Chalcogenide-capped triruthenium clusters: X-ray structures of [Ru 3(CO)6(μ3-CO){P(C4H 3S)3}(μ-dppm)(μ3-O)] and [(μ-H) 2Ru3(CO)6{P(C4H3S) 3}(μ-dppm)(μ3-S)]

Article abstract of DOI:10.1016/j.ica.2011.06.012

Treatment of [Ru₃(CO)₉{P(C₄H ₃S)₃}(μ-dppm)] (1) [dppm = bis(diphenylphosphino) methane] with molecular oxygen in benzene at 60 °C affords oxo-capped [Ru₃(CO)₆(μ₃-CO){P(C₄H ₃S)₃}(μ-dppm)(μ₃-O)] (2), while with elemental sulfur and selenium related chalcogenide-capped clusters [Ru ₃(CO)₆(μ₃-CO){P(C₄H ₃S)₃}(μ-dppm)(μ₃-E)] (3, E = S; 5, E = Se) and bis(chalcogenide) clusters [Ru₃(CO)₆{P(C ₄H₃S)₃}(μ-dppm)(μ₃-E) ₂] (4, E = S; 6, E = Se) result. Reaction of 1 with H₂S in refluxing THF affords the previously reported [(μ-H)₂Ru ₃(CO)₇(μ-dppm)(μ₃-S)] (7) together with the new sulfido-capped dihydride [(μ-H)₂Ru₃(CO) ₆{P(C₄H₃S)₃}(μ-dppm) (μ₃-S)] (8). All new compounds have been characterized by spectroscopic data, and 2 and 8 by single-crystal X-ray diffraction analyses. Oxo-capped 2 consists of a triangular ruthenium framework capped on opposite sides by oxo and carbonyl groups, while 8 consists of a ruthenium triangle by a capping sulfido ligand and two inequivalent bridging hydride ligands.

Full text of DOI:10.1016/j.ica.2011.06.012

Inorganica Chimica Acta 376 (2011) 170–174
Contents lists available at ScienceDirect
Inorganica Chimica Acta
journal homepage: www.elsevier.com/locate/ica
Chalcogenide-capped triruthenium clusters: X-ray structures
of [Ru3(CO)6(
l3-CO){P(C4H3S)3}(l-dppm)(
l3-O)] and
[(l-H)2Ru3(CO)6{P(C4H3S)3}(
l-dppm)(l3-S)]
b
b
Md. Delwar H. Sikder a, Shishir Ghosh a, Shariff E. Kabir a, , Graeme Hogarth , Derek A. Tocher
⇑
a Department of Chemistry, Jahangirnagar University, Savar, Dhaka-1342, Bangladesh
b Department of Chemistry, University College London, 20 Gordon Street, London WC1H OAJ, UK
a r t i c l e i n f o
a b s t r a c t
Article history:
Treatment of [Ru3(CO)9{P(C4H3S)3}(
l
-dppm)] (1) [dppm = bis(diphenylphosphino)methane] with
Received 9 October 2010
Accepted 5 June 2011
Available online 16 June 2011
molecular oxygen in benzene at 60 °C affords oxo-capped [Ru3(CO)6(
3-O)] (2), while with elemental sulfur and selenium related chalcogenide-capped clusters
[Ru3(CO)6( 3-CO){P(C4H3S)3}( -dppm)( 3-E)] (3, E = S; 5, E = Se) and bis(chalcogenide) clusters
[Ru3(CO)6{P(C4H3S)3}( -dppm)( 3-E)2] (4, E = S; 6, E = Se) result. Reaction of 1 with H2S in refluxing
THF affords the previously reported [( -H)2Ru3(CO)7( -dppm)( 3-S)] (7) together with the new
sulfido-capped dihydride [( -H)2Ru3(CO)6{P(C4H3S)3}( -dppm)( 3-S)] (8). All new compounds have been
l3-CO){P(C4H3S)3}(l-dppm)-
(
l
l
l
l
l
l
Keywords:
Ruthenium cluster
Carbonyls
Oxygen-capped
Sulfur-capped
Bridging dppm
Crystal structures
l
l
l
l
l
l
characterized by spectroscopic data, and 2 and 8 by single-crystal X-ray diffraction analyses. Oxo-capped
2 consists of a triangular ruthenium framework capped on opposite sides by oxo and carbonyl groups,
while 8 consists of a ruthenium triangle by a capping sulfido ligand and two inequivalent bridging
hydride ligands.
