Synthesis, structure, and quaternization and complexation reactions of κ3SCS pincer palladium complexes having 3,5-pyridinediyl unit

Article abstract of DOI:10.1016/j.jorganchem.2007.12.033

The cyclopalladation of 3,5-bis(diphenylphosphinothioyl)pyridine afforded new κ³S,C,S-pincer palladium complexes with a σ-bond between Pd and 4C of the centered 3,5-pyridinediyl unit. By utilizing the quaternization and complexation ability of the pyridine imine nitrogen (N_py) atom, various new pincer-type complexes, including hetero-binuclear complexes, have been synthesized.

Full text of DOI:10.1016/j.jorganchem.2007.12.033

Available online at www.sciencedirect.com
Journal of Organometallic Chemistry 693 (2008) 1109–1116
www.elsevier.com/locate/jorganchem
Synthesis, structure, and quaternization and complexation reactions
of j3SCS pincer palladium complexes having 3,5-pyridinediyl unit
Hikaru Meguro a, Take-aki Koizumi a, Takakazu Yamamoto a, Takaki Kanbara b,c,
*
a Chemical Resources Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan
b Tsukuba Research Center for Interdisciplinary Materials Science (TIMS), University of Tsukuba, 1-1-1 Tennoudai, Tsukuba 305-8573, Japan
c Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba 305-8573, Japan
Received 29 October 2007; received in revised form 27 December 2007; accepted 28 December 2007
Available online 8 January 2008
Abstract
The cyclopalladation of 3,5-bis(diphenylphosphinothioyl)pyridine afforded new j3S,C,S-pincer palladium complexes with a r-bond
between Pd and 4C of the centered 3,5-pyridinediyl unit. By utilizing the quaternization and complexation ability of the pyridine imine
nitrogen (Npy) atom, various new pincer-type complexes, including hetero-binuclear complexes, have been synthesized.
Ó 2008 Elsevier B.V. All rights reserved.
Keywords: Pincer complex; Palladium; Pyridine; Quaternization; Binuclear complexes
1. Introduction
extension of the research, we have prepared new pincer
complexes of type (c) depicted in Scheme 1. Replacing
the centered phenylene unit in the pincer ligand by a pyri-
dine unit offers interesting possibilities. The presence of a
reacting and coordinating pyridine imine nitrogen (Npy)
atom will make it possible to create various new pincer
complexes derived from the complex of type (c). Examples
of such pincer ligands with a 3,5-pyridinediyl moiety, how-
ever, have been limited [5], because the presence of Npy
sometimes leads to a number of unexpected coordination
modes [5b]. Milstein et al. successfully demonstrated that
j3P,C,P-pincer rhodium and palladium complexes of a
monoanionic bis(phosphine)pyridine ligand, [3,5-(Ph2-
PCH2)2C5H2N]ꢀ, serve as a metalloligand for a second
metal center [5a]. We herein report the synthesis of a new
pincer complex of type (c) and the quaternization and com-
plexation reactions of the pincer complex.
Pincer palladium complexes have been intensively inves-
tigated in the field of catalysis and material science [1].
Self-assembled metallosupramolecules have also been the
subject of recent interest [2,3]. To construct metallosupra-
molecules of pincer complexes, the introduction of several
functional groups at the para-position of the centered arene
ring of pincer ligands (e.g., the pincer complex with struc-
ture (a) in Scheme 1) has been achieved [1a,1b,3]. Recently,
pincer complexes attached to terpyridine and porphyrin
units have also been synthesized, and their interesting
chemical properties have been revealed [3k,3l,3r].
We previously reported the preparation of pincer palla-
dium complexes with a centered phenylene-type ligand
bearing phosphine sulfide auxiliary ligands at the o-posi-
tions (cf. molecular formula (b) in Scheme 1) [4]. As an
2. Results and discussion
*
Corresponding author. Address: Tsukuba Research Center for Inter-
disciplinary Materials Science (TIMS), University of Tsukuba, 1-1-1
Tennoudai, Tsukuba 305-8573, Japan. Tel.: +81 29 853 5066; fax: +81 29
853 4490.
