Reactions of the triosmium-antimony cluster Os3(μ-SbPh2)(μ-H)(μ3,η2 -C6H4)(CO)9 with alkynes: C-C bond coupling to a cluster-bound phenylene and catalytic alkyne cyclotrimerization

Article abstract of DOI:10.1021/om010911x

The reaction of the osmium - antimony cluster Os₃(μ-SbPh₂)(μ-H)(μ₃, η²-C₆H₄)(CO)₉ (1) with the terminal alkynes PhC≡CH and ^tBuC≡CH was presented. The reaction led to products involving C-C bond coupling with the phenylene ligand on the cluster Os₃(μ-SbPh₂)(μ, η²- HC=C(H)Ph)(μ- η⁴-C₆H₄C-(H)CPh)(CO)₇. It was found that cluster 1 was an effective catalyst for the cyclotrimerization of diphenylacetylene to hexaphenylbenzene.

Full text of DOI:10.1021/om010911x

Organometallics 2002, 21, 1221-1226
1221
Rea ction s of th e Tr iosm iu m -An tim on y Clu ster
Os3(µ-SbP h 2)(µ-H)(µ3,η2-C6H4)(CO)9 w ith Alk yn es: C-C
Bon d Cou p lin g to a Clu ster -Bou n d P h en ylen e a n d
Ca ta lytic Alk yn e Cyclotr im er iza tion
Mingli Deng and Weng Kee Leong*
Department of Chemistry, National University of Singapore, Kent Ridge, Singapore 119260
Received October 22, 2001
The reaction of the osmium-antimony cluster Os3(µ-SbPh2)(µ-H)(µ3,η2-C6H4)(CO)9, 1, with
t
the terminal alkynes PhCtCH and BuCtCH led to products involving C-C bond coupling
with the phenylene ligand on the cluster, viz., Os3(µ-SbPh2)(µ,η2-HCdC(H)Ph)(µ-η4-C6H4C-
(H)CPh)(CO)7, 2, and Os5(µ4-Sb)(µ-SbPh2)(µ-H)(µ3,η3-C6H4)(µ,η2-PhCdC(H)But)(CO)14, 4.
Cluster 1 was also found to be an effective catalyst for the cyclotrimerization of diphen-
ylacetylene to hexaphenylbenzene.
In tr od u ction
Resu lts a n d Discu ssion
One of the reasons for the study of organometallic
clusters is their potential as catalysts because of the
possibility of synergism among the metal centers.1 This
has resulted in a relatively vast amount of work on the
reaction of clusters with organic molecules. In particu-
lar, alkynes have generated a lot of interest, as they
have been shown to be very reactive with organometallic
clusters and they offer a variety of bonding interactions
with the metal centers.2,3 One of the goals in our studies
on organometallic clusters has been to investigate the
interaction of cluster-bound ligands with other sub-
strates. A particular cluster-bound ligand of interest to
us is phenylene (or benzyne). This ligand has been
demonstrated to have interesting properties and reac-
tivities. Thus it undergoes exchange of the aryne
hydrogens with metal hydrides,4 can be acylated or
alkylated,5 and can undergo CO insertion reactions.6 We
were interested in examining the possibility of C-C
bond coupling reactions involving the phenylene ligand
on the cluster Os3(µ-SbPh2)(µ-H)(µ3,η2-C6H4)(CO)9, 1.7
In this paper, we wish to report our investigations on
the reactions of 1 with alkynes.
The reaction of 1 with PhCCH at 70 °C over 15 h
afforded an orange solution from which the major
product Os3(CO)7(µ-SbPh2)(µ,η2:η4-PhCdC(H)C6H4)(µ,η1:
η2-CHdC(H)Ph), 2, was isolated in 65% yield. The
molecular structure of 2 is shown in Figure 1, together
with selected bond parameters. The molecular structure
of 2 reveals that coupling of two alkyne molecules with
1 has occurred, giving rise to two discrete hydrocarbyl
ligands. A salient structural feature is the direct coup-
ling of the C6H4 phenylene ring with one of the phenyl-
acetylene molecules. The resulting ligand is coordinated
in a µ,η2:η4 fashion to the Os(2)-Os(3) edge, via an η2
mode to Os(2) and an η4 mode to Os(3). The second
hydrocarbyl fragment is derived from a second phenyl-
acetylene molecule which has inserted into the os-
mium-hydride linkage to give a three-electron-donating
vinyl µ,η1:η2-CHdC(H)Ph unit; this bonding mode has
been encountered, for example, in Os3(µ-H)(CO)10(µ3,η3-
CHCPhCH) and Os3(CO)8(µ3,η3-CHCPhCH)(µ,η2-Ph-
CCH2).8,9
1
An assignment of the nonphenyl H NMR signals of
complex 2 has been made with the aid of two-dimen-
sional homonuclear correlation spectroscopy (COSY)
and rotation frame Overhauser enhancement spectros-
copy (ROESY). The singlet at δ 7.95 is assigned to the
proton Hc (Figure 2); it exhibits the characteristic low-
field resonance shift of coordinated alkenyls.3 The
resonances at δ 6.27 and 6.01 are assigned to the two
vinyl protons, Ha and Hb, respectively; Hb should exhibit
a lower field resonance shift because of deshielding from
the neighboring phenyl ring. The resonances from the
C6H4 moiety are assigned on the basis of their multi-
plicities and the observation of strong NOE between Hc
and Hd, and Ha and Hg, respectively; these are consis-
(1) Adams, R. D., Cotton, F. A., Eds. In Catalysis by Di- and
Polynuclear Metal Cluster Complexes; Wiley-VCH: New York, 1998.
