Synthesis and X-ray structural characterization of a bidendate phosphine (dppe) palladium(II) complex and its application in Stille and Suzuki cross-coupling reactions

Article abstract of DOI:10.1002/aoc.3533

The synthesis, characterization, crystal structure and catalyst activity of the bidentate phosphine complex [1,2-bis(diphenylphosphino)ethane]palladium(II) bromide, [PdBr₂(dppe)], are presented. Treatment of 1,2-bis(diphenylphosphino)ethane with palladium(II) bromide under mild conditions resulted in the compound in high yield and purity. The characterization of the synthesized compound was performed using spectroscopic methods, such as Fourier transform infrared and NMR, CHN analysis and X-ray crystallography. The structure of the compound was slightly distorted square planar. This compound was found to work as an efficient catalyst for both Stille and Suzuki cross-coupling reactions of various aryl halides with triphenyltin chloride and/or phenylboronic acid. Also, the catalyst could be recovered and reused several times without significant loss of its catalytic activity. Copyright

Full text of DOI:10.1002/aoc.3533

Full paper
Received: 6 March 2016
Revised: 3 May 2016
Accepted: 8 May 2016
Published online in Wiley Online Library
(wileyonlinelibrary.com) DOI 10.1002/aoc.3533
Synthesis and X-ray structural characterization
of a bidendate phosphine (dppe) palladium(II)
complex and its application in Stille and Suzuki
cross-coupling reactions
Ali Naghipoura*, Arash Ghorbani-Choghamarania, Heshmatollah Babaeea
and Behrouz Notashb
The synthesis, characterization, crystal structure and catalyst activity of the bidentate phosphine complex [1,2-bis
(diphenylphosphino)ethane]palladium(II) bromide, [PdBr2(dppe)], are presented. Treatment of 1,2-bis(diphenylphosphino)eth-
ane with palladium(II) bromide under mild conditions resulted in the compound in high yield and purity. The characterization
of the synthesized compound was performed using spectroscopic methods, such as Fourier transform infrared and NMR, CHN
analysis and X-ray crystallography. The structure of the compound was slightly distorted square planar. This compound was found
to work as an efficient catalyst for both Stille and Suzuki cross-coupling reactions of various aryl halides with triphenyltin chloride
and/or phenylboronic acid. Also, the catalyst could be recovered and reused several times without significant loss of its catalytic
activity. Copyright © 2016 John Wiley & Sons, Ltd.
Additional supporting information may be found in the online version of this article at the publisher’s web site.
Keywords: crystal structure; phosphonium; palladium; Stille reaction; Suzuki cross-coupling
science,[18] pharmaceuticals and bioactive compounds.[19] Clear ad-
vantages over other palladium-catalysed cross-coupling reactions
Introduction
Phosphine compounds are a group of species with very specific
and interesting physical and donor–acceptor properties, among
which stands out their high stability, which is conferred on the
metal complexes that they form. Because of thermal stability and
robustness, phosphine combinations have attracted the continu-
ous attention of the chemistry community for multiple applications,
this being specifically true in the case of homogeneous catalysis.[1–4]
The expansion of new phosphine ligands has a great effect in
continuing to attract much interest,[5–8] particularly in transition
metal-catalysed organic reactions.[9,10]
The success of phosphine ligands in catalysis is a function of both
electronic and steric properties, and it is advantageous to be able to
vary both autonomously. This allows good tuning of the coordi-
nated species, thus enabling the diverse steps of a catalytic cycle
to be optimized.[11] 1,2-Bis(diphenylphosphino)ethane (dppe) and
triphenylphosphine are typical mono- and bidentate phosphine li-
gands, respectively, which are used most frequently in a wide vari-
ety of homogeneous catalysts.[12] A good deal of knowledge about
