Use of the cationic fragments [Ru(η5-C5H 5)(MeCN)3]+ and [M(η6-C 6H5R)(MeCN)3]+ (M=Os, Ru; R=H, Me) as ionic coupling reagents with the anions

Article abstract of DOI:10.1016/S0020-1693(02)01516-5

The cluster [H₂Os₄(CO)₁₃] may be reduced with K/Ph₂CO to generate an anion which reacts with [M(η ⁶-C₆H₅R)(MeCN)₃]²⁺ (M=Os, Ru; R=H, Me) affording the capped clusters [H₂Os₄M(CO) ₁₂(η⁶-C₆H₅R)] (M=Os, R=H (1); M=Ru, R=H (2); M=Os, R=Me (3)) with the arene ligand on one of the axial site of a trigonal bipyramid. The Os clusters 1 and 3 transform into the more stable equatorial isomers, 4 and 5, respectively, in 24 h. The structure of 5 has been confirmed by a single crystal X-ray diffraction study, and all the complexes have been characterised spectroscopically. The axial isomers may be carbonylated or hydrogenated to generate the edge-bridged tetrahedral clusters [H₂Os₄M(CO)₁₃(η⁶-C ₆H₅R)] (M=Os, R=H (6); M=Ru, R=H (7); M=Os, R=Me (8)) and the known clusters [H₄Os₄M(CO)₁₂(η ⁶-C₆H₆)] (M=Os (9); Ru (10)). The structure of 7 has been confirmed by an X-ray diffraction analysis. The axial isomer 1 reacts with PPh₂Me to yield the addition product [H ₂Os₅(CO)₁₂(η⁶-C ₆H₆)PPh₂Me] (11), whereas the mixed osmium-ruthenium analogue undergoes a transformation to the 'spiked' tetrahedral [H₃Os₄Ru(CO)₁₂(μ ₃-σ,σ,η⁶-C₆H ₅)PPh₂Me] (12). Deprotonation of the axial isomers 1 and 2 and subsequent reaction with [AuPPh₃]⁺ yields [HOs ₄M(CO)₁₂(C₆H₆)(AuPPh₃)] (M=Os (13); Ru (14)). As well as spectroscopic characterisation cluster, the structures of 11, 12 and 13 have been established by X-ray diffraction experiments. In a related series of reactions the cluster monoanion [Os ₄(CO)₁₃X]^- (X=Cl (15), Br (16), I (17)) may be capped using the monocation [Ru(η⁵-C₅H ₅)(MeCN)₃]⁺ affording [HOs₄Ru(CO) ₁₃(η⁵-C₅H₅)] (18), which is readily deprotonated and further capped with [AuPPh₃]⁺ to afford the neutral cluster [Os₄(CO)₁₃Ru(η ⁵-C₅H₅)AuPPh₃] (20). The structures of 15, 18 and 20 have been established crystallographically. The cluster anion [Os₄(CO)₁₃X]^- may be reduced with K/Ph ₂CO and the resulting anionic complex coupled with [Ru(η ⁵-C₅H₅)(MeCN)₃]⁺, providing another route to [Os₄Ru(CO)₁₃(η ⁵-C₅H₅)]^- (19). This anionic complex may also be coupled with [Ru(η⁶-C₆H ₆)(MeCN)₃]²⁺ affording [Os₄Ru(CO) ₁₃(η⁶-C₆H₆)] (21) which has also been structurally characterised.

Full text of DOI:10.1016/S0020-1693(02)01516-5

Inorganica Chimica Acta 350 (2003) 299Á313
/
www.elsevier.com/locate/ica
Use of the cationic fragments [Ru(h5-C5H5)(MeCN)3]ꢀ and
[M(h6-C6H5R)(MeCN)3]ꢀ (Mꢁ
Os, Ru; RꢁH, Me) as ionic
coupling reagents with the anions [H2Os4(CO)12]2ꢂ,
[Os4(CO)13X]ꢂ (XꢁCl, Br, I) and [Os4(CO)13]2ꢂ
/
/
/
in the synthesis of arene and cyclopentadienyl clusters
Muna R.A. Al-Mandhary a, Radchada Buntem a, Christopher Cathey a, Jack Lewis a,
M. Carmen Ramirez de Arellano a, Gregory P. Shields a, Cheryl L. Doherty b,
Paul R. Raithby b,*
a Department of Chemistry, Lensfield Road, Cambridge CB2 1EW, UK
b Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK
Received 28 June 2002; accepted 23 September 2002
This paper is dedicated to Professor Pierre Braunstein in recognition of his outstanding contribution to organometallic and cluster chemistry.
Abstract
The cluster [H2Os4(CO)13] may be reduced with K/Ph2CO to generate an anion which reacts with [M(h6-C6H5R)(MeCN)3]2ꢀ
(Mꢁ
Os, Rꢁ
/
Os, Ru; Rꢁ
/
H, Me) affording the capped clusters [H2Os4M(CO)12(h6-C6H5R)] (Mꢁ
Me (3)) with the arene ligand on one of the axial site of a trigonal bipyramid. The Os clusters 1 and 3 transform into the
/
Os, Rꢁ
/
H (1); Mꢁ
/
Ru, Rꢁ
/
H (2); Mꢁ
/
/
more stable equatorial isomers, 4 and 5, respectively, in 24 h. The structure of 5 has been confirmed by a single crystal X-ray
diffraction study, and all the complexes have been characterised spectroscopically. The axial isomers may be carbonylated or
hydrogenated to generate the edge-bridged tetrahedral clusters [H2Os4M(CO)13(h6-C6H5R)] (Mꢁ
/
Os, Rꢁ
Os (9); Ru (10)). The structure of 7 has been
confirmed by an X-ray diffraction analysis. The axial isomer 1 reacts with PPh2Me to yield the addition product [H2Os5(CO)12(h6-
C6H6)PPh2Me] (11), whereas the mixed osmiumÁruthenium analogue undergoes a transformation to the ‘spiked’ tetrahedral
[H3Os4Ru(CO)12(m3-s,s,h6-C6H5)PPh2Me] (12). Deprotonation of the axial isomers 1 and 2 and subsequent reaction with
[AuPPh3]ꢀ yields [HOs4M(CO)12(C6H6)(AuPPh3)] (Mꢁ
Os (13); Ru (14)). As well as spectroscopic characterisation cluster, the
structures of 11, 12 and 13 have been established by X-ray diffraction experiments. In a related series of reactions the cluster
/
H (6); Mꢁ
/
Ru, RꢁH
/
(7); Mꢁ
/
Os, Rꢁ
/
Me (8)) and the known clusters [H4Os4M(CO)12(h6-C6H6)] (Mꢁ
/
/
/
monoanion [Os4(CO)13X]ꢂ (XꢁCl (15), Br (16), I (17)) may be capped using the monocation [Ru(h5-C5H5)(MeCN)3]ꢀ affording
/
[HOs4Ru(CO)13(h5-C5H5)] (18), which is readily deprotonated and further capped with [AuPPh3]ꢀ to afford the neutral cluster
[Os4(CO)13Ru(h5-C5H5)AuPPh3] (20). The structures of 15, 18 and 20 have been established crystallographically. The cluster anion
[Os4(CO)13X]ꢂ may be reduced with K/Ph2CO and the resulting anionic complex coupled with [Ru(h5-C5H5)(MeCN)3]ꢀ, providing
another route to [Os4Ru(CO)13(h5-C5H5)]ꢂ (19). This anionic complex may also be coupled with [Ru(h6-C6H6)(MeCN)3]2ꢀ
affording [Os4Ru(CO)13(h6-C6H6)] (21) which has also been structurally characterised.
# 2003 Elsevier Science B.V. All rights reserved.
Keywords: Cluster; Carbonyl; Osmium; Ruthenium; Gold; Arene; Cyclopentadiene; Crystal structures
1. Introduction
Use of mono- and dicationic capping reagents in
cluster build-up reactions is now a well-established
synthetic technique for the production of both homo-
* Corresponding author. Tel.: ꢀ
826 231.
E-mail address: p.r.raithby@bath.ac.uk (P.R. Raithby).
/
44-1225-323 183; fax: ꢀ44-1225-
/
0020-1693/03/$ - see front matter # 2003 Elsevier Science B.V. All rights reserved.
doi:10.1016/S0020-1693(02)01516-5

