Reaction of CpV(CO)2(μ-PPh2)Mo(CO)5 and Fe2(μ-S2)(CO)6: Unusual fragmentation and coordination of Fe2(μ-S2)(CO)6

Article abstract of DOI:10.1021/om049821t

Reaction of Fe₂(μ-S₂)(CO)₆ with CpW(CO)₂(μ-PPh₂)Mo(CO)₅ at dichloromethane reflux afforded heterotrimetallic clusters CpW(μ-PPh₂)Mo(CO) ₃(μ-CO)(μ₃-S)₂Fe₂(CO) ₅ (1), Cp(CO)W(μ-PPh₂)Mo(CO) ₃(μ₃-S)₂Fe(CO)₃ (2), CpW(μ-PPh₂)Mo(CO)₃(μ₃-S) ₂Fe₂(μ-CO)(CO)₄ (3), and CpW(CO)(μ₃-S)₂Fe(μ-PPh₂)Fe(CO) ₄Mo(μ₃-S)₂Fe₂(CO)₆ (4). Thermolysis of 1 in dichloromethane produced 3, which was also obtained by the reaction of 2 with Fe₂(CO)₉ at dichloromethane reflux. Reflux of a benzene solution of 3 with norbornadiene (nbd) produced CpW(μ-PPh₂)Mo(CO)(nbd)(μ₃-S)₂Fe ₂(μ-CO)(CO)₄ (5), but the typical reaction without nbd afforded a benzene substitution product, CpW(μ-PPh₂) Mo(η⁶-C₆H₆)(μ₃-S) ₂Fe₂(μ-CO)(CO)₄ (6). Molecular structures of 1-6 were determined by single-crystal X-ray diffraction analyses. Cluster 1 has bitetrahedral geometry, where the Fe₂MoW core is intercepted by an Fe-W bond to FeMoW and Fe₂W units, and each unit is capped by a μ₃-S atom. Cluster 2 is a rare example of square pyramidal geometry with the FeS₂W plane capped by a Mo atom, whereas cluster 3 consists of an Fe₂MoW tetrahedron core with each FeMoW face capped by a μ₃-S atom. Clusters 4-6 possess an Fe₂MoW core geometry similar to that of 3, where carbonyl ligands on the Mo site were replaced by Fe₂(μ-S₂)(CO)₆, nbd, and benzene, respectively.

Full text of DOI:10.1021/om049821t

Organometallics 2004, 23, 3941-3949
3941
Rea ction of Cp W(CO)2(µ-P P h 2)Mo(CO)5 a n d
F e2(µ-S2)(CO)6: Un u su a l F r a gm en ta tion a n d
Coor d in a tion of F e2(µ-S2)(CO)6
Md. Munkir Hossain, Hsiu-Mei Lin, and Shin-Guang Shyu*
Institute of Chemistry, Academia Sinica, Taipei, Taiwan 11529, Republic of China
Received March 11, 2004
Reaction of Fe2(µ-S2)(CO)6 with CpW(CO)2(µ-PPh2)Mo(CO)5 at dichloromethane reflux
afforded heterotrimetallic clusters CpW(µ-PPh2)Mo(CO)3(µ-CO)(µ3-S)2Fe2(CO)5 (1), Cp(CO)W-
(µ-PPh2)Mo(CO)3(µ3-S)2Fe(CO)3 (2), CpW(µ-PPh2)Mo(CO)3(µ3-S)2Fe2(µ-CO)(CO)4 (3), and CpW-
(CO)(µ3-S)2Fe(µ-PPh2)Fe(CO)4Mo(µ3-S)2Fe2(CO)6 (4). Thermolysis of 1 in dichloromethane
produced 3, which was also obtained by the reaction of 2 with Fe2(CO)9 at dichloromethane
reflux. Reflux of a benzene solution of 3 with norbornadiene (nbd) produced CpW(µ-PPh2)-
Mo(CO)(nbd)(µ3-S)2Fe2(µ-CO)(CO)4 (5), but the typical reaction without nbd afforded a
benzene substitution product, CpW(µ-PPh2)Mo(η6-C6H6)(µ3-S)2Fe2(µ-CO)(CO)4 (6). Molecular
structures of 1-6 were determined by single-crystal X-ray diffraction analyses. Cluster 1
has bitetrahedral geometry, where the Fe2MoW core is intercepted by an Fe-W bond to
FeMoW and Fe2W units, and each unit is capped by a µ3-S atom. Cluster 2 is a rare example
of square pyramidal geometry with the FeS2W plane capped by a Mo atom, whereas cluster
3 consists of an Fe2MoW tetrahedron core with each FeMoW face capped by a µ3-S atom.
Clusters 4-6 possess an Fe2MoW core geometry similar to that of 3, where carbonyl ligands
on the Mo site were replaced by Fe2(µ-S2)(CO)6, nbd, and benzene, respectively.
In tr od u ction
that proceed through Fe-Fe bond scission.1b Even its
Fe-S linkage has been exploited for the synthesis of
biologically related compounds that could mimic met-
alloenzymes involved in biological redox processes and
in nitrogenase.6 Recently it has also been used to
prepare macrocycles that contain butterfly transition
metal cluster cores.7 The inorganic disulfide Fe2(µ-S2)-
(CO)6 is very similar in reactivity to organic disulfides
RSSR toward reduction of S-S bonds by sodium metal
and by metal hydrides, nucleophilic cleavage by orga-
nolithium and Grignard reagents, and insertion of
coordinatively unsaturated mononuclear low-valent tran-
sition metals.1b,5a,8 Insertion of single- and triple-bonded
homodinuclear species into the S-S bond of Fe2(µ-S2)-
(CO)6 has been also reported.9 In contrast, insertion
reaction of such heterodinuclear species has not been
The simplest homo- and hetero-dichalcogens of iron
carbonyl, Fe2(µ-EE′)(CO)6 (E ) E′ and E * E′; E, E′ )
S, Se, Te), are now well established.1 Among them Fe2-
(µ-S2)(CO)6, which was first reported by Hieber in
1958,1a has been extensively investigated over the
years.2-5 It has been used as a building block in cluster
growth reactions, and the sulfur bridges in the resulting
clusters provide extra stability. Its chemistry has been
generally initiated by the sulfur atom, through cleavage
of its potentially reactive S-S bond or utilization of lone
pairs on sulfur atoms. Reactions have also been reported
(1) (a) Hieber, W.; Gruber, J . Z. Anorg. Allg. Chem. 1958, 296, 91.
(b) Seyferth, D.; Henderson, R. S.; Song, L.-C. Organometallics 1982,
1, 125. (c) Lesch, D. A.; Rauchfuss, T. B. Inorg. Chem. 1981, 20, 3583.
(d) Mathur, P. Chakrabarty, D.; Hossain, Md. M.; Rashid, R. S.;
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P. Chakrabarty, D.; Hossain, Md. M. J . Orgnomet. Chem. 1991, 401,
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J . Orgnomet. Chem. 1991, 420, 79.
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Henderson, R. S.; Gallagher, M. K. Organometallics 1989, 8, 119. (b)
Song, L.-C.; Lu, G. L.; Hu, Q.-M.; Fan, H.-T.; Chen, Y.; Sun, J .
Organometallics 1999, 12, 3258. (c) Song, L. C.; Kidiata, M.; Wang,
J .-T.; Wang, R.-J .; Wang, H.-J . J . Orgnomet. Chem. 1990, 391, 397.
(d) Bose, K. S.; Sinn, E.; Averill, B. A. Organometallics 1984, 3, 1126.
(e) Don, M. J .; Yang, K. Y.; Bott, S. G.; Richmond, M. G. J . Coord.
Chem. 1996, 40, 273.
(6) King, R. B.; Bitterwolf, T. E. Coord. Chem. Rev. 2000, 206-207,
563.
