Ligand displacement reaction of Ru(η4-1,5-COD)(η6-1,3,5-COT) with Lewis bases

Article abstract of DOI:10.1021/om030064t

Reactions of Ru(η⁴-1,5-COD)(η⁶-1,3,5-COT) (1) (COD = cyclooctadiene, C₈H₁₂; COT = cyclooctatriene, C₈H₁₀) with a series of Lewis bases are studied. Treatments of 1 with P(OMe)₃, P(OEt)₃, P(OMe)₂Ph, P(OEt)₂Ph, P(OⁱPr)₃, P(OMe)Ph₂, or P(OEt)Ph₂ lead to the formation of Ru(η⁴-1,5-COD)(η⁴-1,3,5-COT)L (2) followed by preferential liberation of the 1,5-COD ligand to give COT complexes formulated as Ru(6-η¹:1-3-η³-COT)L₃ (3) and Ru(η⁴-1,3,5-COT)L₃ (4). Reaction of 1 with P(OPh)₃ also gives 2, but further treatment of this system leads to the liberation of both 1,5-COD and 1,3,5-COT to give a mixture of Ru(η⁴-1,5-COD)L₃ (5) and Ru(6-η¹:1-3-η³-COT)L₃ (3) and finally gives Ru{P(OC₆H₄)(OPh)₂}₂- {P(OPh)₃}₂ (6h). In the reaction of 1 with tert-butylisonitrile, 1,3,5-COT is initially liberated with concomitant formation of Ru(η⁴-1,5-COD)(CN^tBu)₃ (5j), which further reacts with the liberated 1,3,5-COT, giving eventually Ru(6-η¹:1-3-η³-COT)(CN^tBu)₃ (3j). The molecular structure of 5j determined by X-ray structure analysis reveals that one of the isonitrile ligands has a considerable carbene character. In the presence of excess isonitrile, the homoleptic complex Ru(CN^tBu)₅ (7) is formed. On the other hand, 1 does not react with poor π-accepting ligands such as NEt₃, pyridine, and (dimethylamino)pyridine as well as bulky phosphorus ligands such as triphenylphosphine and tricyclohexylphosphine. These results suggest that the initial coordination of electron-donating ligands to Ru essentially encourages the dissociation of the 1,5-COD ligand, but the π-accepting ability of the ligand induces the dissociation of the 1,3,5-COT ligand.

Full text of DOI:10.1021/om030064t

2378
Organometallics 2003, 22, 2378-2386
Liga n d Disp la cem en t Rea ction of
Ru (η4-1,5-COD)(η6-1,3,5-COT) w ith Lew is Ba ses
Masafumi Hirano, Rie Asakawa, Chifumi Nagata, Takashi Miyasaka,
Nobuyuki Komine, and Sanshiro Komiya*
Department of Applied Chemistry, Faculty of Technology, Tokyo University of Agriculture and
Technology, 2-24-16 Nakacho, Koganei, Tokyo 184-8588, J apan
Received J anuary 28, 2003
Reactions of Ru(η4-1,5-COD)(η6-1,3,5-COT) (1) (COD ) cyclooctadiene, C8H12; COT )
cyclooctatriene, C8H10) with a series of Lewis bases are studied. Treatments of 1 with
P(OMe)3, P(OEt)3, P(OMe)2Ph, P(OEt)2Ph, P(OiPr)3, P(OMe)Ph2, or P(OEt)Ph2 lead to the
formation of Ru(η4-1,5-COD)(η4-1,3,5-COT)L (2) followed by preferential liberation of the
1,5-COD ligand to give COT complexes formulated as Ru(6-η1:1-3-η3-COT)L3 (3) and Ru-
(η4-1,3,5-COT)L3 (4). Reaction of 1 with P(OPh)3 also gives 2, but further treatment of this
system leads to the liberation of both 1,5-COD and 1,3,5-COT to give a mixture of Ru(η4-
1,5-COD)L3 (5) and Ru(6-η1:1-3-η3-COT)L3 (3) and finally gives Ru{P(OC6H4)(OPh)2}2-
{P(OPh)3}2 (6h ). In the reaction of 1 with tert-butylisonitrile, 1,3,5-COT is initially liberated
with concomitant formation of Ru(η4-1,5-COD)(CNtBu)3 (5j), which further reacts with the
liberated 1,3,5-COT, giving eventually Ru(6-η1:1-3-η3-COT)(CNtBu)3 (3j). The molecular
structure of 5j determined by X-ray structure analysis reveals that one of the isonitrile ligands
has a considerable carbene character. In the presence of excess isonitrile, the homoleptic
complex Ru(CNtBu)5 (7) is formed. On the other hand, 1 does not react with poor π-accepting
ligands such as NEt3, pyridine, and (dimethylamino)pyridine as well as bulky phosphorus
ligands such as triphenylphosphine and tricyclohexylphosphine. These results suggest that
the initial coordination of electron-donating ligands to Ru essentially encourages the
dissociation of the 1,5-COD ligand, but the π-accepting ability of the ligand induces the
dissociation of the 1,3,5-COT ligand.
In tr od u ction
alkylations,9 reductive cleavage of allylic esters,10 tail-
to-tail dimerization of acrylonitrile,11 Z-selective isomer-
ization of 2-allylphenol,12 carbonylation of allylic car-
bonates,13 preparation of cyclohexanones from allylic
compounds with â-keto esters,14 and dimerization of
norbornadiene involving C-C bond cleavage15 in the
presence of suitable σ-donors or π-acceptors. In these
reactions, initial displacement or partial dissociation of
the cyclic polyene ligands is considered to be a possible
prerequisite entry step. However, the ligand displace-
ment process of 1 by Lewis bases is relatively unex-
plored to date at a molecular level, although initial facile
reaction is usually formation of an adduct Ru(η4-1,5-
COD)(η4-1,3,5-COT)L, which is followed by various
further reactions. Published examples of the ligand
Ru(η4-1,5-COD)(η6-1,3,5-COT) (1)1,2 is regarded as a
versatile zerovalent ruthenium complex with two labile
cyclic polyene ligands.3 Complex 1 is known to catalyze
remarkable reactions such as [2+2] cross addition of
norbornadiene and acetylenes,4 co-dimerization of acety-
lenes with 1,3-dienes5 or alkenes,6 Z-selective formation
of butatriene,7 co-cycloaddition of allylic amine,8 allylic
* Corresponding author. Tel: +81 423 887 043. Fax: +81 423 877
500. E-mail: komiya@cc.tuat.ac.jp.
(1) Abbreviations: COD ) cyclooctadiene (C8H12), COT ) cyclooc-
tatriene (C8H10), DPPM
)
1,1-bis(diphenylphosphino)methane
(C25H22P2), DMAP ) 4-N,N-dimethylaminopyridiene (C7H10N2).
(2) Synthesis of 1: (a) Fisher, E. O.; Mu¨ller, J . Chem. Ber. 1963,
96, 3217. (b) Pertici, P.; Vitulli, G.; Porri, L. J . Chem. Soc., Chem.
Commun. 1975, 846. (c) Pertici, P.; Vitulli, G.; Paci, M.; Porri, L. J .
Chem. Soc., Dalton Trans. 1980, 1961. (d) Itoh, K.; Nagashima, H.;
Ohshima, T.; Oshima, N.; Nishiyama, H. J . Organomet. Chem. 1984,
272, 179. (e) Frosin, K.-M.; Dahlenburg, L. Inorg. Chim. Acta 1990,
167, 83.
(8) Mitsudo, T.; Zhang, S.-W.; Satake, N.; Kondo, T.; Watanabe, Y.
