Synthesis and structural characterization of mesitylphosphinidene-capped ruthenium and osmium clusters

Article abstract of DOI:10.1016/j.jorganchem.2005.10.011

Thermal reaction of [Ru₃(CO)₁₂] with PH ₂Mes (Mes = mesityl) in refluxing toluene afforded mesitylphosphinidene-capped ruthenium carbonyl clusters, [Ru ₃(CO)₉(μ-H)₂(μ₃-PMes)] (1), [Ru₃(CO)₈(PH₂Mes)(μ-H)₂(μ ₃-PMes)] (2), [Ru₃(CO)₉(μ ₃-PMes)₂] (3), [Ru₄(CO) ₁₀(μ-CO)(μ₄-PMes)₂] (4), and [Ru ₅(CO)₁₀H₂(μ₄-PMes)(μ ₃-PMes)₂] (5). All products were fully characterized and structurally confirmed by X-ray crystal structure analysis. Complexes 2-4 were also obtained in high yields by stepwise reaction starting from 1. Fluxional behavior of carbonyl groups was observed in case of 4. Complex 5 reveals a new type of skeletal structure, bicapped-octahedron having μ₃- and μ₄-phosphinidene ligands at the capping positions. Similar reaction of [Os₃(CO)₁₂] with PH₂Mes yielded a phosphido-bridged osmium cluster [Os₃(CO) ₁₀(μ-H)(μ-PHMes)] (6) and a phosphinidene-capped cluster [Os₃(CO)₉(μ-H)₂(μ₃-PMes)] (7).

Full text of DOI:10.1016/j.jorganchem.2005.10.011

Journal of Organometallic Chemistry 691 (2006) 726–736
www.elsevier.com/locate/jorganchem
Synthesis and structural characterization of
mesitylphosphinidene-capped ruthenium and osmium clusters
*
*
Taeko Kakizawa, Hisako Hashimoto , Hiromi Tobita
Department of Chemistry, Graduate School of Science, Tohoku University, Aoba-ku, Sendai, Miyagi 980-8578, Japan
Received 3 June 2005; accepted 4 October 2005
Available online 15 November 2005
Abstract
Thermal reaction of [Ru3(CO)12] with PH2Mes (Mes = mesityl) in refluxing toluene afforded mesitylphosphinidene-capped ruthenium
carbonyl clusters, [Ru3(CO)9(l-H)2(l3-PMes)] (1), [Ru3(CO)8(PH2Mes)(l-H)2(l3-PMes)] (2), [Ru3(CO)9(l3-PMes)2] (3), [Ru4(CO)10(l-
CO)(l4-PMes)2] (4), and [Ru5(CO)10H2(l4-PMes)(l3-PMes)2] (5). All products were fully characterized and structurally confirmed by
X-ray crystal structure analysis. Complexes 2–4 were also obtained in high yields by stepwise reaction starting from 1. Fluxional behavior
of carbonyl groups was observed in case of 4. Complex 5 reveals a new type of skeletal structure, bicapped-octahedron having l3- and
l4-phosphinidene ligands at the capping positions. Similar reaction of [Os3(CO)12] with PH2Mes yielded a phosphido-bridged osmium
cluster [Os3(CO)10(l-H)(l-PHMes)] (6) and a phosphinidene-capped cluster [Os3(CO)9(l-H)2(l3-PMes)] (7).
ꢀ 2005 Elsevier B.V. All rights reserved.
Keywords: Cluster; Mesitylphosphine; Phosphinidene ligand; X-ray structure study
1. Introduction
However, since the variety of primary phosphines used for
bridging-ligand precursors is still limited, the research in
this area is yet at the early stage of development.
Phosphinidene is a good tool for assembling metal frag-
ments to build up metal clusters, since it can work as a four-
electron donor and is capable of bridging two or more metal
atoms. This interesting ligand can be conveniently gener-
ated from primary phosphines through their coordination
to metal and the following dehydrogenation [1]. Huttner
et al. and some other groups [2] have proved that thermol-
ysis of [M3(CO)12] (M = Fe, Ru, and Os) in the presence of
a primary phosphine gives various Group 8 metal clusters
bridged by phosphinidene ligands. Particularly, Smit et al.
[3] successfully synthesized a wide range of ruthenium clus-
ters with higher nuclearity containing phenylphosphinidene
ligands, i.e., [Ru4(CO)10(l-CO)(l4-PPh)2], [Ru4(CO)8(l-
PPhH)2(l4-PPh)2], [Ru5(CO)15(l4-PPh)], [Ru6(CO)12(l4-
PPh)3(l3-PPh)2], and [Ru6(CO)12(l4-PPh)2(l3-PPh)2], etc.
In the chemistry of phosphinidene-capped metal clus-
ters, the substituent on phosphorus can be a critical factor
for growth of the cluster framework. In this work, we per-
formed cluster syntheses of ruthenium and osmium with
use of mesitylphosphine PH2Mes (Mes = 2,4,6-trimethyl-
phenyl = mesityl) as a precursor of the bridging unit [4].
Although a few examples of mesitylphosphinidene-capped
carbonyl clusters of iron are known (i.e., [Fe3(CO)9-
(l-CO)(l3-PMes)] [5] and [Fe3(CO)9(l3-PMes)2] [6]), no
examples of mesitylphosphinidene-ruthenium or -osmium
clusters have been reported. The influence of the bulky
mesityl group upon the skeletal structure of the clusters is
of interest. In fact, our trial gave a ruthenium compound
having a new type of core structure besides species with
known frameworks. This paper describes the full character-
ization of seven mesitylphosphinidene-capped ruthenium
and osmium clusters. Stepwise and high-yield transforma-
tion reactions of obtained complexes are also described.
*
Corresponding author.
E-mail address: hhashimoto@mail.tains.tohoku.ac.jp (H. Hashimoto).
0022-328X/$ - see front matter ꢀ 2005 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2005.10.011

T. Kakizawa et al. / Journal of Organometallic Chemistry 691 (2006) 726–736
727
2. Results and discussion
produced complexes 1, 3, 4, and 5 in 12%, 13%, 7%, and
33% yields, respectively, with unidentified oily products.
When a reaction was carried out at lower temperature,
i.e., in refluxing hexane, complex 2 was obtained in the
yield higher than any other products [1 (11%), 2 (29%), 3
(8%), 4 (4%), and 5 (5%)].
