Reactions of diphenylpyridylphosphine with H2Os 3(CO)10 and H4Ru4(CO)12, P-C bond splitting in the coordinated ligand and isolation of the oxidative addition products

Article abstract of DOI:10.1016/j.jorganchem.2005.08.007

The reactions of diphenylpyridylphosphine ligand with H₂Os ₃(CO)₁₀ and H₄Ru₄(CO)₁₂ were studied. It was found that the thermodynamic products of these reactions, (μ-H)Os₃(CO)₉(μ₃,κ²- PhP(2-C₅H₄N)) (2) and H₃Ru₄(CO) ₁₀(μ₃,κ²-PhP(2-C₅H ₄N)) (4), are formed through the oxidative addition of a P-Ph bond in the coordinated ligand and subsequent reductive elimination of benzene. In the case of triosmium cluster an unusually stable intermediate compound, (μ-H)₂Os₃(CO)₈(μ₃, κ²-PhP(2-C₅H₄N))(Ph) (1), containing cis hydride and σ-bonded phenyl was isolated and fully characterized. This cluster eliminates benzene to give (2) only under heating above 50 °C. Reaction of H₄Ru₄(CO)₁₂ with diphenylpyridylphosphine gives first the H₄Ru₄(CO) ₁₀(μ,κ²-Ph₂P(2-C₅H ₄N)) cluster (3) with a bridging (P,N) coordination of the starting ligand, which easily converts into the phosphide cluster (4) at room temperature. The structures of the clusters (1)-(4) were established using ¹H and ³¹P NMR spectroscopy and X-ray crystallography. Variable temperature ¹H NMR study of (3) and (4) showed that the hydride environment in (3) is stereochemically nonrigid and complete exchange of all hydrides was observed at room temperature. The cluster (4) exists in solution as an equilibrium mixture of two isomers with different disposition of hydrides relative to the bridging pyridylphosphide moiety.

Full text of DOI:10.1016/j.jorganchem.2005.08.007

Journal of Organometallic Chemistry 691 (2006) 111–121
www.elsevier.com/locate/jorganchem
Reactions of diphenylpyridylphosphine with H2Os3(CO)10
and H4Ru4(CO)12, P–C bond splitting in the coordinated ligand
and isolation of the oxidative addition products
a
a
Vadim I. Ponomarenko , Tatiana S. Pilyugina a,1, Vassily D. Khripun ,
a
a,
b
b
Elena V. Grachova , Sergey P. Tunik *, Matti Haukka , Tapani A. Pakkanen
a
Department of Chemistry, St. Petersburg University, Universitetskii pr., 26, St. Petersburg, 198504, Russian Federation
b
Department of Chemistry, University of Joensuu, P.O. Box 111, FIN-80101 Joensuu, Finland
Received 24 June 2005; received in revised form 2 August 2005; accepted 3 August 2005
Available online 28 September 2005
Abstract
The reactions of diphenylpyridylphosphine ligand with H2Os3(CO)10 and H4Ru4(CO)12 were studied. It was found that the thermo-
dynamic products of these reactions, (l-H)Os3(CO)9(l3,j2-PhP(2-C5H4N)) (2) and H3Ru4(CO)10(l3,j2-PhP(2-C5H4N)) (4), are formed
through the oxidative addition of a P–Ph bond in the coordinated ligand and subsequent reductive elimination of benzene. In the case of
triosmium cluster an unusually stable intermediate compound, (l-H)2Os3(CO)8(l3,j2-PhP(2-C5H4N))(Ph) (1), containing cis hydride and
r-bonded phenyl was isolated and fully characterized. This cluster eliminates benzene to give (2) only under heating above 50 ꢀC. Reac-
tion of H4Ru4(CO)12 with diphenylpyridylphosphine gives first the H4Ru4(CO)10(l,j2-Ph2P(2-C5H4N)) cluster (3) with a bridging (P,N)
coordination of the starting ligand, which easily converts into the phosphide cluster (4) at room temperature. The structures of the clus-
ters (1)–(4) were established using 1H and 31P NMR spectroscopy and X-ray crystallography. Variable temperature 1H NMR study of (3)
and (4) showed that the hydride environment in (3) is stereochemically nonrigid and complete exchange of all hydrides was observed at
room temperature. The cluster (4) exists in solution as an equilibrium mixture of two isomers with different disposition of hydrides rel-
ative to the bridging pyridylphosphide moiety.
ꢁ 2005 Elsevier B.V. All rights reserved.
Keywords: Cluster compounds; P Ligands; Ruthenium; Osmium; X-ray diffraction
1. Introduction
[10,12–14]. It is well known that r-bonded (M–C) organic
ligands can be easily removed from coordination sphere of
transition metal complexes by reductive coupling with
adjacent cis-hydride. This classic type of reactions evidently
occurs on the treatment of the nonhydride Ru3 benzoyl
containing clusters with dihydrogen [15], [BH4]ꢀ [15] or
PPh2H [16]. Similar reactivity patterns were also observed
for the clusters containing g1-phenyl provided that a
source of hydride was introduced in the reaction mixture
[17–20]. In all these cases the reductive elimination is so
kinetically and thermodynamically favorable that it was
impossible to observe the intermediate hydride cluster.
On the contrary, a series of mono- and binuclear transition
metal complexes containing hydride and alkyl (aryl)
Reactions of pyridylphosphines with ruthenium, rho-
dium and osmium clusters were studied in detail because
of the versatile coordination chemistry of these ligands
on the polymetal centers [1–11], which includes oxidative
P–C bond cleavage to give the face-bridging pyridylphos-
phide and formation of either r-phenyl or bridging pyridyl
or benzoyl moieties derived from the starting phosphine
*
Corresponding author. Tel.: +7 812 4284028; fax: +7 812 4286939.
E-mail address: stunik@chem.spbu.ru (S.P. Tunik).
Departmentof Chemistry, 6-331Massachusetts Instituteof Technology,
1
77 Massachusetts Ave. Cambridge, MA 02139, USA.
0022-328X/$ - see front matter ꢁ 2005 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2005.08.007

112
V.I. Ponomarenko et al. / Journal of Organometallic Chemistry 691 (2006) 111–121
ligands were isolated and studied in detail because of their
importance for understanding the mechanisms of catalytic
activation of the hydrocarbon C–H bond, see for example
[21–32]. Some particularly stable cis ‘‘hydride-aryl’’
complexes of ruthenium [33], iridium [34–36], platinum–
tungsten [37] dimers, [Me2Si]-ansa-bridged permethylme-
tallocene systems [22,24,38] allowed X-ray crystallographic
study. In the present paper we report the H2Os3(CO)10 and
H4Ru4(CO)12 reactions with diphenylpyridylphosphine
under various conditions and structural characterization
of four novel products formed in these reactions. The
(l-H)2Os3(CO)8(l3,j2-PhPPy)(Ph) (1) cluster is the first
fully characterized hydride cluster containing cis hydride
and phenyl ligands, which reductively eliminate benzene
only under rather harsh conditions.
gressively increased temperature are shown in Scheme 1,
which summarizes the chemistry studied in the present pa-
per and the data obtained earlier [10].
