Cluster fragmentation and facile cleavage of phenyl groups from the SnPh3 ligand in reactions of Os3(CO) 11(SnPh3)(μ-H) with CO and HSnPh3

Article abstract of DOI:10.1021/om0603262

Two new cluster complexes, Os₃(CO)₁₂(Ph)(μ ₃-SnPh), 8 (35% yield), and Os₄(CO)₁₆(μ ₄-Sn), 9 (10% yield), were formed when the complex Os ₃(CO)₁₁(SnPh₃)(μ-H), 6, was heated to reflux in toluene solvent under a CO atmosphere. Compound 8 was transformed to 9 in 28% yield when a solution in octane solvent was heated to reflux under a CO atmosphere. Biphenyl was a coproduct in this reaction. Compound 8 contains three osmium atoms with a triply bridging SnPh group. The triosmium cluster has opened and there is only one Os-Os bond between the three osmium atoms. Compound 9 contains two Os₂(CO)₈ groups held together by a central quadruply bridging tin atom, giving an overall bow-tie structure for the five metal atoms. Two other new compounds, Os₂(CO) ₆(μ-SnPh₂)₂(SnPh₃)₂, 10, and HOs(CO)₄(SnPh₃), 11, were formed in 51% and 20% yields, respectively, from the reaction of 6 with HSnPh₃. Compound 10 contains only two osmium atoms linked by an Os-Os bond and two bridging SnPh₂ ligands. Each osmium atom also contains one terminal SnPh ₃ ligand. Compound 11 contains only one osmium atom. It has one SnPh₃ ligartd and a hydrido ligand in cis position in the six-coordinate pseudo-octahedral complex. All four new compounds were characterized by single-crystal X-ray diffraction analysis.

Full text of DOI:10.1021/om0603262

Organometallics 2006, 25, 4183-4187
4183
Cluster Fragmentation and Facile Cleavage of Phenyl Groups from
the SnPh3 Ligand in Reactions of Os3(CO)11(SnPh3)(µ-H) with CO
and HSnPh3
Richard D. Adams,* Burjor Captain, and Lei Zhu
Department of Chemistry and Biochemistry, UniVersity of South Carolina,
Columbia, South Carolina 29208
ReceiVed April 12, 2006
Two new cluster complexes, Os3(CO)12(Ph)(µ3-SnPh), 8 (35% yield), and Os4(CO)16(µ4-Sn), 9 (10%
yield), were formed when the complex Os3(CO)11(SnPh3)(µ-H), 6, was heated to reflux in toluene solvent
under a CO atmosphere. Compound 8 was transformed to 9 in 28% yield when a solution in octane
solvent was heated to reflux under a CO atmosphere. Biphenyl was a coproduct in this reaction. Compound
8 contains three osmium atoms with a triply bridging SnPh group. The triosmium cluster has opened and
there is only one Os-Os bond between the three osmium atoms. Compound 9 contains two Os2(CO)8
groups held together by a central quadruply bridging tin atom, giving an overall bow-tie structure for the
five metal atoms. Two other new compounds, Os2(CO)6(µ-SnPh2)2(SnPh3)2, 10, and HOs(CO)4(SnPh3),
11, were formed in 51% and 20% yields, respectively, from the reaction of 6 with HSnPh3. Compound
10 contains only two osmium atoms linked by an Os-Os bond and two bridging SnPh2 ligands. Each
osmium atom also contains one terminal SnPh3 ligand. Compound 11 contains only one osmium atom.
It has one SnPh3 ligand and a hydrido ligand in cis position in the six-coordinate pseudo-octahedral
complex. All four new compounds were characterized by single-crystal X-ray diffraction analysis.
