Removable bidentate directing group assisted-recyclable metal.organic frameworks-catalyzed direct oxidative amination of Sp2 C-H bonds

Article abstract of DOI:10.1016/j.jcat.2014.09.015

Several Cu-MOFs were showed to be efficient heterogeneous catalysts for ortho-amination of benzoic acid derivative C-H bonds by N-H amines using 8-aminoquinoline as bidentate directing group. The optimal reaction conditions involve the use of Cu-MOFs (25%

Full text of DOI:10.1016/j.jcat.2014.09.015

Journal of Catalysis 320 (2014) 9–15
Contents lists available at ScienceDirect
Journal of Catalysis
journal homepage: www.elsevier.com/locate/jcat
Removable bidentate directing group assisted-recyclable metal–organic
frameworks-catalyzed direct oxidative amination of Sp2 C–H bonds
⇑
Nga T.T. Tran, Quan H. Tran, Thanh Truong
Department of Chemical Engineering, HCMC University of Technology, VNU-HCM, 268 Ly Thuong Kiet, District 10, Ho Chi Minh City, Viet Nam
a r t i c l e i n f o
a b s t r a c t
Article history:
Several Cu-MOFs were showed to be efficient heterogeneous catalysts for ortho-amination of benzoic acid
derivative C–H bonds by N–H amines using 8-aminoquinoline as bidentate directing group. The optimal
reaction conditions involve the use of Cu-MOFs (25%), N-methylmorpholine oxide (NMO) as an oxidant,
secondary or primary amine coupling partner, DMF, DMA, or NMP solvent at 90–100 °C. Furthermore, the
Cu-MOFs catalyst could be facilely isolated from the reaction mixture and reused several times without
remarkable degradation in catalytic reactivity. Contribution from homogeneous leached active copper
species, if any, is negligible. To the best of our knowledge, C–H activation reactions using bidentate
directing groups, which are increasingly gaining importance, under heterogeneous catalytic systems
were not previously mentioned in the literature.
Received 18 June 2014
Revised 16 September 2014
Accepted 18 September 2014
Keywords:
Metal–organic frameworks
C–H activation
Copper-catalyzed
Direct amination
8-Aminoquinoline
Ó 2014 Elsevier Inc. All rights reserved.
1. Introduction
copper-mediated directed amination of C–H arene bonds was
described by Yu group [16]. However, stoichiometric amount of
Transition metal-catalyzed carbon–nitrogen coupling reactions
have offered widespread applications in the synthesis of many
valuable substrates including pharmaceutical compounds, func-
tional materials, and organic sensors [1–3]. Pre-functionalization
of starting materials either in the aminated substrates or in the
amines is required when conventional methods are employed
either in homogeneous or heterogeneous manners [4,5]. Conse-
quently, this adds up more chemical steps in the synthetic
sequences which can significantly lengthen the procedures. From
synthetic point of views, the direct coupling reactions from C–H
and N–H are highly desired (Scheme 1) [6–8]. Since organic mole-
cules often contain a wide range of chemically similar C–H bonds,
selective transformations for non-activated C–H bonds are gener-
ally difficult to achieve [9,10]. Several approaches have been
employed to address this challenge, the most common involves
the use of directing groups, which bind to the metal center and
bring catalysts to the proximal C–H bonds. Over last several years,
a wide variety of functional groups have been evaluated as direct-
ing groups in the transformation of C–H bonds [11,12]. Homoge-
neous palladium, iridium, and ruthenium based catalysts have
been employed for ligand-assisted direct amination of C–H bonds
of [13–15]. Recently, reactivity enabled by cheap and abundant
copper catalysts has attracted great interest. In particular, the first
copper is required and only 2-phenylpyridine derivatives were
active [17–19]. Recently, with the use of 8-aminoquinoline (8-
AQ) directing group [20,21], Daugulis has firstly reported that
ortho-amination of sp2 C–H bonds is possible under copper cataly-
sis [22]. The utilization of an inexpensive copper catalyst and
removable directing group allows for a favorable comparison with
previous direct amination methodologies. Thus, the heterogeneous
catalytic system for this transformation should be targeted for
practical chemical industry as well as simplifying the product puri-
fication [23,24].
