Carbon-hydrogen bond cleavage reaction in 5-coordinate bis(2,6- dimethylbenzenethiolato)ruthenium(II) complexes

Article abstract of DOI:10.1021/om100249s

A series of bis(2,6-dimethylbenzenethiolato)ruthenium(II) complexes, Ru(SC₆H₃Me₂-2,6-k:¹S) ₂-(TRIPHOS-k₃P,P',P ) (2a), Ru(SC₆H ₃Me₂-2,6-k¹S)₂(TDPME-k ³P,P',P') (2b), trans-Ru(SC₆H₃-Me ₂-2,6-k¹S)₂(DPPE-k²P,P')2 (3c) and Ru(SC₆H₃Me2-2,6-k¹S)₂(PMe ₃)₃ (2d) are prepared. Treatment of 2a with PMe ₃ in benzene at 50 °C results in the sp³ C-H bond cleavage reaction of the ortho methyl in thiolato group to give a stereochemical mixture of thiaruthenacycle complex Ru[SC₆H₃-(CH ₂-2)(Me-6)-k²S,C](TRIPHOS-k³P,P',P ) (PMe₃) (1a) in 70% yield ([(OC-6-34)-1a]/[(OC-6-25)-1a] = 80/20) with concomitant liberation of 2,6-dimethylbenzenethiol. Similar treatment of 2d with PMe₃ in benzene at room temperature rapidly produced cis-Ru[SC₆H₃(CH₂-2)(Me-6)-k²S, C](PMe₃)₄ (1d) quantitatively. Treatment of 2b with PMe₃ results in the formation of 1d by the C-H bond cleavage reaction and ligand displacement reaction. The C-H bond cleavage reaction does not occur from 3c under these conditions. Treatment of 2d with PMe₃ in methanol does not give 1d at all but yields cis-Ru(SC₆H ₃Me₂-2,6-k¹S)₂(PMe₃) ₄ (3d), which is not responsible for formation of 1d, suggesting importance of coordinative unsaturation for the C-H bond cleavage reaction. The kinetic study suggests that present C-H bond cleavage reaction proceeds by a concerted mechanism.

Full text of DOI:10.1021/om100249s

3146 Organometallics 2010, 29, 3146–3159
DOI: 10.1021/om100249s
Carbon-Hydrogen Bond Cleavage Reaction in 5-Coordinate
Bis(2,6-dimethylbenzenethiolato)ruthenium(II) Complexes
Masafumi Hirano,* Sayaka Togashi, Muneaki Ito, Yuko Sakaguchi, Nobuyuki Komine,
and Sanshiro Komiya*
Department of Applied Chemistry, Graduate School of Engineering, Tokyo University of Agriculture and
Technology, 2-24-16 Nakacho, Koganei, Tokyo 184-8588, Japan
Received March 30, 2010
A series of bis(2,6-dimethylbenzenethiolato)ruthenium(II) complexes, Ru(SC6H3Me2-2,6-κ1S)2-
(TRIPHOS-κ3P,P0,P00) (2a), Ru(SC6H3Me2-2,6-κ1S)2(TDPME-κ3P,P0,P00) (2b), trans-Ru(SC6H3-
Me2-2,6-κ1S)2(DPPE-κ2P,P0)2 (3c) and Ru(SC6H3Me2-2,6-κ1S)2(PMe3)3 (2d) are prepared. Treat-
ment of 2a with PMe3 in benzene at 50 °C results in the sp3 C-H bond cleavage reaction of the ortho
methyl in thiolato group to give a stereochemical mixture of thiaruthenacycle complex Ru[SC6H3-
(CH2-2)(Me-6)-κ2S,C](TRIPHOS-κ3P,P0,P00)(PMe3) (1a) in 70% yield ([(OC-6-34)-1a]/[(OC-6-
25)-1a]=80/20) with concomitant liberation of 2,6-dimethylbenzenethiol. Similar treatment of 2d
with PMe3 in benzene at room temperature rapidly produced cis-Ru[SC6H3(CH2-2)(Me-6)-κ2S,
C](PMe3)4 (1d) quantitatively. Treatment of 2b with PMe3 results in the formation of 1d by the C-H
bond cleavage reaction and ligand displacement reaction. The C-H bond cleavage reaction does not
occur from 3c under these conditions. Treatment of 2d with PMe3 in methanol does not give 1d at all
but yields cis-Ru(SC6H3Me2-2,6-κ1S)2(PMe3)4 (3d), which is not responsible for formation of 1d,
suggesting importance of coordinative unsaturation for the C-H bond cleavage reaction. The kinetic
study suggests that present C-H bond cleavage reaction proceeds by a concerted mechanism.
Introduction
cleavage reactions of phosphates,4 isonitrile,5 carbonyls,6
alcohols,7 phenols,8 carboxylic acids,9 amines,10 and pyr-
idines11 are documented and these reactions are considered
to involve prior coordination (or covalent bond formation) step
before the C-H bond cleavage reactions. In addition, the
C-H bond cleavage reactions by cleaving the covalent metal-
chalcogen bond such as σ bond metathesis and electrophilic
substitution currently attract a great deal of interest as new
potential pathways for molecular transformation.12-17,44
We are interested in the bond cleavage reactions of ortho
substituents in (aryloxo)- and (arenethiolato)ruthenium(II)18
complexes, where the chalcogen anchor effectively brings
the ortho substituent in proximity to the ruthenium center.
Since Chatt and Davidson reported the first C-H bond
cleavage reaction by a zerovalent ruthenium complex,1
activation of C-H bond by low valent ruthenium complexes
has been of long-standing interest because of the potential
applications of the process for direct functionalization of
inactive organic compounds.2 One of the key factors in such
bond activation processes is how to bring a C-H bond in
proximity to the ruthenium center.3 In fact, the C-H bond
*To whom correspondence should be addressed. Phone and fax: þ81
423 887 044. E-mail: hrc@cc.tuat.ac.jp (M.H.); komiya@cc.tuat.ac.jp
(S.K.) .
(1) Chatt, J.; Davidson, J. M. J. Chem. Soc. 1965, 843.
(2) (a) Murai, S., Ed., Activation of Unreactive Bonds and Organic
Synthesis, Springer: Berlin, 1999. (b) Arndtsen, B. A.; Bergman, R. G.;
Moley, T. A.; Peterson, T. H. Acc. Chem. Res. 1995, 28, 154. (c) Crabtree,
R. H. Chem. Rev. 1985, 85, 254. (d) Shilov, A. E.; Shteinman, A. A. Coord.
Chem. Rev. 1977, 24, 97. (d) Shilov, A. E. The Activation of Saturated
Hydrocarbons by Transition Metal Complexes; Reidel: Dordrecht, The
Netherlands, 1984. (e) Wasserman, E. P.; Moore, C. B.; Bergman, R. G.
Science 1992, 255, 315. (f) Homogeneous Transition Metal Catalyzed
Reactions; Moser, W. R., Slocum, D. W., Eds.; Advances in Chemistry 230;
American Chemical Society: Washington, DC; 1992. (g) Naota, T.; Takaya,
H.; Murahashi, S. Chem. Rev. 1998, 98, 2599. (h) Kakiuchi, F.; Murai, S.
Acc. Chem. Res. 2002, 35, 826. (i) Fundamentals of Molecular Catalysis;
Kurosawa, H.; Yamamoto, A., Eds.; Elsevier: Amsterdam, 2003. (j) Mur-
ahashi, S., Ed. Ruthenium in Organic Synthesis; Wiley: New York; 2004.
(k) Komiya, S.; Hirano, M. Dalton Trans. 2003, 1439.
(6) (a) Komiya, S.; Ito, T.; Cowie, M.; Yamamoto, A.; Ibers, J. A.
J. Am. Chem. Soc. 1976, 98, 3874. (b) Murai, S.; Kakiuchi, F.; Sekine, S.;
Tanaka, Y.; Kamatani, A.; Sonoda, M.; Chatani, N. Nature 1993, 366, 529.
(7) (a) Ozawa, F.; Yamagami, I.; Yamamoto, A. J. Organomet.
Chem. 1994, 473, 265. (b) Kanaya, S.; Imai, Y.; Komine, N.; Hirano, M.;
Komiya, S. Organometallics 2005, 24, 1059.
(8) (a) Hartwig, J. F.; Bergman, R. G.; Andersen, R. A. J. Am. Chem.
Soc. 1991, 113, 3404. (b) Hartwig, J. F.; Bergman, R. G.; Andersen, R. A.
J. Am. Chem. Soc. 1991, 113, 6499. (c) Hirano, M.; Sato, H.; Kurata, N.;
Komine, N.; Komiiya, S. Organometallics 2007, 26, 2005.
(9) Kanaya, S.; Komine, N.; Hirano, M.; Komiya, S. Chem. Lett.
2001, 1284.
(10) (a) Yi, C. S.; Yun, S. Y. J. Am. Chem. Soc. 2005, 127, 17000.
(b) Pastine, S. J.; Gribkov, D. V.; Sames, D. J. Am. Chem. Soc. 2006, 128,
14220.
(3) Djukic, J.-P.; Sortais, J.-B.; Barloy, L.; Pfeffer, M. Eur. J. Inorg.
Chem. 2009, 817.
(4) Lewis, L. N.; Smith, J. F. J. Am. Chem. Soc. 1986, 108, 2728.
(5) Hsu, G. C.; Kosar, W. P.; Jones, W. D. Organometallics 1994, 13,
385.
(11) Moore, E. J.; Pretzer, W. R.; O’Connell, T. J.; Harris, J.;
LaBounty, L.; Chou, L.; Grimer, S. J. Am. Chem. Soc. 1992, 114, 5888.
(12) Thompson, M. E.; Baxter, S. M.; Bulls, A. R.; Burger, B. J.;
€
Nolan, M. C.; Santarsiero, B. D.; Schofer, W. P.; Bercaw, J. E. J. Am.
Chem. Soc. 1987, 109, 203.
r
pubs.acs.org/Organometallics
Published on Web 06/24/2010
2010 American Chemical Society

Article
Organometallics, Vol. 29, No. 14, 2010 3147
Scheme 1
Of particular interest is the sp3 C-H bond cleavage reaction
of the ortho methyl groups in cis-RuH(SC6H3Me2-2,6-κ1S)-
(PMe3)4, where the C-H bond in the ortho methyl group is
cleaved only by removing evolved hydrogen gas by evacuation
of the reaction system to form a thiaruthenacycle complex
Ru[SC6H3(CH2-2)(Me-6)-κ2S,C](PMe3)4 (1d) at room tem-
perature.18 This finding prompted us to study the synthesis
and reactions of a series of (2,6-dimethylbenzenethiolato)-
ruthenium(II) complexes. In this article, we describe the
preparation of a series of bis(2,6-dimethylbenzenethiolato)-
ruthenium(II) complexes with tri-, bi-, and monodentate ter-
tiary phosphine ligands, and the mechanism for the sp3 C-H
bond cleavage process giving thiaruthenacycle complexes.
Results and Discussion
1. Preparation of Bis(2,6-dimethylbenzenethiolato)ruthenium-
(II) Complexes. A series of bis(2,6-dimethylbenzenethiolato)-
ruthenium(II) complexes containing tri-, bi-, and monodentate
phosphine ligands were prepared by direct reaction of a zero-
valent complex with thiol or metathetical reaction of the cor-
responding dichlorido complex with thiolate anion. The feasible
synthetic pathways were summarized in Scheme 1.
1.1. Tridentate Phosphine Complexes. A TRIPHOS [(Ph2-
PC2H4)2PPh] complex was prepared by the following man-
ner. Reaction of Ru(η4-1,5-COD)(η6-1,3,5-COT) (5) with
TRIPHOS in benzene at 70 °C for 48 h yielded Ru(η4-1,5-
COD)(TRIPHOS-κ3P,P0,P00) (4a) as analytically pure yel-
low plates from cold toluene/hexane in 89% yield. The over-
all molecular structure of 4a displays a distorted trigonal
bipyramidal complex with an η4-1,5-COD and a κ3P,P0,P00-
TRIPHOS ligand on Ru(0) center, where the P(2) and the
center between C(5) and C(6) locate on the axial positions
[the angle P(2)-Ru(1)-the center between C(5) and C(6) is
(13) (a) Gunnoe, T. B. Eur. J. Inorg. Chem. 2007, 1185. (b) DeYonker,
N. J.; Foley, N. A.; Cundari, T. R.; Gunnoe, T. B.; Petersen, J. L. Organo-
metallics 2007, 26, 6604. (c) Feng, Y.; Lail, M.; Foley, N. A.; Gunnoe, T. B.;
Barakat, K. A.; Cundari, T. R.; Petersen, J. L. J. Am. Chem. Soc. 2006, 128,
7982. (d) Feng, Y.; Gunnoe, T. B.; Grimes, T. V.; Cundari, T. R. Organo-
metallics 2006, 25, 5456. (e) Feng, Y.; Lail, M.; Barakat, K. A.; Cundari,
T. R.; Gunnoe, T. B.; Petersen, J. L. J. Am. Chem. Soc. 2005, 127, 14174.
(14) Davies, D. L.; Donald, S. M. A.; Al-Duaij, O.; Macgregor, S. A.;
€
Polleth, M. J. Am. Chem. Soc. 2006, 128, 4210.
(15) Snelgrove, J. L.; Conrad, J. C.; Yap, G. P. A.; Fogg, D. E. Inorg.
Chim. Acta 2003, 345, 268.
(16) (a) Oxgaard, J.; Tenn, W. J., III; Nielsen, R. J.; Periana, R. A.;
Goddard, W. A., III Organometallics 2007, 26, 1565. (b) Tenn, W. J., III;
Young, K. J. H.; Oxgaard, J.; Nielsen, R. J.; Goddard, W. A., III; Periana,
R. A. Organometallics 2006, 25, 5173. (b) Tenn, W. J., III; Young, K. J. H.;
Bhalla, G.; Oxgaard, J.; Goddard, W. A., III; Periana, R. A. J. Am. Chem.
Soc. 2005, 127, 14172. (c) Oxgaard, J.; Muller, R. P.; Goddard, W. A., III;
Periana, R. A. J. Am. Chem. Soc. 2004, 126, 352.
(17) Koike, T.; Ikariya, T. Organometallics 2005, 24, 724.
(18) Hirano, M.; Sakaguchi, Y.; Yajima, T.; Kurata, N.; Komine, N.;
Komiya, S. Organometallics 2005, 24, 4799.