The Pd-catalyzed aryl phosphination of 3,5-dibromo-
pyridine with two equivalents of diphenylphosphine fol-
lowed by sulfurization with elemental sulfur afforded
E-mail address: kanbara@ims.tsukuba.ac.jp (T. Kanbara).
0022-328X/$ - see front matter Ó 2008 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2007.12.033

1110
H. Meguro et al. / Journal of Organometallic Chemistry 693 (2008) 1109–1116
F
Me
M
a
b
c
N
Ph2P
S
PPh2
S
Ph2P
S
PPh2
S
E
M
E
M
Scheme 1. Pincer complexes: E, chelating donor atom; F, Functional or
coordinating substituent.
ligand 1, as shown in Scheme 2 [4,6]. The pincer palladium
complex 2a was obtained via the ortho,ortho-cyclopallada-
tion of 1 with PdCl2(PhCN)2. The addition of sodium ace-
tate led to regioselective cyclopalladation at the 4C
position of the centered pyridine ring. The treatment of
2a with AgBF4 followed by the addition of Bu4NX
(X = Br, I) gave the corresponding bromo- (2b) and iodo-
(2c) complexes.
The chemical structures of 1 and 2a–c were confirmed by
NMR, FAB-mass spectroscopy, and elemental analysis. In
the 1H NMR spectrum of 2a, the signal assigned to the 4H
of the centered pyridine ring disappeared, and an upfield
shift (0.15 ppm) of the signal, assigned to the 2,6H of the
pyridine ring, was observed. The cyclopalladation led to
a downfield shift of the 13C NMR signal of Cipso by
37 ppm due to the r-bonding to Pd. The 31P NMR spec-
trum of 2a exhibited a downfield shift of the signal by
16 ppm due to the S-coordination mainly, and the two
phosphine sulfide groups were magnetically equivalent in
the complex. Evidence of S-coordination was also sup-
ported by the m(P@S) position of 2a (603 cmꢀ1), which
appeared at a lower frequency than that of 1 (645 cmꢀ1).
The ORTEP drawings of 1 and 2a are presented in
Fig. 1. Detailed results of X-ray crystallography and
selected bond lengths are summarized in Tables 1 and 2,
respectively. 2a has a distorted square-planar geometry,
and the Pd–C, Pd–S, and Pd–Cl bond lengths lie within
the range of lengths found in related pincer palladium com-
plexes [4]. The P@S bond lengths of 2a (2.003(3) and
Fig. 1. X-ray crystal structures of: (a) 1 and (b) 2a with thermal ellipsoids
drawn at the 50% probability level. Hydrogen atoms and solvated CHCl3
molecules are omitted for simplicity.
B in Scheme 3. A similar suggestion has been made for
j3S,P,S-pincer complexes composed of a phosphinine ring
bearing two phosphine sulfide side arms [7].
The treatment of 2b and 2c with alkylhalides afforded
Npy-quaternized pyridinium complexes 3–5 (see Scheme
1
4). The H NMR spectra of 3–5 were consistent with their
molecular structures. The 13C NMR spectra of 3–5 showed
the Pd–Cipso signal at a considerably lower field (d 212–206)
than those of 2b and 2c (d 186 for 2b and d 191 for 2c). The
Pd–Cipso signal position was at a lower magnetic field than
those of related Pd–pyridinium/pyridinylidene complexes
(d 178–190) [8] and similar to those of Pd-quinolin-4-yli-
dene complexes with a C@Pd+ bond (d 208–201) [9]. Con-
sequently, the NMR spectra of 3–5 are considered to have
a contribution from the resonance structure such as 3B in
Scheme 5.
˚
2.012(3) A) are somewhat longer, while the P–C bond
lengths of the phosphine sulfide and the centered pyridine
˚
ring in 2a (1.810(9) and 1.793(7) A) are shorter than those
˚
˚
of 1 (P–S, 1.9460(10) A; P–C, 1.814(2) A). A similar struc-
tural feature was observed for 2b and 2c; the ORTEP draw-
ings and detailed results of X-ray crystallography of 2b and
2c are given in Supplementary material. These data suggest
that the cyclopalladation leads to the delocalization of elec-
trons within the unsaturated part of the ligand, as shown in
X-ray quality single crystals of
3 and 5 were
obtained from their ion exchange with NH4PF6 to give
Br
Br
Ph2P
Ph2P
Ph2P
S
Ph2P
Ph2P
S
S
S
1) HPPh2,
[Pd], base
PdCl2(PhCN)2,
NaOAc
1) AgBF4
2) Bu4NX
N
N
N
Pd Cl
S
N
Pd X
S
2) S8
Ph2P
1
2a
2b: X = Br
2c: X = I
Scheme 2.

