Heterolytic cleavage of dihydrogen promoted by sulfido-bridged tungsten-ruthenium dinuclear complexes

Article abstract of DOI:10.1021/ja029941x

A series of sulfido-bridged tungsten-ruthenium dinuclear complexes Cp*W(μ-S)₃RuX(PPh₃)₂ (4a; X = Cl, 4b; X = H), Cp*W(O)(μ-S)₂RuX(PPh₃)₂ (5a; X = Cl, 5b; X = H), and Cp*W(NPh)(μ-S)₂RuX-(PPh₃)₂ (6a; X = Cl, 6b; X = H) have been synthesized by the reactions of (PPh₄)[Cp*W(S)₃] (1), (PPh₄)-[Cp*W(O)(S)₂] (2), and (PPh₄)[Cp*W(NPh)(S)₂] (3), with RuClX(PPh₃)₃ (X = Cl, H). The heterolytic cleavage of H₂ was found to proceed at room temperature upon treating 5a and 6a with NaBAr^F₄ (Ar^F = 3, 5-C₆H₃-(CF₃)₂) under atmospheric pressure of H₂, which gave rise to [Cp*W(OH)(μ-S)₂RuH(PPh₃)₂] (BAr^F₄) (7a) and [Cp*W(NHPh)(μ-S)₂RuH(PPh₃)₂] (BAr^F₄) (8), respectively. When Cp*W(O)(μ-S)₂Ru(PPh₃)₂H (5b) was treated with a Bronstead acid, [H(OEt₂)₂](BAr^F₄) or HOTf, protonation occurred exclusively at the terminal oxide to give [Cp*W(OH)(μ-S)₂RuH(PPh₃)₂](X) (7a; X = BAr^F₄, 7b; X = OTf), while the hydride remained intact. The analogous reaction of Cp*W(μ-S)₃Ru(PPh₃)₂H (4b) led to immediate evolution of H₂. Selective deprotonation of the hydroxyl group of 7a or 7b was induced by NEt₃ and 4b, generating Cp*W(O)(μ-S)₂Ru(PPh₃)₂H (5b). Evolution of H₂ was also observed for the reactions of 7a or 7b with CH₃CN to give [Cp*W(O)(μ-S)₂Ru(CH₃CN) (PPh₃)₂](X) (11a; X = BAr^F₄, 11b; X = OTf). We examined the H/D exchange reactions of 4b, 5b, and 7a with D₂ and CH₃OD, and found that facile H/D scrambling over the W-OH and Ru-H sites occurred for 7a. Based on these experimental results, the mechanism of the heterolytic H₂ activation and the reverse H₂ evolution reactions are discussed.

Full text of DOI:10.1021/ja029941x

Published on Web 06/07/2003
Heterolytic Cleavage of Dihydrogen Promoted by
Sulfido-Bridged Tungsten-Ruthenium Dinuclear Complexes
†
Yasuhiro Ohki, Nobuo Matsuura, Tadashi Marumoto, Hiroyuki Kawaguchi, and
Kazuyuki Tatsumi*
Contribution from the Department of Chemistry, Graduate School of Science and Research
Center for Materials Science, Nagoya UniVersity, Furo-cho, Chikusa-ku,
Nagoya 464-8602, Japan
Received December 27, 2002; E-mail: i45100a@nucc.cc.nagoya-u.ac.jp
Abstract: A series of sulfido-bridged tungsten-ruthenium dinuclear complexes Cp*W(µ-S)
3
RuX(PPh
(5a; X ) Cl, 5b; X ) H), and Cp*W(NPh)(µ-S) RuX-
(6a; X ) Cl, 6b; X ) H) have been synthesized by the reactions of (PPh )[Cp*W(S) ] (1), (PPh )-
] (2), and (PPh )[Cp*W(NPh)(S) ] (3), with RuClX(PPh
was found to proceed at room temperature upon treating 5a and 6a with NaBAr
) under atmospheric pressure of H , which gave rise to [Cp*W(OH)(µ-S)
and [Cp*W(NHPh)(µ-S) RuH(PPh ) (8), respectively. When Cp*W(O)(µ-S)
](BArF
treated with a Brφnstead acid, [H(OEt ) or HOTf, protonation occurred exclusively at the terminal
](BArF
oxide to give [Cp*W(OH)(µ-S) RuH(PPh , 7b; X ) OTf), while the hydride remained
](X) (7a; X ) BArF
intact. The analogous reaction of Cp*W(µ-S) Ru(PPh H (4b) led to immediate evolution of H . Selective
deprotonation of the hydroxyl group of 7a or 7b was induced by NEt and 4b, generating Cp*W(O)(µ-
S) Ru(PPh H (5b). Evolution of H was also observed for the reactions of 7a or 7b with CH CN to give
Cp*W(O)(µ-S) Ru(CH CN)(PPh , 11b; X ) OTf). We examined the H/D exchange
](X) (11a; X ) BArF
reactions of 4b, 5b, and 7a with D and CH OD, and found that facile H/D scrambling over the W-OH and
Ru-H sites occurred for 7a. Based on these experimental results, the mechanism of the heterolytic H
activation and the reverse H evolution reactions are discussed.
3 2
)
(
(
4a; X ) Cl, 4b; X ) H), Cp*W(O)(µ-S)
PPh
2
RuX(PPh
3
)
2
2
3
)
2
4
3
4
[
Cp*W(O)(S)
of H
CF
2
4
2
)
3 3
(X ) Cl, H). The heterolytic cleavage
F
F
2
4
(Ar ) 3, 5-C
6
3
H -
F
(
3
)
2
2
2
RuH(PPh
)
3 2
](BAr
4
) (7a)
H (5b) was
2
)
3 2
4
2
Ru(PPh
3
)
2
)
2 2
4
2
)
3 2
4
3
)
3 2
2
3
2
3
)
2
2
3
[
2
3
)
3 2
4
2
3
2
2
5
1
Introduction
N-donor group, [(η :η -C H (CH ) NMe )Ru(dppm)](BF ), ac-
5
4
2 3
2
4
5
1
tivates H2 (60 atm) to afford [(η :η -C5H4(CH2)3NHMe2)RuH-
(dppm)](BF4), presumably via coordination of H2 at Ru and the
subsequent intramolecular deprotonation. Dihydrogen is re-
versibly added to the TidS bond of a titanocene sulfido complex
Cp*2TiS(py), generating Cp*2Ti(H)(SH).
dinuclear complexes are also capable of promoting heterolytic
Activation of molecular hydrogen is one of the fundamentally
important reactions in organometallic chemistry, and homolytic
1
4
c
cleavage of the H-H bond to give two hydrides can be achieved
via oxidative addition reactions on electron-rich transition
metals. However, the splitting of dihydrogen into a hydride and
a proton is less common. Heterolytic H-H cleavage has been
found to occur on mononuclear complexes in two ways; (1)
5
b,c
Some S-bridged
6
H2 cleavage. An early example is a cationic Rh2 complex [{Rh-
2
+
2
(triphos)}2(µ-S)2] (triphos ) tris(diphenylphosphinomethyl)
deprotonation of η -coordinated H2 with external or internal
2+
bases,2-4 and (2) addition of H2 to M-E bonds (E ) N, O, S)
ethane), which is converted to [{RhH(triphos)}2(µ-SH)2] by
5
to generate M-H and E-H bonds. For instance, the acidic
dihydrogen in [Cp*Re(CO)(NO)(H2)] can be deprotonated by
diethyl ether,3b and the ruthenium complex with a tethered
(
3) (a) Chinn, M. S.; Heinekey, D. M. J. Am. Chem. Soc. 1987, 109, 5865. (b)
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+
†
Present address: Coordination Chemistry Laboratory, Institute for
Molecular Science, Myodaiji, Okazaki, 444-8595, Japan.
(
1) (a) Kristj a´ nsd o´ ttir, S. S.; Norton, J. R. In Transition Metal Hydrides: Recent
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1
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(
c) Kubas, G. J. In Metal Dihydrogen and σ-Bond Complexes; Kluwer
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2
001.
(
2) (a) Kristj a´ nsd o´ ttir, S. S.; Moody, A. E.; Weberg, R. T.; Norton, J. R.
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7978
9
J. AM. CHEM. SOC. 2003, 125, 7978-7988
10.1021/ja029941x CCC: $25.00 © 2003 American Chemical Society

Heterolytic Cleavage of Dihydrogen
A R T I C L E S
the reaction with H2.6b Later, a neutral Ir2 complex [Ir(PPh3)2]2-
Scheme 1
(µ-S)2 was shown to react with two equiv of H2, via homolytic
and subsequent heterolytic pathways, and to eventually produce
6
c
[
[
IrH(PPh3)2]2(µ-H)(µ-S)(µ-SH). More recently, the reaction of
+
Cp2W(µ-S)2Ir(PPh3)2] with H2 (10 atm) was reported to give
three products, one of which was characterized as [Cp2W(µ-
+
31
6d
SH)2Ir(H)2(PPh3)2] based on the P NMR spectra.
The heterolytic cleavage of H2 has also been regarded as a
key step in the metalloenzymatic reactions of hydrogenases, the
active sites of which consist of the sulfur-bridged Fe/Fe and
7
Fe/Ni dinuclear centers. To provide a clue to understand the
reversible processes of biological H2 activation, it is desirable
to propose model reactions of the heterolytic H2 activation on
8
dinuclear metal centers, in addition to build the structural
9
models of the active sites. Soluble transition metal sulfido
clusters are attractive candidates for the investigation of the
mechanism of H2 activation. However, the construction of
appropriate sulfur-bridged dinuclear systems which are reactive
toward molecular hydrogen remains difficult, since dinucleation
reactions often give rise to less reactive products. One of the
effective ways to link two different metal centers by sulfur atoms
is to use transition metal sulfido complexes as precursors. We
have previously synthesized a series of tungsten thio complexes
such as (PPh4)[Cp*W(S)3] (1), (PPh4)[Cp*W(O)(S)2] (2), and
Aiming to obtain reactive dinuclear sulfido complexes, the
half-sandwich thio complexes of tungsten were combined with
appropriate ruthenium complexes. Having both electron-rich and
electron-deficient metal centers linked by sulfur atoms within
a molecule, the W-Ru complexes might be anticipated to
promote a new type of H2 activation. Thus, (PPh4)[Cp*W(S)3]
(1), (PPh4)[Cp*W(O)(S)2] (2), and (PPh4)[Cp*W(NPh)(S)2] (3)
1
0
(
PPh4)[Cp*W(O)(S)(Se)], and have demonstrated that they
were used as building blocks and reacted with RuCl2(PPh3)3
and RuCl(H)(PPh3)3. Here we report a series of S-bridged
W-Ru dinuclear complexes obtained therefrom, and a thorough
investigation of their reactivity toward H2 and protons. To assess
the mechanism of H2 activation by the W-Ru complexes, H/D
exchange reactions were also carried out with the hydrogenated
products, and their deprotonation and H2 dissociation reactions
were examined.
were convenient entries into the construction of various het-
1
1
erometallic sulfido clusters with Fe, Cu, Pd, Ag, and Au.
