Post-functionalized iridium-Zr-MOF as a promising recyclable catalyst for the hydrogenation of aromatics

Article abstract of DOI:10.1039/c4gc00581c

The multifunctional heterogeneous catalyst iridium-Zr-based MOF is able to effectively catalyze the hydrogenation of aromatic compounds in high yields under mild conditions. The catalyst was found to be highly active and reusable, giving similar reactivity and selectivity after at least five catalytic uses. This journal is the Partner Organisations 2014.

Full text of DOI:10.1039/c4gc00581c

Green Chemistry
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Post-functionalized iridium–Zr-MOF
as a promising recyclable catalyst for
the hydrogenation of aromatics†
Cite this: Green Chem., 2014, 16,
522
3
a
b
a
c
Antonia M. Rasero-Almansa, Avelino Corma, Marta Iglesias* and Félix Sánchez*
Received 2nd April 2014,
Accepted 1st May 2014
The multifunctional heterogeneous catalyst iridium–Zr-based MOF is able to effectively catalyze the
hydrogenation of aromatic compounds in high yields under mild conditions. The catalyst was found to be
highly active and reusable, giving similar reactivity and selectivity after at least five catalytic uses.
DOI: 10.1039/c4gc00581c
www.rsc.org/greenchem
an important industrial catalytic transformation, particularly
for the production of cleaner-burning, low-aromatic diesel
Zr-based MOF (UiO66–NH ) was selected as a support owing to fuels. In this paper we report the catalytic activity of iridium
Introduction
4
a
2
its many outstanding physical and chemical properties. It has complexes immobilized on functionalized Zr-MOF in the
a large specific surface area and pore size as well as good hydrogenation of arenes. Moreover, the Ir–Zr-MOF can be
chemical resistance to water and organic solvents, a highly recycled via centrifugation and used at least for 5 cycles.
desirable and most promising combination for catalytic appli-
1
cations. These highly stable new materials, after the adequate
post-synthetic modification, can act as heterogeneous catalysts
that combine the properties of soluble organometallic com-
plexes with those of the MOF as a support. Recently we UiO66–NH
Results and discussion
1
1
was selected since the presence of NH groups
2
2
described that post-functionalized rhodium and iridium–Zr- in the linker (2-aminoterephthalic acid) allows the functionali-
based MOFs can be applied as multifunctional catalysts for zation of the material by conventional reactions, and functio-
2
one-pot and cascade reactions .
nalized-Zr-MOFs can be prepared according to well established
possesses Lewis acid sites
other catalytic processes, we shifted our attention to the appli- (zirconium), and the introduction of metal complexes on
cation of Ir–Zr-MOF-supported catalysts for other reactions. UiO66–NH gives rise to a bifunctional catalyst which com-
Among such processes, aromatic hydrogenation to form cyclo- bines acidity and metallic sites capable of hydrogenation/dehy-
hexane derivatives is one of the most important steps from an drogenation. UiO66–NH was prepared by mixing ZrCl and
in DMF, crystallization at 120 °C for 12–24 h, acti-
chemical industry, for clean diesel fuel generation, and the vation by DMF exchange with tetrahydrofurane and drying
In order to extend the benefits of the Zr-based MOFs to procedures. In addition, UiO66–NH
2
2
2
4
3
,4
environment preservation standpoint,
in both the petro- BDC-NH
2
2
−1
pharmaceutical industry, for safe drug synthesis. The field is under vacuum (BET surface area = 800 m g ). The resulting
5
also of interest in relation to hydrogen storage. The hydrogen- Zr–NH
-MOF was suspended in CH
Cl
(Scheme 1) at room temperature for 24 h. Mean-
molecular cata- while, iridium complexation by the imino-pincer ligand was
and treated with the
2
2
2
2
,12
ation of benzene and arenes is generally accomplished using aldehyde
heterogeneous catalysts almost exclusively,
lysts immobilized on heterogeneous surfaces, supported
nanoparticle, or soluble nanoparticle systems, sometimes
inadvertently derived from molecular precursors, represents
4
a,6
7
8
9
1
0
a
Inst. Ciencia de Materiales de Madrid, CSIC, C/Sor Juana Inés de la Cruz, n° 3,
2
8049 Madrid, Spain. E-mail: marta.iglesias@icmm.csic.es
b
Inst. Tecnología Química, UPV-CSIC, Avda. de los Naranjos, s/n, 46022 Valencia,
Spain. E-mail: acorma@itq.upv.es
c
Inst. Química Orgánica General CSIC, C/ Juan de la Cierva, n° 3, 28006 Madrid,
Spain. E-mail: felix-iqo@iqog.csic.es
†
Electronic supplementary information (ESI) available: Details of characteriz-
ation. See DOI: 10.1039/c4gc00581c
Scheme 1 Preparation of iridium–Zr-MOF.
