Synthesis and X-ray structure of neutral Pd(IV) hydride complexes supported by β-ketoimine ligands

Article abstract of DOI:10.1016/j.poly.2010.02.016

A series of neutral palladium(IV) hydride complexes supported by β-ketoimine ligands was synthesized. Reaction of dichlorobis(acetonitrile)palladium(II) with β-ketoamines (1-4) in dichloromethane at room temperature generated dark red solids of [PdCl

Full text of DOI:10.1016/j.poly.2010.02.016

Polyhedron 29 (2010) 1692–1696
Contents lists available at ScienceDirect
Polyhedron
journal homepage: www.elsevier.com/locate/poly
Synthesis and X-ray structure of neutral Pd(IV) hydride complexes supported
by b-ketoimine ligands
b
c
a
Najoua Belhaj Mbarek Elmkacher a, , Mongi Ben Amara , M’hamed Ali Hamza , Faouzi Bouachir
*
a Laboratoire de Chimie de Coordination, Département de Chimie, Faculté des Sciences de Monastir, Avenue de l’Environnement, 5019 Monastir, Tunisia
b Laboratoire des matériaux inorganiques, Département de Chimie, Faculté des Sciences de Monastir, Avenue de l’Environnement, 5019 Monastir, Tunisia
c Département de Chimie, Faculté des Sciences de Monastir, Avenue de l’Environnement, 5019 Monastir, Tunisia
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 2 June 2009
Accepted 11 February 2010
Available online 14 February 2010
A series of neutral palladium(IV) hydride complexes supported by b-ketoimine ligands was synthesized.
Reaction of dichlorobis(acetonitrile)palladium(II) with b-ketoamines (1–4) in dichloromethane at room
temperature generated dark red solids of [PdCl2(b-ketoimine)(H)] (6–9) in which the central carbon of
the ketoimine ligand is
r-bound to the palladium. All the new complexes have been characterized by
NMR and IR spectroscopy. The structure of complex(9) has been solved by X-ray crystallography.
Ó 2010 Elsevier Ltd. All rights reserved.
Keywords:
Hydride
b-Ketoimine ligands
Palladium complexes
1. Introduction
Palladium hydrides are of special interest due to their excep-
tional relevance to catalysis. Perhaps, no other metal can compete
Since the concept of hemilabile bidentate ligands was intro-
duced by Jeffrey and Rauchfuss [1] various combinations of differ-
ent donors have been studied [2–10].
Ligands of the type O–Y (where Y is N or S) are particularly
interesting to mixed-ligand-complex catalytic systems, which are
with palladium in the ability to catalyze efficiently many useful
processes, such as various oxidation, reduction, isomerization, car-
bonylation, and coupling reactions, aromatic nucleophilic substitu-
tion, cyclizations, cycloadditions, and others. In fact, various
hydride complexes of palladium have been proposed as key inter-
mediates in diverse Pd catalyzed reactions described in hundreds
of experimental papers and several specialized monographs [28–
30]. Obviously, the synthesis of palladium hydrides and investiga-
tion of their chemical properties represent a special challenge in
organometallic chemistry and catalysis.
Vedernikov et al. [31] briefly communicated their striking
observations of the oxidative addition of various nonactivated, ali-
phatic and aromatic C–H bonds to [(Ph3P)2PdX2] (X: Cl, Br, I) under
exceedingly mild conditions (20–130 °C) (Scheme 2). The process
is obviously of exceptional interest.
In a few cases (R: Cy, X, Br, I) the organopalladium(IV) hydrides
were isolated in admixtures with the starting Pd(II) complexes.
Homogeneous Pd(IV) hydride complexes were not described.
We have prepared previously b-diimine palladium complexes
by treatment of neutral b-iminoamine ligands with the zerovalent
complex Pd(dba)2 in the presence of the methallyloxyphosphoni-
um salt [32–35].
shown to be very effective catalysts in
a-olefin and polar olefin
polymerization, for example, nickel-based systems [11,12].