(7) Song, L.-C.; Fan, H.-T.; Hu, Q.-M. J . Am. Chem. Soc. 2002, 124,
4566.
(8) (a) Seyferth, D.; Henderson, R. S. J . Am. Chem. Soc. 1979, 101,
508. (b) Seyferth, D.; Henderson, R. S.; Song, L.-C. J . Orgnomet. Chem.
1980, 192, C1.
(9) (a) Vahrenkamp, H.; Wucherer, E. J . Angew. Chem., Int. Ed.
Engl. 1981, 20, 680. (b) Braunstein, P.; J ud, J .-M.; Tiripicchio, A.;
Camellini, M. T.; Sappa, E. Angew. Chem., Int. Ed. Engl. 1982, 21,
307. (c) Braunstein, P.; Tiripicchio, A.; Camellini, M. T.; Sappa, E.
Inorg. Chem. 1981, 20, 358. (d) Williams, P. D.; Curtis, M. D.; Duffy,
D. N.; Butler, W. M. Organometallics 1983, 2, 165.
(2) Whitmire, K. H. In Comprehensive Organometallic Chemistry
II; Willkinson, G., Stone, F. G. A., Abel, E., Eds.; Pergamon Press: New
York, 1995; Vol. 7, Chapter 1, Section 1.11.2.2, p 62.
(3) (a) Adams, R. D. Polyhedron 1985, 4, 2003. (b) Adams, R. D.;
Babin, J . E.; Mathur, P.; Natarajan, K.; Wang, J .-G. Inorg. Chem. 1989,
28, 1440. (c) Adams, R. D.; Wang, J .-G. Polyhedron 1989, 8, 1437. (d)
Adams R. D.; Babin, J . E.; Estrada, J .; Wang, J .-G.; Hall, M. B.; Low,
A. A. Polyhedron 1989, 8, 1885. (e) Mathur, P.; Mukhopadhyay, S.;
Ahmed, M. O.; Lahiri, G. K.; Chakraborty, S.; Walawalker, M. G.
Organometallics 2000, 19, 5787. (f) Mathur, P.; Mukhopadhyay, S.;
Lahiri, G. K.; Chakraborty, S.; Tho¨ne, C. Organometallics 2002, 21,
5209. (g) Scheer, M.; Umbarkar, S. B.; Chatterjee, S.; Trivedi, R.;
Mathur, P. Angew. Chem., Int. Ed. 2001, 40, 376.
(4) (a) Westmeyer, M. D.; Rauchfuss, T. B. Inorg. Chem. 1996, 35,
7140. (b) Westmeyer, M. D.; Galloway, C. P.; Rauchfuss, T. B. Inorg.
Chem. 1994, 33, 4615. (c) Day, V. W.; Lesch, D. A.; Rauchfuss, T. B. J .
Am. Chem. Soc. 1982, 104, 1290.
10.1021/om049821t CCC: $27.50 © 2004 American Chemical Society
Publication on Web 07/10/2004

3942 Organometallics, Vol. 23, No. 16, 2004
Hossain et al.
Sch em e 1
reported. Here we report an insertion reaction between
Fe2(µ-S2)(CO)6 and the phosphido-bridged hetero-
obtained by insertion of coordinatively unsaturated
metal species into the S-S bond of Fe2(µ-S2)(CO)6.
Cluster 2 is a rare example of a heterotrimetallic cluster
dinuclear CpW(CO)2(µ-PPh2)Mo(CO)5, which has a weak
Mo-W bond and labile CO ligands on Mo for further
reaction.10 This reaction leads to an unusual fragmenta-
tion and coordination of Fe2(µ-S2)(CO)6, both of which,
to our knowledge, are the first examples of such reactiv-
ity of the diiron complex. The substitution reactions on
3 by norbornadiene and benzene are also described.
Resu lts a n d Discu ssion
Rea ction of F e2(µ-S2)(CO)6 w ith Cp W(CO)2(µ-
P P h 2)Mo(CO)5. When a dichloromethane solution of
Fe2(µ-S2)(CO)6 and CpW(CO)2(µ-PPh2)Mo(CO)5 was re-
fluxed for about 20 h, clusters 1-4 and a known
compound Fe3(µ-S)2(CO)9 were obtained (Scheme 1).
Control experiments established that Fe2(µ-S2)(CO)6
alone did not convert to Fe3(µ-S)2(CO)9 and that Fe3(µ-
F igu r e 1. ORTEP drawing of 1. Hydrogen atoms are
omitted.
S)2(CO)9 did not react with CpW(CO)2(µ-PPh2)Mo(CO)5
under identical conditions; therefore, they formed di-
rectly from Fe2(µ-S2)(CO)6 and CpW(CO)2(µ-PPh2)Mo-
(CO)5.
Cluster 1 has a bitetrahedral geometry (Figure 1)
with FeMoWS and Fe2WS tetrahedra, where each S
atom is coordinated to metals in a µ3-S mode. The
molecular structure of 2 (Figure 2) reveals a square
pyramidal geometry, with the FeS2W plane capped by
a Mo atom. Each sulfur atom is coordinated to FeWMo
atoms in a µ3-S mode. There are a few examples of
heterobimetallic square pyramidal clusters with an
Fe2M(µ3-S)2 core (M ) Co, W, Ru),11 which were
(10) Shyu, S.-G.; Hsu, J .-Y.; Lin, P.-J .; Wu, W.-J .; Peng, S.-M.; Lee,
G.-H.; Wen, Y.-S. Organometallics 1994, 13, 1699.
(11) (a) Adams, R. D.; Babin, J . E.; Wang, J .-G.; Wu, W. Inorg. Chem.
1989, 28, 703. (b) Wakatsuki, Y.; Yamazaki, H.; Chen, G. J . Organomet.
Chem. 1988, 347, 151. (c) Mathur, P.; Chakrabarty, D.; Mavunkal, I.
J . J . Cluster Sci. 1993, 4, 351.
F igu r e 2. ORTEP drawing of 2. Hydrogen atoms are
omitted.

Unusual Fragmentation of Fe2(µ-S2)(CO)6
Organometallics, Vol. 23, No. 16, 2004 3943
Mo triangle attached to two apical µ3-S. This arrange-
ment provides striking contrast with the generally
observed square planar geometry in WFe2(CO)9(PMe2-
Ph)(µ3-S)2,11a (C5H4COOMe)CoFe2(CO)2(µ3-S)2,11b Cp*Co-
(µ3-S)2 Fe2(CO)6,5a and Fe2Ru(µ3-S)2(CO)9.11c
F or m a tion of Clu ster s 1 a n d 2: Role of th e
P h osp h id o Br id ge. It has been reported that during
the reaction between Fe3(µ-Te)2(CO)9 and dinuclear Cp2-
Mo2(CO)6, Fe3(µ-Te)2(CO)9 converted to more reactive
Fe2(µ-Te2)(CO)6, which further reacted with Cp2Mo2-
(CO)6 to form a five-vertex, arachno cluster, Cp2Mo2-
FeTe2(CO)7.14 Rauchfuss proposed that the formation
of Cp2Mo2FeTe2(CO)7 was possibly by the loss of an
even-electron Fe(CO)n fragment from either octahedral
or bitetrahedral Mo2Fe2Te2 clusters.14 However, during
the reaction of Fe2(µ-S2)(CO)6 or Fe3(µ-S)2(CO)9 with
Cp2Mo2(CO)6 in identical conditions, the cis isomer
(Braunstein isomer), Cp2Mo2Fe2S2(CO)8, was observed
instead of Cp2Mo2FeS2(CO)7, the analogue of Cp2Mo2-
FeTe2(CO)7.14 Rauchfuss also reported that under the
conditions of his experiment, the expected trans isomer
(Curtis isomer) is converted into the cis form. The cis
and trans isomers of Cp2Mo2Fe2S2(CO)8 were obtained
from Cp2Mo2(CO)4 and Fe2(µ-S2)(CO)6.9b,d
F igu r e 3. ORTEP drawing of 3. Hydrogen atoms are
omitted.
