The use of palladium nanoparticles supported on graphene oxide in the Mizoroki-Heck reaction

Article abstract of DOI:10.1134/S0036023613040062

We have developed a convenient single-step method for producing palladium nanoparticles on the surface of graphene oxide by reducing palladium chloride with NaBH₄. According to transmission electron microscopy data, palladium nanoparticles have

Full text of DOI:10.1134/S0036023613040062

ISSN 0036ꢀ0236, Russian Journal of Inorganic Chemistry, 2013, Vol. 58, No. 4, pp. 392–394. © Pleiades Publishing, Ltd., 2013.
Original Russian Text © Yu.V. Ioni, S.E. Lyubimov, V.A. Davankov, S.P. Gubin, 2013, published in Zhurnal Neorganicheskoi Khimii, 2013, Vol. 58, No. 4, pp. 451–453.
SYNTHESIS AND PROPERTIES
OF INORGANIC COMPOUNDS
The Use of Palladium Nanoparticles Supported on Graphene Oxide
in the Mizoroki–Heck Reaction
Yu. V. Ionia, S. E. Lyubimovb, V. A. Davankovb, and S. P. Gubina
a Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences,
Leninskii pr. 31, Moscow, 119991 Russia
b Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences,
ul. Vavilova 28, Moscow, 119991 Russia
Received May 2, 2012
Abstract—We have developed a convenient singleꢀstep method for producing palladium nanoparticles on the
surface of graphene oxide by reducing palladium chloride with NaBH4. According to transmission electron
microscopy data, palladium nanoparticles have a spheroidal shape; their sizes are 6–8 nm. The tests of immoꢀ
bilized palladium nanoparticles have shown that they exhibit high activity in the Mizoroki–Heck crossꢀcouꢀ
pling reaction.
DOI: 10.1134/S0036023613040062
The Mizoroki–Heck crossꢀcoupling reaction
PhX
Pd/GO
Ph
R
R
between arylhalides and olefins is a commonly used
tool in organic synthesis [1–3]. Despite the fact that
homogeneous metal complexes are actively used in
this reaction [4, 5], it has recently been reported that
palladium nanoparticles obtained on various supports
(alumina [6, 7], silicon [8, 9], chitosan [10], etc.) can
also be employed in this reaction. The search for new
efficient supports for metal catalytically active nanoꢀ
particles is a challenge for researchers. Graphene,
which consists of monolayers of carbon atoms linked
together via sp2ꢀhybridized carbon atoms, is one of the
promising supports for nanoparticles [11]. However,
the original method for producing graphene, which
was invented by Novoselov and Geim and consists in
peeling the layers of highly oriented pyrolytic graphite,
is extremely laborꢀintensive and allows obtaining only
small amounts of graphene. The later procedures for
producing graphene involve several steps; strong and
toxic reducing agents or high temperatures are to be
used in them. However, the composition and properꢀ
ties of the resulting material differ from those of singleꢀ
layer graphene [12]. Meanwhile, there are a number of
synthetically available graphene derivatives. One of
those, graphene oxide, can also be used as a template
for catalytically active nanoparticles. The composites
represented by palladium nanoparticles supported on
graphene oxide have already shown themselves to act
as efficient catalysts in the reactions of crossꢀcoupling
of phenylboronic acid with a number of arylbromides
and iodides [13, 14] and in electrooxidation of methaꢀ
nol [15].
Scheme. Mizoroki–Heck crossꢀcoupling reaction
of arylhalides and olefins.
The production of palladium nanoparticles supꢀ
ported on graphene oxide is reported and the results of
studying these samples as a catalyst in the reaction of
crossꢀcoupling of arylhalides and olefins are presented
in this work.
EXPERIMENTAL
The content of palladium nanoparticles supported
on graphene oxide was determined by Xꢀray fluoresꢀ
cence analysis on a VRAꢀ30 Zeiss Jena spectrometer.
TEM data were obtained using a JEMꢀ1011 electron
microscope at an accelerating voltage of 80 kV.
Preparation of palladium nanoparticles supported
on graphene oxide. Palladium chloride (40 mg) was
dissolved in a mixture of water (2 mL) and concenꢀ
trated hydrochloric acid (0.2 mL). The mixture was
added to graphene oxide (560 mg) prepared using the
Hummers method under stirring. After the aqueous
phase became transparent (in 25 min), an excess of dry
NaBH4 (230 mg) was added in portions (10–20 mg).
After stirring for 30 min, the solid precipitate was
washed with water (50 mL) and acetone (20 mL) and
dried under vacuum to obtain black finely divided
shiny powder.
Reaction of crossꢀcoupling of arylhalides with oleꢀ
fins. 1 mmol olefin, 2.5 mmol arylhalide, 3 mmol forꢀ
mic acid, 3 mmol triethylamine, and 32 mg of the catꢀ
alyst (0.0054 mmol Pd) was added to 5 mL of the corꢀ
responding solvent (see table). The reaction mixture
392

