Thiazole-based non-symmetric NNC-palladium pincer complexes as catalytic precursors for the Suzuki-Miyaura C-C coupling

Article abstract of DOI:10.1039/c9nj02977j

We report an efficient synthesis of new non-symmetric pincer palladacycles 2a-i, containing a [NNC]-tridentate ligand formed by a hydrazone and a thiazolyl moiety as sources of N-donor atoms. These catalytic precursors were tested in the Suzuki-Miyaura cross coupling reaction using a variety of aryl boronic acids with aryl bromides or chlorides using water as solvent. Complex 2a displays the best catalytic performance under aerobic conditions, affording the coupling products in good to high yields. In all cases, the cross-coupling reaction was conducted under IR irradiation, allowing a decrease in the reaction time.

Full text of DOI:10.1039/c9nj02977j

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Thiazole-based non-symmetric NNC-Palladium pincer complexes
as catalytic precursors for the Suzuki–Miyaura C-C coupling
Received 00th January 20xx,
Accepted 00th January 20xx
a
a
b
Martín Camacho-Espinoza, Alberto Reyes-Deloso, R. Alfredo Toscano, J. Guillermo Penieres-
a
b
c,
a,
Carrillo, José G. López-Cortés, M. Carmen Ortega-Alfaro * and Fernando Ortega-Jiménez *
DOI: 10.1039/x0xx00000x
We report an efficient synthesis of new non-symmetric pincer palladacycle 2a-i, containing a [NNC]-tridentate ligand
formed by a hydrazone and a thiazolyl moiety as source of N-donor atoms. These catalytic precursors were tested in the
Suzuki–Miyaura cross coupling reaction using a variety of aryl boronic acids with aryl bromides or chlorides using water as
solvent. Complex 2a displays the best catalytic performace under aerobic conditions, affording the coupling products in
good to high yields. In all cases, the cross-coupling reaction was conducted under IR irradiation, allowing to decrease the
reaction times.
3
-1
4
.9 X 10 h . However, when the structural architecture of the
1
4a
Introduction
tridentate ligand is modified like in hydrazones VII
VIII, the catalytic performance in Heck reaction is improved,
reaching TOFs of 7.8 X 10 (h ) and 3.7 x 10 (h ), respectively.
Although, the complex VIII was formed in situ, its catalytic
performance resulted attractive for this kind of C-C coupling
reactions.
and
1
4b
Palladium pincer complexes are a subclass of cyclic complexes
3
-1
3
-1
1
,2
incorporating two fused palladacycles.
This kind of
3
complexes exhibits versatile applications, which arises from
their stability and unique reactivity as result of the tridentate
coordination mode of the ligands and the presence of a metal-
On the other hand, the Suzuki-Miyaura cross-coupling reaction
is a versatile tool to obtain a plethora of biaryl compounds, in
4
carbon bond. Most of palladium pincer complexes are
symmetric,5 and only a limited number of non-symmetric
complexes have been reported. They are often synthesized by
1
5
very soft conditions and great selectivity. These important
structural units are found in diverse pharmaceuticals and
6
more challenging routes than their symmetric analogues.
1
6
natural products. In this context, some non-symmetric pincer
complexes containing a heterocyclic moiety have also been
used as efficient pre-catalysts for the Suzuki-Miyaura cross-
However, the catalytic efficiencies of non-symmetric pincer-
palladacycles for some chemical processes are better than
those of symmetric ones. Thus, non-symmetric pincer ligands
could be envisaged as important scaffolds for designing new
and efficient catalysts for various organic transformations
including C–C coupling.
7
8
-12
coupling.
1
7
Likewise, infrared irradiation (IR) is an energy source scarcely
used as non-conventional heating in comparison to
1
8
microwaves. As a research program focused on the use of IR
in C-C coupling reactions, recently we have explored the use of
Some examples of non-symmetric pincer palladacycles with
interesting catalytic applications in C-C cross coupling
reactions contain a central phenyl group as rigid planar
backbone, including different heterocyclic moieties as part of
1
4,19
20
IR to assist the Mizoroki-Heck,
and Suzuki-Miyaura cross-
coupling reaction with very good results.
8
9
the ligand. Thus, we can find pyrazoles I, oxazolines II, azoles
1
0
11
12
III, benzothiazoles IV, benzaldimines V, benzimidazoles
N
N
O
S
1
3
N
Pd
Cl
N
Ph2P
S
VI, among others (Fig. 1). This kind of complexes exhibits a
good catalytic performance, showing TOF values ranging 0.4 to
Pd
Cl
N
R
X
O
N
Pd
Cl
N
Pd
Cl
IV
N
R'
R
HN PPh2
R = CH3 o H, R' = i-Pr
II
IIIa, X = O
IIIb, X = S
I
nBu
N
a. Departamento de Ciencias Químicas, Facultad de Estudios Superiores Cuautitlán-
UNAM, Campo 1, Avenida 1ro. de Mayo s/n, Cuautitlán Izcalli, C.P. 54740, Estado
de México, México. E-mail: fdo.ortega@unam.mx
. Instituto de Química UNAM, Circuito Exterior, Ciudad Universitaria, Coyoacán
C.P. 04360, Cuidad de México, México
O
Ph2P
S
N
N
N
S
(
)n
R2P
Pd
Cl
N
N
Pd
N
Pd
N
Pd
N
b.
Cl
V
Cl
OAc
formed in situ
VI
VIII
VII
c.
Instituto de Ciencias Nucleares, UNAM, Circuito Exterior, Ciudad Universitaria,
Coyoacán C.P. 04360, Ciudad de México, México. E-mail:
Fig. 1 Selected pincer complexes as catalytic precursors in C–C cross-coupling reactions.
carmen.ortega@nucleares.unam.mx
Electronic Supplementary Information (ESI) available: Experimental procedures
and characterization data of all compounds. CCDC-1863612 (1g). For
crystallographic data in CIF format See DOI: 10.1039/x0xx00000x
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On continuing with our interest in the synthesis and catalytic
applications of non-symmetric pincer complexes, we envisaged
the synthesis of new non-symmetric [NNC]-tridentate ligands
combining a hydrazone functionality with a thiazolyl moiety.
This five-membered heterocyclic fragment can behave as
strong sigma N-donor ligand. We consider that this structural
combination could provide a best stability to the complex
View Article Online
DOI: 10.1039/C9NJ02977J
1
4b
formed in comparison to its benzothiazole analogue,
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allowing to have full evidences about the formation of non-
symmetric pincer complexes, as well as a better tuning of its
catalytic properties. We also describe the catalytic applications
of these complexes in Suzuki-Miyaura cross-coupling reaction
in water promoted by IR irradiation.
Fig. 2 ORTEP representation of ligand 1g. Ellipsoids are shown at 30% probability level.
Selected bond distances [Å]: N1-C4 1.306(2), C4-S1 1.718(2), C4-C5 1.446(3), C5-N2
1.280(2), N2-N3 1.355(2), N3-C12 1.441(2), N3-C6 1.409(2). Selected bond angles [°]:
N1-C4-S1 114.6(1), N1-C4-C5 124.0(2), C4-C5-N2 117.6(2), C5-N2-N3 120.6(2), N2-N3-
C12 121.4(1), N2-N3-C6 116.6(1).
Results and discussion
The arylhydrazones containing a 2-thiazolyl moiety 1a-i were
With these ligands, we conducted the synthesis of the
corresponding pincer complexes. Initially, this reaction was
synthesized by
a condensation reaction between the
corresponding arylhydrazine and the 2-thiazolyl carbonyl
compound under IR irradiation (Table 1). After purification, the
tridentate ligands 1a-i were obtained in good yields. When the
same reaction was conducted at reflux conditions under
thermal heating, we obtained similar yields, but the time
increases between 6-8 h.
carried out at room temperature, using the ligand 1a and PdCl
2
in EtOH. After 72 h of reaction, the ligand was totally
consumed, and two new products were formed. We isolated
the corresponding complex 2a in 10% yield and a more polar
compound by flash chromatography, which was unstable and
non-soluble in organic solvents. This behavior restricted its
spectroscopic characterization. In attempt to increase the yield
of 2a, we conducted this reaction at reflux conditions of
These ligands were fully characterized by conventional
1
13
spectroscopic techniques, H NMR, C NMR, IR and MS. All
spectroscopic data are consistent with the structure of aryl
hydrazones 1a-i. Likewise, the molecular structure of the 1g
was fully confirmed by single crystal X-ray diffraction analysis
(Fig. 2). As we can see, almost the thiazolyl and hydrazone
fragments are coplanar with the phenyl ring formed by the
atoms C6-C11, leading the other phenyl ring in orthogonal
position (Torsion angle: 72.49°). Also, the bond distance for
2
EtOH/H O (1: 2) as binary solvent, under IR irradiation. During
the reaction, the TLC revealed the presence of both products.
After 1.5 h of heating, we only detected the complex 2a by
TLC. Finally, 2a was obtained as orange solid in 90% of yield.
According to the mechanism proposed by Parsall,22 the polar
compound observed could be the dimeric complex (A) formed
as possible intermediate in the synthesis of 2a. Nevertheless,
the ligand 1a could also act as a bidentate [N,N]-ligand, giving
2
1
N2-N3 agrees with the literature.
a five members chelate-complex (B) similar to those observed
Table 1. Synthesis of tridentate ligands 1a-i.
23,24
in other reports.
In every case, when the temperature
increases, this species evolves to the more stable pincer
complex 2a (Scheme 1). Taking into account these results,
direct cyclopalladation reactions were carried out with each
R
R
g
a
h
N
f
N
MeOH
b
e
c
N
O
+
H2N
S
N
S
N
d
IR Reflux
ligand, using 1 equiv. of PdCl under IR irradiation in a mixture
2
R'
R''
R'
R''
1a-i
2
Cl
Pd
Ligand
R
R’
Me
Me
Me
Me
Me
Me
H
R’’
Time (h)
1.5
1.5
2.5
3.5
1.5
1.5
2
Yield (%)
76
N
N
1
1
a
b
Me
Me
Me
H
Ph
Me
Bz
Ph
Me
Bz
Ph
Me
Bz
Ph
84
70
72
68
80
83
97
80
N
S
Cl
Pd
N
PdCl2
N
1
c
N
EtOH / H2
O
EtOH / H2
(1:2)
O
S
N
Ph
(A)
(1:2)
N
1
1
d
e
N
R.T.
