Diruthenium-tin complexes from the reaction of Ph2SnH 2 with Ru(CO)5 and their reactions with bis(tri-teri-butylphosphine)platinum

Article abstract of DOI:10.1021/om800385w

Ph₂SnH₂ reacts with 2 equiv of Ru(CO)₅ to give the compound [Ru(CO)₄H]₂(μ-SnPh₂) (1) in 57% yield by loss of CO from each molecule of Ru(CO)₅ and by an oxidative addition of an Sn-H bond to each ruthenium atom. When compound 1 was irradiated with visible radiation, the compound Ru₂(CO) ₈(μ-SnPh₂) (2) was obtained by loss of hydrogen. A mechanism involving loss of CO followed by loss of H₂ and readdition of CO is supported by isotopic labeling studies. Compound 1 reacts with Pt(PBu^t₃)₂ to yield the new trimetallic compound Ru₂(CO)₇(μ-SnPh₂)(μ-H) ₂(μ-PtPBu^t₃) (3). Compound 3 contains a Pt(CO)(PBu^t₃) group bridging the Ru-Ru bond and two bridging hydrido ligands. Compound 2 reacts With Pt(PBu^t ₃)₂ to yield the two products PtRu₂(CO) ₈)(PBu^t₃)(μ-SnPh₂)(4; 78% yield) and Pt₂Ru₂(CO)₈(PBu^t ₃)₂(μ-SnPh₂) (5; 15% yield) by the addition of one and two Pt(PBu^t₃) groups to the metal-metal bonds of 2. The first Pt(PBu^t₃) addition occurs at the Ru-Ru bond to form 4. The second Pt(PBu^t₃) addition occurs at one of the Ru-Sn bonds. Compound 4 reacts with hydrogen under irradiation with visible light to yield 3. Fenske-Hall molecular orbitais were calculated for the compounds 2-5. The molecular orbital analysis of 2 explains the nature of the addition of the Pt(PBu^t₃) groups to its metal-metal bonds. The molecular structures of 1-5 were determined by single-crystal X-ray diffraction analysis.

Full text of DOI:10.1021/om800385w

4108
Organometallics 2008, 27, 4108–4115
Diruthenium-Tin Complexes from the Reaction of Ph2SnH2 with
Ru(CO)5 and Their Reactions with
Bis(tri-tert-butylphosphine)platinum
Richard D. Adams* and Eszter Trufan
Department of Chemistry and Biochemistry, UniVersity of South Carolina,
Columbia, South Carolina 29208
ReceiVed May 1, 2008
Ph2SnH2 reacts with 2 equiv of Ru(CO)5 to give the compound [Ru(CO)4H]2(µ-SnPh2) (1) in 57%
yield by loss of CO from each molecule of Ru(CO)5 and by an oxidative addition of an Sn-H bond to
each ruthenium atom. When compound 1 was irradiated with visible radiation, the compound Ru2(CO)8(µ-
SnPh2) (2) was obtained by loss of hydrogen. A mechanism involving loss of CO followed by loss of H2
and readdition of CO is supported by isotopic labeling studies. Compound 1 reacts with Pt(PBut3)2 to
yield the new trimetallic compound Ru2(CO)7(µ-SnPh2)(µ-H)2(µ-PtPBut3) (3). Compound 3 contains a
Pt(CO)(PBut3) group bridging the Ru-Ru bond and two bridging hydrido ligands. Compound 2 reacts
withPt(PBut3)2toyieldthetwoproductsPtRu2(CO)8)(PBut3)(µ-SnPh2)(4;78%yield)andPt2Ru2(CO)8(PBut3)2(µ-
SnPh2) (5; 15% yield) by the addition of one and two Pt(PBut3) groups to the metal-metal bonds of 2.
The first Pt(PBut3) addition occurs at the Ru-Ru bond to form 4. The second Pt(PBut3) addition occurs
at one of the Ru-Sn bonds. Compound 4 reacts with hydrogen under irradiation with visible light to
yield 3. Fenske-Hall molecular orbitals were calculated for the compounds 2-5. The molecular orbital
analysis of 2 explains the nature of the addition of the Pt(PBut3) groups to its metal-metal bonds. The
molecular structures of 1-5 were determined by single-crystal X-ray diffraction analysis.
Introduction
In recent studies we have shown that the tin hydride
compound Ph3SnH reacts readily with polynuclear metal car-
bonyl cluster complexes to yield higher nuclearity cluster
complexes containing large numbers of tin-containing ligands
(eqs 1–3).1–3 The bridging tin ligands SnPh2,1–5 SnPh,2,3 and
even naked Sn6 are commonly formed by the cleavage of one
to three of the Ph groups from the tin atom.
It has been shown that some of these tin-containing complexes
can serve as precursors to di- and trimetallic nanoparticles that
exhibit high activity and selectivity for certain types of catalytic
hydrogenation reactions.2,7
* To whom correspondence should be addressed. E-mail:
Adams@mail.chem.sc.edu.
(1) Adams, R. D.; Captain, B.; Fu, W.; Smith, M. D. Inorg. Chem. 2002,
41, 2302–2303.
(2) Adams, R. D.; Boswell, E. M.; Captain, B.; Hungria, A. B.; Midgley,
P. A.; Raja, R.; Thomas, J. M. Angew. Chem., Int. Ed. 2007, 46, 8182–
8185.
(3) Adams, R. D.; Captain, B.; Hall, M. B.; Webster, C. E. Inorg. Chem.
2004, 43, 7576–7578.
t
We have also found that it is possible to add Pd(PBu3 ) and
t
Pt(PBu3 ) groups to transition-metal-tin bonds by reactions with
t
t
the compounds Pd(PBu3 )2 and Pt(PBu3 )2: e.g., eqs 48 and 5.4
We have also found that Pd(PBut3)2 and Pt(PBut3)2 can
activate the M-H bond of the tin-containing metal carbonyl
(4) Adams, R. D.; Captain, B.; Herber, R. H.; Johansson, M.; Nowik,
I., Jr.; Smith, M. D. Inorg. Chem. 2005, 44, 6346–6358.
(5) Adams, R. D.; Captain, B.; Zhu, L. Organometallics 2006, 25, 2049–
2054.
(6) Adams, R. D.; Captain, B.; Zhu, L. Organometallics 2006, 25, 4183–
4187.
(7) (a) 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, 45, 4782–4785. (b) Thomas, J. M.; Johnson, B. F. G.; Raja, R.;
Sankar, G.; Midgley, P. A. Acc. Chem. Res. 2003, 36, 20–30.
