Rigid-rod structured palladium complexes

Article abstract of DOI:10.1016/j.ica.2005.08.033

Mononuclear and homobimetallic palladium complexes of structural type [trans-(Me(O)CS-4-C₆H₄)(Ph₃P) ₂Pd(N^∩N)]OTf (8a, N^∩NC ₄H₄N₂; 8b, N^∩NC ₅

Full text of DOI:10.1016/j.ica.2005.08.033

Inorganica Chimica Acta 359 (2006) 1899–1906
www.elsevier.com/locate/ica
Rigid-rod structured palladium complexes
*
Deeb Taher, Bernhard Walfort, Heinrich Lang
Technische Universita¨t Chemnitz, Fakulta¨t fu¨r Naturwissenschaften, Institut fu¨r Chemie, Lehrstuhl fu¨r Anorganische Chemie,
Straße der Nationen 62, D-09111 Chemnitz, Germany
Received 4 August 2005; accepted 16 August 2005
Available online 23 November 2005
Dedicated to Professor Gerard van Koten.
Abstract
Mononuclear and homobimetallic palladium complexes of structural type [trans-(Me(O)CS-4-C6H4)(Ph3P)2Pd(N\N)]OTf (8a,
N\N@C4H4N2; 8b, N\N@C5H4N-4-C„N) and {[trans-(Me(O)CS-4-C6H4)(Ph3P)2Pd]2N\N}(OTf)2 (9a, N\N = 4,40-bipyridine
(=bipy); 9b, N\N = C6H4-1,4-(C„N)2; 9c, N\N = (C6H4-4-C„N)2) are accessible by the reaction of trans-(Ph3P)2Pd(C6H4-4-SC(O)-
Me)(OTf) (6) with 1 or 0.5 equivalents of the Lewis-bases N\N (7a, N\N = C4H4N2; 7b, N\N = C5H4N-4-C„N; 7c, N\N = bipy;
7d, N\N = C6H4-1,4-(C„N)2; 7e, N\N = (C6H4-4-C„N)2) in high yield. Complex 6 can be prepared in a two-step synthesis procedure.
Oxidative addition of I-1-C6H4-4-SC(O)Me (2) to Pd(PPh3)4 (3) gives trans-(Ph3P)2Pd(C6H4-4-SC(O)Me)(I) (4), which further reacts
with [AgOTf] (5) to afford 6.
The formation of 8 and 9 strongly depends on the size of the Lewis-bases N\N. It is obvious that the co-ordination of the second
N-ligated site of 8a or 8b to a further bulky [(PPh3)2Pd(C6H4-4-SC(O)Me)]+ unit is not possible. In contrast, more extended N\N species
such as 7c–7e will result in the formation of linear structured homobimetallic 9a–9c.
The solid-state structures of 4 and 4 Æ CH2Cl2 are reported. Complex 4 is packed in the orthorhombic space group Pbca. The assembly
ꢀ
of dichloromethane into the crystal lattice breaks the symmetry, whereby 4 Æ CH2Cl2 crystallises in the triclinic space group P1. In both
modifications a square-planar palladium(II) ion is present, with the iodo atom and the Me(O)CS-C6H4 unit trans-positioned. The
different crystal packing has no significant influence onto the geometry around the d8-configurated palladium atoms.
ꢀ 2005 Elsevier B.V. All rights reserved.
Keywords: Palladium; Nitrogen Lewis-bases; Oxidative addition; Homobimetallic; Molecular wire; X-ray structure
1. Introduction
assembly processes onto metal surfaces of gold or silver
[24]. In contrast to ultra-thin films made by, i.e., molecular
beam epitaxy or chemical vapour deposition, self-assem-
bled monolayers (SAMs) are highly ordered and orientated
and can incorporate a wide range of diverse groups into as
well as at the end of the chain [25]. This means that by
chemical control a variety of functionalised surfaces with
specific interactions can be produced.
With the advancement in nanoscale molecular electronic
devices, organic and organometallic functionalised thiols
have recently received great attention [1–10]. This is attrib-
uted to their intrinsic or insulator properties [11–21].
Among them, conjugated thiol end-capped molecules, such
as 1,4-ethynyl-phenylene and bis-9,10-phenyl-ethynylan-
thracene have been widely studied as molecular wires
[22,23]. In addition, such molecules can be used in molecu-
lar electronics to form well-ordered monolayers by self-
One-dimensional dithiols are also very unique in their
use as molecular wires to span two metal surfaces allowing
through-bridge exchange of electrons [26].
Next to organic, for example, biphenyl- and fluorenyl-
based end-capped dithiols, also very recently thiol
end-grafted organometallic compounds, i.e., trans-(Ph3P)2-
Pt(C„C–C6H4-4-SC(O)Me)2 became available [27]. As it
*
Corresponding author. Tel.: +49 371 531 1200; fax: +49 371 531 1833.