Ó 2011 Elsevier B.V. All rights reserved.
1. Introduction
tially allows the synthesis of low-valent metal-oxo clusters which
are rare [39–47].
Chalcogenide-containing transition metal clusters serve as
discrete molecular models in furthering our understanding of
extended inorganic solids [1] with the chalcogenide often playing
a pivotal role in cluster aggregation reactions and displaying exotic
coordination modes and geometries [2–19]. Their incorporation
can be achieved in a variety of different ways, with the addition
of tertiary phosphine chalcogenides (R3P@E) [10–12,20–30] and
diaryl dichalcogenides [13,31–36] to low-valent cluster centres
providing particularly useful for the synthesis of sulfido- and sele-
no-containing materials. Both of these take advantage of the rela-
tive frailty of the R3P@E and E–E bonds, and neither is generally
applicable for the synthesis of related oxo-clusters. An attractive
alternative is the addition of elemental chalcogen to transition
metal clusters and while examples of such reactivity are known
they remain relatively scarce [37,38]. Apart from the obvious
atom-efficiency of this method, it also does not result in either
concomitant phosphine incorporation or rely on secondary
element–carbon bond cleavage events. This method also poten-
It has been known for some years now that the zero-valent
triruthenium clusters [Ru3(CO)8( -dppm)2] and [Ru3(CO)6
-dppm)3] both react with molecular oxygen at elevated temper-
atures to afford oxo-capped [Ru3(CO)5( 3-CO)( 3-O)( -dppm)2]
[46] and [Ru3(CO)3( 3-CO)( 3-O)( -dppm)3] [48] respectively. In
contrast, while the mono(dppm) complex, [Ru3(CO)10 -dppm)],
exhibits a rich and diverse chemistry [49] such a reaction does
not occur presumably since the trinuclear centre is not electron-
rich enough to undergo oxidation. We have recently reported the
l
(l
l
l
l
l
l
l
(l
synthesis of [Ru3(CO)9{P(C4H3S)3}(
quantitative yield from the Me3NO initiated reaction of [Ru3-
(CO)10 -dppm)] with tri(2-thienyl)phosphine, and have begun to
l-dppm)] (1), formed in almost
(l
explore its reactivity. Thus, upon mild thermolysis in the presence
of further Me3NO it transforms smoothly into the thiophyne com-
plex [Ru3(CO)7(l-dppm)(l3-g l-P(C4H3S)2] as a result of
2-C4H2S)(
both carbon–hydrogen and carbon–phosphorus bond activation
[50]. In light of the reactivity towards oxygen of dppm-substituted
triruthenium clusters discussed above, we began to consider if 1
was electron-rich enough to undergo oxidation by molecular
oxygen. In this note we report that this is indeed the case, and
moreover show that it reacts smoothly with different group 16 ele-
ments to yield chalcogenide-capped clusters in good yields. To
⇑
Corresponding author.
E-mail address: skabir_ju@yahoo.com (S.E. Kabir).
0020-1693/$ - see front matter Ó 2011 Elsevier B.V. All rights reserved.
doi:10.1016/j.ica.2011.06.012

Md. Delwar H. Sikder et al. / Inorganica Chimica Acta 376 (2011) 170–174
171
complement this work we also report our studies on the reactivity
of 1 towards H2S.
developed three bands. The first band was unreacted 1 (trace)
while the second and third bands afforded [Ru3(CO)6(l3
CO){P(C4H3S)3}( -dppm)( 3-Se)] (5) (8 mg, 26%) as yellow crystals
and [Ru3(CO)6{P(C4H3S)3}( -dppm)( 3-Se)2] (6) (10 mg, 31%) as or-
ange crystals after recrystallization from hexane/CH2Cl2 at 4 °C.
