Firsts lysidinyl- and lysidinium-triphosphines Pd(II) complexes

Article abstract of DOI:10.1016/j.poly.2009.07.055

The preparation of first lysidinyl-triphosphine ligand (named Triphosline) is described in three steps which are first a Michael type addition of imidazolidine (or lysidine) to diethylvinylphosphonate, second a phosphonate reduction with LiAlH₄ and third an anti-Markovnikov radical addition of the primary phosphine to diphenylvinylphosphine. The Triphosline behaves as a tridentate P-coordinating ligand in palladium(II) complexes. The dangling lysidine function is then cleanly and totally alkylated by methyl iodide to lead to a new kind of lysidinium-triphosphine complexes. Subsequent anion exchange with TlPF₆ affords the first example of a chloride free lysidinium-triphosphine palladium complex which has been fully characterized by spectroscopic and analytical methods.

Full text of DOI:10.1016/j.poly.2009.07.055

Polyhedron 29 (2010) 601–605
Contents lists available at ScienceDirect
Polyhedron
journal homepage: www.elsevier.com/locate/poly
Firsts lysidinyl- and lysidinium-triphosphines Pd(II) complexes
*
Jacques Andrieu , Lydie Harmand, Michel Picquet
Institut de Chimie Moléculaire de l’Université de Bourgogne (ICMUB) – UMR 5260 CNRS, 9 Av. Alain Savary, 21078 Dijon, France
a r t i c l e i n f o
a b s t r a c t
Article history:
Available online 5 August 2009
The preparation of first lysidinyl-triphosphine ligand (named Triphosline) is described in three steps
which are first a Michael type addition of imidazolidine (or lysidine) to diethylvinylphosphonate, second
a phosphonate reduction with LiAlH4 and third an anti-Markovnikov radical addition of the primary
phosphine to diphenylvinylphosphine. The Triphosline behaves as a tridentate P-coordinating ligand in
palladium(II) complexes. The dangling lysidine function is then cleanly and totally alkylated by methyl
iodide to lead to a new kind of lysidinium-triphosphine complexes. Subsequent anion exchange with
TlPF6 affords the first example of a chloride free lysidinium-triphosphine palladium complex which
has been fully characterized by spectroscopic and analytical methods.
Keywords:
Triphosphine
Synthesis of polyphosphines
Imidazoline
Imidazole
Palladium complexes
Ó 2009 Elsevier Ltd. All rights reserved.
1. Introduction
catalysts in aldehydes decarbonylation [8] or increases the M–H
bond reactivity towards weakly polar carbonyl functions [9]. Imi-
The development of efficient continuous-flow catalytic systems
represents a major challenge in modern homogenous catalysis.
However, it requires a perfect immobilization, or sequestration,
of the catalytic species in one liquid phase while the organic prod-
ucts are continuously extracted from the catalytic medium by a
mobile phase [1]. For example, the association of a nonvolatile sol-
vent such as imidazolium salts with supercritical carbon dioxide
has given very good results in Rh catalyzed olefin hydroformyla-
tion [2] or in Ni catalyzed styrene hydrovinylation in continuous-
flow conditions [3]. Nevertheless, the performances of catalytic
processes can become even better by introduction on the coordi-
nated phosphines of a cationic imidazolium fragment which
strongly decreases the metal–phosphine leaching in the mobile
phase [4]. For example, an imidazolium monophosphine salt was
recently successfully employed in palladium alkynylation, plati-
num hydrogenation and rhodium hydroformylation catalysis in io-
nic liquids without metal leaching into the organic layer [5,6]. In
the same manner, addition of an imidazolium fragment to a
diphosphine has decreased the rhodium leaching in asymmetric
hydrogenation of phenylethenamine to traces level [4]. Addition-
ally, multi-phosphines, specially the [PhP(CH2CH2PPh2)2] ligand,
offer advantages over mono- or di-phosphines in homogeneous
catalysis. Indeed, the simultaneous coordination of three phospho-
rus atoms increases significantly the immobilizing behavior of
such ligand as well as the nucleophilic character of the metal cen-
tre. This favors the C–H bond oxidative addition to rhenium cata-
lysts in cyclooctane dehydrogenation [7] and to rhodium
dazolium-triphosphines are thus very appealing to perform the
above catalysis in continuous-flow conditions using an ionic liquid
and we have previously reported a synthetic method opening the
access to such unprecedented ligands [10], see Scheme 1.
