Pd Nanoparticles Dispersed on ZrIV Organophosphonate: A Robust and Reusable Catalyst for Suzuki–Miyaura Cross-Coupling Reactions

Article abstract of DOI:10.1002/ejic.201701313

A mesoporous zirconium(IV) phosphonate was synthesized by the hydrothermal reaction of ZrOCl₂·8H₂O with a trisphosphonic acid ligand, mesityl-1,3,5-tris(methylenephosphonic acid). Treatment of the mesoporous Zr^IV phosphonate framework with Pd(OAc)₂ and subsequent reduction produced a nanocomposite where Pd nanoparticles of average size ca. 7–8 nm were found to be homogeneously and abundantly dispersed over the phosphonate framework. The composite acts as an efficient and reusable heterogeneous catalyst in the Suzuki–Miyaura cross coupling reaction of aryl bromides with aryl boronic acids.

Full text of DOI:10.1002/ejic.201701313

A Journal of
Accepted Article
Title: Pd nanoparticles dispersed on Zr(IV) organophosphonate: A
robust and reusable catalyst for Suzuki-Miyaura cross-coupling
reaction
Authors: Nayanmoni Gogoi, Suchibrata Borah, Shashank Mishra, and
Luis Cardenas
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To be cited as: Eur. J. Inorg. Chem. 10.1002/ejic.201701313
Link to VoR: http://dx.doi.org/10.1002/ejic.201701313

European Journal of Inorganic Chemistry
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Pd nanoparticles dispersed on Zr(IV) organophosphonate: A
robust and reusable catalyst for Suzuki-Miyaura cross-coupling
reaction
[a]
[b]
[b]
,[a]
Suchibrata Borah, Shashank Mishra, Luis Cardenas, and Nayanmoni Gogoi*
Abstract:
A
mesoporous zirconium(IV) phosphonate was
.8H with
application in industry.
synthesized by hydrothermal reaction of ZrOCl
2
2
O
a
MOFs are generally derived from polycarboxylate based
linkers and this can be primarily attributed to the availability of
structurally diverse metal carboxylate building blocks.[16]
Moreover, carboxylate ion form relatively weak coordination
bond with transition metal ions which allows reorganization of
the initial polymeric network to result into porous crystalline
frameworks. Isolation of crystalline product has greatly assisted
in the structural characterization and further advancement of
MOFs. However, labile metal-carboxylate linkages also facilitate
hydrolytic cleavage of carboxylate based MOFs and therefore
integrity of these frameworks have remained a primary concern
in their eventual application.[17-21] Phosphonic acids form
considerably strong bonds with metal ions as compared to
carboxylic acids. Thus, MOFs prepared by using phosphonic
acid based linkers offer better framework stability due to the
presence of stronger M-O-P bonds. Indeed, high valent metal
phosphonate based frameworks have such high stability that
they are even inert to very strong base and acid. For example
Clearfield and coworkers reported that framework structure of
trisphosphonic acid ligand, mesityl-1,3,5-tris(methylenephosphonic
acid). Treatment of the mesoporous Zr(IV) phosphonate framework
2
with Pd(OAc) and subsequent reduction produces a nanocomposite
where Pd nanoparticles of average size ~ 7-8 nm are found to be
homogeneously and abundantly dispersed over the phosphonate
framework. The present composite acts as an efficient and
reusuable heterogeneous catalyst in Suzuki-Miyaura cross coupling
reaction of aryl bromides with aryl boronic acids.
Introduction
In recent years, considerable attention has been devoted to
metal nanoparticles on account of their diverse applications in
catalysis.[
1-5]
Size dependent characteristics and easy surface
functionalization of metal nanoparticles fevered their proliferation
as selective and efficient catalyst.[6] Among the metal
nanoparticles, palladium nanoparticles are of particular interest
due to their relevance as catalyst in carbon-carbon formation
reactions.[7] In this regard, palladium nanoparticles supported
zirconium(IV) phenyl phosphonate remain intact even when
treated with fuming sulfuric acid for three days.[22] However, the
strong M-O-P bonds alleviate formation of poorly ordered
layered structure and this prevents accurate structural
characterization of high valent metal phosphonates. Moreover,
due to the polydentate nature of phosphonate group, the
resulting frameworks are comparatively denser and less porous
than carboxylate based frameworks.
[
8-
over heterogeneous materials such as carbon based materials,
1
0]
polymers,[11-12] boron nitride[13] and layered double hydroxide
have gained interest due to significant cost advantage and
[
14]
minimal environmental pollution. It is pertinent to note here that
tailoring the stability, activity and selectivity of metal nanoparticle
catalyst by chemical modification of the heterogeneous support
has remained one of the most pressing challenge in this area.
The ability to tailor the morphology as well as the chemical
environment of the voids renders metal organic frameworks
Interestingly a surfactant assisted sol-gel methodology has
been developed recently to assemble mesoporous metal
[23]
phosphonate frameworks with controlled mesoporosity.
