Palladium(II) complexes with the mixed-donor ligand CH3S-(CH2)3-PPh2 crystal structures of [PdCl2{CH3S-(CH2)3-PPH 2}n] (n = 1, 2)

Article abstract of DOI:10.1002/1521-3749(200206)628:6<1433::AID-ZAAC1433>3.0.CO;2-H

The phosphorus-sulfur ligand 1-(methylthio)-3-(diphenyl-phosphino)-propane (S-P3) has been synthesized and characterized by ¹H NMR and ¹³C NMR. Reactions of S-P3 with [PdCl₂(PhCN)₂] afforded the complexes [PdCl₂(S-P3)] (I) and [PdCl₂(S-P3)₂] (II), in which S-P3 acts as a bidentate and monodentate ligand, respectively. Compound I crystallizes in monoclinic space group P2₁/n (No. 14) with cell dimensions: a = 8.589(3), b = 15.051(3), c = 17.100(3) A, β = 102.91(2)°, V = 2154.7(9) A³, Z = 4. Likewise, compound II crystallizes in monoclinic space group P2₁/n (No. 14) with a = 9.993(5), b = 8.613(4), c = 18.721(5) A, β = 90.18(3)°, V = 1611.3(12)A³, Z = 2. Compound II has a trans square planar configuration with only the P-site of the ligand bonded to the palladium atom.

Full text of DOI:10.1002/1521-3749(200206)628:6<1433::AID-ZAAC1433>3.0.CO;2-H

Palladium(II) Complexes with the Mixed-Donor Ligand CH3S-(CH2)3-PPh2
Crystal Structures of [PdCl2{CH3S-(CH2)3-PPh2}n] (n ؍ 1, 2)
Ehab M. Al-Shamia, Adnan S. Abu-Surrahb, Martti Klingac, and Hamdallah A. Hodalia,*
a Amman/Jordan, Department of Chemistry, Faculty of Science, University of Jordan
b Zarqa/Jordan, Department of Chemistry, Hashemite University
c Helsinki/Finland, Laboratory of Inorganic Chemistry, University of Helsinki
Received December 4th, 2001.
Abstract. The phosphorus-sulfur ligand 1-(methylthio)-3-(diphenyl-
phosphino)-propane (S-P3) has been synthesized and characterized
by 1H NMR and 13C NMR. Reactions of S-P3 with
[PdCl2(PhCN)2] afforded the complexes [PdCl2(S-P3)] (I) and
[PdCl2(S-P3)2] (II), in which S-P3 acts as a bidentate and monoden-
tate ligand, respectively. Compound I crystallizes in monoclinic
4. Likewise, compound II crystallizes in monoclinic space group
˚
P21/n (No. 14) with a ϭ 9.993(5), b ϭ 8.613(4), c ϭ 18.721(5) A,
3
˚
β ϭ 90.18(3)°, V ϭ 1611.3(12) A , Z ϭ 2. Compound II has a
trans square planar configuration with only the P-site of the ligand
bonded to the palladium atom.
space group P21/n (No. 14) with cell dimensions: a ϭ 8.589(3), b ϭ
15.051(3), c ϭ 17.100(3) A, β ϭ 102.91(2)°, V ϭ 2154.7(9) A , Z ϭ
Keywords: Palladium; Mixed-donor ligands; Phosphorus-sulfur li-
gands; Crystal structure
3
˚
˚
Palladium(II)-Komplexe mit dem zweifachen Donor-Liganden CH3S؊(CH2)3؊PPh2
Kristallstruktur von [PdCl2{CH3S؊(CH2)3؊PPh2}n] (n ؍ 1, 2)
˚
Inhaltsübersicht. Der Phosphor-Schwefel-Ligand 1-(Methylthio)-3-
(diphenylphosphino)propan (S-P3) wurde synthetisiert und durch
1H- und 13C-NMR-Spektroskopie charakterisiert. Die Reaktionen
von S-P3 mit [PdCl2(PhCN)2] führen zu den Komplexen [PdCl2(S-
P3)] (I) und [PdCl2(S-P3)2] (II), in denen S-P3 als zweiz"hniger bzw.
