Reactivity of the bis(dihydrogen) complex [RuH2(η2-H2)2 (PCy3)2] toward S-heteroaromatic compounds. Catalytic hydrogenation of thiophene

Article abstract of DOI:10.1021/om0304309

Room-temperature stoichiometric reaction of the bis(dihydrogen) complex [RuH₂(η²-H₂)₂ (PCy₃)₂] (1) with thiophene leads to the formation of a new complex that has been isolated and characterized as an η⁴-thioallyl complex [RuH(η⁴(S, C)-SC₄H₅)(PCy₃)₂] (2). This complex easily regenerates 1 upon treatment with dihydrogen and can be successfully used as a catalyst precursor in thiophene hydrogenation to 2,3,4,5-tetrahydrothiophene (THT). The reaction of 1 with 2-acetylthiophene leads to a regioselective 1,5-C-S bond splitting with formal hydrogenation of two double C≠C bonds and coordination of a new 2-hexen-2-olato-3-thiolato ligand in an η²(O,S) mode to form [RuH₂{η²(O,S)-C₆H₁₀OS} (PCy₃)₂] (3). The new complex 3 has been characterized by ¹H, ³¹P, and ¹³C NMR studies including ¹H DPFGSE TOCSY, 2D-¹H-¹H{³¹P} COSY DQF, and the correlated ¹³C-¹H HMQC LR spectra. The solid state molecular structure of 3 has been unequivocally determined by single-crystal X-ray structure analysis. The bis(dihydrogen) complex 1 is an effective catalyst precursor for the homogeneous hydrogenation of thiophene (T) to 2,3,4,5-tetrahydrothiophene (THT), 2-methylthiophene (2-MeT) to 2-methyltetrahydrothiophene (2-MeTHT), 2-acetylthiophene (2-AcT) to 1-(2-thienyl)ethanol (1-(2-Tyl)E), 2-thiophenecarboxaldehyde (2-TA) to 2-thiophenemethanol (2-TM), and benzo[b]thiophene (BT) to 2,3-dihydrobenzo[b]thiophene (DHBT) under mild conditions (80°C, 3 bar H₂). Dibenzo[b,d]thiophene (DBT) is not reduced under these conditions due to the formation of the S-coordinated dihydrogen complex [RuH₂(η²-H₂){η¹(S)- C₁₂H₈S}(PCy₃)₂] (4).

Full text of DOI:10.1021/om0304309

Organometallics 2003, 22, 4803-4809
4803
Rea ctivity of th e Bis(d ih yd r ogen ) Com p lex
[Ru H2(η2-H2)2(P Cy3)2] tow a r d S-Heter oa r om a tic
Com p ou n d s. Ca ta lytic Hyd r ogen a tion of Th iop h en e
Andrzej F. Borowski,*,† Sylviane Sabo-Etienne,*,‡ Bruno Donnadieu,‡ and
Bruno Chaudret‡
Institute of Coal Chemistry, Polish Academy of Sciences, 5 Sowinskiego Street,
44-121 Gliwice, Poland, and Laboratoire de Chimie de Coordination du CNRS,
205 Route de Narbonne, 31 077 Toulouse Cedex 04, France
Received J une 4, 2003
Room-temperature stoichiometric reaction of the bis(dihydrogen) complex [RuH2(η2-H2)2-
(PCy3)2] (1) with thiophene leads to the formation of a new complex that has been isolated
and characterized as an η4-thioallyl complex [RuH(η4(S,C)-SC4H5)(PCy3)2] (2). This complex
easily regenerates 1 upon treatment with dihydrogen and can be successfully used as a
catalyst precursor in thiophene hydrogenation to 2,3,4,5-tetrahydrothiophene (THT). The
reaction of 1 with 2-acetylthiophene leads to a regioselective 1,5-C-S bond splitting with
formal hydrogenation of two double CdC bonds and coordination of a new 2-hexen-2-olato-
3-thiolato ligand in an η2(O,S) mode to form [RuH2{η2(O,S)-C6H10OS}(PCy3)2] (3). The new
1
1
complex 3 has been characterized by H, 31P, and 13C NMR studies including H DPFGSE
TOCSY, 2D-1H-1H{31P} COSY DQF, and the correlated 13C-1H HMQC LR spectra. The
solid state molecular structure of 3 has been unequivocally determined by single-crystal
X-ray structure analysis. The bis(dihydrogen) complex 1 is an effective catalyst precursor
for the homogeneous hydrogenation of thiophene (T) to 2,3,4,5-tetrahydrothiophene (THT),
2-methylthiophene (2-MeT) to 2-methyltetrahydrothiophene (2-MeTHT), 2-acetylthiophene
(2-AcT) to 1-(2-thienyl)ethanol (1-(2-Tyl)E), 2-thiophenecarboxaldehyde (2-TA) to 2-thiophen-
emethanol (2-TM), and benzo[b]thiophene (BT) to 2,3-dihydrobenzo[b]thiophene (DHBT)
under mild conditions (80 °C, 3 bar H2). Dibenzo[b,d]thiophene (DBT) is not reduced under
these conditions due to the formation of the S-coordinated dihydrogen complex [RuH2(η2-
H2){η1(S)-C12H8S}(PCy3)2] (4).
In tr od u ction
sembling sulfur contaminants in petroleum.2 Soluble
metal complexes serve as very good models for studying
catalytic reactions occurring during the course of HDS
processes, as mechanistic information can be readily
achieved by the use of spectroscopic and other analytical
methods. Many homogeneous systems based on transi-
tion metal complexes have been studied in hydrogena-
tion reactions of sulfur-containing heteroaromatics.3
There are numerous reports on the reactivity of sulfur-
containing heteroaromatics with metal complexes that
lead to the formation of products bearing coordinated
heteroaromatic ligands.2b,4 Reports on C-S bond scis-
Catalytic hydrodesulfurization (HDS) of petroleum
and other fossil fuel feedstock is an important industrial
process employed to remove sulfur as H2S through
reaction with dihydrogen. While most of the sulfur-
containing molecules (especially saturated cyclic thio-
ethers and thiols) are susceptible to HDS, molecules
containing thiophene rings, especially those containing
substituted benzothiophenes and dibenzothiophenes,
are resistant to desulfurization. As a consequence, these
species constitute the major pollutants in petroleum-
and coal-derived fuels, contributing significantly to acid
rain problems through formation of sulfur oxides (SOx)
upon combustion. HDS represents one of the largest
volume industrial processes based on transition metal
catalysis and is also aimed at preventing catalyst
poisoning both in refinement processes and in automo-
biles.1
(2) (a) Sa´nchez-Delgado, R. A. Organometallic Modeling of the
Hydrodesulfurization and Hydrodenitrogenation Reactions; Kluwer
Academic: Dordrecht, The Netherlands, 2002. (b) Bianchini, C.; Meli,
A. Acc. Chem. Res. 1998, 31, 109.
(3) Bianchini, C.; Meli, A. J . Chem. Soc., Dalton Trans. 1996, 801.
