Catalysis of C-C cross-coupling reactions in aqueous solvent by bis- and tris(ferrocenyltriazolylmethyl)arene-β-cyclodextrin-stabilized Pd 0 nanoparticles

Article abstract of DOI:10.1002/ejic.201200098

Mono-, bis-, and tris(4-ferrocenyl-1,2,3-triazolylmethyl)arene-β- cyclodextrin adducts have been used to prepare new Pd⁰ nanoparticle (PdNP) catalysts for C-C cross-coupling reactions in EtOH/H₂O. The results show that these catalysts work well in Miyaura-Suzuki and Heck reactions with iodoarenes at 25 and 80 °C, respectively, with turnover numbers (TONs) of up to 31000 for standard Miyaura-Suzuki reactions of PhI when 10 ppm of the Pd catalyst (5 nm PdNPs) were used. The results show the benefit for PdNP catalysis of encapsulating hydrophobic catalytic systems between peripheral water-solubilizing cyclodextrins as bolamphiphile-like materials because the open monoferrocenyltriazolylmethylbenzene system shows a considerably reduced catalytic efficiency compared with bis- and tris(4-ferrocenyl-1,2,3- triazolylmethyl)arene-β-cyclodextrin adducts. Copyright

Full text of DOI:10.1002/ejic.201200098

Job/Unit: I20098
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FULL PAPER
DOI: 10.1002/ejic.201200098
Catalysis of C–C Cross-Coupling Reactions in Aqueous Solvent by Bis- and
Tris(ferrocenyltriazolylmethyl)arene–β-Cyclodextrin-Stabilized Pd0
Nanoparticles
Liyuan Liang,[a] Abdou K. Diallo,[a] Lionel Salmon,[b] Jaime Ruiz,[a] and Didier Astruc*[a]
Keywords: Cyclodextrins / Nanoparticles / Palladium / Heterogeneous catalysis / C–C coupling / Click chemistry /
Sandwich complexes
Mono-, bis-, and tris(4-ferrocenyl-1,2,3-triazolylmethyl)ar-
ene–β-cyclodextrin adducts have been used to prepare new
Pd0 nanoparticle (PdNP) catalysts for C–C cross-coupling re- ripheral water-solubilizing cyclodextrins as bolamphiphile-
were used. The results show the benefit for PdNP catalysis
of encapsulating hydrophobic catalytic systems between pe-
actions in EtOH/H2O. The results show that these catalysts
work well in Miyaura–Suzuki and Heck reactions with
iodoarenes at 25 and 80 °C, respectively, with turnover num-
like materials because the open monoferrocenyltriazolylme-
thylbenzene system shows a considerably reduced catalytic
efficiency compared with bis- and tris(4-ferrocenyl-1,2,3-tri-
bers (TONs) of up to 31000 for standard Miyaura–Suzuki re- azolylmethyl)arene–β-cyclodextrin adducts.
actions of PhI when 10 ppm of the Pd catalyst (5 nm PdNPs)
hydrophobic organic and organometallic substrates in their
Introduction
hydrophobic interior cavity. The hydrophilic hydroxy
groups at the surface of cyclodextrins have often been
modified by functional groups such as thiolates,[9] sulfo-
butyl ether,[16a] cholesterol,[16c] hydroxypropyl,[17a] alkyl,
and poly(ethylene oxide) chains.[18] These functionalities
have been used to stabilize catalytically active nanopar-
ticles[13] as well as for applications in self-assembly[19a] and
drug delivery.[19b] The hydrophobic interior cavity of CDs
permits their use as hosts to accommodate a wide range of
organic or lipophilic guest molecules.[16] The main driving
forces of the host–guest inclusion complexes are indeed
hydrophobic and van der Waals interactions, the release of
CD ring strain, changes in solvent surface tensions, and hy-
drogen bonding with CD hydroxy groups.[20]
The inclusion of ferrocene by β-cyclodextrin was first de-
scribed in 1975.[21] The stability of ferrocene and the ferro-
cenyl (Fc) group in aqueous and aerobic media, the accessi-
bility of a large variety of derivatives, the lack of toxicity,
and favorable redox recognition[22] and electrochemical
properties[23] have made ferrocene and its derivatives very
popular molecules for biological applications as sensors and
drugs involving conjugation with biomolecules. Ferrocene
and Fc derivatives are well known to be good guests for β-
CD, forming relatively stable 1:1 complexes in water by the
penetration of Fc into the internal hydrophobic cavity of
the β-CD host.[9,24] Therefore stable and hydrophilic β-CD–
Fc host–guest assemblies have been used to prepare and
stabilize metal NPs for catalysis in aqueous solvents.[18]
Kaifer and co-workers showed that the catalytic activity of
Palladium is the most frequently used transition metal
in catalysis,[1] especially for C–C cross-coupling reactions,[2]
among which the Heck[3] and Miyaura–Suzuki[4] reactions
are possibly the most useful. Metal nanoparticles (NPs)
have appeared as a very promising approach to efficient ca-
talysis under mild, environmentally benign conditions be-
cause of their large surface-to-volume ratio.[5] PdNPs[6] sta-
bilized by polymers,[7] dendrimers,[8] or cyclodextrins
(CDs)[9] have largely been used to catalyze C–C cross-cou-
pling reactions in water, in particular the Miyaura–Su-
zuki,[10a,10b] Sonogashira,[10] and Heck reactions.[10a,10b]
A
recent review has summarized the applications of PdNPs as
catalytic precursors in organic synthesis.[11]
Cyclodextrins,[12] a series of natural cyclic oligosac-
charides composed of several d-glucopyranose residues
joined by α-1,4 linkages, have commonly been used as sup-
ramolecular tools[13,14] in the synthesis and stabilization of
transition-metal NPs for homogeneous,[10c,10d] hetero-
geneous,[14] or biphasic[15] catalysis. Indeed, cyclodextrins
are a class of derivatives of choice in green chemistry[13] as a
result of their hydrophilicity and their ability to encapsulate
[a] Institut des Sciences Moléculaires, UMR CNRS N° 5255,
Université Bordeaux 1,
33405 Talence Cedex, France
E-mail: d.astruc@ism.u-bordeaux1.fr
[b] Laboratoire de Chimie de Coordination, UPR CNRS N° 8241,
31077 Toulouse Cedex 04, France
Supporting information for this article is available on the
WWW under http://dx.doi.org/10.1002/ejic.201200098.