3148 Organometallics, Vol. 29, No. 14, 2010
Hirano et al.
range. These variable temperature NMR data suggest appar-
ent exchange between two thiolato groups, probably by a
pseudorotation mechanism.
The reaction of 5 with TDPME [MeC(CH2PPh2)3] was
sluggish and gave a very complex mixture. When Ru(η6-
naphthalene)(η4-1,5-COD) (6) was employed as a starting
compound in benzene at 70 °C for 1 day, Ru(η4-1,3-COD)-
(TDPME-κ3P,P0,P00) (4b) was obtained in 53% yield after
recrystallization from cold acetone. The 31P{1H} NMR spec-
trum of 4b in benzene-d6 shows a singlet at δ 31.2 that indic-
ates all phosphorus atoms being equivalent. In the 1H NMR
spectrum in benzene-d6, the COD fragment is observed at δ
1.76 (br, 2H), 1.89 (br, 2H), 2.47 (br, 2H), 2.59 (br, 2H), 3.14
(m, 2H), and 5.25 (d, 2H). The spin correlations observed by
the 1H-1H COSY spectrum suggest isomerization of the 1,5-
COD fragment to η4-1,3-COD.20 Treatment of 4b with 5
equiv of 2,6-dimethylbenzenethiol in benzene at 70 °C for 1
day led to the formation of a 5-coordinate complex Ru(SC6-
H3Me2-2,6-κ1S)2(TDPME-κ3P,P0,P00) (2b) in 59% yield. The
31P{1H} NMR spectrum of 2b in benzene-d6 at room tem-
perature shows a sharp singlet at δ 40.5, suggesting that all
Figure 1. Molecular structure of Ru(η4-1,5-COD)(TRIPHOS-
κ3P,P0,P00) (4a) with numbering schemes. All hydrogen atoms
and incorporated toluene molecule were omitted for clarity.
Ellipsoids represent 50% probability.
1
phosphorus atoms are equivalent. The H NMR spectrum
shows sharp resonances at δ 1.06 (s, 3H) and 2.18 (s, 6H) for
the methyl and methylene protons in the TDPME ligand and
a singlet at δ 2.46 (s, 12H) assigned as the methyl resonances
of two thiolato groups. This feature indicates the two
thiolato groups to be equivalent at room temperature,
suggesting rapid apparent exchange between two thiolato
groups.
179.6(15)°], and P(1), P(3), and the center between C(1) and
C(2) constitute a trigonal plane (mean square deviation:
0.1236 A) (Figure 1).
˚
The 31P{1H} NMR spectrum of 4a at room temperature in
benzene-d6 shows a sharp AX2 pattern at δ 102.8 (t, 1P) and
δ 75.8 (d, 2P), suggesting two of three phosphorus atoms
being equivalent. In the 1H NMR spectrum of 4a in toluene-
d8, the methylene protons in the COD ligand appear as a
slightly broad signal at δ 2.2 (8H) and the methine protons
are almost merged into the baseline around δ 2.7-4.0 (4H) at
20 °C. At 100 °C, the methine signal appears at δ 3.2 as a
broad peak, which separates into two broad signals at δ 4.3
(2H) and δ 2.6 (2H) at -70 °C. During the variable temper-
ature 1H NMR experiment, no significant change was obser-
ved for the other resonances and the 31P{1H} NMR signals
remained sharp as an AX2 pattern over the entire tempera-
ture range (-70 to 100 °C). This fluxionality shows “apparent
rotation” of the η4-1,5-COD ligand on the 5-coordinate Ru
center either by Berry’s pseudo rotation or turnstile rotation
mechanism.19
1.2. Bidentate Phosphine Complexes. When RuCl2-
(DPPE-κ2P,P0)2 (7c) was treated with 3 equiv of potassium
2,6-dimethylbenzenethiolate in refluxing 1,4-dioxane for
28 h, a 6-coordinate complex trans-Ru(SC6H3Me-2,6-κ1S)2-
(DPPE-κ2P,P0)2 (3c) was obtained as yellow powder in 19%
yield.21 The 31P{1H} NMR of 3c in CD2Cl2 shows a sharp
singlet at δ 44.99, suggesting the trans configuration of the
dithiolato ligands. 1H NMR spectrum of 3c in CD2Cl2 shows
a broad signal at δ 2.74 (br, 8H), a sharp singlet at δ 3.65 (s,
12H) ,and multiplet in the range δ 7.02-7.25 (m, 46H). These
resonances are assignable to the methylene protons in DPPE,
the ortho methyl protons in the thiolato group, and the
aromatic protons in DPPE and in the thiolato groups,
respectively. It is notable that the ortho methyl groups (δ
3.65) resonate at lower magnetic field than 2a (δ 2.11), 2b (δ
2.46), 2d (δ 2.55), and free 2,6-dimethylbenzenethiol (δ 2.48).
This downfield shift may be explained by deshielding effect
caused by the equatorial phenyl groups in 3c.
Treatment of 4a with 5 equiv of 2,6-dimethylbenzenethiol
in acetonitrile at 70 °C for 6 h gave a 5-coordinate bis(2,6-
dimethylbenzenethiolato)ruthenium(II) complex, Ru(SC6H3-
Me2-2,6-κ1S)2(TRIPHOS-κ3P,P0,P00) (2a) in 88% yield as
analytically pure dark-purple crystals, whose molecular
structure was revealed by the X-ray analysis (vide infra). In
the 31P{1H} NMR spectrum of 2a, the TRIPHOS ligand is
observed as an AX2 pattern at δ 88.7 (t, 1P) and 81.5 (d, 2P)
1.3. Monodentate Phosphine Complexes. An analytically
pure 5-coordinate trimethylphosphine complex of bis(2,6-
dimethylbenzenethiolato)ruthenium(II) Ru(SC6H3Me2-2,6-
κ1S)2(PMe3)3 (2d) was prepared and isolated by the metathe-
tical reaction of trans-RuCl2(PMe3)4 (7d) with potassium
2,6-dimethylbenzenethiolate in DME at 50 °C for 3 days.
The product yield of 2d was poor (17%) due to concomitant
1
in CD2Cl2. In the H NMR spectrum of 2a in CD2Cl2 at
room temperature, two broad peaks are observed at δ 2.1
(12H) and 6.4 (6H) assignable to the ortho methyl groups and
aromatic protons in the 2,6-dimethylbenzenethiolato frag-
ments. On cooling the solution, the ortho methyl and aro-
matic resonances gradually collapsed and then at -20 °C
new signals appeared at δ 2.0 (s, 6H), 2.2 (s, 6H), 6.2 (d, 2H),
and 6.3 (t, 1H). Remaining one set of aromatic protons (3H)
in the thiolato group may be obscured by overlapping with
the TRIPHOS signals at δ 6.6. The 31P{1H} NMR resonances
are remained sharp as an AX2 pattern in this temperature
(20) The isomerization to 1,3-COD from 1,5-COD proceeded in this
reaction. Although detailed mechanism for this isomerization was not
clear to date, it occurred during the purification process in acetone
because the reaction of 5 with TDPME in C6D6 monitored by the NMR
suggests dominant formation of Ru(η4-1,5-COD)(TDPME) (4b0). One
of the reasonable explanations is that a protic species catalyzes the
isomerization from 1,5-COD to the more stable 1,3-COD Hirano, M.;
Shibasaki, T.; Komiya, S.; Bennett, M. A. Organometallics 2002, 21,
5738.
(19) Yamamoto, A. in Organotransition Metal Chemistry, Funda-
mental Concepts and Applications; Wiley: New York, 1986, pp 190.
(21) Similar trans- and cis-Ru(SPh)2(DMPE-κ2P,P0)2 were reported
Field, L. D.; Hmbley, T. W.; Ya, B. C. K. Inorg. Chem. 1994, 33, 2009.

Article
Organometallics, Vol. 29, No. 14, 2010 3149
formation of a thiaruthenacycle complex cis-Ru[SC6H3-
(2-CH2)(6-Me)-κ2S,C](PMe3)4 (1d)18 (69%) and cis-Ru-
(SC6H3Me2-2,6-κ1S)2(PMe3)3(OH2) (3e) (9%) whose forma-
tion processes are discussed later. Complex 2d was
characterized by NMR, elemental analysis and the chemical
reactions, and the unambiguous molecular structure was
finally determined by the X-ray analysis (vide infra). One
PMe3 has been lost during the formation of 2d from 7d. Pro-
bably, the initial tetrakis-phosphine product Ru(SC6H3Me2-
2,6-κ1S)Cl(PMe3)4, or more likely Ru(SC6H3Me2-2,6-κ1S)2-
(PMe3)4, would favor liberation of one PMe3 under these
conditions because of donation of lone pair electrons in the
thiolato group.
The 31P{1H} NMR spectrum of 2d shows a sharp singlet at
δ 16.6 at room temperature, suggesting magnetically equiva-
lence of three phosphorus atoms. The H NMR spectrum
1
contains a slightly broad multiplet at δ 1.13 (27H) assignable
to three equivalent PMe3 protons, and all 2,6-dimethyl-
benzenethiolato signals also resonate equivalently at δ 2.55
(s, 12H), 6.97 (t, 2H), and 7.08 (d, 4H). No significant change
was observed in both variable temperature 1H and 31P{1H}
NMR spectra in the range of 20 to -70 °C. These features
show rapid fluxionality of 2d in solution as frequently obser-
ved for 5-coordinate compounds.22 When complex 2d was
treated with dry HCl gas in CD2Cl2, 2 equiv of 2,6-dimethyl-
benzenethiol were liberated, suggesting the presence of two
thiolato groups in 2d.
2. Molecular Structures of Bis(2,6-dimethylbenzenethiolato)-
ruthenium(II) Complexes. On cooling of a refluxing aceto-
nitrile solution of 2a to room temperature were produced dark-
purple plates suitable for X-ray analysis. Complex 2d showed
higher solubility toward most of organic solvents, and the
single crystals were obtained by the recrystallization from
cold toluene. These molecular structures are shown in Figure 2.
The overall molecular structures of 2a and 2d are 5-coordinate
bis(2,6-dimethylbenzenethiolato)ruthenium(II) complex with
three phosphorus donors. The axial thiolato S(1) and a phos-
phorus ligand P(2) are placed linearly [S(1)-Ru(1)-P(2):
173.3(1)° (2a), 176.76(11)° (2d)]. Meantime, while angles
S(1)-Ru(1)-P(1), S(1)-Ru(1)-P(3), S(1)-Ru(1)-S(2), P-
(1)-Ru(1)-P(2), and P(1)-Ru(1)-P(3) are nearly 90°, re-
spectively [2a, 83.8-94.97°; 2d, 81.92-95.24°], both angles
P(1)-Ru(1)-S(2) [2a, 134.0(6)°; 2d, 127.99(11)°] and P-
(3)-Ru(1)-S(2) [2a, 134.4(4)°; 2d, 137.02(12)°] are signifi-
cantly larger than 120°.23 Eisenstein and her co-workers
reported theoretical considerations for the structures of elec-
tron-deficient 5-coordinate d6 complexes (Chart 1), where the
electronic nature of the ligand X played an important role to
determine their structures by perturbing the dxy and dx2-y2
orbital:24 i.e. (i) a strong σ donor and good π acceptor ligand
favors square-pyramidal, (ii) a weak σ donor and good π
donor ligand favors distorted trigonal bipyramidal geometry
where the rest of equatorial ligands are squeezed each other,
and the L-M-L angle (R) in the xy plane inferiors to only
around 80°, and (iii) the role of the ligand perpendicular to
Figure 2. Molecular structures of Ru(SC6H3Me2-2,6-κ1S)2-
(TRIPHOS-κ3P,P0,P00) (2a) and Ru(SC6H3Me2-2,6-κ1S)2(PMe3)3
(2d). Ellipsoids represent 50% probability. All hydrogen atoms
are omitted for clarity.
the equatorial plane (on z axis) has been shown to be
negligible.
In the present case, one of the thiolato groups is placed in
the equatorial position and they are generally regarded as a
weak σ donor and good π donor ligand.25 In fact, the bond
˚
˚
distance Ru(1)-S(2) [2a, 2.34(2) A; 2d, 2.343(2) A] in the
equatorial position is significantly shorter than Ru(1)-S(1)
˚
˚
[2a, 2.447(1) A; 2d, 2.438(2) A] in the axial position and the
angle Ru(1)-S(2)-C(9) [2a, 121.2(6)°; 2d, 125.0(3)°] is larger
than Ru(1)-S(1)-C(1) [2a, 115.7(5)°; 2d, 118.9(3)°]. These
features suggest contribution of a sp2 hybridization of the
S(2) atom.26 The dihedral angles among S(1)-Ru(1)-
S(2)-C(9) [2a, 174.8(2)°; 2d, 178.2(4)°] and P(2)-Ru(1)-
S(2)-C(9) [2a, -9.7(2)°; 2d, -0.9(4)°] show the S(1), Ru(1),
P(2), S(2), and C(9) atoms being placed in almost the same xz
plane (Chart 2).
(22) (a) Crabtree, R. H. The Organometallic Chemistry of the Transi-
tion Metals, 3rd Ed.; Wiley: New York, 2001; pp 268. (b) Yamamoto, A.
Organotransition Metal Chemistry, Fundamental Concepts and Applica-
tions; Wiley: New York, 1986; pp 189.
(23) The P(1)-Ru(1)-S(2) angle is slightly smaller than the P(3)-
Ru(1)-S(2) angle for 2d, while they are comparable for 2a. The
reason for the favor of S(2) in 2d to be such biased position is not clear
so far.
ꢀ
(24) Riehl, J.-F.; Jean, Y.; Eisenstein, O.; Pelissier, M. Organometal-
lics 1992, 11, 729.
(25) Kamata, M.; Hirotsu, K.; Higuchi, T.; Tatsumi, K.; Hoffmann,
R.; Yoshida, T.; Otsuka, S. J. Am. Chem. Soc. 1981, 103, 5772.