Herein, surfactant micelle scaffolds act as lyotropic liquid
crystalline phase onto which oligomers from the condensation of
(
MOFs) as a promising new class of template for hosting
nanoparticles. A wide array of metallic nanoparticles e.g. Cu, Ru,
Pd, Au, Ag, Pt etc. have been immobilized on several porous
MOFs and many of them show excellent catalytic activity in
important organic transformations.[15] However, degradation of
the framework when highly reactive nanoparticles (e.g. Pd) are
loaded remains one of the most formidable challenges that need
to be addressed before such metals@MOF composites find
inorganic/organic
polymerization leading to the formation of an ordered
mesostructure. plethora of periodic mesoporous metal
precursors
condense
and
undergo
A
phosphonate materials has been assembled so far by using the
surfactant-assisted sol-gel method and their pore sizes can be
[24-32]
easily tailored by systematic variation of the surfactants.
It is
pertinent to note that studies related to the application of metal
phosphonate frameworks in catalysis are scarce and this can be
partly attributed to the robust nature of the frameworks which
[
[
a]
b]
Dr. Suchibrata Borah and Dr. Nayanmoni Gogoi
Department of Chemical Sciences
Tezpur University
[33-35]
make them unsuitable for many catalytic applications.
Nevertheless, immobilization of catalytically active metallic
nanoparticles over metal phosphonates based support offers a
unique opportunity to develop robust composites for eventual
catalytic application in industry. However, the studies focusing
on immobilization of metal nanoparticles on ordered
mesoporous metal phosphonate matrices have been largely
ignored so far and no metal@mesoporous metal phosphonate
composite has been reported till date.[
Napaam 784028, Assam, India
E-mail: ngogoi@tezu.ernet.in http://www.tezu.ernet.in/dcs/ngogoi
Dr. Shashank Mishra and Dr. Luis Cardenas
Université Claude Bernerd Lyon 1, Institut de recherches sur la
catalyse et l'environnement de Lyon (IRCELYON), CNRS-UMR
5256, 2 Avenue Albert Einstein, 69626, Villeurbanne, France.
36-38]
Supporting information for this article is given via a link at the end of
the document.
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European Journal of Inorganic Chemistry
10.1002/ejic.201701313
FULL PAPER
During this study a mesoporous Zr(IV) organophosphonate
is prepared by using a tris-phosphonic acid, mesityl-1,3,5-
Thermogravimetric analysis of both the pristine Zr(IV)
phosphonate framework MZrP and its nanocomposite
tris(methylenephosphonic acid) (H
6
L) and following the
2
Pd@MZrP were performed under N atmosphere to investigate
surfactant assisted sol-gel technique. The resulting mesoporous
Zr(IV) phosphonate was employed as a host matrix to support
Pd nanoparticles. Both the pristine mesoporous Zr(IV)
phosphonate and the Pd@mesoporous Zr(IV) phosphonate
composite were characterized by using various analytical,
spectroscopic, microscopic and textural analysis. Further, the
Pd@mesoporous Zr(IV) phosphonate composite acted as an
efficient and reusable catalyst in Suzuki-Miyaura cross coupling
reaction between aryl bromides and aryl boronic acids. The
synthesis, characterization of the pristine mesoporous Zr(IV)
phosphonate and the Pd@mesoporous Zr(IV) phosphonate
composite as well as the catalytic application of the composite
are described in the present chapter.
their thermal stabilities (Figure S2). In case of both MZrP and
Pd@MZrP, ~14% to 17% weight losses are observed between
28-127 °C and these can be attributed to the loss of surface
bound water molecules intercalated within interlayer spacings.
On heating beyond 127 °C, the pristine metal phosphonate
framework did not show any appreciable weight loss upto
386 °C. However, heating above 386 °C triggers an abrupt
weight loss (15%) and this can be attributed to the loss of
organic substituents present on the pristine phosphonate
framework. On the contrary, the nanocomposite did not show
any sharp weight loss on heating above 117 °C. Instead a
steady but slow weight loss, which continues even beyond
700 °C is observed. Thus, thermogravimetric analysis clearly
reveals the incorporation of Pd nanoparticles greatly enhances
the stability of the framework. The interaction of the dispersed
Pd nanoparticles with the phosphonate groups of the framework
can be possibly attributed to the augmentation of the thermal
stability of the composite.
Results and Discussion
2 2 6
Hydrothermal reaction of ZrOCl .8H O and H L in presence of
Powder X-ray diffraction patterns of MZrP and Pd@MZrP are
depicted in Figure 1. Several broad peaks are observed in
powder X-ray diffraction pattern of MZrP and this is
characteristic of mesoporous phosphonate frameworks. All the
peaks observed in the powder X–ray diffraction pattern of MZrP
are also observed in the powder X-ray diffraction pattern of
Pd@MZrP albeit with relatively poor intensity. Nevertheless, it
clearly establishes that the framework structure of the pristine
phosphonate network is intact in the composite Pd@MZrP.