IR Reflux
Ph
Cl
H
H
S
N
Pd Cl
N
1a
2a
1
f
S
N
Ph
1
g
Me
Me
Me
(B)
1
h
H
H
2
2
1i
Scheme 1. Synthesis of pincer complex 2a through the possible intermediate A or B
2
| J. Name., 2012, 00, 1-3
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Table 2. Synthesis of pincer complexes 2a-i.
complexes 2a-i and agree with their molecular struc res. On
View A cle Online
turti
DOI: 10.1039/C9NJ02977J
the other hand, the FT-IR data show a shifting towards lower
wavenumbers for the imine ν(C=N) band compared to that of
free ligand, as clear indicative of the nitrogen coordination to
the palladium atom.
R
R
a
Cl
Pd
N
g
j
f
N
EtOH/H2O (1:2)
IR Reflux
N
h
i
+
PdCl2
b
e
N
c
d
S
N
S
N
R'
a-i
R''
R'
2a-i
R''
The success of the cyclopalladation reaction was also
1
1
confirmed by NMR spectroscopy. For instance, in the H-NMR
spectrum of 2a, we observed two sets of aromatic protons
assigned to two aromatic systems with a different substitution
pattern. The first set of signals corresponds to the typical
multiplicity observed for an 1,2-disubstituted aromatic ring
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Complex
R
R’
Me
Me
Me
Me
Me
Me
H
R’’
Ph
Me
Bz
Ph
Me
Bz
Ph
Me
Bz
Time (h)
1.5
0.5
2
Yield (%)
90
2a
2b
2c
Me
Me
Me
H
94
52
97
64
76
90
88
77
1
4,22
2
d
e
0.5
0.5
0.5
0.5
0.2
2
consistent with the ortho-palladation of the phenyl group.
2
H
H
Likewise, we detected both the absence of the signal
attributable to the H-f proton of these ligands and the high-
field shift of the doublet assigned to H-g proton (from 7.44
ppm in 1a to 6.04 ppm in 2a  = 1.4) in the complex. These
modifications in both the chemical shift and multiplicity are
clearly evident in the case of complexes 2b, 2e and 2h. The
second set of signals assigned to the substituents included on
the amino group in these pincer complexes remains without
significant changes in comparison with those of ligands. A
similar behavior is observed across the series 2b-i.
The C{ H} NMR analyses displayed the expected peaks for
the pincer complexes 2a-i. For instance, the signal for the
imine carbon (C-d) in 2a-i is shifted at downfield respect to the
free ligand. A similar behavior is observed for C-a, which
indicates
2
f
2
g
Me
Me
Me
2
h
H
H
2
i
2
of EtOH/H O (1:2) (Table 2). After purification by flash
chromatography, the complexes 2a-i were successfully isolated
as air- and moisture-stable orange solids, in good yields. The
spectroscopically data obtained for these compounds
corroborate the formation of these new palladium pincer
complexes. For instance, elemental analyses of 2a-i are
consistent with the proposed molecular structure (see
experimental section). The results obtained by mass
13
1
+
spectrometry (FAB -MS), show the molecular ions for the
Table 3. Optimization of conditions for the Suzuki-Miyaura cross-coupling reaction using the complexes 2a-i. a
Br
B(OH)2
2(a-i)
+
K3PO4 / TBAB / H2O
IR, reflux
MeO
MeO
3a
4
5a
Entry
Complex
[2]
time
(min)
Yield
(%)d
traces
45
90
85
65
80
60
70
70
70
85
80
70
88
90
89
TONh
TOF
b
c
-1
i
(% mol)
0.01
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
(h )
e
1
2
2a
2a
2a
2a
2a
2b
2c
2d
2e
2f
2g
2h
2i
2a
2a
2a
50
60
50
-
-
e
2250
4500
4250
3250
4000
3000
3500
3500
3500
4250
4000
3500
4400
4500
4450
2250
5400
1416
33
3
f
4
5
180
5760
50
g
6
7
8
9
4800
3000
3500
3500
2333
4250
4000
3000
5280
5400
5340
60
60
60
90
60
60
70
50
1
0
11
12
13
1
4j
5k
6l
1
1
50
50
a
(1 mmol), TBAB (1 mmol) at 96 °C. b A freshly solution of
3 4
Reaction conditions: 4-Bromoanisole 3a (0.5 mmol), phenylboronic acid 4 (0.6 mmol), water (3 mL), K PO
-3
c
d
complex 2 in DMA 5x10 M is used. Based on total consumption of 4-bromoanisole determined by TLC. Isolated yields after purification by column chromatography.
e
f
g
h
Reaction conducted in absence of TBAB. Reaction conducted under thermal heating, T = 96 °C. Reaction conducted at room temperature. TON = ratio of moles of
i
j
k
product formed to moles of catalyst used. TOF = TON/t. Reaction conducted in the presence of a Hg(0) drop. Reaction conducted in a scale of 0.025 mmol of 3a,
l
phenylboronic acid 4 (0.03 mol), 15 mL of H
0.03 mol), 15 mL of H O, K PO
2 3
O, K PO
4
(0.025 mol), TBAB (0.05 mol) at 96 °C. Reaction conducted in a scale of 0.025 mol of 3a, phenylboronic acid 4
(
2
3
4
(0.025 mol), TBAB (0.05 mol) at 96 °C, in the presence of a Hg(0) drop.
This journal is © The Royal Society of Chemistry 20xx
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the formation of N-Pd-N chelate, between the N atoms of similar activity with TONs of around 4 × 10 , but complex 2a is
thiazole ring and imine group. In addition, the signal of more efficient as revealed the TOF values.
methine HC-f in all ligands disappears after the ortho-
metallation, and now appears as a quaternary carbon shifted As we can see, the presence of DMA as co-solvent, water as
at higher frequencies, revealing the formation of the ortho- reactional media and TBAB as additive would suggest that the
palladacycle. The chemical shifts of the other carbon atoms catalyst is more heterogenous than homogeneous. Thus, to
(e.g., C-g, C-h and C-i) are also indicative of the pincer complex dismiss the formation of Pd(0) nanoparticles, we conducted
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formation. This spectroscopic behavior agrees with others three additional experiments. First, we carried out the mercury
cyclopalladated complexes reported in literature.
The stability to air and moisture conditions of these palladium a similar performance of the catalysts 2a (Table 3, entry 14).
pincer-type complexes, prompted us to conduct the catalytic Likewise, to discard the effect of DMA as co-solvent in the
experiments in open vessel, using analytical grade solvents, reaction, the coupling between bromoanisole and
implying an additional advantage. In addition, as we recently phenylboronic acid, was conducted under the optimum
reported,1
source to promote this coupling reaction.
We begin the catalytic studies using the coupling between 4- solid. After 50 minutes of infrared irradiation, at 96 °C, we
bromoanisole and the phenylboronic acid as a model reaction. obtained a similar yield, and no visible black Pd material was
We chose the complex 2a as a precatalyst (0.01% mol) at observed. Additionally, this experiment was performed in the
water reflux, however no coupling product was obtained presence of a mercury drop (Table 3, entry 16), obtaining a
1
4,25
drop experiment under the best reaction conditions, obtaining
4, 19, 20
we decided to use IR as alternative energy reaction conditions, on a scale of 25 mmol (4.67 g) (Table 3
entry 15) and adding directly the palladium complex 2a as
(
Table 3, entry 1). When we increased to 0.02 % mol of 2a, the similar yield of the coupling product. These results suggest that
coupling product was obtained in 45 % yield, after 60 minutes neither palladium nanoparticles nor soluble Pd(0) species are
Table 3, entry 2). We observed that the mixture reaction was responsible for the observed catalytic activity and in
no completely homogenous, we thus decided to use TBAB as consequence heterogeneous catalysis could not be
(
a
2
7
additive, finding that this compound favors the reaction, involved.
yielding the coupling product in 90 %, after 50 minutes of Finally, to know if the pincer complexes 2 could be pre-formed
reaction time (Table 3, entry 3). in situ and then used as catalytic precursors in the Suzuki-
To know the role of infrared irradiation for promoting this Miyaura coupling reaction, we carried out the coupling
coupling reaction, we conducted two additional experiments, between bromoanisole and phenylboronic acid under the
the first one was performed at reflux conditions under thermal optimal reaction conditions. For comparison purposes, we
heating (Table 3, entry 4), obtaining the coupling product in 85 tested the ligands 1a, 1d, 1g and VIII (Fig. 1) in the presence of
%
2
yield after 3 h of reaction time. In a second experiment, we PdCl (Table 4). In all cases, the coupled product was obtained
have carried out the reaction at room temperature (Table 3, in moderated yields, in longer time (Table 4, entries 1-4).
entry 5) achieving 65 % yield of 5a, being necessary to increase Comparing these results with those obtained with its
the reaction time until 96 h. These results revealed that the benzothiazole analogue, we observe that in this case, the
use of infrared as energy source favors the Suzuki-Miyaura palladacycle formation is crucial to enhance the catalytic
coupling reaction to obtain the corresponding products in an performance of these catalytic precursors, which is favored
efficient manner. This effect can be rationalized if we consider when ethanol is included in the reactional media (Table 2).
that IR irradiation produces at molecular level
nonequilibrium distribution of vibration states (bending and
torsion) that selectively influences the course of a chemical
reaction.26 Thus, the energy provided by the mid-infrared
source would provoke that the dissociative mechanism was
favored, increasing the reaction rate, which forces that the
coupling reaction proceeds quickly. Evidences of this effect has
been obtained by K. Heine et al using femtosecond IR-pump
IR-probe experiments, to promote the acceleration of
urethane and polyurethane formation due to vibrational
1
4b
a
Table 4 Suzuki-Miyaura cross-coupling reaction using the ligands 1 and PdCl
2
.a
Br
B(OH)2
Catalyst
+
K3PO4 / TBAB / H2O
IR, reflux
MeO
MeO
3a
4
5a
Entry
Catalyst
time
Yield
(%)c
55
50
50
TONd
TOF
(h )
b
-1 e
(min)
120
140
120
150
360
1
2
3
4
5
1a/PdCl
1d/PdCl2
2
3250
3000
3000
2800
1750
1625
1285
1500
1120
291
2
6a
excitation of the reactants.
