Synthesis, crystal structures and NMR spectroscopic studies on ruthenium complexes with phosphanylacetal and phosphanylthioacetal ligands

Article abstract of DOI:10.1002/ejic.200900451

The chemistry of the mixed P,S-donor ligands [2-(1,3-dioxolan-2-yl)phenyl] diphenylphosphane (PhPOO, 1), and [2-(1,3-dithiolan-2-yl)phenyl] diphenylphosphane (PhPSS, 2) with the Ru^II precursors [RuCl ₂(PPh₃)3] and [RuCl

Full text of DOI:10.1002/ejic.200900451

FULL PAPER
DOI: 10.1002/ejic.200900451
Synthesis, Crystal Structures and NMR Spectroscopic Studies on Ruthenium
Complexes with Phosphanylacetal and Phosphanylthioacetal Ligands
Simon R. Bayly,[a] Andrew R. Cowley,[a] Jonathan R. Dilworth,*[a] and Caroline V. Ward[a]
Keywords: Ruthenium / Mixed-donor ligands / P ligands / S ligands / Homogeneous catalysis
The chemistry of the mixed P,S-donor ligands [2-(1,3-dioxol-
an-2-yl)phenyl]diphenylphosphane (PhPOO, 1), and [2-(1,3-
dithiolan-2-yl)phenyl]diphenylphosphane (PhPSS, 2) with
the RuII precursors [RuCl2(PPh3)3] and [RuCl2(4-cymene)]2
has been investigated. The structures of the resulting com-
plexes were analysed by X-ray crystallography and 1H, 13C
and 31P NMR spectroscopy, and their activity as catalysts for
oxolane complex 4 showed fluxional behaviour by NMR
spectroscopy, whereas did not. Reaction of PhPSS
with[RuCl2(PPh3)3] in methanol solution produced
[RuCl2(PhPSS)2] (5), and reaction with [RuCl2(4-cymene)]2
produced the cationic complex [RuCl(4-cymene)(PhPSS)]+ (6)
by precipitation with NaBPh4. In solution both 5 and 6 exist
in two isomeric forms, and neither shows evidence of fluxion-
ality at room temperature. Of the complexes tested only the
acetal species 3 showed any significant hydrosilylation ac-
tivity.
3
hydrosilylation was examined. Reaction of
1
with
[RuCl2(PPh3)3] in methanol solution produced [RuCl2-
(PhP(OMe)2)2] (3) {with [RuCl2(MeOH){PhP(OMe)2}(PPh3)]
(3a) as a side product}, whereas the same reaction with
[RuCl2(4-cymene)]2 produced [RuCl2(PhPOO)2] (4). The di-
(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
Germany, 2009)
Introduction
Results and Discussion
Ligand 1 is an intermediate in the preparation of 2-(di-
phenylphosphanyl)benzaldehyde.[7] Ligand 2 was prepared
from the reaction of 2-(diphenylphosphanyl)benzaldehyde,
p-toluenesulfonic acid monohydrate (TsOH) (5 mol-%) and
1,2-ethanedithiol, in ethanol. This ligand is soluble in many
solvents, including methanol, chlorinated solvents, diethyl
ether and hexane. Elemental analysis, positive-ion ESMS
and 1H and 31P NMR spectroscopy were all consistent with
the proposed formula.
The reaction of [RuCl2(PPh3)3] with PhPOO in methanol
resulted in the formation of trans-[RuIICl2(PhP(OMe)2)2]
(3). This complex is soluble in dichloromethane, sparingly
soluble in acetonitrile and insoluble in most other solvents
including diethyl ether and dimethyl sulfoxide. Identical
products are formed whether the stoichiometry of the reac-
tion is 1:1 or 1:2 for ruthenium precursor/ligand. The yield
is maximised with the higher ligand/metal ratio. The reac-
tion is surprising in that the dioxolane has been converted
to an acetal by reaction with solvent in the absence of
added acid. Complex 3 (Figure 1) is pseudo-octahedral in
geometry, with each of the PhP(OMe)2 ligands bound to
the metal centre in a bidentate fashion through the phos-
phorus atom and one of the OMe oxygen atoms, the re-
maining OMe group is pendant. The Ru–Cl bond lengths
are ca. 2.4 Å, Ru–O ca. 2.2 Å and Ru–P ca. 2.3 Å. These are
comparable with values for Ru–Cl, Ru–O and Ru–P bond
lengths in the literature.[8–11] Bond lengths within the acetal
groups are comparable with those of [ReCl(CO)3{2-
CH(OMe)2C5H4N}], which also contains one coordinated
There is considerable current interest in mixed-donor li-
gands combining phosphanyl donor groups with other do-
nor atoms.[1–3] As part of our investigation of mixed P,S-
donor ligands[4–6] we have been exploring the chemistry
of
[2-(1,3-dioxolan-2-yl)phenyl]diphenylphosphane
(1,
PhPOO),[7] and [2-(1,3-dithiolan-2-yl)phenyl]diphenylphos-
phane (2, PhPSS) (Scheme 1). As well as possessing an
enantiotopic carbon centre, these ligands have several pos-
sible binding modes, and have the potential to show hemi-
labile and fluxional behaviour. In this paper, we describe
the chemistry of 1 and 2 with various ruthenium(II) precur-
sors and detail the crystal structures and solution-phase
NMR spectroscopy of the complexes formed. The catalytic
activity of the complexes in a model hydrosilylation reac-
tion has also been investigated.
Scheme 1.
[a] Department of Chemistry, University of Oxford, Chemistry Re-
search Laboratory,
Mansfiled Road, OX1 3TA, United Kingdom
Fax: +44-1865-272690
E-mail: jon.dilworth@chem.ox.ac.uk
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S. R. Bayly, A. R. Cowley, J. R. Dilworth, C. V. Ward
FULL PAPER
and one pendant OMe group.[12] The molecular unit of 3 is as shown by the Flack parameter of 0.43(2). In principle,
chiral, and both stereogenic carbon centres are in the same therefore, it may be possible to separate the two enantio-
configuration. However, the centrosymmetric space group mers of this complex by crystallisation.
indicates that the crystal is racemic. Proton, carbon and
phosphorus NMR spectroscopy of 3 in CDCl3 gave sharp,
well-resolved spectra, and show the solution structure to be
consistent with that in the solid state.