However, in this previous work, we described only partial
N-alkylation reactions of imidazolyl-triphosphines despite the
use of different alkylating reagents [10]. Nevertheless, we empha-
size that complete conversion of neutral N-heterocycles to imi-
dazolium fragments is absolutely essential to render the related
tridentate ligand totally insoluble in an extracting mobile phase
and, therefore, to maintain the active species stable for a long per-
iod of time in the ionic liquid phase. We thus report now the sol-
vation of this problem of partial N-alkylation by the replacement
of the imidazole by a stronger nucleophile like an imidazoline.
2. Results and discussion
The procedure we have developed in the case of ligands 1a,b
[10] was thus applied to the 2-methylimidazoline 2 (also named
lysidine), see Scheme 2.
According to this procedure, the lysidinyl-phosphine 3 was suc-
cessfully prepared by a one pot synthesis including a Michael type
addition of 2 to diethylvinylphosphonate followed by the reduc-
tion of the phosphonate function of the intermediate lysidinyl-
phosphonate with LiAlH4
. The functionalized primary phosphine
3 was obtained in a moderate yield of 32%, identical to those found
for the analogous ligands 1a,b. The presence of the PH2 group is
confirmed in the phosphorus NMR spectrum by the existence of
a triplet of quintuplets at d = ꢀ149.70 ppm which is very similar
to d = ꢀ136.17 and ꢀ137.60 ppm found respectively for 1a and
* Corresponding author.
E-mail address: Jacques.Andrieu@u-bourgogne.fr (J. Andrieu).
0277-5387/$ - see front matter Ó 2009 Elsevier Ltd. All rights reserved.
doi:10.1016/j.poly.2009.07.055

602
J. Andrieu et al. / Polyhedron 29 (2010) 601–605
The further addition of a stoechiometric amount of ligand 4 to
PPh2
PPh2
[PdCl2(NCPh)2] in CH2Cl2 solution led to the air stable cationic pal-
ladium complex 5 (see Eq. (1)) which is characterized by a triplet at
d = 110.81 ppm and a doublet at d = 47.17 ppm with a 2J(P,P) cou-
pling constant of ca. 7 Hz and a 1:2 integration-ratio in its pro-
ton-decoupled phosphorus NMR spectrum. The phosphorus
chemical shifts as well as the phosphorus–phosphorus coupling
constant are very close to those reported in the literature for anal-
ogous unmodified- and modified-triphosphine cationic complexes
[PdCl(P3)]Cl with P3 = Triphos, Trisphosim or Triphosmim [10,11].
The molecular structure of 5 was definitely confirmed by a posi-
tive-mode electrospray ionization mass-spectrum which showed
the molecular peaks of the expected cationic palladium complex
(see Section 4 for details).
P
N
N
R
1a (R = H, Triphosim)
1b (R = Me, Triphosmim)
+ [PdCl2(NCPh)2]
CH2Cl2, 1 h
-
PPh2
Cl
+
P
Pd Cl
-
PPh
+
N
2 Cl
Ph2P
PPh2
PPh2
N
+ [PdCl2(NCPh)2]
CH2Cl2,12 h
Pd Cl
PPh2
P
+ BuCl
7 days
80 °C
N
P
N
(1)
-
PPh2
+
5
Cl
Me
4
Pd Cl
PPh2
P
N
Me
N
+
N
-
N
Cl
Bu
Since imidazoles are known to undergo a complete alkylation
reaction after two days in refluxing BuCl [12], we have applied sim-
ilar conditions to complex 5. As imidazolines are stronger nucleo-
philes than imidazoles due to their nitrogen lone pair which cannot
be delocalized on the N-heterocycle, we indeed anticipated that
such procedure would lead to a complete alkylation of 5. In this
case however, a mixture of several complexes was observed in pro-
ton-decoupled phosphorus NMR, resulting likely from a decompo-
sition of 5 in such reaction conditions whereas a clean but
incomplete alkylation reaction was previously observed with its
analogous Trisphosim palladium complex [10]. The same reaction
performed in neat boiling EtBr led also, after three days, to a mix-
ture of palladium complexes which could unfortunately not be
clearly identified due to their insolubility in common organic
N-alkylation limited to 76%
Scheme 1.