Tetrahedron Lett. 1992, 33, 5533.
(9) Zhang, S.-W.; Mitsudo, T.; Kondo, T.; Watanabe, Y. J . Orga-
nomet. Chem. 1993, 450, 197.
(3) (a) Mitsudo, T.; Hori, Y.; Watanabe, Y. J . Organomet. Chem.
1987, 334, 157. (b) Pertici, P.; Vitulli, G. Comments Inorg. Chem. 1991,
11, 175. (c) Bennett, M. A. In Comperhensive Organometallic Chemistry
II; Abel, E. W., Stone, F. G. A., Wilkinson, G., Bruce, M. I., Eds.;
Pergamon: Oxford, 1995; Vol. 7, p 549.
(4) Mitsudo, T.; Kokuryo, K.; Shinsugi, T.; Nakagawa, Y.; Watanabe,
Y.; Takegami, Y. J . Org. Chem. 1979, 44, 4492.
(5) Mitsudo, T.; Nakagawa, Y.; Watanabe, K.; Hori, Y.; Misawa, H.;
Watanabe, H.; Watanabe, Y. J . Org. Chem. 1985, 50, 565.
(6) Mitsudo, T.; Zhang, S.-W.; Nagao, M.; Watanabe, Y. J . Chem.
Soc., Chem. Commun. 1991, 598.
(7) Wakatsuki, Y.; Yamazaki, H.; Kumegawa, N.; Satoh, T.; Satoh,
J . Y. J . Am. Chem. Soc. 1991, 113, 9604.
(10) Maruyama, Y.; Sezaki, T.; Tekawa, M.; Sakamoto, T.; Shimizu,
I.; Yamamoto, A. J . Organomet. Chem. 1994, 473, 257.
(11) Fukuoka, A.; Nagano, T.; Furuta S.; Yoshizawa, M.; Hirano,
M.; Komiya, S. Bull. Chem. Soc. J pn. 1998, 71, 1409.
(12) Sato, T.; Komine, N.; Hirano, M.; Komiya, S. Chem. Lett. 1999,
441.
(13) Mitsudo, T.; Suzuki, N.; Kondo, T.; Watanabe, Y. J . Org. Chem.
1994, 59, 7759.
(14) Zhang, S.-W.; Mitsudo, T.; Kondo, T.; Watanabe, Y. J . Orga-
nomet. Chem. 1995, 485, 55.
(15) Mitsudo, T.; Suzuki, T.; Zhang, S.-W.; Imai, D.; Fujita, K.;
Manabe, T.; Shiotsuki, M.; Watanabe, Y.; Wada, K.; Kondo, T. J . Am.
Chem. Soc. 1999, 121, 1839.
10.1021/om030064t CCC: $25.00 © 2003 American Chemical Society
Publication on Web 05/09/2003

Reaction of Ru(η4-1,5-COD)(η6-1,3,5-COT)
Organometallics, Vol. 22, No. 12, 2003 2379
Ta ble 1. Su m m a r y for th e Rea ction of 1 w ith
Tr ia lk yl P h osp h ite, P h osp h on ite, a n d
P h osp h in itesa
Sch em e 1
yield (%)
ligand
cone angle (deg)
conv (%)
3
4
P(OMe)3
P(OEt)3
107
109
115
116
130
132
133
100
100
100
100
100
100
100
44
36
13
11
8
49
40
61
77
48
53
52
P(OMe)2Ph
P(OEt)2Ph
P(OiPr)3
P(OMe)Ph2
P(OEt)Ph2
17
16
a
Conditions: 1 (0.049-0.0720 mmol), phosphorus compound (3
equiv), C6D6 (0.6 mL), 50 °C, 20-24 h.
(2a )25 (96% yield). Further inspection of the spectrum
revealed the formation of an additional small amount
of a 6-η1:1-3-η3-COT complex, Ru(6-η1:1-3-η3-COT)-
{P(OMe)3}3 (3a ) (4% yield). Longer treatment of this
system at 50 °C for 24 h eventually gave a mixture of
3a and Ru(η4-1,3,5-COT){P(OMe)3}3 (4a ) in 44% and
49% yields, respectively, by preferential liberation of the
1,5-COD ligand. As shown in Scheme 1, we previously
reported the exclusive liberation of the 1,5-COD ligand
in the reaction of 1 with monodentate tertiary phos-
phine, giving either 6-η1:1-3-η3-COT or η4-1,3,5-COT
complex depending on the phosphine employed.22,23 The
1H NMR spectral characteristic of these coordination
modes is that the 6-η1:1-3-η3-COT ligand has a se-
quence of 1-, 2-, and 3-CH protons in the allylic region
(typically δ 3.0-5.0) and the η4-1,3,5-COT has a couple
of low-field resonances (typically δ 4.5-5.0) due to 2-
and 3-CH and a couple of high-field resonances (typi-
cally δ 2.5-3.0) due to 1- and 4-CH, which is a reflection
of the contribution of the LX2 (πσ2) coordination mode
(vide infra). Since, in both cases, they have conspicuous
uncoordinated olefinic protons (2H) around δ 5.0-6.0,
the other resonances can be easily assigned one after
another by their spin correlations based on these olefinic
displacement include reactions of 1 with arene under
H2 giving Ru(η4-1,5-COD)(η6-arene),16-19 with CO giving
Ru(η4-1,5-COD)(CO)3,20 and with DPPM giving Ru(η4-
1,5-COD)(DPPM-κ2P,P′)(DPPM-κ1P),21 where all ex-
amples preferentially liberate the 1,3,5-COT ligand
without exception. From these results, the 1,3,5-COT
ligand had been considered to be more labile than the
1,5-COD ligand in general. Despite these facts, we
recently exploited the first examples of exclusive sub-
stitution of the 1,5-COD ligand by the reaction of 1 with
a series of monodentate tertiary phosphines (Scheme
1).22,23
Mitsudo et al. also documented the second example
of the preferential liberation of the 1,5-COD ligand by
the reaction of 1 with electron-deficient olefins.15,24
Thus, the 1,5-COD ligand does not always act as a
spectator ligand in substitution reaction of 1, although
the process is likely to correlate with the mechanisms
of the catalyses promoted by the combination of 1 with
Lewis bases. We report herein the reactions of 1 with
various monodentate Lewis bases to elucidate the
controlling factors in the ligand displacement reaction
of 1.
1
protons by use of H-1H COSY. Thus, these coordina-
Resu lts
tion modes can be unambiguously characterized spec-
troscopically. For complex 3a , the uncoordinated olefinic
protons assignable to 4- and 5-CH appear at δ 5.7-5.8
(m, 2H) and the correlated allylic signals at δ 5.0 (br,
1H) and 4.7 (m, 2H), which are assignable to the 1-CH
resonance and 2- and 3-CH resonances, respectively,
indicating the 6-η1:1-3-η3-COT coordination mode. On
the other hand, complex 4a shows correlated signals at
δ 6.34 (t, 1H) and 5.1-5.3 (m, 3H) assignable to the
5-CH and merged 2-, 3-, and 6-CH. Although the 1- and
4-CH resonances were accidentally obscured by the
POMe signals in the 1H NMR spectrum, the 1H-1H
COSY clearly indicated these resonances appeared at
δ 3.3-3.4. The complex 4a was therefore characterized
as a η4-1,3,5-COT complex. The corresponding COD
complex Ru(η4-1,5-COD)L3 was not observed through
the reaction. By the preparative-scale reaction of 1 with
P(OMe)3, complex 3a was fortunately isolated as ana-
lytically pure white crystals in 18% yield.