Recently b-ketoamine ligands have drawn interest. In their
deprotonated form they can be viewed as another potential iso-
electronic alternative to cyclopentadienyl anion owing to their
chelating ability, planar skeleton and resonance driven high acid-
ity. Although complexes incorporating anionic ligands of this type
have been reported [13–19], examples in which the ligand is
bound as a neutral donor appear to be rare [15,19,20–27].
Two coordination modes were described in the literature for the
b-ketiminate (Scheme 1).
Mode A was adopted for most of the described complexes.
Mode B was recently described [26], the essential feature of this
type is that the ligand in a binuclear complex is both chelating
and bridging.
For the neutral b-ketoamine, only one bonding mode was de-
scribed (mode C).
On the other hand, hydride complexes of transition metals rep-
resent a unique class of compounds which play an exceedingly
important role in various fields of chemistry.
To the best of our knowledge, however, the reaction of
(CH3CN)2PdCl2 with neutral b-ketoamine has not yet been
reported.
As a continuation of our study [32–35], we have examined this
reaction with the hope that new complexes incorporating this li-
gand as a b-ketoimine tautomer will be prepared.
* Corresponding author. Tel.: +216 73296030; fax: +216 73500278.
E-mail address: najouahaj@yahoo.fr (N.B.M. Elmkacher).
0277-5387/$ - see front matter Ó 2010 Elsevier Ltd. All rights reserved.
doi:10.1016/j.poly.2010.02.016

N.B.M. Elmkacher et al. / Polyhedron 29 (2010) 1692–1696
1693
We note that there is no signal between 9 and 14 ppm corre-
sponding to the proton of the amine function (N–H). The protons
of the methyl group (CH3–CN) appear between 2.09 and 2.58 ppm.
The presence of the hydride was confirmed by the presence of
the signal at ꢀ18 ppm which appears as a singlet.
The 13C NMR spectra of b-ketoamines present a signal charac-
teristic of the sp2 carbon of the ketone function between 188.46
and 188.95 ppm whereas sp3 carbon of the amine function appears
around 163 ppm. Vinylic carbon appears between 92.25 and
94.91 ppm.
Ar
N
M
Ar
O
N
O
Ar
R1
R2
Ar
N
R1
M'
NH
M'
O
N
O
Ar
M
O
M
O
M
N
R2
The 13C NMR spectra of the complexes present some character-
istics, there is no signal around 93 ppm which is characteristic of
the vinylic carbon and all the spectra present a resonance around
32 ppm. The imine carbon shows signals between 182.64 and
186.01 ppm. The carbonyl shows signals between 197.98 and
198.77.
Ar
A
C
B
Scheme 1. Coordination modes for the b-ketiminate ligand.
The IR spectrum of compounds 6–9 indicated a shift in the C@O
stretching frequency (1747, 1759, 1773, 1745) relative to the
respectively corresponding stretching frequency in the free ligands
1–4 (1665, 1598, 1658, 1620).
X-ray single-crystal analysis reveals that compound 9 exhibits
some interesting features.
Scheme 2. Oxidative addition of C–H bonds to [(Ph3P)2PdX2].
Suitable dark red single crystals of 9 were obtained by crystal-
lization from CH2Cl2/n-hexane. Complex 9 crystallizes in the
monoclinic unit cell P21/c group (Table 1).
In this paper we describe a one-pot synthesis of new hydride
complexes of palladium(IV) supported by b-ketoimine ligands.
An ORTEP-plot shown in Fig. 1 confirms the identity of complex
9 (Fig. 1).
2. Results and discussion
The complex has an unusual structure, the central carbon atom
of the b-ketoimine ligand is r-bound to a PdCl2 fragment. The Pd–
These compounds [(PhCO)CH(CH3CNAr)]Pd(H)(Cl)2 which are
isolated as stable solids, can be easily obtained in high yields by
the reaction of the compound Pd(CH3CN)2(Cl)2 5 in methylene
chloride in the presence of a b-ketoamine ligand (Scheme 3).
The new complexes 6–9 which are soluble in methylene chlo-
ride gave satisfactory analysis and were characterized by 1H, 13C
{1H} NMR and IR spectroscopy.
C(2) bond length of 2.104(7) Å is in agreement with the known va-
lue in the literature for b-diimine related complexes [36].