3522 | Green Chem., 2014, 16, 3522–3527
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We selected aniline as our model compound to explore the
Zr–[IrL] catalyzed aromatic hydrogenation reaction, the selec-
tive conversion to cyclohexanamine, in standard conditions
with ethanol as a solvent, was 100% after 10 h. However, when
temperature increased to 90 °C alkylation of amine to N-ethyl-
cyclohexanamine was the major product. At this temperature,
reaction in isopropanol or 2-butanol also resulted in N-isopro-
2,20
pylcyclohexanamine or N-(pentan-2-yl)cyclohexanamine,
eliminating this secondary reaction we can use t-butanol as a
solvent or 60 °C temperature and 6 bar H
for
2
.
Fig. 1 SEM (a) and TEM (b) images for UiO66–NH
2
–[LIr].
Zr–[IrL] was also tested in the hydrogenation of a series of
other representative monosubstituted benzenes with electron
withdrawing or donating groups. Substrates with electron
donating groups are hydrogenated faster than those with elec-
tron withdrawing groups (Table 1 and Fig. 2). We found that
2
almost quantitative as we have previously described; details
for preparation and characterization can be found in the ESI.†
The modified samples show thermal stabilities comparable to
that of UiO66–NH2 with decomposition temperatures near
3
50 °C in air. All steps occur without apparently losing the
a
Table 1 Hydrogenation of aromatic substrates
framework integrity (XRD patterns in Fig. S2†).
b
d
Cat.
mol%)
Conv. (%)
(h)
TOF
−1
N adsorption results further confirmed the stability of the
2
(
Substrate
Product
(h
)
porous structure after metal doping (ESI Fig. S6†). SEM and
TEM micrographs showed the materials have preserved their
structure (Fig. 1).
c
1
2
3
[IrL] (1)
100 (8)
42
85
80
[ZIrL] (0.20)
ZIrL] (0.20)
85 (5)
Iridium-MOF catalyst for hydrogenation of aromatics
98 (10)
The efficient synthesis of cyclohexane derivatives via the cataly-
tic hydrogenation of aromatic compounds is of both scientific
and industrial importance. However, the complete hydrogen-
ation of aromatics still requires highly energetic (>100 °C) and
90 (10)
100 (5)
49 (6)
4
5
6
[ZIrL] (0.20)
[ZIrL] (0.20)
[ZIrL] (0.20)
98
60
dangerous reaction conditions (50 atm H ) due to the lack of
2
efficient catalysts. Recent publications suggest that palla-
1
3
14
15
16
17
dium, ruthenium, rhodium, iridium and nickel may
be used to achieve the hydrogenation of aromatic compounds
under milder conditions. The utilization of platinum-based
65 (24)
85 (6)
110
1
8
catalysts has been less investigated.