The Braunstein isomer of Cp2Mo2Fe2S2(CO)8 re-
sembles in structure that of Cp2Mo2Fe2Te2(CO)7, which
is a thermolytic product of Cp2Mo2FeTe2 (CO)7. He then
proposed that formation of the Braunstein-Curtis
F igu r e 4. ORTEP drawing of 4. Hydrogen atoms are
omitted.
14
isomers may also occur via a Mo2FeS2 intermediate
similar to Mo2FeTe2,14 but it is unstable compared to
Mo2FeTe2.14 Here we observed the MoWFeS2 core
cluster 2, when Fe2(µ-S2)(CO)6 reacted with the het-
with square pyramidal geometry. There were no reports
of square pyramidal heterotrimetallic clusters with
bridging sulfur owing to a lack of availability of het-
erodinuclear building blocks such as MM′(µ-S2)(CO)6
except the recent reports of the CpMnCo(µ-S2)(CO)5.12
The tetrametallic cluster 3 consists of an Fe2MoW
tetrahedron core with each FeMoW face capped by a
µ3-S atom. Its core structure (Figure 3) resembles more
erodinuclear phosphido-bridged CpW(CO)2(µ-PPh2)Mo-
(CO)5. It has a five-vertex nido structure rather than a
five-vertex arachno geometry like Cp2Mo2FeTe2(CO)7.
The bridged phosphido ligand in CpW(CO)2(µ-PPh2)Mo-
(CO)5 may prevent the cleavage of the Mo-W bond
during the reaction and lead to a stable 2 with a nido
structure. We also isolated bitetrahedral 1, which is an
14
that of Cp2Mo2Fe2Se2(CO)713 and Cp2Mo2Fe2Te2(CO)7
than that of Cp2Mo2Fe2S2(CO)8.9b,d
The novel hexametallic cluster 4 has a core structure
(Figure 4) similar to that of 3, but with the bridging
ligands PPh2 on MoW and CO on iron atoms having
interchanged their positions. Ligand PPh2 bridges the
iron atoms, but CO is coordinated to tungsten as a
terminal ligand. Moreover, the carbonyl ligands on Mo
were replaced by another molecule of Fe2(µ-S2)(CO)6.
The coordination of this molecule to Mo is unique and
unusual; it occupies four coordination sites on Mo by
using all the Fe2S2 atoms. The resulting geometry of
Fe2S2Mo is that of a trigonal bipyramid, with the Fe2-
14
analogue of the proposed bitetrahedral Mo2Fe2Te2
intermediate in the reaction between Fe3(µ-Te)2(CO)9
and Cp2Mo2(CO)6. Stability in 1 may also be caused by
the bridged phosphido ligand.
Mech a n ism of th e F or m a tion of 3. When a dichlo-
romethane solution of 1 was refluxed for 20 h, 3 was
the sole product. It is realized that 1 is rearranged to 3
after loss of one carbonyl ligand compensated for by
formation of an Fe-Mo bond, and the bridging carbonyl
shifted from the Fe-Mo to Fe-Fe position with break-
ing an Fe-S bond and making a Mo-S bond. On the
other hand 2 differs from 1 and 3 by an Fe(CO)n
fragment (Scheme 2). Thus, this rearrangement of 1 to
3 may occur via 2 by dissociation-reassociation of
Fe(CO)n. It is further supported by the conversion of 2
to 3 with Fe2(CO)9. We did not observe 2, as an
(12) (a) Adams, R. D., Miao, S. Organometallics 2003, 22, 2492. (b)
Adams, R. D.; Captain, B.; Kwon, O.-S.; Miao, S. Inorg. Chem. 2003,
22, 3356.
(13) Mathur, P.; Hossain, Md. M.; Rheingold, A. L. Organometallics
1994, 13, 3909.
(14) Bogan, L. E., J r.; Rauchfuss, T. B.; Rheingold, A. L. J . Am.
Chem. Soc. 1985, 107, 3843.

3944 Organometallics, Vol. 23, No. 16, 2004
Hossain et al.
Sch em e 2
Sch em e 3
intermediate during thermolsis of 1 to 3 may be due to
two reasons. First, the dissociation-reassociation of
Fe(CO)n is spontaneous and stoichimetric. Second there
was no acceptor of Fe(CO)n other than the dissociated
product 2 in the reaction medium. However, we isolated
2 during reaction between Fe2(µ-S2)(CO)6 and CpW-
(CO)2(µ-PPh2)Mo(CO)5. This is because some of the
dissociated Fe(CO)n from 1 also reacted with Fe2(µ-S2)-
(CO)6 and formed Fe3(µ-S)2(CO),9 leaving some of 2
intact. This is further supported by the formation of Fe3-
(µ-S)2(CO)9 and 2 together with 3, when 1 was thermo-
lyzed in identical conditions in the presence of Fe2(µ-
S2)(CO)6. In support of this fragmentation mechanism,
we could mention the reversible dissociation of an
Fe(CO)3 vertex of Fe4(PPh)2(CO)12 to produce Fe3(PPh)2-
(CO)9.15 Formation of intermediates 1 and 2 for 3 also
supports Rauchfuss’ proposal about the intermediates
14
14
bitetrahedral Mo2Fe2Te2 and Mo2FeS2 for the reac-
tions of Fe3(µ-Te)2(CO)9 with Cp2Mo2(CO)6 and Fe2-
(µ-S2)(CO)x (x ) 6, 9) with Cp2Mo2(CO)x (x ) 4, 6),9b,d,14
respectively.
Rea ction of 3 w ith Nor bor n a d ien e (n bd ), Ben -
zen e, a n d F e2(µ-S2)(CO)6. When a benzene solution
of 3 is refluxed with nbd, cluster 5 is an isolated product,
but the same reaction without nbd afforded cluster 6
(Scheme 3). The core Fe2MoW of 5 and 6 has a geometry
(Figures 5 and 6) similar to that of 3. Basically both of
them are substitution products of 3 where carbonyl
ligands on Mo are replaced by nbd and C6H6, respec-
tively. This indicates that carbonyl ligands on the Mo
site are more labile than those on Fe sites. Carbonyl
ligands are π acceptors. Due to the high oxidation state
of the Mo atom in 3, the availability of electron density
on it for back-donation to carbonyl ligands is reduced;
therefore the Mo-C bond is weakened and becomes
more labile for substitution. Formation of 4 was ex-
pected from the reaction between 3 and Fe2(µ-S2)(CO)6.
However, a control reaction of 3 with Fe2(µ-S2)(CO)6 did
not produce 4.
in 1 is intercepted by a fifth diagonal Fe1-W1
bond, resulting in bitetrahedral Fe1Fe2W1S2 and
Fe1Mo1W1S1. Overall, the structure of 1 is similar to
WFe3(CO)11(PMe2Ph)(µ3-S)2.11a The peripheral Fe-W
bonds in these two clusters are comparable; however,
the diagonal Fe1-W1 (2.7516(19) Å) in 1 is longer than
the diagonal Fe2-W (2.667(1) Å) in WFe3(CO)11(PMe2-
Ph)(µ3-S)2. Cluster 2 consisits of 50 valence electrons,
X-r a y Str u ctu r es of Clu ster s 1-6. Molecular struc-
tures of 1-6 were determined by single-crystal X-ray
diffraction analyses, and they are shown in Figures 1-6,
respectively. The experimental data are summarized in
Table 1. Selected bond distances and bond angles are
listed in Table 2. Cluster 1 contains 62 valence electrons
assuming each sulfur atom serves as a four-electron
donor. To obey the 18e rule, tetrametallic 1 possesses
five metal-metal bonds. Thus, the square Fe1Fe2Mo1W1
(15) (a) Vahrenkamp, H.; Wolters, D. J . Organomet. Chem. 1982,
224, C17. (b) Vahrenkamp, H.; Wucherer, E. J .; Wolters, D. Chem. Ber.