H. Meguro et al. / Journal of Organometallic Chemistry 693 (2008) 1109–1116
1111
Table 1
Crystal data and details of the structure refinements for 1, 2a, 30, 50, and 6
1
2a ꢁ 2CHCl3
30 ꢁ 2CH3CN
50 ꢁ CH3CN
6 ꢁ CHCl3
Formula
C29H23NP2S2
511.57
Monoclinic
C2/c (No. 15)
13.294(5)
C31H24Cl7NP2PdS2
891.18
Monoclinic
P21/c (No. 14)
9.2258(17)
C34H31F6IN3P3PdS2
985.98
C34H30BrF6N2P3PdS2
923.96
Monoclinic
P21/n (No. 14)
9.626(3)
C36H29Cl6NP2PdRuS2
1021.89
Monoclinic
P21/n (No. 14)
12.026(7)
Molecular weight
Crystal system
Space group
Triclinic
P1bar (No. 2)
7.284(3)
12.362(5)
22.099(10)
86.366(15)
88.584(14)
73.184(12)
1901.0(13)
2
˚
a (A)
˚
b (A)
16.697(6)
12.912(5)
22.234(3)
17.281(2)
14.511(4)
25.792(7)
29.677(14)
12.007(6)
˚
c (A)
a (°)
b (°)
c (°)
113.683(5)
105.338(7)
92.426(3)
111.341(9)
3
˚
V (A )
2624.6(17)
4
3.43
1.295
2670
2227
3418.6(9)
4
13.311
1.731
7612
3599.7(16)
4
19.384
1.705
8204
3992(4)
4
14.432
1.7
9054
6637
Z
l (cmꢀ1
)
15.958
1.722
7684
5631
Dcalc (g cmꢀ3
)
Number of unique reflections
Number of reflections measured
6349
4174
(I > 1.00r(I))
482
0.0441
(I > 1.00r(I))
0.0592
(I > 1.00r(I))
0.875
(I > 1.00r(I))
465
Number of variables
R1
169
0.0426
(I > 2.00r(I))
0.0595
(I > 2.00r(I))
1.066
391
0.112
(I > 2.00r(I))
0.1392
(I > 2.00r(I))
1.341
472
0.0434
(I > 2.00r(I))
0.0487
(I > 2.00r(I))
0.836
0.1398
(I > 1.00r(I))
0.1069
(I > 1.00r(I))
0.996
Rw
Goodness-of-fit
Table 2
0
0
˚
Selected bond lengths (A) for 1, 2a, 3 , 5 , and 6
˚
Bond length (A)
1
2a
30
50
6
Pd–Cipso
Pd–halogen
Pd–S
Pd–S
P–S
1.964(9)
2.390(2)
2.355(2)
2.344(2)
2.003(3)
2.012(3)
1.810(9)
1.793(7)
1.994(6)
2.6661(7)
2.3305(16)
2.3277(16)
2.018(2)
2.008(2)
1.808(5)
1.822(6)
1.502(9)
1.994(5)
2.4843(8)
2.3098(18)
2.3217(17)
2.010(2)
2.004(2)
1.809(6)
1.794(6)
1.502(8)
1.999(12)
2.399(3)
2.355(4)
2.399(3)
2.006(4)
2.018(3)
1.784(14)
1.784(13)
1.9460(10)
1.9460(10)
1.814(2)
P–S
C(bpy)–P
C(bpy)–P
Npy–C(sp3)a
1.814(2)
N
py–Ru
2.152(8)
2.408(3)
2.411(4)
Ru–Cl
Ru–Cl
a
Npy-quaternized substituent of 30 and 50.