Spectral data for 5: Anal. Calc. for C44H31O7P3Ru3S3Se: C, 42.52;
-
l
l
l
l
2. Experimental
All reactions were carried out under a dry nitrogen atmosphere
using standard Schlenk techniques unless otherwise stated. Re-
agent grade solvents were dried by the standard procedures and
H, 2.51. Found: C, 42.96; H, 2.59%. IR (
mCO, CH2Cl2): 2030 m, 2007
vs, 1994 s, 1959 m, 1652 br cmÀ1 1H NMR (CDCl3): d 7.65–7.63
,
(m, 3H), 7.54 (m, 7H) 7.37 (m, 6H), 7.20–7.03 (m, 13H), 419 (m,
1H), 3.43 (m, 1H), 31P{1H} NMR (CDCl3): d 29.4 (s, 2P), 13.2 (s,
1P); MS (FAB): m/z 1243 (M+). Spectral data for 6: Anal. Calc. for
were freshly distilled prior to use. [Ru3(CO)9{P(C4H3S)3}(l-dppm)]
(1) was prepared according to the published procedure [50]. Ele-
mental selenium and sulfur were purchased from Strem Co., Ltd.,
and Aldrich Co., Ltd., respectively. Infrared spectra were recorded
on a Shimadzu FTIR 8101 spectrophotometer. NMR spectra were
recorded on a Bruker DPX 400 instrument. The chemical shifts
were referenced to residual solvent resonances or 85% H3PO4 in
1H and 31P NMR spectra as appropriate. Elemental analyses were
performed by Microanalytical Laboratories, University College Lon-
don. Fast atom bombardment mass spectra were obtained on a
JOEL SX-102 spectrometer using 3-nitrobenzyl alcohol as matrix
and CsI as calibrant.
C
43H31O6P3Ru3S3Se2: C, 39.91; H, 2.41. Found: C, 40.241; H,
2.48%. IR (
m
CO, CH2Cl2): 2069 s, 2022 vs, 1999 m, 1972 v cmÀ1 1H
,
NMR (CDCl3): d 7.74 (m, 6H), 7.59 (m, 8H) 7.50 (m, 1H), 7.40 (m,
2H), 7.17 (m, 10H), 7.12 (m, 2H), 4.20 (m, 1H), 3.53 (m, 1H).
31P{1H} NMR (CDCl3): d 26.6 (s, 1P), À3.0 (s, 2P). MS (FAB): m/z
1295.
2.4. Reaction of 1 with H2S
H2S gas was bubbled through a THF solution (25 mL) of 1
(40 mg, 0.033 mmol) for 2 min and the resulting solution was re-
fluxed for 2 h. The solvent was removed under reduced pressure
and the residue chromatographed by TLC on silica gel. Elution with
hexane/CH2Cl2 (3:2, v/v) developed two bands. The faster moving
2.1. Reaction of [Ru3(CO)9{P(C4H3S)3}(l-dppm)] (1) with O2
An oxygen saturated benzene solution (25 mL) of 1 (30 mg,
0.025 mmol) was heated at 60 °C for 2 h. The solvent was removed
under reduced pressure and the residue chromatographed by TLC
on silica gel. Elution with hexane/CH2Cl2 (3:2, v/v) developed
two bands. The first band gave a trace amount of unreacted 1.
band gave [(
the slower moving band afforded [(
-dppm)( 3-S)] (8) (12 mg, 31%) as orange crystals from hexane/
l-H)2Ru3(CO)7(l-dppm)(l3-S)] (7) (9 mg, 28%) and
l-H)2Ru3(CO)6{P(C4H3S)3}
(l
l
The
second
band
afforded
[Ru3(CO)6(l3-CO){P(C4H3S)3}
(
l
-dppm)(l
3-O)] (2) (11 mg, 38%) as yellow crystals after recrys-
Table 1
Crystallographic data and structure refinement for 2 and 8.
tallization from hexane/CH2Cl2 at 4 °C. Spectral data for 2: Anal.
