Cyclopentadienyl ruthenium alkynyldithiocarboxylate complexes

Article abstract of DOI:10.1016/j.jorganchem.2005.12.057

Treatment of the ruthenium chloride, CpRu(PPh₃)₂Cl, with the alkynyldithiocarboxylate anions, RCCCS2-, in refluxing THF affords the chelate complexes CpRu(PPh₃)(κ²S,S-S ₂CCCR) (1) (R = Bu^t (a), Buⁿ (b), Ph (c), SiMe₃ (d)) in high yield. The room temperature reaction of the solvated species, [CpRu(PPh₃)₂(NCPh)]⁺, with the alkynyldithiocarboxylate anions, RCCCS2-, produces the chelate complexes 1 and the mono-coordinated complexes CpRu(PPh₃)₂(κS- S₂CCCR) (2). Complexes 2 are converted to 1 in solution so that they were characterized spectroscopically.

Full text of DOI:10.1016/j.jorganchem.2005.12.057

Journal of Organometallic Chemistry 691 (2006) 2055–2059
www.elsevier.com/locate/jorganchem
Note
Cyclopentadienyl ruthenium alkynyldithiocarboxylate complexes
a,
b
b
Mohammad El-khateeb *, Helmar Go¨rls , Wolfgang Weigand
a
Chemistry Department, Jordan University of Science and Technology, Irbid 22110, Jordan
Institut fu¨r Anorganische Chemie, Friedrich-Schiller-Universta¨t Jena, August-Bebel Strasse 2, Jena 07743, Germany
b
Received 4 December 2005; received in revised form 29 December 2005; accepted 29 December 2005
Available online 21 February 2006
Abstract
Treatment of the ruthenium chloride, CpRu(PPh3)2Cl, with the alkynyldithiocarboxylate anions, RCBCCSꢀ, in refluxing THF
2
affords the chelate complexes CpRu(PPh3)(j2S,S-S2CC„CR) (1) (R = But (a), Bun (b), Ph (c),SiMe3 (d)) in high yield. The room tem-
perature reaction of the solvated species, [CpRu(PPh3)2(NCPh)]+, with the alkynyldithiocarboxylate anions, RCBCCSꢀ, produces the
2
chelate complexes 1 and the mono-coordinated complexes CpRu(PPh3)2(jS-S2CC„CR) (2). Complexes 2 are converted to 1 in solution
so that they were characterized spectroscopically.
ꢀ 2006 Elsevier B.V. All rights reserved.
Keywords: Ruthenium; Dithiocarboxylate; Alkynes; Structure; Chelates; Sulfur; Triphenylphosphine; Carbon disulfide; Complexes
1. Introduction
These include Cp0Mo(CO)2(j2S,S-S2CC„CR) (Cp0 =
C5H5,C5Me5) [24], CpRu(PPh3)(j2S,S-S2CC„CPh) [25]
Dithiocarboxylato complexes of the transition metals
have been known for long time [1,2]. However, they have
been much less investigated compared to complexes of
other dithioacid ligands such as xanthates ðROCSꢀ2 Þ, thiox-
anthate ðRSCSꢀÞ and dithiocarbamates ðR2NCSꢀÞ [3–16].
and
CpFe(L)(j2S,S-S2CC„CR)
(L = PPh3,dppe-P,
dppm-P) [26]. All of these complexes have been made by
CS2 insertion into the metal–carbon bond of the corre-
sponding alkynyl-complexes. The complex Cp*Ru(PPh3)-
(j2S,S-S CC„CBut) (Cp = C Me ) is prepared by the
*
2
5
5
2
2
The dithiocarboxylate ligands were usually prepared by
the reaction of Grignard reagents or lithium aryls with
CS2 [1,2,17,18]. More recently, it was reported that the
addition of the alkynyl anions, RC„Cꢀ to CS2 at low tem-
perature is a convenient way to generate the alkynyldithio-
carboxylate ligands [19,20]. These ligands were used in the
preparation of several organic molecules such as dithioest-
ers [21] and 1,2-dithiole-3-thiones [22]. In organometallic
chemistry, these ligands were used in the preparation of
the Ru-complexes Ru(H)(CO)(PPh3)2(j2S,S-S2CC„CR)
(R = But,Ph,Mes) by direct interaction of the ligands with
Ru(H)(Cl)(PPh3)3(CO) [23].
interaction of CS2 with the carbene complex Cp Ru-
*
(PPh3)Cl(@C@CHBut) in the presence of a strong base
[27].