On the other hand, it is well known that Lewis acids can
1
9
7
8
9
1
[ZIrL] (0.20)
[ZIrL] (0.20)
90 (5)
235
10
8
activate aromatic compounds and a sequential step is hydro-
genation by hydrogen atoms which were activated by the metal
as depicted in Scheme 2. These two types of activation could
work cooperatively, resulting in high activity for producing
cyclohexane derivatives. Our bifunctional Zr–[IrL]-catalyst has
zirconium as Lewis acid and iridium which can act as the
active metal. Herein we report the highly efficient catalytic
hydrogenation of aromatic compounds, under mild conditions
90 (22)
75 (24)
+
c
[ZIrL] (0.20)
0
[ZIrL] (0.20)
Traces (20)
0 (24)
—
(
in ethanol at 6 bar of H and 60–90 °C) by simultaneous acti-
2
vation of molecular hydrogen and the aromatic substrate with 11 [ZIrL] (0.20)
iridium and zirconium as Lewis acid respectively.
12
12
[ZIrL] (0.20)
67 + 17 (19) n.d.
a
2
Reaction conditions: solvent: ethanol or isopropanol, T: 60 °C, PH : 6
b
c
bar. Based on Ir. Reaction in t-butanol at 90 °C, reaction in
d
Scheme 2 General reaction pathway for the hydrogenation of aromatic isopropanol (90 °C) yields 60% of N-alkylated product. mmol subs
mmol− cat. h
1
−1
.
compounds.
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cyano and nitro groups attached to an aromatic ring (Table 2).
Thus, olefinic double bonds of styrene and α-methylstyrene
were fully converted to ethylbenzene and isopropylbenzene
respectively; also carbonyl compounds as benzaldehyde or
acetophenone yield the corresponding alcohols, and benzo-
nitrile or nitrobenzene the corresponding amines; in all cases
these groups were hydrogenated before the reduction of arene
was initiated.
Recycling experiments and heterogeneity of catalyst
After the hydrogenation reaction, Zr–[IrL] was separated from
the reaction mixture by filtration or centrifugation, thoroughly
washed with ethanol and reutilized as a catalyst in subsequent
runs under identical reaction conditions. The results included
in Fig. 3a indicate that after the first cycle the activity slightly
decreased and then no efficiency loss was observed in the
arene hydrogenation for up to five runs. Moreover, the filtrate
solutions collected at the end of each catalytic run were ana-
lyzed by ICP-MS and in none of them Ir was detected, which
confirms the absence of iridium in the solution, whilst in
Fig. 2 Kinetic
hydrogenation.
profile
for
the
Zr–[IrL]-catalyzed
aromatic
Zr–[IrL] catalyzes the quantitative hydrogenation of aromatic
hydrocarbons such as toluene, and phenol which was reduced
to cyclohexanol with only traces of cyclohexanone detected as
well as ethyl benzoate (Table 1, entries 4, 6, and 7); styrene is
quickly reduced to ethylbenzene (Table 2, entry 1), which was
hydrogenated to ethylcyclohexane at 90 °C (Table 1, entry 8).
Nitrobenzene and benzonitrile were transformed to cyclohexyl-
amine and cyclohexylmethanamine respectively in good yield
and selectivity (Table 1, entries 3 and 9). Bromobenzene or
diethyl phthalate did not react under these reaction con-
ditions, even at 90 °C (Table 1, entries 10 and 11) while methyl
FT-IR spectra of the recovered solid the catalyst appears as a
−1
band at ∼2000 cm
Fig. S10†).
A control experiment was also performed to show that the
corresponding to the ν(Ir–H) bond
(
hydrogenation reactions are stopped by the removal of Ir–Zr-
MOF from the reaction solution (Fig. 3b). Moreover, they
provide easy separation and high reusability performance in
these reactions by keeping their stability against leaching
throughout the catalytic runs.
The characterization of the isolated samples from the fifth
catalytic run in the hydrogenation of aniline (using XRD, SEM
and TEM) reveals that (i) the crystallinity of the host UiO66
framework is mainly retained (Fig. 4) and (ii) there is some
bulk iridium formed within the framework of UiO66, at the
end of the fifth catalytic run (SEM and TEM images in Fig. 5
and 6). Higher SEM and TEM resolution for Ir–Zr-MOF crystal-
lites is difficult due to local damage by electron beams, which
cause distortion and movement.
