Formation of divalent ruthenacycles via oxidative cyclization of 1,3,5-cyclooctatriene with maleic anhydride or maleimides: An intermediate for the transition metal-mediated [6 + 2] cycloaddition of 1,3,5-trienes and alkenes

Article abstract of DOI:10.1021/om060242t

Reactions of a zerovalent ruthenium complex, Ru(η⁴-cod) (η⁶-cot) (3; cod = 1,5-cyclooctadiene, cot = 1,3,5- cyclooctatriene), with maleic anhydride or maleimides under mild reaction conditions afforded a series of novel divalent ruthenacycles 4 with an η⁵-cyclooctadienyl moiety via oxidative cyclization between the carbon-carbon double bonds of cot and the electron-deficient alkene. The solid-state structure clearly showed a newly constructed ruthenacycle skeleton, which was formed in a trans manner. Complex 4 was further reacted with H ₂ and HCl to give hydrogenated and protonated succinimides with a C₈-ring, respectively. When 4 was heated in toluene, a [6 + 2] cycloadduct of cot and a maleimide was obtained via reductive elimination, which shows that a ruthenium-mediated stepwise [6 + 2] cycloaddition was achieved. The addition of PPh₃ to complex 4d promoted the reductive elimination, while bidentate phosphines such as 1,2-bis(diphenylphosphino)ethane did not give the cycloadduct and stable ruthenacycles 11 were formed instead. Reactions of 4 with CO gave novel tricarbonyl ruthenacycles 12 along with dissociation of the cod ligand, where neither reductive elimination nor CO insertion took place. The results of a theoretical study were consistent with the idea that the energy barriers for reductive elimination from ruthenacycles bearing cod or monophosphine ligands were lower than those from a ruthenacycle bearing a diphosphine ligand. The formation of 12 was found to be more energetically favorable than reductive elimination.

Full text of DOI:10.1021/om060242t

2934
Organometallics 2006, 25, 2934-2942
Formation of Divalent Ruthenacycles via Oxidative Cyclization of
1,3,5-Cyclooctatriene with Maleic Anhydride or Maleimides: An
Intermediate for the Transition Metal-Mediated [6 + 2]
Cycloaddition of 1,3,5-Trienes and Alkenes
Yasuyuki Ura,* Taka-aki Utsumi, Hiroshi Tsujita, Kenji Wada, Teruyuki Kondo, and
Take-aki Mitsudo*
Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto UniVersity,
Nishikyo-ku, Kyoto 615-8510, Japan
ReceiVed March 16, 2006
Reactions of a zerovalent ruthenium complex, Ru(η4-cod)(η6-cot) (3; cod ) 1,5-cyclooctadiene, cot )
1,3,5-cyclooctatriene), with maleic anhydride or maleimides under mild reaction conditions afforded a
series of novel divalent ruthenacycles 4 with an η5-cyclooctadienyl moiety via oxidative cyclization between
the carbon-carbon double bonds of cot and the electron-deficient alkene. The solid-state structure clearly
showed a newly constructed ruthenacycle skeleton, which was formed in a trans manner. Complex 4
was further reacted with H2 and HCl to give hydrogenated and protonated succinimides with a C8-ring,
respectively. When 4 was heated in toluene, a [6 + 2] cycloadduct of cot and a maleimide was obtained
via reductive elimination, which shows that a ruthenium-mediated stepwise [6 + 2] cycloaddition was
achieved. The addition of PPh3 to complex 4d promoted the reductive elimination, while bidentate
phosphines such as 1,2-bis(diphenylphosphino)ethane did not give the cycloadduct and stable ruthenacycles
11 were formed instead. Reactions of 4 with CO gave novel tricarbonyl ruthenacycles 12 along with
dissociation of the cod ligand, where neither reductive elimination nor CO insertion took place. The
results of a theoretical study were consistent with the idea that the energy barriers for reductive elimination
from ruthenacycles bearing cod or monophosphine ligands were lower than those from a ruthenacycle
bearing a diphosphine ligand. The formation of 12 was found to be more energetically favorable than
reductive elimination.
Proposed mechanisms for metal-mediated or -catalyzed [6 +
2] cycloaddition are often discussed based on the results of [6
Introduction
Transition metal-mediated or -catalyzed cycloadditions are
versatile tools for the synthesis of a wide variety of cyclic
compounds through the simultaneous formation of two or more
carbon-carbon and/or carbon-heteroatom bonds.1 Since the
Fe-mediated [6 + 2] cycloaddition of 1,3,5-cycloheptatriene with
cyclobutenes or alkynes was reported by Pettit et al. (eq 1),2
several stoichiometric and catalytic [6 + 2] cycloadditions of
conjugated cyclic trienes with alkenes, dienes, and alkynes using
several transition metal complexes under either photoirradiated
or thermal conditions have been intensively investigated (eq
2).3-8 In some cases the reactions were applied to the synthesis
of natural products.4f,h,9 In contrast to the successful development
of catalytic reactions, little effort has been devoted to isolation
of the reaction intermediates and investigation of their reactivity.
(4) Cr-mediated or -catalyzed reactions: (a) Kreiter, C. G.; Michels, E.;
Kurz, H. J. Organomet. Chem. 1982, 232, 249. (b) Rigby, J. H.; Hensilwood,
J. A. J. Am. Chem. Soc. 1991, 113, 5122. (c) Fischler, I.; Grevels, F.-W.;
Leitich, J.; O¨ zkar, S. Chem. Ber. 1991, 124, 2857. (d) Rigby, J. H.; Short,
K. M.; Ateeq, H. S.; Henshilwood, J. A. J. Org. Chem. 1992, 57, 5290. (e)
Chaffee, K.; Sheridan, J. B.; Aistars, A. Organometallics 1992, 11, 18. (f)
Rigby, J. H.; Ateeq, H. S.; Charles, N. R.; Hensilwood, J. A.; Short, K.
M.; Sugathapala, P. M. Tetrahedron 1993, 49, 5495. (g) Rigby, J. H.;
Sandanayaka, V. P. Tetrahedron Lett. 1993, 34, 935. (h) Rigby, J. H. Acc.
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* To whom correspondence should be addressed. E-mail: yura@
scl.kyoto-u.ac.jp; mitsudo@scl.kyoto-u.ac.jp.
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10.1021/om060242t CCC: $33.50 © 2006 American Chemical Society
Publication on Web 05/13/2006

Formation of DiValent Ruthenacycles
Organometallics, Vol. 25, No. 12, 2006 2935
+ 4] cycloaddition,10,11 and, to the best of our knowledge, the
real intermediate species for [6 + 2] cycloaddition have not
yet been identified. Pettit et al. reported the formation of
ferracycle 1 (Chart 1), which was obtained by the reaction of
Fe(1,3,5-cycloheptatriene)(CO)3 with dimethyl maleate and
might be considered the intermediate species; however, the
subsequent ring-closing step did not proceed.2b Reactions of
transition metal complexes with a cyclic-1,3,5-triene and alkynes
tend to readily afford complexes such as 2 bearing the
corresponding [6 + 2] cycloadducts via reductive elimination,
and thus it is difficult to isolate intermediate metallacycles of
this type.
Chart 1
anhydride and maleimides, to give a series of stable divalent
ruthenacycles that were formed via oxidative cyclization of the
coordinated cot with the added alkenes. The reactivity of these
complexes was investigated further, and ring-closing reductive
elimination was found to give a [6 + 2] cycloadduct of cot and
a maleimide. Theoretical investigation of the reductive elimina-
tion step revealed that the energy barrier is highly influenced
by the steric and electronic factors of the spectator ligands.