The palladium atom is in a distorted square planar coordina-
tion environment though the hydride was not clearly found in
the differential Fourier map. Two coordination sites are occupied
by chloride atoms (Cl1 and Cl2), the other two sites are defined by
the central C atom of the b-ketimine ligand and the hydride
ligand. We note that this distortion is illustrated by C(2)–
Pd–Cl (2) and C (2)–Pd–Cl(1) angles of 89.5(2)° and 93.2(2)°
respectively.
The Pd–Cl(2) bond length of 2.278(2) Å is typical of Pd–Cl dis-
tance [37]. The Pd–Cl(1) distance of 2.321(2) Å is indicative of a
bridged chloride ligand (Fig. 2). Consequently the complex is a
dinuclear compound.
The bond distances within the ligand are consistent with the
localized b-ketoimine structure. Selected bond lengths and angles
are listed in Tables 2 and 3.
NMR data for b-ketoamine ligands (1–4) are consistent with the
hydrogen-bridged b-ketoamine.
All 1H NMR spectra of ligands present a broad signal, which cor-
responds to the protons of the amine function (N–H). The chemical
shift of this proton appears between 12.37 and 12.84 ppm. It is
generally very sensitive to concentration, solvent nature and tem-
perature. The protons of the methyl carried by the amino group ap-
pear between 1.68 and 2.41 ppm. The vinylic proton appears in the
form of singlet between 5.82 and 5.94 ppm.
However the 1H NMR spectra of these complexes (6–9) show a
resonance signal around 5.70 ppm which corresponds to the pro-
ton of the central carbon, Thus this resonance is located, respec-
tively, at 5.76, 5.75, 5.67 and 5.66 ppm.
The N–C(1) and O–C(3) bond lengths are typical of double
bonds (1.304(9) Å and 1.226(8) Å respectively).
1
Ar
N
CH3
Ar
N
H
CH3
2
Cl
Cl
H
Pd
H
O
N
CH2Cl2
3
(CH3CN)2PdCl2
Pd
+
4
O
H
H
O
5
H3C
Ar
6-9
1-4
(6) Ar = C6H5
(7) Ar = 2-CH3O-C6H4
(8) Ar = 2,4,6-(CH3)3-C6H2
(9) Ar = 2,6-(iPr)2-C6H3
Scheme 3. Synthesis of [(PhCO)CH(CH3CNAr)Pd(H)(Cl)2]2 complexes.

1694
N.B.M. Elmkacher et al. / Polyhedron 29 (2010) 1692–1696
Table 1
3. Conclusion
Crystallographic data and structure refinement for 9.
Empirical formula
Formula weight
C44H54Cl4N2O2Pd2
We have described a convenient synthetic procedure for the
preparation of the new neutral hydride palladium(IV) complexes
supported by b-ketimine ligand. The reported results are of partic-
ular interest as they contribute to shed light on the one step syn-
thesis of the homogeneous Pd(IV) hydride complexes.
997.5
Temperature (K)
Wavelength (Å)
Crystal system
Space group
293(2)
0.71073
Monoclinic
P21/c
Unit cell dimensions
4. Experimental
a (Å)
b (Å)
c (Å)
9.887(2)
14.738(8)
15.583(4)
90.00
4.1. General
a
(°)
b (°)
100.88(5)
90.00
2229.9(14)
4
1.486
1.083
All manipulations were carried out under an atmosphere of dry
argon using standard Schlenk techniques.
c
(°)
Volume (Å3)
Methylene chloride and hexane were distilled over P2O5. Ani-
line, 2-methoxyaniline, 2,4,6-trimethylaniline and 2,6-diisopropyl-
aniline were distilled from potassium hydroxide prior to use.
Pd(CH3CN)2Cl2 [38] and b-ketoamine ligands [34] were prepared
according to literature methods. All other reagents were obtained
from standard commercial vendors and used as received. NMR
spectra were recorded on a Bruker AC-300 spectrometer. H and C
chemical shifts are given in ppm and referenced to the residual sol-
vent resonance relative to TMS. Infrared spectra were recorded on
a Bruker Victor 22 (Golden Gate Technique).