Metal–organic frameworks (MOFs) have recently emerged as an
incredible class of crystalline porous materials with potential
applications in different fields [25–28]. Although the utilization
of MOFs in catalysis is a young research area, many MOFs have
been investigated as heterogeneous catalysts or catalyst supports
for a variety of organic transformations [29–32]. Recently, the
use of MOFs and other heterogeneous systems with transition
metal clusters for organic transformations, especially C–H func-
tionalization reactions have increasingly gained attention [33,34].
With respect to MOFs catalysis, Sanford and Swartzers have pio-
neered using Pd-MOFs for arylation of naphthalene by arene C–H
bonds [34a]. Bipyridyl-containing metal–organic frameworks of
palladium and iridium were demonstrated as efficient catalysts
for borylation of aromatic C–H bonds [34b]. However, regioisomers
were obtained in many cases where steric effect is not predomi-
nant. Our group has described the deprotonative arylation of
⇑
Corresponding author.
E-mail address: tvthanh@hcmut.edu.vn (T. Truong).
http://dx.doi.org/10.1016/j.jcat.2014.09.015
0021-9517/Ó 2014 Elsevier Inc. All rights reserved.

10
N.T.T. Tran et al. / Journal of Catalysis 320 (2014) 9–15
Scheme 1. Methods for transition metal-catalyzed C–N bond formation.
Table 1
Reaction condition development .a
N
N
HN
O
Cu(BTC)
HN
O
H N
O
NMO Oxidant
6 h
N
H
Entry
Temperature (°C)
Amount of catalyst (%)
Solvent
Ratio
GC yield (%)
1
2
3
4
5
6
7
8
100
110
90
90
90
90
90
90
90
90
90
90
90
25
25
25
20
25
25
25
25
25
25
25
25
25
NMP
NMP
NMP
NMP
DMA
DMF
Dioxane
p-xylene
NMP
NMP
NMP
2
2
2
2
2
2
2
2
1
3
0.5
2
2
73
59
73 (65)
55
71
62
9
<2
66
71
44
9
10
11
12b
13c
NMP
NMP
81 (71)
99 (87)
Bold texts indicated the optimal conditions. These optimal conditions were further used in next studies.
a
Volume of solvent 5 mL, 1.0 mmol scale, 6 h. Conversion by GC analysis.
Reaction for 12 h.
With AgOAc (20%) additive. Numbers in parentheses indicate the isolated yields. Kinetic studies of entries were placed in Supporting Information.
b
c
Table 2
reactions have not been reported in the literature. Herein, we pres-
ent the amination of ortho-aromatic C–H bonds using bidentate 8-
aminoquinoline directing group under Cu-MOF catalysis. Similar
isolated yields were obtained as compared to reports using homo-
geneous catalysts. Additionally, catalysts were able to be recycled
and reused several times by simple filtration or centrifugation
without significant degradation in catalytic activity.
Effect of silver salt additives to reaction yields.
Entry
Additive
Oxidant (2 equiv.)
GC yield
1
AgOAc
AgOAc
AgOAc
Ag2CO3
AgF
AgNO3
Silica-supported silver
AgOAc
AgOAc
O2
NMO
NMO
NMO
NMO
NMO
NMO
NMO
–
99
92
95
99
92
73
94
14
23
73
2a
3b
4
5
6
7
2. Experimental
8c
9d
10
–
NMO
All Cu-MOFs were synthesized according reported literature
(See Supporting Information for details) [38–43]. In addition, pro-
cedures for making all N-arenoyl-8-aminoquinoline were obtained
from previous studies and placed in Supporting Information
[21,44].
