Ruthenium(II) carbonyl complexes containing tertiary phosphine chalcogenide ligands of the type Ph3PX; X=O, S, Se

Article abstract of DOI:10.1016/j.poly.2004.03.016

The reactions of polymeric complex [Ru(CO)₂Cl₂] _n with triphenyl phosphine chalcogenide ligands Ph₃PX; X=O(a), S(b), Se(c) in 1:1 (Ru:L ratio) molar ratio gives five-coordinate complexes of the type [Ru(CO)

Full text of DOI:10.1016/j.poly.2004.03.016

Polyhedron 23 (2004) 1657–1661
www.elsevier.com/locate/poly
Ruthenium(II) carbonyl complexes containing tertiary
phosphine chalcogenide ligands of the type Ph3PX; X ¼ O, S, Se
Pratap Chutia , Nandini Kumari , Manab Sharma , J. Derek Woollins ,
a
a
a
b
b
Alexandra M. Z. Slawin , Dipak Kumar Dutta
a,
*
a
Material Science Division, Regional Research Laboratory (CSIR), Jorhat 785006, Assam, India
b
Department of Chemistry, University of St. Andrews, St. Andrews KY 16 9ST, UK
Received 18 February 2004; accepted 29 March 2004
Available online 23 April 2004
Abstract
The reactions of polymeric complex [Ru(CO)2Cl2]n with triphenyl phosphine chalcogenide ligands Ph3PX; X ¼ O(a), S(b), Se(c) in
1:1 (Ru:L ratio) molar ratio gives five-coordinate complexes of the type [Ru(CO)2Cl2(Ph3PX)](1a–c) while 1:2 (Ru:2L ratio) molar
ratio produces six-coordinate [Ru(CO)2Cl2(Ph3PX)2](2a–c) complexes. The complexes 1a–c and 2a–c exhibit two equally intense m(CO)
bands in the range 2059–1989 and 2050–1980 cmꢀ1, respectively, indicating cis-disposition of the two terminal carbonyl groups. The
values of m(CO) frequencies irrespective of the complexes, in general, follow the order: Ph3PO > Ph3PS > Ph3PSe which may be ascribed
in terms of ‘‘Soft–Hard’’ (Ru(II)–O) and ‘‘Soft–Soft’’ (Ru(II)–S/Se) interactions. The m(PX) bands of the complexes observed in the
range 1173–538 cmꢀ1 are 19–41 cmꢀ1 lower than those of the corresponding free ligands indicating the formation of Ru–X bonds. The
molecular structure of the complex [Ru(CO)2Cl2(Ph3PS)2] was determined by single X-ray crystallography. The crystal is monoclinic,
ꢀ
ꢀ
ꢀ
space group Cc; a ¼ 11:4990 A, b ¼ 17:3966 A, c ¼ 18:4788 A; a ¼ 90°, b ¼ 98:160°, c ¼ 90°. In the molecule, the Ru(II) atom occupies
the center of a slightly distorted octahedral geometry which consists of two trans-S atoms of two Ph3PS ligands, two cis-CO groups and
two cis-chlorides. The complexes have also been characterized by elemental analysis, 1H, 13C and 31P NMR spectroscopy.
Ó 2004 Elsevier Ltd. All rights reserved.
Keywords: Ruthenium(II) carbonyl complexes; Tertiary phosphine chalcogenides; ‘‘Soft–Hard’’ and ‘‘Soft–Soft’’ interactions; X-ray crystal
structure; Octahedral structure
1. Introduction
tention although the chemistry of such ligands is poten-
tially important and well established. There are reports of
some complexes with platinum metals [8–15], but to the
best of our knowledge, only a few reports [16–21] are
there on ruthenium(II) complexes. This prompted us to
synthesize, characterize and to study coordination chem-
istry of ruthenium(II) carbonyl complexes with these
chalcogen donors ligands.
In the present communication, we report the synthesis,
spectroscopic characterization and structural investiga-
tion of some ruthenium(II) carbonyl complexes derived
from the reaction of [Ru(CO)2Cl2]n with Ph3PX; X ¼ O,
S, Se and the effect of ‘‘Soft–Hard’’ and ‘‘Soft–Soft’’ na-
ture of the chalcogenide ligands on m(CO) frequency is
discussed. In order to the determine detailed geometry, an
X-ray diffraction study was undertaken for one of the
sulfide complexes.