Calc. for C44H31O8P3Ru3S3: C, 44.78; H, 2.65. Found: C, 45.08; H,
Compound
2
8
2.72%. IR (
mCO, CH2Cl2): 2030 s, 2005 vs, 1996 sh, 1962 s, 1670 br
Empirical formula
Formula weight
T (K)
C
46H31O9P3Ru3S3
C43H33O6P3Ru3S4
1170.05
150(2)
0.71073
triclinic
cmÀ1 1H NMR (CDCI3): d 7.80 (m, 2H), 7.66 (m, 3H), 7.54 (m,
.
1220.01
150(2)
0.71073
triclinic
1H), 7.43 (m, 1H), 7.35 (m, 9H), 7.26 (m, 10H), 7.13 (m, 3H), 3.67
(m, 1H), 3.85 (m, 1H). 31P{1H} NMR (CDCI3): d 4.58 (s, 1P), 29.5
(s, 2P). MS (FAB): m/z 1179 (M+).
k (Å)
Crystal system
Space group
Unit cell dimensions
a (Å)
b (Å)
c (Å)
ꢀ
ꢀ
P1
P1
2.2. Reaction of 1 with elemental sulfur
11.3825(9)
14.186(1)
14.318(1)
88.066(1)
74.783(1)
88.059(1)
2228.9(3)
2
1.818
1.309
1208
0.48 Â 0.36 Â 0.10
2.32–28.30
À14 6 h P 14
À18 6 k P 18
À18 6 l P 18
19 079
11.042(2)
12.908(2)
17.152(3)
80.547(3)
82.825(3)
70.538(3)
2267.2(7)
2
1.714
1.322
1160
0.46 Â 0.42 Â 0.08
1.21–28.30
À14 6 h P 14
À16 6 k P 17
À22 6 l P 22
19 260
A CH2Cl2 solution (20 mL) of 1 (30 mg, 0.025 mmol) and S8
(2 mg, 0.062 mmol) was heated to reflux for 4 h. A similar chro-
matographic separation to that above developed three bands. The
first band gave unreacted 1 (trace). The second and third bands
a
(°)
b (°)
c
(°)
V (Å3)
afforded [Ru3(CO)6(
41%) as yellow crystals and [Ru3(CO)6{P(C4H3S)3}(
3-S)2] (4) (8 mg, 27%) as red crystals after recrystallization from
hexane/CH2Cl2 at 4 °C. Spectral data for 3: Anal. Calc. for C44H31O7-
P3Ru3S4: C, 44.18; H, 2.61. Found: C, 44.52; H, 2.72%. IR (mCO
CH2Cl2): 2032 m, 2009 vs, 1996 s, 1953 br 1653 w cmÀ1 1H NMR
l
3-CO){P(C4H3S)3}(
l
-dppm)(l3-S)] (3) (12 mg,
Z
q
l
(g cmÀ3
(mmÀ1
)
)
l-dppm)
(l
F(0 0 0)
Crystal size (mm3)
h (°)
,
Index ranges
.
(CDCl3): d 7.64 (m, 3H), 7.53 (m, 7H), 7.35 (m, 6H), 7.17 (M, 9H),
7.06 (m, 4H), 3.90 (m, 1H), 3.46 (m, 1H). 31P{1H} NMR (CDCl3): d
29.0 (s, 2P), 15.2 (s, 1P). MS (FAB): m/z 1195 (M+). Spectral data
for 4: Anal. Calc. for C43H31O6P3Ru3S5: C, 43.03; H, 2.60. Found: C,
Reflections collected
Independent reflections
10 145 (0.0301)
10 295 (0.0275)
(Rint
)
Refinement method
full-matrix least-
squares on F2
0.8802 and 0.5723
full-matrix least-
squares on F2
0.9016 and 0.5814
43.51; H, 2.71%. IR (
mCO, CH2Cl2): 2071 w, 2022 m, 2001 vs, 1967
m, 1943 m cmÀ1 1H NMR (CDCl3): d 7.72 (m, 4H), 7.65 (m, 2H)
.
Max. and min.
transmission
7.59 (m, 6H), 7.49 (m, 2H), 7.40 (m, 4H), 7.19 (m, 9H), 7.11 (m,
2H), 3.0 (m, 2H). 31P{1H} NMR (CDCl3): d 26,7 (s, 1P), 14.7 (s, 2P).
MS (FAB): m/z 1201 (M+).