In a typical procedure, a mixture of N-benzoyl-8-aminoquino-
line (0.124 g, 0.5 mmol), morpholine (0.087 g, 1 mmol) and
diphenyl ether (0.055 mL) as an internal standard in N-methyl-2-
pyrrolidone (NMP, 5 mL) were added into 25-mL flask containing
the predetermined amount of Cu-MOF catalyst and N-methylmor-
pholine oxide (NMO, 0.087 g, 1 mmol) as an oxidant. The catalyst
Reaction conditions: amide (0.5 mmol), amine (1 mmol), MOF-199 (25 mol%,
25.2 mg), AgOAc (25 mol%), NMO (2 equiv., 117 mg) in 5 mL NMP at 90 °C for 6 h.
a
10 mol% AgOAc was used.
50 mol% AgOAc was used.
1 equiv. AgOAc was used.
2 equiv. AgOAc was used.
b
c
d
variety of heterocycles using Cu-MOFs [35–37]. Despite the impor-
tance of ligand-assisted C–H activation reactions, especially in con-
trolling regioselectivity, conditions using MOFs for these types of

N.T.T. Tran et al. / Journal of Catalysis 320 (2014) 9–15
11
Table 3
3. Results and discussion
Effect of various oxidant.a
Entry
Oxidant
GC yield (%)
Cu3(BTC)2, (BTC = 1,3,5-benzenetricarboxylic acid), MOF-199,
which was mostly used in this work, were fully characterized by
several techniques including X-ray powder diffraction (XRD), scan-
ning electron microscope (SEM), thermogravimetric analysis
(TGA), Fourier transform infrared (FT-IR), inductively coupled
plasma (ICP), and nitrogen physisorption measurements
(Figs. S11–S17). The microscopic results are in agreement with
the previous reports [36]. In particular, Cu-MOFs were highly crys-
talline in the cubic shape. TGA showed that the reduced mass at
reaction temperature (90–110 °C) was negligible. All other MOFs
synthesized according to previous reports were characterized by
XRD and FT-IR to confirm the catalyst structure (Figs. S1–S10)
[38–43].
In optimization screening, commercially available MOF-199
was chosen as catalyst for the reactions between N-benzoyl-8-
amino-quinoline and morpholine using previously used NMO oxi-
dant (Table 1). Kinetic studies of entries were placed in Supporting
Information. With respect to reaction temperature, similar results
were obtained at 100 °C and 90 °C (entries 1, 3). Increasing temper-
ature resulted in the moderately drop in reaction conversion (entry
2). Catalyst loading of 20% gave only 55% conversion (entry 4). Sim-
ilar to NMP solvent, acyclic amide solvent such as DMA or DMF
afforded about 70% product (entries 5, 6). Other solvents such as
dioxane and p-xylene which were showed to be insufficient with
less than 10% of product were obtained (entries 7, 8). Furthermore,
increasing or decreasing molar ratio of amine/arene C–H bonds
slightly slowed down the reaction (entries 9–11). Interestingly,
reaction at longer time, 12 h, gave 81% GC yield (entry 12). Similar
to reported optimal conditions with homogeneous catalyst in
which 25% silver salt additive was required [22], quantitative con-
version was achieved when 20% AgOAc was added (entry 13). High
reaction selectivity was confirmed by the closed numbers of GC
yields and the isolated yields (entries 3, 12, 13).
1
2
3
4
5
6
K2S2O8
Dicumyl peroxide
Tert-butylbenzoyl peroxide
H2O2
O2
<5
28
25
<2
22
31
Air
a
Volume of solvent 5 mL, 1.0 mmol scale, 6 h. Kinetic studies of entries were
placed in Supporting Information.
loading was calculated with respect to the copper/N-benzoyl-8-
aminoquinoline molar ratio. The reaction mixture was stirred at
90 °C for 6 h. In kinetic studies, reaction conversion was monitored
by withdrawing aliquots from the reaction mixture at different
time intervals and quenching with an aqueous KOH solution (5%,
1 mL). The organic components were then extracted into ethyl ace-
tate (2 mL), dried over anhydrous Na2SO4, and analyzed by GC with
reference to diphenyl ether. The product characterization was con-
firmed by GC–MS and NMR.
