Dual-Metal N-Heterocyclic Carbene Complex (M = Au and Pd)-Functionalized UiO-67 MOF for Alkyne Hydration-Suzuki Coupling Tandem Reaction

Article abstract of DOI:10.1021/acs.joc.0c02641

Metal N-heterocyclic carbene complexes (NHC-M) have been recognized as an important class of organometallic catalysts. Herein, we demonstrate that different NHC-M (M = Au and Pd) species can be simultaneously introduced into a single metal organic framework (MOF) by direct assembly of NHC-M-decorated ligands and metal ions under solvothermal conditions. The obtained UiO-67-Au/Pd-NHBC MOF with different organometallic NHC-M species can be a highly reusable dual catalyst to sequentially promote alkyne hydration-Suzuki coupling reaction. The potential utility of this strategy is highlighted by the preparation of many more new multicatalysts of this type for various organic transformations in a sequential way.

Full text of DOI:10.1021/acs.joc.0c02641

pubs.acs.org/joc
Article
Dual-Metal N‑Heterocyclic Carbene Complex (M = Au and Pd)-
Functionalized UiO-67 MOF for Alkyne Hydration−Suzuki Coupling
Tandem Reaction
Ying Dong,* Wen-Han Li, and Yu-Bin Dong*
Cite This: J. Org. Chem. 2021, 86, 1818−1826
Read Online
sı
*
Metrics & More
Article Recommendations
Supporting Information
ACCESS
ABSTRACT: Metal N-heterocyclic carbene complexes (NHC-M) have been
recognized as an important class of organometallic catalysts. Herein, we
demonstrate that different NHC-M (M = Au and Pd) species can be
simultaneously introduced into a single metal organic framework (MOF) by
direct assembly of NHC-M-decorated ligands and metal ions under
solvothermal conditions. The obtained UiO-67-Au/Pd-NHBC MOF with
different organometallic NHC-M species can be a highly reusable dual catalyst
to sequentially promote alkyne hydration−Suzuki coupling reaction. The
potential utility of this strategy is highlighted by the preparation of many more
new multicatalysts of this type for various organic transformations in a
sequential way.
can be directly combined to generate MOFs under synthetic
conditions. Similarly, we envision that the different types of
metal catalyst-loaded ligands with the same coordinating
functionality could also be simultaneously introduced into a
single MOF framework. This one-pot mixed-ligand assembly
would not only allow the interdisciplinary catalytic species to be
joined in a single catalytic platform but could display different
activation modes to achieve new reactivity not accessible with a
single catalyst.
Since Arduengo et al. reported the first example of stable N-
heterocyclic carbene (NHC) species,7 the molecular NHC−
metal complexes (NHC-M), as an important class of organo-
metallic catalysts, have drawn more and more attention because
of their special electronic characteristics.8 So far, as we know,
there are three synthetic methods for introducing catalytically
active NHC-M into MOFs.9 The first way is the formation of
NHC-M species in MOFs via one-pot in situ approach. The
second way is to construct such MOFs using presynthesized
NHC-M ligands. The third way is to embed NHC-M catalytic
sites on the established MOFs. The NHC-M-containing MOFs
have been demonstrated to be a highly active class of
heterogeneous organometallic catalysts in Suzuki−Miyaura,
INTRODUCTION
■
Different from the monocatalytic system, a multicatalytic
system, which involves two independent catalysts to work in
series without interfering with one another, can promote two or
more distinctive chemical reactions in one pot.1 In this field, the
cooperation between molecular transition-metal catalysts and
organocatalysts has been the main theme,2 while the multi-
catalytic system based on the two different transition-metal
catalysts has limitations and room for improvement.3 This might
be caused by the inherent difficulty of ensuring redox
compatibility between the different transition-metal catalysts.4
On the other hand, the conventional transition metal-based
multicatalytic systems, often referred to as precious metal
species, are usually capable of single use in homogeneous
catalysis. Owing to the increasing environmental issues and need
for sustainable development, one of the important research aims
of chemists is to develop the green and facile organic synthetic
reactions. For meeting the multifaceted requirements of low-
cost, resource-saving, and ecofriendly catalytic synthesis, the
development of heterogeneous dual transition-metal catalysts is
highly desired.
Metal organic frameworks (MOFs),5 in which the metal ions
and organic ligands arrange alternatively to form porous
networks, provide a unique opportunity to access transition
metal-based heterogeneous catalysts. One hand, MOFs
themselves are inherent heterogeneous catalysts because of
their metal−organic hybrid and polymeric natures; on the other
hand, the scope of MOF catalysts can be largely broadened
through the employment of a ligand premodification strategy,6
by which the catalyst-decorated organic ligands and metal ions
Received: November 5, 2020
Published: December 28, 2020
https://dx.doi.org/10.1021/acs.joc.0c02641
© 2020 American Chemical Society
J. Org. Chem. 2021, 86, 1818−1826
1818

The Journal of Organic Chemistry
pubs.acs.org/joc
Article
Scheme 1. Synthesis of Au-NHBC-H2L, Pd-NHBC-H2L, and UiO-67-Au/Pd-NHBC
Figure 1. (a) SEM image of UiO-67-Au/Pd-NHBC. (b) DLS measurement. (c) PXRD patterns of UiO-67 and UiO-67-Au/Pd-NHBC. (d,e) XPS
spectra of UiO-67-Au/Pd-NHBC. (f) N2 adsorption isotherms of UiO-67 and UiO-67-Au/Pd-NHBC at 77 K. The pore distribution for UiO-67-Au/
Pd-NHBC was inserted.
Mizoroki−Heck cross-coupling reactions, the hydrogenation of
olefins, and the reduction of nitrobenzene.9 By introducing the
different NHC-M-decorated ligands into a single MOF
framework, we imagine the MOF-catalysts with dual catalytic
behaviors could be realized via one-pot assembly. To our
knowledge, the synthesis of the heterogeneous dual catalysts of
NHC-M/M′-MOF in this way has never been reported thus far.
RESULTS AND DISCUSSION
We report herein, for the first time, a gold and palladium N-
heterocyclic bis-carbenes (Au-NHBC and Pd-NHBC) doped
■
1819
https://dx.doi.org/10.1021/acs.joc.0c02641
J. Org. Chem. 2021, 86, 1818−1826

The Journal of Organic Chemistry
pubs.acs.org/joc
Article
a
Table 1. Optimization of the Model Alkyne Hydration−Suzuki Coupling One-Pot Reaction
b
entry
mol % Au, mol % Pd
solv.
