Carbonyl substitution chemistry of some trimetallic transition metal cluster complexes with polyfunctional ligands

Article abstract of DOI:10.1016/j.jorganchem.2008.01.040

The trimetallic clusters [Ru₃(CO)₁₀(dppm)], [Ru₃(CO)₁₂] and [RuCo₂(CO)₁₁] react with a number of multifunctional secondary phosphine and tertiary arsine ligands to give products consequent on carbonyl substitution and, in the case of the secondary phosphines, PH activation. The reaction with the unresolved mixed P/S donor, 1-phenylphosphino-2-thio(ethane), HSCH₂CH₂PHPh ({double bond, long} LH₂), gave two products under various conditions which have been characterised by spectroscopic and crystallographic means. These two complexes [Ru₃(μ-dppm)(H)(CO)₇(LH)] and [Ru₃(μ-dppm)(H)(CO)₈(LH)Ru₃(μ-dpp m)(CO)₉], show the versatility of the ligand, with it chelating in the former and bridging two Ru₃ units in the latter. The stereogenic centres in the molecules gave rise to complicated spectroscopic data which are consistent with the presence of diastereoisomers. In the case of [Ru₃(CO)₁₂] the reaction with LH₂ gave a poor yield of a tetranuclear butterfly cluster, [Ru₄(CO)₁₀(L)₂], in which two of the ligands bridge opposite hinge wingtip bonds of the cluster. A related ligand, HSCH₂CH₂AsMe(C₆H₄CH ₂OMe), reacted with [RuCo₂(CO)₁₁] to give a low yield of the heterobimetallic Ru-Co adduct, [RuCo(CO)₆(SCH₂CH₂AsMe(C₆H ₄CH₂OMe))], which appears to be the only one of its type so far structurally characterised. The secondary phosphine, HPMe(C₆H₄(CH₂OMe)) and its oxide HP(O)Me(C₆H₄(CH₂OMe)) also react with the cluster [Ru₃(CO)₁₀(dppm)] to give carbonyl substitution products, [Ru₃(CO)₅(dppm)(μ₂-PMe(C₆ H₄CH₂OMe))₄], and [Ru₃H(CO)₇(dppm)(μ₂,η ¹-P({double bond, long}O)Me(C₆H₄CH₂OMe))]. The former consists of an open Ru₃ triangle with four phosphide ligands bridging the metal-metal bonds; the latter has the O atom symmetrically bridging one Ru-Ru bond, the P atom being attached to a non-bridged Ru atom.

Full text of DOI:10.1016/j.jorganchem.2008.01.040

Available online at www.sciencedirect.com
Journal of Organometallic Chemistry 693 (2008) 1738–1750
www.elsevier.com/locate/jorganchem
Carbonyl substitution chemistry of some trimetallic transition
metal cluster complexes with polyfunctional ligands
a
a
a,
a
*
Lindsay T. Byrne , Nicole S. Hondow , George A. Koutsantonis , Brian W. Skelton ,
A. Asgar Torabi a,1, Allan H. White a, S. Bruce Wild b
a Chemistry, M313, University of Western Australia, Crawley, WA 6009, Australia
b Research School of Chemistry, Australian National University, Canberra, ACT 0200, Australia
Received 2 November 2007; received in revised form 23 January 2008; accepted 24 January 2008
Available online 2 February 2008
Abstract
The trimetallic clusters [Ru3(CO)10(dppm)], [Ru3(CO)12] and [RuCo2(CO)11] react with a number of multifunctional secondary phos-
phine and tertiary arsine ligands to give products consequent on carbonyl substitution and, in the case of the secondary phosphines, PH
activation. The reaction with the unresolved mixed P/S donor, 1-phenylphosphino-2-thio(ethane), HSCH2CH2PHPh (@ LH2), gave two
products under various conditions which have been characterised by spectroscopic and crystallographic means. These two complexes
[Ru3(l-dppm)(H)(CO)7(LH)] and [Ru3(l-dppm)(H)(CO)8(LH)Ru3(l-dppm)(CO)9], show the versatility of the ligand, with it chelating
in the former and bridging two Ru3 units in the latter. The stereogenic centres in the molecules gave rise to complicated spectroscopic
data which are consistent with the presence of diastereoisomers. In the case of [Ru3(CO)12] the reaction with LH2 gave a poor yield of a
tetranuclear butterfly cluster, [Ru4(CO)10(L)2], in which two of the ligands bridge opposite hinge wingtip bonds of the cluster. A related
ligand, HSCH2CH2AsMe(C6H4CH2OMe), reacted with [RuCo2(CO)11] to give a low yield of the heterobimetallic Ru–Co adduct,
[RuCo(CO)6(SCH2CH2AsMe(C6H4CH2OMe))], which appears to be the only one of its type so far structurally characterised.
The secondary phosphine, HPMe(C6H4(CH2OMe)) and its oxide HP(O)Me(C6H4(CH2OMe)) also react with the cluster
[Ru3(CO)10(dppm)] to give carbonyl substitution products, [Ru3(CO)5(dppm)(l2-PMe(C6H4CH2OMe))4], and [Ru3H-
(CO)7(dppm)(l2,g1-P(@O)Me(C6H4CH2OMe))]. The former consists of an open Ru3 triangle with four phosphide ligands bridging
the metal–metal bonds; the latter has the O atom symmetrically bridging one Ru–Ru bond, the P atom being attached to a non-bridged
Ru atom.
Ó 2008 Elsevier B.V. All rights reserved.
Keywords: Ruthenium; Cobalt; Carbonyl substitution; Cluster; Thiol; Secondary phosphine
1. Introduction
by dihydrogen. This process creates large amounts of nox-
ious sulfur containing effluent and this needs to be con-
tained for both environmentally and industrially
important reasons [1,2]. Thus, the efficient use of our
remaining reserves is of utmost importance as some crude
oils have significant sulfurous impurities that act to poi-
son fluid cracking catalysts and it is timely that we under-
stand the way in which sulfur interacts with small
aggregates of metal atoms [3–5].
The oil industry is potentially reaching peak produc-
tion and as such the time for the utilisation of more mar-
ginal crude oils is approaching, typically those containing
large amounts of sulfurous compounds which require
removal by hydrodesulfurization over catalysts promoted
*
Corresponding author. Tel./fax: +61 8 6488 3177/7247.
Organometallic complexes, containing two or more
adjacent metals, have have been presented as models for
processes occurring at associated metal sites on the sur-
E-mail address: george.koutsantonis@uwa.edu.au (G.A. Koutsanto-
nis).
1
On leave from Zanjan University, Republic of Iran.
0022-328X/$ - see front matter Ó 2008 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2008.01.040