3150 Organometallics, Vol. 29, No. 14, 2010
Hirano et al.
Chart 2. Preferred Orientation of the py Orbital
Chart 1. The Geometries of 5-Coordinate d6 Complexes and the
Energy Diagram
J = 349, 27, 23 Hz, 1P), 39.9 (ddd, J = 349, 19, 12 Hz, 1P),
47.1 (dd, J = 23, 12 Hz, 1P), and 90.2 (dd, J = 27, 19 Hz) in
C6D6. The signal appeared at the highest magnetic field at δ
-10.0 is assignable to the PMe3 ligand, and the large
coupling constant indicates the PMe3 locates trans to one
of the phosphorus atoms in TRIPHOS at δ 39.9. The lowest
resonance at δ 90.2 is assigned as the central PPh group
based on the analogy of 2a (δ 88.7).28 Therefore, the PMe3
and one of the terminal PPh2 groups in TRIPHOS are
1
considered to be mutually trans. In the H NMR spectrum
and COSY of the major species has two partly overlapped
multiplets at δ 2.5-2.6 (1H) and δ 2.88 (1H), assigned as
diastereotopic ortho methylene protons in the thiaruthena-
cycle moiety. These data show this thiaruthenacycle com-
pound to be either (OC-6-34)-1a or (OC-6-24)-1a (cf.
starting compounds in eqs 2 and 3). Although the stereo-
chemical configuration of this compound cannot be specified
on the basis of the spectroscopic data alone, we characterize
the major compound as (OC-6-34)-1a on the basis of the
following chemical reaction. Namely, hydrogenolysis of this
mixture by H2 (0.1 MPa) in benzene at 50 °C for 1 day
produced a corresponding (hydrido)(2,6-dimethylbenzen-
ethiolato)ruthenium(II) complex 8a in 60% yield whose
structure was characterized as described below.29
These facts mean that the occupied py orbital of the S(2)
atom is settled in the xy plane, and such orientation can be
explained by the interaction between the occupied py and the
empty dxy orbital in the xy plane, making a partial Ru-S
double-bond character. The corresponding R angles for 2a
(91.4(3)°) and 2d (92.47(13)°) are consistent with the electro-
nic feature of the thiolato ligand.
3. C-H Bond Cleavage Reaction of ortho Methyl
Group. 3.1. Phosphine Induced C-H Bond Cleavage Reac-
tion of Bis(2,6-dimethylbenzenethiolato)ruthenium(II) Having
a Tridentate or Bidentate Ligand. The TRIPHOS complex 2a
is formally a 16e coordinatively unsaturated compound and
is therefore expected to accept a 2-electron donor. Interest-
ingly, treatment of 2a with PMe3 does not give simple adduct
of a PMe3 ligand but produces thiaruthenacycle complexes
by the sp3 C-H bond cleavage reaction, which consist of two
stereochemical isomers of Ru[SC6H3(2-CH2)(6-Me)-κ2C,S]-
(TRIPHOS-κ3P,P0,P00)(PMe3) (1a) in 70% NMR yield as
shown in eq 1 ([(OC-6-34)-1a]/[(OC-6-25)-1a] = 80/20).27
The hydrogenolysis product shows a resonance at δ -6.81
(dddd, J = 95.8, 34.8, 19.2, 14.4 Hz, 1H) and a singlet at δ
3.03 (s, 6H) assignable to the hydrido and two equivalent
(26) A similar trend has been seen in the Ru-S bond distance in a
formally unsaturated complex Ru(SC6H3Me2-2,6-κ1S)2(η6-MeC6H4-
˚
CHMe2-4) (2.263 and 2.311 A) [ref 26a]. One the other hand, the Ru-S
˚
bonds in saturated complexes are relatively longer (2.429-2.476 A):
Ru(SC6H4Me-4-κ S)2(CO)2(PPh3)2 (2.470 A) [refs 26b and 26c], RuH-
1
˚
(SC6H4Me-4-κ1S)(CO)2(PPh3)2 (2.458 A) [ref 16], Ru(η5-C8H11)-
˚
(SC6H3Me2-κ1S)(PMe3)2 (2.476 A), and 1a (2.429 A) [ref 12]. (a)
Mashima, K.; Mikami, A.; Nakamura, A. Chem. Lett. 1992, 1473. (b)
Jessop, P. G.; Rettig, S. L.; James, B. R. J. Chem. Soc. Chem. Commun.
1991, 773. (c) Jessop, P. G.; Rettig, S. L.; Lee., C.-L.; James, B. R. Inorg.
Chem. 1991, 30, 4617.
˚
˚
They were isolated as an analytically pure isomeric mix-
ture in 51% yield, whose separation was unsuccessful by
recrystallization. The 31P{1H} NMR spectrum of the major
species shows four correlated resonances at δ -10.0 (ddd,

Article
Organometallics, Vol. 29, No. 14, 2010 3151
1
ortho methyl groups in the H NMR spectrum, suggesting
formation of a (hydrido)(2,6-dimethylbenzenethiolato)ruth-
enium(II) complex. In the 31P{1H} NMR spectrum, four
resonances are observed at δ -7.9 (dt, J = 283, 27 Hz, 1P),
35.3 (m, 1P), 64.2 (ddd, J = 283, 17, 5 Hz, 1P), and 105.7 (dd,
J = 29, 19 Hz, 1P), assignable to the PMe3, and PPh2, PPh2
and PPh fragments in the TRIPHOS ligand, respectively, by
the analogy of 1a and 4a. The large coupling constant
between the PMe3 and one of the PPh2 fragments suggests
mutually trans configuration of these phosphorus atoms.
The other PPh2 fragment at (δ 35.3) shows characteristic
upfield shift compared with the corresponding resonance of
the starting thiaruthenacycle 1a (δ 47.1), although the other
signals shift to the downfield. Because the hydrido ligand is
generally known to show strong trans influence,30 this up-
field shift strongly suggests this PPh2 fragment being settled
in trans to the hydrido. Therefore, this product is considered
to be (OC-6-34)-8a, suggesting the starting compound as
(OC-6-34)-1a ((eq 2).
Scheme 2
On the other hand, the minor species (OC-6-25)-1a can be
characterized as follows. The 31P{1H} NMR spectrum of
minor thiaruthenacycle 1a has correlated resonances at
δ -16.6 (ddd, J = 360, 24, 22 Hz, 1P), 50.9 (ddd, J = 22,
10, 5 Hz, 1P), 73.6 (m, 1P), and 89.9 (ddd, J = 360, 30, 10 Hz,
1P). The signals at δ -16.6 and 89.9 are assignable to the
PMe3 and the central PPh moiety in TRIPHOS, respectively,
and their large coupling constant suggests that they are
mutually trans. Therefore, we characterized the minor thiar-
uthenacycle species to be (OC-6-25)-1a.
sp3 C-H bond cleavage in the ortho methyl group than 2a. In
fact, the reaction of 2d with PMe3 proceeded within 20 min in
benzene even at room temperature to give 1d in 95% yield
with concomitant formation of 2,6-dimethylbenzenethiol
(91%) (Scheme 2).
Quantitative formation of 1d was also observed in THF
and acetone. Interestingly, when methanol was employed as
a solvent in this reaction, a bis(2,6-dimethylbenzenethio-
lato)tetrakis(phosphine)ruthenium(II) complex, cis-Ru-
(SC6H3Me2-2,6-κ1S)2(PMe3)4 (3d) was exclusively produced
instead of 1d (eq 4). It is notable that 3d never causes C-H
bond cleavage reaction to give 1d in methanol at all. All
attempts to isolate 3d from the methanol solution resulted in
failure but gave 2d, suggesting facile dissociation of PMe3
from 3d. Probably, one of the PMe3 ligands in 3d was
removed during the isolation process. Complex 3d was
therefore characterized by the spectroscopic methods as
follows.
Contrary to PMe3, neither PPh3 nor PBu3 reacted with 2a
under the similar conditions. This is probably due to steric
congestions around the ruthenium center.
The reaction of a TDPME complex 2b with 5 equiv of
PMe3 in C6D6 at 50 °C resulted in the displacement of the
TDPME ligand to PMe3, giving cis-Ru[SC6H3(2-CH2)(6-
Me)-κ2C,S](PMe3)4 (1d) (54%) with concomitant formation
of 2,6-dimethylbenzenethiol (71%) and free TDPME (70%).
Such phosphine exchange reaction also proceeded even in
the reaction of 2b with 1 equiv of PMe3 to give 1d in 10%
yield.
On the other hand, no reaction took place when a biden-
tate DPPE complex 3c was treated with 10 equiv of PMe3 in
DMSO-d6 at 70 °C for 32 h. This is probably because
complex 3c is a coordinatively saturated compound and
two 2,6-dimethylbenzenethiolato groups are mutually trans.
Both factors may discourage the C-H bond cleavage pro-
cess from 3c.
3.2. Reactions of Bis(2,6-dimethylbenzenethiolato)ruthen-
ium(II) Having PMe3 Ligands. Complex 2d shows more facile
(27) The stereochemical description is based on the 1990 IUPAC
Inorganic Rules : Block, B. P.; Powell, W. H.; Ernelius, W. C. Inorganic
Chemical Nomenclature: Principles and Practice, ACS Professional
Reference Book; American Chemical Society, Washington, DC, 1990;
pp 143.
(28) This assignment is made based on the chemical shift comparisons
to the starting compounds 2a and 4a because the central PPh fragment
was observed in characteristic low field. Although this trend is general
feature in the 31P{1H} NMR spectra of the octahedral TRIPHOS
complexes, we cannot rule out unexpected upfield shift of the central
PPh in 1a. cf. George, T. A.; Tisdale, R. C. J. Am. Chem. Soc. 1985, 107,
5157.
(29) Because separation of these stereochemical isomers was difficult,
the isomeric mixture was employed for the hydrogenolysis reaction. The
reaction completely proceeded but the hydride species corresponding to
the minor species was not observed at all.
(30) Crabtree, R. H. The Organometallic Chemistry of the Transition
Metals, 3rd Ed.; Wiley: New York, 2001; pp 6.
In the 31P{1H} NMR spectrum of 3d in methanol-d4, two
triplets are observed at δ 15.67 (t, J = 29 Hz, 2P) and -10.79
(t, J = 29 Hz, 2P), suggesting an A2X2 spin system due to
presence of two equivalent ligands in cis fashion in the
octahedral geometry. The 1H NMR spectrum involves a
virtual triplet at δ 1.61 (18H) and a slightly broad singlet at δ
1.52 (18H) assignable to the mutually trans PMe3 and PMe3
trans to S, respectively. The ortho methyl groups in 2,6-
dimethylbenzenethiolato groups appear at δ 1.57 (s, 6H) and
2.40 (s, 6H) with resonances due to two different aromatic