Figure 2. ORTEP representation of 3a (40% thermal ellipsoids, hy-
drogen atoms omitted for clarity).
Reaction of [RuCl2(4-cymene)]2 with PhPOO under re-
flux in methanol resulted in the formation of a single iso-
mer, trans-[RuIICl2(PhPOO)2] (4). This complex is soluble
in chlorinated solvents but insoluble in hexane and diethyl
Figure 1. ORTEP representation of 3 (40% thermal ellipsoids, hy-
drogen atoms omitted for clarity).
A possible mechanism for the conversion of 1 to the ace- ether. The structure of the complex was determined by sin-
tal in the complex is that nucleophilic attack of the dioxol- gle-crystal X-ray diffraction analysis (Figure 3). The molec-
ane carbon atom by the solvent is promoted by coordina- ular unit is chiral, and both stereogenic carbon centres are
tion of the adjacent oxygen atom to the ruthenium centre. in the same configuration. However, the centrosymmetric
The metal atom could thus be acting as a Lewis acid cata- space group indicates that the crystal is racemic. The struc-
lyst for the hydrolysis. There are very few reported acetal ture shows the two phosphorus atoms and the two oxygen
complexes of ruthenium.[13] However, several diacetal–rhe- atoms to be cis to one another, and the two chlorido ligands
nium and –platinum complexes reported in the literature to be approximately trans, as in the structure of 3. The bond
have a similar structure, with only one oxygen atom of each angles are also very similar. For example, the Cl(1)–Ru(1)–
diacetal ligand coordinated to the metal centre and the sec- Cl(2) angle is 165.53(4)°. The Ru–Cl, Ru–O and Ru–P bond
ond alkoxy group pendant. NMR spectroscopy studies in lengths measure ca. 2.4 Å, ca. 2.2 Å and ca. 2.3 Å, respec-
solution have shown these complexes to be fluxional, with tively. Interestingly, the use of [RuCl2(4-cymene)]2 as the ru-
coordination switching between the two oxygen atoms of a thenium precursor in this reaction results in the dioxolane
single acetal group.[12] If this occurs in 3 at room tempera- ligand remaining intact. Lindner and co-workers have
ture it must be slower than the NMR spectroscopic times- studied a series of ruthenium complexes with phosphane–
1
cale, since both the H and 13C NMR spectra show two dioxolane ligands and demonstrated their potential as ring-
distinct methoxy signals. After recrystallisation of crude 3, opening metathesis polymerisation catalysts.[14–16] In some
the filtrate was allowed to stand in air, and a further species examples the dioxolane showed fluxional behaviour
crystallised. This was found to be [RuIICl2(MeOH)- though, to be dependent on the strength of the Ru–O bond
{PhP(OMe)2}(PPh3)] (3a) by X-ray crystal structure deter- as dictated by the co-ligands present at the ruthenium cen-
mination (Figure 2). In this case one PhP(OMe)2 ligand is tre. At ambient temperature in CDCl3 both the proton and
bound to the metal centre in the bidentate mode, and the carbon NMR spectra of 4 show several broad peaks. The
remainder of the pseudo-octahedral coordination sphere is 1H NMR spectrum contains two broad singlets at δ = 4.22
made up of two chlorido ligands, a triphenylphosphane li- and 4.75 ppm attributed to the CH2 groups and a third at
gand (from the Ru precursor) and a methanol molecule. δ = 6.43 ppm corresponding to the CH groups. Sharp mul-
The bond lengths and angles of 3a are very similar to those tiplets due to the phenyl protons are observed in the range
of 3. The Ru–O bonds of the coordinated PhP(OMe)2 and 6.65–7.81 ppm. In the 13C NMR spectrum a broad singlet
MeOH ligands differ, however [these are 2.274(2) Å and is present at δ = 65.5 ppm due to the overlapping CH2
2.209(2) Å, respectively]. Complex 3a crystallised in a non- group signals, a single peak at δ = 101.8 ppm for the equiva-
centrosymmetric space group, but is twinned by inversion lent CH groups and the phenyl carbon resonances are ob-
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Ruthenium Complexes with P,S-Donor Ligands
served in the range δ = 125.7–139.6 ppm. At this tempera- occur. Upon warming to room temperature the original
ture the 31P NMR spectrum shows a single peak at δ = spectra were observed again. This dynamic process is sim-
54.36 ppm. The observed spectral broadening is presumably ilar to that observed for acetal–rhenium and –platinum
the result of a fluxional process. Two types of fluxional be- complexes.[12] It is interesting that complex 4 shows flux-
haviour are possible. Firstly, two or more of the five pos- ional behaviour in the NMR spectrum (between –30 and
sible geometrical isomers could be present in solution with 50 °C), with evidence for both rotation of the acetal group
interconversion taking place between them on the NMR and geometric reorganisation, whereas complex 3 appears
spectroscopic timescale. The second possibility is that the rigid at room temperature. Possibly the orientation of the
Ru–O bond in the complex is sufficiently labile, such that methyl groups in the latter offers more steric resistance to
rotation about the C–C bond between the phenyl ring and rotation than the dioxolane group of the former.
the two oxygen atoms brings first one oxygen atom of each
Reaction of [RuCl2(PPh3)3] with PhPSS in refluxing
ligand into contact with the metal centre and then the other methanol produced [RuCl2(PhPSS)2] (5) in good yield. To
(Scheme 2).