Apart from all the peaks corresponding to the phosphonate
framework, an intense peak at 2θ = 39° is observed in the
powder X-ray diffraction pattern of Pd@MZrP and this can be
attributed to the diffraction from 111 plane of Pd(0) nanoparticles.
cetyltrimethyl ammonium bromide (CTAB) at 130 °C for 3 days
and subsequent removal of CTAB by treatment with acidified
ethanol produced
Zr (L) ].nH O (MZrP). Thereafter, impregnation of Pd(OAc)
onto the mesoporous framework MZrP followed by reduction led
to the isolation of a composite material, [Pd0.5Zr (L) ].nH
Pd@MZrP) where Pd particles are homogeneously dispersed
a mesoporous zirconium phosphonate,
[
3
2
2
2
3
2
2
O
(
over the framework (Scheme 1). Both the compounds were
characterized by using different spectroscopic, analytical and
microscopic techniques such as FT-IR, TGA, powder X-ray
diffraction, SEM, TEM, EDX, BET surface area analysis, XPS
and solid state NMR.
1
. CTAB
H2O3P
PO3H2
2
. Hydrothermal
1. Pd(OAc)2
. NaBH4
+
ZrOCl2.8H2O
[Zr3(L)2].nH2O
[Pd0.5Zr3(L)2].nH2O
2
2. HCl, C2H5OH
PO3H2
H6L)
(MZrP)
(Pd@MZrP)
(
Scheme 1. Synthesis of MZrP and Pd@MZrP.
The FT-IR spectrum of MZrP and Pd@MZrP depicted in Figure
S1. Apart from an intense signal observed at 1417 cm-1 in case
of Pd@MZrP, FT-IR spectra of both the compounds show peaks
in similar regions which essentially indicate no change in
structure of MZrP upon loading of Pd nanoparticles. Intense
absorptions at 1031 cm-1 and 1018 cm-1 in the FT-IR spectrum of
MZrP and Pd@MZrP, respectively, can be easily attributed to
P=O and Zr-O-P stretching vibrations. The aromatic C=C
stretching vibrations appear as medium intensity signals
Figure 1. Powder X-Ray Diffraction spectrum of MZrP (a) and Pd@MZrP (b).
SEM images of MZrP and Pd@MZrP depicted in Figure S4
reveal that the morphology of the pristine phosphonate
framework did not change substantially upon incorporation of
Pd(0) nanoparticles within the framework. EDX analysis
performed along with SEM also confirms the presence of all
elements as expected in the prinstine zirconium phosphonate
framework as well as in its palladium nanocomposite. TEM
images of the composite shows the homogeneous and abundant
distribution of Pd(0) particles of average size 7-8 nm over the
entire framework (Figure 2).
-1
-1
centered at 1629 cm and 1643 cm in the FT-IR spectrum of
MZrP and Pd@MZrP, respectively. Absence of any peak within
850-2930 cm-1 in both the FT-IR spectra confirms the complete
2
removal of CTAB used during the synthesis of the mesoporous
framework. Moreover, broad and intense signals observed near
-1
3
400 cm are attributed to O-H stretching vibration of co-
ordinated and lattice water molecules present in the frameworks.
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European Journal of Inorganic Chemistry
10.1002/ejic.201701313
FULL PAPER
Figure 3. XPS spectra of MZrP (a) and Pd@MZrP (b) at Zr (3d) region.
and 3p5/2 electrons of tetravalent zirconium present in the
framework (Figure 4). It is pertinent to note that peaks for
divalent palladium also appear in same region and in order to
unambiguously assign these peaks to Zr (3p), we carefully
compared the area under the peaks. It may be noted that the
area under the peak observed at 347.2 eV is considerably high
as compared to peaks observed at 335.2 eV and therefore it is
unlikely that they appear from 3d3/2 and 3d5/2 electrons of
divalent palladium. Similarly the area under the peak observed
at 340.4 eV is considerably small as compared to the area under
the peak observed at 333.1 eV to assign these peaks for 3d3/2
and 3d5/2 electrons of metallic palladium respectively. Thus, XPS
analysis confirms the presence of metallic palladium
nanoparticles within the nanocomposite, Pd@MZrP.
Figure 2. TEM images of Pd@MZrP.
The oxidation states of the elements present in MZrP and
Pd@MZrP are probed with X-ray photoelectron spectroscopic
(
XPS) analysis. The broad peak centered at 284.5 eV observed
in the C (1s) region of the XPS spectrum of both MZrP and
Pd@MZrP can be assigned to aromatic C=C and C-C bonds.
Further a broad signal observed at 285.9 eV can be assigned to
C-P bonds. Interestingly, the intensity of the peak observed at
285.9 eV diminishes considerably in the composite, Pd@MZrP
and a new broad peak centered at 288.7 eV is observed and it
can be attributed to the strong interaction of the Pd
nanoparticles with the framework (Figure S5).