carbonyl complexes containing large numbers of SnPh2 ligands
of the type a by cleavage of a phenyl group that is eliminated
as benzene.8-10 For example, the reaction of Ru5(CO)15(µ5-C)
with Ph3SnH at 125 °C yielded the complex Ru5(CO)10(SnPh3)-
(µ-SnPh2)4(µ5-C)(µ-H), 1, containing five tin ligands; four are
bridging SnPh2 groups.8 Reactions of Rh4(CO)12 and Ir4(CO)12
with Ph3SnH yielded the M3Sn6 complexes M3(CO)6(µ-SnPh2)3-
(SnPh3)3, 2 (M ) Rh) and 3 (M ) Ir), respectively, containing
three bridging SnPh2 ligands and three terminal SnPh3 ligands.9
Compound 2 reacts still further with Ph3SnH to yield the Rh3-
Sn8 complex Rh3(CO)3(SnPh3)3(µ-SnPh2)3(µ3-SnPh)2, 4, which
contains three terminal SnPh3 ligands, three edge-bridging SnPh2
ligands, and the first examples of triply bridging SnPh ligands
of the type b.9 Cleavage of phenyl groups from the SnPh3 ligand
in Ru5(CO)11(C6H6)(SnPh3)(µ-H)(µ5-C) yielded the complex
Ru5(CO)11(C6H6)(µ4-SnPh)(µ3-CPh), 5, containing the first
example of a quadruply bridging SnPh ligand of the type c.8a
Introduction
Cleavage of phenyl groups from the heteroatoms of phenyl-
containing ligands is an important transformation of metal
complexes1 that can lead to catalyst deactivation when it happens
in complexes being used for homogeneous catalysis.2 Tin is
widely used as a modifier and promoter of homogeneous and
heterogeneous catalysts.3-5 The stepwise hydrogenolysis of tin-
carbon bonds of tetraalkyltin compounds is used to produce tin
alloys of platinum nanoparticles.6 There is evidence that tin can
assist in the binding of metallic nanoparticles to oxide supports
of heterogeneous catalysts.7
In recent work we have shown that reactions of Ph3SnH with
metal carbonyl cluster complexes can lead to polynuclear metal
* To whom correspondence should be addressed. E-mail:
Adams@mail.chem.sc.edu.
(1) (a) Watson, W. H.; Wu, G.; Richmond, M. G. Organometallics 2006,
25, 930. (b) Gainsford, G. J.; Guss, J. M.; Ireland, P. R.; Mason, R.;
Bradford, C. W.; Nyholm, R. S. J. Organomet. Chem. 1972, 40, C70. (c)
Bradford, C. W.; Nyholm, R. S.; Gainsford, G. J.; Guss, J. M.; Ireland, P.
R.; Mason, R. Chem. Commun. 1972, 87.
(2) Garrou, P. E. Chem. ReV. 1985, 85, 171.
(3) (a) Burch, R. J. Catal. 1981, 71, 348. (b) Burch, R.; Garla, L. C. J.
Catal. 1981, 71, 360. (c) Srinivasan, R.; Davis, B. H. Platinum Metals ReV.
1992, 36, 151. (d) Fujikawa, T.; Ribeiro, F. H.; Somorjai, G. A. J. Catal.
1998, 178, 58. (e) Llorca, J.; Homs, N.; Leon, J.; Sales, J.; Fierro, J. L. G.;
Ramirez de la Piscina, P. Appl. Catal. A: Gen. 1999, 189, 77. (f) Recchia,
S.; Dossi, C.; Poli, N.; Fusi, A.; Sordelli, L.; Psaro, R. J. Catal. 1999, 184,
1.
(4) (a) Huber, G. W.; Shabaker, J. W.; Dumesic, J. A. Science 2003,
300, 2075. (b) Holt, M. S.; Wilson, W. L.; Nelson, J. H. Chem. ReV. 1989,
89, 11. (c) Parshall, G. W. J. Am. Chem. Soc. 1972, 94, 8716.
(5) Johnson, B. F. G.; Raynor, S. A.; Brown, D. B.; Shephard, D. S.;
Mashmeyer, T.; Thomas, J. M.; Hermans, S.; Raja, R.; Sankar, G. J. Mol.
Catal. A: Chem. 2002, 182-183, 89.
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G.; Gleeson, D. Angew. Chem., Int. Ed. 2001, 40, 1211. (b) Hungria, A.
B.; Raja, R.; Adams, R. D.; Captain, B.; Thomas, J. M.; Midgley, P. A.;
Golvenko, V.; Johnson, B. F. G. Angew. Chem. Int. Ed. 2006, in press.
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41, 5593. (b) Adams, R. D.; Captain, B.; Fu, W.; Smith, M. D. Inorg. Chem.
2002, 41, 2302.
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(6) (a) Candy, J.-P.; Corperet, C.; Basset, J.-M. Top. Organomet. Chem.