E-mail address: heinrich.lang@chemie.tu-chemnitz.de (H. Lang).
0020-1693/$ - see front matter ꢀ 2005 Elsevier B.V. All rights reserved.
doi:10.1016/j.ica.2005.08.033

1900
D. Taher et al. / Inorganica Chimica Acta 359 (2006) 1899–1906
could be shown by Mayor et al. [27] such complexes act as a
single-molecular insulator. More recently, we became inter-
ested in this field of study [28].
We describe here the synthesis and properties of mono-
and homo-bimetallic acetyl-S end-capped palladium
complexes.
Surprisingly, iodide abstraction from 4 by using [AgBF4]
resulted in the decomposition of 4. However, when
[AgOTf] (5) (TfO = triflate, OSO2CF3) is reacted with 4
in toluene–dichloromethane mixtures of ratio 5:2 the
in situ formation of trans-(Ph3P)2Pd(C6H4-4-SC(O)Me)
(OTf) (6) is observed (Scheme 1). Addition of the Lewis-
bases N\N (7a, N\N = C4H4N2; 7b, N\N = C5H4N-4-
C„N; 7c, N\N = bipy; 7d, N\N = C6H4-1,4-(C„N)2;
7e, N\N = (C6H4-4-C„N)2) to 6 in a 1:2 stoichiometry
gives either the mono-nuclear palladium complexes 8a
and 8b, or the respective homobimetallic rigid-rod struc-
tured molecules 9a–9c (Scheme 1, Table 1). This result
was at first astonishing, because we expected the only for-
mation of linear homobimetallic species. Complexes 8a and
8b can be synthesised in a more straightforward way by
using a 1:1 molar ratio of 6 and 7 (Scheme 1).
2. Results and discussion
For the preparation of [trans-(Me(O)CS-4-C6H4)-
(Ph3P)2Pd(N\N)]OTf (8a, N\N = C4H4N2; 8b, N\N =
C5H4N-4-C„N) and {[trans-(Me(O)CS-4-C6H4)(Ph3P)2-
Pd]2N\N}(OTf)2 (9a, N\N = 4,40-bipyridine (=bipy); 9b,
N\N = C6H4-1,4-(C„N)2; 9c, N\N = (C6H4-4-C„N)2)
we decided to use trans-(Ph3P)2Pd(C6H4-4-SC(O)Me)(I)
(4) as precursor complex, which can be synthesised by the
oxidative addition of 1-I-C6H4-4-SC(O)Me (2) to Pd(PPh3)4
(3). However, it appeared that the synthesis of thiol 2 was
the critical step in the synthesis protocol of 4, since this mol-
ecule is only available in a low yield reaction [29]. Out of this
reason we had to develop an improved synthetic procedure
to obtain 2 in much higher yield. This problem could be
solved by using stronger aprotic solvents. Subsequent treat-
ment of C6H4-1,4-(I)2 (1) with tBuLi, 1/8 S8 and MeC(O)Cl
in tetrahydrofuran at low temperature affords thiol 2 as a
colourless solid in yields up to 85% (Eq. (1)). Further reac-
tion of 2 with stoichiometric amounts of Pd(PPh3)4 (3)
produces by loss of two Ph3P ligands mononuclear trans-
(Ph3P)2Pd(C6H4-4-SC(O)Me)(I) (4) (Eq. (1)). After appro-
priate work-up, complex 4 can be isolated as a yellow solid
in excellent yield (Section 4).
Table 1
Synthesis of complexes 8 and 9
Compound
Yielda (%)
75
N
N
N
8a
N
8b
9a
75
86
N
C
N
N
N
O
1. t-BuLi
2. 1/8 S8
Me
I
I
S
I
3. MeC(O)Cl
9b
80
87
N
C
C
N
1
2
ð1Þ
O
PPh
Pd
3
9c
Pd(PPh3)4 (3)
S
I
Me
N
N
C
C
- 2 PPh3
PPh
3
4
a
Based on 4.
+
O
-
OTf
PPh
3
3
Me
S
Pd
N
N
PPh
O
O
8a, 8b
PPh
PPh
Pd
3
3
[AgOTf] (5)
N
N
(7)
Me
S
Pd OTf
S
I
Me
- AgI
PPh
3
PPh
3
4
6
2+
2 OTf
-
O
O
PPh
Pd
PPh
3
3
3
Me
Me
S
N
N
Pd
PPh
S
PPh
3
9a-9c
Scheme 1. Synthesis of mononuclear 8a and 8b, and homobimetallic 9a–9c (Table 1).