Data/restraints/
parameters
10 145/0/533
10 295/0/524
Goodness-of-fit on F2
1.072
1.065
Final R indices [I > 2
r
(I)]
R1 = 0.0477,
wR2 = 0.1366
R1 = 0.0536,
wR2 = 0.1444
2.850 and À1.906
R1 = 0.0395,
wR2 = 0.1225
R1 = 0.0439,
wR2 = 0.1307
1.647 and À1.524
2.3. Reaction of 1 with Se
R indices (all data)
A THF solution (50 mL) of 1 (30 mg, 0.025 mmol) and selenium
powder (4 mg, 0.051 mmol) was heated to reflux for 1 h. A similar
work up and chromatographic separation described as above
Largest diff. peak and
hole (e ÅÀ3
)

172
Md. Delwar H. Sikder et al. / Inorganica Chimica Acta 376 (2011) 170–174
CH2Cl2 at 4 °C. Spectral data for 8: Anal. Calc. for C43H33O6P3Ru3S4:
(
(
(
l
l
l
-dppm)(
3-S)2] (4) (27%), while the selenium homologues [Ru3(CO)6
3-CO){P(C4H3S)3}( -dppm)( 3-Se)] (5) [Ru3(CO)6{P(C4H3S)3}(
3-Se)2] (6) were obtained in 26% and 31% yields respec-
l3-S)] (3) (41%) and [Ru3(CO)6{P(C4H3S)3}(l-dppm)
C, 44.14; H, 2.84. Found: C, 44.68; H, 2.97%. IR (mCO, CH2Cl2): 2041
m, 2012 vs, 1982 m, 1949 s cmÀ1. 1H NMR (CDCI3): d 7.59–7.12 (m,
29H), 3.79 (m, 1H), 3.29 (m, 1H), À17.30 (br s, 2H). 31P{1H} NMR
(CDCl3): d 22.0 (br s, 2P), À5.3 (br s, 1P). MS (FAB): m/z 1171.
l
l
l-
dppm)(
l
tively from the reaction of 1 with elemental selenium at 66 °C
(Scheme 1). All new compounds have been characterized by ele-
mental analysis, 1H NMR, 31P{1H} NMR and mass spectroscopic
data. In addition, the solid-state structure of 2 has been deter-
mined by single crystal X-ray diffraction study.
The molecular structure of 2 is depicted in Fig. 1 and selected
bond distances and angles are listed in the caption. The structure
consists of
capped with a triply bridging oxo-ligand on one face [Ru–O(8)
2.051(3)–2.057(3) Å] and a triply bridging carbonyl ligand on the
opposite face [Ru–C(7) 2.148(4)–2.173(5) Å], a bridging dppm, a
terminally coordinated tri(2-thienyl)phosphine ligand and six ter-
minal carbonyl groups. Cluster 2 is structurally similar to that of
2.5. X-ray structure determination of compounds 2 and 8
Single crystals of 2 and 8 suitable for diffraction analysis were
grown by slow diffusion of hexane into a dichloromethane solution
at 4 °C. All geometric and crystallographic data for 2 and 8 were
collected at 150 °C on a Bruker SMART APEX CCD diffractometer
a triangular ruthenium framework symmetrically
using Mo Ka radiation (k = 0.71073). Data reduction and integra-
tion was carried out with SAINT + and absorption corrections were
applied using the program SADABS [51]. Structures were solved by
direct methods and developed using alternating cycles of least-
squares refinement and difference-Fourier synthesis. All non-
hydrogen atoms were refined anisotropically. Hydrogen atoms
were placed in the calculated positions and their thermal parame-
ters linked to those of the atoms to which they were attached
(ridging model). The SHELXTL PLUS V6.10 program package was used
for structure solution and refinement [52]. Final difference maps
did not show any residual electron density of stereochemical sig-
nificance. The details of the data collection and structure refine-
ment are given in Table 1.
the
{dpam = bis(diphenylarsino)methane} which was obtained from
the reaction of [Ru3(CO)8( -dpam)2] with molecular oxygen [48].
