Reactivity of C(sp2)-Pd and C(sp3)-Pd bonded palladacycles with diphosphines. Crystal and molecular structure of the novel A-frame complex [{Pd[2,5-Me2C6H2C(H)N(2,4,6- Me3C6H2)-C6]}2(μ-Ph 2PCH2PPh2)2(μ-Cl)][PF 6]

Article abstract of DOI:10.1016/j.jorganchem.2010.09.071

Treatment of the halogen-bridged complexes [Pd{2,5-Me₂C ₆H₂C(H)N(2,4,6-Me₃C₆H ₂)-C6,N}(μ-X)]₂ (1a, X = Cl; 2a, X = Br) with the tertiary diphosphine Ph₂PCH₂PPh₂ (dppm), regardless of the molar ratio used, gave a mixture of two complexes: [Pd{2,5-Me₂C₆H₂C(H)N(2,4,6-Me₃C ₆H₂)-C6}(μ-Ph₂PCH₂PPh ₂)₂(μ-X)]₂[PF₆] (5a, X = Cl; 6a, X = Br), which presents an A-frame structure, and [Pd{2,5-Me₂C ₆H₂C(H)N(2,4,6-Me₃C₆H ₂)-C6,N}(Ph₂PCH₂PPh₂-P,P)][PF ₆], 3a, with the diphosphine as chelating. The mixture could be separated and the corresponding complexes isolated. However, reaction of 1a and 2a with the diphosphine Ph₂PC(CH₂)PPh₂ (vdpp) exclusively gave the mononuclear complex [Pd{2,5-Me₂C ₆H₂C(H)N(2,4,6-Me₃C₆H ₂)-C6,N}{Ph₂PC(CH₂)PPh₂-P,P}] [PF₆], 4a, analogous to 3a. Treatment of the halogen-bridged complexes [Pd{1-CH₂-2-[HCN(2,4,6-Me₃C₆H ₂)]-4-MeC₆H₃-C,N}(μ-X)]₂ (1a′, X = Cl; 2a′, X = Br) with dppm or vdpp in a cyclometallated complex/diphosphine 1:2 M ratio, gave mononuclear complexes with the chelating diphospines [Pd{1-CH₂-2-[HCN(2,4,6-Me₃C₆H ₂)]-4-MeC₆H₃-C,N}(Ph₂PCH ₂PPh₂-P,P)][PF₆], 3a′, and [Pd{1-CH ₂-2-[HCN(2,4,6-Me₃C₆H₂)]-4-MeC ₆H₃-C,N}{Ph₂PC(CH₂)PPh ₂-P,P}][PF₆], 4a′. When the reaction was carried out using a cyclometallated complex/diphosphine 1:1 M ratio the dinuclear complexes [{Pd[1-CH₂-2-{HCN(2,4,6-Me₃C₆H ₂)}-4-MeC₆H₃-C,N]}₂(μ-X)(μ- Ph₂PCH₂PPh₂)][Cl], (5a′, X = Cl; 7a′, X = Br) and [{Pd[1-CH₂-2-{HCN(2,4,6-Me₃C ₆H₂)}-4-MeC₆H₃-C,N]} ₂(μ-Cl){μ-Ph₂PC(CH₂)PPh ₂}][Cl], 6a′, were obtained. The molecular structures of complexes 3a, 4a, 5a and 6a′ were determined by X-ray single crystal diffraction.

Full text of DOI:10.1016/j.jorganchem.2010.09.071

Journal of Organometallic Chemistry 696 (2011) 764e771
Contents lists available at ScienceDirect
Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
Reactivity of C(sp2)-Pd and C(sp3)-Pd bonded palladacycles with diphosphines.
Crystal and molecular structure of the novel A-frame complex [{Pd[2,5-Me2C6H2C
(H)]N(2,4,6-Me3C6H2)-C6]}2(
m
-Ph2PCH2PPh2)2(
m
-Cl)][PF6]
,
a
a
Digna Vázquez-García a, Alberto Fernández a , Margarita López-Torres , Antonio Rodríguez ,
**
Nina Gómez-Blanco a, Carlos Viader a, José M. Vila b , Jesús J. Fernández
,
a
*
a Departamento de Química Fundamental, Universidade da Coruña, 15071 A Coruña, Spain
b Departamento de Química Inorgánica, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain
a r t i c l e i n f o
a b s t r a c t
Article history:
Treatment of the halogen-bridged complexes [Pd{2,5-Me2C6H2C(H)]N(2,4,6-Me3C6H2)-C6,N}(m-X)]2
Received 5 August 2010
Received in revised form
28 September 2010
Accepted 29 September 2010
Available online 8 October 2010
(1a, X ¼ Cl; 2a, X ¼ Br) with the tertiary diphosphine Ph2PCH2PPh2 (dppm), regardless of the
molar ratio used, gave a mixture of two complexes: [Pd{2,5-Me2C6H2C(H)]N(2,4,6-Me3C6H2)-C6}
(
m
-Ph2PCH2PPh2)2(
m
-X)]2[PF6] (5a, X ¼ Cl; 6a, X ¼ Br), which presents an A-frame structure, and [Pd{2,5-
Me2C6H2C(H)]N(2,4,6-Me3C6H2)-C6,N}(Ph2PCH2PPh2-P,P)][PF6], 3a, with the diphosphine as chelating.
The mixture could be separated and the corresponding complexes isolated. However, reaction of 1a and
2a with the diphosphine Ph2PC(]CH2)PPh2 (vdpp) exclusively gave the mononuclear complex [Pd{2,5-
Me2C6H2C(H)]N(2,4,6-Me3C6H2)-C6,N}{Ph2PC(]CH2)PPh2-P,P}][PF6], 4a, analogous to 3a. Treatment of
Keywords:
Palladium
Cyclometallation
diphosphines
A-frame structure
the halogen-bridged complexes [Pd{1-CH2-2-[HC]N(2,4,6-Me3C6H2)]-4-MeC6H3-C,N}(m
-X)]2 (1a0,
X ¼ Cl; 2a0, X ¼ Br) with dppm or vdpp in a cyclometallated complex/diphosphine 1:2 M ratio, gave
mononuclear complexes with the chelating diphospines [Pd{1-CH2-2-[HC]N(2,4,6-Me3C6H2)]-
4-MeC6H3-C,N}(Ph2PCH2PPh2-P,P)][PF6], 3a0, and [Pd{1-CH2-2-[HC]N(2,4,6-Me3C6H2)]-4-MeC6H3-C,N}
{Ph2PC(]CH2)PPh2-P,P}][PF6], 4a0. When the reaction was carried out using a cyclometallated complex/
diphosphine 1:1 M ratio the dinuclear complexes [{Pd[1-CH2-2-{HC]N(2,4,6-Me3C6H2)}-4-MeC6H3-
C,N]}2(
4-MeC6H3eC,N]}2(
m
-X)(
m
-Ph2PCH2PPh2)][Cl], (5a0, X ¼ Cl; 7a0, X ¼ Br) and [{Pd[1-CH2-2-{HC]N(2,4,6-Me3C6H2)}-
m
-Cl){m
-Ph2PC(]CH2)PPh2}][Cl], 6a0, were obtained. The molecular structures of
complexes 3a, 4a, 5a and 6a0 were determined by X-ray single crystal diffraction.