D. Taher et al. / Inorganica Chimica Acta 359 (2006) 1899–1906
1901
Complexes 8 and 9 can be precipitated as yellow solids
from the reaction medium by slow addition of n-hexane.
Due to their ionic nature, they only dissolve in polar
organic solvents including tetrahydrofuran, dichlorometh-
ane and chloroform. However, in acetonitrile, dimethylsul-
fide and dimethylformamide they decompose even at low
temperature. They also decompose on exposure to air
and moisture. Under inert gas atmosphere 8 and 9 can be
stored for months at ꢀ30 ꢁC.
Compounds 4, 8 and 9 were fully characterised by ele-
mental analysis, IR and NMR (1H, 31P{1H}) spectroscopy.
Additionally, from 4 and 4 Æ CH2Cl2 the solid-state struc-
tures could be determined.
In the IR spectra of 8 and 9 the triflate counter ion gives
rise to one very characteristic mSO-absorption at ca.
1265 cmꢀ1 which is consistent with the non-coordinating
character of the triflate group [30]. For the acetyl moiety a
distinct CO stretching vibration is found at ca. 1700 cmꢀ1
which appears at the same wave-number as 2 (Section 4).
The mC„N absorption of the cyano group(s) in 8b, 9b and
9c is observed at 2280, 2275 and 2260 cmꢀ1. These bands
are shifted to higher wave-numbers, when compared to 7b
(2244 cmꢀ1), 7d (2234 cmꢀ1) or 7e (2228 cmꢀ1) [30]. This
clearly indicates the coordination of the cyano units to the
palladium(II) centres in 8b, 9b and 9c, respectively. This
finding resembles to data found for other transition metal
complexes, i.e., {[(dppp)Pd][C6H4-1,4-(C„N)2]2(OTf)2}4
(2280 cmꢀ1) [30].
Fig. 1. XP-plot (50% probability level) of complex 4 with the atom-
numbering scheme.
mental data for the X-ray diffraction studies are given in
Table 3 (Section 4).
The palladium(II) ion in both modifications possesses a
square-planar environment, caused by the two trans-posi-
tioned Ph3P groups (P1, P2), the r-bound iodide I1 and
1
˚
the Me(O)CS-4-C6H4 group (Fig. 1) (4: r.m.s.d. 0.0919 A,
The H NMR spectra of 4, 8 and 9 show well-resolved
˚
4 Æ CH2Cl2: 0.0773 A). The latter building block is perpen-
resonance signals for the corresponding organic groups
Me(O)CS, C6H4, C6H5, C5H4N, C4H4N2 and bipy with
the expected coupling pattern. The spectra further show
the formation of mono- (8) or dinuclear molecules (9),
which can be concluded from the signal intensities of the
latter units.
dicular orientated to the transition metal co-ordination
plane (93.2ꢁ (4) and 89.9ꢁ (4 Æ CH2Cl2)). The Pd–I, Pd–P
and Pd–C separations (Table 2) are in the typical range
as reported for similar species [32]. Complex 4 is packed
in the orthorhombic space group Pbca. The assembly of
dichloromethane into the crystal lattice breaks the symme-
try, whereby 4 Æ CH2Cl2 crystallises in the triclinic space
However, it was not possible to obtain 13C{1H} NMR
spectra of all palladium complexes, since it appeared that
some of these species are less soluble in common organic
solvents (vide supra and Section 4).
ꢀ
group P1. Complex 4 is build-up by the formation of tubes
along the crystallographic axes a of equal oriented species
of 4. These tubes are forming along the crystallographic
axes b four different layers with the iodo atom positioned
up and down, to the left and to the right, and are staggered
into each other by the PPh3 phenyl groups (Fig. 2, left).
In 4 Æ CH2Cl2 equal orientated tubes are formed by 4
with an alternate up and down orientation of the iodo
atoms. These tubes are forming a layer along the crystallo-
graphic axes a. Between these layers the dichloromethane
solvent molecules are assembled into the crystal lattice
(Fig. 2, right). The different crystal packing in 4 and
4 Æ CH2Cl2 has no significant influence onto the geometries
around palladium.
Characteristic for the 31P{1H} NMR spectra of 8 and 9
is the appearance of one sharp signal at ca. 21 ppm, which
can be assigned to the Ph3P units. Compared with free
Ph3P [31] the signals in 8 and 9 are shifted to lower field.
When one compares the 31P{1H} NMR chemical shift of
4 (22 ppm) with that ones typical for 8 and 9 a high-field
shift by ca. 1 ppm is characteristic. This allows to monitor
the reaction of 4 with 5 and 7 to give 8 and 9, respectively.