(2) See for example: (a) Wong, W. Y.; Ting, F. L.; Lam, W. L. Eur.
J . Inorg. Chem. 2001, 623. (b) Charmant, J . P. H.; Davies, G.; King,
P. J .; Wigginton, J . R.; Sappa, E. Organometallics 2000, 19, 2330. (c)
Ang, H. G.; Ang, S. G.; Du, S. W. J . Chem. Soc., Dalton Trans. 1999,
2963. (d) Ferrand, V.; Suss-Fink, G.; Neels, A.; Stoeckli-Evans, H. Eur.
J . Inorg. Chem. 1999, 853. (e) Adams, C. J .; Bruce, M. I.; Skelton, B.
W.; White, A. H. J . Chem. Soc., Dalton Trans. 1999, 1283. (f) Ferrand,
V.; Suss-Fink, G.; Neels, A.; Stoeckli-Evans, H. J . Chem. Soc., Dalton
Trans. 1998, 3825. (g) County, G. R.; Dickson, R. S; Fallon, G. D. J .
Organomet. Chem. 1998, 565, 11. (h) Went, M. J . Adv. Organomet.
Chem. 1997, 41, 69.
(3) Sappa, E.; Tiripicchio, A.; Braunstein, P. Chem. Rev. 2001, 11,
2280.
(4) Kneuper, H. J .; Shapley, J . R. Organometallics 1987, 6, 2455,
1987.
(5) Chen, H.; J ohnson, B. F. G.; Lewis, J . Organometallics 1989, 8,
2965.
(6) (a) Charmant, J . P. H.; Dickson, H. A. A.; Grist, N. J .; Keister,
J . B.; Knox, S. A. R.; Morton, D. A. V.; Orpen, A. G.; Vinas, J . M. J .
Chem. Soc., Chem. Commun. 1991, 1393. (b) Charmant, J . P. H.;
Dickson, H. A. A.; Grist, N. J .; Knox, S. A. R.; Orpen, A. G.; Saynor,
K.; Vinas, J . M. J . Organomet. Chem. 1998, 565, 141.
(7) Leong, W. K.; Chen, G. Organometallics 2001, 20, 2280.
(8) Goudsmit, R. J .; J ohnson, B. F. G.; Raithby, P. R.; Clegg, W. Acta
Crystallogr., Sect B 1982, 38, 2689.
(9) Wong, W. Y.; Chan, S.; Wong, W. T. J . Chem. Soc., Dalton Trans.
1995, 1497.
10.1021/om010911x CCC: $22.00 © 2002 American Chemical Society
Publication on Web 02/20/2002

1222 Organometallics, Vol. 21, No. 6, 2002
Deng and Leong
F igu r e 1. ORTEP plot of 2 (50% thermal ellipsoids;
aromatic hydrogens omitted): Os(1)Os(2) 2.9863(4) Å; Os-
(2)Os(3) 2.8569(4) Å; Os(1)Sb(4) 2.6408(5) Å; Os(3)Sb(4)
2.5902(5) Å; Os(1)C(23) 2.107(7) Å; Os(2)C(23) 2.267(6) Å;
Os(2)C(24) 2.377(6) Å; Os(2)C(121) 2.208(6) Å; Os(2)C(130)
2.120(7) Å; Os(3)C(120) 2.252(7) Å; Os(3)C(121) 2.294(6)
Å; Os(3)C(122) 2.366(7) Å; Os(3)C(130) 2.258(7) Å; C(23)C-
(24) 1.395(9) Å; C(120)C(122) 1.434(10) Å; C(120)C(130)
1.409(9) Å; Os(3)Os(2)Os(1) 83.780(10)°; Os(3)Sb(4)Os(1)
96.498(17)°; Sb(4)Os(1)Os(2) 82.360(13)°; Sb(4)Os(3)Os(2)
85.830(13)°.
F igu r e 3. ORTEP plot of 3 (50% thermal ellipsoids;
hydrogens omitted): Os(1)Os(2) 2.8945(3) Å; Os(1)Sb(3)
2.6598(4) Å; Os(1)C(1) 2.283(4) Å; Os(1)C(2) 2.422(6) Å; Os-
(2)C(1) 1.967(7) Å; C(1)C(2) 1.339(10) Å; C(2)C(3) 1.391-
(12) Å; Os(1)Os(2)Os(1′) 77.835(10)°; Sb(3)Os(1)Os(2) 78.511-
(10)°.