the performance of dppe and triphenylphosphine as ligands has
been accumulated for much transition metal catalysis. Lately, Schiff
bases have been recognized as good alternatives to phosphines in
Suzuki reactions.[13]
include: (i) tolerance towards various functional groups; (ii) mild re-
action conditions; and (iii) low toxicity of starting materials and by-
products.[20] Suzuki cross-coupling reactions with heterogeneous
nano-palladium catalysts have been studied by several
researchers.[21] Triphenyltin chloride (TPTCl) is a very good reagent
in organic synthesis such as thioetherification[22] and C&bond;C
coupling reactions.[23] Although TPTCl has been applied as a useful
reagent for the synthesis of sulfides through C&bond;S coupling
reactions,[24] it was shown to be toxic to the rotifer Brachionus
koreanus across different levels of biological organization,[25] and
should be handled with care. To prevent environmental toxicity,
one can detoxify the final waste including TPTCl by common
method and direct photolysis.[26]
In this paper, we report the synthesis, characterization and
crystal structure determination of the complex [1,2-bis
(diphenylphosphino)ethane]palladium(II) bromide, [PdBr2(dppe)],
as a novel and efficient catalyst for C&bond;C bond formation in
*
Correspondence to: A. Naghipour, Department of Chemistry, Faculty of Science,
Ilam University, PO Box 69315516, Ilam, Iran. E-mail: naghipour2002@yahoo.com
Palladium-catalysed coupling reactions such as Stille and Suzuki
cross-coupling reactions have become an extremely strong
method for the formation of C&bond;C bonds in organic
synthesis,[14–16] biologically active compounds,[17] materials
a Department of Chemistry, Faculty of Science, Ilam University, POBox 69315516,
Ilam, Iran
b Department of Chemistry, Shahid Beheshti University, Tehran, Iran
Appl. Organometal. Chem. (2016)
Copyright © 2016 John Wiley & Sons, Ltd.

A. Naghipour et al.
coupling reactions in the presence of TPTCl (Stille reaction) and
phenylboronic acid (Suzuki reaction) under mild reaction
conditions.
was extracted with water and diethyl ether. The organic layer was
dried over magnesium sulfate and then evaporated under reduced
pressure. The products may be purified by column chromatography
on silica gel using ethyl acetate–n-hexane (3:7) if necessary.
Experimental
Results and Discussion
Materials and Physical Measurements
To the best of our knowledge, there is no report of the complex
[PdBr2(dppe)]. This monochelated complex was easily synthesized
by reaction of 1,2-bis(diphenylphosphino)ethane with palladium
(II) bromide in 1:1 molar ratio in toluene at room temperature for
24 h, leading to the formation of a yellow solid as shown in
Scheme 1. The observed singlet peak at 30.53 ppm in the 31P
NMR spectrum confirmed the purity of the product.
The required chemicals were obtained from Merck and Aldrich and
were used without further purification. Melting points were mea-
sured with a Stuart SMP3 apparatus. Infrared (IR) spectra in the
range 400–4000 cmÀ1 were recorded with a Shimadzu 435-U-04
spectrophotometer and samples were prepared as KBr pellets.
NMR spectra (1H, 13C and 31P) were recorded with a 400 MHz Bruker
spectrometer in CDCl3 as the solvent at room temperature. Elemen-
tal analysis was carried out with a CHNS-O Costech ECS 4010
analyser. TLC was performed using Merck silica gel 60 F254 pre-
coated plates (0.25 mm) and visualized using a UV fluorescence
lamp.
X-ray Crystallographic Study of [PdBr2(dppe)]
Suitable crystals of [PdBr2(dppe)] were obtained by slow evapora-
tion over several days from chloroform solution. Its structure was
determined using single-crystal X-ray diffraction. The molecular
structure of the neutral palladium(II) complex is shown in Fig. 1.
The complex crystallizes in the monoclinic space group P21/c with
four molecules in the unit cell. The asymmetric unit consists of one
palladium(II) cation, two bromine anions and one dppe ligand, with
all atoms in general positions.