1b and with
a
typical high phosphorus–hydrogen coupling
constant of 195 Hz [10]. Addition of two equivalents of diphenylvi-
nylphosphine and 5% of AIBN to the air-sensitive ligand 3 followed
by heating at 105 °C for 20 h led to the new functionalized triphos-
phine ligand 4 (named Triphosline) in quantitative yield. Its proton-
decoupled phosphorus NMR spectrum confirms unambiguously
the formation of the two PCH2CH2P units by the unique presence
of a doublet at d = ꢀ13.00 ppm for the terminal P-atoms and a trip-
let at d = ꢀ25.38 ppm for the internal P-atom with a 2J(P,P) cou-
pling constant of 27 Hz.
solvents. Nevertheless, we finally succeeded to perform
a
O
(EtO)2P
PH2
O
(EtO)2P
Me
H
N
1) LiAlH4 in Et2O
N
N
Me
Me
reflux 18 h
+ tBuOK in
N
N
N
2) Hydrolysis
THF reflux 20 h
3 (32%)
not isolated
2
PPh2
PPh2
PPh2
+ 2
P
N
N
+ AIBN 5% mol
105°C, 20 h
Me
4
quantitative yield
(named Triphosline)
Scheme 2.

J. Andrieu et al. / Polyhedron 29 (2010) 601–605
603
quantitative alkylation reaction without formation of any decom-
position product by using a CH3I/CH2Cl2 mixture, as shown by
the presence of new signals at d = 109.25 and 46.78 ppm in the
proton-decoupled phosphorus NMR spectrum of the crude, corre-
sponding to the internal and external P-atoms, respectively. Be-
sides, the presence of the N-methyl group is confirmed by a new
signal at d = 42.2 ppm in the proton-decoupled carbon NMR spec-
trum, thus suggesting the presence of the alkylated derivative 6
(see Scheme 3). Since the phosphorus, proton and carbon chemical
shifts of compounds 5 and 6 are practically the same, an additional
characterization experiment was investigated in order to confirm
unambiguously the formation of this new cationic palladium
complex.
Interestingly, a positive-mode electrospray ionization mass
analysis of complex 6 was performed but did not show the ex-
pected molecular peak at m/z 362.06 for the dicationic palladium
species [M–Cl–I]2+ but another signal at m/z 408.05. This signal
has been unambiguously assigned through simulation as the dicat-
ionic species [M–2Cl] 2+ which subsequently contains a Pd–I cova-
lent bond instead of a Pd–Cl as anticipated in 6 (see Scheme 3).
Although this substitution of the chloride by the iodide anionic li-
gand was quite unexpected, it can be rationalized in terms of lower
electronegativity and thus better
r-donor character of the iodide
and has been previously reported for a similar complex containing
the Triphos ligand by simple addition of KI to the complex
[PdCl(Triphos)]Cl [13].
It is noteworthy that apart from the above strategy consisting in
protecting the phosphorus atoms through coordination to a transi-
tion metal in order to obtain the imidazolium- or imidazolinium-
triphosphine complexes, we also wished to obtain the free ligand
and therefore we explored a more direct synthetic method. Since
it is well known that the nitrogen atom is a better nucleophile cen-
ter than the phosphorus atom, the direct alkylation reaction of
imidazole-phosphine ligands should take place preferentially on
the imidazole moiety. However, in order to avoid the formation
of any mixture, our alternative synthesis consisted in protecting
the phosphorus atoms by oxidation prior to the alkylation reaction,
followed by a PV-atoms reduction to release the phosphine func-
tions. We indeed found that the addition of an excess of molecular
sulfur to ligand 1b [10] led to the complete formation of pure tri-
sulfide ligand 8 after 1 day at room temperature, see Scheme 4.