(
6) (a) Laurie, J. C. V.; Duncan, L. D.; Haltiwanger, R. C.; Weberg, R. T.;
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C.; Mealli, C.; Meli, A.; Sabat, M. Inorg. Chem. 1986, 25, 4618. (c) Linck,
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2
002, 1494.
(
7) (a) Volbeda, A.; Charon, M.-H.; Piras, C.; Hatchikian, E. C.; Frey, M.;
Fontecilla-Camps, J. C. Nature, 1995, 373, 580. (b) Happe, R. P.;
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Results and Discussion
3
85, 126. (c) Frey, M. Struct. Bonding 1998, 90, 97. (d) Ogata, H.;
Mizoguchi, Y.; Mizuno, N.; Miki, K.; Adachi, S.-I.; Yasuoka, N.; Yagi,
Synthesis of S-Bridged W-Ru Complexes. A series of
W-Ru dinuclear complexes were synthesized in high yield from
the reactions of half-sandwich dithio- and trithio-complexes of
W(VI) with phosphine/chloride complexes of Ru(II). The
reactions of the tungsten trithio complex (PPh4)[Cp*W(S)3] (1)
T.; Yamauchi, O.; Hirota, S.; Higuchi, Y. J. Am. Chem. Soc. 2002, 124,
1
1 628.
(
8) (a) Lawrence, J. D.; Li, H.; Rauchfuss, T. B.; B e´ nard, M.; Rohmer, M.-M.
Angew. Chem., Int. Ed. Engl. 1999, 38, 3178. (b) Gloaguen, F.; Lawrence,
J. D.; Rauchfuss, T. B. J. Am. Chem. Soc. 2001, 123, 9476. (c) Zhao, X.;
Georgakaki, I. P.; Miller, M. L.; Yarbrough, J. C.; Darensbourg, M. Y. J.
Am. Chem. Soc. 2001, 123, 9710. (d) Zhao, X.; Georgakaki, I. P.; Miller,
M. L.; Mejia-Rodriguez, R.; Chiang, C.-Y.; Darensbourg, M. Y. Inorg.
Chem. 2002, 41, 3917. (e) Pavlov, M.; Siegbahn, P. E. M.; Blomberg, M.
R. A.; Crabtree, R. H. J. Am. Chem. Soc. 1998, 120, 548. (f) Niu, S.;
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1
2
with 1 equiv of RuCl2(PPh3)3 and RuCl(H)(PPh3)3 in CH3CN
at room temperature yielded the W-Ru complexes with three
bridging sulfides, Cp*W(µ-S)3RuX(PPh3)2 (4a; X ) Cl, 4b; X
(
)
H), in 77% and 83% yields, respectively. The crystals
979. (b) Lai, C.-H.; Reibenspies, J. H.; Darensbourg, M. Y. Angew. Chem.,
obtained from a CH2Cl2/hexane solution of 4a and those from
a toluene/hexane solution of 4b were subjected to X-ray structure
analysis. These compounds are moderately sensitive toward
oxygen and moisture, and the combustion analysis and the H
and P{ H} NMR spectra are in accord with the formulation.
The two phosphine ligands at Ru are equivalent in the P{ H}
NMR spectra for both 4a and 4b. In the case of 4b, a triplet
signal at δ ) -10.30 in the H NMR spectrum and the IR ν-
(Ru-H) band at 1930 cm suggest the existence of a Ru-H
bond. Thus during the reactions of (PPh4)[Cp*W(S)3] (1) with
RuCl(X)(PPh3)3 (X ) Cl, H), one phosphine ligand is liberated
along with the formation of PPh4Cl, while one chloride ligand
or one hydride ligand remains intact at the Ru center.
Int. Ed. Engl. 1996, 35, 2390. (c) Steinfeld, G.; Kersting, B. J. Chem. Soc.,
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1
1
999, 1935. (f) Sellmann, D.; Geipel, F.; Lauderbach, F.; Heinemann, F.
3
1
1
W. Angew. Chem., Int. Ed. Engl. 2002, 41, 632. (g) Musie, G.; Farmer, P.
J.; Tuntulani, T.; Reibenspies, J. H.; Darensbourg, M. Y. Inorg. Chem.
31
1
1
996, 35, 2176. (h) Liaw, W.-F.; Chiang, C.-Y.; Lee, G. H.; Peng, S.-M.;
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M.; Contakes, S. M.; Rauchfuss, T. B. J. Am. Chem. Soc. 1999, 121, 9736.
1
(
j) Lyon, E. J.; Georgakaki, I. P.; Reibenspies, J. H.; Darensbourg, M. Y.
-
1
Angew. Chem., Int. Ed. Engl. 1999, 38, 3178. (k) Lawrence, J. D.; Li, H.;
Rauchfuss, T. B.; B e´ nard, M.; Rohmer, M.-M. Angew. Chem., Int. Ed. Engl.
2
001, 40, 1768. (l) Razavet, M.; Davies, S. C.; Hughes, D. L.; Pickett, C.
J. J. Chem. Soc., Chem. Commun. 2001, 847.
(
10) (a) Kawaguchi, H.; Yamada, K.; Lang, J.-P.; Tatsumi, K. J. Am. Chem.
Soc. 1997, 119, 10 346. (b) Kawaguchi, H.; Tatsumi, K. Angew. Chem.,
Int. Ed. 2000, 40, 1266.
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Kawaguchi, H.; Ohnishi, S.; Tatsumi, K. Inorg. Chim. Acta, 1998, 283,
The reaction of (PPh4)[Cp*W(O)(S)2] (2) with RuClX(PPh3)3
1
36. (c) Lang, J.-P.; Kawaguchi, H.; Tatsumi, K. J. Organomet. Chem.
998, 569, 109. (d) Lang, J.-P.; Tatsumi, K. Inorg. Chem. 1999, 38, 1364.
(X ) Cl, H) followed by a standard workup afforded the
1
(
e) Lang, J.-P.; Tatsumi, K. J. Organomet. Chem. 1999, 579, 332. (f) Lang,
J.-P.; Kawaguchi, H.; Tatsumi, K. J. Chem. Soc., Chem. Commun. 1999,
315.
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2
J. AM. CHEM. SOC.
9
VOL. 125, NO. 26, 2003 7979

A R T I C L E S
Ohki et al.
Table 1. Selected Bond Distances (Å) and Angles (deg) for Cp*W(µ-S)3RuX(PPh3)2 (X ) Cl (4a), H (4b)) and Cp*W(O)(µ-S)2RuX(PPh3)2 (X
Cl (5a), H (5b))
)
4a
4b
5a
5b
W-Ru
2.6188(2)
2.2302(7)
2.2159(7)
2.2314(7)
2.4079(7)
2.4981(8)
2.5056(7)
2.4192(7)
68.63(2)
W-Ru
2.6106(3)
2.2226(8)
2.2253(7)
2.2367(9)
2.5387(8)
2.4719(8)
2.4931(8)
1.56(3)
W-Ru
2.8511(4)
1.746(4)
2.261(1)
2.250(1)
2.320(1)
2.230(1)
2.428(1)
76.96(4)
76.98(4)
W-Ru
2.8492(4)
1.730(4)
2.264(1)
2.276(1)
2.329(1)
2.331(1)
1.62(5)
W-S1
W-S1
W-O
W-O
W-S2
W-S2
W-S1
W-S2
Ru-S1
Ru-S2
Ru-Cl
W-S1-Ru
W-S2-Ru
W-S1
W-S2
Ru-S1
Ru-S2
Ru-H
W-S1-Ru
W-S2-Ru
W-S3
W-S3
Ru-S1
Ru-S1
Ru-S2
Ru-S2
Ru-S3
Ru-S3
Ru-Cl
Ru-H
76.67(4)
76.39(3)
W-S1-Ru
W-S2-Ru
W-S3-Ru
W-S1-Ru
W-S2-Ru
W-S3-Ru
66.11(2)
67.29(2)
66.75(2)
67.19(2)
66.83(2)
analytically pure W-Ru bis(µ-sulfido) complexes Cp*W(O)-
µ-S)2RuX(PPh3)2 (5a; X ) Cl, 5b; X ) H) in 82% and 86%
(
yields, respectively. In these dinuclear complexes, the oxo ligand
does not bridge the two metal centers, as suggested by the
-
1
-1
characteristic ν(WdO) bands at 895 cm (5a) and 901 cm
5b) in the IR spectra.13 The X-ray quality crystals were grown
(
by layering hexane onto a CH2Cl2 solution of 5a or onto a
toluene solution of 5b. Again, one phosphine ligand was
removed from Ru during the reactions, and coordination of a
chloride or a hydride ligand at Ru was retained. In a similar
manner, the W-Ru complexes having a WdNPh moiety,
Cp*W(NPh)(µ-S)2RuX(PPh3)2 (6a; X ) Cl, 6b; X ) H) were
12
synthesized using (PPh4)[Cp*W(NPh)(S)2] (3), which were
1
31
1
characterized by H and P{ H} NMR spectra, IR, and by FAB-
mass for 6a. Their NMR spectra resemble those of the
corresponding W-Ru complexes having a terminal oxo group,
5
a and 5b. The IR spectra are featured by the bands at 1336
-
1
-1
cm (6a) and 1346 cm (6b) which are assignable to the
WdNPh stretching vibrations.14
There appear two doublets in the 31P{ H} NMR spectra of
the chloride complexes, 5a and 6a, at room temperature,
indicating that the two phosphine ligands are chemically
nonequivalent. This observation is consistent with the solid-
state structure of 5a as will be shown below. On the other hand,
the P{ H} NMR spectra of the hydride congeners, 5b and 6b,
show a single peak at room temperature. However, the
phosphorus signal for 5b was found to be significantly
broadened with lowering the temperature, and to split into two
broad peaks at -85 °C. Thus the site exchange of the two
phosphine ligands occurs more readily for the hydride com-
plexes.