300
M.R.A. Al-Mandhary et al. / Inorganica Chimica Acta 350 (2003) 299Á313
/
metallic and mixed-metal species [1]. In Ru and Os
cluster chemistry, initial investigations focused on the
room temperature; the arene-H resonance is consistent
with the h6 bonding mode in each case.
On standing for 24 h in dichloromethane solution, 1
and 3 each undergo a colour change, and in each case
two new products 4 and 6 and 5 and 8, respectively, were
isolated from the resulting mixture in approximately
dicationic species ‘M(C6H5R)2ꢀ’ (Mꢁ
/
Os, Ru; Rꢁ
Me) with the anions [Os3(CO)9(R1C2R2)]2ꢂ (R1ꢁR2ꢁ
H, Et, Ph) [2],
/
H,
/
/
Me, Et, Ph; R1ꢁ
/
Me, R2ꢁ
/
[Os4H4(CO)11]2ꢂ [3,4], [Os5(CO)15]2ꢂ, [Os6(CO)17]2ꢂ
and [Os7(CO)20]2ꢂ [5].
equal (ꢀ40%) yield. Products 4 and 5 have very similar
/
Monocationic species, when allowed to react with
dianions, offer the possibility of increasing cluster
nuclearity by two metal atoms in one step, with the
additional advantage of lower redox activity. Both
mono- and bicapped species have been produced
IR spectra and the spectroscopic and mass spectrometric
data (Table 1) suggests that 4 and 5 are isomers of 1 and
3 with the same trigonal bipyramidal metal framework
but with the arene ligand coordinated in a different
position. Electronic considerations indicate that the
greater donor character of the metal-arene M(h6-arene),
or a M(h5-C5H5) fragment, compared with a metal-
tricarbonyl unit, enhances electron density donation
from the formally 20eꢂ (equatorial) to the 17eꢂ (axial)
sites, stabilising the trigonal bipyramidal cluster, and
hence, where steric constraints permit, the M(h6-C6H6)
group should occupy the ‘electron-rich’ centre in the
more stable isomer [12]. Unlike 1, 2 and 3, 4 and 5 are
both thermodynamically stable and 5 was crystallised by
slow diffusion from benzene solution and the solid state
structure determined by single-crystal X-ray diffraction
(Table 2). Consistent with the spectroscopic evidence,
the cluster 5 does has a trigonal bipyramidal Os5 core
with the toluene ligand coordinated to the equatorial
Os(5) as shown in Fig. 1. The hydride ligands where not
located, but potential energy calculations [14] suggest
successfully
C5H5)(MeCN)3]ꢀ with a wide range of dianions,
including [6],
[Os5(CO)15]2ꢂ [Ru5C(CO)14]2ꢂ
[Ru6C(CO)16]2ꢂ [7], [Os3(CO)11]2ꢂ [8], and more re-
cently mixed OsÃCo [9], OsÃAu [10], and phosphine-
substituted species [11].
via
the
reaction
of
[Ru(h5-
,
/
/
The structures of many of the penta-, hexa- and
heptanuclear species have been summarised in a recent
review [12]. We have previously published a preliminary
report on the product of the reaction of
‘[H2Os4(CO)12]2ꢂ’ with ‘Ru(C6H6)2ꢀ’ followed by the
addition of P(OMe)3 to form a spiked tetrahedral cluster
with an orthometallated arene ring [13]. In this paper,
we describe further the reactions of ‘[H2Os4(CO)12]2ꢂ
and extend them to the related tetranuclear anions
[Os4(CO)13X]ꢂ (XꢁCl, Br, I) and ‘[Os4(CO)13]2ꢂ’,
’
/
and compare the reactivity of the capped products
formed.
that they bridge the Os(2)Ã
edges. The structure is similar to those of the tetrahy-
Os, Ru)
prepared by reducing [Os4H4(CO)12] with potassium
diphenylketyl and reacting the resulting anion with
/
Os(3) and Os(2)Ã
/
Os(4)
drido clusters [H4Os4M(CO)11(h6-C6H6)] (Mꢁ
/
2. Results and discussion
[M(h6-C6H6)(MeCN)3] (Mꢁ
/
Ru, Os) [4]. The
[H4Os4M(CO)11(h6-C6H6)] clusters, which are the initial
products of the reaction have arene ligand in the
equatorial site and are thermodynamically stable.
2.1. Reaction of [H2Os4(CO)12]2ꢂ with [M(h6-
C6H5R)]2ꢀ (Rꢁ
H, Me)
/
The neutral cluster [H2Os4(CO)13] was reduced with
potassium benzophenone ketyl in THF and the resulting
dianion reacted readily with the cationic reagents [M(h6-
2.2. Reaction of 1Á3 with carbon monoxide
/
In addition to 4 and 5, 1 and 3 also yield carbonyl-
scavenging products [H2Os5(CO)13(C6H5R)] (RꢁH (6),
RꢁMe (8)) (Scheme 1). On standing, 2 does not yield
C6H6)(MeCN)3][BF4]2 (Mꢁ
/
Os, Ru) and [Os(h6-
/
C6H5Me)(CF3SO3)2] to produce
the
clusters
/
[H2Os5(CO)12(C6H6)] (1), [H2Os4Ru(CO)12(C6H6)] (2)
and [H2Os5(CO)12(C6H5Me)] (3) (Scheme 1). The elec-
tron count of 72 electrons is consistent with these
complexes having a trigonal bipyramidal metal frame-
work. These products were unstable both in solution
and in the solid state, and must be purified, charac-
terised or reacted further within minutes of preparation.
However, it was possible to obtain IR, H NMR and
mass spectra for these species (Table 1). The IR spectra
for the three complexes are very similar which suggests
any isomerisation product, but also produces the
carbonylated product [H2Os4Ru(CO)13(C6H6)] (7) in
approximately 15% yield along with decomposition
products. Clusters 6Á
by bubbling CO through dichloromethane solutions of
1Á3, respectively, for 30 min. For 1 and 2, the addition is
/
8 may also be synthesised directly
/
quantitative, but for 3 approximately 30% of the
isomerisation product 5 is also obtained. The addition
of CO to 1 and 2 is irreversible, no change being
observed when 6 and 7 are heated under reflux in
toluene for 1 h.
1
that 1Á
broad resonance at d ꢂ
but no such hydride peak was observed for 1 or 3 at
/
3 are structurally analogous. Cluster 2 shows a
/
13.75 in the 1H NMR spectrum
The IR spectra of 6Á
/
8 are very similar, suggesting that
the structures are analogous, and the 1H NMR and

M.R.A. Al-Mandhary et al. / Inorganica Chimica Acta 350 (2003) 299Á
/
313
301
Scheme 1.
mass spectra are consistent with the proposed formulae.
The addition of CO to a trigonal bipyramidal Os4Ru
core results in an increase in the electron count of two
electrons, and 74 electron systems usually exhibit a
square-based pyramidal or edge-bridged tetrahedral
core. The latter would be expected by analogy with the
related dihydrido clusters [H2Os5(CO)16] [15] and
2.4. Reaction of 1 and 2 with PPh2Me
Clusters 1 and 2 react rapidly with PPh2Me in
dichloromethane at room temperature to yield a dull
greenÁ/brown
product
[H2Os5(CO)12(PPh2Me)(h6-
C6H6)] (11) and bright orange compound [H3Os4-
Ru(CO)12(m3-s,s,h6-C6H5)PPh2Me] (12), respectively
(Scheme 1). These products are not structurally analo-
gous, unlike those from the addition reactions with CO
[H2Os4Rh(CO)13(h5-C5R5)] (Rꢁ
/H, Me) [16,17].
[H2Os4Ru(CO)13(h6-C6H6)] (7) was crystallised by
slow diffusion of hexane into a saturated dichloro-
methane solution and a single-crystal X-ray analysis
confirmed the edge-bridge tetrahedral molecular struc-
ture. The molecular structure is shown in Fig. 2 and
selected bond parameters are listed in Table 3. The
hydride ligands were not located, but potential energy
calculations [14] suggest that they bridge the two longest
1
and H2, as demonstrated by their IR, H and 31P NMR
spectra (Table 1). Cluster 11 shows a singlet h6-benzene
resonance and two hydride resonances, one of which
exhibits coupling with the 31P of the phosphine (JPH
ꢁ
/
14.4 Hz). These data are consistent with a simple
addition reaction of phosphine, which is confirmed by
a diffraction study of a single crystal grown by slow
evaporation from benzene. The molecular structure of
11 is shown in Fig. 3 and selected bond parameters are
presented in Table 4. The cluster has an edge-bridged
tetrahedral geometry, the phosphine addition having
occurred at an equatorial site with the ‘Os(CO)(h6-
C6H6)’ unit adopting the edge-bridging position. The
hydride ligands were not located, but potential energy
edges, Os(1)Ã
[H2Os4Rh(CO)13(h5-C5R5)] [12] analogues, while the
shortest Os(1)ÃOs(2) edge is bridged by the Ru(1)
atom. The bond parameters for 7 are also very similar
H, Me)
/
Os(3) and Os(2)Ã
/
Os(3) as in the
/
to those in [H2Os4Rh(CO)13(h5-C5R5)] (Rꢁ
/
[12].
calculations indicate that they bridge the Os(2)Ã
and Os(3)ÃOs(5) edges, as in [H2Os5(CO)16], consistent
/
Os(5)
2.3. Reaction of 1 and 2 with dihydrogen
/
with the observed JPH coupling. The structure is closely
related to that of 7, PPh2Me replacing one of the CO
ligands. This causes a distortion of the ligand polyhe-
dron, and combined with electronic effects results in an
On bubbling H2 through dichloromethane solutions
of 1 and 2 a gradual colour change from purple and
maroon, respectively, to green occurs over a period of 2
h (Scheme 1). The resulting clusters 9 and 10 were
produced in near quantitative yield. The IR spectra of 9
corresponds to that for the previously reported com-
pound [H4Os5(CO)12(h6-C6H6)] (9) [4] and that of 10 is
very similar, suggesting the corresponding formulation
[H4Os4Ru(CO)12(h6-C6H6)] (10).
incipient CO bridge between C(12) and the edge-
˚
bridging Os(1) centre [Os(1)Ã
/
C(12) 2.57(5) A, Os(2)Ã
/
C(12)Ã
/
O(12) 162(4)8]; the cis edge Os(3)Ã
/
Os(1) is
˚
considerably longer [2.878(2) A] than the edge with the
˚
incipient bridge [2.801(2) A].