The further addition of methyl iodide in large excess allowed
the convert quantitatively ligand 8 to the expected compound 9
(see Scheme 4) after 3 days. Unfortunately, all attempts to depro-
tect the phosphorus atoms using either HMPT, LiAlH4 in refluxing
THF for 4 days or fresh Raney Ni in refluxing acetonitrile for 1
day remained unsuccessful.
Finally, the conversion of complex 7 to the corresponding halide
free palladium complex was investigated. Three equivalents of
AgNO3 or AgOTf were added to this complex in a CH2Cl2/MeOH
solution but this treatment unfortunately led to a mixture of palla-
dium complexes as shown by the existence of several signals in the
related proton-decoupled phosphorus NMR spectra of the crude
products. Nonetheless, when TlPF6 was used in a CH2Cl2/CH3CN
mixture, a selective and complete formation of a new palladium
complex was detected by the presence of only two new signals
at d = 115.04 and 49.16 ppm, respectively for the internal and
external P-atoms in addition to the PF6 signal. It is worth to men-
tion that the corresponding mass spectrum, recorded using the
electrospray technique, is unconsistent with the expected complex
11 as it is identical to the one obtained for the starting complex 7.
Indeed, the formation of 12 was instead observed as determined
from NMR and elemental analysis data (see Section 4). This latter
observation is likely the consequence of a selectivity in the halide
PPh2
-
Cl
+ CH3I
+
Pd Cl
P
5
N
+
in CH2Cl2
60 h
PPh2
N
-
Me
I
6
Me
not observed by ESI-MS
intramolecular
halides exchange
-
2 Cl
PPh2
+
Pd
I
P
N
+
PPh2
N
Me
Me
7
Scheme 3.
Ph2
P=S
P=S
+ S8, 24 h
N
1b (Triphosmim)
P=S
Ph2
N
Me
(91%)
8
Ph2
P=S
+ CH3I
PPh2
PPh2
P=S
P
+
N
I
Me
P=S
Ph2
N
-
+
N
Me
N
-
I
Me
Me
10
(94%)
9
Scheme 4.

604
J. Andrieu et al. / Polyhedron 29 (2010) 601–605
peaks (1H and 13C{1H}) or downfield of external 85% H3PO4 in
-
water (31P). Electrospray mass-spectra of palladium complexes
were performed on Bruker micrOTOF-Q instrument. Elemental
analyses were carried out by the analytical service in our labora-
tory with a Fisons Instruments EA1108 analyzer. The commercial
compounds CH3I, S8, 2-methylimidazoline (also named lysidine),
PPh2
+
Cl
Pd
I
P
N
+
PPh2
N
-
Me
Cl
Me
diphenylvinylphosphine,
diethylvinylphosphonate,
LiAlH4,
7
AIBN [2,2-azobis(2-methyl-propionitrile)], AgNO3, TlPF6 and
[PdCl2(NCPh)2)] were used as received. The Triphosmim 1a and
Triphosmim 1b ligands have been prepared according to the proce-
dure described in the literature [10].