XPS data of MZrP in 2p region of phosphorus show two
broad peaks centered at 134.3 eV and 133.4 eV and these can
be easily assigned to 2p1/2 and 2p3/2 electrons of pentavalent
phosphorus. Inclusion of Pd nanoparticles onto the phosphonate
framework significantly modify the electronic environment
around phosphorus as the peaks corresponding to 2p1/2 and
5+
2p3/2 electrons of P are observed at 133.8 eV and 132.7 eV
respectively in case of Pd@MZrP (Figure S6).
Figure 4. XPS spectra of Pd@MZrP at Pd (3d) region.
Additional evidence regarding the strong influence of the Pd
nanoparticles on the electronic environement of elements
present in the phosphonate framework is acquired from XPS
analysis of Zr (3d) region for both MZrP and Pd@MZrP. In case
of the pristine zirconium phosphonate framework, peaks
corresponding to 3d5/2 and 3d3/2 electrons of tetravalent
zirconium are observed at 183.2 eV and 185.6 eV respectively.
However, the characteristic peaks for Zr4+ (3d3/2) and (3d5/2) are
observed at 182.4 and 184.8 eV respectively in case of the
nanocomposite, Pd@MZrP (Figure 3).
The textural property of a substance is intimately related to
its ability for accommodating guest molecules and therefore BET
surface area analysis of the pristine zirconium phosphonate,
MZrP was investigated. N
of MZrP at 77K shows a type IV N
isotherm with hysteresis loop typical of mesoporous
frameworks (Figure 5). The sample was desorbed at 300 °C for
h. The BJH pore size distribution analysis based on the
2
adsorption and desorption isotherms
2
adsorption/desorption
a
3
XPS analysis of the nanocomposite Pd@MZrP was
performed in Pd (3d) region to ascertain the oxidation state of
palladium. Two distinct peaks observed at 335.2 and 340.4 eV
can be attributed to 3d3/2 and 3d5/2 electrons of metallic
palladium. Apart from that, two additional peaks observed in the
Pd(3d) region at 333.1 and 347.2 eV can be assigned to 3p3/2
desorption data reveal the major mean pore diameter as 3.7 nm
with two other minor pores of diameters 5.1 nm and 6.4 nm are
also prevalent within the mesoporous material. Surface area
analysis based on multipoint BET method establish that the
pristine zirconium phosphonate framework has a BET surface
2
area 269 m /g and thereby establish the viability of using the
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European Journal of Inorganic Chemistry
10.1002/ejic.201701313
FULL PAPER
present framework to accommodate metallic nanoparticles over
the surface. Micropore volume estimation was performed using
t-plot (Figure S7) and micropore surface area was found to be
was investigated (Scheme 2). Initial investigations focused on
screening the optimum amount of catalyst, reaction temperature
and base for satisfactory conversion. Although substantial
conversion was observed at room temperature itself, it was
finally established that treatment of reaction mixture at 80 °C in
ethanol in presence of 0.15 mol% of Pd catalyst gives the
highest yield of cross coupled product (Table 1).
2
2
211.8 m /g while the external surface area is 56.8 m /g.
Additionally, the BJH cumilative volume of pores between 2-100
3
nm diameter was found out to be 0.075 cm /g.
B(OH)2
Br
Ethanol, Base
Catalyst, 6 h
+
NO2
+
NO2
Scheme 2. Suzuki-Miyaura reaction at different conditions with Pd@MZrP as
catalyst.
Table 1. Yield at different temperatures to optimize the reaction temperature
2
Figure 5. (a) N adsorption/desorption isotherm of MZrP at 77 K (b) BJH pore
size distribution pattern of MZrP.
Sl.
No.
Temperature
(°C)
Catalyst Amount
(mol% of Pd
present)
Base
Yield (%)
The influence of Pd(0) nanoparticles on the chemical
environment of the constituent atoms in the phosphonate
framework was investigated by solid state 13C and 31P NMR
spectroscopy. C NMR spectrum of MZrP showed four well
resolved peaks and all of them can be easily assigned to carbon
atoms associated to the tris-phosphonate ligand. While peaks at
1
2
3
4
5
6
7
8
9
rt
0.10
0.10
0.10
0.10
0.07
0.15
0.20
0.10
0.10
0.10
0.10
0.10
K
2
CO
3
50
~0
79
88
81
92
92
15
64
55
82
35
rt
(Et)
3
N
1
3
50
80
80
80
80
80
80
80
80
80
K
K
K
K
K
2
2
2
CO
CO
CO
3
3
3
135.6 and 128.4 ppm can be attributed to two types of aromatic
carbon atoms present in the phosphonate ligand, distinct peaks
observed at 28.9 and 17.9 ppm correspond to the aliphatic
methylene and methyl carbon atoms respectively (Figure S8).
13C MAS NMR spectrum of the nanpcomposite, Pd@MZrP
reveal that the chemical environment of the methyl carbon atom
remain largely unaltered upon incorporation of Pd(0)
nanoparticles onto the framework as it resonates at 17.7 ppm.
However, the peak corresponding to methylene group is slightly
downfielded and resonates as a singlet at 30.1 ppm while the
two aromatic carbon atoms appear as a broad singlet centered
at 132.7 ppm.