L.T. Byrne et al. / Journal of Organometallic Chemistry 693 (2008) 1738–1750
1739
faces of heterogeneous catalysts [6–9], and, because such
2.1.1. Preparation of [Ru3(l-dppm)(H)(CO)7
(SCH2CH2PPhH)] (2) and [Ru3(l-dppm)(H)(CO)8
(SCH2CH2PPhH)Ru3(l-dppm)(CO)9] (3)
complexes may display novel reactivity, notably the expec-
tation of enhanced selectivity, utilising the impact of
mutually cooperative metals on substrate molecules. The
role of the metal in dehydrosulfurization has been
explored recently [3,10–12], showing that the interaction
of chalcogenic ligands with transition metals is of major
interest. The existence of several different metal atoms in
an active catalyst provides many potential structural and
chemical alternatives for multisite binding and catalysis
of organic substrates or fragments on the metal particle
[13].
The chemistry of [Ru(l-dppm)(CO)10] (dppm = 1,2-
bis(diphenylphosphino)methane) [14] (1), is characterised
by the straightforward addition of numerous groups with-
out prior activation of the cluster [15]. The reactivity of 1
stems from the ability of the dppm ligand to prevent dis-
sociation of metal centres from the cluster. The complex
readily undergoes facile ligand transformation, eliminating
benzene and orthometallating another phenyl substituent
[16–19]. We have recently reported that the enhanced
reactivity of [Ru3(l-dppm)(CO)10] relative to the parent
carbonyl [Ru3(CO)12] appeared to be a result of the inabil-
ity of the cluster to effectively relieve steric congestion
imposed by the presence of the bulky bidentate dppm
ligand [15]. In extending this work we examine the reac-
tion of polyfunctional ligands containing diverse function-
To a solution of [Ru3(l-dppm)(CO)10] (1) (500 mg,
0.70 mmol) in toluene (80 mL) was added LH2 (80 lL,
0.70 mmol). The resulting solution was stirred and gently
warmed (ca. 60 °C) for 2 h. The solvent was removed in
vacuo and the residue chromatographed (TLC, 1/5 ace-
tone–hexanes) and the three resulting bands collected.
The first band (Rf = 0.35) was established (by IR) to be
unreacted starting material 1 (172 mg, 34%).
The second band (Rf = 0.28) was crystallised from ace-
tone to give red crystals of 2 (80 mg, 15%). X-ray quality
crystals were grown from CH2Cl2/EtOH. Anal. Calc. for
C40H33O7P3SRu3 ꢁ CH2Cl2: C, 43.23; H, 3.10. Found: C,
42.84; H, 3.74%. IR (CH2Cl2): m(CO) 2065w, 2052w,
1
2032m, 1988vs, 1979vs, 1961s cmꢂ1. H NMR (acetone-
d6; 500 MHz) (nb. coupling constants for major isomer
1
only) d 7.9–7.1 (m, Ph), 6.28 (d, 1H, JPH = 355 Hz,
1
PH(major)), 6.11 (ddd, 1H, JPH = 351, J = 9.9, 3.6 Hz,
PH(minor)),
5.11
(ddd,
1H(major) + 1H(minor),
2JHH = 15.3 (geminal), JPH = 11.3, 9.6 Hz, PCH2P), 4.40
(dt, 1H(major) + 1H(minor), 2JHH = 15.3 (geminal),
2JPH = 10.8, 10.8 Hz, PCH2P), 2.50 (m, 2H, PCH2, major),
2.41 (m, 2H, PCH2, minor), 2.09 (m, 2H, SCH2, major + -
minor), 1.70 (m, 1H, SCH2, major), 1.22 (m, 1H, SCH2,
minor), ꢂ15.74 (dd, 1H, J = 41, 10.5 Hz, RuH, minor)
ꢂ15.99 (ddt, 1H, J = 41, 11.6, 2 Hz, RuH, major)
2
ality,
particularly
1-phenylphosphino-2-thio(ethane),
3
HSCH2CH2PHPh (@ LH2), with homometallic clusters
[Ru3(CO)12] and [Ru(l-dppm)(CO)10], and heterometallic
[RuCo2(CO)11]. In this way the influences of various
functionalities can be assessed for comparison with cata-
lytic systems.
31P{1H} NMR (acetone-d6) d 37.49 (dd, Jpp = 30.2, 8.2
3
PH, minor), 31.97 (dd, Jpp = 28.2, 8.2 PH, major), 21.44
(m, PCH2, minor), 21.86 (m, PCH2, major), 14.28 (dd,
2
3
obscured JPP = ca. 57, JPP = 29.7 Hz, PCH2, minor),
2
3
14.02 (dd, obscured JPP = 51.8, JPP = 27.8 Hz, PCH2,
minor). FABMS (NOBA) m/z 1052, [M+]; 1024–858,
[MꢂnCO]+ n = 1–7.
2. Experimental
The third band (Rf = 0.18) was crystallised from acetone
to give red crystals of 3 (158 mg, 15%). Crystals for analysis
were grown from CH2Cl2/EtOH and from acetone/hexane
for X-ray structural determination. Anal. Calc. for
C75H55O17P4SRu6 ꢁ CH2Cl2: C, 43.33; H, 2.73. Found: C,
43.31; H, 2.98%. IR (CH2Cl2): m(CO) 2065m, 2053w,
2.1. Syntheses
The reactions were conducted under atmospheres of
high purity argon using standard Schlenk techniques and
tetrahydrofuran (THF) dried over potassium metal.
[Ru3(l-dppm)(CO)10] was prepared using the published
procedure [20]. NMR spectra were measured on Bruker
ARX 300 (1H at 300.13 MHz, 13C at 75.5 MHz and 31P
at 121.5 MHz) and Bruker ARX 500 (1H at 500.13
MHz, 13C at 125.8 MHz and 31P at 202.4 MHz) spectrom-
eters. Solution infrared spectra (CaF2 cell) were acquired
on a DigiLab Excalibur FTS-3000 spectrometer. Mass
spectra were acquired on a VG Autospec spectrometer
employing the Fast-Atom-Bombardment (FAB) tech-
nique. Elemental analyses were performed by Microana-
lytical Services, Research School of Chemistry,
Australian National University. Preparative Thin Layer
Chromatography was performed on glass plates
(20 ꢀ 20 cm) coated with Silica Gel (Fluka, 60GF254).
The ligand LH2 was prepared according to literature
procedures [21] and references therein.
2020w, 1998vs, 1976vs, 1940m cmꢂ1. H NMR (acetone-
1
d6) d 7.7–7.1 (m, Ph), 5.73 (m, 1JPH = 400 Hz, 3JHH is unre-
solved, PH), 5.05, 4.55 (m, 2H, l-dppm, unit B), 4.73 (br d,
2H, l-dppm, unit A), 2.35 (m, 2H, PCH2), 1.87 (m, 2H,
2
3
SCH2), ꢂ14.95 (dd, 1H, JPH = 33, JPH = 3.4 Hz, RuH),
ꢂ14.98 (dd, 1H, JPH = 33, JPH = 3.4 Hz, RuH). 31P
2
3
2
NMR (acetone-d6) d 20.52 (d, JPP = 44 Hz, dppm, Unit
2
A), 20.33 (d, JPP = 44 Hz, dppm, Unit A), 16.24 (d,
2JPP = 44 Hz, dppm, Unit A), 16.1 (m, dppm, Unit B),
2
15.82 (d, JPP = 44 Hz, dppm, Unit A), ꢂ3.10 (t, J ca.
11 Hz, PH), ꢂ4.09 (t, ca. 11 Hz, PH). FABMS (NOBA)
m/z 2020, [M+].
2.1.2. Preparation of [Ru4(CO)10(SCH2CH2PPh)2] (4)
To a solution of [Ru3(CO)12] (100 mg, 0.16 mmol) in
THF (80 mL) was added LH2 (22 lL, 0.56 mmol) and five