1
31
1
Figure 1. Molecular structures of Cp*W(µ-S)3RuH(PPh3)2 (4b) (top) and
Cp*W(O)(µ-S)2RuH(PPh3)2 (5b) (bottom).
latter two hydride complexes are shown in Figure 1. The
hydrides were located at reasonable positions in the last Fourier
maps, and they are included in the drawings. For 4a and 4b,
three sulfur atoms bridge the Cp*W unit and Ru, and the slightly
distorted octahedral geometry at Ru is completed by coordina-
tion of two phosphine ligands and a chloride (or a hydride). In
the case of 5a and 5b, the two metal centers are linked by two
sulfur atoms, and the Ru site assumes a square pyramidal
geometry with one phosphine at the apical site. Consequently,
the two phosphines are nonequivalent in the solid state, while
Structures of the W-Ru Dinuclear Complexes. The X-ray
structure analyses were carried out for Cp*W(µ-S)3RuX(PPh3)2
(4a; X ) Cl, 4b; X ) H) and Cp*W(O)(µ-S)2RuX(PPh3)2 (5a;
X ) Cl, 5b; X ) H), and selected geometrical parameters are
summarized in Table 1. Since their molecular structures are very
similar to those of 4b and 5b, the perspective views of only the
(
13) (a) Faller, J. W.; Ma, Y. Organometallics 1988, 7, 559. (b) Legzdins, P.;
Phillips, E. C.; Rettig, S. J.; S a´ nchez, L.; Trotter, J.; Yee, V. C.
Organometallics 1988, 7, 1877. (c) Faller, J. W.; Ma, Y. Organometallics
3
1
1
those of 5b are fluxional in solution on the P{ H} NMR time
scale. The WS2Ru rhomboids are slightly puckered, where the
dihedral angles between the WS2 and RuS2 planes are 18.5°
1
989, 8, 609. (d) Gorzellik, M.; Bock, H.; Gang, L.; Nuber, B.; Ziegler,
M. L. J. Organomet. Chem. 1991, 412, 95. (e) Rau, M. S.; Kretz, C. M.;
Geoffroy, G. L.; Rheingold, A. L. Organometallics 1993, 12, 3447. (f)
Rau, M. S.; Kretz, C. M.; Geoffroy, G. L.; Rheingold, A. L.; Haggerty, B.
S. Organometallics 1994, 13, 1624. (g) Chakraborty, D.; Bhattacharjee,
M.; Kr a¨ tzner, Siefken, R.; Roesky, H. W.; Uson, I.; Schmidt, H.-G.
Organometallics, 1999, 18, 106.
(5a) and 10.5° (5b). The apical phosphine coordination for the
hydride complex 5b tilts notably toward the less bulky hydride
position. Thus the W-Ru-P1 angle of 120.0° for 5b is large,
compared with the corresponding angle of 100.7° for the
(
14) (a) Glassman, T. E.; Vale, M. G.; Schrock, R. R. Organometallics 1991,
1
0, 4046. (b) Legzdins, P.; Phillips, E. C.; Rettig, S. J.; Trotter, J.; Veltheer,
J. E.; Yee, V. C. Organometallics 1992, 11, 3104.
7
980 J. AM. CHEM. SOC. VOL. 125, NO. 26, 2003
9

Heterolytic Cleavage of Dihydrogen
A R T I C L E S
F
Table 2. Selected Bond Distances (Å) and Angles (deg) for [Cp*W(OH)(µ-S)2RuH(PPh3)2](BAr 4) (7a‚2C4H10O) and
Cp*W(OH)(µ-S)2RuH(PPh3)2](OTf) (7b)
[
7a
7b
W-Ru
W-O1
W-S1
W-S2
Ru-S1
Ru-S2
2.8124(5)
1.829(4)
2.248(1)
2.232(1)
2.335(1)
2.291(1)
Ru-H
1.56(6)
2.580(7)
75.68(4)
76.84(4)
W-Ru
W-O1
W-S1
W-S2
Ru-S1
Ru-S2
2.8306(4)
1.858(4)
2.249(1)
2.233(1)
2.322(1)
2.299(1)
Ru-H
1.68(8)
2.66(1)
76.49(3)
77.30(4)
O1-O2
O1-O2
W-S1-Ru
W-S2-Ru
W-S1-Ru
W-S2-Ru
Scheme 2
chloride congener 5a. The WdO bond lengths of 1.746(4) and
Figure 2. Structure of the complex cation of [Cp*W(OH)(µ-S)2RuH(PPh3)2]-
(BArF )‚2C H O (7a‚2C H O). The hydrogen atom bound to Ru was
crystallographically located, whereas the hydroxyl hydrogen is added at an
appropriate position in the figure in order to emphasize the hydrogen bonding
with the ether molecule.
14
1
.730(4) Å are as expected for multiple bonding.
The W-S distances of 2.2159(7) - 2.2367(9) for 4a and 4b
are similar to those of Cp*W(S)(µ-S)2FeCl2 (W-µS; av. 2.25
4
4
10
4
10
1
5
Å), and fall between the W-S (thiolate) single bond lengths
of half-sandwich thiolate complexes of W(VI) (2.33-2.45
solution from dark green to purple. The reaction was complete
1
0,16
Å)
(
and the WdS multiple bond lengths of (PPh4)[Cp*W-
within five minutes at room temperature, and [Cp*W(OH)(µ-
S)3] (1) (av. 2.19 Å).10a Thus, there appears to be partial W-S
F
S)2RuH(PPh3)2][BAr 4] (7a) was isolated as a purple powder
multiple bond character in the W-Ru dinuclear structures, and
their oxidation states were assigned to be W(VI) and Ru(II).
For 4b, the Ru-S1 bond which is trans to the hydride ligand is
in 84% yield. Thus in this reaction, H2 splits into the hydridic
center attached to Ru and the protic center at the oxo ligand,
where the formal oxidation states of the metal atoms are
unchanged. The imido analogue of 5a, Cp*W(NPh)(µ-S)2RuCl-
0
.046-0.067 Å longer than the other two Ru-S bonds, which
17
accounts for the strong trans influence of hydride. On the other
hand, the Ru-S bonds of 5a and 5b are substantially short,
while the W-S bonds are elongated, compared with those of
the triply bridging structures of 4a and 4b. This may have
something to do with the different coordination numbers of Ru,
and the coordinatively unsaturated Ru centers of 5a and 5b could
be stabilized by π-interactions with the bridging sulfides. The
observed W-Ru distances indicate dative bonding between the
electron rich Ru(II) center and the electron deficient W(VI)
center, where the triply bridged W-Ru bonds of 4a and 4b are
much shorter and the W-S-Ru angles are more acute.
Activation of H2 by the W-Ru Complexes. Considering
the coordinative unsaturation of Ru in Cp*W(O)(µ-S)2RuX-
(
PPh3)2 (6a), was also found to activate atmospheric H2 under
F
the presence of NaBAr 4, resulting in the formation of
F
[Cp*W(NHPh)(µ-S)2RuH(PPh3)2][BAr 4] (8).
Complexes 7a and 8 were characterized spectroscopically,
and the structure of 7a was determined by crystallographic
analysis. Their H NMR spectra show resonances for W-OH
and Ru-H at δ 9.07 and -3.37 for 7a, and at δ 5.69 and δ
1
-
3.98 for 8. Disappearance of the characteristic ν(WdO)
-
1
band and appearance of a ν(Ru-H) band at 2019 cm and a
-1
ν(O-H) band at 3453 cm in the IR spectrum of 7a also agree
with the formation of the W-OH and Ru-H moieties. As in
the case of 5b, two phosphines in 7a and 8 are equivalent in
the P{ H} NMR spectra at room temperature, due to a facile
site exchange at Ru.
31
1
(PPh3)2 (5a; X ) Cl, 5b; X ) H), their reactions with H2 were
examined. There was no sign of reaction upon heating a CH2-
F
Single crystals of [Cp*W(OH)(µ-S)2RuH(PPh3)2][BAr 4] (7a)
Cl2 solution of 5a or 5b under 10 atm of H2. However, when
suitable for X-ray diffraction study were obtained from an ether
solution at -78 °C. The complex was crystallized with ether
molecules as solvent of crystallization, and there was no short
F
F
18
5
a was treated in CH2Cl2 with NaBAr 4 (Ar ) 3,5-(CF3)2C6H3)
under 1 atm of H2, we noticed a quick color change of the
F
contact between the complex cation and the BAr 4 anion. Each
(
15) Kawaguchi, H.; Tatsumi, K., unpublished result.
(
16) (a) O’Regan, M. B.; Liu, A. H.; Finch, W. C.; Schrock, R. R.; Davis, W.
M. J. Am. Chem. Soc. 1990, 112, 4331. (b) Brunet, N.; Legzdins, P.; Trotter,
J.; Yee, V. C. Acta Crystallogr. Sect. C, 1995, 51, 193. (c) Cao, R.; Tatsumi,
K. Inorg. Chem. 2002, 41, 4102.
ether molecule is situated in the neighborhood of the hydroxyl
group of the complex cation, with O-O separation of 2.58 Å,
indicating the WOH-O(ether) hydrogen bonding. The cation
of 7a with the hydrogen-bonded ether is shown in Figure 2,
and the selected geometrical parameters are listed in Table 2.
(17) Crabtree, R. H. In The Organometallic Chemistry of The Transition Metals,
2
nd ed.; Wiley & Sons: New York, 1994.
(18) Brookhart, M.; Grant, B.; Volpe, J. Organometallics 1992, 11, 3920.
J. AM. CHEM. SOC.
9
VOL. 125, NO. 26, 2003 7981

A R T I C L E S
Ohki et al.
Scheme 3
The dinuclear core geometry is very similar to those of Cp*W-
(
O)(µ-S)2RuH(PPh3)2 (5b), except for the W-O distance. The
Figure 3. Structure of [Cp*W(OH)(µ-S)2RuH(PPh3)2](OTf) (7b). The
hydrogen bound to Ru was located by the X-ray analysis, and the hydroxyl
hydrogen was put at a calculated position.
W-O bond length of 1.829(4) Å is substantially longer than
the WdO distance of 1.746(4) Å in 5a, which confirms that
the oxygen atom attached to W is no longer a terminal oxo
ligand but a hydroxyl group. It may be worth noting that the
W-S bond lengths of 7a are slightly shorter by 0.030 Å (av.)
than those of 5a. The shortening of the W-S bonds reflects
the lesser extent of π donaton to W from the hydroxy ligand
than that from oxo ligand, thereby allowing stronger π donation
from the bridging sulfides.