The room temperature reaction of coordinatively unsat-
urated H2Os3(CO)10 cluster with the pyridyl-phosphine
ligand immediately gives the addition products H2Os3
(CO)10(j1-Ph2P(2-C5H4N)), which has been characterised
by IR and NMR spectroscopy. Its 31P chemical shift fits
well to that found earlier for the adduct (2.81 ppm [7])
and the IR characteristics are very close to those revealed
for analogous H2Os3(CO)10(j1-PR3) clusters [39,40]
that testifies in favour of terminal coordination of
diphenylpyridylphosphine to one of the osmium atoms
bridged by the hydride ligands. Heating of the adduct in
boiling hexane for 1.5 h gives (l-H)2Os3(CO)8(l3,j2-PhP-
(2-C5H4N))(Ph) (1) together with substantially smaller
amount of (l-H)Os3(CO)9(l3,j2-PhP(2-C5H4N)) (2). The
formation of 1 from the above j1-adduct occurs through
coordination of the pyridyl nitrogen and intramolecular
2. Results and discussion
The reactions of diphenylpyridylphosphine with
H2Os3(CO)10 and Os3(CO)10(NCMe)2 occurring at pro-
oxidative cleavage/addition of
a P–C bond in the
Os3(CO)10(NCMe)2
H2Os3(CO)10
25o C
+Ph2PPy
+Ph2PPy
25o C
{H2Os3(CO)10(κ1-Ph2PPy)}
680C
Ph
P
N
Os(CO)3
Ph
Ph
(O
C) O
s
3
N
P
O
s(CO)4
H
(1)
(
OC) O
s
Os(CO)3
3
100o C
Os(C
O)2
H
+H2
+CO
100o C
120o C
Ph
N
P
(OC
)3Os
Os(CO)3
Os(CO)3
Ph
N
P
(OC)
3Os
(2)
Os(CO)3
CO)3
H
Os(
+
Scheme 1. The reactions of diphenylpyridylphosphine with H2Os3(CO)10 and Os3(CO)10(NCMe)2.

V.I. Ponomarenko et al. / Journal of Organometallic Chemistry 691 (2006) 111–121
113
coordinated phosphine. These transformations are also
accompanied by dissociation of two CO ligands to keep
the closed triangular Os3 framework. The cluster 2 is evi-
dently a result of the further transformation of 1, which
consists of reductive elimination of benzene and reverse
addition of a CO ligand to keep 48-electron count of the
triangular cluster. Accumulation of benzene in the course
of this reaction was detected by proton NMR. It has been
also shown independently that gentle heating of 1 in n-hep-
tane under CO atmosphere gives 2 in nearly quantitative
yield that clearly evidences the left branch of Scheme 1.
The same reaction in the absence of CO also gives 2 in
slightly lower yield along with accumulation of decomposi-
tion products. The observed decomposition is an expect-
able result under these conditions because some of the
starting cluster molecules serve as a source of CO to pro-
duce 2. Molecular structures of 1 and 2 in solid state have
been established by X-ray crystallography. ORTEP views
of these molecules are shown in Figs. 1 and 2, selected bond
lengths and angles are given in Table 2.
Fig. 2. ORTEP views of the 2 molecule. Thermal ellipsoids are drawn at
Three osmium atoms in 1 form a closed triangle in
agreement with 48 electron count for this cluster. The clus-
ter framework is surrounded by eight terminal CO ligands,
two bridging hydrides, g1-coordinated phenyl radical and
phenylphosphidopyridyl moiety, which bridges the osmium
triangle in nearly symmetric manner. The phenyl ligand
occupies a terminal position at the Os(2) atom cis to the
bridging phosphorus as it should be expected for the coor-
dinated fragments formed through the oxidative addition
of the ‘‘P–Ph’’ moiety. This stereochemistry is very much
different of that observed in the main product, Os3-
(CO)9(l3,j2-PhP(2-C5H4N))(Ph), obtained upon heating
of the nonhydride Os3(CO)10(l,j2-Ph2P(2-C5H4N)) cluster
in heptane solution (98 ꢀC) for 4 h [10]. The metallated
phenyl radical in Os3(CO)9(l3,j2-PhP(2-C5H4N))(Ph) is
50% probability level.
coordinated to the nitrogen bound osmium atom that is
a result of the oxidative addition followed by the phenyl
group migration across the Os(P-bound)–Os(N-bound)
bond. It is worth mentioning that among the products sep-
arated from this reaction mixture the authors [10] revealed
the Os3(CO)9(l3,j2-PhP(2-C5H4N))(l-C(O)Ph) cluster con-
taining bridging benzoyl ligand, which spans the Os–Os
edge bridged by the phosphide group. This means that in
the transformation of the unobservable cis-(phenyl-phos-
phide) intermediate the CO migratory insertion into the
Os–Ph bond competes with the intermetallic phenyl ligand
shift, the latter being either kinetically and/or thermody-
namically favourable.
The Os–Os bond lengths in 1 fall in the interval typical
for the closed triosmium cluster frameworks. Two of these
bonds spanned by the hydride ligands are substantially
˚
longer (2.9992(5) and 2.9539(4) A) compared to the third
˚
one (2.8354(4) A). It has to be noted that in the nonhydride
congener of 1, Os3(CO)9(Ph)(l3,j2-PhP(2-C5H4N)) [10],
the Os–Os bond bridged by the phosphido group is the
˚
shortest one (2.791 A) in the molecule due to the effect of
bridging phosphorus atom. The presence of a hydride on
the same edge of 1 results in a dramatic elongation of this
˚
bond up to 2.9539(4) A. This trend is typical for the
phosphido triosmium clusters containing bridging hydrides
[41–48] and can be used to reliably locate the hydride posi-
tion on the clusters framework. The osmium–phosphorus
bond lengths in 1 are very close to each other, see Table 2,
˚
and very similar to the values (2.344 and 2.338 A) found
in the analogous nonhydride Os3(CO)9(l3,j2-PhP-
(2-C5H4N))(Ph) cluster [10]. The Os(1)–N(1) bond is
˚
slightly shorter (ca. 0.06 A) compared to the corresponding
distance in the pyridylphosphide triosmium clusters
mentioned above [10]. The Os–C distances for the carbonyl
Fig. 1. ORTEP views of the 1 molecule. Thermal ellipsoids are drawn at
50% probability level.