1. Rea ction of 1 w ith P h osp h ites, P h osp h on ites,
a n d P h osp h in ites. Ligand substitution reactions of 1
with a series of phosphorus compounds such as alkyl
phosphites, phosphonites, and phosphinites were carried
out (Scheme 2 and Table 1). When P(OMe)3 was added
into a C6D6 solution of 1 at 50 °C, complex 1 completely
disappeared within 10 min, giving a known monophos-
phite complex, Ru(η4-1,5-COD)(η4-1,3,5-COT){P(OMe)3}
(16) (a) Pertici, P.; Simonelli, G.; Vitulli, G.; Deganello, G.; Sandrini,
P.; Mantovani, A. J . Chem. Soc., Chem. Commun. 1977, 132. (b) Pertici,
P.; Vitulli, G.; Lazzaroni, R.; Salvadori, P.; Barili, P. L. J . Chem. Soc.,
Dalton Trans. 1982, 1019.
(17) Pertici, P.; Vitulli, G.; Bertozzi, S.; Lazzaroni, R. Inorg. Chim.
Acta 1988, 149, 235.
(18) Vitulli, G.; Pertici, P.; Salvadori, P. J . Chem. Soc., Dalton Trans.
1984, 2255.
(19) Hirano, M.; Shibasaki, T.; Komiya, S.; Bennett, M. A. Organo-
metallics 2002, 21, 5738.
(20) Deganello, G.; Mantovani, A.; Sandrini, P. L.; Pertici, P.; Vitulli,
G. J . Organomet. Chem. 1977, 135, 215.
(21) Chaudret, B.; Commenges, G.; Poilblanc, R. J . Chem. Soc.,
Dalton Trans. 1984, 1635.
(22) Hirano, M.; Marumo, T.; Miyasaka, T.; Fukuoka, A.; Komiya,
S. Chem. Lett. 1997, 297.
(23) Komiya, S.; Planas, J . G.; Onuki, K.; Lu, Z.; Hirano, M.
Organometallics 2000, 19, 4051.
The other phosphorus compounds such as P(OEt)3,
P(OMe)2Ph, P(OEt)2Ph, P(OiPr)3, P(OMe)Ph2, and P(O-
Et)Ph2 also tend to encourage the exclusive liberation
(24) Shiotsuki, M.; Suzuki, T.; Kondo, T.; Wada, K.; Mitsudo, T.
Organometallics 2000, 19, 5733.
(25) Pertici, P.; Vitulli, G.; Porzio, W.; Zocchi, M.; Barili, P. L.;
Deganello, G. J . Chem. Soc., Dalton Trans. 1983, 1553.

2380 Organometallics, Vol. 22, No. 12, 2003
Hirano et al.
Sch em e 2
Sch em e 3
were liberated. Further treatment of the mixture of 3h
and 5h with 3 equiv of P(OPh)3 at 50 °C for 7 days led
to the formation of 6h in 92% yield. Thus, 3h and 5h
are regarded as intermediates in the formation of 6h .
Two hydrogens lost in this reaction are consumed as
both hydrogen gas and hydrogenation of cyclic olefins,
since H2 gas (40%) was detected by Toepler pump and
the GLC analysis revealed formation of cyclooctane
(30%), 1,3-COD (29%), 1.5-COD (59%), and 1,3,5-COT
(41%). The orthometalation probably takes place after
formation of a coordinative unsaturated homoleptic
phosphite complex such as “Ru{P(OPh)3}4”. Similarly,
reaction of 1 with 4 equiv of P(OC6H4Cl-4)3 also gave
the homoleptic orthometalated complex Ru{P(OC6H3-
Cl-4)(OC6H4Cl-4)2}2{P(OC6H4Cl-4)3}2 (6i) in 41% yield.
2. Rea ction of 1 w ith Ison itr ile a n d CO. Similarly
to the above reactions, treatment of 1 with CNtBu
(3 equiv) initially gave Ru(η4-1,5-COD)(η4-1,3,5-COT)(CNt-
Bu) (2j) in quantitative yield (26% isolated yield). In this
case, however, further reaction caused preferential
liberation of 1,3,5-COT to give Ru(η4-1,5-COD)(CNtBu)3
(5j) in 58% yield (Scheme 4).27 Since pure yellow single
crystals of 5j were obtained from the acetone solution,
the molecular structure of 5j was determined by X-ray
structure analysis, and the ORTEP drawing and se-
lected bond distances and angles are shown in Figure 1
and Table 2, respectively.
The molecular structure of 5j unambiguously indi-
cates that the 1,5-COD ligand remains as a spectator
ligand and three isonitrile ligands coordinate to the
ruthenium center. It is notable that one of the three
isonitrile ligands is significantly bent at N(1) [C(9)-
N(1)-C(10) ) 132.5(6)°], indicating strong back-dona-
tion to this isonitrile ligand from the ruthenium.
Consistently, the bond distance Ru(1)-C(9) [1.906(6) Å]
is shorter than the other Ru(1)-C(14) [1.941(6) Å] or
Ru(1)-C(19) [2.020(6) Å], and N(1)-C(9) [1.210(8) Å]
of 1,5-COD to form a mixture of 3b-g and 4b-g as
shown in Table 1, although these reactions were some-
what complex because of concomitant formation of
unidentified species.
When a triaryl phosphite P(OPh)3, which is the
strongest π-acceptors among phosphites employed, was
reacted with 1, the substitution reaction proceeded to
give Ru(η4-1,5-COD)(η4-1,3,5-COT){P(OPh)3} (2h ), fol-
lowed by formation of Ru(6-η1:1-3-η3-COT){P(OPh)3}3
(3h ) and Ru(η4-1,5-COD){P(OPh)3}3 (5h ), and finally the
known orthometalated complex Ru{P(OC6H4)(OPh)2}2-
{P(OPh)3}2 (6h )26 (Scheme 3). When 4 equiv of P(OPh)3
per 1 was reacted at 50 °C for 18 h, a mixture of 3h
and 5h was formed in 46% and 23% yields, respectively,
although they could not be separated from each other.
The NMR study revealed that this reaction initially
gave 2h in quantitative yield, from which both 1,5-COD
and 1,3,5-COT were liberated at almost the same rate
as one another giving 3h and 5h independently. When
the 2:1 mixture of 3h and 5h was treated with an excess
amount of I2 for 3 h at room temperature, both 1,5-COD
(71% based on 5h ) and 1,3,5-COT (82% based on 3h )
(27) Complex 5j was spectroscopically reported by the treatment of
Ru(η6-naphthalene)(η4-1,5-COD) with CNtBu: Bennett, M. A.; Lu, Z.;
Wang, X.; Bown, M.; Hockless, D. C. R. J . Am. Chem. Soc. 1998, 120,
10409.
(26) (a) Preece, M.; Robinson, S. D.; Wingfield, J . N. J . Chem. Soc.,
Dalton Trans. 1976, 613. (b) Tolman, C. A.; English, A. D.; Ittel, S. D.;
J esson, J . P. Inorg. Chem. 1978, 17, 2374.

Reaction of Ru(η4-1,5-COD)(η6-1,3,5-COT)
Organometallics, Vol. 22, No. 12, 2003 2381
Ch a r t 1
signals assignable to the endo- and exo-methylene and
1
a methine protons for 1,5-COD in the H NMR. In the
13C{1H} NMR spectrum, one set of signals due to the
CNCMe3 moiety and one set of methylene and methine
carbons for 1,5-COD are observed in benzene-d6. This
symmetric feature suggests that three isonitrile moieties
are apparently equivalent in solution, due to facile
exchange among the three isonitrile ligands and rotation
of the 1,5-COD moiety on the NMR time scale.