X-ray Crystallography
Single-crystal X-ray diffraction data of suitable crystals were col-
lected with a STOE IPDS-II diffractometer at 120(2) K, using graphite
monochromated Mo Kα radiation (0. 0.71073 Å). The data collection
was performed using the ω-scan technique and using the STOE X-
AREA software package,[27] whereas data reduction was carried out
using the program X-RED.[28] The structure was solved by direct
methods and subsequent difference Fourier maps and then refined
on F2 by full-matrix least-squares procedures using the programs
SHELX and SHELXL, respectively,[29] and all refinements were per-
formed using the X-STEP32 crystallographic software package.[30]
All hydrogen atoms were added in geometrically idealized
positions.
Scheme 1. Synthesis of [PdBr2(dppe)].
Synthesis of [PdBr2(dppe)]
Refluxing diphenylphosphinoethane (597 mg, 1.5 mmol) and palla-
dium(II) bromide (399 mg, 1.5 mmol) at room temperature in a mo-
lar ratio of 1:1 in toluene for 6 h gave a yellowish precipitate, which
was extracted from the obtained suspension. Suitable yellowish
crystals for X-ray diffraction analysis were obtained by slow addition
of methanol to a chloroform solution containing the compound.
Yield 132 mg, 85%; m.p. 194 °C. Anal. Calcd for C26H24P2PdBr2
(665.87 g molÀ1) (%): C, 46.98; H, 3.64. Found (%): C, 46.81; H, 3.58.
IR (KBr disc, ν, cmÀ1): 3143–3100 (C&bond;H in Ph), 1585–1608
(C&dbond;C in Ph), 1400.1 (P&bond;CH2). 1H NMR (400 MHz,
DMSO-d6, δ, ppm): 3.82 (br, 4H, CH2P), 7.08–7.9 (m, 20H, Ph). 13C
NMR (100 MHz, DMSO-d6, δC, ppm): 70.22, (br, DMSO-d6), 35.17 (d,
J = 16.03, CH2P), 128.8, 130.01, 130.5, 132.1, (d, J = 17.63, Ph). 31P
{1H} NMR (162 MHz, DMSO-d6, δP, ppm): 30.53 (s, PPh2).
General Procedure for Stille and Suzuki Cross-Coupling
Reactions
Aryl halide (0.5 mmol) and K2CO3 (1.5 mmol) were added to PEG-
400. To this mixture, 3 mg of [PdBr2(dppe)] was added and heated
at 90 °C in an oil bath. Finally, 0.5 mmol of phenylating reagent
(TPTCl or phenylboronic acid) was added and the reaction mixture
was vigorously stirred. The progress of the reaction was monitored
by TLC. After completion of the reaction, the corresponding biphe-
nyl product was separated by filtration and the reaction mixture
Figure 1. X-ray structure of [PdBr2(dppe)].
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Appl. Organometal. Chem. (2016)

Synthesis of [PdBr2(dppe)] and its application in C C bond formation
Table 1. Crystal data and structure refinement for [PdBr2(dppe)]
[PdBr2(dppe)]
Empirical formula
C26H24Br2P2Pd
664.59
Formula weight
Temperature (K)
120(2)
Wavelength (Å)
0.71073
Crystal system
Monoclinic
P21/c
Space group
Unit cell dimensions
a (Å)
11.092(2)
Figure 2. Reuse of the catalyst in Suzuki cross-coupling reaction.
b (Å)
13.293(3)
c (Å)
16.747(3)
geometry with PdP2Br2 surroundings (Fig. 2). Considering the differ-
ence between the angles Br(2)–Pd(1)–P(1) of 90.67(5)° and Br(1)–
Pd(1)–P(2) of 89.80(6)° shows that the Pd atom is slightly out of
the plane of the molecule. The smaller than ideal P–Pd–P angle
leads to an opening of the Br–Pd–Br angle to 94.52(3)°. Compari-
son of Pd&bond;Br (2.4859 Å) and Pd&bond;P (2.2385 Å) average
distances and Br(1)–Pd(1)–Br(2) (94.52(3)°) and P(2)–Pd(1)–P(1)
(85.43(7)°) angles in [Pd(dppe)Br2] shows a significant difference be-
tween these two bond lengths and angles.
