Bifunctional N-Doped Co@C Catalysts for Base-Free Transfer Hydrogenations of Nitriles: Controllable Selectivity to Primary Amines vs Imines

Article abstract of DOI:10.1021/acscatal.6b02327

The transfer hydrogenation of nitriles is an important and alternative strategy to produce primary amines or imines, both of which play a crucial role in the synthesis of fine chemicals and pharmaceuticals. Nevertheless, developing highly active bifunctional catalyst system with controllable selectivity for these reactions still remains a huge challenge. In this study, we presented a bifunctional N-doped Co@C catalyst system (Co@NC) for the selective transfer hydrogenation of nitriles into either primary amines or imines. The Co@NC was prepared by the direct pyrolysis of an N-containing Co-MOF under an inert atmosphere, where the N-containing ligands could be transformed into highly graphitic N-doped carbon, endowing the catalysts with high-density special basic sites, while the Co²⁺ ions were reduced to uniform Co nanoparticles which were dispersed on or embedded in N-doped graphitic structures. Under base-free conditions with isopropyl alcohol as both proton donor and solvent, the optimized Co@NC-900 (obtained at 900 °C) catalyst could convert nitriles into primary amines or imines at will with surprising selectivities (mostly higher than 90%), depending on the solvent volume added to the reaction systems. Furthermore, a possible reaction mechanism was proposed. The N-derived basic sites on Co@NC could play a role similar to that of the base additives, which not only inhibit the formation of polyamine or prevent the products stacked on the surface of catalysts but also effectively promote the transfer hydrogenation of nitriles. The generated corresponding primary imines could controllably attack the primary imine intermediates to form imines by adjusting the concentration of Co@NC. It is clear that this strategy offers a high-performance catalyst system for base-free transfer hydrogenations of nitriles to selectively produce primary amines vs imines.

Full text of DOI:10.1021/acscatal.6b02327

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Article
Bi-Functional N-Doped Co@C Catalysts for
Base-Free Transfer Hydrogenations of Nitriles:
Controllable Selectivity to Primary Amines vs Imines
Jilan Long, Kui Shen, and Yingwei Li
ACS Catal., Just Accepted Manuscript • DOI: 10.1021/acscatal.6b02327 • Publication Date (Web): 27 Nov 2016
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ACS Catalysis
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Bi-Functional N-Doped Co@C Catalysts for Base-Free Trans-
fer Hydrogenations of Nitriles: Controllable Selectivity to Pri-
mary Amines vs Imines
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Jilan Long,†‡ Kui Shen,†* and Yingwei Li,†*
†Key Laboratory of Fuel Cell Technology of Guangdong Province, School of Chemistry and Chemical Engineering, South
China University of Technology, Guangzhou 510640, People’s Republic of China
‡Chemical Synthesis and Pollution Control Key Laboratory of Sichuan Province, College of Chemistry and Chemical Engiꢀ
neering, China West Normal University, Nanchong 637000, People’s Republic of China
ABSTRACT: The transfer hydrogenation of nitriles is an important and alternative strategy to produce primary amines or imines,
both of which play a crucial role in the synthesis of fine chemicals and pharmaceuticals. Nevertheless, developing highly active biꢀ
functional catalyst system with controllable selectivity for these reactions still remains a huge challenge. In this study, we presented
a biꢀfunctional Nꢀdoped Co@C catalyst system (Co@NC) for the selective transfer hydrogenation of nitriles into either primary
amines or imines. The Co@NC was prepared by the direct pyrolysis of an Nꢀcontaining CoꢀMOF in inert atmosphere, where the Nꢀ
containing ligands could be transformed into highly graphitic Nꢀdoped carbon, endowing the catalysts with highꢀdensity special
basic sites, while the Co2+ ions were reduced to uniform Co nanoparticles which were dispersed on or embedded in Nꢀdoped graꢀ
phitic structures. Under baseꢀfree conditions with isopropanol as both protonꢀdonor and solvent, the optimized Co@NCꢀ900 (obꢀ
o
tained at 900 C) catalyst could convert nitriles into primary amines or imines at will with surprising selectivities (mostly higher
than 90%), depending on the solvent volume added to the reaction systems. Furthermore, a possible reaction mechanism was proꢀ
posed. The Nꢀderived basic sites on Co@NC could play a similar role as the base additives which not only inhibit the formation of
polyamine or prevent the products stacked on the surface of catalysts, but also effectively promote the transfer hydrogenation of
nitriles. The generated corresponding primary imines could controllably attack the primary imine intermediates to form imines by
adjusting the concentration of Co@NC. It is clear that this strategy offers a highꢀperformance catalyst system for baseꢀfree transfer
hydrogenations of nitriles to selectively produce primary amines vs imines.
KEYWORDS: cobalt-based catalysts, selective transfer hydrogenations, nitriles, primary amines, imines
INTRODUCTION
As compared to the traditional hydrogenation process, transꢀ
fer hydrogenation has been proposed recently as an alternative
strategy, which utilizes various alternatives including phosꢀ
phinicacid salts,9 aliphatic alcohols,10 hydrazines,11 formic acid
salts,12 and inorganic hydride,13 as protonꢀdonors to replace
molecule hydrogen used in the traditional protocol. Among
these donors, alcohols (especially isopropanol) were highly
promising agents owing to the characters of nonꢀpoisonous
and mild reaction conditions.14 Transfer hydrogenation of niꢀ
triles by using isopropanol as protonꢀdonor can avoid the hanꢀ
dling of autoclaves and hydrogen, and thus would represent a
green, safe, and economic protocol.15
Amines and imines, as significant intermediates, play reꢀ
markable roles in the synthesis of a vast number of pharmaꢀ
ceuticals and agrochemicals, and thus have attracted extensive
interests from both academic and industrial researchers to exꢀ
plore more efficient strategies to establish carbon–nitrogen
bonds.1 Among the various routes, heterogeneous catalytic
methods have provided numerous efficient and environmentꢀ
benign strategies towards the synthesis of amines and imines,
representing a crucial technology especially for reducing enviꢀ
ronmental hazards and decreasing energy consumption as well
as achieving high atom efficiency.2 To date, numerous heterꢀ
ogeneous catalytic systems have been developed. For instance,
both amines and imines could be synthesized by hydrogenaꢀ
tion of nitriles over a variety of heterogeneous catalysts based
on noble metals, such as Pd,3 Ru,4 Rh,5 and Ir.6 In this regard,
hydrogenation of nitriles established a convenient and valuaꢀ
ble process for the preparation of both amines and imines.2
However, traditional hydrogenation of nitriles with molecular
hydrogen as reductant was always characterized by an enviꢀ
ronmentallyꢀunfriendly and harsh synthetic process, such as
the use of basic additives7 and high H2 pressures, as well as
noble metal catalysts, which greatly limited their industrial
applications.8
Nevertheless, in order to achieve high yields, most of the
transfer hydrogenation of nitriles have been conducted in the
presence of basic additives over nobleꢀmetal catalysts (such as
Ru10a,16 or Pd17a) and some soluble nonꢀprecious metalꢀbased
catalysts (such as Fe17b, Ni 17c, Table S1). Furthermore, to our
knowledge, the preparation of primary amines and imines
from hydrogenation of nitriles should be carried out in sepaꢀ
rate catalytic systems. So far, there is still no report on the use
of a versatile catalytic system that is able to selectively proꢀ
duce both primary amines and imines with an excellent switch
in selectivity just by adjusting the reaction conditions. The
development of highly active nonꢀnoble catalysts for the transꢀ
fer hydrogenation of nitriles with controllable selectivity to
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primary amines vs imines under baseꢀfree condition is highly scope (TEM, JEOL, JEMꢀ2010HR) with energyꢀdispersive Xꢀ
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desirable, but remains a significant challenge.