As shown above, reaction of 1 with 3 equiv of CNtBu
gave the 1,5-COD complex 5j by preferential liberation
of 1,3,5-COT, but unexpectedly further heating of this
reaction mixture at 50 °C afforded Ru(6-η1:1-3-η3-
COT)(CNtBu)3 (3j) in 56% yield for 23 h, during which
5j completely disappeared. Complex 3j can also be
prepared by the reaction of isolated 5j with 2 equiv of
1,3,5-COT in 54% yield. Therefore, the reaction is
considered to be a stepwise reaction. The ligand dis-
placement reaction of 1,5-COD by 1,3,5-COT was re-
tarded not by the added 1,5-COD but by the addition of
CNtBu. This result suggests that an initial loss of CNt-
Bu to create a vacant site at ruthenium for incoming
1,3,5-COT is an important prior step for the reaction.
These experiments show that the initial coordination
of isonitrile encourages preferential liberation of 1,3,5-
COT in 2j to give 5j, but further displacement of the
1,5-COD ligand of 5j by 1,3,5-COT leading to 3j may be
caused by the higher thermodynamic stability of 3j than
5j. When an excess amount of CNtBu was treated with
1 at 50 °C, a known homoleptic isonitrile complex, Ru-
(CNtBu)5 (7),29 was formed in 32% yield. Therefore, the
reaction is considered to be a successive reaction in
which the once liberated 1,3,5-COT re-coordinated to
ruthenium to give 3j eventually.
F igu r e 1. Molecular structure of Ru(η4-1,5-COD)(CNtBu)3
(5j). All hydrogen atoms are omitted for clarity. Ellipsoids
represent 50% probability.
Sch em e 4
Ta ble 2. Selected Bon d Dista n ces a n d An gles for
Ru (η4-1,5-COD)(CNtBu )3 (5j)
Bond Distances (Å)
Ru(1)-C(1)
Ru(1)-C(5)
Ru(1)-C(9)
Ru(1)-C(19)
N(1)-C(10)
N(2)-C(15)
N(3)-C(20)
C(2)-C(3)
2.179(5)
2.256(6)
1.906(6)
2.020(6)
1.484(8)
1.454(8)
1.446(7)
1.530(9)
1.52(1)
Ru(1)-C(2)
Ru(1)-C(6)
Ru(1)-C(14)
N(1)-C(9)
N(2)-C(14)
N(3)-C(19)
C(1)-C(8)
C(3)-C(4)
C(5)-C(6)
C(7)-C(8)
2.200(6)
2.265(6)
1.941(6)
1.210(8)
1.163(8)
1.157(8)
1.516(9)
1.52(1)
Sandrini et al. reported reaction of 1 with CO to form
Ru(η4-1,5-COD)(CO)3 (5k ) via Ru(η4-1,5-COD)(η4-1,3,5-
COT)(CO) (2k ), and further treatment of this system
with excess CO eventually gave Ru3(CO)12 (8).20 When
1
we monitored this experiment by H NMR, formation
of Ru(6-η1:1-3-η3-COT)(CO)3 (3k ) and Ru(η4-1,5-COD)-
(CO)3 (5k ) was observed after formation of 2k , although
this reaction was not clean due to uncharacterized side
reactions. In this reaction, however, formation of both
3k and 5k as well as liberation of both 1,5-COD and
1,3,5-COT took place at almost the same rate, suggest-
ing the reaction is not a successive reaction but a
parallel one (Scheme 5).
C(4)-C(5)
1.385(10)
1.51(1)
C(6)-C(7)
1.496(9)
Bond Angles (deg)
C(9)-N(1)-C(10)
C(19)-N(3)-C(20)
132.5(6)
176.5(6)
Ru(1)-C(14)-N(2) 178.0(5)
C(14)-N(2)-C(15)
176.9(7)
178.6(5)
Ru(1)-C(9)-N(1)
Ru(1)-C(19)-N(3) 176.9(5)
is a little bit longer than the others. The IR spectrum
of 5j shows three ν(CN) bands at 2126, 2102, and 1847
cm-1, the latter low value also reflecting strong π-back-
donation. By taking account of these features, one of
the isonitrile ligands is considered to have dominant
contributions from a carbene structure as depicted in
Chart 1.
Lewis and co-workers also reported the formation of
5k by the reaction of Ru3(CO)12 with 1,5-COD.30 Since
(28) Seddon, E. A.; Seddon, K. R. In The Chemistry of Ruthenium;
Clark, R. J . H., Ed.; Topics in Inorganic and General Chemistry, A
Collection of Monographs, Monograph 19; Elsevier: Amsterdam, 1984;
p 944.
Similar carbenoic features of the isonitrile ligand are
also observed for other reported ruthenium(0) isonitrile
complexes.28 In solution, however, complex 5j shows one
singlet resonance assignable to the tBu moiety and three
(29) Barker, G. K.; Galas, A. M. R.; Green, M.; Howard, J . A. K.;
Stone, F. G. A.; Turney, T. W.; Welch, A. J .; Woodward, P. J . Chem.
Soc., Chem. Commun. 1977, 256.
(30) Domingos, A. J .; J ohnson, B. F. G.; Lewis, J . J . Chem. Soc.,
Dalton Trans. 1975, 2288.

2382 Organometallics, Vol. 22, No. 12, 2003
Hirano et al.
Sch em e 5
they reported that the bicyclic polyene complex Ru(η4-
bicyclo[4.2.0]octa-2,4-diene)(CO)3 is exclusively formed
by the reaction of 5k with 1,3,5-COT and we did not
see this product at all in our case, 3k is formed directly
from 2k but not from 5k . Although the reaction with
CO is a bit complicated, CO is considered to encourage
liberation of both 1,5-COD and 1,3,5-COT ligands in 2k .
3. R ea ct ion s of 1 w it h a n N-Don or Liga n d .
Contrary to the reaction with ligands described above,
1 did not react with nitrogen donors such as NEt3,
pyridine, nor DMAP at all. Complex 1 also did not react
with acetonitrile. However, the treatment of 1 with
acrylonitrile gave an insoluble complex formulated as
Ru(COT)(AN)3 by liberation of 1,5-COD as reported
previously as an active species of catalytic dimerization
of acrylonitrile by us.11 Athough insolubility of Ru(COT)-
(AN)3 to organic solvent prevented further characteriza-
tion, acrylonitrile probably coordinates to the ruthenium
in an η2-CdC fashion since acetonitrile did not react
with 1 at all.
F igu r e 2. Relationship between ν(CO) value of Ni(CO)3L
(electronic factor) and cone angle (steric factor)31 in the
ligand substitution reactions of 1.
of these ligands, which discourages coordination to the
highly reduced ruthenium center.
It is also interesting to rationalize the trend with
which the cyclic polyene ligand is displaced. As seen in
Figure 2, a strong donor favors the loss of the COD
ligand, giving Ru(COT)L3 type complexes, but coordina-
tion of strong π-acceptor ligands such as triaryl phos-
phite, isonitrile, and CO causes liberation of the COT
ligand. One extreme is highly π-accepting isonitrile,
which initially liberates only 1,3,5-COT, giving Ru-
(COD)L3, which slowly displaces again the 1,5-COD
ligand by 1,3,5-COT (vide infra). The selectivity is
conveniently interpreted by considering the stability of
cyclic polyene ligands in the monophosphine adduct 2
in the following way. The more electron-donating ligand
such as tertiary phosphines reduces the ruthenium
center to cause efficient back-bonding to cyclic polyene
ligands. Thus, the LX2 (or πσ2) contribution in the COT
ligand as shown in eq 1 increases to stabilize the
bonding between COT and Ru.