(8) Adams, R. D.; Captain, B.; Hall, M. B.; Trufan, E.; Yang, X. J. Am.
Chem. Soc. 2007, 129, 12328–12340.
10.1021/om800385w CCC: $40.75
2008 American Chemical Society
Publication on Web 07/23/2008

Diruthenium-Tin Complexes
Organometallics, Vol. 27, No. 16, 2008 4109
0 °C. The solution was then heated to reflux for 30 min, during
which time the colorless solution turned orange. After cooling, the
solvent was removed in vacuo and the product was purified by TLC
by using a 6:1 hexane-methylene chloride solvent mixture to yield
48.8 mg (57%) of pale orange 1. Note: the TLC separation should
be performed in the dark, because compound 1 is light sensitive.
Spectral data for 1 are as follows. IR νCO (cm-1 in hexane): 2119
(w), 2105 (s), 2057 (s, sh), 2045 (vs), 2038 (s, sh), 2026 (s, sh).
1H NMR (CDCl3, in ppm): δ 7.22-7.65 (m, 10 H, Ph), -7.63 (s,
2
2
117
119
2H, hydride, J Sn-H ) 55 Hz, J Sn-H ) 52.2 Hz). EI-MS:
m/z 702 M+ (parent ion, weak); 674, M+ - CO; 644, M+ - 2CO
- H2; 616, M+ - 3CO - H2; 560, M+ - 5CO - H2; 532, M+
6CO - H2; 504, M+ - 7CO - H2; 476, M+ - 8CO - H2.
-
Irradiation of 1 under CO. A 15.4 mg amount of 1 was
dissolved in 15 mL of benzene in a 100 mL three-neck flask. The
pale yellow solution was irradiated with a 100 W sunlamp for 35
min under a CO atmosphere. The reaction was monitored by IR
spectroscopy and was stopped when the peaks corresponding to
the starting material had disappeared. The solvent was then removed
in vacuo, and the product was isolated by TLC by using a 6:1
hexane-methylene chloride solvent mixture to yield 7.9 mg (51%)
of pale yellow Ru2(CO)8(µ-SnPh2) (2). Note: the TLC separation
should be performed in the dark, because 2 is light sensitive.
Spectral data for 2 are as follows. IR νCO (cm-1 in hexane): 2107
(w), 2066 (s), 2045 (vs), 2037 (m, sh), 2028 (vs), 2021 (w, sh),
hydride complexes HM(CO)4SnPh3 (M ) Ru, Os) toward
insertion of alkynes into the metal-hydrogen bond. It was
shown that the M(PBut3) group (M ) Pd, Pt) activates the M-H
bond by forming a complex to it prior to the addition/insertion
of the alkyne: e.g., eq 6.9
1
2011 (w), 1999 (w). H NMR (CDCl3, in ppm): δ 7.22-7.65 (m,
10 H, Ph). EI-MS: m/z 700 (parent ion).
We have now investigated the reaction of Ph2SnH2 with
Ru(CO)5 and have obtained the new diruthenium-tin complex
[Ru(CO)4H]2(µ-SnPh2) (1) by oxidative addition of the Sn-H
bonds to the ruthenium atoms. Compound 1 loses hydrogen
upon irradiation to yield the compound Ru2(CO)8(µ-SnPh2) (2).
The synthesis and characterization of these compounds and
investigations of their reactions with Pt(PBut3)2 are described
in this report.
Irradiation of 1 under N2 in an NMR Tube. A 38.6 mg amount
of 1 was dissolved in d6-benzene in a NMR tube. The NMR tube
was evacuated and then filled with nitrogen. The purity of the
1
starting material was confirmed by H NMR. The solution in the
tube was then irradiated with a 100 W sunlamp for 50 min. After
this time, another 1H NMR spectrum was recorded. This spectrum
showed a prominent peak at 4.46 ppm that corresponds to the
chemical shift of H2 in d6-benzene. The solvent was then removed
in vacuo, and the product was separated by TLC by using a 6:1
hexane-methylene chloride solvent mixture to yield 5.2 mg (14%)
of pale yellow 2.
Experimental Section
General Data. All the reactions were performed under a nitrogen
atmosphere by using the standard Schlenk techniques. Reagent
grade solvents were dried by the standard procedures and were
freshly distilled prior to use. Infrared spectra were recorded on an
AVATAR 360 FT-IR spectrophotometer. 1H NMR and 31P NMR
were recorded on a Varian Mercury 400 spectrometer operating at
399 and 162 MHz, respectively. 31P NMR spectra were externally
referenced against 85% ortho-H3PO4. Mass spectrometric measure-
ments were performed on a VG 70S instrument by using direct
exposure probe and electron impact ionization (EI). Ru3(CO)12 and
Pt(PBut3)2 were purchased from Strem and were used without
further purifications. Ph2SnH2 was prepared according to a previ-
ously published procedure.10 Product separations were performed
in air by TLC on glass plates by using Analtech silica gel 60 Å
F254, 0.25 mm thickness.
Synthesis of [Ru(CO)4H]2(µ-SnPh2) (1). A solution of Ru(CO)5
was prepared and used in situ as follows:11 a 51.7 mg amount of
Ru3(CO)12 (0.081 mmol) was dissolved in 120 mL of hexane in a
250 mL Pyrex three-neck flask. The solution was placed in an ice
bath and irradiated using a medium-pressure mercury UV lamp
(1000 W) in the presence of a slow purge of carbon monoxide
(CO) for approximately 25 min. During this time the orange solution
turned colorless. The reaction flask was then evacuated and refilled
with nitrogen to remove the excess CO. A 70.0 mg amount of
H2SnPh2 (0.254 mmol) was then added to the Ru(CO)5 solution at
Preparation of Ru2(CO)7(µ-SnPh2)(µ-H)2(µ-PtPBut3) (3). A
14.0 mg (0.020 mmol) amount of 1 was dissolved in 30 mL of
hexane in a 100 mL three-neck flask. To this solution was added
a 12.0 mg (0.020 mmol) amount of Pt(PBut3)2, and the mixture
was stirred at room temperature for 10 min. The pale yellow solution
turned orange. The solvent was then removed in vacuo, and the
product was purified by TLC by using a 6:1 hexane-methylene
chloride solvent mixture to yield 14.6 mg (76%) of orange
Ru2(CO)7(µ-SnPh2)(µ-H)2(µ-PtPBut3) (3). Spectral data for 3 are
as follows. IR νCO (cm-1 in hexane): 2070 (m), 2043 (s), 2007
1
(m), 1987 (m, sh). H NMR (CDCl3, in ppm): δ 7.16-7.53 (m,
3
10H, Ph), 1.17 (d, 27H, CH3, JP-H ) 13 Hz), -11.63 (t, 1H,
hydride, 2JH-H ) 2.3 Hz), -12.44 (dd, 1 H, hydride, 2JH-H ) 2.3
3
Hz, JP-H ) 13 Hz). EI-MS: m/z 1072 (parent ion).
