wu, R. Jackstell and M. Beller, Nat Commun, 2015, 6, 54 C.-Y. Sun, S.-X. Liu, D.-D. Liang, K.-Z. Shao, Y.-H. Ren and Z.-M. Su,
933. J Am Chem Soc, 2009, 131, 1883-1888.
5 H.-F. Jiang, A.-Z. Wang, H.-L. Liu and C.-R. Qi, Eur J Org Chem, 55 H.-R. Tian, Y.-W. Liu, Z. Zhang, S.-M. Liu, T.-Y. Dang, X.-H. Li, X.-W.
008, 2008, 2309-2312. Sun, Y. Lu and S.-X. Liu, Green Chem, 2020, 22, 248-255.
6 J. Hu, J. Ma, Q. Zhu, Q. Qian, H. Han, Q. Mei and B. Han, Green 56 J. Song, Z. Luo, D. K. Britt, H. Furukawa, O. M. Yaghi, K. I.
Chem, 2016, 18, 382-385. Hardcastle and C. L. Hill, J Am Chem Soc, 2011, 133, 16839-16846.
7 Y. Zhao, J. Qiu, L. Tian, Z. Li, M. Fan and J. Wang, ACS Sustainable 57 Q. Han, C. He, M. Zhao, B. Qi, J. Niu and C. Duan, J Am Chem Soc,
Chem Eng, 2016, 4, 5553-5560. 2013, 135, 10186-10189.
8 Y. Yuan, Y. Xie, C. Zeng, D. Song, S. Chaemchuen, C. Chen and F. 58 J.-S. Qin, D.-Y. Du, W. Guan, X.-J. Bo, Y.-F. Li, L.-P. Guo, Z.-M. Su,
5
2
Verpoort, Green Chem, 2017, 19, 2936-2940.
9 S. Dabral, B. Bayarmagnai, M. Hermsen, J. Schießl, V. Mormul, A.
S. K. Hashmi and T. Schaub, Org Lett, 2019, 21, 1422-1425.
Y.-Y. Wang, Y.-Q. Lan and H.-C. Zhou, J Am Chem Soc, 2015, 137,
7169-7177.
59 I. Brown, J Appl Cryst, 1996, 29, 479-480.
0 N. Kindermann, T. Jose and A. W. Kleij, Top. Curr. Chem., 2017, 60 J.-K. Li, J. Dong, C.-P. Wei, S. Yang, Y.-N. Chi, Y.-Q. Xu and C.-W. Hu,
75, 15. Inorg Chem, 2017, 56, 5748-5756.
1 B. Grignard, C. Ngassamtounzoua, S. Gennen, B. Gilbert, R. 61 H. Jia, Q. Li, A. Bayaguud, Y. Huang, S. She, K. Chen and Y. Wei,
3
Méreau, C. Jerome, T. Tassaing and C. Detrembleur,
ChemCatChem, 2018, 10, 2584-2592.
2 R. Méreau, B. Grignard, A. Boyaval, C. Detrembleur, C. Jerome and
T. Tassaing, ChemCatChem, 2018, 10, 956-960.
Dalton Trans, 2018, 47, 577-584.
62 W. Yang, H.-Y. Wu, R.-X. Wang, Q.-J. Pan, Z.-M. Sun and H. Zhang,
Inorg Chem, 2012, 51, 11458-11465.
3
63 C. Qi, H. Jiang, L. Huang, G. Yuan and Y. Ren, Org Lett, 2011, 13,
3
3 Y. Kayaki, M. Yamamoto and T. Ikariya, J Org Chem, 2007, 72, 647-
5520-5523.
649.
64 Q.-W. Song, B. Yu, X.-D. Li, R. Ma, Z.-F. Diao, R.-G. Li, W. Li and L.-
N. He, Green Chem, 2014, 16, 1633-1638.
3
3
4 Y.-L. Sun, Y. Wei and M. Shi, Org Chem Front, 2019, 6, 2420-2429.
5 I. Yoshio, I. Jiro, T. Masaaki and H. Harukichi, Bull Chem Soc Jpn, 65 Z.-H. Zhou, X. Zhang, Y.-F. Huang, K.-H. Chen and L.-N. He, Chin J
987, 60, 1204-1206. Catal, 2019, 40, 1345-1351.
6 Q.-W. Song, W.-Q. Chen, R. Ma, A. Yu, Q.-Y. Li, Y. Chang and L.-N. 66 H. Nakano, T. Ozeki and A. Yagasaki, Acta Cryst, 2002, 58, m464-
He, ChemSusChem, 2015, 8, 821-827. m465.
7 S. Sun, B. Wang, N. Gu, J.-T. Yu and J. Cheng, Org Lett, 2017, 19, 67 V. K. Tiwari, B. B. Mishra, K. B. Mishra, N. Mishra, A. S. Singh and
088-1091. X. Chen, Chem Rev, 2016, 116, 3086-3240.
8 Y. Zhao, Z. Yang, B. Yu, H. Zhang, H. Xu, L. Hao, B. Han and Z. Liu, 68 L. Ouyang, X. Tang, H. He, C. Qi, W. Xiong, Y. Ren and H. Jiang, Adv
1
3
3
3
3
1
Chem Sci, 2015, 6, 2297-2301.
Synth Catal, 2015, 357, 2556-2565.
9 J. Qiu, Y. Zhao, Z. Li, H. Wang, M. Fan and J. Wang, ChemSusChem,
2017, 10, 1120-1127.
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Green Chemistry
Page 8 of 8
View Article Online
DOI: 10.1039/D0GC02812F
Table of Contents
A novel polyoxovanadate-based Cu(I)–organic framework (V-Cu-MOF) was
synthesized and utilized as a heterogeneous catalyst for the cyclization of CO with
2
propargylic alcohols to obtain high value-added α-alkylidene cyclic carbonates,
performing high catalytic activity and sustainability.