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β-CD-modified PdNPs could be tuned through host–guest cenyl groups and β-CD. These compounds are soluble in
binding interactions.[9] These authors used β-CD-capped water, unlike the starting (ferrocenyl-1,2,3-triazolylmethyl)-
PdNPs for the catalysis of the Miyaura–Suzuki reaction.[25] arene derivatives.
Xue et al. prepared β-CD-capped PdNPs to catalyze Sono-
gashira reactions.[10c,10d] Senra and co-workers used hy-
droxypropyl α-CD-capped PdNPs for efficient C–C cou-
pling in water.[17] Monflier and co-workers have chemically
modified CDs to generate carbon-supported RuNPs for ap-
plication in gas-phase hydrogenation.[26]
Our research group has stabilized PdNPs,[27] PtNPs,[28]
and AuNPs[29] by the coordination of PdII, PtII, and AuIII
with the 1,2,3-triazolyl heterocyclic ligands of “click” den-
drimers[27–29] and polymers[30] followed by reduction to the
metal(0) species. In the case of PdNPs, this procedure has
been applied to the catalysis of olefin hydrogenation and
Miyaura–Suzuki reactions.[27,28,30] When these nanomateri-
als were functionalized by sulfonate groups, the reactions
could also be performed in aqueous media containing eth-
anol.[30] We are now examining more simple, rather small
“clicked” molecules containing ferrocenyl-1,2,3-triazolyl
groups. The idea was two-fold: 1) To use the triazolyl
groups as ligands again for PdII, which would also involve
a weak stabilization of the PdNPs formed by the reduction
of PdII, and 2 ) to use the ferrocenyl groups to form host–
guest complexes with β-CD that would solubilize the cata-
lytic materials in an aqueous medium.
The shapes of the molecular materials with two or three
ferrocenyl termini were designed with a view to form bol-
amphiphile-like[31] materials upon terminal β-CD encapsul-
Scheme 1. Synthesis of 4-methoxy-1-(4-ferrocenyl-1,2,3-triazolyl-
ation. The syntheses of these materials and their catalytic
methyl)benzene–β-cyclodextrin (a).
activities in Miyaura–Suzuki and Heck reactions in EtOH/
H2O (1:1) are described herein.
Result and Discussion
Preparation of the Ferrocenyl-1,2,3-triazolylmethyl–β-
Cyclodextrin Derivatives
We synthesized three (ferrocenyl-1,2,3-triazolylmethyl)ar-
ene derivatives by the reactions of mono-, 1,4-bis-, and
1,3,5-tris(azidomethyl)benzene derivatives and ethynylferro-
cene according to the copper-catalyzed alkyne azide
(CuAAC) “click” reaction.[32] Then, each of these com-
pounds was dissolved together with a slight excess of β-
cyclodextrin per ferrocenyl group (β-CD/Fc = 1.1) in DMF
and the orange mixtures were stirred at room temperature
for 24 h to ensure encapsulation of the peripheral ferrocenyl
groups by β-cyclodextrins.[25] After removing the DMF sol-
vent from this orange solution, pale-yellow powders of
(ferrocenyl-1,2,3-triazolylmethyl)arene–β-CD
derivatives
were obtained (Schemes 1–3). The excess β-CD was re-
moved by washing with dichloromethane (DCM). The 1:1
ferrocenyltriazole/β-CD stoichiometry was proven by inte-
gration of the corresponding 1H NMR signals (see the Sup-
Scheme 2. Synthesis of p-bis(4-ferrocenyl-1,2,3-triazolylmethyl)-
porting Information) to contain equal amounts of ferro- benzene–β-cyclodextrin (b).
2
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Catalysis of C–C Cross-Coupling Reactions
to reuse the catalyst was to reload the initial medium with
substrates, which leads to a slight decrease in catalytic ac-
tivity (see below). Although this is a drawback, these cata-
lysts are efficient when used fresh (or reloaded) in extremely
small amounts (see below).
Catalysis of the C–C Cross-Coupling Reactions
Miyaura–Suzuki Reactions
Comparison of Various Reactants
Two iodoarenes (iodobenzene and 4-iodoanisole) and
bromobenzene were used in Miyaura–Suzuki reactions with
four boronic acids (see Table 1 and Table 2). The catalytic
reaction of iodobenzene worked much better than with bro-
mobenzene, as expected. Comparison of various haloarenes
revealed that the catalytic reaction was less efficient when
the arene was substituted by electron-donating groups, such
as methoxy. This is expected because classically the oxidat-
ive addition step from PdII is slowed in the presence of such
a substituent. Thus, in the reactions of iodobenzene with
various boronic acids, the Miyaura–Suzuki reaction worked
well even with a very small quantity of Pd (0.001 mol-%,
i.e., 10 ppm), but in the case of 4-iodoanisole, a higher load
of catalyst was needed to obtain a quantitative yield. In the
case of bromobenzene, the yield was 54% at 25 °C after
72 h (Table 1, entry 14).
Influence of the Amount of Solvent on the Catalytic
Efficiency
Intriguingly, the amount of solvent in the system played
an important role in the catalysis. When 1 mol-% of Pd per
haloarene was used with c(Pd) = 2.8ϫ10–4 mol/L, the yield
of the Miyaura–Suzuki reaction was 76%. When the system
was diluted to c(Pd) = 1.4ϫ10–4 mol/L, 99% of the product
Scheme 3. Synthesis of 1,3,5-tris(4-ferrocenyl-1,2,3-triazolylmeth-
yl)benzene–β-cyclodextrin (c).