Preparation of PtRu2(CO)8)(PBut3)(µ-SnPh2) (4) and
Pt2Ru2(CO)8)(PBut3)2(µ-SnPh2) (5). An 11.0 mg (0.016 mmol)
amount of 2 was dissolved in 20 mL of methylene chloride in a
100 mL three-neck flask. To this solution was added 10.0 mg (0.017
mmol) of Pt(PBut3)2, and the mixture was stirred for 70 min at
room temperature in the dark. During this time the starting pale
yellow solution turned to a dark orange. The solvent was then
removed, and the products were separated by TLC by using a 6:1
hexane-methylene chloride solvent mixture to yield 13.5 mg of
orange 4 (78%) and 3.5 mg of red 5 (15%) Spectral data for 4 are
as follows. IR νCO (cm-1 in CH2Cl2): 2086 (vw), 2053 (s), 2015
(vs), 1986 (m), 1826 (m), 1810 (m). 1H NMR (CDCl3, in ppm): δ
(9) Adams, R. D.; Captain, B.; Trufan, E.; Zhu, L. J. Am. Chem. Soc.
2007, 129, 7545–7556.
(10) Herna´n, A.; Horton, P.; Hursthouse, M. B.; Kilburn, J. D. J.
Organomet. Chem. 2006, 691, 1466–1475.
(11) Huq, R.; Poe¨, A. J.; Chawla, S. Inorg. Chim. Acta 1980, 38, 121–
125.
3
7.33-7.66 (m, 10H, Ph), 1.51 (d, 27H, CH3, JP-H ) 13 Hz).
1
31P{1H} NMR (in CDCl3, ppm): δ 107.02 (s, 1P, JPt-P ) 4901
Hz). EI-MS: m/z 1098 (parent ion). Spectral data for 5 are as

4110 Organometallics, Vol. 27, No. 16, 2008
Adams and Trufan
follows. IR νCO (cm-1 in CH2Cl2): 2073 (vw), 2040 (w), 2004 (vs),
APEX CCD-based diffractometer using Mo KR radiation (λ )
0.710 73 Å). The raw data frames were integrated with the SAINT+
program by using a narrow-frame integration algorithm.12 Correc-
tion for Lorentz and polarization effects were also applied with
SAINT+. An empirical absorption correction based on the multiple
measurement of equivalent reflections was applied 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, using the SHELXTL software
package.13 All non-hydrogen atoms were refined with anisotropic
thermal parameters. Unless indicated otherwise, the hydrogen atoms
were placed in geometrically idealized positions and included as
standard riding atoms during the least-squares refinements. Crystal
data, data collection parameters, and results of the refinements are
given in Table 1.
1
1977 (w, sh), 1841 (m), 1815 (m). H NMR (CDCl3, in ppm): δ
7.30-7.91 (m, 10H, Ph), 1.59 (d, 27H, CH3, 3JP-H ) 13 Hz), 1.49
3
(d, 27H, CH3, JP-H ) 13 Hz). 31P{1H} NMR (in CD2Cl2, ppm):
1
1
δ 111.47 (s, 1P, JPt-P ) 5876 Hz), 108.26 (s, 1P, JPt-P ) 4849
Hz). Positive ion ES-MS: m/z 1495 (M + H, parent ion).
Reaction of Ru2(CO)8(µ-SnPh2) with
2
Equiv of
Pt(PBut3)2. A 9.1 mg (0.013 mmol) amount of Ru2(CO)8(µ-SnPh2)
was dissolved in 25 mL of methylene chloride in a 100 mL three-
neck flask. To this solution was added 17.6 mg (0.294 mmol) of
Pt(PBut3)2, and the mixture was stirred for 20 min at room
temperature in the dark. During this time, the pale yellow solution
turned red. The solvent was then removed, and the products were
separated by TLC by using a 6:1 hexane-methylene chloride
solvent mixture to give 13.2 mg of red 5 (68% yield).
Irradiation of 1 under 13CO. A 23.6 mg amount of 1 was
dissolved in 25 mL of benzene in a 100 mL three-neck flask. The
pale yellow solution was irradiated with a 100 W sunlamp for 35
min while a very slow purge of 13CO was applied. The reaction
mixture was cooled, and the solvent was removed in vacuo. The
products were separated by TLC by using a 6:1 hexane-methylene
chloride solvent mixture in the dark. This procedure gave 4.3 mg
of 1 and 1.3 mg of 2. Both products were then analyzed by mass
spectrometry, and both showed an enrichment in 13CO to ap-
proximately 25% of the total CO composition.
Compounds 1, 2, and 5 crystallized in the triclinic crystal system.
j
The space group P1 was assumed and confirmed by the successful
refinement and solution of the structure in each case. The asym-
metric crystal unit of 1 contains two independent formula equiva-
lents of the molecule. The hydrido ligands in 1 were located and
refined in the analysis. Compound 5 contains one formula equivalent
of the molecule in the asymmetric crystal unit and also one and a
half molecule of octane from the crystallization solvent that had
cocrystallized with the complex. The octane solvent molecule was
included in the analysis and was satisfactorily refined with isotropic
thermal parameters. The hydrogen atoms on this octane molecules
were omitted in these calculations. Compounds 3 and 4 both
crystallized in the monoclinic crystal system. The systematic
absences in the intensity data identified the space group uniquely
as P21/c in both cases. For compound 3 there is one formula
equivalent of the complex present in the asymmetric unit. One-
fourth of a methylene chloride molecule from the crystallization
solvent cocrystallized with the complex. It was satisfactorily refined
in the analysis. Compound 4 contains four independent formula
equivalents of the molecule in the asymmetric unit. All four
molecules were located and refined with anisotropic thermal
parameters for the non-hydrogen atoms. The carbon atoms on one
of the phenyl groups and a few of the tert-butyl carbon atoms
exhibited large thermal parameters, which was probably due to
minor disorder effects.