2.1. Synthesis and structures of ruthenium clusters 1–5
Heating a toluene solution containing PH2Mes and
[Ru3(CO)12] in a 1:1 molar ratio produced a mixture of tri-
ruthenium complexes [Ru3(CO)9(l-H)2(l3-PMes)] (1),
[Ru3(CO)8(PH2Mes)(l-H)2(l3-PMes)] (2), and [Ru3(CO)9-
(l3-PMes)2] (3), a tetraruthenium complex [Ru4(CO)10-
(l-CO)(l4-PMes)2] (4), and a pentaruthenium cluster
[Ru5(CO)10H2(l4-PMes)(l3-PMes)2] (5) (Scheme 1). The
formation ratio of these products slightly depends on the
reaction conditions. When the reaction was carried out in
refluxing toluene for 30 min, complexes 1, 2, 3, 4, and 5
were obtained in 27%, 8%, 15%, 2%, and 17% yields,
respectively. The formation of clusters 4 and 5 is favored
under more forced conditions. Thus, overnight refluxing
of the reaction mixture gave complexes 1, 3, 4, and 5 in
26%, 14%, 10%, and 31% yields, respectively. Complex 2
was not obtained under this condition. The use of twofold
molar amount of PH2Mes under the same condition
In a field of the synthesis of metal clusters, it is still dif-
ficult to obtain a desired cluster selectively in high yield
and the formation mechanism of the products is not clear
in many cases. Therefore, to find the ways to build up a
target cluster efficiently is still one of the important
research topics in this field. Although complexes 2–4 were
obtained in only low yields from the above reactions, we
found that they could be prepared selectively in high
yields from complex 1 by the stepwise reactions shown
in Scheme 2. Thus, complex 2 was obtained by the reac-
tion of 1 with PH2Mes in refluxing hexane in 78% yield.
Overnight refluxing of a toluene solution of 2 under CO
atmosphere gave 3 in 56% yield. Complex 3 reacted with
[Ru3(CO)12] in refluxing toluene to form tetraruthenium
cluster 4 in 78% yield.
hexane or toluene reflux
[Ru3(CO)12
]
+
PH2Mes
CO
P
Ru
Ru
Ru
Ru
Ru
H
P
H
Ru
+
+
P
Ru
P
Ru
H
Ru
H
P
H
H
1
3
2
P
P
Ru
Ru
Ru
Ru
Ru
Ru
Ru
P
Ru
+
+
P
P
Ru
4
5
Scheme 1. Reaction of [Ru3(CO)12] with PH2Mes (hydride ligands on cluster 5 are not located).

728
T. Kakizawa et al. / Journal of Organometallic Chemistry 691 (2006) 726–736
+ PH2Mes
+ 1/3 [Ru3(CO)12]
+ CO
4
2
1
3
toluene reflux
– 2CO
hexane reflux
– CO
toluene reflux
– 2H2
Scheme 2. Stepwise reactions starting from complex 1.
Although we have not yet established the high-yield syn-
caps a ruthenium triangle. Two hydrido ligands bridge over
Ru(1)–Ru(2) and Ru(1)–Ru(3) bonds. These Ru–Ru bonds
thesis of the new cluster 5, these results provide good evi-
dences of the formation pathways for clusters 2–4 by the
reaction of [Ru3(CO)12] with PH2Mes. Formation of 1
can be rationalized by the coordination of mesitylphos-
phine and subsequent intramolecular oxidative addition
of two P–H bonds accompanied by dissociation of overall
three CO ligands [1]. After that, cluster 2 can produce
under relatively mild conditions by a simple replacement
of a CO ligand of 1 by the second mesitylphosphine. In
refluxing toluene, 2 undergoes reductive elimination of
H2, intramolecular oxidative addition of two P–H bonds
of the mesitylphosphine ligand, another reductive elimina-
tion of H2, and final recoordination of a CO to afford clus-
ter 3. Then, 3 slowly reacts with Ru(CO)4 generated from
Ru3(CO)12 and subsequent dissociation of two CO ligands
gives cluster 4.
˚
(Ru(1)–Ru(2) 2.9203(4) A and Ru(1)–Ru(3) 2.9424(4)
˚
A) are slightly longer than the Ru(2)–Ru(3) bond
˚
(2.7990(4) A) that has no bridging hydrogen. Complex 1
is classified into a nido-type cluster with four vertices and
is closely related to the known phosphinidene-bridged clus-
ters [Ru3(CO)9(l-H)2(l3-PR)] (R = Ph, p-CH3OC6H4, Cy,
etc.) [2b,2c,7]. In addition, the existence of equivalent two
bridging hydrogen atoms were confirmed by the 1H
NMR spectrum, which shows a single resonance at
ꢀ19.12 ppm as a doublet due to the coupling with the
phosphorus atom of the phosphinidene ligand.
An ORTEP plot of 2 is exhibited in Fig. 2. A l3-PMes
group caps the basal triangle composed of three ruthenium
atoms, one of which is coordinated with a PH2Mes ligand.
The 31P NMR spectrum shows the signals of l3-phosphi-
nidene and terminal PH2Mes ligands at moderately low
field (233.6 ppm) and very high field (ꢀ99.2 ppm), respec-
The molecular structures of complexes 1–5 were con-
firmed by X-ray crystallography. An ORTEP diagram of
triruthenium complex 1 is shown in Fig. 1. Cluster 1 adopts
a trigonal pyramidal geometry in which a l3-PMes ligand
1
tively. In the H NMR spectrum, the l-hydride resonance
Fig. 2. Molecular structure of [Ru3(CO)8(PH2Mes)(l-H)2(l3-PMes)] (2).
Thermal ellipsoids are drawn at the 50% probability. Selected bond
˚
Fig. 1. Molecular structure of [Ru3(CO)9(l-H)2(l3-PMes)] (1). Thermal
ellipsoids are drawn at the 50% probability. Selected bond lengths (A)
lengths (A) and angles (ꢁ): Ru(1)–Ru(2) = 2.9516(6), Ru(1)–
˚
Ru(3) = 2.9286(6), Ru(2)–Ru(3) = 2.7986(6), Ru(1)–P(1) = 2.3210(12),
and angles (ꢁ): Ru(1)–Ru(2) = 2.9426(4), Ru(1)–Ru(3) = 2.9207(4),
Ru(2)–Ru(3) = 2.7993(4), Ru(1)–P = 2.3446(9), Ru(2)–P = 2.3240(9),
Ru(3)–P = 2.3152(9); Ru(2)–Ru(1)–Ru(3) = 57.034(10), Ru(1)–Ru(2)–
Ru(3) = 61.090(10), Ru(2)–Ru(3)–Ru(1) = 61.876(10), Ru(1)–P–Ru(2) =
78.14(3), Ru(1)–P–Ru(3) = 77.62(3), Ru(2)–P–Ru(3) = 74.23(3).