the best of our knowledge this is the first reported ruthe-
nium complex of a phosphanyl–dithiolane ligand. The 31P
NMR (CDCl3) spectrum shows two doublets and a singlet
[δ = 30.1 (JP-P = 27 Hz), 32.6 (JP-P = 27 Hz), 46.1 ppm],
which indicates the presence of two species. The species ap-
pear to be stable over time in CDCl3 and are likely to be
two of the five possible geometrical isomers of
5
(Scheme 3). Peak integration shows an approximately 1:1
ratio. Of the possible isomers, only A possesses inequivalent
phosphorus atoms, and hence the observed pair of doublets
at δ = 30.1 and 32.6 ppm are assigned to this isomer. The
dithiolane CH2 and CH groups in this isomer are also in-
equivalent. The diastereotopic CH2 protons give rise to
eight individual signals between δ = 2.58 and 4.80 ppm in
the 1H NMR spectrum, whereas the CH protons give values
of δ = 5.54 and 6.04 ppm, respectively. The second isomer
could not be identified by NMR spectroscopy alone, but
must be more symmetrical since it shows only four signals
due to CH2 protons (δ = 3.12–3.48 ppm) and one signal for
the CH proton (δ = 6.52 ppm).
Figure 3. ORTEP representation of 4 (40% thermal ellipsoids, hy-
drogen atoms omitted for clarity).
Scheme 2. Possible rotation around the C–C bond of PhPOO.
Variable-temperature 1H and 31P NMR spectroscopy ex-
periments were carried out. Upon increasing the tempera-
ture to 50 °C the proton spectrum became sharper, espe-
cially in the CH2 and CH regions. Presumably, the increase
in temperature causes the isomers to interconvert more
rapidly and/or speeds up rotation about the C–C bond of
the ligand. Upon decreasing the temperature to –20 °C and
then to –30 °C, these same peaks also became much
sharper, and several multiplets were observed in both the
Scheme 3. Geometrical isomers of [RuCl2(PhPSS)2] (5).
The structure of complex 5 was determined by single-
CH2 and CH regions. At –30 °C the broad signal at δ = crystal X-ray diffraction analysis (Figure 4), and shows the
65.5 ppm in the room-temperature 13C NMR spectrum is two phosphorus atoms, both chlorido ligands and both sul-
separated into several sharp singlets, and the 31P NMR fur atoms to be trans to one another, corresponding to iso-
spectrum displays a whole range of singlet and doublet mer B. This is in contrast to the structure obtained of 4 in
peaks. The multiplets seen in the 31P NMR spectrum sug- which the chlorido ligands are trans to one another but
gest that several isomers are present at low temperature, both phosphorus and oxygen atoms are cis. Similar bond
with both cis and trans phosphane ligands. The appearance angles occur in both structures, however. For example, in 5
of isomers at low temperature is analogous to the room- the P(1)–Ru(1)–S(1) angle is 88.81(4)° and the analogous
temperature behaviour of the more rigid PSS ligands dis- angle in 4 [P(1)–Ru(1)–O(1)] is 86.6(1)°. Interestingly, the
cussed below. The lability of the O-donor atom of the diox- Ru–P bond of 2.3836(12) and 2.3976(12) Å are substan-
olane permits reorganisation of the coordination sphere to tially longer than the corresponding Ru–P bonds of 4
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S. R. Bayly, A. R. Cowley, J. R. Dilworth, C. V. Ward
FULL PAPER
[2.2649(12) and 2.2562(13) Å]. Ru–Cl bond lengths are sim- in chloroform and insoluble in hexane, methanol and di-
ilar in both structures (Table 1). The structure of 5 is chiral, ethyl ether. Unlike the previous complexes 3, 4 and 5, there
and both stereogenic carbon centres are in the same config- is no evidence for the formation of the disubstituted species.
uration. However, as before, the centrosymmetric space This is possibly because the cymene ring stabilises the hetero-
group indicates that the crystal is racemic.
leptic complex against further ligand substitution. The 31P
NMR spectrum in [D6]DMSO shows two singlets at δ =
29.2 and 36.2 ppm, consistent with the presence of two iso-
mers in approximately equal proportions. Four dithiolane
CH2 signals are observed at δ = 3.62, 3.73, 3.89 and
4.32 ppm in the 1H NMR spectrum and two dithiolane CH
resonances at δ = 4.48 and 5.92 ppm. In the 13C NMR spec-
trum only two dithiolane CH2 group signals are observed
at δ = 32.2 and 35.4 ppm, which is presumably due to the
two CH2 groups in each isomer having coincident chemical
shifts. The dithiolane CH groups have resonances at δ =
51.4 and 56.1 ppm. Further investigation is required to cor-
relate each set of signals to a specific isomer. The structure
of complex 6 was determined by single-crystal X-ray dif-
fraction analysis (Figure 5). The centrosymmetric space
group indicates that the crystal is racemic. In this structure
the ruthenium atom lies 1.75 Å from the plane of the C6
ring. The ring is coordinated symmetrically, and the ring
centroid–ruthenium vector lies only 0.3° from the normal to
the plane of best fit. Interesting bond angles include Cl(1)–
Ru(1)–S(1) and P(1)–Ru(1)–S(1) [89.66(2) and 85.23(2)°,
respectively], both of which are close to 90°. The PhPSS
ligand is bound almost symmetrically with respect to the
coordinated cymene. The Ru–C (ca. 2.2–2.3 Å), Ru–Cl (ca.
2.4 Å), Ru–P (ca. 2.3 Å) and Ru–S (ca. 2.3 Å) bond lengths
are similar to those of 5 and are consistent with those of
other reported ruthenium(II) complexes.[9,17,18]
Figure 4. ORTEP representation of 5 (40% thermal ellipsoids, hy-
drogen atoms omitted for clarity).
Table 1. Selected bond lengths and angles for complexes 3–6.