α (°)
β (°)
90.00
99.55(3)
γ (°)
90.00(3)
Volume (Å3)
2435.1(9)
Z
4
Calculated density (Mg mÀ3
)
1.813
F(000)
1304
Theta range for data collection (°)
Limiting indices
2.47 to 29.15
À10 ≤ h ≤ 15, À16 ≤ k ≤ 18,
22 ≤ l ≤ 22
Completeness to θ = 29.15°
99.5%
Catalytic Study
Absorption correction
Numerical
Absorption coefficient (mmÀ1
Crystal size (mm3)
)
4.188
The catalytic activity of the palladium catalyst [PdBr2(dppe)] was ex-
amined in C&bond;C bond formation reactions. Initially the Stille re-
action was studied. To this end, the cross-coupling reaction of aryl
halides with TPTCl was considered. In order to find ideal reaction
conditions we studied the effect of various parameters on the out-
come of the reaction such as the amount of catalyst and the nature
of base and solvent in the reaction of iodobenzene with Ph3SnCl as a
model reaction. The reaction conditions were optimized, and the re-
sults are summarized in Table 3.
The model reaction was carried out in the presence of various
solvents and bases and different amounts of reactants and catalyst.
As evident from Table 3, the product yield increases with increasing
amount of catalyst (Table 3, entries 1–3). Also, the yield decreases
when the amount of catalyst increases from 3 to 4 mg (Table 3, en-
tries 3 and 4). Consequently, 3 mg of [PdBr2(dppe)] (Table 3, entry 3)
0.35 × 0.25 × 0.10
16 389/6539 [R(int) = 0.1222]
0.6795 and 0.3219
Full-matrix least-squares on F2
6539/0/280
Reflections collected/unique
Max. and min. Transmission
Refinement method
Data/restraints/ parameters
Goodness-of-fit on F2
1.013
Final R indices [I > 2σ(I)]
R indices (all data)
Largest diff. Peak and hole (e ÅÀ3
R1 = 0.698, WR2 = 0.1299
R1 = 0.1236, WR2 = 0.1470
1.046 and À0.972
)
Relevant parameters concerning refinement and data collection
are given in Table 1 and selected bond distances and angles are
given in Table 2. Furthermore, crystallographic data for the struc-
ture in this paper can be found in the supporting information.
The Pd(II) centre is chelated by two bromo ligands and two phos-
phine groups of the dppe ligand in a distorted square planar
Table 3. Optimization of reaction parameters for Stille cross-coupling
reaction of iodobenzene withPh3SnCl
Entry Cat. (mg) Solvent Base Temp. (°C) Time (min) Yield (%)a
1
1
2
3
4
3
3
3
3
3
3
3
3
3
3
PEG
PEG
PEG
PEG
PEG
PEG
PEG
PEG
EtOH
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
90
90
90
90
r.t.