Discu ssion
As relatively well established, the reaction of 1 with
Lewis bases commonly gives an intermediate formu-
lated as Ru(η4-1,5-COD)(η4-1,3,5-COT)L (2) as an initial
step. Then, displacement of the cyclic polyene ligands
is considered to take place. Selectivity was highly
dependent on L employed. To rationalize the ligand
displacement selectivity, the trends in initial adduct
formation and in structural preference in the COT
moiety in resulting Ru(COT)L3 are visualized in Figure
2.31
As we have shown for the reactions of tertiary
phosphines, only Lewis bases of cone angle smaller than
145° can react with 1 to give monoligand adduct
complexes 2. The sterically bulky ligands such as PPh3
and PCy3 did not react at all with 1 probably because
of the lack of enough space for coordination on Ru
regardless of the electronic properties of the ligands.22
On the other hand, N-donor ligands also showed no
reactivity with 1. It is worthwhile to note that the
following order of π-acceptor strength is generally
accepted: CO > RNC > P(OR)3 > PR3 > RCN > NR3.32
Thus, this may be due to lack of π-accepting property
This influence is considered to be larger in COT than
that in COD, since back-bonding may be more efficient
for the conjugated π-system than the nonconjugated one.
On the other hand, if L is highly electron-withdrawing
such as isonitrile, electron density at Ru considerably
decreases. Therefore, the LX2 (or πσ2) contribution in
the COT ligand diminishes. It is not clear why displace-
ment of the COT ligand is enhanced in this case, but
sterically better matching of the η4-1,5-COD coordina-
tion than the η4-1,3,5-COT to Ru(0) may be a possible
reason because the chelation of nonconjugated dienes
is generally believed to introduce rigidity to increase the
binding constant to the metal.33
The difference in coordination mode of the COT ligand
in products is another interesting subject to discuss.
Trialkyl phosphites, phosphonites, and phosphinites
(31) Tolman, C. A. Chem. Rev. 1977, 77, 313.
(32) Elschenbroich, C.; Salzer, A. In Organometallics. A Concise
Introduction, 2nd, revised ed.; VCH: Weinheim, 1992; p 230.
(33) Crabtree, R. H. In The Organometallic Chemistry of the
Transition Metals, 3rd ed.; Wiley: New York, 2001; p 129.

Reaction of Ru(η4-1,5-COD)(η6-1,3,5-COT)
Organometallics, Vol. 22, No. 12, 2003 2383
essentially liberate 1,5-COD from 2 to give a mixture
of Ru(6-η1:1-3-η3-COT)L3 (3) and Ru(η4-1,3,5-COT)L3
(4), whereas monodentate phosphines exclusively gave
either 3 or 4 depending on L. The more compact
phosphines such as trimethylphosphine and dimeth-
ylphenylphosphine gave only 3, but relatively bulky
phosphines such as triethylphosphine afford 4.22 Al-
though the product ratios in the cases of trialkyl
phosphite, phosphonite, and phosphinite ligands were
not accurately estimated, the yield of 3 tends to decrease
with decrease in the cone angle of L, as shown in Table
2. Formation of these COT complexes 3 and 4 probably
proceeded by a parallel reaction, although the detailed
mechanism is not clear at present. One of the evidences
for the parallel reaction is that while treatment of 1 with
P(OMe)3 gave an approximate 1:1 mixture of 3a and 4a ,
a preliminary reaction of Ru(η5-cyclooctadieneyl)2 with
P(OMe)3 mainly gave 3a .
Displacement of 1,5-COD ligand in Ru(η4-1,5-COD)-
(CNtBu)3 (5j) by 1,3,5-COT needs some comments.
Although 1,3,5-COT is initially displaced by CNtBu,
coordination of three CNtBu enhances exchange of 1,5-
COD by 1,3,5-COT. It is noteworthy that the 1,3,5-COT
ligand came back to the Ru as a η1:η3-ligand. This is
probably due to thermodynamic stability of the product,
and this phenomenon can be explained as follows. As
shown in the X-ray and IR data of 5j, one of the
isontirile ligands has significant carbene character.
Although the reason why only one of the isonitriles has
intensively received π-back-donation from ruthenium,
this feature may reflect the tendency to become a
ruthenium(II) moiety bearing a carbene ligand. Consis-
tently, a part of the driving force for the exchange
reaction of η4-1,5-COD by η1:η3-COT may be more
effective oxidation of the ruthenium species by forcing
the COT ligand to a η1:η3-mode. When 5j was reacted
with an excess amount of isontirile, 5j favors the
exchange reaction of 1,5-COD by electron-withdrawing
isonitriles to give the homoleptic complex 7.
ligand displacement reactions seems to be removal of
the electron density from the electron-rich ruthenium-
(0) center.
Exp er im en ta l Section
All manipulations and reactions were performed under dry
nitrogen atmosphere with use of standard Schlenk and vacuum
line techniques. Benzene, hexane, and pentane were distilled
over benzophenone ketyl, and acetone was distilled from
Drierite; these solvents were stored under nitrogen. The
complex Ru(η4-1,5-COD)(η6-1,3,5-COT) (1)2d was prepared
according to literature procedures, but magnetic stirring was
used instead of sonication. P(OC6H4Cl-4)3 was prepared by the
reaction of PCl3 with 4-chlorophenol, and 1,3,5-COT was
prepared according to literature procedures.35 All other re-
agents were obtained from commercial suppliers (Wako Pure
Chemical, Kanto, Aldrich, and TCI) and used as received. 1H,
31P{1H}, and 13C{1H} NMR spectra were recorded on a J EOL
LA 300 (300.4 MHz for 1H, 121.6 MHz for 31P, and 75.5 MHz
for 13C) spectrometer. Benzene-d6 and toluene-d8 were distilled
over sodium wires and stored under vacuum and were
transferred into the NMR tube by bulb-to-bulb distillation.
Chemical shifts (δ) are given in ppm, relative to internal TMS
for 1H and 13C and external 85% H3PO4 in deuterated water
for 31P. All coupling constants are given in Hz. Product yields
for reactions in an NMR tube were calculated on the basis of
internal CHPh3 or an external C6D6 solution of PPh3 in a
flame-sealed capillary. HRMS were performed on a J EOL GC-
Mate II by FAB method. Elemental analyses were carried out
on a Perkin-Elmer 2400 series II CHN analyzer.
Rea ction s w ith P (OMe)3. (a) Complex 1 (125.3 mg, 0.3972
mmol) was placed in a Schlenk tube under nitrogen into which
hexane (5 mL) was introduced. Then, P(OMe)3 (141 µL, 1.19
mmol) was added into the solution and warmed at 50 °C for
38 h. After removal of all volatile matters, the resulting white
solid was recrystallized from cold pentane (1 mL) to give white
crystals of Ru(6-η1:1-3-η3-COT){P(OMe)3}3 (3a ) in 18% yield
(40.6 mg, 0.0701 mmol). 1H NMR (300.4 MHz, C6D6): δ 2.0
(br, 1H, 8-CH2), 2.1 (m, 1H, 8-CH2), 2.6 (br, 1H, 6-CH), 2.8
(br, 1H, 7-CH2), 2.9 (br, 1H, 7-CH2), 3.3 (d, J ) 11 Hz, 18H,
equatorial-POMe), 3.6 (dd, J ) 9, 1 Hz, 9H, axial-POMe), 4.7
(m, 2H, 1- and 3-CH), 5.0 (br, 1H, 2-CH), 5.7-5.8 (m, 2H, 5-
and 6-CH). 31P{1H} NMR (121.6 MHz, C6D6): δ 145.6 (t, J )
45 Hz, 1P, axial-P), 159.6 (dd, J ) 61, 45 Hz, 1P, equatorial-
P), 159.7 (dd, J ) 61, 45 Hz, 1P, equatorial-P). Anal. Calcd for
In relation to this consideration, it is notable that the
Ru(6-η1:1-3-η3-COT)P3 is generally more stable than
Ru(η4-1,5-COD)P3.34
C
17H37O9P3Ru: C, 35.24; H, 6.44. Found: C, 35.40; H, 6.49.