3
Ru(1)–Cl(1) 2.3958(8)
Ru(1)–P(1) 2.2668(9)
Ru(1)–O(1) 2.221(2)
Cl(1)–Ru(1)–Cl(2) 167.87(3)
Cl(1)–Ru(1)–P(1)
Cl(2)–Ru(1)–P(1)
87.86(3)
101.68
Cl(1)–Ru(1)–O(1) 89.97(6)
P(1)–Ru(1)–O(1)
P(1)–Ru(1)–P(2)
Cl(1)–Ru(1)–Cl(2) 164.12(3)
Cl(1)–Ru(1)–P(1) 89.41(3)
Cl(1)–Ru(1)–O(1) 89.41(3)
P(1)–Ru(1)–O(1)
P(1)–Ru(1)–P(2)
90.63(6)
100.49(3)
3a
4
Ru(1)–Cl(1) 2.3722(7)
Ru(1)–P(1)
2.2688(8)
Ru(1)–O(1) 2.274(2)
89.63(6)
89.63(6)
Cl(1)–Ru(1)–O(3) 85.45(6)
Ru(1)–Cl(1) 2.3923(11) Cl(1)–Ru(1)–Cl(2) 165.53(4)
Ru(1)–P(1)
Ru(1)–O(1) 2.202(3)
2.2649(12) Cl(1)–Ru(1)–P(1)
Cl(2)–Ru(1)–P(1)
90.69(4)
102.36(4)
Cl(1)–Ru(1)–O(1) 88.2(1)
P(1)–Ru(1)–O(1)
P(1)–Ru(1)–P(2)
O(1)–Ru(1)–P(2)
86.6(1)
99.26(5)
173.9(1)
5
6
Ru(1)–Cl(1) 2.4046(11) Cl(1)–Ru(1)–Cl(2) 179.42(4)
Ru(1)–P(1)
Ru(1)–S(1)
2.4046(11) Cl(1)–Ru(1)–P(1)
2.3421(11) Cl(1)–Ru(1)–S(1)
P(1)–Ru(1)–S(1)
90.82(4)
93.06(4)
88.81(4)
90.12(4)
175.96(4)
2.290(2)
86.29(2)
89.66(2)
85.23(2)
S(1)–Ru(1)–P(2)
P(1)–Ru(1)–P(2)
Ru(1)–C(22)
Cl(1)–Ru(1)–P(1)
Cl(1)–Ru(1)–S(1)
P(1)–Ru(1)–S(1)
Figure 5. ORTEP representation of [6]+ (40% thermal ellipsoids,
hydrogen atoms omitted for clarity).
Ru(1)–Cl(1) 2.3969(6)
Ru(1)–P(1)
Ru(1)–S(1)
2.3246(7)
2.3388(6)
Hydrosilyation Catalysis
The [RuCl(4-cymene)(PhPSS)]BPh4 complex 6 was syn-
The newly synthesised complexes were screened for their
thesised by the reaction of [RuCl2(4-cymene)]2 with 2 in activity towards the hydrosilylation of acetophenone to 1-
methanol, followed by precipitation with NaBPh4 This phenylethanol by using diphenylsilane. Hydrosilylation is a
complex is soluble in dimethyl sulfoxide, sparingly soluble generally accepted indicator of catalytic activity. Four
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Ruthenium Complexes with P,S-Donor Ligands
1
sources and were used as received. H, 13C and 31P NMR spectra
known complexes were used as a standard: [Ru2Cl4(4-cy-
mene)2], [RuCl2(PPh3)3],[19] [RuCl2(dppe)2][20] and [RuCl2-
(PhPOMe)2].[21,22] The method used was adapted from the
procedure described by Uemura, Hidai et al.[23] The results
are shown in Table 2. Of the four new complexes tested only
the acetal complex [RuCl2{PhP(OMe)2}2] (3) showed cata-
lytic activity, with the dioxolane and dithiolane complexes
giving sub-stoichiometric conversion.
of the redissolved isolated solids were recorded with a Varian Mer-
cury-Vx 300 spectrometer at 300.0, 75.4 and 121.4 MHz, respec-
tively, or a Varian Unit 500 MHz spectrometer at 499.9 MHz,
125.7 MHz and 202.4 MHz, respectively, at ambient temperature
unless otherwise stated. H and 13C NMR spectra were referenced
1
internally to residual solvent resonances or tetramethylsilane at δ
= 0 ppm (for 1H NMR), and 31P NMR spectra were externally
referenced to 85% H3PO4 at δ = 0 ppm. Electrospray mass spec-
trometry was performed with a Micromass LCT time of flight mass
spectrometer. Electron impact mass spectrometry was performed
with a Micromass GCT time of flight mass spectrometer, with a
heated solid probe. FAB mass spectrometry was performed with a
Fisons Autospec instrument, using dithiothreitol and dithioerythri-
tol or m-nitrobenzyl alcohol as the matrix. HPLC was carried out
with a GILSON analytical/preparative instrument and a UV/Vis
detector (λ = 250 nm). A reverse-phase HAMILTON PRP-1 ana-
lytical column (4.1ϫ150 mm, 10 µm) was used with an isocratic
mobile phase of acetonitrile/water (95%:5%) and a flow rate of
1.5 mL/min. Gas chromatography was carried out with a Unicam
ProGC gas chromatogram system using helium as the carrier gas
and a Flame Ionisation Detector (FID) with a hydrogen/air flame.
A 2 m Carbowax 20M packed column was used. Elemental analy-
ses were carried out by the elemental analysis service of the Inor-
ganic Chemistry Laboratory, University of Oxford. X-ray crystal-
lography was performed with a Bruker-Nonius KappaCCD dif-
fractometer, using graphite-monochromated Mo-Kα radiation (λ =
0.71073 Å). Single crystals were mounted on a glass fibre using
perfluoropolyether oil and cooled rapidly to 150 K in a stream of
cold nitrogen using an Oxford Cryosystems CRYOSTREAM unit.
Intensity data were processed using the DENZO-SMN package.[24]
Structures were solved using the direct-methods programme
SIR92,[25] which located all non-hydrogen atoms. Subsequent full-
matrix least-squares refinement was carried out using the CRYS-
TALS programme suite.[26] Coordinates and anisotropic thermal
parameters of all non-hydrogen atoms were refined. Hydrogen
atoms were positioned geometrically after each cycle of refinement.