F igu r e 4. ORTEP plot of 4 (50% thermal ellipsoids;
organic hydrogens omitted): Os(1)Os(2) 2.9393(4) Å; Os-
(2)Os(3) 2.9371(4) Å; Os(4)Os(5) 2.8688(4) Å; Os(1)Sb(6)
2.7805(5) Å; Os(2)Sb(6) 2.5812(5) Å; Os(4)Sb(6) 2.6726(5)
Å; Os(5)Sb(6) 2.6390(5) Å; Os(1)Sb(7) 2.6846(5) Å; Os(3)-
Sb(7) 2.6527(5) Å; C(1)C(2) 1.421(9) Å; C(2)C(3) 1.561(10)
Å; Os(3)Os(2)Os(1) 88.039(10)°; Sb(7)Os(1)Os(2) 84.541-
(13)°; Sb(6)Os(1)Os(2) 53.564(11)°; Sb(6)Os(2)Os(1) 60.069-
(13)°; Sb(7)Os(3)Os(2) 85.147(13)°; Sb(6)Os(4)Os(5) 56.746-
(12)°; C(1)C(2)C(3) 131.1(6)°.
F igu r e 2. 1H NMR assignment for non-phenyl hydrogens
of 2.
tent with the distances (Hc‚‚‚Hd ) 2.65 Å and Ha‚‚‚Hg
) 2.17 Å) observed in the X-ray crystal structure.
t
The reaction of 1 with BuCCH at 80 °C afforded two
orange clusters, Os3(µ-SbPh2)[µ3,η2-CtCBut](CO)9, 3,
and minor amounts of the novel cluster Os5(µ4-Sb)(µ-
SbPh2)(µ-H)(µ,η1:η2-PhCdC(H)But)(µ,η3-C6H4)(CO)14, 4.
Both were characterized completely, including by single-
crystal X-ray crystallography. The ORTEP diagrams
showing the molecular structures of 3 and 4, together
with selected bond distances and bond angles, are given
below (Figures 3 and 4, respectively). In 3, the C6H4 ring
“activated” end of the range (1.27-1.32 Å) that has been
observed for a number of such group 8 alkyne clusters.3
The metal core of 4 consists of a closed triosmium unit
linked by a µ4-Sb atom to a diosmium unit. The 1H NMR
spectrum shows a singlet resonance at -14.25 ppm,
which is indicative of a bridging metal hydride. Al-
though not located directly in the electron density dif-
ference map, potential energy calculations suggest that
it bridges the Os(2)-Os(3) edge.12 As may be expected,
the C(1)-C(2) bond length (1.421(9) Å) is between the
ranges of carbon-carbon sp2-sp2 double and single
bonds (1.32 and 1.48 Å, respectively).11
t
of 1 has been replaced by a BuCC group. The acetylenic
ligand is considered to be coordinated to the metallic
cluster as a five-electron donor via a µ3,η1:η2:η2-bonding
mode. Such a bonding mode has been observed in
similar complexes such as Os3(µ-H)(µ3,η2-C2But)(CO)9.10
The C(1)-C(2) acetylenic bond length (1.339(10) Å) is
between that for an sp-sp double and single bond (1.28
and 1.38 Å, respectively)11 and lies beyond the more
(11) Smith, M. B.; March, J . March’s Advanced Organic Chemistry,
5th ed.; Wiley: New York, 2001; p 20.
(10) Deeming, A. J .; Hasso, S.; Underhill, M. J . Chem. Soc., Dalton
Trans. 1975, 1614.
(12) Orpen, A. G. XHYDEX: A Program for Locating Hydrides in
Metal Complexes; School of Chemistry, University of Bristol, UK, 1997.

Reactions of a Triosmium-Antimony Cluster with Alkynes
Organometallics, Vol. 21, No. 6, 2002 1223
Sch em e 1. Rea ction of 1 w ith P h CCP h a
a
Percent yields for clusters calculated with respect to amount of 1 used.
Ta ble 1. Cyclotr im er iza tion Rea ction s of P h CCP h
run no.
cluster
amt of PhCCPh
temp (°C)
yield of 10
TONa
1
2
3
4
5
1 (8.2 mg, 7.0 µmol)
1 (13.0 mg, 11.0 µmol)
5 (12.7 mg, 11.0 µmol)
1 (11.8 mg, 10.0 µmol)
5 (8.2 mg, 9.0 µmol)
85.2 mg, 478 µmol
61.8 mg, 347 µmol
62.6 mg, 351 µmol
44.0 mg, 247 µmol
52.8 mg, 296 µmol
70
100
100
150
150
5.9 mg, 6.9%
8.6 mg, 14%
3.2 mg, 5.1%
38.5 mg, 88%
7.0 mg, 13%
1.6
1.5
0.5
7.2
1.5
a
TON (catalytic turnover number) ) moles of product/moles of catalyst.