Z
Calculated density (g cmꢀ3
)
Absorption coefficient (mmꢀ1
F(0 0 0)
)
1016
Crystal size (mm3)
0.11 ꢁ 0.28 ꢁ 0.28
Theta range for data collection
2.10°–24.96°
Limiting indices
ꢀ1 6 h 6 11, ꢀ1 6 k 6 17,
ꢀ18 6 l 6 18
Reflections collected/unique
Completeness to theta = 24.96
Absorption correction
Maximum and minimum transmission
Refinement method
Data/restraints/parameters
Goodness-of-fit (GOF) on F2
5041/3919 [R(int) = 0.0944]
100%
psi-scan
0.8896 and 0.9964
Full-matrix least-squares on F2
3919/0/253
4.2. General procedure for the preparation of b-ketoamines
1.022
Final R indices [I > 2
r
(I)]
R1 = 0.0566, wR2 = 0.1284
R1 = 0.1108, wR2 = 0.1528
1.310 and ꢀ0.774
The b-ketoamines were prepared by adding 50 mol% excess of
the appropriate primary amine directly to the benzoylacetone.
The mixture was heated at 100 °C for several hours in the presence
of calcium sulfate. The products were purified by crystallization.
R indices (all data)
Largest difference peak and hole e Åꢀ3
P
P
R1
¼
wR2
ðjjF0j ꢀ jFcjjÞ= jF0j.
h
i
h
i
1=2
P
P
2
2
2
¼
wðF20 ꢀ F2c Þ = ðF20Þ
; where w ¼ 1= r2ðF20Þ þ ð0:17PÞ ; where P ¼
ðF20 þ 2F2c Þ=3.
4.2.1. 3-N-(phenylamino)-1-phenylbut-2-en-1-one (1)
Following the general procedure, from aniline (55 mmol, 5 mL)
and benzoylacetone (55 mmol, 8.89 g) was obtained 12.47 g of 1 as
a yellow solid after crystallization from hexane. Yield = 83%. m.p.
(°C): 111–112. IR (Golden Gate):
m , mN–H =
C@O = 1665 cmꢀ1
3360 cmꢀ1 1H NMR (300 MHz, CDCl3, 25 °C, d [ppm]): 2.41 (s,
.
3H, (NH)C–CH3); 5.91 (s, 1H, CHCO(Ph)); 7.17–7.95 (m, 10H,
Harom); 12.84 (s, 1H, H–N). 13C NMR (75.5 MHz, CDCl3, 25 °C, d
[ppm]): 20.52 (CH3–CN); 94.36 (CHCO(Ph)); 124.81–140.07
(Carom); 162.32 (C–N); 188.71 (C@O).
4.2.2. 3-N-(2-methoxyphenylamino)-1-phenylbut-2-en-1-one (2)
Following the general procedure, from 2-methoxyphenylamine
(44 mmol, 5 mL) and benzoylacetone (44 mol, 7.19 g) was obtained
10.82 g of 2 as a yellow solid after crystallization from hexane.
Yield = 92%. m.p. (°C): 142–144. IR (Golden Gate): mC@O
=
1598 cmꢀ1 N–H = 3411 cmꢀ1 1H NMR (300 MHz, CDCl3, 25 °C, d
,
m
.
[ppm]): 2.06 (s, 3H, (NH)C–CH3); 3.81 (s, 3H, 2-OCH3–C6H4); 5.83
(s, 1H, CHCO(Ph)); 6.84–7.88 (m, 9H, Harom); 12.84 (s, 1H, H–N).
13C NMR (75.5 MHz, CDCl3, 25 °C,
d [ppm]): 20.95 (CH3–
CN);56.20 (2-OCH3–C6H4); 94.91 (CHCO(Ph)); 111.73–153.38
(Carom); 162.81 (C–N); 188.95 (C@O).
4.2.3. 3-N-(2,4,6-trimethylphenylamino)-1-phenylbut-2-en-1-one (3)
Following the general procedure, from 2,4,6-trimethylaniline
(35 mmol; 5 mL) and benzoylacetone (35 mmol; 5.67 g) was ob-
tained 7.6 g of 3 as a yellow solid. Yield = 78%. m.p. (°C): 113–
Fig. 1. Perspective ORTEP diagram of complex 9. Thermal ellipsoids are at 30%
probability. Hydrogen atoms are omitted for clarity.