A 3-term Chebychev polynomial weighting scheme was applied.
Crystallographic data is shown in Table 3. CCDC-666148 (3),
-666149 (3a), -666150 (4), -666151 (5), -666152 (6) contain the sup-
plementary crystallographic data for this paper. These data can be
obtained free of charge from The Cambridge Crystallographic
Data Centre via www.ccdc.cam.ac.uk/data_request/cif.
Table 2. Results of catalytic hydrosilylation by using PXXЈ com-
plexes compared to known catalysts.
Catalyst
Conversion [%][a]
[RuCl2(PPh3)3]
[RuCl2(4-cymene)]2
19
1
[RuCl2(dppe)2]
0.2
3
0.4
0.2
0
16
0.5
[RuCl2{PhP(OMe)2}2] (3)
[RuCl2(PhPOO)2] (4)
[RuCl2(PhPSS)2] (5)
[RuCl(cymene)(PhPSS)]BPh4 (6)
[RuCl2(PhPOMe)2]
[RuCl(PhPNO-η6-C6H5)Cl]BPh4
[a] Under the experimental conditions conversion [%] = TON =
TOF [h–1].
Conclusions
Reaction of ruthenium(II) precursors with 1 and 2 gen-
erally produced complexes in which the mixed-donor li-
gands bind in a bis(bidentate) fashion. Reaction of 1 with
[RuCl2(PPh3)3] led to the conversion of the dioxolane to the
dimethyl acetal by reaction with the solvent, whereas in the
reaction with [RuCl2(4-cymene)]2 the dioxolane remained
intact. Dioxolane complex 4 showed fluxional behaviour at
room temperature in CDCl3 solution with several isomers
1
visible in the H, 13C and 31P NMR spectra. In contrast, in
the solution phase, 3 appears (at room temperature) to exist
as a single isomer, corresponding to its solid-state structure.
Both dithiolane complexes 5 and 6 exist as mixtures of geo-
metric isomers in CDCl3 solution, but there is no evidence
of interconversion at room temperature. The kinetic sta-
bility provided by the strength of the Ru–S bonds is also
likely to be the reason why these complexes do not show
any catalytic activity. In comparison, the Ru–O bonding in
3 and 4 is presumably weaker and leads to the fluxional
behaviour of 4, and although the acetal donor groups in 3
did not appear to be labile, it was only this species which
showed any activity in hydrosilylation catalysis.
PhPSS (2): 2-(Diphenylphosphanyl)benzaldehyde (669 mg,
2.31 mmol) and p-toluenesulfonic acid monohydrate (13 mg,
0.07 mmol) were suspended in non pre-dried ethanol (50 mL), and
the reaction mixture was heated gently to give a yellow solution.
1,2-Ethanedithiol (0.19 mL, 2.31 mmol) was added, and the reac-
tion mixture was heated at just below reflux temperature overnight.
The now colourless solution was cooled to room temperature, and
the volume of solvent was reduced in vacuo to produce a white
precipitate. This was collected by filtration in air, washed with etha-
nol and dried in vacuo. PhPSS was obtained as a white powdery
solid (565 mg, 67%). C21H19PS2 (366.48): calcd. C 68.8, H 5.2;
Experimental Section
General: Unless otherwise stated, all manipulations were carried
out under dinitrogen with dry solvents and using Schlenk line tech-
niques. Solvents were pre-dried with sodium wire or calcium chlo-
ride prior to heating at reflux over the appropriate drying agent/
indicator: methanol (magnesium methoxide), tetrahydrofuran (so-
dium/benzophenone), toluene (sodium). All solvents were degassed
prior to use. [RuCl2(PPh3)3][19] and 2-(diphenylphosphanyl)benz-
aldehyde[7] were prepared according to literature procedures. All
other reagents and solvents were purchased from commercial
found C 68.6, H 5.0. FTIR (nujol mull): ν = 1000–1500 cm–1; no
˜
S=O stretch. MS (ES+): m/z = 367 [M]+, 339 [M – CH2CH2]+.
HPLC: tr = 5.48 min. H NMR (CDCl3): δ = 3.25 (m, 2 H, H1 or
1
H2), 3.42 (m, 2 H, H1 or H2), 6.48 (d, JH-P = 9 Hz, 1 H, H3), 6.82
(m, JH5-H6 = 8, JH5-H7 = 4 Hz, 1 H, H5), 7.11 (m, JH6-H5 = 8,
JH6-H7 = 8, JH6-H8 = 1 Hz, 1 H, H6), 7.22–7.37 (m, 10 H, Ph), 7.31
(m, JH7-H5 = 4, JH7-H6 = 8, JH7-H8 = 7 Hz, 1 H, H7), 7.93 (m, JH-P
= 5, JH8-H6 = 1, JH8-H7 = 7 Hz. 1 H. H8) ppm. 31P NMR (CDCl3):
δ = –16.4 ppm. 13C NMR (CDCl3): δ = 40.4 (s, C1, C2), 53.5 (d,
Eur. J. Inorg. Chem. 2009, 3807–3813
© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
3811

S. R. Bayly, A. R. Cowley, J. R. Dilworth, C. V. Ward
FULL PAPER
Table 3. Crystallographic data for complexes 3–6.