2005, 16, 151. (b) Lesage, P.; Candy, J.-P.; Hirigoyen, C.; Humblot, F.;
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10.1021/om0603262 CCC: $33.50 © 2006 American Chemical Society
Publication on Web 07/13/2006

4184 Organometallics, Vol. 25, No. 17, 2006
Adams et al.
for 10: IR νCO (cm-1 in CH2Cl2): 2051 (m), 2006 (s), 1991 (m,
sh). 1H NMR (in CDCl3): δ 7.08-7.39 (m, 50H, Ph). EI-MS m/z:
1794, and the observed isotope pattern is the same as the theoretical
isotope pattern. Ions corresponding to loss of phenyl and CO ligands
are also observed. Spectral data for 11: IR νCO (cm-1 in CH2Cl2):
2125 (m), 2061 (m), 2038 (s). 1H NMR (in CDCl3): δ 7.27-7.62
We have recently obtained the complexes Os3(CO)11(SnPh3)-
(µ-H), 6, and Os3(CO)9(µ-SnPh2)3, 7, from the reaction of
Os3(CO)12 with Ph3SnH.10 Compound 6 has also been obtained
in a better yield from the reaction of the more reactive triosmium
derivative Os3(CO)11(NCMe) with Ph3SnH.11 We have now
investigated the cleavage of phenyl groups from the SnPh3
ligand in 6. We have found that all three phenyl groups can be
cleaved from the tin atom with the formation of the new “bow-
tie” cluster complex Os4(CO)16(µ4-Sn), which contains a naked
tin atom of the type d serving as a bridge between two Os2-
(CO)8 groups.
2
2
117-H
119-H
)
(m, 15H, Ph), δ -8.94 (s, 1H, JSn
) 55.5 Hz, JSn
57.9 Hz). EI-MS m/z: 654, and the observed isotope pattern is the
same as the theoretical isotope pattern. Ions corresponding to loss
of benzene, CO, and phenyl ligands are also observed.
Reaction of 8 with HSnPh3. A 9.5 mg amount of 8 (0.0081
mmol) and 8.5 mg of HSnPh3 (0.024 mmol) were dissolved in 10
mL of toluene in a 50 mL three-neck flask. The solution was heated
to reflux for 2.5 h. The solvent was removed in vacuo, and the
products were purified by TLC by using a 6:1 hexane-methylene
chloride solvent mixture to yield 1.4 mg (27%) of 11 and 2.2 mg
(16%) of 10. A trace amount of 9 (<1 mg) was also detected.
Experimental Section
General Data. All the reactions were performed under a nitrogen
atmosphere using standard Schlenk techniques. Reagent grade
solvents were dried by standard procedures and were freshly
distilled prior to use. Infrared spectra were recorded on an
Crystallographic Analyses. Colorless single crystals of 8
suitable for diffraction analysis were grown by slow evaporation
of solvent from a benzene-octane solution at 8 °C. Light yellow
single crystals of 9 suitable for diffraction analysis were grown by
slow evaporation of solvent from a CH2Cl2-hexane solution at 8
°C. Orange single crystals of 10 were grown by slow evaporation
of solvent from a benzene-octane solution at 8 °C. Colorless single
crystals of 11 were grown from a solution in a CH2Cl2-hexane
solvent mixture by cooling to -20 °C. The data crystals used in
the analyses were glued onto the end of a thin glass fiber. X-ray
intensity data were measured using a Bruker SMART APEX CCD-
based diffractometer using Mo KR radiation (λ ) 0.71073 Å). The
raw data frames were integrated with the SAINT+ program by
using a narrow-frame integration algorithm.12 Corrections for the
Lorentz and polarization effects were also applied by SAINT. An
empirical absorption correction based on the multiple measurement
of equivalent reflections was applied by using the program
SADABS. All structures were solved by a combination of direct
methods and difference Fourier syntheses and refined by full-matrix
least-squares on F2, by using the SHELXTL software package.13
Crystal data, data collection parameters, and results of the structural
analyses for compound 8-11 are listed in Tables 1 and 2. For each
structure all non-hydrogen atoms were refined with anisotropic
displacement parameters. The hydrogen atoms on all phenyl rings
were placed in geometrically idealized positions and included as
standard riding atoms.