Molecular Orbital Calculations. All molecular orbital calcula-
tions reported herein were performed by using the Fenske-Hall
method.14 The calculations were performed utilizing a graphical
user interface developed15 to build inputs and view outputs from
standalone Fenske-Hall and MOPLOT2 binary executables.16
Contracted double-ꢀ basis sets were used for the Ru 4d, Pt 5d, Sn
5p, P 3p, and C and O 2p atomic orbitals. The Fenske-Hall scheme
is a nonempirical approximate method that is capable of calculating
molecular orbitals for very large transition-metal systems. For these
calculations, the input structures were obtained from the positional
parameters from the crystal structure analyses. The structures are
not optimized by these calculations. The tert-butyl groups on the
phosphine ligands and the phenyl groups on the SnPh2 ligand were
replaced with hydrogen: e.g., PH3 and SnH2.
Irradiation of 2 under 13CO. A 7.1 mg amount of 2 was
dissolved in 20 mL of benzene in a 100 mL three-neck flask. The
solution was stirred in the dark for 30 min under a 13CO atmosphere,
and careful IR monitoring showed no sign of change. Then, the
solution was irradiated with a 100 W sunlamp for 35 min. The
reaction was stopped, the solvent was removed in vacuo, and the
products were separated by TLC by using a 6:1 hexane-methylene
chloride solvent mixture in the dark. A 2.9 mg portion of the starting
material was recovered and was then analyzed by mass spectrom-
etry; it was found to have an enrichment in 13CO to approximately
10% of the total CO composition.
Reaction of 3 with CO. A 13.3 mg (0.012 mmol) amount of 3
was dissolved in 15 mL of benzene in a 100 mL three-neck flask
and stirred and irradiated with a 100 W sunlamp under a CO
atmosphere for 35 min. The solvent was then removed in vacuo,
and the products were separated by TLC by using a 6:1
hexane-methylene chloride solvent mixture to give 8.9 mg of 4
(65% yield).
Reaction of 4 with H2. A 6.3 mg amount (0.006 mmol) of 4
was dissolved in 14 mL of benzene in a 100 mL three-neck flask
and stirred and irradiated with a 100 W sun lamp under an H2
atmosphere for 40 min. The irradiation was then stopped and the
solvent removed in vacuo. The product 3 was then separated by
TLC by using a 6:1 hexane-methylene chloride solvent mixture
to give 1.3 mg (21% yield).
Reaction of 4 with Pt(PBut3)2. A 17.8 mg amount (0.0162
mmol) of Ru2(CO)8(µ-SnPh2)(µ-PtPBut3) was dissolved in 25 mL
of dichloromethane in a 100 mL three-neck flask and stirred for
60 min at room temperature. The solvent was then removed in
vacuo, and the products were separated by TLC by using a 6:1
hexane-methylene chloride solvent mixture to give 0.7 mg of
unreacted 4 and 20.7 mg (85% yield) of 5.
Crystallographic Analyses. Orange single crystals of 1-3
suitable for X-ray diffraction were obtained by slow evaporation
of solvent from solutions in hexane solvent at -80 °C. Orange
single crystals of 4 suitable for X-ray diffraction were obtained by
slowevaporationofsolventfromsolutionsinmethylenechloride-octane
solvent mixtures at -25 °C. Red single crystals of 5 suitable for
X-ray diffraction were obtained by slow evaporation of solvent from
solutions in methylene chloride-octane solvent mixtures at -25
°C. Each data crystal was glued onto the end of a thin glass fiber.
X-ray intensity data were measured by using a Bruker SMART
(12) SAINT+ Version 6.2a; Bruker Analytical X-ray Systems, Inc.,
Madison, WI, 2001.
(13) Sheldrick, G. M. SHELXTL Version 6.1; Bruker Analytical X-ray
Systems, Inc., Madison, WI, 1997.
(14) (a) Hall, M. B.; Fenske, R. F. Inorg. Chem. 1972, 11, 768–775.
(b) Webster, C. E.; Hall, M. B. In Theory and Applications of Computational
Chemistry: The First Forty Years; Dykstra, C., Ed.; Elsevier: Amsterdam,
2005; Chapter 40, pp 1143-1165.
(15) Manson, J.; Webster, C. E.; Hall, M. B. JIMP, development version
0.1.v117 (built for Windows PC and Redhat Linux); Department of
Chemistry, Texas A&M University, College Station, TX, 2004; http://
www.chem.tamu.edu/jimp/.
(16) Lichtenberger, D. L. MOPLOT2 for orbital and density plots from
linear combinations of Slater or Gaussian type orbitals, version 2.0;
Department of Chemistry, University of Arizona, Tucson, AZ, 1993.

Diruthenium-Tin Complexes
Organometallics, Vol. 27, No. 16, 2008 4111
Table 1. Crystallographic Data for Compounds 1-5
1
2
3
4
5
empirical formula
Ru2SnO8C20H12 Ru2SnO8C20H10 PtRu2SnPO7C31H39 · 1/4CH2Cl2 PtRu2SnPO8C24H37 Pt2Ru2SnP2O8C44H64 · 3/2C8H18
formula wt
cryst syst
lattice params
a (Å)
b (Å)
c (Å)
701.12
699.11
1091.74
1000.43
1665.24
triclinic
triclinic
triclinic
monoclinic
monoclinic
9.6227(5)
15.1915(7)
17.7393(8)
75.200(1)
75.721(1)
89.312(1)
2426.1(2)
8.2765(4)
9.3170(5)
16.1426(9)
87.377(1)
75.261(1)
75.544(1)
1147.7(1)
16.9915(5)
11.7343(3)
19.2385(6)
90.00
99.409(1)
90.00
3784.23(19)
P21/c (No. 14)
4
27.138(2)
17.0066(14)
32.635(3)
90.00
94.656(2)
90.00
15012(2)
P21/c (No. 14)
16
13.8149(6)
15.2333(7)
17.0571(8)
65.136(1)
84.937(1)
70.122(1)
3056.5(2)
R (deg)
ꢁ (deg)
γ (deg)
V (Å3)
j
j
j
space group
Z
P1 (No. 2)
2
P1 (No. 2)
2
P1 (No. 2)
2
Fcalcd (g/cm3)
µ(Mo KR) (mm-1
temp (K)
2θmax (deg)
1.920
2.290
293(2)
56.82
2.023
2.420
293(2)
56.52
4796
280
1.916
5.238
294(2)
49.66
6013
418
2.213
6.549
294(2)
57.70
20 028
1657
1.809
5.547
150(2)
56.64
13 486
598
)
no. of obsd rflns (I > 2σ(I)) 9029
no. of params
575
goodness of fit GOFa
max shift in cycle
residuals:a R1, wR2
abs cor, max/min
1.039
0.003
1.206
0.004
1.079
0.001
1.009
0.014
1.038
0.018
0.0424, 0.1104 0.0277, 0.0889 0.0376, 0.0877
0.0531, 0.1113
multi-scan,
1.000/0.398
2.600
0.0307, 0.0768
multi-scan,
1.000/0.728
2.720
multi-scan,
1.000/0.804
1.385
multi-scan,
1.000/0.773
0.732
multi-scan,
1.000/0.744
1.362
largest peak in final
diff map (e/Å3)
a R1 ) ∑hkl(||Fo| - |Fc||)/∑hkl|Fo|; wR2 ) [∑hklw(|Fo| - |Fc|)2/∑hklwFo2 1/2, w ) 1/σ2(Fo); GOF ) [∑hklw(|Fo| - |Fc|)2/(ndata - nvari)]1/2
] .