3152 Organometallics, Vol. 29, No. 14, 2010
Hirano et al.
groups.31 Introduction of dry HCl gas to 3d in methanol
liberated 2,6-dimethylbenzenethiol in 203% yield, clearly
indicating presence of two 2,6-dimethylbenzenethiolato
groups. It is noteworthy that 3d has never been observed
by the treatment of 2d with PMe3 in benzene. High polarity
and/or hydrogen bonding may stabilize 3d in methanol. To
know the relation between the employed solvent and the
product, we studied the reaction of 2d with PMe3 in several
polar solvents. In dichloromethane, addition of PMe3 to 2d
gave both 1d (15%) and 3d (69%) in 90% conversion of 2d at
30 °C for 10 min. These yields were not changed when the
mixture was left for 20 h. A similar result was also obtained in
chloroform, where the treatment of 2d with PMe3 produced
both 1d (48%) and 3d (10%). Right after addition of 3 equiv
of PMe3 to 2d at 30 °C in DMSO, a mixture of 2d (34%), 3d
(42%), and 1d (13%) was obtained. Then, 2d and 3d slowly
decreased with increase of 1d and 2,6-dimethylbenzenethiol.
After 11 h at 30 °C, the reaction system constituted of a
steady state mixture of 2d (4%), 3d (10%), 1d (73%), and 2,6-
dimethylbenzenethiol (88%).
Chart 3
at δ 1.20 (18H) in the 1H NMR spectrum suggest the
meridional geometry of 3e (Chart 3).
The 1H NMR spectrum also shows a broad singlet around
δ 2.45-2.50 (12H) and a broad peak at δ 11.5 (2H), assign-
able to the four ortho methyl groups and an aqua ligand,
respectively. These data support the formation of 3e. The
aqua ligand probably comes from contaminated water in this
system. Similar treatment of 2d with PEt3 produced a com-
plex mixture involving 1d (17%) and 3e (5%) with concomi-
tant formation of 2,6-dimethylbenzenethiol. In this reaction,
a PMe3 ligand probably came from another 2d by dispro-
portionation reaction to give 1d. It seems that addition of
compact phosphorus ligands to 2d leads to the C-H bond
cleavage reaction to give thiaruthenacycle complexes.32 On
the other hand, exposure of 2d to CO (0.1 MPa) quickly produced
an analytically pure carbonyl complex cis,cis,cis-Ru(SC6H3Me2-
2,6-κ1S)2(PMe3)2(CO)2 (cis,cis,cis-3h) in 93% yield as a kinetic
product, which finally gave an equilibrium mixture between cis,
cis,cis-3h and trans,trans,trans-3h (Keq = [trans,trans,trans-
3h]/[cis,cis,cis-3h] = 9.9 at 50 °C in benzene) (Scheme 3).
The stereochemistry of these isomers was determined by
the NMR data, where cis,cis,cis-3h showed two magnetically
inequivalent 2,6-dimethylbenzenethiolato moieties in the 1H
NMR and an AX pattern appeared at δ -16.09 (d) and
-11.46 (d) in the 31P{1H} NMR, and trans,trans,trans-3h
gave a sole 2,6-dimethylbenzenethiolato resonance and a
virtual triplet at δ1.08 (vt, 18H) assignable to the PMe3 in the
1H NMR, and a single resonance δ -14.81 in the 31P{1H}
NMR. These spectroscopic data suggests proposed struc-
tures of 3h.
Several two-electron donors were added to a benzene
solution of 2d in order to understand the effect of ligand
on the formation of 1d (Scheme 2). When P(OMe)3 was
added to 2d, a thiaruthenacycle complex, cis,trans,cis-Ru-
[SC6H3(CH2-2)(Me-6)-κ2S,C](PMe3)2[P(OMe)3]2 (1f) was
produced in quantitative yield. An AMX2 pattern at δ 156.8
(1P, P(OMe)3), 100.7 (1P, P(OMe)3) and 3.5 (2P, PMe3) in the
31P{1H} NMR and a virtual triplet at δ 1.47 (18H) in the 1H
NMR support this configuration, and a broad peak at δ 2.5
1
(2H) and a singlet at δ 1.86 (3H) in the H NMR suggest
formation of thiaruthenacycle 1f. Similarly, addition of PMe2Ph
to 2d gave a 6:4 mixture of regioisomers of mer-Ru[SC6H3-
(CH2-2)(Me-6)-κ2S,C](PMe3)3(PMe2Ph) (1g) in 31% yield
with concomitant formation of 2,6-dimethylbenzenethiol in
36% yield. The major isomer shows an AM2X pattern at δ
0.16 (1P, PMe2Ph), -8.32 (2P, PMe3), and -16.7 (1P, PMe3)
in the 31P{1H} NMR and an overlapped signals at δ 2.9 and a
triplet of triplets at δ 2.75 (2H) in the 1H NMR assignable to
the ortho methyl and methylene groups, respectively, sugges-
ting formation of a thiaruthenacycle 1g. Similarly, the minor
isomer shows an AM2X pattern at δ 9.35 (1P, PMe2Ph),
-9.62 (2P, PMe3), and -17.60 (1P, PMe3) in the 31P{1H}
NMR and a triplet of triplets at δ 3.11 (2H) and an over-
lapped signal at δ 2.9 (3H) in the 1H NMR, assignable to the
ortho methylene and methyl groups, respectively, suggesting
formation of thiaruthenacycle 1g. In these 31P{1H} NMR
spectra, the PMe2Ph in the major isomer resonates at the
higher magnetic field (δ 0.16) than that in the minor isomer
(δ 9.35), strongly suggesting that the PMe2Ph ligand is placed
trans to the carbon ligand with strong trans influence. There-
fore, we characterize the major species to be (OC-6-34)-1g
(the PMe2Ph trans to methylene) and the minor species to be
(OC-6-24)-1g (the PMe2Ph trans to S). Treatment of 2d with
PCy3 gave a mixture involving cis,mer-Ru(SC6H3Me2-
κ1S)2(PMe3)3(OH2) (3e) (48%). An AX2 pattern at δ 39.68
(1P) and -3.58 (2P) in the 31P{1H} NMR and a virtual triplet
3.3. Reversibility of the C-H Bond Cleavage Reaction.
Treatment of a mixture of thiaruthenacycle complexes (OC-
6-34)-1a and (OC-6-25)-1a, with 2 equiv of 2,6-dimethyl-
benzenethiol in benzene at 70 °C for 3 days gave a bis(2,6-
dimethylbenzenethiolato)ruthenium(II) complex 2a in 83%
yield (eq 5).
Similarly, the reaction of 1d with 5 equiv of 2,6-dimethyl-
benzenethiol in acetone at room temperature for 15 h
produced 2d, which was isolated as analytically pure dark-
red needles in 32% yield after recrystallization from cold
toluene. With 15 equiv of 2,6-dimethylbenzenethiol in acet-
one, 2d was formed in 57% in 30 min (Scheme 4). When
similar treatment was performed in benzene, 2d was formed
(31) One of the ortho methyl resonances in 9d appears in significantly
high field at δ 1.57, while another ortho methyl group resonates at the
comparable region to the related cis-bis(2,6-dimethylbenzenethio-
lato)ruthenium(II) complexes such as 2a (δ 2.11), 2b (δ 2.46), 2d (δ
2.55), and free 2,6-dimethylbenzenethiol (δ 2.48). Because 9d is a
coordinatively unsaturated complex, this fact may be caused by the lone
pair electrons on the S atom attached to the saturated Ru center, or the
ring current effect of the aromatic ring.
(32) Cone angles: P(OMe)3 (107°), PMe3 (118°), PMe2Ph (122°), PEt3
(132°), PPh3 (145°) and PCy3 (170°). Tolman, C. A. Chem. Rev. 1977, 77,
313.

Article
Organometallics, Vol. 29, No. 14, 2010 3153
Scheme 3
Scheme 4
in only 12% yield. In methanol, 3d was produced in 60%
yield as a major product along with 2d in 27% yield. These
results show reversibility of the present C-H bond cleavage
reaction but the reaction strongly depends on the solvent.
4. Kinetic Study for the C-H Bond Cleavage Reaction.
Complex 2d shows an absorption band at 518 nm (ε = 2530
M-1 cm-1) in benzene. When excess PMe3 was added, the
band gradually decreased and finally gave the absorption
spectrum identical to 1d. Though isosbestic points were not
observed, the absorption band homogeneously decreased
with time and the reaction was first-order on the concentra-
tion of 2d. The observed rate constant kobs was estimated as
2.63 ( 0.03 ꢀ 10-3 s-1 in the presence of 45 equiv of PMe3 at
30 °C, and the estimated first-order rate constant was indep-
endent from the concentration of PMe3 (Figure 3).
Figure 3. Effect of added PMe3 on the first-order rate constant
kobs monitored by the UV-vis spectral change at 518 nm for
conversion of 2d into 1d in benzene at 30.0 ( 0.5 °C. Conditions:
[2d] = 0.94 mM.
more than 3 half-lives, although this reaction produced two
stereoisomers (OC-6-34)-1a and (OC-6-25)-1a. This reac-
tion also depends on neither concentration of added PMe3
nor potassium 2,6-dimethylbenzenethiolate. The reaction
rate in THF [(1.68 ( 0.02) ꢀ 10-5 s-1] is also slower than
that in nonpolar toluene [(6.16 ( 0.06) ꢀ 10-5 s-1].
Therefore, the rate for the conversion of 2d into 1d is
expressed as shown in eq 6.
Tris(trimethylphosphine) complex of bis(2,6-dimethyl-
benzenethiolato)ruthenium(II) 2d was shown to produce
corresponding tetrakis(trimethylphosphine) complex 3d
quantitatively by addition of PMe3 in methanol, while such
treatment in benzene led to the C-H bond cleavage reaction,
giving a thiaruthenacycle complex 1d, exclusively. To clarify
the potential ability of the coordinatively saturated complex 3d
for the C-H bond cleavage reaction to give the ruthenacycle,
time-course for the formation of the ruthenacycle 1d was
monitored in DMSO-d6 by NMR at 30 °C in the presence of
PMe3 because 3d was obtained along with 1d by the treatment
of 2d with PMe3 in DMSO (vide supra). After mixing 1d and 1,
3, and 10 equiv of PMe3 at 30 °C, the ratios of 2d/3d reached
61%/23%, 34%/42%, and 15%/73%, respectively. The half-
lives at 30 °C increased as follows: t1/2 = 0.64 h (1 equiv PMe3),
1.4 h (3 equiv PMe3), 2.2 h (10 equiv PMe3). This feature
suggests the rate for the formation of 1d, becoming slower
along with increase of concentration of 3d, although quanti-
tative kinetic studies have not been performed. Therefore, 3d is
considered to be inert to the C-H bond cleavage reaction. The
most probable scenario is that the C-H bond cleavage reac-
tion from 2d competes the formation of 3d in the presence of
PMe3 in DMSO, and the C-H bond cleavage reaction takes
place only from 2d (Scheme 5). Probably, polar and apolar
solvents favor to give 3d and 1d in this reaction, respecti-
vely. The present consideration also suggests importance of
d½2dꢁ
0
-
¼ kobs½2dꢁ ¼ k1½PMe3ꢁ ½2dꢁ
ð6Þ
dt
1
Conversion of 2d into 1d was also confirmed by the H
NMR spectra in C6D6 in the presence of 3 equiv of PMe3 at
30 °C and the estimated first-order rate constant was kobs
=
2.7 ꢀ 10-3 s-1, which was comparable to that monitored by
the UV-vis spectra. The estimated rate constant depends on
the employed solvent and decreased in the order benzene:
(2.78 ( 2) ꢀ 10-3 s-1 > THF: (1.10 ( 1) ꢀ 10-3 s-1 > ace-
tone: (3.67 ( 0.5) ꢀ 10-4 s-1. Therefore, the rate constant is
considered to decrease with increase of dielectric constant of the
used solvent: benzene (ε = 2.28) < THF (ε = 7.32) < acetone
(ε = 20.7).33 This reaction was not affected by the addition of
galvinoxyl and potassium 2,6-dimethylbenzenethiolate.
For the bis(2,6-dimethylbenzenethiolato)ruthenium(II)
complex with a tridentate phosphine ligand 2a, the absorp-
tion maximum was at 573 nm (ε = 1690 M-1cm-1) in THF
whose intensity also decreased after addition of PMe3, sug-
gesting formation of 1a. The rate of disappearance of 2a also
showed a good linearity in the first-order rate plot in THF for
(33) Gordon, A. J.; Ford, R. A. The Chemist’s Companion: A Hand-
book of Practical Data, Techniques, and References; Wiley: New York,
1972; pp 6.