2
-methoxybenzoate yields the corresponding cyclohexane car-
boxylate besides 20% of hydrogenolysis of the C–O bond
Table 1, entry 12). Comparing the soluble Ir-complexes, used
(
as reference catalysts (Table 1, entry 1), with the corresponding
supported on Zr–[IrL]-MOF, a considerable increase in the
reactivity was observed.
In order to determine the selectivity of different functional
groups against arenes, we explored the catalyzed-hydrogen-
ation for other unsaturated carbon bonds (CvC, CvO) and
a
Table 2 Hydrogenation experiments with Zr–[IrL]-catalysts
Recent studies have shown that metal–organic frameworks
are also to be considered as suitable host materials to con-
trolled growth of catalytic clusters or nanoparticles within
Entry
1
Substrate
Product
Conv. (%) (h)
100 (0.5)
TOF (h−
935
1
)
21
MOF cavities. To date it has already been demonstrated that
the zeolitic imidazole framework (ZIF-8 MOF) or MIL101(Cr)
can act as a suitable host material for Au, Ag, Ni, Ir and
2
100 (2)
325
22
23
24 25
3
4
100 (0.5)
1000
13
100 (24)
85 (2)
5
6
850
10
20 (24)
b
100 (20)
Fig. 3 (a) Recycling experiments for the catalyzed hydrogenation of
aniline and (b) hot filtration test for the hydrogenation of ethyl benzoate.
a
b
0
2
.2 mol% of catalyst based on Ir; PH : 2 bar, 40 °C. 90 °C.
3524 | Green Chem., 2014, 16, 3522–3527
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Fig. 7 PXRD for Zr–[LIr]-MOF: (a) recovered after the first run, (b)
recovered after the fifth run, (c) Zr-MOF-IrNPs after 6 bar H2 at 120 °C
Fig. 4 PXRD for a fresh catalyst and recovered after 1 run and 5 runs.
4
and (d) Zr-MOF-IrNPs obtained for reduction with NaBH .
The morphology of the different Ir–Zr-MOF samples was
examined by dynamic light scattering (DLS) (Fig. S11†), SEM
(
Fig. S12†) and TEM (Fig. S13†). The TEM images of material
obtained by reduction with NaBH4 or by hydrogenation at
20 °C show a lot of larger nanoparticles, and we have found
1
that they are inactive in hydrogenation reactions whilst TEM
images of recovered catalysts in operation conditions (60 °C/6
bar) show that most of the particles have a size similar to that
found in the fresh catalyst, which seems to corroborate the
view that the molecular structure of heterogenized complexes
was preserved, as could be also confirmed by FT-IR in which a
band corresponding to the Ir–H bond can be observed. The
presence of larger particles could be responsible for the
decrease of activity after the first cycle of reactions.
Fig. 5 SEM images of fresh (a) and recovered catalyst (b).
X-ray photoelectron spectroscopy (XPS) analysis was per-
formed on the fresh and recovered Zr–[LIr]-MOF solids. The
samples were kept in vacuum overnight prior to XPS measure-
ments. The spectra were calibrated with respect to the C1s
peaks in each sample. The survey scan XPS spectrum of the
Zr–[LIr]-MOF samples (Fig. S15†) shows the presence of
iridium in addition to the UiO66 framework elements (Zr, C,
N). XPS analysis showed N-1s (399.1 eV) and C-1s signals, the
2
3
latter comprising sp carbon (284.6 eV), and sp carbon neigh-
boring oxygen (287.9 eV). The XPS core level for the iridium
Fig. 6 TEM images of fresh (a) and recovered catalyst (b).
2
6
Pd
nanoparticles. The chemically robust Zr-based MOF
(
UiO66–NH ) also might result in a host matrix to stabilize
2
guest iridium nanoparticles (IrNPs).