Ru(2)–P(1) = 2.3123(12), Ru(3)–P(1) = 2.3344(12), Ru(1)–P(2) = 2.3496(14);
Ru(2)–Ru(1)–Ru(3) = 56.839(13),
Ru(1)–Ru(2)–Ru(3) =
61.17(2),
Ru(2)–Ru(3)–Ru(1) = 61.994(14), Ru(1)–P(1)–Ru(2) = 79.14(4), Ru(1)–
P(1)–Ru(3) = 77.96(4), Ru(2)–P(1)–Ru(3) = 74.07(4), P(1)–Ru(1)–P(2) =
158.25(5), Ru(1)–P(2)–C(18) = 118.3(2).

T. Kakizawa et al. / Journal of Organometallic Chemistry 691 (2006) 726–736
729
of 2 appears at ꢀ18.89 ppm as a virtual triplet of triplet,
coupled with two phosphorus nuclei (JPH = 15.3 Hz) and
two protons on the PH2Mes ligand (JHH = 1.8 Hz). Powell
also reported the appearance of a triplet of triplet for the
hydride signal of a related PPh complex [Ru3(CO)8(PH2Ph)-
(l-H)2(l-PPh)] [8].
The molecular structure of complex 3 is depicted in
Fig. 3. Complex 3 reveals a distorted square pyramidal
geometry with the basal plane composed of two ruthenium
and two phosphorus atoms, and a Ru(CO)3 fragment at
the apical position. Two aromatic rings of the mesityl
groups are nearly coplanar to each other and adopt a
twisted arrangement with respect to the basal plane. The
˚
Ru(1)–Ru(2) bond (2.9289(8) A) is slightly longer than
˚
the Ru(1)–Ru(3) bond (2.8092(8) A), probably due to the
steric repulsion among two o-methyl groups (C(16) and
C(27)) and carbonyl ligands on the Ru(1) and Ru(2) atoms.
Such a steric repulsion can cause a restricted rotation of the
mesityl groups, and indeed the 1H NMR spectrum displays
two resonances for inequivalent o-methyl groups at 2.67
and 2.68 ppm at room temperature.
Fig. 4 shows the molecular structure of tetraruthenium
complex 4. Cluster 4 has a closo octahedral framework.
Both sides of the square Ru4 plane are capped with two
l4-phosphinidene ligands. Among eleven carbonyl groups,
one (C(9)O(9)) bridges over the Ru(3)–Ru(4) bond, while
the other ten carbonyl ligands are bound to the four ruthe-
nium atoms in essentially terminal fashions. The IR spec-
trum clearly shows the existence of a bridging carbonyl
with a mCO band at 1809 cmꢀ1 in addition to five mCO bands
for terminal carbonyl ligands. In more detailed analysis,
two of the terminal carbonyl ligands (C(1)O(1) and
C(4)O(4)) slightly tilt toward the adjacent ruthenium atoms
(Ru(4) and Ru(3)) to take a semi bridging coordination
mode. This geometry implies that the semi bridging CO
ligands can easily migrate into the bridging positions. In
fact, the 13C NMR spectrum of 4 in CD2Cl2 shows only
Fig. 4. Molecular structure of [Ru4(CO)10(l-CO)(l4-PMes)2] (4). Thermal
ellipsoids are drawn at the 50% probability. Selected bond lengths (A)
˚
and angles (ꢁ): Ru(1)–Ru(2) = 2.8092(8), Ru(2)–Ru(3) = 2.8976(8),
Ru(3)–Ru(4) = 2.7107(8), Ru(4)–Ru(1) = 2.8976(8), Ru(1)–P(1) = 2.412(2),
Ru(2)–P(1) = 2.416(2), Ru(3)–P(1) = 2.489(2), Ru(4)–P(1) = 2.548(2);
Ru(1)–Ru(2)–Ru(3) = 89.00(2), Ru(2)–Ru(3)–Ru(4) = 90.95(2), Ru(1)–
P(1)–Ru(2) = 71.16(6), Ru(1)–P(1)–Ru(4) = 71.44(5), Ru(3)–P(1)–Ru(4) =
65.11(5).
one broad signal at 202.3 ppm for the eleven CO ligands at
room temperature. Thus, all carbonyl groups are exchanging
their positions around the ruthenium four-membered ring
˚
Fig. 3. Molecular structure of [Ru3(CO)9(l3-PMes)2] (3). Thermal ellipsoids are drawn at the 50% probability. Selected bond lengths (A) and angles (ꢁ):
Ru(1)–Ru(2) = 2.9289(8), Ru(1)–Ru(3) = 2.8092(8), Ru(1)–P(1) = 2.370(2), Ru(2)–P(1) = 2.341(2), Ru(3)–P(1) = 2.357(2); Ru(2)–Ru(1)–Ru(3) =
82.09(2), Ru(2)–P(1)–Ru(3) = 106.71(7), Ru(2)–P(2)–Ru(3) = 106.31(7), P(1)–Ru(1)–P(2) = 71.34(6), P(1)–Ru(2)–P(2) = 72.70(6), P(1)–Ru(3)–P(2) =
71.95(6).

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T. Kakizawa et al. / Journal of Organometallic Chemistry 691 (2006) 726–736
faster than the NMR time scale, probably with a merry-go-
round process (Scheme 3) [3,9]. At ꢀ80 ꢁC, the CO signal
splits into four signals (d 254.6, 201.0, 195.7, and
195.1 ppm) in the intensity ratio of 1:2:4:4. The same type
of complex [Ru4(CO)10(l-CO)(l4-PPh)2] reported by Smit
et al. [3] also shows a fluxional behavior. But, in this com-
pound, the scrambling of CO is so fast that the CO reso-
nance does not decoalesce even at ꢀ114 ꢁC. The slower
CO scrambling observed in complex 4 is likely to be caused
by the steric hindrance of bulky mesityl groups, which dis-
turbs the merry-go-round process.
Ru6 arrangement, [Ru6(CO)12(l4-PPh)3(l3-PPh)2], [Ru6-
(CO)12(l4-PPh)2(l3-PPh)2], [Ru6(CO)12H2(l4-PPh)2(l3-
PPh)2], etc. [2,3,10]. Although the reaction pathway leading
to cluster 5 is yet unexplainable, it is likely that sterically
congested mesityl groups play a key role for the formation
of its tightly closed novel framework.