ray spectroscopy (EDS) analysis. Xꢀray Photoelectron Specꢀ
troscopy (XPS) measurement was performed on a Kratos Axis
Ultra DLD system with a base pressure of 10−9 Torr. The basic
property was determined by CO2ꢀTPD measured on a Miꢀ
cromeritics AutoChem II 2920 instrument equipped with a
highly sensitive linear thermal conductivity detector (TCD),
which was connected to a mass spectrometer (VARIAN). Typꢀ
ically, 70 mg of activated sample was pretreated under a flow
of Helium (50 mL minꢀ1) at 700 °C for 1 h. Then the sample
was cooled to 100 °C under a flow of Helium. After adsorpꢀ
tion of CO2, the sample was purged in Helium atmosphere at
100 °C. The TPD data were collected from 100 °C to 700 °C
at a heating rate of 20 °C minꢀ1 in a flow of Helium.
In this contribution, we report highly efficient biꢀfunctional
Nꢀdoped Co@C catalyst system (Co@NC) for the transfer
hydrogenation of nitriles under baseꢀfree conditions with isoꢀ
propanol as protonꢀdonor to realize the controllable and selecꢀ
tive synthesis of imines or amines. The Co@NC were preꢀ
pared by the direct pyrolysis of an Nꢀcontaining cobaltꢀbased
MOF ([Co(1,4ꢀbdc)(ted)0.5]·2DMF·0.2H2O) in inert atmosꢀ
phere. In the pyrolysis process, the Co ions of CoꢀMOF could
be transformed into highly dispersed Co NPs which were emꢀ
bedded in ligandꢀderived Nꢀdoped graphitic carbon matrix.
The N sites derived from the triethylenediamine moiety in
MOF could be reserved partly after pyrolysis, which potentialꢀ
ly endowed the catalysts with abundant Lewis basic sites. Theꢀ
se basic sites could facilitate the proton transfer and deliver the
free proton to the activated nitrile molecules to produce primaꢀ
ry imines, which could further attack the primary imine interꢀ
mediates to form imines under low concentration of basic sites,
giving a perfect switch between primary amines vs imines just
by adjusting the dosage of solvent.
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Catalytic reactions. The transfer hydrogenation of nitriles
was carried out in a 25 mL Schlenk tube (the largeꢀscale synꢀ
thesis (5 mmol reactant) was carried out in a 100 mL Schlenk
tube). The Schlenk tube was degassed and purged several
times with pure N2 to remove the air after the addition of niꢀ
trile, isopropanol and catalyst. Then the Schlenk tube was
transferred into an oil bath that was preheated to 80 °C. After
reaction, the mixtures were identified by GC–MS, and the
conversion of nitrile and the products yields were determined
by gas chromatography (GC) with nitrobenzene as an internal
standard.
EXPERIMENTAL SECTION
Chemicals. All chemicals were purchased from commercial
sources and used without further treatments. All solvents were
analytical grade and distilled prior to use.
The recyclability of the Co@NCꢀ900 was further investiꢀ
gated under the above reaction conditions (0.5 mmol of 2ꢀ
methylbenzonitrile, 10 mol% of catalysts, 1 mL of isopropanol,
48 h, 80 oC). The detailed procedures were shown in Figure S1.
Typically, the mixture containing Co@NCꢀ900 was transꢀ
formed into a clean tube after reaction. Then the reaction tube
was washed by isopropanol with ultrasonic treatment for sevꢀ
eral times until the reaction tube were clean. Then the
Co@NCꢀ900 was easily separated from the reaction solution
by placing a magnet close to the tube due to its good magnetic
property (Figure S1). After removing the solution, the
Co@NCꢀ900 was washed with isopropanol for several times
and then dried at 100 °C in an oven. In order to reduce the loss,
the Co@NCꢀ900 should be removed from the tube after drying
completely. Subsequently, the Co@NCꢀ900 was reduced by
H2 flow at 400 °C for 2 h, and then reused as the catalyst in the
next run.
Synthesis of CoꢀMOF ([Co(1,4ꢀbdc)(ted)0.5]·2DMF·0.2
H2O). Typically, a mixture of Co(NO)3·6H2O (0.9 mmol), 1,4ꢀ
benzenedicarboxylic acid (H2BDC, 0.9 mmol), triethylenediꢀ
amine (TED, 0.5 mmol), and 15 ml DMF were added to a
Teflonꢀlined autoclave and heated statically at 120 °C in an
oven for 2 days (Scheme 1). The purple products were washed
with DMF and methanol, and then dried under vacuum at
150 °C for 12 h.
Synthesis of Co@NC catalysts. The pyrolysis of CoꢀMOF
was carried out in a tubular furnace under argon atmosphere
with a flow rate of 20 mL/min. The samples were heated at a
heating rate of 2 °C/min from room temperature to 200 °C and
kept at this temperature for 2 h. Then the temperature was
increased to five different target temperatures (i.e. 500 °C,
600 °C, 700 °C, 800 °C, and 900 °C) with a heating rate of
2 °C/min and kept for 8 h, followed by cooling down to ambiꢀ
ent temperature. The obtained black powders were denoted as
Co@NCꢀ500, Co@NCꢀ600, Co@NCꢀ700, Co@NCꢀ800, and
Co@NCꢀ900, respectively. Owing to the easy oxidation charꢀ
acter of metallic cobalt, the samples were preserved in pure N2
before being used as catalysts.
RESULTS AND DISCUSSION
The powder XRD patterns of the CoꢀMOF (Figure S2)
matched well with the published XRD patterns in literatures,18
confirming the asꢀsynthesized MOF structure in this work.
The XRD patterns of the Co@NC nanocatalysts (Figure 1)
exhibited four diffraction peaks at around 44.3°, 51.6°, 76.1°,
and 92.3°, respectively, which corresponded to the characterisꢀ
tic diffractions of (1 1 0), (2 0 0), (2 2 0) and (3 1 1) lattice
planes of metallic Co (JCPDS No. 15ꢀ0806).19 This indicated
Characterization. Powder Xꢀray diffraction patterns of the
CoꢀMOF and Co@NC were recorded on a Rigaku diffractomꢀ
eter (D/MAXꢀIIIA, 3 kW) by Cu Kα radiation (40 kV, 30 mA,
0.1543 nm). BET surface areas and pore sizes were obtained
from N2 adsorption/desorption isotherms at 77 K with a Miꢀ
cromeritics ASAP 2020M instrument. Before measurements,
the samples were degassed at 150 °C for 12 h. The Co content
of the Co@NC samples was measured quantitatively by atomꢀ
ic absorption spectroscopy (AAS) on a Hitachi Zꢀ2300 instruꢀ
ment. The surface topography of CoꢀMOF and catalysts, as
well as the element distribution of Co@NC were investigated
by a Scanning Electron Microscope (SEM, MERLIN of
ZEISS), the size and morphology of the Co@NC samples
were determined by using a Transmission Electron Microꢀ
Ⅱ
the Co in CoꢀMOF have been successfully reduced to Coo by
ligandꢀderived carbon under high temperature. The mean size
of Co NPs in Co@NCꢀ500, Co@NCꢀ600, Co@NCꢀ700,
Co@NCꢀ800 and Co@NCꢀ900 was 2.15 nm, 3.83 nm, 4.79
nm, 7.19 nm and 8.63 nm respectively according to the Scherꢀ
rer analysis based on the XRD results, indicating the mean
size of nanoparticles increased with an increase in the calcinaꢀ
tion temperature. In addition, the Co diffraction peaks of the
catalysts prepared at higher pyrolysis temperatures exhibited
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formation of large nanoparticiles after pyrolysis. It was also
improved intensities owing to the higher crystallization degree
and larger Co particles.20
worth to note that the pyrolysis temperature had little impact
on the structural properties of the asꢀobtained Co@NC samꢀ
ples, since the BET surface areas of the samples had changed
little when the pyrolysis temperatures increased.