The chemistry of rhodium and ruthenium metal
complexes of unsymmetrical chelating phosphines func-
tionalized with chalcogen donors like Ph2P(CH2)n
P(X)Ph2(n ¼ 1–4, X ¼ O, S, Se), Ph2PC6H4COOMe,
Ph2P(CH2)nOR (R ¼ CH3, C2H5) has gained much im-
portance because of their structural novelty, reactivity
and catalytic applications [1–7]. In contrast, monoden-
tate tertiary phosphines functionalized with chalcogen
donors such as Ph3PX (X ¼ O, S, Se) received less at-
* Corresponding author. Tel.: +91-376-237-0081/0147; fax: +91-376-
237-0011.
E-mail addresses: dipakkrdutta@yahoo.com, dipdutta49@ya-
hoo.com (D. Kumar Dutta).
0277-5387/$ - see front matter Ó 2004 Elsevier Ltd. All rights reserved.
doi:10.1016/j.poly.2004.03.016

1658
P. Chutia et al. / Polyhedron 23 (2004) 1657–1661
2. Experimental
2.1. General methods
which was washed with diethyl ether and finally
recrystallized from dichloromethane solution.
Analytical data and physical properties of the com-
plexes are shown in Table 1.
All the solvents used were distilled under nitrogen
prior to use. Carbon and hydrogen analyses were done
on a Perkin–Elmer 2400 elemental analyzer. Chloride
analyses were performed by standard analytical method
[22]. FT-IR spectra of range 4000–400 and 400–200 cmꢀ1
were recorded using Perkin–Elmer 2000 and Perkin–El-
mer 883 spectrophotometer, respectively, in KBr disc.
NMR data were recorded on a Bruker DPX 300 MHz
2.3. X-ray crystallography
A crystal of the complex 2b suitable for X-ray crys-
tallographic analysis was developed from a CH2Cl2-
hexane solution. Data collection was performed using a
Bruker SMART diffractometer, full sphere of data with
1
spectrometer and the H and 31P NMR chemical shifts
Table 2
Crystal data and structure refinement of the complex 2b
were quoted relative to SiMe4 and 85% H3PO4 as inter-
nal and external standard, respectively, using CDCl3 and
d6-acetone as solvent. Melting points were determined
with a BUCHI B-540 apparatus. RuCl3 ꢁ 3H2O was
purchased from M/s Arrora Matthey Ltd., Kolkata,
India. Analytically pure Ph3P and elemental sulfur, se-
lenium were purchased from M/S Aldrich, USA and used
without further purification. The ligands, Ph3PX, X ¼ O,
S, Se were prepared by the literature method [23–25]. The
starting complex [Ru(CO)2Cl2]n was prepared by passing
CO through a refluxing solution of RuCl3 ꢁ 3H2O in
ethanol for about 24 h [26–29].
Empirical formula
Formula weight
Temperature (K)
C38H30Cl2O2P2RuS2
816.65
293(2)
ꢀ
Wave length (A)
0.71073
monoclinic
Cc
Crystal system
Space group
ꢀ
a (A)
11.4990(11)
17.3966(16)
18.4788(17)
90
ꢀ
b (A)
ꢀ
c (A)
a (°)
b (°)
c (°)
Volume (A )
Z
98.160(2)
90
3659.1(6)
3
ꢀ
4
1.482
Dcalc (Mg/m3)
Absorption coefficient (mmꢀ1
F ð000Þ
2.2. Synthesis of metal complexes
)
0.809
1659
2.2.1. [Ru(CO)2Cl2(Ph3PX)] (1a–c), X ¼ O, S, Se
0.044 mmol of [Ru(CO)2Cl2]n was dissolved in 10 cm3
methanol and to this 0.044 mmol of corresponding li-
gands a–c in 10 cm3 dichloromethane was added. The
reaction mixture was stirred at room temperature for
about 2 h and the solvent was evaporated under vac-
uum. The solid compound so obtained was washed with
diethyl ether and recrystallized from dichloromethane
solution.