115. IR (Golden Gate):
m , m .
C@O = 1658 cmꢀ1 N–H = 3395 cmꢀ1 1H
NMR (300 MHz, CDCl3, 25 °C, d [ppm]): 1.68 (s, 3H, (NH)C–CH3);
2.10 (s, 6H, 2,6-(CH3)2–C6H2); 2.20 (s, 3H, 4-CH3–C6H2); 5.82 (s,
1H, CHCO(Ph)); 6.59–7.87 (m, 7H, Harom); 12.37 (s, 1H, N–H). 13C
NMR (75.5 MHz, CDCl3, 25 °C, d [ppm]): 18.61 (4-CH3–C6H2);
The b-ketoimine ligand core is almost planar, thus the atoms O,
C(3), C(2), N are situated in the same plane, whereas the atom C(1)
is 0.09 Å out of this plane.

N.B.M. Elmkacher et al. / Polyhedron 29 (2010) 1692–1696
1695
Fig. 2. Perspective ORTEP diagram of complex 9. Thermal ellipsoids are at 30% probability. Aryl ring are omitted for clarity.
(3 ꢁ 15 cm3) and dried in vacuum. The solid was crystallized from
methylene chloride/n-hexane solution. Yields and spectral data of
compounds 6–9 are reported below.
Table 2
Selected interatomic distances (Å).
Pd–C(2)
Pd–Cl(1)
Pd–Cl(2)
N–C(1)
2.104(7)
2.321(2)
2.278(2)
1.304(9)
1.226(8)
C(1)–C(2)
C(2)–C(3)
C(1)–C(4)
C(3)–C(5)
N–C(11)
1.457(9)
1.495(10)
1.492(10)
1.497(9)
1.459(8)
4.3.1. [(PhCO)CH(CH3CN(C6H5)]Pd(H)(Cl)2(6)
O–C(3)
Following the general procedure, from [(PhCO)CH(CH3CN-
(H)(C6H5)], (109 mg, 0.457 mmol) and Pd(CH3CN)2(Cl)2 (0.1 g,
0.457 mmol) was obtained 0.175 g of 6 as a dark red solid after
crystallization from a mixture (CH2Cl2/n-hexane: 1/1).
Table 3
Selected angles (°) for 9.
Yield 92%. IR (Golden Gate):
m , mC@O =
C@N = 1620 cmꢀ1
1747 cmꢀ1
.
1H NMR (300 MHz, CDCl3, 25 °C, d [ppm]): ꢀ18 (s,
N–C(1)–C(4)
N–C(1)–C(2)
C(1)–C(2)–C(3)
O–C(3)–C(2)
O–C(3)–C(5)
119.8(6)
C(1)–N–C(11)
C(2)–Pd–Cl(2)
C(2)–Pd–Cl(1)
Cl(2)–Pd–Cl(1)
122.4(6)
89.5(2)
93.2(2)
1H, hydride), 2.58 (s, 3H, CH3–CN), 5.76 (s, 1H, HC–Pd), 7.17–8.43
(m, 10H, Harom). 13C NMR (75.5 MHz, CDCl3, 25 °C, d [ppm]):
23.29 and 23.36 (CH3–CN), 33.02 and 33.28 (C–Pd), 125.20–
137.51 (Carom), 182.64 and 182.86 (C@N), 198.59 and 198.77
(C@O).
122.5(7)
120.2(6)
121.8(6)
120.7(7)
176.11(8)
19.86 (2,6-(CH3)2–C6H2); 21.36 (CH3–CN); 92.66 (CHCO(Ph));
122.22–160.26 (Carom); 165.48 (C–N); 188.82 (C@O).
4.3.2. [(PhCO)CH(CH3CN(2–CH3O–C6H4)]Pd(H)(Cl)2 (7)
Following the general procedure, from [(PhCO)CH(CH3CN(H)(2-
CH3O–C6H4)], (0.122 mg, 0.457 mmol) and Pd(CH3CN)2(Cl)2 (0.1 g,
0.457 mmol) was obtained 0.193 g of 7 as a dark red solid after
crystallization from a mixture (CH2Cl2/n-hexane: 1/1).
