Substituent effect on cyclopalladation of arylimines

Article abstract of DOI:10.1016/j.jorganchem.2004.03.002

The substituent effect on cyclopalladation of a series of substituted benzylidene-arylamines [(R₂C₆H₃) NCCH₂(ArX_n), where R=H, Me, i-Pr, OH; X_n=H; 3,5-dimethoxyl; 3,5-difloro; 3,5-bis(2,6-dimethoxyphenyl); 4-chloro; 2-bromo; 2,4,6-trimethyl] by palladium(II) chloride under basic conditions was studied. As expected, cyclometallation takes place at the ortho position of the aryl ring resulting in formation of a five-member chelate ring. All metallated products have in chloro-bridged dipalladium [Pd₂Cl₂] structures except the one with R=OMe. A palladium species with mixed bridging ligand [Pd₂(OH)Cl] was isolated due to the hydrogen-bonding interaction through the hydroxy ligand and the methoxy substituents. For the t-butyl substituted arylimine, cyclometallation does not occur because of the steric reason. In the case of R=OH, X_n=2,4,6-trimethyl, the cyclopalladation occurred at the benyzlic position forming a tetrameric palladium species. All the palladium complexes were characterized by both spectral and/or crystal structural analyses.

Full text of DOI:10.1016/j.jorganchem.2004.03.002

Journal of Organometallic Chemistry 689 (2004) 1806–1815
www.elsevier.com/locate/jorganchem
Substituent effect on cyclopalladation of arylimines
*
Chuan-Lin Chen, Yi-Hung Liu, Shie-Ming Peng, Shiuh-Tzung Liu
Department of Chemistry, National Taiwan University, 1, Section 4, Roosevelt Road, Taipei 106, Taiwan, ROC
Received 1 October 2003; accepted 2 March 2004
Abstract
The substituent effect on cyclopalladation of a series of substituted benzylidene-arylamines [(R2C6H3)N@CCH2(ArXn), where
R ¼ H, Me, i-Pr, OH; Xn ¼ H; 3,5-dimethoxyl; 3,5-difloro; 3,5-bis(2,6-dimethoxyphenyl); 4-chloro; 2-bromo; 2,4,6-trimethyl] by
palladium(II) chloride under basic conditions was studied. As expected, cyclometallation takes place at the ortho position of the aryl
ring resulting in formation of a five-member chelate ring. All metallated products have in chloro-bridged dipalladium [Pd2Cl2]
structures except the one with R ¼ OMe. A palladium species with mixed bridging ligand [Pd2(OH)Cl] was isolated due to the
hydrogen-bonding interaction through the hydroxy ligand and the methoxy substituents. For the t-butyl substituted arylimine,
cyclometallation does not occur because of the steric reason. In the case of R ¼ OH, Xn ¼ 2,4,6-trimethyl, the cyclopalladation
occurred at the benyzlic position forming a tetrameric palladium species. All the palladium complexes were characterized by both
spectral and/or crystal structural analyses.
ꢀ 2004 Elsevier B.V. All rights reserved.
Keywords: Cyclopalladation; Arylimine; C–H activation
La
Lb
Lc
Ld
Le
Lf
1. Introduction
Xn = H, R = R' = i-Pr
n = 3, 5-dimethoxyl, R = R' =i-Pr
Xn = 3, 5-difloro, R = R' = i-Pr
X
R'
R
Among the various examples of intramolecular C–H
activation via transition metal complexes, cyclopalla-
dation of benzylidene-arylamine ligands is the one with
extensively studied [1–6]. It is known that such palla-
dation preferentially occurs at the carbon center, which
would tend to form a five-membered ring, and at sp2
hybridized C–H bonds. In terms of the electronic effect,
substituents on both the nitrogen center and the aro-
matic ring affect the rate of metallation [6]. Although
many studies involving cyclopalladation of the substi-
tuted benzylidenearylamines are presented in the litera-
ture [2–6], few are in the investigation of bulky and
donative substituents on both aromatic systems [1c,2a].
Here we report the cyclopalladation reactions of a wide
variety of substituted benzylidene-dialkylarylamines Ln
with (CH3CN)2PdCl2 under basic conditions.
Xn = 3, 5-bis(2,6-dimethoxyphenyl), R = R' = i-Pr
N
X
X
n = 4-chloro, R = R' = i-Pr
n = 2-bromo, R = R' = i-Pr
Lg Xn = 4-methoxy-3, 5-di-t-butyl, R = R' = i-Pr
Lh
Li
X
n = 4-methoxy-3, 5-di-t-butyl, R = R' = Me
Xn
Xn = 2, 4, 6-trimethyl, R = OH, R' = H
2. Results and discussion
2.1. Preparation of ligands
Condensation reaction of aniline derivatives with an
excess of the corresponding substituted bezaldehyde in
methanol provided the desired ligands in good yields
upon chromatography, whereas the aldehydes used for
the preparation of Lx (x ¼ d, i) were prepared accord-
ingly to the literature procedure (see Section 4). Char-
acterizations of this series of compounds were
performed by spectral and elemental analyses. Selected
* Corresponding author. Tel.: +886-2-2366-0352; fax: +886-2-2363-
6359.
E-mail addresses: stliu@ccms.ntu.edu.tw, stliu@ntu.edu.tw (S.-T.
Liu).
0022-328X/$ - see front matter ꢀ 2004 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2004.03.002

C.-L. Chen et al. / Journal of Organometallic Chemistry 689 (2004) 1806–1815
1807
Table 1
Spectral data for ligands La–Li
structure, which is consistent with the related works un-
der the similar conditions reported in the literature [1,2].
Although cis and trans isomers are possible in the chloro-
bridged palladium dimers, complexes 1a, 1c, 1d and 1f
were formed in the trans configuration. Interestingly, a
pair of products cis-1b and trans-1b were obtained when
Lb was used. Both cis-1b and trans-1b were obtained in 1:1
ratio upon the extraction of reaction products with a
mixture of dichloromethane/water. However, only the
trans-1b was yielded when the n-hexane was used as the
extraction solvent. The dipalladium metal center in trans-
1b remains as di-chloro brideged core, but hydroxy and
chloride become the bridging ligands between two metal
center in the cis-1b as confirmed by spectral and crystal-
lographic analyses (see below).
IR mC@N (cmꢀ1
)
13C NMR –C@N–
1H NMR
Ligands
Ho
–HC@N
La
Lb
Lc
Ld
Le
Lf
Lg
Lh
Li
1646
1604
1595
1635
1640
1632
1645
1646
1630
7.90
7.07
7.42
7.88
7.83
8.25
7.79
7.88
7.59
8.20
8.11
8.11
8.23
8.14
8.56
8.09
8.20
9.10
162.0
161.9
159.5
162.5
160.6
161.4
162.7
162.7
157.7
spectral data are summarized in Table 1. Infrared ab-
sorption near 1600 cmꢀ1 is a characteristic stretching
frequency for C@N. In addition, the imine carbon shift
(ꢁ160 ppm) in the 13C NMR is further evidence to
R
R
R
R
1
support the existence of this structure. The H NMR
N
N
chemical shifts appeared in the range of 8–9 ppm are
typical for the imino protons (–HC@N). It is noticed
that a long-range 19F coupling is observed in compound
Lc. Thus the 13C NMR signal of imino-carbon appears
Cl
2
Pd
Xn
Xn
4
as a triplet at 159.6 ppm with JC–F ¼ 3 Hz.