-
3 PF6
+ TlPF6 (in excess)
in CH2Cl2
PPh2
+
Pd NCMe
PPh2
P
4.2. Synthesis of ligands and complexes
N
+
N
Me
Me
4.2.1. Synthesis of 2-methyl-1-(2-phosphinoethyl)-imidazoline 3
Me
11
A
mixture of 2-methylimidazoline or lysidine (1.485 g,
-
17.66 mmol), diethylvinylphosphonate (2.889 g, 17.61 mmol) and
30 mL of THF was treated with tBuOK (0.286 g, 2.55 mmol) and
heated in refluxing THF for 21 h. The solvent was removed under
vacuum and the yellow residue obtained was dried for 1 h at
70 °C. The residue was then cooled at 0 °C and 90 mL of Et2O and
LiAlH4 (1.266 g, 33.3 mmol) were rapidly added. A strong gas evo-
lution was immediately observed with an increase of the temper-
ature. When the exothermic reaction was subsided, the Et2O
mixture was refluxed for 19 h. The grey suspension was cooled
down to room temperature and hydrolyzed by 15 mL of deoxygen-
ated water. The organic phase was separated and the aqueous solu-
tion was extracted twice with 20 mL of Et2O. The combined organic
layers were dried over K2SO4 and filtered. Evaporation of the sol-
vent led to a colorless viscous oil which was dried under vacuum
2 PF6
PPh2
+
Pd
I
P
N
+
PPh2
N
Me
12
Scheme 5.
abstraction reaction induced by a strong covalent character of the
Pd–I bond (See Scheme 5). Other halide abstracting reagents and/
or other strategies are currently in progress in our group in order
to get totally halide-free lysidinium-triphosphine palladium com-
plexes which would be better suitable for further studies in homo-
geneous catalysis.
for 2 h at room temperature (0.819 g, 32%). 1H NMR
(CDCl3) = 3.59 (t, 2H, C(4/5)H2–N, J(H,H) = 9.5 Hz), 3.20 (t, 2H,
(5/4)H2–N, J(H,H) = 9.5 Hz), 3.16 (m, 2H, CH2N), 2.56 (dt, 2H, PH2,
d
C
J(P,H) = 195 Hz, 3J(H,H) = 7.8 Hz), 1.86 (s, 3H, CH3), 1.62 (m, 2H,
CH2P). 13C{1H} NMR d (CDCl3) = 163.90 (s, 1C, NCN), 51.94 (s, 1C,
CH2(N@C)), 49.71 (s, 1C, CH2(N–C)), 49.50 (s, 1C, CH2N), 14.37 (s,
1C, CH3), 13.52 (d, 1C, CH2P, J(P,C) = 10.7 Hz). 31P{1H} NMR
d = ꢀ149.70 (s, 1P), 31P NMR d (CDCl3) = ꢀ149.70 (tquint., 1P,
J(P,H) = 195 Hz, 2J(P,H) = 3J(P,H) = 5.5 Hz).
3. Conclusion
In this paper, we have described the preparation of the first
lysidinyl-triphosphine (Triphosline) in three steps comprising an
addition of 2-methylimidazoline to vinylphosphonate followed
by a reduction of the PV-atom to primary phosphine and its addi-
tion of diphenylvinylphosphine. With the aim to get the related
lysidinium-triphosphine salts for further studies in homogenous
catalysis, we have clearly shown that the higher nucleophilic char-
acter of the lysidine fragment compared to imidazole, together with
a prior coordination to a palladium(II) complex, allows to perform
a clean N-alkylation reaction using methyl iodide. Since the new
cationic functionalized triphosphines thus obtained are very
appealing as a new family of immobilizing ligands in transition
metal catalysis due to the simultaneous presence of three strongly
coordinating P-centers and a stable cationic fragment, we are cur-
rently investigating the catalytic properties of their metal com-
plexes in our laboratory.