Table 1
Spectroscopic data for the new complexes
a
d
IR, n(CO) (cmꢂ1
)
Mass (m/z) exptl. 1H NMR d; J (Hz) d
(calc.)
13C NMR d
31P NMR
1
2
3
4
5
6
7
8
2082(m), 2038(vs), 2028(s), 1995(w),
1981(w)
2081(m), 2038(vs), 2028(s), 1997(w),
1981(w)
2081(m), 2036(vs), 2026(s), 1993(w),
1977(w)
2079(w), 2055(vs), 2037(w), 2019(m),
2001(vs), 1969(w), 1921(w), 1785(wbr)
2078(w), 2055(vs), 2035(w), 2018(m),
2000(vs), 1967(m), 1920(w), 1794(wbr)
2083(m), 2048(s), 2029(vs), 1995(m),
1985(m), 1956(w)
1367(1366) f
1280 (1277) f
6.16 (s, 6H, C6H6)
5.99 (s, 6H, C6H6), ꢂ
/
13.75 (s br, 2H, OsÃ
/
H ÃOs)
/
6.25Á/5.92 (m, 5H, C6H5Me), 2.40 (s, 3H, CH3)
1367 (1366) f
1382 (1380) f
1396 (1394) f
1308 (1305) f
1408 (1408) f
6.16 (s br, 6H, C6H6)
6.58Á
2H, OsÃ
6.04 (s, 6H, C6H6), ꢂ
/
5.94 (m, 5H, C6H5Me), 2.51 (s, 3H, CH3), ꢂ
/
12.35 (s br, 2H, OsÃ
/
H Ã
/
Os), ꢂ20.96 (s,
/
/
H Ã
/
Os)
/
19.50 (s, 2H, OsÃ
/
H Ã
/Os)
2083(w), 2049(m), 2028(vs), 1998(m),
1986(m), 1935(w)
6.09 (s, 6H, C6H6), ꢂ18.66 (s, 2H, OsÃ
/
/
H Ã
/Os)
2082(w), 2048(m), 2028(vs), 1996(w),
1984(w), 1939(w)
11 2074(s), 2039(vs), 2018(s), 1996(s), 1975(m), 1569 (1566)
6.30Á/5.69 (m, 5H, C6H5Me), 2.51 (s, 3H, CH3), ꢂ
/
19.52 (s br, 2H, OsÃ
/
H Ã
/
Os)
7.6 (m, 10H, Ph), 5.42 (s, 6H, C6H6), 2.64(d, 3H, Me, JPH 9.8 Hz) ꢂ17.65 (dd, 1H, OsÃ
ꢁ/
/
/
ꢂ
/
167.07
(s, 1P)
106.98
1942(w)
12 2079(m), 2052(s), 2029(vs), 2012(s),
1971(m)
H ÃOs, Jꢁ1.8, JPH 14.4 Hz), ꢂ19.27 (s, 1H, OsÃH ÃOs)
7.5 (m, 10H, Ph), 6.51 (t, CH, Jꢁ5), 5.31 (t, CH, Jꢁ6), 4.86 (m, CH), 4.05 (d, CH, Jꢁ6.9)
3.99 (d, CH, Jꢁ7.5), 2.02 (d, 3H, JPH 9.2), ꢂ8.71 (1H, JPH 19.5), ꢂ20.98 (s, 1H) ꢂ
21.63 (s, 1H).
7.4 (m, 15H, Ph), 5.90 (s, 6H, C6H6), ꢂ
/
/
ꢁ
/
/
/
/
1481 (1479) f
/
/
/
ꢂ
/
/
ꢁ/
/
ꢁ/
/
/
(s, 1P)
13 2057(w), 2029(vs), 2015(s), 1994(m),
1977(m), 1953(m)
14 2057(w), 2030(vs), 2015(s), 1993(m),
1977(m), 1954(m)
15 2069(w), 2034(s), 2012(s), 1971(m),
1805(wbr).
16 2069(w), 2032(s), 2013(s), 1971(m),
1801(wbr).
17 2068(w), 2030(s), 2012(s), 1968(m),
1801(wbr)
18 2087(w), 2057(vs), 2029(ssh), 2019(s),
2002(msh), 1977(wbr), 1928(wbr),
1722(wbr)
19 2050(w), 2016(s), 1991(m), 1978(m),
1942(mvbr), 1722(wbr)
20 2065(w), 2036(vs), 2017(s), 2005(s),
1981(mbr), 1932(mvbr)
1824 (1479) f
1738 (1736) f
1160 e (1160.3)
1205 e (1204.7)
1251 e (1251.7)
1298 b (1300)
/
12.11 (s, 1H, OsÃ
/
H Ã/Os)
7.4 (m, 15H, Ph), 5.80 (s, 6H, C6H6), ꢂ12.11 (s, 1H, OsÃ
/
/
H Ã/Os)
ꢂ
/
17.50 (s, 1H, OsÃ
/
HÃ
/Os) 5.47 (s, 5H, C5H5)
82.75 (s, 5C, C5H5)
85.45 (s, 5C, C5H5)
130.69 (m, 18C, Ph) 1P, AuP)
1297 c (1299)
5.3 (s, 5H, C5H5)
1760 b, 1758 c
(1760)
5.42 (s, 5H, C5H5) 7.51 (m, 15H, Ph)
6.49 (s, 6H, C6H6)
77.02 (s,
21 2075(w), 2045(s), 2020(msh), 2010(m),
1978(wbr), 1924(vwbr)
1314 c (1312)
v, very; s, strong; m, medium; w, weak; sh, sharp; and br, broad.
a
Spectra run in CH2Cl2.
Positive-ion FAB based on 102Ru and 192Os.
b
c
Negative-ion FAB based on 102Ru and 192Os.
Spectra run in CDCl3.
d
e
Negative-ion FAB.
Positive-ion FAB based on 101Ru and 190Os.
f

M.R.A. Al-Mandhary et al. / Inorganica Chimica Acta 350 (2003) 299Á
/
313
303
Table 2
Selected bond lengths (A) and angles (8) for 5
Table 3
Selected bond lengths (A) and angles (8) for 7
˚
˚
Os(1)Ã
Os(1)Ã
Os(2)Ã
Os(2)Ã
Os(4)Ã
Os(5)Ã
/
Os(2)
Os(4)
Os(3)
Os(5)
Os(5)
C(1)
2.792(3) Os(1)Ã
2.803(3) Os(1)Ã
2.767(3) Os(2)Ã
2.815(3) Os(3)Ã
2.810(4) Os(1)Ã
1.87(6) Os(5)Ã
/
Os(3)
Os(5)
Os(4)
Os(5)
C(1)
2.832(3)
2.827(3)
2.778(3)
2.797(3)
2.47(6)
Os(1)Ã
Os(1)Ã
Os(2)Ã
Os(2)Ã
Ru(1)Ã
/
Os(2)
Os(4)
Os(3)
Ru(1)
2.7527(16)
2.8216(17)
2.9592(17)
2.842(3)
Os(1)Ã
Os(1)Ã
Os(2)Ã
Os(3)Ã
/
Os(3)
Ru(1)
Os(4)
Os(4)
2.9622(16)
2.829(3)
/
/
/
/
/
/
/
/
2.8339(17)
2.7791(18)
/
/
/
/
/
/
/C(C6H6)
2.23(4)Á2.28(4)
/
/
/C(C6H5Me) 2.22(6)Á
/
2.38(6)
Os(1)ÃRu(1)Ã
/
/
Os(2) 58.07(5)
Ru(1)Ã
/
Os(1)Ã
/
Os(3) 98.85(6)
Os(1)Ã
/
C(1)Ã
C(1)Ã
/
Os(5)
80(2)
158(5)
Os(1)Ã
/
C(1)ÃO(1) 119(5)
/
Ru(1)ÃOs(2)Ã
/
/
Os(3) 98.63(7)
Os(5)Ã
/
/O(1)
Fig. 3. The molecular structure of [H2Os5(CO)12(h6-C6H6)PPh2Me]
(11); the ellipsoids are shown at the 30% probability level.
Fig. 1. The molecular structure of [H2Os5(CO)12(h6-C6H5Me)] (5); the
ellipsoids are shown at the 30% probability level.
Table 4
˚
Selected bond lengths (A) and angles (8) for 11
Os(1)Ã
Os(2)Ã
Os(2)Ã
Os(3)Ã
Os(1)Ã
Os(2)Ã
/
Os(2)
Os(3)
Os(5)
Os(5)
C(C6H6)
C(8)
2.8035(18)
2.775(2)
2.957(2)
2.972(2)
Os(1)Ã
Os(2)Ã
Os(3)Ã
Os(4)Ã
2.34(4) Os(3)Ã
Os(1)Ã
/
Os(3)
Os(4)
Os(4)
Os(5)
P(1)
2.879(2)
2.791(2)
2.847(2)
2.796(2)
2.394(9)
2.56(4)
/
/
/
/
/
/
/
2.20(3)Á
/
/
/
1.94(4)
/
C(8)
Os(1)Ã
Os(4)Ã
Os(1)Ã
/
Os(3)Ã
Os(3)Ã
C(8)Ã
/
P(1) 88.6(2)
P(1) 151.1(2)
Os(2)Ã
Os(2)Ã
/
Os(3)Ã
C(8)Ã
/
P(1) 144.2(3)
160(3)
/
/
/
/
O(2)
/
/
O(2)
124(3)
ring to the metal core. The 1H NMR and IR spectra are
similar to those for the previously reported cluster
[H3Os4(CO)12Ru{P(OMe)3}(h6-C6H5)] [13] which was
prepared by a similar route. In that case, another
product [H2Os4(CO)12Ru{P(OMe)3}(h6-C6H6)] was
also characterised spectroscopically, and it was sug-
gested that in this compound the phosphine addition
occurred at the Ru atom to generate an edge-bridged
tetrahedral structure which subsequently underwent
orthometallation to form the sterically-favoured ther-
modynamic product [13]. Conversely, in the reaction
Fig. 2. The molecular structure of [H2Os4Ru(CO)13(h6-C6H6)] (7); the
ellipsoids are shown at the 30% probability level.
Conversely, 12 displays three hydride resonances in
the 1H NMR spectrum in a 1:1:1 ratio, a doublet (JPH
ꢁ
/
19.5 Hz) and two singlets. The arene region of the
spectrum is considerably more complex than that of 11,
with five resonances with the same integration, suggest-
ing that a proton has been transferred from the arene