3
3a
4
5
6
Empirical formula
C42H42Cl2O4P2Ru
C41H44Cl2O4P2Ru
C45H41Cl11O4P2Ru
C42H41Cl11P2RuS4
C55H53BClPRuS2·
xC2H3N·yH2O
(x ≈ 0.69, y ≈ 0.21)
988.58
Formula mass
T [K]
844.72
150
834.72
150
1198.82
150
1263.06
150
150
λ [Å]
Crystal system
Space group
0.71073
orthorhombic
Pbcn
0.71073
monoclinic
Pn
0.71073
triclinic
P1
0.71073
triclinic
P1
0.71073
monoclinic
P21/c
¯
¯
a [Å]
b [Å]
c [Å]
α [°]
29.8017(3)
11.3137(2)
22.3869(2)
90
90
90
7584.14(17)
8
1.487
11.1725(2)
11.7916(2)
14.8140(3)
90
94.0849(9)
90
1946.7
2
1.424
11.4441(3)
15.0416(3)
16.4074(4)
113.2293(11)
102.6241(11)
95.5941(12)
2487.9
10.0250(2)
12.1110(2)
22.3615(3)
104.4111(5)
98.8140(5)
95.5039(7)
2572.9
9.8503(2)
19.3006(2)
25.7455(2)
90
98.6551(5)
90
4838.9
4
1.344
0.536
β [°]
γ [°]
V [Å3]
Z
2
2
D [Mg/m3]
1.606
1.016
1.630
1.134
µ [mm–1]
0.684
0.662
F(000)
3467.79
0.08ϫ0.08ϫ0.14
61345
858.196
0.18ϫ0.24ϫ0.24
18668
1208.600
0.20ϫ0.20ϫ0.24
35503
1273.423
0.06ϫ0.12ϫ0.12
41689
2049.565
0.18ϫ0.22ϫ0.22
60370
Crystal size [mm]
Reflections mea-
sured
Unique reflections
Rint
Parameters refined
Goodness of fit
R
9394
0.054
460
1.0681
0.0306
0.0298
8244
0.036
460
1.0962
0.0285
0.0281
11296
0.047
568
0.9879
0.0739
0.0802
11672
0.066
568
1.0351
0.0527
0.0593
11012
0.058
568
1.0382
0.0367
0.0436
wR
JC-P = 33 Hz, C3), 127.9 (s, C6), 128.5 (d, JC-P = 7 Hz, Ph), 128.7 (CDCl3): δ = 54.4 ppm. 13C NMR (CDCl3): δ = 65.5 (br. s, CH2,
(d, JC-P = 5 Hz, C8), 128.8 (s, Ph), 129.6 (s, C7), 133.4 (s, C5), 133.8
CH2Ј), 101.8 (s, CH), 125.7–139.6 (Ph) ppm.
(d, JC-P = 20 Hz, Ph), 135.6 (d, JC-P = 13 Hz C4), 136.2 (d, JC-P
10 Hz, Ph), 145.1 (d, JC-P = 23 Hz, C9) ppm.
=
[RuCl2(PhPSS)2] (5): [RuCl2(PPh3)3] (184 mg, 0.19 mmol) and
PhPSS (141 mg, 0.39 mmol) were suspended in methanol (15 mL)
[RuCl2{PhP(OMe)2}2] (3): [RuCl2(PPh3)3] (247 mg, 0.26 mmol) and and the reaction mixture was heated under reflux for 6 h. The col-
PhPOO (172 mg, 0.51 mmol) were suspended in methanol (15 mL)
and heated at reflux overnight. The reaction mixture became
orange in colour, and an orange precipitate formed. This was col-
lected by filtration in air, washed with methanol and dried in vacuo.
[RuCl2{PhP(OMe)2}2] was obtained as an orange solid (217 mg,
58%). C42H42Cl2O4P2Ru (844.70): calcd. C 59.7, H 5.0; found C
60.1, H 5.1. MS (ES+): m/z = 844 [M]+, 809 [M – Cl]+, 776 [M – 2
our changed from brown to yellow, and a yellow precipitate
formed. After cooling to room temperature, the precipitate was col-
lected by filtration in air, washed with methanol and dried in vacuo.
[RuCl2(PhPSS)2] was obtained as a yellow powder (131 mg, 75%).
C42H38Cl2P2RuS4 (904.93): calcd. C 55.8, H 4.2; found C 56.1, H
3.9. MS (FAB+): m/z = 906.0 [M]+, 869.0 [M – Cl]+, 834.0 [M – 2
1
Cl]+, 467.0 [M – (2 Cl + PSS)]+. H NMR (CDCl3): isomer 1: δ =
Cl]+, 712 [M – (2 Cl + 2 OMe)]+. HPLC: tr = 4.98 min. H NMR
2.58 (m, JH-H = 7 Hz, 1 H, CH2H1), 3.27 (m, 1 H, CH2H2), 3.45
1
(CDCl3): δ = 3.39 (s, 6 H, OMe1), 3.55 (s, 6 H, OMe2), 6.70 (s, 2 (m, JH-H = 7, 2 Hz, 1 H, CH2H3), 3.55 (m, JH-H = 11, 7, 4 Hz, 1
H, CH), 6.89–7.80 (m, 20 H, Ph), 7.28 (m, JH-H = 8, 1 Hz, 2 H,
H3), 7.39 (m, JH-H = 8, 1 Hz, 2 H, H4), 7.46 (m, JH-P = 3, JH-H
8, 1 Hz, 2 H, H5), 7.76 (m, JH-H = 8 Hz, 2 H, H6) ppm. 31P NMR 4.80 (m, JH-H = 9, 2 Hz, 1 H, CH2H8), 5.54 (d, JH-P = 2 Hz, 1 H,
(CDCl3): δ = 48.2 ppm. 13C NMR (CDCl3): δ = 48.3 (s, OMe), CH H9), 6.04 (s, 1 H, CH H10) ppm; isomer 2: δ = 3.12 (m, 2 H,
56.2 (s, OMe), 103.0 (s, CH), 126.7 (s, Ph), 127.0 (s, C6), 128.5 (d, CH2H11), 3.30 (m, 2 H, CH2H12), 3.33 (m, 2 H, CH2H13), 3.48 (m,
JC-P = 12 Hz, Ph), 128.8 (s, C4), 129.3 (d, JC-P = 24 Hz, Ph), 131.1 2 H, CH2H14), 6.52 (s, 2 H, CH H15) ppm; isomers 1 + 2: δ = 6.42–
(s, C3), 131.9 (d, JC-P = 3 Hz, Ph), 132.1 (d, JC-P = 10 Hz, C5), 8.06 (m, 56 H, Ph) ppm. 31P NMR (CDCl3): isomer 1: δ = 30.1 (d,
H, CH2H4), 3.67 (m, JH-H = 7 Hz, 1 H, CH2H5), 4.05 (m, JH-H
11, 7, 4 Hz, 1 H, CH2H6), 4.74 (m, JH-H = 2 Hz, 1 H, CH2H7),
=
=
134.9 (s, Ph), 138.3 (s, Ph) ppm.