Single crystals suitable for X-ray structure determina-
tion could be obtained by diffusion of n-hexane into a
dichloromethane solution containing 4 at ꢀ30 ꢁC, whereby
two different type of crystals were formed. One sort is sol-
vent free (4), while in the second crop of crystals one
dichloromethane molecule is assembled into the crystal lat-
tice (4 Æ CH2Cl2). The molecular structure of 4 is depicted in
Fig. 1, while the different crystal packing of 4 and
4 Æ CH2Cl2 is shown in Fig. 2. Selected geometrical details
for 4 and 4 Æ CH2Cl2 are listed in Table 2, and the experi-
3. Conclusion
A straightforward synthesis method for the preparation
of thiol end-capped mono- and homo-bimetallic palladium
complexes is reported. The key steps are the oxidative

1902
D. Taher et al. / Inorganica Chimica Acta 359 (2006) 1899–1906
Fig. 2. Crystal lattices of 4 (left) and 4 Æ CH2Cl2 (right).
Table 2
Table 3
a
˚
Selected bond distances (A) and angles (ꢁ) for 4 and 4 Æ CH2Cl2
Crystal data and structure refinement for 4 and 4 Æ CH2Cl2
4
4 Æ CH2Cl2
Compound
4
4 Æ CH2Cl2
Pd(1)–C(37)
C(40)–S(1)
Pd(1)–P(2)
Pd(1)–I(1)
Pd(1)–P(1)
S(1)–C(43)
2.007(7)
1.780(9)
2.3546(2)
2.7021(9)
2.342(2)
1.747(17)
2.008(5)
1.765(5)
2.3286(12)
2.6874(5)
2.3411(12)
1.68(3)
Empirical formula
M
C44H37IOP2PdS
909.04
Pbca
C45H39Cl2IOP2PdS
993.96
ꢀ
Space group
P1
˚
a (A)
10.4205(12)
23.294(3)
32.716(4)
90
90
90
7941.1(16), 8
1.521
1.411
1.24–26.43
69477/8980/0.1302
13.3448(8)
13.7490(8)
14.0713(8)
70.919(1)
62.358(1)
77.858(1)
2156.1(2), 2
1.531
1.426
1.73–28.48
25011/10393/0.0557
˚
b (A)
˚
c (A)
a (ꢁ)
b (ꢁ)
c (ꢁ)
P(1)–Pd(1)–C(37)
P(2)–Pd(1)–C(37)
P(2)–Pd(1)–P(1)
C(37)–Pd(1)–I(1)
P(1)–Pd(1)–I(1)
P(2)–Pd(1)–I(1)
a
87.2(2)
87.3(2)
174.02(7)
168.3(2)
91.40(5)
93.61(5)
88.45(12)
87.48(12)
172.38(5)
176.50(13)
94.06(3)
3
˚
V (A ), Z
Dc (Mg mꢀ3
l (mmꢀ1
h Range (ꢁ)
)
)
90.29(3)
The estimated standard deviations of the last significant digits are
shown in parentheses.
Reflections collected/
unique/Rint
Data/restraints/parameter
8131/0/452
0.0717
0.2060
10393/130/537
0.0521
0.1438
a
R1 [I > 2r(I)]
b
addition of 1-I-C6H4-4-SC(O)Me to Pd(PPh3)4 and the
conversion of trans-(Ph3P)2Pd(Me(O)CS-4-C6H4)(I) with
[AgOTf] to [trans-(Ph3P)2Pd(Me(O)CS-4-C6H4)](OTf).
The latter molecule allows the synthesis of mono- and
homo-bimetallic palladium complexes featuring thiol
end-capped phenylene units, whereby the palladium cen-
tres are spanned by carbon-rich nitrogen-containing bridg-
ing units. The control over these reaction is given by the
different size of the Lewis-bases N\N and resembles to
the bulkiness of the organometallic entity [(Me(O)CS-4-
C6H4)(Ph3P)2Pd]+. The newly synthesised complexes are
rigid-rod structured. Their use for the application of
self-assembled monolayers and/or to span two metal sur-
faces to allow through-bridge exchange of electrons (or
act as single-molecular insulator) is subjected to further
studies.
wR2 (all data)
Largest difference in peak
1.161, ꢀ1.725
1.062, ꢀ1.252
ꢀ3
˚
and hole (e A
P
)
kF oj ꢀ jF ck
a
b
P
R1 ¼
.
jF oj
sffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi
P
2
wðF 2o ꢀ F 2c Þ
1
wR2 ¼
with w ¼
;
P
2
2
wðF 2oÞ
r2ðF 2oÞ þ ðg1PÞ þ g2P
ðmaxðF 2o; 0Þ þ 2F 2c Þ
P ¼
.