304
M.R.A. Al-Mandhary et al. / Inorganica Chimica Acta 350 (2003) 299Á313
/
Table 5
Selected bond lengths (A) and angles (8) for 12
˚
Os(1)Ã
Os(1)Ã
Os(2)Ã
Os(3)Ã
Ru(1)Ã
Os(1)ÃC(51)
/
Os(2)
Os(4)
Os(3)
Os(4)
2.8111(15)
2.7693(16)
2.9704(15)
2.7893(16)
Os(1)Ã
Os(1)Ã
Os(2)Ã
Ru(1)Ã
2.38(2) Os(3)Ã
Os(2)Ã
/
Os(3)
Ru(1)
Os(4)
2.9600(18))
3.006(2)
2.8330(16)
2.314(8)
2.394(9)
2.56(4)
/
/
/
/
/
/P(1)
/C(C6H5)
2.24(3)Á
/
/
P(1)
/
2.31(2)
/
C(51)
Os(1)ÃRu(1)Ã
/
/
P(1)
105.1(2)
P(1)Ã
/
Ru(1)Ã
/
127.5(7)
89.4(11)
106.5(17)
120.4(18)
C(51)
Os(1)Ã
C(52)Ã
C(56)Ã
C(56)Ã
/
Ru(1)Ã
C(51)Ã
C(51)Ã
C(51)Ã
/
C(61) 106.4(11)
P(1)Ã
/
Ru(1)Ã
/
C(61)
/
/
C(56) 115(2)
C(52)Ã
Os(1)
/
C(51)Ã
/
Fig. 4. Molecular structure of [H3Os4Ru(CO)12(h6-C6H5)PPh2Me]
(12); the ellipsoids are shown at the 30% probability level.
/
/
Os(1) 113.2(16)
C(52)Ã
Os(2)
/
C(51)Ã
/
/
/
Os(2) 117.3(19)
with PPh2Me, only the final product 6 could be
identified.
[H4Os5(CO)12(h6-C6H6)] [4] were also isolated. Clusters
13 and 14 have similar IR spectra and are structurally
analogous. Both display singlets for the h6-C6H6 pro-
tons and the hydride ligands in the 1H NMR spectra; the
chemical shifts of the latter are significantly downfield of
those in the related compound [HOs5(CO)15AuPPh3]
[18]. To confirm the structure of 13, single crystals were
To confirm the molecular structure of 12, and
compare the dimensions with [H3Os4(CO)12Ru{P(O-
Me)3}(m3-s,s,h6-C6H5)], single crystals were grown by
diffusion of hexane into a saturated solution in dichlor-
omethane and a diffraction study undertaken. The
molecular structure is shown in Fig. 4 and selected
bond parameters are listed in Table 5. The hydride
ligands were not located, but potential energy calcula-
tions [14] indicate that they bridge the same edges as in
the P(OMe)3 analogue, with one hydride spanning the
grown by slow evaporation from dichloromethaneÁ
/
hexane solution and an X-ray analysis was undertaken.
The molecular structure of 13 is shown in Fig. 5 and
selected bond lengths and angles are given in Table 6.
The cluster adopts a trigonal bipyramidal core with the
AuPPh3 moiety capping an Os3 face, consistent with an
electron count of 72 electrons, if the gold phosphine unit
is considered as a one electron donor. Potential energy
calculations indicate that the hydride ligand bridges an
‘spike’ Os(1)Ã
the Os(1)ÃOs(3) and Os(2)Ã
structure is very similar to the P(OMe)3 compound,
there being no significant differences in MÃM distances
in the ‘spiked’ tetrahedral metal core. The Os(1)Ã
Ru(1)ÃP(1) angle is larger in the PPh2Me [105.1(2)8]
derivative than in the P(OMe)3 [100.8(6)8] structure,
/Ru(1) edge, and the other two bridging
/
/
Os(3) edges. The overall
/
/
/
equatorial Os(1)Ã
/
Os(3) edge and is coordinated to the
metal that is also bonded to the C6H6 ligand. The arene
ligand thus adopts the electronically favoured equatorial
site, as in 4, and a similar transformation must occur
[13]. The structure is very similar to that of the parent
although there are no significant differences in MÃ
/C
distances involving the {m3-h6-C6H5} ring.
2.5. Deprotonation of 1 and 2 and reaction with
[AuPPh3]ꢀ
Clusters 1 and 2 may be deprotonated with NEt3 in
dichloromethane, at room temperature, to form the
monoanion [HOs4M(CO)12(h6-C6H6)]ꢂ and dianion
[Os4M(CO)12(h6-C6H6)]2ꢂ (Mꢁ
/
Ru, Os). To isolate
the monoanion, the solution was monitored by IR
spectroscopy and the solvent was removed when the
major absorptions had shifted halfway from the values
in the starting material to those in the dianion
[Os4M(CO)12(h6-C6H6)]2ꢂ (Mꢁ
/Ru, Os). After wash-
ing the dry mixtures with hexane to remove the
remaining base, excess [AuPPh3][NO3], in CH2Cl2, was
added and the mixture stirred for 1 h, yielding a mono-
gold
(Mꢁ
1). In the case of 1, small quantities of the known cluster
complexes
[HOs4M(CO)12(h6-C6H6)AuPPh3]
Fig. 5. Molecular structure of [HOs5(CO)12(h6-C6H6)AuPPh3] (13);
the ellipsoids are shown at the 30% probability level.
/
Os (13), Ru (14)) amongst other products (Scheme

M.R.A. Al-Mandhary et al. / Inorganica Chimica Acta 350 (2003) 299Á
/
313
305
Table 6
Selected bond lengths (A) and angles (8) for 13
˚
Os(1)Ã
Os(1)Ã
Os(1)Ã
Os(2)Ã
Os(2)Ã
Os(3)Ã
Os(3)Ã
/
Os(2)
2.8915(15)
2.9043(16)
2.8420(19)
2.7414(18)
2.8188(19)
2.7662(18)
Os(1)Ã
Os(1)Ã
Os(2)Ã
Os(2)Ã
Os(3)Ã
Os(4)Ã
2.26(4) Au(1)Ã
/
Os(3)
Os(5)
Os(3)
Os(5)
Os(4)
Au(1)
2.8535(19))
2.8071(19)
2.7903(19)
2.7785(18)
2.755(2)
/Os(4)
/
/Au(1)
/
/Os(4)
/
/Au(1)
/
/Os(5)
/
3.020(2)
/C(C6H6)
2.23(3)Á
/
/
P(1)
2.285(7)
P(1)Ã
/
Au(1)Ã
/
Os(1) 144.92(17)
Os(4) 143.0(2)
P(1)Ã
/
Au(1)Ã
/
Os(2) 147.86(19)
P(1)Ã
/
Au(1)Ã
/
cluster [HOs5(CO)15AuPPh3] [18], although the bond
lengths do differ in detail: those involving the Os bound
to the arene ligand are significantly shorter (mean 2.792
˚
˚
A) than those in the parent compound (mean 2.838 A),
and the edge lengthening effect of the bridging hydride
ligand is less significant. The AuPPh3 moiety bridges
Fig. 6. The structure of the [Os4(CO)13Cl]ꢂ anion (15); the ellipsoids
are shown at the 30% probability level.
asymmetrically in each cluster, and the longest AuÃ
/
Os
Table 7
bond in 13 is to the axial Os(4) atom, a trend that is also
observed in the parent cluster.
˚
Selected bond lengths (A) and angles (8) for 15
Os(1)Ã
Os(1)Ã
Os(3)Ã
Os(4)Ã
Os(3)Ã
/
Os(2)
Os(4)
Os(4)
Cl
2.823(1)
2.823(1)
2.811(2)
2.481(6)
2.24(2)
Os(1)Ã
Os(2)Ã
Os(2)Ã
Os(1)Ã
/
Os(3)
Os(3)
Cl
2.827(1)
2.826(2)
2.490(4)
2.12(2)
/
/
2.6. Reactivity of 4 towards CO, H2 and PPh2Me
/
/
/
/C(14)
The equatorial isomer of [H2Os5(CO)13(h6-C6H6)] (4)
is considerably less reactive towards electrophiles than
the unstable axial isomer [H2Os5(CO)13(h6-C6H6)] (1).
No reaction occurs when H2 or CO gas is bubbled
through solutions of 4 for 2 h at room temperature.
Similarly, there is no reaction observed when PPh2Me is
stirred with a solution of 4 for 5 h at room temperature.
/
C(14)
Os(2)Ã
Os(2)Ã
Os(3)Ã
/
Os(1)Ã
ClÃOs(4)
C(14)ÃO(14)
/
Os(4)
78.7(1)
92.1(2)
134.9(14)
Os(2)Ã
/
Os(3)Ã
C(14)Ã
/
Os(4)
78.8(1)
144.3(13)
/
/
Os(1)Ã
/
/
O(14)
/
/
clusters [H3Os4(CO)12Cl] [20] and [H3Os4(CO)12I] [21].
The ClÃOs distances are not significantly longer in 15
Os
angle is greater in the latter [94.9 compared with
92.1(2)8] in 15.
However, after
5
days the addition product
[H2Os5(CO)13(h6-C6H6)PPh2Me] (11) was generated in
approximately 30% yield alongside starting material and
minor products in low yield. This suggests that 1 and 4
may be in equilibrium in solution, the small concentra-
tion of 4 present reacting with the phosphine.
/
than those in [H3Os4(CO)12Cl] although the OsÃ
/
ClÃ
/
2.8. Reaction of [Os4(CO)13X]ꢂ (Xꢁ
[Ru(h5-C5H5)(MeCN)3]ꢀ cation
/Cl, Br, I) with
2.7. Preparation of [Os4(CO)13X]ꢂ (Xꢁ
The cluster anion [Os4(CO)13X]ꢂ (Xꢁ
/
Cl, Br, I)
/Cl (15), Br
The reaction of [Os4(CO)13X]ꢂ (Xꢁ
/
Cl, Br, I) with 1
(16), I (17)) was obtained (as the [(Ph3P)2N]ꢀ, [Et4N]ꢀ,
or [tBuN]ꢀ salt) by reaction of [Os3(CO)12] with the
appropriate halide salt, in approximately 50% yield in
each case. A single crystal of [(Ph3P)2N][Os4(CO)13Cl]
(15) was grown by slow diffusion of methanol into a
CH2Cl2 solution of the salt and the structure has been
determined by single-crystal X-ray diffraction. The
structure of the anion is shown in Fig. 6 while selected
bond parameters are listed in Table 7. The cluster is
mol equiv. of [Ru(h5-C5H5)(MeCN)3][PF6] in dichlor-
omethane, at room temperature, yielded a single pro-
duct [HOs4(CO)13Ru(h5-C5H5)] (18) in each case
(Scheme 2). The 1H NMR spectrum indicated the
presence of a bridging hydride ligand and one h5-
C5H5 ligand. The structure of 18 was determined by
single-crystal X-ray diffraction and exhibits a trigonal
bipyramidal cluster core with the ‘RuCp’ unit in one of
the equatorial sites (Fig. 7); selected bond lengths and
angles are given in Table 8 for the two similar but
independent molecules in the asymmetric unit. The
isostructural
with
the
Ru
analogue
[(Ph3P)2N][Ru4(CO)13Cl] [19]. The anion adopts a
butterfly arrangement of the four Os atoms with the
Cl ligand bridging the two wings of the butterfly, as the
halide in [Ru4(CO)13Cl]ꢂ and the neutral butterfly
metalÁ
/
metal distances range from 2.727(2) to 2.987(2)
A, which is comparable to the ranges in related arene
complexes [4] and
[H4Os4(CO)11Ru(h5-C6H6)]
˚