Ruthenium–ruthenium distances [Ru–Ru 2.7069(5)–2.7462(5) Å]
are significantly shorter than those in [Ru–Ru 2.8523(3)–
2.8938(3) Å], but comparable to those in [Ru3(CO)5( 3-CO)
-dpam)2( 3-O)] [Ru–Ru 2.670(2)–2.750(2) Å] [48], consistent
related
compound
[Ru3(CO)5(l3-CO)(l-dpam)2(l3-O)]
l
1
l
(l
l
with some level of oxidation of the ruthenium atoms. The dppm li-
gand occupies equatorial sites and Ru–P bond distances involving
the bridging dppm in 2 [Ru–P 2.337(1) and 2.345(1) Å] are compa-
3. Results and discussion
rable to those in [Ru3(CO)10(l-dppm)] [2.322(2) and 2.334(2) Å]
[53]. The terminally coordinated tri(2-thienyl)phosphine ligand is
equatorially bonded to Ru(3). The Ru–P bond distance involving
the terminal monophosphine ligand [Ru(3)–P(3) 2.327(1) Å] is
3.1. Reaction of [Ru3(CO)9(
chalcogenides
l-dppm){P(C4H3S)3}] (1) with
comparable to those found in [Ru3(CO)6(l3-CO)(PPh3)(l-dppm)
Heating a benzene solution of [Ru3(CO)9(
(1) with molecular oxygen resulted in the isolation of [Ru3
(CO)6{P(C4H3S)3}( 3-CO)( -dppm)( 3-O)] (2) in 38% yield after
work-up. A similar reaction of 1 with elemental sulfur at 40 °C
l
-dppm){P(C4H3S)3}]
(l3-S)] [2.353(13) Å] [11]. Considering oxygen as a four-electron
donor, cluster 2 contains 48 cve, as expected for an electron precise
trinuclear cluster containing three metal–metal bonds [54]. There
are few reported examples of triruthenium carbonyl clusters con-
taining triply bridging oxo ligand [46,48,49].
l
l
l
afforded two new compounds; [Ru3(CO)6(l3-CO){P(C4H3S)3}
E
E
(CO)2
Ru PPh 2
(CO)2
Th3P
Th3P
(CO)2
Ru
Ru
Ru PPh 2
+
(CO)2
Ru
P
Ph 2
CO
Ru
P
Ph 2
OC
OC
CO
C
E
O
3, E = S; 5, E = Se
4, E = S; 6, E = Se
S8, CH2Cl2, 80 oC
or
Se, thf, 66 oC
O
CO
(CO)2
Ru PPh 2
Th3P
Ru
OC
O2, 60 oC
C6H6
(CO)3
Ru PPh 2
(CO)2
Ru
Ru
P
Th3P
Ph 2
Ru
(CO)3
P
OC
CO
CO
Ph 2
C
O
1
2
H2S, thf, 66 oC
S
S
(CO)2
Ru PPh 2
Th3P
(CO)2
Ru PPh 2
Ru
Ru
(CO)3
(CO)2
+
Ru
(CO)2
P
H
Ru
(CO)2
P
H
Ph 2
Ph 2
H
H
8
7
Scheme 1.

Md. Delwar H. Sikder et al. / Inorganica Chimica Acta 376 (2011) 170–174
173
which suggest they are isostructural. The 31P{1H} NMR spectra of
both show two resonances in 1:2 ratio, while the mass spectrum
shows parent molecular ions [m/z 1201 for 4 and m/z 1295 for 6]
together with ions due to stepwise loss of six carbonyl groups
which are consistent with our proposed structure.
The reactivity of [Ru3(CO)9(
group 16 elements differs somewhat from that of [Ru3(CO)10
-dppm)] which does not react with dioxygen or elemental sulfur.
Presumably the triruthenium centre is not electron-rich enough to
undergo formal two-electron oxidation. The decacarbonyl
l-dppm){P(C4H3S)3}] (1) towards
(l
a
complex does react with elemental selenium at elevated tempera-
tures but simple addition products akin to 5–6 are not major
products; rather a mixture results which includes [(
-dppm)( 3-Se)], [Ru3(CO)6( -CO){ -PhPCH2PPh(C6H4)}(
and [Ru4(CO)8( -dppm)( 3-Se)2] [56]. Thus the role of the tri(thie-
l-H)2Ru3(CO)7
(l
l
l
l
l3-Se)]
l
l
nyl)phosphine appears to be to both activate the cluster towards
chalcogen addition, while also serving to maintain the cluster
integrity.
