New lanthanide(iii) coordination polymers: Synthesis, structural features, and catalytic activity in CO2 fixation

Article abstract of DOI:10.1039/c7dt03574h

A new series of lanthanide coordination polymers formulated as [Ln(μ-L)(μ₃-L)(H₂O)]_nX_n (Ln/X = Er/Cl (1), Er/Br (2), Tm/Cl (3), Tm/Br (4), Yb/Cl (5), and Yb/Br (6); L = 1,3-bis(4-carboxyphenyl) imidazolium carboxylate(1+)) were solvothermally generated and fully characterized. Single-crystal X-ray diffraction analysis shows that all products possess isomorphous structures that are composed of cationic 1D double chains with encapsulated halide anions. From a topological perspective, such 1D chains can be classified as a binodal 3,5-connected net with a unique topology defined by the point symbol of (3·4²)(3²·4²·5³·6²·7). All products 1-6 feature a remarkable thermal stability and were applied as highly active heterogeneous catalysts for the coupling reactions between halogenated propylene oxides and CO₂ to give the corresponding cyclic carbonates. The reaction conditions, substrate and catalyst scope, and mechanistic features of this catalytic transformation were investigated. High products yields (up to 98%), elevated TONs (up to 3920) or TOFs (up to 326 h^-1) were attained under mild reaction conditions. In addition, catalyst 6 can be recycled at least eight times with no loss of catalytic activity.

Full text of DOI:10.1039/c7dt03574h

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New Lanthanide (III) Coordination Polymers: Synthesis, Structural
Features, and Catalytic Activity in CO Fixation
2
Received 00th January 20xx,
Accepted 00th January 20xx
a
a
a
b
a
a
c
Cong Xu , Yan Liu , Li Wang , Jingxin Ma , Lizi Yang , Fu-xin Pan , Alexander M. Kirillov and
a,*
Weisheng Liu
DOI: 10.1039/x0xx00000x
A new series of lanthanide coordination polymers formulated as [Ln(µ-L)(µ
3 2 n n
-L)(H O)] X (Ln/X = Er/Cl (1), Er/Br (2), Tm/Cl
www.rsc.org/
(3), Tm/Br (4), Yb/Cl (5), and Yb/Br (6); L = 1,3-bis(4-carboxyphenyl) imidazolium carboxylate(1+)) was solvothermally
generated and fully characterized. Single-crystal X-ray diffraction analysis shows that all products possess isomorphous
structures that are composed of cationic 1D double chains with encapsulated halide anions. From a topological
perspective, such 1D chains can be classified as a binodal 3,5-connected net with a unique topology defined by the point
2
2
2
3
2
symbol of (3.4 )(3 .4 .5 .6 .7). All products 1-6 feature a remarkable thermal stability and were applied as highly active
heterogeneous catalysts for the coupling reactions between halogenated propylene oxides and CO to give the
2
corresponding cyclic carbonates. Reaction conditions, substrate and catalyst scope, and mechanistic features for this
catalytic transformation were investigated. High products yields (up to 98%), elevated TONs (up to 3920) or TOFs (up to
-1
3
26 h ) were attained under mild reaction conditions. In addition, the catalyst 6 can be recycled at least eight times with
no loss of catalytic activity.
compounds are common catalysts for the conversion of carbon
dioxide into cyclic carbonates is very effective strategy in the
INTRODUCTION
2
5-28
past studies.
Compared with transition metal based
Lanthanide coordination polymers (Ln-CPs) have emerged as
an important class of compounds with various functional
catalysts, the lanthanide containing compounds can potentially
3
+
1
,
have some advantages, because Ln ions can not only act as
possible Lewis acidic sites and enhance catalytic activity, but
also can show some intrinsic characteristics and rich
properties and applications, ranging from in chemical sensing,
2
3, 4 5-8
luminescence properties, gas storage and separation and
9
-17
heterogeneous catalysis.
Among these, heterogeneous
2
9-32
coordination patterns.
heterogeneous catalysts for coupling of CO
obtain cyclic carbonates can be considered as an interesting
and good candidate for CO fixation.
In addition, the application of CPs as
catalysis has attracted more attention because of the unique f-
1
f electron transition of lanthanide ions.
8-20
2
and epoxides to
As an inexpensive, nontoxic, and abundant renewable C1
2
source, CO could be considered as an available pollutant
2
Until now, only a few CP or MOF catalysts have been
resources used in organic synthesis aspect and the catalytic
reported for such a type of transformation, without showing a
31, 33-35
conversion of CO into useful products became a hot issue in
2
2
scientific research and environmental governance. In this
1
high efficiency in CO
2
conversion.