1g/PdCl
VIII/PdCl
PdCl
2
A direct consequence of this effect is observed in the
dramatical decreasing in the reaction time evidenced in
synthesis of ligands 1a-i, complexes 2a-i and other several
chemical transformations where mid-IR irradiation has been
used as a source of energy.
We have also tested the performance of pincer complexes 2b-
i, under the same reaction conditions as 2a (Table 3, entries 6-
2
56
30
2
a
Reaction conditions: 4-Bromoanisole 3a (0.5 mmol), phenylboronic acid 4 (0.6 mmol),
K
3
PO (1 mmol), TBAB (1 mmol), H
4
2
O (3 mL), Catalyst 0.02 % mol, T = 96 °C. b Based on
1
7
total consumption of 4-bromoanisole determined by TLC. c Isolated yields after
purification by column chromatography. d TON = ratio of moles of product formed to
moles of catalyst used. e TOF = TON/t.
1
3). Comparing the activity and efficiency, we observed a
4
| J. Name., 2012, 00, 1-3
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New Journal of Chemistry
Journal Name
ARTICLE
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
When, the same reaction was performed in the absence of After analyzing the results obtained, we concludVieewdArtthicaletOntlhinee
ligand, we only reached 30% of yield, even when the time best conditions are 0.02% mol of complDeOxI:21a0,.105309/mC9inNuJ0te29s7o7Jf
increased until 3 h (Table 4, entry 5). Likewise, it is important reaction time, H O as a solvent, K PO as base and TBAB as
2 3 4
to notice that under these conditions, the ligands do not additive, under IR irradiation. With the optimized reaction
experiment decomposition due to their presumable hydrolysis conditions in hand, we then examined the scope of the Suzuki-
by the basic conditions.
Miyaura coupling reaction using both different aryl bromides
and phenylboronic acids (Table 5).
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
Table 5. Scope of Suzuki-Miyaura cross-coupling of aryl bromides and phenyl boronic acids under IR irradiation.a
B(OH)2
0
.02 mol% 2a
Ar
R'
Ar Br
K3PO4 / TBAB / H2O
IR, reflux
R'
3
4
5(a-q)
Entry
Aryl halide (3)
Boronic acid (4)
Biaryl (5)
time (min)b
Yield (%)c
TONd
4500
4500
4600
4250
TOF (h-1)e
5400
1
2
3
4
MeO
Me
Br
B(OH)2
5a
5b
5c
5d
50
60
90
90
92
85
Br
B(OH)2
B(OH)2
B(OH)2
4500
Me
90
3066
Br
Me
240
106
Br
Br
B(OH)2
5
6
5e
5f
120
300
93
85
4650
4250
2325
850
Me
Me
Br
Br
B(OH)2
B(OH)2
B(OH)2
B(OH)2
B(OH)2
B(OH)2
B(OH)2
B(OH)2
7
8
9
5g
5h
5i
180
30
99
95
96
50
60
60
12
92
95
70
95
4950
4750
4800
2500
3000
3000
600
1650
9500
7200
250
O2N
Ac
Br
Br
40
Br
1
1
1
1
1
1
0
1
2
3
4
5
5j
600
300
120
420
90
N
Br
5k
5l
600
N
Br
Br
1500
85
S
5m
5n
5o
5p
5q
S
MeO
MeO
MeO
MeO
Br
Br
Br
Br
Me
MeO
O2N
F3C
B(OH)2
B(OH)2
B(OH)2
B(OH)2
4600
4750
3500
4750
3066
2375
1166
120
180
50
16
1
7
5480
a
b
Reaction condition: Aryl halide 3 (0.5 mmol), phenylboronic acid 4 (0.6 mmol), H
2
O (3 mL), K
3
PO
4
(1 mmol), [2a] = 0.02 % mol, TBAB (1 mmol), T = 96 °C. Time based
c
d
on total consumption of aryl halide determined by TLC. Yields Isolated after extraction with hexane and SiO
product formed to moles of catalyst used. TOF = TON/t.
2
column chromatography. TON = ratio of moles of
e
This journal is © The Royal Society of Chemistry 20xx
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ARTICLE
Journal Name
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
View Article Online
DOI: 10.1039/C9NJ02977J
The results indicate that aryl bromides containing electron- bromides. Under similar conditions, we conduct a cross-
donating and electron-withdrawing groups with phenylboronic coupling reaction between 4-nitrochlorobenzene and the
acid proceeded satisfactorily, and the corresponding coupling phenylboronic acid, using 0.02 % mol of 2a. We obtained 54 %
products were obtained in high to excellent yields (Table 5, yield in
entries 1-9).
7 h (Table 6, entry 1). After increasing the
concentration of 2a to 0.1 % mol we obtain an excellent yield
of the coupled product 95% in 5 h (Table 6, entries 2).
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
We have also evaluated the steric hindrance of the substituent
on the aryl bromide using as staring materials: 3- We then studied the scope of these substrates using different
bromotoluene, 2-bromotoluene, 1-bromonaphtalene and even phenylboronic acids (Table 6). For activated aryl chlorides, we
the sterically hindered 2-bromo-1,3-dimethylbenzene. In all obtained excellent yields (Table 6, entries 4-6). However, for
cases, the reaction time increases but the corresponding deactivated aryl chlorides such as 4-chlorotoluene or 4-
biaryls are obtained in excellent yields (Table 5, entries 3-6).
Likewise, heteroaryl bromides such as 2-bromopyridine, 3- and 8). In this context, their structurally similar palladium
bromopyridine, 2-bromothiophene and 3-bromothiophene, complex [VIII/Pd(OAc) ] resulted non active, even when
can be coupled efficiently with phenylboronic acid, giving the activated aryl chlorides were used as subtrates.14b These
corresponding biaryls in good yields (Table 5, entries 10-13), results evidence the best performance of the catalytic system
although these substrates need a longer reaction time. formed by complex 2a.
chloroanisole, poor yields were obtained. (Table 6, entries 7
2
Furthermore, a diverse choice of aryl boronic acids bearing
methyl, methoxy, nitro and trifluoromethyl substituents were On the other hand, comparing the reported activity of some
successfully coupled using this cross-coupling reaction, leading non-symmetric pincer palladacycles with the complex 2a, using
the desired products in high yields from 70–95% (Table 5, aryl bromides as precursors in the Suzuki-Miyaura coupling
entries 14-17).
reaction (Table 7), we can see that our catalytic system
produces higher yields of the coupled product in short reaction
These results prompt us to explore more challenged substrates times.
like aryl chlorides since they are more readily available, less
expensive but at the same time less reactive than aryl
Table 6. Scope of Suzuki-Miyaura cross-coupling of aryl chlorides and phenyl boronic acids under IR irradiation.a
R'
Cl
B(OH)2
2a
+
K3PO4 / TBAB / H2O
IR, reflux
R''
R'
R''
6
4
5
Entry
[2a] (% mol)
Aryl chloride (6)
Boronic acid (4)
Biaryl (5)
time (h)b
Yield (%)c
TONd
TOF (h-1)e
1
2
0.02
0.1
O2N
O2N
Cl
Cl
B(OH)2
B(OH)2
5h
5h
7
54
95
2700
950
385
190
5.5
3
4
5
6
7
8
0.1
0.1
0.1
0.1
0.1
0.1
O2N
O2N
O2N
O2N
Me
Cl
Cl
Cl
Cl
Cl
Cl
MeO
Me
B(OH)2
B(OH)2
5p
5r
6.5
7
85
95
95
60
10
15
850
950
950
600
100
150
141
135
190
100
16
F3C
O2N
B(OH)2
B(OH)2
B(OH)2
B(OH)2
5s
5t
5
6
5b
5a
6
MeO
6
25
a
b
Reaction condition: Aryl chloride 6 (0.5 mmol), phenylboronic acid 4 (0.6 mmol), H
2
O (3 mL), K
3
PO
4
(1 mmol), TBAB (1 mmol), T = 96 °C. Based on total consumption
column chromatography. TON = ratio of moles of product formed to moles
c
d
of aryl chloride determined by TLC. Isolated yields after extraction with hexane and SiO
of catalyst used. TOF = TON/t.
2
e
6
| J. Name., 2012, 00, 1-3
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New Journal of Chemistry
Journal Name
ARTICLE
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
Table 7. Catalytic performance of different unsymmetrical pincer palladacycles in the Suzuki-Miyaura cross-coupling.