4.2.4. 3-N-(2,6-diisopropylphenylamino)-1-phenylbut-2-en-1-one (4)
Following the general procedure, from 2,6-diisopropylaniline
(26 mmol; 5 mL), benzoylacetone (26 mmol; 4.9 g) was obtained
8.02 g of 4 as a yellow solid after crystallization from hexane.
Yield 95%. IR (Golden Gate):
m , mC@O =
C@N = 1612 cmꢀ1
1759 cmꢀ1
.
1H NMR(300 MHz, CDCl3, 25 °C, d [ppm]): ꢀ18 (s, 1H,
Yield = 86%. m.p. (°C): 132–133. IR (Golden Gate): mC@O
=
hydride), 2.56 (s, 3H, CH3–CN), 3.87 (s, 3H, CH3O), 5.75 (s, 1H,
HC–Pd), 7.02–8.46 (m, 9H, Harom). 13C NMR (75.5 MHz, CDCl3,
25 °C, d [ppm]): 22.76 (CH3–CN), 31.99 (C–Pd), 56.09 (CH3O),
121.18–152.68 (Carom), 183.04 (C@N), 198.21 (C@O).
1620 cmꢀ1 N–H = 3386 cmꢀ1 1H NMR (300 MHz, CDCl3, 25 °C, d
,
m
.
[ppm]): 1.17 (d, 6H, H3C–iPr, J = 6.9 Hz); 1.23 (d, 6H, H3C–iPr,
J = 6.9 Hz); 1.79 (s, 3H, (NH)C–CH3); 3.10 (sept, 2H, HC–iPr,
J = 6.6 Hz); 5.94 (s, 1H, CHCO(Ph)); 7.19–7.97 (m, 8H, Harom);
12.64 (s, 1H, H–N). 13C NMR (75.5 MHz, CDCl3, 25 °C, d [ppm]):
19.93 (CH3–CN); 22.77 (CH3–iPr); 24.69 (CH3–iPr); 28.59 (CH–
iPr); 92.39 (CHCO(Ph)); 123.63–146.24 (Carom); 165.23 (C–N);
188.46 (C@O).
4.3.3. [(PhCO)CH(CH3CN(2,4,6-(CH3)3-C6H2)]Pd(H)(Cl)2 (8)
Following the general procedure, from [(PhCO)CH(CH3-
CN(H)(2,4,6-(CH3)3–C6H2)], (0.128 g, 0.457 mmol) and Pd(CH3CN)2-
(Cl)2 (0.1 g, 0.457 mmol) was obtained 0.191 g of 8 as a dark red so-
lid after crystallization from a mixture (CH2Cl2/n-hexane: 1/1).
4.3. General procedure for the preparation of
[(PhCO)CH(CH3CNAr)]Pd(H)(Cl)2 complexes
Yield 91%. IR (Golden Gate):
m , mC@O =
C@N = 1601 cmꢀ1
1773 cmꢀ1
.
1H NMR (300 MHz, CD2Cl2, 25 °C, d [ppm]): ꢀ18 (s,
In an inert atmosphere, Pd(CH3CN)2(Cl)2 complex (1 equiv.) was
dissolved in 20 cm3 anhydrous CH2Cl2 and b-ketoamine ligands
were added (1 equiv.). The dark red solution was stirred at room
temperature for 24 h. The supernatant was separated by filtration
through a celite filter, and the solvent was removed under vacuum
to afford the oil compound. This was washed with hexane
1H, hydride), 2.09 (m, 3H, CH3–CN), 2.31–2.36 (m, 6H, CH3–
C6H2), 2.70 (m, 3H, CH3–C6H2), 5.67 (s, 1H, HC–Pd), 6.99–8.46 (m,
7H, Harom). 13C NMR (75.5 MHz, CD2Cl2, 25 °C, d [ppm]): 17.90,
19.38 and 20.82 (CH3–C6H2), 21.73 (CH3–CN), 31.73 and 31.94
(C–Pd), 128.91–139.82 (Carom), 185.76 and 186.01 (C@N), 198.12
and 198.29 (C@O).