3
4. Experimental
4.1. General methods
All reactions were carried out in an atmosphere of
purified nitrogen (O2 traces: CuO catalyst, BASF AG,

D. Taher et al. / Inorganica Chimica Acta 359 (2006) 1899–1906
1903
C6H4). 13C{1H} NMR (CDCl3): d = 30.3 (CH3), 96.0 (C–
I/C6H4), 127.7 (CH/C6H4), 135.88 (CH/C6H4), 138.5 (iC/
C6H4), 194.0 (CO).
˚
Ludwigshafen, Germany; H2O traces: molecular sieve, 4 A,
Roth company) using standard Schlenk techniques. Sol-
vents were purified by distillation (n-hexane and dichloro-
methane:
calcium
hydride;
toluene,
sodium;
tetrahydrofuran: sodium/benzophenone ketyl). FT-IR
spectra were recorded with a Perkin–Elmer FT-IR 1000
spectrometer (KBr). NMR spectra were recorded with a
Bruker Advance 250 spectrometer, operating in the Fourier
transform mode. 1H NMR spectra were recorded at
250.123 MHz (internal standard, relative to CDCl3, d
7.26). 13C{1H} NMR spectra were recorded at
67.890 MHz (internal standard, relative to CDCl3, d
77.16). Chemical shifts are reported in d units (ppm) down-
field from tetramethylsilane (d 0.00) with the solvent signal
as reference. 31P{1H} NMR were recorded at 101.202 MHz
in CDCl3 with P(OMe)3 as external standard (d 139.0, rel-
ative to 85% H3PO4, d 0.00). Melting points were deter-
mined using analytically pure samples, sealed off in
nitrogen-purged capillaries with a Gallenkamp MFB 595
010 melting point apparatus. Microanalyses were per-
formed by the Organic Department at Chemnitz the Uni-
versity of Technology and the Institute of Organic
Chemistry at the University of Heidelberg.
4.4. Synthesis of 4
Molecule 2 (0.1 g, 0.36 mmol) is dissolved in 30 mL of
toluene and one equivalent of Pd(Ph3)4 (3) (0.412 g,
0.36 mmol) is added in one portion at 25 ꢁC. During 24 h
of stirring at this temperature a yellow precipitate forms.
All volatiles are removed in oil-pump vacuum and the res-
idue is dissolved in dichloromethane (5 mL). n-Hexane
(60 mL) is added, whereby a yellow solid precipitates.
The supernatant layer is decanted and the residue is washed
twice with n-hexane (20 mL) to give 4 as a yellow solid.
Yield: 0.32 g (0.25 mmol, 70% based on 2).
M.p.: 150 ꢁC (dec.). Anal. Calc. for C44H37IOP2PdS
(909.10): C, 58.13; H, 4.10; S, 3.53. Found: C, 58.42; H,
4.35; S, 3.41%. IR (KBr): 2962 (m), 1705 (s) (mCO), 1636
(s), 1478 (s), 1432 (vs), 1400 (vs), 1261 (s), 1092 (sh), 1025
(s), 796 (s), 744 (s), 692 (vs), 612 (m), 517 (vs) cmꢀ1. H
1
NMR (CDCl3): d = 2.2 (s, 3H, CH3), 6.2 (d, 2H,
JHH = 8.2 Hz, C6H4), 6.6 (dt, 2H, JHH = 8.2 Hz,
4JHP = 3.9 Hz, C6H4), 7.2–7.6 (m, 30H, PPh3). 31P{1H}
NMR (CDCl3): d = 21.7. 13C{1H} NMR (CDCl3):
d = 30.1 (CH3), 127.6 (iC/C6H4), 127.8, 127.9, 128.0
(C6H4), 129.9 (iC/C6H4), 131.4, 132.2, 133.1, 134.5, 134.8,
134.9, 135.0, 135.2, 136.6 (C6H5), 178.5 (CO).
4.2. General remarks
Chemicals were purchased from commercial suppliers
and were used as received. For 8a and 8b no 13C{1H}
NMR data could be obtained, since these species are only
less soluble in common organic solvents.
4.5. Synthesis of 8a
4.3. Modified synthesis of 2 [29,33]
[AgOTf] (5) (48.0 mg, 0.187 mmol) is added in one por-
tion to 4 (170.7 mg, 0.187 mmol), which is dissolved in a tol-
uene-dichloromethane mixture of ratio 5:2 (50 mL) at
25 ꢁC. After 30 min of stirring, the reaction mixture is fil-
tered through a pad of Celite. To this solution pyrazine
(7a) (1.5 mg, 0.187 mmol) is added and the resulting suspen-
sion is stirred for additional 30 min. On addition of 50 mL
of n-hexane a yellow precipitate forms. The supernatant
solution is removed by filtration with a canula and the resi-
due is dried in oil-pump vacuum. Complex 8a is obtained as
a yellow solid. Yield: 136 mg (0.133 mmol, 75% based on 4).