(4) (a) Bianchini, C.; Meli, A.; Peruzzini, M.; Vizza, F.; Herrera, V.;
Sa´nchez-Delgado, R. A. Organometallics 1994, 13, 721. (b) Lesch, D.
A.; Richardson, J . W., J r.; J acobson, R. A.; Angelici, R. A. J . Am. Chem.
Soc. 1984, 106, 2901. (c) Chaudret, B.; J alo´n, F.; Pe´rez-Manrique, M.;
Lahoz, F.; Plou, F. J .; Sa´nchez-Delgado, R. A. New J . Chem. 1990, 14,
331. (d) Dong, L.; Duckett, S. B.; Ohman, K. F.; J ones, W. D. J . Am.
Chem. Soc. 1992, 114, 151. (e) Sa´nchez-Delgado, R. A.; Herrera, V.;
Bianchini, C.; Masi, D.; Mealli, C. Inorg. Chem. 1993, 32, 3766. (f)
Morikita, T.; Hirano, M.; Sasaki, A.; Komiya, S. Inorg. Chim. Acta
1999, 291, 341. (g) Reynolds, M. A.; Guzei, I. A.; Logsdon, B. C.;
Thomas, L. M.; J acobson, R. A.; Angelici, R. A. Organometallics 1999,
18, 4075. (h) Bayo´n, J . C.; Claver, C.; Masdeu-Bulto´, A. M. Coord.
Chem. Rev. 1999, 193-195, 73.
The complex chemical composition of crude oil and
the difficulty in studying its HDS catalysis have led to
the examination of model compounds structurally re-
* Corresponding author. E-mail: sabo@lcc-toulouse.fr.
† Institute of Coal Chemistry, Polish Academy of Sciences.
‡ Laboratoire de Chimie de Coodination du CNRS.
(1) (a) Topsøe, H.; Clausen, B. S.; Massoth, F. E. Hydrotreating
Catalysis: Science and Technology; Springer-Verlag: Berlin, 1996. (b)
Rodriguez, J . A.; Hrbek, J . Acc. Chem. Res. 1999, 32, 719.
10.1021/om0304309 CCC: $25.00 © 2003 American Chemical Society
Publication on Web 10/11/2003

4804 Organometallics, Vol. 22, No. 23, 2003
Borowski et al.
Sch em e 1. Stoich iom etr ic Rea ction s of 1 w ith
Th iop h en e, 2-Acetylth iop h en e, a n d
Diben zo[b]th iop h en e
sion in heteroaromatic rings with formation of hetero-
metallacycles are quite numerous.5-11 Results of some
successful hydrogenolyses of the C-S bond7,8,12,13 and
of genuine homogeneous HDS13,14 and desulfurization
reactions9b,14,15 have been disclosed. In this context,
ruthenium complexes play a significant role, but reports
on their catalytic properties for hydrogenation of
thiophenic substrates are scarce.12b,16,17
Our catalyst precursor [RuH2(η2-H2)2(PCy3)2] (1) con-
taining two labile dihydrogen ligands18a,b has been
proven recently to be active and stable under mild
hydrogenation conditions in arene hydrogenation re-
actions.18c Moreover, we have very recently reported the
results of the reactivity of 1 with some selected nitrogen
heteroaromatic compounds and its catalytic activity
toward several N-heteroaromatics including hydrogena-
tion of acridine.18d We now wish to present our results
on the reactivity of 1 with some selected sulfur het-
eroaromatic compounds together with catalytic inves-
tigations on the hydrogenation of these S-aromatic
compounds using 1 as a catalyst precursor.
(5) J ones, W. D.; Vicic, D. A.; Chin, R. M.; Roache, J . H.; Myers, A.
W. Polyhedron 1997, 16, 3115.
(6) (a) J ones, W. D.; Dong, L. J . Am. Chem. Soc. 1991, 113, 559. (b)
Vicic, D. A.; J ones, W. D. J . Am. Chem. Soc. 1997, 119, 10855. (c) J ones,
W. D.; Chin, R. M.; Hoaglin, C. L. Organometallics 1999, 18, 1786. (d)
Vicic, D. A.; J ones, W. D. Organometallics 1999, 18, 134.
(7) (a) Bianchini, C.; Herrera, V.; J imenez, M. V.; Meli, A.; Sa´nchez-
Delgado, R. A.; Vizza, F. J . Am. Chem. Soc. 1995, 117, 8567. (b)
Bianchini, C.; Casares, J . A.; Meli, A.; Sernau, V.; Vizza, F.; Sa´nchez-
Delgado, R. A. Polyhedron 1997, 16, 3099. (c) Bianchini, C.; J imenez,
M. V.; Meli, A.; Vizza, F. Organometallics 1995, 14, 3196.
(8) (a) Dullaghan, C. A.; Zhang, X.; Greene, D. L.; Carpenter, G. B.;
Sweigart, D. A.; Camiletti, C.; Rajaseelan, E. Organometallics 1998,
17, 3316. (b) Li, H.; Carpenter, G. B.; Sweigart, D. A. Organometallics
2000, 19, 1823. (c) Yu, K.; Li, H.; Watson, E. J .; Virkaitis, K. L.;
Carpenter, G. B.; Sweigart, D. A. Organometallics 2001, 20, 3550. (d)
Kawano H.; Narimatsu, H.; Yamamoto, D.; Tanaka, K.; Hiraki, K.;
Onishi, O. Organometallics 2002, 21, 5526.
(9) (a) Garc´ıa, J . J .; Are´valo, A.; Capella, S.; Chehata, A.; Herna´ndez,
M.; Montiel, V.; Picazo, G.; del Rio, F.; Toscano, R. A.; Adams, H.;
Maitlis, P. M. Polyhedron 1997, 16, 3185. (b) Chehata, A.; Oviedo, A.;
Are´valo, A.; Berne`s, S.; Garc´ıa, J . J . Organometallics 2003, 22, 1585.
(c) Herna´ndez, M.; Miralrio, G.; Are´valo, A.; Berne`s, S.; Garc´ıa, J . J .;
Lopez, C.; Maitlis, P. M.; del Rio, F. Organometallics 2001, 20, 4061.
(10) Giner Planas, J .; Hirano, M.; Komiya, S. Chem. Commun. 1999,
1793.