Xn = H, R = isopropyl
Xn = 3, 5-dimethoxyl, R = isopropyl
1a
1b
1c
1d
1e
1f
2.2. Cyclopalladtion
X
X
X
n = 3, 5-difloro, R = isopropyl
n = 3, 5-bis(2,6-dimethoxyphenyl), R = isopropyl
n = 4-chloro, R = isopropyl
To a mixture of (CH3CN)2PdCl2, sodium acetate and
the ligands La–Lf in tetrahydrofuran were stirred at
ambient temperature for 38 h and the desired cyclopal-
ladtion products were isolated as stable solids upon
crystallization (Eq. (1)). All products were characterized
by spectral methods and some of them are further con-
firmed by single-crystal structural analysis. Selected
spectral data of cyclopalladated product with this series
of ligands are summarized in Table 2. In all instances, the
cyclopalladation readily occurs at ortho position of the
benzal ring to form an endo five membered chelate ring
and the products having a chloro-bridged dipalladium
Xn = 2-bromo, R = isopropyl
ð1Þ
Me
O
Me
O
N
Cl
N
N
Pd
Cl
Pd Pd
O
Pd
Cl
N
Br
O
Me
O
H
O
O
NCy
O
O
Me
Me
Me
Me
Me
2
cis-1b
trans-1b
Table 2
Selected spectral data of complexes
OMe
R
OMe
Compound
IRamC@N
1H NMRb
13C NMR
R
R
N
Me
Me
O
O
Cl
O
O
–HC@N–
–HC@N–
Cl
N
Cl
Cl
Pd
R
Pd
Pd
Me
Pd
N
Cl
N
Cl
1a
Cis-1b
1603
1586
1584
1570
1591
1602
1588
1612
1610
1613
1595
7.72
7.56
176.2
176.0
Me
OMe
Trans-1b
Trans-1c
7.66; 7.63
7.70; 7.67
7.61
177.2; 177.0
176.6; 176.4
176.9
OMe
3
3
g R = i-Pr
h R= Me
3h'
1d
1e
1f
3g
3h
3h0
7i
7.70
8.10
175.4
c
9.41
9.24
176.1
176.0
173.8
163.7
Notably, the o-metallation of C–H bond took place
preferentially over the oxidative addition of C–Br bond
in Lf as evidenced by the NMR spectroscopic study. The
chemical shift corresponding to the ortho proton (d 8.25)
in the free ligand Lf disappeared after the reaction with
the appearance of three distinct aromatic resonances in
8.81
8.05
a KBr, cmꢀ1
.
b Coupling constant J in Hz.
c Not determined.

1808
C.-L. Chen et al. / Journal of Organometallic Chemistry 689 (2004) 1806–1815
(Table 2) clearly indicate the coordination of imine to-
ward the metal center. For the palladation products 1a–f
,
the disappearance of the ortho aromatic proton on the
1H NMR spectrum clearly demonstrates that C–H ac-
tivation occurred at that site. For those with isopropyl
Me
N
exo
Pd
Cl
N
Pd
Cl
N
Pd
Cl
1
substitutents, the methyl groups on the H NMR spec-
2
trum appear a doublet in the free ligands, but split into
two sets of doublets upon cyclometallation, which is
presumably due to the hindered rotation of that group.
The dimeric structure of the bridging chloro ligand of
these species as well as the stereochemistry of 1b is fur-
ther confirmed by their single-crystal structure deter-
mination, which is consistent with most of the related
complexes reported [3].
Single crystals of complex 1a were grown by re-crys-
tallization from CH2Cl2/hexane at ambient temperature.
An ORTEP diagram for 1a is shown in Fig. 2. Crys-
tallographic data are summarized in Table 5; selected
bond distances and bond angles are shown in Table 3. In
the complex La ligand is bonded to the di-l-chloro-
bridge unit through the nitrogen and an aromatic car-
bon atom providing a five-membered chelate ring.
Structural data for 1a show that the coordination ge-
ometry about the palladium atom is slightly distorted
from square plane with the two imino ligands in trans
OMe
2
2
4
5
6h
Fig. 1. C–H activation at benzylic position.
1H NMR of the complex, indicating that the C–H ac-
tivation at aromatic ring has occurred. This outcome is
quite similar to that reported by Vila et al. [7] in the
metallation of 2.
Reaction of bulky ligands Lg and Lh with
(CH3CN)2PdCl2 in the presence of sodium acetate pro-
vides a simple substitution product 3g–h without the for-
mation of any cyclometallated product. The tertiary butyl
group at meta position of benzylimine readily hindered
the C–H activation at ortho position. By contrast with the
findings that the cyclopalladation occurred with methyl-
quinoline or methylaniline to form 4 and 5, respectively
[8], we noticed that the metallation did not occur at ben-
zylic position of Lh to provide 6h, presumably due to the
energically unfavorable five-exo chelate ring (Fig. 1).
Most of the cyclopalladated complexes in this work were
isolated as chloro-bridging dinuclear species, but complex
3h was in the form of both aceto- and chloro-bridged ones.
However, there were no products with mixed bridged li-
gands formed from this reaction.
O
N
Pd
4
7i
Fig. 2. ORTEP plot of 1a.
In case of ligand Li, cyclopalladation took place at
benzylic position with the coordination phenolate-oxy-
gen toward the metal center as evidenced by its 1H
NMR. The appearance of two sets of doublets at 3.40
and 2.52 with integration of 1H each clearly indicated
the formation Pd–C via C–H activation. This C–H ac-
tivation is favored by the formation of a six-endo chelate
ring unlike the imine Lh. Instead of di-palladium com-
plex, the cyclopalladated product 7i forms a tetra-nu-
clear species via the coordination of an oxygen donor as
evidenced by its crystal structure.