1
AVATAR 360 FT-IR spectrophotometer. H NMR was recorded
on a Varian Mercury 300 spectrometer operating at 300 MHz. Mass
spectrometric measurements performed by direct exposure probe
using electron impact ionization (EI) were made on a VG 70S
instrument. Ph3SnH was purchased from Aldrich and was used
without further purification. Os3(CO)11(SnPh3)(µ-H) was prepared
according to the previously reported procedure.10,11 Product separa-
tions were performed by TLC in air on Analtech 0.25 and 0.5 mm
silica gel 60 Å F254 glass plates.
Preparation of Os3(CO)12(Ph)(µ3-SnPh), 8, and Os4(CO)16-
(µ4-Sn), 9. A 50 mg amount of 6 (0.041 mmol) dissolved in 20
mL of toluene was heated to reflux under a slow purge of CO for
10 h. The products were purified by TLC on silica gel using a 6:1
hexane-methylene chloride solvent mixture to yield in order of
elution 5.0 mg (10% yield) of 9 and 17 mg (35% yield) of 8.
Spectral data for 8: IR νCO (cm-1 in CH2Cl2): 2128 (w), 2102 (m),
2066 (s), 2048 (m), 2029 (m), 2017 (m), 1996 (w, sh), 1981 (w,
sh). 1H NMR (in CDCl3): δ 6.88-7.70 (m, 10H, Ph). EI-MS m/z:
1180 with ions corresponding to consecutive loss of 12 CO ligands
and the two phenyl groups. For 9: IR νCO (cm-1 in CH2Cl2): 2095
(m), 2069 (vs), 2027 (s), 2005 (m). EI-MS m/z: 1328 with ions
corresponding to consecutive loss of 16 CO ligands.
Conversion of 6 to 8 and 9 under CO (110 psi). A 16 mg
amount of 6 (0.013 mmol) was dissolved in 2 mL of toluene-d8.
1H NMR of this solution showed multiple resonances in the region
δ 7.15-7.76, corresponding to the protons on the phenyl rings.
The solution was then sealed in a stainless steel Parr pressure reactor
under CO atmosphere (100 psi) and placed in an oil bath at 130
°C for 2 h. The Parr reactor was then cooled to room temperature.
1H NMR of the reaction mixture showed a resonance at δ 7.134,
indicating the formation of benzene during the reaction. Compounds
8 and 9 were generated in 20% and 16% yields, respectively.
Conversion of 8 to 9. A 20 mg amount of 8 (0.017 mmol) was
dissolved in 10 mL of octane in a 50 mL three-neck flask. The
solution was heated to reflux under CO atmosphere (1 atm) for 2
h. The solvent was removed in vacuo, and the products were
purified by TLC using a 6:1 hexane-methylene chloride solvent
mixture to yield 5.8 mg (28%) of 9 and 0.9 mg (34%) of biphenyl.
Preparation of Os2(CO)6(µ2-SnPh2)2(SnPh3)2, 10, and HOs-
(CO)4SnPh3, 11. An 11 mg amount of 6 (0.0093 mmol) was
dissolved in 10 mL of toluene in a 50 mL three-neck flask. An
excess amount of HSnPh3 was added, and the reaction was heated
to reflux for 1 h. The solvent was removed in vacuo, and the
products were purified by TLC on silica gel using a 6:1 hexane-
methylene chloride solvent mixture to yield in order of elution 1.2
mg (20% yield) of 11 and 8.5 mg (51% yield) of 10. Spectral data
Compound 8 crystallized in the triclinic crystal system. The space
group P1h was assumed and confirmed by the successful solution
and refinement of the structure.
Compound 9 crystallized in the monoclinic crystal system. The
systematic absences in the intensity data were consistent with the
space groups C2/c and Cc. The former space group was chosen
and confirmed by the successful solution and refinement of the
structure.
Compound 10 crystallized in the triclinic crystal system. The
space group P1h was assumed and confirmed by the successful
solution and refinement of the structure. The molecule is crystal-
lographically centrosymmetrical and contains one-half of the
formula equivalent of the molecule in the asymmetric crystal unit.
Also, one molecule of benzene from the crystallization solvent was
cocrystallized in the asymmetric unit.
Compound 11 crystallized in the triclinic crystal system. The
space group P1h was assumed and confirmed by the successful
solution and refinement of the structure. The hydride ligand was
located and refined with an isotropic thermal parameter.
(12) SAINT+, version 6.2a; Bruker Analytical X-ray Systems, Inc.:
Madison, WI, 2001.