Resu lts a n d Discu ssion
We will first describe the synthesis and characteriza-
tion of three new complexes 2-4 resulting from the
reactivity of the bis(dihydrogen) complex 1 with thio-
phene (T), 2-acetylthiophene (2-Act), and dibenzo[b,d]-
thiophene (DBT), respectively. The reactions are de-
picted in Scheme 1. We will then report our results on
the catalytic activity of 1 for hydrogenation of T, 2-AcT,
and DBT, as well as 2-methylthiophene (2-MeT),
2-thiophenecarboxaldehyde (2-TA), and benzo[b]thio-
phene (BT). The role of 2-4 in the catalytic cycle will
also be examined.
(11) (a) Matsubare, K.; Okamura, R.; Tanaka, M.; Suzuki, H. J . Am.
Chem. Soc. 1998, 120, 1108. (b) Churhill, D. G.; Bridgewater, B. M.;
Parkin, G. J . Am. Chem. Soc. 2000, 122, 178. (c) Palmer, M. S.; Harris,
S. Organometallics 2000, 19, 2114.
Rea ction of 1 w ith Th iop h en e (T). P r ep a r a tion
of [Ru H(η4(S,C)-SC4H5)(P Cy3)2] (2). The reaction of
1 with 2 equiv of thiophene (T) in pentane leads to the
formation of a beige solid analyzed as [RuH(η4(S,C)-
SC4H5)(PCy3)2] (2). This complex is formulated as a
neutral ruthenium(II) complex coordinating one hy-
dride, two cis tricyclohexylphosphines, and a thioallyl
ligand bound in an η4(S,C) fashion (see Scheme 1). The
hydride is characterized in the 1H NMR spectrum (C6D6,
293 K) by a doublet of doublets at δ -20.90 as a result
of a coupling with two nonequivalent phosphorus nuclei
(J P-H ) 28 and 35 Hz). This signal is of equal intensity
with five other signals at low field characterizing the
thioallyl ligand. Three broad signals at δ 5.56, 5.31, and
2.71 are assigned to the allylic moiety, whereas a virtual
triplet at δ 4.27 and a doublet at δ 3.73 are attributed
to the methylene protons (J H-H ) 9 Hz). The triplet at
δ 4.27 is the only resonance showing an appreciable
coupling to phosphorus (J P-H ) 9 Hz). It is transformed
into a doublet upon phosphorus decoupling. The 31P-
(12) (a) Bianchini, C.; Masi, D.; Meli, A.; Peruzzini, M.; Vizza, F.;
Zanobini, F. Organometallics 1998, 17, 2495. (b) Bianchini, C.; Meli,
A.; Moneti, S.; Vizza, F. Organometallics 1998, 17, 2636.
(13) Zhang, X.; Dullaghan, C. A.; Watson, E. J .; Carpenter, G. B.;
Sweigart, D. A. Organometallics 1998, 17, 2067.
(14) (a) Rondon, D.; Delbeau, J .; He, X.-D.; Sabo-Etienne, S.;
Chaudret, B. J . Chem. Soc., Dalton Trans. 1994, 1895. (b) Bianchini,
C.; J ime´nez, M. V.; Meli, A.; Moneti, S.; Vizza, F.; Herrera, V.; Sa´nchez-
Delgado, R. A. Organometallics 1995, 14, 2342. (c) Vicic, D. A.; J ones,
W. D. Organometallics 1997, 16, 1912. (d) Vicic, D. A.; J ones, W. D.
Organometallics 1998, 17, 3411. (e) Li, H.; Yu, K.; Watson, E. J .;
Virkaitis, K. L.; Carpenter, G. B.; Sweigart, D. A. Organometallics
2002, 20, 1262.
(15) Vicic, D. A.; J ones, W. D. J . Am. Chem. Soc. 1999, 121, 7606.
(16) Bianchini, C.; Meli, A.; Moneti, S.; Oberhauser, W.; Vizza, F.;
Herrera, V.; Fuentes, A.; Sa´nchez-Delgado, R. A. J . Am. Chem. Soc.
1999, 121, 7071.
(17) (a) Sa´nchez-Delgado, R. A.; Gonza´lez, E. Polyhedron 1989, 8,
1431. (b) Fish, R. H.; Tan, J . L.; Thormodsen, A. D. Organometallics
1985, 4, 1743.
(18) (a) Sabo-Etienne, S.; Chaudret, B. Coord. Chem. Rev. 1998,
170-180, 381. (b) Borowski, A. F.; Donnadieu, B.; Daran. J .-C.; Sabo-
Etienne, S.; Chaudret, B. Chem. Commun. 2000, 543, 1697. (c)
Borowski, A. F.; Sabo-Etienne, S.; Chaudret, B. J . Mol. Catal. A: Chem.
2001, 174, 69. (d) Borowski, A. F.; Sabo-Etienne, S.; Donnadieu, B.;
Chaudret, B. Organometallics 2003, 22, 1630.

Catalytic Hydrogenation of Thiophene
Organometallics, Vol. 22, No. 23, 2003 4805
{1H} NMR spectrum (293 K) shows two broad signals
at δ 61.7 and 53.0.
A few η4-thioallyl complexes have been previously
reported in the literature. In particular, the dihydride
rhenium complex [ReH2(η4-SC4H5)(PPh3)2] was obtained
by reaction of thiophene with the polyhydride [ReH7-
(PPh3)2] in the presence of 3,3-dimethyl-1-butene.19 In
our system, it is noteworthy that reaction was observed
in the absence of any hydrogen acceptor. A mechanism
involving initial coordination of T, as an η4-diene, to an
unsaturated metal center followed by an intramolecular
hydrogenation to form the S-bound thioallyl complex has
been postulated by J ones et al. for the rhenium com-
plex.19 A similar pathway was also invoked by Rauch-
fuss et al. for a ruthenium complex20 and by Bianchini
et al. for an iridium one.4a It seems thus reasonable to
believe that formation of 2 in the reaction of thiophene
with 1 may proceed through a similar mechanism.
Interestingly, bubbling dihydrogen through a C6D6
solution of 2 in an NMR tube restores 1, characterized
by 1H and 31P NMR data. Removal of the thioallyl ligand
from the coordination sphere of the metal leads to free
tetrahydrothiophene (THT) characterized by a broad
F igu r e 1. Selected region of the 1H-1H{31P} COSY
spectrum of [RuH2{η2(O,S)-C6H10OS}(PCy3)2] (3) (C6D6, 293
K) showing H1, H4, H5, and H6 correlations.