Ó 2010 Elsevier B.V. All rights reserved.
1. Introduction
it is absent. [30e37] On the other hand, we have shown that
diphosphine ligands present a variable coordination behaviour
depending on the reaction conditions and on the relative cyclo-
metallated complex/diphosphine molar ratio; thus, mononuclear
complexes with the diphosphine as a chelating ligand, or dinuclear
complexes with a bridging diphosphine ligand may be obtained.
[38e45] Furthermore, the phosphine carbon chain determines the
structure of the dinuclear complexes: neutral dinuclear complexes
with two palladium-halogen terminal bonds are obtained with long-
chain diphosphines; however, with dppm or vdpp, complexes with
bridging diphosphine and halogen ligands may be prepared. [46e49]
We have shown that ligand a can be metallated at an aliphatic or
at a sterically hindered aromatic carbon to give five- and six-
membered palladacycles [37] and herein we present new features
in the reactivity of the corresponding cyclomatallated compounds
towards diphosphines, namely the preparation of dinuclear
compounds with a triple bridge between the two palladium atoms:
two diphosphine ligands and a halogen atom, in an A-frame
Cyclometallated transition metal complexes are an important
group of species within organometallic chemistry, showing many
applications [1e13] and giving rise to new and unexpected coordi-
nation possibilities. [14] They have been studied to a great degree,
among other reasons, owing to the great number of organic
substrates which may undergo the cyclometallation reaction with
formation of the stable five-membered ring containing nitrogen-Pd
and C(phenyl)-Pd bonds. [15e24] Palladacycles containing alkyl C
(sp3)-Pd bonds can also be prepared either when the aromatic
position is unavailable or sterically hindered. [25e29] or even when
* Corresponding author. Tel.: þ34 981 563100; fax: þ34 981 597525.
** Corresponding author.
E-mail addresses: qiluaafl@udc.es (A. Fernández), josemanuel.vila@usc.es (J.M.
Vila).
0022-328X/$ e see front matter Ó 2010 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2010.09.071

D. Vázquez-García et al. / Journal of Organometallic Chemistry 696 (2011) 764e771
765
structure, which to the best of our knowledge is the first example of
such behaviour in the reactivity of palladacylces, and also, dinuclear
six-membered metallacycles with bridging diphosphines.
The diphosphine Ph2PCH2PPh2 (dppm) reacts with palladium
cyclometallated complexes coordinating as a chelating [38,40,
46,48e58] or bridging ligand; [40,41,47,49,51,52,54,59e67] the
complex/dppm molar ratio being the factor that determines the
coordination mode. In the latter case the “bite” of the diphosphine
is short enough to allow, in some cases, coordination of a second
bridging ligand between the palladium atoms, e.g., halide or acetate
anions.[41,46,48,50,55] In some cases both types of complexes may
be easily interconverted [47]. However, when the cyclometallated
ligand is strongly bonded to the palladium atom, as for example
terdentate [C,N,S] ligands which give stable fused rings at the metal
centre and leave only one coordination position available, dppm
may also act as monodentate even when large amounts of this
ligand are used. [52,56,59,68,69] In other cases the diphosphine
2. Results and discussion
For the convenience of the reader the compounds and reactions
are shown in Scheme 1. The compounds described in this paper
were characterised by elemental analysis (C, H, N), and IR and 1H
and 31P-{1H} spectroscopy (see experimental section) and, in part,
by mass spectrometry and X-ray single crystal diffraction. The
preparation of complexes 1a, 2a, 1a0 and 2a0 has been described
previously by us [37]; their NMR and IR spectra are included in the
experimental section for comparative purposes.
Ph2
P
Ph2
P
Ph2
P
Pd
R
X
Ph2
P
Pd
Pd
Pd
X
N
N
[X]
[PF6]
P
N
N
P
Ph2
Ph2
5a´ X = Cl, R = CH2
6a´ X = Cl, R = CCH2
7a´ X = Br, R = CH2
5a X = Cl
6a X = Br
iii
ii
4
3
2
Meb
5
6
Cl
X
Mea
1
Pd
Pd
2
2
N
N
7
Mec
Mee
12
11
8
9
10
Med
1a' X = Cl
2a' X = Br
1a X = Cl
2a X = Br
i
i
Ph2
P
Ph2
P
Pd
[PF6]
[PF6]
Pd
N
R
N
P
Ph2
P
Ph2
3a´ R = CH2
4a´ R = CCH2
3a R = CH2
4a R = CCH2
Scheme 1. (i) dppm or vdpp (1:2 M ratio), NH4PF6, acetone/water; (ii): dppm or vdpp, NH4PF6, acetone/water; (iii) dppm or vdpp (1:1 M ratio), acetone.

766
D. Vázquez-García et al. / Journal of Organometallic Chemistry 696 (2011) 764e771
remains as monodentate after opening of the cyclometallated ring,
[70] and consequently gives rise to non-cyclometallated complexes.
In any case, the free phosphorus atom of dppm keeps its coordi-
nation potential, and complexes in which it is bonded to a second
metal atom have also been reported. [42,68,69] Also, examples in
which two dppm ligands are simultaneously coordinated to the
metal centre as monodentate and chelating ligands are known.
[42,70]
compared to the uncoordinated ligand), and the PCH2P resonance
appeared as two multiplets indicating the diastereotopic nature of
the two protons as a consequence of the A-frame structure (vide
infra).