Results and Discussion
Reaction of 3 with Maleic Anhydride or Maleimides:
Formation of Ruthenacycles 4 via Oxidative Cyclization. The
reaction of complex 3 with 1.0 equiv of maleic anhydride in
n-hexane at 40 °C for 2 h afforded yellow microcrystals, which
were isolated by filtration. NMR, IR, and mass spectroscopic
analysis of the obtained solids suggested the formation of the
1:1 adduct of complex 3 and maleic anhydride, presumably
divalent ruthenacycle 4a depicted in eq 3. Several maleimides
could also be used and gave ruthenacycles of this type, 4b-e,
in good to high yield.
In the course of our studies on the reactivity of alkenes on
low-valent ruthenium complexes,12 a versatile Ru(0) complex
Ru(η4-cod)(η6-cot) (3; cod ) 1,5-cyclooctadiene, cot ) 1,3,5-
cyclooctatriene), the reactivity and catalytic activity of which
have been intensively investigated by several groups,12-32 was
found to react with electron-deficient alkenes such as maleic
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2936 Organometallics, Vol. 25, No. 12, 2006
Ura et al.
p-Benzoquinone gave an insoluble material that could not be
characterized by usual analytical methods.12c Methyl acrylate,
N,N-dimethylacrylamide, and methyl vinyl ketone were also
used; however, almost no reaction proceeded, even at higher
temperature, and 3 remained unreacted, probably due to their
relatively poor electron-accepting abilities. On the other hand,
the reaction of 3 with terminal alkynes has been reported, where
[6 + 2] cycloaddition of cot and alkynes proceeded to give
zerovalent complexes with a resulting η4,η2-bicyclodecatriene
ligand.7b
Possible pathways for the formation of 4 are depicted in
Scheme 1. The coordination mode of the cot ligand in 3 initially
changes from 1-6-η6 to either 1-2:5-6-η4 or 1-4-η4, and then 5
occupies the vacant coordination site to give 6 or 6′. It is known
that cot is more labile than cod in 3 to afford Ru(η4-cod)(η4-
cot)(L) (L ) monodentate ligand), by the reaction of 3 with
either CO15b or phosphorus ligands.15d,17a Oxidative cyclization
between CdC of cot and 5 gives coordinatively unsaturated
16e ruthenacyclopentane intermediate 7 or 7′, and subsequent
recoordination of the dissociated CdC leads to ruthenacycles
4 with an η5-cyclooctadienyl moiety. Complexes 4 are rare
examples of isolated ruthenacycles formed via oxidative cy-
clization of carbon-carbon double bonds.33
Reactivity of Ruthenacycles 4: (a) Hydrogenation and
Protonolysis. To investigate the fundamental reactivity of the
ruthenacycles, hydrogenation and protonolysis of 4d were
performed (eq 4). When 4d was reacted with H2 at 1 atm,
N-phenylcyclooctylsuccinimide 8 was obtained in 56% isolated
yield. On the other hand, treatment with HCl in Et2O afforded
N-phenyl(3,5-cyclooctadien-1-yl)succinimide 9 in 62% yield
under mild reaction conditions. In this reaction, selective
protonolysis of the η5-cyclooctadienyl moiety occurred at the
2-position and no other isomers were observed at all.
Figure 1. ORTEP drawing of 4e. Thermal ellipsoids are shown at
the 50% probability level. Hydrogen atoms are omitted for clarity
except for those on C1, C6, C7, and C8. Selected bond distances
(Å): Ru1-C1 ) 2.228(5), Ru1-C2 ) 2.200(5), Ru1-C3 ) 2.250-
(5), Ru1-C4 ) 2.227(5), Ru1-C5 ) 2.224(5), Ru1-C8 ) 2.266-
(5), C1-C2 ) 1.381(8), C1-C6 ) 1.504(7), C2-C3 ) 1.440(8),
C3-C4 ) 1.400(8), C4-C5 ) 1.420(7), C6-C7 ) 1.524(7), C7-
C8 ) 1.547(7).
Single crystals of 4e were obtained by recrystallization from
CHCl3/pentane, and the molecular structure was determined by
X-ray crystallography (Figure 1). A new C-C bond was formed
between C6 and C7 in a trans manner. The bond distances of
C1-C6, C6-C7, and C7-C8 are in the range of C-C single
bonds (1.504(7), 1.524(7), and 1.547(7) Å, respectively). The
average Ru-C bond distance in the η5-cyclooctadienyl moiety
is 2.23 Å, which is slightly shorter than the Ru1-C8 bond
distance of 2.266(5) Å. The five-membered ring (Ru1-C1-
C6-C7-C8) clearly corresponds to a newly constructed ruth-
enacyclopentane skeleton.
In the 1H NMR spectra of 4, the methyne protons of the η5-
moiety were observed within a wide range, at 2.6-6.6 ppm,
while those of cod appeared within a rather narrow range, at
2.8-3.9 ppm. The signal for the R-hydrogen on the sp3 carbon
(corresponding to H on C8 in Figure 1) appeared as a doublet
at 4.2-4.4 ppm. The â-hydrogen signal (H on C7) also appeared
as a doublet, which was not split by the H on C6 (e.g., the
dihedral angle of H-C6-C7-H in 4e is ca. 80°). In the 13C
NMR spectra of 4, the coordinated carbons of the cycloocta-
dienyl moiety and cod appeared at a higher magnetic field, at
62-106 and 76-93 ppm, respectively. The sp3 R-carbon signal
(C8) had almost the same chemical shifts (29-35 ppm) as that
of free succinic anhydride or succinimides, while the sp3
â-carbon signal (C7) was shifted to a lower field by ca. 30 ppm.
Other electron-deficient alkenes were also examined in
addition to maleic anhydride and maleimides. The reaction
of 3 with dimethyl fumarate or dimethyl maleate afforded
the zerovalent complex Ru(η6-cot)(η2-dimethyl fumarate)2.12b
(b) Ruthenium-Mediated Stepwise [6 + 2] Cycloaddition
of 1,3,5-Cyclooctatriene and Phenylmaleimide. When 4d was
heated at 50 °C in toluene in the presence or absence of PPh3,
ring-closure of the ruthenacycle moiety proceeded to give
Scheme 1. Possible Pathways for the Formation of 4

Formation of DiValent Ruthenacycles
Organometallics, Vol. 25, No. 12, 2006 2937
tricyclic product 10, and this involved reductive elimination
between the carbon atoms corresponding to C5 and C8 in Figure
1 (eq 5, Table 1). Without PPh3, the reaction proceeded slowly
to afford 10 in 6% and 18% yield after 1 h and 18 h, respectively
(runs 1 and 2). As shown in runs 3-6, addition of PPh3 faci-
litated the reductive elimination, and the use of 3.0 equiv of
PPh3 gave the product in 31% yield even after 1 h (run 5). In
all cases, only the endo-isomer was obtained, which reflects
retention of the steric structure in 4d. The product 10 can be
regarded as a [6 + 2] cycloadduct of a cot ligand and N-phen-
1
ylmaleimide. H NMR analysis of a toluene-d8 solution of 4d
that was heated at 50 °C for 18 h indicated that 4d was almost
converted and several new complexes as well as 10 seemed to
be formed concurrently. One of the formed complexes was
expected to have 10 as a ligand; however, attempts to isolate
the complexes were unsuccessful, probably due to their instabil-
ity.
Figure 2. ORTEP drawing of 11a. Thermal ellipsoids are shown
at the 50% probability level. Solvent molecules and hydrogen atoms
are omitted for clarity except for those on C1, C6, C7, and C8.