When excess CO, isonitrile, and triaryl phosphites
were used, homoleptic complexes were essentially formed
as final products by releasing both COD and COT
ligands. This complete displacement of the ligand may
arise from their extremely strong π-accepting properties,
neutralizing the highly reduced zerovalent ruthenium
center. In the case of P(OAr)3 further oxidation takes
place to give an orthometalation product.
In summary, the displacement reaction of cyclic
polyene ligands in 1 with Lewis bases is delicately
controlled by π-acidity and steric bulk of the Lewis base.
Initial addition of L takes place only when L is compact
and π-acidic. When coordinated L is a strong π-acceptor,
1,3,5-COT tends to be displaced by 3L, whereas a weak
π-acceptor favors the dissociation of 1,5-COD. Two
coordination modes of the 1,3,5-COT ligand in Ru(1,3,5-
COT)L3 are found: one being 6-η1:1-3-η3-COT, the
other being η4-1,3,5-COT. The former coordination mode
is favored by an electron-donating compact ligand, but
the latter by a relatively bulkier ligand. By taking
account of these facts, the prime driving force of these
(b) Complex 1 (15.8 mg, 0.0501 mmol) was placed in an
NMR tube into which C6D6 (0.6 mL) was introduced by bulb-
to-bulb distillation. P(OMe)3 (17.6 µL, 0.150 mmol) was then
added into the NMR tube by a hypodermic syringe, and the
NMR tube was warmed to 50 °C. Within 10 min, complex 1
completely disappeared to form Ru(η4-1,5-COD)(η4-1,3,5-COT)-
{P(OMe)3} (2a ) and 3a in 96% and 4% yields, respectively.
Further treatment of this system at 50 °C for 24 h gave a
mixture of 3a and Ru(η4-1,3,5-COT){P(OMe)3}3 (4a ) in 44%
and 49% yields, respectively. Complexes 2a and 4a were
characterized spectroscopically by use of 1H-1H COSY and
analogy of the related complexes. 2a : 1H NMR (300.4 MHz,
C6D6): δ 1.45 (dd, J ) 15 and 14 Hz 1H), 1.8 (m, 2H), 2.0-2.1
(m, 2H), 2.26 (m, 2H), 2.5 (m, 2H), 2.6 (m, 1H), 3.35 (d, J ) 7
Hz, 9H, POMe), 3.60 (d, J ) 9H, 1H), 4.91 (t, J ) 7 Hz, 1H),
5.1 (m, 2H), 5.94 (t, J ) 9 Hz, 1H). 31P{1H} NMR (121.6 MHz,
C6D6): δ 169.1 (s). 4a : 1H NMR (300.4 MHz, C6D6): δ 1.7 (br,
1H, 8-CH2), 2.0 (m, 1H, 8-CH2), 2.1 (obscured by the signal
due to 3a , 7-CH2) 2.4 (br, 1H, 7-CH2), 3.3-3.4 (obscured by
the signal due to POMe, 1- and 4-CH), 5.1-5.3 (m, 3H, 2-, 3-,
6-CH), 6.34 (t, J ) 9 Hz, 1H, 5-CH). 31P{1H} NMR (121.6 MHz,
C6D6): δ 154 (br, 2P), 169 (br, 1P).
Rea ction s w ith P (OEt)3. (a) Reaction of complex 1 (106.2
(34) Komiya, S.; Hirano, M. Dalton Trans. 2003, 1439.
mg, 0.336 mmol) with P(OEt)3 (162 µL, 0.846 mmol) in hexane

2384 Organometallics, Vol. 22, No. 12, 2003
Hirano et al.
at 50 °C for 22 h followed by workup and recrystallization from
pentane gave a white powder of Ru(6-η1:1-3-η3-COT){P(OEt)3}3
(3b) in 14% yield (32.4 mg, 0.046 mmol). The 1H NMR
spectrum of 3b was characterized by use of 1H-1H COSY and
13C-1H shift correlation spectra. 1H NMR (300.4 MHz, C6D6):
δ 1.11 (t, J ) 8 Hz, 9H, POCH2CH3), 1.24 (t, J ) 8 Hz, 9H,
POCH2CH3), 1.26 (t, J ) 8 Hz, 9H, POCH2CH3),1.98 (m, 1H,
7-CH2), 2.18 (dt, J ) 12, 8 Hz, 1H, 8-CH2), 2.65 (m, 1H, 8-CH2),
2.8 (m, 2H, 6-CH and 7-CH2), 3.79 (dqui, J ) 10, 7 Hz, 3H,
POCH2CH3), 3.86 (dqui, J ) 10, 7 Hz, 3H, POCH2CH3), 4.15
(m, 12H, POCH2CH3), 4.62 (m, 1H, 3-CH), 4.71 (dt, J ) 14, 9
Hz, 1H, 2-CH), 4.86 (m, 1H, 1-CH), 5.77 (m, 1H, 5-CH), 5.88
(m, 1H, 4-CH). 13C{1H} (75.5 MHz, C6D6): δ 16.5 (d, J ) 6 Hz,
POCH2CH3), 16.6 (d, J ) 6 Hz, POCH2CH3), 25.8 (dd, J ) 7,
3 Hz, 8-CH2), 43.7 (dt, J ) 91, 11 Hz, 6-CH), 48.1 (dd, J ) 8,
5 Hz, 7-CH2), 59.2 (d, J ) 5 Hz, POCH2CH3), 59.7 (d, J ) 7
Hz, POCH2CH3), 59.8 (d, J ) 5 Hz, POCH2CH3), 72.5 (d, J )
35 Hz, 3-CH), 76.8 (d, J ) 32 Hz, 1-CH), 96.5 (s, 2-CH),127.2
(dd, J ) 11, 6 Hz, 4-CH), 146.7 (dd, J ) 10, 3 Hz, 5-CH). 31P-
{1H} NMR (121.6 MHz, C6D6): δ 141.6 (t, J ) 47 Hz, 1P,
apical-P), 154.8 (dd, J ) 47, 43 Hz, 1P, equatorial-P), 156.0
(dd, J ) 47, 43 Hz, 1P, equatorial-P). HRMS (FAB): calcd for
2-, 3-, and 6-CH), 5.45 (t, J ) 9 Hz, 1H, 5-CH), 7.15-7.25 (m,
12H, PPh), 7.7-7.8 (m, 3H, PPh). 31P{1H} NMR (121.6 MHz,
C6D6): δ 168.6 (br dd, 40, 18 Hz, 1P), 169.3 (br dd, J ) 40, 18
Hz, 1P), 183.6 (br t, J ) 18 Hz, 1P).