Table 3
ꢀ
Selected bond distances (A) and bond angles (ꢁ)
Complex
1a
trans-1b
1d
Pd(1)–N(1)
Pd(1)–C(1)
C(7)–N(1)
2.022(1)
1.965(2)
1.279(2)
2.3255(5)
2.4506(5)
2.3255(5)
3.457
2.021(2)
2.042(2)
2.016(3)
1.278(4)
2.3285(8)
2.4333(8)
2.3285(8)
3.545
2.007(3)
1.286(3)
2.3248(7)
2.4208(7)
2.3248(7)
3.503
Pd(1)–Cl(1)
Pd(1)–Cl(1A)
Pd(1A)–Cl(1A)
Pd(1)ꢂ ꢂ ꢂPd(1A)
N(1)–Pd(1)–C(1)
N(1)–Pd(1)–Cl(1)
N(1)–Pd(1)–Cl(1A)
C(1)–Pd(1)–Cl(1)
Cl(1)–Pd(1)–Cl(1A)
81.13(7)
176.10(4)
96.59(4)
94.98(5)
87.31(2)
80.91(9)
177.47(6)
94.21(5)
99.92(7)
84.88(2)
81.6(1)
177.51(7)
94.16(7)
100.50(8)
83.79(3)
2.3. Structural characterization
Both the red-shift of stretching frequency on C@N
and the positive coordination shift of imine-proton

C.-L. Chen et al. / Journal of Organometallic Chemistry 689 (2004) 1806–1815
1809
arrangement with respect to the Pd–Pd axis, which is
essentially similar to those of the cyclopalladated species
with a five-member chelate ring [9]. A long distance
ring remains in planar geometry with the palladium
metal center slightly off the plane. Similarly, crystal
structure of 1d (Fig. 5) was also determined. Selected
bond distances and bond angles are summarized in
Table 3. This structure is essentially comparable to those
discussed in 1a and trans-1b, except the angle of C(1)–
Pd(1)–Cl(1) [100.50(8)ꢁ]. This large deviation may be
related to render the steric relief due to the isopropyl
and aryl groups.
ꢀ
between two palladium atoms (3.457 A) excludes the
possibility of metal–metal bonding. The two diisopro-
pylphenyl rings are nearly orthogonal with respect to the
chelate ring.
The structures of both trans-1b and cis-1b were de-
termined by their X-ray diffraction. Single crystals of
trans-1b were obtained by slow solvent evaporation from
hexane at room temperature, but crystals of cis-1b were
grown from co-crystallization of trans-1b and cis-1b
from a solution of CH2Cl2 and water. The ORTEP plots
of trans-1b and cis-1b are illustrated in Figs. 3 and 4,
with crystallographic information summarized in Table
5. Selected bond lengths and angles of trans-1b are col-
lected in Table 3 as well. The structural feature around
the Pd2Cl2 core of trans-1b is essentially similar to that
of 1a. The geometry at palladium in trans-1b is distorted
square planar with the bite angle (N–Pd–C) at the metal
[80.91(9)ꢁ]. The distances of N–C(7) lie between 1.286(3)
The X-ray diffraction analysis on cis-1b shows a un-
ique structure in which one of the bridging ligands is OH
group. This observation is quite different from the other
palladium dimmers. There are few dipalladium species
with [Pd2Cl(OH)] core center appeared in the literature
and only one crystal structure among them has been
reported [10]. The relevant bond lengths and angles in
cis-1b lie in the normal range and the coordination ge-
ometry is similar to trans-1b; however, the conformation
of the [Pd2Cl(OH)] core is different from that of
[Pd2Cl2]. The dihedral angle for two planes defined by
Pd(1)–O(1)–Pd(2) and Pd(1)–Cl(1)–Pd(2) is 22.8(2)ꢁ,
clearly demonstrates a butterfly shape for the core of
[Pd2Cl(OH)]. The hydrogen of OH group is confirmed
ꢀ
A, which is typical for C@N bonds. The C,N chelate
1
by both calculation and H NMR shift (d 2.81 ppm).
The distances of H(1)ꢂ ꢂ ꢂO(3) and H(1)ꢂ ꢂ ꢂO(4) are
ꢀ
2.43(1) and 2.26(4) A, respectively, which are within the
range of hydrogen bonds. Presumably, the cis-arrange-
ment of ligands in this complex is stabilized through the
hydrogen bonds of type O–Hꢂ ꢂ ꢂO–C, i.e. the methoxy
groups on the aromatic ring might play the role on the
construction of the hydroxy bridging ligand. This also
explains why the other dipalladium complexes only exist
in the core of [Pd2Cl2]. The Pdꢂ ꢂ ꢂPd distance of cis-1b is
ꢀ
3.2798(6) A, indicating there is no metal–metal bond
between them.
The signal at 1.97 ppm on 1H NMR corresponding to
the methyl group of acetate reveals the coordination of
that ligand to the metal center in the complexes 3g and 3h.
Nevertheless, the detail structural information of 3g is
obtained by its X-ray single-crystal analysis (Fig. 6). The
diffraction study shows the acetato-bridged dipalladium
Fig. 3. Molecular structure of trans-1b.
ꢀ
Fig. 4. ORTEP plot of cis-1b. Pd(1)–C(1) 1.991(5) A, Pd(1)–N(1)
ꢀ
ꢀ
2.011(4) A, Pd(1)–O(1) 2.078(4) A, Pd(1)–Cl(1) 2.432(2) A, Pd(2)–
ꢀ
ꢀ
C(22) 1.991(5) A, Pd(2)–N(2) 2.019(4) A, Pd(2)–O(1) 2.062(4) A,
ꢀ
ꢀ
ꢀ
ꢀ
Pd(2)–Cl(1) 2.421(2) A, Pdꢂ ꢂ ꢂPd 3.2798(6) A, C(1)–Pd(1)–N(1)
80.6(2)ꢁ, C(1)–Pd(1)–O(1) 99.8(2)ꢁ, N(1)–Pd(1)–O(1) 177.7(2)ꢁ, C(22)–
Pd(2)–Cl(1) 178.7(2)ꢁ, N(2)–Pd(2)–O(1) 173.3(2)ꢁ.
Fig. 5. ORTEP plot of 1d.

1810
C.-L. Chen et al. / Journal of Organometallic Chemistry 689 (2004) 1806–1815
Table 4
ꢀ
Bond distances (A) and bond angles (ꢁ) of complex 7i
Pd(1)–N(1)
Pd(2)–N(2)
Pd(3)–N(3)
Pd(4)–N(4)
Pd(1)–O(1)
Pd(2)–O(2)
Pd(3)–O(3)
Pd(4)–O(4)
Pd(1)–O(4)
Pd(2)–O(3)
Pd(3)–O(1)
Pd(4)–O(2)
Pd(1)–C(14)
Pd(2)–C(30)
Pd(3)–C(46)
Pd(4)–O(62)
1.965(4)
1.969(4)
1.984(4)
1.977(4)
2.130(3)
2.117(3)
2.120(3)
2.123(3)
2.060(3)
2.045(3)
2.066(3)
2.067(3)
1.988(5)
1.992(5)
1.992(5)
1.973(5)
N(1)–Pd(1)–C(14)
N(1)–Pd(1)–O(1)
N(1)–Pd(1)–O(4)
O(1)–Pd(1)–O(4)
N(2)–Pd(2)–C(30)
N(2)–Pd(2)–O(2)
N(2)–Pd(2)–O(3)
O(2)–Pd(2)–O(3)
N(3)–Pd(3)–C(46)
N(3)–Pd(3)–O(3)
N(3)–Pd(3)–O(1)
O(3)–Pd(3)–O(1)
N(4)–Pd(4)–C(62)
N(4)–Pd(4)–O(4)
N(4)–Pd(4)–O(2)
O(4)–Pd(4)–O(2)
94.6(2)
82.6(2)
176.2(2)
93.6(1)
95.0(2)
83.0(2)
174.6(2)
92.8(1)
93.0(2)
81.7(1)
176.3(2)
94.6(1)
92.9(2)
82.6(2)
176.4(2)
94.3(1)
ꢀ
Fig. 6. Molecular structure of 3g. Pd(1)–N(1) 2.010(6) A, Pd(1)–Cl(1)
ꢀ
2.275(2) A, Pd(1)–O(2) 2.032(6) A, Pd(1)–O(3A) 2.057(6) A. N(1)–
ꢀ
ꢀ
Pd(1)–Cl(1) 92.8(2)ꢁ, N(1)–Pd(1)–O(3A) 88.7(2)ꢁ, O(2)–Pd(1)–Cl(1)
88.7(2)ꢁ, Pdꢂ ꢂ ꢂPd 3.009 A.