2.2. Synthesis and structures of osmium clusters 6 and 7
In contrast to the ruthenium system, only two products
were formed by the thermal reaction of [Os3(CO)12] with
PH2Mes in refluxing toluene. Triosmium complexes
[Os3(CO)10(l-H)(l-PHMes)] (6) and [Os3(CO)9(l-H)2(l3-
PMes)] (7) were obtained in 19% and 40% yields, respec-
tively (Eq. (1)). Wheatley et al. [2b] have reported a similar
thermal reaction between [Os3(CO)12] and PH2Ph produc-
ing the phenyl-substituted derivatives, [Os3(CO)10(l-H)(l-
PHPh)] and [Os3(CO)9(l-H)2(l3-PPh)]. They described
that phosphido-bridged complex [Os3(CO)10(l-H)(l-
PHPh)] transformed into phosphinidene-capped cluster
[Os3(CO)9(l-H)2(l3-PPh)] via loss of CO ligand on heating.
Similar to this, refluxing of a toluene solution of 6 gave 7 in
84% yield (Eq. (2)).
Fig. 5 depicts the result of X ray structural analysis of
pentaruthenium cluster 5. This compound has a bicapp-
ped-octahedral core. The five ruthenium atoms constitute
a square pyramidal framework and each ruthenium atom
bears two carbonyl ligands. The basal plane of the ruthe-
nium pyramid is capped with a l4-PMes ligand, and two
triangular faces are capped with l3-PMes units. In the pen-
taruthenium pyramid, Ru–Ru bonds from the apical Ru(1)
atom to the four basal ruthenium atoms (2.8618(8)–
˚
2.9197(8) A) are longer than the remaining Ru–Ru bonds
˚
in the basal plane (2.7915(8)–2.8896(8) A). Although the
positions of hydrido ligands attached to the ruthenium
framework could not be determined in the crystal struc-
tural analysis, the existence of them were confirmed by
1H NMR spectroscopy. A broad signal observed at
ꢀ16.80 ppm (2H intensity) in the 1H NMR spectrum
clearly indicates that 5 has two bridging hydrido ligands.
The 1H NMR spectrum of 5 also shows two kinds of mesi-
tyl groups with an integral ratio of 2:1, which are in accord
with the solid state structure of 5.
A wide range of phosphinidene-bridged ruthenium car-
bonyl clusters has already been reported. Nonetheless,
complex 5 is the first example of the phosphinidene-
ruthenium cluster having a bicapped-octahedral skeletal
framework. Related clusters reported previously are
pseudo-octahedral pentaruthenium clusters, [Ru5(CO)15-
(l4-PPh)] and [Ru5(CO)13(l4-PPh)(l-PPh(OPrn))(l-H)], and
hexaruthenium clusters with a distorted trigonal prismatic
toluene
+
[Os3(CO)12
]
PH2Mes
reflux
overnight
H
P
P
Os
+
Os
H
Os
Os
H
Os
Os
H
CO
6
7
ð1Þ
ð2Þ
– CO
toluene reflux
6
7
O
C
OC
CO
CO
Ru
OC
Ru
OC
CO
CO
O
C
O
C
Ru
Ru
OC
CO
CO
Ru
OC
CO
CO
Ru
OC
OC
OC
OC
OC
OC
Ru
CO
Ru
OC
OC
CO
CO
CO
Ru
Ru
Ru
Ru
Ru
Ru
Ru
Ru
OC
CO
OC
CO
CO
C
O
OC
C
O
CO
OC
CO
OC
OC
CO
CO
C
O
Scheme 3. A plausible exchange process (merry-go-round process) of carbonyl groups in complex 4 (phosphinidene unites are omitted for clarity).

T. Kakizawa et al. / Journal of Organometallic Chemistry 691 (2006) 726–736
731
˚
Fig. 5. Molecular structure of [Ru5(CO)10H2(l4-PMes)(l3-PMes)2] (5). Thermal ellipsoids are drawn at the 50% probability. Selected bond lengths (A)
and angles (ꢁ): Ru(1)–Ru(2) = 2.9197(8), Ru(1)–Ru(3) = 2.8681(8), Ru(1)–Ru(4) = 2.8913(8), Ru(1)–Ru(5) = 2.9163(8), Ru(2)–Ru(3) = 2.8308(8), Ru(3)–
Ru(4) = 2.7915(8), Ru(4)–Ru(5) = 2.8296(8), Ru(2)–Ru(5) = 2.8896(8), Ru(1)–P(2) = 2.399(2), Ru(2)–P(2) = 2.272(2), Ru(2)–P(1) = 2.388(2); Ru(1)–
Ru(2)–Ru(3) = 59.81(2), Ru(1)–Ru(2)–Ru(5) = 60.26(2), Ru(2)–Ru(1)–Ru(3) = 58.56(2), Ru(2)–Ru(1)–Ru(5) = 59.36(2), Ru(2)–Ru(1)–Ru(4) = 87.31(2),
Ru(2)–Ru(3)–Ru(4) = 91.04(2), Ru(1)–P(2)–Ru(2) = 77.31(6), Ru(2)–P(2)–Ru(3) = 76.78(6), Ru(2)–P(1)–Ru(3) = 71.87(6), Ru(2)–P(1)–Ru(5) = 74.38(6).
The X-ray crystal structures of 6 and 7 are depicted in Figs. 6
and 7, respectively. Their structures closely resemble those of
the phenyl-substituted clusters [Os3(CO)10(l-H)(l-PHPh)]
and [Os3(CO)9(l-H)2(l3-PPh)], respectively. In complex 6,
one Os–Os edge of the osmium triangle is bridged by l-phos-
phido and l-hydrido ligands. The Os–Os bond bridged by
Fig. 6. Molecular structure of [Os3(CO)10(l-H)(l-PHMes)] (6). Thermal
ellipsoids are drawn at the 50% probability. Selected bond lengths (A) and
Fig. 7. Molecular structure of [Os3(CO)9(l-H)2(l3-PMes)] (7). Thermal
ellipsoids are drawn at the 50% probability. Selected bond lengths (A)
˚
˚
angles (ꢁ): Os(1)–Os(2) = 2.8879(6), Os(1)–Os(3) = 2.8983(6), Os(2)–Os(3) =
2.9387(6), Os(2)–P = 2.377(3), Os(3)–P = 2.383(3); Os(2)–Os(1)–Os(3) =
61.046(14), Os(1)–Os(2)–Os(3) = 59.65(2), Os(2)–Os(3)–Os(1) = 59.303(14),
Os(2)–P–Os(3) = 76.25(8), P–Os(2)–Os(1) = 84.38(7), P–Os(2)–Os(3) =
51.97(7), P–Os(3)–Os(1) = 84.04(6), P–Os(3)–Os(2) = 51.78(7).
and angles (ꢁ): Os(1)–Os(2) = 2.9647(5), Os(1)–Os(3) = 2.9478(5), Os(2)–
Os(3) = 2.8240(5), Os(1)–P = 2.369(2), Os(2)–P = 2.347(2), Os(3)–P =
2.342(2), Os(2)–Os(1)–Os(3) = 57.060(12), Os(1)–Os(2)–Os(3) = 61.168(12),
Os(2)–Os(3)–Os(1) = 61.772(12), Os(1)–P–Os(2) = 77.89(6), Os(1)–P–
Os(3) = 77.46(6), Os(2)–P–Os(3) = 74.06(6).