Cluster 4 is structurally very similar to Os5(µ4-Sb)-
(µ-SbPh2)(µ-H)2(µ3,η2-C6H4)(µ,η2-C6H4)(CO)14, 7, which
has been observed in the reaction of 1 with alkenes and
dienes13 and with diphenylacetylene (see later). The
main structural difference is the replacement of the
bridging phenylene and hydride in 7 by the µ,η1:η2
vinylic group in 4, which has resulted in a shorter
Os(4)-Os(5) distance in 4 (2.8688(4) Å) compared to that
in 7 (3.0305(5) Å). Given the structural similarities
between 4 and 7, it is conceivable that 7 may have been
the precursor to 4. This would have required deortho-
metalation of the phenylene ring on the diosmium unit
as well as insertion of the alkyne into the resultant
continued to be of interest. Although phenylene-contain-
ing clusters have been recently reported to be efficient
catalysts for alkyne hydrogenation,14 this is the first
instance that we are aware of in which this class of
clusters catalyzes alkyne cyclotrimerization. A large
variety of organometallic compounds have been reported
to catalyze this reaction,15 but relatively few cluster
catalysts are known and even then it is often not clear
whether the catalytically active species is indeed a
cluster.16 Among cluster compounds of the group 8
elements, Fe3(CO)12 has been found to be a good catalyst
for the cyclotrimerization of PhCCPh to Ph6C6.16a It has
also been shown that Os3(CO)12, 5, catalyzes the same
t
Os-Ph bond. However, on heating 7 and BuCCH at
(13) Deng, M.; Leong, W. K. J . Chem. Soc., Dalton Trans, in
press.
(14) (a) Castiglioni, M.; Deabate, S.; Giordano, R.; King, P. J .; Knox,
S. A. R.; Sappa, E. J . Organomet. Chem. 1998, 571, 251. (b) Allasia,
C.; Castiglioni, M.; Giordano, R.; Sappa, E. J . Cluster Sci. 2000, 11,
493.
100 °C, monitoring by IR spectroscopy showed that
there was no reaction even after 15 h. On the other
hand, heating 4 alone at 100 °C led to decomposition to
some unidentified products.
(15) (a) Mori, N.; Ikeda, S.; Odashima, K. J . Chem. Soc., Chem.
Commun. 2001, 181. (b) Sigman, M. S.; Fatland, A. W.; Eaton, B. E.
J . Am. Chem. Soc. 1998, 120, 5130. (c) Sato, Y.; Ohashi, K.; Mori, M.
Tetrahedron Lett. 1999, 40, 5231. (d) Larock, R. C.; Tian, Q. J . Org.
Chem. 1998, 63, 2002. (e) Nishida, M.; Shiga, H.; Mori, M. J . Org.
Chem. 1998, 63, 8606. (f) Gevorgyan, V.; Takeda, A.; Yamamoto, Y. J .
Am. Chem. Soc. 1997, 119, 11313. (g) Taber, D. F.; Rahimizadeh, M.
Tetrahedron Lett. 1994, 35, 9139. (h) Sato, Y.; Nishimata, T.; Mori,
M. J . Org. Chem. 1994, 59, 6133. (i) Hopff, H.; Gati, A. Helv. Chim.
Acta 1965, 48, 509. (j) Hopff, H. Chimia 1964, 18, 140. (k) Arnett, E.
M.; Bollinger, J . M. J . Am. Chem. Soc. 1964, 86, 4729. (l) Viehe, H. G.;
Mere´nyi, R.; Oth, J . F. M.; Valange, P. Angew. Chem., Int. Ed. Engl.
1964, 3, 746. (m) Viehe, H. G.; Mere´nyi, R.; Oth, J . F. M.; Senders, J .
R.; Valange, P. Angew. Chem., Int. Ed. Engl. 1964, 3, 755.
(16) (a) Hu¨bel, W.; Hoogzand, C. Chem. Ber. 1960, 93, 103. (b) Yin,
C. C.; Deeming, A. J . J . Organomet. Chem. 1978, 144, 351. (c) Ren, C.
Y.; Cheng, W. C.; Chan, W. C.; Yeung, C. H.; Lau, C. P. J . Mol. Catal.
1990, 59, L1. (d) Baidossi, W.; Goren, N.; Blum, J .; Schumann, H.;
Hemling, H. J . Mol. Catal. 1993, 85, 153.
The reaction of 1 with an equimolar amount of
PhCCPh at 90 °C in a Carius tube afforded a dark red
solution that, upon separation by TLC, afforded (besides
unconsumed 1) six cluster products and hexaphenyl-
benzene, 10 (Scheme 1). All the cluster products have
been identified, except for the unknown red compound
that eluted as band 4. This was separable from 6 only
after repeated TLC with hexane as eluant. The mass
spectrum of this product showed a cluster of peaks at
m/z 1864; on standing for several days, a new cluster of
peaks centered at m/z 1330 corresponding to 6 appeared.
Thus band 4 seemed to decompose slowly to 6.