Crystal size (mm)
0.1 ꢂ 0.1 ꢂ 0.02
2.14–25.40
ꢀ13 6 h 6 12, ꢀ20 6 k 6 20,
ꢀ22 6 l 6 22
12 461
h Range for data collection (°)
Index ranges
Reflections collected
Independent reflections
Completeness to h ¼ 25:40°
Absorption correction
Maximum and minimum
transmission
6304 ðRint ¼ 0:1091Þ
99.7 %
MULTISCAN
1.00000 and 0.933609
Refinement method
full-matrix least-squares on F 2
6304/2/425
0.603
Data/restraints/parameters
Goodness-of-fit on F 2
Final R indices ½I > 2rðIÞꢃ
R indices (all data)
2.2.2. [Ru(CO)2Cl2(Ph3PX)2](2a–c), X ¼ O, S, Se
0.044 mmol of [Ru(CO)2Cl2]n was dissolved in
methanol (10 cm3) and to this 0.088 mmol of corre-
sponding ligands a–c in 10 cm3 dichloromethane was
added. The reaction mixture was stirred at room tem-
perature for about 2.5 h and the solvent was evaporated
under reduced pressure to generate a solid compound
RI ¼ 0:0475, wR2 ¼ 0:0957
RI ¼ 0:1495, wR2 ¼ 0:1447
0.11(6)
Absolute structure parameter
Extinction coefficient
Largest differential peak and
0.00034(14)
0.333 and )0.306
ꢀ3
ꢀ
hole (e A
)
Table 1
Analytical data and physical properties of the complexes
Complexes
Yield (%)
Colour
Melting point (°C)
Found (Calc.) (%)
C
H
Cl
1a
1b
1c
2a
2b
2c
92
96
95
89
90
87
light green
red-brown
dark-brown
light green
red-brown
dark-brown
182 (decomposed)
187
47.44(47.40)
45.91(45.94)
42.12(42.15)
58.09(58.11)
55.83(55.84)
50.05(50.07)
2.93(2.96)
2.89(2.87)
2.60(2.63)
3.80(3.82)
3.66(3.67)
3.31(3.29)
14.00(14.02)
13.56(13.59)
12.50(12.47)
9.03(9.05)
173
185 (decomposed)
192
176
8.71(8.69)
7.82(7.80)

P. Chutia et al. / Polyhedron 23 (2004) 1657–1661
1659
0.3° slices, room temperature, Mo Ka radiation and
empirical absorption corrections. All non-hydrogen at-
oms were refined anisotropically with the hydrogen at-
oms being refined in idealized geometries. The structure
refinements were done by full matrix least square on F 2
using SHELXTL97 computer program [30]. The crystal
data and structure refinement for the complex are listed
in Table 2.
1173, 590, 538 cmꢀ1which are 27, 41, 20 cmꢀ1 lower
than their corresponding free ligands indicating the
formation of bonds Ru–O, Ru–S and Ru–Se, respec-
tively [9]. The cis-disposition of the two chlorides in the
complexes is corroborated by the presence of two
1
m(RuCl) bands in the range 246–330 cmꢀ1 [29]. The H
NMR spectra of the complexes show a set of multiplets
in the d7.26–7.85 ppm range assigned to the phenyl
groups of triphenyl chalcogenide ligands. No apprecia-
ble shift is observed between coordinated and free ligand
proton environment as the protons are remote from the
coordinating chalcogen atom. The 31P {H} NMR
spectra of the complexes 1a–c (Table 3) exhibit singlet
resonance at d 43.88, 48.24, 32.43 ppm, respectively,
while their corresponding free ligand values occur at d
30.37, 44.54, 36.53 ppm. Compared to the free ligands,
the phosphorus atoms of the complexes show a small
down field shift (3.70–13.51 ppm) because the phos-
phorus atoms are already attached with the chalcogen
donor in the ligands. 13C NMR data of the complexes
1a–c are given in Table 3. The principal interest is on the
carbonyl carbon and the 13C NMR values are found to
be a singlet at 182, 184, 186 ppm of the complexes 1a–c
respectively. Similar to the complex [RuCl2(PPh3)3] [33],
these 16-electron complexes are assumed to show no
steric barrier for H-coordination of a phenyl ring to
block the 6th coordination site and the probable struc-
ture of the complexes are shown in Fig 1(a), although we
could not develop suitable crystal for X-ray study.
Reaction of 1a–c with one molar equivalent of li-
gands a–c yields six-coordinate 18 electron species of the
type [Ru(CO)2Cl2(Ph3PX)2](2a–c) (Scheme 1); X ¼ O, S,
3. Results and discussion
Reaction of polymeric [Ru(CO)2Cl2]n with one molar
equivalent (Ru:L ¼ 1:1) of the ligands (a–c) affords five-
coordinate 16 electron species of the type [Ru(-
CO)2Cl2(Ph3PX)](1a–c) (Scheme 1) where X ¼ O, S, Se.