Hence, the Ln CPs with
stable metal-organic structures can be considered as good
area, one of the most interesting directions of CO conversion
2
35-41
candidates for the CO
Based on the above background, we report herein a series
2-24 of Ln CPs formulated as [Ln(µ-L)(µ -L)(H O)] (Ln/X = Er/Cl
), Yb/Cl ( ), and Yb/Br ( ); L =
imidazolium carboxylate(1+)).
2
fixation reactions.
is the coupling reaction of CO and epoxides to form cyclic
2
carbonates, which is atomic-economic and having industrial
2
3
2
n n
X
value in important industrial intermediates synthesis.
(
1), Er/Br (
2
), Tm/Cl (
3
), Tm/Br (
4
5
6
Using transition metal salts and related coordination
1,3-bis(4-carboxyphenyl)
Solvothermal synthesis, full characterization, structural and
topological features, thermal stability, and catalytic properties
of these products will be discussed in the present work.
EXPERIMENTAL SECTION
All the materials were purchased from commercial sources and
used
without
further
purification.
1,3-Bis(4-
+
carboxyphenyl)imidazolium chloride (H L Cl ) and 1,3-bis(4-
-
2
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+
-
carboxyphenyl)imidazolium
bromide
(H
2, 43
2
L Br )
were The synthesis of
TmCl ·6H O (0.0116 g, 0.025 mmol) as a starting material.
The single-crystal X-ray diffraction data were collected on a Compound was obtained in 71% yield based on Tm(III). IR
Bruker SMART 1000 CCD diffractometer operating at 48 kV and (KBr pellet, cm ): 505 (m), 543 (m), 692 (m), 781 (vs), 858 (m),
0 mA by using a graphite-monochromated Mo-Kα radiation 1130 (m), 1253 (m), 1337 (vs), 1383 (s), 1552 (vs), 1616 (vs),
3 was similar to that of 1 except using
4
synthesized following a literature protocol.
3
2
3
-1
3
source (λ = 0.71073 Å). An empirical absorption correction 2924 (w), 3118 (w), 3435 (m). Elemental analysis: N 6.50%, C
based on a comparison of redundant and equivalent 48.63%, H 2.84%. (Calculated: N 6.69%, C 48.79%, H 2.89%).
reflections was applied by using SADABS. All structures were
4
4
3 2 n n
Preparation of [Tm(µ-L)(µ -L)(H O)] Br (4).
solved by direct methods using SHELXTL-2013 and refined by
2
45
full-matrix least-squares cycles on F via Olex2 program . All The synthesis of
the non-hydrogen atoms were refined anisotropically. (0.0102 g, 0.025 mmol) and H
Topological analysis of metal-organic networks in the starting materials. Compound
obtained compounds was performed using Topos software based on Tm(III). IR (KBr pellet, cm ): 509 (w), 547 (w), 692
4
was similar to that of
1
except using TmBr
L Br (0.0195 g, 0.05 mmol) as
was obtained in 70% yield
3
+
-
2
4
-1
4
6, 47
and applying a concept of a simplified underlying net.
underlying net can be generated by reducing the µ -L and µ-L 1545 (vs), 1616 (vs), 2898 (w), 2950 (w), 3429 (w). Elemental
moieties to their centroids and eliminating terminal H analysis: N 6.18%, C 46.43%, H 2.69%. (Calculated: N 6.36%, C
ligands. Connectivity of Er nodes via coordination bonds with 46.33%, H 2.74%).
An (w), 783 (s), 858 (m), 1134 (w), 1257 (m), 1338 (s), 1406 (vs),
3
2
O
µ
3
-L and µ-L blocks was maintained.
Preparation of [Yb(µ-L)(µ
was similar to that of
O (0.0097 g, 0.025 mmol) as a starting material.
luminescence spectra and lifetime measurements were Compound was obtained in 68% yield based on Yb(III). IR
3 2 n n
-L)(H O)] Cl (5).
X-ray powder diffraction data were collected on a
PANalytical X'Pert Pro Diffractometer operated at 40 kV and 40 The synthesis of
mA with Cu Kα radiation (λ=1.5406Å). The steady-state YbCl ·6H
5
1 except using
3
2
5
-1
measured on an Edinburgh Instruments FSL920 fluorescence (KBr pellet, cm ): 511 (w), 547 (w), 697 (w), 781 (s), 860 (m),
spectrometer, with 450 W Xe arc lamp as the steady-state 1134 (w), 1255 (m), 1338 (s), 1406 (vs), 1548 (vs), 1616 (vs),
excitation source or Nd-pumped OPOlette laser as the 2927 (w), 3423 (w). Elemental analysis: N 6.42%, C 48.46%, H
excitation source for lifetime measurements. The quantum 2.84%. (Calculated: N 6.66%, C 48.55%, H 2.88%).