Ph2P
Ph2P
S
Ph2P
Ph2P
S
S
S
S
1) R-X
2b,c
R N
Pd X X
S
N
N
Ph2P
A
Ph2P
B
3: R = Me, X = I (from 2c)
4: R = Benzyl, X = Br (from 2b)
5: R = σ-allyl, X = Br (from 2b)
Scheme 3. Delocalization of electron in the pincer ligand.
Scheme 4.
hexafluorophosphate salts, 30 and 50, respectively. Fig. 2
shows the ORTEP drawings of 30 and 50. Detailed results
of X-ray crystallography and selected bond lengths are
shown in Tables 1 and 2, respectively. The Pd–Cipso bond
˚
(2.006(11) A), respectively. The bond lengths are compara-
ble to those of the reported Pd–pyridinium/pyridinylidene
complexes [8b,8c] and the Pd–quinolin-4-ylidene complexes
with a C@Pd+ bond [9]. Raubenheimer et al. reported that
there is little difference between a Pd–quinolin-6-ylidene
0
0
˚
˚
lengths of 3 (1.994(6) A) and 5 (1.994(5) A) are slightly
˚
shorter than those of 2c (2.005(5) A) and 2b

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H. Meguro et al. / Journal of Organometallic Chemistry 693 (2008) 1109–1116
Ph2P
S
Ph2P
S
Ph2P
S
Cl
+
+
[RuCl2(η6-C6H6)]2
Me
N
Pd I
S
Me
N
Pd I
Ru N
Cl
Pd Cl
S
Ph2P
Ph2P
S
Ph2P
N
6
2a
3A
3B
Ph2P
S
Cl
PhCN Pt
Cl
PtCl2(PhCN)2
Scheme 5.
Pd Cl
S
Ph2P
7
Scheme 6.
Fig. 3. X-ray crystal structure of 6 with thermal ellipsoids drawn at the
50% probability level. Hydrogen atoms and a solvated CHCl3 molecule
are omitted for simplicity.
located in a piano-stool conformation, and the pincer frag-
ment of 6 maintains the same geometry, with bond lengths
and angles essentially similar to those of 2a, as shown in
˚
Table 2. The Ru–Npy bond length (Npy–Ru = 2.152(8) A)
falls within the range reported for related complexes such
as [RuCl2(g-1,3,5-Me3C6H3)(pyridine)] [11]. These results
indicate that 2a serves as an Npy-coordinating metalloli-
gand and does not change the basic structure of the con-
necting metal complexes upon coordination.
Fig. 2. X-ray crystal structures of: (a) 30 and (b) 50 with thermal ellipsoids
drawn at the 50% probability level. Hydrogen atoms, an PFꢀ6 anion, and
solvated CH3CN molecules are omitted for simplicity.
UV–Vis absorption data for the complexes are summa-
rized in Table 3, and the spectra are shown in Fig. S2. 2–5
have absorption bands in the region of 350–470 nm, and
the shape of the spectra in the region is similar to that of
reported pincer palladium complexes such as [3,5-bis(diph-
enylphosphinothioyl)toluene-C4,S,S0]chloropalladium(II)
(8, cf. Scheme 1b), in which the absorption bands have
been tentatively assigned to a metal-to-ligand charge-trans-
fer (MLCT) transition [4a]. The absorption band of 2a is
observed in an energy region that is about 20 nm lower
than that of 8, suggesting that replacing the centered phe-
nylene unit in the pincer ligand by a pyridine unit resulted
in a reduction in the energy level of the p* orbital of the
ligand. For complexes 2a (X = Cl, kmax,MLCT = 346 nm),
complex and a Pd–quinolin-6-yl complex in terms of the
Pd–C bond lengths [10].
The coordinating ability of the Npy atom of 2a allowed
the binding of 2a to other metal centers. The reactions of
2a with [RuCl2(g6-C6H6)]2 and [PtCl2(PhCN)2] led to the
formation of hetero-binuclear complexes, 6 and 7, respec-
tively, as exhibited in Scheme 6.
1
In the H NMR spectra of 6 and 7, the 2,6H signal of
the pyridine ring showed respective downfield shifts of
0.42 and 0.24 ppm from that of 2a. For 6, the signal of
H at g6-benzene was observed at d 5.43.