In order to clarify these observations we then treated 1a with
dppm in deuterated chloroform in an NMR tube reaction. When
a 1a/dppm 1:1 M ratio was used, complexes 5a and 3a were
obtained in an approximately equimolar ratio. However for a 1a/
dppm 1:2 M ratio, the relative proportion 3a/5a was 1/2. Different
reaction times did not produce significant changes. A similar
behaviour was observed in the reaction of 2a with dppm, which
gave rise to 6a, similar to 5a, but bearing m-bromine between the
two palladium atoms.
However, treatment of 1a or 2a with Ph2PC(]CH2)PPh2 (vdpp)
afforded 4a, in all conditions tested, with vdpp as a chelating
ligand, similar to 3a; no indication of an analogue to 5a or 6a was
observed.
Thus, reaction of 1a with Ph2PCH2PPh2 (dppm) and ammonium
hexafluorophosphate in acetone gave [Pd{2,5-Me2C6H2C(H)]N
(2,4,6-Me3C6H2)-C6,N}(Ph2PCH2PPh2-P,P)][PF6] 3a, after recrystal-
lization with the diphosphine coordinated in a chelating fashion.
The MS-FAB spectrum showed the corresponding peaks assigned
to [(L-H)Pd(dppm)]þ, which were characteristic clusters of isotopic
peaks covering ca. 10 m/z units, due to the presence of the
numerous palladium isotopes (see Experimental). The 1H NMR
spectrum showed the HC]N resonance coupled to the 31P nucleus
trans to the imine nitrogen (
d
8.32 ppm; 4JHP ¼ 8.1 Hz). The signal
Treatment of 1a0 or 2a0 with Ph2PCH2PPh2 (dppm) or Ph2PC(]
CH2)PPh2 (vdpp) in 1:2 M ratio gave the mononuclear complexes 3a0
and 4a0, respectively. The 1H NMR spectra showed the HC]N reso-
nanceas a doublet(ca. 7.75 ppm), bycoupling tothe31P nucleustrans
to nitrogen; the signal assigned to the metallated eCH2- group was
a doublet of doublets (3.40 and 3.50 ppm for 3a0 and 4a0, respec-
tively) by coupling to both phosphorus atoms of the diphosphine
assigned to the PCH2P protons was a multiplet at 4.10 ppm. The 31P-
{1H} NMR spectrum showed two doublets for the two non-equiv-
alent phosphorus nuclei (
d
ꢀ 12.58, ꢀ 33.12 ppm; JPP ¼ 73.4 Hz);
the resonance at lower frequency was assigned to the phosphorus
nucleus trans to the phenyl carbon atom in accordance with the
higher trans influence of the latter with respect to the C]N
nitrogen atom. [71] The 31P chemical shifts were clearly influenced
by the four-membered ring size, [72] which gave a negative DR and
an upfield shift of the resonances.
ligand. In the 31P-{1H} NMR spectra two doublets were assigned to
2
the non-equivalent phosphorus atoms (
d
¼ ꢀ4.06, ꢀ26.37 ppm; J
(PP) ¼ 63.7 Hz for 3a0 and
d
¼ 1,27 and 13.10 ppm; 2J(PP) ¼ 19,7 Hz
Recrystallization of the final product of the reaction between 1a
and dppm from a chloroform/hexane solution gave an altogether
new compound, for which the elemental analyses of the novel
species was in accordance with [{Pd[2,5-Me2C6H2C(H)]N(2,4,6-
for 4a0).
The reaction of 1a0 with Ph2PCH2PPh2 (dppm) or Ph2PC(]CH2)
PPh2 (vdpp) and of 2a0 with dppm in 1:1 M ratio, gave the novel
dinuclear cyclometallated complexes 5a0, 6a0 and 7a0, respectively,
bearing six-membered metallacycles. The 1H NMR spectra of the
complexes showed the methylene proton resonance as a broad
signal at 2.58, 2.81and 2.69 ppmfor 5a0, 6a0 and 7a0, respectively. The
31P-{1H} NMR showed a singlet resonance for the phosphorus nuclei
indicating the symmetric nature of complexes. The specific molar
conductivities in dry acetonitrile were close to the values expected
for 1:1 electrolytes [73] and, therefore, the ionic formulation
was preferred to the neutral one usual in this type of complexes.
Me3C6H2)-C6]}2(m-Ph2PCH2PPh2)2(m-Cl)][PF6] 5a, a compound with
a peculiar A-frame structure. The 31P-{1H} NMR spectrum showed
a singlet resonance at 8.43 ppm, indicating the equivalence of the
four phosphorus atoms. The IR spectrum of the complex showed
the n
(C]N) band at 1632 cmꢀ1, close to its position in the spectrum
of the free ligand, in accordance with absence of PdeN bonding. In
the 1H NMR spectra the signal assigned to the HC]N resonance
was a singlet at 9.75 ppm (lowfield shifted by more than 1 ppm as
Table 1
Crystal data and structure refinement for complexes 3a, 4a, 5a, and 6a0.
Formula
3a
4a
5a
6a0
C43H42F6NP3Pd
C44H42F6NP3Pd
C90.50H92.50Cl14.50F6N2O2P5Pd2
C65H73Cl2N2O2.5P2Pd2
FW
886.09
Monoclinic
P21/n
13.435(5)
14.467(5)
21.124(5)
898.1
Monoclinic
P21/n
13.809(5)
14.849(5)
20.636(5)
2235.84
Triclinic
P-1
1267.89
Monoclinic
P21/c
13.808(1)
15.142(2)
30.786(4)
Crystal system
Space group
a/Å
b/Å
c/Å
15.065(5)
16.715(5)
20.883(5)
80.505(5)
72.032(5)
77.104(5)
8412(4)
2
ꢁ
ꢁ
ꢁ
a
/
b
/
97.610(5)
98.267(5)
101.638(1)
g
/
V/Å3
4070(2)
4
4187(2)
4
6304.6(1)
4
Z
m
[mmꢀ1
]
0.633
0.616
0.912
0.749
max., min.
transmissions
q
0.83, 0.74
1.70 to 28.27
30824
0.92, 0.76
1.67to 28.36
61752
0.96, 0.85
1.03 to 28.36
86057
0.75, 0.68
1.35 to 28.30
43693
range/ꢁ
Reflections collected
Reflections unique
Rint
9904
10442
24059
15332
0.0222
0.0326
0.1200
0.0555
0.0398
0.1395
0.1193
0.0771
0.2661
0.0280
0.0576
0.1674
a
R1
b
wR2
a
R1 ¼ SkFoj-jFck/SjFoj, [F > 4
s(F)].
b
wR2 ¼ [S[w(F2o-Fc2)2/Sw(Fo2)2]1/2, all data.