base, T (°C), t (i + ii)
conv. 1a (yield, 4a)
1
2
3
4
5
6
7
8
9
0.5 mol % Au, 0.26 mol % Pd
0.5 mol % Au, 0.26 mol % Pd
0.5 mol % Au, 0.26 mol % Pd
0.5 mol % Au, 0.26 mol % Pd
0.5 mol % Au, 0.26 mol % Pd
0.5 mol % Au, 0.26 mol % Pd
0.5 mol % Au, 0.26 mol % Pd
0.5 mol % Au, 0.26 mol % Pd
0.5 mol % Au, 0.26 mol % Pd
0.3 mol % Au, 0.16 mol % Pd
0.5 mol % Au, 0.26 mol % Pd
0.5 mol % Au, 0.26 mol % Pd
0.5 mol % Au, 0.26 mol % Pd
0.5 mol % Au, 0.26 mol % Pd
0.6 mol % Au, 1.12 mol % Pd
0.5 mol % Au, 0.26 mol % Pd
MeOH/H2O (1:1)
MeOH/H2O (1:3)
H2O
Et3N, 100, 24 h + 8 h
Et3N, 100, 24 h + 8 h
Et3N, 100, 24 h + 8 h
Et3N, 100, 24 h + 8 h
Et3N, 100, 24 h + 8 h
Et3N, 100, 24 h + 8 h
Et3N, 100, 24 h + 8 h
Et3N, 50, 24 h + 8 h
Et3N, 80, 24 h + 8 h
Et3N, 100, 24 h + 8 h
Et3N, 100, 18 h + 8 h
Et3N, 100, 24 h + 4 h
K2CO3, 100, 24 h + 8 h
Na2CO3, 100, 24 h + 8 h
Et3N, 100, 24 h + 8 h
Et3N, 100, 24 h + 8 h
78% (76%)
47% (45%)
25% (23%)
80% (79%)
99% (99%)
55% (52%)
82% (79%)
31% (27%)
80% (79%)
78% (76%)
90% (88%)
99% (86%)
99% (94%)
98% (90%)
99% (99%)
99% (99%)
MeOH
MeOH/H2O (3:1)
CH3CN/H2O (3:1)
1,4-dioxane/H2O (3:1)
MeOH/H2O (3:1)
MeOH/H2O (3:1)
MeOH/H2O (3:1)
MeOH/H2O (3:1)
MeOH/H2O (3:1)
MeOH/H2O (3:1)
MeOH/H2O (3:1)
MeOH/H2O (3:1)
MeOH/H2O (3:1)
c
10
11
12
13
14
15
16
d
e
a
Reaction conditions: in N2, 4-bromophenylacetylene (1a, 1.0 mmol), solvent (4.0 mL), 22.0 mg of UiO-67-Au/Pd-NHBC (0.5 mol % Au and
b
0.26 mol % Pd equiv), phenylboronic acid (3a, 1.1 mmol), base (2.0 mmol). Conversion and yield were determined by GC (Section 2 in
Supporting Information). 13.0 mg of UiO-67-Au/Pd-NHBC (0.3 mol % Au and 0.16 mol % Pd equiv). 22.0 mg of UiO-67-Au/Pd-NHBC (Au/
Pd = 1/2) (0.6% mmol Au and 1.12% mmol Pd equiv). 2.0 mg of Pd-NHBC-Me2L and 4.3 mg of Au-NHBC-Me2L (0.5 mol % Au and 0.26 mol
c
d
e
% Pd equiv).
UiO-67-type MOF (UiO-67-Au/Pd-NHBC), which was
prepared by combination of the presynthesized gold and
palladium N-heterocyclic bis-carbene dicarboxylate ligands
Au-NHBC-H2L and Pd-NHBC-H2L with biphenyl-4,4′-
dicarboxylic acid (BPDCA) and ZrCl4 under solvothermal
conditions (Scheme 1). The obtained UiO-67-Au/Pd-NHBC
MOF, in which the Au- and Pd-NHBC organometallic catalytic
species act in synergy, can highly promote alkyne hydration-
Suzuki coupling reaction in a sequential way. In addition, this
dual catalyst is stable and can be reused at least six times without
loss in its catalytic activity under the given conditions. The
NHBC-M (M = Au and Pd)-decorated ligands Au-NHBC-H2L
and Pd-NHBC-H2L were prepared by separately combining
imidazolium double-attached biphenyl dimethyl dicarboxylate
with Au(THT)Cl (THT = tetrahydrothiophene) and Pd-
(OAc)2 via multiple synthetic steps in good yields. The
formation of Au-NHBC-H2L and Pd-NHBC-H2L were well
UiO-67-Au/Pd-NHBC was 4.54 and 1.29 wt % based on
inductively coupled plasma (ICP) analysis (Section 1 in
Supporting Information). The Zr/Au/Pd molar ratio is 1/
0.1016/0.0533, and the corresponding formula of UiO-67-Au/
Pd-NHBC was described as Zr6O4(OH)4(Au-NHBC-
L)0.61(Pd-NHBC-L)0.32(BPDCA)5.07. As shown in Figure 1d,e,
the observed palladium (Pd 3d3/2 343.37 eV, Pd 3d5/2 338.06
eV) and gold (Au 4f5/2 88.80 eV, Au 4f7/2 85.14 eV) binding
energies indicated that their oxidation states in UiO-67-Au/Pd-
NHBC are bivalent and monovalent, respectively.11 The
dispersion of Pd and Au species in the MOF matrix is uniform,
which was supported by the energy-dispersive X-ray spectrum
(EDS) (Section 1 in Supporting Information). The surface area
analysis demonstrated the porosity of UiO-67-Au/Pd-NHBC
(Figure 1f). The N2 sorption measurement (77 K) demon-
strated that the MOF porosity is maintained after Au-NHBC
and Pd-NHBC doping.
1
supported by their H NMR, 13C NMR, IR, and MS spectra
The adsorption of UiO-67-Pd/Au-NHBC is reversible, and
its surface area determined by the Brunauer−Emmett−Teller
(BET) method was 1124 m2 g−1, which is smaller than that of
UiO-67 MOF (2113 m2 g−1).8 The difference between UiO-67-
Pd/Au-NHBC and its parent UiO-67 MOF is clearly caused by
the involved larger-sized Au-NHBC and Pd-NHBC species. The
pore size calculated by nonlocal density functional theory
(NLDET) is relatively narrow and centered at 8.714 Å (Figure
1f inset), which is also less than its parent UiO-67 MOF.
As described above, two independent NHC-Au and NHC-Pd
catalytic species were integrated on a single UiO-67 MOF
platform, which was expected to be a dual catalyst to
heterogeneously promote one-pot reaction. Herein, alkyne
(Section 1 in Supporting Information).
UiO-67-Au/Pd-NHBC was prepared as off-white crystalline
solids by heating a mixture of Au-NHBC-H2L/Pd-NHBC-
H2L/BPDCA (molar ratio, 1:1:8) and ZrCl4 at 100 °C in
HOAc/DMF for 36 h in 54% yield (Scheme 1). As shown in
Figure 1a, the UiO-67-Au/Pd-NHBC MOF was obtained as
nanoscale particles with a diameter centered at ∼190 nm, which
was further evidenced by the dynamic light scattering (DLC)
analysis (Figure 1b). By comparing the PXRD pattern of UiO-
67-Au/Pd-NHBC with the pristine UiO-67 MOF,10 it can be
seen that the involved Au-NHBC and Pd-NHBC species did not
affect the crystallinity and structural integrity of UiO-67
framework (Figure 1c). The doped Pd and Au amount in
1820
https://dx.doi.org/10.1021/acs.joc.0c02641
J. Org. Chem. 2021, 86, 1818−1826

The Journal of Organic Chemistry
pubs.acs.org/joc
Article
hydration-Suzuki coupling reaction was chosen to evaluate its
activity.
2a). After each catalytic run, the solid catalyst was readily
recovered by centrifugation, washed several times with DMF
As shown in Table 1, the catalytic performance of UiO-67-
Au/Pd-NHBC was initially evaluated using 4-bromophenyla-
cetylene (1a, 1.0 mmol) with UiO-67-Au/Pd-NHBC (22.0 mg,
0.5 mol % Au and 0.26 mol % Pd equiv) in MeOH/H2O (4 mL,
1/1) at 100 °C for 24 h. After the hydration step (monitored by
GC), the generated intermediate 1-(4-bromophenyl)ethanone
(2a) was allowed to further react with phenylboronic acid (3a,
1.1 mmol) with Et3N (2.0 mmol) for additional 8 h (monitored
by GC) to afford desired product 4a in 76% yield (Table 1, entry
1). The increased water ratio, for example, MeOH/H2O = 1:3 or
pure water, however, provided 4a in modest 45 and 23% yields
(Table 1, entries 2 and 3). If the reaction was carried out in pure
MeOH, 79% of product 4a was obtained (Table 1, entry 4). GC
analysis indicated that switching the solvent ratio delivered
intermediate 2a in a decreased yield, but the generated 2a could
be quantitatively transformed into 4a under the given
conditions. Therefore, the first alkyne hydration step is more
sensitive to the MeOH/H2O ratio.
The best result was observed when the reaction was
performed in MeOH/H2O with a volume ratio of 3/1 to give
the product 4a in 99% yield (Table 1, entry 5). However, when
methanol was replaced with CH3CN and 1,4-dioxane, the yields
of 4a were significantly reduced (Table 1, entries 6 and 7). In
addition, the temperature appeared to be crucial to the alkyne
hydration reaction. For example, the lower reaction temper-
atures such as 50 and 80 °C gave 4a in only 27 and 79% yields
with the proportionally unreacted 1a (Table 1, entries 8 and 9).