einz"hniger Ligand fungiert. Verbindung I kristallisiert monoklin
in der Raumgruppe P21/n (Nr. 14) mit den Zelldimensionen a ϭ
8,589(3), b ϭ 15,051(3), c ϭ 17,100(3) A, β ϭ 102,91(2)°, V ϭ
3
˚
2154,7(9) A , Z ϭ 4. II kristallisiert ebenfalls monoklin in der
Raumgruppe P21/n (Nr. 14) mit a ϭ 9,993(5), b ϭ 8,613(4), c ϭ
18,721(5) A, β ϭ 90,18(3)°, V ϭ 1611,3(12) A , Z ϭ 2. Verbindung
II hat eine quadratisch-planare trans-Konfiguration, in der die Li-
gand-Moleküle nur über das P-Atom an das Palladium-Atom ge-
bunden sind.
3
˚
˚
1 Introduction
In the last two decades many PdII-based catalysts were suc-
cessfully utilized in the synthesis of alternating aliphatic po-
lyketones [1Ϫ4]. The mechanism for the copolymer chain
growth involves migratory CO insertion into Pd-alkyl bond
of the growing polymer chain, followed by migratory alkene
insertion into the resulting Pd-acyl bond [5Ϫ7]. These steps
depend on the relative stability of the complex and complex
intermediates, which are directly affected by the donor/ac-
ceptor ability of the coordinating ligands. Recently, some
palladium(II) complexes with phosphorus-sulfur mixed-do-
nor bidentate ligands have shown catalytic activity towards
cyclic olefin polymerization [8Ϫ10]. In this paper we report
on the synthesis and characterization of a phosphorus-sul-
fur mixed-donor ligand (S-P3) with propylene backbone.
Acting as a chelating ligand, S-P3 forms a six-membered
Fig. 1 Structure of the complexes [PdCl2(S-P3)] (I) and [PdCl2(S-
P3)2] (II).
ring with the metal atom, and that enhances its ability to
form five coordinated species as compared with comparable
ligands having ethylene backbone [7,11]. The palladium
complexes, [PdCl2(S-P3)](I) and [PdCl2(S-P3)2] (II), have
been prepared and fully characterized and the single crystal
X-ray structures of both complexes were determined.
* Prof. H. A. Hodali
Department of Chemistry, Faculty of Science
University of Jordan
2 Results and Discussion
The phosphorus-sulfur ligand, S-P3, was prepared by the
reaction of 1-(methylthio)-3-chloropropane with sodium di-
Amman / Jordan
E-mail: h-hodali@sci.ju.edu.jo
Z. Anorg. Allg. Chem. 2002, 628, 1433Ϫ1436  WILEY-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002 0044Ϫ2313/02/628/1433Ϫ1436 $ 20.00ϩ.50/0
1433

E. M. Al-Shami, A. S. Abu-Surrah, M. Klinga, H. A. Hodali
˚
phenylphosphide in liquid ammonia following literature
procedures [12]. The colorless liquid obtained was purified
by repeated vacuum distillation. The ligand was fully cha-
racterized by 1H NMR and 13C NMR spectroscopy. The 1H
NMR spectrum of S-P3 shows, in addition to the aromatic
signals, a singlet at δ ϭ 2.01 (-SCH3), a triplet at δ ϭ 2.55
(-SCH2-), a multiplet at δ ϭ 1.72 (-CH2-), and another mul-
tiplet at δ ϭ 2.12 (-PCH2-). Reaction of S-P3 with equimo-
lar amount of [PdCl2(PhCN)2] in benzene gave complex I
in which the ligand acts as a bidentate ligand. However,
when the ligand is allowed to react with [PdCl2(PhCN)2] in
a 2:1 molar ratio, complex II was obtained. Both complexes
are nonelectrolytes as shown by their molar conductivity in
acetone (I: ΛM ϭ 1.7 S.cm2 · molϪ1; II: ΛM ϭ 8.8 S.cm2
· molϪ1). The two complexes are soluble in chloroform and
dichloromethane and insoluble in diethyl ether. However,
they differ in their solubility in benzene and THF, in which
only compound II is soluble. Both complexes were charac-
Table 1 Selected bond lengths /A and angles /° for complexes I
and IIa.