D. Vázquez-García et al. / Journal of Organometallic Chemistry 696 (2011) 764e771
767
Table 2
selected bond lengths (Å) and angles (ꢁ) for complexes 3a and 4a.
3a
4a
3a
80.7(1)
100.8(1)
71.2(1)
107.3(1)
174.4(1)
171.9(1)
96.0(1)
4a
80.7(1)
99.8(1)
72.1(1)
107.5(1)
175.7(1)
171.5(8)
Pd(1)-C(6)
Pd(1)-N(1)
Pd(1)-P(1)
Pd(1)-P(2)
C(31)-C(32)
2.085(2)
2.067(2)
2.299(1)
2.384(1)
2.087(3)
2.064(3)
2.293(1)
2.378(1)
1.309(5)
C(6)-Pd(1)-N(1)
N(1)-Pd(1)-P(2)
P(2)-Pd(1)-P(1)
P(1)-Pd(1)-C(6)
C(6)-Pd(1)-P(2)
N(1)-Pd(1)-P(1)
P(2)-C(43)-P(1)
P(2)-C(31)-P(1)
98.3(2)
2.1. Crystal structures 3a, 4a, 5a and 6a0
Suitable crystals of the title compounds were grown from slowly
evaporating chloroform (3a and 4a) chloroform/n-hexane (5a), and
acetone/n-hexane (6a0) solutions. Crystallographic data and
selected interatomic distances and angles are listed in Tables 1e3
and the labelling schemes for the compounds are shown in
Figs. 1e5 (3a, Fig. 1; 4a, Fig. 2; 5a, Figs. 3 and 4; 6a0, Fig. 5). The
crystals consist of discrete molecules, separated by normal van der
Waals distances. The crystal structures of 5a, 3a and 4a comprise
one cationic complex per asymmetric unit and a hexafluoro-
phosphate anion and, for compound 5a, four and a half of chloro-
form solvent molecules. The asymmetric unit of 6a0 comprises one
complex cation, one chloride anion and an acetone solvent
molecule.
Fig. 1. Cation of [Pd{2,5-Me2C6H2C(H)]N(2,4,6-Me3C6H2)-C6,N}(Ph2PCH2PPh2-P,P)]
[PF6] (3a), with labelling scheme. Hydrogen atoms have been omitted for clarity.
The palladium atom in complexes 3a and 4a is bonded to
four atoms: the C(6) carbon atom, the imine nitrogen N(1) of the
Schiff base ligand, and two phosphorus atoms from a chelating
Ph2PCH2PPh2 (dppm, 3a) or Ph2PC(¼CH2)PPh2 (vdpp, 4a), in
a slightly distorted square-planar coordination environment. The
sum of angles about palladium atoms is approximately 360ꢁ, with
the distortions more noticeable in the somewhat reduced “bite”
angles consequent upon chelation. The requirements of the five and
four-membered metallated chelate rings strongly distorts the bond
angles C(6)-Pd(1)-N(1) [80.7(1)ꢁ and 80.7(1)ꢁ A for 3a and 4a,
respectively] and P(1)-Pd(1)-P(2) [71.2(1)ꢁ and 72.1(1)ꢁ for 3a and
4a, also respectively]. The P(1)-C-P(2) bond angles of 96.0(1)ꢁ (3a)
and 98.3(2)ꢁ (4a) are shorter than the expected values for a sp3 and
sp2 carbons and also smaller than those found in free dppm, 106.4ꢁ,
or vdpp,118.4ꢁ, ligands. [74,75] The Pd(1)-N(1) and Pd(1)-C(6) bond
lengths (ca. 2.06 A and ca. 2.08 A, respectively) reflects the trans
influence of the phosphorus atom and are similar to values repor-
ted previously [40,42e44]. Analogously, the trans influence of the
metallated C(6) carbon is clearly illustrated by the larger Pd(1)-P(2)
distance trans to carbon as compared to the Pd(1)-P(1) distance
trans to nitrogen (ca. 2.38 A vs. 2.29 A, see Table 2). For complex 4a,
the C(31)-C(32) bond distance is 1.309(5) A, which is within the
range expected for a carbonecarbon double bond and is shorter
than the value of 1.34 A in free vdpp. [75]
In complex 5a the characteristic A-frame structure of the cation
may be described as formed by two approximately square-planar
palladium atoms bonded through two dppm and one chlorine
bridging ligands. The coordination sphere at the metal centre is
completed by the metallated carbon atom. The two coordination
planes are at angle of 86ꢁ, and the maximum distortion from the
ideal 90ꢁ corresponds to the C(1)-Pd(2)-P(2) angle of 94.2(1)ꢁ. The
eight-membered Pd(m-PCH2P)2Pd ring adopts a pseudo-boat
conformation, with the two methylene groups and the bridging
chlorine lying on opposite faces of the Pd2P4 plane. The metallated
Table 3
Structural data for 5a and 6a0.