yields of the compounds in the solid state were determined
Preparation of [Yb(µ-L)(µ
coating) from The synthesis of was similar to that of
Edinburgh Instruments FLS920. The infrared spectra were YbBr ·6H O (0.0130 g, 0.025 mmol) and H
recorded on a Burker VERTEX 70 FTIR spectrometer using the mmol) as starting materials. Compound
3 2 n n
-L)(H O)] Br (6).
according to an absolute method of Wrighton using an
integrating sphere (150 mm diameter, BaSO
4
6
1
except using
L Br (0.0195 g, 0.05
was obtained in 65%
+
-
3
2
2
6
−
1
-1
KBr pellets in the 400–4000 cm region.
yield based on Yb(III). IR (KBr pellet, cm ): 509 (w), 545 (w),
94 (m), 781 (s), 860 (m), 1130 (w), 1182 (w), 1257 (m), 1338
s), 1410 (vs), 1545 (vs), 1618 (vs), 2920 (w), 3410 (w).
O (0.0095 g, 0.025 Elemental analysis: N 6.10%, C 46.09%, H 2.68%. (Calculated: N
L Cl (0.0172g, 0.05 mmol), N,N-dimethylacetamide 6.30%, C 45.91%, H 2.72%).
DMA, 2 mL) and distilled water (1 mL). After ultrasonic
oscillation for 5 minutes, the mixture was heated at 85 °C for
4 h and then cooled to room temperature, resulting in the The cycloaddition reactions under high temperature and
6
Preparation of [Er(µ-L)(µ
3 2 n n
-L)(H O)] Cl (1).
(
A 20 mL vial was charged with ErCl3`6H
2
+
-
mmol), H
2
(
Catalytic studies.
2
formation of light pink block crystals. These were filtered off, pressure were carried out in 22 ml stainless steel reactor
washed with ethanol, and dried at room temperature to give equipped with a magnetic stirrer. In these experiments,
-1
compound
24 (m), 622 (m), 694 (m), 781 (s), 858 (w), 1134 (m), 1253 (0.01mmol) and Tetrabutylammonium bromide ([Bu
m), 1336 (s), 1383 (s), 1550 (vs), 1618 (vs), 2930 (w), 3118 (w), 24.2mg, 0.075mmol) were added into the reactor, charged
481 (m). Elemental analysis: N 6.65%, C 49.05%, H 3.00%. with 10bar CO . After sealing, the reactor was put into a 120
Calculated: N 6.71%, C 48.89%, H 2.90%). oil bath, reacted at 3 h. After the reaction finished, the reactor
was put out of oil, cool to room temperature and the CO was
1
in 76% yield based on Er(III). IR (KBr pellet, cm ): propylene oxide derivatives (10mmol), Compound 1-6
5
4
N]Br,
(
3
2
℃
(
2
Preparation of [Er(µ-L)(µ
The synthesis of was similar to that of
0.0102 g, 0.025 mmol) and H
starting materials. Compound
based on Er(III). IR (KBr pellet, cm ): 522 (m), 622 (m), 781 (s), Propylene oxide derivatives (10mmol), Compound 1-6
58 (m), 1255 (m), 1338 (m), 1385 (s), 1547 (s), 1618 (s), 2930 (0.0025mmol) and [Bu N]Br (96.8mg, 0.3mmol) were then
w), 3444 (m). Elemental analysis: N 6.22%, C 46.55%, H 2.70%. added into the bottle. We use a rubber plug to seal the bottle
Calculated: N 6.37%, C 46.42%, H 2.75%). and plunge a needle which is connected with a CO ballon.
3 2 n n
-L)(H O)] Br (2).
released slowly. The product was moved to a 2ml centrifugal
tube and separates the catalyst solids via centrifugation.
The cycloaddition reactions under mild conditions were
2
1
except using ErBr
3
+
-
(
2
L Br (0.0195 g, 0.05 mmol) as
2
was obtained in 67% yield conducted in 5ml round bottle with a small magnetic stirrer.
1
-
8
4
(
(
2
After each 3h, the ballon should be recharged with CO2. The
reaction was put into oil bath at desired temperature and
3 2 n n
Preparation of [Tm(µ-L)(µ -L)(H O)] Cl (3).
2
| J. Name., 2012, 00, 1-3
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Ple Da sae l tdo onn To rt aa nd sj ua sct t mi o an r sg ins
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DOI: 10.1039/C7DT03574H
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ARTICLE
reacted for a certain time. After finished, the round bottle was group
P-1 (Table S3, ESI). Herein, the structure of 1 will be
put out of the oil, separate the catalyst solids via discussed in detail as a representative example.