View Article Online
DOI: 10.1039/C9NJ02977J
R'
Br
B(OH)2
+
Pd complex
Conditions
R''
R'
R''
Entry
Pd complex (% mol)
II (0.1)
Conditions
, Dioxane, 110 °C
, Dioxane, 110 °C
PO4, DMF 120 °C
PO4, DMF, 120 °C
Time
Yield
98
97
99
98
TON
TOF
141
129
1960
196
5760
Ref
9
10b
11
12a
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
K
K
2
CO
CO
3
7 h
15 h
5 h
5 h
50 min
990
1940
9800
980
IIIb (0.1)
IV (0.01)
V (0.1)
2a (0.02)
2
3
K
3
K
3
K
3
PO4,
H
2
O, TBAB, 96°C
96
4800
This work
B(OH)3
PO4-3
H2O
B(OH)4-
HPO4-2
+
Ar
Ar
Ar-B(OH)2
N
Pd
Ar
R''
N
Transmetallation
N
R'
R
S
Ar
N
HO
N
Ar Ar
Pd
Reductive
elimination
(H)
Ar
N
R
R''
R'
S
(G)
Br-
Ar
(s)
nBu4NOH
HPO4-2 H2O
PO4-3
N
Pd
N
R''
N
(
E)
R'
R
Ar
R''
Br
S
S
nBu4NBr
+
N
Pd
Ar
N
Oxidative
Addtion
Reductive
elimination
N
R'
R
R''
N
R'
Ar-Br
(F)
S
N
Pd
Ar
N
Ar-Br
R
(
D)
Oxidative
Addtion
Transmetallation
Ar-B(OH)2
R''
R'
R''
N
R'
N
S
R''
N
R'
N
S
S
N
N
N
nBu4NOH*
Pd
H2O
Pd
OH
(C)
N
HO Ar
Br
R
Pd
N
Cl
2
R
R
(I)
Ar-B(OH)2
Transmetallation
nBu4NOH*
H2O
R''
R'
*
vía the reaction
H O
N
N
S
PO4-3
nBu4NBr + -OH
s) = H2O
HPO4-2 + -OH
nBu4NOH
+
2
R''
N
R'
N
Pd
Ar
+
Br-
S
N
Br
Ar
R
Reductive
elimination
(
Pd
Br
(K)
N
(J)
R
Ar Ar
Scheme 2. Plausible catalytic cycles for Suzuki-Miyaura reaction using the pincer complexes 2.
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ARTICLE
Journal Name
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
View Article Online
DOI: 10.1039/C9NJ02977J
+
To date, there is still controversy about the mechanistic The MS-FAB and MS-EI spectra were obtained on a JEOL SX
pathway for Suzuki cross-coupling reactions catalyzed by 102a, the MS-DART spectra were obtained with an AccuTOF
1
,2
palladium pincer complexes. Depending on the structure of JMS-T100LC, the values of the signals are expressed in
the palladium complex and the conditions used, two mass/charge units (m/z), followed by the relative intensity
mechanistic proposal are possible: a Pd(0)/Pd(II) redox cycle with reference to a 100% base peak. Elemental analyses for
with destruction of the palladacycle or a Pd(II)/Pd(IV) cycle carbon, hydrogen and nitrogen atoms were performed on a
maintaining the palladacycle intact and although we feel that Thermo Scientific elemental analyzer, Flash 2000 using
the former is the most probable case, the latter one should not sulfanilamide as standard and a Perkin Elmer elemental
in principle be completely ruled out for the following reasons. analyzer, PE2400 using Cistine as standard.
As observed, all experiments suggested the presence of a
palladium (II) specie as catalytic precursor in this reaction, and
the preformation of complexes 2 was critical to reach their
best catalytic performance. In addition, the reaction media can
favor the formation of nBu
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
Structure determination by X-ray crystallography.
Suitable X-ray-quality crystals of 1g were grown through slow
evaporation of a chloroform/benzene solvent mixture at –5°C.
4 4
NOH from water and nBu NBr in
A single crystal of compound 1g was mounted on a glass fiber
at room temperature. The crystal was then placed on a Bruker
SMART APEX CCD diffractometer equipped with Mo-Kα
radiation; decay was negligible in all cases. Details of
crystallographic data collected on compound 1g are provided
in Table 8. Systematic absences and intensity statistics were
used in space group determinations. The structure was solved
using direct methods. Anisotropic structure refinements
were achieved using full-matrix least- squares techniques on
all non-hydrogen atoms. All hydrogen atoms were placed in
idealized positions, on the basis of hybridization, with isotropic
thermal parameters fixed at 1.2 times the value of the
attached atom. Structure solution and refinement were
basic conditions. This reagent has been used in the synthesis of
2
8
hydroxo-palladium complexes. Thus, the hydroxo-complex C
can follow two plausible routes (Scheme 2). In the first case,
this species can react with the aryl boronic acid via a
transmetallation reaction to give D as Amatore previously
detected with similar hydroxo-palladium complexes. Then, D
undergoes a reductive elimination, provoking the formation of
the Pd(0) species E, which could be responsible of the catalytic
2
9
3
2
activity. This type of species can be stabilized by solvent
coordinated.30
On the other hand, the structural architecture of C let us
visualize it as special pincer complex containing a hemilabile
side arm, which can decoordinate the palladium atom for
assisting the oxidative addition of the aryl bromide producing
I. This species then reacts with the aryl boronic acid leading J.
Finally, a reductive elimination affords the desired biphenyl,
followed by the regeneration of Pd(II) active species C. A
similar Pd(II)/Pd(IV) mechanism has been postulated using
related pincer complexes in the Suzuki-Miyaura coupling
reaction.31
3
3
performed using SHELXTL v6.10.
Table 8. Crystal data and structure refinement for 1g
Compound
Empirical formula
Formula weight (g mol )
1g
17 15 3
C H N S
293.38
0.47 × 0.28 × 0.27
yellow
-1
Crystal size (nm)
Color
Crystal system
Space group
a (Å)
Monoclinic
P21/c
11.1601 (7)
11.5158 (6)
12.7909 (6)
90
110.834 (2)
90
1536.37 (15)
4
Experimental
General considerations
b (Å)
c (Å)
α (°)
β (°)
All operations were carried out in open atmosphere. Reagents
used were of analytical grade available commercially and were
used as received. Column chromatography was performed
using 70–230 mesh silica gel and neutral alumina. The solvents
for chromatographic separations were distilled before use.
The equipment used for irradiation with IR energy was created
by employing an empty cylindrical metal vessel where an Number of collected reflections
Osram lamp (bulb model Thera-Therm, 250 W, 125 V) was
inserted.1
All compounds were characterized using IR spectra, recorded
with a Perkin-Elmer 283B or 1420 spectrophotometer, by
means of film and KBr techniques, and all data are expressed
in wavenumbers (cm ). Melting points were obtained with a
Melt-Temp II apparatus and are uncorrected. NMR spectra
were measured with a Varian Eclipse 300 MHz and Varian 500

(°)
3
V (Å )
Z
3
D
calc (g/cm )
1.268
31989
Number of independent
3
382, Rint = 0.0837
4,19,20
reflections (Rint)
Maximum and minimum
transmission
Data/restraints/parameters
Final R indices
0.875 and 0.796
3382 / 0 /191
R = 0.0438
-
1
[
I>2σ(I)]
wR
R = 0.1023, wR
1.011
Multi-scan
2
= 0.1090
R indices (all data)
2
= 0.0890
GoF(F2)
MHz, using CDCl
shifts are in ppm (δ), relative to tetramethylsilane.
3
, CH
2
Cl
2
and DMSO-d
6
as solvents. Chemical
Absorption correction method
8
| J. Name., 2012, 00, 1-3
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New Journal of Chemistry
Journal Name
ARTICLE
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
Crystallographic data for 1g are available in CIF format in the H-g), 7.28-7.34 (m, 3H, H-f, H-a), 7.85 (d, 1H, J = 3.3 Hz, H-b). 13
Supporting Information CCDC 186361.
C
View Article Online
DOI: 10.1039/C9NJ02977J
3 3 3
NMR (75 MHz, CDCl ) δ: 16.6 (CH -C=N), 43.4 (CH -N), 116.0 (C-f),
1
(
20.8 (C-h), 121.0 (C-a), 128.9 (C-g), 143.1 (C-b),150.4 (C-e), 155.3
General procedure for the synthesis of arylhydrazones 1a-i.
+
C-d), 169.1 (C-c); MS-EI (70 eV) m/z (%): 231 [M] (100). HR-
MS(DART) [M + H] (m/z) = 232.09111; calcd value for C12 S =
A solution of the corresponding arylhydrazine (2.6 mmol) in
ethanol (5 mL) was added dropwise to a magnetically stirred
solution of 2-thiazole carbonyl compounds (2.6 mmol) in
ethanol (5 mL) and 2 drops of acetic acid. The reaction mixture
was irradiated using an Osram lamp (bulb model Thera-Therm,
14 3
H N
2
1

1
32.09084 (ppm error δ: 0.27).
f. Yield 80 %. Yellow solid; mp 52-54°C; 66-67°C; FT-IR (ATR,
−1
2
3
max/cm ): 3100 (
486 (
s
1
, H-Csp ), 2920 (
s
, H-Csp ), 1589 (
, C=C, Ar); H NMR (300 MHz, CDCl ) δ: 2.20 (s, 3H, CH
-N), 6.98-7.01 (m, 3H, H-f, H-h), 7.23-7.34 (m,
s
, C=N),
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
s
3
3
-
2
50 W, 125 V) for time indicated in the table 1. The resulting
C=N), 4.85 (s, 2H, CH
8
2
solution was evaporated to dryness and the crude product was
chromatographed on silica gel, elution with Hexane/AcOEt
H, H-a, H-g, H-l, H-m, H-n), 7.80 (d, 1H, J = 3.0 Hz, H-b). 13C NMR
) δ: 16.8 (CH -C=N), 62.8 (CH -N), 118.7 (C-f), 120.7
3 3 2
C-h), 122.2 (C-n), 127.0 (C-a), 127.8 (C-m), 128.3 (C-g) 128.9 (C-l),
38.2 (C-k), 143.0 (C-b), 149.7 (C-e), 154.5 (C-d), 169.3 (C-c). MS-
DART (19 eV) m/z (%): 308 [M + 1] . HR-MS [M + H] (m/z) =
(75 MHz, CDCl
(99:1 v/v) allowed the product to be recovered as a yellow
(
1
solid.
−
1
1
3
a. Yield 66 %. Yellow solid; mp 71-73 °C; FT-IR (ATR, max/cm ):
+
2
3
035 (
s
, H-Csp ), 2917 (
s
, H-Csp ), 1581 (
s
, C=N), 1480 (
s
, C =C,
-C=N), 2.49 (s, 3H,
3
0
1
2
1
08.12262; calcd value for C18
.48).