50
70
110
90
90
90
90
90
90
65
50
83
89
96
94
—
80
84
87
90
86
76
90
88
86
Table 2. Selected bond lengths and bond angles for [PdBr2(dppe)]
2
Bond lengths (Å)
Bond angles (°)
3
30
4
35
Pd(1)–Br(1)
2.4790(11)
2.4928(13)
2.2428(18)
2.2342(19)
1.816(7)
P(2)–Pd(1)–P(1)
85.43(7)
89.80(6)
174.17(5)
171.05(5)
90.67(5)
94.52(3)
111.8(2)
117.1(2)
108.5(2)
113.9(1)
115.3(2)
106.8(2)
5
—
Pd(1)–Br(2)
Pd(1)–P(1)
Pd(1)–P(2)
P(1)–C(6)
P(2)–Pd(1)–Br(1)
P(1)–Pd(1)–Br(1)
P(2)–Pd(1)–Br(2)
P(1)–Pd(1)–Br(2)
Br(1)–Pd(1)–Br(2)
C(6)–P(1)–Pd(1)
C(12)–P(1)–Pd(1)
C(13)–P(1)–Pd(1)
C(21)–P(2)–Pd(1
C(20)–P(2)–Pd(1)
C(14)–P(2)–Pd(1)
6
125
95
7
8
35
9
85
P(1)–C(12)
P(1)–C(13)
P(2)–C(14)
P(2)–C(20)
P(2)–C(21)
C(1)–C(6)
C(1)–C(2)
1.822(8)
10
11
12
13
14
DMSO K2CO3
120
180
60
1.819(5)
DMF
PEG
PEG
PEG
K2CO3
NaOAc
KHCO3
Et3N
1.842(7)
1.817(5)
75
1.819(7)
80
1.386(9)
aIsolated yield.
1.390(10)
Appl. Organometal. Chem. (2016)
Copyright © 2016 John Wiley & Sons, Ltd.
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A. Naghipour et al.
was chosen as optimal amount of catalyst in all coupling reactions.
The coupling yield increases as temperature increases from 50 to
90 °C (Table 3, entries 3, 6 and 7). However, the yield decreases
when the temperature increases to 110 °C (Table 3, entry 8). Also,
the model reaction was carried out in various solvents: polyethyl-
ene glycol 400 (PEG-400), ethanol (EtOH), dimethylsulfoxide
(DMSO) and dimethylformamide (DMF) (Table 3, entries 3, 9–11).
The results show that PEG-400 is the most desirable solvent. Finally,
we examined the effects of bases on the outcome of the Stille cross-
coupling reaction in PEG-400. Organic and inorganic bases, K2CO3,
NaOAc, KHCO3 and Et3N, were investigated (Table 3, entries 3, 12–
14). K2CO3 is the best base for the reaction in terms of product yield.
The optimized conditions are: Ph3SnCl (0.5 mmol), iodobenzene
(0.5 mmol), catalyst (3 mg), K2CO3 (1.50 mmol) and PEG-400 as sol-
vent at 90 °C (Table 3, entry 3).
After optimizing the reaction conditions, the C&bond;C coupling
reactions of various substituted aryl halides with Ph3SnCl were car-
ried out (Table 4). As evident from Table 4, aryl iodides, bromides
and chlorides with electron-donating and electron-withdrawing
groups react efficiently with Ph3SnCl. Coupling reactions of Ph3SnCl
with aryl iodides and bromides produce the corresponding prod-
ucts in excellent yields and suitable times. The coupling reactions
of aryl chlorides with Ph3SnCl need longer reaction time than those
of aryl iodides and bromides, which gives us the desired product in
moderate yield.
The palladium catalyst [PdBr2(dppe)] can also be applied in the
Suzuki reaction which is one of the most powerful methods for
the production of asymmetric biaryls. As evident from Table 5, var-
ious aryl halides containing both electron-donating and electron-
withdrawing groups react with phenylboronic acid to give the
Table 4. Reaction of structurally different aryl halides with Ph3SnCl in presence of catalysta
Entry
Aryl halide
Iodobenzene
Product
Biphenyl
Time (min)
Yield (%)b
M.p. (°C)
69[30]
45–46[30]
86–88[30]
69[30]
45–46[30]
86–88[30]
111–113[30]
85–87[31]
76–77[30]
69[31]
1
30
45
96
92
86
93
90
84
87
84
88
85
81
78
2
4-Iodotoluene
4-Phenyltoluene
4-Methoxybiphenyl
Biphenyl
3
4-Iodoanisole
80
4
Bromobenzene
45
5
4-Bromotoluene
4-Phenyltoluene
4-Methoxybiphenyl
4-Nitrobiphenyl
4-Cyanobiphenyl
4-Chlorobiphenyl
Biphenyl
50
6
4-Bromoanisole
90
7
4-Bromonitrobenzene
4-Bromobenzonitrile
4-Bromochlorobenzene
Chlorobenzene
95
8
105
45
9
10
11
12
65
4-Chloronitrobenzene
4-Chlorobenzonitrile
4-Nitrobiphenyl
4-Cyanobiphenyl
125
135
111–113[31]
85–87[31]
aReaction conditions: aryl halide (1 mmol), Ph3SnCl (0.5 mmol), K2CO3 (1.5 mmol), PEG (1 ml), catalyst (0.003 g).