2
CO
3
2
CO
3
(Et)
3
N
NaOH
10
11
12
Na
3
PO
4
Na
2
CO
3
Solid state 31P NMR spectroscopic analysis of MZrP and
Pd@MZrP unambiguously establish the strong interaction
NaHCO
3
between the Pd(0) nanoparticles and the zirconium phosphonate
framework in the nanocomposite. Solid state 31P NMR spectra of
The catalytic efficacy of Pd@MZrP in Suzuki-Miyaura cross
coupling reaction was further investigated by using different
phenyl boronic acids and aryl bromides as substrates under the
optimum reaction condition. The results of different Pd@MZrP
catalyzed cross coupling reactions are summarized in Table 2. It
is observed that the presence of electron withdrawing
substituent either on the boronic acid or aryl bromide
considerably decreased the yield of the cross-coupling product
and this is in agreement with the established reaction
mechanism of Suzuki-Miyaura cross coupling reaction.
The reusability of Pd@MZrP as a catalyst in Suzuki-
Miyaura cross coupling reaction was investigated by using
phenyl boronic acid and 4-bromobenzonitrile as substrates. The
nanocomposite can be easily recovered quantitatively from the
reaction mixture by centrifugation and subsequently decanting
the supernatant liquid. The solid catalyst recovered from the
reaction mixture was dried in an oven at 100 °C for 2 h to
both the compounds feature only one distinct peak and it reveals
the presence of only one type of phosphorus atom in both the
cases. Further, the chemical shift of the phosphorus atom
present in the pristine phosphonate framework is 12.8 ppm while
considerable deshielding is observed in case of the
nanocomposite as the 3 P NMR signal appears at 19.9 ppm
1
Figure S9). Thus, solid state 13C and 31P NMR spectroscopy
(
clearly suggest strong interaction between the phosphonate
framework and the Pd(0) nanoparticles within the
nanocomposite.
Pd@MZrP catalyzed Suzuki-Miyaura cross coupling
reaction
The catalytic efficacy of Pd@MZrP in Suzuki-Miyaura cross
coupling reaction between aryl boronic acids and aryl bromides
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European Journal of Inorganic Chemistry
10.1002/ejic.201701313
FULL PAPER
was further used as catalyst in Suzuki-Miyaura cross coupling
reaction. However, no detectable conversion of the substrates
were observed in all the cases. Thus, the intigrity of the
composite during catalytic reactions was further established by
leaching test which ruled out any obvious leaching of
immobilized Pd from the composite.
Table 2. Yield at different temperatures to optimize the reaction temperature
Br
B(OH)2
Ethanol, K2CO3
+
+
R1
Catalyst (0.15 mol% of Pd),
R1
6
h, Reflux
A
B
C
D
Conclusions
CH3
CN
NO2
N
1
C (22 %)
2C (94 %)
3C (80 %)
4C (92 %)
In summary, a robust mesoporous zirconium phosphonate
framework has been prepared by using surfactant assisted sol-
gel method and thereafter palldium nanoparticles are
immobilized over the mesoporous framework by impregnation
method coupled with subsequent reduction. Detailed analytical,
spectroscopic, microscopic and textural studies of the
nanocomposite material revealed that palladium nanoparticles of
average size 7-8 nm are dispersed homogeneously over the
entire zirconium phosphonate framework. Due to the robust
nature of the framework as well as strong interaction between
the phosphonate groups with the palladium nanoparticles
immobilized over the framework, the composite acts as a
reusable heterogeneous catalyst in Suzuki-Miyaura cross
coupling reaction with reasonably less decrease in efficiency
even after repeated use upto 5th times. The mesoporous
zirconium phosphonate framework offers a versatile platform to
immobilize various reactive metallic nanoparticles primarily due
to its robustness and also its ability to anchor different metallic
elements through the phosphonate groups. Thus, the present
work can be further extended to other metallic nanoparticles
which can then be exploited to carry out industrially relevant
organic transformations.
O
CN
OCH3
O
5
C (51 %)
6C (90 %)
7C (29 %)
8C (85 %)
H3CO
H3CO
CN
H3CO
NO2
O
9C (74 %)
10C (71 %)
11C (65 %)
remove any occluded solvent molecules and then weighed
before addition to the next batch of reactants. It was found that
Pd@MZrP is an efficient reusable catalyst as the reasonably
good yield of the cross-coupling product was obtained upto 5th
cycle. Observing a stable yield production, the reusability
experiments were not continued any further after 5th cycle
(
Figure 6).
Experimental Section
Materials and methods
All the chemicals were procured from commercial sources and used as
received without any further purification. Solvents were also purchased
from commercial sources and were distilled prior to use, adopting
common purification techniques. Mesityl-1,3,5-tris(methylenephosphonic
acid) was synthesized following a reported procedure.[39] Melting points
were recorded on a Buchi (M-560) melting point apparatus and reported
without any correction. Nicolet Impact I-410 and Perkin Elmer Frontier
MIR-FIR FT-IR spectrophotometers were used to obtain Fourier
Figure 6. Reusability study of catalyst Pd@MZrP for Suzuki coupling reaction.
transformed infrared spectra between 400-4000 cm . 1H and C NMR
spectra were recorded on a JEOL JNM-ECS400 NMR spectrometer
operating at 400 MHz and samples were dissolved in deuterated solvents.