Selected bond distances (Å): Ru1-P1 ) 2.3282(15), Ru1-P2 )
2.3110(17), Ru1-C1 ) 2.226(6), Ru1-C2 ) 2.211(6), Ru1-C3
) 2.247(6), Ru1-C4 ) 2.202(6), Ru1-C5 ) 2.219(6), Ru1-C8
) 2.212(5), C1-C2 ) 1.405(8), C1-C6 ) 1.530(7), C2-C3 )
1.435(9), C3-C4 ) 1.408(10), C4-C5 ) 1.416(8), C6-C7 )
1.550(8), C7-C8 ) 1.563(8).
Table 1. Effect of PPh3 on the Formation of 10 from 4d
run
PPh3 (equiv)
time/h
yield/%a
1
2
3
4
5
6
1
18
1
1
1
6
18
14
18
31
26
1.0
2.0
3.0
5.0
1
a NMR yield.
(c) Reaction of 4 with Bidentate Phosphorus Ligands.
Since the addition of PPh3 was found to accelerate the formation
of 10 from 4d, 1,2-bis(diphenylphosphino)ethane (dppe) was
also used as an additive. However, no 10 was formed in this
case. Instead, a novel ruthenacycle 11a bearing dppe was
obtained, as shown in eq 6, via ligand displacement between
cod and dppe. The reaction of 4c with 1,2-bis(di(o-methoxy-
phenyl)phosphino)ethane gave a similar complex 11b in good
yield. Fine pale yellow single crystals of 11a were obtained by
recrystallization from CH2Cl2/pentane, and the X-ray structure
is shown in Figure 2.
Figure 3. Energy profile for reductive elimination from 4c, B, D,
and F to A, C, E, and G, and for the formation of tricarbonyl
complex 12c from F. The values in parentheses show net activation
energies for the respective steps.
When 11a was heated to 50 °C in toluene for 24 h, no
formation of 10 occurred and 11a remained unreacted. This is
in contrast to the results with the monodentate phosphine PPh3.
We believe that if more than 2 equiv of PPh3 are added to 4d,
the cod ligand would be replaced to form a bis-PPh3 ruthena-
cycle complex, where the steric constraints between PPh3 and
the ruthenacycle moiety would be greater than those in complex
11, which would facilitate reductive elimination.
(33) Bennett, M. A.; Johnson, R. N.; Tomkins, I. B. J. Am. Chem. Soc.
1974, 96, 61.

2938 Organometallics, Vol. 25, No. 12, 2006
Ura et al.
Figure 4. Optimized structures of (a) 4c, TS4c-A, and A, (b) B, TSB-C, and C, (c) D, TSD-E, and E, (d) F, TSF-G, and G, and (e) TSF-12c
and 12c. Selected atomic distances (Å) are shown in each structure.
(d) Reaction of 4 with CO. The reaction of 4 with CO was
also investigated with the expectation of either promoting
reductive elimination or effecting CO insertion into the ruth-
enacycle. Complexes 4d and 4e were treated under CO at 1
atm in toluene and refluxed for 3 h to give tricarbonyl
ruthenacycle complexes 12a in 76% yield and 12b in 73% yield,
respectively (eq 7). In these reactions, cod was fully dissociated
and instead three molecules of CO coordinated to Ru, along
with a change in the hapticity of the cyclooctadienyl moiety
from η5 to η3. The free double-bond moiety of the C8-ring
appeared characteristically in the 13C NMR spectra at 132.4 and
133.4 ppm for 12a and at 129.3 and 132.4 ppm for 12b, while
the coordinated carbon atoms of the C8-ring are normally
observed in the range 50-110 ppm. Treatment of 4e under more

Formation of DiValent Ruthenacycles
Organometallics, Vol. 25, No. 12, 2006 2939
severe reaction conditions such as CO at 40 atm and 120 °C
also afforded only 12b, and products derived from either
reductive elimination or CO insertion were not obtained at all.
The relatively greater steric hindrance of the ruthenacycle
moiety against PMe3 in TSB-C compared to that against dmpe
in TSD-E may explain the difference in energy barriers in the
reductive elimination process. Note that, in the experiment, more
bulky and π-accepting phosphine ligands than PMe3 or dmpe
were used, which would further lower the energy barriers for
the reductive elimination of these complexes in comparison with
the model complexes. The experimental results in eq 5 indicate
that the energy barrier for reductive elimination from the bis-
PPh3 ruthenacycle complex may be even lower than that from
4c, whereas PPh3 might also promote dissociation of the formed
[6 + 2] cycloadduct from ruthenium.
Density Functional Study. The reductive elimination step
from ruthenacycles was investigated theoretically by the DFT
method. As depicted in the upper part of Figure 3, complexes
4c, B, D, and F were used as starting complexes. B is a model
intermediate in the reaction described in eq 5 in the presence
of PPh3, and D is a model complex of 11. Dicarbonyl complex
F, which can be regarded as an intermediate in the formation
of tricarbonyl complex 12c (X ) NMe), was also investigated
for comparison. A, C, E, and G are corresponding zerovalent
diene complexes formed via reductive elimination from 4c, B,
D, and F, respectively. The geometries of the stable complexes
Conclusion
The synthesis, structure, and reactivity of novel ruthenacycles
formed via oxidative cyclization of carbon-carbon double-bond
moieties of 1,3,5-cyclooctatriene and maleic anhydride or
maleimides were reported. These ruthenacycles were shown to
be intermediates in transition metal-mediated [6 + 2] cycload-
dition, and the cycloaddition could be performed in a stepwise
manner. The spectator ligands were experimentally shown to
have significant steric and electronic effects upon reductive
elimination from the ruthenacycles, and moreover, the results
were supported theoretically by DFT calculation. These findings
may contribute to the further understanding of metal-mediated
or -catalyzed [6 + 2] cycloaddition and to the development of
novel catalytic transformation reactions via metallacycle inter-
mediates.
4c, A-G, and 12c and transition states TS4c-A, TSB-C, TSD-E
,
TSF-G, and TSF-12c were optimized by the B3LYP method with
a basis set composed of the combination of SDD for Ru and
6-31G(d,p) for all other atoms. The energy profile (∆E0) is
shown in the lower part of Figure 3, and the optimized structures
are shown in Figure 4.
The ligand displacement of cod in 4c with PMe3, dmpe, or
CO is thermodynamically favorable. The energy barrier of
Experimental Section
TS4c-A is 26.1 kcal/mol, which was lower than those of TSB-C
,
Materials and Methods. All manipulations were performed
under an argon atmosphere using standard Schlenk techniques. All
solvents were distilled under argon over appropriate drying reagents
(sodium, calcium hydride, sodium benzophenoneketyl, or calcium
chloride). Ru(η4-cod)(η6-cot) (3)15c,21 and N-p-methoxyphenylma-
leimide34 were prepared as reported in the literature.
Physical and Analytical Measurements. NMR spectra were
recorded on JEOL EX-400 (FT, 400 MHz (1H), 100 MHz (13C))
and AL-300 (FT, 300 MHz (1H), 75 MHz (13C)) spectrometers.
Chemical shift values (δ) for 1H and 13C are referenced to internal
solvent resonances and reported relative to SiMe4. IR spectra were
recorded on a Nicolet Impact 410 FT-IR spectrometer. Melting
points were measured under argon on a Yanagimoto micro melting
point apparatus.
TSD-E, and TSF-G. In TS4c-A, the bond distances between Ru
and two carbon atoms (corresponding to C5 and C8 in Figure
1) increase from 2.270 and 2.288 to 2.603 and 2.670 Å, and
the distance between these carbon atoms shortens from 2.886
to 2.099 Å. The geometry of A reveals that a new C-C single
bond is formed to build a tricyclic skeleton, and one of the
carbonyl groups of the succinimide moiety has weak interaction
with Ru to occupy the vacant coordination site, to form a twisted
structure. In B and D, the bond angles of P-Ru-P are 94.511°
and 83.365°, respectively, which reflects the steric difference.
