Zr-MOF-808 as Catalyst for Amide Esterification

Article abstract of DOI:10.1002/chem.202003752

In this work, zirconium-based metal–organic framework Zr-MOF-808-P has been found to be an efficient and versatile catalyst for amide esterification. Comparing with previously reported homogeneous and heterogeneous catalysts, Zr-MOF-808-P can promote the reaction for a wide range of primary, secondary and tertiary amides with n-butanol as nucleophilic agent. Different alcohols have been employed in amide esterification with quantitative yields. Moreover, the catalyst acts as a heterogeneous catalyst and could be reused for at least five consecutive cycles. The amide esterification mechanism has been studied on the Zr-MOF-808 at molecular level by in situ FTIR spectroscopic technique and kinetic study.

Full text of DOI:10.1002/chem.202003752

Accepted Article
Accepted Article
Title: Zr-MOF-808 as Catalyst for Amide Esterification
Authors: Avelino Corma, Beatriz Villoria-del-Álamo, Sergio Rojas-Buzo,
and Pilar García-García
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To be cited as: Chem. Eur. J. 10.1002/chem.202003752
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1/2020

Chemistry - A European Journal
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Zr-MOF-808 as Catalyst for Amide Esterification
Beatriz Villoria-del-Álamo, Sergio Rojas-Buzo, Pilar García-García*[a,b] and Avelino Corma*[a]
[
a]
[a]
[
a]
B. Villoria-del-Álamo, Dr. S. Rojas-Buzo, Dr. P. García-García, Prof. Dr. A. Corma
Instituto de Tecnología Química, UPV-CSIC, Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas
Avenida de los Naranjos, s/n, 46022, Valencia, Spain
E-mail: acorma@itq.upv.es
[
b]
Dr. P. García-García
Present address: Departamento de Ciencias Farmacéuticas, Facultad de Farmacia, CIETUS, IBSAL
Campus Miguel de Unamuno, University of Salamanca, 37007, Spain
E-mail: pigaga@usal.es
Supporting information for this article is given via a link at the end of the document.
into esters using fluoride as catalyst (Scheme 1).22 This halide is
a strong nucleophile, which interacts with the amide carbonyl
group to generate an acyl fluoride intermediate. The last one is
more reactive than the amide group, allowing the nucleophilic
attack of alcohol to the carbonyl group.
Abstract: In this work, zirconium-based metal-organic framework
Zr-MOF-808-P has been found to be an efficient and versatile catalyst
for amide esterification. Comparing with previously reported
homogeneous and heterogeneous catalysts, Zr-MOF-808-P can
promote the reaction for a wide range of primary, secondary and
tertiary amides with n-butanol as nucleophilic agent. Different alcohols
have been employed in amide esterification with quantitative yields.
Moreover, the catalyst acts as a heterogeneous catalyst and could be
reused for at least five consecutive cycles. The amide esterification
mechanism has been studied on the Zr-MOF-808 at molecular level
by in situ FT-IR spectroscopic technique and kinetic study.
Introduction
Amide is one of the most robust groups1 present in nature (in
proteins,2 drugs3 and other synthetic products4). Under
physiological conditions (neutral pH and room temperature), the
amide bond half-life is around 350-600 years.5,6,7 Due to the
extreme inertness associated with their resonance stabilization,
the amide bond cleavage has been studied extensively in the last
decades,8,9,10,11,12,13,14,15 and amide esterification with alcohols is
a versatile strategy to convert amides into useful synthetic
building blocks. Examples of this are picolinic acid or niacin
derivate aromatic ester, which are active for apoptosis of human
leukaemia cells and rubefacients prodrugs, respectively.16,17 In
nature, protease enzymes can perform peptide bond hydrolysis in
proteins through an ATP-dependent process. Inspired by the
confined space and active sites of these enzymes (based on
transition metals), inorganic artificial systems have been
synthesized.18,19 However, the methodologies employed for
amide esterification require severe conditions, high metal-loading
and, in some cases, produce low yields of the desired product due
to the low reactivity of the amides (poor electrophiles), the
reduced nucleophilicity of the alcohols and the higher
thermodynamic stability of the substrates compared with the
products.
Different strategies for the esterification of specific activated
amides (twisted or distorted) have been postulated using
homogeneous catalysts.20,21 Functionalized secondary or tertiary
amides, such as N-acyl-tert-butyl-carbamates, N-acyl-
tosylamides or di-tert-butyl-N-acylimidocarbonates, are converted
Scheme 1. Representative examples using homogeneous and heterogeneous
methodologies for amide esterification.
1
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Transition metals have been employed as catalysts in
esterification reactions. Garg’s group has demonstrated the
amide activation with a nickel catalyst by an oxidative addition
mechanism (Scheme 1).23,24,25,26 Inorganic salts containing Cu (II)
mechanism for the amide esterification reaction has been
proposed based on kinetic models and in situ FT-IR studies.
have been explored for the activation of amides, where the Results and Discussion
transition metal coordinates the nitrogen atom inducing a
significant distortion in the structure. Bannwarth et al. gave a
practical approach to this strategy, performing a methodology for
the protection and deprotection of aromatic carboxylic acids
through N,N-bis(2-picolyl)amide systems.27,28,29
Zr - based MOFs as catalysts for amide esterification
Previous studies have described the utilization of various MOFs
as heterogeneous catalysts for the amide hydrolysis.43,49
However, it’s the first time that MOFs are used as catalysts for
amide esterification. Our attention has been focused on different
zirconium- and hafnium-based MOFs for catalytic amide
In the last decade, a few examples of the amide esterification
catalyzed by heterogeneous catalysts have been reported. In
2
014, the role of cerium oxide as heterogeneous catalyst in the
amide esterification was described.30,31 Shimizu et al. provided a
strategy for the amide alcoholysis employing CeO at 165 °C
under inert atmosphere (Scheme 1). The authors proposed that
the synergy between Lewis acid and base sites on CeO surface
favors the activation of the amide group. The esterification
reaction mechanism catalyzed by CeO has been demonstrated
esterification due to their potential physico-chemical properties.