To investigate the recyclability of Cu-MOFs, the catalyst was
separated from the reaction mixture by simple centrifugation
and decantation, washed thoroughly with DMF followed by etha-
nol, dried under vacuum at 140 °C for 6 h, and reused. For the
leaching test, a catalytic reaction was stopped after 30 min, ana-
lyzed by GC, and hot filtrated to remove the solid catalyst. The
reaction solution was then stirred for a further 330 min. Reaction
progress, if any, was monitored by GC as previously described. In
addition, reactions using Poly(vinylpyridine) resin (20% mol) were
carried out to further confirm the heterogeneity of catalysts. Three
phase test with mercury (0) was also conducted to clarify the cat-
alytic active species in reaction process.
Table 4
Reactivity of other catalysts.a
N
N
Catalyst (25%)
HN
O
HN
O
H
N
O
NMO
NMP,
(2 equiv.)
N
H
90 o 6h
C,
2
equiv.
Entry
Type
Catalyst
GC yield (%)
1
Cu-MOFs
MOF-199
73 (99) (TOFb = 34)
2
3
4
5
CuBDC
78 (97)
79 (93)
50 (92)
68 (88)
5 (6)
Cu2(BDC)(DABCO)
Cu2(BPDC)(BPY)
Cu2(PDA)(BPY)
Ni3(BTC)2
6
Other MOFs
7
8
10
11
12
Co-MOF-74
Mn2(BDC)2(DMF)2
Cu(OCOPh)2
Cu(NO3)2
<2
<2
Common salts
62 (84) (TOFb = 4.8)
65 (86)
47 (79)
CuCl2
a
Volume of solvent 5 mL, 1.0 mmol scale, 6 h. Kinetic studies of entries were placed in Supporting Information.
Calculated at initial reaction rate (without AgOAc) as moles of product formed per hour and per mole of Lewis acidic active site (hÀ1). Numbers in parentheses indicated
b
the GC yields with 20% added AgOAc.

12
N.T.T. Tran et al. / Journal of Catalysis 320 (2014) 9–15
Table 5
Reactions scope of coupling components.
R2
R3
O
AQ
R1
O
AQ
R1
R2
N
Cu(BTC) (25%)
HN
H
=
AQ
R3
NMO
N
(2 equiv.)
90 o 6h
HN
NMP,
C,
2
equiv.
Entry
1
Benzoic derivative
Amine
Product
Yields (%)
65
O
O
AQ
AQ
82a
78a,b
O
HN
O
O
N
2
61
O
O
AQ
AQ
85a
O
HN
N
OCH3
O
OCH3
3
4
50
57
O
AQ
AQ
AQ
O
O
HN
HN
O
O
N
N
Me
Me
AQ
O
O
Me
Me
Me
Me
5
67
40
O
O
AQ
AQ
O
HN
O
N
F
F
CF3
CF3
3C
AQ
3C
6
7
O
O
O
AQ
AQ
O
HN
HN
O
O
N
60
O
AQ
78a
O
N
CF3
CF3
8
41a
O
O
AQ
AQ
NH2
H
N

N.T.T. Tran et al. / Journal of Catalysis 320 (2014) 9–15
13
Table 5 (continued)
Entry
9
Benzoic derivative
Amine
Product
Yields (%)
72a
O
O
O
O
H
N
O
O
O
O
AQ
AQ
AQ
AQ
AQ
AQ
AQ
AQ
N
N
N
N
10
11
12
81a
88a
40
H
N
Ph
N
H
Ph
H
N
Ph
Ph
Conditions: DMA (4 mL), amide (0.5 mmol).
a
Reactions with added AgOAc (20%).