(7b) were isolated in 97% and 87% yields, respectively. In these
reactions, the hydridic site at Ru remained intact, and no H2
evolution was observed. Conversion of 7b into 7a was suc-
F
cessful on anion exchange with NaBAr 4 in CH2Cl2. The
occurrence of protonation at the oxo ligand points to two
significant aspects: a) WdO is a more basic site than Ru-H,
and b) the OH hydrogen in 7a or 7b is acidic in character.
Intriguingly, neither Cp*W(O)(µ-S)2RuCl(PPh3)2 (5a) nor
F
Cp*W(NPh)(µ-S)2RuCl(PPh3)2 (6a) reacts with NaBAr 4 alone
Scheme 4
under N2. As was mentioned earlier, 5a (and 6a) does not react
F
with H2 in the absence of NaBAr 4, even under 10 atm H2. Thus
F
both NaBAr 4 and H2 must be present for the reaction to
proceed, although the H2 activation by 5a and 6a would
presumably occur after the removal of chloride from the Ru
F
site. The salt NaBAr 4 does not react with H2 under this
condition. In contrast, the tris(µ-sulfido) complex Cp*W(µ-
F
S)3RuCl(PPh3)2 (4a) reacts readily with NaBAr 4 in the absence
of H2 to give a dark brown solid. Although we were unable to
characterize the dark brown product, it is interesting to note
F
that the reaction of 4a with NaBAr 4 under atmospheric H2
1
produces a solid, the H NMR spectrum of which is very similar
Complex 7b, isolated as dark purple crystals, was character-
ized by spectroscopic data and by combustion analysis, and its
structure was determined by X-ray analysis. The event of
selective protonation at WdO was indicated by the disappear-
ance of the characteristic ν(WdO) band, and by the persistence
to that of the above dark brown product. The difference between
a and 5a is the coordination number of Ru, and the chloride
at the octahedral Ru seems to be more labile. Taking these
observations into account, we propose that the reaction of 5a
4
F
-1
with NaBAr 4/H2 is initiated by coordination of H2 to the
of the Ru-H band at 2015 cm in the IR spectrum. Observation
1
pentacoordinate Ru as shown in Scheme 3. The resulting
octahedral H2 complex, designated as (A) in Scheme 3, would
have facilitated dissociation of chloride in the reaction with
NaBAr 4. Removal of chloride from A leads to the square-
pyramidal intermediate with η -H2 (B), and subsequently the
of H NMR resonances at δ 10.8 (W-OH) and δ -5.96 (Ru-
H) is consistent with the interpretation of the IR spectrum.
3
1
1
Similar to 7a, there appears a single peak in the P{ H} NMR
spectrum at room temperature, and the two phosphine ligands
are thus fluxional. The molecular structure of 7b is presented
in Figure 3, and selected bond lengths and angles are compared
with those of 7a in Table 2. The most notable feature of the
crystal structure is the short contact between the W-OH group
F
2
H2 molecule splits into the Ru-H and W-OH forms in 7a.
2
Formation of η -H2 complexes prior to the heterolytic H2
cleavage has occasionally been speculated.3b,4, 5c The mechanism
of the H2-splitting process from B to 7a will be discussed below.
Protonation Reactions of the Hydride Complexes. The
hydridic centers of transition metal complexes often react with
-
and the anion OTf . The O-O separation of 2.66(1) Å is
indicative of hydrogen bonding. The W-O bond length of
1.858(4) Å is obviously elongated by protonation, as compared
with the WdO bond of 5b, and it is slightly longer than the
W-OH distance of 7a, too. The O-O separation is also longer
for 7b by 0.08 Å. The hydroxyl group of 7a is hydrogen bonded
to the ether oxygen, and the longer W-OH and O-O distances
+
protons (H ), and evolve H2. Contrary to this preconception,
we found the oxo ligand of Cp*W(O)(µ-S)2RuH(PPh3)2 (5b)
to be protonated when it was treated in THF with an equimolar
amount of [H(OEt2)2][BAr 4] or HOTf. [Cp*W(OH)(µ-S)2RuH-
F
F
-
(
PPh3)2][BAr 4] (7a) and [Cp*W(OH)(µ-S)2RuH(PPh3)2](OTf)
for 7b suggest that the hydrogen bond with OTf is weaker
7982 J. AM. CHEM. SOC.
9
VOL. 125, NO. 26, 2003

Heterolytic Cleavage of Dihydrogen
A R T I C L E S
Table 3. Selected Bond Distances (Å) and Angles (deg) for [Cp*W(µ-S)3RuL(PPh3)2](OTf) (L ) CH3CN (9), Co (10))
9
10
W-Ru
W-S1
W-S2
W-S3
Ru-S1
Ru-S2
Ru-S3
Ru-N
2.6264(3)
2.2269(8)
2.2306(9)
2.2215(8)
2.4084(8)
2.5148(8)
2.5069(8)
2.046(3)
W-S1-Ru
W-S2-Ru
W-S3-Ru
68.90(2)
66.90(2)
67.17(2)
W-Ru
W-S1
W-S2
W-S3
Ru-S1
Ru-S2
Ru-S3
Ru-C
2.660(1)
2.226(3)
2.207(4)
2.226(4)
2.493(4)
2.498(4)
2.491(4)
1.86(2)
W-S1-Ru
W-S2-Ru
W-S3-Ru
68.5(1)
68.38(10)
66.40(10)
than the interaction with ether. The coordination geometries at
W and Ru resemble those of 5b and 7a.
In contrast to the selective protonation at the oxo ligand of
investigated. The protic character of the WOH hydrogen was
established by the observation that “deprotonation” of the
+
complex cation [Cp*W(OH)(µ-S) RuH(PPh ) ] (7a,b) was
2
3 2
5b, the analogous reaction of HOTf with Cp*W(µ-S)3RuH-
induced selectively by a small excess of NEt , resulting in
3
(PPh3)2 (4b) occurred at the hydride site. Addition of HOTf to
quantitative formation of Cp*W(O)(µ-S)2RuH(PPh3)2 (5b).
a THF solution of 4b at room temperature caused an immediate
evolution of H2 to afford a dark red solution. Although the dark
red product has not been characterized, it is presumed to be a
cationic THF complex [Cp*W(µ-S)3Ru(THF)(PPh3)2][OTf],
because a CH3CN-adduct [Cp*W(µ-S)3Ru(CH3CN)(PPh3)2]-
Evolution of H2, which would produce [Cp*W(O)(µ-S)2Ru-
+
(NEt3)(PPh3)2] , did not take place in this reaction.
Scheme 6
[OTf] (9) and a CO-adduct [Cp*W(µ-S)3Ru(CO)(PPh3)2][OTf]
(10) were isolated upon treating the dark red solution with CH3-
CN and CO, respectively. The IR spectrum of 9 exhibits bands
-
1
-
for CH3CN at 2210 cm , and for OTf at 1270, 1220, 1150,
-
1
and 636 cm , while complex 10 was characterized by a strong
-
1
1
Scheme 7
CO band at 1990 cm . Their H NMR spectra agree with the
formulation, and the signal for free CH3CN appeared for 9, when
the measurement was performed in CD3CN. The structures of
9
and 10 were confirmed by crystallographic analysis, and the
selected bond lengths and angles are given in Table 3. Similar
to the molecular structures of Cp*W(µ-S)3RuX(PPh3)2 (4a; X
)
Cl, 4b; X ) H), the two metal centers are bridged by three
sulfides, and CH3CN or CO is coordinated at Ru. A notable
difference in the structures of 4a, 4b, 9, and 10 is the Ru-S1
bond lengths trans to chloride (2.4079(7) Å), hydride (2.5387-
(8) Å), CH3CN (2.4084(8) Å), and CO (2.493(4) Å), which show
the strong trans influence of hydride and CO.
Scheme 5
We mentioned earlier in this paper that the hydride of Cp*W-
µ-S)3RuH(PPh3)2 (4b) reacted readily with HOTf. Transition
(
metal hydrides are potential bases, and could interact with the
acidic W-OH group. As a matter of fact, treatment of Cp*W-
(µ-S)3RuH(PPh3)2 (4b) with 7a in THF resulted in immediate
evolution of H2, and the subsequent addition of CH3CN into
the resulting dark-brown solution produced 5b and [Cp*W(µ-
F
S)3Ru(CH3CN)(PPh3)2][BAr 4] (9). Obviously H2 was formed
by an intermolecular coupling of the hydroxyl hydrogen in 7a
and the hydride in 4b. This facile H2 formation raises the
intriguing question as to why 7a or 7b does not evolve H2 by
itself via an intermolecular or intramolecular H-H coupling
pathway. They are stable in THF under an inert atmosphere.
Hydridic character of the Ru-H bond may be weak, and/or the
-
hydrogen bonding with OTf or ether may decrease the acidity
of the hydroxyl hydrogen.
Although the complex cation [Cp*W(OH)(µ-S)2RuH(PPh3)2]+
is stable in THF, it was found to be labile in the presence of
CH3CN or under CO atmosphere. Upon addition of CH3CN to
a THF solution of 7a or 7b, the complex was gradually
converted into [Cp*W(O)(µ-S)2Ru(CH3CN)(PPh3)2](X) (11a;
Deprotonation and H2 Evolution. Addition of hydrogen at
the oxo ligand can be accomplished either by the heterolytic
cleavage of H2 or by protonation. In expectation of obtaining
insights into the mechanism of heterolytic H2 activation, the
reverse processes of H-H cleavage and protonation were
J. AM. CHEM. SOC.
9
VOL. 125, NO. 26, 2003 7983

A R T I C L E S
Ohki et al.
Table 4. Selected Bond Distances (Å) and Angles (deg) for
Scheme 9
[
Cp*W(O)(µ-S)2Ru(CH3CN)(PPh3)2](OTf) (11b)
11b
W-Ru
2.8603(3)
1.727(3)
2.2644(9)
2.2650(9)
2.3648(9)
2.3354(8)
2.063(3)
76.65(3)
76.87(3)
W-O
W-S1
W-S2
Ru-S1
Ru-S2
Ru-N
W-S1-Ru
W-S2-Ru
F
NaBAr 4 under a D2 atmosphere, and it was characterized by
F
X ) BAr 4, 11b; X ) OTf) with evolution of H2. The product
was isolated as a grayish blue crystalline powder in 95% yield.