5a
6a0
5a
5a
6a0
6a0
Pd(1)-C(24)
Pd(2)-C(6)
Pd(1)-Cl(1)
Pd(2)-Cl(1)
Pd(1)-P(3)
Pd(1)-P(4)
Pd(2)-P(1)
Pd(2)-P(2)
Pd(1)-C(1)
Pd(1)-N(1)
Pd(1)-P(1)
Pd(1)-Cl(1)
Pd(2)-C(45)
Pd(2)-N(2)
Pd(2)-P(2)
Pd(2)-Cl(1)
C(19)-C(20)
2.020(7)
2.037(7)
2.409(2)
2.426(2)
2.325(2)
2.334(2)
2.324(2)
2.362(2)
C(6)-Pd(2)-P(1)
P(1)-Pd(2)-Cl(1)
Cl(1)-Pd(2)-P(2)
P(2)-Pd(2)-C(6)
C(6)-Pd(2)-Cl(1)
P(1)-Pd(2)-P(2)
C(24)-Pd(1)-P(3)
P(3)-Pd(1)-Cl(1)
Cl(1)-Pd(1)-P(4)
P(4)-Pd(1)-C(24)
C(24)-Pd(1)-Cl(1)
P(3)-Pd(1)-P(4)
Pd(1)-Cl(1)-Pd(2)
P(1)-C(38)-P(3)
P(2)-C(37)-P(4)
88.9(2)
87.1(1)
94.2(1)
88.9(2)
171.4(2)
171.0(1)
88.5(29
91.8(1)
90.4(1)
90.0(2)
174.2(2)
172.2(1)
88.3(1)
120.1(4)
118.0(4)
Pd(1)-Cl(1)-Pd(2)
C(1)-Pd(1)-N(1)
N(1)-Pd(1)-Cl(1)
Cl(1)-Pd(1)-P(1)
P(1)-Pd(1)-C(1)
C(1)-Pd(1)-Cl(1)
N(1)-Pd(1)-P(1)
C(45)-Pd(2)-N(2)
N(2)-Pd(2)-Cl(1)
Cl(1)-Pd(2)-P(2)
P(2)-Pd(2)-C(45)
C(45)-Pd(2)-Cl(1)
N(2)-Pd(2)-P(2)
P(2)-C(19)-P(1)
119.2(1)
82.7(2)
87.6(1)
94.12(4)
95.7(1)
169.9(1)
174.7(1)
83.3(2)
88.87(12)
92.08(4)
95.8(2)
172.1(2)
178.4(1)
116.4(3)
2.047(5)
2.120(4)
2.261(1)
2.431(1)
2.035(5)
2.138(4)
2.265(1)
2.426(1)
1.305(7)

768
D. Vázquez-García et al. / Journal of Organometallic Chemistry 696 (2011) 764e771
Fig. 4. Cation of [{Pd[2,5-Me2C6H2C(H)]N(2,4,6-Me3C6H2)-C6]}2(m-Ph2PCH2PPh2)2(m-
Cl)][PF6] (5a), with labelling scheme. Phosphine phenyl rings and hydrogen atoms have
been omitted for clarity.
probably due to steric requirements to form the main core of the
A-frame structure.
The cation of complex 6a0 may be described as a dinuclear
complex in which two palladium atoms are connected by one vdpp
and one chlorine bridging ligands defining a six-membered ring
with a chair-like geometry. The six-membered cyclometallated
rings share the palladium atoms with the, also six-membered, core
bridging ring. The square-planar geometry about the palladium
atoms is slightly distorted due to the chelation of the Schiff base
[angles C(1)-Pd(1)-N(1) of 82.7(2)ꢁ and C(45)-Pd(2)-N(2) of 83.3ꢁ
(2)]. The angle between the coordination planes is 43.3ꢁ.
The Pd(1)-Cl(1)-Pd(2) angle in the chlorine bridge of 119.2(1)ꢁ is
larger than those found in complexes 1a and 1a0. [37] The angle P
(1)-C(19)-P(2) corresponding to the vdpp bridging diphosphine of
116.4(3)ꢁ is close to the expected 120ꢁ of a sp2 carbon and to the
118.4ꢁ found in the uncoordinated vdpp, and in similar complexes
Fig. 2. Cation of [Pd{2,5-Me2C6H2C(H)]N(2,4,6-Me3C6H2)-C6,N}{Ph2PC(]CH2)PPh2-
P,P}][PF6] (4a), with labelling scheme. Hydrogen atoms have been omitted for clarity.
phenyl rings are coplanar (angle between planes 6.7ꢁ) and lie
almost perpendicular to the Pd2P4 plane, presumably in order to
minimize repulsions between these rings and the phenyl rings of
the dppm ligands.
The Pd(1)-Cl(1)-Pd(2) angle in the chlorine bridge of 88.3(1)ꢁ is
similar to the values found in the halide-bridged complexes 1a and
1a0 [84.1(1) and 92.1(4)ꢁ, respectively]. The PeCeP angles of the
dppm ligands are 120.1(4)ꢁ and 118.0(4)ꢁ, larger than the value of
106.4ꢁ reported for the uncoordinated dppm ligand, [74,75] and
even larger than the value of 109.5ꢁ expected for a sp3 carbon,
[46] indicating little strain of the six-membered Pd(m-PCP)(m-Cl)Pd
ring. This was confirmed by the value of 128.3ꢁ (close to the cor-
responding in 6a0) found in a related complex with vdpp as
bridging ligand and two PdeCl terminal bonds instead of the
PdeClePd bridging unit. [76]
Fig. 5. Cation of [{Pd[1-CH2-2-{HC]N(2,4,6-Me3C6H2)}-4-MeC6H3-C,N]}2{
(¼CH2)PPh2}(
-Cl)][Cl] (6a0), with labelling scheme. Hydrogen atoms have been
omitted for clarity.
m-Ph2PC
Fig. 3. Cation of [{Pd[2,5-Me2C6H2C(H)]N(2,4,6-Me3C6H2)-C6]}2(
Cl)][PF6] (5a), with labelling scheme. Hydrogen atoms have been omitted for clarity.
m
-Ph2PCH2PPh2)2(
m
-
m

D. Vázquez-García et al. / Journal of Organometallic Chemistry 696 (2011) 764e771
769
3. Conclusion
CH2], 2.40 [6H, s, Mec, Med], 2.22, 2.20 [6H, s, Meb, Mee]. MS-FAB: m/
z ¼ 793 [(L-H)2Pd2Br]þ.
A series of mononuclear and dinuclear C(sp2)-Pd and C(sp3)-Pd
bonded palladacycles with the Schiff base ligand a, bearing tertiary
diphosphines, have been synthesized. Having put forward the
versatile behaviour of the ligand in a previous report from this
laboratory, which showed the preparation of five- and six-
membered metallacycles, their reactivity towards nucleophiles such
as tertiary diphosphines remained outstanding. Therefore, dinu-
clear and mononuclear systems have been prepared, with bridging
and chelating diphosphines, respectively, which in the former case
show the differing bonding possibilities of the diphosphine/halogen
bridging system connecting the metal centers. Thus, the crystal
structure of complex 5a shows the unique A-frame disposition with
three ligands spanning across the metal centers: two diphosphines
and one halogen atom, in an unprecedented arrangement; whereas,
the dinuclear metallacycle, complex 6a0, presents as its most salient
feature the three six-membered rings linked by the two palladium
atoms.