(11) Burgess, K.; Guerin, C.; Johnson, B. F. G.; Lewis, J. J. Organomet.
Chem. 1985, 295, C3.
(13) Sheldrick, G. M. SHELXTL, version 6.1; Bruker Analytical X-ray
Systems, Inc.: Madison, WI, 1997.

Reactions of Os3(CO)11(SnPh3)(µ-H) with CO and HSnPh3
Organometallics, Vol. 25, No. 17, 2006 4185
Table 1. Crystallographic Data for Compounds 8 and 9
8
9
empirical formula
fw
Os3SnO12C24H10
1179.61
Os4SnO16C16
1327.65
cryst syst
lattice params
a (Å)
b (Å)
c (Å)
triclinic
monoclinic
9.4672(5)
9.5559(5)
18.1476(9)
89.988(1)
81.515(1)
64.473(1)
1461.59(13)
P1h
32.3449(12)
10.1687(4)
17.0856(6)
90
110.1970(10)
90
5274.0(3)
C2/c
8
3.344
20.207
294(2)
56.6
5106
R (deg)
â (deg)
γ (deg)
V (Å3)
space group
Z value
2
F
calc (g/cm3)
2.680
13.900
293(2)
56.6
5438
361
µ(Mo KR) (mm-1
temperature (K)
2θmax (deg)
)
no. obsd (I > 2σ(I))
no. params
Figure 1. ORTEP diagram of Os3(CO)12(Ph)(µ3-SnPh), 8, showing
30% probability thermal ellipsoids. Selected interatomic distances
(Å) and angles (deg): Os(1)-Os(2) ) 3.0007(4), Os(1)-Sn(1) )
2.7240(6), Os(2)-Sn(1) ) 2.7283(6), Os(3)-Sn(1) ) 2.7532(6),
Os(3)-C(41) ) 2.172(9); Os(1)-Sn(1)-Os(3) ) 126.597(19),
Os(2)-Sn(1)-Os(3) ) 128.81(2), C(41)-Os(3)-Sn(1) ) 82.8(2).
334
goodness of fit
max. shift in cycle
residuals:a R1; wR2
absorp corr,
1.043
0.001
0.0349; 0.0722
SADABS
1.000/0.519
1.586
1.053
0.000
0.0354; 0.0693
SADABS
1.000/0.595
3.052
max./min.
largest peak in final
diff map (e-/Å3)
a R1 ) ∑hkl(||Fobs| - |Fcalc||)/∑hkl|Fobs|; wR2 ) [∑hklw(|Fobs| - |Fcalc|)2/
2
∑
n
hklwFobs
]
1/2, w ) 1/σ2(Fobs); GOF ) [∑hklw(|Fobs| - |Fcalc|)2/(ndata
-
vari)]1/2
.
Table 2. Crystallographic Data for Compounds 10 and 11
10
11
empirical formula
fw
Os2Sn4O6C66H50‚2C6H6
1950.44
OsSnO4C22H16
653.24
cryst syst
lattice params
a (Å)
b (Å)
c (Å)
triclinic
triclinic
11.2240(3)
11.3303(3)
16.0970(4)
93.721(1)
109.943(1)
110.146(1)
1767.59(8)
P1h
9.6670(4)
10.8704(4)
11.2785(4)
67.827(1)
88.862(1)
83.898(1)
1091.06(7)
P1h
R (deg)
â (deg)
γ (deg)
V (Å3)
space group
Z value
Figure 2. ORTEP diagram of Os4(CO)16(µ4-Sn), 9, showing 30%
probability thermal ellipsoids. Selected interatomic distances (Å)
and angles (deg): Os(1)-Os(2) ) 3.0081(5), Os(1)-Sn(1) )
2.6927(7), Os(2)-Sn(1) ) 2.6883(7), Os(3)-Os(4) ) 3.0038(5),
Os(3)-Sn(1) ) 2.6983(7), Os(4)-Sn(1) ) 2.6797(7); Os(4)-Sn-
(1)-Os(2) ) 136.86(3), Os(4)-Sn(1)-Os(1) ) 135.85(2), Os(2)-
Sn(1)-Os(1) ) 67.975(17), Os(4)-Sn(1)-Os(3) ) 67.907(18),
Os(2)-Sn(1)-Os(3) ) 130.34(3), Os(1)-Sn(1)-Os(3) ) 130.32(2).