3
Zr-MOF-808, with the nominal chemical formula Zr
6
(µ -O)
4
2
µ3-OH)
(
-(BTC) (HCOO) , was described for the first time in
4 2 6
014.50 Each metallic cluster is 6-connected in a spn topology and
2
2
its framework generates tetrahedral and adamantane-like cages
4.8 and 18.4 Å, respectively Table 1). Zr-MOF-808-P51 has been
(
2
prepared following recently reported adapted procedure, using 3
equivalents of ZrCl per each equivalent of organic linker (1,3,5-
benzenetricarboxylic acid, H BTC) to increase potential active
sites, while Zr-MOF-808 has been synthesized from 1 equivalent
of ZrCl per each equivalent of organic linker. Isoreticular Hf-
MOF-80844 has been prepared here using HfCl
, as metal source.
by density functional theory calculations, in situ FT-IR
spectroscopy and catalytic studies. We will show later the much
higher activity and selectivity for amide esterification of the
Zr-MOF-808 proposed here.
4
3
4
Metal-organic frameworks (MOFs) are a class of materials built
from metallic clusters and organic linkers via coordination
bonds.32 The most attractive features of MOFs are their intrinsic
properties, such as crystalline nature, high porosity, stability and
surface area.33,34 MOF-based materials have been found to be
suitable catalysts to produce certain products with high industrial
value due to their functional active sites along with the potential
inner porosity that allows guest molecules to access the
pores.35,36,37 MOFs show high versatility thanks to the ability of
modifying the organic linker and metal node, which offers a fine-
tune control of the pore size or their inherent Lewis acidity,
allowing the design of more selective processes.38,39,40,41,42
Recently, HKUST-1 (Cu (II)) has shown a mimetic activity of
trypsin enzyme for the hydrolysis of bovine serum and casein
albumin.43 However, this solid is moisture sensitive, presenting a
limited stability. Zirconium- and hafnium-based MOFs have
demonstrated a remarkably better stability and robustness,
compared with MOFs presenting other transition metals.44
Indeed, the activity and stability of these MOFs have been
demonstrated even in the presence of water and organic
acids.45,46,47,48 Interestingly, Zr-MOF-808 has been used as an
effective heterogeneous catalyst for peptide bond hydrolysis of a
series of dipeptides.49 The reaction mechanism involves the
interaction of the amino acid terminal groups with the MOF ligands
4
Table 1. Structural characteristics of different MOFs and their metallic clusters
Colour code.
Blue: metal;
Metal cluster
Red: oxygen;
Grey: hydrogen
MOF-808
M O (OH)
UiO-66
MOF-801
M O (OH)
6
4
4
M O (OH)
6
4
4
6
4
4
Formula
Ligand
(
BTC)
2
(HCOO)
6
(BDC)
6
(FA)
6
1
2-
Connectivity
Pore size
6-connected
12-connected
connected
8.4 and
11 Å
5.6 and
7.4 Å
4.8 and 18.4 Å
(Zr-MOF)
Besides MOF-808, we have also evaluated other MOF structures,
such as UiO-6652 and MOF-801.53 Zr-UiO-66 consists of a
12-connected (1,4-benzenedicarboxylate, BDC) zirconium cluster
while Zr-MOF-801 contains twelve fumarate linkers (FA). Both
MOF structures have a fcu topology with tetrahedral and
octahedral cages (8.4 and 11 Å for Zr-UiO-66 and 5.6 and 7.4 Å
for Zr-MOF-801, Table 1). Considering this, their confined space
will be smaller than in the case of Zr-MOF-808. These materials
were prepared using a similar synthetic procedure to anticipate a
similar degree of defects in their frameworks.
to activate the amide bond.
Based on our preliminary research,45,46 we propose the use
of MOFs containing group 4 metals (zirconium and hafnium)
as artificial enzyme-type materials for amide esterification
reaction, since they present the adequate confined spaces
and active sites to undergo this target reaction (Scheme 1).
These solids have been exhaustively characterized, with
emphasis on determining their active sites. Furthermore, a
wide scope of esterification reactions with different
functionalized amides and alcohols has been studied. A
All these prepared materials have been characterized and the
obtained data correlate well with the characterization reported
2
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FULL PAPER
previously in the literature. In general, the solids have shown high
surface area, crystallinity and excellent thermal stability (See
Supporting Information, section 2.1 and 2.2.1).
connectivity at the Zr clusters of the formers along with their
smaller cages, fact that would mostly prevent the diffusion and
stabilization of the reactants. In line with this, it should be noted
that a higher meso/microporous ratio is observed in Zr-MOF-801
versus Zr-MOF-808. In view of the poor catalytic activity of the
former, cluster connectivity appears decisive for the catalytic
performance. The related Hf-based MOFs exhibit lower activity
compared to the Zr counterparts (Table 2. Entries 4, 6 and 8
versus Entries 2, 5, and 7) once again attributed to the
differences in the acid-base properties of the metal cluster. Then,
it was accounted that Zr-MOF-808 has an adequate equilibrium
between confined space and acid-base properties to promote the
reaction. Regarding this, further details are shown below with the
analysis of the acidic active sites in these MOFs by means of
FT-IR spectroscopy using CO as probe molecule together with a
mechanistic study by in situ FT-IR spectroscopy.
The prepared zirconium- and hafnium-based MOFs were tested
in the esterification reaction of benzamide with n-butanol, using
2
5 mol% metal loading at 150 °C. The reaction was followed over
time by gas chromatography. The highest activity was observed
for Zr-MOF-808-P (Figure 1), fact that could be expected due to
the lower connectivity within the structure (Table 1).
Zr-MOF-808-P
Zr-MOF-808
Zr-UiO-66
100
For
precursor), ZrO
as catalysts (Table 2. Entry 9, 10 and 11, respectively). The initial
reaction rate obtained with the inorganic precursor ZrCl was
a
comparative purpose, the sub-units ZrCl
4
(metallic
Hf-MOF-808-P
8
0
0
0
0
Hf-MOF-808
Zr-MOF-801
and Zr -benzoate were employed in the reaction
2
6
6
4
2
4
comparable to that of Zr-MOF-808-P, but the reaction stopped
after reaching 40 % yield, which indicates catalyst deactivation. In
the case of ZrO
2
, the activity is considerably lower compared to
the rest of materials. Zr
6
-benzoate shows a similar molecular
cluster to Zr-MOF-808, however, the attained yield was 43 %.
Zr-MOF-808-P was also tested at lower loading (10 mol%)
affording in this case 35 % yield of the desired product under
identical reaction conditions (data not shown) pointing to the
convenience of using 25 mol% loading to achieve high yields in
reasonable reaction times.