We have reduced the Zr–[LIr]-MOF with NaBH (ethanol at
4
2
73 K for 2 h) or H (6 bar, 120 °C) in order to obtain nano-
2
particles of iridium supported on the Zr-MOF (Zr-MOF–IrNPs)
and we have found that PXRD analysis (Fig. 7) shows the
typical reflections of UiO66–NH , which confirm the stability
2
of the support under the chosen conditions, but reduced cata-
lysts were not active for hydrogenation of aniline and any
product formation was not observed after 24 h; and as a conse-
quence when the hydrogenation of aniline was performed with
Zr–[LIr]-MOF at 120 °C, recycling is not possible because the
activity decreases considerably after the first run.
Fig. 8 XPS Ir(4f) region for the original catalyst and recovered after
reaction.
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(
Ir(4f) region) showed no difference in peak positions between times, dried at 80 °C for 12 h and reused. The Zr-MOF–LIr
the original catalyst and the solid recovered from the reaction catalyst showed consistent activity for four cycles.
peaks at 64.8 and 62.1 eV, readily assigned to Ir4f7/2 and Ir4f5/2
(
)
δ+
27
indicating the Ir oxidation state in the samples (Fig. 8).
The hot filtration test of Zr-MOF–LIr catalyst
A mixture of Zr-MOF–LIr (6.7 mg, 7.0 × 10− mmol Ir), ethyl
benzoate (50 µL, 0.35 mmol), and ethanol (15 mL) was put
into a reactor (Autoclave Engineers) and was extensively stirred
4
Conclusions
(
ca. 1000 rpm) at 60 °C, 6 bar H for 0.5 h. The conversion was
2
The use of the iridium pincer complex active phase and
Zr-MOF as a support has allowed us to obtain a new catalyst
for the direct hydrogenation of aromatic compounds at low
temperatures and initial hydrogen pressures. These catalysts
are versatile and can be easily recycled with high conversion
efficiency for up to five cycles and represent an attractive
choice for green industrial and synthetic applications.
∼
20%. Then the solid catalyst was quickly separated after fil-
tration of the reactant mixtures. The liquid was kept at 60 °C
with extensive stirring for 24 h. The conversion was 35%. It
was found that the blank thermal reaction without any catalyst
for this reaction at 60 °C was ca. 8% (see Fig. 3).
Acknowledgements
Experimental
Reagents and materials
We thank the MINECO of Spain (project MAT2011-29020-C02-02),
Consolider-Ingenio 2010-(CSD-0050-MULTICAT). for financial
support. A.M.R.A. thanks MINECO for the FPI program.
Starting materials were purchased and used without further
purification from commercial suppliers (Sigma-Aldrich and
Alfa Aesar). Dried, distilled and deoxygenated solvents were
used.
Notes and references
1
(a) A. Schaate, P. Roy, A. Godt, J. Lippke, F. Waltz,
M. Wiebcke and P. Behrens, Chem. – Eur. J., 2011, 17, 6643–
Materials preparation
Synthesis of Zr-based metal–organic framework was performed
in a 250 mL round bottom flask using a procedure similar to
6651; (b) M. Kandiah, M. H. Nilsen, S. Usseglio,
S. Jakobsen, U. Olsbye, M. Tilset, Ch. Larabi,
1
1
that previously described. X-ray diffraction (Phillips X’Pert,
CuKα radiation) was used to confirm the expected crystalline
structure of the materials. All substances and reagents used
were commercially available and used as received. The reaction
and analytic methodology are given in ESI.† General consider-
ations and characterization methods are presented in ESI.†
E. A. Quadrelli, F. Bonino and K. P. Lillerud, Chem. Mater.,
2
010, 22, 6632–6640; (c) W. Morris, Ch. J. Doonan and
O. M. Yaghi, Inorg. Chem., 2011, 50, 6853–6855;
d) F. Vermoortele, R. Ameloot, A. Vimont, Ch. Serre and
D. De Vos, Chem. Commun., 2011, 47, 1521–1523;
e) S. J. Garibay and S. M. Cohen, Chem. Commun., 2010,
6, 7700–7702.