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T. Kakizawa et al. / Journal of Organometallic Chemistry 691 (2006) 726–736
˚
these ligands, i.e., Os(2)–Os(3) (2.9387(6) A), is slightly
longer than the other two Os–Os bonds (Os(1)–Os(2);
erenced to an 85% H3PO4 used as an external standard. IR
spectra were measured on a HORIBA FT-730 spectrome-
ter. Elemental analyses were performed at the Instrumental
Analysis Center for Chemistry, Tohoku University. Mesi-
tylphosphine were prepared according to the literature
method [11]. All other reagents were purchased and used
without further purification.
˚
2.8879(6) and Os(1)–Os(3); 2.8983(6) A, respectively). The
1H NMR spectrum of 6 shows the l-hydrido signal at
ꢀ18.61 ppm as a doublet of doublet coupled with the phos-
phorus atom (JPH = 19.0 Hz) and PH proton (JHH
=
4.5 Hz). The proton on the l-phosphido ligand resonates
at the characteristic low field, 7.82 ppm, as a doublet of dou-
blet (JPH = 413.4 Hz, JHH = 4.5 Hz).
4.2. Reaction of [Ru3(CO)12] and PH2Mes
Cluster 7 is virtually isostructural with its ruthenium
analogue 1. The mesitylphosphinidene ligand caps the
basal metal triangle and two hydride ligands bridge over
two of the Os–Os edges. In the osmium triangle, the bond
lengths between Os(1)–Os(2) and Os(1)–Os(3) (2.9681(5)
(a) A toluene (25 mL) solution of [Ru3(CO)12] (300 mg,
0.469 mmol) and PH2Mes (71 mg, 0.47 mmol) was refluxed
for 30 min. The color of the solution changed from orange
to red during the reaction. The reaction mixture was filtered
and celite (ca. 1 g) was added to the filtrate to adsorb the
products. After removal of solvent under reduced pressure,
the celite was subjected to a silica gel flash column
(3 · 10 cm). Initially, hexane was used to elute a known
orange complex [Ru4(l-H)4(CO)12] (50 mg), and following
three yellow fractions. Concentration of the yellow fractions
gave [Ru3(CO)9(l-H)2(l3-PMes)] (1) (88 mg, 0.12 mmol,
27%), [Ru3(CO)9(l3-PMes)2] (3) (30 mg, 0.035 mmol,
15%), and [Ru3(CO)8(PH2Mes)(l-H)2(l3-PMes)] (2) (15
mg, 0.018 mmol, 7.7%), respectively. Subsequently hex-
ane–toluene mixtures with increasing toluene content (up
to 4:1 ratio) were used to elute the forth and fifth fractions
colored red and violet, respectively. Concentration of the
red fraction and violet fraction afforded [Ru5(CO)10H2(l4-
PMes)(l3-PMes)2] (5) (32 mg, 0.026 mmol, 17%) and
[Ru4(CO)10(l-CO)(l4-PMes)2] (4) (5 mg, 0.005 mmol, 2%
yield), respectively.
˚
and 2.9585(5) A, respectively), which were bridged by the
hydrido ligands, are slightly longer than that of Os(2)–
˚
Os(3) (2.8243(5) A); the same tendency was also found in
the ruthenium analogue 1. The 1H NMR spectrum displays
the l-hydrido resonance at ꢀ20.84 ppm as a doublet cou-
pled with the phosphorus atom.
3. Conclusion
Mesitylphosphinidene-capped tri, tetra, and pentaruthe-
nium clusters 1–5 were synthesized by the thermal reaction
of [Ru3(CO)12] with PH2Mes and structurally character-
ized. Clusters 2–4 were obtained selectively in high yields
by stepwise reactions starting from 1. In the case of
[Ru4(CO)10(l-CO)(l4-PMes)2] (4), fluxional behavior
involving the migration of all carbonyl groups around
tetraruthenium atoms was observed. [Ru5(CO)10H2(l4-
PMes)(l3-PMes)2] (5) has a novel bicapped-octahedral
framework in which a square pyramidal core composed
of five Ru(CO)2 fragments is capped with one l4- and
two l3-mesitylphosphinidene units. Although the reaction
pathway for 5 is not clarified yet, bulky mesityl group is
likely to play an important role for the formation of its
tightly closed skeletal framework. In contrast with the
ruthenium system, the thermal reaction of [Os3(CO)12] with
PH2Mes exclusively afforded trinuclear complexes, i.e.,
phosphido-bridged complex [Os3(CO)10(l-H)(l-PHMes)]
(6) and mesitylphosphinidene-capped cluster [Os3(CO)9(l-
H)2(l3-PMes)] (7).
1: yellow platelets. 1H NMR (300 MHz, CD2Cl2): d
2
ꢀ19.12 (d, JPH = 15.0 Hz, 2H, l-H), 2.03 (s, 3H, p-CH3),
4
2.44 (s, 6H, o-CH3), 6.75 (d, JPH = 3.6 Hz, 2H, ArH). 31P
NMR (121.5 MHz, CD2Cl2): d 218.8 (t, JPH = 15.0 Hz).
13C NMR (75.5 MHz, CD2Cl2): d 21.2 (s, p-CH3), 26.7 (d,
Jpc = 12.1 Hz, o-CH3), 128.4 (d, Jpc = 19.6 Hz, ipso-
C6H2Me3), 132.2 (d, Jpc = 9.1 Hz, o-C6H2Me3), 141.7
(d, Jpc = 3.8 Hz, p-C6H2Me3), 142.8 (d, Jpc = 9.1 Hz,
m-C6H2Me3), 190.9, 198.0 (br, CO). IR mCO (KBr, cmꢀ1):
2106 (m), 2071 (s), 2042 (vs), 2005 (s), 1996(s), 1976(s).
Anal. Calc. for C18H13O9PRu3: C, 30.56; H, 1.85. Found:
C, 30.93; H, 2.01.