was obtained (Table 2, entry 1). With c(Pd)
=
1.4ϫ10–4 mol/L and 0.1 mol-% of Pd/haloarene, the yield
was 99.5%. In the case of 0.01 mol-% Pd/haloarene (reac-
tion carried out for 48 h at room temp.), if c(Pd) =
1.4ϫ10–5 mol/L, the yield was 10%, but with c(Pd) =
2.8ϫ10–5 mol/L, the yield was 98.4% (Table 2, entry 3). In
Preparation and Characterization of the New Supported
PdNP Catalysts
The supported PdNP materials were prepared in water the case of 0.001% Pd/haloarene (reaction carried out for
at room temperature under nitrogen by adding the brown- 72 h at room temp.), c(Pd) = 0.93ϫ10–5, 0.7ϫ10–5, or
orange aqueous solution of K2[PdCl4] (1 mg/mL) dropwise 0.28ϫ10–5mol/L, the yields were 2.7, 19.4, or 3.4%, respec-
to an aqueous solution of β-CD-encapsulated ferrocenylar- tively (Table 2, entry 4). Thus, it appears that the yields in-
ene derivative followed by reduction using NaBH4 under crease upon dilution to a rather large extent.
vigorous stirring. The orange solution turned black, which
Study of the Air Sensitivity and Catalysis in Water without
Co-Solvent
indicated the formation of PdNPs (Scheme 4). These freshly
prepared PdNP materials were used for the catalysis of C–
C coupling reactions. Characterization by TEM (see the
To examine the air sensitivity of the triazolylferrocenyl–
Supporting Information, pp. S8–S9) revealed the formation CD-stabilized Pd catalyst, the reaction (Table 1, entry 2)
of small PdNPs of the order of 5–6 nm in addition to large was also performed in air under the same conditions for
aggregates. The PdNPs also slowly decomposed to Pd comparison; the yield was 91.4%, which is a little lower
black, which is not catalytically active at room temp. The than that under nitrogen (99%). This means that the cata-
observation of aggregates by TEM is thus presumably an lytic system is not very sensitive to air during the Miyaura–
intermediate stage in the formation of Pd black. Thus, the Suzuki reactions. The same reaction was chosen to carry
catalyst could not be recycled after workup. The only way out the reaction in pure water and the yield was 8%, much
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Scheme 4. Preparation of PdNP materials with a, b, and c. The positioning and numbers of the PdNPs shown in the scheme are arbitrary.
Table 1. Results of the Miyaura–Suzuki reactions catalyzed by the PdNP catalyst supported by the bis-triazolylferrocenyl–CD (b).
[a] In the case of iodoarene substrates, the mol ratio was niodoarene/nboronic acid/n
= 1:1.5:2. In the case of bromoarene substrates, the
K3PO4
mol ratio was nbromoarene/nboronic acid/n
= 1:3:6. The reaction was carried out in EtOH/H2O (1:1). [b] Mol ratio of Pd per haloarene.
K3PO4
[c] GC yield.
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Catalysis of C–C Cross-Coupling Reactions
Table 2. Results of the Miyaura–Suzuki reactions catalyzed by the PdNP catalyst supported by the tris-ferrocenyl–CD material (c).
[a] In the case of iodoarene substrates, the mol ratio was niodoarene/nboronic acid/n
= 1:1.5:2. In the case of bromoarene substrates, the
K3PO4
mol ratio was nbromoarene/nboronic acid/n
= 1:3:6. The reaction was carried out in EtOH/H2O (1:1). [b ] Mol ratio of Pd per haloarene.
K3PO4
[c] GC yield. [d ] The result obtained with a mol ratio of Pd/CD = 2. All the other results were obtained with a mol ratio of Pd/CD =
1.
lower than in EtOH/H2O (1:1); with the solvent ratio from 99% for the first run to 88% for the second run, and
EtOH/H2O (1:4), the yield was 73%. The reactants are solu- to 79% for the third run. Thus, after two recycles, the PdNP
ble in EtOH and the homogeneous catalysis could be car- catalyst is somewhat less active.
ried out much more easily in EtOH/H2O than when the
Study of the Molar Relationship Between the
Triazolylferrocenyl–β-CD Complex and Palladium
reactants are not soluble (H2O only). In conclusion, the
best conditions for the catalysis are in EtOH/H2O (1:1) at
The PdNP catalysts were always prepared with a stoi-
chiometric (1:1) amount of triazolylferrocenyl–CD per Pd
atom before the catalysis. When the mol ratio of Pd/CD was
increased to two (by decreasing the amount of CD), how-
room temp. under N2.
Study of the Role of Triazolylferrocenyl–Cyclodextrin
Complexes in the Catalytic Efficiency
To determine whether the (ferrocenyl-1,2,3-triazolyl- ever, some interesting results were obtained. The reaction
methyl)arene–β-cyclodextrin plays a role in the efficiency of in Table 2, entry 12, is an example in which 2 mol-% Pd/
the palladium catalysis, an aqueous solution containing bromobenzene was used for catalysis. With the mol ratio
only K2[PdCl4] was treated directly with NaBH4 and the nPd/nCD = 2, the yield was 100%, much higher than that
classic reaction of Table 1, entry 1, was carried out under obtained with nPd/nCD = 1 (yield 27%). This result is the
nitrogen in EtOH/H2O (1:1) at room temp. for 24 h. A 13% reverse of that noted as an unpublished result by Senra and
yield of product was obtained, much lower than that ob- co-workers.[17] When the mol ratio nCD/nPd = 2 was used
tained with the triazolylferrocenyl–cyclodextrin complex for the same reaction, the product was obtained in a yield
(98%; Table 1, entry 1). Thus, the triazolylferrocenyl–cyclo- of 18%.
dextrin complex plays an important role in stabilizing
Comparison of the Catalytic Efficiency of the Mono-, Bis-,
and Tris(ferrocenyl-1,2,3-triazolylmethyl)benzene–β-
Cyclodextrins a, b and c
PdNPs in the catalysis. It is probable that, as usual,[7] the
heteroatoms (in this case, those of the triazolyl groups of
the support) play the role of weak supramolecular stabiliz-
On the basis of the catalytic results presented in Tables 1
and 2 there is no significant difference between b and c, but
a is not as effective as the two other supports. When the
PdNP catalyst for the Miyaura–Suzuki reaction (entries 1
and 9 of Table 2 are taken as examples) was prepared with
a, the yields were 54 and 68%, respectively, which is much
ers of the PdNP material. Note that the possibility of stabi-
lization of PdNPs by π interaction between the ligand and
the metallic (PdNP) surface has been suggested.[33]
Study of the Activity of the Catalyst upon Recharging the
Substrates
To study the activity of the PdNP catalyst, the reaction lower than in the presence of b (98 and 100%, respectively)
in Table 2, entry 1 was taken as an example. After each and c (99 and 95%, respectively). How does the ferrocenyl–
24 h, the Schlenk flask was recharged with reactants (this β-CD support stabilize the PdNP catalyst? In the cases of
procedure was carried out twice) and the yield was reduced b and c, there are two and three branches, respectively, that
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Table 3. Heck reactions catalyzed by PdNPs stabilized by b.