The ORTEP drawing of 6 is presented in Fig. 3. The
molecular structure reveals that the Ru(II) center of 6 is

H. Meguro et al. / Journal of Organometallic Chemistry 693 (2008) 1109–1116
1113
Table 3
Mass spectrometer. IR spectra were recorded on a JASCO
FT-IR-460Plus spectrometer. Elemental analyses were car-
ried out with a Yanaco CHN Corder MT-5 and a Yanaco
SX-Elements Micro Analyzer YS-10. UV–Vis absorption
spectra and emission spectra were recorded on a Shimadzu
UV–Vis absorption spectroscopic data for 1–8a
Absorption
k
max/ nm (e ꢂ 10ꢀ3/Mꢀ1 cmꢀ1
)
1
255 (29.8), 295 (5.8)
2a
2b
2c
3
263 (30.4), 301 (6.4), 346 (1.7)
263 (33.6), 309 (5.4), 352 (1.8)
262 (33.9), 309 (11.6), 392 (2.0)
361 (28.5), 370 (7.8), 405 (3.1)
257 (38.2), 324 (6.6), 367 (4.7)
254 (31.1), 324 (5.6), 363 (3.9)
262 (33.0), 302 (12.4), 405 (1.5)
264 (35.0), 304 (13.6), 400 (1.1)
265 (3.1), 323 (5.5)
UV-2550 spectrophotometer and
a Hitachi F-4500
fluorescence spectrophotometer, respectively. Dichlor-
obis(benzonitrile)palladium, PdCl2(PhCN)2 [13] and
dichlorobis(benzonitrile)platinum, PtCl2(PhCN)2 [14] were
prepared according to literatures. Benzeneruthenium(II)
chloride dimer, [RuCl2(g6-C6H6)]2, was purchased and
used as received.
4
5
6
7
8b
a
In CH2Cl2.
From Ref. [4a,b].
3.2. Synthesis of 3,5-bis(diphenylphosphinothioyl)pyridine
(1)
b
A mixture of 3,5-dibromopyridine (1.42 g, 6 mmol) and
diphenylphosphine (2.79 g, 15 mmol) was dissolved in
DMF (20 mL). Palladium chloride (53 mg, 0.3 mmol) and
sodium acetate (1.48 g, 18 mmol) were added to the solu-
tion, and the reaction mixture was stirred at 130 °C for
24 h under N2. After cooling to room temperature, sulfur
(480 mg, 15 mmol as elemental sulfur) was added and the
reaction mixture was stirred at 120 °C for 4 h under N2.
After cooling to room temperature, an aqueous solution
of EDTA-2Na (100 mL) and CHCl3 (200 mL) were added,
and the mixture was stirred for 30 min. The organic phase
was separated and the solvent was evaporated. The crude
product was purified by column chromatography and
recrystallization from THF to give 1 as a white powder
(1.96 g, 64% yield). FAB-mass: m/z = 512 [M+H]+. 1H
NMR (400 MHz in CDCl3): d 8.96 (ddd, J = 6.8 Hz,
2.3 Hz, 1.2 Hz, 2H), 8.19 (tt, J = 12.5 Hz, 2.0 Hz, 1H),
7.68–7.58 (m, 8H), 7.56–7.48 (m, 4H), 7.46–7.38 (m, 8H).
13C NMR (100 MHz in CDCl3): d 154.5 (d, J = 12.3 Hz),
142.9 (d, J = 9.1 Hz), 132.1, 132.0 (d, J = 11.5 Hz), 131.1
(d, J = 85.8 Hz), 129.9 (dd, J = 79.2 Hz, 4.0 Hz), 128.8
(d, J = 13.3 Hz). 31P NMR (160 MHz in CDCl3): d 39.2.
Anal. Calc. for C29H23NP2S2: C, 68.09; H, 4.53; N, 2.74;
S, 12.54. Found: C, 67.90; H, 4.73; N, 2.89; S, 12.12%.