Rea ction w ith P (OiP r )3. Reaction of complex 1 (17.2 mg,
0.0545 mmol) with P(OiPr)3 (40.0 µL, 0.162 mmol) in C6D6 at
50 °C for 20 h gave a mixture of Ru(6-η1:1,3-η3-COT){P(OiPr)3}3
(3e) and Ru(η4-1,3,5-COT){P(OiPr)3}3 (4e) in 8% and 48%
yields, respectively. These complexes were characterized spec-
troscopically by 1H-1H COSY and analogy of the related
complexes. Since resonances due to 3e in the 1H NMR
spectrum were significantly obscured by the signals due to 4e
and the yield of 3e was low, complex 3e failed to be character-
ized except the following resonances. 3e: δ 4.4 (m, 3H, 1-, 2-,
and 3-CH), 5.65 (m, 1H, 5-CH), 6.50 (dd, J ) 12, 5 Hz, 1H,
4-CH). 31P{1H} NMR (121.6 MHz, C6D6): δ 138.7 (t, J ) 43
Hz, apical-P), 153.0 (t, J ) 43 Hz, equatorial-P), 157.2 (t, J )
43 Hz, equatorial-P). 4e: 1H NMR (300.4 MHz, C6D6): δ 1.2-
1.5 (m, 18H, POCHMe2), 1.75 (br, 1H, 8-CH2), 2.0-2.4 (br, 3H,
8- and 7-CH2), 3.0 (br t, 1H, J ) 5 Hz, 4-CH), 3.2 (br, 1H,
1-CH), 4.7-5.1 (br, 11H, POCHMe2, 2- and 3-CH), 5.3 (m, 1H,
6-CH), 6.3 (t, J ) 10 Hz, 1H, 5-CH). 31P{1H} NMR (121.6 MHz,
C6D6): δ 147.9 (br d, J ) 38 Hz, 2P), 161.4 (br t, J ) 38 Hz,
1P).
C
26H55O9P3Ru 706.21, found 706.4236. Anal. Calcd for C26H55
-
O9P3Ru: C, 44.25; H, 7.86. Found: C, 44.02; H, 8.09.
(b) Complex 1 (22.7 mg, 0.0720 mmol) was reacted with
P(OEt)3 (40.0 µL, 0.233 mmol) in C6D6 and heated at 50 °C
for 24 h. A mixture of complex 3b and Ru(η4-1,3,5-COT)-
{P(OEt)3}3 (4b) was formed in 36% and 40% yields, respec-
tively. Complex 4b was characterized spectroscopically. 4b: 1H
NMR (300.4 MHz, C6D6): δ 1.1-1.3 (br, 27H, POCH2CH3), 1.2
(obscured by signals due to phosphite, 8-CH2), 1.74 (br, 1H,
8-CH2), 2.0 (m, 1H, 7-CH2), 2.4 (br, 1H, 7-CH2), 3.15 (t, J ) 8
Hz, 1H, 4-CH), 3.26 (m, 1H, 1-CH), 3.8-4.2 (br, 18H, POCH2-
CH3) 5.1-5.2 (m, 3H, 2-, 3-, 6-CH), 6.33 (t, J ) 9 Hz, 1H, 5-CH).
Rea ction w ith P (OMe)2P h . Complex 1 (22.6 mg, 0.0717
mmol) was reacted with P(OMe)2Ph (36.0 µL, 0.227 mmol) in
C6D6 and heated at 50 °C for 24 h. A mixture of Ru(η4-1,5-
COD)(η4-1,3,5-COT){P(OMe)2Ph} (2c), Ru(6-η1:1-3-η3-COT)-
{P(OMe)2Ph}3 (3c), and Ru(η4-1,3,5-COT){P(OMe)2Ph}3 (4c)
was obtained in 30%, 13%, and 61% yields, respectively. These
complexes were characterized spectroscopically, by use of 1H-
1H COSY and analogy of the related complexes. 2c: 1H NMR-
(300.4 MHz, C6D6): δ 0.87 (t, J ) 14 Hz, 1H), 1.6 (br, 1H), 1.8
(br, 1H), 2.0 (br, 2H), 2.2 (obscured by signal due to free 1,5-
COD), 2.37 (t, J ) 8 Hz, 1H, 8-CH2 in COT), 2.5 (m, 1H), 2.7
(m, 1H), 3.2-3.4 (obscured by signals due to 4c, POMe), 4.8
(obscured by signals due to 4c, COT), 4.98 (m, 1H, COT), 5.10
(t, J ) 8 Hz, 1H, COT), 5.2 (m, 1H, COT), 7.1-7.7 (m, 15H,
PPh). 3c: 31P{1H} NMR (121.6 MHz, C6D6): δ 187.3 (s). 4c:
1H NMR (300.4 MHz, C6D6): δ 0.19 (br t, J ) 12 Hz, 1H,
8-CH2), 1.4 (br, 1H, 8-CH2), 1.8 (m, 1H, 7-CH2) 2.1 (m, 1H,
7-CH2), 2.84 (br, 1H, 4-CH), 3.0 (m, 1H, 1-CH), 3.2-3.4 (m,
18H, POMe), 4.8-4.9 (m, 3H, 2-, 3-, 6-CH), 5.48 (t, J ) 9 Hz,
1H, 5-CH), 7.1-7.7 (m, 15H, PPh). 31P{1H} NMR (121.6 MHz,
C6D6): δ 174.0 (br, 1P), 174.4 (br, 1P), 189.4 (br, 1P).
Rea ction w ith P (OMe)P h 2. Reaction of complex 1 (21.3
mg, 0.0675 mmol) with P(OMe)Ph2 (41.0 µL, 0.204 mmol) in
C6D6 at 50 °C for 24 h gave a mixture of Ru(6-η1:1-3-η3-COT)-
{P(OMe)Ph2}3 (3f) and Ru(η4-1,3,5-COT){P(OMe)Ph2} (4f) in
17% and 53% yields, respectively. These complexes were
1
characterized spectroscopically by H-1H COSY and analogy
of the related complexes. 3f: 1H NMR (300.4 MHz, C6D6): δ
1.27 (br, 1H, 8-CH2), 1.7 (br, 8-CH2), 2.3 (obscured by impurity,
7-CH2), 3.5 (m, 1H, 6-CH), 3.80 (br, 1H, 3-CH), 4.43 (dt, J )
17, 9 Hz, 1H, 2-CH), 4.6 (br, 1H, 1-CH), 5.05 (m, 1H, 5-CH),
5.27 (br, 1H, 4-CH), 6.9-7.7 (m, 30H, PPh). 31P{1H} NMR
(121.6 MHz, C6D6): δ 126.6 (t, J ) 29 Hz, 1P), 143.9 (t, J ) 29
Hz, 1P), 144.8 (t, J ) 29 H, 1P). 4f: 1H NMR (300.4 MHz,
C6D6): δ 0.7 (br t, J ) 12 Hz, 8-CH2), 1.5 (obscured by impurity,
8-CH2), 1.78 (m, 1H, 7-CH2), 2.0 (br, 1H, 7-CH2), 2.6-3.0 (br,
11H, POMe, 4-CH, and 1-CH), 4.30 (br, 1H, 2-CH), 4.54 (t, J
) 8 Hz, 1H, 3-CH), 5.0 (m, 1H, 6-CH), 5.96 (t, J ) 10 Hz, 1H,
5-CH), 6.9-7.7 (m, 30H, PPh). 31P{1H} NMR (121.6 MHz,
C6D6): δ 140 (br, 2P), 152 (br, 1P).