ꢀ
For the crystals of the tetrameric palladium 7i Æ 1/
2CH2Cl2 crystallizes from a CH2Cl2/hexane solution
and in monoclinic space group P21=c. Fig. 7(a) shows
the ORTEP plot with thermal ellipsoid drawing at 50%
probability level, revealing the presence of a tetranuclear
neutral species. Selected bond distances and bond angles
of 7i are summarized in Table 4. The slightly distorted
square-planar environment of each Pd center is coordi-
nated by the nitrogen, carbon as well as oxygen atoms
from the same ligand, and one oxygen atom from the
other unit. This tetramer consists of four [Pd(Li-O,C,N)]
palladium fragments linked by bridging oxygen atom to
form a eight-membered ring of alternating Pd and O
atoms [11]. This resulting [Pd4O4] core has approximate
C2 symmetry [e.g. the C2 axis is perpendicular to and
bisecting Pd(3)–Pd(4) and Pd(1)–Pd(2)] yielding a saddle
conformation (Fig. 7(b)). The bond distances and bond
angles are virtually the same for each fragment.
core structure of the complex 3g. Both palladium metal
centers appear to be slightly distorted square-planar de-
fined by carbon ligand, the N-imine atom and two oxygen
atoms of acetate ligands. Like in the most instances, two
bulky imine ligands are seated in the trans orientation.
ꢀ
For the bond length of Pd(1)–N(1) [2.010(6) A] is essen-
tially similar to those of cyclopalladated species 1a, 1b and
ꢀ
1d. The Pdꢂ ꢂ ꢂPd distance of 3g (3.009 A) appears to be
shorter than those with chloro-bridged ones; however,
there is no metal–metal interaction.
3. Conclusion
Through this study, it was determined that the sub-
stituents on the arylimine readily influence the structure
of the cyclopalladated products. As expected, the cy-
clopalladation takes place preferentially at the position
to form 5-endo or 6-endo metallocycle over other pos-
sibility. However, the bulky substituents in Lg or Lh
hinder the occurrence of metallation. Furthermore, the
contribution of hydrogen bond interaction between
methoxy and hydroxy ligands in cis-1b allows the for-
mation of mixed-donor bridged complexes [Pd2(OH)Cl].
On the other hand, the hydroxy group in Li provides the
coordinating donor to form a tetrameric palladium
species. Further coordination chemistry of these related
complexes and their activity on catalysis are currently
under investigation.
Fig. 7. (a) ORTEP plot of 7i: (b) Conformation of [Pd4O4] core.

C.-L. Chen et al. / Journal of Organometallic Chemistry 689 (2004) 1806–1815
1811
4. Experimental
161.9, 161.1, 149.0, 138.0, 137.6, 124.2, 123.0, 106.2,
104.0, 55.6, 27.9, 23.5; FAB m=z: 325.1 (Mþ). Anal.
Calc. for C21H27NO2: C, 77.50; H, 8.36; N, 4.30. Found:
C, 77.53; H, 8.47; N, 4.30%.
4.1. General
All reaction’s, manipulation’s and purification’s steps
were performed under a dry nitrogen atmosphere. Tet-
rahydrofuran was distilled under nitrogen from sodium
benzophenone ketyl. Dichloromethane and acetonitrile
were dried with CaH2 and distilled under nitrogen.
Other chemicals and solvents were of analytical grade
and were used as received unless otherwise stated.
Nuclear magnetic resonance spectra were recorded in
CDCl3 on either a Bruker AM-300 or AVANCE-400
spectrometer. Chemical shifts are given in parts per
million relative to Me4S for 1H and relative 85% H3PO4
for 31P NMR. Infrared spectra were measured on a
Perkin–Elmer 983G spectrometer (Series-II) as KBr
pallets, unless otherwise noted. Mass spectra were ob-
tained from a Joel JMSD-300 instrument.
4.2.4. (3,5-Difluorobenzylidene)(2,6-diisopropylphenyl)
amine (Lc)
1
Yellow solid (95%): IR (KBr): 1595 cmꢀ1 (mC@N); H
NMR (CDCl3, 400 MHz): d 8.11 (s, 1H, –HC@N), 7.42
(d, JHF ¼ 5:8 Hz, 2H, Ar H), 7.16–7.08 (m, 3H, Ar H),
6.94 (t, JHF ¼ 8:6 Hz, 1H, Ar H), 2.89 (sept., J ¼ 6:8 Hz,
2H, –CH), 1.15 (d, J ¼ 6:8 Hz, 12H, –Me); 13C NMR: d
163.3 (dd, JCF ¼ 248:3 Hz, 12.5 Hz), 159.6, 148.4, 139.2,
137.3, 124.6, 123.1, 111.2 (dd, JCF ¼ 18:6 Hz, 7.0 Hz),
106.6 (t, JCF ¼ 25:4 Hz), 28.0, 23.4; EI m=z: 301.1 (Mþ).
Anal. Calc. for C19H21F2N C, 75.72; H, 7.02; N, 4.65.
Found: C, 75.67; H, 6.97; N, 4.44%.
4.2.5. [3,5-bis(20,60- dimethoxyphenyl)benzylidene](2,6-
Diisopropylphenyl)amine (Ld )
1
4.2. Synthesis and characterization
White solid (85%), IR (KBr): 1635 cmꢀ1 (mC@N); H
NMR (CDCl3, 400 MHz): d 8.23 (s, 1H, –HC@N), 7.88
(d, J ¼ 1:2 Hz, 2H, Ar H), 7.58 (t, J ¼ 1:2 Hz, 1H, Ar
H), 7.28 (t, J ¼ 8:4 Hz, 2H, Ar H), 7.15–7.09 (m, 3H, Ar
H), 6.66 (d, J ¼ 8:4 Hz, 4H, Ar H), 3.77 (s, 12H, –OMe),
3.06 (sept, J ¼ 6:8 Hz, 2H, –CH), 1.16 (d, J ¼ 6:8 Hz,
12H, –Me); 13C NMR: d 162.5, 157.7, 149.6, 137.7,
137.3, 134.7, 133.3, 130.2, 128.7, 123.7, 122.9, 118.8,
104.1, 55.9, 27.7, 23.5; FAB m=z: 537.3 (Mþ). Anal.