Formation of H2 was detected by a separate NMR tube
experiment in THF-d8 with a small amount of CH3CN, where
the free H2 signal appeared at δ 4.55. Complexes 11a and 11b
were characterized by the IR bands associated with the WdO
1
2
31
means of H, H, and P NNR spectra. In either of the reactions
with D2 and CH3OD in NMR tubes, the intensity of the W-OH
signal (or the W-OD signal) remains nearly equal to that of
the Ru-H signal (or Ru-D signal). In other words, during the
H/D exchange, the W-OH and Ru-H proton signals decrease
approximately at the same rate, and the situation is similar to
1
31
1
bond and CH3CN, and by H and P{ H} NMR spectra. As in
the case of 5a, the two phosphine ligands are chemically
nonequivalent in the 31P NMR spectrum. Crystals suitable for
X-ray analysis were grown by layering ether onto a THF
solution of 11b. The X-ray derived geometric parameters are
listed in Table 4. There is no short contact between the complex
cations and the anions in the crystals. The dinuclear structure
of the complex cation is analogous to those of 5a and 5b, in
which the Ru atom adopts a distorted square pyramidal
coordination geometry with an apical PPh3, and with one PPh3,
two µ-S atoms, and one CH3CN molecule at the basal positions.
2
the concomitant increases of the corresponding H signals.
Scheme 10
Scheme 8
H/D Exchange Experiments. In the previous section, we
mentioned that the hydride complex Cp*W(O)(µ-S)2RuH(PPh3)2
(5b) appeared not to react under 10 atm H2. To ascertain if 5b
is really inert to external H2, an H/D exchange reaction was
conducted in an NMR tube at room temperature, and the reaction
was monitored by H NMR. Introduction of D2 onto a C6D6
Scheme 11
1
solution of 5b gave rise to Cp*W(O)(µ-S)2RuD(PPh3)2 (5b-d).
1
Formation of HD and H2 was noted in the H NMR. The
reaction is relatively slow and is nearly completed in 1 day.
The exchange between D2 and the hydride is most likely to
2
proceed through coordination of η -D2. The tri(µ-sulfido)
hydride complex Cp*W(µ-S)3RuH(PPh3)2 (4b) was also found
to undergo the H/D exchange between the hydride and 1 atm
D2 to produce Cp*W(µ-S)3RuD(PPh3)2 (4b-d).
The NMR tube experiments were also carried out for the H/D
F
exchange reactions of [Cp*W(OH)(µ-S)2RuH(PPh3)2][BAr 4]
As one might expect, CH3OD does not react with the hydride
of Cp*W(O)(µ-S)2RuH(PPh3)2 (5b). It may also be expected
that a fast exchange between W-OH and D2 is unlikely to
proceed. Therefore, we propose that the H/D exchange at the
W-OH site of 7a under D2 is actually initiated by deuteration
of the hydride at Ru via D2 coordination, and the H/D scramble
between the W-OH and Ru-D sites follows. Likewise, in the
reaction between 7a and CH3OD, deuteration probably occurs
first at W-OH, which would then scramble over the two sites.
(7a). Surprisingly, exposure of a THF-d8 solution of 7a to D2
lead to a facile exchange of both hydridic center attached to
Ru and protic center on the OH group, giving rise to [Cp*W-
F
(
OD)(µ-S)2RuD(PPh3)2][BAr 4] (7a-d2) within 1 day, and the
1
formation of HD and H2 was identified in the H NMR
spectrum. More surprisingly, the treatment of 7a with CH3OD
also resulted in 7a-d2. The deuterated complex 7a-d2 was
synthesized in a preparative scale by the reaction of 5a with
7984 J. AM. CHEM. SOC.
9
VOL. 125, NO. 26, 2003

Heterolytic Cleavage of Dihydrogen
A R T I C L E S
Scheme 12
Scheme 13
Since the H/D exchanges occur simultaneously at W-OH and
Ru-H in the H NMR time scale, the H(D) scramble between
these sites must be much faster than the deuteration processes
at Ru-H with D2 and at W-OH with CH3OD.
results in heterolytic H-H bond splitting. A proton is transferred
to a counteranion, an external base, or to a basic site within the
1
2
molecule. In the η -H intermediate (B), the oxo group, the
2
F
-
bridging sulfides, and the counteranion [BAr ] may act as
proton acceptors. However, proton abstraction by [BAr ] is
4
F
-
We have carried out a crossover experiment for the H2(D2)
4
F
formation from [Cp*W(OH)(µ-S)2RuH(PPh3)2][BAr 4] (7a) and
unlikely to occur, because a proton is only lost when a conjugate
F
F
[
Cp*W(OD)(µ-S)2RuD(PPh3)2][BAr 4] (7a-d2) in the presence
base such as Et O or H O is present to give [H(OEt ) ](BAr )
2
2
2 2
4
of CH3CN (see Scheme 11). In an NMR tube, a 1:1 mixture of
a and 7a-d2 was dissolved in THF-d8 and one drop of CH3-
F
or [H3O](BAr 4), while the reaction of 5a with H2 was carried
out in CH2Cl2. A direct intramolecular proton abstraction by
WdO is also ruled out, because the WdO group is far away
from the Ru coordination sphere.
7
1
CN was added, followed by immediate H NMR measurement.
The spectrum clearly shows the signals of H2 and HD in the
1
:2 intensity ratio, and also points to the quantitative formation
Thus a plausible pathway for the H2 activation is the one
F
of [Cp*W(O)(µ-S)2Ru(CH3CN)(PPh3)2][BAr 4] (11a). If the H2
evolution occurs within each molecule of 7a and 7a-d2, H2 and
D2 would be produced. On the other hand, if the reaction
proceeds via an intermolecular pathway, a statistical amount of
HD would also be generated, which is in accord with the
experimental result. However, the formation of HD may also
be explained in terms of a facile intermolecular/intramolecular
H/D scrambling between 7a and 7a-d2 before the H2 evolution.
This possibility could not be ruled out.
involving an intermolecular H-H splitting as shown in Scheme
1
2. This mechanism is analogous to the known deprotonation
2
reactions of metal-bound η -H2 molecules promoted by external
bases. Another way to view this mechanism is that the reaction
proceeds via the intermediate having an intermolecular interac-
tion between the hydridic Ru-H site and the protic W-OH
site. This Ru-H-H-O-W interaction is relevant to the so-
called nonclassical hydrogen-bonding found in some transition
metal hydride complexes, e.g., the Ir-H-H-N interaction
in [Ir{H(η -SC5H4NH)}2(PCy3)2]BF4 and the Ir-H-H-O
interaction observed in [Ir(H)2{(C9H6N)NC(OH)Me}(PPh3)2]-
1
9
Mechanistic Aspects of the Reversible H2 Activation. We
emphasized in Scheme 3 that the H2 activation reaction of
1
4a
F
Cp*W(O)(µ-S)2RuCl(PPh3)2 (5a) with NaBAr 4 could be initi-
4
b
2
(SbF6).
ated by formation of an η -H2 complex Cp*W(O)(µ-S)2RuCl-
On the other hand, a possibility of proton migration over the
(
H2)(PPh3)2 (A), and that dissociation of chloride from the
2
intermediate, leading to another η -H2 intermediate [Cp*W(O)-
µ-S sites, by way of the µ-SH intermediate [Cp*W(O)(µ-S)(µ-
F
F
(µ-S)2Ru(H2)(PPh3)2](BAr 4) (B), would then be facilitated by
SH)RuH(PPh3)2](BAr 4) (C), is not ruled out (Scheme 13). The
F
NaBAr 4. In this section, the mechanism of the subsequent H2
bridging sulfide in (B) is in close vicinity to the molecular
splitting process of B to give [Cp*W(OH)(µ-S)2RuH(PPh3)2]-
hydrogen at Ru, a lone pair of which is capable of abstracting
a proton from the η -H2 molecule. The resulting mercapto group
F
2
(
BAr 4) (7a) is discussed (Scheme 12). This process can be
reversible, which would account for the mechanisms of H/D
is acidic, and would deriver the proton readily to the more basic
oxo group. The heterolytic cleavage of H2 by dinuclear µ-sulfido
complexes have been reported to generate a µ-SH bond and a
exchange reactions of 7a (and 7b) and facile H2 evolution in
F
CH3CN to generate [Cp*W(O)(µ-S)2Ru(CH3CN)(PPh3)2](BAr 4)
6
b,c,d
(11a). An alternative mechanism of the H2 evolution is also
M-H bond.
implicated at the bottom of Scheme 12, where addition of CH3-
CN to Ru of 7a precedes the H-H coupling.
It has been known that the enhanced acidity of molecular
hydrogen bound to electron deficient transition metal centers
(19) (a) Crabtree, R. H.; Siegbahn, P. E. M.; Eisenstein, O.; Rheingold, A. L.;
Koetzle, T. Acc. Chem. Res. 1996, 29, 348, and references therein. (b)
Stevens, R. C.; Bau, R.; Milstein, D.; Blum, O.; Koetzle, T. F. J. Chem.
Soc., Dalton Trans. 1990, 1429.
J. AM. CHEM. SOC.
9
VOL. 125, NO. 26, 2003 7985

A R T I C L E S
Ohki et al.
RuS W:
IR (Nujol): 1930 (w, nRu-H) cm-1. Anal. Calcd for C46
C, 53.02; H, 4.45; S, 9.23. Found: C, 52.82; H, 4.52, S, 9.18.
Synthesis of Cp*W(O)(µ-S) RuCl(PPh (5a). The procedure is
similar to the one used for the synthesis of 4a. The reaction of (PPh )-
Cp*W(S) (O)] (2) (0.94 g, 1.27 mmol) with RuCl (PPh (1.21 g,
.27 mmol) in CH CN (125 mL) gave Cp*W(O)(µ-S) RuCl(PPh (5a)
as a green powder (1.10 g, 82%). X-ray quality crystals were grown
H
46
P
Experimental Section
2
3
General Procedures. All reactions and the manipulations of air-
sensitive compounds were performed under nitrogen or argon atmo-
sphere using standard Schlenk techniques. Solvents were dried, degassed
2
3 2
)
4
[
1
2
2
3 3
)
and distilled from sodium/benzophenone ketyl (hexane, Et
DME, THF) or from CaH (CH CN, CH Cl ) under nitrogen. Deuterated
solvents were vacuum-transferred from sodium (benzene-d , toluene-
, THF-d ) or CaH (CD CN, CD Cl , CDCl ).
2
O, toluene,
3
2
3 2
)
2
3
2
2
6
1
from hexane/CH
2
Cl
2
at room temperature. H NMR (CDCl
3
): δ 7.28-
), 1.88 (s, 15 H, Cp*). P{ H} NMR (CDCl ): δ
). IR (Nujol):
W‚CH Cl : C,
d
8
8
2
3
2
2
3
31
1
7
6
8
4
.00 (m, 30 H, PPh
8.8 (d, JPP ) 30 Hz, PPh
95 (s, νWdO) cm . Anal. Calcd for C46
3
3
1H and 31P NMR spectra were acquired on a Varian INOVA-500
2
2
3
), 26.4(d, JPP ) 30 Hz, PPh
45ClOP RuS
3
1
spectrometer at 500 and 202 MHz, respectively. H NMR spectra were
referenced to the residual proton resonances of the deuterated solvents.