(
(
4
Catalytic measurements
2
3
(a) M. Pintado-Sierra, A. M. Rasero-Almansa, A. Corma,
M. Iglesias and F. Sánchez, J. Catal., 2013, 299, 137–145;
General procedure. Hydrogenation of aromatics was per-
formed in an Autoclave Engineers (100 mL). The reactants
were added to the suspension of catalysts (0.2 mol% based on
iridium) in ethanol (15–40 mL); the reactor was hermetically
(
b) A. M. Rasero-Almansa, A. Corma, M. Iglesias and
F. Sánchez, ChemCatChem, 2013, 5, 3092–3100.
B. R. James, Y. Wang and T. Q. Hu, Chem. Ind., 1996, 68, 423.
sealed, pressurized (6 bar H ) and heated (60 °C) under con-
tinuous stirring (ca. 1000 rpm). Small liquid aliquots
2
4 (a) A. Stanislaus and B. H. Cooper, Catal. Rev. Sci. Eng.,
994, 36, 75; (b) A. Corma, A. Martínez and V. J. Martínez-
1
(
≈100 µL) were taken. The progress of the reaction was moni-
Soria, J. Catal., 1997, 169, 480; (c) T. Enya, H. Suzuki,
T. Watanabe, T. Hirayama and Y. Hisamatsu, Environ. Sci.
Technol., 1997, 31, 2772.
tored by GC-MS (Fig. S16†).
In particular, hydrogenation of aniline (50 µL, 0.5 mmol)
−3
was performed with 10.5 mg (1.05 × 10 mmol Ir) of Zr-MOF–
LIr in 2-propanol (15 mL). The reaction mixture was filtered,
and the solvent was removed under reduced pressure to give
the crude product, pure for GC-MS. When the reaction is
carried out with 10 times more substrate, the reaction is com-
plete in 36 h.
5
6
T. Riis, E. F. Hagen, P. J. S. Vie and Ø. Ulleberg, in Hydrogen
Production and Storage-R&D Priorities and Gaps, Organiz-
ation for Economic Cooperation and Development (OECD)/
International Energy Agency (IEA) Publishers, Paris, 2006.
(a) S.-Ch. Qi, X.-Y. Wei, Z.-M. Zong and Y.-K. Wang,
RSC Adv., 2013, 3, 14219–14232; (b) P. Giannoccaro,
M. Gargano, A. Fanizzi, C. Ferragina and M. Aresta, Appl.
Catal., A, 2005, 284, 77.
The recycling of Zr-MOF–LIr
After completion of the reaction the catalyst was recovered by
separation of solid MOF-Ir from liquid after extensively centri-
fuging. The recovered catalyst was washed with ethanol three
7 (a) A. Corma, M. Iglesias and F. Sánchez, Catal. Lett., 1995,
32, 313–318; (b) M. S. Eisen and T. J. Iglesias, J. Am. Chem.
Soc., 1992, 114, 10358; (c) H. Gao and R. J. Angelici, J. Am.
3526 | Green Chem., 2014, 16, 3522–3527
This journal is © The Royal Society of Chemistry 2014

View Article Online
Green Chemistry
Paper
Chem. Soc., 1997, 119, 6937; (d) C. Bianchini, V. Dal Santo, 19 (a) H. Liu, T. Jiang, B. Han, S. Liang and Y. Zhou, Science,
A. Meli, S. Moneti, M. Moreno, W. Oberhauser, R. Psaro,
L. Sordelli and F. Vizza, Angew. Chem., Int. Ed., 2003, 42, 2636.
K. H. Park, K. Jang, H. J. Kim and S. U. Son, Angew. Chem.,
Int. Ed., 2007, 46, 1152.