1740
L.T. Byrne et al. / Journal of Organometallic Chemistry 693 (2008) 1738–1750
drops of a sodium benzophenone ketyl solution. The
resulting solution was stirred for 13 h and the solvent was
removed in vacuo and the residue chromatographed
(TLC, 30:70; acetone–hexanes). The only tractable and
major red band (Rf 0.76) was collected and crystallised
from CH2Cl2/hexanes giving red needles of 4 (24 mg,
22%). Anal. Calc. for C26H18O10P2Ru4S2: C, 30.59; H,
1.78. Found: C, 30.99; H, 1.42%. IR (CH2Cl2): m(CO)
2088w, 2049s, 2011s, 1993sh, 1978sh. FABMS (NOBA)
m/z 1023, [M+].
t(CO) 2035s, 2021s, 1987w, 1968s, 1937sh. FABMS
(NOBA) m/z 1068, [M+].
2.2. Structure determinations
For 2, 3, 6, 7, full spheres of CCD area-detector diffrac-
tometer data were measured (Bruker AXS instrument, x-
˚
˚
scans; monochromatic Mo Ka radiation, k = 0.71073 A;
T ca. 153 K); for 4, synchrotron radiation (k = 0.5594 A)
was employed (T ca. 110 K). N(total) reflections were
obtained, these merging to N unique (Rint cited) after
‘empirical’/multiscan absorption correction (proprietary
software), No with F > 4r(F) considered ‘observed’. Full
matrix least squares refinements on all data, refined aniso-
tropic displacement parameter forms for the non-hydrogen
2.1.3. Preparation of [RuCo(CO)6(SCH2CH2AsMe
(C6H4CH2 OMe))] (5)
A
solution of HSCH2CH2AsMe(C6H4CH2OMe)
(73 mg, 0.27 mmol) in hexane (10 mL) was added to a solu-
tion of [RuCo2(CO)11] (151 mg, 0.29 mmol) in hexane
(20 mL) dropwise by cannula, dissipating the initial red col-
our. After standing at room temperature overnight the
brown-yellow suspension was filtered by cannula, concen-
trated in vacuo and stored at low temperature (ꢂ22 °C)
to afford brown crystals of 5 (52 mg, 30%). Anal. Calc.
for C17H16AsCoO7RuS: C, 34.07; H, 2.69. Found: C,
atoms, (x,y,z,Uiso H being included following a riding
)
model; reflection weights were (r2(F) + (aP)2 + bP)ꢂ1
(P = F2o + 2F2c/3). For 5, a unique, single-counter diffrac-
tometer data set was measured; T was 295 K. Neutral atom
complex scattering factors were employed within the con-
text of the SHELX 97 program [22]. Pertinent results are
given below and in the tables and figures, the latter show-
ing 50% probability amplitude displacement envelopes for
the non-hydrogen atoms. Individual variations in proce-
dure are noted as ‘variata’.
1
33.86; H, 2.47%. M.p. >150 °C (dec). H NMR d (d6-ben-
zene) 1.38 (s, 3H, AsCH3); 1.62, 1.85, 2.05, 2.50 (m, 4H,
AsCH2 CH2S); 3.04 (s, 3H, OCH3); 4.08 (AB pattern,
2H, JAB = 12 Hz, CH2OCH3); 6.59, 6.81, 6.95, 7.03 (m,
4H, C6H4) 13C NMR d (d6-benzene) 13.2 (AsCH3), 29.3
(AsCH2CH2S), 32.7 (AsCH2CH2S), 58.0 (OCH3), 130.9,
130.3, 136.3, 139.9 (Ph), 189.0, 192.7, 200.2, 208.8 (M-
CO). FAB-MS (NOBA) 600, [M+], 100; 572–488,
[M+ꢂnCO].
2.2.1. Variata
3: Phenyl ring 52n was modelled as disordered over two
sets of sites, occupancies refining to 0.66(1) and comple-
ment (isotropic displacement parameters for the minor C6
component). The core hydride atoms were located by
refinement in (x,y,z,Uiso)H.
2.1.4. Preparation of [Ru3(CO)5(l-dppm)(PMe
(C6H4CH2OMe))4] (6) and [Ru3H(CO)7(l-dppm)
(P(@O) Me(C6H4CH2OMe))] (7)
4: A number of significant difference map residues
(<3 e Aꢂ3) were observed in the vicinity of the ruthenium
˚
core, not susceptible of sensible modelling and suggestive
of core disorder or cocrystallized minor impurity.
5: Material was badly twinned; overlapping reflections
were refined as a separately scaled group.
6: Solvent residues were modelled in terms of disordered
CH2Cl2 (site occupancies for one molecule disordered over
two sites, set at 0.5 with the other, also disordered over
three sites, set at 0.33) with idealised geometries. Methoxyl
groups 412, 512, 612 were modelled as disordered over
pairs of sites, occupancies set at 0.5 after trial refinement,
ring 51n being similarly disordered.
A
solution of [Ru3(l-dppm)(CO)10] (1) (100 mg,
0.10 mmol) in THF was treated with HPMe(C6H4-
CH2OMe) (16 ll, 0.10 mmol) and heated to reflux for
7 h. The resulting dark red solution was evaporated to dry-
ness and attempted crystallisation of the residue from
CH2Cl2/hexanes gave a small amount of 6 overnight
(19 mg, 13%). Anal. Calc. for C66H70O9P6Ru3: C, 52.98;
H, 4.72. Found: C, 51.14; H, 4.65%. IR (CH2Cl2): m(CO)
2008w, 1977s, 1944w, 1919s, 1909sh. FABMS (NOBA)
m/z 1499, [M+].
The supernatant was subjected to preparative TLC giv-
ing four bands (Rf 0.66, red; Rf 0.59, yellow; Rf 0.51, red; Rf
0.44, yellow) and significant decomposition. None of these
bands gave appreciable material on work-up.
7: Solvent CH2Cl2 was modelled as disordered about a
crystallographic inversion centre.
3. Results and discussion
In a another reaction analogous to the one above, a
solution of [Ru3(l-dppm)(CO)10] (1) (200 mg, 0.21 mmol)
in THF was treated with an excess of HPMe(C6H4-
CH2OMe) {presumably contaminated with HP(@O)
Me(C6H4CH2OMe)} (128 ll, 0.83 mmol). Crystallisation
of the dark residue obtained from the reaction gave a small
amount of 7 (49 mg, 22%). Anal. Calc. for C41H35O9P3Ru3:
C, 46.12; H, 3.30. Found: C, 45.63; H, 2.67%. IR (CH2Cl2):
The substituted ruthenium carbonyl cluster 1 is reactive
and well known to undergo substitution reactions with
phosphine ligands [15]. In addition, simple thiols, such as
PhSH, are known to add across a Ru–Ru bond [23]. In
the former case the P donor substitutes an equatorial
CO, whereas the latter gives the thiolato hydrido cluster
in which the bridging H and SPh ligands span the same

L.T. Byrne et al. / Journal of Organometallic Chemistry 693 (2008) 1738–1750
1741
Scheme 1.
Ru–Ru bond. The 2-(phenylphosphine)ethanethiol ligand,
HPPhCH2CH2SH (@ LH2), has additional functionality
in the form of a secondary phosphine and it was of interest
to observe the mode of reaction with 1 in light of this sur-
feit of functionality. When the reaction occured at the tem-
perature of refluxing toluene a large number of intractable
products were formed. Under ambient conditions the reac-
tion was very slow and in some cases considerable decom-
position was also observed. However, the reaction of LH2
with 1 in toluene at 60 °C presented a mixture of three com-
plexes on work up by TLC, Scheme 1. There was an appre-
ciable amount of residual starting material returned and
two new products, which were characterised by microanal-
ysis, standard spectroscopic techniques, and by single-crys-
tal X-ray diffraction studies as 2 and 3. When the reaction
was carried out with an excess of ligand present, a number
of products were isolated but none of these corresponded
to 2 or 3 and they are yet to be identified. Activating the
cluster to substitution utilising sodium benzophenone ketyl
radical did not improve the yields of 2 or 3 nor did per-
forming the reaction overnight at 60 °C.
The IR spectra of the complexes 2 and 3 contained
bands that are consistent with terminal CO ligands and
their FAB mass spectra contained molecular ions which
lost consecutive CO ligands in the case of complex 2.
The two complexes gave complicated NMR spectra con-
sistent with the presence of the stereogenic centres in the
molecules. The presence of metal bound hydrides was
inferred from the upfield resonances found in proton
NMR spectra.
Table 1
Selected geometries (2)
Atoms
Parameter
Atoms
Parameter
˚
Distances (A)
Ru(1)–Ru(2)
Ru(1)–Ru(3)
Ru(2)–Ru(3)
Ru(1)–C(11)
Ru(1)–C(12)
Ru(1)–C(13)
Ru(2)–H
2.8446(3)
2.8191(3)
2.8712(3)
1.924(2)
1.940(2)
1.899(3)
1.65(4)
Ru(1)–P(1)
Ru(2)–P(2)
Ru(2)–C(21)
Ru(2)–C(22)
Ru(2)–S(1)
Ru(3)–S(1)
Ru(3)–C(31)
Ru(3)–C(32)
Ru(3)–P(4)
2.3176(6)
2.3167(6)
1.879(2)
1.902(3)
2.4040(6)
2.3875(6)
1.889(2)
1.874(3)
2.3064(7)
Ru(3)–H
1.77(4)
Angles (°)
Ru(2)–Ru(1)–Ru(3)
Ru(1)–Ru(2)–Ru(3)
Ru(1)–Ru(3)–Ru(2)
P(1)–Ru(1)–Ru(2)
P(1)–Ru(1)–Ru(3)
Ru(1)–Ru(3)–P(4)
Ru(1)–Ru(3)–S(1)
Ru(2)–Ru(3)–P(4)
Ru(2)–Ru(3)–S(1)
60.921(8)
59.101(7)
59.978(6)
95.00(2)
155.89(2)
163.93(2)
81.71(2)
P(2)–Ru(2)–Ru(1)
P(2)–Ru(2)–Ru(3)
P(2)–Ru(2)–S(1)
Ru(1)–Ru(2)–S(1)
Ru(3)–Ru(2)–S(1)
Ru(2)–S(1)–Ru(3)
Ru(2)–S(1)–C(2)
Ru(3)–S(1)–C(2)
S(1)–Ru(3)–P(4)
Ru(3)–P(4)–C(3)
85.35(2)
136.11(2)
100.11(2)
80.90(2)
52.92(2)
73.63(2)
109.99(9)
106.27(8)
83.92(2)
107.28(8)
105.34(2)
53.45(2)
Fig. 1. Molecular projection of the structure of 2.