The IR spectra (Table 3) of the complexes show two
equally intense m(CO) bands in the range 1980–2060
cmꢀ1 attributing cis-disposition of the two terminal
carbonyl groups [31,32]. The positions of the m(CO)
bands lie in the sequence Ph3PO > Ph3PS > Ph3PSe. The
reason of variation in m(CO) frequency may be explained
in terms of ‘‘Soft–Hard’’ and ‘‘Soft–Soft’’ interactions
between the metal atom and the chalcogen donors. S
and Se donors being ‘‘Soft’’ in complexes 1b and 1c, they
interact strongly with ‘‘Soft’’ ruthenium(II), in contrast
to the ‘‘Hard’’ oxygen in the complex 1a. Because of the
‘‘Soft–Soft’’ interaction, the electron density increases
on the central metal atom which leads to donate more
dp-electrons to the antibonding pꢄ orbital of the CO
[7,32] and consequently reduces the C–O bond order,
which in turn lowers the m(CO) frequency. The m(PX)
(X ¼ O, S, Se) bands in the complexes 1a–c occur at
Scheme 1. Synthesis of complexes (1a–c and 2a–c).
Fig. 1. Proposed structures for complexes 1a–c (a) and 2a–c (b).
Table 3
IR (cmꢀ1) and NMR (ppm) data of the complexes
Complexes
IR
31Pb
1H
13C
CO
m(CO)
m(PXa) (X ¼ O, S, Se)
1173
m(RuCl)
C6H5
C6H5
1a
1b
1c
2a
2b
2c
2059, 1994
2054, 1991
2052, 1989
2050, 1985
2045, 1980
2043, 1981
330, 257
310, 246
312, 251
328, 280
314, 281
309, 283
43.88
48.24
32.43
43.87
48.21
32.46
7.31–7.85 m
7.36–7.75 m
7.26–7.76 m
7.27–7.87 m
7.34–7.81 m
7.34–7.75 m
182
184
186
183
182
184
128.83–133.81
128.83–132.72
128.86–133.15
128.81–133.64
128.82–132.72
128.85–133.12
590
538
1165
591
539
a Free Ph3PO, 1200 cmꢀ1; Ph3PS, 631cmꢀ1; Ph3PSe, 558 cmꢀ1
.
b Free Ph3PO, 30.37 ppm; Ph3PS, 44.54 ppm; Ph3PSe, 36.53 ppm.

1660
P. Chutia et al. / Polyhedron 23 (2004) 1657–1661
Table 4
Se. The complexes 2a–c can also be synthesized directly
by reacting [Ru(CO)2Cl2]n with ligands a–c in 1:2 molar
ratio. As in the complexes 1a–c, the position and nature
of m(CO) and m(RuCl) IR bands (Table 3) are in agree-
ment with the mutual cis-disposition of the terminal
carbonyl groups and the two chlorides. Similar to the
complexes 1a–c, the m(PX) (X ¼ O, S, Se) bands in
complexes 2a–c also show considerable lower values
(19–40 cmꢀ1) suggesting coordination via chalcogen
donor sites. The 31P {H } NMR spectra of 2a–c also
show one singlet resonance showing a small shift in the
range 3.67–13.50 ppm. The 13C NMR spectra (Table 3)
of the complexes show characteristics signals for car-
bonyl and phenyl carbon atoms. Thus on the basis of IR
and NMR data, Fig. 1(b) is the most probable structure
of the complexes 2a–c.