2b (X = Br,
k
max,MLCT = 352 nm), and 2c (X = I,
k
max,MLCT = 392 nm), the peak position shifts in the
lower-energy direction with magnitude in the order of
Cl > Br > I; these data suggest that an enhancement in
the r-donor characteristic of the halide ligand stabilizes
the excited states [12]. The kmax,MLCT of the quaternized
complexes 3 (R = Me, X = I), 4 (R = CH2Ph, X = Br),
and 5 (R = CH2CH@CH2, X = Br) is observed at 405,
367, and 363 nm, respectively, which is shifted to longer
wavelength by about 20 nm than those of the iodide com-
plex 2c and the bromide complex 2b. These results indicate
that Npy-alkylation causes a bathochromic shift in the
MLCT band. The electron-withdrawing substitution
resulted in a reduction in the p* level, and the bathochro-
mic shift suggested that the Npy-alkylation slightly affects
the electron density of the metal [5a,5c]. For the Npy-coor-
dination (6 and 7), only a slight shift in the band was
observed, and the complexes exhibited absorption profiles
with long tails. 8 was light-emissive in the glassy frozen
state (kem = 590 nm, /f = 0.14, s = 240 ls) [4], whereas 2a
exhibited only weak emission in the glassy frozen state
(kem = 607 nm, /f = 0.01); the quaternization and coordi-
nation reactions of 2a did not improve the emission ability.
As described above, new pincer Pd complexes 2 with a
pyridine moiety have been prepared. Because of the quat-
ernizing and coordinating reactivity of Npy in 2, these com-
plexes are considered to be starting complexes for the
formation of various pincer complexes. The preparation
of a variety of hetero-binuclear pincer complexes would
be of interest because there have recently been extensive
studies on the catalytic reactions using the pincer palla-
dium complexes [1].
3.3. Synthesis of [3,5-bis(diphenylphosphinothioyl)pyridine-
C4,S,S0]chloropalladium(II) (2a)
A mixture of 1 (256 mg, 0.5 mmol), PdCl2(PhCN)2
(270 mg, 0.7 mmol), and sodium acetate (123 mg,
1.5 mmol) in 1,1,2,2-tetrachloroethane (30 mL) was stirring
at 150 °C for 24 h under N2. The resulting yellow precipi-
tate was filtered and washed with hexane, ether, methanol,
and water. The product was purified by recrystallization
from a mixture of CHCl3 and hexane to give a yellow pow-
der of 2a (88 mg, 27% yield). FAB-mass: m/z = 616
[MꢀCl]+. 1H NMR (400 MHz in CDCl3): d 8.04 (dd,
J = 3.4 Hz, 2.8 Hz, 2H), 7.87ꢀ7.76 (m, 8H), 7.68–7.61
(m, 4H), 7.60–7.50 (m, 8H). 13C NMR (100 MHz in
CDCl3): d 180.0, 150.9 (d, J = 18.5 Hz), 145.7 (dd,
J = 102.4 Hz, 13.3 Hz), 133.4, 132.4 (d, J = 12.0 Hz),
3. Experimental
3.1. General procedure
NMR spectra were recorded on JEOL JNM-EX-400
and Lambda-300 NMR spectrometer. Mass spectra were
recorded on JEOL JMS-700 and Shimadzu LCMS-2010

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H. Meguro et al. / Journal of Organometallic Chemistry 693 (2008) 1109–1116
129.3 (d, J = 13.3 Hz), 128.1 (d, J = 81.8 Hz). 31P NMR
(160 MHz in CDCl3): 55.4. Anal. Calc. for
NP2PdS2: C, 40.68; H, 2.84; N, 1.58. Found: C, 39.73; H,
2.92; N, 1.50%.
d
C29H22ClNP2PdS2: C, 53.39; H, 3.40; N, 2.15; S, 9.83.
Found: C, 53.33; H, 3.24; N, 2.20; S, 9.66%.
X-ray quality single crystals of 3 were obtained from ion
exchange of 3 with NH4PF6 to give the hexafluorophos-
phate salt of 3 (30).
3.4. Synthesis of [3,5-bis(diphenylphosphinothioyl)pyridine-
C4,S,S0]bromopalladium(II) (2b)
3.7. Synthesis of [N-benzyl-3,5-
bis(diphenylphosphinothioyl)pyridinium-C4,S,S0]
bromopalladium(II) bromide (4)
To a THF (1 mL) solution of 2a (9.8 mg, 0.015 mmol)
was added AgBF4 (5.0 mg, 0.026 mmol), and an addition
of Bu4NBr (32 mg, 0.1 mmol) led to precipitation of the
product. The precipitate was filtered and washed with
methanol and water. The product was purified by recrystal-
lization from a mixture of CHCl3 and hexane to give a yel-
low powder of 2b (5.1 mg, 49% yield). FAB-mass: m/z =
To a THF (5 mL) solution of 2b (9.1 mg, 0.013 mmol)
was added benzyl bromide (1 mL) and refluxed for 12 h.