1
00
Zr-MOF-808-P
Zr-MOF-808
ZrCl4
Without
ZrO2
8
0
0
0
0
6
4
2
Table 2. Solvolysis of benzamide with n-BuOH with different catalysts.
r
o
%C[a]
%Y[a]
TOF (h-1)
Catalyst
TON
(
mM/h)
62.0
37.4
4.2
1
2
3
4
5
6
7
8
9
Zr-MOF-808-P
Zr-MOF-808
Hf-MOF-808-P
Hf-MOF-808
Zr-UiO-66
100
91
49
28
55
48
35
16
64
23
46
18
99
90
29
23
51
26
8
4.0
3.5
1.5
0.9
2.1
1.0
0.3
1.0
1.5
0.1
1.74
0.1
0.496
0.299
0.034
0.029
0.086
0.031
0.013
0.007
0.513
0.003
n.d.
0
0
5
10
15
time (h)
20
25
Figure 1. Kinetic study of the solvolysis of benzamide with n-butanol with
several catalysts. Reaction conditions: Amide 1a (0.3 mmol), catalyst
0.075 mmol, 25 mol%), n-butanol (0.6 ml, 0.5 M), 150 °C, n-dodecane
0.05 mmol) as external standard.
3.5
10.7
3.9
(
(
Hf-UiO-66
The calculated initial rate when using Zr-MOF-808-P was
2.0 mM/h (Table 2. Entry 1), which was 1.7 times higher
Zr-MOF-801
Hf-MOF-801
2.2
6
2
0.5
compared to Zr-MOF-808 (Table 2. Entry 2). This difference in
activity could be attributed to the lower number of active sites in
the Zr-MOF-808 that shows lower degree of linker defects (as it
will be discussed in the next section). In the case of Hf-MOF-
ZrCl
ZrO
-benzoate
Without
4
38
2
64.1
0.4
10
2
11
Zr
6
43
2
n.d.
0.3
8
08-P, the reaction rate decreased notably up to 4.2 mM/h (Table
. Entry 3). The lower activity could be explained by the different
2
12
0.003
acid-base properties of the metal clusters. The impact of the
framework in the benzamide esterification with Zr-UiO-66 and
Zr-MOF-801 as catalysts was also studied. The initial rates when
using these catalysts were 10.7 and 2.2 mM/h, (Table 2. Entry 5
and 7) respectively (versus 62.0 mM/h for Zr-MOF-808-P). The
remarkable lower initial rates achieved with these materials
compared to Zr-MOF-808-P could be attributed to the higher
Reaction conditions: Amide 1a (0.3 mmol), catalyst (0.075 mmol, 25 mol%),
n-butanol (0.6 ml, 0.5 M), 150 °C. [a] Conversion and yield (%) have been
determined by gas chromatography, with n-dodecane as external standard at
2
4 h. TON = moles of product obtained /moles of catalyst (referred to metal
-1
content). TOF (h ) = initial rate/catalyst concentration. r
product formation. n.d.=not determined.
o
(mM/h) = initial rate for
3
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To check the behaviour of Zr-MOF-808-P as heterogeneous
catalyst, it was evaluated by hot filtration test. To do that, the
catalyst was removed from the reaction mixture by hot filtration
after 1.7 h of reaction time at 150 °C, when the product yield
reached 14 %. The reaction, once the solid was removed, was
allowed to proceed for 22 hours where the product yield was 19 %
The stability of the catalyst during the benzamide esterification
was studied by successive reutilization finding that the catalyst
could be reused for at least five consecutive cycles (Figure 3).
After the first run, the yield decreased approximately 17 %, but it
remained constant for further reuses. The recovered Zr-MOF-
1
3
808-P was characterized by PXRD, C-CP MAS NMR, ICP and
EA, FESEM, FT-IR, thermogravimetric analysis and N
2
(
Figure 2), observing a slight progress of the reaction. Leaching
of active sites to the reaction medium was analysed by ICP. It was
found 65 ppm of Zr in the post-reaction solution measured after a
first use of the catalyst (at 22 hours when the product reached
physisorption isotherms (see Supporting information, section 2.3).
13C-CP MAS NMR shows that, after the first use, the solid catalyst
has experienced the exchange of the more labile non-structural
formate linkers with benzoate ligands (Figure S24). Benzoic acid
would be formed as a result of benzamide or butylbenzoate
hydrolysis. Further, that exchange could be facilitated by the polar
solvent (n-BuOH) employed in the reaction, as has been reported
previously por Zr-MOF-808 when using methanol.54 That
structural change is also observed in the PXRD data measured in
the five-times-used catalyst, showing differences in signal
intensities and increased FWHM compared to the fresh Zr-MOF-
9
9 %). While 85 ppm of Zr (average of two experiments) were
measured in the hot filtration test experiment after 1.7 hours
reaction time. With these data, we could infer that those leached
zirconium species could account for the low catalytic activity
observed in the hot filtration test.
8
08-P. In addition, FESEM images after the first run indicate slight
changes in the morphology with the appearance of a small
amount of amorphous phase (see Supporting information, section
100
2
.3). A reduction in the total pore volume was determined from
Zr-MOF-808-P
Filtration test
the N adsorption and desorption isotherm measured in the five-
2
8
6
4
2
0
times-used catalyst. Those facts could account for the diminished
catalytic activity observed after the first use of the catalyst.
Nonetheless, the activity of the resulting catalyst was good in
successive runs allowing product formation in 80 % yield.
Such observed ligand exchange was also studied when using an
aliphatic amide (butyramide) as starting material. In a similar
manner, 13C-CP MAS NMR spectrum (Figure S25) of the
recovered Zr-MOF-808-P shows the presence of butyrate linker
in place of formate accounting for ligand exchange during the
reaction progress.
0
0
0
0
0
5
10
Time (h)
Figure 2. Kinetic study in the benzamide esterification catalyzed by Zr-MOF-
08-P together with the hot filtering test. Reaction conditions: Benzamide 1a
0.3 mmol), Zr-MOF-808-P (0.075 mmol, 25 mol%), n-butanol (0.6 ml, 0.5 M),
50 °C, n-dodecane (0.05 mmol) as external standard.