306
M.R.A. Al-Mandhary et al. / Inorganica Chimica Acta 350 (2003) 299Á313
/
Scheme 2.
[H2Os5(CO)12(h5-C6H5Me)] (5) in which the arene
ligands are also coordinated in the electronically-
favoured equatorial site [12,13]. However, in this case
the equatorial isomer is probably the kinetic as well as
the thermodynamic product, as the butterfly anion is
‘capped’ without any cluster rearrangement occurring.
The longest distances involve the Ru atom, which has
the highest connectivity and formal electron count.
Potential energy calculations [14] indicate that the
Table 8
Selected bond lengths (A) and angles (8) for 18
˚
Os(1a)Ã
Os(1a)Ã
Os(1a)Ã
Os(2a)Ã
Os(2a)Ã
Os(2a)Ã
Os(3a)Ã
Os(4a)Ã
/
Os(2a)
Os(3a)
Ru(1a)
Os(3a)
Os(4a)
Ru(1a)
Os(4a)
Ru(1a)
2.7697(14)
2.7918(13)
2.986(2)
Os(1b)Ã
Os(1b)Ã
Os(1b)Ã
Os(2b)Ã
Os(2b)Ã
Os(2b)Ã
Os(3b)Ã
Os(4b)Ã
/
Os(2b)
Os(3b)
Ru(1b)
Os(3b)
Os(4b)
Ru(1b)
Os(4b)
Ru(1b)
2.7759(14)
2.7894(12)
2.982(2)
/
/
/
/
/
2.7541(12)
2.7266(12)
2.824(2)
/
2.7556(12)
2.7413(12)
2.810(2)
/
/
/
/
/
2.737(2)
2.876(2)
/
2.7353(15)
2.880(2)
/
/
Ru(1a)Ã
/C(C5H5) 2.21(3)Á
/2.27(3)
Ru(1b)Ã
/C(C5H5) 2.19(3)Á
/
hydride ligand bridges the longest Os(1a)Ã
edge. One CO ligand is semi-bridging from Ru(1a) to
Os(3a) [Ru(1a)ÃC(13a)ÃO(13a) 164.2(16)8, Os(3a)Ã
O(13a) 117.8(15)8] whilst the others are
/Ru(1a)
2.28(3)
2.66(2)
1.90(2)
Os(3a)Ã
/
C(13a)
2.60(2)
1.85(3)
Os(3b)Ã
/
C(13b)
/
/
/
Ru(1a)Ã
/C(13a)
Ru(1b)ÃC(13b)
/
C(13a)Ã
/
Os(3a)ÃC(13a)Ã
/
/
119(2)
163(2)
Os(3b)ÃC(13b)Ã
/
/
119(2)
164(2)
pseudo-linearly coordinated.
O(13a)
O(13b)
Ru(1a)Ã
/
C(13a)Ã
/
Ru(1b)Ã
/
C(13b)Ã
/
O(13a)
O(13b)
2.9. Reactivity of [HOs4(CO)13Ru(h5-C5H5)] (18)
towards phosphines
reflux, cluster degradation occurred and the only
products were obtained in very low yield.
Unlike [H2Os5(CO)12(h6-C6H6)] (4), which undergoes
a nucleophilic addition reaction with phosphines to
2.10. Deprotonation of [HOs4(CO)13Ru(h5-C5H5)]
(18) and reaction with [AuPPh3]ꢀ
form
[H2Os5(CO)12(h5-C6H5Me)L] (Lꢁ
5 days, reaction of 18 with Lꢁ
the
edge-bridged
tetrahedral
PPh2Me) (11) after
PPh3, P(OMe)3,
cluster
/
Cluster 18 may be deprotonated with DBU, in
dichloromethane, to generate the monoanionic cluster
[Os4(CO)13Ru(h5-C5H5)]ꢂ (19), that has been charac-
/
PPh2Me, in CH2Cl2, at room temperature, for 5 days
led to the recovery of the starting material. When the
reaction was carried out in dichloromethane, under
terised by IR, 1H NMR spectroscopy and (ꢂ
) FAB
/
mass spectrometry (Table 1). The weak absorption at
1722 cmꢂ1 indicates that a (semi)-bridging carbonyl is
present as in 18. When treated with 1.5 mol equiv. of
[AuPPh3][NO3], the neutral cluster [Os4(CO)13Ru(h5-
C5H5)AuPPh3] (20) is produced in good yield, as
1
characterised by H NMR and IR spectroscopy (Table
1). The structure was determined by X-ray crystal-
lography and showed a trigonal bipyramidal metal
core similar to that in 18, with the ‘AuPPh3’ unit
capping one of the Os3 triangular faces (Fig. 8). Selected
bond parameters are listed in Table 9. No rearrange-
ment of the Os4Ru core occurs and the Ru(h5-C5H5)
group remains at the equatorial site. The metal core
geometry is thus similar to that observed in the related
face-capped
trigonal
bipyramidal
clusters
[HOs5(CO)15AuPPh3] [18] and [HOs5(CO)12(h6-
C6H6)AuPPh3] (13), except that a semi-bridging CO
˚
˚
C(23) 1.81(2) A)
ligand (Os(2)Ã
/
C(23) 2.56(2) A, Ru(1)Ã
/
Fig. 7. The structure of one of the two independent but structurally
similar molecules of [HOs4(CO)13Ru(h5-C5H5)] (18); the ellipsoids are
shown at the 30% probability level.
replaces the m2-H ligand in 20. The AuPPh3 group in 20
˚
Au 2.788(3)Á2.936(2) A] also bridges asymmetri-
[OsÃ
/
/

M.R.A. Al-Mandhary et al. / Inorganica Chimica Acta 350 (2003) 299Á
/
313
307
2.12. Reaction of [Os4(CO)13]2ꢂ with
[Ru(C5H5)(MeCN)3]ꢀ and [Ru(h6-
C6H6)(MeCN)3]2ꢀ
The reaction of [Ru(h5-C5H5)(MeCN)3][PF6] with
[Os4(CO)13]2ꢂ yields the monoanion [Os4(CO)13Ru(h5-
C5H5)]ꢂ (19), described above, directly, as identified by
its IR and 1H NMR spectra (Scheme 2). Similarly, ionic
coupling with the dicationic species [Ru(h6-
C6H6)(MeCN)3][BF4]2 with [Os4(CO)13]2ꢂ yields the
neutral cluster [Os4(CO)13Ru(h6-C6H6)] (21). The struc-
ture of 21 has been determined by single crystal X-ray
diffraction showing the trigonal pyramidal Os4Ru metal
core with the Ru(h6-C6H6) unit (mean RuÃ
2.29 A) in the electronically-favoured equatorial site as
in 18 and 20. The ligand polyhedron is also very similar,
although the semi-bridging CO ligand is more sym-
/C distance
˚
Fig. 8. Molecular structure of [Os4(CO)13Ru(h5-C5H5)AuPPh3] (20);
the ellipsoids are shown at the 30% probability level.
metric [RuÃ
/
C(22)Ã
/
O(22) 143(2)8, Os(2)Ã
/
C(22)Ã
/
O(22)
Table 9
132(2)8]; this semi-bridging ligand allows the redistribu-
tion of the electron density arising from the arene
˚
Selected bond lengths (A) and angles (8) for 20
fragment. As in 18, the RuÃ
/
Os bonds are longer than
Os(1)Ã
Os(1)Ã
Os(2)Ã
Os(2)Ã
Os(4)Ã
Os(2)Ã
/
Os(2)
Os(4)
Os(3)
Ru(1)
Ru(1)
Au(1)
2.827(3)
2.797(2)
2.872(3)
2.850(3)
2.764(2)
2.936(2)
Os(1)Ã
Os(1)Ã
Os(2)Ã
Os(3)Ã
Os(1)Ã
Os(3)Ã
2.294(12) Au(1)Ã
Ru(1)Ã
/
Os(3)
Ru(1)
Os(4)
Ru(1)
Au(1)
Au(1)
2.799(2)
2.814(4)
2.764(3)
2.746(2)
2.788(3)
2.799(2)
2.282(3)
/
/
the OsÃOs bonds, and the shortest bonds are between
/
the formally 17eꢂ Os(3), Os(4) and ‘electron precise’
equatorial Os(1), Os(2) vertices. A point of interest is
that only the thermodynamically favoured product with
the arene in the equatorial position is observed. The
axial isomer which might be expected to result from the
initial ‘capping’ of an Os3 face of [Os4(CO)13]2ꢂ is not
observed, unlike the reaction of ‘Os(C6H6)2ꢀ’ with
[H2Os4(CO)12]2ꢂ where the axial product 1 is observed
initially but transforms to the more stable equatorial
isomer 4, possibly via a Berry pseudo-rotation mechan-
ism [12,13].
/
/
/
/
/
/
/
/
Ru(1)Ã
/
C(C5H5) 2.250(13)Á
/
/P(1)
Os(2)Ã
Os(2)Ã
O(23)
/
C(23)
2.562(13)
/C(23) 1.814(12)
/
C(23)Ã
/
116.6(10)
Ru(1)Ã
/
C(23)Ã 164.1(12)
/
O(23)
cally, suggesting that the AuÃ
‘soft’. The capping Au atom has the effect of increasing
axialÁequatorial distances relative to those in 18,
/Os bonding is relatively
/
whereas the absence of the bridging hydride decreases
the coordination number and formal electron count of
the equatorial Ru atom such that it forms much shorter
bonds than those in 18 that are comparable in length to
2.13. Reactivity of [Os4(CO)13Ru(h6-C6H6)] (21) with
phosphines
the unbridged OsÃ
/
Os axialÁequatorial distances.
/
The cluster [Os4(CO)13Ru(h6-C6H6)] (21), as 18, is not
susceptible to nucleophilic substitution and no reaction
was observed with the phosphines PPh3, P(OMe)3,
PPh2Me at room temperature, and only trace products
in very low yield were observed after heating a CH2Cl2
solution under reflux for 12 h (Table 10, Fig. 9).
2.11. Reduction of [Os4(CO)13X]ꢂ (Xꢁ
(16), I (17))
/
Cl (15), Br
Reduction of the butterfly clusters [Os4(CO)13X]ꢂ
(XꢁCl, Br, I) with potassium diphenylketyl in THF, at
/
room temperature, generates the same reduced species
with IR absorptions at 1987(s), 1964(m) and 1924(w)
cmꢂ1, indicating that there is a higher anionic charge on
the common reduced cluster [22]. A tentative formula-
tion is [Os4(CO)13]2ꢂ, i.e., loss of halide and a two-
electron reduction has occurred. The dianion
[Os4(CO)13]2ꢂ has not been structurally characterised,
but on the basis of electron-counting rules would be
expected to have a tetrahedral core as in the related
60eꢂ monoanion [HOs4(CO)13]ꢂ (structurally charac-
terised as its [(Ph3P)2N]ꢀ salt) [23].
Table 10
˚
Selected bond lengths (A) and angles (8) for 21
Os(1)Ã
Os(1)Ã
Os(2)Ã
Os(2)Ã
Os(4)Ã
Os(2)Ã
/
Os(2)
Os(4)
Os(3)
Ru(1)
Ru(1)
C(22)
2.775(2) Os(1)Ã
2.727(2) Os(1)Ã
2.822(2) Os(2)Ã
2.799(2) Os(3)Ã
2.780(2) Ru(1)Ã
2.19(2) Ru(1)Ã
/
Os(3)
Ru(1)
Os(4)
Ru(1)
2.704(2)
2.787(2)
2.782(2)
2.792(2)
/
/
/
/
/
/
/
/C(C6H6)
2.25(3)Á2.32(2)
1.92(2)
/
/
/C(22)
Os(2)Ã
/
C(22)Ã
/
O(22) 131(2) Ru(1)Ã
/
C(22)ÃO(22) 143(2)
/