1
2
F
calc (g/cm3)
1.832
5.022
293(2)
55.8
7724
406
1.988
6.985
294(2)
56.6
4947
257
µ(Mo KR) (mm-1
temperature (K)
2θmax (deg)
)
no. obsd (I > 2σ(I))
no. params
goodness of fit
max. shift in cycle
residuals:a R1; wR2
absorp corr,
1.149
0.002
0.0198; 0.0496
SADABS
1.000/0.773
0.962
1.051
0.002
0.0195; 0.0469
SADABS
1.000/0.708
1.298
connected by a triply bridging SnPh group. There is only one
Os-Os bond, Os(1)-Os(2) ) 3.0007(4) Å, which connects two
of the Os(CO)4 groups. There is a phenyl group σ-bonded to
the third Os(CO)4 group, Os(3)-C(41) ) 2.172(9) Å. The Os-
Sn bond distances, Os(1)-Sn(1) ) 2.7240(6) Å, Os(2)-Sn(1)
) 2.7283(6) Å, Os(3)-Sn(1) ) 2.7532(6) Å, are slightly longer
than the Os-Sn distance to the SnPh3 group in 6, Os(1)-Sn(1)
) 2.6949(6) Å.10
max./min.
largest peak in final
diff map (e-/Å3)
a R1 ) ∑hkl(||Fobs| - |Fcalc||)/∑hkl|Fobs|; wR2 ) [∑hklw(|Fobs| - |Fcalc|)2/
2
∑
n
hklwFobs
]
1/2, w ) 1/σ2(Fobs); GOF ) [∑hklw(|Fobs| - |Fcalc|)2/(ndata
-
vari)]1/2
.
Compound 8 is a precursor to 9. It was transformed to 9 in
28% yield when a solution in octane solvent was heated to reflux
under an atmosphere of CO. Biphenyl was observed as a
coproduct from this reaction and was obtained in a yield (34%)
that is similar to the yield of 9. Compound 9 was also
characterized by a single-crystal X-ray diffraction analysis, and
an ORTEP diagram of its molecular structure is shown in Figure
2. Compound 9 contains two Os2(CO)8 groups held together
by a central quadruply bridging tin atom, giving an overall bow-
tie structure for the five metal atoms. The complex has
Results and Discussion
Two new cluster complexes, Os3(CO)12(Ph)(µ3-SnPh), 8 (35%
yield), and Os4(CO)16(µ4-Sn), 9 (10% yield), were formed when
the complex Os3(CO)11(SnPh3)(µ-H), 6, was heated to reflux
in toluene solvent under a CO atmosphere for 10 h. Benzene
was observed as a coproduct from this reaction. Compound 8
was characterized by single-crystal X-ray diffraction analysis.
An ORTEP diagram of the molecular structure of 8 is shown
in Figure 1. The molecule contains three Os(CO)4 groups

4186 Organometallics, Vol. 25, No. 17, 2006
Adams et al.
Figure 3. ORTEP diagram of Os2(CO)6(µ-SnPh2)2(SnPh3)2, 10,
showing 30% probability thermal ellipsoids. Selected interatomic
distances (Å) and angles (deg) Os(1)-Os(1*) ) 3.1471(2), Os(1)-
Sn(1) ) 2.6789(2), Os(1)-Sn(2) ) 2.7253(2), Os(1)-Sn(1*) )
2.7593(2); Sn(1)-Os(1)-Sn(1*) ) 109.301(6); Sn(2)-Os(1)-Sn-
(1*) ) 162.888(8), Sn(2)-Os(1)-Os(1*) ) 142.214(7).
Figure 4. ORTEP diagram of HOs(CO)4(SnPh3), 11, showing 30%
probability thermal ellipsoids. Selected interatomic distances (Å)
and angles (deg): Os(1)-Sn(1) ) 2.7382(2), Os(1)-H(1) )
1.67(4), Os(1)-C(11) ) 1.944(3), Os(1) - C(12) ) 1.967(3),
Os(1)-C(13) ) 1.948(3), Os(1)-C(14) ) 1.942(3); Sn(1)-Os-
(1)-H(1) ) 79.3(12).