[PdCl2(S-P3)] (I) · CH2Cl2
[PdCl2(S-P3)2] (II)
Pd1-Cl1
Pd1-Cl2
Pd1-P1
Pd1-S1
P1-C5
P1-C11
P1-C3
S1-C1
2.3088(11)
Pd1-Cl1
Ϫ
Pd1-P1
Ϫ
P1-C1
P1-C7
P1-C13
S1-C15
2.3017(11)
2.3218(10)
2.3893(9)
2.2248(9)
2.2885(11)
1.821(3)
1.816(3)
1.819(3)
1.808(3)
1.803(4)
92.17(4)
87.25(4)
175.36(3)
171.70(3)
96.69(4)
83.57(4)
1.817(3)
1.819(3)
1.837(3)
1.796(4)
1.806(4)
S1-C4
S1-C16
Cl1-Pd1ϪCl2
Cl1-Pd1ϪP1
Cl1-Pd1-S1
P1-Pd1ϪCl2
P1-Pd1-S1
S1-Pd1ϪCl2
Cl1-PdϪCl1a
Cl1-PdϪP1
Cl1-Pd-P1a
Cl1aϪPdϪP1a
ϪϪϪϪ
ϪϪϪϪ
180.0
90.26(4
89.74(4)
90.26(4)
a) Atom lable ’a’ indicates a symmetry equivalent atom at 1Ϫx, Ϫy, Ϫzϩ1.
1
terized by elemental microanalysis and H NMR spectros-
1
copy. In the H NMR spectrum of [PdCl2(S-P3)2], a singlet
at δ ϭ 1.66 (-SCH3), and three multiplets at δ ϭ 2.25
(-CH2S-), δ ϭ 1.84 (-CH2-), and δ ϭ 2.57 (-PCH2-) were
observed. The aromatic protons were observed at δ ϭ
7.82Ϫ7.00. The bidentate coordination mode of S-P3 in the
complex I was clearly demonstrated by comparison of its
1H NMR spectrum with that for complex II. With the ex-
ception of the 1H NMR signal due to the protons of
-PCH2- group, all signals were shifted up field. For exam-
ple, the signal of the methyl protons (-SCH3) was shifted by
about 0.9 ppm upon sulfur coordination to the Pd-atom.
These results are consistent with the bidentate coordination
mode of S-P3 in compound I and unidentate mode in com-
pound II. Lability of the sulfur donor site was tested by
reacting equimolar quantities of compound I and S-P3
which leads to the formation of compound II.
Fig. 2 ORTEP plot of the molecular structure of compound I.
Thermal ellipsoids are drawn at the 30% probability level; solvent
molecule is omitted.
2.1 Crystal structures of [PdCl2(S-P3)] (I) and
[PdCl2(S-P3)2] (II).
Compound I crystallized from dichloromethane/diethyl
ether solvent mixure with one molecule of dichloromethane.
A yellow crystal of the dimensions 0.40 ϫ 0.38 ϫ 0.35 mm
was analyzed to give the structure shown in Figure 2. Se-
lected bond lengths and bond angles are given in Table 1.
The palladium atom is in the center of an approximately
square-planar arrangement formed by coordinated chlo-
rine, phosphorus and sulfur atoms. The Pd-Cl distances of
2.3088(11) A for Pd1-Cl1 and 2.3893(9) A for Pd1-Cl2 are
in harmony with the greater trans influence of P- versus S-
atom. This is consistent with previous observations [9] on
the relationship between the length of Pd-Cl bonds and the
trans influence of P and S atoms that are in trans position
to the Cl-atoms.
1. The palladium atom is in the center of the symmetry
and it displays a square-planar stereochemistry with a trans
configuration. Acting in a monodentate fashion, the ligand
is only bonded through the phosphorus atom leaving the
sulfur site non-bonded. By comparison, the Pd-Cl distance
˚
of 2.3017(11) A in compound II is shorter than both Pd-Cl
bonds in compound I. This is also in agreement with the
trans influence of Cl-atom which is weaker than P- or S-
atom.
˚
˚
3 Experimental Section
3.1 General Comments
Suitable crystals of compound II were grown from ben-
zene / diethyl ether solvent mixture. X-ray analysis of a 0.38
ϫ 0.30 ϫ 0.26 mm crystal gave the structure shown in Fig.