M.p.: 78 ꢁC (dec.). Anal. Calc. for C48H41F3N2O4P2Pd-
S4 Æ 0.5CH2Cl2 (1061.84): C, 56.42; H, 4.02; N, 2.66.
Found: C, 56.21; H, 4.14; N, 2.38%. IR (KBr): 3053 (m),
2924 (m), 1701 (s) (mCO), 1654 (m), 1479 (m), 1434 (s),
1416 (sh), 1260 (vs) (ms(SO)), 1223 (m), 1153 (s), 1094 (s),
1051 (m), 1028 (s) (mCF), 1009 (m), 811 (s), 745 (s), 693
1,4-Diiodobenzene (1) (5.00 g, 15.20 mmol) is dissolved
in tetrahydrofuran (300 mL) and tBuLi (17.88 mL,
30.40 mmol, 1.7 M in n-pentane) is drop-wise added at
ꢀ78 ꢁC during 10 min. After stirring the reaction mixture
for another 10 min at this temperature, sulfur (0.48 g,
15.20 mmol) dissolved in tetrahydrofuran (75 mL) is added
drop-wise at 0 ꢁC, and the reaction mixture is allowed to
warm to 0 ꢁC and stirred for additional 45 min at this tem-
perature. Afterwards, the reaction mixture is again cooled
to ꢀ78 ꢁC and acetyl chloride (1.19 g, 15.20 mmol) is added
in one portion. The thus obtained reaction solution is
allowed to warm to room temperature overnight. Water
(20 mL) is added and extraction with dichloromethane
(3 · 50 mL) is carried out. The combined layers are dried
over magnesium sulfate. The solvent is removed by rotary
evaporation and the residue is purified by chromatography
(Silica gel, column size 20 · 2.5 cm; n-hexane/dichloro-
methane, ratio 10:3). The solvents are removed from the
eluate in oil-pump vacuum to leave a colourless solid.
Yield: 3.5 g (12.77 mmmol, 84% based on 1).
1
(s), 636 (s), 518 (vs) cmꢀ1. H NMR (CDCl3): d = 2.3 (s,
3H, CH3), 6.5 (d, 2H, JHH = 7.4 Hz, C6H4), 6.9 (m, 8H,
C6H4), 7.2–7.3 (m, 30H, PPh3), 8.2 (m, 2H, C4H4N2), 8.6
(m, 2H, C4H4N2). 31P{1H} NMR (CDCl3): d = 19.1.
M.p.: 54 ꢁC. IR (KBr): 3082 (m), 1904 (w), 1698 (vs)
(mCO), 1470 (s), 1378 (m), 1121 (s), 1092 (s), 999 (s), 808
4.6. Synthesis of 8b
1
(vs) cmꢀ1. H NMR (CDCl3): d = 2.4 (s, 3H, CH3), 7.1
To 4 (164.7 mg, 0.184 mmol) dissolved in 30 mL of a tol-
(d, 2H, JHH = 8.2 Hz, C6H4), 7.7 (d, 2H, JHH = 8.2 Hz,
uene–dichloromethane mixture of ratio 5:2 one equivalent

1904
D. Taher et al. / Inorganica Chimica Acta 359 (2006) 1899–1906
of [AgOTf] (5) (47 mg, 0.184 mmol) is added in one portion
at 25 ꢁC. After 30 min of stirring, the reaction mixture is fil-
tered through a pad of Celite. To the eluate iso-nicotinonit-
rile (7b) (19 mg, 0.092 mmol) is added in one portion at
25 ꢁC and the resulting suspension is stirred for 30 min.
After appropriate work-up (see synthesis of 8a), complex
8b can be isolated as a yellow solid. Yield: 155 mg
(0.15 mmol, 75% based on 4).
stirring, the reaction mixture is filtered through a pad of
Celite. Terephthalonitrile (7d) (15.6 mg, 0.122 mmol) is
added to the eluate and the resulting suspension is stirred
for 30 min. Addition of 80 mL of n-hexane affords a color-
less precipitate. The solvents are removed by filtration and
the residue is dried in oil-pump vacuum. Complex 9b is
obtained as a yellow solid (194 mg, 0.098 mmol, 80% based
on 4).