In addition, when the reaction was carried out with a lower
catalyst loading, 13.0 mg (0.3 mol % Au and 0.16 mol % Pd
equiv) instead of 22.0 mg of UiO-67-Au/Pd-NHBC, the
product 4a was generated in lower 76% yield, which resulted
from the lower conversion of 1a in the first alkyne hydration step
(Table 1, entry 10). Furthermore, the control experiments
indicated that the shorter reaction time would also lead to
somewhat lower yields of 2a and 4a under the given conditions
(Table 1, entries 11 and 12). Other kinds of bases, such as
K2CO3 and Na2CO3, instead of Et3N, also afford product 4a in
slightly lower 94 and 90% yields (Table 1, entries 13 and 14).
Besides, UiO-67-Au/Pd-NHBC, with a Au/Pd molar ratio of
1:2, was also used to perform the model reaction under the
optimized conditions (Table 1, entry 15), and it displayed the
same catalytic activity as that of UiO-67-Au/Pd-NHBC with a
Au/Pd molar ratio of 2:1 (Section 2 in Supporting Information).
In addition, the one-pot alkyne hydration-Suzuki coupling
reaction was also conducted using a mixture of 2.0 mg of Pd-
NHBC-Me2L (0.26% mmol Pd) and 4.3 mg of Au-NHBC-
Me2L (0.5% mmol Au), and the result indicated that the Pd-
NHBC-Me2L/Au-NHBC-Me2L mixture displayed the same
catalytic activity as 22 mg of UiO-67-Au/Pd-NHBC, but it
promoted the one-pot reaction in a homogeneous way (Table 1,
entry 16) (Section 2 in Supporting Information).
Figure 2. (a) Reusability test of UiO-67-Au/Pd-NHBC for alkyne
hydration−Suzuki coupling one-pot reaction. (b) PXRD patterns of the
as-synthesized UiO-67-Au/Pd-NHBC after six catalytic runs.
and CHCl3, dried at 100 °C for 24 h, and then was reused for the
next run under the same conditions. After six catalytic cycles, the
GC yield was still up to 93%. The measured PXRD pattern
(Figure 2b), SEM images, and SEM−EDX spectra indicated that
the structural integrity, crystallinity, morphology, and uniform
element distribution of UiO-67-Au/Pd-NHBC were well
maintained after multiple catalytic runs (Section 4 in Supporting
Information). Besides, no valence change for both Au and Pd
species were detected based on XPS spectra (Section 4 in
Supporting Information). On the other hand, basically no Au
and Pd species leaching occurred after six catalytic cycles (Au
4.49 wt %, Pd 1.21 wt %, based on ICP, Section 4 in Supporting
Information), which clearly resulted from the stable Au-C and
Pd-C bonds.
After optimization of the reaction conditions, we next
investigated the scope of this dual-catalytic one-pot reaction.
As shown in Table 2, UiO-67-Au/Pd-NHBC was tolerant to a
wide range of functional groups, and the reactions proceeded
efficiently with different position-substituted bromophenylace-
tylenes and various kinds of phenylboronic acids. For example,
the reactions of 4-bromophenylacetylene and phenylboronic
acids with both electron-donating and electron-withdrawing
groups gave products 4a−f in 96−99% yields (Table 2, entries
1−6). Compared with 4-bromophenylacetylene, 3-bromophe-
nylacetylene is less reactive and delivered the product 4g−l in
slightly lower 94−97% yields under the same conditions (Table
2, entries 7−12). 2-Bromophenylacetylene showed a compara-
ble reactivity to 3-bromophenylacetylene in the reaction of it
with phenylboronic acid and produced 4m in 97% yield (Table
2, entry 13). However, the reaction of 2-bromophenylacetylene
with substituted phenylboronic acids afforded the correspond-
ing products 4n−p in relatively lower 90−95% yields (Table 2,
As shown above, the loaded Au-NHBC and Pd-NHBC were
operating in series; the first Au-NHBC active 1a resulted in the
formation of the hydration intermediate 2a, which was further
transformed in the next catalytic cycle with the aid of the second
Pd-NHBC catalytic species in the presence of additional
substrate 3a, and afforded the final product 4a. This Au- and
Pd-catalyzed stepwise process was further verified by control
experiments (Section 3 in Supporting Information).
To prove its heterogeneous catalytic properties, the
recyclability of UiO-67-Au/Pd-NHBC was examined (Figure
1821
https://dx.doi.org/10.1021/acs.joc.0c02641
J. Org. Chem. 2021, 86, 1818−1826

The Journal of Organic Chemistry
pubs.acs.org/joc
Article
a
Table 2. Scope of UiO-67-Au/Pd-NHBC Catalyzed One-Pot Alkyne Hydration-Suzuki Coupling Reactions
a
Reaction conditions: 1 (1.0 mmol), MeOH/H2O = 3:1 (4.0 mL), UiO-67-Au/Pd-NHBC (22.0 mg, 0.5 mol % Au and 0.26 mol % Pd equiv), 100
b
°C, 24 h, in N2, 3 (1.1 mmol), Et3N (2.0 mmol), 8 h. Isolated yield.
Scheme 2. Proposed Mechanism of Alkyne Hydration−Suzuki Tandem Coupling Reaction
entries 14−16), which might result from the sterically hindered
effect. 3-fluoro-4-bromophenylacetylene was also used as a
substrate under the optimized conditions (Table 2, entry 17).
The product of 3-fluoro-4-phenylacetophenone (4q) was
obtained in 81% isolated yield. In addition, 4-chlorophenylace-
tylene, instead of 4-bromophenylacetylene, was used to perform
the reaction under the optimized conditions. The results showed
that the 4-chloroacetophenone and the desired product of 4a
were obtained in 91 and 9% yields, respectively (Table 2, entry
18), implying that 4-chloroacetophenone is much less active for
the second Pd-catalyzed coupling reaction.
On the other hand, the activity of aliphatic substrates such as
1-(bromomethyl)-4-ethynylbenzene was tested under opti-
mized conditions. The results showed that most of the substrate
was converted to 4-bromomethylacetophenone. The second Pd-
1822
https://dx.doi.org/10.1021/acs.joc.0c02641
J. Org. Chem. 2021, 86, 1818−1826

The Journal of Organic Chemistry
pubs.acs.org/joc
Article
Synthesis of Au-NHBC-H2L. In N2, a mixture of Au-NHBC-Me2L
(0.735 g, 1.0 mmol) and LiOH·H2O (0.17 g, 4.0 mmol) in CH3OH
(3.0 mL) and H2O (3.0 mL) was stirred at room temperature for 3 h.
After the removal of the solvent, the resulting aqueous solution was
acidified with diluted aqueous HBr solution (pH 2−3). The resulting
white precipitate was washed with H2O (3 × 5 mL) and MeOH (2 × 5
mL). Then, the obtained white solids and NaSbF6 (1.032 g, 4 mmol) in
CH3OH (2.0 mL) and H2O (6.0 mL) were stirred at room temperature
for additional 3 h. The resulting white precipitate was completely
catalyzed Suzuki coupling reaction, however, was not efficient
(Table 2, entry 19).
As shown in Scheme 2, the mechanism of UiO-67-Au/Pd-
NHBC-catalyzed alkyne hydration−Suzuki coupling reaction
based on 1a was supposed to include two independent catalytic
cycles. For the first Au-catalyzed alkyne hydration cycle, the Au-
NHBC species in the MOF first forms a π-complex with
brominated phenylacetylene. This step is followed by the
addition of water with concomitant release of a proton to
produce σ-bonded enol. Upon tautomerization, the resulting p-
Br−C6H4COCH2−Au(I)-NHBC ketone complex releases 2a
by reductive elimination and regenerates the catalytically active
Au(I)-NHBC species.12 In the second Pd-catalyzed Suzuki
coupling cycle, the reaction on in situ-generated bromoaceto-
phenone goes through an Pd-NHBC species-involved oxidative
addition, transmetalation with 3a, and reductive elimination
processes to access final product 4a, which is believed to be the
same as that of reported Pd-catalyzed Suzuki coupling reaction
(Section 5 in Supporting Information).