bIsolated yield.
Table 5. Coupling of aryl halides with phenylboronic acid in presence of catalytic amount of [PdBr2(dppe)]a
Entry
Aryl halide
Iodobenzene
Product
Biphenyl
Time (min)
Yield (%)b
M.p. (°C)
1
25
40
97
92
85
92
89
83
82
83
87
90
80
76
69[30]
2
4-Iodotoluene
4-Phenyltoluene
4-Methoxybiphenyl
Biphenyl
45–46[30]
86–88[30]
69[30]
3
4-Iodoanisole
75
4
Bromobenzene
40
5
4-Bromotoluene
4-Phenyltoluene
4-Methoxybiphenyl
4-Nitrobiphenyl
4-Cyanobiphenyl
4-Chlorobiphenyl
Biphenyl
45
45–46[30]
86–88[30]
111–113[30]
85–87[23]
76–77[30]
69[23]
6
4-Bromoanisole
80
7
4-Bromonitrobenzene
4-Bromobenzonitrile
4-Bromochlorobenzene
Chlorobenzene
90
8
95
9
55
10
11
12
55
4-Chloronitrobenzene
4-Chlorobenzonitrile
4-Nitrobiphenyl
4-Cyanobiphenyl
115
120
111–113[23]
85–87[23]
aReaction conditions: aryl halide (1 mmol), phenylboronic acid (1 mmol), K2CO3 (1.5 mmol), PEG (1 ml) and catalyst (0.003 g).
bIsolated yield.
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Synthesis of [PdBr2(dppe)] and its application in C C bond formation
Table 6. Comparison of results for [PdBr2(dppe)] with those for other catalysts for the coupling of iodobenzene with phenylboronic acid
Entry
Catalyst
Conditions
Time (min)
Yield (%)a
Ref.
ss
2
3
4
5
6
[PdBr2(dppe)]
PEG, K2CO3, 90 °C
DMF, Cs2CO3, 130 °C
H2O, KOH, 100 °C
25
120
720
480
720
180
97
95
95
95
88
97
This work
[32]
PdCl2
Pd NPs
[33]
[34]
[35]
[36]
Pd-MPTAT-1
NaOH, DMF–H2O (1:5), 85 °C
THF, Cs2CO3, 80 °C
NHC-Pd(II) complex
N,N′-bis(2-pyridinecarboxamide)-1,2-benzene
palladium complex
CA/Pd(0)
H2O, K2CO3, 100 °C
[37]
[38]
[39]
[40]
7
H2O, K2CO3, 100 °C
EtOH–H2O, K2CO3, 80 °C
120
1440
240
94
88
91
94
8
Pd/Au NPs
9
PANI–Pd
K2CO3, 1,4-dioxane–H2O (1:1), 95 °C
K2PO4, EtOH–H2O, 90 °C
10
PVP–Pd NPs
120
aIsolated yield.
corresponding biaryls. The Suzuki reaction was performed under
the optimized reaction conditions determined for Stille cross-
coupling reactions. Moreover, the coupling of aryl iodides and aryl
bromides with phenylboronic acid proceeds at 90 °C and the corre-
sponding products are obtained in high yields, similar to Stille reac-
tions. We also examined the reaction with several substituted aryl
chlorides and phenylboronic acid under the optimized reaction
crystallography. The complex [PdBr2(dppe)] was employed as an ef-
ficient catalyst for both Stille and Suzuki cross-coupling reactions.