114
V.I. Ponomarenko et al. / Journal of Organometallic Chemistry 691 (2006) 111–121
ligands in 1 are very close to each other, except Os(1)–C(2)
and Os(2)–C(5), see Table 2. The latter bonds are substan-
tially longer due to pronounced trans influence of the
phosphide ligand. Two bridging hydrides were located
from the difference Fourier map. They occupy the bridging
positions over the Os(2)–Os(3) and Os(1)–Os(3) edges that
hydrides in triosmium clusters. The signal is splitted into
a doublet (2JP–H = 14.3 Hz) due to the interaction with
the bridging phosphorus. The phenyl multiplet around
7.5 ppm and four typical signals of coordinated pyridyl
protons (9.04, 7.73, 7.07 and 6.34 ppm) are observed in
the lowfield area of the proton spectrum.
It was revealed earlier [10] (see Scheme 1) that Os3-
(CO)10(NCMe)2 reacts with Ph2P(2-C5H4N) to give first
Os3(CO)10(l2,j2-Ph2P(2-C5H4N)). Thermal treatment of
this cluster in boiling heptane results in oxidative addition
of a P–Ph moiety to afford the phosphido Os3(CO)9(l3,j2-
PhP(2-C5H4N))(Ph) cluster. We found that under an atmo-
sphere of H2 the Os3(CO)10(l2,j2-Ph2P(2-C5H4N)) cluster
smoothly give 2 in 64% yield. This reaction proceeds
through oxidative addition of dihydrogen but the interme-
diate phenyl-hydride species 1 was not observed due to fast
reductive elimination under these conditions.
Scheme 1 comprises essential features of coordination
chemistry of diphenylpyridylphosphine in two labile trios-
mium clusters – H2Os3(CO)10 and Os3(CO)10(NCMe)2.
Fast coordination of the ligand to the both labile species
and further oxidative cleavage of a P–C bond afford trinu-
clear clusters containing l3,j2-phosphido and g1-phenyl
ligands. The most interesting finding of the present study
is unusual stability of the phenyl-hydrido cluster 1, which
allowed its isolation and full characterization in the solid
state and in solution. Intermediacy of the species of this
sort is a common point of the mechanistic schemes describ-
ing stoichiometric reductive elimination and related cata-
lytic processes. Thatꢀs why considerable attention has
been already paid to investigation of this chemistry and
structural characterization of the isolable species, which
belong to the family of mono- and binuclear transition
metal complexes [22,24,33–38]. However, 1 is the first
example of cluster molecule containing cis-(R–M–H) frag-
ment, which is stable in the solid state and solution under
ambient conditions. Unexpectedly low reactivity of 1 can
be partly explained by stereochemical rigidity of the
hydrides, which do not display any dynamics at room tem-
perature. Relatively high activation barrier for the hydrides
intermetallic scrambling is very likely related to the lack of
their reactivity. Necessity to compensate elctronic and
coordinative unsaturation arising from reductive elimina-
tion of the R–H moiety calls for the presence of a substitut-
ing ligand to right-shift the reaction equilibrium. The
absence of a two-electron donor in the reaction mixture
also retards the reductive elimination and stabilizes 1.
For the sake of comparison we also studied reactions of
another hydride cluster, H4Ru4(CO)12 with diphenylpyr-
idylphosphine. Direct thermal reaction of these reagents
proved to be ineffective to give only minor conversion of
the starting cluster. However, a low temperature reaction
in the presence of trimethylamine N-oxide followed by
gentle heating of the dichloromethane solution gave
H4Ru4(CO)10(l,j2-Ph2P(2-C5H4N)) (3) (39%) and H3-
Ru4(CO)10(l3,j2-PhP(2-C5H4N)) (4) (7%). The reaction
products have been chromatographically separated and
1
has been also confirmed by the H NMR measurements.
The hydrides appear in the proton NMR spectrum at
ꢀ12.30 ppm (d, JP–H = 5.8 Hz) and ꢀ17.03 ppm (d, JP–H
= 8.0 Hz) that is typical of bridging coordination mode
of these ligands. It is evidently sensible to assign the low
field signal in the spectrum of 1 to H(02) and the high field
resonance to H(01) taking into account the chemical shift
of the hydride ligand in 2 (ꢀ18.10 ppm, d, JP–H
=
14.3 Hz). The values of spin–spin coupling constants for
these signals are similar to those found for cis stereochem-
istry of the phosphide phosphorus and proton nuclei
[41,42,45,47]. No hydride dynamics was observed in 1 at
ambient temperature. The low field part of the spectrum
consists of four multiplets (8.86 ppm, d, J = 5.5 Hz, H6;
7.64 ppm, dd, J = 5.7, 3.6 Hz, H4; 7.03 ppm, ddd J = 5.7,
5.5, 1.2 Hz, H5; 6.47 ppm, dd, J = 3.6, 7.5 Hz, H3) corre-
sponding to the pyridyl protons and of the complex phenyl
multiplet (10 H) centred at 7.4 ppm. The position and mul-
tiplicity of the pyridyl proton signals are in excellent agree-
ment with the data obtained earlier for Ru3 and Os3
pyridyl-phosphide clusters [10,14]. The proton and phos-
phorus NMR data obtained for 1 indicate that the struc-
ture found in the solid state remains unchanged in solution.
Reductive elimination of benzene from 1 occurs sponta-
neously at the temperature above +50 ꢀC, but smooth and
nearly quantitative conversion of 1 into 2 was observed at
100 ꢀC in the heptane solution under CO atmosphere. The
presence of CO in the reaction mixture substantially facil-
itate reductive elimination because carbonyl ligand is a
stoichiometric reagent in this process and it is also well
known that reductive elimination equilibrium is right
shifted by the presence of a substituting ligand, which fills
the coordination vacancy formed upon elimination. The
metal framework in 2 adopts closed triangular configura-
tion in accord with the 48-electron count for this cluster.
Nine terminal COs (three at each osmium atom), one
bridging hydride and l3,j2-phenylpyridylphosphide sur-
round the osmium triangle. The molecule adopts Cs sym-
metry with the mirror plane through Os(1), N(1) and
P(1) atoms. Main structural parameters of the metal frame-
work and ligand environment in 2 are essentially similar to
those found in 1, see Table 2. The Os(2)–Os(3) bond
bridged by the hydride and phosphido group is the longest
˚
one (2.9289(5) A), the other metal–metal distances are sub-
˚
stantially shorter, 2.8528(5) and 2.8384(5) A. As mentioned
above this structural feature can be effectively used to
locate the hydride position in the molecules of this sort in
addition to the calculations made with the use of XHYDEX
program [49]. The NMR measurements confirmed the
structure found in the solid state. The hydride signal
(ꢀ18.1 ppm) appeared in the area typical for the bridging

V.I. Ponomarenko et al. / Journal of Organometallic Chemistry 691 (2006) 111–121
115
characterized spectroscopically. Solid state structures of
both clusters were determined crystallographically, OR-
TEP views of these molecules are shown in Figs. 3 and 4,
selected bond lengths and angles are given in Table 3.