In summary, we have successfully synthesized a heterometal
N-heterocyclic bis-carbene-decorated MOF via direct assembly
of metal N-heterocyclic bis-carbene ligands with Zr(IV) ions
under solvothermal conditions. The obtained Au-NHBC- and
Pd-NHBC-doped UiO-67 MOF can be a highly heterogeneous
dual catalyst to promote alkyne hydration−Suzuki coupling
tandem reaction, which is not easily accessible with a single
catalyst. We believe that our synthetic strategy provided herein is
general; moreover, it significantly broadens the scope of MOF
catalysts. Further research of the synthesis of heterometal N-
heterocyclic bis-carbene-involved MOFs and their dual catalytic
application by this strategy is currently being undertaken in our
laboratory.
−
washed with water to remove excess SbF6 and dried at room
temperature to afford Au-NHBC-H2L (0.647 g, 75%). The yield of Au-
NHBC-H2L from compound A is 61%. 1H NMR (400 MHz, DMSO-
d6): δ 13.25 (s, 1H), 8.04 (s, 1H), 7.96 (s, 1H), 7.81 (s, 1H), 7.56 (s,
1H), 7.45 (s, 1H), 5.40 (d, J = 14.8 Hz, 1H), 5.14 (d, J = 15.1 Hz, 1H),
3.77 (s, 3H). 13C{1H} NMR (100 MHz, DMSO-d6): δ 184.5, 167.1,
141.3, 137.3, 132.2, 131.6, 129.8, 128.3, 124.6, 123.2, 50.4, 38.0. IR
(KBr, cm−1): 3420 (s), 3157 (s), 1701 (vs), 1610 (m), 1243 (s), 1193
(w), 844 (s), 768 (w). Anal. Calcd for C24H22AuF6N4O4Sb: C, 33.40;
H, 2.57; F, 13.21; N, 6.49. Found: C, 33.32; H, 2.50; F, 13.12; N, 6.63.
Au and Sb wt % were determined using ICP: calculated 22.82 and
14.11%, measured 22.96 and 14.04%, respectively. ESI-MS: calcd for
C24H22N4O4Au+ [M]+, m/z 627.1301; found, m/z 627.1299.
Synthesis of Pd-NHBC-Me2L. This compound was prepared as
slightly yellow crystalline solids (0.61 g, 83%) according to our reported
method.6d 1H NMR (400 Hz, DMSO-d6): δ 7.90 (d, J = 8.0 Hz, 2H),
7.78 (s, 2H), 7.76 (s, 2H), 7.41 (d, J = 8.0 Hz, 2H), 7.32 (s, 2H), 5.76
(d, J = 16.0 Hz, 2H), 5.24 (d, J = 16.0 Hz, 2H), 3.83 (s, 6H), 3.75 (s,
6H). 13C{1H} NMR (100 MHz, DMSO-d6), δ (ppm): 170.9, 166.3,
142.8, 137.6, 131.71, 130.5, 129.7, 127.6, 123.9, 122.5, 52.6, 50.2, 37.3.
IR (KBr, cm−1): 3420 (s), 1717 (vs), 1436 (s), 1297 (s), 1114 (m), 768
(w).
Synthesis of Pd-NHBC-H2L. This compound was prepared as yellow
crystalline solids (0.32 g, 77%) according to our reported method.6d
The yield of Pd-NHBC-H2L from compound A is 64%. 1H NMR (400
MHz, DMSO-d6), δ (ppm): 13.08 (s, 2H), 7.89 (d, J = 4.0 Hz, 2H),
7.74 (d, J = 12.0 Hz, 4H), 7.33 (d, J = 8.0 Hz, 2H), 7.29 (s, 2H), 5.77 (d,
J = 15.2 Hz, 2H), 5.23 (d, J = 15.2 Hz, 2H), 3.73 (s, 6H). 13C{1H} NMR
(100 MHz, DMSO-d6), δ (ppm): 170.9, 167.4, 142.6, 137.5, 131.4,
130.9, 130.7, 127.7, 123.9, 122.3, 50.3, 37.6. IR (KBr, cm−1): 3449 (s),
3135 (s), 1673 (vs), 1610 (m), 1457 (m), 1242 (s), 1123 (w), 698 (w).
Anal. Calcd for C24H22Br2N4O4Pd: C, 41.38; H, 3.18; Br, 22.94; N,
8.04. Found: C, 41.30; H, 3.35; Br, 22.86; N, 7.91. Pd wt % was
determined using ICP: calculated 15.28%, measured 15.75%. ESI-MS:
calcd for C24H23N4Br2O4Pd+ [M + H]+, m/z 694.9115; found, m/z
694.9126.
Synthesis of UiO-67-Au/Pd-NHBC (Au/Pd = 1/1). A mixture of
ZrCl4 (70.0 mg, 0.3 mmol), Pd-NHBC-H2L (20.8 mg, 0.03 mmol), Au-
NHBC-H2L (26.73 mg, 0.03 mmol), and 4,4-diphthalic acid (58.34 mg,
0.24 mmol) in DMF (10 mL) was sonicated for around 15 min and then
placed in a preheated 100 °C oven for 36 h. After centrifugation, the
obtained white powders were washed with DMF, then dispersed in
fresh DMF, and soaked overnight. After that, the as-synthesized sample
was immersed in chloroform at room temperature for 2 days. The
chloroform was exchanged every 12 h during this process. Then, the
sample was collected by centrifugation and dried at room temperature
in vacuum to afford the activated UiO-67-Au/Pd-NHBC as off-white
solids in 54% yield. IR (KBr, cm−1): 3386 (s), 1596 (m), 1541 (w),
1 4 0 8 ( v s ) , 7 6 1 ( w ) , 6 7 0 ( w ) . A n a l . C a l c d f o r
[Zr6O4(OH)4C93.3H59.16Br0.64N3.72O24Pd0.32Au0.61Sb0.61F3.66]: C,
42.37; H, 2.41; Br, 1.93; F, 2.63; N, 1.97; Au, 4.54; Pd, 1.29; Zr,
20.69; Sb, 2.81. Found: C, 42.18; H, 2.53; Br, 1.80; F, 2.67; N, 2.03. Au,
Pd, Zr and Sb wt % contents in UiO-67-Au/Pd-NHBC were
determined to be 4.54, 1.29, 20.69 and 2.89 wt %, respectively.
In addition, UiO-67-Au/Pd-NHBC was also synthesized with a
molar ratio of Au/Pd = 1:2 under the same synthetic conditions. The
measured PXRD pattern indicated that the obtained MOF possesses
the same structure as that of Au/Pd molar ratio 2:1 (Supporting
Information).
EXPERIMENTAL SECTION
■
All chemicals and solvents were at least of the analytic grade and
employed as received without further purification. Powder X-ray
diffraction (PXRD) measurements were conducted on a D8
ADVANCE diffractometer (Cu Kα, λ = 1.5406 Å) at 293 K. MS
analysis was performed on a Bruker maxis ultrahigh-resolution TOF MS
system. NMR data were collected using an AM-400 spectrometer.
Infrared spectra were obtained in the 400−4000 cm−1 range using a
Bruker ALPHA FT-IR spectrometer. The scanning electron micros-
copy (SEM) micrographs were recorded on a Gemini Zeiss Supra TM
scanning electron microscope equipped with energy-dispersive X-ray
(EDX) detector. XPS spectra were generated from PHI Versaprobe II.
ICP analysis was performed on an IRIS InterpidII XSP and NU AttoM.
Elemental analysis was performed on a PerkinElmer model 2400
analyzer. The total surface area of the catalyst was measured by the BET
method using N2 adsorption at 77 K; this was done by the
Micromeritics ASAP 2000 sorption/desorption analyzer.
Synthesis of Au-NHBC-H2L, Pd-NHBC-H2L, and UiO-67-Au/
Pd-NHBC. Synthesis of Au-NHBC-Me2L. In N2, a mixture of
compound A (0.186 g, 0.3 mmol), Au(THT)Cl (0.096 g, 0.3 mmol),
DMF (7 mL), and NaOAc (0.615 g, 0.75 mmol) was stirred at 120 °C
in an oil bath for 3 h. Then, the mixture was added dropwise to a
mixture of Et2O/CH2Cl2 (4:1/v/v) under vigorous stirring. The
resulting precipitate was filtered, washed with Et2O (10 mL), and dried
at room temperature to give Au-NHBC-Me2L as white powder solids
(0.168 g, 81%). 1H NMR (400 MHz, DMSO-d6): δ 8.06 (s, 1H), 7.97
(d, J = 13.4 Hz, 1H), 7.82 (s, 1H), 7.60 (s, 1H), 7.48 (d, J = 8.0 Hz, 1H),
5.43 (d, J = 15.4 Hz, 1H), 5.14 (d, J = 15.2 Hz, 1H), 3.86 (s, 3H), 3.77
(s, 3H). 13C{1H} NMR (100 MHz, DMSO-d6): δ 184.5, 166.0, 141.6,
137.5, 132.4, 130.5, 129.7, 128.2, 124.6, 123.2, 53.0, 50.3, 38.0. IR (KBr,
cm−1): 3414 (s), 1720 (vs), 1565 (m), 1436 (s), 1300 (s), 1117 (m),
765 (m).