The cyclotrimerization of alkynes to form highly
substituted benzenes is an intriguing reaction that has

1224 Organometallics, Vol. 21, No. 6, 2002
Deng and Leong
µ-η2-PhCdC(H)Ph ligand (a σ,π-vinyl system) and for-
mation of an Os-Os bond. The C(1)-C(2) length for the
µ-η2-PhCdC(H)Ph ligand (1.443(10) Å) is closer to that
of an sp2-sp2 single bond length and suggests that the
C(1)-C(2) bond has a much reduced multiple-bond
character. The most significant feature is the very short
Os(2)-Os(3) bond, which, at 2.6401(4) Å, is the shortest
Os-Os bond length observed to date for a triosmium
cluster. This bond shortening is similar to that in
Os3(µ,η2-CPhCHPh)(µ,η3-C3Ph3)(CO)8, in which the
Os-Os bridged by a µ,η2-PhCdC(H)Ph ligand is also
shortened to 2.694(2) Å.20 These distances are signifi-
cantly below the range of Os-Os distances (2.814-2.834
Å) found for a number of other triosmium clusters in
which an Os-Os edge is bridged by an µ-η2-alkenyl
ligand and a hydride.8,21
That the reaction of 1 with diphenylacetylene appar-
ently did not afford C-C coupled products involving the
cluster-bound phenylene is consistent with the observa-
tion made earlier on the related cluster Os3(µ-H)2(µ3,η2-
C6H4)(CO)9.22 The contrasting behavior with the termi-
nal alkynes is interesting and suggests that the acetylenic
hydrogen may have a role in effecting C-C coupling
with the phenylene; work is currently underway to
determine what this role is.
F igu r e 5. ORTEP plot of 6 (50% thermal ellipsoids;
aromatic hydrogens omitted): Os(1)-Os(2) 2.9983(4) Å; Os-
(1)Os(3) 2.8873(4) Å; Os(2)Os(3) 2.6401(4) Å; Os(1)Sb(4)
2.6957(5) Å; Os(2)Sb(4) 2.5855(5) Å; Os(1)C(10) 2.150(7) Å;
Os(2)C(1) 2.149(6) Å; Os(2)C(20) 2.165(7) Å; Os(3)C(1)
2.137(6) Å; Os(3)C(2) 2.240(7) Å; Os(3)C(10) 2.269(6) Å; Os-
(3)C(20) 2.263(7) Å; C(1)C(2) 1.443(10) Å; C(10)C(20) 1.420-
(9) Å; Os(1)Os(3)Os(2) 65.521(10)°; Os(3)Os(2)Os(1) 61.216-
(9)°; Os(3)Os(1)Os(2) 53.263(9)°; Os(2)Sb(4)Os(1) 69.147(14)°.
reaction,17 and much of the reaction sequence has been
worked out.18 In contrast, Ru3(CO)9(NCCH3)3 reacted
with disubstituted alkynes to yield Ru3(CO)9(µ3-η2:η2:
η2-C6R3R′3) complexes, which decomposed to yield the
free substituted benzene on heating.19
In conclusion, we have found that the osmium-anti-
mony cluster 1 is an effective catalyst for the cyclotri-
merization of diphenylacetylene to hexaphenylbenzene.
In contrast, its reactions with terminal alkynes led to
cluster products with C-C bond formation involving the
phenylene ligand.
Although 5 has been shown to be an effective agent
for the cyclotrimerization of diphenylacetylene, no data
on the catalytic efficiency was reported. We have
therefore investigated this reaction at different temper-
atures and substrate:catalyst ratio, for both 1 and 5
(Table 1). Under similar conditions, 1 is a more efficient
catalyst than 5 for the cyclotrimerization. We have also
found that 6 reacted with PhCCPh to afford 10; it may
therefore be an intermediate in the catalytic cycle. This
is of significance, as it would support the notion that
the active catalyst is a cluster species. In contrast, 7
failed to react with PhCCPh under similar conditions,
and the reaction with 8 led to other products but no 10.
Both 7 and 8 have earlier been observed as products
from the reactions of 1 with a number of alkenes and
dienes, suggesting that they are the result of ligand-
assisted cluster condensation.13 Cluster 9 has been
shown in our earlier work to result from the thermolytic
decomposition of 1 itself;7 we have found that it does
react with PhCCPh to afford 10, albeit in very low yield
(∼1% after 14 1/2 h at 100 °C), thus suggesting that it
is probably not directly involved in the catalytic cycle.
The molecular structure of 6 and selected bond
parameters are shown in Figure 5. It may be formally
derived from 1 by the replacement of two terminal
carbonyls and a hydride by the three-electron donor
Exp er im en ta l Section
Gen er a l P r oced u r es. All reactions and manipulations
were performed under a nitrogen atmosphere by using stan-
dard Schlenk techniques. Solvents were purified, dried, dis-
tilled, and kept under nitrogen prior to use. NMR spectra were
recorded on a Bruker ACF 300 MHz NMR spectrometer; 2D
experiments were carried out on a Bruker ACF500 MHz NMR
spectrometer. EI-MS spectra were acquired on a Micromass
VG7035 mass spectrometer. Elemental analyses were carried
out by the microanalytical laboratory at the National Univer-
sity of Singapore. Cluster 1 was prepared by the literature
method;7 all other reagents were from commercial sources and
used as supplied.