308
M.R.A. Al-Mandhary et al. / Inorganica Chimica Acta 350 (2003) 299Á313
/
K2[H2Os4(CO)12] as an orange oil which was used
without further purification.
3.1.2. [H2Os5(CO)12(h6-C6H6)] (1)
CH2Cl2 (20 ml) was added to a sealed flask containing
freshly prepared K2[H2Os4(CO)12] (50 mg, 0.042 mmol)
and an excess of [Os(h6-C6H6)(MeCN)3][BF4]2 (33 mg,
0.068 mmol). The mixture was stirred for 20 min to give
a dark red solution which was concentrated and then
chromatographed by TLC using CH2Cl2:hexane (3:2) as
eluent to give a maroon compound [H2Os5(CO)12(h6-
C6H6)] (1) as the major product. In this preparation,
care was taken not to leave the compound long on the
TLC plate as it tended to convert to isomer 4.
3.1.3. [H2Os4Ru(CO)12(h6-C6H6)] (2)
Fig. 9. Molecular structure of [Os4(CO)13Ru(h6-C6H6)] (21); the
ellipsoids are shown at the 30% probability level.
CH2Cl2 (20 ml) was added to a sealed flask containing
freshly prepared K2[H2Os4(CO)12] (50 mg, 0.042 mmol)
and an excess of [Ru(h6-C6H6)(MeCN)3][BF4]2 (27 mg,
0.068 mmol). The mixture was warmed slightly using a
water bath and stirred for 20 min to give a brown
solution which was concentrated and then chromato-
graphed by TLC using CH2Cl2:hexane (3:2) as eluent to
give a purple compound [H2Os4Ru(CO)12(h6-C6H6)] (2)
as the major product.
3. Experimental
All the reactions were performed under an atmo-
sphere of dry, oxygen-free nitrogen using standard
Schlenk techniques. Technical grade solvents were
purified by distillation over the appropriate drying
agents and under an inert nitrogen atmosphere prior
to use. Routine separation of products was performed
by thin-layer chromatography (TLC) using commer-
cially-prepared glass plates, pre-coated to 0.25 mm
thickness with Merck Kieselgel 60 F254, as supplied by
Merck, or using laboratory-prepared glass plates coated
to 1 mm thickness with Merck Kieselgel 60 F254. The
complexes [H2Os4(CO)13] [24], [M(h6-C6H6)(MeCN)3]
3.1.4. [H2Os5(CO)12(h6-C6H5Me)] (3)
[Os(C6H5Me)Cl2]2 (20 mg, 0.028 mmol) was sus-
pended in CH2Cl2 and Ag(CF3SO3) (40 mg, 0.183
mmol) was added to it and the mixture stirred for 30
min. The solution was filtered through celite to remove
the AgCl precipitate and the colourless filtrate was
collected into a flask containing freshly prepared
K2[H2Os4(CO)12] (50 mg, 0.042 mmol). The mixture
was stirred for 15 min to give a brown solution which
was concentrated and immediately chromatographed by
TLC using CH2Cl2:hexane (3:2) as eluent to give a
purple compound [H2Os5(CO)12(h6-C6H5Me)] (3) as the
major product.
(Mꢁ
Os [25], Ru [26]) [Os(h6-C6H5Me)Cl2] [27]
/
[AuPPh3][NO3] [28], [(Ph3P)2N][Os4(CO)13Cl] [29],
[Os3(CO)12] [30] and [Ru(h5-C5H5)(CH3CN)3] [31]
were prepared by literature procedures. Other chemicals
were used as purchased without further purification.
The FAB MS were recorded using a Kratos model
902 spectrometer, IR spectra on a PerkinÁElmer 1710
/
FT IR spectrometer, using 0.5 mm NaCl or CaF2 cells,
and 1H, 31P and 13C NMR spectra on a Bruker WH 250
MHz or WH 400 MHz spectrometer. The internal
reference used for the 31P NMR spectra is H3PO4.
3.1.5. [H2Os5(CO)12(h6-C6H6)] (4)
The maroon isomer [H2Os5(CO)12(h6-C6H6)] (1) (30
mg, 0.022 mmol) was left for 24 h in CH2Cl2 (3 ml) and
the resultant brown solution was chromatographed on
thin TLC plates using CH2Cl2:hexane as eluent to give
three bands. The top greenÁbrown band was identified
/
3.1. Preparations
as [H2Os5(CO)13(h6-C6H6)] (6) in 40% yield (12.5 mg,
0.0088 mmol), the middle band (10%, 3 mg, 0.0022
mmol) was found to be the starting material 1, and the
lower band in 40% yield (12.0 mg, 0.0088 mmol) was
identified as [H2Os5(CO)12(h6-C6H6)] (4).
3.1.1. K2[H2Os4(CO)12]
To a solution of [H2Os4(CO)13] (50 mg, 0.044 mmol)
in THF (20 ml), cooled to ꢂ
/
60 8C using a dry iceÁ
/
acetone bath, was added a solution of K/Ph2CO
dropwise whilst stirring. When the blue colour of K/
Ph2CO persisted the cooling bath was removed and the
solution stirred until it turned a yellow colour. The
solvent was removed under vacuo to leave
3.1.6. [H2Os5(CO)12(h6-C6H5Me)] (5)
The purple isomer [H2Os5(CO)12(h6-C6H5Me)] (3) (30
mg, 0.022 mmol) was left for 24 h in CH2Cl2 (3 ml) and
the resultant brown solution was chromatographed on