The solvent was evaporated, and the residue was washed
with hexane, ether and water. The product was purified
by recrystallization from a mixture of CH3CN and ether
to give a yellow powder of 4 (8.7 mg, 77% yield). ESI-mass:
m/z = 787 [MꢀBr]+. HRMS: calcd for C36H29NBrP2PdS2:
787.9434. Found: 787.9395. 1H NMR (400 MHz in
DMSO-d6): d 9.18 (d, J = 7.3 Hz, 2H), 7.98–7.90 (m,
8H), 7.88–7.70 (m, 4H), 7.78–7.68 (m, 8H), 7.33 (m, 5H),
5.60 (s, 2H). 13C NMR (100 MHz in DMSO-d6): d 207.1,
146.7 (dd, J = 107.8 Hz, 15.9 Hz), 144.2 (d, J = 26.6 Hz),
134.5, 132.6 (d, J = 11.9 Hz), 129.7 (d, J = 13.3 Hz),
128.9, 128.8, 128.5, 127.8, 125.8 (d, J = 82.5 Hz), 62.6.
31P NMR (160 MHz in DMSO-d6): d 62.9.
1
616 [MꢀBr]+. H NMR (400 MHz in CDCl3): d 8.08 (dd,
J = 3.3 Hz, 3.0 Hz, 2H), 7.86–7.76 (m, 8H), 7.68–7.62 (m,
4H), 7.59–7.52 (m, 8H). 13C NMR (100 MHz in CDCl3):
d 186.0, 150.9 (d, J = 18.6 Hz), 145.1 (dd, J = 102.1 Hz,
13.3 Hz), 133.4, 132.4 (d, J = 11.9 Hz), 129.3 (d,
J = 11.9 Hz), 128.2 (d, J = 81.2 Hz). 31P NMR (160 MHz
in CDCl3): d 59.8. Anal. Calc. for C29H22BrNP2PdS2: C,
49.98; H, 3.18; N, 2.01; S, 9.20. Found: C, 50.02; H, 3.21;
N, 1.98; S, 9.23%.
3.5. Synthesis of [3,5-bis(diphenylphosphinothioyl)pyridine-
C4,S,S0]iodopalladium(II) (2c)
3.8. Synthesis of [N-allyl-3,5-
bis(diphenylphosphinothioyl)pyridinium-C4,S,S0]-
bromopalladium(II) bromide (5)
Similar procedure described above was adopted using
Bu4NI (37 mg, 0.1 mmol) to give 2c (5.7 mg, 52% yield).
FAB-mass: m/z = 616 [MꢀI]+. 1H NMR (400 MHz in
CDCl3): d 8.18 (dd, J = 3.1 Hz, 3.0 Hz, 2H), 7.83–7.72
(m, 8H), 7.66–7.60 (m, 4H), 7.57–7.50 (m, 8H). 13C
NMR (100 MHz in CDCl3): d 190.7, 150.6 (d, J =
18.5 Hz), 143.8 (dd, J = 102.0 Hz, 13.9 Hz), 133.4, 132.3
(d, J = 11.9 Hz), 129.4 (d, J = 11.9 Hz), 128.2 (d, J =
79.8 Hz). 31P NMR (160 MHz in CDCl3): d 68.6. Anal.
Calc. for C29H22INP2PdS2: C, 46.82; H, 2.98; N, 1.88; S,
8.62. Found: C, 49.55; H, 3.20; N, 1.88; S, 8.58%.
Similar reaction described above was carried out using
2b and allyl bromide to give 5 (6.8 mg, 64% yield). ESI-
mass: m/z = 738 [MꢀBr]+. HRMS: calcd for C32H27NBr-
1
P2PdS2: 737.9276. Found: 737.9210. H NMR (400 MHz
in DMSO-d6): d 9.03 (d, J = 5.6 Hz, 2H), 8.00–7.80 (m,
12H), 7.78–7.64 (m, 8H), 5.95–6.05 (m, 1H), 5.26 (d,
J = 11.0 Hz, 1H), 5.22 (d, J = 18.0 Hz, 1H), 5.02(s, 2H).