[a] 1% of Pd per haloarene; molar ratio: nhaloarene/nstyrene/n
= 1:3:6. [b] GC yield. [c] Result obtained for a Pd/CD molar ratio of 2.
K2CO3
Table 4. Heck reactions catalyzed by PdNPs stabilized by c.
[a] 1% of Pd per haloarene; molar ratio: nhalogeno–arene/nstyrene/n
= 1:3:6. [b] GC yield.
K2CO3
can encapsulate the PdNP catalyst and reactants, whereas the amount of Pd catalyst; the yield increases when the cat-
a has only one β-CD end (Scheme 4). This indicates that alyst concentration decreases. This negative influence of the
the catalytic reaction takes place between the β-CD termini precatalyst concentration again argues in favor of this “ho-
and the support framework.
meopathic mechanism”. A mechanism for the Heck cataly-
sis at high temperature for such a catalytically active Pd
catalyst in very small amounts was proposed by de Vries in
which atoms leached by a large PdNP precatalyst are
caught by the mother PdNP all the more efficiently as the
PdNP concentration increases.[2d,36] We have already en-
countered this situation in dendrimer-stabilized or -encap-
sulated PdNPs. It is of interest here to note that the triazolyl
of the PdNPs is stabilized even with wheel-shaped (pre-den-
dritic) ferrocenyltriazolyl materials such as c and in the bol-
amphiphile-type[31] compound b. The limit has been dis-
closed here in reducing the scale and branching level of the
support, as we note that the catalytic results obtained when
only one ferrocenyltriazolyl group is present in the support-
ing structure a are far from being as good as with b and c.
Heck Reaction
The Heck reactions between styrene and haloarenes were
also catalyzed by 1% PdNP stabilized by b and c; the results
are shown in Table 3 and Table 4. The results were obtained
with Pd/CD molar ratios of 2 and 1, respectively. In the
case of b, the yield was much more sensitive to the Pd/CD
ratio than in the case of c, for example, in the reaction in
Table 3, entry 1, the yield was 0% with a molar ratio of Pd/
CD of 1. This dramatic difference in yield might possibly
be caused by the fact that the ferrocenyl encapsulation by
β-CD could be somewhat reversible at 80 °C and that the
free β-CD in turn would then encapsulate the Pd catalyst,
leading to inhibition.
The dramatic difference in the influence of the Pd/CD
ratio on the catalytic efficiency between the Miyaura–Su-
zuki and Heck reactions is presumably due to the large dif-
ferences in reaction temperatures and mechanisms.
Conclusions
Three
(ferrocenyl-1,2,3-triazolylmethyl)arene–β-cyclo-
dextrin derivatives served as simple supports for the prepa-
ration and stabilization of PdNPs. These supported PdNPs
catalyze the Miyaura–Suzuki and Heck C–C cross-coupling
reactions of iodoarenes, but the bis- and tris-cyclodextrin
Mechanistic Discussion
The finding of the dramatic increase in yield in the Heck systems produce much better pre-catalysts than when only
reactions upon decreasing the amount of β-CD parallels one ferrocenyltriazolyl–β-CD branch is present in the sup-
that disclosed above for the Miyaura–Suzuki reaction. It is port material. This very important difference shows the effi-
remarkable because it signifies that CD inhibits the cataly- ciency of encapsulation of a hydrophobic catalytic system
sis. Because the major function of β-CD is the encapsul- with two or three peripheral water-solubilizing cyclodextrin
ation of a rather small species, this catalyst inhibition could caps, whereas the open system a does not work as well.
mean that the active Pd catalyst is such a small species, that Although the best catalysts (b and c) are extremely active
is, a Pd atom or a small cluster of two or three (or very with very high TONs at 25 °C with iodoarenes, the other
few) ligand-free atoms. This is in line with “homeopathic haloarenes are much more difficult or impossible to acti-
catalysis”, a term first used by Beletskaya and Cheprakov vate, as is usual with PdNPs under mild conditions.
for Heck reactions catalyzed by a minute amount of Pd
These very efficient catalysts can be reloaded with sub-
catalyst.[34–36] We also noted in the study the influence of strates, resulting in a slight, progressive decrease in yield.
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Catalysis of C–C Cross-Coupling Reactions
CD (a) was isolated and washed with DCM (5ϫ20 mL) to yield
0.140 g (87 % yield)of the product. 1H NMR ([D6]DMSO,
300 MHz): δ = 8.17 (s, 1 H, CH of triazole),7.31, 7.0 (d, 4 H, CH
of Ar), 5.75, 5.73, 5.69 (d, 14 H, CH of CD), 5.52 (s, 2 H, Ar-
CH2), 4.84, 4.46 (d and t, 14 H, CH of CD), 4.72, 4.30, 4.03 (t, 9
H, CH of Cp), 3.75, 3.34 (m, CH of CD) ppm. 13C NMR ([D6]-
DMSO, 75 MHz): δ = 159.6 (Cq of Ar), 146.0 (Cq of triazole),
129.8 (CH of triazole), 127.7 (Cq of Ar), 114.6 (CH of Ar), 102.4,
82.0 (C-1, C-4 of CD), 76.5 (Cq of Cp), 73.5, 72.9, 72.5 (C-2, C-3,
C-5 of CD), 69.7, 68.7, 66.8 (CH of Cp), 60.4 (C-6 of CD), 56.5
(CH3O-Ar), 55.6 (CH2-triazole) ppm. C171H249Fe3N9O105
(4278.39): calcd. C 49.37, H 5.95; found C 45.93, H 6.1. Mineral
impurities are most probably included.
The catalysts cannot be recycled, however, because their
amounts in the catalytic reactions are extremely low and
also because of the slow formation of Pd black, which is
essentially inactive at room temp.
Comparison with molecular catalysts indicates that such
PdNP catalysts can be used in considerably smaller
amounts than all the molecular catalysts in the Miyaura–
Suzuki reactions at room temp., but they are less robust and
less efficient than the best molecular catalysts with bro-
moarenes and chloroarene at high temperatures.