1696
N.B.M. Elmkacher et al. / Polyhedron 29 (2010) 1692–1696
[4] A. Bader, E. Lindner, Coord. Chem. Rev. 108 (1991) 27.
[5] W. Keim, H. Maas, S. Mecking, Z. Naturforsch. 50b (1995) 430.
[6] A. HeBler, J. Fischer, S. Kucken, O. Stelzer, Chem. Ber. 127 (1994) 481.
[7] H. Hoberg, A. Ballesteros, A. Sigan, J. Organomet. Chem. C19 (1991) 403.
[8] H.J. Haupt, U. Ortmann, Z. Anorg. Allg. Chem. 619 (1993) 1209.
[9] G.P.C.M. Dekker, A. Buijs, C.J. Elsevier, K. Vrieze, P.W.N.M. van Leeuwen, W.J.J.
Smeets, A.L. Spek, Y.F. Wang, C.H. Stam, Organometallics 11 (1992) 1937.
[10] H. Jin, K.J. Cavell, J. Chem. Sot., Dalton Trans. (1994) 415.
[11] M. Peukert, W. Keim, Organometallics 2 (1983) 594.
[12] B. Reuben, H. Wittcoff, J. Chem. Educ. 65 (1988) 605.
[13] G.W. Everett Jr., R.H. Holm, J. Am. Chem. Soc. 87 (1965) 2117.
[14] G.W. Everett Jr., R.H. Holm, J. Am. Chem. Soc. 88 (1966) 2442.
[15] D. Jones, A. Roberts, K. Cavell, W. Keim, U. Englert, B.W. Skelton, A.H. White, J.
Chem. Soc., Dalton. Trans. (1998) 255.
4.3.4. [(PhCO)CH(CH3CN(2,6-(iPr)2–C6H3)]Pd(H)(Cl)2 (9)
Following the general procedure, from [(PhCO)CH(CH3CN(H)-
(2,6-(iPr)2–C6H3)], (0.147 g, 0.457 mmol) and Pd(CH3CN)2(Cl)2
(0.1 g, 0.457 mmol) was obtained 0.215 g of 9 as a dark red solid
after crystallization from a mixture (CH2Cl2/n-hexane: 1/1).
Yield 94%. IR (Golden Gate):
m , mC@O =
C@N = 1583 cmꢀ1
1745 cmꢀ1
.
1H NMR (300 MHz, CD2Cl2, 25 °C, d [ppm]): ꢀ18 (s,
1H, hydride), 1.19–1.50 (m, 12H, CH3–iPr), 2.31 (s, 3H, CH3–CN),
2.71 (sl, 1H, CH–iPr), 4.05 (sl, 1H, CH–iPr), 5.66 (s, 1H, HC–Pd),
7.28–8.45 (m, 8H, Harom). 13C NMR (75.5 MHz, CD2Cl2, 25 °C, d
[ppm]): 22.33 and 22.61 (CH3–CN), 23.05, 23.34, 23.73, 24.90 and
25.57 (CH3–iPr), 28.99 (CH–iPr), 31.65 and 32.83 (C–Pd), 124.09–
144.91 (Carom), 185.89 (C@N), 197.98 (C@O).
[16] S. Doherty, R.J. Errington, N. Housley, J. Ridland, W. Clegg, M.R.J. Elsegood,
Organometallics 18 (1999) 1018.
[17] Y.L. Tung, W.C. Tseng, C.Y. Lee, P.F. Hsu, Y. Chi, S.M. Peng, G.H. Lee,
Organometallics 18 (1999) 864.
[18] J. Scholz, G.A. Hadi, K.H. Thiele, H. Gorls, R. Weimann, H. Schumann, J. Sieler, J.
Organomet. Chem. 626 (2001) 243.
4.4. X-ray crystallographic study
[19] J. Kim, J.W. Hwang, Y. Kim, M.H. Lee, Y. Han, Y. Do, J. Organomet. Chem. 620
(2001) 1.
[20] A. Panda, M. Stender, R.J. Wright, M.M. Olmstead, P. Klavins, P.P. Power, Inorg.
Chem. 41 (2002) 3909.