and Ru(2)-Sn(1) ) 2.7335(6) Å for molecule 1 and Ru(3)-Sn(3)
) 2.7260(6) Å and Ru(4)-Sn(3) ) 2.7219(6) Å for molecule
2. The four CO ligands and the tin atom are arranged in the
form of a square pyramid. The sixth ligand on each ruthenium
atom is a hydrido ligand that lies trans to the CO ligand in the
apex of the square pyramid. The hydrido ligands were located
and refined in the structural analysis: Ru(1)-H(1) ) 1.87(4)
Å, Ru(2)-H(2) ) 1.57(6) Å, Ru(3)-H(3) ) 1.93(4) Å, and
Ru(4)-H(4) ) 1.35(6) Å; however, the Ru-H distances span
a considerable range, because the hydrido ligands were not
located with high precision. The estimated standard deviations
are large, because it is difficult to locate hydrogen atoms
accurately in the proximity of heavy atoms such as ruthenium.
The hydrido ligands exhibit a single high-field resonance at δ
-7.63 in the 1H NMR spectrum. The Ru-H and Ru-Sn bond
distances are very similar to those observed for the compound
Ru(CO)4(SnPh3)H (6), Ru-H ) 1.63(4) Å and Ru-Sn )
2.7108(3) Å, which we recently obtained from the reaction of
Ph3SnH with Ru(CO)5.9
Figure 1. ORTEP diagram of the molecular structure of 1 showing
40% probability thermal ellipsoids. Selected bond distances (Å)
and angles (deg) are as follows: molecule 1, Ru(1)-Sn(1) )
2.7206(5), Ru(2)-Sn(1) ) 2.7335(6), Ru(1)-H(1) ) 1.87(4),
Ru(2)-H(2) ) 1.57(6); Ru(1)-Sn(1)-Ru(2) ) 115.666(18);
molecule 2, Ru(3)-Sn(3) ) 2.7260(6), Ru(4)-Sn(3) ) 2.7219(6),
Ru(3)-H(3) ) 1.93(4), Ru(4)-H(4) ) 1.35(6); Ru(3)-Sn(2)-Ru(4)
) 115.866(19).
When compound 1 was irradiated with visible radiation for
35 min under a CO atmosphere, the new compound Ru2(CO)8(µ-
SnPh2) (2) was formed and isolated in 51% yield. Compound 2
1
was characterized by IR, H NMR, and mass spectra and by a
single -crystal X-ray diffraction analysis. An ORTEP diagram
of the molecular structure of 2 is shown in Figure 2. The
molecule contains two Ru(CO)4 groups that are joined by a
Ru-Ru single bond, Ru(1)-Ru(2) ) 3.0035(6) Å, and a
bridging SnPh2 ligand. The Ru-Ru bond distance is slightly
longer than the Ru-Ru bond distance in Ru3(CO)12, 2.854(1)
Å.17 The Ru-Sn bond distances are slightly shorter than those
in 1, Ru(1)-Sn(1) ) 2.6596(5) Å, Ru(2)-Sn(1) ) 2.6655(5)
Å, Ru(1)-Sn(1)-Ru(2) ) 68.671(15)°. Although the ruthenium
atoms in compounds 1 and 2 obey the 18-electron rule, a
Fenske-Hall (FH) molecular orbital analysis of 2 was per-
formed in order to develop a more detailed view of its
metal-metal bonding in order to compare with the bonding of
Results
The compound [Ru(CO)4H]2(µ-SnPh2) (1) was obtained in
57% yield from the reaction of Ph2SnH2 with Ru(CO)5 in hexane
solvent when heated to reflux for 30 min. Compound 1 was
characterized by IR, 1H NMR, and mass spectra and by a single-
crystal X-ray diffraction analysis. There are two crystallographi-
cally independent molecules in the asymmetric crystal unit of
1. Both molecules are structurally similar. An ORTEP diagram
of the molecular structure of one of the two independent
molecules is shown in Figure 1. The molecule consists of two
HRu(CO)4 groups that are held together by a bridging SnPh2
ligand. There is no bond between the ruthenium atoms:
Ru(1) · · · Ru(2) ) 4.167(1) Å for molecule 1 and Ru(3) · · · Ru(4)
) 4.167(1) Å for molecule 2. The Ru-Sn bond distances are
typical of Ru-Sn single bonds: Ru(1)-Sn(1) ) 2.7206(5) Å
(17) Churchill, M. R.; Hollander, F. J.; Hutchinson, J. P. Inorg. Chem.
1977, 16, 2655.

4112 Organometallics, Vol. 27, No. 16, 2008
Adams and Trufan
Figure 4. ORTEP diagram of the molecular structure of 3 showing
30% probability thermal ellipsoids. Selected interatomic bond
distances (Å) and angles (deg) are as follows: Ru(1)-Ru(2) )
2.9782(8), Pt(1)-Ru(2) ) 2.7504(6), Pt(1)-Ru(1) ) 2.9404(6),
Ru(1)-Sn(1) ) 2.6557(8), Ru(2)-Sn(1) ) 2.6488(8), Ru(1)-H(1)
) 2.09(5), Ru(1)-H(2) ) 1.97(7), Ru(2)-H(2) ) 1.60(7),
Pt(1)-H(1))1.37(5),Pt(1)-P(1))2.3788(17);Ru(1)-Sn(1)-Ru(2)
) 68.31(2), Ru(1)-Pt(1)-Ru(2) ) 63.009(18), Sn(1)-Ru(1)-Pt(1)
) 71.769(18), Sn(1)-Ru(2)-Pt(1) ) 75.012(19).
Figure 2. ORTEP diagram of the molecular structure of 2,showing
30% probability thermal ellipsoids. The hydrogen atoms are omitted
for clarity. Selected interatomic bond distances (Å) and angles (deg)
are as follows: Ru(1)-Ru(2) ) 3.0035(6), Ru(1)-Sn(1) ) 2.6596(5),
Ru(2)-Sn(1) ) 2.6655(5); Ru(1)-Sn(1)-Ru(2) ) 68.671(15).