1
triplet at δ 2.66 in the H NMR spectrum assigned to
the four H2,5 of THT, the second signal being hidden by
the intense signals of PCy3 protons resonating between
δ 1 and 2.5.
R ea ct ion of 1 w it h 2-Acet ylt h iop h en e (2-AcT).
Syn th esis of [Ru H2{η2(O,S)-C6H10OS}(P Cy3)2] (3).
Our findings that T is readily reduced to THT in the
process catalyzed by 1 (vide infra), along with the fact
that electron-withdrawing substituents at the 2 or 3
position of thiophene are known to facilitate the C-S
bond cleavage,7c,9,10 led us to investigate the reaction of
2-acetylthiophene (2-AcT) with 1, to achieve hydro-
genolysis of the C-S bond. Reaction of 1 with 1 equiv
of 2-AcT produces a red solid analyzed as [RuH2{η2-
(O,S)-C6H10OS}(PCy3)2] (3) (see Scheme 1). The NMR
spectra and a single-crystal X-ray analysis allow the
formulation of the complex as a dihydride five-mem-
1
bered metallacycle with an O,S-bound ligand. The H
NMR spectrum of 3 in C6D6 reveals a high-field reso-
nance triplet at δ -10.37 (J P-H ) 33 Hz). The 31P{1H}
NMR spectrum shows a singlet at δ 82.9 that trans-
forms into a triplet (J P-H ) 33 Hz) upon selective
decoupling of the PCy3 protons, in agreement with two
hydrides coupled to two equivalent phosphorus atoms.
Apart from the multiplets between δ 1.8 and 2.4, typical
for PCy3 protons, four other signals are present in the
F igu r e 2. Selected region of the 13C-1H HMQC LR
spectrum of [RuH2{η2(O,S)-C6H10OS}(PCy3)2] (3) (d8-
toluene, 293 K) showing in particular long-range correla-
tions of C2 with H1 and H4 and of C3 with H1, H4, and H5.
signals in the region of methyl carbon resonances. The
signal at δ 13.9 has been assigned to the terminal C6
carbon of the aliphatic chain, while the lower field
resonance signal (δ 21.7) belongs to the resonance of the
methyl carbon (C1) adjacent to the carbon atom bound
to the oxygen. The two remaining aliphatic carbons
resonate at δ 26.1 and 37.7, the latter being attributed
to the signal of the methylene carbon (C4) bound to the
alkene carbon. The two alkene carbon atoms show
resonance signals at δ 121.4 and 167.3, the former
carbon atom (C3) being bound to the sulfur atom. This
assignment has been supported by a 13C-1H HMQC LR
experiment (see Figure 2).
1
low-field region of the H NMR spectrum. The assign-
ment was established by 1H-1H{31P} COSY (see Figure
1) and 1H TOCSY experiments. The 1H{31P} NMR
spectrum reveals the presence of two methyl groups at
different chemical environment. A triplet at δ 1.16
belongs to a terminal methyl group of an aliphatic chain,
while the singlet at δ 2.65 corresponds to a methyl group
linked to a carbon bound to an oxygen and an alkene
carbon atom. Two methylene ligands resonate as a
triplet at δ 3.16 (J H-H ) 7.1 Hz) and as a multiplet at
δ 2.10 (partly obscured by the signals of PCy3 protons).
The 13C{1H} NMR spectrum of 3 in C6D6 exhibits two
Crystals of 3 suitable for an X-ray diffraction study
(Table 1) were obtained from acetone solutions. The
molecular structure is depicted in Figure 3. A few
(19) Rosini, G. P.; J ones, W. D. J . Am. Chem. Soc. 1992, 114, 10767.
(20) Luo, S.; Rauchfuss, T. B.; Wilson, S. R. J . Am. Chem. Soc. 1992,
114, 8515.

4806 Organometallics, Vol. 22, No. 23, 2003
Borowski et al.
F igu r e 4. Partial molecular structure of 3 showing the
trigonal prism.
a higher value is obtained (116.53(7)°). The C(3)-S and
C(2)-O distances of 1.735(7) and 1.363(8) Å, respec-
tively, are typical for interatomic distances between sp2
carbons bound to sulfur and oxygen atoms.23 The
shortest carbon-carbon distance of 1.336(10) Å points
toward a double C(2)dC(3) bond. These data indicate
that the delocalization within the metallacycle is very
limited, if it exists at all. Delocalization of RC(S)-C(S)R
and -C(O)-C(O)- bonds and distortion from ideal
trigonal prismatic and antiprismatic structures have
been mentioned to occur in transition metal chelate
complexes coordinating structurally analogous 1,2-dithi-
olene and tropolonate type ligands.24 In such a case,
C-O bond lengths are much shorter (1.308 Å in a cobalt
complex coordinating 3-hydroxy-4-pyridinone), and de-
localization is also evidenced by the elongation of the
C-C bond (up to 1.412 Å, a value lying between a single
C-C and a double CdC bond).25 The Ru-O interatomic
distance of 2.033(5) Å in our complex 3 is similar to that
reported in a ruthenium phenoxide complex (Ru-O
1.982 Å)26 and in another ruthenium complex coordinat-
ing a carboxylato fragment through only one C-O bond
(Ru-O 2.012 Å).27 The distances between the carbon
atoms in the aliphatic chain of 1.505 Å (average) and
the C-C-C bond angles of 114° are typical for that kind
of bonding.28 The shortest C-C single bond of 1.483-
(11) Å, localized between the methyl carbon C(1) and
the alkene carbon C(2), is similar to that found in a
ruthenium butadiene thiolate complex (1.46 Å).29a
In line with the above results, the reaction of 2-AcT
with [Ru(η4-COD)(η6-COT)] (the precursor used for the
synthesis of 1 in the presence of depe (depe ) 1,2-bis-
(diethylphosphino)ethane), studied by Komiya et al.,
leads also to a regioselective 1,5-insertion into the C-S
bond.10 However in that case, the formation of a thiaru-
F igu r e 3. Molecular structure of [RuH2{η2(O,S)-C6H10
-
OS}(PCy3)2] (3). Selected bond lengths (Å) and angles
(deg): Ru-O 2.033(5); Ru-S 2.281(2); Ru-P1 2.2930(18);
Ru-P2 2.2976(18); Ru-H1 1.72(5); Ru-H2 1.73(5); S-C3
1.735(7); O-C2 1.363(8); C2-C3 1.336(10); C1-C2 1.483-
(11); C3-C4 1.509(9); C4-C5 1.490(11); C5-C6 1.515(10);
O-Ru-S 81.44(14); P1-Ru-P2 116.53(7); H1-Ru-H2
103(3); P1-Ru-H1 63(2); P2-Ru-H2 74(2).