The energy barrier for reductive elimination from bis-mono-
phosphine complex B (39.2 kcal/mol) is slightly lower than that
from diphosphine complex D (41.8 kcal/mol). This difference
is consistent with the experimental results, where PPh3 and dppe
correspond to mono- and diphosphine, respectively. The barrier
of TSF-G was estimated to be 32.5 kcal/mol, which is lower
than those of TSB-C and TSD-E. However, there is an alterna-
tive, almost spontaneous, pathway from F to tricarbonyl complex
12c via TSF-12c, and this is also consistent with the experimental
results shown in eq 7, where reductive elimination did not take
place. In TSF-12c, the hapticity of the cyclooctadienyl moiety
is already converted from η5 to η3, and it has a structure that is
partially similar to that in 12c.
As expected, CO was revealed to have a greater ability to
stabilize the divalent ruthenacycle species than cod, PMe3, or
dmpe. It is generally accepted that reductive elimination is
facilitated by strong π-accepting ligands such as CO. However,
in our system, TS4c-A and TSF-G showed an opposite order of
the energy barrier. This result can be explained by steric factors;
that is, in TS4c-A, the steric hindrance of the ruthenacycle moiety
against cod is greater than that against CO in TSF-G, and overall
reductive elimination from 4c has a lower barrier than that from
F.
Synthesis of Ruthenacycles 4a-e. Ruthenacycles 4a-e were
synthesized in a similar manner. The following procedure for 4a
is representative.
Complex 4a. Into a 20 mL, two-necked Pyrex flask with a
stirring bar were placed complex 3 (221 mg, 0.70 mmol) and maleic
anhydride (69 mg, 0.70 mmol) under an argon atmosphere. Hexane
(5.0 mL) was then added, and the suspension was magnetically
stirred at 40 °C for 2 h. The resulting pale yellow precipitate was
filtered by a G4-glass filter, washed three times with 3 mL of Et2O,
and dried under vacuum to give the title complex 4a (194 mg, 67%)
as a pale yellow solid. Mp: 144-146 °C (dec). IR (KBr disk):
1
1993, 1802, 1739, 1237, 1221 cm-1. H NMR (400 MHz, CD2-
Cl2): δ 6.60 (t, J ) 7.3 Hz, 1H, CH of cyclooctadienyl), 5.10 (t,
J ) 8.5 Hz, 1H, CH of cyclooctadienyl), 4.28 (d, J ) 4.8 Hz, 1H,
CH of cyclooctadienyl), 4.25 (d, J ) 5.2 Hz, 1H, RuCH), 4.06
(dd, J ) 10.4, 6.4 Hz, 1H, CH of cyclooctadienyl), 3.81 (d, J )
7.2 Hz, 1H, RuCHCH), 3.59-3.55 (m, 2H, CH of cod), 3.18 (dt,
J ) 4.7, 7.9 Hz, 1H, CH of cod), 3.03 (ddd, J ) 2.1, 6.7, 8.7 Hz,
1H, CH of cod), 3.04 (t, J ) 6.6 Hz, 1H, CH of cyclooctadienyl),
(34) Roderick, W. R. J. Am. Chem. Soc. 1957, 79, 1710.

2940 Organometallics, Vol. 25, No. 12, 2006
Ura et al.
2.72-2.56 (m, 3H, CH2 of cod and CH of cyclooctadienyl), 2.14-
2.04 (m, 2H, CH2 of cod), 1.95-1.80 (m, 4H, CH2 of cod and
cyclooctadienyl), 1.72 (ddt, J ) 16.1, 14.2, 4.7 Hz,1H, CH2 of
cyclooctadienyl), 1.64-1.57 (m, 1H, CH2 of cod), 1.13-1.09 (m,
1H, CH2 of cyclooctadienyl), 0.41 (dt, J ) 4.9, 14.2 Hz, 1H, CH2
of cyclooctadienyl). 13C NMR (100 MHz, CD2Cl2): δ 183.5 (Cd
O), 178.3 (CdO), 106.3 (CH of cyclooctadienyl), 101.5 (CH of
cyclooctadienyl), 99.6 (CH of cyclooctadienyl), 92.1 (CH of cod),
88.5 (CH of cod), 86.6 (CH of cyclooctadienyl), 81.9 (CH of cod),
78.9 (CH of cod), 64.6 (RuCHCH), 64.4 (CH of cyclooctadienyl),
41.7 (CH of cyclooctadienyl), 34.7 (CH2 of cod), 33.3 (CH2 of
cod), 29.8 (RuCH), 29.6 (CH2 of cod), 28.6 (CH2 of cod), 23.5
(CH2 of cyclooctadienyl), 23.1 (CH2 of cyclooctadienyl). HR-MS
(FAB-mNBA): calcd for C20H23O3Ru 413.0691, found 413.0682
(M+ - H).
cyclooctadienyl), 4.38 (d, J ) 6.8 Hz, 1H, RuCH), 4.27-4.17 (m,
2H, CH of cyclooctadienyl), 3.88 (dt, J ) 4.4, 8.3 Hz, 1H, CH of
cod), 3.84 (d, J ) 6.3 Hz, 1H, RuCHCH), 3.60 (dt, J ) 8.8, 4.4
Hz, 1H, CH of cod), 3.29 (t, J ) 6.3 Hz, 1H, CH of cod), 3.19-
3.10 (m, 2H, CH of cyclooctadienyl and cod), 2.85-2.76 (m, 1H,
CH2 of cod), 2.70 (dt, J ) 9.3, 4.3 Hz, 1H, CH of cyclooctadienyl),
2.55 (dq, J ) 19.0, 6.9 Hz, 1H, CH2 of cod), 2.26-2.21 (m, 2H,
CH2 of cod), 2.00-1.79 (m, 5H, CH2 of cyclooctadienyl and cod),
1.61-1.52 (m, 1H, CH2 of cyclooctadienyl), 1.27-1.22 (m, 1H,
CH2 of cod), 0.54 (dt, J ) 6.5, 13.3 Hz, 1H, CH2 of cyclooctadi-
enyl). 13C NMR (100 MHz, CD2Cl2): δ 189.4 (CdO), 180.3 (Cd
O), 134.1 (CAr), 128.9 (2C, CAr), 127.6 (CAr), 127.1 (2C, CAr), 105.2
(CH of cyclooctadienyl), 101.1 (CH of cyclooctadienyl), 99.7 (CH
of cyclooctadienyl), 92.5 (CH of cod), 89.3 (CH of cod), 87.7 (CH
of cyclooctadienyl), 79.5 (CH of cod), 76.8 (CH of cod), 64.3 (CH
of cyclooctadienyl), 62.7 (RuCHCH), 40.2 (CH of cyclooctadienyl),
35.2 (CH2 of cod), 33.2 (RuCH), 32.4 (CH2 of cod), 30.6 (CH2 of
cod), 28.4 (CH2 of cod), 23.3 (CH2 of cyclooctadienyl), 23.2 (CH2
of cyclooctadienyl). Anal. Calcd for C26H29NO2Ru: C, 63.91; H,
5.98; N, 2.87. Found: C, 63.75; H, 5.93; N, 3.06.