18 3
H N S = 308.12214 (ppm error δ:
1
Ar); H NMR (300 MHz, CDCl
3
) δ: 2.03 (s, 3H, CH
3
3
CH ), 6.87 (s, 1H, H-b), 7.11-7.16 (m, 6H, H-f, H-h), 7.34 (t, 4H, 2H, J
g. Yield: 83 %. Yellow solid; mp 96-98 °C; FT-IR (KBr, max/cm−1):
1
3
=
1
8.7, J = 7.2 Hz, H-g); C NMR (75 MHz, CDCl
3
) δ: 14.0 (CH
3
-C=N),
3
2
921 (
586 (
s
 Csp -H), 3049 (
s
Csp -H, Ar), 1559, 1483 (
s
 C=C, Ar),
), 6.76
7.1 (CH ), 115.47 (C-b), 122.0 (C-f), 124.0 (C-h), 128.7 (C-e),129.2
3
1
s
 C=N); H NMR (300 MHz, CDCl
3
) δ: 2.38 (s, 3H, CH
3
(
3
C-g), 130.8 (C-a), 147.2 (C-d), 168.0 (C-c); MS-DART (19 eV) m/z (%):
08 [M + 1] . HR-MS (DART) [M + H] (m/z) = 308.12302; calcd value
(
s, 1H, H-b), 7.17-7.19 (m, 6H, H-f, H-h), 7.35 (s, 1H, H-d), 7.41-7.44
+
13
(m, 4H, H-g); C{1H} NMR (75 MHz, CDCl
3
) δ: 16.9 (CH
3
), 112.9 (C-
18
for C18H N
3
S = 308.12214 (ppm error δ: 0.88).
b), 122.2 (C-f), 125.2 (C-h), 129.8 (C-d), 130.0 (C-g), 142.5 (C-e),
52.8 (C-a), 166.3 (C-c); MS-EI (70 eV) m/z (%): 293 [M]+ (100), 168
−1
1
3
b. Yield 84 %. Yellow solid; mp 66-69°C; FT-IR (ATR, max/cm ):
1
2
3
095 (
s
, H-Csp ), 2922 (
s
, H-Csp ), 1583 (
) δ: 2.44(s, 3H, CH
-N), 6.85 (s, 1H, H-b), 6.95 (t, 1H, J = 8.7, J =
.8 Hz, H-h), 7.04 (d, 2H, J = 8.7 Hz, H-f), 7.30 (t, 2H, J = 8.7, J = 7.2
s
, C=N), 1462 (
s
, C =C,
-C=N), 2.49 (s, 3H,
+
[
C
12
H
10N] (98), 195 [C13
11
H N
2
]+ (19). HR-MS [M + H] (m/z) =
16 3
H N S = 294.10649 (ppm error δ: -
1
Ar); H NMR (300 MHz, CDCl
CH ), 3.31 (s, 3H, CH
3 3
7
3
3
2
0
1
3
94.10612; calcd value for C17
.37).
h. Yield: 97 %. Yellow solid; mp 80-82 °C; FT-IR (KBr, max/cm−1):
010, 2970, 2913 (, Csp -H); 3218, 3184, 3131 (, Csp -H); 1599
1
3
Hz, H-j). C NMR (75 MHz, CDCl
3
) δ: 16.7 (CH
3
-C=N), 17.2 (CH
3
),
3
2
4
3.3 (CH -N), 115.4 (C-b), 116.0 (C-f), 120.9 (C-h), 128.9 (C-g), 150.6
3
1
(
s
, C=N), 1562, 1523, 1491 (, C=C, Ar); H NMR (300 MHz, CDCl
3
)
(C-e),153.5 (C-a), 155.5 (C-d), 168.2 (C-c); MS-DART (19 eV) m/z
δ: 2.34 (s, 3H, CH
3
), 3.30 (s, 3H, CH
m, 1H, H-h), 7.23-7.25 (m, 4H, H-f, H-g), 7.58 (s, 1H, H-d); C NMR
75 MHz) δ : 17.0 (CH ), 33.5 (CH -N), 112.4 (C-b), 115.6 (C-f), 121.7
3
-N), 6.64 (s, 1H, H-b), 6.86-6.92
+
(%): 246 [M+ 1] . HR-MS (DART) [M + H] (m/z) = 246.10644; calcd
13
(
(
(
16
value for C13H N
3
S = 246.10649 (ppm error δ: 0.05).
3
3
−1
1
3
c. Yield 67 %. Yellow solid; mp 80-82 °C; FT-IR (ATR, max/cm ):
C-h), 126.5 (C-d), 129.0 (C-g), 146.7 (C-e), 152.6 (C-a), 166.9 (C-c).
MS-DART (19 eV) m/z (%): 232 [M+1] . HR-MS (DART) [M + H] (m/z)
2
3
096 (
s
, H-Csp ), 2913 (
s
, H-Csp ), 1591 (
s
, C=N), 1491(
-C=N), 2.48 (s, 3H,
-N), 6.86 (s, 1H, H-b), 6.99-7.02 (d, 3H, H-f, H-
s
, C =C,
+
1
Ar); H NMR (300 MHz, CDCl
3
) δ: 2.22 (s, 3H, CH
3
=
0
1
2
232.09109; calcd value for C12
.25).
14 3
H N S = 232.09084 (ppm error δ:
CH
h), 7.27-7.36 (m, 7H, H-g, H-l, H-m, H-n); C NMR (75 MHz, CDCl
δ: 16.8 (CH -C=N), 17.2 (CH ), 62.8 (CH -N), 115.4 (C-b), 118.5 (C-f),
22.0 (C-h), 127.0 (C-n), 127.8 (C-m), 128.3 (C-g) 128.9 (C-l),138.3
3
) 4.87 (s, 2H, CH
2
1
3
3
)
i. Yield: 80%. Yellow solid; mp 88-90 °C; FT-IR (KBr, max/cm−1):
979, 2952, 2922 (, Csp -H); 3096, 3061, 3034 (, Csp -H); 1596
3
3
2
3
2
1
1
(
s
, C=N), 1560, 1520, 1495 (, C=C, Ar); H NMR (300 MHz, CDCl
3
)
(C-k), 149.7 (C-e),153.0 (C-a), 155.3 (C-d), 168.2 (C-c); MS-DART (19
3 2
δ: 2.37 (s, 3H, CH ), 5.15 (s, 2H, CH -N), 6.72 (s, 1H, H-b), 7.01 (m,
H, H-h), 7.02 (d, 2H, J = 8.4 Hz, H-f), 7.29-7.38 (m, 7H, H-g, H-l, H-
+
eV) m/z (%): 321 [M+ 1] . HR-MS (DART) [M + H] (m/z) =
1
3
0
1
3
22.13779; calcd value for C19
.33).
d. Yield 70 %. Yellow solid; mp 108-110 °C; FT-IR (ATR, max/cm ):
H
20
N
3
S = 322.14115 (ppm error δ:
13
m, H-n), 7.55 (s, 1H, H-e); C NMR (75 MHz, CDCl
5
(
1
3
) δ: 16.9 (CH
3
),
2
1.2 (CH -N), 112.6 (C-b), 115.3 (C-f), 121.9 (C-h), 125.8 (C-l), 127.5
C-d), 129.0 (C-m), 129.1 (C-g), 134.2 (C-k), 146.9 (C-e), 152.6 (C-a),
66.7 (C-c); MS-DART (19 eV) m/z (%): 308 [M+1] . HR-MS [M + H]
18 3
m/z) = 308.12156; calcd value for C18H N S = 308.12214 (ppm
−1
2
3
068 (
s
, H-Csp ), 2927 (
s
, H-Csp ), 1584 (
s
, C=N), 1479 (
s
, C =C,
-C=N), 7.12-7.15
+
1
Ar); H NMR (300 MHz, CDCl
3
) δ: 2.02 (s, 3H, CH
3
(
(
m, 6H, H-f, H-h), 7.29-7.367 (m, 5H, H-g, H-a), 7.81 (d, 1H, J = 3.0
error δ: -0.58).
1
3
Hz, H-b). C NMR (75 MHz, CDCl
3 3
) δ: 16.9 (CH -C=N), 120.7 (C-a),
General procedure for the synthesis of palladacycles 2a-i.
1
22.0 (C-f), 124.0 (C-h), 129.1 (C-g), 142.9 (C-b),147.2 (C-e), 152.5
+
(
[
(
C-d), 169.7 (C-c); MS-DART (19 eV) m/z (%): 293 [M + 1] . HR-MS To a suspension of PdCl (1.2 mmol) in water (10 mL) was irradiated
M + H] (m/z) = 294.10614; calcd value for C17
ppm error δ: -0.35).
2
16
H N
3
S = 294.10649 using an Osram lamp (bulb model Thera-Therm, 250 W, 125 V) for
10 minutes; then, a solution of the corresponding ligand (1a-i) in
−
1
1
3
e. Yield 68 %. Yellow solid; mp 52-54°C; FT-IR (ATR, max/cm ): etanol (5 mL) was added. The reaction was irradiated with IR energy
2
3
086 (
s
, H-Csp ), 2896 y 2805 (
1
s
, H-Csp ), 1580 (
s
, C=N), 1477 (
s
,
for time indicated in the table 2. Thereafter, the reaction was
Cl
2
C =C, Ar); H NMR (300 MHz, CDCl
3
) δ: 2.45 (s, 3H, CH
3
-C=N), 3.32 (s, cooled at room temperature; the mixture was extracted with CH
2
3
3
H, CH -N), 6.96 (t, 1H, J = 7.8 Hz, H-h), 7.06-7.09 (d, 2H, J = 7.8 Hz, (3 X 10 mL). The combined organic layers were dried over
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 9
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New Journal of Chemistry
Page 10 of 13
ARTICLE
Journal Name
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
+
anhydrous sodium sulfate. The product was purified by column (%): 372 [M] (3); Anal. calcd for C12
chromatography on neutral alumina. Elution with CH
recover the pure product as an orange solid.