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The contents of Co in the catalysts were measured by AAS,
and the proportion of other elements was analyzed by element
analysis. The results in Table S3 indicated that the total metal
contents of CoꢀMOF and its derived nanocatalysts were
around 20 wt% and 35ꢀ40 wt%, and the N contents were
around 9 wt% and 1 wt%, respectively.
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The surface morphology of CoꢀMOF and Co@NC materials
were investigated by SEM. As shown in Figure 3, all the
Co@NC samples kept the similar shapes to their parent Coꢀ
MOF except a more rough and porous surface. It was also
worth to note that the surface of the catalysts became rougher
with an increase in the pyrolysis temperature. In addition, elꢀ
emental mapping pointed out that C, N, and Co were evenly
distributed in the Co@NC catalysts after pyrolysis (Figure 4).
Scheme 1. Schematic illustration of the process used for the synꢀ
thesis of Co@NC.
Figure 1. Powder XRD patterns of the Co@NC samples: (a)
Co@NCꢀ500, (b) Co@NCꢀ600, (c) Co@NCꢀ700, (d) Co@NCꢀ
800, and Co@NCꢀ900 before (e) and after catalytic reaction (f).
The carbonization of CoꢀMOF generated plentiful mesopoꢀ
rosity, leading to different pore structures between MOF and
its derived Co@NC nanocatalysts. As shown in Figure S3, the
N2 adsorption/desorption isotherms of CoꢀMOF exhibited a
typical typeꢀI adsorption curve, corresponding to the solely
microporous structure. However, the N2 adsorption/desorption
isotherms of all the Co@NC samples exhibited a typeꢀIV adꢀ
sorption with an apparent hysteresis loop in the P/P0 range of
0.5−1.0 (Figure 2a). These results indicated the presence of a
large amount of mesopores in the Co@NC materials, which
was confirmed by their corresponding pore distribution curves
(Figure 2b). In addition, as shown in Table S2, a huge drop in
BET surface area was observed after carbonization (around
100−200 m2 gꢀ1 for the Co@NC materials prepared at different
temperatures), which might be due to the collapse of main
frameworks and the decrease in microporosity, as well as the
Figure 2. (a) Nitrogen adsorption/desorption isotherms of various
Co@NC prepared at different temperatures and (b) the correꢀ
sponding BJH poreꢀsize distribution curves.
More structural information was further revealed by TEM
characterization. The TEM images of Co@NC prepared at
different pyrolysis temperatures were displayed in Figure 5. It
was quite clear that higher pyrolysis temperatures could lead
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to the formation of larger Co NPs, as confirmed by their correꢀ
6b).25 However, owing to the influence of magnetic metal ions
(Co2+), this bonding energy was slightly higher than that of
amino nitrogen (399.6 eV).26 After pyrolysis, the N 1s spectra
of Co@NCꢀ900 appeared two new peaks at 398.88 eV and
401.28 eV, which could be assigned to the pyridinic N and
graphitic N, respectively, indicating that the N atoms were
doped successfully into the Co/NC materials,27 which was also
in accordance with the SEMꢀEDS results (Figure 4d, 5f). Note
that these N sites might endow the catalysts with plentiful
Lewis basic sites, which are believed to be able to facilitate the
transfer hydrogenation reactions.28 The Co 2p and N 1s XPS
spectra of the samples synthesized at other pyrolysis temperaꢀ
tures were also shown in Figure S4. Obviously, the intensities
of graphitic N 1s peaks increased with the increase of pyrolyꢀ
sis temperatures, indicating that high temperature was benefiꢀ
cial to the graphitization of carbon. In addition, the intensities
of Co 2p XPS peaks also enhanced with the increase of pyrolꢀ
ysis temperatures, demonstrating the crystallinity of Co nanoꢀ
particles was improved and more Co nanoparticles were exꢀ
posed on the surface of catalysts. These results were also in
accordance with the XRD results that more peaks correspondꢀ
ing to different lattice plane were appeared in the XRD patꢀ
terns and the intensities of these peaks also increased at high
temperatures.
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sponding size distribution (Figure 5aꢀ5e). In addition, the Co
nanoparticles were uniformly dispersed in Co@NCꢀ900 with
an average particle size of 15.44 ± 0.56 nm (Figure 5e), and no
significant aggregates were observed. Figure 5f highlighted a
typical metallic Co nanoparticle with crystal lattices of 0.205
nm, which were assigned to the (1,1,1) interplanar spacing of
metallic Co.21 The inserted EDS image further confirmed the
coexistence of C, N and Co element in an individual particle
(Inset of Figure 5f). Figure 5g and 5h clearly pointed out that
the Co NPs were encapsulated by wellꢀordered graphitic layers
with a typical distance value of graphite (0.34 nm).22 The forꢀ
mation of graphitic structure could efficiently prevent the agꢀ
gregation of nanoparticles and facilitate the electron transferꢀ
ring, and thereby improved the catalytic activity.
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Figure 3. SEM images of (a)CoꢀMOF, (b) Co@NCꢀ500, (c)
Co@NCꢀ600, (d) Co@NCꢀ700, (e) Co@NCꢀ800, (f) Co@NCꢀ
900.
Figure 4. SEM image (a) and the elemental mapping of Co@NCꢀ
900: (b) C, (c) Co, (d) N.
Then we further performed CO2ꢀTPD to analyze the basic
property of the CoꢀMOF and Co@NC. The CO2 desorption
The XPS spectra of Co@NCꢀ900 and CoꢀMOF were shown
in Figure 6. The Co 2p peaks of CoꢀMOF at around 781.25 eV
and 796.75 eV could be assigned to the characteristic peaks of
highꢀspinning Co2+.23 After pyrolysis, the Co 2p spectra of
Co@NCꢀ900 showed two distinct peaks at 778.96 eV (FWHM
of 1.74 eV) and 793.54 eV (FWHM of 1.8 eV) with two obviꢀ
ous 2p satellite peaks (the FWHMs were 6.71 eV and 4.86 eV,
respectively), which were lower than that of the CoꢀMOF by
~2.29 eV and ~3.21 eV, respectively, indicating that the Co(II)
ions in CoꢀMOF were in-situ reduced to metallic Co during
thermal decomposition (Figure 6a). This result was also conꢀ
sistent with the reported experimental regularity that if the
reduction potential of centre ions of MOFs was ꢀ0.27 volts or
higher (such as Co2+, Ni2+, Cu2+), the central metal ions would
be reduced to metal nanoparticles by the direct pyrolysis in
inert atmosphere.24 In addition, an obvious peak of CoꢀMOF
appearing at 399.83 eV could be assigned to the N 1s of triꢀ
ethylenediamine coordinated with a Co mental ion (Figure
o
temperature of CoꢀMOF was at around 275 C (Figure S5),
indicating a part of N atoms exposed on the surface of this
MOF. As shown in Figure 7, three obvious peaks appeared at
o
o
o
around 150 C, 220 C and 450 C in the CO2ꢀTPD curves.