1742
L.T. Byrne et al. / Journal of Organometallic Chemistry 693 (2008) 1738–1750
The NMR spectra measured for 3 suggested the pres-
in the diastereoisomers. The other two overlapping dou-
blets of doublets observed at d ꢂ3.10 and ꢂ4.09 ppm
(3JPP ca. 10 Hz, ca. 11 Hz), significantly downfield of the
free ligand [21], are assigned to the diastereomeric PH moi-
eties of the phenylphosphinoethanethiol ligand, on the
basis of the proton-coupled 31P NMR spectrum which
ence of isomeric, presumably diastereomeric, species in
equal ratio. The 31P{1H} NMR spectrum measured for
complex 3 clearly illustrates this point as it contains two
essentially identical, in some parts overlapping, sets of res-
onances. In recent work we have unequivocally assigned
the 31P{1H} NMR spectra of [Ru3(CO)9(dppm)(PR3)]
[15] complexes which are analogous to segment B of com-
plex 3 while segment A observes close similarity to the
well–known sulfido clusters [Ru3(l–H)(l–SR)(CO)8
(dppm)] [23]. Thus, the complex multiplet centered at ca.
16.0 ppm in the 31P{1H} NMR spectrum of 3 is assigned
to the l–dppm of unit B. Signals attributable to the analo-
gous bidentate ligand of unit A are partly obscured by this
resonance but the doublets at d 20.52, 20.33, 16.24 and
1
showed a JPH = 348 Hz for each of these resonances.
These signals are coupled to the P atoms of the l-dppm
ligand of unit B with a coupling constant of ca. 11 Hz.
The presence of a metal hydride was inferred by the
presence of two doublets of doublets observed at ca.
3
ꢂ15 ppm (2JPH = 33.0; JPH = 3.4 Hz) in the 1H NMR
spectrum of 3 resulting from coupling to the two
inequivalent phosphorus atoms of unit A, each set of
doublet of doublets suggesting an equivalent mixture of
diastereoisomers. The primary phosphine PH resonance
is assigned to the complex multiplet centred on d 5.73
2
15.82 ppm, with characteristic JPP = 44 Hz [23], were
assigned to the inequivalent P atoms of the l-dppm ligand
Table 2
Selected geometries (3) (molecules 1 and 2)
Atoms
Distances (A)
Segment A (for counterpart Ru in molecule 2, read 7–9 for 1–3)
Parameter
Atoms
Parameter
˚
Ru(1)–Ru(2)
Ru(1)–Ru(3)
Ru(2)–Ru(3)
Ru(1)–P(1)
Ru(1)–C(11)
Ru(1)–C(12)
Ru(1)–C(13)
Ru(3)–H
2.8344(6), 2.8356(7)
2.8143(6), 2.8095(7)
2.8594(7), 2.8654(7)
2.322(1), 2.324(2)
1.921(6), 1.918(6)
1.932(5), 1.949(6)
1.899(6), 1.895(6)
1.68(7), 1.70(^)
Ru(2)–P(2)
Ru(2)–S(1)
Ru(2)–H
Ru(2)–C(21)
Ru(2)–C(22)
Ru(3)–S(1)
Ru(3)–C(31)
Ru(3)–C(32)
Ru(3)–C(33)
2.316(1), 2.314(2)
2.393(1), 2.387(1)
1.71(7), 1.86(6)
1.876(5), 1.874(6)
1.901(6), 1.904(6)
2.393(1), 2.389(2)
1.904(6), 1.894(7)
1.903(6), 1.888(7)
1.924(6), 1.914(7)
Segment B (for counterpart Ru in molecule 2, read 10–12 for 4–6)
Ru(4)–Ru(5)
Ru(4)–Ru(6)
Ru(5)–Ru(6)
Ru(4)–P(4)
Ru(4)–C(41)
Ru(4)–C(42)
Ru(4)–C(43)
2.8353(6), 2.8442(6)
2.8460(7), 2.8434(7)
2.8490(6), 2.8449(6)
2.326(1), 2.318(1)
1.932(5), 1.935(6)
1.927(5), 1.931(5)
1.888(5), 1.885(5)
Ru(5)–P(5)
Ru(5)–C(51)
Ru(5)–C(52)
Ru(5)–C(53)
Ru(6)–P(6)
Ru(6)–C(61)
Ru(6)–C(62)
Ru(6)–C(63)
2.325(2), 2.330(1)
1.931(5), 1.922(5)
1.919(6), 1.933(5)
1.889(5), 1.887(6)
2.308(1), 2.295(1)
1.932(5), 1.922(6)
1.924(5), 1.936(6)
1.890(5), 1.892(6)
Angles (°)
Segment A (n = 1,3)
Ru(2)–Ru(1)–Ru(3)
Ru(1)–Ru(2)–Ru(3)
Ru(2)–Ru(3)–Ru(1)
P(1)–Ru(1)–Ru(2)
P(1)–Ru(1)–Ru(3)
Ru(2)–S(1)–Ru(3)
Ru(2)–S(1)–C(2)
Ru(3)–S(1)–C(2)
60.82(2), 61.06(2)
59.24(1), 59.05(2)
59.94(2), 59.95(2)
93.81(3), 93.76(4)
154.61(4), 154.75(4)
73.38(4), 73.74(4)
107.6(2), 107.7(2)
108.4(2), 107.8(2)
Ru(1)–Ru(2)–P(2)
Ru(3)–Ru(2)–P(2)
S(1)–Ru(2)–Ru(1)
S(1)–Ru(2)–P(2)
S(1)–Ru(2)–Ru(3)
S(1)–Ru(3)–Ru(1)
S(1)–Ru(3)–Ru(2)
86.39(3), 86.47(4)
135.65(4), 135.99(4)
82.03(3), 80.99(4)
98.25(5), 98.42(5)
53.30(3), 53.16(4)
82.48(3), 81.50(4)
53.33(3), 53.10(3)
Segment B
Ru(5)–Ru(4)–Ru(6)
Ru(5)–Ru(4)–P(4)
Ru(6)–Ru(4)–P(4)
Ru(4)–Ru(6)–Ru(5)
P(6)–Ru(6)–Ru(4)
Ru(6)–P(6)–C(3)
Ru(6)–P(6)–C(611)
60.19(1), 60.02(2)
89.47(4), 93.73(4)
148.06(4), 150.49(4)
59.72(2), 60.00(2)
153.46(4), 156.90(6)
117.6(2), 115.4(2)
117.5(6), 115.8(2)
Ru(4)–Ru(5)–Ru(6)
Ru(4)–Ru(5)–P(5)
Ru(6)–Ru(5)–P(5)
P(6)–Ru(6)–Ru(5)
P(4)–C(20)–P(5)
60.09(2), 59.97(2)
94.60(4), 89.15(4)
152.86(4), 147.78(4)
97.65(4), 101.16(4)
115.9(3), 114.6(4)
104.5(2), 105.0(3)
C(3)–P(6)–C(611)