M.R.A. Al-Mandhary et al. / Inorganica Chimica Acta 350 (2003) 299Á
/
313
309
thin TLC plates using CH2Cl2:hexane as eluent to give
brown band was identified
colour from purple to green. The solution was chroma-
tographed on thin plates using CH2Cl2:hexane (1:1) as
three bands. The top greenÁ
/
as [H2Os5(CO)13(h6-C6H5Me)] (8) in 40% yield (12.4
mg, 0.0088 mmol), the middle band (10%, 3 mg, 0.0022
mmol) was found to be the starting material 3, and the
lower band in 40% yield (12 mg, 0.0088 mmol) was
identified as [H2Os5(CO)12(h6-C6H5Me)] (5).
eluent
to
give
one
major
green
band
[H4Os4Ru(CO)12(h6-C6H6)] (10) in 80% yield (20 mg,
0.016 mmol).
3.1.12. [H2Os5(CO)12(h6-C6H6)PPh2Me] (11)
A drop of PPh2Me was added to a CH2Cl2 (20 ml)
solution of freshly prepared [H2Os5(CO)12(h6-C6H6)] (1)
(20 mg, 0.015 mmol) at r.t. The solution rapidly turned
brown and after 15 min the solution was concentrated
and chromatographed on TLC using CH2Cl2:hexane
3.1.7. [H2Os5(CO)13(h6-C6H6)] (6)
Carbon monoxide was bubbled through a CH2Cl2 (20
ml) solution of freshly prepared [H2Os5(CO)12(h6-
C6H6)] (1) (20 mg, 0.015 mmol) at room temperature
(r.t.) for 30 min and the solution changed from maroon
(3:7) as eluent to give one major greenÁbrown band of
/
to greenÁ
/
brown. The solution was concentrated and
[H2Os5(CO)12(h6-C6H6)PPh2Me] (11) in 85% yield (19.8
mg, 0.013 mmol). {Anal. Found: C, 24.00; H, 1.39. Calc.
chromatographed using CH2Cl2:hexane (1:1) as eluent
to give a quantitative yield (20.4 mg, 0.015 mmol) of
[H2Os5(CO)13(h6-C6H6)] (6).
for [H2Os5(CO)12(h6-C6H6)PPh2Me]: C, 23.75;
1.35%}.
H
3.1.8. [H2Os4Ru(CO)13(h6-C6H6)] (7)
3.1.13. [H3Os4Ru(CO)12(h6-C6H5)PPh2Me] (12)
Carbon monoxide was bubbled through a CH2Cl2 (20
ml) solution of freshly prepared [H2Os4Ru(CO)12(h6-
C6H6)] (2) (25 mg, 0.020 mmol) at r.t. for 30 min and the
solution changed from purple to red. The solution was
concentrated and chromatographed using CH2Cl2:hex-
ane (1:1) as eluent to give a quantitative yield (26 g,
0.020 mmol) of [H2Os4Ru(CO)13(h6-C6H6)] (7). {Anal.
Found: C, 17.44; H, 0.58. Calc. for [H2Os4Ru(CO)13(h6-
C6H6)]: C, 17.47, H 0.62%}.
A drop of PPh2Me was added to a CH2Cl2 (20 ml)
solution of freshly prepared [H2Os4Ru(CO)12(h6-C6H6)]
(2) (25 mg, 0.020 mmol) at r.t. The solution rapidly
turned orange and after 15 min the solution was
concentrated and chromatographed on TLC using
CH2Cl2:hexane (3:7) as eluent to give one major orange
band of [H3Os4Ru(CO)12(h6-C6H5)PPh2Me] (12) in 85%
yield (23.6 mg, 0.016 mmol). {Anal. Found: C, 25.29; H,
1.42. Calc. for [H3Os4Ru(CO)12(h6-C6H5)PPh2Me]: C,
25.19; H 1.43%}.
3.1.9. [H2Os5(CO)13(h6-C6H5Me)] (8)
Carbon monoxide was bubbled through a CH2Cl2 (20
ml) solution of freshly prepared [H2Os5(CO)12(h6-
C6H5Me)] (3) (20 mg, 0.014 mmol) at r.t. for 30 min
3.1.14. [HOs5(CO)12(h6-C6H6)AuPPh3] (13)
A drop of NEt3 was added to a stirred CH2Cl2 (20 ml)
solution of freshly prepared [H2Os5(CO)12(h6-C6H6)] (1)
(20 mg, 0.015 mmol) at r.t. and the solution monitored
by IR until the major peaks had shifted to values
intermediate between the starting material and the
dianion. The solvent was removed under vacuum to
leave a brown oil which was washed several times with
hexane to remove excess NEt3. Excess of AuPPh3NO3
(10 mg, 0.020 mmol) and CH2Cl2 (20 ml) was added to
the brown oil and the mixture stirred for 1 h after which
the solution was concentrated and chromatographed by
TLC using CH2Cl2:hexane (3:2) as eluent to give a top
orange band [HOs5(CO)12(h6-C6H6)AuPPh3] (13) in
40% yield (11.0 mg, 0.006 mmol), a second dark brown
band in 20% yield (tentatively formulated as
[Os5(CO)12(h6-C6H6)(AuPPh3)2], 6.8 mg, 0.003 mmol),
a third green band in 15% yield [H4Os5(CO)12(h6-C6H6)]
(9) (3 mg, 0.002 mmol) and an unidentified polar band.
and the solution changed from purple to greenÁbrown.
/
The solution was concentrated and chromatographed
on thin plates using CH2Cl2:hexane (1:1) as eluent to
give a top greenÁ
brown band of [H2Os5(CO)13(h6-
/
C6H5Me)] (8) in 70% yield (14 mg, 0.010 mmol) and a
bottom brown band of [H2Os5(CO)12(h6-C6H5Me)] (5)
in 30% yield (6 mg, 0.004 mmol).
3.1.10. [H4Os5(CO)12(h6-C6H6)] (9)
H2 was bubbled through a CH2Cl2 (20 ml) solution of
freshly prepared [H2Os5(CO)12(h6-C6H6)] (1) (20 mg,
0.015 mmol) at r.t. for 2 h and the solution changed
colour from maroon to green. The solution was
chromatographed on thin plates using CH2Cl2:hexane
(1:1) as eluent to give one major band [H4Os5(CO)12(h6-
C6H6)] (9) in 80% yield (16.0 mg, 0.012 mmol). {Anal.
Found: C, 25.7; H, 0.7. Calc. for [H2Os5(CO)12(h6-
C6H6)]: C, 15.8; H, 0.7%}.
3.1.15. [HOs4Ru(CO)12(h6-C6H6)AuPPh3] (14)
A drop of NEt3 was added to a stirred CH2Cl2 (20 ml)
solution of freshly prepared [H2Os4Ru(CO)12(h6-C6H6)]
(2) (25 mg, 0.020 mmol) at r.t. and the solution
monitored by IR until the major peaks had shifted to
values intermediate between the starting material and
3.1.11. [H4Os4Ru(CO)12(h6-C6H6)] (10)
H2 was bubbled through a CH2Cl2 (20 ml) solution of
freshly prepared [H2Os4Ru(CO)12(h6-C6H6)] (2) (25 mg,
0.020 mmol) at r.t. for 2 h and the solution changed

310
M.R.A. Al-Mandhary et al. / Inorganica Chimica Acta 350 (2003) 299Á313
/
the dianion. The solvent was removed under vacuum to
leave a brown oil which was washed several times with
hexane to remove excess NEt3. Excess of AuPPh3NO3
(15 mg, 0.029 mmol) and CH2Cl2 (20 ml) was added to
the brown oil and the mixture stirred for 1 h after which
the solution was concentrated and chromatographed by
TLC using CH2Cl2:hexane (3:2) as eluent to give a top
tonated species [Os4(CO)13Ru(h5-C5H5)]ꢂ (19). Subse-
quent addition of 1.5 mol equiv. of [AuPPh3][NO3] (15.7
mg, 0.028 mmol) was followed by stirring for a further
20 min. After removal of solvent, the solid residue was
chromatographed using CH2Cl2Á
/
hexane (1:1) as eluent.
The redÁbrown band 20 (Rfꢁ0.6) was obtained in 60%
/
/
yield (20.3 mg, 0.012 mmol). {Anal. Found: C, 24.86; H,
1.28. Calc. for [Os4(CO)13Ru(h5-C5H5)AuPPh3]: C,
24.71; H, 1.14%}.
orangeÁ
brown band [HOs4Ru(CO)12(h6-C6H6)AuPPh3]
(14) in 70% yield (24.3 mg, 0.014 mmol) and an
unidentified polar band.
/
3.1.20. Reduction of [Os4(CO)13X]ꢂ (Xꢁ
Cl, Br, I)
/
3.1.16. Reaction of [H2Os5(CO)12(h6-C6H6)] (4) with
PPh2Me
[(Ph3P)2N][Os4(CO)13Cl] (50 mg, 0.029 mmol)
[(Ph3P)2N][Os4(CO)13Br] (50 mg, 0.029 mmol) or
[(Ph3P)2N][Os4(CO)13I] (50 mg, 0.028 mmol), respec-
tively, were dissolved in THF. Freshly prepared potas-
sium diphenylketyl was added to the solution until the
blue colour persisted. The solution was stirred until it
turned orange, and the solvent removed under vacuo to
obtain a dark orange residue that was used without
further purification.
To a solution of [H2Os5(CO)12(h6-C6H6)] (4) (20 mg,
0.015 mmol) in CH2Cl2 (30 ml) was added PPh2Me (10
mg, 0.050 mmol) and the solution stirred for 5 h at r.t.,
after which no change in the IR absorptions were
observed. Subsequently, the solution was stirred for a
further 5 days, after which time the solution was
concentrated and chromatographed on TLC using
CH2Cl2:hexane (3:7) as eluent to give one major
greenÁ
/
brown band of [H2Os5(CO)12(h6-C6H6)PPh2Me]
3.1.21. [Os4(CO)13Ru(h5-C5H5)]ꢂ (19)
(11) in 30% yield (7.0 mg, 0.004 mmol) beside the
starting material and decomposition products.
Deoxygenated freshly distilled dichloromethane (30
ml) was added to the sealed Schlenk flask containing
residue from the reduction of [Os4(CO)13X]ꢂ (Xꢁ
Cl,
/
3.1.17. [HOs4(CO)13Ru(h5-C5H5)] (18)
Br, I; 0.029 mmol) and 2.5 mol equiv. of [Ru(h5-
C5H5)(MeCN)3][PF6] (25 mg, 0.072 mmol) was added.
The solution was stirred for 30 min, the solvent
evaporated and the residue chromatographed using
To a solution of [(Ph3P)2N][Os4(CO)13Cl] (50 mg,
0.029 mmol), [(Ph3P)2N][Os4(CO)13Br] (50 mg, 0.029
mmol), or [(Ph3P)2N][Os4(CO)13I] (50 mg, 0.028 mmol),
in 30 ml CH2Cl2 was added 1 mol equiv. of [Ru(h5-
C5H5)(MeCN)3][PF6] (8.8 mg, 0.030 mmol). The solu-
tion was stirred for 30 min and the solvent removed
under vacuo prior to TLC using CH2Cl2:hexane (1:1) as
CH2Cl2 as eluent. The greenÁ
/
brown band (Rfꢁ0.7)
/
was obtained as a major product (30% yield) and the
anion
characterised
spectroscopically
as
[Os4(CO)13Ru(h5-C5H5)]ꢂ (19).
eluent to give
a
dark green major product
0.75) in 40% yield
[HOs4(CO)13Ru(h5-C5H5)] (18) (Rfꢁ
/
3.1.22. [Os4(CO)13Ru(h6-C6H6)] (21)
(15.2 mg, 0.012 mmol). {Anal. Found: C, 16.71; H, 0.44.
Calc. for [HOs4(CO)13Ru(h5-C5H5)]: C, 16.7; H 0.5%}.
Deoxygenated freshly distilled dichloromethane (30
ml) was added to the sealed Schlenk flask containing
residue from the reduction of [Os4(CO)13X]ꢂ (Xꢁ
Cl,
/
3.1.18. Reaction of [HOs4(CO)13Ru(h5-C5H5)] (18)
with phosphines
Br, I; 0.029 mmol) and 1.5 mol equiv. of [Ru(h6-
C6H6)(MeCN)3][BF4]2 (17 mg, 0.044 mmol) was added.
The solution was stirred for 30 min, the solvent removed
under vacuo and the residue chromatographed using
To a solution of [HOs4(CO)13Ru(h5-C5H5)] (15) (20
mg, 0.016 mmol) in CH2Cl2 (30 ml) was added PPh3 (10
mg, 0.038 mmol) and the solution stirred for 5 days,
after which no change in the IR absorptions were
observed. Subsequently, the solution was heated under
reflux for 30 min, the solvent evaporated and the residue
chromatographed using CH2Cl2:hexane as eluent, but
no products could be isolated. The same method was
applied to P(OMe)3 (5 mg, 0.054 mmol) and PPh2Me
(10 mg, 0.050 mmol) with the same result.
CH2Cl2:hexane as eluent. The dark green band (Rfꢁ
/
0.7) was obtained as the major product in 30% yield
(11.5 mg, 0.009 mmol) and characterised spectroscopi-
cally as [Os4(CO)13Ru(h6-C6H6)] (21). {Anal. Found: C,
17.31; H, 0.40. Calc. for [Os4(CO)13Ru(h6-C6H6)]: C,
17.50; H 0.46%}.
3.1.23. Reaction of [Os4(CO)13Ru(h6-C6H6)] (21)
with phosphines
To a solution of [Os4(CO)13Ru(h6-C6H6)] (21) (20 mg,
0.015 mmol) in CH2Cl2 (30 ml), PPh3 (10 mg, 0.038
mmol) was added and the solution stirred for 5 days,
after which no change in the IR absorptions were
observed. Subsequently, the solution was heated under
3.1.19. [Os4(CO)13Ru(h5-C5H5)AuPPh3] (20)
To a solution of [HOs4(CO)13Ru(h5-C5H5)] (15) (25
mg, 0.019 mmol) in THF was added two drops of 1,8-
diazabicyclo[5.4.0]undec-7-ene (DBU). Change in IR
absorption bands indicated the presence of the depro-