2: yellow prisms. 1H NMR (300 MHz, CD2Cl2): d
2
3
4. Experimental
ꢀ18.89 (tt, 2H, JPH = 15.3 Hz, JHH = 1.8 Hz, l-H),
2.09 (s, 3H, p-CH3), 2.20 (s, 3H, p-CH3), 2.36 (s, 6H,
1
4.1. General procedure
o-CH3), 2.66 (s, 6H, o-CH3), 5.67 (dm, 2H, JPH
=
4
355.2 Hz, PH), 6.88 (d, 2H, JPH = 3.6 Hz, ArH), 6.94 (d,
2H, 4JPH = 3.6 Hz, ArH). 31P NMR (121.5 MHz, CD2Cl2):
d 233.6 (dt, JPP = 113.6 Hz, JPH = 15.3 Hz, l-PMes),
ꢀ99.2 (dtt, JPH = 355.2 Hz, JPP = 113.6 Hz, JPH = 15.3
Hz, PH2Mes). 13C NMR (75.5 MHz, CD2Cl2): d 21.1 (d,
Jpc = 4.5 Hz), 21.7 (s), 21.8 (s), 26.6 (d, Jpc = 11.3 Hz)
(all for Me), 121.2 (s), 121.9 (s), 129.9 (d, Jpc = 7.6 Hz),
130.8 (d, Jpc = 8.3 Hz), 131.3 (s), 139.7 (d, Jpc = 8.3 Hz),
140.9 (br, m), 142.4 (d, Jpc = 9.1 Hz) (all for Ph), 191.0
(m), 196.6 (m), 200.5 (br), 201.1 (br) (all for CO). IR mCO
All reactions were performed under dry nitrogen atmo-
sphere, using standard Schlenk techniques. Toluene and
hexane were distilled from sodium-benzophenone ketyl just
before use. Dichloromethane was dried over calcium
1
hydride and purified by trap-to-trap distillation. H, 13C,
and 31P NMR spectra were recorded on a Bruker ARX
300 spectrometer or a Bruker AVANCE 300 instrument.
1H and 13C NMR chemical shifts were referenced to SiMe4
as the standard (d = 0). 31P NMR chemical shifts were ref-

T. Kakizawa et al. / Journal of Organometallic Chemistry 691 (2006) 726–736
733
(KBr, cmꢀ1): 2071 (m), 2032 (vs), 2009 (s), 1993 (s), 1973 (s)
1957 (s). Anal. Calc. for C26H26O8P2Ru3: C, 37.55; H, 3.15,
Found: C, 37.05; H, 3.38.
(d) When the reaction of [Ru3(CO)12] (200 mg,
0.312 mmol) with PH2Mes (49 mg, 0.32 mmol) was per-
formed in hexane (30 mL) under reflux overnight, a dark
orange solution was produced. The solution was worked
up by the procedure similar to that described in (a) to afford
[Ru4(l-H)4(CO)12] (52 mg), 1 (25 mg, 0.036 mmol, 11%), 3
(11 mg, 0.013 mmol, 7.8%), 2, (38 mg, 0.046 mmol, 29%), 5
(6 mg, 0.005 mmol, 5%), and 4 (7 mg, 0.007 mmol, 4%), in
this order.
3: yellow prisms. 1H NMR (300 MHz, CD2Cl2): d 2.20 (s,
6H, p-CH3), 2.67 (s, 6H, o-CH3), 2.68 (s, 6H, o-CH3), 6.87
(s, 2H, ArH), 6.88 (s, 2H, ArH). 31P NMR (121.5 MHz,
CD2Cl2): d 184.2 (s). 13C NMR (75.5 MHz, CD2Cl2): d
21.0 (s), 23.1 (br) 27.2 (t, Jpc = 6.8 Hz) (all for Me), 129.8
(br), 130.6 (br), 132.4 (s), 139.6 (s), 140.3 (t, Jpc = 7.6 Hz),
140.7 (br) (all for Ph), 193.3 (t, Jpc = 28.7 Hz), 199.6 (s),
200.8 (t, Jpc = 9.8 Hz) (all for CO). IR mCO (KBr, cmꢀ1):
2060 (s), 2048 (s), 2036 (s), 2009 (s), 1998 (vs), 1961(m).
Anal. Calc. for C27H22O9P2Ru3: C, 37.90; H, 2.59. Found:
C, 38.08; H, 2.35.
4.3. Reaction of [Ru3(CO)9(l-H)2(l3-PMes)] (1) with
PH2Mes
A hexane solution (15 mL) of [Ru3(CO)9(l-H)2(l3-
PMes)] (1) (33 mg, 0.047 mmol) and PH2Mes (10 mg,
0.066 mmol) was heated under reflux overnight. The yellow
solution was adsorbed on celite, and the solvent was
removed under reduced pressure. Flash chromatography
(hexane/toluene (5:1)) on silica gel (2 · 4 cm) gave a single
product characterized as [Ru3(CO)8(PH2Mes)(l-H)2(l3-
PMes)] (2) (30 mg, 0.036 mmol, 78%).
4: violet prisms. 1H NMR (300 MHz, CD2Cl2): d 2.02 (s,
6H, p-CH3), 2.26 (s, 12H, o-CH3), 6.60 (s, 4H, ArH). 31P
NMR (121.5 MHz, CD2Cl2): d 151.2 (s). 13C NMR
(75.5 MHz, CD2Cl2 at 296 K): d 20.7 (s, p-CH3), 24.0 (t,
JPC = 6.0 Hz, o-CH3), 124.6 (t, JPC = 13.4 Hz, ipso-
C6H2Me3), 130.9 (t, JPC = 3.8 Hz, m-C6H2Me3), 140.2 (t,
JPC = 4.5 Hz, o-C6H2Me3), 141.2 (s, p-C6H2Me3), 202.3
(br, CO); (at 193 K) 195.1 (br, CO), 195.7 (br, CO), 201.0
(br, CO), 254.6 (br, l-CO). IR mCO (KBr, cmꢀ1): 2075
(w), 2041 (s), 2026 (vs), 2006 (s), 1959 (s), 1809 (s). Anal.
Calc. for C29H22O11P3Ru4: C, 34.39; H, 2.19. Found: C,
34.45; H, 2.38.
4.4. Reaction of [Ru3(CO)8(PH2Mes)(l-H)2(l3-PMes)]
(2) with carbon monoxide
A toluene solution (20 mL) of [Ru3(CO)8(PH2Mes)(l-
H)2(l3-PMes)] (2) (30 mg, 0.036 mmol) were refluxed for
3 h under carbon monoxide atmosphere. The brown solu-
tion was adsorbed on celite, and the solvent was removed
under reduced pressure. Flash chromatography (hexane/
toluene (5:1)) on silica gel (2 · 4 cm) gave [Ru3(CO)9(l3-
PMes)2] (3) (17 mg, 0.020 mmol, 56%) from the first yellow
band. The second red band and third brown band afforded
unidentified powders (4 mg and 6 mg, respectively) after
evaporation.