Calc. for C35H39NO4: C, 78.18; H, 7.31; N, 2.61. Found:
C, 78.11; H, 7.02; N, 2.35%.
4.2.1. General procedure for preparation of Schiff base
ligands (La–i
)
A methanol (15 ml) solution of the substituted
benzylaldehyde (10 mmol) was added to the substi-
tuted aniline (10 mmol) in a round-bottomed flask
equipped with a condenser. The reaction mixture was
stirred at reflux temperature for 24 h. After the com-
pletion of reaction, the yellow crystal product was pre-
cipitated upon cooling. The solid product was filtered,
washed with the pre-cold methanol and dried, whereas
the liquid compounds La and Lh were purified by dis-
tillation off the starting aldehyde and chromatographied
on aluminium oxide with elution of hexane. 3,5-Di-
methoxybenzaldehyde was prepared according to the
method reported [13].
4.2.6.(4-Chlorobenzylidene)(2,6-diisopropylphenyl)amine
(Le)
1
Yellow solid (92%); IR (KBr): 1640 cmꢀ1 (mC@N); H
NMR (CDCl3, 400 MHz): d 8.14 (s, 1H, –HC@N), 7.83
(d, J ¼ 8:2 Hz, 2H, Ar H), 7.46 (d, J ¼ 8:2 Hz, 2H, Ar
H), 7.15–7.07 (m, 3H, Ar H), 2.92 (sept., J ¼ 6:9 Hz,
2H, –CH), 1.15 (d, J ¼ 6:9 Hz, 12H, –Me); 13C NMR: d
160.6, 148.9, 137.5, 137.4, 134.4, 129.7, 129.1, 124.3,
123.0, 27.9, 23.4; FAB m=z: 299.1 (Mþ). Anal. Calc. for
C19H22ClN: C, 76.11; H, 7.40; N, 4.67. Found: C, 76.22;
H,7.41; N, 4.70%.
4.2.2. Benzylidene(2,6-diisopropylphenyl)amine (La)
Light yellow liquid (92%): IR (KBr): 1646 cmꢀ1
1
(mC@N); H NMR (CDCl3, 400 MHz): d 8.20 (s, 1H, –
HC@N), 7.93–7.88 (m, 2H, Ar H), 7.52–7.48 (m, 3H, Ar
H), 7.18–7.09 (m, 3H, Ar H), 2.95 (sept., J ¼ 9:2 Hz,
2H, –CH), 1.16 (d, J ¼ 9:2 Hz, 12H, –Me); 13C NMR: d
162.0, 149.2, 137.6, 136.0, 131.4, 128.8, 128.6, 124.1,
123.0, 27.9, 23.5. There spectra data are consistent with
the reported ones [12].
4.2.7. (2-Bromobenzylidene)(2,6-diispropylphenyl)amine
(Lf )
1
Yellow solid (90%); IR (KBr): 1632 cmꢀ1 (mC@N); H
NMR (CDCl3, 400 MHz): d 8.56 (s, 1H, –HC@N), 8.25
(d, J ¼ 8:0 Hz, 1H, Ar H), 7.62 (d, J ¼ 8:0 Hz, 1H, Ar
H), 7.44 (t, J ¼ 8:0 Hz, 1H, Ar H), 7.35 (t, J ¼ 8:0 Hz,
1H, Ar H), 7.18–7.11 (m, 3H, Ar H), 2.96 (sept., J ¼ 6:9
Hz, 2H, –CH), 1.19 (d, J ¼ 6:9 Hz, 12H, –Me); 13C
NMR: d 161.4, 148.9, 137.5, 134.5, 133.2, 132.4, 128.8,
127.8, 125.7, 124.4, 123.1, 27.9, 23.5; FAB m=z: 343.1
(Mþ). Anal. Calc. for C19-H22BrN: C, 66.28; H, 6.44; N,
4.07. Found: C, 66.23; H, 6.52; N, 4.29%.
4.2.3. (3,5-Dimethoxybenzylidene)(2,6-diisopropylphenyl)-
amine (Lb)
1
Yellow solid (95%): IR (KBr): 1604 cmꢀ1 (mC@N); H
NMR (CDCl3, 400 MHz): d 8.11 (s, 1H, –HC@N), 7.17
(d, J ¼ 6:7 Hz, 2H, Ar H), 7.10 (d, J ¼ 6:7 Hz, 1H, Ar
H), 7.07 (d, J ¼ 2:3 Hz, 2H, Ar H), 6.62 (t, J ¼ 2:3 Hz,
1H, Ar H), 3.87 (s, 6H, –OMe); 2.97 (sept., J ¼ 6:9 Hz,
2H, –CH), 1.17 (d, J ¼ 6:9 Hz, 12H, –Me); 13C NMR: d

1812
C.-L. Chen et al. / Journal of Organometallic Chemistry 689 (2004) 1806–1815
4.2.8. (3,5-Di-tert-butyl-4-methoxybenzylidene)(2,6-diiso-
propylphenyl)amine (Lg)
4.3.1. Complex 1a
Yellow solid (75%): IR (KBr): 1603 cmꢀ1 (mC@N); H
NMR (CDCl3, 400 MHz): d 7.72 (s, 1H, –HC@N),
7.35–6.95 (m, 7H, Ar H), 3.55–3.45 (m, 2H, –CH), 1.36
(d, J ¼ 6:4 Hz, 6H, –Me), 1.12 (d, J ¼ 6:6 Hz, 6H, –
Me); 13C NMR: d 176.2, 155.4, 145.7, 144.3, 141.5,
133.9, 130.9, 127.9, 127.7, 124.7, 123.2, 28.2, 24.4, 23.0;
FAB m=z: 777.1 (Mþ–Clꢀ). Anal. Calc. for
C38H44Cl2N2Pd2: C, 56.17; H, 5.46; N, 3.45. Found: C,
56.09; H, 5.49; N, 3.40%.
1
Yellow solid (92%): m.p.: 113–114 ꢁC; IR (KBr): 1645
1
cmꢀ1 (mC@N); H NMR (CDCl3, 400 MHz): d 8.09 (s,
1H, –HC@N), 7.79 (s, 2H, Ar H), 7.15–7.09 (m, 3H,
Ar H), 3.76 (s, 3H, –OMe), 2.99 (sept, J ¼ 6:8 Hz, 2H,
–CH), 1.48 (s, 18H, –Me), 1.17 (d, J ¼ 6:8 Hz, 12H,
–Me); 13C NMR: d 162.7, 161.9, 149.4, 144.5, 137.8,
130.6, 127.2, 123.9, 122.9, 64.4, 35.9, 32.0, 27.9, 23.5;
FAB m=z: 407.3 (Mþ). Anal. Calc. for C28H41NO: C,
82.50; H, 10.14; N, 3.44. Found: C, 82.63; H, 10.38; N,
3.16%.