The insertion of CS2 into the Ru–C bond of
CpRu(PPh3)2C„CPh is quite difficult. It took heating for
four days in benzene for this insertion to give 56% yield
of CpRu(PPh3)(j2S,S-S2CC„CPh). The complex CpRu-
(PPh3)2Cl has a weak Ru–Cl bond, therefore, the Cl atom
in this molecule is labile and easily substituted especially in
polar solvents. Due to this fact, there should be an easier
route to synthesize CpRu(PPh3)-complexes containing
dithiocarboxylato ligands by reaction of CpRu(PPh3)2Cl
with dithiocarboxylato ligands. Our interest in the
reactions of CpRu(PPh3)2Cl with sulfur containing ligands
[28], and the availability of the anions, RCBCCSꢀ2 ,
prompted us to carry a study of these anions with
CpRu(PPh3)2Cl. In this report we describe the preparation
Several organotransition metal complexes of alkynyldi-
thiocarboxylate ligands are reported in the literature.
*
Corresponding author. Tel.: +962 2 7201000; fax: +962 2 7095014.
E-mail address: kateeb@just.edu.jo (M. El-khateeb).
0022-328X/$ - see front matter ꢀ 2006 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2005.12.057

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M. El-khateeb et al. / Journal of Organometallic Chemistry 691 (2006) 2055–2059
and characterization of some alkynyldithiocarboxylate
ruthenium complexes.
gested similar structures and negligible effects for the
R-group at the end of the molecules.
The molecular structure of CpRu(PPh3)(j2S,S-
S2CC„CBut) (1a) was determined and is shown in Fig. 1.
Selected bond distances and bond angles of 1a are shown
in Table 1. The structure definitively proves that both
S-atoms are bonded to the Ru-center with Ru–S distances
2. Results and discussion
The reaction of cyclopentadienylbis(triphenylphos-
phine)ruthenium chloride with various alkynyldithiocarb-
oxylate anions in refluxing THF affords the complexes
CpRu(PPh3)(j2S,S-S2CC„CR) (1) (R = But (a), Bun (b),
Ph (c), SiMe3 (d)) in high yield (Scheme 1). The anionic
ligands were prepared by the reaction of the alkynyl anions
RC„CLi with CS2 at low temperature. Complexes 1 are
new, but 1c is known [25]. Complexes 1 are dark red solids,
stable both as solids and in solutions. They are soluble in
most common organic solvents and in some cases (1c, 1d)
are soluble in hydrocarbon solvents.
˚
of 2.3627(5) and 2.3667(5) A. These distances are similar to
those of CpRu(PPh3)(j2S,S-S2CC„CPh) (2.336(3),
˚
2.353(4) A) [25] and also similar to those found for
2
t
Cp*Ru(PPh3)(j S,S-S2CC„CBu ) (2.37(1), 2.350(9) A)
[27]. The Cp-ligand is bonded to the Ru atom in g5-fashion
with Ru–C bond distances ranging from 2.197(2) to
˚
˚
˚
2.210(2) A. The Ru–P bond distance of 2.3004(5) A is similar
to those of complexes containing the CpRu(PPh3) moiety
[10–13,29,30].