-
1
13
FT-IR and powder X-ray diffraction analysis of the catalyst
recovered after five catalytic cycles was also recorded to
examine the structural integrity of Pd@MZrP. All the
characteristic peaks observed in FT-IR spectra of the fresh
composite are present in the material recovered after fifth
catalytic cycles (Figure S10). Similarly, powder X-ray diffraction
pattern of the catalyst after fifth cycle does not show any
significant difference with that of freshly synthesized catalyst.
Moreover, the specific peak obtained for Pd at 2θ=39° is
distinctly seen in the catalyst recovered after fifth cycle which
establish the integrity of the composite (Figure S11). The mother
liquor isolated on completion of catalytic reactions in each cycle
4
Chemical shifts are reported in parts per million downfield of Me Si (TMS)
as internal standard. Elemental analyses were performed on a Perkin
Elmer Model PR 2400 Series II Elemental Analyzer. ICP-OES analyses
were performed on Perkin Elmer Optima 2100DV analyzer.
Thermogravimetric analyses were performed on a Shimadzu TGA-50
thermal analyzer. The scanning electron microscopy (SEM) analyses
were carried out using a JEOL JSM-6390LV SEM, equipped with an
Energy-Dispersive X-ray analyzer. The powder X-ray diffraction patterns
were recorded on
a Bruker AXS D8 Focus X-ray diffractometer
instrument using a nickel-filtered CuKα (λ = 0.15418 nm) radiation source
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European Journal of Inorganic Chemistry
10.1002/ejic.201701313
FULL PAPER
and scintillation counter detector. Solid state 13C and 31P spectra were
recorded on a AVANCE III 500WB spectrometer using adamantane (38
after separation of the heterogeneous catalyst from the reaction mixture
by filtration. Toluene was used as Internal Standard and IRF value was
calculated as-
ppm) and
H PO
3 4
(0 ppm) as references, respectively. X-Ray
photoelectron spectroscopy (XPS) analysis was carried out on
a
KRATOS Axis Ultra DLD electron spectrometer using an Al Kα (1486.6
IRF = (Area IS× Amount SC)/(Amount IS × Area SC
)
eV) radiation source. GC-MS was recorded on a Perkin Elmer Clarus
6
00C Mass Spectrometer. The pore structures were measured by a FEI
Where, IS: Internal standard and SC: Substance of consideration.
TECNAI G2 20 S-TWIN transmission electron microscope operated at an
accelerating voltage of 200 kV. Nitrogen adsorption/desorption isotherms
were obtained by a ASAP 2020 surface area analyzer (Micromeritics).
Acknowledgements
Synthesis of MZrP
Generous financial supports from SERB-DST (Grant No.
EMR/2016/002178) and CSIR, New Delhi (Grant No.
Cetyltrimethylammonium bromide (0.18 g, 0.5 mmol) was dissolved in 5
mL
water
and
stirred
for
2
h.
Then
mesityl-1,3,5-
01(2789)/14/EMR-II) and are gratefully acknowledged. Authors
tris(methylenephosphonic acid) (0.20 g, 0.5 mmol) in 3 mL water was
added to the CTAB solution and the resulting solution was stirred for 12 h.
ZrOCl ∙8H O (0.16 g, 0.5 mmol) dissolved in 4 mL water was then added
2 2
are thankful to C. Lorentz (IRCELYON) for solid-state NMR
studies. Suchibrata Borah thanks CSIR for SRF fellowship grant.
to the above solution under continuous stirring. Soon after the addition of
zirconium oxychloride, formation of a cream coloured precipitate was
observed. The whole mixture was stirred for another 12 h and finally
transferred to a teflon lined stainless steel autoclave, sealed and placed
in an electric oven at 403 K for 3 days. After cooling to room temperature,
the white product formed was filtered and washed several times with
distilled water. To remove the surfactant, the as-synthesized material
was heated with 20 mL of acidified ethanol at 333 K and then washed
with pure ethanol to remove the remaining acid. The extracted material
was dried in vacuum. Yield 0.26 g; Elemental analysis calculated for
Keywords: mesoporous framework • zirconium • palladium •
catalysis • reusability
References
[1]
[2]
K. An, G. A. Somorjai, ChemCatChem 2012, 4, 1512-1524.
G. A. Somorjai, J. Y. Park, Angew. Chem., Int. Ed. 2008, 47, 9212-
9228.