H
12ClN
3
PdS: C 38.73, H 3.25, N
View Article Online
DOI: 10.1039/C9NJ02977J
2 2
Cl allowed to 11.29, S 8.61; found C 38.71, H 3.33, N 11.24, S 8.67.
−1
2f. Yield 75 %. orange solid; mp 238 °C (dec); FT-IR (ATR, max/cm ):
−
1
2
3
2
a. Yield 90 %. orange solid; mp 220 °C (dec); FT-IR (ATR, max/cm ): 3044 (
s
, H-Csp ), 2921 (
, C=N), 1488(s, C =C, Ar); H NMR (500 MHz, CD
500 MHz) δ: 1.78 (s, 3H, CH -C=N), 2.66 (s, 3H, CH -N), 6.23 (dd, 1H, J = 10Hz, H-g), 6.68 (td, 1H, J = 5Hz, H-h), 6.94
s
, H-Csp ), 1540 (
Cl ) δ: 2.35 (s, 3H, CH
s
s
, C=N), 1434 ( , C =C,
2
3
1
3
104 (
s
, H-Csp ), 2923 (
Cl
s
H-Csp ), 1552 (
s
2
2
3
-C=N), 4.70 (s, 2H,
1
Ar); H NMR (CD
2
2
3
2
3
CH -N), 6.04 (d, J =10 Hz, 1H, H-g), 6.69 (t, J = 15 Hz, 1H, H-h), 6.80 (t, 1H, J = 15Hz, H-i), 7.32-7.34 (m, 5H, H-n, H-l, H-m), 7.38-7.40 (m,
1
3
(
(
t, J = 15 Hz, 1H, H-i), 7.08 (d,1H, H-j), 7.31 (s, 1H, H-b), 7.48-7.55 2H, H-j, H-b), 7.48 (d, 1H, J = 5Hz, H-a); C NMR (125 MHz, CD
m, 5H, H-m, H-n, H-l); 13C NMR (125 MHz, CD
Cl ) δ: 16.8 (CH δ: 18.2 (CH -C=N), 67.0 (CH -N), 111.0 (C-g), 119.7 (C-h), 121.2 (C-i),
-N), 112.1 (C-g), 116.2 (C-h), 121.8 (C-i), 125.1 (C-j), 122.1 (C-j), 125.7 (C-m), 126.1 (C-l), 127.74 (C-n), 127.8 (C-k), 129.1
28.4 (C-m), 129.1 (C-n), 130.1 (C-l), 130.5 (C-e), 134.9 (C-b), 138.2 (C-a), 129.3 (C-b), 134.9 (C-e), 137.9 (C-f), 158.4 (C-d), 161.4 (C-c).
2 2
Cl )
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
2
2
3
-
3
2
C=N), 17.8 (CH
1
3
+
+
+
(C-f), 142.2 (C-k), 144.3 (C-a) 152.0 (C-d), 156.8 (C-c). MS-FAB (5 MS-FAB (5 eV) m/z (%): 448 [M+ 1] (3) Anal. calcd for
+
eV) m/z (%): 448 [M + H] (3); Anal. calcd for C18
H16ClN
3
PdS: C 48.23,
C
18
H
16ClN
3
PdS: C 48.23, H 3.60, N 9.37, S 7.15; found C 48.33, H
3.66, N 9.41, S 7.18.
b, Yield 94 %. orange solid; mp 235 °C (dec); FT-IR (ATR, max/cm ): 2g. Yield: 60 %. orange solid; mp 250°C (dec); FT-IR (KBr, max/cm−1):
H 3.60, N 9.37, S 7.15; found C 47.98, H 3.56, N 9.67, S 7.01.
2
−
1
2
3
3
3
116 (
s
, H-Csp ), 2924 (
s
, H-Csp ), 1524(
) δ: 2.49 (s, 3H, CH
-N), 6.52 (d, 1H, H-g), 6.62 (t, 1H, H-h), 6.94
s
, C=N), 1444 (
s
, C =C, 3103 (
s
, H-Csp
2
), 2922 (
s s s
, H-Csp ), 1529 ( , C=N), 1441 ( , C=C,
, 300 MHz) δ: 2.40 (s, 3H, H-a), 5.73 (d, 1H,
Hh-Hi =8.1 Hz, H-h), 6.60 (m, 1H, H-i), 6.79 (m, 1H, H-j), 7.34 (d, 1H,
Hk-Hj = 7.2 Hz, H-k), 7.55 (d, 2H, H-m); 7.62 (s, 1H, H-e), 7.67-7.73
1
1
Ar); H NMR (300 MHz, DMSO-d
6
3
-C=N), 2.60 (s, Ar); H NMR (DMSO-d
6
3
(
H, CH
t, 1H, H-i), 7.24 (d, 1H, H-j), 7.07 (s, 2H, H-b); C NMR (75 MHz,
DMSO-d ) δ: 17.0 (CH -C=N), 18.6 (CH ), 45.7 (CH
19.8 (C-h), 121.6 (C-i), 123.8 (C-j), 126.1 (C-b), 135.05 (C-f), 151.2 (C-a), 110.6 (C-h), 115.9 (C-c), 117.5 (C-i), 118.3 (C-j), 121.5 (C-k),
3
), 3.49 (s, 3H, CH
3
J
J
1
3
1
3
6
3
3
3 6
-N), 112.8 (C-g), (m, 3H, H-c, Ar-H. H-n, H-o); C NMR (DMSO-d , 75 MHz) δ: 16.7
1
+
(
3
C-e), 155.8 (C-a), 161.6 (C-d), 162.7 (C-c); MS-FAB (5 eV) m/z (%): 126.1 (C-m), 128.3 (C-n), 129.8 (C-o), 130.2 (C-e), 135.3 (C-l), 154.2
86 [M ] (5); Anal. calcd for C13
+
+
H
14ClN
3
PdS: C 40.43, H 3.65, N 10.88, (C-f), 155.1 (C-g), 167.3 (C-b), 168.2 (C-d); MS-FAB (5 eV) m/z (%):
+
S 8.30; found C 40.46, H 3.70, N 10.86, S 8.20.
433 [M ] (4), Anal. calcd for C17
H
14ClN
3
PdS: C 47.02, H 3.25, N 9.68,
−
1
2
c. Yield 50 %. orange solid; mp 252°C (dec); FT-IR (ATR, max/cm ): S 7.38; found C 47.06, H 3.22, N 9.68, S 7.49.
2
3
s s
, C=N), 1442 (
, C=C, 2h. Yield: 60 %. orange solid; mp 276°C (dec); FT-IR (KBr, max/cm−1):
2
925 (
s
, H-Csp ), 2861 (
s
, H-Csp ), 1525 (
Cl ) δ: 2.36 (s, 3H, CH
1
2
3
Ar); H NMR (500 MHz, CD
2
2
3
-C=N), 2.58 (s, 3H, 3083, 3053 (, H-Csp ), 2921(
-N) 6.25 (dd, 1H, J = 5 Hz, H-g), 6.68 (t, 1H, J = 10 1493 (, C=C, Ar). H NMR (DMSO-d
s
s
, H-Csp ), 1539 ( , C=N), 1511,
1
CH
3
), 5.0 (s, 1H, CH
2
6
, 300 MHz) δ: 2.41 (s, 3H, H-a),
Hz, H-h), 6.85 (t, 1H, H-i), 7.05 (s, 1H, H-b), 7.30-7.33 (m, 3H, H-m, 3.68 (s, 3H, NCH
3
), 6.45 (d, 1H, JHh-Hi = 8.1 Hz, H-h), 6.55 (m, 1H, H-
H-n), 7.37-7.40 (m, 2H, H-l), 7.44 (d, 1H, H-j); C NMR (125 MHz, i), 6.88 (m, 1H, H-j), 7.21 (d, 1H, JHk-Hj = 7.2 Hz, H-k), 7.45 (s, 1H, H-
CD Cl ) δ: 16.7 (CH -C=N), 18.2 (CH ) 60.1 (CH , 75 MHz) δ: 16.7 (C-a), 33.5
-N), 111.1 (C-g), e), 7.97 (s, 1H, H-c); 13C NMR (DMSO-d
16.6 (C-h), 121.8 (C-i), 125.5 (C-j), 126.3 (C-m), 127.7 (C-n), 128.6 (NCH ), 110.6 (C-h), 115.9 (C-c), 118.3 (C-i), 121.5 (C-k), 126.1 (C-j),
C-k), 129.0 (C-l), 130.8 (C-e), 134.7 (C-b), 135.9 (C-f), 143.9 9(C-a) 128.2 (C-e), 154.3 (C-f), 155.1 (C-g), 166.9 (C-b), 167.6 (C-d); MS-
1
3
2
2
3
3
2
6
1
(
3
+
+
+
+
1
56.5 (C-d), 159.2 (C-c); MS-FAB (5 eV) m/z (%): 462 [M] (3); Anal. FAB (5 eV) m/z (%): 372 [M ] (5). Anal. calcd for C12
PdS: C 49.36, H 3.92, N 9.09, S 6.93; found C 38.73, H 3.25, N 11.29, S 8.61; found: C 39.88, H 3.39, N 11.36, S
9.33, H 3.95, N 9.37, S 9.87. 8.66.