1
centrifugation. The yield of product was calculated by using H
NMR analysis.
As shown in Figure 1, the Er1 centers are seven-coordinate
and have distorted pentagonal bipyramid [ErO
environment, which is filled by two distinct µ-L and µ -L
O ligand. There are also
a
7
]
3
moieties, as well as one terminal H
two unbound chloride
2
Figure 2. Two typical coordination modes of the ligand L observed in compounds 1.
+
anions per each cationic [Er (µ-L) (µ -L) (H O) ] unit. Each Er1
2
2
3
2
2
2
center is connected to five carboxylate groups coming from
three µ -L and two µ-L blocks (Figure 2, mode B and A,
3
respectively). The adjacent Er1 atoms are doubly
interconnected by two carboxylate groups from two µ -L
3
moieties, forming a dimeric Er motifs with a shortest Er…Er
2
separation of 5.204 Å (Figure 1b,c). These motifs are then
Figure 1. Structural fragments of
1. a) Coordination environment of two adjacent
Eu1 centers. b) 1D double chain structure. c) Er
2
unit and coordination polyhedra further held together via remaining carboxylate groups of µ -L
3
around Er centers. d) Packing diagram along thea axis showing three adjacent 1D
double chains. e) Topological representation of an underlying 1D chain showing a
topologically unique binodal 3,5-connected net; rotated view along the b axis; Er
and µ-L to generate an intricate 1D double chain (Figure
).From a topological perspective (Figure 1e), an underlying
1
metal-organic chain is composed of the 5-connected Er1
3
nodes (pink balls), centroids of µ-L and µ -L moieties (gray).
nodes, 3-connected µ -L nodes, and 2-connected µ-L linkers.
3
This chain can be classified as a binodal 3,5-connected net with
the unique topology, which is defined by the point symbol of
Catalyst recycling tests.
In recycling experiments, catalyst
6
was used in a five-fold
2
2
2
3
2
2
2
2
3
2
3.4 )(3 .4 .5 .6 .7). Herein, the (3.4 ) and (3 .4 .5 .6 .7)
(
amount (X mol%) in comparison with standard tests, along
with 50 mmol epichlorohydrin substrate and 3 mol% of
notations correspond to the µ -L and Er1 nodes, respectively.
3
The topology of 1D double chains in
1 well contrasts with the
[Bu N]Br co-catalyst. The reaction was performed at 70 ℃
4
kgd topological 2D layers identified in related coordination
+ 47
using 1 atm CO and 12 h reaction time. After the reaction,
2
1
reaction mixture was analyzed by H NMR and a solid catalyst
polymers derived from [H L] . In
1, the chloride anions are
2
located in the pores of the structure (Figure 1d) and could be
-
was separated by centrifugation, washed with CH Cl for 3
2
-
2
divided into two parts, the connector Cl (Cl1) and the inner Cl
Cl2). There are some weak interactions between Cl1 and an
times and dried at 70
℃ for 6 h. A subsequent reaction was
(
then continued with the precise mass of rest catalyst and same
quantity of epichlorohydrin which could keep the same ratio of
catalyst and substrate.
imidazolate H10 atom, as well as Cl2 and an imidazolate H27
atom (Figure S1, ESI).
Thermogravimetric Analysis
The stability of compounds
1
–
6
was examined by
RESULTS AND DISCUSSION
thermogravimetric analysis (TGA) in air atmosphere in the
temperature range of 20−800 °C. The obtained results (Figure
S2, ESI) indicate that all compounds show a similar thermal
behavior owing to their isomorphous structures. Thus, only the
Structural Features
The X-ray single crystal analysis reveals that all compounds 1-6
are isomorphous and crystalize in a triclinic system, space
thermal stability of
1 is discussed in detail. TGA of 1 displays a
loss of one coordination and one crystallization water
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molecules on heating up to 140 °C with the observed weight active with the product yields ranging from 76% for
loss of 4.2% (calculated weight loss is 4.3%). After removal of active, entry 9) to 98% for (the most active entry 14).
water, a dehydrated sample apparently remains stable up to According to table 1, we can see that the activity of chlorine
50 °C. Above this temperature, the decomposition of metal- compound and are not higher than bromine compound
organic network occurs. These data indicate that the metal- 2,4 and . This may be because of the bromine anions could
organic compounds derived from an imidazolium-based the increases rigidity of the structure and the channel of 2,4
1 (the least
6
4
1,
3
5
6
+
48, 49
aromatic carboxylate [H
stability.