Synthesis of UiO-67-Au/Pd-NHBC (Au/Pd = 1/2). A mixture of
ZrCl4 (70.0 mg, 0.3 mmol), Au-NHBC-H2L (26.73 mg, 0.03 mmol),
1823
https://dx.doi.org/10.1021/acs.joc.0c02641
J. Org. Chem. 2021, 86, 1818−1826

The Journal of Organic Chemistry
pubs.acs.org/joc
Article
Pd-NHBC-H2L (41.6 mg, 0.06 mmol), and 4,4-diphthalic acid (51.05
mg, 0.21 mmol) in DMF (10 mL) was sonicated for around 15 min and
then placed in a preheated 100 °C oven for 36 h. After centrifugation,
the obtained white powders were washed with DMF, then dispersed in
fresh DMF, and soaked overnight. Then, the as-synthesized sample was
immersed in chloroform at room temperature for 2 days. The
chloroform was exchanged every 12 h during this process. Then, the
sample was collected by centrifugation and dried in vacuum at room
temperature to afford the activated UiO-67-Au/Pd-NHBC as off-white
solids in 55% yield. IR (KBr, cm−1): 3388 (s), 1603 (m), 1545 (w),
1 4 0 8 ( v s ) , 7 6 1 ( w ) , 6 7 0 ( w ) . A n a l . C a l c d f o r
[Zr6O4(OH)4C115.39H96.72Br3.88N12.12O25.09Pd1.94Au1.09Sb1.09F6.54]: C,
37.23; H, 2.73; Br, 8.33; F, 3.34; N, 4.56; Au, 5.77; Pd, 5.55; Zr,
14.71; Sb, 3.57. Found: C, 37.28; H, 2.69; Br, 8.38; F, 3.28; N, 4.60. Au,
Pd, Zr and Sb wt % contents in UiO-67-Au/Pd-NHBC were
determined to be 5.77, 5.55, 14.71 and 3.62 wt % based on ICP
analysis, respectively.
General Catalytic Reaction Procedure for UiO-67-Au/Pd-NHBC-
Catalyzed Alkyne Hydration−Suzuki Coupling Tandem Reactions. A
mixture of 4-bromophenylacetylene (181 mg, 1.0 mmol) and 22.0 mg
of UiO-67-Au/Pd-NHBC (0.5 mol % Au and 0.26 mol % Pd equiv) in
4 mL of CH3OH/H2O (3/1) was stirred at 100 °C for 24 h in a N2
atmosphere. Then, phenylboronic acid (134 mg, 1.1 mmol) and NEt3
(279 μL, 2.0 mmol) were added, and the reaction was conducted for
additional 8 h (monitored by GC). After filtration, the mixture was
diluted with brine (10 mL) and extracted with ethyl acetate (3 × 10
mL). The organic phase was dried over anhydrous MgSO4 and
concentrated under vacuum. The residue was purified by column
chromatography on silica gel to afford the product as a white solid (194
mg, 99%).
227.1067; found, 227.1063. The crude product was purified by column
chromatography on silica gel using petroleum ether/EtOAc = 100/3 as
the eluent to afford product 4e as a white solid (221 mg, 98%).
4-(4-Fluorophenyl)acetophenone (4f). 1H NMR (CDCl3, 400
MHz): δ 8.03 (d, 2H, J = 8.0 Hz), 7.64 (d, 2H, J = 8.0 Hz), 7.58−7.61
(m, 2H), 7.14−7.18 (m, 2H), 2.64 (s, 3H). 13C{1H} NMR (100 MHz,
CDCl3): δ 197.7, 164.2, 161.8, 144.8, 136.0, 135.9, 129.0, 128.9, 127.1,
116.0, 115.8, 26.6. HRMS (ESI) m/z: [M + H]+ calcd for C14H12FO,
215.0867; found, 215.0872. The crude product was purified by column
chromatography on silica gel using petroleum ether/EtOAc = 50/1 as
the eluent to afford product 4f as a white solid (212 mg, 99%).
3-Phenylacetophenone (4g). 1H NMR (CDCl3, 400 MHz): δ 8.12
(t, 1H, J = 8.0 Hz), 7.83 (d, 1H, J = 8.0 Hz), 7.67 (d, 1H, J = 8.0 Hz),
7.53 (d, 2H, J = 8.0 Hz), 7.38−7.42 (m, 1H), 7.35−7.41 (m, 3H), 2.53
(s, 3H). 13C{1H} NMR (100 MHz, CDCl3): δ 198.0, 141.6, 140.1,
137.6, 131.7, 129.1, 129.0, 127.9, 127.3, 127.2, 126.8, 26.6. HRMS
(ESI) m/z: [M + H]+ calcd for C14H13O, 197.0961; found, 197.0958.
The crude product was purified by column chromatography on silica gel
using petroleum ether/EtOAc = 50/1 as the eluent to afford product 4g
as a yellow oil (188 mg, 96%).
3-(4-Fluorophenyl)acetophenone (4h). 1H NMR (CDCl3, 400
MHz): δ 8.08 (t, 1H, J = 8.0 Hz), 7.86 (d, 1H, J = 8.0 Hz), 7.64 (d, 1H, J
= 8.0 Hz), 7.47−7.51 (m, 2H), 7.44 (t, 1H, J = 8.0 Hz), 7.07 (t, 2H, J =
8.0 Hz), 2.58 (s, 3H). 13C{1H} NMR (100 MHz, CDCl3): δ 197.8,
164.0, 161.5, 140.5, 137.6, 136.2, 131.4, 129.1, 128.8, 128.7, 127.2,
126.5, 115.9, 115.7, 26.6. HRMS (ESI) m/z: [M + H]+ calcd for
C14H12FO, 215.0867; found, 215.0869. The crude product was purified
by column chromatography on silica gel using petroleum ether/EtOAc
= 50/1 as the eluent to afford product 4h as a colorless oil (203 mg,
95%).
4-Phenylacetophenone (4a). 1H NMR (CDCl3, 400 MHz): δ 8.04
(d, 2H, J = 8.0 Hz), 7.69 (d, 2H, J = 8.0 Hz), 7.63 (d, 2H, J = 8.0 Hz),
7.48 (t, 2H, J = 8.0 Hz), 7.38−7.42 (m, 1H), 2.64 (s, 3H). 13C{1H}
NMR (100 MHz, CDCl3): δ 197.7, 145.8, 139.9, 135.9, 129.0, 128.3,
127.3, 26.8. HRMS (ESI) m/z: [M + H]+ calcd for C14H13O, 197.0961;
found, 197.0958. The crude product was purified by column
chromatography on silica gel using petroleum ether/EtOAc = 50/1
as the eluent to afford product 4a as a white solid (194 mg, 99%).
4-(4-Cyanophenyl)acetophenone (4b). 1H NMR (CDCl3, 400
MHz) 8.00 (d, 2H, J = 8.0 Hz), 7.61−7.70 (m, 6H), 2.58 (s, 3H).
13C{1H} NMR (100 MHz, CDCl3): δ 196.6, 143.3, 142.5, 135.9, 131.7,
3-(4-Cyanophenyl)acetophenone (4i). 1H NMR (CDCl3, 400
MHz): δ 8.19 (t, 1H, J = 8.0 Hz), 8.01 (d, 1H, J = 8.0 Hz), 7.71−
7.79 (m, 5H), 7.60 (t, 1H, J = 8.0 Hz), 2.67 (s, 3H). 13C{1H} NMR
(100 MHz, CDCl3): δ 197.7, 144.6, 139.7, 137.9, 132.8, 131.7, 129.5,
128.6 127.9, 126.9, 118.7, 111.6, 26.8. HRMS (ESI) m/z: [M + H]+
calcd for C15H12NO, 222.0913; found, 222.0909. The crude product
was purified by column chromatography on silica gel using petroleum
ether/EtOAc = 50/1 as the eluent to afford product 4i as a white solid
(208 mg, 94%).