L.T. Byrne et al. / Journal of Organometallic Chemistry 693 (2008) 1738–1750
1743
1
with an apparent JPH = 400 Hz, more accurate assign-
although the angles at C(2,3) (115.2(2), 108.7(2)°) do not
appear greatly affected. The torsions in the chelate ring
bonds commencing at S(1)–C(2), C(2)–C(3) et seq.:
19.1(2)°, ꢂ42.4(3)°, 46.6(2)°, ꢂ27.6(1)°, 7.6(1)°, show
quasi-2 symmetry. As in 3, the associated Ru–Ru bond is
the longest, similar distances being observed in both com-
plexes. As in 3, the dppm ligand bridges Ru–Ru bond adja-
cent to (rather than containing) the S-bridge. Distances and
other geometrical features are similar in both compounds;
ment being hindered by the presence of longer range
couplings to other H and P nuclei. The remaining signals
confirm the presence of isomers and have been assigned
on the basis of comparison to compounds reported in
the literature [15,21,23].
The 1H and 31P{1H} NMR spectra of compound 2 were
similarly complex. In these spectra it was clear that two,
closely related complexes were present (2:1 ratio), presum-
ably diastereoisomers, but one was in the majority com-
˚
here P(1,2,4)S lie ꢂ0.044(2), 1.047(2), 0.275(2), 1.870(1) A
1
pared to the other. The feature of most interest in the H
out of the Ru3 plane. An interesting feature of both struc-
tures is some apparent/possible displacement of the core
hydride toward the ruthenium distant from the dppm
chelate.
NMR spectrum of 2 were the signals associated with the
phenylphosphino moiety. The major isomer showed only
a 1JPH coupling while the minor isomer displayed this cou-
pling as well as smaller couplings to other nuclei as yet
undetermined, most likely distant P or H atoms. The origin
of this phenomenon is unclear but it has been shown that
even small geometrical variations about P nuclei can vastly
affect 31P chemical parameters. The remaining signals were
assigned with the aid of an 1H–31P HMBC experiment and
clearly showed the presence of the isomers.
Compound 2 crystallizes unsolvated with one formula
unit, devoid of crystallographic symmetry, comprising the
asymmetric unit of the structure, confirming the stoichiom-
etry, connectivity, and stereochemistry as given above (see
Table 1, Fig. 1). The present compound may be contrasted
with compound 3 in respect of the presence of one, and
one-half ligand, LH, per Ru3 cluster. In 2 the ligand L acts
as a chelate; in 3 it bridges two clusters. In both cases, the
two donors differ in their mode of coordination, P coordi-
nating equatorially in the cluster, directly to a ruthenium
atom, S behaving as a bridge, with the two Ru–S distances
symmetrical/equivalent in both cases, perhaps surprisingly
so in the present where 2 involved as a chelate to the one
atom, ring strain might constitute a significant influence,
Compound 3 crystallizes as an acetone monosolvate,
two formula units, devoid of crystallographic symmetry,
comprising the asymmetric unit of the structure, confirm-
ing the stoichiometry, stereochemistry and connectivity to
be as given above (Table 2, Fig. 2). The two molecules
are very similar in respect of conformation; each is com-
prised of a pair of components (units A and B, Scheme
1) based on the familiar Ru3 unit and linked by the
extended ligand L. Unit B comprises a ruthenium carbonyl
basis with two of the ruthenium atoms bridged equatorially
by P-dppm-P0 in conventional manner; the third ruthenium
is coordinated equatorially by the phosphorus of the P,S-
ligand at a barely shorter distance; the chelating phospho-
rus atoms lie ꢂ0.424(3), 0.417(3) (molecule 1); ꢂ0.572(3),
˚
0.390(3) A (molecule 2) out of the Ru3 plane, the deviations
˚
of the pendant phosphorus being 0.584(3); 0.561(3) A.
˚
Ruꢁ ꢁ ꢁRu distances are all very similar (>2.844(5) A). In
units A one side of the triangle (Ru(n2)–Ru(n3)) is bridged
by both hydride and sulfur donors to either side of the
plane, Ru(n2) and Ru(n1) being chelated by the P-dppm-
0
˚
P units. S lie 1.862(2), 1.864(2) A out of plane, with
Fig. 2. Molecular projection of one of the formula units in the structure of 3. (Unit A on the right, B on the left).

1744
L.T. Byrne et al. / Journal of Organometallic Chemistry 693 (2008) 1738–1750
P(n1, n2) deviant by ꢂ0.040(3), 1.136(2); ꢂ0.043(3),
SCH2CH2PPh)2], 4, (Chart 1). In this case the phen-
ylphosphino component of LH2 has been deprotonated
and is manifested as a bridging phosphido ligand and the
thiol also adopts a bridging mode; in both cases the hydro-
gen attached to the heteroatom was lost. As a consequence
of insolubility we were unable to obtain any spectroscopic
data on the complex. In fact, the size of the crystals
obtained after multiple attempts at crystallisation necessi-
tated the collection of data for the single crystal study at
a synchrotron.
˚
1.106(2) A (molecules 1 and 2); the skewing of P(n2)/
CO(n21) relative to the Ru3 plane is much less than that
of CO(n31/n32), presumably in consequence of the chelate
constraint.
The thermally activated reaction of [Ru3(CO)12] with
LH2, resulted in total decomposition. However, the
analogous radical initiated reaction gave only one tractable
product after chromatography, which was identified on the
basis of a single crystal X-ray study as [Ru4(CO)10(l2:l2-
Compound 4 crystallizes unsolvated with two indepen-
dent neutral molecules, devoid of crystallographic symme-
try, comprising the asymmetric unit of the structure,
confirming the stoichiometry, connectivity and stereochem-
istry as given above (see also Fig. 3, Table 3). Despite the
above comments, the molecular symmetry is close to 2,
although across equivalent parameters between the (four)
possibilities, individual excursions from their mean may
be substantial. The core of each molecule is an Ru4 ‘butter-
fly’, the fold angles across Ru(n1)–Ru(n2) being 139.38(4)°
and 138.28(4)°. Within the pair of Ru3 planes so defined,
the distances are dissimilar within each plane, the bond
not fusing the two planes or bridged by the P,S-ligand
the longest, and the fusing bond the shortest. The interme-
diate bond is straddled by the chelate, L, both S- and P-
donors bridging the two ruthenium atoms l2 and lying to
either side of the associated Ru3 plane. The SCCP string
is essentially planar, with the two associated Ru atoms
Chart 1.
Fig. 3. Molecular projection of one of the formula units in the structure of 4.