JP–P = 27 Hz), 32.6 (d, JP–P = 27 Hz) ppm; isomer 2: δ = 46.1 ppm.
13C NMR (CDCl3): isomer 1: δ = 35.8 (s, CH2 C2, C4), 39.1 (s,
CH2 C5, C7), 39.8 (s, CH2 C1, C6), 41.4 (s, CH2 C3, C8), 56.6 (d,
JC-P = 11 Hz, CH C9), 62.0 (d, JC-P = 10 Hz, CH C10) ppm; isomer
2: δ = 34.8 (s, CH2 C11, C12), 36.2 (s, CH2 C13, C14), 61.5 (d, JC-P
= 11 Hz, CH15) ppm; isomers 1 + 2: δ = 127.1–138.2 (Ph) ppm.
[RuCl2(PhPOO)2] (4): Tetrachlorobis(4-cymene)diruthenium
(98 mg, 0.16 mmol) and PhPOO (214 mg, 0.64 mmol) were dis-
solved in methanol (15 mL) and were heated under reflux over-
night. The reaction mixture became orange in colour, and an
orange precipitate formed. This was collected by filtration in air,
washed with methanol and dried in vacuo. [RuCl2(PhPOO)2] was
obtained as a pink/orange powder (188 mg, 70%). C42H38Cl2O4-
P2Ru (840.67): calcd. C 60.0, H 4.6; found C 60.3, H 4.6. MS (ES+):
m/z = 805 [M – Cl]+, 770 [M – 2 Cl]+. HPLC: tr = 3.50 min. 1H
NMR (CDCl3): δ = 4.22 (br. s, 4 H, CH2), 4.75 (br. s, 4 H, CH2Ј),
[RuCl(cymene)(PhPSS)]BPh4 (6): Tetrachlorobis(4-cymene)diru-
thenium (56 mg, 0.09 mmol) and PhPSS (134 mg, 0.37 mmol) were
suspended in methanol (15 mL), and the reaction mixture was
heated at reflux for 6 h. An orange solution formed, and, after
cooling to room temperature, a methanolic solution of sodium tet-
6.43 (br. s, 2 H, CH), 6.65–7.81 (m, 28 H, Ph) ppm. 31P NMR: raphenylborate (310 mg, 0.91 mmol, in 5 mL of non pre-dried
3812 Eur. J. Inorg. Chem. 2009, 3807–3813
www.eurjic.org
© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Ruthenium Complexes with P,S-Donor Ligands
methanol) was added. A yellow/orange precipitate formed and was
collected by filtration in air, washed with methanol and diethyl
ether and dried in vacuo. [RuCl(cymene)(PhPSS)]BPh4 was ob-
tained as a yellow powder (156 mg, 90%). C55H53BClPRuS2
(956.45): calcd. C 69.1, H 5.6; found C 69.1, H 5.6. MS (ES+): m/z
of materials and Dr. N. H. Rees of the University of Oxford for his
assistance with NMR spectroscopy.
[1] C. Bolzati, M. Cavazza-Ceccato, S. Agostini, F. Tisato, G. Ban-
doli, Inorg. Chem. 2008, 47, 11972–11983.
1
= 637 [M]+, 602 [M – Cl]+. HPLC: tr = 1.18 min. H NMR ([D6]-
[2] S. Kealey, N. J. Long, P. W. Miller, A. J. P. White, P. B. Hitch-
cock, A. Gee, Dalton Trans. 2007, 2823–2832.
[3] G. Müller, A. Feustel, Organometallics 2003, 22, 3049–3058.
[4] S. R. Bayly, A. R. Cowley, J. R. Dilworth, C. V. Ward, Dalton
Trans. 2008, 2190–2198.
DMSO): isomer 1: δ = 1.05 (d, JH-H = 7 Hz, 3 H, Me), 1.15 (d,
JH-H = 7 Hz, 3 H, MeЈ), 2.16 (s, 3 H, Mecy), 2.65 (m, JH-H = 7 Hz,
1 H, CH), 4.92 (d, JH-H = 5 Hz, 1 H, H3cy), 5.48 (d, JH-H = 6 Hz,
1 H, H2cy), 6.03 (d, JH-H = 5 Hz, 1 H, H2Јcy), 6.30 (d, 1 H, H3Јcy
)
[5] J. R. Dilworth, N. Wheatley, Coord. Chem. Rev. 2000, 199, 89–
ppm; isomer 2: δ = 0.91 (d, JH-H = 7 Hz, 3 H, Me), 1.09 (d, JH-H
= 7 Hz, 3 H, MeЈ), 1.96 (s, 3 H, Mecy), 2.45 (m, JH-H = 7 Hz, 1 H,
CH), 5.91 (s, 1 H, H6cy), 6.11 (d, JH-H = 6 Hz, 1 H, H6Јcy), 6.22 (d,
JH-H = 6 Hz, 1 H, H7cy), 6.28 (d, 1 H, H7Јcy) ppm; isomers 1 + 2:
δ = 3.62 (m, JH-H = 12, 7 Hz, 2 H, CH2PSS), 3.73 (m, JH-H = 12,
7 Hz, 2 H, CH2PSS), 3.89 (m, JH-H = 13, 7 Hz, 2 H, CH2PSS), 4.32
(m, 2 H, CH2PSS), 4.48 (s, 1 H, CHPSS), 5.92 (s, 1 H, CHPSS), 6.72–
7.99 (m, 48 H, Ph) ppm. 31P NMR ([D6]DMSO): δ = 29.2,
36.2 ppm. 13C NMR ([D6]DMSO): isomer 1: δ = 17.5 (s, Mecy),
20.7 (s, Me), 22.8 (s, MeЈ), 30.4 (s, CH), 104.4 (s, C1cy), 111.1 (s,
C4cy) ppm; isomer 2: δ = 15.2 (s, MeЈ), 17.3 (s, Mecy), 20.3 (s, Me),
29.4 (s, CH), 107.0 (s, C5cy), 113.3 (s, C8cy) ppm; isomers 1 + 2: δ
= 32.2 (s, CH2PSS), 35.4 (s, CH2PSS), 51.4 (s, CHPSS), 56.1 (s,
CHPSS), 89.3 (s, cy), 89.8 (s, cy), 91.6 (s, cy), 92.2 (s, cy), 92.4 (s,
cy), 94.2 (s, cy), 94.5 (s, cy), 97.6 (s, cy), 121.1–138.5 (Ph), 162.4–
158.