1
3-(3-Methoxyphenyl)acetophenone (4j). H NMR (CDCl3, 400
MHz): δ 8.14 (t, 1H, J = 8.0 Hz), 7.88 (d, 1H, J = 8.0 Hz), 7.72 (d, 1H, J
= 8.0 Hz), 7.46 (t, 1H, J = 8.0 Hz), 7.31 (t, 1H, J = 8.0 Hz), 7.15 (d, 1H,
J = 8.0 Hz), 7.11 (t, 1H, J = 8.0 Hz), 6.88 (dd, 1H, J = 8.0 Hz), 3.81 (s,
3H), 2.60 (s, 3H). 13C{1H} NMR (100 MHz, CDCl3): δ 198.0, 160.1,
141.6, 141.5, 137.6, 131.7, 130.0, 128.9, 127.4, 126.9, 119.5, 113.1,
113.0, 55.3, 26.6. HRMS (ESI) m/z: [M + H]+ calcd for C15H15O2,
227.1067; found, 227.1070. The crude product was purified by column
chromatography on silica gel using petroleum ether/EtOAc = 100/3 as
the eluent to afford product 4j as a yellow solid (219 mg, 97%).
3-(4-Methoxycarbonyl)acetophenone (4k). 1H NMR (CDCl3, 400
MHz): δ 8.12 (t, 1H, J = 8.0 Hz), 7.85 (d, 1H, J = 8.0 Hz), 7.71 (d, 1H, J
= 8.0 Hz), 7.52 (d, 2H, J = 8.0 Hz), 7.46 (t, 1H, J = 8.0 Hz), 6.97 (d, 2H,
J = 8.0 Hz), 3.81 (s, 3H), 2.61 (s, 3H). 13C{1H} NMR (100 MHz,
CDCl3): δ 197.8, 166.8, 144.5, 140.5, 137.7, 131.8, 130.2, 129.4, 129.2,
128.0, 127.1, 126.9, 52.19, 26.7. HRMS (ESI) m/z: [M + H]+ calcd for
C16H15O3, 255.1016; found, 255.1019. The crude product was purified
by column chromatography on silica gel using petroleum ether/EtOAc
= 50/1 as the eluent to afford product 4k as a colorless oil (244 mg,
96%).
128.1, 126.9, 126.4, 117.6, 110.9, 25.7. HRMS (ESI) m/z: [M + H]+
calcd for C15H12NO, 222.0913; found, 222.0910. The crude product
was purified by column chromatography on silica gel using petroleum
ether/EtOAc = 100/3 as the eluent to afford product 4b as a white solid
(214 mg, 97%).
4-(2-Methylphenyl)acetophenone (4c). 1H NMR (CDCl3, 400
MHz): δ 7.99 (d, 2H, J = 8.0 Hz), 7.40 (d, 2H, J = 8.0 Hz), 7.26 (m,
2H), 7.20−7.24 (m, 2H), 2.61 (s, 3H), 2.25 (s, 3H). 13C{1H} NMR
(100 MHz, CDCl3): δ 197.8, 147.0, 140.8, 135.6, 135.2, 130.6, 129.6,
129.5, 128.3, 128.0, 126.0, 26.8, 20.5. HRMS (ESI) m/z: [M + H]+
calcd for C15H15O, 211.1117; found, 211.1121. The crude product was
purified by column chromatography on silica gel using petroleum
ether/EtOAc = 50/1 as the eluent to afford product 4c as a yellow oil
(208 mg, 99%).
4-(4-Methoxycarbonyl)acetophenone (4d). 1H NMR (CDCl3, 400
MHz): δ 8.13 (d, 2H, J = 8.0 Hz), 8.05 (d, 2H, J = 8.0 Hz), 7.70 (t, 4H, J
= 8.0 Hz), 3.95 (s, 3H), 2.65 (s, 3H). 13C{1H} NMR (100 MHz,
CDCl3): δ 197.6, 166.9, 144.5, 144.2, 136.5, 130.24, 129.8, 129.0,
127.5, 127.3, 52.2, 26.6. HRMS (ESI) m/z: [M + H]+ calcd for
C16H15O3, 255.1016; found, 255.1014. The crude product was purified
by column chromatography on silica gel using petroleum ether/EtOAc
= 50/1 as the eluent to afford product 4d as a white solid (244 mg,
96%).
1
3-(4-Methoxyphenyl)acetophenone (4l). H NMR (CDCl3, 400
MHz): δ 8.09 (t, 1H, J = 8.0 Hz), 8.01 (d, 2H, J = 8.0 Hz), 7.86 (d, 1H, J
= 8.0 Hz), 7.70 (d, 1H, J = 8.0 Hz), 7.57 (d, 2H), J = 8.0 Hz, 7.45 (t, 1H,
J = 8.0 Hz), 3.84 (s, 3H), 2.56 (s, 3H). 13C{1H} NMR (100 MHz,
CDCl3): δ 198.2, 159.6, 141.3, 137.6, 132.6, 131.3, 129.0, 128.2, 126.6,
126.4, 114.4, 55.3, 26.8. HRMS (ESI) m/z: [M + H]+ calcd for
C15H15O2, 227.1067; found, 227.1064. The crude product was purified
by column chromatography on silica gel using petroleum ether/EtOAc
= 100/3 as the eluent to afford product 4l as a white solid (221 mg,
98%).
1
4-(3-Methoxyphenyl)acetophenone (4e). H NMR (CDCl3, 400
MHz): δ 8.02 (d, 2H, J = 8.0 Hz), 7.68 (d, 2H, J = 8.0 Hz), 7.39 (t, 1H, J
= 8.0 Hz), 7.21 (d, 1H, J = 8.0 Hz), 7.15 (m, 1H), 6.95 (dd, 1H, J = 8.0
Hz), 3.87 (s, 3H), 2.64 (s, 3H). 13C{1H} NMR (100 MHz, CDCl3): δ
197.7, 160.1, 145.7, 141.4, 136.0, 129.9, 128.8, 127.1, 119.8, 113.7,
113.1, 55.3, 26.8. HRMS (ESI) m/z: [M + H]+ calcd for C15H15O2,
1824
https://dx.doi.org/10.1021/acs.joc.0c02641
J. Org. Chem. 2021, 86, 1818−1826

The Journal of Organic Chemistry
pubs.acs.org/joc
Article
2-Phenylacetophenone (4m). 1H NMR (CDCl3, 400 MHz): δ 7.55
(dd, 1H, J = 8.0 Hz), 7.49 (dd, 1H, J = 8.0 Hz), 7.38−7.42 (m, 4H),
7.37−7.38 (m, 1H), 7.34 (d, 1H, J = 8.0 Hz), 7.33 (m, 1H), 2.00 (s,
3H). 13C{1H} NMR (100 MHz, CDCl3): δ 204.9, 140.9, 140.7, 140.5,
130.8, 130.3, 128.9, 128.7, 127.9, 127.8, 127.5, 30.7. HRMS (ESI) m/z:
[M + H]+ calcd for C14H13O, 197.0961; found, 197.0958. The crude
product was purified by column chromatography on silica gel using
petroleum ether/EtOAc = 50/1 as the eluent to afford product 4m as a
yellow solid (190 mg, 97%).