L.T. Byrne et al. / Journal of Organometallic Chemistry 693 (2008) 1738–1750
1745
˚
lying to either side. Interestingly, the phenyl groups pen-
dant from the phosphorus atoms are quasi-coplanar with
the ‘C2SP’ planes, despite close approaches between one
of the ortho hydrogen atoms H(nm12) and the adjacent
the closest such contact (H(2116)ꢁ ꢁ ꢁO(221)) is 2.65 A (est.).
Among the carbonyl groups, there is little difference
between the Ru–C distances for the pairs on the ‘fold’
Ru atoms; at the peripheral atoms Ru–C(CO) are longer,
with the distance to the carbonyl lying adjacent to the sul-
fur the longest of all. There are a number of examples of
this type of cluster in the literature, two salient examples
being [Ru4(l4-k4-dmpu)(CO)10], (H2dmpu = N,N0-bis(6-
methylpyrid-2-yl)urea) [24] and [Ru4(CO)13(l-PPh2)2] and
[Ru4(CO)10(l-PPh2)4] [25].
˚
methylene hydrogen, in all cases ca. 2.3–2.4 A (est.), and
despite the C–P–C angle being less than the tetrahedral
value; Ru–P–C (phenyl) in all cases are very large,
123.8(2)–127.9(2)°. The other ortho hydrogen is directed
toward the alternate carbonyl oxygen of the pair of carbon-
yls which lie beneath the fold, with an appreciable torsion;
Table 3
Selected geometries (4) (molecules 1 and 2)
Atoms
Parameter
Atoms
Parameter
< >
˚
Distances (A) (in molecule 2 read 1–4 as counterparts 5–8)
Ru(1)–Ru(2)
Ru(1)–Ru(3)
Ru(1)–Ru(4)
Ru(1)–S(1)
Ru(1)–P(1)
Ru(3)–S(1)
Ru(3)–P(1)
Ru(1)–C(11)
Ru(1)–C(12)
Ru(3)–C(33)
Ru(3)–C(31)
Ru(3)–C(32)
2.877(1), 2.856(1)
2.914(1), 2.973(1)
3.042(1), 3.007(1)
2.396(2), 2.417(2)
2.275(2), 2.255(2)
2.408(2), 2.399(2)
2.349(2), 2.332(2)
1.880(6), 1.875(6)
1.863(6), 1.880(6)
1.921(6), 1.909(6)
1.917(6), 1.927(6)
1.948(6), 1.970(6)
2.867(13)
2.95(3)
3.02(2)
Ru(2)–Ru(4)
Ru(2)–Ru(3)
Ru(2)–S(2)
Ru(2)–P(2)
Ru(4)–S(2)
Ru(4)–P(2)
Ru(2)–C(21)
Ru(2)–C(22)
Ru(4)–C(43)
Ru(4)–C(41)
Ru(4)–C(42)
2.966(1), 2.931(1)
3.012(1), 3.026(1)
2.412(1), 2.411(2)
2.256(2), 2.270(2)
2.387(2), 2.407(2)
2.353(2), 2.344(2)
1.885(6), 1.880(6)
1.880(6), 1.880(6)
1.907(6), 1.909(6)
1.908(7), 1.918(6)
1.957(6), 1.959(6)
2.409(9)
2.263(9)
2.399(11)
2.344(9)
1.879(8)
1.883(11)
1.912(10)
1.918(15)
1.964(14)
Angles (°)
Ru(2)–Ru(1)–Ru(3)
Ru(2)–Ru(1)–Ru(4)
Ru(2)–Ru(1)–S(1)
Ru(2)–Ru(1)–P(1)
Ru(3)–Ru(1)–Ru(4)
Ru(3)–Ru(1)–S(1)
Ru(3)–Ru(1)–P(1)
Ru(4)–Ru(1)–S(1)
Ru(4)–Ru(1)–P(1)
S(1)–Ru(1)–P(1)
Ru(1)–Ru(3)–Ru(2)
Ru(1)–Ru(3)–S(1)
Ru(1)–Ru(3)–P(1)
Ru(2)–Ru(3)–S(1)
Ru(2)–Ru(3)–P(1)
S(1)–Ru(3)–P(1)
Ru(1)–S(1)–Ru(3)
Ru(1)–S(1)–C(102)
Ru(3)–S(1)–C(102)
Ru(1)–P(1)–Ru(3)
Ru(1)–P(1)–C(101)
Ru(3)–P(1)–C(101)
C(111)–P(1)–C(101)
Ru(1)–P(1)–C(111)
Ru(3)–P(1)–C(111)
62.67(2), 62.51(2)
60.06(2), 59.92(2)
89.34(4), 89.49(4)
108.33(4). 105.74(5)
110.81(3), 109.96(3)
52.84(4), 51.68(4)
52.06(4), 50.78(4)
91.20(4), 91.77(4)
162.21(5), 160.59(5)
74.50(5), 74.18(5)
58.06(2), 56.85(2)
52.47(4), 52.14(4)
49.82(4), 48.48(4)
86.00(4), 85.90(4)
102.17(4), 98.70(4)
72.99(5), 73.15(5)
74.70(4), 76.26(4)
101.5(2), 101.7(2)
104.7(2), 101.9(2)
78.12(5), 80.74(5)
108.5(2), 108.3(2)
106.5(2), 106.2(2)
105.7(3), 107.7(3)
127.9(2), 126.9(2)
126.8(2), 123.8(2)
Ru(1)–Ru(2)–Ru(4)
Ru(1)–Ru(2)–Ru(3)
Ru(1)–Ru(2)–S(2)
Ru(1)–Ru(2)–P(2)
Ru(4)–Ru(2)–Ru(3)
Ru(4)–Ru(2)–S(2)
Ru(4)–Ru(2)–P(2)
Ru(3)–Ru(2)–S(2)
Ru(3)–Ru(2)–P(2)
S(1)–Ru(2)–P(2)
Ru(2)–Ru(4)–Ru(1)
Ru(2)–Ru(4)–S(2)
Ru(2)–Ru(4)–P(2)
Ru(1)–Ru(4)–S(2)
Ru(1)–Ru(4)–P(2)
S(2)–Ru(4)–P(2)
Ru(2)–S(2)–Ru(4)
Ru(2)–S(2)–C(202)
Ru(4)–S(2)–C(202)
Ru(2)–P(2)–Ru(4)
Ru(2)–P(2)–C(201)
Ru(4)–P(2)–C(201)
C(211)–P(2)–C(201)
Ru(2)–P(2)–C(211)
Ru(4)–P(2)–C(111)
62.74(2), 62.60(2)
59.27(2), 60.64(2)
88.93(4), 89.03(5)
107.19(5), 107.92(5)
110.24(2), 110.61(3)
51.44(4), 52.46(4)
51.41(5), 51.68(4)
92.15(4), 90.34(4)
161.43(5), 161.38(5)
74.01(5), 74.13(5)
57.20(2), 57.48(2)
52.24(3), 52.61(4)
48.52(4), 49.45(4)
85.60(4), 85.66(4)
99.67(4), 101.30(4)
72.79(5), 72.93(5)
76.32(5), 74.94(4)
102.2(2), 101.0(2)
102.5(2), 104.7(3)
80.07(6), 78.87(5)
108.2(2), 108.4(2)
106.5(3), 106.6(2)
106.7(3), 106.3(3)
125.6(2), 127.5(2)
126.7(2), 126.0(2)
62.64(10)
60.0(6)
89.2(3)
107.3(12)
110.4(4)
52.1(7)
51.5(6)
91.4(8)
161.4(7)
74.2(2)
57.4(5)
52.4(2)
49.1(7)
85.8(2)
100.5(15)
72.96(14)
75.6(9)
101.8(4)
104(2)
79.5(12)
108.2(4)
106.6(3)
106.5(10)
127.1(10)
125.9(15)
Torsion angles (°)(carbon atoms denoted by number only)
Ru(1)–S(1)–102–101
S(1)–102–101–P(21)
Ru(1)–P(21)–101–102
101–P(1)–111–112
11–Ru(1)–Ru(2)–21
42.7(5), 38.0(5)
Ru(2)–S(2)–202–201
36.7(5), 43.0(4)
ꢂ5.9(5), ꢂ0.3(6)
ꢂ36.9(4), ꢂ42.3(5)
ꢂ8.2(6), ꢂ6.9(6)
ꢂ30.7(2), ꢂ29.5(2)
S(2)–202–201–P(2)
Ru(2)–P(2)–201–202
201–P(2)–211–212
1.3(6), ꢂ6.0(5)
ꢂ43.5(5), ꢂ37.7(5)
8.4(7), ꢂ3.4(5)
S(1)–Ru(1)–Ru(2)–S(2)
ꢂ45.52(5), ꢂ45.01(5)
˚
Out-of-plane deviations (d, A)
dS(1)(Ru3)
ꢂ1.770(2), 1.736(2)
0.940(2), ꢂ1.001(3)
dS(2)(Ru3)
dP(2)(Ru3)
ꢂ1.743(2), 1.773(2)
0.967(2), ꢂ0.934(2)
dP(1)(Ru3)

1746
L.T. Byrne et al. / Journal of Organometallic Chemistry 693 (2008) 1738–1750
The heterobimetallic cluster [RuCo2(CO)11] has a well
Compound 5 crystallizes unsolvated with one neutral
molecule, devoid of crystallographic symmetry, in the
asymmetric unit. The determination, somewhat imprecise,
by virtue of twinning problems, confirms the stoichiometry,
connectivity and stereochemistry as given above and in
Fig. 4 and Table 4. A search of the Cambridge Structural
Database [30] found no structurally characterised Ru–Co
dimers of this type. However one complex has some rele-
vant elements that can be considered, [(l3-S)RuCo2-
(CO)8(PMe2Ph)] [31]. This complex is trimetallic with a
l3-sulfide ligand, not strictly comparable to 5. The two
developed chemistry [26–29]. The existence of several differ-
ent metal atoms in a metal cluster provides many potential
structural and chemical opportunities for multisite binding
and catalysis of organic substrates or fragments on a metal
particle. The reaction between [RuCo2(CO)11] and
HSCH2CH2AsMe(C6H4CH2OMe) gave an extremely air-
sensitive solution from which a low yield of [RuCo-
(CO)6(l2:g1-SCH2CH2AsMe(C6H4CH2OMe))] (5) was
obtained. This was characterised by the use of standard
spectroscopic techniques. The complex gave a molecular
ion in the FAB mass spectrum consistent with the sequen-
tial loss of carbonyl ligands. The presence of stereogenic As
and S centres, with even framework chirality gave a com-
˚
Ru–Co bonds in [(l3-S)RuCo2(CO)8(PMe2Ph)] (2.666 A
(< >)) are not non-trivially different to the Ru–Co bond
˚
(2.689(2) A) in 5. While the Ru–S bond in 5 of 2.354(2) is
1
plex H NMR spectrum, albeit without the complication
only marginally different from that found in the trimetallic
complex, 2.364(2), with similar in significant differences are
seen in the Co–S distance: 2.203(3) in 5 and 2.173(3);
of coupling to the donor atom, which was assigned on
chemical shift data. The methylene protons of the arsino-
ethanethiol ligand gave a series of unresolved multiplets
between 1.6 and 2.50 ppm each integrating for one proton.
The signal at 1.38 ppm was assigned to the AsMe group,
while the signal at 4.08 ppm was assigned to the benzylic
protons giving the expected AB pattern. The down-field
singlet at 3.04 ppm was assigned to the methoxy protons.
The 13C NMR spectrum was similarly informative,
assigned with the aid of DEPT experiments, with the sig-
nals at 13.2 and 58.0 ppm assigned to the AsMe and
OMe moieties, respectively. The signals assigned to the
phenyl carbons were partly obscured by solvent peaks
but those of the metal-bound carbonyls are assigned to
the four separate signals in the usual region, ca. 190–
210 ppm.
˚
2.202(3) A in [(l3-S)RuCo2(CO)8(PMe2Ph)].
The reaction of [Ru3(l-dppm)(CO)10] with the second-
ary phosphine HPMe(C6H4CH2OMe) gave, on one
occasion, the trinuclear cluster [Ru3(CO)5(dppm)
(PMe(C6H4CH2OMe)) 4] (6), and on another occasion
the oxide cluster [Ru3H(CO)7(dppm)(l2, g1-P(@O)Me-
(C6H4CH2OMe))] (7). It appears that the highly air-sensi-
tive phosphine had a appreciable amount of the P(V) oxide
present, as evident from the number of impurities detected
by 31P NMR of the remaining ligand. This serendipitous
event has allowed us to examine the effect of coordination
of the phosphine oxides to metals. The complexes proved
too insoluble to obtain meaningful NMR data although
giving adequate microanalyses.
Compound 6 crystallizes with one neutral molecule,
devoid of crystallographic symmetry in the asymmetric
unit of the structure, together with residues modelling as
a dichloromethane disolvate; the latter are rife with disor-
der, also found throughout the phenyl ring 51 and more
widely among diverse methoxyl pendants, although site
occupancies, 0.5 throughout these latter, seemingly differ
from those of the solvent components (ca. 1/3) and may
not be concerted. The molecular core is well-defined, con-
forming the stoichiometry, connectivity and stereochemis-
try proposed above (see Table 5, Fig. 5). The molecule
comprises an open Ru3 triangle, Ru(1)ꢁ ꢁ ꢁRu(2) 3.8890(5)
0
˚
A, Ru(1,2) bridged by the P-dppm-P ligand, seemingly
Table 4
Selected geometries (5)
Atoms
Parameter
Atoms
Parameter
˚
Distances (A)
Ru(1)–Co(2)
Ru(1)–S(1)
2.689(2)
2.354(2)
Co(2)–S(1)
Ru(1)–As(1)
2.203(3)
2.461(1)
Angles (°)
Ru(1)–Co(2)–S(1)
Co(2)–S(1)–Ru(1)
Ru(1)–S(1)–C(103)
Co(2)–S(1)–C(103)
56.48(7)
72.25(8)
106.7(3)
112.6(3)
Co(2)–Ru(1)–S(1)
Co(2)–Ru(1)–As(1)
S(1)–Ru(1)–As(1)
51.27(7)
87.98(5)
86.03(7)
Fig. 4. Molecular projection of the structure of 5.