2
L] blocks have an excellent thermal and
6 may be easier to attract halogenated groups.
Furthermore,
several
typical
epoxide
substrates
(epibromohydrin, allyl glycidyl ether, epoxy styrene, phenyl
glycidyl ether, propylene
a
Table 1. Synthesis of cyclic carbonates catalysed by Ln CPs 1-6 at different conditions.
O
0.025mol% Cat.
O
O
Cl
O
1atm CO2,Solvent free
Cl
b,c
T
ꢀ
ꢁꢂ
ꢃ
Time
(h)
3
Co-cat.
Yield.
(%)
92
97
93
98
93
98
---
TOF
Figure 3. a) Recycling of catalyst
and CO under optimized reaction conditions: catalyst (0.025 mol%), CO
[Bu N]Br (3 mol%) 12h. b) PXRD pattern of before and after being
6
in the coupling reaction of epichlorohydrin
Entry
Cat.
-1 d
(
℃)
(bar)
10
10
10
10
10
10
10
10
1
(mol%)
(h )
2
2
(1 atm),
e
7
0
℃
,
4
6
1
1
2
3
4
5
6
6
---
1
2
3
4
5
6
6
6
6
6
6
6
6
6
6
6
6
6
6
---
120
120
120
120
120
120
120
120
70
0.75
0.75
0.75
0.75
0.75
0.75
---
0.75
3
307
323
310
327
310
327
---
e
recycled for 8 times.
2
3
e
3
3
e
4
3
Luminescent Studies
e
5
3
The transient and steady-state photoluminescence spectra of
e
6
3
compound 1-6 were collected on the crystalline samples at
e
7
3
room temperature. As the result,
3
and
4
shows no obvious
8
9
3
21
76
88
78
92
85
98
40
75
46
67
80
74
66
45
60
74
83
58
---
70
peak which could be owing to Tm complex, so only 1,2 and 5,6
12
12
12
12
12
12
12
12
3
253
293
260
307
283
327
133
250
613
447
356
247
220
150
200
247
277
193
---
can be disscused above. The solid state emission spectra of Er
10
70
1
3
1
1
1
1
1
2
3
4
70
1
3
compounds
wavelength 310nm where the Yb compounds
32nm. As is shown in ESI Figure S3, both Er and Yb
1
and
2
were measured under the excitation
70
1
3
5
and were
6
70
1
3
3
70
1
3
compounds show broad bands NIR emission. During 1400-
4
4
15
30
1
3
1600nm, the band could be owing to the
I13/2→ I15/2
1
1
1
1
6
7
8
9
50
1
3
transitions and the band in the range of 900-1100nm due to
2
the
70
1
3
2
F5/2→ F7/2 transitions. According to Figure S3,
70
1
6
3
unfortunately, because of the relatively low efficient
3
70
1
9
3
+
3+
f
sensitization effect of ligand to Er and Yb ion, we failed to
get stable lifetime and quantum yield value.
20
70
1
12
12
12
12
12
12
12
12
12
3
g
21
70
1
3
2
2
2
2
2
70
1
0.1
0.5
1
Catalytic Activity for CO
In our initial tests, we selected epichlorohydrin as an epoxide
to react with CO and to explore optimum conditions for this
coupling reaction (Table 1). Initially, a mixture of catalyst (0.1
mol%; Compouns 1-6 and co-catalyst (0.75 mol%;
tetrabutylammonium bromide, [Bu N]Br) was tested in the
presence of 10 bars of CO at 120 °C and under solvent free
2
Fixation
3
70
1
4
70
1
5
h
70
1
2
2
2
6
70
1
3
2
2
7
8
70
1
---
3
)
70
1
15
50
4
a
Reaction conditions: epichlorohydrin (10 mmol), catalyst (0.025 mol%), [Bu
4
N]Br
2
b
1
c
as the co-catalyst, CO
2
balloon (1 bar). Determined by H NMR. TOF =
conditions, resulting in the formation of the corresponding
cyclic carbonate in 92-98% yields (entry 1-7). These results
reveal that such a series of CPs can efficiently catalyse the CO2
d
e
Yield/ncat/h. Selectivity for cyclic carbonate was always above 99%. Catalyst
f
g
h
(
4 4
0.1mol%). Co-catalyst [Bu N]I. Co-catalyst [Bu N]Cl. Catalyst (0.0125 mol%).