1983, 116, 1219.
F igu r e 5. ORTEP drawing of 5. Hydrogen atoms are
omitted.

Unusual Fragmentation of Fe2(µ-S2)(CO)6
Organometallics, Vol. 23, No. 16, 2004 3945
Ta ble 1. Su m m a r y of Cr ysta l Da ta for 1-3 a n d 4-6
1
2
3
formula
fw
C
26H15O9Fe2PS2MoW
C24H15O7S2PFeMoW
846.1
C25H15O8S2PFe2MoW
929.95
957.96
space group
a [Å]
b [Å]
P 21/n
P 1 21 1
8.943(3)
9.702(2)
15.436(3)
P1 21/c 1
9.9693 (15)
14.942(2)
9.6344(17)
24.805(4)
12.414(2)
c[Å]
19.291(3)
R [deg]
â [deg]
γ [deg]
V [Å3]
92.318(15)
96.58(2)
91.221 (13)
2964.3(9)
2.147
4
1330.5(6)
2.112
1
2872.9 (8)
2.150
4
F(calcd) [Mg m-3
Z
]
cryst dimens [mm]
temp
λ(Mo KR) [Å]
2θ range [deg]
scan type
no. of reflns
no. of obsd reflns
no.of params refined
R
0.25 × 0.20 × 0.14
0.24 × 0.20 × 0.14
room temperature
0.71073
50.0
ω
2687
2517 (>2.5σ(I))
339
0.0526
0.24 × 0.12 × 0.09
room temperature
0.71073
50.0
ω
5338
5034 (>2.0σ(I))
421
0.0257
room temperature
0.71073
50
ω
5525
5200 (>2.0σ(I))
380
00395
Rw
GoF
0.1040
1.065
-1.762, 1.598
0.1263
1.019
-2.379, 2.828
0.0558
1.043
-0.463, 0.482
D
map min., max. [e/Å3]
4
5
6
formula
fw
C
29H17O11PS4Cl2Fe4MoW
C30H23O6S2PFe2MoW
966.08
C42H37O5S2PFe2MoW
1108.32
1274.76
space group
a [Å]
b [Å]
P 21/n
P 1 21/c 1
10.5679(13)
19.380(3)
P 1 21/n 1
10.400(2)
19.407(4)
20.383(4)
10.2336(14)
16.749(3)
23.139(4)
c[Å]
15.794(3)
R [deg]
â [deg]
γ [deg]
V [Å3]
102.486(14)
93.652(13)
91.41(3)
3872.3(11)
2.183
4
3228.1(10)
1.979
4
4112.5(14)
1.790
6
F(calcd) [Mg m-3
Z
]
cryst dimens [mm]
temp
λ(Mo KR) [Å]
2θ range [deg]
scan type
no. of reflns
no. of obsd reflns
no.of params refined
R
0.25 × 0.10 × 0.06
0.19 × 0.17 × 0.07
room temperature
0.71073
50.0
ω
5666
5448 (>2.0σ(I))
371
0.0667
0.44 × 0.38 × 0.28
room temperature
0.71073
50.0
ω
7665
7235 (>2.0σ(I))
487
0.0317
room teperature
0.71073
50.0
ω
7203
6784 (>2.0σ(I))
519
0.038
Rw
0.096
0.1850
0.0783
GoF
D
1.059
-1.669, 1.786
0.966
-1.216, 5.197
1.056
-0.838, 0.850
map min., max. [e/Å3]
number of electrons expected for a normal trinuclear
triangle cluster is 48; the excess two electrons in 2
cleaved one metal-metal bond and formed square
pyramidal 2. It is structurally similar to WFe2(CO)9-
(PMe2Ph)(µ3-S)2,11a (C5H4COOMe)CoFe2(CO)2(µ3-S)2,11b
and Fe2Ru(µ3-S)2(CO)9.11c Cluster 3 is electron precise
with 60 valence electrons. Thus, the tetranuclear 3 has
six metal-metal bonds to satisfy 18e for each metal. It
has two electrons less than 1 (62e) after loss of one CO
compensated for by an extra metal-metal bond. Both
5 and 6 are also electron precise, with 60 valence
electrons, similar to that of 3, where two CO for 5 and
three CO for 6 on the Mo site were substituted by a four-
electron donor nbd and a six-electron donor benzene,
respectively. Therefore, they are also structurally very
similar to 3. In comparison with the Braunstein isomer
of Cp2Mo2Fe2S2(CO)8, clusters 3, 5, and 6 have an Fe-
Fe bond bridged by CO instead of any semitriply bridged
CO, both of those being seen on Mo atoms in Cp2-
F igu r e 6. ORTEP drawing of 6. Hydrogen atoms are
omitted.
which satisfies the 18e rule, providing a trinuclear two
metal-metal bonded square pyramidal geometry. The
Mo2Fe2S2(CO)8.9b,d The Fe-Fe bond lengths in
3

3946 Organometallics, Vol. 23, No. 16, 2004
Ta ble 2. Selected Bon d Len gth s (Å) a n d Bon d An gles (d eg) for 1-6
Hossain et al.
1
2
3
4
5
6
Bonds
Mo1-W1
Mo1-Fe1
Mo1-Fe2
Mo1-Fe3
Mo1-Fe4
W1-Fe1
W1-Fe2
Fe1-Fe2
Fe3-Fe4
Mo1-S1
Mo1-S2
Mo1-S3
Mo1-S4
W1-S1
2.9155(13)
2.814(2)
2.865(3)
2.753(4)
2.7196(6)
2.8445(9)
2.8374(9)
2.8172(9)
2.7622(16)
2.7555(15)
2.8919(16)
2.8967(17)
2.7724(14)
2.7819(14)
2.5673(19)
2.527(2)
2.321(2)
2.320(2)
2.308(3)
2.299(3)
2.698(3)
2.830(4)
2.879(4)
2.6732(6)
2.8304(12)
2.8181(12)
2.7516(19)
2.834(2)
2.592(3)
2.7595(8)
2.7659(8)
2.4192(10)
2.758(4)
2.768(4)
2.517(6)
2.7335(9)
2.7627(9)
2.4226(12)
2.448(4)
2.475(7)
2.503(7)
2.4887(13)
2.4668(13)
2.443(7)
2.501(7)
2.4146(16)