An increase in the catalytic TON of the Miyaura–Suzuki
reaction of iodobenzene at 25 °C upon decreasing the
amount of PdNP precatalyst used, high efficiency with
10 ppm PdNP in the Miyaura–Suzuki coupling reaction be-
tween PhI and PhB(OH)2 under ambient conditions, and
inhibition of catalysis by excess β-CD favor the homeo-
pathic mechanism of de Vries in which leaching atoms from
the mother precatalyst PdNPs are the active catalysts.[2d]
p-Bis(4-ferrocenyl-1,2,3-triazolylmethyl)benzene–β-Cyclodextrin:
The above procedure was extended to p-bis(4-ferrocenyl-1,2,3-tri-
azolylmethyl)benzene (30 mg, 0.049 mmol) and β-CD (123 mg,
0.108 mmol) to synthesize p-bis(4-ferrocenyl-1,2,3-triazolylmethyl)-
benzene–β-CD (b). A pale-yellow powder was obtained (131 mg,
93% yield). 1H NMR ([D6]DMSO, 300 MHz): δ = 8.21 (s, 2 H,
CH of triazole),7.31 (s, 4 H, CH of Ar), 5.76, 5.74, 5.69 (d, 28 H,
CH of CD) 5.59 (s, 4 H, Ar-CH2), 4.83, 4.47 (d and t, 28 H, CH
of CD), 4.70, 4.29, 4.01 (t, 18 H, CH of Cp), 3.63, 3.37 (m, CH of
CD) ppm. 13C NMR ([D6]DMSO, 75 MHz): δ = 146.2 (Cq of tri-
azole), 136.6 (Cq of Ar), 128.6 (CH of triazole), 121.2 (CH of Ar),
102.4, 82.0 (C-1, C-4 of CD), 76.3 (Cq of Cp), 73.5, 72.9, 72.5 (C-
2, C-3, C-5 of CD), 69.7, 68.8, 66.8 (CH of Cp), 60.4 (C-6 of CD),
52.9 (CH2-triazole) ppm. C116H168Fe2N6O70 (2878.30): calcd. C
48.41, H 5.88; found C 46.7, H 5.96.
Experimental Section
General Data: All the solvents (THF, ethanol, and DMF) and
1
chemicals were used as received. H NMR spectra were recorded
at 25 °C with a Bruker AC 200 or 300 (200 or 300 MHz) spectrome-
ter. The 13C NMR spectra were obtained in the pulsed FT mode
at 50 or 75 MHz with a Bruker AC 200 or 300 spectrometer. All
the chemical shifts are reported in parts per million (δ, ppm) with
1,3,5-Tris(4-ferrocenyl-1,2,3-triazolylmethyl)benzene–β-Cyclodex-
trin: The above procedure was extended to 1,3,5-tris(4-ferrocenyl-
1,2,3-triazolylmethyl)benzene (50 mg, 0.057 mmol) and β-CD
(214 mg, 0.189 mmol) to synthesize 1,3,5-tris(4-ferrocenyl-1,2,3-tri-
azolylmethyl)benzene–β-CD as 230 mg (0.054 mmol, 94% yield) of
1
reference to Me4Si (TMS) for the H and 13C NMR spectra. The
IR spectra were recorded with an ATI Mattson Genesis series FT-
IR spectrophotometer. The UV absorption and emission spectra
were measured with a Perkin–Elmer Lambda 19 UV/Vis spectrom-
eter and Hitachi F-2500 fluorescence spectrophotometer, respec-
tively. Gas chromatography data were recorded on a Hewlett–Pack-
ard 5890 Series II gas chromatograph equipped with a Stabilwax
(Crossband Carbowax-PEG) column and a flame ionization detec-
tor. Helium was used as the carrier gas for all substrates. The injec-
tor and detector temperatures were 240 °C. The elemental analyses
were performed by the Center of Microanalyses of the CNRS at
Lyon Villeurbanne, France. Azidomethylbenzene, p-bis(azidome-
thyl)benzene, and 1,3,5-tris(azidomethyl)benzene were synthesized
as in ref.[32] as well as the corresponding “clicked” 4-ferrocenyl-
1,2,3-triazolylmethylarene derivatives (see the Supporting Infor-
mation).
1
a pale-yellow powder. H NMR ([D6]DMSO, 300 MHz): δ = 8.13
(s, 3 H, CH of triazole), 7.20 (s, 3 H, CH of Ar), 5.71, 5.68, 5.65
(d, 42 H, CH of CD), 5.57 (s, 6 H, Ar-CH2), 4.81, 4.42 (d and t,
42 H, CH of CD), 4.66, 4.27, 4.0 (t, 27 H, CH of Cp), 3.62, 3.31
(m, CH of CD) ppm. 13C NMR ([D6]DMSO, 75 MHz): δ = 146.2
(Cq of triazole), 137.9 (Cq of Ar), 127.3 (CH of triazole), 121.2
(CH of Ar), 102.4, 82.0 (C-1, C-4 of CD), 76.3 (Cq of Cp), 73.5,
72.9, 72.5 (C-2, C-3, C-5 of CD), 69.7, 68.7, 66.8 (CH of Cp), 60.4
(C-6 of CD), 55.4 (CH2-triazole) ppm. C171H249Fe3N9O105
(4278.39): calcd. C 48.0, H 5.9; found C 46.1, H 6.3.
Preparation of the PdNPs for Catalysis: A yellow solution (2.5 mL)
of p-bis(4-ferrocenyl-1,2,3-triazolylmethyl)benzene–β-CD (2 mg,
6.95ϫ10–4 mmol, 1 equiv.) in EtOH was introduced into a Schlenk
flask and then a brown-orange aqueous solution (2.5 mL) of
K2[PdCl4] (0.45 mg, 13.9ϫ10–4 mmol, 2 equiv.) was added drop-
wise. After stirring for 10 min, NaBH4 (0.1 mg, 27.8ϫ10–4 mmol,
4 equiv.) in water (0.01 mL) was added under vigorous stirring and
the orange solution turned to the black of PdNPs (Scheme 4).