13C NMR (100 MHz in DMSO-d6): d 211.7, 146.3 (dd,
J = 105.1 Hz, 14.6 Hz), 144.2 (d, J = 23.9 Hz), 134.5,
132.5 (d, J = 11.9 Hz), 131.6, 129.7 (d, J = 13.3 Hz),
126.0 (d, J = 80.3 Hz), 120.6, 61.8. 31P NMR (160 MHz
in DMSO-d6): d 62.6.
3.6. Synthesis of [N-methyl-3,5-
bis(diphenylphosphinothioyl)pyridinium-C4,S,S0]
iodopalladium(II) iodide (3)
X-ray quality single crystals of 5 were obtained from ion
exchange of 5 with NH4PF6 to give the hexafluorophos-
phate salt of 5 (50).
To a THF (2 mL) solution of 2c (9.7 mg, 0.013 mmol)
was added CH3I (1 mL) and refluxed for 6 h. The solvent
was evaporated, and the residue was washed with CHCl3,
acetone and water. The product was purified by recrystal-
lization from a mixture of CH3CN and ether to give a yel-
low powder of 3 (7.4 mg, 64% yield). ESI-mass: m/z = 758
[MꢀI]+. 1H NMR (400 MHz in CD3CN): d 8.23 (dd,
J = 4.8 Hz, 2.2 Hz, 2H), 7.93–7.80 (m, 12H), 7.73–7.66
(m, 8H), 3.94 (s, 3H). 13C NMR (100 MHz in DMSO-
d6): d 206.3, 144.8 (d, J = 26.6 Hz), 144.4 (dd, J =
107.8 Hz, 15.9 Hz), 134.5, 132.5 (d, J = 11.9 Hz), 129.8
(d, J = 13.3 Hz), 125.9 (d, J = 80.9 Hz), 47.6. 31P NMR
(160 MHz in CD3CN): d 67.5. Anal. Calc. for C30H25I2-
3.9. Synthesis of dichloro(g6-benzene){[3,5-
bis(diphenylphosphinothioyl)pyridine-
C4,S,S0]chloropalladium(II)}ruthenium(II) (6)
To a THF (5 mL) solution of 2a (9.8 mg, 0.015 mmol)
was added [RuCl2(g6-C6H6)]2 (10.0 mg, 0.020 mmol), and
refluxed for 12 h. The solvent was evaporated, and the res-
idue was washed with ether and hexane. The product was
purified by recrystallization from CHCl3 to give a pale
brown powder of 6 (8.8 mg, 65% yield). FAB-mass: m/
1
z = 866 [MꢀCl]+. H NMR (400 MHz in CDCl3): d 8.46

H. Meguro et al. / Journal of Organometallic Chemistry 693 (2008) 1109–1116
1115
(dd, J = 5.3 Hz, 2.2 Hz, 2H), 7.90–7.80 (m, 8H), 7.70–7.50
(m, 12H), 5.43 (s, 6H). 31P NMR (160 MHz in CDCl3): d
56.2. Anal. Calc. for C35H28Cl3NP2PdRuS2: C, 46.58; H,
3.13; N, 1.55. Found: C, 45.74; H, 2.78; N, 1.50%. Because
of low solubility of 6 in CDCl3, satisfactory 13C NMR
spectrum has not been obtained.
quest/cif. Supplementary data associated with this article
can be found, in the online version, at doi:10.1016/
j.jorganchem.2007.12.033.
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The authors are grateful to Prof. K. Tanaka, Dr. R.
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Appendix A. Supplementary material
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data for 1, 2a ꢁ 2CHCl3, 2b ꢁ 2CHCl3, 2c ꢁ CHCl3, 30 ꢁ
2CH3CN, 50 ꢁ CH3CN and 6 ꢁ CHCl3. These data can be
obtained free of charge from The Cambridge Crystallo-
graphic Data Centre via www.ccdc.cam.ac.uk/data_re-
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