approximate D2d symmetry, which is not crystallographically
imposed. The Os-Os bond distances, Os(1)-Os(2) ) 3.0081(5)
Å and Os(3)-Os(4) ) 3.0038(5) Å, are very similar to that in
8. The four Os-Sn bond distances are slightly shorter than those
in 8, Os(1)-Sn(1) ) 2.6927(7) Å, Os(2)-Sn(1) ) 2.6883(7)
Å, Os(3)-Sn(1) ) 2.6983(7) Å, Os(4)-Sn(1) ) 2.6797(7) Å,
but are very similar to those in the compound Os3(CO)9(µ-H)3-
(µ4-Sn)Os3(CO)10(PEt2Ph)(µ-H), 10, which contains a tin atom
bridging the triangle of one Os3 cluster with a bond to one
osmium atom of a second triangular Os3 cluster.14 Some related
iron compounds containing similar quadruply bridging tin atoms
have been reported, e.g., Fe2(CO)8(µ4-Sn)Fe2(CO)8,15 Fe2(CO)8-
(µ4-Sn)Fe2(CO)7(µ4-Sn)Fe2(CO)8,16 [NEt4][Fe2(CO)8(µ4-Sn){Fe-
(CO)4}2],17 Fe2(CO)8(µ4-Sn)Fe3(CO)11,18 and [Fe2(CO)8(µ3-
SnMe2)]2(µ4-Sn).19 These were obtained by a variety of different
procedures.
When compound 6 was treated with Ph3SnH, two new
compounds, Os2(CO)6(µ-SnPh2)2(SnPh3)2, 10, and HOs(CO)4-
(SnPh3), 11, were formed in 51% and 20% yields, respectively.
Both compounds were characterized crystallographically. An
ORTEP diagram of the structure of 10 is shown in Figure 3. In
the solid state, the structure of 10 is crystallographically
centrosymmetrical. Each osmium atom contains one terminal
SnPh3 ligand, Os(1)-Sn(2) ) 2.7253(2) Å, and three linear
terminal carbonyl ligands. The two SnPh3 ligands have an
overall trans geometry with respect to the Os-Os bond. The
molecule contains two bridging SnPh2 ligands positioned on
opposite sides of the molecule. The Os(1)-Sn(1*) bond that is
trans to the terminal SnPh3 ligand is considerably longer than
the Os-Sn bond that is terminal to a CO ligand, Os(1)-Sn(1)
) 2.6789(2) Å and Os(1)-Sn(1*) ) 2.7593(2) Å. To obey the
18-electron configurations, the two osmium atoms should
contain an Os-Os single bond. Although the Os-Os distance,
Os(1)-Os(1*) ) 3.1471(2) Å, is certainly short enough to be
considered a bonding distance, it is considerably longer than
the Os-Os bond distances in 8 and 9 and also in Os3(CO)12,
2.877(3) Å;20 Os3(CO)12 has no bridging ligands. It is even
longer than the three Os-Os bonds in 7, Os(1)-Os(2) )
2.9629(4) Å, Os(1)-Os(3) ) 2.9572(4) Å, Os(2)-Os(3) )
2.9906(4) Å. We have found in previous studies that metal-
metal bonds containing bridging SnPh2 tend to be longer than
the corresponding unbridged metal-metal bonds.9,21 Theoretical
analyses have indicated that this is due to the presence of strong
M-Sn bonding interactions that compete with the M-M
bonding interactions.9 The Re-Re bond in the compound Re2-
(CO)8(µ-SnPh2)2 is also unusually long.21 Compound 10 is
structurally similar to the related known ruthenium compound
Ru2(CO)6(µ-SnMe2)2(SnMe3)2.22
An ORTEP diagram of the structure of 11 is shown in Figure
4. Compound 11 contains only one osmium atom. It has a six-
coordinate pseudo-octahedral coordination with four carbonyl
ligands, and one SnPh3 ligand and a hydrido ligand that are
positioned cis to one another. The Os-Sn bond is very similar
in length to that in 10, Os(1)-Sn(1) ) 2.7382(2) Å. The hydrido
ligand was located and refined crystallographically, Os(1)-H(1)
1
) 1.67(4) Å. Its resonance in the H NMR spectrum exhibits
the characteristic high-field shift, δ ) -8.94 (s, 1H), with two
bond couplings to tin, 2JSn -H ) 55.5 Hz, 2JSn -H ) 57.9 Hz.