3154 Organometallics, Vol. 29, No. 14, 2010
Hirano et al.
Scheme 5
Scheme 6
Figure 4. Eyring plot for the intramolecular C-H bond cleav-
age reaction of 2d to give 1d in benzene.
5-coordinate formally unsaturated compounds for the C-H
bond cleavage reaction in Ru(II).
to be the rate-determining, (iv) the rate-determining step in the
formation of 1d favors nonpolar solvents, suggesting the less
polar transition state than the ground state, (v) a radical
scavenger such as galvinoxyl does not retard this process that
rules out a free radical process, (vi) because no significant
difference in the rate is observed in the presence of 2,6-di-
methylbenzenethiolate anion, neither prerequisite dissociation
of thiolato anion nor proton abstraction by thiolato anion is a
favorable process, and (vii) the large negative entropy of acti-
vation suggests a distorted transition state.
As described above, 2d is responsible for the C-H bond
cleavage reaction to give 1d. Although this reaction requires
addition of PMe3, present kinetic data suggests the forma-
tion rate constant of 1d is independent of the concentration
of PMe3. We therefore proposed a tris(trimethylphosphine)
complex A as an intermediate to which PMe3 coordinated
rapidly to give 1d. (Scheme 6).
Because such an intermediate A has never been detected
during the formation of 1d, we apply the steady state
approximation to the concentration of A, giving the rate
equation expressed as shown in eq 7.
From these facts, the rate-determining step in the present
reaction would therefore be the C-H bond cleavage step by
concerted mechanisms as shown in Scheme 7.
- ðd½2dꢁÞ=ðdtÞ ¼ ðk1k2½2dꢁ½PMe3ꢁ
Route 1 involves a four-centered transition state either via
a σ-bond metathesis or an internal electrophilic substitution.
Because they closely resemble each other and it is difficult to
experimentally differentiate these mechanisms, we summar-
ize these two mechanism into a four-centered concerted mec-
hanism. Route 2 involves a three-centered transition state
that is so-called the C-H bond oxidative addition mechan-
ism followed by the reductive elimination between the thio-
lato and hydrido ligands. Although we do not have definitive
evidence in support of either mechanism yet, we believe that
the reaction through route 1 is the favorable scenario because
route 2 requires a 7-coordinate Ru(IV) intermediate A2,
which is expected to be a high-energy process.34 In route 1
in Scheme 7, it is reasonable to postulate an equilibrium bet-
ween 2 and intermediate A. An alternative structure of inter-
mediate A is a 5-coordinate species Ru[SC6H3(2-CH2)(6-
Me)-κ2S,C](PMe3)3. However, the large negative entropy of
activation suggests the thiol moiety remaining intact on the
ruthenium center. Thus intermediate A is considered to be a
thiaruthenacycle with a 2,6-dimethylbenzenethiol ligand,
from which the thiol ligand is rapidly displaced by PMe3 to
give 1.
- k- 1k- 2½1dꢁ½HSC6H3Me2 - 2, 6ꢁ½PMe3ꢁÞ=
ðk- 1 þ k2½PMe3ꢁÞ
ð7Þ
On the basis of the experimental results, we assumed that
(i) the pre-equilibrium between 2d and A in Scheme 6 lay far
to the 2d side, (ii) formation of A was the rate-determining
step, and (iii) the back reaction from 1d with 2,6-dimethyl-
benzenethiol was a slow process. Then, eq 7 is simplified as
eq 8, which is consistent with the experimental rate equation
(eq 6).
d½2dꢁ
-
¼ k1½2dꢁ
ð8Þ
dt
5. Proposed Mechanism for the C-H Bond Cleavage Re-
action. To get information of the transition state, the kinetic
parameters for 2d are estimated by the Eyring plot for the
reaction in benzene in the range of 30-50 °C (Figure 4):
ΔHq = 57 ( 16 kJ mol-1, ΔGq298 = 89 ( 31 kJ mol-1, and
ΔSq = -107 ( 51 J mol-1 K-1
.
Similarly, the kinetic activation parameters of 2a in THF
are as follows: ΔHq= 87 ( 14 kJ mol-1, ΔGq298 = 70 ( 27 kJ
mol-1, and ΔSq = -58 ( 42 J mol-1 K-1. Those of 2a in
toluene show similar parameters of activation: ΔHq = 85 ( 5
kJmol-1, ΔGq298 = 104 (10kJmol-1, andΔSq = -65 (14J
Concluding Remarks
mol-1 K-1
.
We have reported synthesis of 5-coordinate bis(2,6-
dimethylbenzenethiolato)ruthenium(II) complexes, which
readily give corresponding thiaruthenacycle complexes by
addition of PMe3 ligand. The sp3 C-H bond cleavage
reaction from bis(2,6-dimethylbenzenethiolato)ruthenium-
(II) complexes 2 proceeds by the concerted mechanism and
Results of reactivities of bis(2,6-dimethylbenzenethiolato)-
ruthenium(II) complexes and kinetic studies for the formation
process of thiaruthenacycle complexes 1 are summarized as
follows: (i) neither cis-Ru(SC6H3Me-2,6-κ1S)2(PMe3)4 (3d)
nor trans-Ru(SC6H3Me2-2,6-κ1S)2(dppe)2 (3c) converts into
the thiaruthenacycle 1, suggesting the importance of coordi-
native unsaturation for the C-H bond cleavage reaction, (ii)
the first-order dependence of the rate on the concentration of 2
that rules out a C-H bond cleavage via bimolecular process,
(iii) the zero-order dependence of the PMe3 concentration on
the rate suggests that formation of A in Scheme 6 is considered
(34) We have found Brønsted acid promote the C-H bond cleavage
reaction in aryloxoruthenium(II) complex. The present C-H bond
cleavage reaction from 2 in the presence of Brønsted acid will be reported
elsewhere. Hirano, M.; Kuga, T.; Kitamura, M.; Kanaya, S.; Komine,
N.; Komiya, S. Organometallics 2008, 27, 3635.

Article
Organometallics, Vol. 29, No. 14, 2010 3155
Scheme 7
1
the coordinative unsaturation is an intrinsic factor for pre-
sent C-H bond cleavage reaction. It is also notable that the
activation energy for the present sp3 C-H bond cleavage
reaction is approximately one-fourth of the bond dissocia-
tion energy for the sp3 C-H bond in toluene.35 This fact sug-
gests the methyl group C-H bond in bis(2,6-dimethylbenz-
enethiolato)ruthenium(II) complex being activated probably
due to the interaction with the sulfur atom in the arenethio-
lato group, which also acts as a good acceptor of the cleaved
proton.
KOH in methanol. H and 31P{1H} NMR spectra were mea-
sured on a JEOL LA300 and a JEOL ECX400 spectrometers.
The IR spectra were measured on a JASCO FT/IR410 spectro-
meter. UV-vis spectra were measured on a Shimadzu UV-Spec
1500 photodiode array spectrometer using a thermostatted
Schlenk type quartz cell. Elemental analyses were performed
on Perkin-Elmer 2400 series II CHN analyzer. The compounds
without the elemental analysis were characterized by the spectro-
scopic methods. For thermodynamic and kinetic analyses, reli-
ability intervals indicate 95% probability.
Ru(SC6H3Me2-2,6-K1S)2(TRIPHOS-K3P,P0,P00) (2a). Com-
plex 5 (371.6 mg, 1.18 mmol) was treated with TRIPHOS (621.7
mg, 1.163 mmol) in benzene (22 mL) for 2 days at room
temperature. All volatile matters were removed under reduced
pressure. Recrystallization of the resulting solid from refluxing
toluene gave yellow plates of Ru(η4-1,5-COD)(TRIPHOS-κ3P,
P0,P00) C6H5Me (4a C6H5Me) in 89% yield (777.6 mg, 1.045
Experimental Section
General Procedure. All procedures described in this paper
were carried out under nitrogen or argon atmosphere by use of
Schlenk and vacuum line techniques. Benzene, hexane, toluene,
and Et2O were dried over dry calcium chloride and were distilled
over sodium wire under nitrogen using benzophenone ketyl as
an indicator. THF was distilled over sodium wire under nitrogen
in the presence of benzophenone. Acetone was dried over
Drierite and distilled under nitrogen. Methanol was dried over
molecular sieves 4A and then was distilled over magnesium
methoxide. 2,6-Dimethylbenzenethiol was purchased from Al-
drich and was stored and used under nitrogen atmosphere.
PMe3 was prepared by the reaction of P(OPh)3 with MeMgI
and was distilled under vacuum.36 cis-Ru[SC6H3(CH2-2)(Me-
6)-κ2S,C](PMe3)4 (1d) was prepared as reported previously.18
Ru(1,5-COD)(1,3,5-COT) (5),37 Ru(η6-naphthalene)(η4-1,5-
COD) (6),38 RuCl2(PPh3)3,39 trans-RuCl2(DPPE)2 (7c),40 and
trans-RuCl2(PMe3)4 (7d),41 were prepared according to the
literature methods. Potassium salt of 2,6-dimethylbenzenethiol
was prepared by the treatment of 2,6-dimethylbenzenethiol with
3
3
1
mmol). 4a: H NMR (300 MHz, C6D6) δ 1.0-1.2 (br m, 2H,
CH2 in TRIPHOS), 1.6-2.0 (m, 4H, CH2 in TRIPHOS), 2.2 (br
s, 8H, COD), 2.4 (m, 1H, CH2 in TRIPHOS), 2.5 (m, 1H, CH2 in
TRIPHOS), 2.7-4.0 (very broad, COD, 4H), 6.8-7.3 (m, 24H,
Ph), 7.39 (t, 3JH-H = 7 Hz, 4H, Ph), 7.82 (t, 3JH-H = 7 Hz, 4H,
Ph). 13C{1H} (100.5 MHz, C6D6) δ 31.0-31.5 (br m, TRIPHOS),
32.9-33.9 (br m, TRIPHOS), 125.6 (s, TRIPHOS), 128.6 (s,
1J = 143 Hz, TRIPHOS), 129.3(s, TRIPHOS), 130.8(d, 1JC-P
=
8 Hz, TRIPHOS), 132.7 (q, 1JC-P = 3JC-P = 7 Hz, TRIPHOS),
137.8 (s, TRIPHOS), 141.6 (s, TRIPHOS), 147.1 (s, TRIPHOS)
signals due to the 1,5-COD ligand were obscure. 31P{1H} NMR
(122 MHz, C6D6) δ 75.8 (d, J = 24 Hz, 2P), 102.8 (t, J = 24 Hz,
1P). Anal. Calcd for C42H45P3Ru C7H8: C, 70.04; H, 6.39.
3
Found: C, 70.75; H, 6.85. 4a C6H5Me (324.5 mg, 0.4363 mmol)
3
was treated with 2,6-dimethylbenzenethiol (300 μL, 2.25 mmol) in
acetonitrile (15 mL) at 70 °C for 6 h. On cooling the solution to
room temperature, dark-purple plates of 2a deposited. Yield: 88%
(347.8 mg, 0.382 mmol). 1H NMR (300 MHz, CD2Cl2) δ 1.61 (m,
2H, CH2 in TRIPHOS), 1.85 (m, 2H, CH2 in TRIPHOS), 2.11
(overlapped, br, 12H, ortho-Me), 2.18 (overlapped, m, 2H, CH2 in
TRIPHOS), 2.49 (m, 2H, CH2 in TRIPHOS), 6.43 (br, 6H,
aromatic protons), 6.8-8.1 (m, 25H, aromatic protons). 31P{1H}
(122 MHz, CD2Cl2) δ 81.5 (d, J = 15 Hz, 2P), 88.7 (t, J = 15 Hz,
1P). Anal. Calcd for C50H51P3RuS2: C, 65.99; H, 5.65; S, 7.05.
Found: C, 65.59; H, 5.77; S, 7.61. UV-vis (THF): λmax = 573 nm
(ε = 1690).
(35) Luo, Y.-R. Handbook of Bond Dissociation Energies in Organic
Compounds; CRC: New York, 2003; pp 31, .
(36) Kosolapoff, G. M.; Maier, L. In Organic Phosphorus Com-
pounds, Vol. 1; Wiley: New York, 1972; p 32.
(37) Itoh, K.; Nagashima, H.; Ohshima, T.; Oshima, N.; Nishiyama
J. Orgnaomet. Chem. 1984, 272, 179.
(38) Bennett, M. A.; Neumann, M.; Thomas, M.; Wang, X.-Q
Organometallics 1991, 10, 3237.
(39) Hallman, P. S.; McCarvey, B. R.; Wilkinson, G. J. Chem. Soc., A
1968, 3143.
€
Ru(SC6H3Me2-2,6-K1S)2(TDPME-K3P,P0,P00) (2b). Complex
6 (65.4 mg, 0.194 mmol) and TDPME (120 mg, 0.192 mmol)
were placed in an Schlenk tube (25 mL). Benzene (3 mL) was
added into the Schlenk tube, and the solution was heated at
(40) Rohr, M.; Gunther, M.; Jutz, F.; Grunwaldt, J.-D.; Emerich, H.;
Beek, W. V.; Baiker, A. Apl. Catal., A 2005, 296, 238.
(41) Jones, R. A.; Real, F. M.; Wilkinson, G.; Galas, A. M. R.;
Hursthouse, M. B.; Malik, K. M. A. J. Chem. Soc., Dalton Trans. 1980,
511.