-1
H
2
2
2
2
9.29; H, 4.14; S, 5.60. Found: C, 48.81; H, 4.30; S, 5.46.
Synthesis of Cp*W(O)(µ-S) RuH(PPh (5b). The synthetic
procedure is analogous to that of 4b. The reaction of (PPh )[Cp*W-
S) (O)] (2) (0.97 g, 1.32 mmol) with RuClH (PPh (1.31 g, 1.28
mmol) in CH CN (125 mL) afford Cp*W(O)(µ-S) RuH(PPh (5b)
31
P chemical shifts were relative to the external reference of 85% H
3
-
2
3 2
)
PO . Infrared spectra were recorded on a Parkin Elmer 2000 FT-IR
4
4
spectrometer or a JASCO A3 spectrometer. ESI-MS spectra were
obtained from a Perkin-Elmer Sciex API 300 ion spray mass spec-
trometer or a Micromass LCT TOF-MS spectrometer. Elemental
analyses for C, H, N, and S were performed on a LECO CHNS-932
elemental analyzer where the crystalline samples were sealed in silver
capsules under argon. FAB-MS spectra were obtained on a JEOL JMS-
LCMATE mass spectrometer, where 3-nitrobenzyl alcohol was used
as the matrix. X-ray diffraction data were collected on a Rigaku
RASA-7 Quantum system and a Rigaku AFC7R equipped with an
ADSC Quantum1 CCD detector by using graphite-monochromated
MoKR radiation.
(
2
3 3
)
3
2
3 2
)
as a greenish brown crystalline powder (1.14 g, 86%). X-ray quality
crystals were grown from a hexane/toluene solution at room temper-
1
ature. H NMR (C
6
D
6
): δ 7.64-7.60 (m, 12 H, PPh
3
), 6.93-6.88 (m,
), 1.86 (s, 15 H, Cp*), -8.17 (t, JPH ) 33 Hz, 1 H, RuH).
P{ H} NMR (C ): δ 68.5 (s, PPh ). IR (Nujol): 2022 (w, νRu-H),
01 (s, νWdO) cm-1. Anal. Calcd for C46
RuS W: C, 53.83; H,
.52; S, 6.25. Found: C, 53.98; H, 4.65; S, 6.54.
Synthesis of Cp*W(NPh)(µ-S) RuCl(PPh (6a). By following a
procedure similar to that 4a, the reaction of (PPh )[Cp*W(S) (NPh)]
3) (0.31 g, 0.38 mmol) with RuCl (PPh (0.36 g, 0.38 mmol) in CH
CN (15 mL) gave Cp*W(NPh)(µ-S) RuCl(PPh (6a) as a green
): δ 7.30-6.98 (m, 30 H, PPh ),
6.86 (brt, 2 H, NPh), 6.67 (brt, 1 H, NPh), 6.17 (brd, 2 H, NPh), 1.88
2
1
31
8 H, PPh
3
1
6
D
6
3
9
4
H46OP
2
2
2
3 2
)
4
2
The following compounds were prepared according to the literature
(
2
)
3 3
3
-
1
0a
10b
procedures. (PPh
RuCl (PPh , RuClH(PPh
Synthesis of (PPh )[Cp*W(S)
10 mg, 0.15 mmol) was dissolved in CH
4
)[Cp*W(S)
,12 NaBArF
(NPh)] (3). (PPh
3
] (1),
(PPh
and [H(OEt
)[Cp*W(O)(S)
4
)[Cp*W(S)
2
(O)] (2),
2
3 2
)
18
)
3 3
1
2
3
)
3
4
2
)
2
]BArF
4
.
powder (0.23 g, 54%). H NMR (CDCl
3
3
4
2
4
2
] (2;
31
1
2
1
3
CN (15 mL) under nitrogen
(s, 15 H, Cp*). P{ H} NMR (CDCl ): δ 69.5 (d, J ) 30 Hz, PPh ),
3
PP
3
2
-1
atmosphere, to which PhNCO (17 mL, 0.16 mmol) was added with
stirring at 40 °C, and the reaction mixture was kept stirring for 2 h.
26.4 (d, J ) 30 Hz, PPh ). IR (KBr pellet): 1336 (s, νWdNPh) cm
.
PP
3
+
+
FAB-MS (CH Cl ): m/z 1135 ([Cp*W(NPh)(µ-S) RuCl(PPh ) ] ),
2
2
2
3 2
+
The CH
with hexane to give (PPh
3
CN was removed under vacuum, and the residue was washed
)[Cp*W(S) (NPh)] (3) as an orange powder
118 mg, 98%). H NMR (CD CN): δ 8.0-7.6 (m, 20 H, PPh ), 7.21-
.70 (m, 5 H, NPh), 1.99 (s, 15 H, Cp*). IR (KBr pellet): 1350 (s,
1100 ([Cp*W(NPh)(µ-S) Ru(PPh ) ]) ), 873 ([Cp*W(NPh)(µ-S) RuCl-
2
3 2
2
+
+
4
2
(PPh )] ), 838 ([Cp*W(NPh)(µ-S) RuPPh ]) ). Anal. Calcd for C H -
3
2
3
52 50
1
(
6
3
4
2 2
NP RuS W: C, 55.00; H, 4.44; N, 1.23; S, 5.65. Found: C, 55.00; H,
4.69; N, 1.30; S, 5.63.
-
1
WdNPh), 455, 434 (s, WdS) cm . ESI-MS (CH
3
CN): m/z 474
PW: C 59.04; H 4.95;
Synthesis of Cp*W(NPh)(µ-S) RuH(PPh ) (6b). The procedure
is similar to that of 4b. The reaction of (PPh )[Cp*W(S) (NPh)] (3)
4 2
2
3 2
-
2
([Cp*W(S) (NPh)] ). Anal. Calcd for C40
H
40NS
2
N 1.72; S 7.88 Found: C 58.27; H 5.16; N 1.76; S 7.85.
Synthesis of Cp*W(µ-S) RuCl(PPh (4a). A mixture of (PPh
Cp*W(S) ] (1) (0.37 g, 0.50 mmol) and RuCl (PPh (0.47 g, 0.49
mmol) in CH CN (60 mL) was stirred at room temperature for 4 h.
After removal of the solvent under vacuum, the black-brown residue
was washed with THF (20 mL) and CH CN (40 mL) to afford Cp*W-
µ-S) RuCl(PPh (4a) as a brown powder (0.41 g, 77%). X-ray quality
crystals were grown by layering hexane onto the CH Cl solution of
): δ 7.48-7.45 (m, 12 H,
), 7.10-7.06 (m, 12 H, PPh ), 2.10 (s,
5 H, Cp*). P{ H} NMR (CDCl ): δ 31.7 (s, PPh ). Anal. Calcd for
RuS W‚CH Cl : C, 48.61; H, 4.08; S, 8.28. Found: C,
8.29; H, 4.14, S, 8.54.
Synthesis of Cp*W(µ-S)
added to a mixture of (PPh )[Cp*W(S)
RuClH(PPh
(0.34 g, 0.42 mmol) with RuClH (PPh ) (0.39 g, 0.42 mmol) in CH -
3
3
3
3
3
)
2
4
)-
CN (10 mL) afford Cp*W(NPh)(µ-S)
2
RuH(PPh
3
)
2
(6b) as a brown
1
[
3
2
3
)
3
powder (0.35 g, 76%). H NMR (C
7.46-7.40 (m, 1 H, NPh), 6.98-6.94 (m, 2 H, NPh), 6.92-6.88 (m,
6 H, PPh ), 6.86-6.80 (m, 12 H, PPh ), 6.76-6.74 (m, 2 H, NPh),
1.79 (s, 15 H, Cp*), -10.81 (t, JPH ) 33 Hz, 1 H, Ru-H). P{ H}
6 6 3
D ): δ 7.72-7.68 (m, 12 H, PPh ),
3
3
3
2
31
1
3
-1
(
3
3
)
2
6 6 3
NMR (C D ): δ 69.3 (s, PPh ). IR (KBr pellet): 1348 (s, νWdNPh) cm
.
F
2
2
Formation of [Cp*W(OH)(µ-S) RuH(PPh ) ](BAr ) (7a) from
2
3
2
4
1
F
4
a at room temperature. H NMR (CDCl
3
2 4
5b, H gas, and NaBAr . A mixture of 5b (0.15 g, 0.14 mmol) and
NaBArF (0.13 g, 0.15 mmol) in CH Cl (10 mL) was stirred under H
PPh ), 7.23-7.20 (m, 6 H, PPh
3
3
3
4
2
2
2
3
1
1
1
C
4
3
3
atmosphere (1 atm) at room temperature for 1 h. The solution quickly
turned purple. After being centrifuged to remove NaCl, the solvent
46
H
45ClP
2
3
2
2
was removed under vacuum. The purple residue was washed with small
F
3
RuH(PPh
3
)
2
(4b). CH
3
CN (120 mL) was
2 3 2
amount of hexane to afford [Cp*W(OH)(µ-S) RuH(PPh ) ](BAr
4
) (7a)
as a purple powder (0.23 g, 84%). The NMR, IR, and ESI-MS spectra
were measured using this purple powder. X-ray quality crystals were
4
3
] (1) (1.21 g, 1.61 mmol) and
) (1.59 g, 1.56 mmol). The suspension was stirred at room
3 3
1
temperature for 1 day to yield brown precipitation. After decanting
brown solution off, the brown residue was extracted with toluene (80
grown by cooling an ether solution of 7a at -78 °C. H NMR (THF-
F
d
BAr
8
): δ 9.07 (brs, 1 H, WOH), 7.80 (br, 8 H, BAr
4
), 7.58 (br, 4 H,
F
2
mL), and centrifuged to remove PPh
in vacuo, the brown residue was washed with CH
afforded Cp*W(µ-S) RuH(PPh (4b) as a brown crystalline powder
1.35 g, 83%). X-ray quality crystals were grown by layering hexane
4
Cl. After removal of the solvent
4
) 7.4-7.1 (m, 30 H, PPh
3
), 1.99 (s, 15 H, Cp*), -3.37 (t, JPH
)
31
1
1
3
CN (30 mL) to
32 Hz, 1 H, RuH). P{ H} NMR (THF-d
(CDCl ), 7.50 (br, 4 H, BAr
): δ 7.70 (br, 8 H, BArF
30 H, PPh ), 1.93 (s, 15 H, Cp*), -1.70 (t, JPH ) 32 Hz, 1 H, RuH).
P{ H} NMR (CDCl ): δ 67.1 (s, PPh ). IR (KBr pellet): 3453 (m,
8
): δ 70.8 (s, PPh
3
). H NMR
F
)
2
3
4
4
) 7.4-7.1 (m,
3
3
2
(
3
1
31
1
onto the toluene solution of 4b at room temperature. H NMR
CDCl ): δ 7.53-7.49 (m, 12H, PPh ), 7.15-7.02 (m, 18 H, PPh ),
.06 (s, 15 H, Cp*), -10.47 (t, JPH ) 29 Hz, 1 H, RuH). P{ H}
3
3
-
1
(
2
3
3
3
ν
WO-H), 2019 (w, νRu-H) cm . ESI-MS (THF): m/z 1026 ([Cp*W-
2
31
1
+
(OH)(µ-S)
2
RuH(PPh
3
)
2
-H] ). Anal. Calcd for C78
H59BF24OP
2 2
RuS W‚
1
NMR (CDCl
3
): δ 57.3 (s, PPh
3
). H NMR (C
), 1.91 (s, 15 H, Cp*), -10.30
t, JPH ) 30 Hz, 1 H, RuH). P{ H} NMR (C ): δ 58.5 (s, PPh ).