A summary of the transformations reported here is shown in
Scheme 1. We have demonstrated that all of the phenyl groups
can be cleaved from a triphenyltin ligand to produce a naked
tin atom serving as a bridging ligand between four osmium
atoms. All of the details of the mechanism of the formation of
8 and 9 from 6 are not yet known, but the formation of benzene
is consistent with our previous observations where benzene and
bridging SnPh2 ligands were formed from reactions involving
HSnPh3.8 In the present reaction, additional cleavages of the
117
119
(14) Leong, W. K.; Einstein, F. W. B.; Pomeroy, R. K. J. Cluster Sci.
1996, 7, 211.
(15) (a) Cotton, J. D.; Duckworth, J.; Knox, S. A. R.; Lindley, P. F.;
Paul, I.; Stone, F. G. A.; Woodward, P. J. Chem. Soc., Chem. Commun.
1966, 253. (b) Lindley, P. F.; Woodward, P. J. Chem. Soc. A 1967, 382.
(16) Anema, S. G.; Mackay, K. M.; Nicholson, B. K. Inorg. Chem. 1989,
28, 3158.
(17) Cassidy, J. M.; Whitmire, K. H.; Kook, A. M. J. Organomet. Chem.
1993, 456, 61.
(18) Anema, S. G.; Mackay, K. M.; Nicholson, B. K. J. Organomet.
Chem. 1989, 372, 25.
(19) Sweet, R. M.; Fritchie, C. J.; Schunn, R. A. Inorg. Chem. 1967, 6,
749.
(20) Churchill, M. R.; DeBoer, B. G. Inorg. Chem. 1977, 16, 878.
(21) (a) Adams, R. D.; Captain, B.; Herber, R. H.; Johansson, M.; Nowik,
I.; Smith, J. L., Jr.; Smith, M. D. Inorg. Chem. 2005, 44, 6346. (b) Adams,
R. D.; Captain, B.; Johansson, M.; Smith, J. L., Jr. J. Am. Chem. Soc. 2005,
127, 488.
(22) Watkins, S. F. J. Chem. Soc. A 1969, 1552.

Reactions of Os3(CO)11(SnPh3)(µ-H) with CO and HSnPh3
Organometallics, Vol. 25, No. 17, 2006 4187
Scheme 1
phenyl groups from the tin atom occur. In particular, in the
formation of 8, one phenyl group was also transferred from the
tin atom to one of the osmium atoms. A CO ligand was also
added, which led to an opening of the Os3 cluster. Compounds
8 and 9 were also obtained when 6 was heated in the absence
of CO, but the yields were much lower because of the lack of
CO required for their formation. Compound 8 was transformed
to 9, which has no phenyl rings. Since there are no available
hydrido ligands for the formation of benzene from 8, the two
phenyl rings were combined instead and were eliminated in the
form of biphenyl. The number of Os(CO)4 groups was increased
by one on going from 8 to 9. The nature of this transformation
is not clear. This could occur by transfer of an Os(CO)4 group
from a second molecule of 8 or by an exchange of an Os2-
(CO)8 group for an Os(CO)4 group from a second molecule of
8 in the course of the elimination of the biphenyl.
The compounds that we have reported here show a sequence
of steps for the incorporation of a naked tin into the tetraosmium
complex 9. Even though cluster fragmentation does occur in
this reaction sequence, the nature of tin-carbon bond cleavages
may be relevant to the incorporation of tin atoms into higher
nuclearity clusters and transition metal nanoparticles from
organotin reagents in general.4a,6 The facile cleavage of phenyl
rings from phenyltin ligands may prove to be an effective route
to new families of metal carbonyl cluster complexes containing
naked bridging tin atoms. Tin-containing cluster complexes are
now proving to be useful precursors to new supported bi- and
trimetallic heterogeneous catalysts.7
Acknowledgment. This research was supported by the
Office of Basic Energy Sciences of the U.S. Department of
Energy under Grant No. DE-FG02-00ER14980.
Supporting Information Available: CIF files for each of the
structural analyses are available. This material is available free of
charge via the Internet at http://pubs.acs.org.
Compounds 10 and 11 were both obtained also from the
reaction of 8 with HSnPh3. Indeed, the opening of the Os3
triangle to form 8 may be the first step in the fragmentation
process that leads to 10 and 11 in the reaction of 6 with HSnPh3.
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