2.4088(15)
2.298(3)
2.295(3)
2.281(4)
2.290(4)
2.154(4)
2.484(5)
2.420(9)
2.258(8)
2.251(7)
2.3315(13)
2.3268(12)
2.1738(15)
2.321(2)
2.321(2)
2.238(3)
2.450(7)
2.376(6)
2.219(7)
2.3416(14)
2.3410(14)
2.1760(17)
W1-S2
Fe1-S1
Fe1-S2
Fe2-S2
Fe3-S3
F3-S4
Fe4-S3
Fe4-S4
Mo1-P1
W1-P1
Fe1-P1
Fe2-P1
Fe1-C1
Fe1-C2
Fe1-C3
Fe2-C3
Fe2-C4
Fe2-C5
2.1751(14)
2.244(3)
2.298(3)
2.289(3)
2.281(3)
2.298(3)
2.204(7)
2.1749(16)
2.461(3)
2.438(4)
2.496(7)
2.403(5)
2.5186(13)
2.4580(13)
2.549(7)
2.452(6)
2.4359(14)
2.4117(16)
2.191(3)
2.202(3)
1.733(16)
1.763(15)
2.121(16)
1.79(3)
1.83(3)
1.80(2)
1.750(6)
1.782(6)
1.956(6)
1.947(6)
1.757(6)
1.793(6)
1.64(3)
1.87(3)
2.00(3)
1.94(3)
1.72(3)
1.78(3)
1.734(8)
1.775(7)
1.923(60
1.924(6)
1.773(6)
1.748(7)
1.746(17)
1.759(17)
Angles
116.12(4)
75.64(4)
58.43(3)
49.69(4)
95.52(4)
75.96(4)
57.90(3)
95.49(3)
49.65(3)
57.95(3)
113.96(4)
114.13(3)
62.55(2)
62.29(2)
51.93(2)
105.82(4)
71.86(14)
52.96(3)
47.53(3)
90.33(4)
72.45(4)
53.04(3)
90.33(4)
47.79(3)
55.81(3)
109.28(4)
109.86(7)
59.41(2)
59.66(2)
50.40(2)
110.88(4)
54.86(4)
57.62(4)
64.17(3)
64.65(3)
58.0541(15)
S1-W1-S2
102.90(12)
107.85(12)
54.47(9)
52.79(9)
74.49(10)
83.27(12)
101.02(9)
53.03(9)
48.28(9)
53.85(8)
84.74(9)
128.81(9)
59.46(9)
112.85(5)
55.27(6)
74.3(2)
74.12(17)
54.57(18)
104.12(5)
115.0(2)
113.92(5)
74.52(6)
57.11(4)
50.05(4)
95.27(4)
74.44(6)
56.96(4)
95.50(4)
49.61(4)
56.97(3)
113.8(4)
113.11(4)
63.12(3)
62.43(3)
52.30(3)
108.93(5)
72.79(5)
54.51(4)
48.22(4)
92.23(5)
72.81(5)
54.56(4)
91.54(4)
48.40(4)
56.10(4)
109.78(4)
110.48(4)
59.48(2)
60.34(2)
50.79(3)
110.53(6)
55.57(4)
55.85(4)
64.47(3)
64.34(4)
57.40(2)
S1-W1-P1
73.2(2)
56.42(17)
50.01(17)
97.19(18)
76.8(2)
58.65(17)
97.28(8)
50.05(17)
59.10(18)
114.09(19)
116.14(19)
62.49(9)
63.57(9)
54.19(12)
110.8(2)
71.6(2)
S1-W1-Mo1
S1-W1-Fe1
S1-W1-Fe2
S2-W1-P1
S2-W1-Mo1
S2-W1-Fe1
S2-W1-F2
52.63(3)
51.19(6)
95.89(6)
111.0(3)
55.78(19)
52.61(6)
96.17(7)
51.20(7)
P1-W1-Mo1
P1-W1-Fe1
P1-W1-Fe2
Mo1-W1-Fe1
Mo1-W1-Fe2
Fe1-W1-Fe2
S1-Mo1-S2
S1-Mo1-P1
S1-Mo1-W1
S1-Mo1-Fe1
S1-Mo1-Fe2
S2-Mo1-P1
S2-Mo1-W1
S2-Mo1-Fe1
S2-Mo1-Fe2
P1-Mo1-W1
P1-Mo1-Fe1
P1-Mo1-Fe2
W1-Mo1-Fe1
W1-Mo1-Fe2
Fe1-Mo1-Fe2
S1-Fe1-Fe2
S1-Fe1-W1
S1-Fe1-Mo1
Fe2-Fe1-W1
Fe2-Fe1-Mo1
W1-Fe1-Mo1
S2-Fe1-Mo1
S2-Fe2-Fe1
S2-Fe2-W1
S2-Fe2-Mo1
Fe1-Fe2-W1
55.75(18)
59.22(3)
58.96(3)
55.06(5)
104.69(9)
73.0(2)
72.7(2)
54.85(14)
50.82(17)
102.50(12)
49.81(8)
50.80(9)
52.63(6)
51.35(7)
96.60(7)
56.66(16)
49.09(17)
94.48(9)
72.9(2)
105.3(2)
53.08(19)
50.44
52.65(6)
96.48(7)
51.61(7)
54.23(16)
92.62(18)
47.74(17)
55.64(15)
108.72(18)
109.36(18)
59.80(9)
59.40(10)
52.30(12)
111.5(2)
57.8(2)
53.12(9)
82.99(9)
52.71(14)
121.78(18)
57.37(4)
80.86(9)
59.58(3)
59.88(3)
55.46(4)
104.36(8)
53.91(7)
54.08(7)
62.66(4)
62.14(5)
61.19(3)
79.81(11)
53.35(9)
56.27(10)
63.98(6)
124.73(8)
63.17(5)
104.22(10)
56.79(10)
52.67(9)
58.20(17)
59.0(2)
56.31(19)
63.10(12)
64.85(13)
57.71(9)
110.43(5)
54.61(4)
57.14(4)
63.90(3)
104.23(8)
53.73(7)
54.14(7)
62.28(4)
109.6(2)
55.70(19)
57.03(9)
62.71(13)
109.85(5)
55.06(4)
55.92(4)
63.23(3)
60.75(6)

Unusual Fragmentation of Fe2(µ-S2)(CO)6
Organometallics, Vol. 23, No. 16, 2004 3947
Ta ble 2 (Con tin u ed )
1
2
3
4
5
6
Fe1-Fe2-Mo1
W1-Fe2-Mo1
64.95(3)
58.056(19)
75.45(5)
74.85(4)
62.40(4)
61.16(3)
74.90(8)
74.57(8)
63.86(13)
57.03(9)
72.2(2)
64.87(4)
57.23(2)
74.38(5)
75.93(5)
Fe1-S1-W1
Fe1-S1-Mo1
Fe1-S2-W1
Fe1-S2-Mo1
Fe2-S2-W1
Fe2-S2-Mo1
W1-S1-Mo1
W1-S2-Mo1
W1-P1-Mo1
Fe2-C3-Fe1
73.87(10)
72.93(11)
73.76(10)
100.3(3)
71.0(2)
70.6(2)
102.5(3)
74.6(2)
79.05(11)
75.73(10)
73.03(10)
75.73(4)
75.08(5)
68.61(3)
69.06(4)
66.24(3)
76.6(2)
75.06(8)
74.25(8)
74.75(7)
74.73(7)
74.2(2)
75.2(2)
66.92(19)
67.12(17)
65.26(17)
79.2(10)
75.33(5)
75.68(5)
68.38(4)
68.48(4)
66.93(4)
78.1(2)
70.58(17)
71.1(2)
71.54(18)
Ta ble 3. Bon d Dista n ces for a F ew Br id ged Bin u clea r Molybd en u m a n d Tu n gsten Com p lexes
compound
bridge no.