24 50 28 6 3
C H O P Zr : C 23.1, H 4.0, P 14.9, Zr 21.9 Found: C 23.5, H 3.9, P
-
1
1
7
5.0 Zr 21.7. FT-IR (KBr, cm ): 3400 (br), 1629 (m), 1456 (w), 1031 (s),
[3]
C. Chen, Y. Kang, Z. Huo, Z. Zhu, W. Huang, H. L. Xin, J. D. Snyder, D.
Li, J. A. Herron, M. Mavrikakis, M. Chi, K. L. More, Y. Li, N. M.
Markovic, G. A. Somorjai, P. Yang, V. R. Stamenkovic, Science 2014,
343, 1339-1343.
46 (w), 506 (m); 13C NMR (δ ppm): 135.6, 128.4, 28.9, 17.9; 31P NMR (δ
ppm): 12.8; XPS (eV): 284.5, 285.9 (C 1s); 134.3, 133.4 (P 2p); 183.2,
85.6 (Zr 3d).
1
[
4]
R. V. Jagadeesh, A. E. Surkus, H. Junge, M. M. Pohl, J. Radnik, J.
Rabeah, H. Huan, V. Schunemann, A. Bruckner, M. Beller, Science
Synthesis of Pd@MZrP
2
013, 342, 1073-1076.
X. W. Xie, Y. Li, Z. Q. Liu, M. Haruta, W. J. Shen, Nature 2009, 458,
46-749.
S. Cao, F. Tao, Y. Tang, Y. Li, J. Yu, Chem. Soc. Rev. 2016, 45, 4747-
765 and references therein.
A. Balanta, C. Godard, C. Claver, Chem. Soc. Rev. 2011, 40, 4973-
985.
[
[
[
5]
6]
7]
Pd(OAc) (0.07 g, 0.34 mmol) was dissolved in 10 mL THF and 0.27 g of
2
7
compound MZrP was added. The mixture was stirred overnight at room
temperature, filtered and the residue was washed several times with THF
and the remaining solid was dried under vacuum. Subsequently 0.15 g of
4
4
the solid was added to 0.04 g of NaBH (1.07 mmol) solution in ethanol
4
at 0 °C and the resulting mixture was stirred for 2 h at room temperature.
Later, it was centrifuged, washed with ethanol several times and also
with diethylether and finally air dried. Yield 0.16 g; Elemental analysis
[
[
8]
9]
T. Vats, S. Dutt, R. Kumar, P. F. Siril, Scientific Reports 2016, 6, 33053.
M. Zheng, P. Li, G. Fu, Y. Chen, Y. Zhou, Y. Tang, T. Lu, Appl. Catal.,
B 2013, 129, 394-402.
54 30 6 3
calculated for C24H O P Zr Pd0.5: C 21.5, H 4.1, P 13.9, Zr 20.5 Pd 3.9
[
[
10]
11]
X. Chen, G. Wu, J. Chen, X. Chen, Z. Xie, X. Wang, J. Am. Chem. Soc.
-
1
Found: C 21.2, H 4.2, P 13.8 Zr 20.1, Pd 3.9; FT-IR (KBr, cm ): 3431 (br),
2011, 133, 3693-3695.
1
3
1
3
643 (m), 1417 (s), 1018 (s), 738 (w), 526 (w); 13C NMR (δ ppm): 132.7,
0.1, 17.7; 31P NMR (δ ppm): 19.9; XPS (eV): 284.5, 285.9, 288.7 (C 1s);
33.8, 132.7 (P 2p); 182.4, 184.8 (Zr 3d); 333.1, 335.2, 340.4, 347.2 (Pd
d).
F. Wang, J. Mielby, F. H. Richter, G. Wang, G. Prieto, T. Kasama, C.
Weidenthaler, H.-J. Bongard, S. Kegnæs, A. Forstner, F. Schuth,
Angew. Chem., Int. Ed. 2014, 53, 8645-8648.
[
[
[
12]
13]
14]
Y. Yu, T. Hu, X. Chen, K. Xu, J. Zhanga, J. Huang, Chem. Commun.
2
011, 47, 3592-3594.
S. Lin, X. Ye, R. S. Johnson, H. Guo, J. Phys. Chem. C 2013, 117,
7319-17326.
Typical procedure for Suzuki-Miyaura reaction catalyzed by
Pd@MZrP
1
J. Zhao, M. Shao, D. Yan, S. Zhang, Z. Lu, Z. Li, X. Cao, B. Wang, M.
Wei, D. G. Evans, X. Duan, J. Mater. Chem. A 2013, 1, 5840-5846.
A. Dhakshinamoorthy, H. Garcia, Chem. Soc. Rev. 2012, 41, 5262-
5284.
Aryl boronic acid (0.24 mmol) was dissolved in 6 mL ethanol to which
aromatic bromo derivative (0.2 mmol), K
2
CO
3
(0.2 mmol) and catalyst
[15]
[16]
[17]
[18]
Pd@MZrP (0.15 % of Pd) were added. The mixture was refluxed and
progress of the reaction was monitored by using TLC. After the reaction
was complete, the reaction mixture was filtered and GC-MS of the same
was recorded for yield calculation using toluene as the internal standard.