The present system shows attractive advantages such as the use
of effective and inexpensive catalyst, convenient one-pot opera-
tion, short reaction time, good to excellent yields of products and
the use of PEG as a green reaction medium that is considered to
be a relatively environmentally benign solvent. High activity was
observed for the catalyst and its reusability was tested in five con-
secutive cycles.
conditions.
A diverse range of aryl chlorides react with
phenylboronic acid to give the desired products in moderate to
good yields.
Acknowledgement
Reusability of Catalyst
This work was supported by the research facilities of Ilam University,
Ilam, Iran.
One of the advantages of catalysts which make them commercially
significant is their reusability. We have found that the catalyst could
be rapidly recovered and demonstrated excellent recyclability. To
investigate this issue, the recyclability of the catalyst was examined
for the reaction of iodobenzene with phenylboronic acid under the
optimal conditions. After the completion of the reaction, the reac-
tion mixture was cooled to room temperature. Then, to separate
the catalyst, the mixture was filtered off. Finally, the catalyst was
dried at 100 °C and was directly used for the next run. As shown
in Fig. 1, the catalyst can be recycled for up to five consecutive runs
without any significant loss of its catalytic activity.
References
[1] M. Albrecht, G. V. Koten, Angew. Chem. Int. Ed. 2001, 40, 3750.
[2] J. Dupont, M. Pfeffer, J. Spencer, Eur. J. Inorg. Chem. 1917, 2001.
[3] G. Dyker, Angew. Chem. Int. Ed. 1999, 38, 1698.
[4] M. E. van der Boom, D. Milstein, Chem. Rev. 2003, 103, 1759.
[5] J. T. Singleton, Tetrahedron 2003, 59, 1837.
[6] T. H. Riermeier, A. Zapf, M. Beller, Top. Catal. 1997, 4, 301.
[7] A. F. Littke, G. C. Fu, Angew. Chem. Int. Ed. 2002, 41, 4176.
[8] P. Schwab, M. B. France, J. W. Ziller, R. H. Grubbs, Angew. Chem. Int. Ed.
1995, 34, 2039.
Comparison of Catalyst
[9] P. McMorn, G. J. Hutchings, Chem. Soc. Rev. 2004, 33, 108.
[10] Y. S. Fu, S. J. Yu, Angew. Chem. Int. Ed. 2001, 40, 437.
[11] R. Martin, S. L. Buchwald, Acc. Chem. Res. 2008, 41, 1461.
[12] M. Jin, J. N. Park, J. K. Shon, J. H. Kim, Z. Li, Y. K. Park, J. M. Kim, Catal.
Today 2012, 185, 183.
[13] P. Das, W. Linert, Coord. Chem. Rev. 2016, 311, 1.
[14] R. B. Bedford, M. E. Limmert, J. Org. Chem. 2003, 68, 8669.
[15] R. B. Bedford, M. Betham, J. P. H. Charmant, A. L. Weeks, Tetrahedron
2008, 64, 6038.
[16] N. T. S. Phan, M. V. D. Sluys, C. W. Jones, Adv. Synth. Catal. 2006, 348,
609.
[17] K. K. Lo, C. Chung, T. K. Lee, L. Lui, K. H. Tang, N. Zhu, Inorg. Chem. 2003,
42, 6886.
The results were compared in order to examine the efficiency of the
coupling of iodobenzene and phenylboronic acid (Table 6) with
some reported C&bond;C coupling reactions in the presence of
other catalysts. Table 6 shows that the catalyst under investigation
leads to shorter reaction time and higher reaction yield than the
previously reported catalysts. In particular, the reaction catalysed
by [PdBr2(dppe)] can be performed efficiently without using toxic
organic solvent, and this new catalyst is also an appropriate catalyst
with higher stability and easier separation than the previously re-
ported catalysts.