M-M (Å)
M-X-M (deg)
ref
Cp(CO)2W(µ-PPh2)W(CO)5
1
1
1
2
2
3
3
3
3
3
3
3
4
4
3.1942(12)
3.2054(16)
3.131(1)
2.972(1)
2.936(1)
2.8589(6)
2.8427(14)
2.8382(13)
2.8063(20)
2.8040(9)
2.779(4)
81.02(18)
81.31(14)
79.49(1)
20
10
21
22
23
24
24
24
24
25
25
26
27
28
Cp(CO)2W(µ-PPh2)Mo(CO)5
Cp(CO)2Mo(µ-SMe)W(CO)5
(CO)4W(µ-SPh)2W(CO)4
Cp(CO)2W(µ-SMe)(µ-I)W(CO)3I
CpW(CO)(µ-SPh)2(µ-PPh2)Mo(CO)(SPh)2
CpW(CO)(µ-SPh)2(µ-PPh2)Mo(CO)3
CpW(CO)(µ-SPh)2(µ-PPh2)Mo(CO)2(PPh3)
CpW(CO)(µ-SPh)2(µ-PPh2)Mo(CO)2(PPh2H)
Cp(CO)Mo(µ-SPh)3Mo(CO)Cp
Cp(CO)Mo(µ-SCH2Ph)3Mo(CO)(SCH2Ph)2
Cp(CO)Mo(µ-SMe)2(µ-SH)Mo(CO)Cp(BF4)
(MePh)Mo(µ-SMe)4Mo(MePh)(PF6)2
CpMo(µ-SMe)4MoCp
73.2(1)
70.12(av)
69.35(av)
69.44(av)
68.68(av)
68.8(av)
68.0(av)
68.60(av)
64.33(av)
63.7(av)
2.772(2)
2.614(1)
2.603(2)
(2.4192(10) Å) and 6 (2.4226(12) Å) are shorter than
those in 1 (2.592(3) Å), 4 (2.542 (av) Å), 5 (2.517(6) Å),
and Fe3E2(CO)9 (E ) S (2.600 (av) Å),16 Se (2.650 Å
(av)),16 but close to the very strong Fe-Fe bond (2.402
Å) in (NH2)2Fe2(CO)6.17 Those bonds are even shorter
than the carbonyl-bridged iron-iron bonds in Fe4(PPh)-
(CO)11 (2.440(3) Å),15 Cp2Mo2Fe2Se2(CO)7 (2.442(2) Å),13
and Cp2Mo2Fe2Te2(CO)7 (2.433(2) (Å).14 Overall, they
are only 0.0932 Å for 3 and 0.0966 Å for 6 longer than
the formal double bond in Cp2Fe2(NO)2 (2.326(4) Å).18
The hexanuclear 4 with eight metal-metal bonds
contains 90 valence electrons, which is two electron less
to satisfy 18e for each metal atom. Thus, it is an
electronically poor cluster. This shortening may force
the Fe2(µ-S2)(CO)6 to use all four of its atoms for
coordination to the Mo atom to form two Mo-Fe bonds.
Moreover, the average bond distance of Mo-S in 4
(2.312 Å) is shorter than that in 1 (2.448(4) Å), 2 (2.489
Å), 3 (2.478 Å), 5 (2.472 Å), and 6 (2.4112 Å) and that
in Cp*(CO)2W(µ-CCPh)MoFe4(µ3-S)3((µ4-S)(CO)12 (2.415
Å),3f [Cp*Mo3(µ-O)2(µ-S)(µ3-CCPh){(Fe2(µ3-S)2(CO)6}2]
(2.401 Å),3f [Cp*WMo2(µ-O)2(µ-S)(µ3-CCPh){(Fe2(µ3-S)2-
(CO)6}2] (2.3794 Å),3f and Cp*WMo(O)2(µ-O)(µ-CCPh)-
Fe2(µ3-S)2(CO)6 (2.434 Å),3f where coordination modes
of Fe2(µ-S2)(CO)6 molecules to the Mo atom are almost
the same as that in 4. Such short Mo-S bonds in 4
indicate the existence of sulfur to molybdenum π-bond-
ing,19 which may compensate for the decrease of elec-
trons in 4.
(74.36°), 2.865(3) Å (71.07°), 2.7197(7) Å (67.98°),
2.8172(9) Å (74.74°), 2.698(3) Å (66.65°), and 2.6732(6)
Å (67.93°) for 1-6, respectively. The Mo-W bond
lengths are shorter by 0.424 Å (av) compared to the
W-Mo (3.2054(16) Å) bond length in the parent com-
pound Cp(CO)2W(µ-PPh2)Mo(CO)5.10 Table 3 compares
known molybdenum and tungsten dimers involving
single, double, triple, or quadruple bridges.20-28 It
indicates that the metal-metal bond distances in di-
nuclear compounds vary depending on the number of
bridging ligands between the metal atoms, becoming
shorter when the number of bridging ligands increases.
Therefore, the shortening of the Mo-W bond distance
in clusters 1-6 is expected since the number of bridges
in them are increased compared to that of the parent
compound Cp(CO)2W(µ-PPh2)Mo(CO)5. Furthermore,
the Mo-W lengths in doubly bridged 1 are longer than
triply bridged 2, 3, 5, and 6. Moreover, the variation of
the Mo-W lengths among them is in accord with their
average values of the angles (M-X-M, X ) S, P) in 1-6,
and those average values of the acute angles compare
well with the reported values for the structures where
(20) Shyu, S.-G.; Wu, W.-J .; Wen, Y.-S.; Peng, S.-M.; Lee, G.-H. J .
Organomet. Chem. 1995, 489, 113.
(21) Guerchais, J . E.; LeQue`re´, J . L.; Pe`tillon, F. Y. Monojlovic-Muir,
Lj.; Muir, K. W.; Sharp, D. W. A. J . Chem. Soc., Dalton Trans. 1982,
283.
(22) Lucas, C. R.; Newlands, M. J .; Gabe, E. J .; Lee, F. L. Can. J .
Chem. 1987, 65, 898.
(23) LeQue`re´, J . L.; Pe`tillon, F. Y. Guerchais, J . E.; Monojlovic-Muir,
Lj.; Muir, K. W.; Sharp, D. W. A. J . Organomet. Chem. 1983, 249, 127.
(24) Hossain, Md. M.; Lin, H.-M., Shyu, S.-G. Organometallics 2003,
22, 3262.
The Mo-W bond lengths with average values of the
acute angles (M-X-M, X ) S, P) are 2.9155(13) Å
(16) Wei, C. H.; Dahl, L. F. Inorg. Chem. 1965, 4, 493.
(17) Dahl, L. F.; Costello, W. R.; King, R. B. J . Am. Chem. Soc. 1968,
90, 5422.
(18) Claderon, J . L.; Fontana, S.; Frauendorfer, E.; Day, V. W.; Iske,
S. D. A. J . Organomet. Chem. 1974, 64, C16.
(19) Chisholm, M. H.; Cornig, J . F.; Huffman, J . C. Inorg. Chem.
1984, 23, 754.
(25) Dickson, R. S.; Fallon, G. D.; J ackson, W. R.; Polas, A. J .
Organomet. Chem. 2000, 607, 156.
(26) Schollhammer, P.; Pe`tillon, F. Y.; Pichon, R.; Poder-Guillou, S.;
Muir, K. W.; Monojlovic-Muir, Lj. Organometallics 1995, 14, 2277.
(27) Silverthorn, W. E.; Couldwell, C.; Prout, K. J . Chem. Soc.,
Chem. Commun. 1978, 1009.
(28) Connelly, N. G.; Dahl, L. F. J . Am. Chem. Soc. 1970, 92, 7470.

3948 Organometallics, Vol. 23, No. 16, 2004
Ta ble 4. Bon d Dista n ces for a F ew Su lfu r Clu ster s
Hossain et al.
cluster
Mo-Fe/W-Fe
Mo-S/W-S
Fe-S
Fe-Fe
ref
cis-Cp2Fe2Mo2S2(CO)8
trans-Cp*2Fe2Mo2S2(CO)8
(MeCp)2Fe2Mo2(CO)6S4
(MeCp)2Fe2Mo2(CO)6S3
(MeCp)2Mo2S4FeCp
Cp*2FeMo2S4(CO)2
Cp*2FeMo2S4(CO)3
Cp*2Fe2Mo2S4(CO)4
Fe2W(CO)9(PMe2Ph)S2
Fe3W(CO)11(PMe2Ph)S2
2.816(av)
2.789(av)
2.853(3)
2.331(av)
2.362(av)
2.425(av)
2.352(av)
2.406(av)
2.438(av)
2.463(av)
2.323(av)
2.424(av)
2.379(av)
2.429(2)
2.165(8)
2.213(2)
2.234(av)
2.389(av)
2.130(av)
2.153(1)
2.130(1)
2.271(av)
2.252(av)
2.192(av)
2.179(av)
2.187(av)
2.204(7)
9b
9d
30
30
30
31
31
31
11a
11a
3b
3b
32
2.803(av)
2.779(av)
2.777(av)
2.824(av)
2.813(av)
2.776(av)
2.772(av)
2.853(av)
2.815(av)
2.800(av)
2.562(av)
2.569(2)
2.572(1)
Fe2W(CO)11
S
Fe2W(CO)10(PMe2Ph)S
Cp2W2Fe(CO)7S
2.406(2)
2.358(av)
metal-metal interaction exists (Table 3).26,29 The aver-
age bond distances of Mo-Fe (2.8206 Å), W-Fe (2.7832
Å), Mo-S (2.4302 Å), W-S (2.3214 Å), Fe-S (2.2398
Å), and Fe-Fe (2.5414 Å) are also comparable with the
reported values (Table 4).3b,9b,d,11a,30-32 In general, in
these clusters the Mo-Sbr (2.4302 Å, av) and Mo-Pbr
(2.4806 Å, av) distances are longer than the W-Sbr
(2.3214 Å, av) and W-Pbr (2.4346 Å, av) distances,
respectively, and in accord with the literature
values.10,20-22 The Fe-Cbr (2.0345 Å, av) is longer than
the Fe-Ctr (1.7553 Å, av) in 1, 3, 5, and 6.