Complexes 1 have been characterized by spectroscopic
methods (1H, 31P NMR, IR), elemental analysis and X-
ray diffraction for compound 1a. The spectroscopic results
are in agreement with the suggested structures. The pres-
ence of the alkynyldithiocarboxylate ligands is shown in
the IR spectra of complexes 1 by the mC„C bands between
2120 and 2197 cmꢀ1. This frequency is similar to those
reported for analogous complexes, e.g., Cp*Ru(PPh3)-
(j2S,S-S2CC„CBut) (2195 cmꢀ1) [27] and CpRu(PPh3)-
(j2S,S-S2CC„CPh) (2170 cmꢀ1) [25]. The 1H NMR
spectra of 1 exhibited Cp-protons in the range 4.50–
4.56 ppm. The peaks for the R-groups and the PPh3 ligand
are also present in the spectra with the correct splitting and
intensities. The 31P NMR spectra of these complexes show
a singlet in the range 56.77–57.14 ppm. These results sug-
Complexes 1 are believed to be obtained from the corre-
sponding bis(triphenylphosphine) complexes, 2 by loss of
PPh3 ligand (Scheme 1). In order to prove this suggestion,
the complexes CpRu(PPh3)2(jS-S2CC„CR) (2) were pre-
pared from the reaction of [CpRu(PPh3)2(NCPh)]+ with
RCBCCSꢀ2 . However, this reaction always gives a mixture
of 1 and 2. Our attempts to isolate pure samples of 2 failed,
they spontaneously converted to 1 in solution. This is not a
surprising result on the basis that some complexes contain-
ing the CpRu(PPh3)2-moiety have a high tendency to loss
PPh3 ligand in solution [31]. Also, the ability of the dithio-
carboxylate ligand to act as a chelate ligand is high, even it
is higher than that of the bis(phosphine) ligands [26]. Com-
plexes 2 have been characterized by 1H and 31P NMR spec-
troscopy. However, their spectra always display signals for
S
Ru
Ru
+
+
PPh3
S
Ph3P
LiS
Ph3P
Cl
S
R
PPh3
1
NaPF6
PhCN
Solvent
r.t.
R
+
S
S
+
1
Ru
PPh3
Ru
+
LiS
Ph3P
NCPh
Ph3P
S
PPh3
2
R
R
R= But (a), Bun (b), Ph (c), SiMe3 (d)
Scheme 1.

M. El-khateeb et al. / Journal of Organometallic Chemistry 691 (2006) 2055–2059
2057
C10
C11
C12
C9
C23
C22
C8
C24
C21
C19
Ru
C20
S1
C14
C1
C15
C17
C13
C26
S2
C25
C2
C16
C30
C18
C27
C3
C4
C28
C29
C5
C6
C7
Fig. 1. ORTEP drawing of CpRu(PPh3)(j2S,S-S2CC„CBut), 1a.
Table 1
Selected bond length (A) and angles (ꢁ) of CpRu(PPh3)(j2S,S-
using a Varian Avance 200 or 400 MHz spectrometer.
Chemical shifts are quoted in ppm downfield of TMS
and referenced using the chemical shifts of residual solvent
resonances. Elemental analyses were performed by the
Institute of Organic and Macromolecular Chemistry,
FSU-Jena. Melting points were recorded on a polariza-
tion-microscope (Axiolab) connected to a heating unit
(THMS-600) using the software Linkam LNP and CI 93.
˚
S2CC„CBut) (1a)
Ru–S1
Ru–S2
Ru–C8
Ru–C9
Ru–C10
Ru–C11
Ru–P1
S1–C1
S2–C1
C1–C2
C2–C3
C3–C4
2.3627(5)
2.3667(5)
2.197(2)
2.203(2)
2.202(2)
2.210(2)
2.3005(5)
1.691(2)
1.691(2)
1.418(3)
1.200(3)
1.478(3)
P1–Ru–S1
P1–Ru–S2
S1–Ru–S2
S1–C1–C2
C1–S1–Ru
C1–S2–Ru
C1–C2–C3
C2–C3–C4
94.726(19)
89.930(18)
71.520(19)
109.62(11)
89.43(7)
89.28(7)
178.4(2)
178.4(2)
3.1. General procedure for the preparation of
CpRu(PPh3)(j2S,S-S2CCCR) (1)
A 100-mL two-neck flask fitted with a reflux condenser
was charged with CpRu(PPh3)2Cl (0.50 g, 0.68 mmol) and
50.0 mL of THF. A 10.0 mL THF solution of the
alkynyldithiocarboxylate anion (0.55 mmol) was added in
one portion. The resulting orange solution was refluxed
for 2 h at which the color becomes dark red. The solvent
was removed under vacuum and the resulting red solid
was redissolved in a minimum amount of THF and was
introduced to a silica gel column made up in hexane. Elu-
tion with THF:hexane (1:1 v:v ratio) gave a red band which
was collected, dried and was recrystallized from THF/
hexane.