15
20
25
8
(
1
Scope of the amide esterification reaction
Since Zr-MOF-808-P exhibited remarkable activity toward amide
esterification, a wide range of substrates has been investigated to
demonstrate the general applicability of this catalytic system. The
scope has been expanded to various primary aromatic amides
substituted with different electron-donating groups on the ring,
such as methyl (3b, 3c) or methoxy group (3k, Figure 4), and also
with electron-withdrawing groups, such as trifluoromethyl (3i),
nitro (3h) or halogens (3d, 3e, 3f, Figure 4), giving in all cases
the desired products with high yields. It should be noted here that
substrates bearing bromide and even iodide groups were well
tolerated for which, in contrast, homogeneous transition-metal
catalytic systems could not be applied due to extensive
dehalogenation. Substituents in ortho positions are allowed
although in these cases the corresponding esters are obtained in
moderate yields probably due to steric hindrance (2c, 2e, Figure
Conversion (%)
Yield(%)
1
00
8
0
0
0
0
6
4
2
4
). With heteroaromatic amides, the performance of this
methodology was good (around 70-100 % yield, 2l, 2m, Figure
). Also, aliphatic amides were examined obtaining high yields
0
1
2
3
4
5
4
Run
Figure 3. Evolution of conversion and yield of benzamide solvolysis in the reuse
of the Zr-MOF-808-P catalyst.
(2p, 2q, 2t, Figure 4), albeit the performance decreases slightly
with the ramification in the alpha position on the chain (2r, 2s,
Figure 4). As conclusion, this methodology could therefore be
extended to a variety of functionalized amides.
4
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Figure 4. Evolution of conversion and yield of benzamide solvolysis in the reuse of the Zr-MOF-808-P catalyst. Scope for solvolysis of amides with n-BuOH catalyzed
a
by Zr-MOF-808-P. Reactions conditions: Amide 1a or 3 (0.1 mmol), Zr-MOF-808-P (25 mol%), n-butanol (0.2 ml, 0.5 M), 150 °C. In brackets, the yield of the product
isolated by flash chromatography (1 mmol scale). bConversion and yield (%) determined by 1H NMR using 1,3,5- trimethoxybenzene as external standard.
Figure 5. Scope for the solvolysis of amides with different alcohols. Reactions
conditions: Amide 1a (0.1 mmol), Zr-MOF-808-P (25 mol%), R’-OH (0.2 ml,
a
1
0
1
.5 M), 150 °C, 24 h. Conversion and yield (%) determined by H NMR using
,3,5- trimethoxybenzene as external standard.
Figure 6. Extension of the methodology to the esterification of amides with
alcohols in mesitylene. Reactions conditions: Amide 1a or 3p (1 mmol), Zr-MOF-
8
08-P (25 mol%), R’-OH (2 mmol, 2 eq), mesitylene (1 ml, 1 M), 150 °C, 44 h.
a
Yield (%) of the product isolated by flash chromatography.
5
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The alcohol scope was also considered in the benzamide
esterification. Various alcohols with larger chains than n-butanol
benzoate was obtained from these two amides. For
N-benzoylpyrrolidine or N-benzoylmorpholine (1b, 1c, Figure 7),
the transformation was less successful. In the case of compounds
1g and 1h, it was observed that the released amines (anilines)
form by-products (N-butylanilines) as a result of the N-alkylation
reaction with the solvent n-butanol.
(
such as n-hexanol and n-octanol) were tested in solvolitic
conditions, obtaining in all cases good conversions and yields. A
secondary alcohol, 2-pentanol, was also tested, achieving low
yield in this case. (Figure 5).
Moreover, more complex alcohols, such as benzyl alcohol, (S)-1-
phenylethanol or 4-nitrobenzyl alcohol, have been tested for
benzamide esterification in non-solvolitic conditions, with only two
equivalents of alcohol in mesitylene at 150 °C (Figure 6). In all
cases, the product yields achieved were also excellent,
approaching ~90 % for the different alcohols.
Role of acid sites in MOFs catalytic performance
Thermodynamically, in some case, the number of defects in the
material structure is related to its stability.56,57 In MOFs, which are
crystalline solids in all their infinite network, these defects could
be introduced spontaneously or in
a controlled manner,
modulating their final properties.58,52 Active sites are
coordinatively unsaturated metal centres (CUS) present in the
MOF intrinsically by design and additionally as a consequence of
defects derived from uncoordinated ligands to the metal centre.
This means that there is a direct relation between defects and
active sites.
Amide esterification can be catalyzed by acid sites (Brönsted and
Lewis)14,22,27,29 and by catalysts containing both acid and base
centres.59,19,30 Then, to identify the acidity of active sites in these
MOFs, they were exposed to CO as probe molecule and analysed
by FT-IR spectroscopy. CO has a weak basicity to be able to
discriminate between Brönsted and Lewis acid sites.60,61,62 With a
pre-treatment of both Zr-MOF-808 samples at 100 °C under high-
-1
vacuum (Figure 8. a and b), two bands (2153 and 2147 cm ) can
be observed after deconvolution. At the same time, a band at
3
675 cm-1 disappears in favour of the appearance of another
-1
(
3606 cm ). This fact evidences the presence of two different
3
Brönsted acid sites, associated with µ -OH group of metal
cluster.63,58 We also observe a band at 2138 cm-1 related to
physisorbed CO.61,62
Moreover, when these samples were pre-treated at 250 °C under
high-vacuum (Figure 8. c and d) for release of formate linkers54
and/or dehydroxylation of the cluster,56 two bands are identified at
-
1
2
155 cm , corresponding to the interaction of CO with Brönsted
-1
acid sites, and at 2177 cm , being assigned to Lewis acid centres.
This means that one of the types of Brönsted acid sites was lost
with the dehydroxylation, generating Lewis acid sites.
Figure 7. Selection of the appropriate leaving group in the amide structure with
n-butanol catalyzed by Zr-MOF-808-P. Reactions conditions: Amide
1
(
0.1 mmol), Zr-MOF-808-P (42 mol%), n-butanol (0.2 ml, 0.5 M), 150 °C, 15 h.
Yield (%) determined by gas chromatography, using n-dodecane (0.1 mmol)
2
147
2138
2153
a
a)
3675
2147
b)
2
138
3
635
2153
as external standard.
2130
3
606
2130
On the other hand, the nature of the leaving groups could be a
determinant factor for reaction viability with amides, as it has been
proposed in different literature reports.20,55 As a proof of concept,
a wide range of amides with different leaving group (non-
activated, twisted and distorsioned amides) has been selected to
study their esterification reaction using Zr-MOF-808-P as catalyst.
Primary amides (1a) were efficiently converted to butyl benzoate
2
170
3
675 3606
c)
2138
d)
2138
2155
2177
2155
2176
3
675 3606
3791
3675
3600
(
2a) (Figure 7).