for about 20 h. The reaction mixture was filtered through
Celite to remove the insoluble material and the filtrate
evaporated to dryness. The residue was then dissolved in
dichloromethane (10 mL), and the solution was subjected to
chromatography using a silica gel column (45 cm × 3.5 cm).
Elution with a dichloromethane and hexane (1:4) mixture
collected three fractions. The first, violet fraction was a mixture
of the known compound Fe3(µ-S)2(CO)9 and starting material
Fe2(µ-S2)(CO)6. They were further separated by chromatogra-
phy with a long silica gel column (100 cm × 2.5 cm) using
hexane as an eluent. The first, orange band gave Fe2(µ-S2)-
(CO)6, and the second, violet band was Fe3(µ-S)2(CO)9. The
second fraction was a mixture of starting material Cp(CO)2-
Con clu sion s
W(µ-PPh2)Mo(CO)5 and 1. They were further separated by
silica gel column (45 cm × 2.5 cm) chromatography using a
mixture of hexane, dichlromethane, and ethyl acetate (8:1:1)
This paper describes the reactivity of Fe2(µ-S2)(CO)6
toward heterodinuclear phosphido-bridged Cp(CO)2-
as eluent. The first, violet band was Cp(CO)2W(µ-PPh2)Mo-
(CO)5 followed by a second, dirty green band, which was 1.
The third fraction was brown in color. The brown solid
obtained was further separated by silica gel column (60 cm ×
2.5 cm) chromatography with a mixture of hexane, dichloro-
methane, and ethyl acetate (8:1:1) as the eluent. Three bands
were obtained. Clusters 4, 3, and 2, were obtained from the
first, dirty green, the second, reddish brown, and the third,
brown bands, respectively. 1: Yield: 67 mg, 15%. Anal. Calcd
for C26H15O9PS2Fe2MoW: C, 32.57; H, 1.57. Found: C, 32.73;
H, 1.86. IR (CH2Cl2): ν(CO) 2047 (s), 2013 (vs), 1994 (m), 1964
W(µ-PPh2)Mo(CO)5 and Fe2(µ-S2)(CO)6 under mild con-
ditions. A new reactivity pattern is shown by Fe2(µ-S2)-
(CO)6, where it is unusually fragmented to FeS2(CO)3
and Fe(CO)3 to form 2, and also coordinated to 3 in a
unique mode. Clusters 1 and 2 are important additions
to the reaction chemistry of Fe2(µ-S2)(CO)6 with metal-
metal dinuclear complexes. The bridging phosphido
ligand may confer extra stability in 1 and 2 and
facilitate their isolation.
1
(w, sh), 1943 (w, sh), 1855 (w, br) cm-1. H NMR (CDCl3): δ
7.84-7.38 (m, 10H, C6H5), 5.19 (s, 5H, C5H5). 31P{1H} NMR
(CH2Cl2): δ 177.3 (s). 2: Yield: 27 mg, 7%. Anal. Calcd for
Exp er im en ta l Section
Gen er a l P r oced u r es. Reactions were carried out under
an atmosphere of nitrogen using standard Schlenk techniques.
All commercially available chemicals were purchased and used
as received. Solvents were dried and distilled under nitrogen
C
24H15O7PS2FeMoW: C, 34.04; H, 1.77. Found: C, 33.79; H,
1.74. IR (CH2Cl2): ν(CO) 2060 (s), 2001 (vs), 1984 (w, sh), 1938
(w, sh) 1915 (m) cm-1. 1H NMR (CDCl3): δ 7.81-7.23 (m, 10H,
C6H5), 5.67 (s, 5H, C5H5). 31P{1H} NMR (CH2Cl2): δ 115.1 (s).
3: Yield: 114 mg, 27%. Anal. Calcd for C25H15O8PS2Fe2MoW:
C, 32.22; H, 1.61. Found: C, 32.41; H, 1.63. IR (CH2Cl2): ν-
using standard methods. Compounds Cp(CO)2W(µ-PPh2)Mo-
(CO)5, Fe3(µ-S)2(CO)9, and Fe2(µ-S2)(CO)6 were prepared fol-
lowing reported procedures.1b,10 Infrared spectra were obtained
on a Perkin-Elmer 882 infrared spectrophotometer. The 1H and
31P NMR spectra were recorded on a Bruker Ac-300 spectrom-
eter. 31P NMR shifts are referenced to 85% H3PO4. Mi-
croanalyses were obtained on a Perkin-Elmer 2400 CHN
analyzer.
(CO) 2053 (s), 2007 (vs), 1954 (s), 1810 (m) cm-1 1H NMR
.
(CDCl3): δ 7.44-7.34 (m, 10H, C6H5), 5.65 (s, 5H, C5H5). 31P-
{1H} NMR (CH2Cl2): δ 25.0 (s). 4: Yield: 17 mg, 3%. Anal.
Calcd for C28H15O11PS4Fe4MoW: C 28.24, H 1.26. Found: C
28.35, H 1.43. IR (CH2Cl2): ν(CO) 2080 (s), 2049 (vs), 2018
(m), 1995 (w), 1979 (m), 1950 (m), 1758 (vw) cm-1 1H NMR
.
(CDCl3): δ 7.54-7.35 (m, 10H, C6H5), 5.64 (s, 5H, C5H5). 31P-
{1H} NMR (CH2Cl2): δ 267.6 (s). The yield is calculated on
Rea ction of Cp (CO)2W(µ-P P h 2)Mo(CO)5 w ith F e2(µ-S2)-
(CO)6. To a solid mixture of Cp(CO)2W(µ-PPh2)Mo(CO)5 (400
mg, 0.55 mmol) and Fe2(µ-S2)(CO)6 (300 mg, 0.87 mmol) was
added dichloromethane (50 mL) and the mixture kept at reflux
the basis of reacted Cp(CO)2W(µ-PPh2)Mo(CO)5 (334 mg, 0.46
mmol).
Th er m olysis of 1 in Dich lor om eth an e. A dichloromethane
solution (25 mL) of 1 (60 mg, 0.063 mmol) was kept at reflux
for 20 h, and then the reaction mixture concentrated to 5 mL.
Silica gel column (45 cm × 2.5 cm) chromatography using a
mixture of hexane and dichloromethane (3:2) as the eluent
gave 3. Yield: 45 mg, 77%.
(29) Miriam, B.; Lima, G. D.; Guerchais, J . E.; Mercier, R.; Pe`tillon,
F. Y. Organometallics 1986, 5, 1952.
(30) Cowans, B. A.; Haltiwanger, R. C.; DuBois, M. R. Organo-
metallics 1987, 6, 995.
(31) Brunner, H.; J nietz, N.; Wachter, J .; Zahn, T.; Ziegler, M. L.