1 in some percent depending on how long they stayed in
solution. Their spectra show the signals for the Cp-ligands
in the range 4.40–4.50 ppm and the corresponding 31P
NMR spectra show singlets for the phosphine ligand in
the range of 47.10–47.14 ppm.
3. Experimental
All manipulations were performed under an inert atmo-
sphere of argon, using standard Schlenk line techniques.
Tetrahydrofuran (THF) and hexane were dried and freshly
distilled over sodium/benzophenone under argon prior to
use. The reagents: CpRu(PPh3)2Cl [32], [CpRu(PPh3)2-
(NCPh)]PF6 [33] and alkynyldithiocarboxylate anions [21]
were prepared as previously reported. Infrared spectra
were recorded on a Perkin–Elmer AC 2000 FT-IR spec-
3.1.1. CpRu(PPh3)(j2S,S-S2CC„CBut) (1a)
Dark red crystals (90%). m.p.: 222–223 ꢁC. IR (KBr,
1
cmꢀ1): mC„C 2194 (s). H NMR (CDCl3): d 1.16 (s, 9H,
CMe3); 4.50 (s, 5H, C5H5); 7.30 (m, 9H, PPh3); 7.41 (m,
6H, PPh3). 31P NMR (CDCl3): d 57.07. Anal. Calc. for
C30H29PRuS2: C, 61.52; H, 4.99; S, 10.95. Found: C,
61.31; H, 4.90; S, 10.96%.
1
trometer in KBr. H and 31P NMR spectra were recorded

2058
M. El-khateeb et al. / Journal of Organometallic Chemistry 691 (2006) 2055–2059
3.1.2. CpRu(PPh3)(j2S,S-S2CC„CBun) (1b)
Table 2
Selected crystal data and refinement parameters for CpRu(PPh3)(j2S,S-
S2CC„CBut) (1a)
Dark red crystals (87%). m.p.: 107–108 ꢁC. IR (KBr,
1
cmꢀ1): mC„C 2197 (s). H NMR (CDCl3): d 0.86 (t, 3H,
Empirical formula
C30H29PRuS2
CH3); 1.25 (m, 2H, CH2); 1.53 (m, 2H, CH2); 3.45 (t, 2H,
CH2); 4.51 (s, 5H, C5H5); 7.32 (m, 9H, PPh3); 7.44 (m,
6H, PPh3). 31P NMR (CDCl3): d 57.10. Anal. Calc. for
C30H29PRuS2: C, 61.52; H, 4.99; S, 10.95. Found: C,
59.02; H, 5.05; S, 14.33%.
Crystal size (mm)
Crystal system
Space group
Volume (A )
Z
0.10 · 0.10 · 0.08
Triclinic
ꢀ
P1
3
˚
1329.15(7)
2
Unit cell dimensions
3.1.3. CpRu(PPh3)(j2S,S-S2CC„CPh) (1c)
˚
a (A)
11.2606(3)
11.2890(4)
11.7437(3)
63.936(2)
84.948(2)
82.641(2)
˚
b (A)
Dark red crystals (85%). m.p.: 118–120 ꢁC. IR (KBr,
˚
c (A)
1
cmꢀ1): mC„C 2174 (s). H NMR (CDCl3): d 4.56 (s, 5H,
a (ꢁ)
b (ꢁ)
c (ꢁ)
C5H5); 7.30 (m, 9H, PPh3); 7.40 (m, 6H, PPh3); 7.70 (m,
5H, Ph). 31P NMR (CDCl3): d 57.14. Anal. Calc. for
C33H25PRuS2: C, 63.45; H, 4.16; S, 10.59. Found: C,
62.98; H, 4.37; S, 10.78%.