The cluster 3 is a typical example of the bridging (P,N)
coordination of pyridylphosphine. As in the other polynu-
clear compounds of this sort [2–11] the pyridylphosphine
bridge spans an edge of the metal polyhedron to form
the five membered (Ru–P–C–N–Ru) dimetallacycle. Four
ruthenium atoms in 3 form a closed tetrahedral framework
in accord with the PSEPT rules, which gives 60 electrons
count for this cluster. Ten CO ligands together with the
phosphorus and nitrogen functionalities of the pyridyl-
phosphine ligand occupy twelve terminal sites, three at
each ruthenium atom, in a manner similar to that found
in the osmium analogue H4Os4(CO)10(l,j2-Ph2P(C5H4N))
[4]. The pyridylphosphine moiety bridges one of two Ru–
Ru bond, which are not spanned by the hydrides, to form
the dimetallacycle perpendicular to the Ru(1)–Ru(2)–Ru(3)
triangle. The ‘‘Ru3(P,N)’’ structural fragment is a planar
chiral [11] unit, the both S and R configurations of which
being presented in the crystal cell. Metal–metal distances
in 3 can be divided into two groups, one of which contains
four long Ru–Ru bonds spanned by bridging hydrides.
Two other Ru–Ru distances are substantially shorter (ca
H(03)
H(01)
H(02)
Fig. 4. ORTEP views of the 4 molecule. Thermal ellipsoids are drawn at
50% probability level.
˚
pal geometric parameters (bond length and angles) of the
‘‘Ru3(l-P,N)’’ fragment are very similar to those found
for the analogous clusters containing the second and third
row transition metals [2–4,6,9–11] in this structural unit. In
these clusters, as well as in 3, disparity of the rather long
metal–metal bonds and short bite angle of the (P,N) ligand
results a strained coordination mode of the bridging moi-
ety. In particular, the Ru(1)–Ru(2)–P(1) angles is quite
small (82.4ꢀ) compared to the corresponding cis angles
for the nonstrained CO ligands (90–96ꢀ) and the Ru–N–
C–P–Ru dimetallacycle in 3 is nonplanar with the Ru(1)–
N(1)–C(32)–P(1) and Ru(2)–P(1)–C(32)–N(1) angles equal
to 17.1ꢀ and 37.5ꢀ, respectively. On the contrary, the
‘‘Co2(diphenylpyridylphosphine)’’ bridge in the cobalt con-
taining polynuclear complexes [5,7,8] is substantially lesser
strained due to better match between the ligand bite angle
and shorter Co–Co bond that is indicated by nearly planar
conformations of the dimetallacycles.
0.15 A, see Table 3), the trend being absolutely general
for the parent H4Ru4(CO)12 cluster [50] and its substituted
derivatives [51–53] containing bridging ligands. The Ru(1)–
Ru(2) bond bridged by the pyridylphosphine moiety is the
shortest one in 3 that is evidently a result of the short bite
angle of the PN bridging ligand. Configuration and princi-
Four hydride ligands in 3 have been located from a dif-
ference Fourier map. The arrangement of the hydrides
around the Ru4 framework is exactly the same as that
found in the osmium analogue [4] of 3 and was not dis-
torted (compared to H4Ru4(CO)12) by the substitution of
two COs for pyridylphosphine. Two of the hydrides bridge
the Ru–Ru bonds trans to the phosphorus and nitrogen
atoms of the pyridylphosphine moiety. Two others occupy
bridging positions on the triruthenium face perpendicular
to the dimetallacycle. It is interesting to note that the dispo-
sition of the hydrides in 3 differs substantially of that ob-
served in the bridging diphosphine substituted derivatives
of H4Ru4(CO)12 [51–54]. In the diphosphine substituted
clusters three of the four hydrides symmetrically bridge
H(03)
H(01)
H(02)
H(04)
Fig. 3. ORTEP views of the 3 molecule Thermal ellipsoids are drawn at
50% probability level.

116
V.I. Ponomarenko et al. / Journal of Organometallic Chemistry 691 (2006) 111–121
the tetrahedron face perpendicular to the ‘‘Ru3(P,P)’’ frag-
ment, whereas the fourth occupies a trans position relative
to one of the phosphorus atoms. The difference in the de-
sign of the hydrides environment for the P,P and P,N
substituted H4Ru4(CO)12 derivatives is an evident conse-
quence of the pyridyl functionality ‘‘ligand effect’’, which
ought to be mentioned but can be hardly rationalized on
the basis of the present knowledge in this field of cluster
chemistry.
3. Solution structure and dynamics of the hydride ligands in 3
and 4
The VT proton NMR spectrum of 3 demonstrates the
hydride ligands dynamics above ꢀ40 ꢀC, Fig. 5. At the
low temperature limit (ꢀ50 ꢀC) the spectrum in the hydride
area displays four signals that is in agreement with the
asymmetric structure of the hydride environment. Two of
the signals (ꢀ14.47 and ꢀ23.15 ppm) are not splitted
by magnetic interaction with the phosphorus nucleus
In line with the chemistry described above and other
examples of pyridylphosphines reactions with the nonhy-
dride Ru3 [12–14] and Os3 [10] clusters we found that coor-
dinated Ph2P(2-C5H4N) easily breaks a P–C bond to afford
the phosphide H3Ru4(CO)10(l3,j2-PhP(2-C5H4N)) cluster
(4). The stoichiometry of 4 clearly indicates that this is a
product of reductive elimination of benzene from 3, which
occurs under very mild conditions compared to the 1 ! 2
transformation. This prevented observation of a phenyl-
hydride intermediate because of a very low barrier to the
H–Ph reductive elimination. This situation looks very
similar to immediate elimination of benzene or benzalde-
hyde from the nonhydride Ru3(l-C(O)Ph)(l3,j2-PhP-
(2-C5H4N))(CO)9 [15] upon their treatment with H2,
[BH4]ꢀ or HPPh2. Formation of this intermediate contain-
ing oxidatively added phenyl moiety is well supported by
the results obtained for analogous reactions of the nonhy-
dride Ru3 clusters [12–15]. It is worth noting that the reac-
tion with [BH4]ꢀ occurs at room temperature with
immediate release of benzaldehyde. These observations
indicate that the coordination of the hydride to the ruthe-
nium cluster core (in one or another way) is the limiting
stage of the process followed by fast CO insertion and
reductive elimination of benzaldehyde.
2
whereas two others (ꢀ16.17 ppm, JP–H = 21.7 Hz) and
2
(ꢀ16.31 ppm, JP–H = 17.2 Hz) appear as clearly resolved
doublets. These NMR data are consistent with the struc-
ture of the ‘‘H4Ru4PN’’ fragment found in the solid state.