The total peak areas ratios of Co@NCꢀ500, Co@NCꢀ600,
Co@NCꢀ700, Co@NCꢀ800, Co@NCꢀ900 were about 1.03: 1:
1.29: 1.29: 1.18. Generally, the CO2ꢀTPD curve can reveal
efficiently the strength and the density of the basic site in the
catalysts on the basis of the position and peak area of CO2ꢀ
desorption peaks. Therefore, it was obviously that as the pyꢀ
rolysis temperature increased, the density and the strength of
the basic sites in the Co@NC just changed slightly. It was
worth to note that these basic sites were derived from the triꢀ
ethylenediamine groups in the CoꢀMOF.
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Figure 5. TEM images of Co@NC. (a) Co@NCꢀ500, (b) Co@NCꢀ600, (c) Co@NCꢀ700, (d) Co@NCꢀ800, (eꢀh) Co@NCꢀ900. The insets
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in (aꢀe) are their corresponding size distribution of Co nanoparticles. The inset in (f) is its corresponding EDS spectrum.
Subsequently, the transfer hydrogenation of nitriles was
chosen as a model reaction to investigate the activity of variꢀ
ous Co@NC catalysts. The catalytic reaction was carried out
Nevertheless, there was no additional basic additive in the
present system. Thus the formation of primary amine should
be attributed to the special basic sites (N sites), which were
derived from the partial preservation of the triethylenediamine
moiety in CoꢀMOF during pyrolysis (Figure 7).
o
in N2 atmosphere at 80 C by using isopropanol as both proꢀ
tonꢀdonor and solvent under baseꢀfree conditions. The converꢀ
sion of 2ꢀmethylbenzonitrile and the selectivity of products
over various catalysts are shown in Table 1. The blank run
(without any catalysts) gave essentially no activity in this sysꢀ
tem (even using C as catalyst) after 48 h of reaction
Figure 6. XPS spectra of Co@NCꢀ900 and asꢀprepared CoꢀMOF,
(a) Co 2p and (b) N 1s.
Figure 7. CO2ꢀTPD profiles for Co@NCꢀ500, Co@NCꢀ600,
Co@NCꢀ700, Co@NCꢀ800, and Co@NCꢀ900.
(Table 1, entries 1ꢀ2). This result indicated the Co NPs in
Co@NC were the active sites for the transfer hydrogenations
of nitriles. To our delight, all the asꢀsynthesized Co@NC cataꢀ
lysts were highly active for this transformation. It was quite
clear that the catalysts prepared at higher pyrolysis temperaꢀ
tures exhibited higher catalytic activity (Table 1, entries 3ꢀ7).
It can be seen that the Co@NCꢀ500 catalyst only gave 63%
conversion of 2ꢀmethylbenzonitrile with 73.7% selectivity to
2ꢀmethylbenzylamine (Table 1, entry 3). With the increase of
pyrolysis temperatures, the conversion and selectivity inꢀ
creased dramatically. The Co@NCꢀ900 was found to be the
highest active catalyst among these catalysts investigated in
this system, which could almost completely catalyse the transꢀ
fer hydrogenation of 2ꢀmethylbenzonitrile, providing around
80% of selectivity to 2ꢀmethylbenzylamine (Table 1, entry 7).
It was worth to note that the hydrogenation of nitriles to genꢀ
erate amines always proceed under alkalinity conditions, beꢀ
cause base additives can facilitate the transfer of electrons.28
Interestingly, the selectivities of products in our system
could be efficiently controlled by simply regulating the volꢀ
ume of solvent (Table 1, entries 7ꢀ10). The selectivities of the
corresponding primary amines was remarkably enhanced by
decreasing the volume of isopropanol to 1 mL, furnishing a
quantitative yield of 2ꢀmethylbenzylamine (Table 1, entry 9).
Whereas increasing the volume of isopropanol to 4 mL resultꢀ
ed in
a
great decrease in the selectivity of 2ꢀ
methylbenzylamine, while the selectivity of Nꢀ(2ꢀ
methylbenzylidene)ꢀ1ꢀ(oꢀtolyl) soared to 95.5% (Table 1, enꢀ
try 10). In addition, the functional curves with respect to the
volume of isopropanol and the distribution of products were
shown in Figure S6. Obviously, this highꢀperformance catalyst
system provided a perfect switch between primary amines and
imines. In fact, the Co@NCꢀ900, to the best of our knowledge,
was the first example to be able to selectively produce both
primary amines and imines from nitriles with an excellent
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Page 6 of 11
with all of the conversions of 2ꢀmethylbenzonitrile less than
5% (Table 2, entries 1ꢀ4), due to the absent of Nꢀderived basic
sites over Co@Cꢀ900 or basic additive.28 Furthermore, the 2ꢀ
methylbenzylamine could be hardly detected in these systems,
which was attributed to the lack of basic sites to control the
selectivity (Table 2, entries 1ꢀ4).
switch in selectivity just by controlling the solvent volume
1
2
3
4
5
6
7
8
(Table S1).Considering the similar reaction conditions of variꢀ
ous parallel catalytic tests in terms of catalyst addition, subꢀ
strate dosage, reaction temperature and time, we concluded
that the concentration of the Nꢀderived basic sites played the
key role in controlling the product selectivities. Furthermore,
the reaction also proceeded smoothly when the amount of
reactant was increased to 5 mmol, affording more than 90%
conversions after prolonging the reaction time to 55 h.
Table 2. Transfer hydrogenation of 2ꢀmethylbenzonitrilea
9
Table 1. Transfer hydrogenation of 2ꢀmethylbenzonitrile over
different catalystsa
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
Sel. (%)
Ent
ry
Sol.
Con.
(%)
Catalyst
(mL)
I
II
III
1b
2b
Co@C-900
Co@C-900
1
2
<5
<5
-
52.7
47.3
Sel. (%)
II
Sol.
(mL)
2
En-
try
Con.