Miyaura–Suzuki Reactions: In a Schlenk flask containing freshly
prepared PdNPs, tribasic potassium phosphate (2 equiv.), phen-
ylboronic acid (1.5 equiv.), haloarene (1 equiv.), and a solution of
water/ethanol (1:1, v/v) were successively added. The suspension
was stirred under nitrogen. After the reaction time, the reaction
mixture was extracted twice with DCM (all the reactants and final
product were soluble in DCM) and the organic phase was dried
with Na2SO4 and filtered through silica gel to remove the black Pd
solid before analysis by gas chromatography.
4-Methoxy-1-(4-ferrocenyl-1,2,3-triazolylmethyl)benzene–β-Cyclo-
dextrin: The procedure in reference[10c] was carried out with the
following slight small changes. A DMF solution (5 mL) of 4-meth-
oxy-1-(ferrocenyl-1,2,3-triazolylmethyl)benzene (40 mg, 0.107
mmol) was added to a DMF solution (5 mL) of β-CD (132 mg,
0.11 mmol) in a Schlenk flask at room temperature. After stirring
for 24 h, the solvent was removed under vacuum and the crude
product, 4-methoxy-1-(ferrocenyl-1,2,3-triazolylmethyl)benzene–β-
Heck Reactions: In a Schlenk flask containing freshly prepared
PdNPs, potassium carbonate (6 equiv.), styrene (3 equiv.), haloar-
Eur. J. Inorg. Chem. 0000, 0–0
© 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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Job/Unit: I20098
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Date: 12-04-12 16:09:15
Pages: 10
L. Liang, A. K. Diallo, L. Salmon, J. Ruiz, D. Astruc
FULL PAPER
Mater. 1997, 9, 923–931; b) T. Yonezawa, N. Toshima, Polymer-
Stabilized Metal Nanoparticles: Preparation, Characterization
and Applications, in: Advanced Functional Molecules and Poly-
mers (Ed.: H. S. Nalwa), OPA, Amsterdam, 2001, vol. 2, pp.
65–86; c) L. M. Bronstein, in: Encyclopedia of Nanoscience and
Nanotechnology (Ed.: H. S. Nalwa), American Scientific Pub-
lishers, Los Angeles, 2004, vol. 7; d) C. Ornelas, A. K. Diallo,
J. Ruiz, D. Astruc, Adv. Synth. Catal. 2009, 351, 2147–2154; e)
A. Ohtaka, Y. Tamaki, Y. Igawa, K. Egami, O. Shimomura, R.
Nomura, Tetrahedron 2010, 66, 5642–5646; f) T. Teratani, A.
Ohtaka, T. Kawashima, O. Shimomura, R. Nomura, Synlett
2010, 15, 2271–2274.
a) R. M. Crooks, M. Zhao, L. Sun, V. Chechik, L. K. Yeung,
Acc. Chem. Res. 2001, 34, 181–190; b) L. Sun, R. M. Crooks,
V. Chechik, Chem. Commun. 2001, 359–360; c) E. H. Rahim,
F. S. Kamounah, J. Frederiksen, J. B. Christensen, Nano Lett.
2001, 1, 499–501; d) T. Imaoka, H. Horiguchi, K. Yamamoto,
J. Am. Chem. Soc. 2003, 125, 340–341; e) R. W. J. Scott, O. M.
Wilson, R. M. Crooks, J. Phys. Chem. B 2005, 109, 692–704.
J. Liu, J. Alvarez, W. Ong, E. Román, A. E. Kaifer, Langmuir
2001, 17, 6762–6764.
ene (1 equiv.), and a solution of water/ethanol (1:1, v/v) were suc-
cessively added. The suspension was stirred under nitrogen at 80
or 100 °C. After the given reaction time, the reaction mixture was
extracted twice with DCM (all reactants and final products were
soluble in DCM) and the organic phase was dried with Na2SO4
and filtered through silica gel to remove the black PdNPs before
analysis by gas chromatography.
Supporting Information (see footnote on the first page of this arti-
cle): Syntheses of the known precursors, 1H and 13C NMR spectra
of the known ferrocenyl precursors and new products, and the UV/
Vis spectra and TEM pictures of the PdNPs.
[8]
Acknowledgments
Financial support from the University Bordeaux 1, the Centre
National de la Recherche Scientifique (CNRS) and the Agence Na-
tionale pour la Recherche (ANR) (grant number ANR-07-CP2D-
05-01) are gratefully acknowledged.
[9]
[10]
a) E. H. Rahim, F. S. Kamounah, J. Frederiksen, J. B. Chris-
tensen, Nano Lett. 2001, 1, 499–501; b) G. Blay, I. Fernandez,
A. Monlen, M. C. Muñoz, J. R. Pedro, C. Vila, Adv. Synth.
Catal. 2009, 351, 2433–2440; c) C. Xue, K. Palaniappan, G.
Arumugam, S. A. Hackney, J. Liu, H. Liu, Catal. Lett. 2007,
116, 94–100; d) T. Matsue, D. H. Evans, T. Osa, N. Kobayashi,
J. Am. Chem. Soc. 1985, 107, 3411–3417; e) P. Li, L. Wang, H.
Li, Tetrahedron 2005, 61, 8633–8640.
[1] a) R. F. Heck, Palladium Reagents in Organic Synthesis, Aca-
demic Press, New York, 1985; b) B. Cornils, W. A. Herrmann
(Eds.), Applied Homogeneous Catalysis in Organometallic
Chemistry, Wiley-VCH, Weinheim, Germany, 1996, vol. 1 and
2; c) D. Astruc, Organometallic Chemistry and Catalysis,
Springer, Heidelberg, Germany, 2007, chapter 19.
[2] a) F. Diederich, P. J. Stang (Eds.), Metal-catalyzed Cross-cou-
pling Reactions, Wiley-VCH, Weinheim, Germany, 1998; b) J.
Grunes, J. Zhu, G. A. Somorjai, Chem. Commun. 2003, 2257–
2260; c) A. de Meijere, F. Diederich (Eds.), Metal-catalyzed
Cross Coupling Reactions, Wiley-VCH, Weinheim, Germany,
2004; d) J. G. de Vries, Dalton Trans. 2006, 421–429; e) N. T. S.
Phan, M. van der Sluys, C. J. Jones, Adv. Synth. Catal. 2006,
348, 609–679; f) D. Astruc, Anal. Bioanal. Chem. 2011, 399,
1811–1815.