M.p.: 60 ꢁC (dec.). Anal. Calc. for C51H41F3N2O4-
P2PdS2 (1035.37): C, 59.16; H, 3.99; N, 2.71. Found: C,
59.17; H, 4.01; N, 2.44%. IR (KBr): 3054 (s), 2280 (w)
(mC„N), 1703 (s) (mCO), 1609 (m), 1551 (w), 1480 (m),
1435 (s), 1416 (sh), 1260 (vs) (ms(SO)), 1223 (sh), 1153 (s),
1118 (w), 1095 (s), 1051 (m), 1029 (vs) (mCF), 1009 (m),
944 (m), 812 (s), 746 (s), 693 (vs), 637 (vs), 570 (w), 519
M.p.: 125 ꢁC (dec.). Anal. Calc. for C98H78F6N2O8P4-
Pd2S4 (1990.66): C, 59.13; H, 3.95; N, 1.41. Found: C,
59.45; H, 4.02; N, 1.43%. IR (KBr): 3052 (m), 2275 (m)
(mC„N), 1700 (s) (mCO), 1553 (m), 1480 (s), 1466 (s), 1435
(s), 1402 (s), 1266 (vs) (ms(SO)), 1223 (sh), 1187 (w), 1151
(s), 1094 (s), 1051 (m), 1030 (vs) (mCF), 1009 (sh), 998
(m), 943 (w), 849 (w), 807 (s), 751 (s), 693 (vs), 636 (vs),
1
1
(vs) cmꢀ1. H NMR (CDCl3): d = 2.3 (s, 3H, CH3), 6.5
568 (m), 520 (s), 508 (s) cmꢀ1. H NMR (CDCl3): d = 2.4
(d, 2H, JHH = 7.7 Hz, C6H4), 6.9 (d, 2H, JHH = 7.7 Hz,
C6H4), 7.2–7.3 (m, 30H, PPh3), 8.0 (bs, 2H, C5H4NCN),
8.2 (bs, 2H/C5H4NCN). 31P{1H} NMR (CDCl3): d = 19.1.
(s, 6H, CH3), 6.5 (d, 4H, JHH = 8.0 Hz, C6H4), 6.6 (d,
4H, JHH = 8.0 Hz, C6H4), 7.0 (s, 4H, NCC6H4NC), 7.3–
7.4 (m, 60H, PPh3). 31P{1H} NMR (CDCl3): d = 20.5.
13C{1H} NMR (CDCl3): d = 30.2 (CH3), 118.2 (iC/
C6H4), 122.3, 125.3, 127.6, 127.9, 128.2 (C6H5), 128.4,
129.0 (C6H4/C6H5), 129.1 (iC/C6H4CN), 129.3 (C6H4),
130.6 (iC/C6H4CN), 131.4 (iC/C6H4), 133.4 (C6H4CN),
133.8, 133.9 (C6H5), 134.0 (C6H4CN), 134.2, 135.9
(C6H5), 194.0 (CO).
4.7. Synthesis of 9a
trans-(PPh3)2Pd(C6H4-4-SC(O)CH3)(I) (4) (201 mg,
0.22 mmol) is dissolved in a mixture of toluene-dichloro-
methane (ratio 5:2) (50 mL) and then one equivalent of
[AgOTf] (5) (56 mg, 0.22 mmol) is added at 25 ꢁC. After
stirring the reaction mixture for 30 min, it is filtered
through a pad of Celite. To the thus obtained eluate,
4,40-bipyridine (7c) (17 mg, 0.11 mmol) is added at 25 ꢁC
and the resulting suspension is stirred for 30 min. On
addition of 80 mL of n-hexane a yellow precipitate is
formed. The supernatant solution is decanted and the res-
idue is dried in oil-pump vacuum. Complex 9a is obtained
as a yellow solid. Yield: 192 mg (0.095 mmol, 86% based
on 4).
4.9. Synthesis of 9c
[AgOTf] (5) (56 mg, 0.22 mmol) is added in one portion
to 4 (199.2 mg, 0.22 mmol) in a mixture of toluene–dichlo-
romethane (ratio 5:2) (40 mL) at 25 ꢁC. After 30 min of
stirring, the reaction mixture is filtered through a pad
of Celite. 4,40-Biphenyldicarbonitrile (7e) (22.3 mg,
0.11 mmol) is added in one portion to the eluate. After
30 min of stirring, 50 mL of n-hexane are added, whereby
a colourless precipitate is formed. The solvents are
removed by filtration and the residue is dried in oil-pump
vacuum. Complex 9c is obtained as a colourless solid
(197 mg, 0.095 mmol, 87% based on 4).