5 mmol scale.
b
To clarify the role of additive AgOAc on the reaction process,
several control experiments were conducted (Table 2). Particularly,
reaction with 50% AgOAc afforded slightly lower yield than reac-
tion with 20% (entries 1, 3). Similar results were obtained when
only 10% AgOAc was employed (entry 2). Reactions with different
silver salts including Ag2CO3, AgF, and AgNO3 were also performed
(entries 4–6). Interestingly, silver immobilized on silica gel was
active and 94% GC yield was achieved (entry 7). When AgOAc
was employed in stoichiometric amount and in the absence of
NMO, significant drop on reaction rate was observed (entries 8,
9). Reaction under oxygen atmosphere afforded similar yield with
reaction under argon without silver salt (entry 10). In pioneering
work, Daugulis proposed silver as cocatalyst for above transforma-
tion [22]. Additionally, silver salts were frequently used as cocata-
lyst in organic reactions under palladium catalysis [9,10]. Based on
previous reports and the aforementioned experimental results,
under our optimal conditions, silver salt is likely to play as cocata-
lyst in reaction process.
Effect of various oxidants on reaction yields was then investi-
gated (Table 3). In particular, inorganic oxidant K2S2O8 was not
suitable and no trace amount of product was detected (entry 1).
Additionally, peroxides such as tert-butylbenzoyl peroxide or
dicumyl peroxide gave similar results of about 25% conversion
(entries 2,3). However, simple hydrogen peroxide is not effective
(entry 4). Reaction under oxygen atmosphere did not afford rea-
sonable yield (entry 5). Similarly, low reaction yield was observed
when air was employed as reaction oxidant (entry 6). In pioneering
work from Daugulis group, NMO was also chosen as optimal oxi-
dant. The use of N-oxide oxidant is expected to promote the forma-
tion of Cu(III)-oxo complex intermediate [45].
Cu2(BPDC)(BPY) and Cu2(PDA)(BPY) with 50% and 68%, respec-
tively (entries 4,5). It is worth mentioning that other transition
metal-based organic frameworks such as Ni3(BTC)2, Mn2(BDC)2
(DMF)2 or Co-MOF-74 are not effective and unappreciable amount
of product was observed even AgOAc was employed (entries 6–8).
Interestingly, reaction using homogeneous copper (II) benzoate,
which is the ‘‘monomer’’ of Cu-MOFs, afforded lower yield, with
only 62%. Similar results were achieved when other common cop-
per salts, CuCl2, Cu(NO3)2, were employed. As expected, added
AgOAc remarkably enhances the reaction rate under copper
catalysis.
The generality of optimal conditions using Cu(BTC) on other
derivatives of coupling components is described in Table 5. Func-
tionality occurs at ortho position and mono-aminated products
were obtained in all cases. With respect to benzoic components,
amination of substituted C–H bonds with electron-withdrawing,
trifluoromethyl, or electron-donating groups, methyl and methoxy,
are possible and products were obtained in good conversions
(entries 2–7). In details, amination reaction of 8-AQ-benzamides
with substituents at meta-position afforded products in reasonable
conversions (entries 3–5). Reaction of morpholine with ortho-
substituted sp2 C–H bonds was also conducted and 40% conversion
was obtained (entry 6). In agreement with homogeneous work,
addition of silver salt significantly enhanced the reaction yields.
Cross-coupling reactions of cyclic secondary amine, piperidine
and pyrrolidine, resulted in aminated products in reasonable yields
(entries 9, 10). In addition, acyclic secondary N–H is active and
product was afforded in excellent yield (entry 11). Optimal condi-
tion is also applicable for mono-amination by primary amine and
41% product yield was achieved (entry 8). Interestingly, aromatic
amine, which was not active under homogeneous conditions, was
cross-coupled in moderate yield (entry 12).
We then decided to test the catalytic activity of several open
metal sites Cu-MOFs which have been frequently used as catalysts
for organic transformations (Table 4) [46–48]. Gratifyingly, several
Cu-MOFs such as CuBDC and Cu2(BDC)(DABCO) offered good activ-
ity (entries 2,3). Slightly lower conversions were obtained with
In terms of practical viewpoint, the reactions can be scaled up to
10-fold without significant loss of yield (Table 4, entry 1). Further-
more, 8-aminoquinoline auxiliary can be removed by base hydro-

14
N.T.T. Tran et al. / Journal of Catalysis 320 (2014) 9–15
Scheme 2. Bidentate directing group cleavage.
lysis. In particular, heating amide 1 with NaOH in methanol at ele-
vated temperature for 24 h afforded high yield of ortho-aminated
benzoic acid (Scheme 2).
clarify the actual active catalyst species, a control reaction with
added insoluble poly(vinylpyridine) (PVPy) resin was carried out
using MOF-199 catalyst. Poly(vinylpyridine) is well known to
remove free copper species from solution. Also, it is clearly that
PVPy is too big to enter the pore channel of Cu-MOFs catalyst.