Ta ble 1. Cr ysta l Da ta for
[Ru H2{η2(O,S)-C6H10OS}(P Cy3)2] (3)
formula
C42H78OP2SRu
fw
794.11
cryst syst
monoclinic
P21/c
4, 1.229
0.518
space group
Z, calcd density, Mg/m3
abs coeff, mm-1
F(000)
1712
a, Å
b, Å
c, Å
9.9403(7)
43.1427(35)
10.0934(6)
97.576(8)
4290.8(8)
180(2)
â, deg
V, Å3
temp, K
no. of data/restraints/params
goodness of fit on F2
R1 [I > 2σ(I)]
wR2 [I > 2σ(I)]
R1 all data
5763/13/451
0.904
0.0504
0.0930
0.1173
wR2 all data
0.1142
0.594 and -0.494
largest diff peak and hole, e‚Å-3
complexes containing such a ligand coordinated in an
η2 mode by a sulfur and an oxygen bound to the same
CdC function are known, and one crystal structure of
a platinum complex was previously reported but with
a selenium in place of sulfur.21 The complex adopts a
six-coordinate geometry in which the ligands lie in the
vertexes of a slightly twisted trigonal prism, which is
depicted in Figure 4. The central metal atom bound to
a sulfur atom (Ru-S 2.281(2) Å) and to an oxygen atom
(Ru-O 2.033 (5) Å) constitutes an element of a five-
membered ring that includes as well the C(3)-S, C(2)-
O, and C(2)-C(3) bonds. A cis arrangement has been
found for the two PCy3 ligands. This cis position is rare
for such bulky phosphines but has been previously
observed in a family of bis(silane)ruthenium com-
plexes.22 It should be noted that in that case the
P-Ru-P angle was always close to 108°, whereas in 3,
(22) Delpech, F.; Sabo-Etienne, S.; Daran, J .-C.; Chaudret, B.;
Hussein, K.; Marsden, C. J .; Barthelat, J .-C. J . Am. Chem. Soc. 1999,
121, 6668.
(23) March, J . Advanced Organic Chemistry, Mechanisms and
Structure, 4th ed.; J . Wiley and Sons: New York, 1992; p 21
(24) Cotton, F. A.; Wilkinson, G. Advanced Inorganic Chemistry, 5th
ed.; Wiley-Interscience: New York, 1992; p 14.
(25) Burgees, J .; Fawcett, J .; Llewellyn, M. A.; Parsons, S. A.; Russel,
D. R. Transition Met. Chem. 2000, 25, 541.
(26) Mondal, B.; Chakraborty, S.; Munshi, P.; Walawalkar, M. G.;
Lahiri, G. K. J . Chem. Soc., Dalton Trans. 2000, 2327.
(27) Mikata, Y.; Takeshita, N.; Miyazu, T.; Miyata, Y.; Tanase, T.;
Kinoshita, I.; Ichimura, A.; Mori, W.; Takamizawa, S.; Yano, S. J .
Chem. Soc., Dalton Trans. 1998, 1969.
(28) Allen, F. H.; Kennard, O.; Watson, D. G.; Brammer, L.; Orpen,
A. G.; Taylor, R. J . Chem. Soc., Perkin Trans. 1987, 2, S1.
(29) (a) Hachgenei, J . W.; Angelici, R. A. J . Organomet. Chem. 1988,
355, 359. (b) Reynolds, M. A.; Guzei, I. A.; Angelici, R. J . Organome-
tallics 2001, 20, 1071. (c) Vecchi, P. A.; Ellern, A.; Angelici, R. J . J .
Am. Chem. Soc. 2003, 125, 2064.
(21) (a) Ulrich, N.; Keller, H.; Stegmair, C.; Kreissl, F. R. J .
Organomet. Chem. 1989, 378, C19. (b) Yamazaki, S.; Ama, T.; Hojo,
M.; Ueno, T. Bull. Chem. Soc. J pn. 1989, 62, 4036. (c) Yamazaki, S.;
Deeming, A. J . Polyhedron 1996, 11, 1847.

Catalytic Hydrogenation of Thiophene
Organometallics, Vol. 22, No. 23, 2003 4807
Sch em e 2. Ca ta lytic Activity of 1 tow a r d
S-Heter oa r om a tic Com p ou n d s
thenacycle [Ru{SC(COMe)dCHCHdCH}(depe)2] is ob-
served with a Ru-S bond of 2.427(2) Å, longer than in
3 (2.281(2) Å).
It should be noted that reaction of 2-AcT with 1
coordinating two dihydrogen molecules is a very clean
reaction. The reaction is total, and 3 was isolated in very
good yield (93%). Synthesis of this product requires the
C5-S bond cleavage in 2-AcT, formal hydrogenation of
two CdC double bonds, and formation of a new CdC
double bond. No other products are observed when the
reaction is performed in an NMR tube and followed by
1H and 31P NMR spectroscopy.
Reaction of 1 with Diben zo[b,d]th ioph en e (DBT).
Ch a r a ct er iza t ion of [R u H 2(η2-H 2)(η1(S)-C12H 8S)-
(P Cy3)2] (4). Reaction of 1 with dibenzo[b,d]thiophene
(DBT) in pentane leads to the formation of a yellow-
green solid. NMR studies indicate the formation of a
new complex, 4, contaminated with some unreacted 1
and free DBT. 4 was characterized as a dihydride-
(dihydrogen)(DBT) species, [RuH2(η2-H2)(η1(S)-C12H8S)-
1
(PCy3)2] (see Scheme 1). The H NMR spectrum shows
a broad hydride resonance at δ -8.2 and four signals
in the low-field region between δ 8.3 and 7.4. At 253 K
the four signals of equal intensity are well-resolved. The
multiplicities and chemical shifts (see Experimental
Section) are very similar to those found for other
complexes in which the DBT ligand is η1(S)-bound to
the metal.4g,29b,c Such a formulation is also consistent
with the 2D-1H-1H{31P} COSY spectrum of 4. The ratio
between the hydride and the DBT signals indicates the
presence of four hydrogen atoms in the coordination
sphere of the metal. T1 measurements were performed
using the inverse-recovery method. A T1min of 36 ms (400
MHz, C7D8) is observed at 253 K. No decoalescence was
observed down to 193 K. These NMR data are in
agreement with a dihydride(dihydrogen) formulation.30
Bubbling dihydrogen into a C7D8 solution of 4 for 10
min at room temperature resulted in total substitution
of the bound DBT by H2, leading thus to the recovery
of the starting material 1. The reaction was monitored
by 1H and 31P NMR spectroscopies and showed no traces
of any product resulting from DBT hydrogenation.