6
D
6
): δ 7.88-7.85 (m,
4
C H
10O: C, 50.14; H, 3.54; S, 3.26. Found: C, 50.07; H, 3.68; S, 3.09.
](BArF
Formation of [Cp*W(NHPh)(µ-S) RuH(PPh ) (8) from
2 4
6b, H gas, and NaBAr . The procedure is analogous to that used for
1
(
2 H, PPh ), 7.00-6.94 (m, 18 H, PPh
3
3
2
)
3 2
4
2
31
1
F
6
D
6
3
7
986 J. AM. CHEM. SOC. VOL. 125, NO. 26, 2003
9

Heterolytic Cleavage of Dihydrogen
A R T I C L E S
Table 5. Crystal Data for Cp*W(µ-S)3RuCl(PPh3)2‚CH2Cl2 (4a‚CH2Cl2), Cp*W(µ-S)3RuH(PPh3)2 (4b), Cp*W(O)(µ-S)2RuCl(PPh3)2‚CH2Cl2
F
(
5a‚CH2Cl2), Cp*W(O)(µ-S)2RuCl(PPh3)2‚C6H5CH3 (5b‚C6H5CH3), [Cp*W(OH)(µ-S)2RuH(PPh3)2](BAr 4)‚2C4H10O (7a‚2C4H10O),
[
Cp*W(OH)(µ-S)2RuH(PPh3)2]OTf (7b), [Cp*W(µ-S)3RuL(PPh3)2](OTf) (L ) CH3CN (9), CO (10)), and
[
Cp*W(O)(µ-S)2Ru(CH3CN)(PPh3)2](OTf) (11b)
4
a•CH
2
Cl
2
4b
5a•CH
2
Cl
2
6 5 3
5b•C H CH
formula
C46H45ClP2S3RuW•CH2Cl2
1161.29
orthorhombic
Pbca (No. 61)
red
34.5808(3)
18.2206(1)
14.4798(1)
C46H46P2S3RuW
1041.92
triclinic
P 1h (No.2)
red
11.5969(8)
12.611(1)
16.3226(2)
84.380(1)
75.862(3)
65.3699(7)
2104.3(2)
2
C46H45ClP2S2ORuW•CH2Cl2
1145.23
orthorhombic
Pna21 (No.33)
green
23.7028(5)
14.8984(1)
12.9654(1)
C46H46P2S2ORuW•C6H5CH3
1118.00
triclinic
P 1h (No.2)
red
10.1719(5)
12.1015(7)
19.543(1)
87.3157(6)
88.1864(9)
76.985(1)
2339.6(2)
2
mol wt (g mol-1)
crystal system
space group
color of crystal
a (Å)
b (Å)
c (Å)
R (°)
â (°)
γ (°)
3
V (Å )
9123.47(10)
8
4578.52(8)
4
Z
R
Rw
GOF
0.027
0.052
1.81
0.020
0.022
1.00
0.026
0.042
2.02
0.035
0.055
1.89
7
a•2C
4
H
10
O
7b
9
10
11b
formula
C78H59F24BP2S2ORuW‚2C4H10O C47H47F3P2S3O4RuW C49H48F3NP2S4O3RuW C48H45F3P2S4O4RuW C49H48F3NP2S3O4RuW
mol wt (g mol-1) 2038.33
1175.93
triclinic
P 1h (No.2)
purple
1231.03
triclinic
P 1h (No.2)
red
1217.98
1214.97
crystal system
space group
color of crystal
a (Å)
b (Å)
c (Å)
triclinic
P 1h (No.2)
purple
monoclinic
P21/c (No.14)
orange
monoclinic
P21/n (No.14)
dark blue
13.929(1)
14.281(2)
23.637(3)
103.543(3)
104.860(1)
95.669(1)
4354.7(7)
2
9.2932(6)
13.7152(7)
18.4144(6)
104.7569(6)
95.1659(1)
91.219(1)
2258.0(2)
2
12.5670(6)
13.764(1)
14.728(1)
77.6218(6)
77.0646(5)
82.866(1)
2417.4(2)
2
14.857(2)
16.402(3)
22.9772(8)
12.9743(6)
24.498(2)
14.9406(2)
R (°)
â (°)
94.7078(8)
91.9160(3)
γ (°)
3
V (Å )
5580(1)
4
4746.2(3)
4
Z
R
Rw
GOF
0.058
0.069
1.60
0.042
0.054
2.20
0.028
0.051
1.91
0.075
0.091
4.71
0.028
0.036
2.04
a
R ) Σ||Fo| - |Fc||/Σ|Fo|, Rw ) [{Σw(|Fo| - |Fc|) }/ΣwFo ] , GOF ) [Σw(|Fo | - |Fc |) /(No - Np)]1/2, where No and Np denote the number of data
2
2 1/2
2
2 2
and parameters.
1
the synthesis of 7a. The reaction of Cp*W(NPh)(µ-S)
2
RuCl(PPh
(0.070 g, 0.079 mmol) under H
atmosphere at room temperature gave [Cp*W(NHPh)(µ-S) RuH(PPh ]-
) (8) as a dark-brown powder (0.148 g, 95%). H NMR (THF-
3
)
2
(6b)
d
8
): δ 68.9 (s, PPh
3
). H NMR (CDCl
), 1.96 (s, 15 H, Cp*), -4.81 (t, JPH ) 32
Hz, 1 H, RuH). 31P{ H} NMR (CDCl
): δ 66.4 (s, PPh ). IR (KBr
pellet): 2015 (w, νRu-H) cm-1. Anal. Calcd for C47
RuS W:
C, 48.00; H, 4.03; S, 8.18. Found: C, 48.23; H, 4.15; S, 8.22.
Anion exchange of [Cp*W(OH)(µ-S) RuH(PPh ) ](OTf) (7b) with
3
): δ 7.29-7.24 (m, 18 H, PPh
3
),
F
2
(0.090 g, 0.079 mmol) with NaBAr
4
2
7.14-7.11 (m, 12 H, PPh
3
1
2
)
3 2
3
3
BArF
): δ 7.80 (br, 8 H, BAr
PPh ), 6.9-6.7 (m, 5 H, NPh) 5.69 (brs, 1 H, NHPh), 1.74 (s, 15 H,
Cp*), -3.98 (t, JPH ) 32 Hz, 1H, RuH). P{ H} NMR (THF-d
1
H F O
47 3 4
P
2
(
d
4
3
F
F
8
4 4
), 7.58 (br, 4 H, BAr ) 7.4-7.0 (m, 30 H,
3
2
3 2
2
31
1
F
F
8
): δ
4 4
NaBAr . A THF (30 mL) solution of NaBAr (0.32 g, 0.36 mmol)
-
1
6
8.43 (s, PPh
Cl
for C84
Found: C, 50.97; H, 3.59; N, 0.79; S, 2.83.
Reaction of Cp*W(O)(µ-S) RuH(PPh
BArF
). A THF (5 mL) solution of [H(OEt
3
). IR (KBr pellet): 3303 (m, νN-H) cm . ESI-MS (CH
2
-
was added to a THF (20 mL) solution of 7b prepared from the reaction
of 5b (0.37 g, 0.36 mmol) with TfOH in situ at room temperature, and
the reaction mixture was stirred for 20 min. Solvent was removed in
vacuo, and the purple residue was extracted with CH Cl . After being
centrifuged to remove NaCl, the purple solution was evaporated under
vacuum. The purple residue was washed with hexane to yield 7a as a
purple powder (0.60 g, 88%).
+
2
): m/z 1103 ([Cp*W(NHPh)(µ-S)
RuS
2
RuH(PPh
3
)
2
+H] ). Anal. Calcd
H
64BF24NP
2
2
W: C, 51.34; H, 3.28; N, 0.71; S, 3.26.
2
2
2
3
)
2
(5b) with [H(OEt
](BAr
)
2 2
]-
F
(
4
2
)
2
4
) (0.096 g, 0.095
mmol) was added to a solution of 5b (0.10 g, 0.10 mmol) in THF (10
mL) with stirring at room temperature. The solution immediately turned
purple and was stirred for 2 h. Solvent was removed under vacuum,
and the purple residue was washed with a small amount of hexane to
afford 7a as a purple powder (0.19 g, 97%).