4.3.2. Complex trans-1b
Yellow solid; IR (KBr): 1584 cmꢀ1 (mC@N); H NMR
1
(CDCl3, 400 MHz): d 7.66 (s, 1H, –HC@N), 7.63 (s, 1H,
–HC@N), 7.22 (t, J ¼ 7:5 Hz, 1H, Ar H), 7.11 (d,
J ¼ 7:5 Hz, 2H, Ar H), 7.08 (t, J ¼ 7:6 Hz, 1H, Ar H),
6.92 (d, J ¼ 7:6 Hz, 2H, Ar H), 6.53 (s, 1H, Ar H), 6.52
(s, 1H, Ar H), 6.30 (s, 1H, Ar H), 6.19 (s, 1H, Ar H),
3.79 (s, 3H, –OMe), 3.76 (s, 3H, –OMe), 3.74 (s, 3H, –
OMe), 3.55–3.45 (m, 2H, –CH), 3.41 (s, 3H, –OMe),
3.34–3.24 (m, 2H, –CH), 1.39 (d, J ¼ 6:7 Hz, 6H, –Me),
1.14 (d, J ¼ 6:7 Hz, 6H, –Me), 1.10 (d, J ¼ 6:7 Hz, 6H,
–Me), 1.01 (d, J ¼ 6:7 Hz, 6H, –Me); 13C NMR (CDCl3,
100 MHz): d 177.2, 177.0, 165.0, 164.7, 158.4, 146.7,
144.3, 142.7, 141.7, 141.6, 132.8, 132.4, 127.4, 127.3,
123.0, 122.6, 104.8, 104.7, 104.1, 103.4, 55.9, 55.4, 28.2,
28.0, 24.6, 24.5, 22.8, 22.7; FAB m=z: 932.1 (Mþ), 897.1
(Mþ–Clꢀ). Anal. Calc. for C42H52Cl2N2O4Pd2 Æ
2C4H8O: C, 55.77; H, 6.36; N, 2.60. Found: C, 55.58; H,
6.17; N, 2.38%.
4.2.9. (3,5-Di-tert-butyl-4-methoxybenzylidene)(2,6-di-
methylphenyl)amine (Lh)
Orange liquid (85%); IR (KBr): 1646 cmꢀ1 (mC@N); 1H
NMR (CDCl3, 300 MHz): d 8.20 (s, 1H, –HC@N), 7.88
(s, 2H, Ar H), 7.12 (d, J ¼ 7:6 Hz, 2H, Ar H), 7.00 (d,
J ¼ 7:6 Hz, 1H, Ar H), 3.81 (s, 3H, –OMe), 2.22 (s, 6H,
–Me), 1.55 (s, 18H, –Me), 13C NMR: d 162.8, 162.7,
151.5, 144.5, 130.7, 128.0, 127.3, 127.1, 123.5, 64.5, 36.0,
32.1, 18.5; FAB m=z: 351.3 (Mþ). Anal. Calc. for
C28H41NO: C, 82.50; H, 7.31; N, 2.61. Found: C, 82.12;
H, 6.97; N, 2.27%.
4.2.10. (2,4,6-Trimethylbenzylidene)(2,6-dihydroxyphe-
nyl)amine (Li)
Pale brown solid (82%); IR (KBr): 1630 cmꢀ1 (mC@N);
1H NMR (CDCl3, 400 MHz): d 9.10 (s, 1H, –HC@N),
7.28(d, J ¼ 6:6 Hz,1H, Ar H), 7.21(t, J ¼ 8:0 Hz, 1H,
Ar H), 7.04(d, J ¼ 8:0 Hz, 1H, Ar H), 6.97 (s, 2H, Ar
H), 6.94 (t, J ¼ 6:8 Hz, 2H, Ar H), 2.59(s, 6H, –Me),
2.35(s, 3H, –Me); 13C NMR: d 157.7, 152.0, 140.4,
138,9, 136.8, 130.1, 129.9, 128.4, 120.0, 115.4, 114.8,
21.5, 21.2; FAB m=z: 240.2 (Mþ + 1). Anal. Calc. for
C16H17NO: C, 80.30; H, 7.16; N, 5.85. Found: C, 80.15;
H, 7.26; N, 5.50%.
4.3.3. Complex cis-1b
1
IR (KBr): 1586 cmꢀ1 (mC@N); H NMR (CDCl3, 400
MHz): d 7.56 (s, 1H, –HC@N), 7.12 (t, J ¼ 7:5 Hz, 1H,
Ar H), 6.99 (d, J ¼ 7:5 Hz, 2H, Ar H), 6.58 (d, J ¼ 2:4
Hz, 1H, Ar H), 6.38 (d, J ¼ 2:4 Hz, 1H, Ar H), 3.84 (s,
3H, –OMe), 3.78 (s, 3H, –OMe), 3.35 (sept., J ¼ 6:8 Hz,
2H, –CH), 2.81 (s, 1H, OH) 1.21 (d, J ¼ 6:8 Hz, 6H, –
Me), 1.02 (d, J ¼ 6:8 Hz, 6H, –Me); 13C NMR (CDCl3,
100 MHz): d 176.0, 165.8, 158.1, 146.5, 143.8, 141.4,
131.6, 127.3, 123.0, 104.9, 104.0, 57.2, 55.5, 27.9, 24.4,
23.0. Due to the co-crystallization with trans-1b, ele-
mental analysis of this compound cannot be obtained.
4.3. Generanl procedure for preparation of palladacycle
complexes 1a–f
To a round-bottomed flask with a stir bar was placed
with palladium dichloride (118 mg, 0.67 mmol) under
the nitrogen. Pre-dried acetonitrile (10 ml) was added
and the resulting mixture was stirred at room tempera-
ture. The mixture turned into yellow color immediately.
After stirring for two days, the solvent was removed to
dryness. Then ligand (0.71 mmol), excess of sodium
acetate (110 mg, 10.4 mmol) and tetrahydrofuran
(15 ml) were added. The reaction mixture was stirred at
room temperature for another 38 h. After removal of
solvents, dichloromethane (20 ml) was added and the
solution was filtered through cilite. The filtrate was
concentrated and the residue was washed with hexane
(10 ml · 3) to give the desired product.