3.2. Reaction of [Ru3(CO)9(l-dppm){P(C4H3S)3}] (1) with H2S
Fig. 1. Molecular structure of [Ru3(CO)6(l3-CO){P(C4H3S)3}(l-dppm)(l3-O)] (2)
with thermal ellipsoids drawn at the 50% probability level. Ring hydrogen atoms are
omitted for clarity. Selected bond lengths (Å) and angles (°): Ru(1)–Ru(2) 2.7365(5),
Ru(1)–Ru(3) 2.7462(5), Ru(2)–Ru(3) 2.7069(5), Ru(1)–P(1) 2.3368(12), Ru(2)–P(2)
2.3445(12), Ru(3)–P(3) 2.3266(12), Ru(1)–O(8) 2.051(3), Ru(2)–O(8) 2.057(3),
Ru(3)–O(8) 2.054(3), Ru(1)–C(7) 2.148(4), Ru(2)–C(7) 2.156(5), Ru(3)–C(7)
2.173(5), Ru(2)–Ru(1)–Ru(3) 59.17(1), Ru(3)–Ru(2)–Ru(1) 60.59(1), Ru(2)–Ru
(3)–Ru(1) 60.24(1), Ru(1)–O(8)–Ru(2) 83.6(1), Ru(1)–O(8)–Ru(3) 84.0(1), Ru
(3)–O(8)–Ru(2) 82.4(1), Ru(1)–C(7)–Ru(2) 79.0(2), Ru(1)–C(7)–Ru(3) 78.9(2),
Ru(2)–C(7)–Ru(3) 77.4(2), P(3)–Ru(3)–Ru(1) 98.97(3).
In order to complement the reactivity of 1 towards chalcogens
we have also studied its reaction with H2S. In refluxing THF this
led to the isolation of two sulfur capped triruthenium compounds;
the known [(
substituted analogue [(
(8) in 28% and 31% yields, respectively (Scheme 1). The former also
results from the reaction of [Ru3(CO)10 -dppm)] with H2S [57].
l
-H)2Ru3(CO)7(
l
-dppm)(l3-S)] (7) and a phosphine-
l-H)2Ru3(CO)6{P(C4H3S)3}(
l
-dppm)( 3-S)]
l
(l
Cluster 8 has been characterized by a combination of IR, 1H and
31P{1H} NMR, single-crystal X-ray diffraction and elemental analy-
sis. The molecular structure is shown in Fig. 2 and selected bond
distances and angles are listed in the caption. The molecule con-
sists of a triangular ruthenium framework involving three distinct
metal–metal bonds; [Ru(1)–Ru(2) 2.8597(6), Ru(1)–Ru(3)
2.9185(6) and Ru(2)–Ru(3) 2.7413(5) Å]. The sulfur atom caps
one face quite symmetrically [Ru–S 2.364(1)–2.381(1) Å], bond
lengths being similar to those found in 7. Hydrides were not lo-
cated crystallographically but are believed to span across the
Ru(1)–Ru(2) and Ru(1)–Ru(3) edges in the solid state since these
two edges are significantly longer than the Ru(2)–Ru(3) edge
[58]. The high-field region of the 1H NMR spectrum is not informa-
tive as it shows a broad singlet at d À17.30 which implies that
Spectroscopic data are in accord with the solid-state structure.