Table 11
Crystal data, data collection, structure and refinement parameters for 5, 7, 11, 12, 13, 15, 18, 20, 21
Complex
Molecular for-
mula
5
C19H10O12Os5
7
C19H8O13OsRu
11
12
C31H21O12Os4Pru C36H22AuO12Os5- C49H30ClNO13O-
13
15
18
C
20
18H6O13Os4Ru C36H20AuO13Os4-
0.5(CH2Cl2)
21
C
C31H21O12Os5P×
0.25 CH2Cl2
1588.68
orthorhombic
12.811(3)
20.892(4)
27.895(6)
90
90
90
7466(3)
Pbca
/
19H6O13Os4Ru
P
s4P
1698.9
PRu×
/
M
Crystal system
1381.27
orthorhombic
11.738(6)
11.860(4)
17.646(7)
90
1306.12
monoclinic
11.246(4)
15.228(5)
14.768(4)
90
99.04(2)
90
2497.7(14)
P21/c
1478.32
orthorhombic
22.337(7)
9.553(3)
16.511(5)
90
1825.47
triclinic
12.254(5)
13.104(3)
13.333(6)
81.75(3)
65.25(3)
80.78(3)
2445.4(17)
1292.10
triclinic
8.918(2)
17.407(3)
17.546(4)
113.16(3)
102.55(3)
94.97(3)
2399.1
1792.79
triclinic
1304.11
Monoclinic
9.719(4)
17.873(8)
14.084(5)
90
91.72(3)
90
2445.4(17)
P21/n
triclinic
11.456(4)
14.480(5)
16.783(6)
64.56(2)
88.39(3)
87.16(3)
2510.8(14)
˚
a (A)
10.099(9)
13.726(14)
17.727(17)
105.32(4)
99.37(3)
110.92(6)
2122(4)
P/1
2
2.806
˚
b (A)
˚
c (A)
a (8)
b (8)
g (8)
90
90
90
90
3
˚
U (A )
2456.5(18)
P212121
4
3523.2(19)
Pna21
4
Space group
P
2
3.170
/
1
P
2
2.247
/
1
P/1
Z
4
3.473
8
2.827
4
3.577
4
3.542
Dcalc (g cmꢂ3
Crystal size
(mm)
)
3.735
2.787
0.28ꢃ
/
0.20ꢃ
/
0.05 0.20ꢃ
/0.18ꢃ/0.03 0.15ꢃ
/
0.15ꢃ
/
0.10 0.40ꢃ
/
0.16ꢃ
/
0.02 0.13ꢃ
/
0.10ꢃ
/
0.07 0.32ꢃ/0.30ꢃ/0.24 0.22ꢃ
/0.20ꢃ/0.18 0.36ꢃ/0.29ꢃ/0.25 0.44ꢃ
/
0.18ꢃ0.16
/
Crystal habit
F(000)
Radiation
plate
2400
Mo Ka
plate
2296
Mo Ka
0.71073
20.929
block
5668
Mo Ka
0.71073
17.092
plate
2664
Mo Ka
0.71073
14.897
block
2288
Mo Ka
0.71073
20.471
block
1572
Mo Ka
0.71073
10.269
block
2264
Mo Ka
0.71073
21.787
block
1606
Mo Ka
0.71073
15.882
needle
2288
Mo Ka
0.71073
21.376
˚
Wavelength (A) 0.71073
m (mmꢂ1
Transmission
Temperature (K) 293(2)
)
25.827
0.052Á
/
0.358
0.155Á
293(2)
Siemens R3mV
v Á2u
7.16B
/
0.672
0.1836Á
290(2)
/
0.2798
0.0660Á
290(2)
/
0.7549
0.1761Á
290(2)
/
0.3283
0.1426Á
290(2)
/
0.2562
0.379Á
293(2)
Siemens R3mV
v Á2u
7.06B
/
0.875
0.146Á
293(2)
Stoe-Siemens
v Á
7.04 B
/
0.747
0.065Á
293(2)
Siemens R3mV
v Á2u
50.12 7.36B2uB45.08
/
1.000
Diffractometer
Scan type
Data collection 5.4B
range (8)
Index ranges
Siemens R3mV
v Á2u
2uB
Siemens R3mV
v Á2u
45.10 7.02B
Siemens R3mV
v Á2u
45.08 5.12B
Siemens R3mV
v Á2u
45.08 5.12B
Siemens R3mV
v Á2u
45.08 5.0B2uB
/
/
/
/
/
/
/
/u
/
/
/42.08
/
2uB
/
/
2uB
/
/
2uB
/
/
2uB
/
/
/50.0
/
2uB
/
45.1
/
2uB
/
/
/
ꢂ
/
115
05k 5
l 517
/
h 5
11, ꢂ
/
11,
05
k 5
l 515
3512
/
h 5
16, ꢂ
/
12, 05
155
/
05
k 5
30
5058
/
h 5
22, ꢂ
/
13, 05
/
ꢂ
/
245
105k 5
175l 517
4922
/
h 5
/
24, ꢂ
/
ꢂ
/
15
135k 5
135l 514
5458
/
h 5
/13, ꢂ
/
ꢂ
/
125
145k 5
35l 518
7081
/
h 5
/12, ꢂ
/
05
k 5
l 518
6981
/
h 5
18, ꢂ
/
9, ꢂ
185
/
185
/
ꢂ
/
125
165k 5
115l 521
7577
/
h 5
/
12, ꢂ
/
05
k 5
15
3417
/
h 5
19, ꢂ
/
10, 05
155l 5
/
/
/
/
35
/
/
/
/
/
/
45l 5
/
/
/
/10, ꢂ
/
/
/
14, ꢂ
/
/
/15, ꢂ
/
/
/
/
/
/
15, ꢂ
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
Reflections mea- 2993
sured
Independent re- 2645 (Rint
flections 0.0536)
Parameters, re- 174, 0
straints
ꢁ/
3213 (Rint
0.0262)
174, 0
ꢁ/
4884 (Rint
0.013)
239, 5
ꢁ/
4562 (Rint
ꢁ/
0.038) 5011 (Rint
0.025)
496, 0
ꢁ/
7081 (Rint
0.0093)
631, 0
ꢁ/
6288 (Rint
0.038)
469,0
ꢁ/
7453 (Rint
0.065)
527, 65
ꢁ/
3099 (Rint
ꢁ/0.038)
227, 0
335,0
wR (all data)
R1[I ꢁ2s(I)]
Goodness-of-fit 1.030
Maximum shift 0.000
s
0.2079
0.071
0.1878
0.0663
1.048
0.1563
0.0788
1.019
0.1189
0.0519
1.042
0.1485
0.0542
1.020
0.063
0.035
0.810
0.006
0.1185
0.044
1.089
0.001
0.121
0.045
1.093
0.140
0.045
1.058
0.001
/
0.000
0.001
0.000
0.000
ꢂ/0.003
Extinction coef- 0.0030
ficient
0.0041
Peak, hole
)
2.522, ꢂ
/
2.230
3.133, ꢂ
/
2.909
2.234, ꢂ
/
1.826
1.770, ꢂ
/
1.905
1.998, ꢂ
/
1.949
0.96, ꢂ
/
0.87
1.877, ꢂ
/
2.123
2.848, ꢂ
/
3.058
1.704, ꢂ2.175
/
ꢂ3
˚
(e A
Absolute struc-
ture parameter
ꢂ
/
0.11(9)
0.00(2)

312
M.R.A. Al-Mandhary et al. / Inorganica Chimica Acta 350 (2003) 299Á313
/
reflux for 30 min, the solvent evaporated and the residue
chromatographed using CH2Cl2:hexane as eluent, but
no products could be isolated. The same method was
applied to P(OMe)3 (5 mg, 0.054 mmol) and PPh2Me
(10 mg, 0.050 mmol) with the same result.
Acknowledgements
The authors thank The Government of the Sultanate
of Oman (M.R.A.A), The Overseas Research Students
Awards (M.R.A.A.), The Cambridge Thai Trust (R.B.),
the E.P.S.R.C (C.C., G.P.S.) and the Cambridge Crys-
tallographic Data Centre (G.P.S.) for funding, the EU
for a Human Capital and Mobility Grant (M.C.R. de
A.) and Johnson Matthey PLC for the generous loan of
Os and Ru salts. We are grateful to the University of
Bath for a University Studentship (C.L.D.).
3.2. X-ray crystallography
Suitable single crystals of the clusters 5, 7, 11, 12, 13,
15, 18, 20 and 21 were glued on glass fibres with epoxy
resin, and the assembly mounted on a goniometer head.
This was transferred to a Siemens R3mV diffractometer
or a Stoe-Siemens four-circle diffractometer (for 20) and
data was measured using graphite monochromated Mo
˚
0.71073 A). In each case a semi-
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