[18] J. Buey, P. Espinet, J. Organometal. Chem. 1996, 507, 137.
[19] G. Wittig, Angew. Chem. 1980, 92, 671.
[20] I. Maluenda, O. Navarro, Molecules 2015, 20, 7528.
[21] M. A. Zolfigol, V. Khakyzadeh, A. R. Moosavi-Zare, A. Rostami, A. Zare,
N. Iranpoor, M. H. Beyzavie, R. Luque, Green Chem. 2013, 15, 2132.
[22] A. Rostami, A. Rostami, A. Ghaderi, J. Org. Chem. 2015, 80, 8694.
[23] A. Ghorbani-Choghamarani, F. Nikpour, F. Ghorbani, F. Havasi, RSC Adv.
2015, 5, 33212.
Conclusions
In summary, the method presented represents an attractive and
easy procedure for the synthesis of [PdBr2(dppe)] by direct reaction
of 1,2-bis(diphenylphosphino)ethane with palladium(II) bromide,
the structure of which was characterized using X-ray
[24] A. Rostami, A. Rostami, N. Iranpoor, M. A. Zolfigol, Tetrahedron Lett.
2016, 57, 192.
Appl. Organometal. Chem. (2016)
Copyright © 2016 John Wiley & Sons, Ltd.
wileyonlinelibrary.com/journal/aoc

A. Naghipour et al.
[25] A. X. Yi, J. Han, J. S. Lee, K. M. Y. Leung, Environ. Toxicol. 2016, 311, 13.
[26] J. A. Navio, F. J. Marchena, C. Cerrillos, F. Pablos, J. Photochem. Photobiol.
A 1993, 71, 97.
[36] Q. Du, W. Zhang, H. Ma, J. Zheng, B. Zhou, Y. Li, Tetrahedron 2012, 68,
3577.
[37] V. W. Faria, D. G. M. Oliveira, M. H. S. Kurz, F. F. Goncalves,
[27] Stoe & Cie, X-AREA: Program for the acquisition and analysis of data,
Version 1.30, Stoe & Cie GmbH, Darmstadt, Germany, 2005.
[28] J. C. Slater, J. Chem. Phys. 1964, 413, 199.
C. W. Scheeren, G. R. Rosa, RSC Adv. 2014, 4, 13446.
[38] M. Nasrollahzadeh, A. Azarian, M. Maham, A. Ehsani, J. Ind. Eng. Chem.
2015, 21, 746.
[29] G. M. Sheldrick, Acta Crystallogr. A 2008, 64, 112.
[30] Stoe & Cie, X-STEP32: Crystallographic package, Version 1.07b, Stoe &
Cie GmbH, Darmstadt, Germany, 2000.
[39] H. A. Patel, A. L. Patel, A. V. Bedekar, Appl. Organometal. Chem. 2015,
29, 1.
[40] P. M. Uberman, L. A. Perez, S. E. Martın, G. I. Lacconi, RSC Adv. 2014, 4,
[31] A. Naghipour, A. Ghorbani-Choghamarani, F. Heidarizadi, B. Notash,
12330.
Polyhedron 2016, 105, 18.
[32] S. J. Sabounchei, A. Hashemi, Inorg. Chem. Commun. 2014, 47, 123.
[33] M. Nasrollahzadeh, S. M. Sajadi, M. Maham, J. Mol. Catal. A 2015, 396,
297.
Supporting information
[34] A. Modak, J. Mondal, M. Sasidharan, A. Bhaumik, Green Chem. 2011, 13,
1317.
Additional supporting information may be found in the online ver-
[35] T. Chen, J. Gao, M. Shi, Tetrahedron 2006, 62, 6289.
sion of this article at the publisher’s web-site.
wileyonlinelibrary.com/journal/aoc
Copyright © 2016 John Wiley & Sons, Ltd.
Appl. Organometal. Chem. (2016)