d. Yield 96 %. orange solid; mp 246 °C (dec). FT-IR (ATR, max/cm ): 2i. Yield: 65 %. mp 266°C (dec). FT-IR (KBr, max/cm ): 3081, 3036, (,
3
H12ClN PdS: C
calcd for C13H18ClN
3
4
2
3
=
1
−1
−1
2
3
2
3
044 (
s
1
, H-Csp ), 2923, 2862 (
s
, H-Csp ), 1544 (
Cl ) δ: 1.76 (s, 3H, CH
H, J = 10 Hz, H-g), 6.65 (t, 1H, J = 15 Hz, H-h), 6.77 (t, 1H, J = 15 Hz, 3H, NCH
s
, C=N), 1479 (
s
, C H-Csp ), 2961, 2626, (, H-Csp ) 1539, (
-C=N), 5.99 (d, C=C, Ar); H NMR (DMSO-d
s
, C=N), 1504, 1449, (,
, 300 MHz) δ: 2.43 (s, 3H, H-a), 3.50 (s,
), 6.51 (d, 1H, JHh-Hi = 7.2 Hz, H-h), 6.61 (m, 1H, H-i), 6.89
1
C, Ar); H NMR (500 MHz, CD
2
2
3
6
2
H-i), 7.36 (dd, 1H, J = 10Hz, H-j), 7.47-7.56 (m, 5H, H-m, H-l, H-b), (m, 1H, H-j), 7.19 (d, 1H, JHk-Hj = 6.6 Hz, H-k), 7.24-7.39 (m, 5H, H-m,
.67 (m, 1H, H-n), 7.82 (d, 1H, J = 5Hz, H-a). 13C NMR (125 MHz, H-n and H-o), 7.49 (s, 1H, H-e), 8.0 (s, 1H, H-c). C NMR (DMSO-d
13
,
7
6
CD
C-j), 128.7 (C-m), 128.9 (C-a). 129.6 (C-e), 130.3 (C-n), 130.8 (C-l), (C-i), 118.2 (C-j), 121.6 (C-k), 126.2 (C-m), 128.1 (C-e), 129.0 (C-n),
32.4 (C-b), 135.3 (C-f), 142.7 (C-k), 158.9 (C-d), 161.5 (C-c). MS- 130.6 (C-o), 136.0 (C-l), 154.3 (C-f), 156.1 (C-g), 166.1 (C-b), 168.1
2 2 3 2
Cl ) δ: 18.0 (CH -C=N), 112.2 (C-g), 120.7 (C-h), 122.3 (C-i), 125.3 75 MHz) δ: 16.1 (C-a), 34.5 (NCH ), 110.5 (C-h), 116.0 (C-c), 117.1
(
1
+
+
+
+
FAB (5 eV) m/z (%): 434 [M+ 1] (5); Anal. calcd for C17
H
14ClN
3
PdS: (C-d); MS-FAB (5 eV) m/z (%): 448 [M ] (5). Anal. calcd for
PdS: C 48.23, H 3.60, N 9.37, S 7.15; found: C 48.37, H
.34.2e. Yield 60 %. orange solid; mp 226 °C (dec); FT-IR (ATR, 3.63, N 9.28, S 7.25.
C 47.02, H 3.25, N 9.68, S 7.38; found C 47.05, H 3.26, N 9.64, S
18 3
C H16ClN
7

1
−1
2
3
max/cm ): 3112 (
s
, H-Csp ), 2908 (
s
, H-Csp ), 1530 (
) δ: 2.61(s, 3H, CH
-N), 6.5 (dd, 1H, J = 8.1, 1.2 Hz, H-g), 6.6 (td,
H, J = 15, 1.5Hz, H-h), 6.94 (td, 1H, J = 15, 1.5Hz, H-i), 7.1 (dd, 1H, J
7.5,1.5Hz, H-j), 7.7 (d, 1H, J = 3Hz, H-b), 8.1 (d, 1H, J = 3Hz, H-a);
s
, C=N),
General procedure for Suzuki-Miyaura coupling reactions.
1
441 (
s
, C =C, Ar). H NMR (300 MHz, DMSO-d
6
3
-
Inside a 50-mL round-bottom flask, a mixture of aryl halide (0.5
mmol), phenylboronic acid (0.6 mmol), and base (1 mmol) was
placed in 3 mL of solvent. An appropriate amount of the complex
(2) from a stock solution prepared in DMA was added and the
reaction mixture was irradiated with IR energy for the time
reported in Tables 3-6. Thereafter, the reaction was cooled at room
temperature; the mixture was diluted with 10 mL of water and
C=N), 3.47(s, 3H, CH
3
1
=
1
3
6 3 3
C NMR (75 MHz, DMSO-d ) δ: 18.6 (CH -C=N), 46.0 (CH -N), 111.9
(C-g), 119.0 (C-h), 121.9 (C-i, 124.0 (C-j), 125.1 (C-a), 126.0 (C-b),
+
1
35.6 (C-f), 150.0 (C-e), 158.0 (C-d), 164.0 (C-c); MS-FAB (5 eV) m/z
1
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Estudiante-Negrete, R. A. Toscano, S. HernándVeiezw-OArrtticelegOa,nliDne.
extracted with hexane or AcOEt (3 x 10 mL). The combined organic
layers were dried over anhydrous sodium sulfate. The crude
product was finally purified by flash column chromatography on
silica gel to give the isolated products.
Morales-Morales and J.-M. Grévy, J. Organomet. Chem.,
DOI: 10.1039/C9NJ02977J
2
014, 749, 287-295.
5
6
N. Selander and K. Szabó, Chem. Rev. 2011, 111, 2048–2076.
E. M. Schuster, M. Botoshansky and M. Gandelman, Angew.
Chem., Int. Ed., 2008, 47, 4555–4558.
J.-L. Niu, X.-Q. Hao, J.-F. Gong and M.-P. Song, Dalton Trans.,
2011, 40, 5135–5150.
B. Inés, R. SanMartin, F. Churruca, E. Domínguez, M. Karmele
Urtiaga and M. I. Arriortua, Organometallics, 2008, 27, 2833–
2839.
X-Q. Hao, Y-N. Wang, J-R. Liu, K-L. Wang, J-F. Gong and M-P.
Song, J. Organomet. Chem., 2010, 695, 82–89.
0 (a) Q-L. Luo, J-P. Tan, Z-F. Li, Y. Qin, L. Ma and D-R. Xiao,
Dalton Trans., 2011, 40, 3601-3609; (b) Q-L. Luo, J-P. Tan, Z-
F. Li, W-H. Nan, and D-R. Xiao, J. Org. Chem. 2012, 77,
8332−8337.
1 V. A. Kozlov, D. V. Aleksanyan, Y. V. Nelyubina, K. A.
Lyssenko, P. V. Petrovskii, A. A. Vasil’ev and I. L. Odinets,
Organometallics, 2011, 30, 2920–2932.
The purified product was identified by means of mp determination
1
13
7
8
and by H and C-NMR; the data obtained are consistent with
3
4
literature.
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Conclusions
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1
In conclusion, we have synthesized nine novel [NNC]-
tridentate ligands containing both a hydrazone and a thiazolyl
moiety as coordination sites. Direct cyclopalladation of these
ligands afforded non-symmetric cyclopalladated pincer
complexes 2a-i in good yields. These palladacycles proved to
be excellent pre-catalysts for the Suzuki-Miyaura cross-
coupling of a variety of bromoarenes and phenylboronic acids.
The pincer complex 2a, also promoted the reaction with
activated aryl chlorides. In all cases, the cross-coupling
reaction was conducted under IR irradiation in water as
solvent. The experimental evidences allow us to propose the
feasible formation of a hydroxo-palladium complex as first
intermediate in the formation of the catalytic specie involved
1
1
2 (a) D. V. Aleksanyan, V. A. Kozlov, N. E. Shevchenko, V. G.
Nenajdenko, A. A. Vasil’ev, Y. V. Nelyubina, I. V. Ananyev, P.
V. Petrovskii and I. L. Odinets, J. Organomet. Chem., 2012,
7
11, 52–61; (b) V. A. Kozlov, D. V. Aleksanyan, Y. V.
Nelyubina, K. A. Lyssenko, A. A. Vasil’ev, P. V. Petrovskii, and
I. L. Odinets, Organometallics, 2010, 29, 2054–2062
3 M. P. Singh, F. Saleem, G. K. Rao, S. Kumar, H. Joshi and A. K.
Singh, Dalton Trans., 2016, 45, 6718–6725.
1
in the Suzuki cross-coupling reaction. The presence of nBu
4
NBr 14 (a) F. Ortega-Jiménez, F. X. Domínguez-Villa, A. Rosas-
Sánchez, G. Penieres-Carrillo, J. G. López-Cortés and M. C.
in basic conditions can produce the formation in situ of
nBu NOH, which would favor the reaction exchange from the
Ortega-Alfaro, Appl. Organometal. Chem., 2015, 29, 556–
60; (b) F. Ortega-Jiménez, J. G. Penieres-Carrillo, J. G. López-
Cortés, M. C. Ortega-Alfaro and S. Lagunas-Rivera, Chin. J.
Chem., 2017, 35, 1881–1888.
4
5
halide to hydroxo-palladium intermediates. The coupled
products of these reactions were obtained in moderated to
excellent yields, short reaction times and low catalyst loading.
15 (a) I. Hussain, J. Capricho, and M. A. Yawer, Adv. Synth.
Catal., 2016, 358, 3320–3349; (b) A. Chatterjee and T. R.
Ward, Catal. Lett., 2016, 146, 820–840; (c) L. Yin and J.
Liebscher, Chem. Rev., 2007, 107, 133–173; (d) R. Martin and
S. L. Buchwald, Acc. Chem. Res., 2008, 41, 1461-1473.
16 (a) A. T. K. Koshvandi, M. M. Heravi and T. Momeni, Appl.
Organomet. Chem., 2018, 32, e4210; (b) O. Baudoin, M.
Cesario, D. Guenard and F. Gueritte, J. Org. Chem., 2002, 67,
199–1207; (c) K. T. Wong, T S. Hung, Y. Lin, C. C. Wu, G. H.
Lee, S. M. Peng, C. H. Chou and Y. O. Su, Org. Lett., 2002, 4,
13–516.
7 (a) J. Martínez and R. Miranda (February 9th 2019). Infrared
Irradiation, an Excellent, Alternative Green Energy Source
Conflicts of interest
“There are no conflicts to declare”.