5: red platelets. 1H NMR (300 MHz, CD2Cl2): d ꢀ16.80
(br s, 2H, l-H), 2.12 (s, 3H, p-CH3 of l4-PMes), 2.30 (s, 6H,
p-CH3 of l3-PMes), 2.68 (s, 12H, o-CH3 of l4-PMes), 2.79
(s, 6H, o-CH3 of l3-PMes), 6.80 (br s, 2H, l4-PC6H2Me3),
7.03 (br s, 6H, l3-PC6H2Me3). 31P NMR (121.5 MHz,
CD2Cl2): d 447.4–450.3 (m, l-P). 13C NMR (75.5 MHz,
CD2Cl2): d 21.1 (s), 21.3 (s), 25.9 (d, Jpc = 5.3 Hz), 29.7
(d, Jpc = 14.3 Hz) (all for Me), 131.1 (m), 131.8 (m), 139.3
(m), 141.2 (m), 141.8 (s), 142.2 (s), 143.45 (s) (all for Ph),
192.3 (br), 200.3 (br), 200.7 (br) (all for CO). IR mCO
(KBr, cmꢀ1): 2030 (s), 2019 (s), 2009 (vs), 1999 (s), 1972
(s), 1957 (m). Anal. Calc. for C37H35O10P3Ru5: C, 35.90;
H, 2.85. Found: C, 36.19; H, 3.19.
4.5. Reaction of [Ru3(CO)9(l3-PMes)2] (3) with
[Ru3(CO)12]
(b) A toluene (40 mL) solution of PH2Mes (142 mg,
0.933 mmol) and [Ru3(CO)3] (600 mg, 0.969 mmol) was
refluxed overnight. The color of the solution changed from
orange to dark brown. Chromatographic separation of the
resulting mixture in a manner analogous to that described
in (a) yielded [Ru4(l-H)4(CO)12] (39 mg), 1 (169 mg,
0.237 mmol, 25.5%), 3 (54 mg, 0.064 mmol, 14%), 5
(118 mg, 0.0956 mmol, 30.7%), and 4 (48 mg, 0.048 mmol,
10%), in this order.
A toluene solution (3 mL) of [Ru3(CO)9(l3-PMes)2] (3)
(12 mg, 0.014 mmol) and [Ru3(CO)12] (9 mg, 0.014 mmol)
was stirred under reflux for 2 days. Celite was added to
the reaction mixture, and solvent was removed under
reduced pressure. The celite was then subjected to a silica
gel flash column (2 · 10 cm). Elution with hexane/toluene
(4:1) afforded [Ru3(CO)12] (1 mg) as a first yellow band.
The second brown band and the third red-brown band
yielded unidentified powders (2 mg and 1 mg, respectively)
after evaporation. From the forth violet band, [Ru4-
(CO)10(l-CO)(l4-PMes)2] (4) (11 mg, 0.011 mmol, 78%)
was obtained as violet crystals.
(c) When a toluene (10 mL) solution of [Ru3(CO)12]
(200 mg, 0.313 mmol) and twofold excess PH2Mes
(98 mg, 0.64 mmol) was refluxed overnight and worked
up as above, [Ru4(l-H)4(CO)12] (10 mg),
1 (54 mg,
0.077 mmol, 12%), 3 (13 mg, 0.042 mmol, 13%), 5 (87 mg,
0.070 mmol, 33%), and 4 (23 mg, 0.023 mmol, 7.1%) were
obtained. Under this condition, three kinds of brown oily
products (11, 15, and 15 mg) were obtained after com-
pound 4 was eluted, but they could not be identified.
4.6. Reaction of [Os3(CO)12] with PH2Mes
A toluene solution of [Os3(CO)12] (150 mg, 0.165 mmol)
and PH2Mes (25 mg, 0.16 mmol) was refluxed overnight.
The resulting mixture was filtered and to the filtrate was

Table 1
Crystal data and structure refinements of 1–7
1
2
3
4
5
6
7
Crystal size (mm)
Formula
Fw
0.20 · 0.10 · 0.10
18H13O9PRu3
707.46
0.50 · 0.10 · 0.10
C26H26O8P2Ru3
831.62
0.10 · 0.10 · 0.05
C27H22O9P2Ru3
855.60
0.10 · 0.05 · 0.05
C29H22O11P2Ru4
1012.69
0.20 · 0.15 · 0.10
C37H35O10P3Ru5
1237.91
0.10 · 0.10 · 0.10
C19H13O10Os3P
1002.86
0.30 · 0.20 · 0.10
C18H13O9Os3P
974.85
C
ꢀ
ꢀ
ꢀ
ꢀ
Crystal system
Space group
P1
P1
Pbca
Orthorhombic
8.9384(6)
17.9644(14)
37.794(2)
P212121
Orthorhombic
12.4760(7)
12.4760(7)
21.4411(8)
P1
P21
P1
Triclinic
8.3391(3)
9.2269(6)
16.5936(10)
90.135(2)
102.922(2)
114.998(2)
1121.1(1)
2
Triclinic
8.7796(13)
11.070(2)
16.598(2)
106.435(7)
103.563(6)
94.346(4)
1486.6(4)
2
Triclinic
12.3724(9)
16.8044(8)
23.8596(11)
98.758(2)
102.732(5)
105.908(2)
4532.2(4)
4
Monoclinic
9.3882(10)
8.9896(7)
Triclinic
8.3506(6)
9.1801(6)
16.5294(11)
89.971(3)
76.807(4)
65.370(2)
1115.02(13)
2
˚
a (A)
˚
b (A)
˚
c (A)
14.5184(14)
a (ꢁ)
b (ꢁ)
c (ꢁ)
99.804(5)
3
˚
Volume (A )
6068.6(7)
8
1.873
1.629
3337.3(3)
4
2.016
1.928
1207.4(2)
2
2.758
15.862
Z
qcalc (g cmꢀ3
)
2.096
2.112
680
1.858
1.657
816
1.814
1.783
2408
2.904
17.169
872
l (mmꢀ1
F(000)
)
3344
1960
900
Reflections collected
Independent
10721
5077
13260
6645
44160
6832
28534
7593
38228
19594
10173
5179
10058
4849
reflections
Max. and min.