L.T. Byrne et al. / Journal of Organometallic Chemistry 693 (2008) 1738–1750
1747
Table 5
Selected geometries (6)
[(dppm){Ru(CO)2(l-P)2}2Ru] core has putative m symme-
try, broken at the molecular periphery by the dispositions
of the phosphorus substituents, most notably by the differ-
ing methyl dispositions at P(3,5), that at P(3), being ‘axial’,
while that at P(5) is ‘equatorial’, perhaps a consequence of
the general crowding at the Ru(3) end of the molecule. All
phosphorus atoms, except P(3,5) lie well above the Ru3
plane. Axial and equatorial Ru–C (carbonyl) distances
about Ru(1,2) differ systematically and significantly.
The overall structure adopted by [Ru3(CO)5(dppm)(l2-
PMe(C6H4CH2OMe))4] (6), appears to be unique with no
examples of a trinuclear, open-triangular cluster that con-
tains six phosphine/phosphide donors found in the CSD
[30]. The individual phosphides bridge the metal–metal
bonds, a motif that is well known in the literature [32–
40]. Much more common is a motif in which a triruthenium
cluster has each Ru–Ru vector symmetrically bridged by
phosphides, as exemplified by [Ru3(CO)9(l-H)(l-
P(C6H11)2)3] [38].
Atoms
Parameter
Atoms
Parameter
˚
Distances (A)
Ru(1)–Ru(3)
Ru(1)–P(1)
Ru(1)–P(5)
Ru(1)–P(6)
Ru(1)–C(11)
Ru(1)–C(12)
Ru(3)–P(6)
Ru(3)–P(5)
Ru(3)–C(31)
2.9394(5)
2.3892(7)
2.3473(8)
2.3758(7)
1.921(3)
1.851(3)
2.3700(8)
2.3376(8)
1.834(3)
Ru(2)–Ru(3)
Ru(2)–P(2)
Ru(2)–P(3)
Ru(2)–P(4)
Ru(2)–C(21)
Ru(2)–C(22)
Ru(3)–P(4)
Ru(3)–P(3)
Ru(1)ꢁ ꢁ ꢁRu(2)
2.9716(5)
2.3961(7)
2.3632(7)
2.4049(7)
1.916(3)
1.855(3)
2.3625(7)
2.3334(8)
3.8890(5)
Angles (°)
Ru(1)–Ru(3)–Ru(2)
C(0)–P(1)–Ru(1)
P(1)–Ru(1)–Ru(3)
P(1)–Ru(1)–P(6)
P(1)–Ru(1)–P(5)
P(1)–Ru(1)–C(12)
Ru(1)–P(6)–Ru(3)
Ru(1)–P(5)–Ru(3)
P(5)–Ru(1)–P(6)
P(5)–Ru(3)–P(6)
82.28(1)
124.9(2)
117.70(2)
96.88(3)
168.29(3)
93.05(9)
76.54(2)
77.72(2)
78.15(3)
78.51(3)
P(1)–C(0)–P(2)
121.7(2)
119.57(8)
116.04(3)
99.61(2)
163.57(7)
94.43(8)
77.11(2)
78.50(2)
78.50(3)
79.96(3)
C(0)–P(2)–Ru(2)
P(2)–Ru(2)–Ru(3)
P(2)–Ru(2)–P(4)
P(2)–Ru(2)–P(3)
P(2)–Ru(2)–C(22)
Ru(2)–P(4)–Ru(3)
Ru(2)–P(3)–Ru(3)
P(4)–Ru(2)–P(3)
P(4)–Ru(3)–P(3)
Compound 7 crystallizes with one neutral molecule,
devoid of crystallographic symmetry, comprising the asym-
metric unit of the structure together with an accompanying
CH2Cl2 hemi-solvate molecule which lies disordered about
a crystallographic inversion centre, consistent with the stoi-
chiometry, connectivity and stereochemistry as given above
(Table 6, Fig. 6). The molecular core is the familiar (l-
H)Ru3 array, chelated by P-dppm-P0 with the bridging core
hydride lying within the dppm chelate; the phosphine oxide
is coordinated with the oxygen spanning the hydrido/dppm
bridged ruthenium atoms, to the opposite site of the Ru3
Deviations of P(n) from the Ru3 plane are (n = 1–6): 1.321(2), 1.812(2),
ꢂ1.688(1), 1.244(1), ꢂ1.227(1), 1.694(1) A.
˚
under some strain, since P–C–P is very large (121.7(3)°),
and Ru(3). The pairs of bonded ruthenium atoms are
bridged by pairs of PMeAr (Ar@MeOCH2C6H4) ligands;
all ruthenium atoms have their coordination spheres com-
pleted by equatorial carbonyl groups, together with further
axial groups in the case of Ru(1,2); the molecular
˚
plane to the hydride (dH, 0.92(3); dO(3) ca. ꢂ1.709(1) A)
Fig. 5. Molecular projection of the structure of 6.