Pd(PBut3)2 toward the insertion of PhC2H into their M-H bonds.
The nature of the activation was shown by the compound
PtOs(CO)4(SnPh3)(PBut3)(µ-H), which was isolated from the
reaction of Os(CO)4(SnPh3)H with Pt(PBut3)2 and structurally
characterized. The compound PtOs(CO)4(SnPh3)(PBut3)(µ-H)
was found to possess a hydrido ligand bridging a Pt-Os bond.
Accordingly, it was decided to investigate the reaction of 1 with
Pt(PBut3)2. Compound 1 reacted with Pt(PBut3)2 at room
temperature to give the orange product Ru2(CO)7(µ-SnPh2)(µ-
H)2(µ-PtPBut3) (3) in 76% yield in 10 min. Compound 3 was
1
characterized by IR, H and 31P NMR, and mass spectra and
by a single-crystal X-ray diffraction analysis. An ORTEP
diagram of the molecular structure of 3 is shown in Figure 4.
The molecule contains two Ru(CO)3 groups that are joined by
a hydride-bridged Ru-Ru single bond: Ru(1)-Ru(2) ) 2.9782(8)
Å. The Ru-Ru bond is also bridged by a Pt(CO)(PBut3) group.
The Pt-Ru bond distances are significantly different in length:
Pt(1)-Ru(2) ) 2.7504(6) Å and Pt(1)-Ru(1) ) 2.9404(6) Å.
The longer length of the Pt(1)-Ru(1) bond can be attributed to
the presence of the bridging hydrido ligand H(1).19 There is
also a SnPh2 ligand bridging the Ru-Ru bond. The Ru-Sn
bond distances are very similar to those in 2: Ru(1)-Sn(1) )
2.6557(8) Å and Ru(2)-Sn(1) ) 2.6488(8) Å. There is a second
hydrido ligand, H(2), which bridges the Ru-Ru bond. The two
hydrido ligands are inequivalent and exhibit separate high-field
resonances in the 1H NMR spectrum,: δ -11.63 (H2) and
-12.44 (H1). The latter exhibits significant coupling to the
Figure 3. Contour diagrams for the metal-metal bonding molecular
orbitals in 2: A1 HOMO, B1 HOMO-1, A1 HOMO-2, and B1
LUMO.
its platinum adducts that are described below. The molecular
symmetry of 2 is C2V. Contour diagrams of the three highest
occupied molecular orbitals (HOMOs) of 2 are shown in Figure
3. The A1 HOMO lies at -7.07 eV, which is predominantly
the Ru-Ru bonding orbital. The Ru-Sn bonds are represented
by the B1 HOMO-1 at -8.37 eV and the A1 HOMO-2 at -9.00
eV. Their lower energies suggest that the Ru-Sn bonds are
stronger than the Ru-Ru bond. The antisymmetric B1 LUMO
in 2 is clearly Ru-Ru antibonding. The importance of M-Sn
bonding to bridging SnPh2 ligands was also observed for the
related compounds Rh3(CO)6(SnPh3)3(µ-SnPh2)33 and Re2(CO)8(µ-
SnPh2)2.18
3
closely positioned phosphorus atom, JP-H ) 13 Hz.
To develop an understanding of the metal-metal bonding in
3, a Fenske-Hall (FH) molecular orbital analysis was per-
formed. The contour diagrams of the most important cluster
bonding molecular orbitals (HOMOs) are shown in Figure 5.
The delocalized bonding of the platinum atom to the two
ruthenium atoms is nicely illustrated by the HOMO, which lies
at -6.56 eV. The bonding of the tin atom to the two ruthenium
In previous work it was shown that the compounds
M(CO)4(SnPh3)H (M ) Ru, Os) are activated by Pt(PBut3)2 and
(18) (a) Adamas, R. D.; Captain, B.; Herber, R. H.; Johansson, M.;
Nowik, I.; Smith, J. L., Jr.; Smith, M. D. Inorg. Chem. 2005, 44, 6346–
6358. (b) Adams, R. D.; Captain, B.; Johansson, M.; Smith, J. L. J. Am.
Chem. Soc. 2005, 127, 488–489.
(19) (a) Bau, R.; Drabnis, M. H. Inorg. Chim. Acta 1997, 259, 27–50.
(b) Teller, R. G.; Bau, R. Struct. Bonding 1981, 41, 1–82.

Diruthenium-Tin Complexes
Organometallics, Vol. 27, No. 16, 2008 4113
Figure 6. ORTEP diagram of the molecular structure of 4 showing
30% probability thermal ellipsoids. The hydrogen atoms are omitted
for clarity. Selected interatomic bond distances (in Å) each of the
four independent molecules in the unit cell are as follows:
Ru(1)-Ru(2) ) 3.0179(10), 3.0168(9), 3.0130(9), 3.0143(10);
Ru(1)-Sn(1) ) 2.6564(9), 2.6585(9), 2.6586(9), 2.6564(9);
Ru(2)-Sn(1) ) 2.6533(9), 2.6637(10), 2.6596(9), 2.6588(10);
Ru(1)-Pt(1) ) 2.7672(8), 2.7750(7), 2.7426(7), 2.7813(8);
Ru(2)-Pt(1) ) 2.7681(8), 2.7535(8), 2.7838(7), 2.7683(8);
Pt(1)-P(1) ) 2.353(2), 2.350(2), 2.347(2), 2.367(2).
Figure 5. Contour diagrams for the molecular orbitals representing
the metal-metal bonding in 3, HOMO, HOMO-1, and A1 HOMO-
2, and those of the bridging hydrido ligands, HOMO-13 and
HOMO-15.
atoms is shown by the symmetric HOMO-2 at -9.22 eV and
the antisymmetric HOMO-1 at -7.40 eV. The orbitals involving
the bridging hydrido ligands lie at much lower energies. The
bonding of the H(1) bridging ligand is shown by the HOMO-
15 at -14.71 eV, and the bonding of H(2) to the two ruthenium
atoms is shown by the HOMO-13 at -12.96 eV.