3156 Organometallics, Vol. 29, No. 14, 2010
Hirano et al.
70 °C for 2 days. After removal of benzene, the free naphthalene
was removed by use of an oil diffusion pump. The resulting solid
was washed with acetone and then it was recrystallized from
cold toluene to give a yellow powder of Ru(η4-1,3-COD)-
(TDPME-κ3P,P0,P00) (4b) in 53% yield (85.5 mg, 0.103 mmol).
1H NMR (300 MHz, C6D6) δ 1.11 (s, 3H, Me in TDPME), 1.7
(br, 2H, 1,3-COD), 1.8 (br, 2H, 1,3-COD), 2.11 (s, 6H, CH2 in
TDPME), 2.4 (br, 2H, 1,3-COD), 2.6 (br, 2H, 1,3-COD), 3.14
(br, 2H, 1,3-COD), 5.25 (t, J = 11 Hz, 2H, 1,3-COD), 6.8-7.2
(m, 30H, Ph). 31P{1H} NMR (122 MHz, C6D6) δ 31.2 (s). Anal.
Calcd for C49H51P3Ru: C, 70.57; H, 6.16. Found: C, 70.02; H,
6.24. It is notable that the 1,3-COD ligand is produced from 1,5-
COD by isomerization during the isolation process because the
NMR spectra of crude product are assigned as Ru(η4-1,5-
was added as an internal standard, and then PMe3 (1.3 μL,
0.015 mmol) was added by a hypodermic syringe. After 50 min, 1d
was produced in 98% yield.
Treatment of 2d with PMe3 in Methanol-d4. Complex 2d
(6.3 mg, 0.010 mmol) was placed in a NMR tube into which
CD3OD (600 μL) was introduced by a hypodermic syringe.
PMe3 (2.9 μL, 0.028 mmol) was added into the solution by a
hypodermic syringe. The time-course of the reaction was moni-
tored by the NMR spectra at 30 °C. After 20 min, 2d was
completely consumed and cis-Ru(SC6H3Me2-2,6-κ1S)2(PMe3)4
(3d) was produced in 100% yield. Complex 3d could not be
isolated because during the isolation process; 3d converted to 2d,
probably due to facile dissociation/evaporation of a PMe3
ligand. Therefore 3d was characterized spectroscopic methods.
1
1
COD)(TDPME) (4b0). 4b0: H NMR (300 MHz, C6D6) δ 1.06
3d: H NMR (300 MHz, CD3OD, 30 °C) δ 1.52 (br s, 18H,
PMe3), 1.57 (s, 6H, ortho-Me), 1.61 (vt, 2JH-P = 4JH-P = 3.6 Hz,
18H, PMe3), 2.40 (s, 6H, ortho-Me), 6.58 (t, 3JH-H = 7.3 Hz, 1H,
para-C6H3Me2), 6.79 (t, JH-H = 6.9 Hz, 1H, para-C6H3Me2),
(s, 3H, Me in TDPME), 2.18 (s, 8H, CH2 in 1,5-COD), 2.62 (d,
J = 8.2 Hz, 3H, CH2 in TDPME), 2.8 (d, J = 8.2 Hz, 3H, CH2 in
TDPME), 3.41 (s, 4H, CH in 1,5-COD), 6.8-7.4(m, Ph, 30H).
31P{1H} NMR (122 MHz, C6D6) δ 32.1 (s). 4b (110.4 mg,
0.1324 mmol) was treated with 2,6-dimethylbenzenethiol (90 μL,
0.68 mmol) in benzene at 70 °C for 24 h. Then, all volatile matter
was removed under reduced pressure and the resulting solid was
recrystallized from refluxing toluene to give 2b as black needles
in 53% yield (70.0 mg, 0.0702 mmol). 1H NMR (300 MHz,
C6D6) δ 1.06 (s, 3H, Me in TDPME), 2.18 (s, 6H, CH2 in
TDPME), 2.46 (s, 12H, ortho-Me), 6.7-7.0 (m, 24H, aromatic
protons), 7.53 (s, 12H, aromatic protons). 31P{1H} NMR (122
MHz, C6D6) δ40.5 (s). Anal. Calcd for C57H57P3RuS2: C, 68.45; H,
5.74; S, 6.41. Found: C, 68.47; H, 5.74; S, 6.24. UV-vis (THF):
3
6.84 (d, 3JH-H = 7.3 Hz, 2H, meta-C6H3Me2), 6.92 (d, 3JH-H
=
6.9 Hz, 2H, meta-C6H3Me2). 31P{1H} NMR (162 MHz, CD3OD,
2
30 °C) δ -10.79 (t, JP-P = 29 Hz, 2P, mutually trans PMe3),
15.67 (t, 2JP-P = 29 Hz, 2P, PMe3 trans to S).
Protonolysis of 3d with Dry HCl. Because complex 3d was not
isolable compound, this reaction was carried out by use of in situ
formed 3d in an NMR tube. Treatment of 2d (6.8 mg, 0.011
mmol) with 3 equiv of PMe3 (3.5 μL, 0.034 mmol) in methanol-
d4 produced 3d quantitatively, which was confirmed by the
NMR spectra. The reaction system was exposed to dry HCl to
give 2,6-dimethylbenzenethiol in 203% yield (0.023 mmol).
Treatment of 2d with PMe3 in Dimethylsulfoxide-d6. Complex
2d (5.5 mg, 0.0091 mmol) and a flame-sealed ampule containing
P(OPh)3 in C6D6 as an standard were placed in an NMR tube
into which DMSO-d6 (600 μL) was introduced by a hypodermic
syringe. Triphenylmethane (2.7 mg, 0.011 mmol) was added as
an internal standard. PMe3 (2.5 μL, 0.024 mmol) was added into
the NMR tube by a hypodermic syringe, and the reaction profile
was monitored at 30 °C by NMR. After 11 h, 1d (0.0066 mmol,
73%), 3d (0.0009 mmol, 10%), and 2,6-dimethylbenzenethiol
λ
max = 432 nm (ε = 2990), 620 nm (ε = 1650).
trans-Ru(SC6H3Me2-2,6-K1S)2(DPPE)2 (3c). Complex 7c
(183.4 mg, 0.1893 mmol) and potassium salt of 2,6-dimethyl-
benzenethiol (97.9 mg, 0.555 mmol) were placed in a 50 mL
Schlenk tube. Into the Schlenk tube, 1,4-dioxane (30 mL) was
added by a syringe. After the reaction in a refluxing solution for
28.5 h, yellow precipitate deposited. The precipitate was sepa-
rated, washed with 1,4-dioxane and then hexane, and dried
under vacuum to give 3c as yellow powder in 19% yield (49.5 mg,
0.0363 mmol). This compound was characterized by NMR spec-
troscopy. 1H NMR (300 MHz, CD2Cl2) δ 2.74 (br, 8H, DPPE),
3.65 (s, 12H, ortho-Me), 7.02-7.25 (m, 46H, aromatic protons).
31P{1H} NMR (122 MHz, CD2Cl2) δ 44.99 (s).
(0.0080 mmol, 88%) were observed in 96% conversion of 2d. 1d:
2
1H NMR (300 MHz, DMSO-d6, 30 °C) δ 1.16 (vt, JH-P
=
=
4JH-P = 2.1 Hz, 18H, mutually trans-PMe3), 1.33 (d, 2JH-P
10.2 Hz, 9H, PMe3), 1.36 (d, 2JH-P = 6.3 Hz, 9H, PMe3), 2.28 (s,
Ru(SC6H3Me2-2,6-K1S)2(PMe3)3 (2d). Complex 7d (14.6 mg,
0.0307 mmol) was treated with potassium 2,6-dimethylbenze-
nethiolate (17.8 mg, 0.101 mmol) in DME at 50 °C for 3 days.
After removal of all volatile matters, the resulting solid was
extracted with C6D6 and 1,4-dioxane was added as an internal
standard. Complex 2d was obtained in 17% yield as burgundy
crystals with concomitant formation of 1d (69%) and 7d (9%).
1H NMR (300 MHz, C6D6) δ 1.13 (m, 27H, PMe3), 2.55 (s, 12H,
C6H3Me2), 6.97 (t, 3JH-H = 7.2 Hz, 2H, para-C6H3Me2), 7.08
3H, SC6H3Me-6), 2.39 (tt, JH-P = 9.0, JH-P = 4.5 Hz, 2H,
SC6H3(CH2-2)), 6.76 (d, 3JH-H = 7.5 Hz, 1H, SC6H3), 6.89 (t,
3
3
3JH-H = 7.5 Hz, 1H, SC6H3), 7.01 (d, JH-H = 7.5 Hz, 1H,
3
SC6H3). 31P{1H} NMR (122 MHz, DMSO-d6, 30 °C) δ -15.5
(td, 2JP-P = 31, 2JP-P = 20 Hz, 1P, PMe3 trans to CH2), -6.58
=
(t, 2JP-P = 31 Hz, 2P, mutually trans-PMe3), 1.95 (td, 2JP-P
2
1
31, JP-P = 20 Hz, 1P, PMe3 trans to S). 2d: H NMR (300
MHz, DMSO-d6, 30 °C) δ 1.48 (br s, 18H, PMe3), 2.17 (s, 12H,
ortho-Me), 6.66 (t, 3JH-H = 7.5 Hz, 2H, para-C6H3Me2), 6.78
(d, 3JH-H = 7.5 Hz, 4H, meta-C6H3Me2). 31P{1H} NMR (162
MHz, DMSO-d6, 30 °C) 20.37 (s). 3d: 1H NMR (300 MHz,
DMSO-d6, 30 °C) δ 1.5 (overlapped with signal due to PMe3
resonances in 1d and 2d, 24H, PMe3 and SC6H3Me2), 1.6 (br s,
18H, PMe3), 2.22 (s, 6H, SC6H3Me2), 6.75-6.90 (br., over-
lapped with signal due to aromatic H in 2d, C6H3Me2). 31P{1H}
NMR (162 MHz, DMSO-d6, 30 °C) δ -9.45 (t, 2JP-P = 32 Hz,
3
(d, JH-H = 7.2 Hz, 4H, meta-C6H3Me2). 13C NMR (100.5
MHz, C6D6) δ 21.6-21.9 (m, PMe3), 24.4 (s, 1JC-H = 125 Hz,
1
C6H3Me2), 123.4 (s, JC-H = 158 Hz, C6H3Me2), 127.2 (s,
1JC-H = 151 Hz, C6H3Me2), 141.7 (s, C6H3Me2), 147.7 (s,
C6H3Me2). 31P{1H} NMR (122 MHz, C6D6, 20 °C) δ 16.6 (s).
Anal. Calcd for C25H45P3RuS2: C, 49.73; H, 7.51; S, 10.62%.
Found: C, 49.66; H, 8.01; S, 10.69%.
2
Protonolysis of 2d with HCl Gas. Complex 2d (4.6 mg, 0.0076
mmol) was placed in a NMR tube into which a dichloro-
methane-d2 solution (0.6 mL) was introduced. Triphenylmethane
(3.3 mg, 0.014 mmol) was added into the solution. Right after
introduction of excess dry HCl gas into the solution at room
temperature, the red solution turned yellow. NMR measurement
of the solution indicated formation of 2,6-dimethylbenzenethiol
(0.0155 mmol) in 205% yield. The other products could not be
characterized.
2P, mutually trans PMe3), 16.63 (t, JP-P = 32 Hz, 2P, PMe3
trans to S).
Treatment of 2d with PMe3 in Chloroform-d1. Complex 2d (5.2
mg, 0.0086 mmol) and a flame-sealed ampule containing P-
(OPh)3 in C6D6 as a standard were placed in an NMR tube into
which CDCl3 (0.6 mL) was introduced by vacuum distillation.
Triphenylmethane (3.3 mg, 0.014 mmol) was added into the
solution as an internal standard. Then, PMe3 (2.4 μL, 0.023
mmol) was added by a hypodermic syringe. The reaction was
monitored at 30 °C by NMR. After 1.5 h, 1d (0.0041 mmol,
48%) and 3d (0.00086 mmol, 10%) were observed in 99%
Treatment of 2d with PMe3 in Benzene-d6. Complex 2d (9.9 mg,
0.015 mmol) was placed in a NMR tube into which C6D6 (0.6 mL)
was introduced by vacuum transfer. 1,4-Dioxane (1.6 μL, 0.19 mmol)
1
conversion of 2d. 1d: H NMR (300 MHz, CDCl3, 23 °C) δ