(%)
Catalyst
-
-
-
48.9
53.4
29.1
51.1
46.6
70.9
10.3
16.4
32.2
21.1
I
III
-
3b
4b
5c
6c
7c
8c
Co@C-900
3
4
1
2
3
4
<5
<5
1
2b
3
-
Trace
<3
-
-
Co@C-900
C
2
0
25.6
26.3
21.7
20.8
15.4
20.0
0
74.4
0
Co@NC-900(67)
Co@NC-900(67)
Co@NC-900(67)
Co@NC-900(67)
45.5 70.5 19.2
41.5 53.8 29.8
17.9 40.3 27.5
11.9 56.5 22.4
Co@NC-500
Co@NC-600
Co@NC-700
Co@NC-800
Co@NC-900
Co@NC-900
Co@NC-900
Co@NC-900
Co@NC-900
Co@NC-900
2
63.0
73.4
80.6
89.8
>99
73.7
78.3
79.2
84.6
80.0
>99
47.2
4.5
>99
3.7
4
2
0
5
2
0
aReaction condition: 2ꢀmethylbenzonitrile (0.5 mmol), catalyst
(Co 10 mol%), 80 C, 48 h. CoꢀMOFꢀ71 as sacrificial temꢀ
plate, catalyst (Co 10 mol%). cZIFꢀ67 as sacrificial template,
catalyst (Co 10 mol%).
6
2
0
o
b
7
2
0
8
1
>99
0
Subsequently, another Nꢀcontaining ZIFꢀ6730 (Co(mim)2,
mim = 2ꢀmethylimidazole) was also employed as sacrificial
template to prepare another Coꢀbased catalyst (denoted as
Co@NCꢀ900(67)). ZIFꢀ67 employed a fully saturated coordiꢀ
nation model for both Co and N sites in structure, which was
greatly different from the CoꢀMOF structure (unsaturated coꢀ
ordination for both Co and N sites). As a result, the strength of
basic sites of Co@NCꢀ900(67) was much lower than that of
Co@NCꢀ900, as was confirmed by its low desorption temꢀ
9
3
>99
52.8
95.5
0
0
10
11c
12c
4
>99
0
10
40
93.0
91.3
0
96.3
0
o
aReaction condition: 2ꢀmethylbenzonitrile (0.5 mmol), catalyst
(Co 10 mol%), 80 C, 48 h. The C was obtained by using
aqua regia to remove the Co from the Co@NCꢀ900. 2ꢀ
methylbenzonitrile (5 mmol), catalyst (Co 10 mol%), 80 C,
perature in CO2ꢀTPD profile (lower than 450 C, Figure S7),
o
b
although the Nꢀcontent of both catalysts was almost the same.
As shown in Table 2, Co@NCꢀ900(67) only possessed a modꢀ
erate reaction activity and low selectivity for this reaction,
probably due to the lack of strong basic sites. These results
indicated that the conversion of 2ꢀmethylbenzonitrile and the
c
o
55 h.
To elucidate the significance of basic sites, two different
MOFs were also applied as sacrificial templates to prepare
other two Coꢀbased catalysts for this reaction. MOFꢀ7129
(Co(1,4ꢀbdc)(DMF), 1,4ꢀbdc=1,4ꢀbenzenedicarboxylic acid,
DMF = N,N'ꢀdimethyl formamide ) was firstly employed as
sacrificial template to prepare the catalyst (denoted as Co@Cꢀ
900) by using the same pyrolysis conditions. It was worth to
point out that there were no basic sites detected in Co@Cꢀ900
due to the Nꢀfree feature of the parental MOFꢀ71 (DMF moleꢀ
cules have been removed before pyrolysis). As expected,
Co@Cꢀ900 exhibited poor catalytic activities for this reaction
selectivity
of
2ꢀmethylbenzonitrile
and
Nꢀ(2ꢀ
methylbenzylidene)ꢀ1ꢀ(oꢀtolyl) were greatly influenced by the
concentration and strength of basic sites, as well as the strucꢀ
ture of catalysts.
It was of importance to certify that the heterogeneous cataꢀ
lyst was stable enough and could be reused. Firstly, the chemiꢀ
cal state of Co nanoparticles after reaction was confirmed by
XPS spectrum (Figure S8). The bonding energy of 778.5 eV
and 793.4 eV could be assigned to the character of Co (0),
while the bonding energy of 781.0 eV and 796.5 eV matched
well with the character of Co (II). This indicated that
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Table 3. Transfer hydrogenation various nitriles to primary aminesa
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
1 mL iꢀPrOH
4 mL iꢀPrOH
Enꢀ
try
Substrate
t (h)
48
Con.
(%)
Sel. (%)
t (h)
Con. (%)
>99
Sel. (%)
1
2
>99
48
45
95.5
95.0
>99
50
>99
>99
>99
>99
3
46
40
48
48
48
46
>99
>99
>99
>99
>99
>99
40
50
60
60
60
72
>99
>99
>99
>99
>99
>99
98.0
>99
97.5
>99
98.1
4
>99
5b
6b
7b
8b
97.0
96.0
95.0
>99
91.0
9b
55
>99
72
>99
>99
85.9
80.5
10b
11c
24
48
>99
>99
90.0
24
72
>99
>99
91.0
90.0
a Reaction condition: nitirles 0.5 mmol, Co@NCꢀ900 catalyst (Co 10 mol%), iꢀPrOH solvent; b100 oC; c120 oC.
the CoII and Co0 coꢀexisted in the used catalysts. Therefore,
the catalysts should be reduced at H2 flow for 2 h at 400 C
investigated, affording the corresponding benzylamines in
quantitative yields in 1 mL isopropanol (Table 3, entries 1ꢀ4),
while providing the corresponding imine products with more
than 95% selectivities in 4 mL isopropanol (Table 3, entries 1ꢀ
4). Likewise, the electronꢀwithdrawing substrates, including 4ꢀ
o
before reuses. Subsequently, we investigated the recyclability
of the Co@NCꢀ900 catalyst under the conditions of 80 oC and
1 mL isopropanol. Results were exhibited in Figure S9, where
no apparent loss in conversion and selectivity was observed
even up to four runs, indicating its excellent recyclability.
Further investigation of the general applicability of this system
was performed under the optimum reaction conditions.
bromobenzonitrile,
4ꢀchlorobenzonitrile
and
4ꢀ
fluorobenzonitrile, should carry out the transfer hydrogenation
at a higher temperature, giving the desired benzylamine prodꢀ
ucts with more than 95% selectivities (Table 3, entries 5ꢀ7), or
generating the corresponding imines with more than 97% seꢀ
lectivities (Table 3, entries 5ꢀ7), respectively. Furthermore, it
is necessary to point out that the transfer hydrogenation of
aliphatic nitriles is always a big challenge, because the transfer
hydrogenation of the C≡N group in aliphatic nitriles could
easily result in the formation of the corresponded methyl
group.31 However, in the present system, aliphatic nitriles such
As expected, the Co@NCꢀ900 could catalyse smoothly the
transfer hydrogenations of a broad scope of nitriles to selecꢀ
tively produce their corresponding primary amines or imines
with a perfect switch only by adjusting the volume of solvent
(Table 3). Specifically, the electronꢀdonating group substrates,
such as 2ꢀmethylbenzonitrile, 3ꢀmethylbenzonitrile, 4ꢀ
methylbenzonitrile and 4ꢀmethoxybenzonitrile were firstly
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Page 8 of 11
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
Figure 8. The proposed mechanism for transfer hydrogenation of nitriles to primary amines and imines
as 2ꢀphenylacetonitrile and nꢀpentanenitrile, even 2ꢀ(4ꢀ
chlorophenyl) acetonitrile underwent the transfer hydrogenaꢀ
tion successfully, affording the desired benzylamine products
in excellent yields (Table 3, entries 8ꢀ10). Similarly, these
aliphatic nitriles could also be hydrogenated to produce the
corresponding imines with more than 80% selectivities (Table
3, entries 8ꢀ10). Interestingly, the Co@NCꢀ900 only catalyzed
the transfer hydrogenation of one C≡N group in terephthaloꢀ
nitrile, giving the corresponding benzylamine and imine prodꢀ
uct in 90% and 91% selectivities, respectively (Table 3, entry
11).