Complex 4b: pale yellow solid, mp 126-128 °C (dec). IR (KBr
1
disk): 3146, 1720, 1673, 1446, 1347, 1172 cm-1. H NMR (400
MHz, CDCl3): δ 8.12 (br s, NH), 6.53 (t, J ) 7.1 Hz, 1H, CH of
cyclooctadienyl), 5.12 (t, J ) 8.5 Hz, 1H, CH of cyclooctadienyl),
4.19 (d, J ) 6.8 Hz, 1H, RuCH), 4.13 (d, J ) 4.9 Hz, 2H, CH of
cyclooctadienyl), 3.83 (dt, J ) 4.6, 8.4 Hz, 1H, CH of cod), 3.78
(d, J ) 6.3 Hz, 1H, RuCHCH), 3.58 (br t, J ) 6.1 Hz, 1H, CH of
cod), 3.18-3.13 (m, 2H, CH of cyclooctadienyl and cod), 2.97 (t,
J ) 7.3 Hz, 1H, CH of cod), 2.85-2.63 (m, 3H, CH2 of cod and
CH of cyclooctadienyl), 2.29-2.19 (m, 1H, CH2 of cod), 2.04 (br
t, J ) 11.6 Hz, 1H, CH2 of cod), 1.97-1.76 (m, 5H, CH2 of
cyclooctadienyl and cod), 1.65-1.57 (m, 1H, CH2 of cod), 1.21-
1.14 (m, 1H, CH2 of cyclooctadienyl), 0.50 (dt, J ) 5.2, 14.0 Hz,
1H, CH2 of cyclooctadienyl). 13C NMR (100 MHz, CDCl3): δ 190.9
(CdO), 181.6 (CdO), 105.0 (CH of cyclooctadienyl), 100.9 (CH
of cyclooctadienyl), 99.6 (CH of cyclooctadienyl), 92.6 (CH of cod),
89.5 (CH of cod), 87.8 (CH of cyclooctadienyl), 79.5 (CH of cod),
76.7 (CH of cod), 65.6 (RuCHCH), 62.4 (CH of cyclooctadienyl),
39.8 (CH of cyclooctadienyl), 35.4 (CH2 of cod), 34.7 (RuCH),
32.2 (CH2 of cod), 30.5 (CH2 of cod), 28.6 (CH2 of cod), 23.2
(CH2 of cyclooctadienyl), 23.1 (CH2 of cyclooctadienyl). HR-MS
(FAB-mNBA): calcd for C20H24NO2Ru 412.0851, found 412.0831
(M+ - H).
Complex 4e: pale yellow solid, mp 139-141 °C (dec). IR (KBr
1
disk): 1708, 1676, 1512 1302, 1250, 1171 cm-1. H NMR (400
MHz, CD2Cl2): δ 7.38 (d, J ) 8.8 Hz, 2H, HAr), 7.03 (d, J ) 8.8
Hz, 2H, HAr), 6.58 (t, J ) 6.8 Hz, 1H, CH of cyclooctadienyl),
5.15 (t, J ) 8.6 Hz, 1H, CH of cyclooctadienyl), 4.28 (d, J ) 6.8
Hz, 1H, RuCH), 4.24-4.17 (m, 2H, CH of cyclooctadienyl), 3.86
(s, 3H, OCH3), 3.83-3.80 (m, 1H, CH of cod), 3.80 (d, J ) 6.8
Hz, 1H, RuCHCH), 3.61 (br t, J ) 4.4 Hz, 1H, CH of cod), 3.22-
3.14 (m, 2H, CH of cyclooctadienyl and CH of cod), 3.06 (t, J )
7.4 Hz, 1H, CH of cod), 2.75-2.68 (m, 2H, CH of cyclooctadienyl
and CH2 of cod), 2.56-2.46 (m, 1H, CH2 of cod), 2.26-2.23 (m,
2H, CH2 of cod), 2.00-1.78 (m, 4H, CH2 of cyclooctadienyl and
CH2 of cod), 1.53 (br s, 1H, CH2 of cod), 1.26-1.21 (m, 1H, CH2
of cyclooctadienyl), 0.55 (dt, J ) 14.0, 9.5 Hz, 1H, CH2 of cod).
13C NMR (100 MHz, CD2Cl2): δ 189.6 (CdO), 180.6 (CdO),
159.1 (CAr), 128.8 (2C, CAr), 127.5 (CAr), 114.3 (2C, CAr), 105.4
(CH of cyclooctadienyl), 101.5 (CH of cyclooctadienyl), 100.2 (CH
of cyclooctadienyl), 92.9 (CH of cod), 89.5 (CH of cod), 88.1 (CH
of cyclooctadienyl), 79.5 (CH of cod), 76.6 (CH of cod), 64.7
(RuCHCH), 63.0 (CH of cyclooctadienyl), 55.8 (OCH3), 40.6 (CH
of cyclooctadienyl), 35.5 (CH2 of cod), 33.7 (RuCH), 32.5 (CH2
of cod), 30.9 (CH2 of cod), 28.6 (CH2 of cod), 23.6 (CH2 of
cyclooctadienyl), 23.5 (CH2 of cyclooctadienyl). HR-MS (FAB-
mNBA): calcd for C27H30NO3Ru 518.1269, found 518.1290 (M+
- H).
Synthesis of N-Phenylcyclooctylsuccinimide 8. Into a 20 mL,
two-necked Pyrex flask with a stirring bar and a reflux condenser
was placed 4d (244 mg, 0.50 mmol) under a H2 atmosphere.
Toluene (5 mL) was then added, and the solution was magnetically
stirred at 120 °C for 6 h. The resulting dark brown precipitate was
removed by a G4-glass filter, and the filtrate was purified by column
chromatography with functionalized silica gel. Removal of solvents
gave 8 (80 mg, 56%) as a white solid. Mp: 112-115 °C (dec). IR
(KBr disk): 1741, 1689, 1513, 1301, 1250, 1171 cm-1.1H NMR
(400 MHz, CDCl3): δ 7.47 (tt, J ) 7.6, 1.5 Hz, 2H), 7.39 (tt, J )
7.6, 1.6 Hz, 1H), 7.27 (dd, J ) 7.6, 1.2 Hz, 2H), 2.99 (ddd, J )
9.3, 4.4, 3.4 Hz, 1H), 2.87 (dd, J ) 18.3, 9.3 Hz, 1H), 2.63 (dd, J
) 18.3, 4.4 Hz, 1H), 2.44-2.35 (m, 1H), 1.80-1.41 (m, 14H).
13C NMR (100 MHz, CDCl3): δ 178.6 (CdO), 176.1 (CdO),
132.0, 129.1 (2C), 128.5, 126.4 (2C), 47.1, 37.8, 32.2, 31.2, 28.5,
26.4, 26.3 (2C), 26.0, 25.4. HR-MS (FAB-mNBA): calcd for
C18H24NO2 286.1807, found 286.1810 (M+ + H).