This methodology could also be applied to a variety of amides,
such as N-Boc-N-methylbenzamide, N,N-dimethylbenzamide,
N-methoxy-N-methylbenzamide or N-(2-hydroxyethyl)benzamide
3
900 3700
2200 2150
3900 3700
2200 2150 2100
-
1
Wavenumber (cm )
Figure 8. Difference FT-IR spectra for CO adsorption of a) Zr-MOF-808-P and
b) Zr-MOF-808 pre-treated at 100 °C; c) Zr-MOF-808-P and d) Zr-MOF-808 pre-
treated at 250 °C.
(
with an alternative mechanism via N,O-rearrangement)18,19 (1d,
1
e, 1f, 1j, Figure 7), with moderated conversion. Further, during
the reaction, the thermal deprotection of N-Boc-N-methyl-
benzamide generating N-methylbenzamide happened. So, butyl
6
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Then, Hf-MOF-808-P (with a pre-treatment at 250 ºC) was studied
ꢁꢂꢃꢄꢅꢅꢆꢇ
[
푃ℎ퐶푂푁퐻 ][퐵푢푂퐻]
2
(
see SI, Section 2.2.3). For Hf-MOF-808-P, the relative intensity
=
ꢈꢃ푒푡
ꢉ
ꢍ
(ꢊ + ꢈꢋ[푃ℎ퐶푂푁퐻2] + ꢈ2[퐵푢푂퐻] + ꢈꢌ[푃ℎ퐶푂푂퐵푢])2
-1
of the signals centered at 2171 and 2153 cm , related to the
Lewis and Brönsted acid sites respectively are lower than for
Zr-MOF-808.
The kinetic equation was solved with the initial rate method. The
initial rate was analysed considering three variables (amount of
benzamide, n-butanol or butyl benzoate) and maintaining the
other parameters constant (see SI, section 3.3). The linearization
for each case offered an equations system, where the adsorption
constants could be calculated (see Supporting Information,
Finally, Zr-UiO-66 (with a pre-treatment at 200 ºC) was analysed.
-1
The Brönsted acid sites (at 2153 cm ) are the mostly presented
in this sample (see SI, section 2.2.3).
On the hypothesis that the intensity in the CO adsorption is
proportional to the concentration of acid sites, the integrals of the
section 3.3). This adsorption constants are K
1 2
(PhCONH ) = 8.53,
K
2
(BuOH) = 0.95 and K (PhCOOBu) = 24.17. n-BuOH was
3
vibration signals can be directly correlated to the number of acid
centres in the MOF.61,62 Then, the two IR bands (2155 and
weakly adsorbed on the MOF-808-P surface, explaining the need
for a higher amount of n-BuOH in the reaction media, and that
butyl benzoate was adsorbed more strongly than benzamide. The
knowledge acquired from the kinetic study has been very useful
to design the in situ FT-IR experiments, which will be studied in
the next section, when discussing the molecular reaction
mechanism.
-1
2
177 cm ) at the maximum adsorption of CO for each MOF were
deconvoluted. From these calculations, it can be concluded that
Zr-MOF-808-P possesses a relative amount of acid centres
slighty higher than Zr-MOF-808 for dehydroxylated formula
(
Table 3). Furthermore, the number of BTC linkers was
determined by TGA analysis54 (see SI, section 2.2.2) finding that
Zr-MOF-808-P presents 1.7 linkers versus 1.9 BTC linkers
detected for Zr-MOF-808 revealing a higher degree of defects for
the Zr-MOF-808-P framework.
Mechanistic studies by in situ FT-IR
The possible reaction mechanism for benzamide esterification
with n-butanol catalyzed by Zr-MOF-808-P has been investigated
by in situ FT-IR spectroscopy. Firstly, the interaction of the
benzamide with potential active sites has been studied. Figure 9
shows the FT-IR spectra of a) Zr-MOF-808-P and b) Zr-MOF-808-
P with pre-adsorbed benzamide. After the addition of benzamide,
a splitting in the band at 3677 cm-1 together with an increment of
the signal centered at 3300 cm-1 was observed, which could be
attributed to the interaction between benzamide and the hydroxyl
groups of metal cluster via intermolecular hydrogen bonding. The
Table 3. Relative amount of Lewis and Brönsted acid centres (a. u.) at the
maximum adsorption of CO (with a pre-treatment at 250 °C).
-
1
Acid
Lewis
ν (cm )
2176
Zr-MOF-808-P
0.70
Zr-MOF-808
0.68
Brönsted
2155
0.50
0.47
With regards to Hf-MOF-808-P and Zr-UiO-66 samples, a relative
lower amount of acidic centers than for Zr-MOF-808 materials
was determined (see SI, Table S3). This is in line with the
diminished catalytic performance of the former solids.
-1
bands associated with carbonyl group (~1600 cm ) of benzamide,
which would be of high utility, cannot be observed because they
fall within the metal-organic framework region. Based on the
higher zirconium oxophilicity, we propose that the most likely
interaction between the Zr cluster and benzamide can occur via
Brönsted-Lewis acid pair and the benzamide molecule, through
Kinetic study of the esterification of benzamide with
n-butanol catalyzed by Zr-MOF-808-P
the carbonyl group (Zr(MOF)···O=C(benzamide)) and the NH
group (O-H(MOF)···N-H
(benzamide)) (Figure 9).65
2
We have studied the kinetics of the benzamide esterification with
2
n-butanol, and
a
Langmuir-Hinshelwood-Hougen-Watson
(
LHHW)64 type kinetic model has been proposed to explain the
mechanism for this reaction. This model considers that there is
only one type of active site on the catalyst surface, on which
substrates can be adsorbed. On those bases, the reaction
mechanism would be as follows:
3740 3680 3620
•
Adsorption of the benzamide and n-butanol on MOF.
퐾1
3300
푃ℎ퐶푂푁퐻 + S(푀푂퐹) ↔ 푃ℎ퐶푂푁퐻 − S(푀푂퐹)
2
2
퐾ꢀ
3677
퐵푢푂퐻 + S(푀푂퐹) ↔ 퐵푢푂퐻 − 푆(푀푂퐹)
b)
a)
•
Transformation of the substrates on the catalyst.
푘푟
푃ℎ퐶푂푁퐻 − S(푀푂퐹) + 퐵푢푂퐻 − 푆(푀푂퐹) →
2
푃ℎ퐶푂푂퐵푢 − 푆(푀푂퐹)
•
Desorption of butyl benzoate.