Assignment of the hydride signals compatible with this
structure is also shown in Fig. 5. The difference between
2JP–H coupling constants for H(03) and H(04) hydrides is
completely consistent with their cis and trans disposition
with respect to the phosphorus atom of the ligand, P(1)–
Ru(2)–H angles equal 80.6ꢀ and 177.9ꢀ, respectively. Two
other (H(01) and H(02)) hydrides are three bonds sepa-
rated from the phosphorus nucleus and their signals do
not display P–H couplings. The signals of the hydrides
ligands simultaneously start to broaden above ꢀ40 ꢀC that
points to the exchange process(es) involving all hydrides.
The molecule of 4, Fig. 4, consists of a closed (60 elec-
trons) ruthenium tetrahedron surrounded by eight terminal
CO, two bridging carbonyls, three hydrides and l3,j2 coor-
dinated {PhP(C5H4N)} phosphide ligand. This structural
pattern possesses a symmetry plane through the Ru(1),
N(1) and P(1) atoms that makes the molecule achiral.
The metal–metal bond length in the ruthenium tetrahedron
display regular trends typical for the other substituted
H4Ru4(CO)12 substituted clusters. The Ru–Ru bonds
bridged by the hydrides are the longest ones (2.9358(3),
˚
2.9385(3), 2.9772(3) A), the Ru–Ru bond spanned by the
˚
˚
phosphide is slightly shorter (2.8712(3) A), whereas the car-
bonyl bridged Ru(2)–Ru(4) (2.7398(3) A) and Ru(3)–Ru(4)
˚
(2.7512(3) A) bonds are the shortest in the molecule. Coor-
dination of the phosphide phosphorus to Ru(2) and Ru(3)
atoms in 4 is nearly symmetric and the corresponding
˚
bonds length (2.2872(8) and 2.3070(8) A, respectively) are
very close to the Ru–P distance found in 3. The Ru(1) to
N(1) bond length also remains nearly unchanged. Two of
the carbonyl ligands in 4 occupy bridging positions on
the Ru(2)Ru(4) and Ru(3)Ru(4) edges. The bridging COs
are coordinated in a strongly asymmetric manner (Table
3), that does not match CS symmetry group of the molecule
and is most probably dictated by the crystal packing effects.
1
Fig. 5. The VT H NMR spectrum of 3, signals of impurities are marked
with asterisks.

V.I. Ponomarenko et al. / Journal of Organometallic Chemistry 691 (2006) 111–121
117
The EXSY spectrum run at ꢀ30 ꢀC (Fig. S1, Supporting
Information) indicates that all hydrides exchange with each
other at nearly equal rate.
N
N
P
1
P
The limiting low temperature H NMR spectrum of 4,
H'03
H03
Fig. 6, indicates that this cluster exists in solution as a mix-
ture of two isomers. The signals of the isomers in the hy-
dride area are well resolved and can be interpreted on the
basis of spin–spin coupling constants observed in each of
the spectroscopic patterns. The major isomer displays
two signals in 2/1 ratio. The low field resonance of double
H01
H02
H'02
H'01
2
4, major isomer
Scheme 2. Exchange of hydrides in 4.
4, minor isomer
intensity is splitted into a doublet with a typical cis JP–H
equal to 8.8 Hz, whereas the high field signal appears as
a singlet. These observations are in agreement with the
structure of the ‘‘Ru4H3P’’ fragment revealed in the solid
state and plausible spin–spin couplings in this system.
The spectrum of the minor isomer consists of three signals
of single intensity, two of which appear in the close vicinity
to the low field signal of the major isomer and the chemical
shift of the third one is very close to that of the high field
resonance of the major species. This is indicative of com-
pletely asymmetric structure of the ‘‘Ru4H3P’’ fragment
in the minor isomer. Two low field signals display spin–
spin coupling constants equal to 17.7 and 10.3 Hz that
points to two bond coupling of the corresponding hydrides
to the phosphorus nucleus. The most probable structure
compatible with the position of these signals and their cou-
plings to phosphorus is shown in Scheme 2. In this struc-
ture the hydride, which occupy the Ru(1)–Ru(4) edge
appears in the spectrum as a singlet at ꢀ22.74 ppm. This
is the only bridging position on the ruthenium tetrahedron,
which prevents coupling with the phosphide phosphorus
that makes this assignment unambiguous. Two low field
pling (17.7 Hz) that very probably correspond to nearly
trans disposition of the intervening nuclei as shown in
Scheme 2. Heating of the solution of 4 up to +23 ꢀC results
in averaging of the low field and high field resonances of
the isomers to give two broad signals at ꢀ17.40 and
ꢀ23.10 ppm, respectively (Fig. 6). This observation indi-
cates that in the temperature range studied there is an ex-
change between major and minor isomers, which may be
also accompanied by intramolecular hydrides scrambling.
4. Experimental
The following reagents were purchased commercially
and purified prior to use: diphenyl-2-pyridylphosphine (Al-
drich) was recrystallized from hot methanol; Ru3(CO)12
(Aldrich) was recrystallized from hot benzene; trimethyl-
amine N-oxide (Aldrich) was sublimed in vacuo. The trios-
mium H2Os3(CO)10 [55], Os3(CO)10Ph2P(2-C5H4N) [10]
and tetraruthenium H4Ru4(CO)12 [56] clusters were synthe-
sized according to published procedures. Reagent grade
solvents: petroleum ether (40–70 ꢀC), methanol, dichloro-
methane and hexane were distilled over appropriate drying
agents prior to use. Analytical TLC, used for monitoring of
the reaction course, was carried out on Merck aluminum
sheets coated with 0.5 mm silica gel 60. The products were
purified by column chromatography on Silica (5–40 mesh).
The IR spectra were recorded on a Specord M80 spectrom-
eter. Mass spectra were measured on an MX-1321 instru-
2
doublets of the minor isomer display different JP–H cou-
plings, one of which (ꢀ18.10 ppm) is very close (10.3 Hz)
to the value observed in the doublet signal of the major
species (8.8 Hz). It is therefore sensible to assign this signal
to the hydride occupying the Ru–Ru edge spanned by the
P–C–N bridge that puts the phosphorus and the hydride
into cis position. The other doublet signal (ꢀ17.68 ppm)
displays substantially higher phosphorus to hydride cou-
1
ment (electron impact, ionizing potential 70 eV). The H
and 31P NMR spectra were recorded on a Bruker DX
300 spectrometer. The chemical shifts were referenced to
residual solvent resonances and external 85% H3PO4 in
+23oC
1
the H and 31P spectra, respectively. Microanalyses were
H(01),
H(03)
H(02)
carried out in the Analytical Laboratories of the University
of Joensuu, Osaka-City University and St. Petersburg State
University.