Angew. Chem., Int. Ed. Engl. 1985, 24, 133.
(32) Williams, P. D.; Curtis, M. D. J . Organomet. Chem. 1988, 352,
169.
Th er m olysis of 1 in th e P r esen ce of F e2(µ-S2)(CO)6. A
dichloromethane solution (10 mL) of 1 (30 mg, 0.031 mmol)

Unusual Fragmentation of Fe2(µ-S2)(CO)6
Organometallics, Vol. 23, No. 16, 2004 3949
and Fe2(µ-S2)(CO)6 (20 mg, 0.059 mmol) was refluxed for 8 h.
The reaction mixture was concentrated to 5 mL, and three
fractions were collected by silica column (60 cm × 2.5 cm)
chromatography using hexane and dichloromethane (8:2) as
an eluent. Unreacted Fe2(µ-S2)(CO)6 (17 mg, 85% yield) was
isolated from the first, orange fraction with a trace of Fe3(µ-
S)2(CO)9 by TLC in hexane. The second, dirty green fraction
was unreacted 1 (5 mg, 17% yield). The third, reddish brown
fraction gave 3 (17 mg, 71% yield) with a trace of 2 by TLC
workup in a mixture of hexane, dichloromethane, and ethyl
acetate (8:1:1). The yield was calculated on the basis of
consumed 1.
Rea ction of 2 w ith F e2(CO)9. To a dichloromethane
solution (25 mL) of 1 (50 mg, 0.06 mmol) was added Fe2(CO)9
(110 mg, 0.3 mmol) and refluxed for 20 h. The reaction mixture
was concentrated to 5 mL, and then silica gel column (45 cm
× 2.5 cm) chromatography using a mixture of hexane, dichlo-
romethane, and ethyl acetate (8:1:1) as an eluent gave three
bands. The first unidentified band was trace in amount and
yellow in color. The second, reddish brown band was 3 (11 mg,
29% yield), and the third, brown band was unreacted 2. The
yield of 3 was calculated on the basis of reacted 2 (30 mg, 0.04
mmol).
dichloromethane and concentrated to 5 mL. The cluster 5 was
collected as a brown band on silica gel column (45 cm × 2.5
cm) chromatography using dichloromethane and hexane (1:1)
as an eluent. Yield: 16 mg, 31%. Anal. Calcd for C30H23O6-
PS2Fe2MoW: C, 37.26; H, 2.38. Found: C, 37.34; H, 2.42. IR
(CH2Cl2): ν(CO) 2006 (vs), 1978 (s) 1940 (s), 1828 (m), 1797
1
(w, sh) cm-1. H NMR (CDCl3): δ 7.68-7.23 (m, 10H, C6H5),
5.50 (s, 5H, C5H5), 5.65 (br, 2H, nbd), 4.40 (br, 2H, nbd), 3.88
(br, 2H, nbd), 1.4 (br 2H, nbd). 31P{1H} NMR (CH2Cl2): δ 27.1
(s).
Th er m olysis of 3 in Ben zen e. A benzene solution (50 mL)
of 3 (60 mg, 0.064 mmol) was refluxed for 34 h. The solution
was evaporated to dryness. The residue was then dissolved in
dichloromethane and concentrated to 5 mL. The cluster 6 was
collected as a reddish band on silica gel column (45 cm × 2.5
cm) chromatography using dichloromethane and hexane (1:1)
as an eluent. Yield: 22 mg, 37%. Anal. Calcd for C28H21O5-
PS2Fe2MoW: C, 36.36; H, 2.27. Found: C, 36. 25; H, 2.31. IR
(CH2Cl2): ν(CO) 1986 (vs), 1958 (s), 1922 (s), 1751 (m) cm-1
.
1H NMR (CDCl3): δ 7.37-7.29 (m, 10H, C6H5), 5.40 (s, 5H,
C5H5), 5.20 (s, 6H, C6H6). 31P{1H} NMR (CH2Cl2): δ -6.2 (s).
Cr yst a l St r u ct u r e Det er m in a t ion of Clu st er s 1-6.
Individual solutions of compounds 1-5 in dichloromethane
were layered by hexane first. The single crystals of 1-5 for
X-ray diffraction analyses were grown by slow evaporation of
these mixtures at 0 °C, respectively. A single crystal of 6 was
obtained similarly by slow evaporation of its dichloromethane
solution layered by toluene at 0 °C. For each of the clusters
1-6, a selected single crystal was mounted on a glass fiber
for data collection by using Mo KR radiation on an Enraf
Nonius CAD4 diffractometer at room temperature. Table 1
gives further details. Unit cell parameters were refined from
25 reflections with the 2θ range 14.52-35.92°. Three standard
reflections were monitored every hour throughout the data
collection. The variation was within 6%. Lorentz and polariza-
tion corrections were applied. A semiempirical absorption
correction was applied based on azimuthal scans of three
reflections. All structures were solved by direct methods. For
all hydrogen atoms, the atomic and isotropic thermal param-
eters were fixed. Structure refinement was performed using
the Wingx33 program on a PC.
Rea ction of Cp (CO)2W(µ-P P h 2)Mo(CO)5 w ith F e3(µ-S)2-
(CO)9. A solid mixture of Cp(CO)2W(µ-PPh2)Mo(CO)5 (100 mg,
0.14 mmol) and Fe3(µ-S)2(CO)9 (100 mg, 0.21 mmol) was
dissolved in 50 mL of dichloromethane. The mixture was
refluxed for 20 h. The reaction mixture was concentrated to 5
mL, which was then subjected to chromatograpy using a silica
gel column (45 cm × 2.5 cm) with a mixture of hexane and
dichloromethane (4:1) as the eluent. Compounds Fe3(µ-S)2(CO)9
(93 mg, 93% yield) and Cp(CO)2W(µ-PPh2)Mo(CO)5 (97 mg,
97% yield) were obtained from the first, violet and the second,
violet bands, respectively. Both complexes were identified by
comparing their IR and 31P{1H} NMR spectra with the
literature data.1b,10
Reflu x of Fe2(µ-S2)(CO)6 in Dich lor om eth an e. A dichloro-
methane solution (25 mL) of Fe2(µ-S2)(CO)6 (100 mg, 0.29
mmol) was kept at reflux for 20 h. Silica gel column (45 cm ×
2.5 cm) chromatography of the concentrated reaction mixture
(5 mL) using hexane as an eluent recovered 95 mg (95% yield)
of Fe2(µ-S2)(CO)6.
Rea ction of 3 w ith F e2(µ-S2)(CO)6. To a mixture of 3 (80
mg, 0.09 mmol) and Fe2(µ-S2)(CO)6 (45 mg, 0.13 mmol) was
added 50 mL of dichloromethane and refluxed for 20 h. The
reaction mixture was concentrated to 5 mL, and then chro-
matographic workup (silica gel column) using hexane and
dichloromethane (3:1) as an eluent afforded the first, orange
band, Fe2(µ-S2)(CO)6 (42 mg, 93% yield), and the second,
reddish brown band, 3 (78 mg, 97% yield), respectively.
Rea ction of 3 w ith Nor bor n a d ien e. To a benzene solu-
tion (50 mL) of 3 (50 mg, 0.053 mmol) was added nbd (25 mg,
0.27 mmol) and then refluxed for 30 h. The reaction mixture
was evaporated to dryness. The residue was then dissolved in
Ack n ow led gm en t. We acknowledge the National
Science Council of the Republic of China and Academia
Sinica for financial support of this work.
Su p p or tin g In for m a tion Ava ila ble: Tables of atomic
coordinates, isotropic and anisotropic displacement param-
eters, and all bond distances and angles, and experimental
details of the X-ray studies for 1-6. This material is available
free of charge via the Internet at http://pubs.acs.org.
OM049821T
(33) Farrugia, L. J . J . Appl. Crystallogr. 1999, 32, 837.