fixation, whereas a blank test performed in the absence of the oxide, epoxy cyclohexane, ethylene glycol diglycidyl ether, 1,2-
CP catalyst but in the presence of [Bu N]Br co-catalyst showed epoxyisobutane, 1,2-epoxybutane) were examined for this
4
only 21% product yield (entry 8). Further optimization of the cycloaddition reaction catalysed by
6. Under the optimized
reaction conditions was performed, allowing to achieve high reaction conditions, the epichlorohydrin, allyl glycidyl ether,
product yields (up to 98%) at a milder reaction temperature and epibromohydrin are highly reactive, while other substrates
(
70 °C), atmospheric CO pressure (1 bar), although at slightly (epoxy styrene, phenyl glycidyl ether, propylene oxide, epoxy
2
prolonged reaction time (12 h) and higher catalyst loading. cyclohexane, ethylene glycol diglycidyl ether, 1,2-
Under similar reaction conditions, all compounds
1-
6
are quite epoxyisobutane, 1,2-epoxybutane) lead to inferior yields of
4
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Ple Da sae l tdo onn To rt aa nd sj ua sct t mi o an r sg ins
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DOI: 10.1039/C7DT03574H
Journal Name
ARTICLE
cyclic carbonates that are in the range of 15%-58% (Table S2
,
Interestingly, under mild conditions, the obtained
compounds act as highly efficient heterogeneous catalysts
and a halogenated
and apply it propylene oxide, resulting in TONs up to 3920 and TOFs up to
in consecutive catalytic runs (Figure 3). The PXRD results show 326. The reaction conditions were optimized and the substrate
that after eight cycles, the framework of is essentially scope was investigated. The most active catalyst can also be
ESI).
1-6
Given a heterogeneous nature of the present catalytic for the cycloaddition reaction between CO
systems, we attempted to recycle the compound
2
6
6
6
retained, also maintaining its catalytic activity. A slight recycled for at least 8 times without any notable loss of
difference in the obtained product yields can be explained by activity, thus highlighting the application of the present type of
an accuracy of the product analysis by NMR spectroscopy. lanthanide coordination polymers in heterogeneous catalysis
Furthermore, a comparison of the catalytic performance of
6
and, in particular, for the transformations involving the fixation
with other CPs or MOFs applied for the present type of of carbon dioxide. Future research aiming at widening the
38,45,53-55,
catalytic transformations
(Table S2) reveals a number scope and optimizing further the catalytic reaction parameters
of advantages, namely higher TON or TOF values, milder will be pursued.
reaction conditions, and the use of the solvent-free system. A
possible mechanism for the cycloaddition reaction between
Acknowledgements
CO
2
and an epoxide can be suggested; it comprises several
3
+
stages. (1) Terminal water ligand in CP leaves a Ln
The authors acknowledge financial support from the National
Natural Science Foundation of China (21431002, 21701070)
and the Fundamental Research Funds for the Central
Universities (lzujbky-2015-k04).
3
coordination sphere. (2) Lewis acidic Ln site can coordinate
+
−
an oxygen atom of an epoxide. (3) The nucleophilic Br attacks
the less-hindered carbon atom to open an epoxy ring. (4) CO
2
then interacts with an oxygen anion of the opened epoxy ring,
forming an alkyl carbonate salt. (5) Finally, a cyclic carbonate
product is obtained through an intramolecular ring closure. As Notes and references
the consequence, we can get an excellent yield of the
a
Key Laboratory of Nonferrous Metals Chemistry and Resources Utilization of
Gansu Province and State Key Laboratory of Applied Organic Chemistry, College of
corresponding cyclic carbonate when using an elevated
temperature and pressure (Figure 3). Under mild conditions, a Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, P. R.
China
Email: liuws@lzu.edu.cn Tel: +86 931-8915151
possible pathway could be described as a chain cracking
pathway. First, the chain by chain structure separates partly
b
and the open halogen anion site evolves. Then, the halogen
atom of halogenated propylene oxide is easily attracted by the
College of Chemistry and Chemical Engineering, Ningxia University, Yinchuan
50021, P.R. China.
7
+
δ -π system and the oxide atom are coordinated with a water-
c
Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa,
Av. Rovisco Pais, 1049-001, Lisbon, Portugal.
3
+
−
free Ln centre. The nucleophilic Br from the [Bu
the less-hindered carbon atom to open the epoxy ring. At last,
CO inserts and an intramolecular ring closure occur. Under
mild conditions, the halogenated propylene oxide can react via structural data, characterization details, and catalytic data. See
DOI: 10.1039/b000000x/.
4
N]Br attacks
†
Electronic Supplementary Information (ESI) available:
2
Supporting Figures S1-S7 and Tables S1-S4 containing additional
both mechanistic pathways. Other epoxy substrates cannot
reach an ideal yield because of lower temperature and CO
2
1
2
3
4
5
6
7
8
9
1
L. E. Kreno, K. Leong, O. K. Farha, M. Allendorf, R. P. Van
Duyne and J. T. Hupp, Chem. Rev., 2012, 112, 1105-1125.