Formation of [Cp*W(µ-S) Ru(CH CN)(PPh ) ](OTf) (9) from 4b,
TfOH, and CH CN. Addition of TfOH (0.28 mmol) to a solution of
3
3
3 2
3
4b (0.29 g, 0.28 mmol) in THF (40 mL) led to evolution of H . The
2
mixture was stirred at room temperature for 2 h, and centrifuged. After
removal of the solvent under vacuum, the brown residue was dissolved
2 3 2
Formation of [Cp*W(OH)(µ-S) RuH(PPh ) ](OTf) (7b) from 5b
and TfOH. Addition of TfOH (0.17 mmol) to a THF (20 mL) solution
of 5b (0.17 g, 0.17 mmol) formed a purple solution. The mixture was
stirred at room temperature for 2.5 h. After removal of a solvent in
vacuo, the purple residue was extracted with DME (3 mL). Then
layering ether and hexane onto DME purple solution yields [Cp*W-
in CH
1 h. After removal of the solvent in vacuo, the brown residue was
washed with DME (2 mL) to afford [Cp*W(µ-S) Ru(CH CN)(PPh ]-
(OTf) (9) as a brown crystalline powder (0.30 g, 89%). X-ray quality
crystals were grown by layering ether onto the DME/CH CN solution
CN): δ 7.44-7.40 (m, 18 H,
), 2.19 (s, 15 H, Cp*). 1.97 (s, 3 H,
CN). 31P{ H} NMR (CD
CN): δ 37.5 (s, PPh ). IR (Nujol):
2210 (w, νCH3CN) cm . ESI-MS (CH CN): m/z 1082 ([Cp*W(µ-S) Ru-
3
CN (10 mL). The mixture was stirred at room temperature for
3
3
3 2
)
3
1
(
OH)(µ-S)
2
RuH(PPh
H NMR (THF-d ): δ 10.8 (brs, 1 H, WOH), 7.32-7.28 (m, 12 H,
PPh ), 7.24-7.21 (m, 6 H, PPh ), 7.12-7.09 (m, 12 H, PPh ), 1.95 (s,
5 H, Cp*), -5.96 (t, JPH ) 32 Hz, 1 H, RuH). P{ H} NMR (THF-
3
)
2
](OTf) (7b) as dark purple crystals (0.17 g, 87%).
of 9 at room temperature. H NMR (CD
PPh ), 7.31-7.28 (m, 12 H, PPh
free CH
3
1
8
3
3
1
3
3
3
3
3
3
2
31
1
-1
1
3
3
J. AM. CHEM. SOC.
9
VOL. 125, NO. 26, 2003 7987

A R T I C L E S
Ohki et al.
(
C
CH
3
CN)(PPh
NO
3
)
2
]+), 1041 ([Cp*W(µ-S)
3
Ru(PPh
3
)
2
]+). Anal. Calcd for
from the reaction between 5b (0.36 g, 0.35 mmol) and TfOH in situ
was added CH CN (3 mL) at room temperature. Evolution of H was
3 2
49
H
48
F
3
3
P
2
RuS W: C, 47.80; H, 3.93; N, 1.14; S, 10.42. Found:
4
C, 47.52; H, 4.00; N, 1.14; S, 11.08.
Formation of [Cp*W(µ-S) Ru(CO)(PPh
TfOH, and CO. After the reaction mixture of TfOH (0.35 mmol) and
b (0.36 g, 0.35 mmol) in THF (30 mL) was stirred at room temperature
for 30 min, where generation of H was noticed, CO (1 atm) was
introduced and the solution was stirred for 2 h. The THF solution was
concentrated, and addition of ether (50 mL) gave rise to an orange
precipitation. After decantation, the orange solid was washed with ether
observed, and the resulting yellow solution was stirred for 2 h. The
solvent was removed in vacuo, and yellow residue was washed with
3
3 2
) ](OTf) (10) from 4b,
2 3 3 2
ether and toluene to give [Cp*W(O)(µ-S) Ru(CH CN)(PPh ) ](OTf)
4
(11b) as a blue powder (0.40 g, 95%). X-ray quality crystals were grown
1
2
from ether/THF. H NMR (CDCl
3
): δ 7.46-6.88 (m, 30 H, PPh
3
),
1
2.30 (s, 3 H, CH
3
CN), 1.89 (s, 15 H, Cp*). 31P{ H} NMR (CDCl
68.4 (d, JPP ) 26 Hz, PPh
2277 (w, νCH3CN), 899 (s, νWdO) cm . ESI-MS (CH
3
): δ
). IR (Nujol):
): m/z 1066
2
2
3
), 32.7 (d, JPP ) 26 Hz, PPh
3
-
1
2
Cl
2
+
3
to afford [Cp*W(µ-S) Ru(CO)(PPh
3
2
) ](OTf) (10) as a orange powder
([Cp*W(O)(µ-S)
NO RuS
2
Ru(CH
3
CN)(PPh
3
)
2
] ). Anal. Calcd for C49
H
48
F
3
-
(
0.19 g, 46%). X-ray quality crystals were grown from hexane/THF at
4
P
2
2
W: C, 48.44; H, 3.98; N, 1.15; S, 7.92. Found: C, 48.37;
1
room temperature. H NMR (CDCl
7
δ 37.2 (s, PPh
3
): δ 7.44-7.38 (m, 6 H, PPh
3
),
H, 4.12; N, 1.29; S, 7.88.
), 2.27 (s, 15 H, Cp*). 3 P{ H} NMR (CDCl
1
1
):
CN):
.3-7.2 (m, 24 H, PPh
3
3
X-ray Crystal Structure Determination. Crystal data and refine-
ment parameters for the structurally characterized complexes are
summarized in Table 5. Single crystals were coated with oil (Immersion
Oil, type B: Code 1248, Cargille Laboratories, Inc.) and mounted on
loops. Diffraction data were collected at -80 °C (for 4a, b, 5a, b, 7b,
9, 10, and 11b) or -100 °C (for 7a) under a cold nitrogen stream on
a Rigaku AFC7 equipped with a rotating anode and a MSC/ADSC
Quantum 1 CCD detector (for 7a, b, 10, and 11b), or on a Rigaku
AFC5 equipped with an ADSC CCD detector (for 4a, b, 5a, b, and 9)
by using graphite-monochromated Mo KR radiation (λ ) 0.710690
Å). Four preliminary data frames were measured at 0.5° increments of
ω, to assess the crystal quality and preliminary unit cell parameters.
The intensity images were also measured at 0.5° intervals of ω. The
frame data were integrated using an MSC d*TREK program package,
and the data sets were corrected for absorption using a REQAB
program. All calculations were performed with a TEXSAN program
package. All structures were solved by direct methods. The remaining
heavy atoms were found in subsequent Fourier maps, and the structures
were refined by full-matrix least-squares. Anisotropic refinement was
applied to all non-hydrogen atoms, except for the disordered OTf anion
in 7b were isotropically refined. The OTf anion in 7b is disordered
over two positions, with occupancy factors of 50:50. The hydrogen
atoms bound to Ru in 4b, 5b, 7a, and 7b were located in the Fourier
maps, and were refined isotropically, while the other hydrogen atoms
were put at calculated positions. Additional data are available as
Supporting Information.
). IR (Nujol): 1990 (w, νCO) cm- . ESI-MS (CH
1
3
3
+
m/z 1069 ([Cp*W(µ-S)
NO RuS
S, 10.68.
Reaction of [Cp*W(OH)(µ-S)
N. A resealable NMR tube was charged with a THF-d
solution of 7a (0.039 g, 0.021 mmol), and one drop of Et N was added.
3
Ru(CO)(PPh
3
)
2
] ). Anal. Calcd for C48
45
H F
3
-
4
P
2
4
W: C, 47.33; H, 3.72; S, 10.53. Found: C, 46.81; H, 4.05;
](BArF
) (7a) with
(0.6 mL)
2
RuH(PPh
3
)
2
4
Et
3
8
3
The NMR tube was shaken repeatedly at room temperature, and
immediately placed in the NMR spectrometer. The spectrum showed
a quantitative formation of Cp*W(O)(µ-S)
Reaction of [Cp*W(OH)(µ-S) RuH(PPh
Cp*W(µ-S) RuH(PPh (4b). A resaelable NMR tube containing the
reaction mixture of 7a (0.022 g, 0.012 mmol) and 4b (0.012 g, 0.012
mmol) in THF-d (0.6 mL) was shaken, and was set on an NMR
spectrometer. Generation of H and a quantitative amount of Cp*W-
O)(µ-S) RuH(PPh
(5b) was observed in the 1H NMR spectrum
together with uncharacterizable signals. Then, a small amount of CH
CN was added to the solution. The NMR tube was shaken and was
2
RuH(PPh
3 2
) (5b).
F
2
3
)
2
](BAr
4
) (7a) with
3
3 2
)
8
2
(
2
3 2
)
3
-
1
31
1
subjected for the NMR measurement. The resulting H and P { H}
NMR spectra revealed a quantitative formation of [Cp*W(µ-S) Ru-
3
F
(
CH
Formation of [Cp*W(O)(µ-S)
from 7a and CH CN. To an ether (5 mL) solution of 7a (0.122 g,
.065 mmol) was added CH CN (0.1 mL) at room temperature.
was observed, and the resulting yellow solution was
3
CN)(PPh
3
)
2
](BAr
4
) (9) and 5b.
2
Ru(CH
3 3 2 4
CN)(PPh ) ) (11a)
](BArF
3
0
3
Evolution of H
2
stirred for 10 min. The solvent was removed in vacuo, and the residue
was washed with hexane to give [Cp*W(O)(µ-S) Ru(CH CN)(PPh ]-
) (11a) as a blue powder (0.118 g, 95%). H NMR (CDCl ): δ
), 7.4-6.8 (m, 30 H, PPh ),
): δ
). IR (Nujol):
): m/z 1066
2
1
3
3
)
2
Acknowledgment. This work was supported by Grant-in-
Aid for Scientific Research on Priority Areas (No. 14078101,
4078211 “Reaction Control of Dynamic Complexes”) from
Ministry of Education, Science, Sports, and Culture, Japan.
(
BArF
4
3
.70 (br, 8 H, BArF
), 7.52 (br, 4 H, BAr
F
7
1
6
2
4
4
3
1
3
1
1
.91 (s, 3 H, CH CN), 1.90 (s, 15 H, Cp*). P{ H} NMR (CDCl
3
3
2
2
8.7 (d, JPP ) 26 Hz, PPh
3
), 32.8 (d, JPP ) 26 Hz, PPh
279 (w, νCH3CN), 912 (s, νWdO) cm . ESI-MS (CH
3
-
1
2
Cl
2
Supporting Information Available: X-ray crystallographic
information files (CIF) for the structures of 4a, 4b, 5a, 5b, 7a,
b, 9, 10, and 11b. This material is available free of charge via
+
(
[Cp*W(O)(µ-S)
2
Ru(CH
3
CN)(PPh
3
)
2
] ). Anal. Calcd for C80H60BF24
-
2 2
NOP RuS W: C, 49.81; H, 3.13; N, 0.73; S, 3.32. Found: C, 49.49;
H, 3.30; N, 0.85; S, 3.22.
Formation of [Cp*W(O)(µ-S) Ru(CH CN)(PPh ) ](OTf) (11b)
2 3 3 2
7
the World Wide Web at http://pubs.acs.org.
3
from 7b and CH CN. To a THF (50 mL) solution of 7b prepared
JA029941X
7988 J. AM. CHEM. SOC.
9
VOL. 125, NO. 26, 2003