tion of basic sites was decreased with an increase in isopropaꢀ
nol volume, so the asꢀgenerated primary amine V could conꢀ
trollably attack the primary imine intermediate III to form the
intermediate VI (Figure 8, VI), followed by liberating a diaꢀ
mine (Figure 8, VII) with the regeneration of the catalysts
(Figure 8, I). Finally, NH3 was liberated from the diamine to
generate the desired imine products (Figure 8, VIII).[34bꢀd, 35]
CONCLUSION
In summary, we have developed an efficient MOFꢀderived
Co@NC catalyst system for the controllable transfer hydroꢀ
genation of nitriles to generate primary amines or imines with
a perfect switch. The Co@NC catalysts, which were prepared
by employing an Nꢀcontaining CoꢀMOF as the sacrificial temꢀ
plate, were proved to be highly active in the baseꢀfree transfer
hydrogenation of a variety of nitriles to generate their correꢀ
sponding primary amines or imines with highly controllable
selectivities by using isopropanol as protonꢀdonor. Further, the
catalysts exhibited good recyclability without any loss in conꢀ
version and selectivity even up to four runs. Moreover, the
proposed mechanism indicated the concentration of the Nꢀ
derived basic sites played the key role in giving the catalysts a
perfect switch of the selectivity by controlling the concentraꢀ
tion of the primary imine intermediate. The controllable selecꢀ
tivity, combining with the high efficiency, good compatibility
and recyclability as well as mild reaction conditions, makes
this system an attractive alternative pathway for transfer hyꢀ
drogenations of nitriles to produce primary amines vs imines,
showing potential application in chemical industry.
On the basis of the above results, we proposed a possible
reaction mechanism with respect to the transfer hydrogenation
of nitriles to controllably produce amines and imines. In this
system, no base additive was added. So we speculated that the
Nꢀderived basic sites (confirmed by CO2ꢀTPD) on the cataꢀ
lysts played a similar role as the reported base additives,
which could facilitate the proton transfer to control the conꢀ
version of transfer hydrogenation reaction.28 Moreover, these
Nꢀderived basic sites were not only responsible for protecting
the catalyst from deactivation by inhibiting the formation of
polyamine or preventing the product stack on the surface of
catalysts,32ꢀ33 but also in charge of adjusting the concentrations
of intermediates and thus controlling the selectivities of
amines and imines.28 The plausible reaction mechanism is
exhibited in Figure 8. Firstly, the nitriles and isopropanol were
adsorbed on the catalysts. Then the basic sites of the catalysts
helped to release the protons from isopropanol and deliver the
free protons to the activated nitrile molecules (Figure 8, II),
generating the corresponding primary imine intermediate III
(Figure 8, III), which was very active and could be further
hydrogenated to produce a primary amine V (Figure 8, IVꢀV).
ASSOCIATED CONTENT
Additional XRD pattern, nitrogen adsorption/desorption isotherms
and CO2ꢀTPD profile, etc. This material is available free of charge
via the Internet at http://pubs.acs.org.
34
At this moment, if the concentration of basic sites was high
enough, no other products would be produced, and thus the
main products were the primary amines. Nevertheless, if the
concentration of basic sites was too low to control the concenꢀ
tration of the intermediate, imines would be the main product
as we mentioned above.33 In the present system, the concentraꢀ
AUTHOR INFORMATION
Corresponding Author
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ACS Catalysis
113ꢀ117. (c) Huang, Y.; Sachtler, W. M. H. Appl. Catal. A: Gen.
1999, 182, 365ꢀ378.
(6) (a) ZereceroꢀSilva, P.; JimenezꢀSolar, I.; Crestani, M. G.; Aréꢀ
*Eꢀmail: cekshen@scut.edu.cn (K. Shen).
*Eꢀmail: liyw@scut.edu.cn (Y. Li).
Notes
1
2
3
4
5
6
7
8
valo, A.; BarriosꢀFrancisco, R.; García. J. J. Appl Catal A: Gen
2009 363, 230ꢀ234. (b) Srimani, D.; Feller, M.; BenꢀDavid, Y.;
Milstein, D. Chem. Commun. 2012 48, 11853ꢀ11855. (c) Raseroꢀ
Almansa, A. M.; Corma, A.; lglesias, M.; Sánchez, F. Green
Chem. 2014 16, 3522ꢀ3527.
(7) Werkmeister, S.; Junge, K.; Wendt, B.; Spannenberg, A.; Jiao,
H.; Bornschein, C.; Beller, M. Chem. Eur. J. 2014 20, 4227ꢀ4231.
(8) (a) Addis, D.; Enthaler, S.; Junge, K.; Wendt, B.; Beller, M.
Tetrahedron Lett. 2009 50, 3654ꢀ3656. (b) Ortizꢀ Cervantes, C.;
Iyañez, I.; García, J. J. J. Phys. Org. Chem. 2012 25, 902ꢀ907. (c)
Huang, Y.; Adeeva, V.; Sachtler, W. M. H. Appl. Catal. A: Gen.
2000 196, 73ꢀ85. (d) Werkmeister, S.; Junge, K.; Beller, M. Org.
Process Res. Dev. 2014 18, 289ꢀ302. (e) Segobia, D. J.; Trasarti,
A. F.; Apesteguía, C. R. Appl. Catal. A: Gen. 2012 445, 69ꢀ75.
.
The authors declare no competing financial interest
,
,
ACKNOWLEDGMENT
,
We thank the Scientific Research Fund of Chemical Synthesis and
Pollution Control Key Laboratory of Sichuan Province
(CSPC2015ꢀ1ꢀ2), and Scientific Research Fund of China West
Normal University (412553), National Natural Science Foundaꢀ
tion of China (21322606, 21436005, and 21576095), China Postꢀ
doctoral Science Foundation (2015M572323, 2016T90785), Funꢀ
damental Research Funds for the Central Universities
(2015ZM045, 2015ZP002, and 2015PT004) and Guangdong Natꢀ
ural Science Foundation (2014A030310445, 2016A050502004
and 2013B090500027) for financial support.
,
9
,
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
,
,
,
,
(9) Zoran, A., Khodzhaev, O.; Sasson, Y. J. Chem. Soc. 1994
,
2239ꢀ2240.
(10) (a) Horn, S.; Gandolfi, C.; Albrecht, M. Eur. J. Inorg. Chem.
2011 18, 2863ꢀ2868. (b) Palmer, M. J.; Wills, M. Tetrahedron:
Asymmetry 1999 10, 2045ꢀ2061.
(11) (a) Kumbhar, P. S.; SanchezꢀValente, J.; Millet, J. M. M.;
Figueras, F. J. Catal. 2000 191, 467ꢀ473. (b) Auer, S. M.; Grunꢀ
waldt, J. D.; Köppel, R. A.; Baiker, A. J. Mol. Catal. A: Chem.
1999 139, 305ꢀ313.