Article
Organometallics, Vol. 29, No. 14, 2010 3157
2
2
1.21 (vt, 2JH-P = 4JH-P = 2.7 Hz, 18H, mutually trans-PMe3),
1.32 (d, 2JH-P = 6.6 Hz, 9H, PMe3), 1.40 (d, 2JH-P = 5.1 Hz,
(dt, JP-P = 86, JP-P = 39 Hz, 1P, P(OMe)3 trans to CH2),
156.8 (dt, 2JP-P = 86, 2JP-P = 43 Hz, 1P, P(OMe)3 trans to S).
Treatment of 2d with PMe2Ph. Complex 2d (7.0 mg, 0.012
mmol) was placed in an NMR tube into which C6D6 (0.6 mL)
was introduced by vacuum distillation. Then PMe2Ph (1.6 μL,
0.011 mmol) was added into the NMR tube by a hypodermic
syringe. The reaction system was monitored at 30 °C for 16.5 h
by NMR, then tripheylmethane (4.4 mg, 0.018 mmol) was added
to the reaction mixture as an internal standard. The conversion
of 2d was 99%, and unidentified products were formed in which
a 4:6 mixture of (OC-6-34)-Ru[SC6H3(CH2-2)(Me-6)-κ2S,C]-
(PMe3)3(PMe2Ph) (OC-6-34)-1g and (OC-6-24)-1g was pro-
duced in 31% yield with concomitant formation of 2,6-dim-
3
9H, PMe3), 2.37 (s. 3H, SC6H3Me), 2.47 (tt, JH-P = 12.6,
3JH-P = 4.5 Hz, 2H, SC6H3CH2), 6.89 (br. t, 3JH-H = 7 Hz, 1H,
SC6H3), 7.03 (br d, 3JH-H = 7 Hz, 2H, SC6H3). 31P{1H} NMR
(122 MHz, CDCl3, 24 °C) δ -16.26 (td, 2JP-P = 31, 2JP-P = 18
2
Hz, 1P, PMe3, trans to CH2), -7.72 (t, JP-P = 31 Hz, 2P,
mutually trans-PMe3), 1.53 (td, 2JP-P = 31, 2JP-P = 18 Hz, 1P,
PMe3 trans to S). 2d: 1H NMR (300 MHz, CDCl3, 23 °C) δ 1.51
(m, 27H, PMe3), 2.22 (s, 12H, SC6H3Me2), 6.71 (t, JH-H =
3
7 Hz, 1H, SC6H3Me2), 6.98 (d, 2JH-H = 7 Hz, 2H, SC6H3Me2).
1
31P{1H} NMR (122 MHz, CDCl3, 24 °C) δ 17.69 (s). 3d: H
NMR (300 MHz, CDCl3, 30 °C) δ 1.46 (br.m, 18H, PMe3), 1.52
1
2
4
ethylbenzenethiol in 36% yield. (OC-6-34)-1g: H (300 MHz,
C6D6, 19 °C) δ 0.98-1.12 (m, overlapped, PMe3 and PMe2Ph),
(s, 6H, ortho-Me), 1.59 (vt, JH-P = JH-P = 3.3 Hz, 18H,
PMe3), 2.35 (overlapped with ortho-Me groups in free 2,6-
dimethylbenzenethiol, ortho-Me), 6.57 (t, JH-H = 7 Hz, 1H,
3
3
3
2.75 (tt, JH-P = 13.5, JH-P = 4.5 Hz, 2H, SC6H3CH2), 2.9
(overlapped with ortho Me in (OC-6-24)-1g, SC6H3Me), 6.9-
7.25 (overlapped with other aromatic protons, SC6H3 and
PMe2Ph). 7.3-7.4 (overlapped with other aromatic protons,
3
para-C6H3Me2), 6.68 (d, JH-H = 7 Hz, 1H, para-C6H3Me2),
6.8-7.0 overlapped with aromatic protons. 31P{1H} NMR (122
MHz, CDCl3, 24 °C) δ -9.77 (t, 2JP-P = 33 Hz, 2P, mutually
trans PMe3), 12.08 (t, 2JH-H = 33 Hz, 2P, PMe3 trans to S).
Treatment of 2d with PMe3 in Dichloromethane-d2. Complex
2d (5.1 mg, 0.0084 mmol) was placed in an NMR tube into which
CD2Cl2 (0.6 mL) was introduced by vacuum distillation. Tri-
phenylmethane (2.9 mg, 0.012 mmol) was added as an internal
standard and then PMe3 (2.3 μL, 0.022 mmol) was added by a
hypodermic syringe. The reaction was monitored at 30 °C by
NMR. After 10 min, 1d (0.0013 mmol, 15%) and 3d (0.0058
PMe2Ph). 31P{1H} NMR (122 MHz, C6D6) δ -16.7 (td, 2JP-P
28, 2JP-P = 19 Hz, 1P, PMe2Ph trans to CH2), -8.32 (t, 2JP-P
=
=
28 Hz, 2P, mutually trans PMe3), 0.16 (td, 2JP-P = 28, 19 Hz, 1P,
PMe3 trans to S). (OC-6-24)-1g: 1H (300 MHz, C6D6, 19 °C) δ
0.98-1.12 (m, overlapped, PMe3 and PMe2Ph), 2.9 (overlapped
3
with ortho Me in (OC-6-34)-1g, SC6H3Me), 3.11 (tt, JH-P
=
3
13.5, JH-P =4.5 Hz, 2H, SC6H3CH2), 6.9-7.25 (overlapped
with other aromatic protons, SC6H3 and PMe2Ph). 7.3-7.4
(overlapped with other aromatic protons, PMe2Ph). 31P{1H}
NMR (122 MHz, C6D6) δ -17.60 (td, 2JP-P = 28, 2JP-P = 19
1
mmol, 69%) were observed in 90% conversion of 2d. 1d: H
=
NMR (300 MHz, CD2Cl2, 19 °C) δ 1.19 (vt, 2JH-P = 4JH-P
2.7 Hz, 18H, mutually trans-PMe3), 1.34 (d, JH-P = 7.5 Hz,
2
2
Hz, 1P, PMe3 trans to CH2), -9.62 (t, JP-P = 28 Hz, 2P,
mutually trans PMe3), 9.35 (td, 2JP-P = 28, 19 Hz, 1P, PMe2Ph
trans to S).
2
9H, PMe3), 1.39 (d, JH-P = 5.7 Hz, 9H, PMe3), 2.28 (s. 3H,
SC6H3Me), 2.45-2.50 (m, 2H, SC6H3CH2), 6.9-7.0 (m, over-
lapped with other aromatic signals, SC6H3). 31P{1H} NMR (122
MHz, CD2Cl2, 19 °C) δ -16.3 (td, 2JP-P = 31, 2JP-P = 18 Hz,
1P, PMe3, trans to CH2), -7.9 (t, 2JP-P = 31 Hz, 2P, mutually
Treatment of 2d with CO. Complex 3h (17.6 mg, 0.0259 mmol)
was placed in a Schlenk tube into which benzene (5 mL) was
added. After cooling of the reaction mixture with liquid nitro-
gen, the reaction system was evacuated. Carbon monoxide
(0.1 MPa) was then introduced to the Schlenk tube. Right after
exposure of 2d to CO, the red solution turned to yellow. After
10 min, all volatile matters were removed under reduced pres-
sure to give yellow powder, which was repeatedly washed with
hexane. After drying of the resulting yellow powder under
reduced pressure, cis,cis,cis-Ru(SC6H3Me2-2,6)2(PMe3)2(CO)2
(cis,cis,cis-3h) was obtained in 93% yield (12.5 mg, 0.024 mmol).
At 50 °C in benzene, 3h constitutes an equilibrium mixture
between cis,cis,cis-3h and trans,trans,trans-3h (Keq = [trans,
2
2
trans-PMe3), 1.5 (td, JP-P=31, JP-P = 18 Hz, 1P, PMe3
trans to S). 3d: 1H NMR (300 MHz, CD2Cl2, 30 °C) δ 1.45 (m,
2
4
18H, PMe3), 1.52 (vt, JH-P = JH-P = 3.3 Hz, 18H, PMe3),
2.56 (s, 12H, SC6H3Me2), 7.14-7.23 (m, 6H, SC6H3Me2). 31P-
{1H} (122 MHz, CD2Cl2, 30 °C) δ -10.01 (t, 2JP-P = 33 Hz, 2P,
mutually trans PMe3), 11.62 (t, 2JH-H = 33 Hz, 2P, PMe3 trans
to S).
Treatment of 2d with H2O. Complex 2d (9.7 mmol, 0.014
mmol) was placed in a NMR tube into which C6D6 (600 μL) was
introduced by vacuum transfer. 1,4-Dioxane (1.4 μL, 0.16
mmol) was added as an internal standard. Degassed deionized
water (5.0 μL, 0.28 mmol) was added by a hypodermic syringe.
After 3 days at room temperature, cis,mer-Ru(SC6H3Me2-2,6)2-
1
trans,trans-3h][cis,cis,cis-3h] = 9.9 at 50 °C). cis,cis,cis-3h: H
NMR (300 MHz, C6D6) δ 0.95 (d, 2JH-P = 9 Hz, 9H, PMe3),
1.31 (d, JH-P = 9 Hz, 9H, PMe3), 2.54 (s, 6H, ortho-
2
1
(PMe3)3(OH2) (3e) was produced in 62% yield. 3e: H NMR
(300 MHz, C6D6) δ 1.12-1.15 (m, 9H, PMe3 trans to S), 1.20 (vt,
=
SC6H3Me2), 2.90 (s, 6H, ortho-SC6H3Me2), 6.96 (t, 3JH-H = 7 Hz,
1H, para-SC6H3Me2), 7.08 (t, JH-H = 7 Hz, 1H, para-
3
3
SC6H3Me2), 7.12 (d, JH-H = 7 Hz, 2H, meta-SC6H3Me2),
2JH-P
4JH-P = 2.7 Hz, 18H, mutually trans-PMe3),
2.45-2.50 (br s, 12H, SC6H3Me2), 6.95 (t, 3JH-H = 7 Hz, 2H,
SC6H3Me2), 7.03 (br d, JH-H = 7 Hz, 4H, SC6H3Me2), 11.5
7.26 (d, JH-H =7 Hz, 2H, meta-SC6H3Me2). 31P{1H} (122
3
MHz, C6D6) δ -16.09 (d, 2JP-P = 35 Hz, 1P, PMe3), -11.46 (d,
2JP-P = 35 Hz, 1P, PMe3). IR (KBr, cm-1) 3041(w), 2963(w),
2913(w), 2036(s). 1973(vs), 1458(w), 1424(w), 1365(w), 1312(w),
1291(w), 1160(w), 1054(w), 960(m), 946(m), 849(w), 763(m),
740(w), 719(w), 585(w), 561(m). Anal. Calcd for C24H36O2-
P2RuS2: C, 49.39; H, 6.22%. Found: C, 49.38; H, 6.75%.
trans,trans,trans-3h: 1H NMR (300 MHz, C6D6) δ 1.08 (vt,
3
(br, 2H, OH2). 31P{1H} NMR (122 MHz, C6D6) δ -3.58 (d,
=
2JP-P = 36 Hz, 2P, mutually trans PMe2), 39.68 (t, JP-P
36 Hz, 1P, PMe3 trans to S).
2
Treatment of 2d with P(OMe)3. Complex 2d (5.6 mg, 0.0093
mmol) was placed in an NMR tube into which triphenylmethane
(5.5 mg, 0.0225 mmol) was added as an internal standard.
Trimethylphosphite (1.2 μL, 0.01 mmol) was added into the
solution. After 10 min at room temperature, 2d was completely
converted into cis,trans,cis-Ru[SC6H3(CH2-2)(Me-6)-κ2S,C]-
(PMe3)2[P(OMe)3]2 (1f) in 100% yield. Complex 1f was char-
2JH-P = JH-P = 3.7 Hz, 18H, mutually trans PMe3), 2.89 (s,
4
12H, SC6H3Me2), 6.96 (t, 3JH-H = 7 Hz, 2H, para-SC6H3Me2),
7.07 (d, JH-H = 7 Hz, 4H, meta-SC6H3Me2). 31P{1H} NMR
3
(122 MHz, C6D6) δ -14.81 (s).
1
acterized by spectroscopic methods. 1f: H NMR (300 MHz,
C6D6) δ 1.47 (vt, 2JH-P = 4JH-P = 4 Hz, 18H, mutually trans
PMe3), 1.86 (s, 3H, C6H3Me), 2.5 (br, 2H, C6H3CH2), 3.27 (d,
Treatment of 2a with PMe3. Complex 2a (324.5 mg, 0.4030
mmol) was dissolved in a THF solution (16 mL) into which
PMe3 (120 μL, 1.16 mmol) was added by use of a hypodermic
syringe. The reaction mixture was warmed at 50 °C for 2 days.
Then, all volatile matters were removed under reduced pressure
and the resulting solid was dissolved with acetone. Hexane was
added into the acetone solution to deposit unreacted 2a. The
3
3JH-P = 11 Hz, 9H, P(OMe)3), 3.33 (d, JH-P = 10 Hz, 9H,
P(OMe)3), 7.0-7.2 (partly overlapped with undeuterated ben-
zene in C6D6, C6H3). 31P{1H} NMR (122 MHz, C6D6) δ 3.5 (dd,
2
2JP-P = 43, JP-P = 39 Hz, 2P, mutually trans-PMe3), 100.7