[6] P. Pérez-Lourido, J. Romero, J. A. García-Vázquez, J. Castro,
A. Sousa, L. Cooper, J. R. Dilworth, R. L. Richards, Y. Zheng,
J. A. Zubieta, Inorg. Chim. Acta 2003, 356, 193–202.
[7] J. E. Hoots, T. B. Rauchfuss, D. A. Wrobleski, Inorg. Synth.
1982, 21, 175–179.
[8] N. R. Champness, R. J. Forder, C. S. Frampton, G. Reid, J.
Chem. Soc., Dalton Trans. 1996, 7, 1261–1266.
[9] N. Taguchi, K. Kashiwabara, K. Nakajima, H. Kawaguchi, K.
Tatsumi, J. Organomet. Chem. 1999, 587, 290–298.
[10] Y. Yamamoto, K.-I. Sugawara, T. Aiko, J.-F. Ma, J. Chem.
Soc., Dalton Trans. 1999, 22, 4003–4008.
[11] Y. Yamamoto, R. Sato, F. Matsuo, C. Sudoh, T. Igoshi, Inorg.
Chem. 1996, 35, 2329–2336.
[12] M. L. Creber, K. G. Orrell, A. G. Osborne, V. Sik, M. B. Hurst-
house, A. Malik, J. Chem. Soc., Dalton Trans. 2000, 4218–4226.
[13] D. B. Grotjahn, H. C. Lo, Organometallics 1996, 15, 2860–
2862.
–
164.3 (BPh4 ) ppm.
[14] E. Lindner, S. Pautz, R. Fawzi, M. Steimann, Organometallics
1998, 17, 3006–3014.
Catalytic Hydrosilyation of Acetophenone: The method utilised to
ascertain the activity of the complexes was derived from that of
Nishibayashi et al.[23] The catalyst (0.01 mmol, 1 mol-%) was dis-
solved in tetrahydrofuran (10 mL), in a Schlenk flask. Acetophe-
none (117 µL, 1 mmol) was added, and the reaction mixture was
heated to 65 °C. An excess of diphenylsilane (371 µL, 2 mmol) was
added and the flask sealed. Heating continued for a further 1 h.
After cooling to room temperature, the reaction mixture was
quenched with non pre-dried methanol (1 mL), to consume the re-
maining silane. After stirring at room temperature for 30 min, 0.2 
hydrochloric acid (2.5 mL) was added to hydrolyse the silyl ether.
The reaction mixture was stirred in air overnight and was then
analysed by GC. Percentage conversions were calculated from the
ratio of areas of the eluted peaks of acetophenone and 1-phenyle-
thanol. Calibration using standards showed the two substances to
elute in a 1:1 ratio when equal amounts of both were injected. No
correction factors were therefore applied to the areas. Temperature
profile for GC analysis: maintain 60 °C for 2 min, increase 10 °C
per min for 14 min, maintain 200 °C for 4 min; injector tempera-
ture: 220 °C; detector temperature: 300 °C.
[15] E. Lindner, M. Haustein, H. A. Mayer, H. Kühbauch, K. Vri-
eze, B. de Klerk-Engels, Inorg. Chim. Acta 1994, 215, 165–172.
[16] B. de Klerk-Engels, J. H. Groen, K. Vrieze, A. Möckel, E.
Lindner, K. Goubitz, Inorg. Chim. Acta 1992, 195, 237–243.
[17] T. Suzuki, N. Taguchi, K. Kashiwabara, Acta Crystallogr.,
Sect. C 1996, 52, 2982.
[18] A. Del Zotto, B. Della Ricca, E. Zangrando, P. Rigo, Inorg.
Chim. Acta 1997, 261, 147–159.
[19] P. S. Hallman, T. A. Stephenson, G. Wilkinson, Inorg. Synth.
1970, 12, 237–240.
[20] C. W. Jung, P. E. Garrou, P. R. Hoffman, K. G. Caulton, Inorg.
Chem. 1984, 23, 726–729.
[21] J. C. Jeffrey, T. B. Rauchfuss, Inorg. Chem. 1979, 18, 2658–
2666.
[22] T. B. Rauchfuss, F. T. Patino, D. M. Roundhill, Inorg. Chem.
1975, 14, 652–656.
[23] Y. Nishibayashi, I. Takei, S. Uemura, M. Hidai, Organometal-
lics 1998, 17, 3420–3422.
[24] Z. Otwinowski, W. Minor, Methods Enzymol. 1997, 276, 307–
326.
[25] A. Altomare, G. Cascarano, G. Giacovazzo, A. Guagliardi,
M. C. Burla, G. Polidori, M. Camalli, J. Appl. Crystallogr.
1994, 27, 435.
[26] D. J. Watkin, C. K. Prout, J. R. Carruthers, P. W. Betteridge
and R. I. Cooper, CRYSTALS issue 11, Chemical Crystallogra-
phy Laboratory, Oxford, UK, 2001.
Acknowledgments
We thank the Engineering and Physical Sciences Research Council
(EPSRC) for financial support, Johnson-Matthey for the donation
Received: May 18, 2009
Published Online: July 22, 2009
Eur. J. Inorg. Chem. 2009, 3807–3813
© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
3813