The experimental results revealed that similar reaction conversion
was still achieved with 71% after 6 h in the presence of PVPy. Addi-
tionally, there was no significant change in reaction rate when pyr-
idine was added. Furthermore, under homogeneous CuI catalysis
and identical conditions, the catalysis was completely shut down
when PVPy resin was added. These data conclusively indicated that
the catalytic activity associated with the immobilized sites. There-
fore, it is unlikely that there was contribution from leached active
copper species. In additional, a three phase test in the presence of
mercury (0) was also conducted. Under optimal condition, a con-
version of 68% was obtained when 20% Hg (0) was used. This sug-
gested that a Cu(0)/Cu(II) catalytic cycle is unlikely.
In leaching test, a control experiment was carried out using a
simple hot filtration during the course of the reaction. The direct
C–H/N–H coupling reaction was then conducted under optimal
conditions. After 10 min with a conversion of 35% being detected,
the Cu-MOF catalyst was removed from the reaction mixture by
hot filtration. The liquid phase was then transferred to a new reac-
tor vessel, magnetically stirred for an additional 5.5 h at 90 °C with
aliquots being sampled at different time intervals, and analyzed by
GC. It was observed that no further conversion was detected in the
reaction mixture after the Cu-MOFs catalyst was separated from
the reaction mixture (Fig. 1). In addition, ICP-MS revealed less than
30 ppm of copper in the filtrate from reaction mixture. To further
Fig. 1. Leaching test.
Fig. 3. PXRD patterns of fresh (a) and reused (b) MOF-199.
Fig. 2. Catalyst recycling studies.
Fig. 4. FT-IR spectra of MOF-199 before (a) and after reused (b).

N.T.T. Tran et al. / Journal of Catalysis 320 (2014) 9–15
[12] F. Kakiuchi, S. Murai, Acc. Chem. Res. 35 (2002) 826.
15
The recoverability and reusability of the Cu-MOFs catalyst were
also targeted. After the experiment, the Cu-MOF catalyst was fil-
tered from the reaction mixture, washed with copious amounts
of DMF to remove any physisorbed reagents, dried at 140 °C under
vacuum in 6 h, and then reused in further reactions under identical
conditions to those of the previous runs. The results exhibited that
a conversion of 63% was still achieved after 180 min in the 5th run
(Fig. 2). Furthermore, PXRD and FT-IR of the reused catalyst after
the 5th run indicated that the change in catalyst crystallinity is
trivial, and the reused Cu-MOFs were still highly crystalline (Figs. 3
and 4).
[13] Y.S.H. Zhao, S. Weiping, Org. Lett. 15 (2013) 5106.
[14] D.G. Lee, Y.K.C. Sukbok, J. Org. Chem. 78 (2013) 1.
[15] E.J. Yoo, S. Ma, T.-S. Mei, K.S.L. Chan, J.-Q. Yu, J. Am. Chem. Soc. 133 (2011)
7652.
[16] X. Chen, X.-S. Hao, C.E. Goodhue, J.-Q. Yu, J. Am. Chem. Soc. 128 (2006) 6790.
[17] Uemura, S. Imoto, N. Chatani, Chem. Lett. 35 (2006) 842.
[18] A. John, K.M. Nicholas, J. Org. Chem. 76 (2011) 4158.
[19] Q. Shuai, G. Deng, Z. Chua, D.S. Bohle, C.-J. Li, Adv. Synth. Catal. 352 (2010) 632.
[20] G. Rouquet, N. Chatani, Angew. Chem. Int. Ed. 52 (2013) 11726.