Ca ta lytic Stu d ies. The catalytic experiments were
typically performed at 80 °C under 3 bar of H2 in
cyclohexane, using 1 as catalyst precursor with a
catalyst/S-substrate ratio of 1:50. The mixture was
maintained at 80 °C for 24 h. The composition of the
resulting mixture was determined by GC-MS analysis
and by NMR. The reactions are described in Scheme 2,
and the results are summarized in Table 2.
observed (by GC and 1H NMR), and 1 was the only
ruthenium species present in the reaction mixture, as
1
detected by H and 31P NMR at the end of the experi-
ment. It should be noted that, in this experiment,
concentrations of 1 and T were 5 times larger as
compared with those applied in the standard hydroge-
nation tests, thus allowing a total conversion of T into
THT. We have shown above that reaction of 1 with a
2-fold excess of T leads to a formal elimination of two
H2 molecules and isolation of the new complex 2
incorporating a thioallyl ligand. We have also mentioned
that 1 was regenerated by bubbling H2 into a C6D6
solution of 2 with concomitant formation of THT. It was
therefore straightforward to check the catalytic activity
of 2. Remarkably, when using 2 as catalyst precursor
(entry 3) in the same conditions used with 1 (entry 1),
a slightly higher conversion of T was obtained. This
suggests the involvement of 2, at least as a transient
form, in a catalytic cycle for T hydrogenation. To the
best of our knowledge, our findings represent the first
example of a homogeneous hydrogenation of T to THT.
The only previous report in connection to that work
refers to an iridium system in which the S-bound
thiophene complex [IrH(η1-SC4H4)2(PPh3)2][PF6] was
hydrogenated to the corresponding THT complex [IrH-
(η1-SC4H8)2(PPh3)2][PF6].4a This reaction formally cor-
responds to two catalytic cycles. Another example of a
stoichiometric hydrogenation of T to THT was also
reported by thermolysis of the η4-thioallyl complex
[ReH2(η4-SC4H5)(PPh3)2].19 Also relevant to our work is
the hydrogenolysis of T in drastic conditions (up to 60%
conversion at 160 °C under 30 atm of H2) catalyzed by
the rhodium complex [(triphos)Rh(η3-SCHdCHCHd
Hydrogenation of T with 1 as catalyst precursor
results in 85% conversion after 24 h and selective
formation of tetrahydrothiophene (THT) (entry 1 of
Table 2). Reduction of 2-methylthiophene (2-MeT) to
2-methyltetrahydrothiophene (2-MeTHT) proceeds at a
much slower rate, as only 11% of 2-MeT is converted in
the same conditions (entry 4). This might be attributed
to the steric hindrance imposed by the methyl group at
the C2 carbon. A catalytic hydrogenation test of T was
also performed in d12-cyclohexane in the presence of 1
(see entry 2). Total conversion of T into THT was
(30) Kubas, G. J . In Metal Dihydrogen and σ-Bond Complexes;
Fackler, J . P., Ed.; Kluwer Academic/Plenum Publishers: New York,
2001.

4808 Organometallics, Vol. 22, No. 23, 2003
Ta ble 2. Hyd r ogen a tion of S-Ar om a tic Com p ou n d sa
Borowski et al.
entry
substrate
conversion (%)
productsb
TONc
1
2
3
4
5
6
7
8
thiophene
85
100
87
11
ca. 60
80
THT
THT
THT
2-MeTHT
1-(2-Tyl)E
1-(2-Tyl)E
1-(2-Tyl)E
2-TM
42.5
50
43.5
5.5
ca. 30
40
ca. 30
45
thiophened
thiophenee
2-methylthiophene
2-acetylthiophene
2-acetylthiophenef
2-acetylthiopheneg
2-thiophene-
ca. 60
90
carboxaldehyde
benzo[b]thiophene
dibenzo[b,d]thiopheneh
9
10
86
0
DHBT
43
0
a
Unless stated otherwise, 1 is the catalyst precursor. Conditions: 80 °C, 3 bar H2, 24 h; solvent, cyclohexane (10 mL); [Ru] ) 3 × 10-3
b
M; [substrate] ) 0.15 M, substrate/Ru ) 50. The products were analyzed by GC/MS. Products: THT ) 2,3,4,5-tetrahydrothiophene;
2-MeTHT ) 2-methyltetrahydrothiophene; 1-(2-Tyl)E ) 1-(2-thienyl)ethanol; 2-TM ) 2-thiophenemethanol; DHBT ) 2,3-dihydroben-
zothiophene. 100% selectivity for each product. c TON is defined as mole of product formed per mole of Ru. Solvent: d12-cyclohexane (2
d
mL), [Ru] ) 15 × 10-3 M, [substrate] ) 0.75 M, thiophene/Ru ) 50, reaction time 17 h. The products were analyzed by GC and 1H NMR.
e [RuH(η4-SC4H5)(PCy3)2] (2) was used as a catalyst precursor; concentrations and conditions as in footnote a. f Solvent: d12-cyclohexane
(2 mL), [Ru] ) 15 × 10-3 M, [substrate] ) 0.75 M, 2-AcT/Ru ) 50, reaction time 18 h. The products were analyzed by 1H NMR and
GC/MS. g [RuH2{η2(O,S)-C6H10OS}(PCy3)2] (3) was used as a catalyst precursor; concentrations and conditions as in footnote a. Conditions
h
as in footnote a but with a dihydrogen pressure of 20 bar.
CH2)] in the presence of a strong base KOtBu. A mixture
of 1-butanethiol, n-butane, and butenes was obtained.7b
Interestingly, a complete desulfurization of T to n-
butane was reported from the dimer [(Cp*IrHCl)2] via
a butanethiolate intermediate.14c
coordination sphere of the metal, and effective desulfu-
rization of the activated DBT molecule under relatively
mild conditions,3,13-15 there are no examples of homo-
geneous hydrogenation of arene rings in DBT in the
presence of soluble metal complexes. Likewise, our
system does not show any activity in hydrogenation of
DBT (at 80 °C, under 3 or 20 bar H2), correspondingly
to our previous findings for tetralin and 9,10-dihydro-
antracene.18c Nevertheless, we noted a color change from
beige to yellow of the reaction mixture containing 1 and
DBT under a dihydrogen atmosphere, thus suggesting
the formation of a new product. Indeed, we have shown
above that stoichiometric reaction of 1 and DBT affords
the new dihydrogen yellow complex [RuH2(η2-H2)(η1(S)-
C12H8S)(PCy3)2] (4) in which the DBT ligand is coordi-
nated to the metal via the sulfur atom. Such a coordi-
nation mode might be responsible for the fact that we
could not observe any DBT hydrogenation.