Complex 4c: pale yellow solid, mp 129-132 °C (dec). IR (KBr
1
disk): 1729, 1663, 1439, 1383, 1267 cm-1. H NMR (400 MHz,
CD2Cl2): δ 6.51 (dd, J ) 8.3, 6.8 Hz, 1H, CH of cyclooctadienyl),
5.10 (t, J ) 8.3 Hz, 1H, CH of cyclooctadienyl), 4.18 (d, J ) 6.8
Hz, 1H, RuCH), 4.10 (dd, J ) 6.8, 10.3 Hz, 1H, CH of
cyclooctadienyl), 4.02 (dd, J ) 6.3, 10.3 Hz, 1H, CH of cyclooc-
tadienyl), 3.84 (dt, J ) 4.2, 8.4 Hz, 1H, CH of cod), 3.65 (d, J )
6.3 Hz, 1H, RuCHCH), 3.59-3.53 (m, 1H, CH of cod), 3.23 (s,
3H, NCH3), 3.19 (t, J ) 6.6 Hz, 1H, CH of cyclooctadienyl), 3.09
(dd, J ) 8.3, 13.2 Hz, 1H, CH of cod), 2.89-2.79 (m, 2H, CH and
CH2 of cod), 2.64-2.54 (m, 2H, CH of cyclooctadienyl and CH2
of cod), 2.26-2.17 (m, 2H, CH2 of cod), 2.01 (br t, J ) 12.0 Hz,
1H, CH2 of cod), 1.94-1.80 (m, 4H, CH2 of cyclooctadienyl and
cod), 1.66-1.57 (m, 1H, CH2 of cod), 1.25-1.13 (m, 1H, CH2 of
cyclooctadienyl), 0.50 (dt, J ) 6.0, 13.6 Hz, 1H, CH2 of cyclooc-
tadienyl). 13C NMR (100 MHz, CD2Cl2): δ 191.0 (CdO), 181.1
(CdO), 105.0 (CH of cyclooctadienyl), 100.9 (CH of cycloocta-
dienyl), 99.7 (CH of cyclooctadienyl), 92.2 (CH of cod), 89.1 (CH
of cod), 87.1 (CH of cyclooctadienyl), 79.3 (CH of cod), 76.8 (CH
of cod), 64.3 (RuCHCH), 62.5 (CH of cyclooctadienyl), 39.7 (CH
of cyclooctadienyl), 35.2 (CH2 of cod), 33.7 (RuCH), 32.2 (CH2
of cod), 30.8 (CH2 of cod), 28.5 (CH2 of cod), 24.6 (NCH3), 23.2
(CH2 of cyclooctadienyl), 23.2 (CH2 of cyclooctadienyl). HR-MS
(FAB-mNBA): calcd for C21H26NO2Ru 426.1007, found 426.0995
(M+ - H).
Synthesis of N-Phenyl(3,5-cyclooctadien-1-yl)succinimide 9.
Into a 20 mL, two-necked Pyrex flask with a stirring bar was placed
4d (146 mg, 0.30 mmol) under an argon atmosphere. Et2O (1.5
mL) and 1.0 M HCl (Et2O solution, 1.5 mL) were added, and the
suspension was magnetically stirred at room temperature for 3 h.
Complex 4d: pale yellow solid, mp 129-134 °C (dec). IR (KBr
1
disk): 1732, 1677, 1499, 1379, 1157 cm-1. H NMR (400 MHz,
CD2Cl2): δ 7.55-7.33 (m, 5H, HAr), 6.55 (t, J ) 7.1 Hz, 1H, CH
of cyclooctadienyl), 5.12 (dd, J ) 7.3, 9.3 Hz, 1H, CH of

Formation of DiValent Ruthenacycles
Organometallics, Vol. 25, No. 12, 2006 2941
The resulting pale orange solid was filtered off by a G4-glass filter.
The filtrate was chromatographed on silica gel, and elution with
Et2O gave a pale yellow solution, from which the solvent was
evaporated to give 9 (52 mg, 62%) as a white solid. Mp: 101-
104 °C. IR (KBr disk): 2922, 1779, 1703, 1593, 1501, 1457, 1391,
of cyclooctadienyl), 24.6 (CH2 of cyclooctadienyl). HR-MS (FAB-
mNBA): calcd for C44H41NO2P2Ru 779.1656, found 779.1669
(M+).
Complex 11b: pale yellow solid, mp 145-147 °C (dec). IR (KBr
disk): 1725, 1711, 1664, 1650, 1512, 1433, 1298, 1157, 1092 cm-1
.
1
1262 cm-1. H NMR (400 MHz, CD2Cl2): δ 7.50 (t, J ) 7.2 Hz,
1H NMR (300 MHz, CD2Cl2): δ 8.05 (dt, J ) 1.5, 7.6 Hz, 1H,
HAr), 7.98 (ddd, J ) 1.3, 7.5, 13.8 Hz, 1H, HAr), 7.63 (ddd, J )
1.7, 7.3, 14.8 Hz, 1H, HAr), 7.42 (dt, J ) 1.0, 8.1 Hz, 1H, HAr),
7.30 (dt, J ) 1.3, 7.8 Hz, 1H, HAr), 7.24-7.14 (m, 3H, HAr), 7.07
(t, J ) 7.7 Hz, 1H, HAr), 7.04 (t, J ) 7.4 Hz, 2H, HAr), 6.80-6.68
(m, 3H), 6.69 (t, J ) 7.2 Hz, 1H, CH of cyclooctadienyl), 6.60
(dd, J ) 1.7, 8.3 Hz, 1H, HAr), 6.53 (d, J ) 8.3 Hz, 1H, HAr),
5.10-5.03 (m, 1H, CH of cyclooctadienyl), 4.97 (dt, J ) 8.5, 4.8
Hz, 1H, CH of cyclooctadienyl), 4.32 (q, J ) 8.3, Hz, 1H, CH of
cyclooctadienyl), 3.80-3.66 (m, 1H, PCH2), 3.64-3.56 (m, 1H,
RuCHCH), 3.37 (d, J ) 6.8 Hz, 1H, RuCH), 3.26 (s, 3H, OCH3),
3.24 (s, 3H, OCH3), 3.14 (s, 3H, OCH3), 3.00 (s, 3H, OCH3), 2.93-
2.74 (m, 2H, CH of cyclooctadienyl and PCH2), 2.61-2.32 (m,
1H, PCH2), 2.26 (s, 3H, NCH3), 2.24-2.16 (m, 1H, CH of
cyclooctadienyl), 1.70-1.44 (m, 2H, CH2 of cyclooctadienyl),
1.15-1.07 (m, 1H, CH2 of cyclooctadienyl), 0.92-0.76 (m, 1H,
PCH2), 0.61 (dt, J ) 4.8, 13.8 Hz, 1H, CH2 of cyclooctadienyl).
13C NMR (75 MHz, CD2Cl2): δ 193.0 (CdO), 182.6 (CdO),
160.3-110.3 (CAr), 98.1 (CH of cyclooctadienyl), 96.2 (CH of
cyclooctadienyl), 89.1 (CH of cyclooctadienyl), 77.9 (d, JCP ) 18.1
Hz, CH of cyclooctadienyl), 64.7 (d, JCP ) 8.1 Hz, RuCH), 55.2
2H), 7.42 (d, J ) 7.2 Hz, 1H), 7.27 (d, J ) 7.6 Hz, 2H), 5.91 (d,
J ) 10.8 Hz, 2H), 5.80-5.64 (m, 2H), 3.05 (dt, J ) 9.3, 4.9 Hz,
1H), 2.87 (dd, J ) 18.6, 9.3 Hz, 1H), 2.61 (dd, J ) 18.3, 4.9 Hz,
1H), 2.56-2.38 (m, 1H), 2.29 (br s, 1H), 2.19-2.02 (m, 3H), 1.74
(br t, J ) 11.7 Hz, 1H), 1.33 (br q, J ) 11.7 Hz, 1H). 13C NMR
(100 MHz, CD2Cl2): δ 178.5 (CdO), 175.8 (CdO), 132.5 (CAr),
131.5, 129.8, 129.3 (2C, CAr), 128.8 (CAr), 127.2, 126.9 (2C, CAr),
126.7, 46.1, 35.1, 31.7, 31.3, 28.5, 27.0. HR-MS (FAB-mNBA):
calcd for C18H20NO2 282.1494, found 282.1482 (M+ + H).
Formation of 10. Into a 30 mL, two-necked Pyrex flask with a
stirring bar was placed 4d (244 mg, 0.50 mmol) under an argon
atmosphere. Toluene (10 mL) was added, and the dark green
solution was magnetically stirred at 50 °C for 18 h. The reaction
mixture was evaporated, and the residue was purified by silica gel
column chromatography (hexane/ethyl acetate, 1:1) to give 10 (18
mg, 13%) as a white solid after drying. Mp: 178-180 °C (dec).