In order to confirm the structures and to determine the
detailed geometry, we tried to grow crystals of the com-
plexes. A good crystal suitable for X-ray structural de-
termination was obtained for the complex 2b. IR and
NMR data are well agreed with this molecular structure
of the complex. The arrangements and numbering of the
atoms in the crystal are shown in Fig. 2 and the important
bond lengths and bond angles are given in Table 4. In the
molecule, the ruthenium atom has a slightly distorted
octahedral coordination with two Ph3PS ligands occu-
pying two trans-octahedral sites via two sulfur atoms, two
cis CO groups and two cis-chlorides. This atomic ar-
rangement is sterically less hindered and is apparently
preferred because both the bonded sulfur atoms of the
ligands are trans to each other. The bond lengths Ru–Cl
ꢀ
Selected bond lengths (A) and bond angles (°) of the complex 2b
Bond lengths
Ru–C(37)
Ru–C(38)
Ru–S(2)
1.836(13)
1.865(14)
2.414(3)
2.426(3)
2.432(4)
2.449(3)
Ru–S(1)
Ru–Cl(1)
Ru–Cl(2)
Bond angles
C(37)–Ru–C(38)
C(37)–Ru–S(2)
C(38)– Ru–S(2)
C(37)– Ru–S(1)
C(38)–Ru–S(1)
S(2)–Ru–S(1)
93.2(5)
100.5(4)
91.2(3)
92.0(4)
99.2(3)
163.32(10)
177.7(4)
89.0(4)
C(37)–Ru–Cl(1)
C(38)–Ru–Cl(1)
S(2)–Ru–Cl(1)
S(1)–Ru–Cl(1)
C(37)–Ru–Cl(2)
C(38)–Ru–Cl(2)
S(2)–Ru–Cl(2)
S(1)–Ru–Cl(2)
Cl(1)–Ru–Cl(2)
80.17(11)
86.96(12)
86.5(4)
179.0(4)
87.92(11)
81.76(10)
91.26(13)
The large deviation from 180° for S(2)–Ru–S(1) is prob-
ably due to steric requirement to get a stable structure [36],
where the uncoordinated phenyl rings are oriented away
from the plane containing chlorides, CO groups and the
metal centre. The angles C(37)–Ru–C(38), C(37)–Ru–
S(2), C(38)–Ru–S(2), C(37)–Ru–S(1), C(38)–Ru–S(1),
C(38)–Ru–Cl(1), S(2)–Ru–Cl(1), S(1)–Ru–Cl(1), C(37)–
Ru–Cl(2), S(2)–Ru–Cl(2), S(1)–Ru–Cl(2) and Cl(1)–Ru–
Cl(2) exhibit different values in the range 80.17°–100.5°
with the deviation from 90° (Table 4). This indicates that
there may be significant inter and intra atomic interac-
tions amongst the bonding atoms and with the bulky
phenyl rings which cause such deviations.
ꢀ
ꢀ
‘‘2.432, 2.449 A’’, Ru–CO ‘‘1.836, 1.865 A’’ and Ru–S
ꢀ
‘‘2.414, 2.426 A’’ are closely similar to those observed
previously in [Ru(CO)2(BzIPPh2)Cl2] (Ru–Cl, ‘‘2.428,
6
ꢀ
ꢀ
2.430 A’’; Ru–CO, ‘‘1.858, 1.869A’’) [34] and [g -
MeC6H4PriRu{g3-(SPPh2)2CMe–C,S,S0}]PF6
(Ru–S,
‘‘2.421, 2.449 A’’) [35]. The basal Ru–Cl(2) and Ru–C(38)
ꢀ
ꢀ
bond lengths are 2.449 and 1.865 A while their corre-
sponding apical bonds Ru–Cl(1) and Ru–C(37) are little
4. Supplementary material
ꢀ
shorter (2.432 and 1.836 A, respectively). This shortening
of the apical bonds may be due to a steric effect [34]. The
bond angles for C(37)–Ru–Cl(1), C(38)–Ru–Cl(2) and
S(2)–Ru–S(1) are 177.7°, 179° and 163.32°, respectively.
Supplementary data are available from the CCDC, 12
Union Road, Cambridge CB2 1EZ, UK on request.
CCDC deposition number 230409. Copies of this in-
formation may be obtained free of charge from the
Director, CCDC, 12 Union Road Cambridge, CB2 1EZ,
UK (fax: +44-1223-336033; e-mail: deposit@ccdc.cam.
ac.uk or www: http://www.ccdc.cam.ac.uk).
Acknowledgements
The authors are grateful to Dr. P.G. Rao, Director,
Regional Research Laboratory (CSIR), Jorhat, India,
for his kind permission to publish the work. The authors
thank Dr. P.C. Borthakur, Head Material Science Di-
vision, RRL Jorhat, for his encouragement and support.
Fig. 2. Molecular structure of [Ru(CO)2Cl2(PPh3S)2] (2b).

P. Chutia et al. / Polyhedron 23 (2004) 1657–1661
1661
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The Department of Science and Technology (DST) New
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