Hydrogenation of 2-AcT in the presence of 1 leads to
the selective hydrogenation of the carbonyl group and
formation of the secondary alcohol 1-(2-thienyl)ethanol
(1-(2-Tyl)E), leaving the heteroaromatic ring intact as
1
analyzed by GC/MS and H NMR. A 60% conversion of
2-AcT was obtained after 24 h of reaction at 80 °C under
3 bar of H2 (entry 5). The formation of this alcohol was
also confirmed by running an experiment in d12-cyclo-
hexane for in situ NMR measurements (entry 6 and see
Experimental Section). As we have found in the previous
case for catalytic thiophene hydrogenation by 1 or 2,
the isolated complex 3 resulting from the stoichiometric
reaction of 2-AcT with 1 can also be used as catalyst
precursor giving similar results (entry 7 versus 5).
Similarly, reduction of the aldehyde group in 2-thiophen-
ecarboxaldehyde (2-TA) leads to the formation of the
corresponding primary alcohol 2-thiophenemethanol (2-
TM) with 90% conversion as analyzed by GC/MS (entry
8).
As reported by other authors, drastic reaction condi-
tions (170 °C, 110 bar H2) are generally required to
achieve hydrogenation of benzo[b]thiophene (BT) to 2,3-
dihydrobenzo[b]thiophene (DHBT) with acceptable ini-
tial rates of ca. 6 TON/h.3 When the reaction temper-
ature is lowered to 85 °C and pressure reduced to 21
bar H2, the initial hydrogenation rates are below 1 TON/
h.17b,31 In our system BT is selectively reduced to DHBT
with an overal rate of 1.8 TON/h (86% conversion after
24 h) under our mild standard conditions (entry 9).
Thus, BT hydrogenation into DHBT occurs at the same
rate as T hydrogenation into THT. The isolated aromatic
ring of DHBT is reluctant to undergo hydrogenation.
We have observed similar results when testing tetralin
or indoline hydrogenation in the presence of 1 under
similar reaction conditions.18c,d
Su m m a r y
We have shown that the bis(dihydrogen) ruthenium
complex 1 can activate several S-heteroaromatic com-
pounds both stoichiometrically and catalytically. Activa-
tion is obviously dependent on the nature of the
S-substrate, leading to new organometallic compounds
presenting different coordination modes of the S-sub-
strates. In the case of thiophene, we were able to isolate
the product resulting from its coordination as a thioallyl-
(hydride) complex 2 and to prove that both 1 and 2 serve
as catalyst precursors for thiophene hydrogenation. The
coordination of thiophene as a thioallyl ligand in 2 is
probably responsible for the good performance of our
catalysts. Indeed, this coordination mode lowers the
aromatic resonance stabilization energy, allowing an
easy thiophene hydrogenation into tetrahydrothiophene
in mild conditions, whereas no hydrogenation of DBT
was observed. It was known from the literature that the
presence of thiophene substituents on the 2 or 3 posi-
tions favored the C-S bond cleavage. It was indeed
what we observed by using 2-AcT, but in our case, the
C-S bond cleavage resulted in the unexpected forma-
tion of 3, a dihydride metallacycle with an O,S-bound
ligand. When testing 2-AcT hydrogenation, we did not
observe any hydrogenation of the aromatic ring, but
Although there are several examples of C-S bond
scission with DBT followed by C-S insertion into the
(31) (a) Fish, R. H.; Tan, J . L.; Thormodsen, A. D. J . Org. Chem.
1984, 49, 4500. (b) Fish, R. H.; Baralt, E.; Smith, S. J . Organometallics
1991, 10, 54.

Catalytic Hydrogenation of Thiophene
Organometallics, Vol. 22, No. 23, 2003 4809
(0.042 g, 0.225 mmol) in pentane (4 mL) at room temperature.
A yellow-green solid precipitated that was filtered off, washed
with pentane (3 × 1.5 mL), and dried in vacuo. The solid was
contaminated by some unreacted 1 and DBT. Any attempt to
purify it by recrystallization failed, leading to decomposition.
reduction of the keto function into 1-(2-thienyl)ethanol
was catalyzed by 1 and 3 under dihydrogen pressure.
A similar reaction was observed for the reduction of
2-thiophenecarboxaldehyde into 2-thiophenemethanol.
1
It was thus impossible to obtain any micronalytical data. H
NMR (400 MHz, C7D8, 253 K): δ 8.22 (d, 2H, H1,9, J H-H ) 8.0
Hz), 7.82 (d, 2H, H4,6, J H-H ) 7.9 Hz), 7.41 (vt, 2H, H2,8, J H-H
) 7.1 Hz), 7.25 (vt, 2H, H3,7, J H-H ) 7.5 Hz), 2.2-1.0 (m, 66H,
PCy3), -8.2 (br s, 4H, Ru-H). 31P{1H} NMR (162 MHz): δ
70.0 (s).
Exp er im en ta l Section
Gen er a l P r oced u r es. All manipulations were carried out
under argon using standard Schlenk-line techniques. All
solvents were freshly distilled from standard drying agents
and thoroughly degassed under argon prior to use. RuCl3‚3H2O
was purchased from J ohnson Mattey Ltd., and all other
reagents were purchased from Aldrich or Fluka and were used
as obtained (except DBT, which was purified by sublimation)
but degassed before use. Reaction products were analyzed by
GC on a Hewlett-Packard 5890 apparatus fitted with a FID
detector using a capillary column (30 mm × 0.32 mm) packed
with cross-linked methyl silicone. GC/MS (EI, 70 eV) deter-
minations were performed on an HP 5970 MSD apparatus
fitted with the column of analogous characteristics. Homoge-
neity of the reaction mixtures has been confirmed by the test
with liquid mercury, which is known to inhibit colloidal
catalysis.32 1 was prepared by the published method,33 and
hydrogenations were performed as previously reported.18c
Microanalysis were performed by the Laboratoire de Chimie
de Coordination Microanalytical Service. Proton and phospho-
rus spectra were recorded on a Bruker AC 200 (at 200.132 and
81.015 MHz, respectively) and on an AMX 400 (at 400.130 and
161.985 MHz) apparatus. The 13C NMR spectra were obtained
by using a Bruker AMX 400 (100.624 MHz) spectrometer.
[Ru H(η4(S,C)-SC4H5)(P Cy3)2] (2). After adding thiophene
(0.024 mL, 0.3 mmol) to a suspension of 1 (0.100 g, 0.15 mmol)
in pentane (2 mL), the color of the solution changed from beige
to yellow-green. The suspension was stirred for 1 h, during
which time a beige precipitate formed that was filtered off,
washed with cold pentane (2 × 1 mL), and dried in vacuo.