IR (KBr disk): 2923, 2854, 1706, 1459,1377 cm-1. 1H NMR (300
MHz, CDCl3): δ 7.45 (tt, J ) 7.4, 1.5 Hz, 2H), 7.37 (tt, J ) 7.4,
1.5 Hz, 1H), 7.25 (dd, J ) 7.4, 1.5 Hz, 2H), 5.81 (dt, J ) 12.3, 3.5
Hz, 2H), 5.65-5.55 (m, 2H), 3.27 (dt, J ) 8.4, 6.0 Hz, 2H), 3.13-
3.02 (m, 2H), 2.28-2.13 (m, 2H), 1.99-1.83 (m, 2H). 13C NMR
(75 MHz, CDCl3): δ 177.4 (2C, CdO), 132.1, 130.8 (2C), 129.0
(2C), 128.4, 126.8 (2C), 126.4 (2C), 44.0 (2C), 31.4 (2C), 25.5
(2C). HR-MS (FAB-mNBA): calcd for C18H18NO2 280.1338, found
280.1336 (M+ + H).
(OCH3), 55.2 (OCH3), 55.0 (OCH3), 54.9 (OCH3), 50.4 (d, JCP
34.8 Hz, CH of cyclooctadienyl), 40.2 (CH of cyclooctadienyl),
28.2 (RuCHCH), 26.3 (d, JCP ) 15.6 Hz, PCH2), 25.9 (d, JCP
)
)
10.0 Hz, PCH2), 25.2 (CH2 of cyclooctadienyl), 24.9 (CH2 of
cyclooctadienyl), 24.9 (NCH3). HR-MS (FAB-mNBA): calcd for
C43H47NO6P2Ru 837.1922, found 837.1947 (M+).
Synthesis of Complexes 12a and 12b. Complexes 12a and 12b
were synthesized in a similar manner. The following procedure for
12a is representative.
Synthesis of Complexes 11a and 11b. Complexes 11a and 11b
were synthesized in a similar manner. The following procedure for
11a is representative.
Complex 12a. Into a 20 mL, two-necked Pyrex flask equipped
with a stirring bar and a reflux condenser was placed complex 4d
(244 mg, 0.50 mmol) under a CO atmosphere. Toluene (10 mL)
was then added, and the suspension was magnetically stirred at
120 °C for 3 h. After removal of the solvent, Et2O (2.0 mL) and
hexane (2.0 mL) were added to the residue, and the resulting solid
was collected by a G4-glass filter, washed (4 × 2 mL of hexane),
and dried under vacuum to give complex 12a (174 mg, 76%) as a
pale yellow solid. Mp: 156-159 °C (dec). IR (KBr disk): 2085,
Complex 11a. Into a 20 mL, two-necked Pyrex flask with a
stirring bar were placed complex 4d (244 mg, 0.50 mmol) and 1,2-
bis(diphenylphosphino)ethane (199 mg, 0.50 mmol) under an argon
atmosphere. THF (5.0 mL) was then added, and the solution was
magnetically stirred at 40 °C for 6 h. The reaction mixture was
chromatographed on alumina, and elution with THF gave a yellow
solution from which the solvent was evaporated. The resulting
yellow solid was reprecipitated from Et2O/hexane and filtered by
a G4-grass filter, washed (4 × 3 mL of hexane), and dried under
vacuum to give 11a (221 mg, 57%): pale yellow solid, mp 150-
153 °C (dec). IR (KBr disk): 1723, 1658, 1499, 1432, 1383, 1368,
1156, 1093 cm-1. 1H NMR (400 MHz, CDCl3): δ 7.70 (t, J ) 8.3
Hz, 2H, HAr), 7.49-7.18 (m, 16H, HAr), 7.08 (t, J ) 6.6 Hz, 1H,
HAr), 6.98 (t, J ) 8.1 Hz, 2H, HAr), 6.94 (t, J ) 6.6 Hz, 2H, HAr),
6.88 (d, J ) 7.8 Hz, 2H, HAr), 6.50 (t, J ) 6.6 Hz, 1H, CH of
cyclooctadienyl), 4.87-4.82 (m, 1H, CH of cyclooctadienyl), 4.78
(t, J ) 8.1 Hz, 1H, CH of cyclooctadienyl), 4.50 (dt, J ) 8.8, 7.9
Hz, 1H, CH of cyclooctadienyl), 3.75-3.73 (m, 1H, RuCHCH),
3.60 (d, J ) 7.3 Hz, 1H, RuCH), 3.23-3.03 (m, 2H, CH of
cyclooctadienyl and PCH2), 2.83-2.68 (m, 2H, CH of cycloocta-
dienyl and PCH2), 1.90-1.82 (m, 1H, CH2 of cyclooctadienyl),
1.75-1.65 (m, 1H, CH2 of cyclooctadienyl), 1.54-1.36 (m, 2H,
PCH2), 1.29-1.26 (m, 1H, CH2 of cyclooctadienyl), 0.67 (dt, J )
4.4, 13.9 Hz, 1H, CH2 of cyclooctadienyl). 13C NMR (100 MHz,
CDCl3): δ 190.6 (CdO), 180.9 (CdO), 140.9-126.1 (CAr), 99.1
(CH of cyclooctadienyl), 93.2 (d, JCP ) 2.5 Hz, CH of cyclooc-
tadienyl), 93.1 (s, CH of cyclooctadienyl), 79.0 (d, JCP ) 17.5 Hz,
CH of cyclooctadienyl), 63.9 (d, JCP ) 8.3 Hz, RuCH), 48.3 (d,
JCP ) 34.2 Hz, CH of cyclooctadienyl), 41.9 (CH of cyclooctadi-
enyl), 29.2 (dd, JCP ) 30.9, 18.3 Hz, PCH2), 29.0 (d, JCP ) 5.8
Hz, RuCHCH), 28.0 (dd, JCP ) 28.4, 14.2 Hz, PCH2), 24.8 (CH2
1
2016, 2001, 1746, 1681, 1378, 1165, 1016 cm-1. H NMR (400
MHz, CD2Cl2): δ 7.45 (dt, J ) 1.6, 6.7 Hz, 2H, HAr), 7.36 (tt, J
) 1.6, 7.3 Hz, 1H, HAr), 7.31 (dd, J ) 1.5, 7.3 Hz, 2H, HAr), 6.13
(dd, J ) 10.5, 3.2 Hz, 1H, free dCH), 5.71 (dq, J ) 0.8, 8.8 Hz,
1H, free dCH), 5.03 (br d, J ) 7.3 Hz, 1H, CH of cyclooctadienyl),
4.94 (t, J ) 8.3 Hz, 1H), 4.90 (dt, J ) 1.6, 8.3 Hz, 1H, CH of
cyclooctadienyl), 3.52-3.42 (m, 1H, CH of cyclooctadienyl), 3.02
(dd, J ) 8.8, 3.6 Hz, 1H, RuCHCH), 2.66-2.55 (m, 1H, CH2 of
cyclooctadienyl), 2.34 (d, J ) 8.8 Hz, 1H, RuCH), 2.32-2.26 (m,
1H, CH2 of cyclooctadienyl), 1.82 (ddt, J ) 14.0, 6.2, 2.0 Hz, 1H,
CH2 of cyclooctadienyl), 1.63 (dddd, J ) 14.2, 12.7, 5.4, 2.0 Hz,
1H, CH2 of cyclooctadienyl). 13C NMR (100 MHz, CD2Cl2): δ
197.9 (RuCO), 194.7 (RuCO), 188.8 (CdO), 185.7 (RuCO), 180.7
(CdO), 133.4 (free CdC), 132.4 (free CdC), 129.4 (CAr), 128.9
(2C, CAr), 127.9 (CAr), 126.9 (2C, CAr), 97.8 (CH of cyclooctadi-
enyl), 79.7 (CH of cyclooctadienyl), 66.1 (CH of cyclooctadienyl),
63.4 (RuCHCH), 42.0 (CH of cyclooctadienyl), 35.3 (RuCH), 32.7
(CH2 of cyclooctadienyl), 25.7 (CH2 of cyclooctadienyl). HR-MS
(FAB-mNBA): calcd for C21H18NO5Ru 466.0228, found 466.0237
(M+ + H).