W. P. Lustig, S. Mukherjee, N. D. Rudd, A. V. Desai, J. Li and
S. K. Ghosh, Chem. Soc. Rev., 2017, 46, 3242-3285.
M. D. Allendorf, C. A. Bauer, R. K. Bhakta and R. J. Houk,
Chem. Soc. Rev., 2009, 38, 1330-1352.
pressure so that it cannot get the energy barrier of the
reaction.
CONCLUSIONS
In the present study, we have obtained a novel series of
lanthanide 1D double chain coordination polymers with a
Y. Cui, Y. Yue, G. Qian and B. Chen, Chem. Rev., 2012, 112
126-1162.
J. R. Li, J. Sculley and H. C. Zhou, Chem. Rev., 2012, 112, 869-
32.
J. R. Li, R. J. Kuppler and H. C. Zhou, Chem. Soc. Rev., 2009,
, 1477-1504.
L. J. Murray, M. Dinca and J. R. Long, Chem. Soc. Rev., 2009,
, 1294-1314.
T. Duren, Y. S. Bae and R. Q. Snurr, Chem. Soc. Rev., 2009,
, 1237-1247.
,
1
general formula [Ln(µ-L)(µ
3
-L)(H
2
O)]
n
X
n
[Ln/X = Er/Cl (
1), Er/Br
(
2), Tm/Cl (3), Tm/Br (4), Yb/Cl (
5), and Yb/Br (6)]. Single-
9
crystal X-ray structural analysis revealed that all compounds
are isomorphous and feature a cationic 1D metal-organic
network with encapsulated halide anions. Topological analysis
of the underlying 1D chains was performed, allowing to
identify a novel type of binodal 3,5-connected net. All
38
38
compounds 1-6 also exhibit a remarkable thermal stability,
38
with their dehydrated networks remaining stable up to 450 °C.
Hence, the present work widens a family of thermally stable
J. Lee, O. K. Farha, J. Roberts, K. A. Scheidt, S. T. Nguyen and
J. T. Hupp, Chem. Soc. Rev., 2009, 38, 1450-1459.
coordination polymers derived from an imidazolium-based
+
L] blocks.
0
A. Corma, H. Garcia and F. X. Llabres i Xamena, Chem. Rev.,
aromatic carboxylate [H
2
2
010, 110, 4606-4655.
This journal is © The Royal Society of Chemistry 20xx
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Dalton Transactions
Page 6 of 7
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ARTICLE
Journal Name
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
M. Yoon, R. Srirambalaji and K. Kim, Chem. Rev., 2012, 112
,
36 L. Liu, J. Zhang, H. Fang, L. Chen and C. Y. Su, Chem. Asian. J.,
2016, 11, 2278-2283.
1
196-1231.
J. Lee, O. K. Farha, J. Roberts, K. A. Scheidt, S. T. Nguyen and 37 X. Huang, Y. Chen, Z. Lin, X. Ren, Y. Song, Z. Xu, X. Dong, X.
J. T. Hupp, Chem. Soc. Rev., 2009, 38, 1450.
Li, C. Hu and B. Wang, Chem. Commun. (Camb), 2014, 50,
L. Zhu, X. Q. Liu, H. L. Jiang and L. B. Sun, Chem. Rev., 2017,
2624-2627.
1
17, 8129-8176.
Z. Zhou, C. He, J. Xiu, L. Yang and C. Duan, J. Am. Chem. Soc.,
015, 137, 15066-15069.
38 B. Xu, P. Wang, M. Lv, D. Yuan and Y. Yao, ChemCatChem.,
2016, , 2466-2471.
8
2
39 J. Dong, H. Xu, S. L. Hou, Z. L. Wu and B. Zhao, Inorg. Chem.,
2017, 56, 6244-6250.
H. X. Li, Z. G. Ren, Y. Zhang, W. H. Zhang, J. P. Lang and Q.
Shen, J. Am. Chem. Soc., 2005, 127, 1122-1123.
40 C. Y. Gao, J. Ai, H. R. Tian, D. Wu and Z. M. Sun, Chem.
Commun. (Camb), 2017, 53, 1293-1296.
H. X. Li, M. L. Cheng, Z. G. Ren, W. H. Zhang, J. P. Lang and Q.
Shen, Inorg. Chem., 2006, 45, 1885-1887.
41 J. Ai, X. Min, C. Y. Gao, H. R. Tian, S. Dang and Z. M. Sun,
Dalton Trans., 2017, 46, 6756-6761.