4.2.2. Synthesis of 1-{2-[Bis-(2-diphenylphosphinoethyl)-phosphino]-
ethyl}-2-methylimidazoline 4 named Triphosline
A mixture of ligand 7 (0.136 g, 0.943 mmol), diphenylvinyl-
phosphine (0.418 g, 1.97 mmol) and AIBN (9 mg, 0.05 mmol,
equivalent to 5% mol/mol) was heated at 105 °C for 22 h. Ligand
4 was purified by heating at 180 °C under vacuum for 1 h and ob-
tained as a yellow-orange waxy oil (0.536 g, quantitative yield). 1H
NMR
C
d (CDCl3) = 7.33–7.18 (m, 20H aromatics), 3.53 (t, 2H,
(4/5)H2–N, J(H,H) = 9.7 Hz), 3.12 (t, 2H, C(5/4)H2–N, J(H,H) = 9.7 Hz),
2.99 (m, 2H, CH2N), 1.96 (m, 4H, CH2PPh2), 1.75 (s, 3H, CH3), 1.41
(m, 6H, P(CH2)3). 13C{1H} NMR d (CDCl3) = 164.35 (s, 1C, NCN),
138.13–128.44 (m, 24C, aromatics), 51.09 (s, 1C, CH2(N@C)),
49.72 (s, 1C, CH2(N–C)), 44.30 (d, 1C, CH2N, 2J(P,C) = 21.8 Hz),
25.88 (d, 1C, CH2P(CH2)2, J(P,C) = 16.7 Hz), 23.66 (t, 2C, CH2PCH2–
CH2, J(P,C) = 2J(P0,C) = 15 Hz with
P and P’ respectively for
4. Experimental section
CH2P(CH2)2 and CH2PPh2, similar to Triphosmim ligand [10]),
21.99 (t, 2C, CH2PPh2, J(P0,C) = 2J(P,C) = 15 Hz), 14.18 (s, 1C, CH3).
31P{1H} NMR d (CDCl3) = ꢀ13.00 (d, 2P, 2J(P,P) = 26.9 Hz), ꢀ25.38
(t, 1P, 2J(P,P) = 27.0 Hz).
4.1. General procedures and instrumentation
All manipulations were carried out under purified argon using
standard Schlenk techniques. All solvents were dried and deoxy-
genated prior to use by standard methods. Standard NMR mea-
surements (1H, 13C{1H} and 31P{1H}) were carried out with a
Bruker Avance 300 spectrometer at room temperature in CDCl3
solution. The peak positions are reported with positive shifts in
ppm downfield of TMS as calculated from the residual solvent
4.2.3. Synthesis of palladium(II) complex 5
To a red suspension of [PdCl2(NCPh)2] (0.228 g, 0.594 mmol) in
5 mL of CH2Cl2 was slowly added a solution of ligand 4 (0.338 g,
0.594 mmol) in 5 mL of CH2Cl2. An orange suspension was imme-
diately formed which became a clear orange solution after about 15
min at room temperature. After stirring for 12
h at this

J. Andrieu et al. / Polyhedron 29 (2010) 601–605
605
temperature, the solution was filtered over CeliteÒ and the solvent
was removed under vacuum. An orange powder was obtained
which was washed twice with 10 mL of Et2O and dried under vac-
uum at room temperature for 5 h (0.418 g, 94%). 1H NMR d
(CDCl3) = 7.91–.22 (m, 20H aromatics), 3.44 (m, 4H, C(4+5)H2–N),
3.36–2.40 (m, 12H, 5 CH2P plus CH2N), 1.69 (s, 3H, CH3). 13C{1H}
NMR d (CDCl3) = 165.13 (s, 1C, NCN), 133.16–127.61 (m, 24C, aro-
matics), 50.19 (s, 1C, CH2(N@C)), 48.80 (s, 1C, CH2(N–C)), 44.47 (s,
br, 1C, CH2N), 29.57 (s, br, 3C, P(CH2)3), 27.59 (s, br, 2C, CH2PPh2),
@CH0N), 4.51 (m, 2H, CH2N), 3.71 (s, 3H, N–CH3), 2.80 (m, 4H,
CH2PPh2), 2.71 (s, 3H, CH3C), 2.60 (m, 2H, CH2P(CH2)2), 2.01 (m,
4H, CH2P(CH2)2). 13C{1H} NMR d (CDCl3) = 143.33 (s, 1C, NCN),
130.94–120.80 (m, 24C aromatics plus 2C from @CHN), 41.89 (s,
1C, CH2N), 35.30 (s, 1C, N–CH3), 29.92 (d, 1C, CH2P(CH2)2,
J(P,C) = 48 Hz), 24.70 (d, 2C, CH2PCH2–CH2, J(P,C) = 52 Hz), 23.41
(d, 2C, CH2PPh2, J(P,C) = 50 Hz), 11.09 (s, 1C, CH3). 31P{1H} NMR d
(CDCl3) = 51.47 (part
B ,
of AA0B spin system, 1P, Pinternal
2
A0
2J(PA,PB) = 54 Hz and J(P ,PB) = 57 Hz), 45.00 (part A of AA0B spin
12.59 (s, 1C, CH3). 31P{1H} NMR
d (CDCl3) = 110.81 (t, 1P,
system, 1P, PAterminal, 2J(PA,PB) = 54 Hz and part A0 of AA0B spin sys-
0
0
2J(P,P) = 6.8 Hz), 47.17 (d, 2P, 2J(P,P) = 6.8 Hz). ESI-MS (positive
mode, CH2Cl2) found for C34H39N2P3PdCl2 (744.073) m/
z = 709.114 [MꢀCl]+ and m/z = 354.562 [M+HꢀCl]2+. Simulated:
m/z = 709.105 and m/z = 354.552. Anal. Calc. for C34H39N2P3PdCl2:
C, 54.74; H, 5.27; N, 3.75. Found: C, 54.67; H, 5.56; N, 3.91%.