transmission
[R(int) = 0.0188]
0.8166 and 0.6774
[R(int) = 0.0359]
0.8518 and 0.4913
[R(int) = 0.0989]
0.9230 and 0.8541
[R(int) = 0.0628]
0.9098 and 0.8306
[R(int) = 0.0461]
0.8418 and 0.7169
[R(int) = 0.0440]
0.2999 and 0.2999
[R(int) = 0.0442]
0.2786 and 0.0791
Data/restrains/
parameters
GOF on F2
5077/0/291
6645/0/374
6832/0/376
7593/0/421
19594/0/1009
5179/0/309
4849/0/290
1.295
1.164
1.238
1.264
1.095
1.069
1.269
Final R indices
[I > 2r(I)]
R indices (all data)
R1 = 0.0216,
wR2 = 0.0736
R1 = 0.0249,
wR2 = 0.0961
0.785 and ꢀ1.088
R1 = 0.0420,
wR2 = 0.1324
R1 = 0.0496,
wR2 = 0.1789
1.295 and ꢀ3.904
R1 = 0.0743,
wR2 = 0.1392
R1 = 0.0891,
wR2 = 0.1622
1.384 and ꢀ1.632
R1 = 0.0422,
wR2 = 0.1024
R1 = 0.0513,
wR2 = 0.1158
0.919 and ꢀ1.073
R1 = 0.0600,
wR2 = 0.1809
R1 = 0.0731,
wR2 = 0.1998
3.648 and ꢀ2.321
R1 = 0.0397,
wR2 = 0.1116
R1 = 0.0407,
wR2 = 0.1154
1.371 and ꢀ2.843
R1 = 0.0382,
wR2 = 0.1122
R1 = 0.0394,
wR2 = 0.1130
1.643 and ꢀ3.523
Largest diff. peaꢀk3
˚
and hole (e A
)

T. Kakizawa et al. / Journal of Organometallic Chemistry 691 (2006) 726–736
735
added celite. After removal of solvent, the celite was sub-
jected to a silica gel flash column (3 · 20 cm) and chromato-
graphed with a hexane/toluene (10:1) mixture. The first
yellow fraction was evaporated to afford [Os3(CO)10(l-H)-
(l-PHMes)] (6) (31 mg, 0.031 mmol, 19%) and the second
pale yellow fraction gave [Os3(CO)9(l-H)2(l3-PMes)] (7)
(63 mg, 0.065 mmol, 40%).
applied. The crystallographic data are listed in Table 1.
The structures were solved by Patterson and Fourier syn-
thesis methods using SHELXS-97 [12] and refined by full
matrix least-squares techniques on all F2 data. In com-
plexes 1–4, 6, and 7, the hydrogen atoms bridging
Ru–Ru or Os–Os bonds and on the phosphorus atoms
were located by the differential Fourier syntheses and
refined isotropically. In complex 5, hydrogens on Ru atoms
were not located.
6: yellow platelets. 1H NMR (300 MHz, CD2Cl2): d
ꢀ18.61 (dd, 1H, 2JPH = 19.0 Hz, 3JHH = 4.5 Hz, l-H), 2.16
(s, 3H, p-CH3), 2.42 (s, 6H, o-CH3), 6.81 (d, 2H,
1
4JPH = 3.6 Hz, ArH), 7.82 (dd, 1H, JPH = 413.4 Hz,
Acknowledgment
3JHH = 4.5 Hz, l-PH). 31P NMR (121.5 MHz, CD2Cl2): d
ꢀ84.6 (dd, JPH = 413.4 Hz, JPH = 19.0 Hz). 13C NMR
This work was supported by the 21st century Center of
Excellence (COE) program ÔGiant Molecules and Complex
SystemsÕ of MEXT hosted at Tohoku University.
(75.5 MHz, CD2Cl2):
d 21.0 (s, p-CH3), 24.5 (d,
JPC = 11.3 Hz, o-CH3), 125.7 (d, JPC = 47.5 Hz, ipso-
C6H2Me3), 131.1 (d, JPC = 9.06 Hz, m-C6H2Me3), 140.4 (s,
o-C6H2Me3), 141.6 (d, JPC = 9.1 Hz, p-C6H2Me3), 170.8
(d, JPC = 9.1 Hz), 173.7 (s), 173.6. (d, JPC = 9.1 Hz), 177.7
(s), 178.5 (s), 180.9 (d, JPC = 10.3 Hz), 185.0 (d,
JPC = 20.7 Hz) (all for CO). IR mCO (KBr, cmꢀ1): 2101 (s),
2056 (vs), 2047 (vs), 2032 (m), 2015 (m) 1997 (s), 1985 (s),
1970 (s). Anal. Calc. for C18H13O9Os3P: C, 22.75; H, 1.31,
Found: C, 22.83; H, 1.32.
Appendix A. Supplementary data
Crystallographic Information has been deposited with
the Cambridge Crystallographic Data Centre (CCDC
Nos. 273654 (1), 273655 (2), 273656 (3), 273657 (4),
273658 (5), 273659 (6), and 273660 (7)). The data can be
obtained free of charge via www.ccdc.cam.ac.uk (or from
the Cambridge Crystallographic Data Centre, 12 Union
Road, Cambridge CB21EZ, UK; fax: (+44) 1223 336
033; or deposit@ccdc.cam.ac.uk). Supplementary data
associated with this article can be found, in the online ver-
sion, at doi:10.1016/j.jorganchem.2005.10.011.
1
7: pale yellow prisms. H NMR (300 MHz, CD2Cl2): d
2
ꢀ20.84 (d, 2H, JPH = 9.9 Hz, l-H), 2.23 (s, 3H, p-CH3),
4
2.65 (s, 6H, o-CH3), 6.97 (d, 2H, JPH = 4.5 Hz, ArH).
31P NMR (121.5 MHz, CD2Cl2): d 53.6 (br, m). 13C
NMR (75.5 MHz, CD2Cl2): d 21.2 (s, p-CH3), 27.0 (d,
JPC = 12.8 Hz, o-CH3), 119.8 (d, JPC = 18.1 Hz, ipso-
C6H2Me3), 130.6 (d, JPC = 9.1 Hz, m-C6H2Me3), 141.3
(d, JPC = 3.8 Hz, p-C6H2Me3), 142.9 (d, JPC = 9.8 Hz,
o-C6H2Me3), 155.5 (br), 162.1 (br), 169.4 (br), 171.9 (br),
176.6 (br) (all for CO). IR mCO (KBr, cmꢀ1): 2104 (s),
2071 (s), 2039 (vs), 2018 (s), 1996 (s), 1983 (s), 1968 (s).
Anal. Calc. for C18H13O9Os3P: C, 22.17; H, 1.34, Found:
C, 22.22; H, 1.33.
References
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was removed under vacuum. Recrystallization from hexane
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Single crystals of 1, 2, 3, 4, and 5 suitable for X-ray dif-
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solutions layered with hexane at ꢀ30 ꢁC. Crystals of 6
and 7 were grown from the CH2Cl2 solutions layered with
hexane at room temperature. Intensity data were collected
on a RIGAKU RAXIS-RAPID Imaging Plate diffractom-
eter with graphite monochromated Mo Ka radiation at
150 K. The data were corrected for Lorentz and polariza-
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