H.-X. Li, M.-L. Cheng, H.-M. Wang, X.-J. Yang, Z.-G. Ren and
J.-P. Lang, Organometallics., 2011, 30, 208-214.
42 S. Sen, N. N. Nair, T. Yamada, H. Kitagawa and P. K.
Bharadwaj, J. Am. Chem. Soc., 2012, 134, 19432-19437.
43 R. S. Crees, M. L. Cole, L. R. Hanton and C. J. Sumby, Inorg.
Chem., 2010, 49, 1712-1719.
D. Banerjee, Z. Hu and J. Li, Dalton Trans., 2014, 43, 10668-
1
0685.
Z. Hu, B. J. Deibert and J. Li, Chem. Soc. Rev., 2014, 43, 5815-
840.
5
44 G. M. Sheldrick, Acta Crystallographica Section C: Structural
Chemistry, 2015, 71, 3-8.
A. Lan, K. Li, H. Wu, D. H. Olson, T. J. Emge, W. Ki, M. Hong
and J. Li, Angewandte Chemie, 2009, 48, 2334-2338.
45 O. V. Dolomanov, L. J. Bourhis, R. J. Gildea, J. A. Howard and
J. D. Figueroa, T. Fout, S. Plasynski, H. McIlvried and R. D.
H. Puschmann, Journal of Applied Crystallography, 2009, 42,
Srivastava, INT. J. GREENH. GAS. CON., 2008,
T. Sakakura, J. C. Choi and H. Yasuda, Chem. Rev., 2007, 107
365-2387.
2
, 9-20.
339-341.
,
46 V. A. Blatov, IUCr. CompComm. Newsletter., 2006, 7, 4.
2
47 V. A. Blatov, A. P. Shevchenko and D. M. Proserpio, Crystal
Growth & Design, 2014, 14, 3576-3586.
B. Schaffner, F. Schaffner, S. P. Verevkin and A. Borner,
Chem. Rev., 2010, 110, 4554-4581.
48 C. Xu, A. M. Kirillov, Y. Shu, Y. Liu, L. Guo, L. Yang, W. Dou,
W. Liu, C. Chen, X. Huang, J. Zhang and W. Liu,
CrystEngComm., 2016, 18, 1190-1199.
K. M. Yu, C. M. Yeung and S. C. Tsang, J. Am. Chem. Soc.,
2
007, 129, 6360-6361.
X. B. Lu, W. M. Ren and G. P. Wu, Acc. Chem. Res., 2012, 45
721-1735.
M. Aresta, A. Dibenedetto and A. Angelini, Chem. Rev.,
014, 114, 1709-1742.
C. Maeda, Y. Miyazaki and T. Ema, CATAL. SCI. TECHNOL.,
014, , 1482.
Q. Liu, L. Wu, R. Jackstell and M. Beller, Nat. Commun.,
015, , 5933.
,
49 R. Custelcean, Chem. Soc. Rev., 2014, 43, 1813-1824.
1
2
2
4
2
6
G. Choppin and E. Rizkalla, Handbook on the Physics and
Chemistry of Rare Earths Vol 18; Chapter 128: Solution
chemistry of actinides and lanthanides, Elsevier Science,
Amsterdam, 1994.
3
0
L. R. Morss, N. M. Edelstein and J. Fuger, The Chemistry of
the Actinide and Transactinide Elements, Springer,
Dordrecht, 2011.
3
3
1
2
H. Xu, B. Zhai, C. S. Cao and B. Zhao, Inorg. Chem., 2016, 55
,
9
671-9676.
K. L. Nash, Handbook on the Physics and Chemistry of Rare
Earths Vol 18; Chapter 121: Separation chemistry for
lanthanides and trivalent actinides, Elsevier Science,
Amsterdam, 1994.
3
3
3
4
J. Qin, P. Wang, Q. Li, Y. Zhang, D. Yuan and Y. Yao, Chem.
Commun. (Camb), 2014, 50, 10952-10955.
C. J. Whiteoak, N. Kielland, V. Laserna, E. C. Escudero-Adan,
E. Martin and A. W. Kleij, J. Am. Chem. Soc., 2013, 135
,
1
228-1231.
3
5
W. Y. Gao, Y. Chen, Y. Niu, K. Williams, L. Cash, P. J. Perez, L.
Wojtas, J. Cai, Y. S. Chen and S. Ma, Angewandte Chemie,
2
014, 53, 2615-2619.
6
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Dalton Transactions
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DOI: 10.1039/C7DT03574H
Graphic Abstract
A series of Ln-CPs shows highly heterogeneous catalytic activity for cycloaddition reactions with
-1
TON = 3920 and TOF = 326h .