The cross coupling products were isolated by column chromatography
with 5% ethyl acetate/hexane mixture as eluent and characterized by 1H
NMR and 13C NMR. Yield of all reactions were calculated using GC-MS
D. J. Tranchemontagne, J. L. Mendoza-Cortés, M. O’Keeffe, O. M.
Yaghi, Chem. Soc. Rev. 2009, 38, 1257-1283.
P. Küsgens, M. Rose, I. Senkovska, H. Fröde, A. Henschel, S. Siegle,
S. Kaskel, Microporous Mesoporous Mater. 2009, 120, 325-330.
P. M. Schoenecker, C. G. Carson, H. Jasuja, C. J. Flemming, K. S.
Walton, Ind. Eng. Chem. Res. 2012, 51, 6513-6519.
This article is protected by copyright. All rights reserved.

European Journal of Inorganic Chemistry
10.1002/ejic.201701313
FULL PAPER
[
[
[
[
19]
20]
21]
22]
J. B. Decoste, G. W. Peterson, B. J. Schindler, K. L. Killops, M. A.
Browe, J. J. Mahle, J. Mater. Chem. A 2013, 1, 11922-11932.
K. Tan, N. Nijem, P. Canepa, Q. Gong, J. Li, T. Thonhauser, Y. J.
Chabal, Chem. Mater. 2012, 24, 3153-3167.
K. Tan, N. Nijem, Y. Gao, S. Zuluaga, J. Li, T. Thonhauser, Y. J.
Chabal, CrystEngComm 2015, 17, 247-260.
C. Y. Yang, A. Clearfield, React. Polym., Ion Exch., Sorbents 1987, 5,
13-21.
[
[
23]
24]
Y. Wan, D. Zhao, Chem. Rev. 2007, 107, 2821-2860.
T. Z. Ren, X. H. Zhu, T. Y. Ma, Z. Y. Yuan, Adsorpt. Sci. Technol. 2013,
31, 535-548.
[
[
[
[
[
[
[
25]
26]
27]
28]
29]
30]
31]
X. J. Zhang, T. Y. Ma, Z. Y. Yuan, Chem. Lett. 2008, 37, 746-747.
T. Kimura, Chem. Mater. 2005, 17, 5521-5528.
T. Kimura, Chem. Mater. 2003, 15, 3742-3744.
T. Kimura, Chem. Mater. 2005, 17, 337-344.
T. Y. Ma, X. Z. Lin, Z. Y. Yuan, Chem. Eur. J. 2010, 16, 8487-8494.
Y. P. Zhu, T. Z. Ren, Z. Y. Yuan, New J. Chem. 2014, 38, 1905-1922.
Y. P. Zhu, T. Y. Ma, Y. L. Liu, T. Z. Ren, Z. Y. Yuan, Inorg. Chem.
Front. 2014, 1, 360-383.
[
[
32]
33]
T. Y. Ma, Z. Y. Yuan, ChemSusChem 2011, 4, 1407-1419.
M. Pramanik, M. Nandi, H. Uyama, A. Bhaumik, Catal. Sci. Tech. 2012,
2, 613-620.
[
34]
A. Dutta, M. Pramanik, A. K. Patra, M. Nandi, H. Uyama, A. Bhaumik,
Chem. Commun. 2012, 48, (53): 6738-6740.
[
[
35]
36]
X. Z. Lin, Z. Y. Yuan, Eur. J. Inorg. Chem. 2012, 2661-2664.
H. P. Perry, J. Law, J. Zon, A. Clearfield Microporous Mesoporous
Mater. 2012, 149, 172-180.
[
37]
F. Costantino, R. Vivani, M. Bastianini, L. Ortolani, O. Piermatti, M.
Nocchetti, L. Vaccaro, Chem. Commun. 2015, 51, 15990-15993.
Y. Ma, X. Ma, Q. Wang, J. Zhou, Catal. Sci. Tech. 2012, 2, 1879-1885.
R. Murugavel, M. P. Singh, New J. Chem. 2010, 34, 1846-1854.
.
[
[
38]
39]
This article is protected by copyright. All rights reserved.

European Journal of Inorganic Chemistry
10.1002/ejic.201701313
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FULL PAPER
Key Topic*
Suchibrata Borah, Shashank Mishra
Luis Cardenas and Nayanmoni Gogoi*
Page No. 1-8.
Title
A robust mesoporous Zr(IV) organophosphonate framework is prepared by
surfactant assisted sol-gel method and it is used as a versatile scaffold to host Pd
nanoparticles of average size 7-8 nm. The Pd nanoparticle impregnated composite
acted as a robust, efficient and reusable catalyst in Suzuki-Miyaura cross coupling
reaction of aryl bromides with aryl boronic acids.
Pd nanoparticles dispersed on Zr(IV)
organophosphonate:
A robust and
reusable catalyst for Suzuki-Miyaura
cross-coupling reaction
*Pd catalyst, Suzuki-Miyaura cross coupling reaction, Zr organophosphonate
This article is protected by copyright. All rights reserved.