(a) L. N. Lewis, Chem. Rev., 1993, 93, 2693; (b) J. Schulz,
A. Roucoux and H. Patin, Chem. – Eur. J., 2000, 6, 618.
2009, 326, 1250; (b) R. R. Deshmukh, J. W. Lee, U. S. Shin,
J. Y. Lee and C. E. Song, Angew. Chem., Int. Ed., 2008, 47,
8615; (c) K. Y. Koltunov, G. K. S. Prakash, G. Rasul and
G. A. Ohah, Tetrahedron, 2002, 58, 5423; (d) P. Tarakeshwar,
J. Y. Lee and K. S. Kim, J. Phys. Chem. A, 1998, 102, 2253;
(e) H. Ahn, Ch. P. Nicholas and T. J. Marks, Organometal-
lics, 2002, 21, 1788–1806.
8
9
1
0 (a) C. M. Hagen, L. Vieille-Petit, G. Laurenczy, G. Süss-Fink
and R. G. Finke, Organometallics, 2005, 24, 1819; 20 A. M. Rasero-Almansa, A. Corma, M. Iglesias and
(b) L. Vieille-Petit, G. Süss-Fink, B. Therrien, T. R. Ward,
F. Sánchez, ChemCatChem, 2014, DOI: 10.1002/
H. Stoeckli-Evans, G. Labat, L. Karmazin-Brelot, A. Neels,
cctc.201402101R1.
T. Bürgi, R. G. Finke and C. M. Hagen, Organometallics, 21 (a) J. Y. Lee, O. K. Farha, J. Roberts, K. A. Scheidt,
2
005, 24, 6104.
S. T. Nguyen and J. T. Hupp, Chem. Soc. Rev., 2009, 38,
1450; (b) D. Farrusseng, S. Aguado and C. Pinel, Angew.
Chem., Int. Ed., 2009, 48, 7502; (c) A. Corma, H. García and
F. X. L. Xamena, Chem. Rev., 2010, 110, 4606;
(d) S. T. Meek, J. A. Greathouse and M. D. Allendorf, Adv.
Mater., 2011, 23, 249; (e) H. L. Jiang and Q. Xu, Chem.
Commun., 2011, 47, 3351.
1
1 (a) J. H. Cavka, S. Jakobsen, U. Olsbye, N. Guillou,
C. Lamberti, S. Bordiga and K. P. Lillerud, J. Am. Chem.
Soc., 2008, 130, 13850; (b) M. Kim and S. M. Cohen, Cryst-
EngComm, 2012, 14, 4096.
2 M. Servalli, M. Ranocchiari and J. A. Van Bokhoven, Chem.
Commun., 2012, 48, 1904–1906.
1
1
3 (a) C. Zhao, Y. Kou, A. A. Lemonidou, X. Li and 22 (a) H. L. Jiang, B. Liu, T. Akita, M. Haruta, H. Sakurai and
J. A. Lercher, Angew. Chem., Int. Ed., 2009, 48, 3987;
b) J. Huang, Y. Jiang, N. Vegten, M. Hunger and A. Baiker,
J. Catal., 2011, 281, 352; (c) Y. Wang, J. Yao, H. Li, D. Su
and M. Antonietti, J. Am. Chem. Soc., 2011, 133, 2362;
Q. Xu, J. Am. Chem. Soc., 2009, 131, 11302; (b) D. Esken,
S. Turner, O. Lebedev, G. V. Tendeloo and R. A. Fischer,
Chem. Mater., 2010, 22, 6393; (c) G. Lu, S. Li, Z. Guo,
O. K. Farha, B. G. Hauser, X. Qi, Y. Wang, X. Wang, S. Han,
X. Liu, J. S. DuChene, H. Zhang, Q. Zhang, X. Chen, J. Ma,
S. C. J. Loo, W. D. Wei, Y. Yang, J. T. Hupp and F. Huo, Nat.
Chem., 2012, 4, 310.
(
(d) P. Makowski, R. D. Cakan, M. Antonietti, F. Goettmann
and M.-M. Titirici, Chem. Commun., 2008, 999.