H(02)’
-50oC
H(01)’
H(03)’
4.1. Reaction of H2Os3(CO)10 and Ph2P(2-C5H4N)
-16.0 -17.0 -18.0 -19.0 -20.0 -21.0 -22.0 -23.0 -24.0
(ppm)
Ph2P(2-C5H4N) (46.4 mg, 0.176 mmol) was dissolved in
20 ml of hexane and H2Os3(CO)10 (150.8 mg, 0.176 mmol)
was added to this solution under vigorous stirring. Forma-
tion of the H2Os3(CO)10(j1-PPh2(2-C5H4N)) adduct was
Fig. 6. The limiting low temperature and room temperature 1H NMR
spectra of 4. Signals of minor isomer are marked with apostrophe.

118
V.I. Ponomarenko et al. / Journal of Organometallic Chemistry 691 (2006) 111–121
evidenced by precipitation of yellow solid and decoloration
of the starting dark violet solution. The adduct was
decanted and washed with hexane (177 mg, 0.159 mmol,
89.9%). IR (CH2Cl2, cmꢀ1): m(CO) 2105w, 2065m,
2048m, 2022vs, 1976sh. 31P {1H} NMR (121 MHz, CDCl3,
25 ꢀC) d = 3.7 (1JOs–P = 203 Hz, 1P).
solvent was then removed in vacuo to give yellow solid
material which was dissolved in 0.5 cm3 of CH2Cl2,
diluted wit 1 cm3 hexane and separated by column
(2.5 · 4 cm) chromatography with petroleum ether/CH2Cl2
(1/1, v/v). (l-H)Os3(CO)9 (l3,j2-PhP(2-C5H4N)) (2) (18 mg,
0.018 mmol, 63.7%) was obtained as the main product of
this reaction.
4.2. Synthesis of (l-H)2Os3(CO)8(l3,j2-PhP(2-C5H4N))
(Ph)
4.4. Thermal conversion of (l-H)2Os3(CO)8(l3,j2-PhP-
(2-C5H4N))(Ph) (1) into (l-H)Os3(CO)9(l3,j2-PhP-
(2-C5H4N)) (2)
85 mg (0.0761 mmol) H2Os3(CO)10(j1-PPh2(2-C5H4N)
was dissolved in 30 cm3 of hot hexane and refluxed for
1.5 h. The color of solution turned from yellow to dark-
brown. Evaporation of the solvent in vacuo gave brown solid
material. It was dissolved in CH2Cl2 (0.7 cm3), diluted with
hexane (1.5 cm3) and transferred onto a chromatographic
column (2.5 · 6 cm). Elution with CH2Cl2/petroleum ether
(1/1, v/v) gave trace amounts of Os3(CO)12, yellow band of
(l-H)Os3(CO)9(l3,j2-PhP(2-C5H4N)) (2) (12.3 mg, 0.012
mmol, 16%) and yellow-brown band of (l-H)2Os3(CO)8-
(l3,j2-PhPPy)(Ph) (1) (36 mg, 0.034 mmol, 44%).
10.3 mg (l-H)2Os3(CO)8(l3,j2-PhP(2-C5H4N))(Ph) (1)
was dissolved in 20 cm3 of heptane and the solution was
purged with CO. The reaction mixture was then refluxed
for 15 min under constant flow of gaseous CO. TLS spot
test showed complete conversion of 1 into 2. The solvent
than was removed in vacuo to give yellow solid material.
1
The H NMR spectrum of the material obtained showed
nearly quantitative (ca 90%) conversion of 1 into 2. A sim-
ilar experiment carried out in CDCl3 solution unambigu-
ously showed reductive elimination of benzene by
emerging of a sharp resonance at 7.37 ppm in the proton
NMR spectrum.
(1) IR (CH2Cl2, cmꢀ1): m(CO) 2085s, 2049vs, 2022vs,
2004m, 1996m, 1960m. 1H NMR (300 MHz, CDCl3,
25 ꢀC) d = 8.86 (d, J = 5.5 Hz, 1H, H6 Py), 7.64 (dd,
J = 5.7, 3.6 Hz, 1H, H4 Py), 7.03 (ddd, J = 5.7, 5.5,
1.2 Hz, 1H, H5 Py), 6.47 (dd, J = 3.6, 7.5 Hz, 1H, H3
Py), 7.60–7.30, (m, 10H, Ph–P and Ph–Os), ꢀ12.2 (d,
JP–H = 6.57 Hz, 1H, OsH), ꢀ16.63 (d, JP–H = 7.28 Hz, 1H,
OsH), 31P {1H} NMR (121 MHz, CDCl3, 25 ꢀC) d = 20.0
(s, 1P). Due to thermal instability of 1 its mass spectrum
displays the highest m/z signal corresponding to elimina-
tion of C6H6 – (M+ ꢀ C6H6) 1013 (Os3 = 570) followed
by fragmentation of a few COs: (M+ ꢀ C6H6 ꢀ nCO),
n = 1–4. Anal. calc. for C25H16N1O8Os3P1 (1060.06): C,
28.33; H, 1.52; N, 1.32. Found: C, 28.41; H, 1.48; N,
1.16%. Single crystals of 1 suitable for an X-ray analysis
were grown from CH2Cl2/hexane mixture at 2 ꢀC.
4.5. Reaction of H4Ru4(CO)12 with Ph2P(2-C5H4N)
H4Ru4(CO)12 (75 mg, 0.101 mmol) and Ph2P(2-C5H4N)
(26.5 mg, 0.101 mmol) were dissolved in 20 ml of CH2Cl2.
The solution was placed in a Schlenk tube and degassed
by three freeze–pump–thaw cycles. Degassed solution of
Me3NO Æ 2H2O (24.6 mg, 0.222 mmol) in a CH3OH/
CH2Cl2 mixture (0.5/5 ml) was transferred via cannula to
the frozen mixture of H4Ru4(CO)12 and Ph2P(2-C5H4N).
The reaction mixture was allowed to warm up to room
temperature under vigorous shaking to give an orange
solution. Heating of this mixture to the boiling point for
6–7 times gave the final vinous-red solution. The solution
was concentrated under vacuo to 1 ml and transferred onto
a silica column (5 · 3.5 cm) with hexane/CH2Cl2 (3/2, v/v).
Three bands were isolated in the order of elution: wide yel-
low band H4Ru4(CO)12; wide brown band H4Ru4
(CO)10(l,j2-Ph2P(2-C5H4N)) (3) (37.9 mg, 0.040 mmol,
39%), pale-red narrow band of H3Ru4(CO)10(l3,
j2-PPh(2-C5H4N)) (4) (5.8 mg, 0.007 mmol, 7%).