4.3.4. Complex 1c
1
Yellow solid (65%): IR (KBr): 1570 cmꢀ1 (mC@N); H
NMR (CDCl3, 400 MHz): d 7.70 (s, 1H, –HC@N), 7.67
(s, 1H, –HC@N), 7.29 (t, J ¼ 7:7 Hz, 1H, Ar H), 7.15 (d,
J ¼ 7:7 Hz, 2H, Ar H), 7.12 (t, J ¼ 7:7 Hz, 1H, Ar H),
6.95 (d, J ¼ 7:7 Hz, 2H, Ar H), 6.91 (d, JH–F ¼ 7:0 Hz,
2H, Ar H), 6.64 (dd, JH–F ¼ 7:9 Hz, JH–F ¼ 7:9 Hz, 1H,
Ar H), 6.53(dd, JH–F ¼ 7:9 Hz, JH–F ¼ 7:9 Hz, 1H, Ar
H), 3.40 (sept., J ¼ 6:7 Hz, 2H, –CH), 3.20 (sept.,
J ¼ 6:7 Hz, 2H, –CH), 1.41 (d, J ¼ 6:7 Hz, 6H, –Me),
1.17 (d, J ¼ 6:7 Hz, 6H, –Me), 1.13 (d, J ¼ 6:7 Hz, 6H,
–Me), 1.04 (d, J ¼ 6:7 Hz, 6H, –Me); 13C NMR (CDCl3,

C.-L. Chen et al. / Journal of Organometallic Chemistry 689 (2004) 1806–1815
1813
100 MHz): d 176.6, 176.4, 167.3 (d, JC–F ¼ 247 Hz),
167.2 (d, JC–F ¼ 247 Hz), 160.8 (d, JC–F ¼ 244 Hz),
160.7 (d, JC–F ¼ 244 Hz), 147.5 (d, JC–F ¼ 16 Hz), 147.4
(d, JC–F ¼ 16 Hz), 143.8, 142.2, 141.3, 141.2, 130.2 (d,
JC–F ¼ 36 Hz), 130.1 (d, JC–F ¼ 36 Hz), 128.3, 127.9,
123.4, 122.9, 111.0 (d, JC–F ¼ 22 Hz), 110.9 (d, JC–F ¼ 22
Hz), 108.1 (d, JC–F ¼ 32 Hz), 107.8 (d, JC–F ¼ 32 Hz),
28.4, 28.2, 24.5, 22.7, 22.6; FAB m=z: 849.0 (Mþ–Clꢀ).
Anal. Calc. for C38H40Cl2F4N2Pd2: C, 51.50; H, 4.56;
N, 3.17. Found: C, 51.38; H, 4.58; N, 3.11%.
J ¼ 6:7 Hz, 1H, –CH),2.20 (d, J ¼ 6:7 Hz, 3H, –Me),
1.97 (s, 3H, –Me), 1.36 (d, J ¼ 6:7 Hz, 3H, –Me), 1.31
(d, J ¼ 6:7 Hz, 3H, Me), 1.15 (s, 18H, Me), 0.26 (d,
J ¼ 6:7 Hz, 3H, Me); 13C NMR: d 185.4, 176.1, 164.0,
144.3, 143.6, 141.6, 140.2, 128.2, 127.0, 125.0, 124.7,
64.4, 35.7, 31.5, 29.2, 28.5, 26.4, 24.8, 24.1,23.9, 22.8;
FAB m=z: 1181.4 (Mþ–Clꢀ). Anal. Calc. for
C60H88Cl2N2O6Pd2 Æ H2O: C, 58.35; H, 7.34; N, 2.27.
Found: C, 58.63; H, 7.12; N, 2.06%.
4.3.9. Complex 3h
1
4.3.5. Complex 1d
Brown solid (77%): IR (KBr): 1613 cmꢀ1 (mC@N); H
1
Yellow solid (56%); IR (KBr): 1591 cmꢀ1 (mC@N); H
NMR (CDCl3, 400 MHz): d 9.32 (s, 1H, –HC@N), 7.25
(d, J ¼ 7:5 Hz, 1H, Ar H), 7.17 (dd, J ¼ 7:5 Hz, J ¼ 7:5
Hz, 1H, Ar H), 7.13 (s, 2H, Ar H), 7.03 (d, J ¼ 7:5 Hz,
1H, Ar H), 3.61 (s, 3H, –OMe), 2.88 (s, 3H, –Me), 2.11
(s, 3H, –Me), 1.76 (s, 3H, –Me), 1.27 (s, 18H, Me); 13C
NMR (CDCl3, 100 MHz): d 184.6, 176.0, 163.9, 144.5,
144.3, 131.6, 131.1, 129.8, 129.4,s 128.7, 127.5,126.6,
64.4, 35.7, 31.6, 23.1, 20.0, 18.4; FAB m=z: 1044.3 (Mþ–
OAcꢀ). Anal. Calc. for C52H72Cl2N2O6Pd2 Æ H2O: C,
55.62; H, 6.64; N, 2.49. Found: C, 55.66; H, 6.63; N,
2.38%.
NMR (CDCl3, 400 MHz): d 7.61 (s, 1H, –HC@N), 7.28
(t, J ¼ 7:7 Hz, 1H, Ar H), 7.20 (d, J ¼ 2:1 Hz, 1H, Ar
H), 7.16 (t, J ¼ 8:3 Hz, 1H, Ar H), 7.08 (d, J ¼ 7:7 Hz,
2H, Ar H), 6.82 (d, J ¼ 2:1 Hz, 1H, Ar H), 6.77 (t,
J ¼ 8:3 Hz, 1H, Ar H), 6.55 (d, J ¼ 8:3 Hz, 2H, Ar H),
6.18 (d, J ¼ 8:3 Hz, 2H, Ar H), 3.71 (s, 6H, –OMe), 3.67
(s, 6H, –OMe), 3.42 (sept., J ¼ 6:8 Hz, 2H, –CH), 1.32
(d, J ¼ 6:8 Hz, 6H, –Me), 1.11 (d, J ¼ 6:8 Hz, 6H, –
Me); 13C NMR: d 176.9, 157.6, 157.5, 153.8, 145.5,
144.3, 141.5, 139.3, 138.0, 129.5, 129.0, 128.3, 128.2,
127.2, 123.1, 122.5, 118.2, 105.1, 104.2, 56.3, 55.8, 27.8,
24.6,
23.3;
FAB
m=z:
1355.3
(Mþ + 1);
4.3.10. Complex 3h0
1
C70H76Cl2N2O8Pd2: C, 61.95; H, 5.64; N, 2.06. Found:
C, 61.81; H, 5.55; N, 2.04%.
Yellow solid (20%): IR (KBr): 1613 cmꢀ1 (mC@N); H
NMR (CDCl3, 400 MHz): d 8.81 (s, 1H, –HC@N), 7.07
(brs, 3H, Ar H), 6.92 (s, 2H, Ar H), 3.58 (s, 3H, –OMe),
2.38 (s, 6H, –Me), 1.18 (s, 18H, Me); 13C NMR (CDCl3,
100 MHz): d 173.8, 163.8, 146.0, 144.5, 130.8, 130.0,
128.9, 127.2, 126.9, 64.3, 35.7, 31.5, 19.8. Anal. Calc. for
C48H66Cl4N2O2Pd2: C, 54.51; H, 5.97; N, 2.33. Found:
C, 53.98; H, 5.97; N, 2.33%.