[11]
[12]
[13]
[14]
I. Favier, D. Madec, E. Teuma, M. Gómez, Curr. Org. Chem.
2011, 15, 3127–3174.
J. Szejtli, Chem. Rev. 1998, 98, 1743–1754; M. V. Rekharsky, Y.
Inoue, Chem. Rev. 1998, 98, 1875–1918.
F. Hapiot, S. Tilloy, E. Monflier, Chem. Rev. 2006, 106, 767–
781.
a) F. Hapiot, A. Ponchel, S. Tilloy, E. Monflier, C. R. Chim.
2011, 14, 149–166; b) F. Wyrwalskia, B. Légera, C. Lancelota,
A. Roucoux, E. Monflier, A. Ponchel, Applied Catalysis A: Ge-
neral 2011, 391, 334–341.
L. Yin, J. Liebscher, Chem. Rev. 2007, 107, 133–173.
a) F. Shang, J. D. Glennon, J. H. T. Luong, J. Phys. Chem. C
2008, 112, 20258–20263; b) A. Harada, M. Okada, J. Li, M.
Kamachi, Macromolecules 1995, 28, 8406–8411; c) F. Man-
akker, M. Pot, T. Vermonden, C. F. Nostrum, W. E. Hennink,
Macromolecules 2008, 41, 1766–1773; d) L. C. Cesteros, C. A.
Ramírez, A. Peciña, I. Katime, Macromol. Chem. Phys. 2007,
208, 1764–1772; e) L. X. Song, L. Bai, M. X. Xu, J. He, S. Z.
Pan, Coord. Chem. Rev. 2009, 253, 1276–1284; f) J. Wu, H. He,
C. Gao, Macromolecules 2010, 43, 2252–2260.
a) J. D. Senra, L. F. B. Malta, A. L. F. Souza, L. C. S. Aguiar,
O. A. C. Antunes, Adv. Synth. Catal. 2008, 350, 2551–2558; b)
J. D. Senra, L. F. B. Malta, M. E. H. M. Costa, R. C. Michel,
L. C. S. Aguiar, A. B. C. Simas, O. A. C. Antunes, Adv. Synth.
Catal. 2009, 351, 2411–2422.
a) J. Liu, R. Xu, A. E. Kaifer, Langmuir 1998, 14, 7337–7339;
b) J. Liu, W. Ong, E. Román, M. J. Lynn, A. E. Kaifer, Lang-
muir 2000, 16, 3000–3002; c) J. Liu, S. Mendoza, E. Román,
M. J. Lynn, R. Xu, A. E. Kaifer, J. Am. Chem. Soc. 1999, 121,
4304–4305; d) N. Badi, P. Guégan, F.-X. Legrand, L. Leclercq,
S. Tilloy, E. Monflier, J. Mol. Catal. A 2010, 318, 8–14.
a) P. Gou, W. Zhu, Z. Shen, Biomacromolecules 2010, 11, 934–
943; b) S. Salmaso, A. Semenzato, S. Bersani, P. Matricardi, F.
Rossi, P. Caliceti, Int. J. Pharm. 2007, 345, 42–50.
a) D. Harries, D. C. Rau, V. A. Parsegian, J. Am. Chem. Soc.
2005, 127, 2184–2190; b) F. Manakker, T. Vermonden, C. F.
Nostrum, W. E. Hennink, Biomacromolecules 2009, 10, 3157–
3175.
[3] R. F. Heck, Acc. Chem. Res. 1979, 12, 146–151; A. B. Dounay,
L. E. Overman, Chem. Rev. 2003, 103, 2945–2964.
[15]
[16]
[4] a) N. Miyaura, A. Suzuki, Chem. Rev. 1995, 95, 2457–2483; b)
J. Hassan, M. Sévignon, C. Gozzi, E. Schulz, M. Lemaire,
Chem. Rev. 2002, 102, 1359–1469; c) A. Suzuki, in: Modern
Arene Chemistry (Ed.: D. Astruc), Wiley-VCH, Weinheim,
2002, pp. 53–106.
[5] a) M. T. Reetz, W. Helbig, S. A. Quaiser, in: Active Metals:
Preparation, Characterizations, Applications (Ed.: A. Fürstner),
VCH, Weinheim, Germany, 1996, p. 279; A. Roucoux, J.
Schulz, H. Patin, Chem. Rev. 2002, 102, 3757–3778; b) H.
Bönnemann, R. Richards, Synth. Methods Organomet. Inorg.
Chem. 2002, 10, 209; c) M. Moreno-Mañas, R. Pleixats, Acc.
Chem. Res. 2003, 36, 638–643; d) D. Astruc, F. Lu, J. Ruiz, D.
Astruc, Angew. Chem. 2005, 117, 8062; Angew. Chem. Int. Ed.
2005, 44, 7852–7872; e) D. Astruc, Inorg. Chem. 2007, 46,
1884–1894; f) D. Astruc (Ed.), Nanoparticles and Catalysis,
Wiley-VCH, Weinheim, Germany, 2008.
[6] a) L. D. Rapino, F. F. Nord, J. Am. Chem. Soc. 1941, 63, 2745;
b) L. D. Rapino, F. F. Nord, J. Am. Chem. Soc. 1941, 63, 3268;
c) K. E. Kavanagh, F. F. Nord, J. Am. Chem. Soc. 1943, 65,
2121–2125; d) P. Li, L. Wang, H. Li, Tetrahedron 2005, 61,
8633–8640; e) J. Athilakshmi, S. Ramanathan, D. K. Chand,
Tetrahedron Lett. 2008, 49, 5286–5288; f) M. B. Thathagar, P. J.
Kooyman, R. Boerleider, E. Jansen, C. J. Elsevier, G. Rothen-
berg, Adv. Synth. Catal. 2005, 347, 1965–1968; g) M. B.
Thathagar, J. E. Elshof, G. Rothenberg, Angew. Chem. 2006,
118, 2952; Angew. Chem. Int. Ed. 2006, 45, 2886–2890; h) I.-
K. Park, H. A. Recum, S. Jiang, S. H. Pun, Langmuir 2006,
22, 8478–8484; i) A. V. Gaikwad, G. Rothenberg, Phys. Chem.