[21] (a) T. Truong, K. Klimovica, O. Daugulis, J. Am. Chem. Soc. 135 (2013) 9432;
(b) L.D. Tran, O. Daugulis, Angew. Chem. Int. Ed. 51 (2012) 5188.
[22] L.D. Tran, J. Roane, O. Daugulis, Angew. Chem. Int. Ed. 52 (2013) 6043.
[23] C.E. Garrett, K. Prasad, Adv. Synth. Catal. 346 (2004) 889.
[24] C.J. Welch, A.-J. Walker, W.R. Leonard, M. Biba, J. DaSilva, D. Henderson, B.
Laing, D.J. Mathre, S. Spencer, X. Bu, T. Wang, Org. Process Res. Dev. 9 (2005)
198.
4. Conclusions
[25] D.J. Tranchemontagne, M.O.k.Z. Ni, O.M. Yaghi, Angew. Chem. Int. Ed. 47
(2008) 5136.
In conclusion, we have described a method for auxiliary-
assisted direct amination of b-sp2 C–H bonds of benzoic acid
derivatives under several Cu-MOFs catalysis. The optimal reaction
conditions involve the use of NMO as an oxidant, secondary or
primary amine coupling partner, DMF, DMA, or NMP solvent at
90–100 °C. Broad substrate scope is compatible under reported
conditions. The method is advantageous compared to the existing
routes due to utilization of heterogeneous copper catalyst and a
removable bidentate directing group, which has not been
previously described under heterogeneous catalytic systems. In
addition, Cu-MOFs were showed to be recovered and reused
several times without a significant degradation in catalytic activity
and contribution from homogeneous leached active copper species,
if any, is negligible.
[26] R.J. Kuppler, D.J. Timmons, Q.-R. Fang, J.-R. Li, T.A. Makal, M.D. Young, Coord.
Chem. Rev. 253 (2009) 3042.
[27] H.-C. Zhou, J.R. Long, O.M. Yaghi, Chem. Rev. 112 (2012) 673.
[28] M. O’Keeffe, O.M. Yaghi, Chem. Rev. 112 (2012) 675.
[29] M. Yoon, R. Srirambalaji, K. Kim, Chem. Rev. 112 (2012) 1196.
[30] J. Gascon, A. Corma, F. Kapteijn, F.X. Llabrés i Xamena, ACS Catal. 4 (2014) 361.
´
´
[31] A. Corma, H. Garcıa, F.X. Llabres i Xamena, Chem. Rev. 110 (2010) 4606.
[32] Z.-Y. Gu, J. Park, A. Raiff, Z. Wei, H.-C. Zhou, ChemCatChem 6 (2014) 67.
[33] (a) S. Kawamorita, R. Murakami, T. Iwai, M. Sawamura, J. Am. Chem. Soc. 135
(2013) 2947–2950;
(b) S. Kawamorita, H. Ohmiya, K. Hara, A. Fukuoka, M. Sawamura, J. Am. Chem.
Soc. 131 (2009) 5058–5059;
(c) S. Kawamorita, T. Miyazaki, T. Iwai, H. Ohmiya, M. Sawamura, J. Am. Chem.
Soc. 134 (2012) 12924–12927;
(d) N.T.S. Phan, C.W. Jones, J. Mol. Catal. A: Chem. 253 (2006) 123–131;
(e) F. Wu, Y. Feng, C.W. Jones, ACS Catal. 4 (2014) 1365–1375;
(f) S. Kawamorita, T. Miyazaki, H. Ohmiya, T. Iwai, M. Sawamura, J. Am. Chem.
Soc. 133 (2011) 19310–19313.
[34] (a) K. Manna, T. Zhang, W. Lin, J. Am. Chem. Soc. 136 (2014) 6566;
(b) D.T. Genna, A.G.W. Foy, A.J. Matzger, M.S. Sanford, J. Am. Chem. Soc. 135
(2013) 10586.
Acknowledgments
[35] N.T.S. Phan, T.T. Nguyen, P.H.L. Vu, ChemCatChem 5 (2013) 3068.