UiO-67-Au/Pd-NHBC; catalytic product characteriza-
tion; and catalyst hot leaching and catalytic cycles (PDF)
AUTHOR INFORMATION
■
Corresponding Authors
Ying Dong − College of Chemistry, Chemical Engineering and
Materials Science, Collaborative Innovation Center of
Functionalized Probes for Chemical Imaging in Universities of
Shandong, Key Laboratory of Molecular and Nano Probes,
Ministry of Education, Shandong Normal University, Jinan
250014, P. R. China; Email: dongyinggreat@163.com
Yu-Bin Dong − College of Chemistry, Chemical Engineering and
Materials Science, Collaborative Innovation Center of
Functionalized Probes for Chemical Imaging in Universities of
Shandong, Key Laboratory of Molecular and Nano Probes,
Ministry of Education, Shandong Normal University, Jinan
250014, P. R. China; orcid.org/0000-0002-9698-8863;
Email: yubindong@sdnu.edu.cn
1
2-(4-Methoxyphenyl)acetophenone (4n). H NMR (CDCl3, 400
MHz): δ 7.50−7.52 (m, 1H), 7.42−7.46 (m, 1H), 7.32−7.35 (m, 2H),
7.24 (d, 2H, J = 8.0 Hz), 6.93 (d, 2H, J = 8.0 Hz), 3.79 (s, 3H), 1.99 (s,
3H). 13C{1H} NMR (100 MHz, CDCl3): δ 205.0, 159.6, 140.9, 140.1,
133.0, 130.7, 130.2, 130.0, 127.8, 127.1, 114.2, 55.3, 30.4. HRMS (ESI)
m/z: [M + H]+ calcd for C15H15O2, 227.1067; found, 227.1066. The
crude product was purified by column chromatography on silica gel
using petroleum ether/EtOAc = 50/1 as the eluent to afford product 4n
as a colorless oil (206 mg, 91%).
2-(4-Cyanophenyl)acetophenone (4o). 1H NMR (CDCl3, 400
MHz): δ 7.71 (d, 2H, J = 8.0 Hz), 7.66 (d, 1H, J = 8.0 Hz), 7.55−7.59
(m, 1H), 7.48−7.52 (m, 1H), 7.43 (d, 2H, J = 8.0 Hz), 7.35 (d, 1H, J =
8.0 Hz), 2.22 (s, 3H). 13C{1H} NMR (100 MHz, CDCl3): δ 202.7,
145.9, 139.8, 139.0, 132.3, 131.3, 130.5, 129.5, 128.5, 118.7, 111.5, 30.2.
HRMS (ESI) m/z: [M + H]+ calcd for C15H12NO, 222.0913; found,
222.0915. The crude product was purified by column chromatography
on silica gel using petroleum ether/EtOAc = 50/1 as the eluent to afford
product 4o as a yellow oil (199 mg, 90%).
Author
Wen-Han Li − College of Chemistry, Chemical Engineering and
Materials Science, Collaborative Innovation Center of
Functionalized Probes for Chemical Imaging in Universities of
Shandong, Key Laboratory of Molecular and Nano Probes,
Ministry of Education, Shandong Normal University, Jinan
250014, P. R. China
1
2-(3-Methoxyphenyl)acetophenone (4p). H NMR (CDCl3, 400
MHz): δ 7.48−7.54 (m, 2H), 7.40 (t, 2H, J = 8.0 Hz), 7.32 (t, 1H, J =
8.0 Hz), 6.89−6.95 (m, 3H), 3.82 (s, 3H), 2.03 (s, 3H). 13C{1H} NMR
(100 MHz, CDCl3): δ 204.9, 159.8, 142.1, 141.0, 140.4, 130.7, 130.1,
129.7, 127.8, 127.6, 121.5, 114.3, 113.5, 55.3, 30.4. HRMS (ESI) m/z:
[M + H]+ calcd for C15H15O2, 227.1067; found, 227.1071. The crude
product was purified by column chromatography on silica gel using
petroleum ether/EtOAc = 50/1 as the eluent to afford product 4p as a
white solid (215 mg, 95%).
Complete contact information is available at:
https://pubs.acs.org/10.1021/acs.joc.0c02641
Notes
The authors declare no competing financial interest.
2-Fluoro-4-phenylacetophenone (4q). 1H NMR (CDCl3, 400
MHz): δ 8.08−8.11 (m, 1H), 7.72−7.76 (m, 1H), 7.57 (d, 2H, J = 8.0
Hz), 7.45 (t, 2H, J = 8.0 Hz), 7.35−7.39 (m, 1H), 7.19−7.24 (m, 1H),
2.70 (s, 3H). 13C{1H} NMR (100 MHz, CDCl3): δ 195.9, 139.2, 137.8,
133.2, 133.1, 129.5, 129.1, 129.0, 127.8, 127.0, 117.3, 117.0, 29.7.
HRMS (ESI) m/z: [M + H]+ calcd for C14H12FO, 215.0867; found,
215.0871. The crude product was purified by column chromatography
on silica gel using petroleum ether/EtOAc = 50/1 as the eluent to afford
product 4q as a white solid (173 mg, 81%).
ACKNOWLEDGMENTS
■
We are grateful for financial support from the NSFC (grants
21971153, 21671122, and 21802091), Shandong Provincial
Natural Science Foundation (grant ZR2018BB006), a Project of
the Shandong Province Higher Educational Science and
Technology Program (J18KA066), the Taishan Scholar’s
Construction Project, and Changjiang Scholar project of
China at SDNU.
4-Phenylacetophenone (4a, Table 2, Entry 18). 1H NMR (CDCl3,
400 MHz): δ 8.00 (d, 2H, J = 8.0 Hz), 7.65 (d, 2H, J = 8.0 Hz), 7.59−
7.60 (m, 2H), 7.44 (t, 2H, J = 8.0 Hz), 7.35−7.29 (m, 1H), 2.60 (s, 3H).
13C{1H} NMR (100 MHz, CDCl3): δ 197.7, 145.8, 139.9, 135.9, 129.0,
128.9, 128.3, 127.3, 127.2, 26.7. HRMS (ESI) m/z: [M + H]+ calcd for
C14H13O, 197.0961; found, 197.0956. The crude product was purified
by column chromatography on silica gel using petroleum ether/EtOAc
= 50/1 as the eluent to afford product 4a as a white solid (18 mg, 9%).
4-Bromomethylacetophenone (4r). 1H NMR (CDCl3, 400 MHz):
δ 7.95 (d, 2H, J = 8.0 Hz), 7.43 (d, 2H, J = 8.0 Hz), 4.52 (s, 3H), 2.61 (s,
3H). 13C{1H} NMR (100 MHz, CDCl3): δ 197.8, 143.8, 136.4, 128.5,
127.4, 74.0, 26.7. HRMS (ESI) m/z: [M + H]+ calcd for C9H10BrO,
212.9910; found, 212.9921. The crude product was purified by column
chromatography on silica gel using petroleum ether/EtOAc = 100/1 as
the eluent to afford product 4r as a colorless oil (204 mg, 96%).
REFERENCES
■
́
(1) (a) Afewerki, S.; Cordova, A. Combinations of Aminocatalysts and
Metal Catalysts: A Powerful Cooperative Approach in Selective
Organic Synthesis. Chem. Rev. 2016, 116, 13512−13570. (b) Huang,
Y.-B.; Liang, J.; Wang, X.-S.; Cao, R. Multifunctional metal-organic
framework catalysts: synergistic catalysis and tandem reactions. Chem.
Soc. Rev. 2017, 46, 126−157. (c) Yang, Q.; Xu, Q.; Jiang, H.-L. Metal-
organic frameworks meet metal nanoparticles: synergistic effect for
enhanced catalysis. Chem. Soc. Rev. 2017, 46, 4774−4808.
(2) (a) Patil, N. T. Merging Metal and N-Heterocyclic Carbene
Catalysis: On the Way to Discovering Enantioselective Organic
Transformations. Angew. Chem., Int. Ed. 2011, 50, 1759−1761.
(b) Allen, A. E.; Macmillan, D. W. C. Synergistic Catalysis: A Powerful
Synthetic Strategy for New Reaction Development. Chem. Sci. 2012, 3,
633−658. (c) Du, Z.; Shao, Z. Combining transition metal catalysis and
organocatalysis - an update. Chem. Soc. Rev. 2013, 42, 1337−1378.
(d) Chen, D.-F.; Han, Z.-Y.; Zhou, X.-L.; Gong, L.-Z. Asymmetric
Organocatalysis Combined with Metal Catalysis: Concept, Proof of
Concept, and Beyond. Acc. Chem. Res. 2014, 47, 2365−2377.