4.2.5. [Pd{2,5-Me2C6H2C(H)]N(2,4,6-Me3C6H2)-C6,N}
(Ph2PCH2PPh2-P,P)][PF6] 3a
Ph2PCH2PPh2 (0.029 g, 0.075 mmol) was added to a suspen-
sion of 1a (0.026 g, 0.037 mmol) in acetone (10 cm3). The
mixture was stirred for 30 min at room temperature, after which
an excess of ammonium hexafluorophosphate was added. The
mixture was stirred for a further 1 h, the complex precipitated
out by addition of water, filtered off and dried in vacuo, to give
the final compound as a pale yellow solid which was recrystal-
lized from acetone/hexane. Yield: 50%. Anal. Found: C, 58.4; H,
4.7; N, 1.5; C43H42NF6P3Pd requires C, 58.3; H, 4.8; N, 1.6%. IR:
(C]N) 1571 cmꢀ1. RMN 1H (300 MHz, CDCl3,
ppm, J Hz):
¼ 8.32 [1H, d, JP,H 8.1, HCN], 6.46 [1H, s, H9, H11], 4.10 [2H, m,
PCH2P], 2.47 [3H, s, Me], 2.22 [6H, s, Me], 2.13 [3H, s, Me], 1.81
n
d
d
[3H, s, Me]. 31P-{1H} NMR (211.49 MHz, CDCl3,
d
ppm): ꢀ12.58 [d,
2JP,P 73.4, Ptrans-N], ꢀ33.21 [d, Ptrans-C]. MS-FAB: m/z ¼ 740 [(L-H)
Pd(dppm)]þ.
4. Experimental section
4.2.6. [Pd{2,5-Me2C6H2C(H)]N(2,4,6-Me3C6H2)-C6,N}{Ph2PC(]CH2)
PPh2-P,P}][PF6] 4a
4.1. General Remarks
Ph2PC(]CH2)PPh2 (0.030 g, 0.076 mmol) was added to
a suspension of 1a (0.030 g, 0.038 mmol) in acetone (10 cm3). The
mixture was stirred for 30 min at room temperature, after which an
excess of ammonium hexafluorophosphate was added. The mixture
was stirred for a further 1 h, the complex precipitated out by
addition of water, filtered off and dried in vacuo, to give the final
product as a pale yellow solid. Yield: 93%. Anal. found: C, 58.3; H,
Solvents were purified by standard methods. [77] Chemicals
were reagent grade. Microanalyses were carried out using a Carlo
Erba Elemental Analyser, Model 1108. IR spectra were recorded as
Nujol mulls or polythene discs Nujol mulls or KBr discs on a Satel-
lite FTIR. NMR spectra were obtained as CDCl3 solutions and
referenced to SiMe4 (1H, 13C-{1H}) or 85% H3PO4 31P-{1H}) and
(
4.6; N, 1.5; C44H42NF6P3Pd requires C, 58.4; H, 4.7; N, 1.6%. IR:
n
(C]
were recorded on a Bruker AV-300F spectrometer. All chemical
shifts were reported downfield from standards. The FAB mass
spectra were recorded using a FISONS Quatro mass spectrometer
with a Cs ion gun; 3-nitrobenzyl alcohol was used as the matrix.
Ligand a and the compounds 1a, 2a, 1a0 and 2a0 were prepared as
previously reported by us. [37]
N) 1612 s cmꢀ1. RMN 1H (300 MHz, CDCl3,
d
ppm, J Hz):
d
¼ 8.30 [1H,
4
dd, JH,P 8.8, JH,P 8.16, HCN], 6.44 [1H, s, H9,H11], 6.18 [2H, m, C]
CH2], 2.48 [3H, s, Me], 2.22 [6H, s, Me], 2.10 [3H, s, Me], 1.86 [3H, s,
Me]. 31P-{1H} NMR (211.49 MHz, CDCl3, ppm): 1.78 [1P, d, 2JP,P 11.5,
d
Ptrans-N], ꢀ 5.08 [1P, d, Ptrans-c]. MS-FAB: m/z ¼ 752 [(L-H)Pd
(vdpp)]þ.
4.2. Synthesis of the cyclopalladated complexes
4.2.7. [Pd{1-CH2-2-[HC]N(2,4,6-Me3C6H2)]-4-MeC6H3-C,N}
(Ph2PCH2PPh2-P,P0)][PF6] 3a0
4.2.1. [Pd{2,5-Me2C6H2C(H)]N(2,4,6-Me3C6H2)-C6,N}(
m
-Cl)]2 1a
Compound 3a0 was obtained as a pale yellow solid, following
a similar procedure to the one used in the synthesis of 4a but using
1a0 and dppm as starting materials.
IR:
n
(C]N) 1594 s cmꢀ1. RMN 1H (300 MHz, CDCl3,
d ppm, J Hz):
d
¼ 8.02 [s, 1H, HCN], 6.70 [m, 4H, H3, H4, H9, H11], 2.37, 2.30 [6H, s,
Mea, Meb], 2.27 [6H, s, Mec, Mee], 1.61 [3H, s, Med]. MS-FAB:
Yield: 70%. Anal. found: C, 58.0; H, 5.0; N, 1.5; C43H42NF6P3Pd
m/z ¼ 749 [(L-H)2Pd2Cl]þ.
requires C, 58.3; H, 4.8; N, 1.6%. IR:
(300 MHz, CDCl3, ppm, J Hz):
n
(C]N) 1610 s cmꢀ1. RMN 1H
¼ 7.76 [1H, s, JH,P 8.1, HCN], 7.01,
d
d
3
4.2.2. [Pd{1-CH2-2-[HC]N(2,4,6-Me3C6H2)]-4-MeC6H3-C,N}(
m
d
-
6.94 [2H, d, J3,4 7.0, H3/H4], 6.97 [1H, s, H6], 6.75 [2H, br, H9], 4.04
[2H, dd, 2JH,P 11.6, 7.4, PCH2P], 3.40 [2H, dd, 2JH,H 10.5, 1.6, CH2], 2.40,
Cl)]2 1a0
IR:
J Hz):
n
(C]N) 1610 s cmꢀ1. RMN 1H (300 MHz, CDCl3,
ppm,
2.21, 2.20 [12H, s, Me]. 31P-{1H} NMR (211.49 MHz, CDCl3,
d ppm):
d
¼ 7.46 [1H, s, HCN], 7.26 [1H, d, 3J3,4 7.8, H3], 7.09 [1H, dd, 3J3,4
ꢀ4.06 [1P, d, 2J(PP) ¼ 63,7, PtransꢀN], ꢀ26.37 [1P, d, PtransꢀC]. MS-FAB:
0.9, H4], 6.99 [1H, d, H6], 6.89 [2H, br, H9], 3.38 [2H, br, CH2], 2.38
[6H, br, Mec, Med], 2.29, 2.21 [6H, s, Meb, Mee]. MS-FAB: m/z ¼ 784
[(L-H)2Pd2Cl2]þ.
m/z ¼ 740 [(L-H)Pd(dppm)]þ.