퐾3
푃ℎ퐶푂푂퐵푢 − 푆(푀푂퐹) ↔ 푃ℎ퐶푂푂퐵푢 + S(푀푂퐹)
Then, it‘s considered that the surface reaction is the rate-
controlling step and the adsorption and desorption processes are
in equilibrium. Thus, the rate equation can be formulated as
follows:
4000
3500
3000
2500
2000
1500
1000
500
-
1
Wavenumber (cm )
Figure 9. FT-IR spectra of a) Zr-MOF-808-P and b) Zr-MOF-808-P with pre-
adsorbed benzamide.
7
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Subsequently, n-BuOH was dosed on Zr-MOF-808-P with
pre-adsorbed benzamide at room temperature. Two new signals
appeared at 1070 and 1030 cm-1 related to C-O stretching
vibration bands of n-BuOH due to the formation of Lewis pair
Zr(MOF)···O-H(n-BuOH) in the terminal and bridging node,
respectively66 (Figure 10). Furthermore, the signal at 3674 cm-1
associated with hydroxyl groups of metal cluster disappeared in
favour of the increment of a new band centered at 3000 cm-1
which can be attributed to the hydrogen bond interaction between
O(MOF)···H-O(n-BuOH) (see Supplementary Information,
section 3.4).
Scheme 3. Butoxide formation on Zr-MOF-808.
In a different set of experiments, the IR cell was then heated up
from 50 to 100 and 150 °C sequentially, allowing the reaction for
Based on the results of the in situ FT-IR study and related
4
5 minutes at each temperature. In the resulting FT-IR spectra
precedents,69,66,31 a plausible reaction mechanism has been
(
Figure 10), a decreasing in the signal centered at 1070 cm-1
proposed (Scheme 4): (1) Benzamide interacts with Zr-MOF-
together with the formation of a new band at 1146 cm-1 were
observed. Further increment of the latter band is observed when
the sample was heated up at 150 °C which may indicate formation
of butoxide species, preferably in the terminal positions of metal
cluster (Scheme 3).67,68,66 These species are more active for a
nucleophilic attack than n-butanol, favouring the amide
esterification.
8
08-P through both, the Lewis acid sites (by binding between the
coordinately unsaturated zirconia centres and the amide
carbonyl) and the Brönsted acid centres (by forming hydrogen
bonds between the hydroxyl groups of the solid and the nitrogen
of the amide) (Intermediate A). (2) n-Butanol is anchored to the
Lewis acid centres by the oxygen atom. This coupling is
reinforced by the interaction between the hydrogen of the alcohol
and the basic O2- centre of the Zr-MOF-808-P (Intermediate B).
In a separate experiment, n-BuOH was dosed directly on Zr-MOF-
8
08-P (without pre-adsorbed benzamide). In a similar manner,
At 150 °C, butoxide formation is occurring (Intermediate C).
butoxide species formation was accounted upon sample heating
to 150 ºC with the observation of the appearance of the band at
(
3) Butoxide intermediate reacts with the neighbouring
benzamide to yield the product releasing NH . The final product,
3
1
146 cm-1 (see SI, section 3.4).
butyl benzoate, is desorbed liberating the active centre.
1110
1146
1030
950
1070
150 ºC
1
00 ºC
0 ºC.
5
1110
1070 1030
b) r.t;
945
saturated
with n-BuOH
a) Zr-MOF-808-P with pre-adsorbed benzamide
1200
1100
1000
900
800
Scheme 4. Proposal mechanism for the benzamide esterification with n-BuOH
-
1
catalyzed by Zr-MOF-808-P.
Wavenumber (cm )
Figure 10. FT-IR spectra in 1250-750 cm-1 range of a) Zr-MOF-808-P with
pre-adsorbed benzamide b) Zr-MOF-808-P with pre-absorbed benzamide
saturated with n-BuOH at room temperature. The temperature was increased
for the latter sample at 50 °C, 100 °C and 150 °C and FT-IR spectra recorded
and shown at the top of the graphic, respectively.
Conclusion
Zr-MOF-808-P, with hydrophobic pockets conferred by
organic ligands and hydrophilic Zr clusters, presents specific
confined spaces and active sites for amide esterification.
More interestingly, compared to other homogeneous
catalysts, Zr-MOF-808-P can activate primary, secondary
and tertiary amides and presents a wide scope in aromatic
8
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Chemistry - A European Journal
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and aliphatic functionalised amides. Moreover, the
esterification of amides is also feasible under non-solvolitic
conditions. This material shows thermal stability acting as a
heterogeneous catalyst, that can be recovered and reused
for several reaction cycles. In situ FT-IR studies and kinetic
modelling allow a better understanding of the reaction
pathway at the molecular level. This material has the
appropriated Brönsted-Lewis acid sites to activate both
reacting substrates, the amide and the alcohol.
1
2
3
4
L. Pauling, The Nature of the Chemical Bond, Ithaca, New York, Third
Edition, 1960.
N. Sewald and H.-D. Jakubke, Peptides: Chemistry and Biology, Weinheim,
Germany, Second Edition, 2002.
V. Andrushko and N. Andrushko, Stereoselective Synthesis of Drugs and
Natural Products, New Jersey, 2013.
A. Greenberg, C. M. Breneman and J. F. Liebman, The Amide Linkage:
Structural Significance in Chemistry, Biochemistry, and Materials Science,
Chichester, New York, 2000.
5
6
A. Radzicka and R. Wolfenden, J. Am. Chem. Soc., 1996, 118, 6105–6109.
R. A. R. Bryant and D. E. Hansen, J. Am. Chem. Soc., 1996, 118, 5498–
5499.
Experimental Section
7
8
9
1
R. M. Smith and D. E. Hansen, J. Am. Chem. Soc., 1998, 120, 8910–8913.
S. Weinreb and S. Nahm, Tetrahedron Lett., 1981, 22, 3815–3818.
A. J. Kiessling and C. K. McClure, Synth. Commun., 1997, 27, 923–937.
D. J. A. Schedler, A. G. Godfrey and B. Ganem, Tetrahedron Lett., 1993,
MOF synthesis. Zr-MOF-808-P,50
acid) (0.52 g, 2.5 mmol) and ZrCl (1.75 g, 7.5 mmol) were dissolved in a
3
H BTC (1,3,5-benzenetricarboxylic
4
mixture of DMF/formic acid (226 ml, 1:1; 0.011 M) in a 500 ml flat bottom
round flask, which was heated at reflux (120 °C) under magnetic stirring
for four days. The precipitate was collected by vacuum filtration and
washed three times with fresh DMF and subsequently three more times
with fresh acetone. Then, the material was heated up at 110 °C under
vacuum for two hours approximately. The final product was obtained as a
0
34, 5035–5038.