REFERENCES
,
(1) (a) Hayes, K. Appl. Catal. A, 2001
M.; Sugiono, E.; Schoepke, F. R. Synlett, 2010, 852ꢀ865. (c) Mülꢀ
ler, T. E.; Beller, M. Chem. Rev. 1998 98, 675ꢀ703. (d) Seayad, J.;
Tillack, A.; Hartung, C. G.; Beller, M. Adv. Synth. Catal. 2002
344, 795ꢀ813. (e) Tang, W.; Zhang, X. Chem. Rev. 2003 103
3029ꢀ3069. (f) Pohlki, F.; Doye, S. Chem. Soc. Rev. 2003
, 221, 187ꢀ195. (b) Rueping,
,
,
,
,
,
,
,
,
32, 104ꢀ
(12) Kadyrov, R.; Riermeier, T. H. Angew. Chem., Int. ed. 2003
42, 5472ꢀ5474.
,
114. (g) Blaser, H. U.; Spindler, F. Handbook of Homogeneous
Hydrogenation, WileyꢀVCH, Weinheim, 2007. (h) Severin, R.;
(13) (a) Uematsu, N.; Fujii, A.; Hashiguchi, S.; Ikariya, T.;
Noyori, R. J. Am. Chem. Soc. 1996 118, 4916ꢀ4917. (b) Haddenꢀ
ham, D.; Pasumansky, L.; DeSoto, J.; Singaram, S. E. B. J. Org.
Chem. 2009 74, 1964ꢀ1970. (c) Bornschein, C.; Werkmeister, S.;
Junge, K.; Beller, M. New J. Chem. 2013 37, 2061ꢀ2065. (d) Das,
S.; Wendt, B.; Mçller, K.; Junge, K.; Beller, M. Angew. Chem.,
Int. Ed. 2012 51, 1662ꢀ1666. (e) Khurana, J. M.; Kukreja, G.
Synthetic Commun. 2002 32, 1265ꢀ1269. (f) Saavedra, J. Z.;
Resendez, A.; Rovira, A.; Eagon, S.; Haddenham, D.; Singaram,
B. J. Org. Chem. 2012 77, 221ꢀ228.
(14) (a) Wang, F.; Shi, R.; Liu, Z. Q.; Shang, P. J.; Pang, X.; Shen,
S.; Feng, Z.; Li, C.; Shen, W. ACS Catal. 2013 , 890ꢀ894; (b)
Salam, N.; Kundu, S. K.; Roy, A. S.; Mondal, P.; Ghosh, K.;
Bhaumik, A.; Islam, S. M. Dalton Trans. 2014 43, 7057ꢀ7068.
(15) (a) Watanabe, Y.; Ohta, T.; Tsuji, Y.; Hiyoshi, T.; Tsuji, Y.
Bull. Chem. Soc. Jpn. 1984 57, 2440ꢀ2446. (b) Imai, H.; Nishiguꢀ
chi, T.; Fukuzumi, K. Chem. Lett. 1976, 655ꢀ660. (c) Shen, K.;
Chen, X.; Chen, J.; Li, Y. ACS Catal. 2016 , 5887ꢀ5903.
(16) Mizushima, E.; Yamaguchi, M.; Yamagishi, T. J. Mol. Catal.
A: Chem. 1999 148, 69ꢀ75.
(17) (a)VilchesꢀHerrera, M.; Werkmeister, S.; Junge, K.; Börner,
A.; Beller, M. Catal. Sci. Technol. 2014 , 629ꢀ632; (b) Das, S.;
Doye, S. Chem. Soc. Rev
Hultzsch, K. C.; Yus, M.; Foubelo, F.; Tada, M. Chem. Soc. Rev.
2008 108, 3795ꢀ3892. (j) Nugent, T. C.; EIꢀShazly, M. Adv.
Synth. Catal. 2010 352, 753ꢀ819.
(2) (a) Enthaler, S.; Junge, K.; Addis, D.; Erre, G.; Beller, M.
ChemSusChem 2008 , 1006ꢀ1010. (b) Enthaler, S.; Addis, D.;
Junge, K.; Erre, G.; Beller, M. Chem. Eur. J. 2008 14, 9491ꢀ9494;
(c) Li, X.; Zeeland, R. V.; MaligalꢀGanesh, R. V.; Pei, Y.; Power,
G.; Stanley, L.; Huang W. ACS Catal. 2016 , 6324; (d) Choi, K.
M.; Na, K.; Somorjai, G. A.; Yaghi O. M. J. Am. Chem. Soc.
2015 137, 7810; (e) Li, X.; Goh, T. W.; Li, L.; Xiao, C., Guo, Z.;
Zeng, X. C.; Huang, W. ACS Catal. 2016 , 3461; (f) Li, X.;
Guo, Z.; Xiao, C.; Goh, T. W.; Tesfagaber, D.; Huang, W. ACS
Catal. 2014 , 3490.
(3) (a) Huang, Y.; Sachtler, W. M. H. J. Catal. 1999
225. (b) Hegedús, L.; Máthe, T. Appl. Catal. A: Gen. 2005
209ꢀ215. (c) Hegedűs, L.; Máthé, T.; Kárpáti, T. Appl. Catal. A:
Gen. 2008 349, 40ꢀ45. (d) Maki, S.; Okawa, M.; Makii, T.; Hiraꢀ
no, T.; Niwa, H. Tetrahedron Lett. 2003 44, 3717ꢀ3721. (e) Ikaꢀ
. 2007, 36, 1407ꢀ1420. (i) Müller, T. E.;
,
,
,
,
,
,
1
,
,
,
,
, 6
,
,
,
,
3
,
, 6
,
,
, 4
,
188, 215ꢀ
296
,
,
,
,
, 6
,
,
,
wa, T.; Fujita, Y.; Mizusaki, T.; Betsuin, S.; Takamatsu, H.;
Maegawa, T.; Monguchi, Y.; Sajiki, H. Org. Biomol. Chem. 2012,
10, 293ꢀ304. (f) Chatterjee, M.; Kawanami, H.; Sato, M.; Ishizaka,
,
4
Wendt, B.; Mçller, K.; Junge, K.; Beller; M. Angew. Chem. Int. Ed.
2012, 51, 1662–1666. (c) Khurana, J. M.; Kukreja, G. Synthetic
Commu., 2002, 32, 1265ꢀ1269.
T.; Yokoyama, T.; Suzuki, T. Green Chem. 2010
Maegawa, T.; Fujita, Y.; Sakurai, A.; Akashi, A.; Sato, M.; Oono,
K.; Sajiki, H. Chem. Pharm. Bull. 2007 55, 837ꢀ839.
(4) (a) Toti, A.; Frediani, P.; Salvini, A.; Rosi, L.; Giolli, C.;
Giannelli, C. Comptes Rendus Chimie 2004 , 769ꢀ772. (b) Li, T.;
Bergner, I.; Nipa, F. H.; ZimmerꢀDe, M. I.; Song, D.; Morris, R.
H. Organometallics, 2007 26, 5940ꢀ5949. (c) Grey, R. A.; Pez, G.
P.; Wallo, A. J. Am. Chem. Soc. 1981 103, 7536ꢀ7542. (d) Pez, G.
P.; Grey, R. A.; Corsi, J. J. Am. Chem. Soc. 1981 103, 7520ꢀ7528.