It has been shown that the Pt(PBut3) group can be added both
to Ru-Sn bonds7 and to Ru-Ru bonds.20 Since compound 2
contains both types of these bonds, it was decided to investigate
its reaction of Pt(PBut3)2 to try to ascertain if it would be possible
to identify any preference for the attachment of the Pt(PBut3)
group to these two types of bonds. Two products, PtRu2(CO)8)-
(PBut3)(µ-SnPh2) (4; 78% yield) and Pt2Ru2(CO)8)(PBut3)2(µ-
SnPh2) (5; 15% yield), were obtained from the reaction of 2
with Pt(PBut3)2 at room temperature after 70 min. The yield of
5 was increased to 68% when 2 equiv of Pt(PBut3)2 was used
in the reaction, and when 4 was treated with an additional
quantity of Pt(PBut3)2, it was converted to 5 in 85% yield.
Compounds 4 and 5 were both characterized by IR, 1H and 31
P
NMR, and mass spectra and by single-crystal X-ray diffraction
analyses.
Figure 7. Contour diagrams of the FH molecular orbitals in 4 that
show the metal-metal bonding.
There are four independent molecules in the asymmetric
crystal unit of 4. All four molecules are structurally similar.
An ORTEP diagram of one of these four molecules is shown
in Figure 6. The molecule is very similar to 2, except that it
contains a Pt(PBut3) group that has been added across the
Ru-Ru bond. The Ru-Ru bond distances in 4, Ru(1)-Ru(2)
) 3.0179(10), 3.0168(9), 3.0130(9), 3.0143(10) Å (average
3.0155 Å), are slightly longer than the Ru-Ru distance in 2,
3.0035(6) Å. The Ru-Sn bond distances in 4 are not signifi-
cantly different from those in 2: Ru(1)-Sn(1) ) 2.6564(9),
2.6585(9), 2.6586(9), 2.6564(9) Å and Ru(2)-Sn(1) ) 2.6533(9),
2.6637(10), 2.6596(9), 2.6588(10) Å. There is a bridging
carbonyl ligand across each Ru-Pt bond. The Ru-Pt bond
distances, Ru(1)-Pt(1) ) 2.7672(8), 2.7750(7), 2.7426(7),
2.7813(8) Å; and Ru(2)-Pt(1) ) 2.7681(8), 2.7535(8), 2.7838(7),
2.7683(8) Å (average 2.7675 Å), are slightly shorter than those
found for the compound Ru3(CO)12[Pt(PBut3)]3 (6), Ru-Pt (av)
) 2.807(1) Å,20 which has a bridging Pt(PBut3) on each Ru-Ru
bond, but in compound 6 only three of the six Ru-Pt distances
contain a bridging CO ligand.
To understand the metal-metal bonding in 4, a Fenske-Hall
molecular orbital analysis was performed. Contour diagrams of
five selected molecular orbitals in 4 are shown in Figure 7. The
HOMO at -7.02 eV exhibits delocalized bonding between the
platinum atom and the two ruthenium atoms. This orbital clearly
shows how the Pt(PBut3) group interacts with the HOMO of 2.
This explains the preference of the Pt(PBut3) group for addition
to the Ru-Ru bond. The bonding between the ruthenium atoms
and the bridging tin atom is shown by the antisymmetric
HOMO-3 at -8.96 eV and the symmetric HOMO-13 at -12.29
eV. Significant interactions between the platinum atom and the
two ruthenium atoms are shown by the symmetric HOMO-12
at -11.59 eV and the antisymmetric HOMO-11 at -11.42 eV.
In the presence of mild irradiation, compound 4 reacts with
hydrogen by loss of CO to form 3, but the yield is not high,
21%.
An ORTEP diagram of the molecular structure of 5 is shown
in Figure 8. The molecule is very similar to 4 except that it
contains a second Pt(PBut3) group that was added across one
of the Ru-Sn bonds of 4. In contrast to 4, the Ru-Ru bond
(20) Adams, R. D.; Boswell, E. M.; Captain, B.; Zhu, L. J. Cluster Sci.
2008, 19, 121–132.

4114 Organometallics, Vol. 27, No. 16, 2008
Adams and Trufan
Figure 8. ORTEP diagram of the molecular structure of 5 showing
50% probability thermal ellipsoids. The hydrogen atoms are omitted
for clarity. Selected interatomic bond distances (in Å) and angles
(deg) are as follows: Ru(1)-Ru(2) ) 2.9878(4), Ru(1)-Sn(1) )
2.6810(4), Ru(2)-Sn(1) ) 2.6871(4), Ru(1)-Pt(1) ) 2.7232(4),
Ru(1)-Pt(2) ) 2.7236(3), Ru(2)-Pt(1) ) 2.7683(4), Pt(2)-Sn(1)
) 2.8768(3), Pt(1)-P(1) ) 2.3532(12), Pt(2)-P(2) ) 2.3031(10);
Ru(1)-Sn(1)-Pt(2) ) 58.562(9), Ru(2)-Sn(1)-Pt(2) ) 125.755(12),
Figure 9. Contour diagrams of the FH molecular orbitals in 5 that
show the metal-metal bonding.
Scheme 1
Ru(1)-Sn(1)-Ru(2)
) 67.639(11), Pt(1)-Ru(1)-Pt(2) )
166.598(14).
distance in 5, Ru(1)-Ru(2) ) 2.9877(5) Å, is slightly shorter
than that in 2. These differences in the Ru-Ru bond distances
are very small and are probably of no chemical significance.
The added Pt(PBut3) group bridges the Ru(1)-Sn(1) bond.
Interestingly, the Ru(1)-Sn(1) bond is only very slightly shorter
than the Ru(2)-Sn(1) bond: 2.6809(5) Å versus 2.6872(5) Å.
Each Ru-Pt bond contains a bridging CO ligand. The two
Ru-Pt bonds to Ru(1) are essentially equal in length: Ru(1)-Pt(1)
) 2.7232(4) Å and Ru(1)-Pt(2) ) 2.7236(3) Å. The Ru-Pt
bond to Ru(2) is significantly longer than those to Ru(1):
Ru(2)-Pt(1) ) 2.7683(4) Å. The tin atom is pentavalent, and
the Pt-Sn bond is long and presumably very weak. The Pt-Sn
bond distance, 2.8768(3) Å, is significantly longer than the
Ru(1)-Pt(2) bond distance and the Pt-Sn distances in the
compounds Pt(H)(SnPh3)(PPh3)2 (Pt-Sn ) 2.564(1) Å)21 and
Os3(CO)9[Pt(Ph)(PPh3)2](µ-SnPh2)2(µ3-SnPh) (Pt-Sn ) 2.6298(6)
Å),5 where the tin atom has the usual tetravalency. It is even
longer than the Pt-Sn bond distances, 2.74-2.80 Å, found for
Pt(PBut3)-bridged Ru-Sn bonds in the series of compounds
Ru3Sn3Ptn (n ) 1-3), where the tin atom exhibits a similar
pentavalency.7
with a very weak Pt-Sn interaction, as indicated by the long
Pt-Sn bond distance (see above).