Rea ction of 1 w ith P h CCH. To a Carius tube containing
1 (20.8 mg, 0.018 mmol) and dichloromethane (10 mL) was
added PhCCH (10.2 mg, 0.100 mmol). After stirring at 70 °C
for 15 h, the color of the solution changed from yellow to
orange. Solvent was removed on the vacuum line, and the
residue so obtained was redissolved in the minimum volume
of dichloromethane and chromatographed on silica TLC plates.
Elution with hexane gave unreacted 1 (5.3 mg) and yellow
crystals of Os3(µ-SbPh2)(µ,η2-HCdC(H)Ph)(µ-η4-C6H4C(H)CPh)-
(CO)7, 2. Yield ) 11.3 mg, 48%. IR (hexane) ν(CO): 2062s,
2023m, 2014vs, 1993w, 1977m, 1956m cm-1. 1H NMR: δ 7.95
(s, 1H), 7.69 (d, 1H), 7.1-7.5 (m, Ph), 7.12 (dd, 3J HH ) 9.0 Hz),
(17) (a) Vaglio, G. A.; Gambino, O.; Ferrari, R. P.; Cetini, G. Inorg.
Chim. Acta 1973, 7, 193. (b) Valle, M.; Cetini, G.; Gambino, O.; Sappa,
E. Atti Accad. Sci. Torino 1969, 105, 913.
(19) Edwards, A. J .; Leadbeater, N. E.; Lewis, J .; Raithby, P. R. J .
Chem. Soc., Dalton Trans. 1995, 3785.
(20) Churchill, M. R.; Ziler, J . W.; Shapley, J . R.; Yeh, W. Y. J .
Organomet. Chem. 1988, 353, 103.
(21) (a) Clauss, A. D.; Tachikawa, M.; Shapley, J . R.; Pierpont, C.
G. Inorg. Chem. 1981, 20, 1528. (b) Goudsmit, R. J .; J ohnson, B. F.
G.; Raithby, P. R.; Clegg, W. Acta Crystallogr., Sect. B 1982, 38, 2689.
(c) Sappa, E.; Tiripicchio, A.; Manotti Lanfredi, A. M. J . Chem. Soc.,
Chem. Commun. 1986, 318.
(22) Chen, H.; J ohnson, B. F. G.; Lewis, J .; Raithby, P. R. J .
Organomet. Chem. 1989, 376, C7.
(18) (a) Gambino, O.; Vaglio, G. A.; Ferrari, R. P.; Cetini, G. J .
Organomet. Chem. 1971, 30, 381. (b) Ferrari, R. P.; Vaglio, G. A.;
Gambino, O.; Valle, M.; Cetini, G. J . Chem. Soc., Dalton Trans. 1972,
1998. (c) Ferraris, G.; Gervasio, G. J . Chem. Soc., Dalton Trans. 1972,
1057. (d) Ferraris, G.; Gervasio, G. J . Chem. Soc., Dalton Trans. 1974,
1813. (e) Gambino, O.; Ferrari, R. P.; Chinone, M.; Vaglio, G. A. Inorg.
Chim. Acta 1975, 12, 155. (d) Tachikawa, M.; Shapley, J . R.; Pierpont,
C. G. J . Am. Chem. Soc. 1975, 97, 7172.

Reactions of a Triosmium-Antimony Cluster with Alkynes
Organometallics, Vol. 21, No. 6, 2002 1225
Ta ble 2. Cr ysta l Da ta for 2, 3, 4, a n d 6
2
3
4
6
empirical formula
fw
temp, K
C
41H27O7Os3Sb‚1/2CH2Cl2
C27H19O9Os3Sb
1179.77
223(2)
C44H30O14Os5Sb2
1977.18
193(2)
C39H25O7Os3Sb‚1/4C6H14
1319.48
223(2)
1366.44
223(2)
cryst syst
space group
a, Å
b, Å
c, Å
triclinic
P1h
orthorhombic
Pnma
20.1830(4)
13.1745(3)
11.1624(2)
90
monoclinic
C2/c
33.7108(12)
13.9251(5)
21.0185(7)
90
95.791(1)
90
9816.3(6)
8
triclinic
P1h
9.2354(1)
10.0936(2)
22.8557(4)
101.084(1)
97.728(1)
97.503(1)
2044.86(6)
2
9.3913(1)
13.5210(1)
16.7683(2)
82.149(1)
85.300(1)
72.680(1)
2011.72(4)
2
R, deg
â, deg
90
90
γ, deg
volume, Å3
Z
2968.09(10)
4
density (calcd),
2.219
2.640
2.676
2.178
Mg/m3
abs coeff, mm-1
F(000)
10.056
1258
13.751
2128
14.035
7104
10.154
1213
cryst size, mm3
θ range for data
collection, deg
index ranges
0.28 × 0.07 × 0.05
0.26 × 0.20 × 0.07
0.20 × 0.10 × 0.08
0.30 × 0.20 × 0.10
2.08 to 29.32
2.02 to 31.67
2.19 to 31.03
2.12 to 29.08
-12 e h e 12,
-13 e k e 13,
0 e l e 30
0 e h e 28,
0 e k e 18,
0 e l e 16
-47 e h e 47,
0 e k e 19,
0 e l e 29
-12 e h e 12,
-17 e k e 18,
0 e l e 22
no. of reflns collected
no. of ind reflns
max. and min.