1
Acknowledgements
We thank L. Velasco, J. Pérez, M. P. Orta Pérez and M. Cruz-
Villafañe for their technical support. The authors also thank
DGAPA-PAPIIT-IN215116 and FES Cuautitlán-UNAM PIAPI1806.
5
1
[
Online First], IntechOpen, DOI: 10.5772/intechopen.83805.
Available from: https://www.intechopen.com/online-
first/infrared-irradiation-an-excellent-alternative-green-
energy-source. And references cited there; (b) R. Escobedo,
R. Miranda and J. Martínez. Int. J. Mol. Sci., 2016, 17, 1-26.
Notes and references
1
(a) Pincer Compounds Chemistry and Applications, ed. D.
Morales-Morales, Elsevier, Amsterdam. 2018; (b)
Palladacycles: Synthesis Characterization and Applications,
ed. J. Dupont and M. Pfeffer, Wiley-VCH, Weinheim, 2008.
(a) The Chemistry of Pincer Compounds, ed. D. Morales-
Morales and C. M. Jensen, Elsevier Science, Amsterdam,
18 C. O. Kappe, D. Dallinger and S. S. Murphree, Practical
Microwave Synthesis for Organic Chemists Strategies,
Instruments and Protocols, Wiley-VCH, Weinheim, 2009.
9 F. Ortega-Jiménez, J. G. Penieres-Carrillo, S. Lagunas-Rivera,
J. G. López-Cortés, C. Alvarez-Toledano and M. C. Ortega-
Alfaro, RSC Adv., 2015, 5, 80911–80918.
20 J. A. Balam-Villarreal, C. I. Sandoval-Chávez, F. Ortega-
Jiménez, R. A. Toscano, M. P. Carreón-Castro, J. G. López-
Cortés and M. C. Ortega-Alfaro, J. Organomet. Chem., 2016,
18, 7–14.
1 (a) W. Cao, Y. Liu, T. Zhang and J. Jia, Polyhedron, 2018, 147,
2-68; (b) G. Yakalı, A. Çakıcı, C. Eke, G. T. Cin, M. Aygün, J.
1
2
2
007; (b) Pincer and pincer-type complexes, ed. K. J. Szabó
and O.F. Wendt, Wiley-VCH, Weinheim. 2014; (c) M. Asay
and D. Morales-Morales, Dalton Trans. 2015, 44 17432–
17447.
(a) D. Morales-Morales, H. Valdes, M. A. García-Eleno and D.
Canseco-Gonzalez, ChemCatChem., 2018, 10, 3136-3172; (b)
M. E. van der Boom and D. Milstein, Chem. Rev., 2003, 103,
8
3
4
2
6
Mol. Struct., 2017, 1134, 244–252; (c) Y.J. Wei, F.W. Wang, J.
Struct. Chem., 2011, 52, 755–759.
1
759–1792; (c) J. Dupont, C. S. Consorti and J. Spencer,
Chem. Rev., 2005, 105, 2527-2571.
2
2 G.W. Parshall, Acc. Chem. Res., 1970, 3, 139-144
(a) D. Morales-Morales, R. Redón, C. Yung and C. M. Jensen,
Chem. Commun., 2000, 1619–1620. (b) S. Ramírez-Rave, F.
This journal is © The Royal Society of Chemistry 20xx
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ARTICLE
Journal Name
1
2
3
4
5
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1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
2
2
3 M. Ghedini, I. Aiello, A. Crispini and M. La Deda, Dalton
View Article Online
DOI: 10.1039/C9NJ02977J
Trans., 2004, 1386–1392
4 (a) A. Fernández, D. Vázquez-García, J. J. Fernández, M.
López-Torres, A. Suárez and J. M. Vila, J. Organomet. Chem.,
2005, 690, 3669-3679; (b) C. López, S. Pérez, X. Solans and
M. Font-Bardia, J. Organomet. Chem., 2002, 650, 258-267;
(
c) X. Riera, A. Caubet, C. López, V. Moreno, E. Freisinger, M.
Willermann and B. Lippert, J. Organomet. Chem., 2001, 629,
7-108; (d) X. Riera, C. López, A. Caubet, V. Moreno, X.
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
Solans and M. Font-Bardia, Eur. J. Inorg. Chem., 2001, 2135-
2141.
5 (a) Q-L. Luo, J-P. Tan, Z-F. Li, Y. Qin, L. Ma and D-R. Xiao,
Dalton Trans., 2011, 40, 3601-3609; (b) P. Chellan, S. Nasser,
L. Vivas, K. Chibale, and G. S. Smith, J. Organomet. Chem.,
2
2
010, 695, 2225-2232; (c) F. Ortega-Jiménez, J. G. López-
Cortés, M. C. Ortega-Alfaro, A. Toscano, G. Penieres, R.
Quijada, and C. Alvarez, J. Organomet. Chem., 2005, 690,
4
54–462; (d) F. Ortega-Jiménez, E. Gómez, P. Sharma, M. C.
Ortega-Alfaro, R. A. Toscano, and C. Alvarez-Toledano, Z.
Anorg. Allg. Chem., 2002, 628, 2104-2108; (e) J. Albert, A.
González, J. Granell, R. Moragas, X. Solans, and M. Font-
Bardía, Dalton Trans., 1998, 1781–1785.
26 (a) T. Stensitzki, Y. Yang, V. Kozich, A. A. Ahmed, F. Kössl, K.
Oliver and H. Karsten, Nat. Chem., 2018, 10, 126-131; (b) S.
K. Lee, A. G, Suits, H. B, Schlegel and W. J. Li, Phys. Chem.
Lett., 2012, 3, 2541−2547.
2
7 (a) D.R. Anton and R.H. Crabtree, Organometallics, 1983, 2,
55-859; (b) A. Avila-Sorrosa, H. A. Jiménez-Vázquez, A.
8
Reyes-Arellano, J. R. Pioquinto-Mendoza, R. A. Toscano, L.
González-Sebastián, and D. Morales-Morales, J. Organomet.
Chem., 2016, 819, 69-75; (c) S. Ramírez-Rave, D. Morales-
Morales, and J-M. Grévy, Inorg. Chim. Acta., 2017, 462, 249–
2
55.
2
2
8 (a) J. L. Serrano, J. Pérez, L. García, G. Sánchez, J. García, P.
Lozano, V. Zende and A. Kapdi, Organometallics, 2015, 34,
5
2
9 (a) C. Amatore, A. Jutand and G. Le Duc, Chem. Eur. J., 2011,
1
22−533; (b) D. J. Nelson and S. P. Nolan, Coord. Chem. Rev.,
017, 353, 278-294.
7, 2492–2503; (b) C. Amatore, A. Jutand and G. Le Duc,
Chem. Eur., J. 2012, 18, 6616–6625; (c) C. Amatore, G. Le Duc
and A. Jutand, Chem. Eur. J., 2013, 19, 10082–10093.
0 J. Sherwood, J. H. Clark, I.J. S. Fairlamb and J. M. Slattery,
Green Chem., 2019, 21, 2164–2213.
1 (a) F. Lucio-Martínez, L. A. Adrio, P. Polo-Ces, J. M.
Ortigueira, J. J. Fernández, H. Adams, M. T. Pereira and J. M.
Vila, Dalton Trans., 2016, 45, 17598–17601; (b) V.
Arumugam, W. Kaminsky, N. S. P. Bhuvaneshc and D.
Nallasamy, RSC Adv., 2015, 5, 59428–59436; (c) I. Vicente-
Hernández, M.-T. Chicote, J. Vicente and D. Bautista, Chem.
Commun., 2016, 52, 594-596; (d) H. Zhang and A. Lei, Dalton
Trans., 2011, 40, 8745–8754.
3
3
3
2 G. Altomare, C. Cascarano, A. Giacovazzo, M. C. Burla, G.
Polidori and M. Canalli, J. Appl. Crystallogr., 1994, 27, 435.
3 G. M. Sheldrick, Acta Crystallogr., 2008, A64, 112.
4 (a) L. Bai and J-X. Wang, Adv. Synth. Catal., 2008, 350, 315–
3
3
3
20; (b) X. Li, W. Che, H. Chang, Z. Shao and W. Wei,
Synthesis, 2014, 46, 1593–1602; (c) J. A. Weeden, R. Huang,
K. D. Galloway, P. W. Gingrich and B. J. Frost, Molecules,
2011, 16, 6215–6231; (d) H. Liu, H. Liu, R. Li and H. Chen,
Tetrahedron Lett., 2014, 55, 415–418; (e) B. B. A. Tairai, P. K.
Bhattacharyya and P. Das, Appl. Organometal. Chem., 2016,
3
0, 519–523; (f) V. Ramakrishna and N. D. Reddy, Dalton
Trans., 2017, 46, 8598–8610; (g) K. R. Balinge, A. G. Khiratkar
and P. R. Bhagat, J. Organomet. Chem., 2018, 854, 131-139;
(h) C. B. Baltus, N. J. Press, M. D. Antonijevic, G. J. Tizzard, S.
J. Coles, J. Spencer, Tetrahedron, 2012, 45, 9272-9277; (i) J.
Song, H. Zhao, Y. Liu, H. Han, Z. Li, W. Chu and Z. Sun, New J.
Chem., 2017, 41, 372–376.
1
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Table of Contents
Thiazole-based non-symmetric NNC-Palladium pincer complexes as
catalytic precursors for the Suzuki–Miyaura C-C coupling
Martín Camacho-Espinoza, Alberto Reyes-Deloso, R. Alfredo Toscano, J. Guillermo Penieres-Carrillo, José G.
López-Cortés, M. Carmen Ortega-Alfaro and Fernando Ortega-Jiménez
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New non-symmetric pincer palladacycle, containing a [N,N,C] tridentate hydrazone and bearing a
thiazolyl moiety have been synthetized and their catalytic activity in the Suzuki–Miyaura cross
coupling reaction have been tested using water as solvent, under aerobic conditions. The cross-
coupling reaction was conducted under IR irradiation, allowing to decrease the reaction times.