3158 Organometallics, Vol. 29, No. 14, 2010
Hirano et al.
Table 1. Crystallographic Data for Ru(SC6H3Me2-2,6-K1S)2(TRIPHOS-K3P,P0,P00) (2a), Ru(SC6H3Me2-2,6-κ1S)2(PMe3)3 (2d), and
Ru(SC6H3Me2-2,6-κ1S)2(η4-1,5-COD) (4a)
2a
2d
4a 0.5MePh
3
chemical formula
formula weight
cryst size (mm)
cryst syst
C
50H51P3RuS2
C25H45P3RuS2
603.74
0.30 ꢀ 0.25 ꢀ 0.10
orthorhombic
P212121
16.183(3)
18.546(2)
10.144(4)
C45.5H49P3Ru
789.88
0.30 ꢀ 0.20 ꢀ 0.10
orthorhombic
Pbca
17.822(12)
17.854(13)
25.904(9)
910.06
0.20 ꢀ 0.20 ꢀ 0.10
monoclinic
P21/n
13.2(2)
24.1(3)
14.8(2)
107(1)
8242(6)
4
270.2
Mo KR
0.71069
11081
space group
˚
a (A)
˚
b (A)
˚
c (A)
β (deg)
3
V (A )
˚
3044.7(13)
4
200.0
Mo KR
0.71069
4387
8242(9)
8
293.1
Mo KR
0.71069
9448
Z
measurement temp (K)
radiation type
radiation wavelength (A)
total no. of reflns
no. of reflns gt
˚
7487
3228
4395
reflns threshold expression
Ra
Rw
I > 3.0 σ(I)
0.047
0.072
F2 > 2.0 σ(F2)
0.0420
0.0962
0.713
F2 > 2.0 σ(F2)
0.0555
0.2060
1.001
b
goodness of fit
1.118
P
P
P
P
a R = ||Fo| - |Fc||/ |Fo|. b Rw = [ w(|Fo| - |Fc|)2/ w|Fo|2]1/2
.
precipitate was filtered off, and the resulting solution was
evaporated to dryness. The solid was recrystallized from cold
acetone to give yellow crystals of 1a in 51% yield (154.7 mg,
0.2055 mmol). These crystals were found to be an 80/20 mixture
of (OC-6-34)-1a and (OC-6-25)-1a. (OC-6-34)-1a: 1H NMR
(300 MHz, C6D6) δ 0.46 (d, J = 7.2 Hz, 9H, PMe3), 1.4-2.6
(overlapped, CH2 in TRIPHOS), 2.5-2.6 (m, 1H, ortho-CH2),
2.88 (m, 1H, ortho-CH2), 3.15 (s, 3H, ortho-Me), 6.5-8.1 (m,
28H, aromatic protons). 31P{1H} NMR (122 MHz, C6D6)
δ -10.0 (ddd, J = 349, 27, 23 Hz, 1P), 39.9 (ddd, J = 349, 19,
12 Hz, 1P), 47.1 (dd, J = 23, 12 Hz, 1P) and 90.2 (dd, J = 27, 19
Hz). (OC-6-25)-1a: 1H NMR (300 MHz, C6D6) δ 1.37 (d, J =
6.3 Hz, 9H, PMe3), 1.4-2.6 (overlapped, CH2 in TRIPHOS),
2.60 (s, 3H, ortho-Me), the methylene protons in the ortho-CH2
were obscured. 6.5-8.1 (m, 28H, aromatic protons). 31P{1H}
NMR (122 MHz, C6D6) δ -16.6 (ddd, J = 360, 24, 22 Hz, 1P),
50.9 (ddd, J = 22, 10, 5 Hz, 1P), 73.6 (m, 1P) and 89.9 (ddd, J =
360, 30, 10 Hz, 1P). The 13C{1H} NMR spectrum was measured
as a mixture of isomers: 13C{1H} NMR (100.5 MHz, C6D6) δ
14.3 (s), 16.2 (d, 1JC-P = 24 Hz, PMe3), 18.9 (d, 1JC-P = 24 Hz,
PMe3), 22.1 (s), 23.0 (s), 23.4 (s), 24.8 (d, JC-P = 25 Hz,
TRIPHOS), 25.1 (d, JC-P = 25 Hz, TRIPHOS), 27.0 (d,
δ 16.9 (s) at 263 K, δ 17.0 (s) at 253 K, δ 17.3 (s) at 243 K, δ 17.5
(s) at 233 K, δ 17.6 (s) at 223 K, δ 17.8 (s) at 213 K, δ 18.0 (s) at
203 K, δ 17.6 (s) at 223 K, δ 17.4 (s) at 233 K, δ 17.3 (s) at 243 K,
δ 17.1 (s) at 253 K, δ 16.6 (s) at 283 K. The ortho Me resonance in
the 1H NMR spectra also slightly shifted to the lower magnetic
field by cooling as follows: δ 2.48 (s, 12H) at 283 K, δ 2.49 (s,
12H) at 273 K, δ 2.50 (s, 12H) at 263 K, δ 2.52 (s, 12H) at 253 K,
δ 2.53 (s, 12H) at 243 K, δ 2.54 (s, 12H) at 233 K, δ 2.56 (s, 12H)
at 223 K, δ 2.58 (s, 12H) at 213 K, δ 2.59 (s, 12H) at 203 K, δ 2.56
(s, 12H) at 223 K, δ 2.53 (s, 12H) at 233 K, δ 2.53 (s, 12H) at 243
K, δ 2.52 (s, 12H) at 253 K, δ 2.51 (s, 12H) at 283 K. No apparent
change in the other signals in the 1H NMR spectra was observed.
Treatment of a Mixture of (OC-6-34)-1a and (OC-6-25)-1a
with 2,6-Dimethylbenzenethiol. A mixture of (OC-6-34)-1a and
(OC-6-25)-1a (12.8 mg, 0.0151 mmol) was placed in an NMR
tube into which benzene-d6 (ca. 0.6 mL) was transferred by
vacuum distillation. 2,6-Dimethylbenzenethiol (4.0 μL, 0.030
mmol) was added into the solution by a hypodermic syringe.
The reaction mixture was heated at 70 °C, and the reaction was
monitored by the NMR. After 3 days, complex 2a was produced
in 83% yield based on the internal standard.
Treatment of a Mixture of (OC-6-34)-1a and (OC-6-25)-1a
with Hydrogen. A mixture of (OC-6-34)-1a and (OC-6-25)-1a
(14.1 mg, 0.0166 mmol) was placed in an NMR tube. After
evacuation of the NMR tube, benzene-d6 (ca. 0.6 mL) was
transferred by vacuum distillation. Diphenylmethane (4.0 μL,
0.024 mmol) was added into the solution as an internal standard.
After evacuation of the system, hydrogen gas (0.1 MPa) was
introduced into the solution and the reaction system was heated
at 50 °C for 1 day. Both 1H and 31P{1H} NMR spectra suggested
exclusive formation of (OC-6-34)-8a (60% yield, 0.010 mmol).
1H NMR (300 MHz, C6D6) δ -6.81 (dddd, 2JH-P = 95.8, 34.8,
19.2, 14.4 Hz, 1H, Ru-H), 0.51 (d, 2JH-P = 7.2 Hz, 9H, PMe3),
3.03 (s, 6H, C6H3Me2), 6.8-7.2 (overlapped with diphenyl-
methane resonances), 7.56 (t, J = 7.2 Hz, 4H, TRIPHOS),
7.95 (q, J = 7.2 Hz, 4H, TRIPHOS), 8.34 (t, J = 8.4 Hz, 2H,
TRIPHOS). 31P{1H} NMR (122 MHz, C6D6) δ -7.87 (dt, J =
283, 27 Hz, 1P, PMe3), 35.3 (m, 1P, PPh2), 64.2 (ddd, J = 283,
17, 5 Hz, 1P, PPh2), 105.7 (dd, J = 29, 19 Hz, 1P, PPh). Anal.
Calcd for C45H52P4RuS: C, 63.59; H, 6.17. Found: C, 64.21; H,
6.55.
JC-P = 23 Hz, TRIPHOS), 27.2 (d, JC-P = 23 Hz, TRIPHOS),
28.6 (d, JC-P = 25 Hz, TRIPHOS), 28.8 (d, JC-P = 25 Hz,
TRIPHOS), 31.7 (d, JC-P = 25 Hz, TRIPHOS), 31.8 (d, JC-P
25 Hz, TRIPHOS), 31.9 (s), 124.0 (s), 124.7 (s), 126.7 (d, JC-P
=
=
8 Hz, TRIPHOS), 127.0-129.5 (obscured by overlapping with
the C6D6 resonance), 130.2 (d, JC-P = 9 Hz, TRIPHOS), 130.6
(d, JC-P = 10 Hz, TRIPHOS), 131.1 (d, JC-P = 6 Hz, TRIPHOS),
131.4 (d, JC-P = 7 Hz, TRIPHOS), 131.9 (s), 132.0 (s), 132.2 (d,
JC-P = 10 Hz, TRIPHOS), 132.8 (d, JC-P = 10 Hz, TRIPHOS),
134.6 (d, JC-P = 10 Hz, TRIPHOS), 135.6 (s), 136.4 (s), 137.4 (d,
JC-P = 34 Hz, TRIPHOS), 139.1 (d, JC-P = 33 Hz, TRIPHOS),
140.3 (d, JC-P = 29 Hz, TRIPHOS), 141.6 (d, JC-P = 23 Hz,
TRIPHOS), 144.9 (d, JC-P = 22 Hz, TRIPHOS), 151.6 (d,
JC-P = 8 Hz, TRIPHOS), 155.7 (d, JC-P = 13 Hz, TRIPHOS).
The elemental analysis was measuredas a mixtureof regioisomers.
Anal. Calcd for C47H56P4RuS: C, 64.30; H, 6.43. Found: C, 64.67;
H, 6.78.
Variable Temperature NMR Spectra of 2d. Complex 2d
(4.6 mg, 0.010 mmol) was placed in a NMR tube into which
toluene-d8 (0.6 mL) was introduced by vacuum distillation. 1H
and 31P{1H} NMR spectra were measured in the range 283-203
K. The 31P{1H} NMR data slightly shifted to the lower magnetic
field by cooling as follows: δ 16.6 (s) at 283 K, δ 16.8 (s) at 273 K,
Treatment of 1d with 2,6-Dimethylbenzenethiol. Complex 1d
(197.7 mg, 0.3643 mmol) was placed in a 50 mL Schlenk tube
into which 9 mL of acetone was added. 2,6-Dimethylbenzen-
ethiol (242.0 μL, 1.817 mmol) was added to the solution by a

Article
Organometallics, Vol. 29, No. 14, 2010 3159
hypodermic syringe, and the reaction mixture was stirred for 15 h
at room temperature. All volatile matters were removed off under
vacuum, and resulting red solid was recrystallized from toluene to
give red crystals of 2d in 32% yield (70.5 mg, 0.104 mmol).
Kinetic Study for the Reaction of 2d with PMe3. A typical
example is as follows. A benzene solution of 2d (5.00 mL, 9.44 ꢀ
10-4 M, 0.00472 mmol) was added into a Schlenk type quartz
UV cell by a measuring pipet. Then, PMe3 (4.3 μL, 0.042 mmol)
was added into the cell by a hypodermic syringe. The time-
course of the reaction was monitored by the absorption maxi-
mum in benzene at 518 nm. During measurement of the
reaction, the cell temperature was set up at 30.0 °C by a
thermostatted UV cell holder and the deviation of the temp-
erature was less than (0.5 °C.
Effect of Added Potassium 2,6-Dimethylbenzenethiolate on the
Conversion Rate of 2d to 1d. A THF solution of 2d (3.00 mL,
1.57 ꢀ 10-4 M, 0.00471 mmol) and a THF solution of potassium
2,6-dimethylbenzenethiol (2.00 mL, 4.80 ꢀ 10-2 M, 0.0960
mmol) were added into a Schlenk type quartz UV cell by a
measuring pipet. Then, PMe3 (4.3 μL, 0.042 mmol) was added
into the cell by a hypodermic syringe. The time-course of the
reaction was monitored by the absorption maximum 30 ( 0.5 °C
in THF at 511 nm.
rates were 16.0 deg min-1. Three standard reflections were
monitored in every 150 reflections. Intensities were corrected for
Lorentz and polarization effects. The crystallographic data and
details associated with data collection for 2a, 2d, and 4a are given
in Table 1. The data were processed using a teXsan software for 2a
and CrystalStructure package software for 2d and 4a.42 All non-
hydrogen atoms were found by using the results of the Direct
methods (DIRDIF-94 for 2a, SHELXL-9743 for 4a) and PATTY
(DIRDIF-99) (2d). Anabsorption correction was applied with the
program PSI SCAN method. All non-hydrogen atoms were found
on difference maps. All hydrogen atoms were located in the cal-
culated positions. The crystal of 4a contained 0.5 MePh mole-
cule, which was solved isotropically. Crystallographic thermal
parameters and bond distances and angles have been deposited as
Supporting Information.
Acknowledgment. This was financially supported by
the Ministry of Education, Culture, Sports, Science, and
Technology, Japan. We thank S. Kiyota for elemental
analyses.
Supporting Information Available: Tables of atomic coordi-
nates and equivalent anisotropic displacement parameters and
bond distances and angles for 2a, 2d, and 4a, typical first-order
rate plots for 2a and 2d, and first-order rate constants for
conversion of 2a and 2d. This material is available free of charge
via the Internet at http://pubs.acs.org.
Effect of Added Galvinoxyl on the Conversion Rate of 2d to 1d.
A benzene solution of 2d and galvinoxyl (5.00 mL, 2d: 9.4 ꢀ 10-4
M, 0.0047 mmol; galvinoxyl: 3.4 ꢀ 10-4 M, 0.0031 mmol) were
added into a Schlenk type quartz UV cell by a measuring pipet.
Then, PMe3 (4.3 μL, 0.042 mmol) was added into the cell by a
hypodermic syringe. The time-course of the reaction was moni-
tored at 30 ( 0.5 °C by the absorption maximum in benzene at
518 nm.
(42) Rigaku Americas and Rigaku Corporation. CrystalStructure
(Version 3.8). Single Crystal Structure Analysis Software; Rigaku Amer-
icas: 9009 TX, USA 77381-5209 ; Rigaku: Tokyo 196-8666, Japan, 2007.
X-ray Crystallography of 2a, 2d, and 3a. The crystallographic
data were measured on a Rigaku RASA-7R four-circle diffracto-
€
€
(43) Sheldrick, G. M. SHELXL-97; University of Gottingen, Gottingen,
Germany, 1997.
˚
(44) Abbreviations used in this text: COD, cyclooctadiene (C8H12);
COT, cyclooctatriene (C8H10); DMF, dimethylformamide (Me2NCHO);
DMSO, dimethylsulfoxide (Me2SO); DPPE, 1,2-bis(diphenylphosphino)-
ethane (Ph2PC2H4PPh2); TDPM, tris(diphenylphosphino)methane
[HC(CH2PPh2)3]; TDPME, tris(diphenylphsphinomethyl)ethane [MeC-
(CH2PPh2)3]; TRIPHOS, bis[2-(diphenylphosphino)ethyl]phenyl-
phosphine (Ph2C2H4PPhC2H4Ph).
meter using Mo KR (λ = 0.71069 A) radiation with a graphite
crystal monochromator. A single crystal was selected by use of a
polarized microscope and mounted onto a glass capillary with
Paraton N oil. The unit cell dimensions were obtained by a least-
squares fit of 20 centered reflections. Intensity data were collected
using the ω-2θ technique to a maximum 2θ of 55.0°. The scan