4.3.6. Complex 1e
Yellow solids (75%): IR (KBr): 1602 cmꢀ1 (mC@N); 1H
NMR (CDCl3, 400 MHz): d 7.70 (s, 1H, –HC@N), 7.32
(brs, 1H, Ar H), 7.20–6.95 (m, 5H, Ar H), 3.43 (brs, 2H,
–CH), 1.36 (br, 6H, –Me), 1.12 (d, J ¼ 6:4 Hz, 6H,
–Me); 13C NMR: d 175.4, 156.0, 144.0, 143.8, 141.3,
136.7, 133.4, 128.6, 128.2, 125.2, 123.4, 28.3, 24.4, 22.9;
FAB m=z: 844.1 (Mþ–Clꢀ). Anal. Calc. for
C38H42Cl4N2Pd2: C, 51.78; H, 4.80; N, 3.18. Found: C,
51.89; H, 4.74; N, 3.29%.
4.3.11. Complex 7i
1
Brown solid (55%): IR (KBr) 1595 cmꢀ1 (mC@N); H
NMR (CDCl3, 400 MHz): d 8.05 (s, 1H, –HC@N), 7.79
(d, J ¼ 8:4 Hz, 1H, Ar H), 7.10 (t, J ¼ 8:4 Hz, 1H, Ar
H), 6.87 (d, J ¼ 8:4 Hz, 1H, Ar H), 6.75 (s, 1H, Ar H),
6.54 (s, 1H, Ar H), 6.45 (t, J ¼ 8:4 Hz, 1H, Ar H), 3.40
(d, J ¼ 13:6 Hz, 1H, –H2C–Pd), 2.52 (d, J ¼ 13:6 Hz,
4.3.7. Complex 1f
1
Yellow solid (76%): IR (KBr): 1588 cmꢀ1 (mC@N); H
NMR (CDCl3, 400 MHz): d 8.10 (s, 1H, –HC@N), 7.31
(t, J ¼ 7:8 Hz, 1H, Ar H), 7.20–7.10 (m, 3H, Ar H), 7.11
(d, J ¼ 7:8 Hz, 1H, Ar H), 6.87 (t, J ¼ 7:8 Hz, 1H, Ar
H), 3.49 (sept., J ¼ 6:9 Hz, 2H, –CH), 1.36 (d, J ¼ 6:9
Hz, 6H, –Me), 1.15 (d, J ¼ 6:9 Hz, 6H, –Me); FAB m=z:
933.0 (Mþ–Clꢀ). Anal. Calc. for C38H42Br2Cl2N2Pd2:
C, 47.04; H, 4.36; N, 2.89. Found: C, 46.90; H, 4.26; N,
2.85%.
1H, –H2C–Pd), 2.24 (s, 3H, –Me), 2.23 (s, 3H, –Me); 13
C
NMR: d 163.7, 147.0, 146.5, 139.9, 139.5, 139.4, 130.1,
129.8, 127.6, 127.5, 123.2, 115.3, 114.7, 21.4, 21.3, 20.5;
FAB m=z: 1374.2 (Mþ). Anal. Calc. for
C64H60N4O4Pd4: C, 55.91; H, 4.40; N, 4.08. Found: C,
56.17; H, 4.34; N, 4.10%.
4.4. X-ray crystallographic analysis
4.3.8. Complex 4g
Crystals suitable for X-ray determination were ob-
tained for 1a, trans-1b, cis-1b, 1d, 3g and 7i by re-crys-
tallization at room temperature. Cell parameters were
determined either by a Siemens SMART CCD diffrac-
tometer. Crystal data of the complexes 1a, trans-1b, cis-
1b, 1d, 3g are listed in Table 5, whereas the complex
Brown solid (95%): IR (KBr): 1612 cmꢀ1 (mC@N);1H
NMR (CDCl3, 400 MHz): d 9.41 (s, 1H, –HC@N), 7.46
(d, J ¼ 7:5 Hz, 1H, Ar H), 7.39 (dd, J ¼ 7:5 Hz, 7.5 Hz
1H, Ar H), 7.09 (d, J ¼ 7:5 Hz, 1H, Ar H), 4.81 (sept.,
J ¼ 6:7 Hz, 1H, –CH), 3.54 (s, 3H, –OMe), 2.91 (sept.,

1814
C.-L. Chen et al. / Journal of Organometallic Chemistry 689 (2004) 1806–1815
Table 5
Selected crystallographic data of complexes 1a, cis-1b, trans-1b, 1d and 3g
Complex
1a
cis-1b/trans-1b
trans-1b
1d
3g
Formula
C19H22ClNPd
406.23
C63H79Cl2N3O7Pd3
1380.39
Triclinic
C25H34ClNO3Pd
538.38
C72H80Cl6N2O8Pd2
1526.88
Triclinic
C60H88Cl2N2O6Pd2
1217.02
Formula weight
Crystal system
Space group
Monoclinic
P21=c
11.100(1)
10.321(1)
16.724(2)
90
Monoclinic
P21=n
11.3480(1)
18.4890(2)
12.2610(1)
90
Monoclinic
P21=c
11.2648(2)
45.3399(8)
12.5379(2)
90
ꢂ
ꢂ
P1
P1
ꢀ
a (A)
13.0160(2)
13.2052(2)
19.9799(2)
90.214 (3)
107/806 (3)
105.478(3)
3137.38(7)
2
11.0260(1)
13.8190(2)
13.8230(2)
69.447 (1)
68.661 (1)
69.886 (1)
1779.62(4)
1
ꢀ
b (A)
ꢀ
c (A)
a (ꢁ)
b (ꢁ)
c (ꢁ)
104.828 (2)
90
90.546 (1)
90
111.9727 (6)
90
3
ꢀ
V (A )
1852.1(3)
4
1.457
2572.40(4)
4
1.390
5938.5(2)
4
1.361
Z
Dcalcd (Mg/m3)
1.461
1412
1.425
784
F ð000Þ
824
1112
2544
Crystal size (mm)
h range (ꢁ)
Reflection collected
0.20 · 0.20 · 0.35
1.90–27.50
24 923
0.25 · 0.20 · 0.20
1.08–25.00
20 080
0.30 · 0.20 · 0.20
1.99–25.00
15 395
0.25 · 0.20 · 0.15
1.64–27.49
27 363
0.12 · 0.06 · 0.01
2.97–25.00
45 221
Independent reflection
4264 (0.0234)
11 050 (0.0444)
4518 (0.0247)
8143 (0.0563)
10 390 (0.1352)
(Rint
Refined method
)
Full-matrix least-squares on F 2
R [I > 2rðIÞ]
R1 ¼ 0:0193,
wR2 ¼ 0:0480,
1.052
R1 ¼ 0:0437,
wR2 ¼ 0:1030
1.078
R1 ¼ 0:0302,
wR2 ¼ 0:0782
1.177
R1 ¼ 0:0426,
wR2 ¼ 0:1046
1.041
R1 ¼ 0:0783,
wR2 ¼ 0:1504
1.073
Goodness-of-fit on F 2
7i(1/2CH2Cl2): C64:5H61ClN4O4Pd4, formula weight ¼
References
ꢀ
1417.22, monoclinic, P21=c, a ¼ 18:5390ð3Þ A, b ¼
ꢀ
ꢀ
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Crystallographic data (excluding structure factors)
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