tem, 1P, PA
,
2J(PA ,PB) = 57 Hz). Anal. Calc. for C35H40N2P3S3I
terminal
(M = 804.73): C, 52.24; H, 5.01; N, 3.48. Found: C, 52.66; H, 4.86;
N, 3.39%.
4.2.7. Synthesis of palladium(II) complex 12
To a mixture of 7 (0.123 g, 0.139 mmol) and thallium hexa-
fluorophosphate (0.148 g, 0.424 mmol) were added 7 mL of dichlo-
romethane. The deep orange suspension was stirred at room
temperature for 3 h and then filtered. Evaporation of the solvent
led to an orange powder which was washed with Et2O and dried
under vacuum (0.139 g, 91%). 1H NMR d (DMSO) = 7.92–7.52 (m,
20H, aromatics), 3.88 (s, 3H, CH3N), 3.81–2.74 (m, 16H, N(CH2)3
plus 5 PCH2), 2.19 (s, 3H, CH3). 13C{1H} NMR d (DMSO) = 167.00
(s, 1C, NCN), 134.65–129.84 (m, 24C, aromatics), 50.43 (s, 1C,
4.2.4. Synthesis of palladium(II) complex 7
To a solution of complex 5 (0.090 g, 0.121 mmol) in 6 mL of
CH2Cl2 was added CH3I (0.3 mL, 3.20 mmol). The resulting clear or-
ange solution was stirred for 60 h. It is worth to note that an orange
suspension started to appear after about 12 h. The solvent was re-
moved under vacuum and an orange powder was obtained which
was dried under vacuum at room temperature for 2 h (0.107 g,
quantitative yield). 1H NMR d (CD3CN) = 7.90–7.24 (m, 20H aro-
matics), 3.62–2.61 (m, 19H, CH3N plus 5 PCH2 plus N(CH2)3),
1.74 (s, 3H, CH3). 13C{1H} NMR d (CD3CN) = 166.89 (s, 1C, NCN),
134.14–128.03 (m, 24C, aromatics), 49.53 (s, 1C, C(4/5)H2–N),
48.21 (s, 1C, C(5/4)H2–N), 46.69 (s, br, 1C, CH2N), 42.21 (s, br, 1C,
CH3N), 31.82 (s, br, 3C, P(CH2)3), 26.48 (s, br, 2C, CH2PPh2), 12.06
(s, 1C, CH3). 31P{1H} NMR d (CD3CN) = 109.25 (s, br, 1P), 46.78 (s,
br, 2P). ESI-MS (positive mode, CH2Cl2) found for C35H42N2P3PdCl2I
(866.001) m/z = 408.0515 [Mꢀ2Cl]2+, simulated: 408.0321. Anal.
Calc. for C35H42N2P3PdCl2I: C, 64.20; H, 6.01; N, 4.28. Found: C,
63.86; H, 6.24; N, 4.37%.