THE USE OF PALLADIUM NANOPARTICLES SUPPORTED
Mizoroki–Heck crossꢀcoupling reaction of arylhalides and olefins (5 h)
393
Exp. no.
R
X
Solvent
Toluene
Base
Additive
Conversion, %
1
2
3
4
5
6
7
8
9
Ph
Ph
Ph
Ph
I
NEt3
NEt3
NEt3
NEt3
NEt3
NEt3
NEt3
NEt3
NEt3
–
62
81
99
63
95
70
95
49
82
I
Toluene
Toluene
Toluene
Toluene
Toluene
CH3COOH
HCOOH
HCOOH
HCOOH
HCOOH
HCOOH
HCOOH
HCOOH
I
Br
I
4ꢀMeꢀPh
4ꢀ
4ꢀ
i
PrꢀPh
PrꢀPh
I
i
I
p
ꢀxylene
Toluene
ꢀxylene
2ꢀNaphthyl
2ꢀNaphthyl
I
I
p
was stirred for 5 h at the boiling point of the solvent, donor methyl substituent (Cf. exp. 3 and 5). The use of
diluted with water, extracted with benzene, dried using 4ꢀisopropylstyrene with stronger donating properties
Na2SO4, stripped, and analyzed by gas chromatograꢀ
phy (GC) and 1H NMR spectroscopy after the syntheꢀ
sis products were isolated using column chromatograꢀ
phy as published [16–18].
resulted in a further loss of conversion (exp. 6). The
replacement of toluene by
ꢀxylene, which has a
higher boiling point, allowed us to increase the degree
of conversion (Cf. exp. 6 and 7). This was valid for
p
2ꢀvinylnaphthalene as well. Thus, the use of pꢀxylene
in this case made it possible to increase the degree of
conversion (exp. 8 and 9).
RESULTS AND DISCUSSION
Palladium nanoparticles were produced via the
sorption of tetrachloropalladium acid, which was
formed by reacting palladium chloride and HCl soluꢀ
tion, on graphene oxide followed by its reduction with
an excess of NaBH4 (see Experimental section). Xꢀray
fluorescence analysis demonstrated that the palladium
content on graphene oxide was 1.8%. The TEM
assessing of the size and shape of palladium nanoparꢀ
ticles showed that the nanoparticles have a spheroidal
shape; their size being 6–8 nm (figure).
In summary, we catalyzed the Mizoroki–Heck
reaction with palladium nanoparticles supported on
graphene oxide for the first time. The rate of the reacꢀ
tion was found to be significantly increased when an
equimolar mixture of triethylamine with organic acids
was used. Meanwhile, the use of solvents with high
boiling points can also increase the degree of converꢀ
sion.
The resulting catalyst containing palladium nanoꢀ
particles was initially tested in the reaction of crossꢀ
coupling of styrene and iodobenzene in toluene. When
using triethylamine as a base, 62% degree of converꢀ
sion was achieved within 5 h. We also investigated the
use of an equimolar triethylamine–acetic acid mixture
in this reaction. As it was shown previously [19], these
conditions made it possible to increase the degree of
conversion in case when phosphorusꢀcontaining denꢀ
drimers were used as ligands. It turned out that the
degree of conversion could be successfully increased in
our case, as well (from 62 to 81%; table, exp. 1 and 2).
It is of interest that proceeding from acetic acid to forꢀ
mic acid allowed us to increase the degree of converꢀ
sion almost to quantitative values (exp. 3). Replaceꢀ
ment of iodobenzene by bromobenzene resulted in a
decrease in the degree of conversion, which was due to
a lower reactivity of the latter.
100 nm
The use of substituted styrenes in this reaction with
iodobenzene as an arylating agent was also studied.
The degree of conversion was found to slightly
decrease when using 4ꢀmethylstyrene containing a
Micrograph of palladium nanoparticles supported on
graphene oxide surface.
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 58 No. 4 2013

394
IONI et al.
11. K. Novoselov, A. Geim, S. Morosov, et al., Science 306
,
REFERENCES
666 (2004).
1. M. Oestreich, The Misoroki
Chichester, 2009).
⎯Heck Reaction (Wiley,
12. S. Gubin and S. Tkachev, in Graphene and Related Carꢀ
bon Nanospecies (LIBROKOM, Moscow, 2012), p. 104
[in Russian].
2. V. Polshettiwar and A. Molnar, Tetrahedron 64, 6949
(2007).
13. G. M. Scheuermann, L. Rumi, P. Steurer, et al., J. Am.
3. M. Shibasaki, E. M. Vogl, and T. Ohshima, Adv. Synth.
Chem. Soc. 131, 8262 (2009).
Catal. 346, 1533 (2004).
4. M. L. Kantam, P. Srinivas, S. Bhargava, et al., J. Orgaꢀ
14. H.ꢀW. Ha, I. Kim, S.ꢀJ. Hwang, and R. S. Ruoff, Elecꢀ
nomet. Chem. 74, 4882 (2009).
trochem. SolidꢀState Lett. 14, B70 (2011).
5. A. Deagostino, C. Prandi, S. Tabasso, and P. Venꢀ
15. W. Hummers and R. Offeman, J. Am. Chem. Soc.
1339 (1958).
6,
turello, Molecules 15, 2667 (2010).
6. E. Mieczyn
' ska and A. M. Trzeciak, Molecules 15,
16. A. R. Hajipour, K. Karami, A. Pirisedigh, and
2166 (2010).
A. E. Ruoho, J. Organomet. Chem. 694, 2548 (2009).
7. E. Mieczynska, A. Gnieweka, M. Zawadzki, et al.,
Appl. Catal. A: Gen. 393, 195 (2011).
8. B. Tamami, H. Allahyari, and S. Ghasemi, J. Orgaꢀ
17. S. Wu, H. Ma, X. Jia, et al., Tetrahedron 67, 250
(2011).
nomet. Chem. 696, 594 (2011).
9. P. Wang, Q. Lu, and J. Li, Catal. Lett. 131, 444 (2009).
18. R. C. Smith, C. Bodner, J. Protasiewicz, et al., J. Orgaꢀ
nomet. Chem. 690, 477 (2005).
10. B. C. E. Makhubela, A. Jardine, and G. S. Smith, Appl. 19. D. P. Catsoulacos, B. R. Steele, C. G. Screttas, et al.,
Catal., A 393, 231 (2011).
Tetrahedron Lett. 44, 4575 (2003).
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 58 No. 4 2013