(e) Takemoto, S.; Kawamura, H.; Yamada, Y.; Okada, T.; Ono,
A.; Yoshikawa, E.; Mizobe, Y.; Hidai, M. Organometallics, 2002
21, 3897ꢀ3904. (f) Xie, X.; Liotta, C. L.; Eckert, C. A. Ind. Eng.
Chem. Res. 2004 43, 7907ꢀ7911. (g) Werkmeister, S.; Junge, K.;
Beller, M. Org. Process Res. Dev. 2014, 18, 289ꢀ302. (h) Kusaka,
, 12, 87ꢀ93. (g)
,
(18) (a) Lee, J. Y.; Olson, D. H.; Pan, L.; Emge, T. J.; Li, J. Adv.
Funct. Mater. 2007
Canepa, P.; Gong, Q.; Li, J.; Thonhauser, T.; Chabal, Y. J. Chem.
Mater. 2012 24, 3153ꢀ3170. (c) Dybtsev, D. N.; Chun, H.; Kim,
K. Angew. Chem., Int. Ed. 2004 43, 5033ꢀ5036.
(19) Shen, K.; Chen, L.; Long, J.; Zhong, W.; Li, Y. ACS Catal.
2015 , 5264ꢀ5271.
(20) (a) Long, J.; Zhou, Y.; Li, Y. Chem. Commun. 2015
, 17, 1255ꢀ1262. (b) Tan, K., Nijem, N.;
,
7
,
,
,
,
,
,
5
,
51
,
,
,
2331ꢀ2334. (b) Long, J.; Zhou, Y.; Li, Y. Chinese J. Catal. 2016
37, 955–962.
(21) Nam, K. M.; Shim, J. H.; Ki, H.; Choi, S. I.; Lee, G.; Jang, J.
,
K.; Jo, Y.; Jung, M. H.; Song, H.; Park, J. T. Angew. Chem., Int.
H.; Hara, Y.; Onuki, M.; Akai, T.; Okuda, M. J. Catal. 1996, 161,
96ꢀ106.
Ed. 2008
, 47, 9504ꢀ9508.
(22) Tang, J.; Salunkhe, R. R.; Liu, J.; Torad, N. L.; Imura, M.;
Furukawa, S.; Yamauchi, Y. J. Am. Chem. Soc. 2015, 137, 1572ꢀ
1580.
(5) (a) Rajesh, K.; Dudle, B.; Blacque, O.; Berke, H. Adv. Synth.
Catal. 2011 353, 1479ꢀ1484. (b) Giannandrea, R.; Mastrorilli, P.;
Zaccaria, G.; Nobile, C. F. J. Mol. Catal. A: Chem. 1996 109
,
,
,
ACS Paragon Plus Environment

ACS Catalysis
Page 10 of 11
(23) Biesingera, M. C.; Payne, B. P.; Grosvenor, A. P.; Lau, L. W.
M.; Gerson, A. R.; Smart, R. C. Appl. Surf. Sci. 2011, 257, 2717ꢀ
2730.
1
2
3
4
(24) (a) Das, R.; Pachfule, P.; Banerjee, R.; Poddar, P. Nanoscale
2012 , 591ꢀ599. (b) Zhong, W.; Liu, H.; Bai, C.; Liao, S.; Li, Y.
ACS Catal 2015 , 1850ꢀ1856.
,
4
.
, 5
5
(25) (a) Souza, F. G.; Richa, P.; Siervo, A.; Oliveira, G. E.; Roꢀ
drigues, C. H. M.; Nele, M.; Pinto, J. C. Macromol. Mater. Eng.
6
7
8
9
2008
Mater. Chem. A, 2016
(26) (a) Stevens, J. S.; Byard, S. J.; Muryn, C. A.; Schroeder, S. L.
M. J. Phys. Chem. B 2010 114, 13961ꢀ13969. (b) Stevens, J. S.;
Byard, S. J.; Schroeder, S. L. M. J. Pharm. Sci. 2010 99, 4453ꢀ
,
239, 675ꢀ683. (b) Long, J.; Shen, K.; Chen, L.; Li, Y. J.
,
4, 10254ꢀ10262.
,
,
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
,
4457. (c) Shibata, M.; Kimura, Y.; Yaginuma, D. Polymer 2004
45, 7571ꢀ7577.
,
(27) (a) Li, X. L.; Wang, H. L.; Robinson, J. T.; Sanchez, H.; Diꢀ
ankov, G.; Dai, H. J. J. Am. Chem. Soc. 2009 131, 15939ꢀ15944.
(b) Chen, L.; Xu, C.; Du, R.; Mao, Y.; Xue, C.; Chen, L.; Qu, L.;
Zhang, J.; Yi, T. J. Mater. Chem. A 2015 , 5617ꢀ5627. (c) Lefeꢀ
,
,
3
vre, M.; Proietti, E.; Jaouen, F.; Dodelet, J. P. Science 2009, 324,
71ꢀ74.
(28) (a) Dong, Z. R.; Li, Y. Y.; Chen, J. S.; Li, B. Z.; Xing, Y.;
Gao, J. X. Org. Lett 2005 , 1043ꢀ1045. (b) Noyori, R.; Hashiguꢀ
chi, S. Acc. Chem. Res. 1997 30, 97ꢀ102. (c) Long, J.; Yin, B.; Li,
Y.; Zhang, L. AIChE J. 2014 60, 3565ꢀ3576. (d) Noyori, R.;
.
, 7
,
,
Yamakawa, M.; Hashiguchi, S. J. Org. Chem. 2001, 66, 7931ꢀ
7944.
(29) (a)Rosi, N. L.; Kim, J.; Eddaoudi, M.; Chen, B.; O’Keeffe,
M.; Yaghi, O. M. J. Am. Chem. Soc. 2005 127, 1504ꢀ1518. (b)
Miles, D. O.; Jiang, D.; Burrows, A. D.; Halls, J. E.; Marken, F.
Electrochem. Commun 2013 27, 9–13
(30) (a) Banerjee, R.; Phan, A.; Wang, B.; Knobler, C.; Furukawa,
H.; O'Keeffe, M. Science 2008 319, 939ꢀ943. (b) Qian, J.; Sun, F.;
Qin, L. Mater. Lett. 2012 82, 220ꢀ223.
(31) Brieger, G.; Nestrick, T. J. Chem. Rev. 1974
(32) Allgeier, A. M.; Duch, M. W. Chemical industries, Dekker,
2001 Vol. 82, pp 229.
,
.
,
,
,
,
74, 567ꢀ580.
,
.
(33)ThomasꢀPryor, S. N.; Manz, T. A.; Liu, Z.; Koch, T. A.;
Sengupta, S. K.; Delgass, W. N. Chemical Industries, Dekker,
New York
, 1998, Vol. 75, pp. 195.
(34) (a) Srimani, D.; Feller, M.; David, Y. B.; Milstein, D. Chem.
Commun. 2012
,
48, 11853ꢀ11855. (b) AlꢀHmoud, L.; Jones, C. W.
J. Catal 2013
.
, 301, 116ꢀ124. (c) Reguillo, R.; Grellier, M.; Vauꢀ
travers, N.; Vendier, L. J. Am. Chem. Soc. 2010, 132, 7854ꢀ7855.
(35) Gnanaprakasam, B.; Zhang, J.; Milstein, D. Angew. Chem., Int.
Ed. 2010, 49, 1468ꢀ1471.
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