4 (a) C. J. Boxwell, P. J. Dyson, D. J. Ellis and T. Welton, J. Am.
1
Chem. Soc., 2002, 124, 9334; (b) C. Hubert, A. Denicourt- 23 L. Jiang, T. Akita, T. Ishida, M. Haruta and Q. Xu, J. Am.
Nowicki, A. Roucoux, D. Landy, B. Leger, G. Crowyn and
E. Monflier, Chem. Commun., 2009, 1228.
Chem. Soc., 2011, 133, 1304.
24 P.-Z. Li, K. Aranishi and Q. Xu, Chem. Commun., 2012, 48,
1
5 (a) E. Bayram, J. C. Linehan, J. L. Fulton, J. A. S. Roberts,
3173.
N. K. Szymczak, T. D. Smurthwaite, S. Özkar, 25 M. Zahmakiran, Dalton Trans., 2012, 41, 12690.
M. Balasubramanian and R. G. Finke, J. Am. Chem. Soc., 26 J. Hermannsdörfer, M. Friedrich and R. Kempe, Chem. –
2
011, 133, 18889; (b) N. Yan, Y. Yuan, R. Dykeman, Y. Kou
Eur. J., 2013, 19, 13652–13657.
and P. J. Dyson, Angew. Chem., Int. Ed., 2010, 49, 5549; 27 (a) C. Wagner, W. M. Riggs, L. E. Davis, J. F. Moulder and
(
c) C. Hubert, A. Denicourt-Nowicki, P. Beaunier and
G. E. Muilenberg, Handbook of X-ray Photoelectron Spec-
troscopy, Physical Electronic Division, Perkin-Elmer, Eden
Prairie, MN, 1979, vol. 55; (b) C. Campos, C. Torres,
M. Oportus, M. A. Peña, J. L. G. Fierro and P. Reyes, Catal.
Today, 2013, 213, 93–100; (c) Ch. Wang, J.-L. Wang and
W. Lin, J. Am. Chem. Soc., 2012, 134, 19895–19908;
(d) U. Hintermair, S. W. Sheehan, A. R. Parent, D. H. Ess,
D. T. Richens, P. H. Vaccaro, G. W. Brudvig and
R. H. Crabtree, J. Am. Chem. Soc., 2013, 135, 10837–10851;
(e) L. L. Atanasoska, D. A. Cullen and R. T. Atanasoski,
J. Serb. Chem. Soc., 2013, 78, 1993–2005; M. Blanco,
P. Álvarez, C. Blanco, M. V. Jiménez, J. Fernández-Tornos,
J. J. Pérez-Torrente, L. A. Oro and R. Menéndez, ACS Catal.,
2013, 3, 1307–1317.
A. Roucoux, Green Chem., 2010, 12, 1167; (d) Y. Motoyama,
M. Takasaki, S.-H. Yoon, I. Mochida and H. Nagashima,
Org. Lett., 2009, 11, 5042; (e) T. Maegawa, A. Akashi,
K. Yaguchi, Y. Iwasaki, M. Shigetsura, Y. Monguchi and
H. Sajiki, Chem. – Eur. J., 2009, 15, 6953.
6 (a) E. Bayram, M. Zahmakiran, S. O. Zkar and R. G. Finke,
Langmuir, 2010, 26, 12455; (b) M. Zielinski, M. Pietrowski
and M. Wojciechowska, ChemCatChem, 2011, 3, 1653–1658.
7 (a) S. Toppinen, T.-K. Rantakyla, T. Salmi and J. Aittamaa,
Ind. Eng. Chem. Res., 1996, 35, 4424; (b) L. Lu, Z. Rong,
W. Du, S. Ma and S. Hu, ChemCatChem, 2009, 1, 369.
8 Zh. Guo, L. Hu, H.-h. Yu, X. Cao and H. Gu, RSC Adv.,
1
1
1
2
012, 2, 3477–3480.
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