3. Selected bond lengths and bond angles are given in Table
All the reactions were carried out under dry nitrogen. Solvents were
purified and dried by standard methods. All chemicals used were
of reagent grade. [PdCl2(PhCN)2] was prepared as previously desc-
1434
Z. Anorg. Allg. Chem. 2002, 628, 1433Ϫ1436

Palladium(II) Complexes with the Mixed-Donor Ligand CH3S-(CH2)3-PPh2
time, solution changed color from red-brown to bright yellow, and
a yellow precipitate was formed. Solvent was removed under redu-
ced pressure till a volume of about 25 ml. The yellow precipitate
was collected, recrystallized from dichloromethane/pet. ether and
dried under vacuum at 50 °C. Yield 88 %. M.p. 204 °C(dec.). Calc.
For [C16H19Cl2PSPd] (451.67): C, 42.55; H, 4.24; S, 7.10. Found:
C, 42.28; H, 4.18; S, 6.89 %.
1H NMR (300 MHz, CDCl3): 7.90 Ϫ 7.51 (m,10H, Haromatic), 2.91 (m, 2H,
SCH2-), 2.61 (s, 3H, SCH3), 2.42 (m, 2H, -CH2-), 2.18 ppm (m, 2H, PCH2-).
Synthesis of [Dichlorobis(1-(methylthio)-3-
(diphenylphosphino)propane]palladium(II) (II)
A sample of the ligand (0.82 g, 3 mmol) was added to a filtered
solution of [PdCl2(PhCN)2] (0.59 g, 1.5 mmol) in benzene (50 ml).
The mixture was refluxed for 2 h. During that time, solution chan-
ged color from red-brown to bright yellow. The clear yellow solu-
tion was allowed to cool to room temperature. Solvent was remo-
ved under reduced pressure till a solution volume of about 25 ml.
Upon addition of diethyl ether an orange-yellow precipitate was
formed. The product was collected, recrystallized from benzene/
diethyl ether washed with diethyl ether and dried in vacuum at
50 °C. Yield 65 %. M.p. 145 °C. Calc. for [C32H38Cl2P2S2Pd]
(726.04): C, 52.94; H, 5.28; S, 8.83. Found: C, 52.72; H, 5.15; S,
8.19 %.
Fig. 3 ORTEP plot of the molecular structure of compound II.
Thermal ellipsoids are drawn at the 30% probability level.
ribed [13]. 1-(methylthio)-3-chloropropane was prepared from 1-
(methylthio)-3-propanol following literature procedure [14]. The IR
spectra were recorded , as KBr discs, on Nicolet Impact-400 FT-
IR spectrometer. The NMR spectra were recorded on a Bruker
DPX 300 MHz spectrometer using TMS as internal reference. Mel-
ting points were determined with Philip-Harris melting point appa-
ratus and are uncorrected. Conductivity measurements were carr-
ied out for 1.0 ϫ 10Ϫ3 M solution at 25 °C.
1H NMR (300 MHz, C6D6): 7.82 Ϫ 7.00 (m, 20H, Haromatic ), 2.57 (m, 4H,
PCH2- ), 2.25 (t, 4H, SCH2-), 1.84 (m, 4H, -CH2-), 1.66 ppm(s, 6H, -SCH3).
3.4 Reaction of compound I with S-P3
To a suspension of [PdCl2(S-P3)] (0.4 g, 1.0 mmol) in benzene
(20 ml) was added a solution of S-P3 (0.30 g, 1.1 mmol) in benzene
3.2 Syntheses
Table 2 Crystallographic data parameters for data collection and
refinement for [PdCl2(S-P3)] (I) and [PdCl2(S-P3)2] (II).
3.2.1 Synthesis of 1-(methylthio)-3-
(diphenylphosphino)propane (S-P3)
Entry
I·CH2Cl2
II
To a freshly prepared solution of sodium diphenylphosphide
(0.1 mol) in liquid ammonia (300 ml), a sample of 1-(methylthio)-
3-chloropropane (12.5 g, 0.1 mol) was added dropwise until the red
orange color of the solution was discharged (ϳ 1h). The ammonia
was allowed to evaporate over a period of 16 h. Residue was cau-
tiously hydrolyzed with 500 ml of pre-cooled distilled water. The
oily residue was extracted with dichloromethane (3 ϫ 30 ml). The
dichloromethane solution was dried with anhydrous sodium sulfate
(50 g). Solvent was removed under reduced pressure and the residue
was vacuum distilled. The product was collected at 230 °C and
50 mmHg. Yield 60 %.