transmn
17 316
27 535
86 839
15 383
9695 [R(int) ) 0.0346]
0.603955 and
0.337559
4904 [R(int) ) 0.0742]
0.382469 and
0.129349
15176 [R(int) ) 0.0442]
0.381768 and
0.247246
9442 [R(int) ) 0.0332]
0.263869 and
0.134745
no. of data/restraints/
params
9695/6/513
4904/0/206
15176/0/590
9442/0/463
goodness-of-fit on F2
final R indices
[I>2σ(I)]
1.056
1.001
0.790
1.048
R1 ) 0.0369,
wR2 ) 0.0735
R1 ) 0.0556,
wR2 ) 0.0808
1.304 and -1.202
R1 ) 0.0334,
wR2 ) 0.0710
R1 ) 0.0437,
wR2 ) 0.0735
1.735 and -1.778
R1 ) 0.0367,
wR2 ) 0.0634
R1 ) 0.0658,
wR2 ) 0.0685
2.749 and -1.285
R1 ) 0.0376,
wR2 ) 0.0893
R1 ) 0.0524,
wR2 ) 0.0967
1.593 and -2.369
R indices (all data)
largest diff peak and
hole, e Å-3
3
6.27 (d, 1H), 6.13 (d, 1H), 6.01 (d, 1H, J HH ) 14.0 Hz), 5.88
Band 3 gave orange crystals of Os3(µ-SbPh2)(µ3,η2-C6H4)(µ-
PhCdC(H)Ph)(CO)7, 6. Yield ) 11.2 mg, 16%. IR (hexane)
3
3
(dd, 1H, J HH ) 8.2 Hz, J HH ) 9.0 Hz). Anal. Calcd for
41H27O7Os3Sb: C, 37.19; H, 2.06. Found: C, 37.06; H, 2.21.
C
ν(CO): 2078w, 2054m, 2020sh, 1985m, 1963m cm-1 1H
.
Presence of dichloromethane in the crystalline samples used
NMR: δ 8.4-6.5 (m, aromatic), 6.44 (s, CH). Anal. Calcd for
1
for the X-ray diffraction study was confirmed by H NMR.
C39H25O7Os3Sb‚1/2C6H14: C, 37.61; H, 2.40. Found: C, 37.31;
t
Rea ction of 1 w ith Bu CCH. To a Carius tube containing
H, 2.58. Presence of the hexane solvent of crystallization was
1
1 (56.2 mg, 0.048 mmol) and dichloromethane (10 mL) was
confirmed by H NMR spectroscopy.
t
added BuCCH (4.1 mg, 0.05 mmol). After stirring at 80 °C
Band 4 was a red unstable product. Yield ) 12.5 mg. IR
(hexane) ν(CO): 2065w, 2053m, 2022sh, 2009sh, 1992m,
1963m cm-1. Bands 5, 6, and 7 were identified by the IR and
1H NMR spectra as the previously reported clusters Os5(µ4-
Sb)(µ-SbPh2)(µ-H)2(µ3,η2-C6H4)(µ,η2-C6H4)(CO)14, 7 (10.8 mg,
22%), Os5(µ4-Sb)(µ-SbPh2)(µ-H)(µ3,η6-C6H4)(C6H5)(CO)14, 8 (2.0
mg, 4%), and Os6(µ4-Sb)(µ-SbPh2)(µ-H)(µ3,η2-C6H4)2(C6H5)-
(CO)16, 9 (3.6 mg, 6%), respectively.
Band 8 gave colorless crystals of C6Ph6, 10. Yield ) 2.6
mg, 73%. 1H NMR: δ 6.9-6.8 (m, Ph). MS (EI, 70 eV): m/z
534.1 (M+), 457.2 ([M - Ph]+), 379.1 ([M - 2Ph]+), 302.0 ([M
- 3Ph]+), 231.0 ([M - 4Ph]+). X-ray crystal data: space
group Pna21, a ) 12.1347(11) Å, b ) 11.7679(11) Å, c )
20.6828(19) Å.23
Cyclotr im er iza tion Rea ction of P h CtCP h . In a typical
reaction, the cluster 1 or 5 and PhCCPh were placed in a
Carius tube with hexane (10 mL), degassed by three freeze-
pump-thaw cycles, and heated for 15 h. The precipitate
obtained was washed with hexane and weighed. For heating
at 150 °C, the reaction mixture was placed in a 43 mL capacity
autoclave under a stream of nitrogen.