Chem. Phys. 2006, 8, 3669–3675.
[17]
[18]
[19]
[20]
[21]
[22]
B. Siegel, R. Breslow, J. Am. Chem. Soc. 1975, 97, 6869.
a) P. D. Beer, Acc. Chem. Res. 1998, 31, 71–80; b) F.-S. Sharon,
I. Turyan, D. Mandler, D. Avnir, S. Marx, Langmuir 2005, 21,
[7] a) M. V. Seregina, L. M. Bronstein, O. A. Platonova, D. M.
Chernyshov, P. M. Valetsky, J. Hartmann, E. A. Wenz, Chem.
8
www.eurjic.org
© 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 0000, 0–0

Job/Unit: I20098
/KAP1
Date: 12-04-12 16:09:15
Pages: 10
Catalysis of C–C Cross-Coupling Reactions
7842–7847; c) D. Astruc, C. Ornelas, J. Ruiz, Acc. Chem. Res.
2008, 41, 841–856.
[23] L. Cui, S. Gadde, W. Li, E. A. Kaifer, Langmuir 2009, 25,
13763–13769.
[24] a) J. A. Fernandes, S. Lima, S. S. Braga, P. Ribeiro-Claro, J. E.
Rodriguez-Borges, C. Teixeira, M. Pillinger, J. J. C. Teixeira-
Dias, S. I. J. Gonçalves, J. Organomet. Chem. 2005, 690, 4801–
4808; b) O. Buriez, J. M. Heldt, E. Labbé, A. Vessières, G. Ja-
ouen, C. Amatore, Chem. Eur. J. 2008, 14, 8195–8203; c) J. M.
Casas-Solvas, E. Ortiz-Salmeron, I. Fernandez, L. Garcia-Fu-
entes, F. Santoyo-Gonzalez, A. Vargas-Berenguel, Chem. Eur.
J. 2009, 15, 8146–8162.
[29] a) E. Boisselier, A. K. Diallo, L. Salmon, J. Ruiz, D. Astruc,
Chem. Commun. 2008, 4819–4821; b) E. Boisselier, A. K. Di-
allo, L. Salmon, C. Ornelas, J. Ruiz, D. Astruc, J. Am. Chem.
Soc. 2010, 132, 2729–2742; c) M.-C. Daniel, D. Astruc, Chem.
Rev. 2004, 104, 293–346.
[30] a) C. Ornelas, J. Ruiz, L. Salmon, D. Astruc, Adv. Synth. Catal.
2008, 350, 837–845; b) C. Ornelas, A. K. Diallo, J. Ruiz, D.
Astruc, Adv. Synth. Catal. 2009, 351, 2147–2154; c) D. Astruc,
L. Liang, A. Rapakousiou, J. Ruiz, Acc. Chem. Res. 2012.
ASAP, DOI: 10.1021/ar200235m.
[31] Y. Chen, Y. Liu, R. Guo, J. Colloid Interface Sci. 2009, 336,
766–772.
[25] L. Strimbu, J. Liu, A. E. Kaifer, Langmuir 2003, 19, 483–485.
[26] M. Ferreira, H. Bricout, A. Sayede, A. Ponchel, S. Fourmentin,
S. Tilloy, E. Monflier, Adv. Synth. Catal. 2008, 350, 609–618.
[27] a) C. Ornelas, J. Ruiz, E. Cloutet, S. Alves, D. Astruc, Angew.
Chem. 2007, 119, 890; Angew. Chem. Int. Ed. 2007, 46, 872–
877; b) C. Ornelas, L. Salmon, J. Ruiz, D. Astruc, Chem. Com-
mun. 2007, 4946–4948; c) A. Diallo, C. Ornelas, J. Ruiz, L.
Salmon, D. Astruc, Angew. Chem. 2007, 119, 8798; Angew.
Chem. Int. Ed. 2007, 46, 8644–8648; d) C. Ornelas, L. Salmon,
J. Ruiz, D. Astruc, Chem. Eur. J. 2008, 14, 50–64.
[32] S. Badèche, J.-C. Daran, J. Ruiz, D. Astruc, Inorg. Chem. 2008,
47, 4903–4908.
[33] I. Favier, S. Massou, E. Teuma, K. Philippot, B. Chaudret, M.
Gómez, Chem. Commun. 2008, 3296–3298.
[34] I. P. Beletskaya, A. Cheprakov, Chem. Rev. 2000, 100, 3009–
3066.
[35] M. T. Reetz, E. Westermann, Angew. Chem. 2000, 112, 170;
Angew. Chem. Int. Ed. 2000, 39, 165–168; M. T. Reetz, J. G.
de Vries, Chem. Commun. 2004, 1559–1563.
[36] J. G. de Vries, A. H. de Vries, Eur. J. Org. Chem. 2003, 799–804.
[28] S. Gatard, L. Liang, L. Salmon, J. Ruiz, D. Astruc, S. Bouquil-
lon, Tetrahedron Lett. 2011, 52, 1842–1846.
Received: January 31, 2012
Published Online: ᭿
Eur. J. Inorg. Chem. 0000, 0–0
© 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
9

Job/Unit: I20098
/KAP1
Date: 12-04-12 16:09:15
Pages: 10
L. Liang, A. K. Diallo, L. Salmon, J. Ruiz, D. Astruc
FULL PAPER
Pd Nanoparticle Catalysts
Water-soluble “clicked” assemblies con-
taining two or three cyclodextrin-encapsu-
lated ferrocenyl termini and 1,2,3-triazolyl
internal ligands for PdII are precursors of
stabilized Pd0 nanoparticle precatalysts for
efficient Miyaura–Suzuki and Heck reac-
tions of iodobenzene in water/ethanol un-
der mild conditions.
L. Liang, A. K. Diallo, L. Salmon, J. Ruiz,
D. Astruc* ....................................... 1–10
Catalysis of C–C Cross-Coupling Reac-
tions in Aqueous Solvent by Bis- and Tris-
(ferrocenyltriazolylmethyl)arene–β-Cyclo-
dextrin-Stabilized Pd0 Nanoparticles
Keywords: Cyclodextrins / Nanoparticles /
Palladium / Heterogeneous catalysis / C–C
coupling / Click chemistry /
Sandwich complexes
10
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