4.2.8. [Pd{1-CH2-2-[HC]N(2,4,6-Me3C6H2)]-4-MeC6H3-C,N}
{Ph2PC(]CH2)PPh2-P,P}][PF6] 4a0
4.2.3. [Pd{2,5-Me2C6H2C(H)]N(2,4,6-Me3C6H2)-C6,N}(
IR:
(C]N) 16014 s cmꢀ1. RMN 1H (300 MHz, CDCl3,
J Hz):
m
-Br)]2 2a
Compound 4a0 was obtained as a pale yellow solid, following
a similar procedure to the one used in the synthesis of 4a but using
2a0 as starting material.
n
d
ppm,
d
¼ 8.02 [s, 1H, HCN], 6.74 [4H, m, H3, H4, H9, H11], 2.37 [s, 6H,
Mea, Meb], 2.27 [s, 9H, Mec, Mee, Med]. MS-FAB: m/z ¼ 793
Yield: 66%. Anal. found: C, 58.4; H, 4.9; N, 1.6; C44H42NF6P3Pd
[(L-H)2Pd2Br]þ.
requires C, 58.8; H, 4.7; N, 1.6%. IR: n
(C]N) 1605 s cmꢀ1. RMN 1H
(300 MHz, CDCl3,
6.92 [2H, d, J3,4 7.0, H3/H4], 6.95 [1H, s, H6], 6.69 [2H, br, H9], 6.18
d
ppm, J Hz):
d
¼ 7.75 [1H, d, 4JH,P 12.2, HCN], 6.97,
3
4.2.4. [Pd{1-CH2-2-[HC]N(2,4,6-Me3C6H2)]-4-MeC6H3-C,N}(
m
-
2
Br)]2 2a0
[2H, m, C]CH2], 3.50 [2H, dd, JH,P 10.4, 4.0, CH2], 2.35, 2.28, 2.19
IR:
¼ 7.49 [1H, s, HCN], 7.07 [1H, d, J3,4 7,5, H3], 6.98 [1H, d, J6,4 0.8,
H6], 6.89 [2H, br, H9, H11], 6.85 [1H, dd, J6,4 0,8, H4], 3.37 [2H, br,
n
(C]N) 1605 s cmꢀ1. RMN 1H (300 MHz, CDCl3,
d
ppm, J Hz):
[12H, s, Me]. 31P-{1H} NMR (211.49 MHz, CDCl3,
d ppm): 1.27 [1P, d,
4
d
2JP,P 19.7, PtransꢀN],13.10 [1P, d, PtransꢀC]. MS-FAB: m/z ¼ 752 [(L-H)Pd
(vdpp)]þ.

770
D. Vázquez-García et al. / Journal of Organometallic Chemistry 696 (2011) 764e771
4.2.9. [{Pd[2,5-Me2C6H2C(H)]N(2,4,6-Me3C6H2)-C6]}2(
Ph2PCH2PPh2)2( -Cl)][PF6] 5a
m
-
[2H, br, CH2], 2.36, 2.28, 2.17 [12H, s, Me]. 31P-{1H} NMR
m
(211.49 MHz, CDCl3,
d
ppm):29.25 (s). MS-FAB: m/z ¼ 1177
Ph2PCH2PPh2 (0.048 g, 0.125 mmol) was added to a suspension of
2a (0.049 g, 0.062 mmol) in acetone (15 cm3). The mixture was
stirred for 24 h at room temperature after which an excess of
ammonium hexafluorophosphate was added. The mixture was
stirred for 1 h and a yellow solid precipitated by addition of water,
which was filtered off, dried and recrystallized form chloroform/
hexane. Yield: 35%. Anal. found: C, 51.0; H, 4.2; N, 1.1;
[(L-H)2Pd2(dppm)(Br)]þ. Specific molar conductivity,
L
m
¼
160.2 Uꢀ1 cm2 molꢀ1 (in acetonitrile).
4.3. X-ray crystallographic studies
Three-dimensional, room temperature X-ray data were
collected on a Bruker Smart 1k CCD and a Bruker X8 Apex dif-
fractometeres using graphite-monochromated Mo-Ka radiation. All
C86H84N2F6ClP5Pd2(CHCl3)4 requires C, 50.0; H, 4.0; N,1.3%. IR:
n
(C]
N) 1632s, y d ppm, J Hz):
(PdeCl) 281 cmꢀ1. RMN 1H (300 MHz, CDCl3,
the measured reflections were corrected for Lorentz and polar-
isation effects and for absorption by semi-empirical methods based
on symmetry-equivalent and repeated reflections. The structures
were solved by direct methods and refined by full matrix least
squares on F2. Hydrogen atoms were included in calculated posi-
tions and refined in riding mode. Chloroform solvent molecules in
the crystal of complex 5a were poorly defined and the Cl(7), Cl(8)
and Cl(9) chlorine atoms of one of them were disordered and,
consequently, refined in two complementary positions with occu-
pancies of 60 and 40%. [78] Disorder in the hexafluorophosphate
ions affected to the F(1)-F(6) fluorine atoms of 3a and F(3)-F(6)
atoms of 4a. The refinement was carried out taking into account
two components of the disorder and occupancies of approximately
73e27% and 55e45% were assigned to the anions of 3a and 4a,
respectively. Refinement converged with allowance for thermal
anisotropy of all non-hydrogen atoms. The structure solution
and refinement were carried out using the program package
SHELX-97 [79].
d
¼ 9.75 [1H, s, HCN], 6.52 [2H, s, H9, H11], 6.11, 5.93 [2H, d, 3J3,4 7.5, H3,
H4], 4.39, 3.83 [4H, m, -CH2-], 2.69 [3H, s, Me], 2.34 [6H, s, Me], 2.21
[6H, s, Me]. 31P-{1H} NMR (211.49 MHz, CDCl3,
d ppm): 8.43 (s).