[36] (a) D. Britt, D. Tranchemontagne, O.M. Yaghi, PNAS 33 (2008) 11623;
(b) H.T.N. Le, T.T. Nguyen, P.H.L. Vu, T. Truong, N.T.S. Phan, J. Mol. Catal. A 391
(2014) 74.
The Viet Nam National Foundation for Science and Technology
Development - is acknowledged for financial support.
[37] N.T.S. Phan, C.K. Nguyen, T.T. Nguyen, T. Truong, Catal. Sci. Technol. (2014),
http://dx.doi.org/10.1039/C3CY00503H.
[38] C.G. Carson, K. Hardcastle, J. Schwartz, X. Liu, C. Hoffmann, R.A. Gerhardt, R.
Tannenbaum, Eur. J. Inorg. Chem. 48 (2009) 2338–2343.
[39] K. Tan, N. Nijem, P. Canepa, Q. Gong, J. Li, T. Thonhauser, Y.J. Chabal, Chem.
Mater. 24 (2012) 3153–3167.
[40] P. Mishra, S. Edubilli, B. Mandal, S. Gumma, Micropor. Mesopor. Mater. 169
(2013) 75–80.
[41] K. Seki, W. Mori, J. Phys. Chem. B 106 (2002) 1380–1385.
[42] S. Achmann, G. Hagen, M. Hämmerle, I. Malkowsky, C. Kiener, R. Moos, Chem.
Eng. Technol. 33 (2010) 275–280.
[43] Z. Chen, Q. Zhao, W. Xiong, Z. Zhang, F. Liang, Z. Anorg, Allg. Chem. 636 (2010)
2691–2697.
[44] L.D. Tran, I. Popov, O. Daugulis, J. Am. Chem. Soc. 134 (2012) 18237.
[45] M.T. Kieber-Emmons, J.W. Ginsbach, P.K. Wick, H.R. Lucas, M.E. Helton, B.
Lucchese, M. Suzuki, A.D. Zuberbühler, K.D. Karlin, E.I. Solomon, Angew. Chem.
Int. Ed. 53 (2014) 4935.
Appendix A. Supplementary material
Supplementary data associated with this article can be found, in
the online version, at http://dx.doi.org/10.1016/j.jcat.2014.09.015.
References
[1] F. Collet, C. Lescot, P. Dauban, Chem. Soc. Rev. 40 (2011) 1926.
[2] J.L. Roizen, M.E. Harvey, J. Du Bois, Acc. Chem. Res. 45 (2012) 911.
[3] T.A. Ramirez, B. Zhao, Y. Shi, Chem. Soc. Rev. 41 (2012) 931.
[4] D.N. Zalatan, J. Du Bois, Topics in Current Chemistry, in: J.-Q. Yu, Z. Shi (Eds.),
vol. 292, Springer, Berlin, 2010, p. 347.
[5] A.N. Vedernikov, K.G. Caulton, Chem. Commun. (2004) 162.
[6] Q. Wang, S.L. Schreiber, Org. Lett. 11 (2009) 5178.
[46] N.T.S. Phan, T.T. Nguyen, V.T. Nguyen, K.D. Nguyen, ChemCatChem 5 (2013)
2374.
[47] N.T.S. Phan, T.T. Nguyen, P. Ho, K.D. Nguyen, ChemCatChem 5 (2013) 1822.
[48] P.G. García, M. Müllera, A. Corma, Chem. Sci. (2014). 10.1039/C4SC00265B.
[7] T. Kawano, K. Hirano, T. Satoh, M. Miura, J. Am. Chem. Soc. 132 (2010) 6900.
[8] S.H. Cho, J. Yoon, S. Chang, J. Am. Chem. Soc. 133 (2011) 5996.
[9] T.W. Lyons, M.S. Sanford, Chem. Rev. 111 (2010) 1147.
[10] O. Daugulis, H.-Q. Do, D. Shabashov, Acc. Chem. Res. 42 (2009) 1074.
[11] D.A. Colby, A.S. Tsai, R.G. Bergman, J.A. Ellman, Acc. Chem. Res. 45 (2012) 814.