11 J. T. Spletstoser, J. M. White, A. R. Tunoori and G. I. Georg, J. Am. Chem.
Soc., 2007, 129, 3408–3419.
12
13
14
15
16
E. H. White, J. Am. Chem. Soc., 1955, 6011–6014.
white solid (0.52 g, 2.3 mmol, 92 % yield referred to ZrCl
4
).
R. F. Abdulla and R. S. Brinkmeyer, Tetrahedron, 1979, 35, 1675–1735.
A. B. Charette and P. Chua, Synlett, 1998, 163–165.
G. Li, P. Lei and M. Szostak, Org. Lett., 2018, 20, 5622− 5625.
M. Petelin, Z. Pavlica, S. Bizimoska and M. Šentjurc, Int. J. Pharm., 2004,
270, 83–91.
(
For other MOFs, see SI, section 2.1)
Esterification of amides. General procedure of amide solvolysis.
Zr-MOF-808-P (0.25 mmol, 25 mol%), amide (1 mmol) and n-butanol (2 ml,
0
.5 M) were added to a 10 ml pyrex glass tube. The reaction mixture was
1
7
8
M. Tamura, K.-I. Shimizu and A. Satsuma, Chem. Lett., 2012, 41, 1397–
left to stir vigorously at 150 °C during the corresponding time. It was then
filtered to separate the catalyst and washed thoroughly with ethyl acetate.
The solvent was then removed in a rotavapor at reduced pressure and the
reaction crude was purified by column flash chromatography using
hexane/ethyl acetate as the eluent. All products obtained within this work
have been described previously and characterization in the literature was
used for comparison. General procedure of amide esterification in
1
405.
Y. Kita, Y. Nishii, T. Higuchi and K. Mashima, Angew. Chem. Int. Ed., 2012,
1, 5723 –5726.
19 Y. Nishii, S. Akiyama, Y. Kita and K. Mashima, Synlett, 2015, 26, 1831–
834.
1
5
1
20
21
22
C. Liu and M. Szostak, Chem. A Eur. J., 2017, 23, 7157–7173.
S. Adachi, N. Kumagai and M. Shibasaki, Chem. Sci., 2017, 8, 85–90.
H. Wu, W. Guo, S. Daniel, Y. Li, C. Liu and Z. Zeng, Chem. A Eur. J., 2018,
24, 3444–3447.
mesitylene.
A
reactive mixture was prepared with Zr-MOF-808-P
0.25 mmol, 25 mol%), the amide (1 mmol), the corresponding alcohol
2 mmol) and mesitylene (1 ml, 1 M) as solvent in a 10 ml pyrex glass tube.
(
(
It was shaken vigorously at 150°C for 44 h and then filtered to separate
the catalyst, which was washed with ethyl acetate. The solvent was then
removed in a reduced pressure rotary evaporator and the crude product
was purified by column flash chromatography using hexane/ethyl acetate
as the eluent. All products obtained within this work have been described
previously and characterization in the literature was used for comparison.
23
L. Hie, N. F. Fine Nathel, T. K. Shah, E. L. Baker, X. Hong, Y. F. Yang, P.
Liu, K. N. Houk and N. K. Garg, Nature, 2015, 524, 79–83.
J. E. Dander, N. A. Weires and N. K. Garg, Org. Lett., 2016, 18, 3934–3936.
N. A. Weires, E. L. Baker and N. K. Garg, Nat. Chem., 2016, 8, 75–79.
L. Hie, E. L. Baker, S. M. Anthony, J.-N. Desrosiers, C. Senanayake and N.
K. Garg, Angew. Chemie - Int. Ed., 2016, 55, 15129–15132.
M. C. Bröhmer, S. Mundinger, S. Bräse and W. Bannwarth, Angew. Chem.
Int. Ed., 2011, 50, 6175 –6177.
24
25
26
(For other procedures about esterification of amides, see SI, section 3.2)
27
Acknowledgements
28 S. Mundinger, U. Jakob and W. Bannwarth, Chem. A Eur. J., 2014, 20,
258–1262.
1
This work was funded by the European Union through the
European Research Council (grant ERC-AdG-2014-671093,
SynCatMatch) and by the Spanish government through the
Severo Ochoa program (SEV-2016-0683). B. V.-del-A.
acknowledges a PhD fellowship from Universitat Politécnica
de Valencia and S. R.-B. acknowledges a PhD fellowship
from the Generalitat Valenciana. The Electron Microscopy
Service of the Universitat Politècnica de València is
acknowledged for their help in sample characterization.
29 S. Mundinger, U. Jakob, P. Bichovski and W. Bannwarth, J. Org. Chem.,
2012, 77, 8968–8979.
30 S. M. A. H. Siddiki, A. S. Touchy, M. Tamura and K.-I. Shimizu, RSC Adv.,
2014, 4, 35803–35807.
31 T. Kamachi, S. M. A. H. Siddiki, Y. Morita, M. N. Rashed, K. Kon, T. Toyao,
Shimizu, Ken-ichi and K. Yoshizawa, Catal. Today, 2018, 303, 256–262.
32 Y. G. Sun, X. M. Yan, F. Ding, E. J. Gao, W. Z. Zhang and F. Verpoort,
Inorg. Chem. Commun., 2008, 11, 1117–1120.
33 H. Deng, S. Grunder, K. E. Cordova, C. Valente, H. Furukawa, M. Hmadeh,
F. Gándara, A. C. Whalley, Z. Liu, S. Asahina, H. Kazumori, M. O’Keeffe,
O. Terasaki, J. F. Stoddart and O. M. Yaghi, Science (80-. )., 2012, 336,
1018–1024.
Keywords: Metal-organic frameworks • Amides •
Heterogeneous catalysis • Kinetics • Reaction mechanisms
9
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3
4
O. K. Farha, I. Eryazici, N. C. Jeong, B. G. Hauser, C. E. Wilmer, A. A.
Sarjeant, R. Q. Snurr, S. T. Nguyen, A. Ö. Yazaydin and J. T. Hupp, J. Am.
Chem. Soc., 2012, 134, 15016–15021.
Morris, J. Phys. Chem. C, 2018, 122, 14582–14589.