Yield: 0.096 g (77%). Anal. Calcd for C40H72P2SRu: C, 64.26;
1-(2-Th ien yl)eth a n ol. 1H NMR (200 MHz, d12-cyclohexane,
293 K): δ 7.31 (m, 1H, H5), 7.08 (m, 2H, H3,4), 5.20 (q, 1H,
J H-H ) 6,5 Hz, CH), 4.76 (br s, 1H, OH), 1.70 (d, 3H, J H-H
)
6.5 Hz, CH3). Comparisons can be made with data from ref
34.
X-r a y Da ta . Data were collected at low-temperature (T )
180 K) on a Stoe imaging plate diffraction system (IPDS)
equipped with an Oxford Cryosystems cooler device. The
crystal-to-detector distance was 70 mm, and 133 exposures
were obtained with the crystal oscillating 1.5° in æ. The final
unit cell parameters were obtained by least-squares refinement
of 5000 reflections. No significant fluctuation of the intensity
was observed. The structure was solved by direct methods
using the program SIR9235 and refined by least-squares
procedures on F2 using SHELXL-97.36 All hydrogen atoms were
located on a difference Fourier map, but they were introduced
in calculations in idealized positions with an isotropic thermal
parameter fixed at 20% higher than those of the carbon atoms
to which they were connected. The hydrides were isotropically
refined. All non hydrogen atoms were anisotropically refined.
Least-squares refinements were carried out by minimizing the
function ∑w(|Fo| - |Fc|)2, where Fo and Fc are the observed and
calculated structure factors. A weighting scheme was used in
the last refinement cycles, where weights are calculated from
the following expression: w ) [weight] × [1 - (∆(F)/6σ(F)]2.
The model reached convergence with Rw ) [∑w(||Fo| - ||Fc|)2/
∑(|Fo|)2]1/2. The criteria for a satisfactory complete analysis
were the ratios of rms shift to standard deviation being less
than 0.1 and no significant features in final difference maps.
All calculations were performed by using WinGX program
version 1.64-04.37 The molecules were drawn with the aid of
ORTEP32,38 and the atomic scattering factors were taken from
International Tables for X-Ray Crystallography.39
1
H, 9.65. Found: C, 64.46; H, 9.52. H NMR (200 MHz, C6D6,
293 K): δ 5.56 (brs, 1H, H5), 5.31 (brs, 1H, H4), 4.27 (pst, 1H,
2(exo)
2(endo)
H2(exo), J P-H ) 9.0 Hz), 3.73 (d, 1H, H2(endo), J H
)
-H
9.0 Hz), 2.71 (brs, 1H, H3), 2.5-1.1 (m, 66H, PCy3), -20.90
(dd, 1H, J P-H ) 28 and 35 Hz, Ru-H). 31P{1H} NMR (81
MHz): δ 61.7 (br) and δ 53.0 (br).
[Ru H2{η2(O,S)-C6H10OS}(P Cy3)2] (3). An addition of 1
equiv of 2-acetylthiophene (0.164 mL, 0.15 mmol) to a suspen-
sion of 1 (0.100 g, 0.15 mmol) in pentane (14 mL) resulted in
an immediate color change of the solution from the initial beige
to violet and finally after ca. 5 min to deep red. This suspension
was stirred overnight, and after filtration, the resulting red
solution was evaporated to dryness, leading to the obtention
of a dark red voluminous solid. Yield: ca. 0.11 g (93%). Anal.
Calcd for C42H78OP2SRu: C, 63.50; H, 9.90. Found: C, 63.35;
H, 10.07. 1H NMR (400 MHz, C6D6, 293 K): δ 3.16 (t, 2H, J H-H
Ack n ow led gm en t. This work was supported by the
Polish Academy of Sciences and the CNRS under
Contract No. 9774 and the Committee for Scientific
Research (KBN) under Contract No. PBZ-KBN 15/T09/
99/01d (A.F.B.).
4
1
Su p p or tin g In for m a tion Ava ila ble: X-ray structural
data for 3 (CIF). NMR spectra of 4 before and after treatment
with dihydrogen. This material is available free of charge via
the Internet at http://pubs.acs.org.
) 7.2 Hz, CH2), 2.65 (s, 3H, CH3), 2.10 (dt, 2H, J H-H ) 7.2
Hz, 5CH2), 1.16 (t, 3H, J H-H ) 7.2 Hz, 6CH3), 2.3-1.1 (m, 66H,
PCy3), -10.37 (t, 2H, J P-H ) 33.3 Hz, Ru-H2). 31P{1H} NMR
(162 MHz): δ 82.9 (s). 13C{1H} NMR (100 MHz): δ 167.3 (s,
C2O), 121.4 (s, C3S), 37.7 (s, C4H2), 26.1 (s, C5H2), 21.7 (s, C1H3),
13.9 (s, C6H3).
OM0304309
Crystals suitable for X-ray diffraction analysis were grown
by dissolving the red solid in a small amount of acetone. The
resulting solution was kept at room temperature for a few
days.
[Ru H2(η2-H2)(η1(S)-C12H8S)(P Cy3)2] (4). Complex 1 (0.100
g, 0.15 mmol) was stirred overnight with dibenzo[b,d]thiophene
(34) Fuller, L. S.; Iddon, B.; Smith, K. A. J . Chem. Soc., Perkin
Trans. 1 1997, 3465.
(35) Altomare, A.; Cascarano, G.; Giacovazzo G.; Guagliardi A.;
Burla M. C.; Polidori, G.; Camalli, M. J . Appl. Crystallogr. 1994, 27,
435.
(36) Sheldrick, G. M. SHELX-97, Program for Crystal Structure
Analysis; Go¨ttingen: Germany, 1998.
(37) WINGX Program. Farrugia, L. J . J . Appl. Crystallogr. 1999,
32, 837.
(38) ORTEP32 for Windows. Farrugia, L. J . J . Appl. Crystallogr.
1997, 30, 565.
(39) International Tables for X-Ray Crystallography; Kynoch
Press: Birmingham, England, 1974; Vol IV.
(32) (a) Anton, D. R.; Crabtree, R. H. Organometallics 1983, 2, 855.
(b) Morton, D.; Cole-Hamilton, D. J .; Utuk, I. D.; Paneque-Sosa, M.;
Lo´pez-Poveda, M. J . Chem. Soc., Dalton Trans. 1989, 489.
(33) Borowski, A. F.; Sabo-Etienne, S.; Christ, M. L.; Donnadieu,
B.; Chaudret, B. Organometallics 1996, 15, 1427.