(3) (a) Lee, J. M.; Na, Y.; Han, H.; Chang, S. Cooperative Multi-
Catalyst Systems for One-Pot Organic Transformations. Chem. Soc.
Rev. 2004, 33, 302−312.
ASSOCIATED CONTENT
■
sı
* Supporting Information
The Supporting Information is available free of charge at
https://pubs.acs.org/doi/10.1021/acs.joc.0c02641.
Instruments and methods; synthesis and additional
characterization of Au- and Pd-NHBC ligands, and
1825
https://dx.doi.org/10.1021/acs.joc.0c02641
J. Org. Chem. 2021, 86, 1818−1826

The Journal of Organic Chemistry
pubs.acs.org/joc
Article
(4) Chen, Z.-S.; Huang, X.-Y.; Chen, L.-H.; Gao, J.-M.; Ji, K. Rh(II)/
Pd(0) Dual Catalysis: Regiodivergent Transformations of Alkylic
Oxonium Ylides. ACS Catal. 2017, 7, 7902−7907.
Catalysts for Hydrocarboxylation of Aryl Olefins and Alcohols. J. Am.
Chem. Soc. 2002, 124, 9692−9693. (c) Wang, W.; Zheng, A.; Zhao, P.;
Xia, C.; Li, F. Au-NHC@Porous Organic Polymers: Synthetic Control
and Its Catalytic Application in Alkyne Hydration Reactions. ACS
Catal. 2014, 4, 321−327.
(12) Ibrahim, H.; de Fremont, P.; Braunstein, P.; Thery, V.; Nauton,
L.; Cisnetti, F.; Gautier, A. Water-Soluble Gold-N-Heterocyclic
Carbene Complexes for the Catalytic Homogeneous Acid- and
Silver-Free Hydration of Hydrophilic Alkynes. Adv. Synth. Catal.
2015, 357, 3893−3900.
(5) (a) Zaera, F. Nanostructured Materials for Applications in
Heterogeneous Catalysis. Chem. Soc. Rev. 2013, 42, 2746−2762.
(b) Liu, J.; Chen, L.; Cui, H.; Zhang, J.; Zhang, L.; Su, C.-Y.
Applications of Metal-Organic Frameworks in Heterogeneous Supra-
molecular Catalysis. Chem. Soc. Rev. 2014, 43, 6011−6061. (c) Corma,
́
́
́
A.; García, H.; Llabres i Xamena, F. X. Engineering Metal Organic
Frameworks for Heterogeneous Catalysis. Chem. Rev. 2010, 110,
4606−4655. (d) Huang, Y.-B.; Liang, J.; Wang, X.-S.; Cao, R.
Multifunctional Metal-Organic Framework Catalysts: Synergistic
Catalysis and Tandem Reactions. Chem. Soc. Rev. 2017, 46, 126−157.
(e) Rogge, S. M. J.; Bavykina, A.; Hajek, J.; Garcia, H.; Olivos-Suarez, A.
́
I.; Sepulveda-Escribano, A.; Vimont, A.; Clet, G.; Bazin, P.; Kapteijn, F.;
́
Daturi, M.; Ramos-Fernandez, E. V.; Llabres i Xamena, F. X.; Van
Speybroeck, V.; Gascon, J. Metal-Organic and Covalent Organic
Frameworks as Single-Site Catalysts. Chem. Soc. Rev. 2017, 46, 3134−
3184. (f) Wang, Q.; Astruc, D. State of the Art and Prospects in Metal-
Organic Framework (MOF)-Based and MOF-Derived Nanocatalysis.
Chem. Rev. 2020, 120, 1438−1511.
(6) (a) Chun, J.; Lee, H. S.; Jung, I. G.; Lee, S. W.; Kim, H. J.; Son, S.
U. Cu2O: A Versatile Reagent for Base-Free Direct Synthesis of NHC-
Copper Complexes and Decoration of 3D-MOF with Coordinatively
Unsaturated NHC-Copper Species. Organometallics 2010, 29, 1518−
1521. (b) Chun, J.; Jung, I. G.; Kim, H. J.; Park, M.; Lah, M. S.; Son, S.
U. Concomitant Formation of N-Heterocyclic Carbene−Copper
Complexes within a Supramolecular Network in the Self-Assembly of
Imidazolium Dicarboxylate with Metal Ions. Inorg. Chem. 2009, 48,
6353−6355. (c) Dong, Y.; Li, Y.; Wei, Y.-L.; Wang, J.-C.; Ma, J.-P.; Ji, J.;
Yao, B.-J.; Dong, Y.-B. A N-heterocyclic tetracarbene Pd(ii) moiety
containing a Pd(ii)-Pb(ii) bimetallic MOF for three-component
cyclotrimerization via benzyne. Chem. Commun. 2016, 52, 10505−
10508. (d) Wei, Y.-L.; Li, Y.; Chen, Y.-Q.; Dong, Y.; Yao, J.-J.; Han, X.-
Y.; Dong, Y.-B. Pd(II)-NHDC-Functionalized UiO-67 Type MOF for
Catalyzing Heck Cross-Coupling and Intermolecular Benzyne-
Benzyne-Alkene Insertion Reactions. Inorg. Chem. 2018, 57, 4379−
4386. (e) Jeoung, S.; Kim, S.; Kim, M.; Moon, H. R. Pore Engineering
of Metal-organic Frameworks with Coordinating Functionalities.
Coord. Chem. Rev. 2020, 420, 213377.
(7) Arduengo, A. J., III; Harlow, R. L.; Kline, M. A stable crystalline
carbene. J. Am. Chem. Soc. 1991, 113, 361.
(8) (a) Hopkinson, M. N.; Richter, C.; Schedler, M.; Glorius, F. An
Overview of N-heterocyclic Carbenes. Nature 2014, 510, 485−496.
(b) Peris, E. Smart N-Heterocyclic Carbene Ligands in Catalysis. Chem.
́
Rev. 2018, 118, 9988−10031. (c) de Fremont, P.; Marion, N.; Nolan, S.
P. Carbenes: Synthesis, Properties, and Organometallic Chemistry.
Coord. Chem. Rev. 2009, 253, 862−892. (d) Ranganath, K. V. S.;
Onitsuka, S.; Kumar, A. K.; Inanaga, J. Recent Progress of N-
heterocyclic Carbenes in Heterogeneous Catalysis. Catal. Sci. Technol.
2013, 3, 2161−2181.
(9) Smith, C. A.; Narouz, M. R.; Lummis, P. A.; Singh, I.; Nazemi, A.;
Li, C.-H.; Crudden, C. M. N-Heterocyclic Carbenes in Materials
Chemistry. Chem. Rev. 2019, 119, 4986−5056.
(10) (a) Øien-Ødegaard, S.; Bouchevreau, B.; Hylland, K.; Wu, L.;
Blom, R.; Grande, C.; Olsbye, U.; Tilset, M.; Lillerud, K. P. UiO-67-
type Metal-Organic Frameworks with Enhanced Water Stability and
Methane Adsorption Capacity. Inorg. Chem. 2016, 55, 1986−1991.
(b) Ding, L.-G.; Yao, B.-J.; Jiang, W.-L.; Li, J.-T.; Fu, Q.-J.; Li, Y.-A.; Liu,
Z.-H.; Ma, J.-P.; Dong, Y.-B. Bifunctional Imidazolium-Based Ionic
Liquid Decorated UiO-67 Type MOF for Selective CO2 Adsorption
and Catalytic Property for CO2 Cycloaddition with Epoxides. Inorg.
Chem. 2017, 56, 2337−2344.
(11) (a) Shimazaki, Y.; Yajima, T.; Tani, F.; Karasawa, S.; Fukui, K.;
Naruta, Y.; Yamauchi, O. Syntheses and Electronic Structures of One-
Electron-Oxidized Group 10 Metal(II)−(Disalicylidene)diamine
Complexes (Metal = Ni, Pd, Pt). J. Am. Chem. Soc. 2007, 129, 2559−
2568. (b) Mukhopadhyay, K.; Sarkar, B. R.; Chaudhari, R. V. Anchored
Pd Complex in MCM-41 and MCM-48: Novel Heterogeneous
1826
https://dx.doi.org/10.1021/acs.joc.0c02641
J. Org. Chem. 2021, 86, 1818−1826