Complex 12b: pale yellow solid, mp 154-156 °C (dec). IR (KBr
disk): 2089, 2018, 2010, 1747, 1684, 1512, 1384, 1249, 1165, 1101,
1
1028 cm-1. H NMR (400 MHz, CDCl3): δ 7.21 (d, J ) 8.8 Hz,

2942 Organometallics, Vol. 25, No. 12, 2006
Ura et al.
Crystallography.35 All calculations were carried out with a Japan
SGI workstation computer using the CrystalStructure crystal-
lographic software package.36,37
Table 2. Summary of Crystal Data, Collection Data, and
Refinement of 4e and 11a
4e
11a
Theoretical Calculations. To consistently compare the single-
point energies of model complexes, calculations were carried out
using density functional theory (DFT)-optimized geometries.
Calculations were performed using the Gaussian 03 RevB.0438
implementation of B3LYP [Becke three-parameter exchange func-
tional (B3)39 and the Lee-Yang-Parr correlation functional
(LYP)40] on Intel PIV computers at Kyoto University. The basis
set consisted of the combination of the Stuttgart-Dresden-Bonn
energy-consistent pseudopotential (SDD)41 for Ru and the 6-31G-
(d,p) basis set for all other atoms. No constraints were imposed
for any of the systems. Frequency calculations on optimized species
established that the energy minima possessed only real frequencies
and the transition states possessed a single imaginary frequency.
Zero-point energy and thermodynamic functions were computed
at standard temperature (298.15 K) and pressure (1 atm). Spatial
plots of the optimized geometries were obtained from Gaussian 03
output using Cambridge Soft Corporation’s Chem 3D Pro v4.0.
formula
fw
C27H31NO3Ru
518.62
yellow
C44H41NO2P2Ru‚CH2Cl2
863.76
yellow
cryst color
habit
cryst size, mm
cryst syst
space group
a, Å
prism
block
0.20 × 0.10 × 0.10
orthorhombic
Pbca (#61)
15.4164(9)
13.1723(7)
21.0485(4)
90
90
90
4274.3(3)
8
1.612
0.15 × 0.15 × 0.10
triclinic
P1h (#2)
10.4811(13)
15.523(3)
24.0006(12)
90.466(7)
91.225(3)
93.021(8)
3898.3(9)
4
b, Å
c, Å
R, deg
â, deg
γ, deg
V, Å3
Z
D(calcd), g cm-3
data collection
temp, °C
1.472
-130
-80
µ(Mo KR), cm-1
2θ max, deg
no. of measd
reflns
7.651
55.0
23 658
6.612
54.8
28 588
Acknowledgment. This work was supported in part by
Grants-in-Aid for Scientific Research (A), (B), Scientific
Research on Priority Areas, and the 21st century COE program,
COE for a United Approach to New Materials Science, from
the Japan Society for the Promotion of Science and the Ministry
of Education, Culture, Sports, Science and Technology, Japan.
T.K. acknowledges financial support from the Sumitomo
Foundation and the Japan Chemical Innovation Institute. We
thank Dr. M. Shiro (Rigaku Corp.) for supporting our X-ray
crystallography. This research (project) was partly conducted
in the Advanced Research Institute of Environmental Material
Control Engineering, Katsura-Int’tech Center, Graduate School
of Engineering, Kyoto University.
no. of unique
reflns
4862 (Rint ) 0.148)
15 192 (Rint ) 0.069)
no. of obsd reflns
(I > 2σ(I))
no. of variables
R1a (I > 2σ(I))
wR2a (I > 2σ(I))
R1a (all data)
wR2a (all data)
GOF
2723
10 070
320
1041
0.042
0.066
0.107
0.113
1.047
0.073
0.131
0.120
0.150
0.978
2
2
2
a R1 ) ∑||Fo| - |Fc||/∑|Fo|; wR2 ) [∑(w(Fo - Fc )2)/∑w(Fo )2]1/2
.
2H, HAr), 6.96 (d, J ) 8.8 Hz, 2H, HAr), 6.12 (dd, J ) 10.3, 2.9
Hz, 1H, free dCH), 5.70 (dt, J ) 10.4, 8.0 Hz, 1H, free dCH),
5.02 (br d, J ) 6.4 Hz, 1H, CH of cyclooctadienyl), 4.93 (t, J )
8.4 Hz, 1H, CH of cyclooctadienyl), 4.89 (t, J ) 8.4 Hz, 1H, CH
of cyclooctadienyl), 3.82 (s, 3H, OCH3), 3.44 (br s, 1H, CH of
cyclooctadienyl), 3.00 (dd, J ) 8.8, 3.6 Hz, 1H, RuCHCH), 2.66-
2.53 (m, 1H, CH2 of cyclooctadienyl), 2.33 (d, J ) 8.8 Hz, 1H,
RuCH), 2.30-2.26 (m, 1H, CH2 of cyclooctadienyl), 1.85-1.78
(m, 1H, CH2 of cyclooctadienyl), 1.63 (dt, J ) 5.2, 12.4 Hz, 1H,
CH2 of cyclooctadienyl). 13C NMR (100 MHz, CDCl3): δ 198.0
(RuCO), 194.8 (RuCO), 188.8 (CdO), 185.9 (RuCO), 180.9 (Cd
O), 159.1 (CAr), 132.4 (free CdC), 129.3 (free CdC), 128.0 (2C,
CAr), 126.1 (CAr), 114.2 (2C, CAr), 97.8 (CH of cyclooctadienyl),
79.7 (CH of cyclooctadienyl), 66.0 (CH of cyclooctadienyl), 63.3
(RuCHCH), 55.8 (OCH3), 42.0 (CH of cyclooctadienyl), 35.2
(RuCH), 32.7 (CH of cyclooctadienyl), 25.7 (CH2 of cyclooctadi-
enyl). Anal. Calcd for C22H19NO6Ru: C, 53.44; H, 3.87; N, 2.83.
Found: C, 53.44; H, 3.87; N, 2.99.
Supporting Information Available: X-ray crystallographic files
(CIF) for complexes 4e and 11a and results of the theoretical
calculations. This material is available free of charge via the Internet
at http://pubs.acs.org.
OM060242T
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Crystallographic Study of Complexes 4e and 11a. Crystals
that were stable for X-ray diffraction measurements and were
obtained by recrystallization from CHCl3/pentane for 4e and CH2-
Cl2/pentane for 11a were mounted on glass fibers. The diffraction
data were collected with a Rigaku RAPID imaging plate area
detector, using graphite-monochromated Mo KR radiation (λ )
0.71069 Å) with the oscillation technique. Crystal data and
experimental details are listed in Table 2. All structures were solved
by a combination of direct methods and Fourier techniques. Non-
hydrogen atoms were anisotropically refined by full-matrix least
squares calculations. Refinements were continued until all shifts
were smaller than one-tenth of the standard deviations of the
parameters involved. Atomic scattering factors and anomalous
dispersion terms were taken from the International Tables for X-ray
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