Cr ysta l Str u ctu r e Deter m in a tion of 2, 3, 4, a n d 6. The
crystals were grown by slow cooling of CH2Cl2/hexane solutions
and were mounted onto glass fibers. Crystal data and structure
refinement details are given in Table 2. The intensities were
measured on a Siemens SMART diffractometer, equipped with
for 15 h, the color of the solution changed from yellow to red.
Solvent was removed on the vacuum line, and the residue so
obtained was redissolved in the minimum volume of dichlo-
romethane and chromatographed on TLC plates. Elution with
hexane/CH2Cl2 (4:1, v/v) gave unreacted 1 (12.5 mg) and two
novel clusters, viz., Os3(µ-SbPh2)(µ3,η2-CtCBut)(CO)9, 3 (21.2
mg, 37%), and Os5(µ4-Sb)(µ-SbPh2)(µ-H)(µ3,η3-C6H4)(µ,η2-PhCd
C(H)But)(CO)14, 4 (6.8 mg, 14%), as orange crystalline solids.
3: IR (hexane) ν(CO): 2085w, 2060vs, 2044m, 2020vw,
2004s, 1991mw, 1983w, and 1973w cm-1. 1H NMR: δ 7.6-6.9
t
(m, aromatic), 1.67 (s, Bu). Anal. Calcd for C27H19O9Os3Sb:
C, 27.48; H, 1.62. Found: C, 27.65; H, 1.50.
4: IR (hexane) ν(CO): 2094w, 2084s, 2064w, 2057m, 2039vs,
2027m, 2006w, 1984m, 1970w, 1957w cm-1 1H NMR:
. δ
-14.25 (s, 1H, OsHOs). Anal. Calcd for C44H30O14Os5Sb2: C,
26.73; H, 1.53. Found: C, 26.84; H, 1.75.
Rea ction of 1 w ith P h CCP h . To a Carius tube containing
1 (61.7 mg, 0.053 mmol) and PhCCPh (10.7 mg, 0.060 mmol)
was added dichloromethane (10 mL), and the reaction mixture
degassed by three freeze-pump-thaw cycles. After stirring
for 15 h at 90 °C, the color of the solution changed to dark
red. The solvent was removed on the vacuum line, and the
residue obtained was redissolved in the minimum volume of
dichloromethane and chromatographed on TLC plates. Elution
with hexane gave eight bands. The first two bands were
identified from their IR spectra as 5 (2.8 mg, 5.8%) and
unreacted 1 (15.6 mg), respectively.
(23) Bart, J . C. J . Acta Crystallogr., Sect. B 1968, 24, 1277.

1226 Organometallics, Vol. 21, No. 6, 2002
Deng and Leong
a CCD detector, using Mo KR radiation (λ ) 0.71073 Å) at
223(2) K (193(2) K for 3). The data were corrected for Lorentz
and polarization effects with the SMART suite of programs,24
and for absorption effects with SADABS.25 The final unit cell
parameters were obtained by least squares on 8192 (2 and 6),
7435 (3), or 8016 (4) strong reflections. Structural solution and
refinement were carried out with the SHELXTL suite of
programs.26 The structures were solved by direct methods to
locate the heavy atoms, followed by difference maps for the
light, non-hydrogen atoms. All the organic hydrogen atoms
were placed in calculated positions. The position of the metal
hydride in 4 was located in a low-angle difference map and
was refined. A partial molecule of hexane in 6 was located on
a crystallographic center of symmetry and modeled isotropi-
cally; it was given an occupancy of 0.25. The crystal of 2 con-
tained half a CH2Cl2 molecule that was disordered; this was
modeled with two sites of equal occupancy, the C-Cl bonds
were restrained to be equal and the carbon atoms were given
a common isotropic thermal parameter. All non-hydrogen
atoms of the main molecules were given anisotropic displace-
ment parameters in the final refinement. Refinements were
on ∑[w(Fo - Fc2)2]. Atomic coordinates are given in the
2
Supporting Information.
Ack n ow led gm en t. This work was supported by the
National University of Singapore (Research Grant No.
RP 982751), and one of us (M.D.) thanks the University
for a Research Scholarship.
Su p p or tin g In for m a tion Ava ila ble: Experimental and
refinement details for the crystallographic studies, tables of
crystal data and structure refinement, atomic coordinates,
isotropic and anisotropic thermal parameters, complete bond
parameters, and hydrogen coordinates. Crystallographic data
in CIF format. This material is available free of charge via
the Internet at http://pubs.acs.org.
OM010911X
(24) SMART version 4.05; Siemens Energy & Automation Inc.:
Madison, WI, 1996.
(25) Sheldrick, G. M. SADABS; University of Go¨ttingen, 1996.
(26) SHELXTL version 5.03; Siemens Energy & Automation Inc.:
Madison, WI, 1996.