Discussion
To develop a view of the metal-metal bonding in 5, its FH
molecular orbitals were calculated.15 The bulk of the metal-metal
bonding in 5 is shown by the HOMO, HOMO-4, HOMO-13,
and HOMO-18. These four orbitals are shown in Figure 9. The
HOMO at -6.76 eV contains a large contour similar to that
found in 4 that is delocalized across the platinum atom Pt(1)
and the two ruthenium atoms. The HOMO-4 at -8.72 eV shows
the bond between Pt(2) and Ru(1). The Ru-Sn bonding is
revealed by HOMO-18 at -11.99 eV. The only orbital that
exhibits any significant bonding interaction between Pt(2) and
the tin atom is the HOMO-13 at -10.32 eV. The tin contribution
to this orbital is relatively small and comes from the tin 5px
orbital (8.2%) and 5py orbital (5.9%). This analysis is consistent
A summary of the reactions described in this report is shown
in Scheme 1.
We have found that Ph2SnH2 reacts with 2 equiv of Ru(CO)5
with the loss of CO and two oxidative addition steps to form
the product 1. In previous studies we found that Ru(CO)5 reacts
with Ph3SnH by loss of a CO ligand and oxidative addition of
the Sn-H bond to the ruthenium atom to form the compound
Ru(CO)4(SnPh3)H (6).9 It seems likely that the formation of 1
is preceded by a product such as Ru(CO)4(SnPh2H)H, formed
by the addition of 1 equiv of Ru(CO)5 to Ph2SnH2, but this
compound was not observed under our conditions. When
irradiated, compound 1 eliminates H2 to form compound 2. The
formation of H2 was confirmed by 1H NMR spectroscopy. The
yield of 2 was increased when this reaction was performed under
a CO atmosphere. To try to ascertain some information about
(21) Latif, L. A.; Eaborn, C.; Pidcock, A.; Ng, S. W. J. Organomet.
Chem. 1994, 474, 217.

Diruthenium-Tin Complexes
Scheme 2
Organometallics, Vol. 27, No. 16, 2008 4115
the Ru-Ru bond is explained by the molecular orbital structure
in 2: that is, the most energetically accessible bond is the Ru-Ru
bond, the HOMO. The Ru-Sn bonds are the next most
available, HOMO-1 and HOMO-2 (see Figure 3).
Summary
the mechanism of this reaction, we performed the irradiation
of 1 under an atmosphere of 13CO. We observed that 13CO was
incorporated significantly (on the average 20%) both in 2 and
in the starting material 1. We also found that 13CO is readily
incorporated into 2 when it is irradiated under an atmosphere
of 13CO, but we found no evidence for the formation of 1 from
2 in attempts to add H2 to 2 under irradiation. This latter
experiment indicates that the incorporation of 13CO into 1 does
not proceed through the intermediacy of 2. On the basis of these
results, the following mechanism for H2 elimination from 1 to
form 2 is proposed (see Scheme 2). In the first step a CO ligand
is eliminated from one of the ruthenium atoms to give the
intermediate A, which contains a vacant ligand site on one of
the ruthenium atoms. This step is reversible and would thus
explain the incorporation of 13CO into 1 when the transformation
is performed under a 13CO atmosphere. In the second step, the
Ru(CO)4H group in A is then oxidatively added to the
unsaturated Ru(CO)3H group to form the intermediate B. A
Ru-Ru bond would be formed at this time, and one or both of
the hydride ligands could assume a position bridging the Ru-Ru
bond. In the final step, CO is readded to the intermediate B
and the product 2 is formed as the H2 is eliminated. This step
explains why the yield of 2 was higher when the reaction was
preformed under a CO atmosphere. The addition of CO to B is
very similar to the known reaction of Os3(CO)11(µ-H)H with
CO to yield Os3(CO)12 and H2.22 This mechanism is similar to
the binuclear reductive elimination mechanism proposed by
Norton for the elimination of H2 from Os(CO)4H2 to yield the
diosmium complex Os2(CO)8H2.23
In this work, the reactivity of Sn-H bonds with Ru(CO)5
has been demonstrated through the reactions of the compound
Ph2SnH2. It has been shown that both SnH bonds in Ph2SnH2
participate in the reaction to form the compound 1, which then
eliminates H2 to form the SnPh2-bridged diruthenium compound
2. In addition, the ability of Pt(PBut3)2 to form heterometallic
compounds containing tin has been further demonstrated.
Compound 1 also reacts with Pt(PBut3)2 to form the trimetallic
complex 3 by loss of CO. Compound 2 reacts with Pt(PBut3)2
to form the Pt(PBut3) adduct 4 by adding a Pt(PBut3) group to
the Ru-Ru bond, and compound 4 reacts with Pt(PBut3)2 to
form the Pt(PBut3) adduct 5 by adding a Pt(PBut3) group
bridging one of its Ru-Sn bonds. Compound 4 reacts with
hydrogen by loss of CO to form 3.
As we have recently shown for related compounds, it is
anticipated that these new heterometallic complexes will be able
to serve as precursors to new nanoscale heterogeneous hydro-
genation catalysts when deposited and activated on suitable
supports.2,7,24
Acknowledgment. This research was supported by the
National Science Foundation under Grant No. CHE-0743190.
This report is dedicated to the memory of Professor F. Albert
Cotton.
Supporting Information Available: CIF files for each of the
structural analyses. This material is available free of charge via
the Internet at http://pubs.acs.org.
The products formed by the addition of the Pt(PBut3) group
to the metal-metal bonds of 2 shows that the Ru-Ru bond is
preferred over the Ru-Sn bonds but that both bonds are
amenable to Pt(PBut3) addition. The preference for addition to
OM800385W
(24) (a) Thomas, J. M.; Adams, R. D.; Boswell, E. M.; Captain, B.;
Gro¨nbeck, H.; Raja, R. Faraday Discuss. 2008, 138, 301–315. (b) Adams,
R. D.; Boswell, E. M.; Captain, B.; Hungria, A. B.; Midgley, P. A.; Raja,
R.; Thomas, J. M. Angew. Chem., Int. Ed. 2007, 46, 8182–8185. (c) 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, 45, 4782–
4785.
(22) Deeming, A. J.; Hasso, S. J. Organomet. Chem. 1976, 114, 313–
324.
(23) Norton, J. R. Acc. Chem. Res. 1979, 12, 139–145.