1748
L.T. Byrne et al. / Journal of Organometallic Chemistry 693 (2008) 1738–1750
˚
Table 6
Selected geometries (7)
rial) distances at Ru3 are closely ranged (< 0.13 A); the
differences in the Ru–C (carbonyl) distances at Ru(1,2)
are substantial, Ru-(quasi-)equatorial being longer than
Atoms
Parameter
Atoms
Parameter
˚
˚
their (less crowded) axial counterparts by ca. 0.045 A.
Distances (A)
Ru(1)–Ru(2)
Ru(1)–Ru(3)
Ru(2)–Ru(3)
Ru(1)–O(3)
Ru(1)–P(1)
Ru(1)–C(11)
Ru(1)–C(12)
Ru(3)–C(31)
Ru(3)–P(3)
2.7623(2)
2.7656(2)
2.7842(2)
2.202(1)
2.3736(4)
1.843(2)
1.900(2)
1.922(2)
2.3311(5)
Ru(1)–H(0)
Ru(2)–H(0)
Ru(2)–O(3)
Ru(2)–P(2)
Ru(2)–C(21)
Ru(2)–C(22)
Ru(3)–C(32)
Ru(3)–C(33)
1.67(3)
1.79(3)
Ru–C–O are all greater than 176.9°, excepting Ru(1)–
C(12)–O(12) which is reduced to 172.6(2)°, perhaps in con-
sequence of the proximity of the phenyl substituent, but it
is notable that contacts are more obvious to other carbon-
yls. Table 7 summarizes the crystallographic/refinement
data for all the compounds studied.
2.198(1)
2.3742(4)
1.849(2)
1.891(2)
1.909(2)
1.915(2)
Phosphine oxides do not generally make good ligands
but are known to undergo reactions with oxophilic metals
[41]. There are few structurally characterised examples of
such complexes in the literature although the reaction of
[Ru3(CO)12] with Ph2P(O)CCBut has given the binuclear
example [Ru2(CO)6(l2:g2-CCBut)(l-Ph2P@O)] [42]. The
only example of coordination of a PO moiety in a similar
manner to that observed in 7 is found in [Ru3(CO)9(l-
P(OMe)3)] [43]. In this case the P(III) ligand has utilised
the oxygen lone pairs to participate in bonding and is pre-
sumably a thermolysis product of [Ru3(CO)11(P(OMe)3)]
which was also isolated in the reaction of [Ru3(CO)12] with
(MeO)2PN(Me)N(Me)P(OMe)2. However, it is unclear
whether 7 is the product of the reaction of 1 with the
P(V), compound HP(O)Me(C6H4CH2OMe) or the oxida-
tion of a pre-formed cluster containing a phosphide ligand.
What is known is that l3-P ligands can be oxidised, with
the PO thus formed retained in the structure [41] but it is
also known that 1 tends to add more than one secondary
Angles (°)
Ru(2)–Ru(1)–Ru(3)
Ru(2)–Ru(3)–Ru(1)
Ru(1)–P(1)–C(0)
P(1)–Ru(1)–Ru(2)
P(1)–Ru(1)–Ru(3)
P(1)–Ru(1)–O(3)
Ru(1)–O(3)–Ru(2)
Ru(1)–O(3)–P(3)
Ru(1)–H(0)–Ru(2)
60.486(5)
59.70(1)
108.32(5)
95.03(1)
153.77(1)
82.76(3)
77.79(4)
99.12(6)
106(1)
Ru(1)–Ru(2)–Ru(3)
P(1)–C(0)–P(2)
59.817(5)
114.98(8)
107.16(5)
93.31(1)
152.99(1)
87.07(3)
99.12(5)
98.68(6)
Ru(2)–P(2)–C(0)
P(2)–Ru(2)–Ru(1)
P(2)–Ru(2)–Ru(3)
P(2)–Ru(2)–O(3)
O(3)–P(3)–Ru(3)
Ru(2)–O(3)–P(3)
(the phosphorus atoms are also well out of plane, all to the
same side as O(3): dP(1,2,3) 0.416(2), 0.120(2) 2.127(1) A).
˚
The {(PP)HRu3(CO)7PO} molecular core has quasi-m
symmetry, broken by the unsymmetrical substitution at
P(3), and, peripherally, by the diverse phenyl orientations,
most impressively in the (dppm-)P–Ru–O angles which dif-
fer by more than 4°. The Ru–C (carbonyl) (axial/equato-
Fig. 6. Molecular projection of the structure of 7.

L.T. Byrne et al. / Journal of Organometallic Chemistry 693 (2008) 1738–1750
1749
Table 7
Crystal/refinement data
Compounds
2
3 ꢁ C2H6O
4
5
6 ꢁ 2CH2Cl2
7 ꢁ 1/2CH2Cl2
Formula
C40H33O7P3Ru3S
1053.9
Monoclinic
P21/c (No. 14)
15.579(1)
C78H61O18P5Ru6S
2079.7
Triclinic
C26H18O10P2Ru4S2
1020.8
Triclinic
C17H16AsCoO7RuS
599.3
Monoclinic
P21/c (No. 14)
9.077(8)
C68H74Cl4O9P6Ru3
1666.2
Triclinic
C41.5H36ClO9P3Ru3
1110.3
Triclinic
Mr (Dalton)
Crystal system
Space group
ꢀ
ꢀ
ꢀ
ꢀ
P1 (No. 2)
P1 (No. 2)
P1 (No. 2)
P1 (No. 2)
˚
a (A)
18.330(2)
21.979(3)
23.603(3)
106.888(2)
112.276(2)
98.504(2)
8054
8.9638(8)
18.468(2)
20.384(2)
72.423(3)
83.966(4)
83.479(4)
3187
12.930(2)
15.620(2)
19.432(3)
82.840(2)
80.687(2)
88.633(2)
3843
9.6316(7)
12.2357(9)
19.032(1)
83.686(3)
78.008(2)
75.498(2)
2120
˚
b (A)
12.6060(9)
20.685(2)
11.431(6)
20.470(6)
˚
c (A)
a (°)
b (°)
c (°)
103.405(2)
91.38(5)
3
˚
V (A )
3952
1.771(4)
1.36
2123
1.874(4)
3.2
Dcalc (g cmꢂ3) (Z)
1.715(4)
1.29
2.127(4)
1.13
1.440(2)
0.90
1.739(2)
1.29
lMo (mmꢂ1
)
Specimen (mm)
‘T’min/max
2hmax (°)
Nt
0.45, 0.35, 0.25
0.84
75
78323
20600 (0.040)
15991
0.041
0.35, 0.21, 0.06
0.87
58
74966
39094 (0.039)
25823
0.06, 0.03, 0.015
(No corrections)
43
15053
13497
11738
0.069
0.17
0.60, 0.45, 0.30
0.79
50
0.32, 0.28, 0.22
0.72
60
37013
13300 (0.051)
9983
0.50, 0.40, 0.33
0.90
75
43474
21692 (0.019)
18368
–
N (Rint
No
R1
)
3738
2353
0.084
0.089
0.050
0.12
0.072
0.22
0.033
0.074
wR2
0.10
phosphine to give complexes such as [Ru3(CO)6(l-H)2(l-
PR2)2(l-dppm)] [35] rather than [Ru3(CO)8(l-H)(l-
PR2)(l-dppm)].
Although, the multiple stereogenic centres present in the
ligands and complexes rendered their spectroscopic charac-
terisation difficult, their influence was clearly observed.
Once again it has been shown that metal–metal bonding
does not impart any higher degree of structural integrity
and that a complex interplay of electronic and steric effects
is evident in these complexes.
The PO distance in [Ru3(CO)9(l-P(OMe)3)] [43]
˚
1.64(1) A (< >, two independent molecules) is only margin-
˚
ally different to that of 7, 1.615(1) A and suggestive of a
single PO bond. Similarly the Ru–P(O) distances are also
directly comparable to those of 7. It is of interest is that
in neither case of complexes 6 or 7, did the benzyl methoxy
substituent become involved in the bonding, presumably a
consequence of steric constraints.
Acknowledgements
We thank the Australian Research Council for funding
part of this work. NSH was the holder of an Australian
Postgraduate Award. Use of the ChemMatCARS Sector
15 at the Advanced Photon Source, was supported by the
Australian Synchrotron Research Program, which is
funded by the Commonwealth of Australia under the Ma-
jor National Research Facilities Program. ChemMatCARS
Sector 15 is also supported by the National Science Foun-
dation/Department of Energy under Grant numbers
CHE9522232 and CHE0087817 and by the Illinois Board
of Higher Education. The Advanced Photon Source is sup-
ported by the U.S. Department of Energy, Basic Energy
Sciences, Office of Science, under Contract No. W-31-
109-Eng-38.
4. Conclusions
We have found that several pnictogen based multifunc-
tional ligands interact with either [Ru3(CO)10(l-dppm)] or
[Ru3(CO)12] to form a number of unusual new complexes,
in which the phenylphosphinoethanethiol ligand LH2 may
upon deprotonation bind intramolecularly or span two
[Ru3(CO)x(l-dppm)] moieties. The retention of the PH
functionality in both 2 and 3 suggests that the thiol unit
is much more reactive in these cases giving both a bridging
hydride and a bridging sulfide. While not strictly compara-
ble, HSCH2CH2AsMe(C6H4CH2OMe), in its reaction with
[RuCo2(CO)11] also produced similar results as well as
cluster breakdown as seen in the structure of 5. However,
more forcing conditions could implicate the PH group in
a reaction with l2-S and l2-P groups found in the structure
of complex 4. The reactivity of a secondary phosphine was
clearly illustrated in the reaction of HPMe(C6H4CH2OMe)
with 1, which in the case of complex 6, gave a product
with an unprecedented structure, and, with 7, showed that
oxidation is possible, although it is not clear at what point
this has occurred.
Appendix A. Supplementary material
CCDC 664866, 664867, 664868, 664869, 664870, 664871
contain the supplementary 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.
Supplementary
data associated with this article can be found, in the online
version, at doi:10.1016/j.jorganchem.2008.01.040.

1750
L.T. Byrne et al. / Journal of Organometallic Chemistry 693 (2008) 1738–1750
[22] G.M. Sheldrick, SHELXL-97: A Program for Crystal Structure Refine-
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