Chemical formula
Formula weight
T /K
C17H21Cl4PSPd
536.57
193(3)
monoclinic
P21/n
8.589(3)
15.051(3)
17.100(3)
102.91(2)
2154.7(9)
4
C32H38Cl2P2S2Pd
725.98
193(2)
monoclinic
P21/n
9.993(5)
8.613(4)
18.721(5)
90.18(3)
1611.3(12)
2
Crystal system
Space group
˚
a /A
˚
b /A
˚
c /A
β /°
3
˚
V /A
Z
Dcalc. /(g.cmϪ3
)
1.654
1.496
Absorption coefficient/
1.526
0.992
1H NMR (300 MHz, CDCl3): δ: 7.41 Ϫ 7.26 (m, 10H, Haromatic), 2.55 (t, 2H,
mmϪ1
SCH2-), 2.12 (m, 2H, PCH2-), 2.01 (s, 3H, -SCH3), 1.72 (m, 2H, -CH2-). 13
C
Crystal dimensions /mm
θ range /°
Scan mode
0.40 ϫ 038 ϫ 0.35
2.71 Ϫ 25.25
ω/2θ
0.38 ϫ 0.30 ϫ 0.26
2.60 Ϫ 25.25
ω/2θ
1
NMR (75 MHz, CDCl3): δ: (Caromatic) 128.32 (d, JC-P 6.6 Hz, C1, 2C),
132.47 (d, JC-P 3.1 Hz, C2, 4C), 132.69 (s, C3, 4C), 128.46 (s, C4, 2C); δ:
2
1
2
(Caliphatic) 25.10 (d, JC-P 17.4 Hz, C1, 1C), 35.27 (d, JC-P 14.3 Hz, C2, 1C),
Number of data collected 4158
2994
26.81 (d, JC-P 12.1 Hz, C3, 1C) 15.14 (s, C4, 1C). IR (KBr, cmϪ1): ν(P-
3
Number of unique data
Number of data refined
Number of observed
reflections
3888 [Rint ϭ 0.0365]
3888
[I Ͼ 2σ(I)] 3422
2903 [Rint ϭ 0.0261]
2903
[I Ͼ 2σ(I)] 2462
phenyl) 1434 (s), ν(S-CH3) 1310 (m).
Number of parameters
217
0.0309
0.0773
0.603 and Ϫ0.477
178
0.0378
0.0986
0.788 and Ϫ0.426
3.2.2 Synthesis of [Dichloro(1-(methylthio)-3-
(diphenylphosphino)propane]palladium(II) (I)
Ra
wR2b (all data)
Residual density
A sample of the ligand (0.41 g, 1.5 mmol) was added to a filtered
solution of [PdCl2(PhCN)2] (0.59 g, 1.5 mmol) in benzene (50 ml).
The mixture was stirred at room temperature for 2 h. During that
a) R ϭ GʈFo ͉Ϫ͉Fc ʈ.
2
b) wR2 ϭ {Σ[w(Fo Ϫ Fc2)2] / Σ[w(Fo2)2] }0..5
Z. Anorg. Allg. Chem. 2002, 628, 1433Ϫ1436
1435

E. M. Al-Shami, A. S. Abu-Surrah, M. Klinga, H. A. Hodali
(20 ml). The mixture was stirred at room temperature for 1h. Du-
ring that time, the yellow solid slowly disappeared forming a clear
yellow solution. The solution was filtered and the volume of filtrate
was reduced to about 15 ml under reduced pressure. Upon addition
of diethyl ether, an orange-yellow precipitate was formed. The pro-
duct was collected, washed with diethyl ether and dried in vacuum
Acknowledgement. Financial support from the Deanship of Scien-
tific Research, University of Jordan is greatly acknowledged.
References
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1
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3.5 X-ray crystal structure determination for I and II
The crystal data of both I and II were collected on a Rigaku AFC-
7S single crystal diffractometer at 193(2) K using graphic mono-
˚
chromatized Mo-Kα radiation (0.71073 A). The intensities were
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Z. Anorg. Allg. Chem. 2002, 628, 1433Ϫ1436