M.p.: 142 ꢁC (dec.). Anal. Calc. for C100H82F6N2O8P4-
Pd2S4 (2018.72): C, 59.50; H, 4.09; N, 1.39. Found: C,
59.45; H, 4.02; N, 1.43%. IR (KBr): 3054 (m), 2964 (w),
1702 (s) (mCO), 1636 (s), 1609 (s), 1481 (m), 1435 (s), 1401
(sh), 1265 (vs) (ms(SO)), 1223 (sh), 1154 (s), 1096 (m), 1030
(s) (mCF), 1008 (s), 959 (w), 806 (s), 749 (s), 694 (s), 637
M.p.: 132 ꢁC (dec.). Anal. Calc. for
C104H82F6N2O8-
P4Pd2S4 (2066.76): C, 60.44; H, 4.00; N, 1.36. Found: C,
59.99; H, 4.02; N, 1.55%. IR (KBr): 2933 (m), 2260 (m)
(mC„N), 1702 (s) (mCO), 1553 (m), 1480 (s), 1468 (sh), 1435
(s), 1398 (w), 1264 (vs) (ms(SO)), 1222 (sh), 1151 (s), 1118
(m), 1095 (s), 1030 (vs) (mCF), 1007 (sh), 947 (w), 825 (m),
804 (s), 747 (s), 693 (vs), 637 (vs), 572 (m), 520 (s), 508
1
(s), 573 (w), 521 (s) cmꢀ1. H NMR (CDCl3): d = 2.2 (s,
6H, CH3), 6.5 (d, 4H, JHH = 8.0 Hz, C6H4), 6.9 (d, 4H,
JHH = 8.0 Hz, C6H4), 7.0 (d, 4H, JHH = 6.3 Hz, bipy),
7.2–7.3 (m, 60H, PPh3), 8.1 (d, 4H, JHH = 6.3 Hz, bipy).
31P{1H} NMR (CDCl3): d = 19.6. 13C{1H} NMR
(CDCl3): d = 30.0 (CH3), 118.6 (iC/C6H4), 122.4, 123.2
(C6H5), 123.7 (iC/C6H4), 125.2, 127.4, 127.8, 128.2, 128.9,
129.0, 129.1 (C6H4/C6H5), 130.8 (iC/bipy), 133.7, 133.8,
133.9, 137.3, 137.8, 144.3 (C6H5), 148.7 (bipy), 151.9
(bipy), 194.1 (CO).
(s) cmꢀ1 1H NMR (CDCl3): d = 2.4 (s, 6H, CH3), 6.5
.
(d, 4H, JHH = 7.9 Hz, C6H4), 6.6 (d, 4H, JHH = 8.1 Hz,
C6H4CN), 6.7 (d, 4H, JHH = 7.9 Hz, C6H4), 7.3–7.4 (m,
60H, PPh3), 7.7 (d, 4H, JHH = 8.1 Hz, C6H4CN).
31P{1H} NMR (CDCl3): d = 20.9. 13C{1H} NMR
(CDCl3): d = 30.0 (CH3), 118.8 (iC/C6H4), 122.9
(C6H4CN), 125.3, 127.7, 128.1 (C6H4/C6H5), 128.2 (iC/
C6H4CN), 128.5 (C6H5), 129.1 (iC/C6H4), 129.2 (C6H5),
129.3 (C6H4CN), 130.6 (iC/C6H4CN), 131.6 (C6H5), 133.2
(C6H4), 133.7, 133.8, 133.9, 134.2 (C6H5), 135.9
(C6H4CN), 193.9 (CO).
4.8. Synthesis of 9b
[AgOTf] (5) (62.6 mg, 0.244 mmol) is added to 4
(226.6 mg, 0.244 mmol) in a mixture of toluene and dichlo-
romethane (ratio 5:2) (60 mL) at 25 ꢁC. After 30 min of

D. Taher et al. / Inorganica Chimica Acta 359 (2006) 1899–1906
1905
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5. X-ray structure determination
For data collection of 4 and 4 Æ CH2Cl2 a Bruker Smart
1K CCD diffractometer with graphite monochromatised
˚
Mo Ka radiation (k = 0.71073 A) was used. For protection
against oxygen and moisture, the preparation of single
crystals was preformed in perfluoro alkyl ether (ABCR
GmbH&Co KG; viscosity 1600 cSt). Data collection and
cell determination has been done with the program SMART
[34,35]. For data integration and refinement of the unit cell
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The structure of 4 was solved by direct methods with the
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both domains are separated with the program RLATT [38].
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[34,35] integration of the data is performed with fixed
matrices and fixed box sizes. With the program GEMINI
new raw file of the reflections of the first domain is written
without reflections overlapping stronger than 0.015 A. The
structure was solved by Patterson methods using SHELXS-97
[37].
4
a
˚
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In 4 Æ CH2Cl2 the dichloromethane and the thioacetate
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5. Supplementary material
The crystallographic data for 4 and 4 Æ CH2Cl2 have
been deposited with the Cambridge Crystallographic Data
Centre as supplementary publication no. CCDC 280925 (4)
and CCDC 280926 (4 Æ CH2Cl2). Copies of this information
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