The X-ray crystallographic study of complex 10 was carried out
on a CAD4 Enraf–Nonius diffractometer (Mo Ka). Data were col-
lected at 293 K in the range 2–25° and this gave a total of 5041
reflections, yielding 3919 independent values (Rint = 0.0944). The
structure was solved by direct method and difference Fourier tech-
niques and were refined by full-matrix least-squares analysis.
Refinements were based on F2 and were carried out using all the
data (SHELXL-97). All of the non-hydrogen atoms were refined aniso-
tropically. The set of physical and crystallographic characteristics
as well as the experimental conditions are listed in Table 1.
[21] X. He, Y. Yao, X. Luo, J. Zhang, Y. Liu, L. Zhang, Q. Wu, Organometallics 22
(2003) 4952.
[22] X.F. Li, K. Dai, W.P. Ye, L. Pan, Y.S. Li, Organometallics 23 (2004) 1223.
[23] L.M. Tang, T. Hu, Y.J. Bo, Y.S. Li, N.H. Hu, J. Organomet. Chem. 690 (2005) 3125.
[24] L. Zhang, M. Brookhart, P.S. White, Organometallics 25 (2006) 1868.
[25] H.Y. Wang, J. Zhang, X. Meng, G.X. Jin, J. Organomet. Chem. 691 (2006) 1275.
[26] S.H. Hsu, C.Y. Li, Y.W. Chiu, M.C. Chiu, Y.L. Lien, P.C. Kuo, H.M. Lee, J.H. Huang,
C.P. Cheng, J. Organomet. Chem. 692 (2007) 5421.
[27] W.Y. Lee, H.H. Hsieh, C.C. Hsieh, H.M. Lee, G.H. Lee, J.H. Huang, T.C. Wu, S.H.
Chuang, J. Organomet. Chem. 692 (2007) 1131.
[28] P.M. Maitlis, The Organic Chemistry of Palladium, vols. 1 and 2, Academic
Press, New York, 1971.
Supplementary data
[29] J. Tsuji, Organic Synthesis with Palladium Compounds, Springer-Verlag, New
York, 1980.
[30] R.F. Heck, Palladium Reagents in Organic Synthesis, Academic Press, New York,
1985.
[31] A.N. Vedernikov, A.I. Kuramshin, B.N. Solomonov, J. Chem. Soc., Chem.
Commun. 1994, 121.
[32] K. Landolsi, M. Rzaigui, F. Bouachir, Tetrahedron Lett. 43 (2002) 9463.
[33] K. Landolsi, P. Richard, F. Bouachir, J. Organomet. Chem. 690 (2005) 513.
[34] K. Landolsi, N. Belhadj Mbarek Elmkacher, T. Guerfel, F. Bouachir, C. R. Chimie
11 (2008) 752.
CCDC 683393 contains the supplementary crystallographic data
for this paper. These data can be obtained free of charge via http://
www.ccdc.cam.ac.uk/conts/retrieving.html, or from the Cambridge
Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ,
UK; fax: (+44) 1223-336-033; or e-mail: deposit@ccdc.cam.ac.uk.
[35] N. Belhaj Mbarek Elmkacher, T. Guerfel, I. Tkatchenko, F. Bouachir, Polyhedron
27 (2008) 893.
References
[36] J. Feldman, S.J. McLain, A. Parthasarathy, W.J. Marshall, J.C. Calabrese, S.D.
Arthur, Organometallics 16 (1997) 1514.
[37] D.N. Coventry, A.S. Batsanov, A.E. Goeta, J.A.K. Howard, T.B. Marder,
Polyhedron 23 (2004) 2789.
[1] J.C. Jeffrey, T.B. Rauchfuss, Inorg. Chem. 18 (1979) 2658.
[2] B. Demerseman, C. Renouard, R. Le Lagadec, M. Gonzalez, P. Crochet, P.H.
Dixneuf, J. Organomet. Chem. 471 (1994) 229.
[3] M.C. Bonnet, F. Dahan, A. Ecke, W. Keim, R.P. Schulz, I. Tkatchenko, J. Chem.
Soc., Chem. Commun. (1994) 615.
[38] F.R. Hartley, S.G. Murray, C.A. McAuliffe, Inorg. Chem. 18 (1979) 1394.