63 W. Zhou, Z. Ma, S. Guo, M. Wang, J. Wang, M. Xia, L. Jia, B. Hou, D. Li
and Y. Zhao, Appl. Surf. Sci., 2018, 427, 867–873.
64 Y. Liu, J. Liu, H. Yan, Z. Zhou and A. Zhou, ACS Omega, 2019, 4, 19462–
19468.
35
36
37
P. García-García, M. Müller and A. Corma, Chem. Sci., 2014, 5, 2979–
3007.
Y. H. Vo, T. V. Le, H. D. Nguyen, T. A. To, H. Q. Ha, A. T. Nguyen, A. N.
Q. Phan and N. T. S. Phan, J. Ind. Eng. Chem., 2018, 64, 107–115.
J. Baek, B. Rungtaweevoranit, X. Pei, M. Park, S. C. Fakra, Y.-S. Liu, S. A.
Alshmimri, S. Alshehri, C. A. Trickett, G. A. Somorjai and O. M. Yaghi, J.
Am. Chem. Soc., 2018, 140, 18208–18216.
65 M. Yashiro, T. Takarada, S. Miyama and M. Komiyama, J. Chem. Soc.
Chem. Commun., 1994, 2, 1757–1758.
66 K. Xuan, Y. Pu, F. Li, J. Luo, N. Zhao and F. Xiao, Chinese J. Catal., 2019,
40, 553–566.
67 K. T. Jung and A. T. Bell, J. Catal., 2001, 204, 339–341.
68 L. Chen, S. Wang, J. Zhou, Y. Shen, Y. Zhao and X. Ma, RSC Adv., 2014,
4, 30968–30975.
3
8
9
P. García-García, J. M. Moreno, U. Díaz, M. Bruix and A. Corma, Nat.
Commun., 2016, 7, 10835.
3
S. Rojas-Buzo, P. García-García and A. Corma, ChemCatChem, 2017, 9,
69 L. Desidery, S. Chaemcheun, M. Yusubov and F. Verpoort, Catal.
Commun., 2018, 104, 82–85.
997–1004.
4
0
1
M. Lammert, C. Glißmann and N. Stock, Dalt. Trans., 2017, 46, 2425–2429.
T. Islamoglu, D. Ray, P. Li, M. B. Majewski, I. Akpinar, X. Zhang, C. J.
Cramer, L. Gagliardi and O. K. Farha, Inorg. Chem., 2018, 57, 13246–
4
13251.
4
4
4
4
4
4
4
4
5
5
5
5
5
2
3
4
5
6
7
8
9
0
1
2
3
4
S. Ullah, U. Yunus, M. H. Bhatti, P. D. Southon, K. Iqbal and S. Zaidi,
ChemistrySelect, 2018, 3, 10434–10438.
B. Li, D. Chen, J. Wang, Z. Yan, L. Jiang, D. Duan, J. He, Z. Luo, J. Zhang
and F. Yuan, Sci. Rep., 2014, 4, 39–43.
S. Yuan, J. Qin, C. T. Lollar and H.-C. Zhou, ACS Cent. Sci., 2018, 4, 440–
4
50.
S. Rojas-Buzo, P. García-García and A. Corma, Green Chem., 2018, 20,
081–3091.
S. Rojas-Buzo, P. García-García and A. Corma, ChemSusChem, 2018, 11,
32–438.
3
4
H.-B. Luo, M. Wang, S.-X. Liu, C. Xue, Z.-F. Tian, Y. Zou and X.-M. Ren,
Inorg. Chem., 2017, 56, 4169–4175.
H.-Q. Zheng, C.-Y. Liu, X.-Y. Zeng, J. Chen, J. Lu, R.-G. Lin, R. Cao, Z.-J.
Lin and J.-W. Su, Inorg. Chem., 2018, 57, 9096–9104.
H. G. T. Ly, G. Fu, A. Kondinski, B. Bueken, D. De Vos and T. N. Parac-
Vogt, J. Am. Chem. Soc., 2018, 140, 6325–6335.
H. Furukawa, F. Gándara, Y.-B. Zhang, J. Jiang, W. L. Queen, M. R.
Hudson and O. M. Yaghi, J. Am. Chem. Soc., 2014, 136, 4369–4381.
J. Jiang, F. Gándara, Y.-B. Zhang, K. Na, O. M. Yaghi and W. G. Klemperer,
J. Am. Chem. Soc., 2014, 138, 12844–12847.
G. C. Shearer, S. Chavan, S. Bordiga, S. Svelle, U. Olsbye and K. P.
Lillerud, Chem. Mater., 2016, 28, 3749–3761.
G. Wißmann, A. Schaate, S. Lilienthal, I. Bremer, A. M. Schneider and P.
Behrens, Microporous Mesoporous Mater., 2012, 152, 64–70.
C. Jia, F. G. Cirujano, B. Bueken, B. Claes, D. Jonckheere, K. M. Van
Geem and D. De Vos, ChemSusChem, 2019, 101, 1256–1266.
J. Aubé, Angew. Chem. Int. Ed., 2012, 51, 3063–3065.
5
5
6
5
Y. Bai, Y. Dou, L. Xie, W. Rutledge, J. Li and H. Zhou, Chem. Soc. Rev.,
2016, 45, 2327–2367.
5
7
8
T. Devic and C. Serre, Chem. Soc. Rev., 2014, 43, 6097–6115.
H.-H. Mautschke, F. Drache, I. Senkovska, S. Kaskel and F. X. Llabrés i
Xamena, Catal. Sci. Technol., 2018, 8, 3610–3616.
5
59
60
61
62
Y. Bourne-Branchu, C. Gosmini and G. Danoun, Chem. A Eur. J., 2017, 23,
1
0043–10047.
C. Morterra, G. Cerrato and S. Di Ciero, Appl. Surf. Sci., 1998, 126, 107–
28.
V. L. Sushkevich, A. Vimont, A. Travert and I. I. Ivanova, J. Phys. Chem. C,
015, 119, 17633–17639.
D. M. Driscoll, D. Troya, P. M. Usov, A. J. Maynes, A. J. Morris and J. R.
1
2
1
0
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Chemistry - A European Journal
10.1002/chem.202003752
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Zr-MOF-808-P is shown as an efficient reusable heterogeneous catalyst for amide esterification with ample substrate scope.
Reaction mechanism is studied by in situ FTIR spectroscopy
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This article is protected by copyright. All rights reserved.