Index range
Formula weight
Radiation type
Density (Mg/m3)
ꢀ14 6 h 6 14, ꢀ12 6 k 6 14, ꢀ14 6 l 6 15
585.69
Mo Ka
1.463
3.1.4. CpRu(PPh3)(j2S,S-S2CC„CSiMe3) (1d)
l (mmꢀ1
k (A)
)
0.824
˚
Dark red crystals (82%). m.p.: 130–131 ꢁC. IR (KBr,
0.71069
1.93–27.43
0.0278
0.0684
2
1
cmꢀ1): mC„C 2120 (s). H NMR (CDCl3): d 0.12 (s, 9H,
h (ꢁ)
R[F2 > 2r(F2)]
SiMe3); 4.53 (s, 5H, C5H5); 7.31 (m, 9H, PPh3); 7.40 (m,
6H, PPh3). 31P NMR (CDCl3): d 56.77. Anal. Calc. for
C29H29PRuS2Si: C, 57.88; H, 4.68; S, 10.66. Found: C,
57.98; H, 5.10; S, 10.66%.
xR(F2)a
a
x ¼ 1=½r2ðF o2Þ þ ð0:0598PÞ ꢁ where P ¼ ðF o2 þ 2F 2cÞ=3.
3.3. Crystallographic analysis of CpRu(PPh3)(j2S,S-
S2CCCBut) (1a)
3.2. General procedure for the preparation of
CpRu(PPh3)2(j1S-S2CCCR) (2)
Single crystals suitable for the X-ray study were
obtained by recrystallization of 1a from THF/hexane mix-
ture. A crystal of size 0.10 · 0.10 · 0.08 mm was used for
data collection. The crystallographic data are shown in
Table 2. The geometric and intensity data were collected
at 173(2) K on a KappaCCD diffractometer. There was
8948 total reflections with 5889 independent reflections
(Rint = 0.017). The structures were solved by direct meth-
ods using SHELXS [34] and refined by full-matrix least-
squares on F 2o using SHELX-97 [35]. All non-hydrogen atoms
were refined anisotropically. The crystal data and structure
refinement details are shown in Table 2.
A
100-mL two-neck flask was charged with
[CpRu(PPh3)2(NCPh)]PF6 (0.50 g, 0.53 mmol) and
50.0 mL of THF. A 10.0 mL THF solution of the alkynyldi-
thiocarboxylate anion (0.55 mmol) was added in one por-
tion. The resulting yellow solution was stirred overnight.
TLC (THF/hexane 1:1 v:v ratio) showed two products are
formed. The solvent was removed under vacuum and the
resulting red solid was redissolved in a minimum amount
of THF and was introduced to a silica gel column made up
in hexane. Elution with THF:hexane (1:1 v:v) ratio gave a
red band which was collected and identified as 1 followed
by another red band which was also collected and dried
and was identified as CpRu(PPh3)2(j1S-S2CC„CR).
4. Supplementary materials
3.2.1. CpRu(PPh3)2(j1S-S2CC„CBut) (2a)
1H NMR (CDCl3): d 4.49 (s, 5H, C5H5). 31P NMR
(CDCl3): d 47.14.
Crystallographic data have been deposited with the
Cambridge Crystallographic Data Centre, (deposition
No. CCDC No. 289730) for compound 1a. Copies of
this information can be obtained free of charge from
The Director, CCDC, 12 Union Road, Cambridge,
CB2 1EZ, UK, fax: +44 1233 336 033, e-mail:
deposit@ccdc.cam.ac.uk or www: http://www.ccdc.
cam.ac.uk.
3.2.2. CpRu(PPh3)2(j1S-S2CC„CBun) (2b)
1H NMR (CDCl3): d 4.40 (s, 5H, C5H5). 31P NMR
(CDCl3): d 47.10.
3.2.3. CpRu(PPh3)2(j1S-S2CC„CPh) (2c)
1H NMR (CDCl3): 4.41 (s, 5H, C5H5). 31P NMR
(CDCl3): d 47.11.
Acknowledgments
3.2.4. CpRu(PPh3)2(j1S-S2CC„CSiMe3) (2d)
1H NMR (CDCl3): 4.40 (s, 5H, C5H5). 31P NMR
(CDCl3): d 47.10.
M.E. thanks Alexander von Humbodt Stiftung for
scholarship and Jordan University of Science and Technol-
ogy for financial support.

M. El-khateeb et al. / Journal of Organometallic Chemistry 691 (2006) 2055–2059
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