C
(4/5)H2–N), 49.43 (s, 1C, C(5/4)H2–N), 47.42 (s, 1C, CH2N), 42.29
(s, 1C, CH3–N), 36.68 (s, 3C, P(CH2)3), 34.34 (s, 2C, CH2PPh2),
11.25 (s, 1C, CH3). 31P{1H} NMR
d (DMSO) = 115.04 (t, 1P,
2J(P,P) = 4.9 Hz), 49.16 (d, 2P, 2J(P,P) = 4.9 Hz), ꢀ144.18 (hept., 1P,
J(P,F) = 711 Hz). ESI-MS (positive mode, CH2Cl2/MeOH) found for
C35H42N2P5PdF12
lated: 408.0321. Anal. Calc. for C35H42N2P5PdF12I: C, 37.97; H,
I
(1105.99) m/z = 408.0309 [Mꢀ2PF6]2+
, simu-
3.83; N, 2.53. Found: C, 37.54; H, 3.69; N, 2.66%.
Acknowledgments
4.2.5. Synthesis of 8 (Triphosmim trisulfide)
We wish to acknowledge the Ministère de l’Enseignement
Supérieur et de la Recherche, the Université de Bourgogne, the Cen-
tre National de la Recherche Scientifique and the Conseil Régional
de Bourgogne for support of this work. We also thank Miss M.-J.
Penouilh (Université de Bourgogne) for her technical assistance
and discussion in the electrospray analyses of palladium
complexes.
To a mixture of ligand Triphosmim 1b (0.270 g, 0.476 mmol) and
S8 (0.055 g, 1.71 mmol) were added 10 mL of dichloromethane. The
resulting colorless solution was stirred at room temperature for 24
h. Evaporation of solvent led to a white powder which was dried
under vacuum for 1 h (0.287 g, 91%). 1H NMR d CDCl3 = 7.76–7.19
(m, 20H aromatics), 6.73 (s, 1H, @CHN), 6.72 (s, 1H, @CH0N), 4.15
(m, 2H, CH2N), 2.48 (m, 4H, CH2PPh2), 2.15 (s, 3H, CH3), 2.13 (m,
4H, CH2P(CH2)2), 1.92 (m, 2H, CH2P(CH2)2). 13C{1H} NMR
d
References
CDCl3 = 143.39 (s, 1C, NCN), 131.01–117.84 (m, 24C aromatics plus
2C from @CHN), 38.66 (s, 1C, CH2N), 30.93 (d, 1C, CH2P(CH2)2,
J(P,C) = 48 Hz), 25.11 (d, 2C, CH2PCH2–CH2, J(P,C) = 54 Hz), 23.40
(d, 2C, CH2PPh2, J(P,C) = 50 Hz), 12.22 (s, 1C, CH3). 31P{1H} NMR d
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CDCl3 = 50.18 (part
B
of AA0B spin system, 1P, Pinternal
,
2
A0
2J(PA,PB) = 54 Hz and J(P ,PB) = 57 Hz), 44.33 (part A of AA0B spin
system, 1P, PAterminal, 2J(PA,PB) = 54 Hz and part A0 of AA0B spin sys-
0
0
tem, 1P, PA
,
2J(PA ,PB) = 57 Hz). Anal. Calc. for C34H37N2P3S3
terminal
(M = 662.79): C, 61.61; H, 5.63; N, 4.22. Found: C, 60.94; H, 5.51;
N, 4.12%.
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4.2.6. Synthesis of 9 (Imidazolium–Triphosmim trisulfide iodide salt)
To a solution of 8 (1.000 g, 1.509 mmol) in 10 mL of CH2Cl2 was
added CH3I (2 mL, 21.35 mmol). The resulting solution was stirred
for 3 days at room temperature. The solvent was removed under
vacuum, leaving a yellow powder which was washed twice with
10 mL of Et2O and dried under vacuum for 2 h (1.143 g, 94%). 1H
NMR d (CDCl3) = 7.89–7.21 (m, 20H aromatics plus 2H from