The FAB mass spectrum shows a molecular ion peak at m/z 1179
consistent with its formulation and further ions corresponding to
the successive loss of seven carbonyl ligands. The pattern of the
IR is similar to that reported for [Ru3(CO)6(
l3-CO)(PPh3)
(l
-dppm)( 3-S)], synthesized from the reaction of 1 with Ph3P@S
l
[11]. In agreement with the presence of the triply bridging CO,
the spectrum shows a characteristic low energy absorption band
at 1670 cmÀ1. The 31P{1H}NMR spectrum shows two singlets at d
4.6 and 29.5 in a 1:2 ratio. The broad singlet at d 4.6 is assigned
to the phosphorus atom of the tri(2-thienyl)phosphine ligand,
while the singlet at d 29.5 is attributed to the 31P nuclei of the
bridging dppm ligand which are equivalent in solution due to the
rapid movement of the tri(2-thienyl)phosphine between two equa-
torial positions at Ru(3) within the NMR timescale. IR spectra of 3
and 5 are very similar to that of structurally characterized [Ru3
(CO)6(
spectra of both displays two singlets in 1:2 ratio similar to that
of [Ru3(CO)6( 3-CO)(PPh3)( -dppm)( 3-S)] [11]. Their mass spec-
l3-CO)(PPh3)(l-dppm)(l
3-S)] [11] and 2. The 31P{1H} NMR
l
l
l
tra exhibit parent molecular ions at m/z 1195 (for 3) and m/z
1243 (for 5) and further ions due to successive loss of seven car-
bonyl groups which are consistent with our proposed formulation.
We performed an X-ray crystallographic analysis for 5 and partially
determined its molecular structure (Supporting material) [55].
There are some serious absorption problems and disorder associ-
ated with the structure which precludes discussion of the struc-
tural details. However, the structure gives sufficient information
about the geometry of the cluster and the orientation of the ligands
on the cluster surface which shows that it is grossly similar to 2.
Formation of 4 and 6 presumably occurs via secondary addition
of chalcogens to 3 and 5 respectively, although we have not shown
this in independent experiments. They were characterized by com-
paring their spectroscopic data with those of their PPh3 analogues
Fig. 2. Molecular structure of [(l-H)2Ru3(CO)6{P(C4H3S)3}(l-dppm)(l3-S)] (8) with
thermal ellipsoids drawn at the 50% probability level. Ring hydrogen atoms are
omitted for clarity. Selected bond lengths (Å) and angles (°): Ru(1)–Ru(2) 2.8597(6),
Ru(1)–Ru(3) 2.9185(6), Ru(2)–Ru(3) 2.7413(5), Ru(1)–P(1) 2.336(1), Ru(2)–P(2)
2.329(1), Ru(3)–P(3) 2.323(1), Ru(1)–S(1) 2.381(1), Ru(2)–S(1) 2.369(1), Ru(3)–S(1)
2.364(1), Ru(2)–Ru(1)–Ru(3) 56.63(1), Ru(3)–Ru(2)–Ru(1) 62.77(1), Ru(2)–Ru(3)–
Ru(1) 60.60(2), Ru(3)–S(1)–Ru(2) 70.79(3), Ru(3)–S(1)–Ru(1) 75.91(3), Ru(2)–S(1)–
Ru(1) 74.04(3), P(3)–Ru(3)–Ru(1) 104.21(3).
[Ru3(CO)6(PPh3)(l-dppm)(l3-S)2]
and
[Ru3(CO)6(PPh3)(l-
dppm)( 3-Se)2] which were structurally characterized by our
l
group [11]. The carbonyl region of their IR spectra is very similar
to those of their corresponding triphenylphosphine analogues

174
Md. Delwar H. Sikder et al. / Inorganica Chimica Acta 376 (2011) 170–174
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encountered for 7, VT-1H NMR spectra revealing the rapid ex-
change of the hydrides between the non-diphosphine bridged
ruthenium–ruthenium edges on the NMR timescale [57]. The Ru–
P bond distances involving the terminal phosphine [Ru(3)–P(3)
2.323(1) Å] and the bridging dppm [Ru(1)–P(1) 2.336(1) and
Ru(2)–P(2) 2.329(1) Å] are very similar to those found in 1. Com-
pound 8 is structurally similar to that of 7 except in place of one
carbonyl there is a terminal tri(2-thienyl)phosphine ligand on re-
mote ruthenium atom, Ru(3). The FAB mass spectrum of com-
pound 8 exhibit a parent molecular ion at m/z 1171 and other
ions due to stepwise loss of six carbonyl groups which are also con-
sistent with the solid state structure.
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Introduction of the tri(thienyl)phosphine ligand onto [Ru3
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triruthenium centre thus facilitating reactions with group 16 ele-
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ꢀ
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