4.2.10. [{Pd[2,5-Me2C6H2C(H)]N(2,4,6-Me3C6H2)-C6]}2(
m-
Ph2PCH2PPh2)2( -Br)][PF6] 6a
m
Complex 6a was prepared as a yellow solid following a similar
procedure to the one used in the synthesis of 5a. Yield: 40%. Anal.
found: C, 50.0; H, 3.8; N, 1.3; C86H84N2F6BrP5Pd2(CHCl3)4 requires C,
49.0; H, 3.9; N, 1.3%. IR:
(300 MHz, CDCl3, ppm, J Hz):
n (C]N) 1628s, y
(PdeCl) 285 cmꢀ1. RMN 1H
d
d
¼ 9.77 [1H, s, HCN], 6.45 [2H, s, H9,
3
H11], 6.08, 5.95 [2H, d, J3,4 7.5, H3, H4], 4.44, 3.70 [4H, m, -CH2-],
2.72 [3H, s, Me], 2.35 [6H, s, Me], 2.21 [6H, s, Me]. 31P-{1H} NMR
(211.49 MHz, CDCl3,
d ppm): 8.57 (s).
4.2.11. [{Pd[1-CH2-2-{HC]N(2,4,6-Me3C6H2)}-4-MeC6H3-C,N]}2(
m-
Ph2PCH2PPh2)(
m
-Cl)][Cl] 5a0
Ph2PCH2PPh2 (0.029 g, 0.075 mmol) was added to a suspension
of 1a0 (0.059 g, 0.075 mmol) in acetone (15 cm3). The mixture was
stirred for 12 h at room temperature and the solvent removed to
give a yellow solid which was recrystallized from dichloromethane/
hexane.
Acknowledgements
We thank the Xunta de Galicia (Ref. PGIDIT04PXI10301IF and
INCITE07PXI103083ES) for financial support.
Yield: 70%. Anal. Found: C, 59.7; H, 5.1; N, 2.1;
C61H62N2Cl2P2Pd2(H2CCl2) requires C, 59.4; H, 5.1; N, 2.2%. IR:
n
(C]
Appendix A. Supplementary material
N) 1605s, y d ppm, J Hz):
(PdeCl) 288 cmꢀ1. RMN 1H (300 MHz, CDCl3,
d
¼ 6.99 [1H, s, H6], 6.92 [1H, d, 3J3,4 7.7, H4], 6.85 [1H, br, H9], 6.30 [1H,
CCDC-718091;718093;718090;718092 contains the supple-
mentary crystallographic data for 3a, 4a, 5a and 6a0 respectively.
These data can be obtained free of charge from The Cambridge
Crystallographic Data Centre via http://www.ccdc.cam.ac.uk/data_
request/cif.
d, H3], 2.58 [2H, br, CH2], 2.35, 2.28, 2.21 [12H, s, Me]. 31P-{1H}
NMR (211.49 MHz, CDCl3,
d ppm): 30.04 (s). MS-FAB: m/
z ¼ [(L-H)2Pd2(dppm)(Cl)]þ. Specific molar conductivity, L
¼
m
140.1 Uꢀ1 cm2 molꢀ1 (in acetonitrile).
4.2.12. [{Pd[1-CH2-2-{HC]N(2,4,6-Me3C6H2)}-4-MeC6H3-
References
C,N]}2{m-Ph2PC(]CH2)PPh2}(m
-Cl)][Cl] 6a0
Compound 6a0 was obtained as a pale yellow solid, following
a similar procedure to the one used in the synthesis of 5a0 but using
vdpp as starting material.
[1] M. Pfeffer, J.P. Sutter, M.A. Rottevel, A. de Cian, J. Fischer, Tetrahedron 48
(1992) 2427.
[2] A.D. Ryabov, R. van Eldik, G. Le Borgne, M. Pfeffer, Organometallics 12 (1993)
1386.
Yield: 75%. Anal. found: C, 59.7; H, 5.1; N, 2.1;
[3] B.S. Wild, Coord. Chem. Rev. 166 (1997) 291.
C61H62N2Cl2P2Pd2(H2CCl2) requires C, 59.4; H, 5.1; N, 2.2%. IR:
n
(C]
[4] S.Y.M. Chooi, P.H. Leung, C.C. Lim, K.F. Mok, G.H. Quek, K.Y. Sim, et al.,
Tetrahedron: Asymmetry 3 (1992) 529.
[5] P. Espinet, M.A. Esteruelas, L.A. Oro, J.L. Serrano, E. Sola, Coord. Chem. Rev. 17
(1992) 215.
[6] C. Navarro-Ranninger, I. López solera, J. Rodríguez, J.L. García-Ruano,
P.R. Raithby, J.R. Masaguer, et al., Med. Chem. 36 (1993) 3795.
[7] C. Navarro-Ranninger, I. López-Solera, V.M. Gonzalez, J.M. Pérez, A. Alvarez-
Valdés, A. Martin, et al., Inorg. Chem. 35 (1996) 5181.
[8] A. Bose, C.H. Saha, J. Mol. Catal. 49 (1989) 271.
[9] M. López-Torres, A. Fernández, J.J. Fernández, S. Castro-Juiz, A. Suárez,
J.M. Vila, M.T. Pereira, Organometallics 20 (2001) 1350.
[10] A. Gómez-Quiroga, C. Navarro-Ranninger, Coord. Chem. Rev. 248 (2004) 119.
[11] I. Omae, J. Organomet. Chem. 692 (2007) 2608.
N) 1605s,
J Hz):
y d ppm,
(PdeCl) 279 cmꢀ1. RMN 1H (300 MHz, CDCl3,
d
¼ 7.07 [1H, d, 3J3,4 7.7, H4], 6.99 [1H, s, H6], 6.73 [1H, br, H9],
6.53 [1H, d, H3], 2,81 [2H, br, CH2], 2.37, 2.32, 1.98 [12H, s, Me]. 31P-
{1H} NMR (211.49 MHz, CDCl3,
d ppm): 46.30 (s). MS-FAB: m/
z
L
¼
1168 [(L-H)2Pd2(vdpp)(Cl)]þ. Specific molar conductivity,
¼ 136.6 Uꢀ1 cm2 molꢀ1 (in acetonitrile).
m
4.2.13. [{Pd[1-CH2-2-{HC]N(2,4,6-Me3C6H2)}-4-MeC6H3-
C,N]}2( -Ph2PCH2PPh2)(
m
m
-Br)][Br] 7a0
Compound 7a0 was obtained as a pale yellow solid, following
a similar procedure to the one used in the synthesis of 6a0 but using
2a0 as starting material.
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requires C, 58.2; H, 5.0; N, 2.2%. IR:
283 cmꢀ1. RMN 1H (300 MHz, CDCl3,
H6], 6.93 [1H, d, J3,4 7.8, H4], 6.84 [1H, br, H9], 6.20 [1H, d, H3], 2.69
n
(C]N) 1610s,
y(PdeCl)
d
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