(2) IR (CH2Cl2, cmꢀ1): m(CO) 2081m, 2051vs, 2025s,
1998m, 1978m, 1946sh. 1H NMR (300 MHz, CDCl3,
25 ꢀC) d = 9.04 (d, J = 5.5 Hz, 1H, H6 Py), 7.73 (dd,
J = 5.5, 3.7 Hz, 1H, H4 Py), 7.05 (m, J = 6.4 Hz, 1H, H5
Py), 6.34 (dd, J = 7.3, 3.7 Hz, 1H, H3 Py), 7.5–7.4 (m,
5H, Ph–P), ꢀ18.1 (d, JP–H = 14.3 Hz, 1H, OsH). 31P
{1H} NMR (121 MHz, CDCl3, 25 ꢀC) d = 19.2 (1JOs–P
= 115 Hz). MS (m/z): M+ 1013(Os3 = 570) followed by
fragmentation of four COs: (M+ ꢀ nCO), n = 1–4. Anal.
calcd. for C20H10N1O9Os3P1 (1009.96): C, 23.78; H, 1.00;
N, 1.39. Found: C, 24.48; H, 1.01; N, 1.30%. Single crystals
of 2 suitable for an X-ray analysis were grown from hexane
at 2 ꢀC.
(3): IR (hexane, cmꢀ1), m(CO) 2085w, 2081s, 2067s,
2058m, 2051m, 2043w, 2028s, 2023s, 2013m, 2009m,
1987m, 1945w. 1H NMR (300 MHz, CDCl3, ꢀ30 ꢀC)
d = 9.14 (d, J = 5.7 Hz, 1H, Py), 7.05 (m, 2H, Py), 6.30
(dd, J = 6.5, 4.5 Hz, 1H, Py), 7.34–7.75 (m, 10H, Ph),
ꢀ14.47 (s, 1H, H(01)), ꢀ16.17 (d, JP–H = 21.7 Hz, 1H,
H(04)), ꢀ16.31 (d, JP–H = 17.2 Hz, 1H, H(03)), ꢀ23.15 (s,
1H, H(02)). 31P{1H} NMR (121 MHz, CDCl3, 25 ꢀC)
d = 25.5 (s). MS-FAB+ (m/z): 951 (M+) (calc 951), [M+–
nCO], n = 1, 3, 4, 5, 6. Anal calc for 3 + 1/2 C6H14:
C30H25NO10PRu4 C, 36.22; H, 2.53; N, 1.43%. Found: C,
36.46; H, 2.64; N, 1.51%.
4.3. Reaction of the Os3(CO)10(l,j2-Ph2P(2-C5H4N))
cluster with dihydrogen
Os3(CO)10(l,j2-Ph2P(2-C5H4N) (31.1 mg, 0.030 mmol)
was dissolved in octane (30 ml) and H2 was bubbled
through the reaction mixture under reflux for 24 h. The

V.I. Ponomarenko et al. / Journal of Organometallic Chemistry 691 (2006) 111–121
119
(4): IR (m(CO), hexane, cmꢀ1) 2085m, 2081w, 2067w,
2058w, 2051s, 2028m, 2023s, 2014s, 1993m, 1987m,
1945w. The signals of two (major and minor) isomers were
using the SHELXS-97 program (1, 3) with the WinGX graph-
ical user interface [59–61]. An empirical absorption correc-
tion based on equivalent reflections was applied to all data
(SADABS v. 2.10 for 1 and XPREP in SHELXTL v. 6.14 for 2, 3,
4) [62,63]. The ratio of minimum to maximum transmis-
sions were 0.4675, 0.4040, and 0.8420 respectively for 1, 2
and 3. Structural refinements were carried out with
SHELXL-97 [60]. Hydrides in 1 were located from the differ-
ence Fourier map but were not refined. The location of the
hydride hydrogen (H01) in 2 was determined by XHYDEX
program [49]. In 3 the hydride hydrogens were located
from a difference Fourier map and refined with fixed
Uiso = 0.05. In 4 the hydrides were placed in an idealized
position with XHYDEX program [49]. All other hydrogens
were placed in idealized positions and constrained to ride
1
found in the H and 31P spectra of 4.
Major isomer. 1H NMR (300 MHz, CDCl3, 223 K)
d = 8.60 (d, J = 5.15 Hz, 1H, Py), 7.65–7.55 (m, 5H, Ph),
7.50 (d, J = 6.30 Hz, 1H, Py), 7.27 (t, J = 6.40 Hz, 1H,
Py), 6.27 (d, J = 7.59 Hz, 1H, Py), ꢀ16.94 (d,
2JPꢀH = 8.8 Hz, 2H, H(01) + H(03)), ꢀ22.74 (s, 1H,
H(02)). 31P NMR (121 MHz, CDCl3, 298 K) d = 118.1
(s). Minor isomer. 1H NMR (300 MHz, CDCl3, 223 K)
d = 8.46 (d, J = 5.32 Hz, 1H, Py), 7.65–7.55 (m, 5H,
Ph + 1 H Py), 7.16 (t, J = 6.40 Hz, 1H, Py), 6.27 (d,
J = 7.59 Hz, 1H, Py), ꢀ17.68 (d, J = 17.7 Hz, 1H,
H(01)), ꢀ18.10 (d, J = 10.3 Hz, 1H, H(03)), ꢀ23.50 (d,
J = 3.1 Hz, 1H, H(02)). 31P NMR (121 MHz, CDCl3,
298 K) d = 122.6 (s). MS-FAB + (m/z): 874 (M+) (calc.
874), [M+ ꢀ nCO], n = 1–3. Anal. calc. for C21H12NO10-
PRu4: C, 28.87; H, 1.38; N, 1.60. Found: C, 27.44; H,
1.56, N, 1.54%. Single crystals of 3 and 4 were obtained
by slow diffusion of hexane into CH2Cl2 solutions of these
clusters at +5 ꢀC.
Table 2
˚
Selected bond lengths (A) and angles (ꢀ) for 1 and 2
1
2
Os(1)–Os(2)
Os(1)–Os(3)
Os(2)–Os(3)
Os(1)–C(2)
Os(2)–C(5)
Os(1)–N(1)
Os(2)–P(1)
Os(3)–P(1)
N(1)–C(15)
P(1)–C(15)
2.8354(4)
2.9992(5)
2.9539(4)
1.899(11)
1.930(8)
2.158(7)
2.352(2)
2.337(2)
1.340(10)
1.810(8)
2.8528(5)
2.8384(5)
2.9289(5)
1.892(11)
1.936(12)
2.187(9)
2.342(3)
2.345(3)
1.354(13)
1.817(10)
4.6. X-ray structure determinations
The crystals of 1 and 2 were immersed in perfluoro-
polyether, mounted in a cryo-loops and measured at
100 K temperature. The X-ray diffraction data were col-
lected with a Nonius KappaCCD diffractometer using
Os(1)–Os(2)–Os(3)
Os(1)–Os(3)–Os(2)
Os(1)–N(1)–C(15)
Os(2)–P(1)–C(15)
Os(3)–P(1)–C(15)
Os(2)–P(1)–Os(3)
N(1)–C(15)–P(1)
62.364(11)
56.880(10)
58.786(13)
59.268(13)
˚
Mo Ka radiation (k = 0.71073 A). The EvalCCD (1) or
121.2(5)
110.6(3)
116.3(2)
78.09(5)
114.2(6)
119.7(7)
115.3(3)
113.8(3)
77.33(8)
112.4(7)
Denzo-Scalepack [57,58] (2, 3, 4) programs packages were
used for cell refinements and data reductions. The struc-
tures were solved either by Patterson heavy atom method
using the DIRDIF-99 program (2, 4) or by direct methods
Table 1
Crystallographic data for 1–4
1
2
3
4
Empirical formula
Fw
C
25H16NO8Os3P
C20H10NO9Os3P
1009.86
100(2)
0.71073
Orthorhombic
Pbca
C30H25NO10PRu4
994.76
120(2)
0.71073
Monoclinic
P21/c
12.19320(10)
14.4381(2)
20.5163(5)
90
92.3195(5)
90
3608.87(11)
4
1.831
1.737
C21H12NO10PRu4
873.57
120(2)
0.71073
Triclinic
1059.96
100(2)
0.71073
Monoclinic
P21/c
9.9993(8)
16.7951(14)
16.2898(11)
90
96.854(7)
90
Temperature (K)
˚
k (A)
Crystal system
Space group
ꢀ
P1
˚
a (A)
15.8704(3)
16.0803(3)
18.5394(4)
90
90
90
4731.27(16)
8
2.835
10.3823(1)
10.5342(1)
12.9826(6)
76.6072(7)
69.4710(7)
75.1912(7)
1269.65(6)
2
˚
b (A)
˚
c (A)
a (ꢀ)
b (ꢀ)
c (ꢀ)
3
˚
V (A )
2716.1(4)
4
2.592
Z
qcalc. (g/cm3)
2.285
2.452
l(MoKa) (mmꢀ1
)
14.106
16.192
Reflns collected/unique
Rint
25455/5524
0.0486
0.0312
35014/4643
0.0514
0.0355
41460/6875
0.0334
0.0247
9519/4920
0.0117
0.0204
a
R1 (I P 2r)
b
wR2 (I P 2r)
0.0467
0.0803
0.0653
0.0625
P
P
a
R1 = ||Fo| ꢀ |Fc||/ ||Fo|.
P
P
2
2 1=2
b
wR2 ¼ ½ ½wðF 2o ꢀ F c2Þ ꢁ= ½wðF 2oÞ ꢁꢁ
.

120
V.I. Ponomarenko et al. / Journal of Organometallic Chemistry 691 (2006) 111–121
Table 3
[9] A.J. Deeming, M.B. Smith, J. Chem. Soc., Chem. Commun. (1993)
844.
˚
Selected bond lengths (A) and angles (ꢀ) for 3 and 4
[10] A.J. Deeming, M.B. Smith, J. Chem. Soc., Dalton Trans. (1993) 3383.
[11] S.P. Tunik, I.O. Koshevoy, A.J. Poe, D.H. Farrar, E. Nordlander,
M. Haukka, T.A. Pakkanen, Dalton Trans. (2003) 2457.
[12] N. Lugan, G. Lavigne, J.J. Bonnet, Inorg. Chem. 25 (1986) 7.
[13] N. Lugan, G. Lavigne, J.J. Bonnet, Inorg. Chem. 26 (1987) 585.
[14] A.J. Deeming, M.B. Smith, J. Chem. Soc., Dalton Trans. (1993)
2041.
[15] N. Lugan, G. Lavigne, J.J. Bonnet, R. Reau, D. Neibecker, I.
Tkatchenko, J. Am. Chem. Soc. 110 (1988) 5369.
[16] N. Lugan, P.L. Fabre, D. de Montauzon, G. Lavigne, J.J. Bonnet,
J.Y. Saillard, J.F. Halet, Inorg. Chem. 32 (1993) 1363.
[17] M.P. Cifuentes, M.G. Humphrey, B.W. Skelton, A.H. White, J.
Organomet. Chem. 513 (1996) 201.
3
4
Ru(1)–Ru(2)
Ru(1)–Ru(3)
Ru(1)–Ru(4)
Ru(2)–Ru(3)
Ru(2)–Ru(4)
Ru(3)–Ru(4)
Ru(1)–N(1)
Ru(2)–P(1)
Ru(3)–P(1)
P(1)–C(32)
2.7703(4)
2.9553(4)
2.9228(4)
2.9840(4)
2.8975(4)
2.7784(4)
2.169(3)
2.9385(3)
2.9358(3)
2.9772(3)
2.8712(3)
2.7398(3)
2.7512(3)
2.173(2)
2.2872(8)
2.3070(8)
1.831(3)
2.2871(9)
1.840(3)
1.356(4)
N(1)–C(32)
1.361(4)
[18] A.A. Cherkas, J.F. Corrigan, S. Doherty, S.A. MacLaughlin, F. van
Gastel, N.J. Taylor, A.J. Carty, Inorg. Chem. 32 (1993) 1662.
[19] F. Van Gastel, A.J. Carty, M.A. Pellinghelli, A. Tiripicchio, E.
Sappa, J. Organomet. Chem. 385 (1990) C50.
[20] M. Lanfranchi, A. Tiripicchio, E. Sappa, A.J. Carty, J. Chem. Soc.,
Dalton Trans. (1986) 2737.
P(1)–C(32)–N(1)
C(32)–N(1)–Ru(1)
C(32)–P(1)–Ru(2)
C(32)–P(1)–Ru(3)
116.0(2)
121.8(2)
114.49(11)
120.0(2)
120.0(2)
114.26(10)
114.04(10)
on their parent atom. In the structure 3, half a molecule of
hexane was found in the asymmetric unit. The solvent mol-
ecules were completely disordered around a center of sym-
metry and the carbons were refined only isotropically with
equal displacement parameter. Because of the disorder,
hydrogens of the solvent molecule were omitted. The crys-
tallographic data are summarized in Table 1, selected bond
lengths and angles are given in Tables 2 and 3.
[21] J.-C. Choi, T. Sakakura, J. Am. Chem. Soc. 126 (2003) 7762.
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The authors gratefully acknowledge financial support
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Nordic Council of Ministers (to T.S.P.); Russian Founda-
tion for Basic Research, Grant 05-03-33266 and Humboldt
Foundation, Grant V-RKS-RUS/1074525 (for E.V.G.) We
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