Rea ction s w ith P (OEt)P h 2. (a) Reaction of complex 1
(154.5 mg, 0.490 mmol) with P(OEt)Ph2 (317.4 µL, 1.43 mmol)
in toluene at 50 °C for 24 h followed by workup and recrys-
tallization from a mixture of THF/hexane gave light yellow
powders of Ru(η4-1,3,5-COT){P(OEt)Ph2}3 (4g) in 42% yield
(199.7 mg, 0.208 mmol). 1H NMR (300.4 MHz, C6D6): δ 0.6
(br, 1H, 8-CH2), 0.9-1.3 (m, 10H, POCH2Me and 8-CH2), 1.9
(m, 1H, 7-CH2), 2.2 (obscured by impurity, 7-CH2), 2.7 (br, 2H,
1- and 4-CH), 2.9-3.4 (br, 6H, POCH2Me), 4.30 (br, 1H, 2-CH),
4.45 (br t, J ) 5 Hz, 1H, 3-CH), 5.0 (m, 1H, 6-CH), 5.95 (t, J
) 10 Hz, 1H, 5-CH), 7.0-7.9 (m, obscured by impurity, Ph).
31P{1H} NMR (121.6 MHz, C6D6): δ 164.0 (br, 2P), 174.8 (br,
1P).
(b) Reaction of 1 (8.9 mg, 0.028 mmol) with P(OEt)Ph2 (18.3
µL, 0.0847 mmol) in benzene-d6 (0.6 mL) at 50 °C gave Ru-
(η4-1,5-COD)(η4-1,3,5-COT){P(OEt)Ph2} (2g) in 89% within 10
min, and 2g was then converted to a mixture of 3g and 4g in
16% and 52% yields, respectively, at 50 °C for 25 h. The 1H
NMR signals due to 3g were significantly overlapped with
signals of other complexes but estimated by COSY. 2g: 1H
NMR (300.4 MHz, C6D6): δ 0.87 (br, 1H, COT), 0.93 (t, J ) 6
Hz, 3H, POCH2Me), 1.5-2.5 (m, COD and COT, 13H), 2.6 (m,
1H, COT), 3.1 (m, 1H, COT), 3.2-3.5 (m, 4H, COD), 3.8
(obscured by free P(OEt)Ph2, POCH2Ph), 4.92 (t, J ) 8 Hz,
2H, COT), 5.13 (t, J ) 8 Hz, 1H, COT), 5.38 (t, J ) 8 Hz, 1H,
COT), 7.0-7.2 (obscured by free P(OEt)Ph2), 7.59 (m, 4H, PPh),
7.83 (t, J ) 7 Hz, 2H, PPh). 31P{1H} NMR (121.6 MHz, C6D6):
δ 151.4 (s, 1P). 3g: 1H NMR (300.4 MHz, C6D6): δ 1.7 (7-CH2),
Rea ction w ith P (OEt)2P h . Reaction of complex 1 (21.2 mg,
0.0672 mmol) with P(OEt)2Ph (40.0 µL, 0.208 mmol) in C6D6
at 50 °C for 24 h gave a mixture of Ru(6-η1:1-3-η3-COT)-
{P(OEt)2Ph}3 (3d ) and Ru(η4-1,3,5-COT){P(OEt)2Ph}3 (4d ) in
11% and 77% yields, respectively. These complexes were
1
characterized spectroscopically by H-1H COSY and analogy
of the related complexes. Since resonances due to 3d in the
1H NMR spectrum were significantly obscured by the signals
due to 4d and the yield of 3d was low, complex 3d was
characterized by the 31P{1H} NMR spectrum. 3d : 31P{1H}
NMR (121.6 MHz, C6D6): δ 159.3 (t, J ) 37 Hz, 1P, apical-P),
173.3 (dd, J ) 37, 25 Hz, 1P, equatorial-P), 175.8 (dd, J ) 37,
25 Hz, 1P, apical-P). 4d : 0.25 (br t, J ) 10 Hz, 1H, 8-CH2),
1.2 (m, 18H, POCH2Me), 1.3 (br, 1H, 8-CH2), 1.75 (m, 1H,
7-CH2), 2.1 (m, 1H, 7-CH2), 2.8 (m, 1H, 4-CH), 2.95 (q, J )
7H, 1H, 1-CH), 3.5-4.0 (m, 12H, POCH2Me), 4.8-5.0 (m, 3H,

Reaction of Ru(η4-1,5-COD)(η6-1,3,5-COT)
Organometallics, Vol. 22, No. 12, 2003 2385
1.9 (7-CH2), 2.3 (6-CH), 3.4 (8-CH2), 4.3 (br, 1H, 3-CH), 4.7 (t,
J ) 9 Hz, 1H, 2-CH), 4.9 (br, 1H, 1-CH), 5.6 (4- and 5-CH).
31P NMR (121.6 MHz, C6D6): δ 149.3 (br, 1P), 167.9 (br, 2P).
Calcd for C21H31NRu: C, 63.28; H, 7.84; N, 3.52. Found: C,
63.29; H, 8.10; N, 3.54.
(b) Treatment of 1 (91.3 mg, 0.289 mmol) with tert-butyl-
isonitrile (100.0 µL, 0.884 mmol) in a Schlenk tube at 50 °C
for 4 h followed by removal of volatile materials gave a white
powder. Extraction of the white powder by hexane, which was
stored in a deep freezer, led to crystallization of off-yellow
crystals of Ru(η4-1,5-COD)(CNtBu)3 (5j) in 17% yield (22.4 mg,
Rea ction s w ith P (OP h )3. (a) Complex 1 (171.5 mg, 0.544
mmol) was dissolved in hexane (4 mL) into which P(OPh)3
(570.6 µL, 2.177 mmol) was added by a hypodermic syringe,
and then the reaction mixture was stirred at 50 °C for 17 h,
during which a white precipitate was deposited. The solvent
was removed by a cannula, and the white precipitate was
washed with cold hexane to give a 2:1 mixture of Ru(6-η1:1-
3-η3-COT){P(OPh)3}3 (3h ) and Ru(η4-1,5-COD){P(OPh)3}3 (5h )
(determined by 1H NMR) as an analytically pure white powder
in 3% yield (18.0 mg, 0.0158 mmol). The NMR spectrum was
characterized by 1H-1H COSY and analogy of the related
compounds. 3h : 1H NMR (300.4 MHz, C6D6): δ 0.87 (dt, J )
12, 5 Hz, 1H, 7-CH2), 1.51 (m, 1H, 8-CH2), 2.2 (obscured by
the signal due to 3c, 8-CH2), 2.78 (m, 1H, 7-CH2), 3.28 (m,
1H, 6-CH), 4.3 (br, 1H, 3-CH), 4.7 (br, 1H, 1-CH), 4.95 (dt, J
) 17, 8 Hz, 2-CH), 5.46 (br, 1H, 4-CH), 5.56 (m, 1H, 5-CH),
6.8-7.3 (m, obscured by the signals due to 5h ). 31P{1H} NMR
(121.6 MHz, C6D6): δ 127.8 (dd, J ) 45, 44 Hz, 1P, axial-P),
144.0 (dd, J ) 47, 45 Hz, 1P, equatorial-P), 146.2 (dd, J ) 47,
44 Hz, 1P, equatorial-P). 5h : 1H NMR (300.4 MHz, C6D6): δ
2.21 (br, 4H, CH2 in COD), 2.35 (br, 4H, CH2 in COD), 4.02
(br s, 4H, CHd in COD), 6.8-7.3 (m, obscured by the signals
due to 3h ). 31P{1H} NMR (121.6 MHz, C6D6): δ 144.8 (s). Anal.
Calcd for C186H167O27P9Ru3 (as a 2:1 mixture of 3h and 5h ):
C, 65.39; H, 4.93. Found: C, 65.14; H, 4.73.
1
0.0448 mmol). The H NMR spectrum of 5j was characterized
1
by H-1H COSY. H NMR (300.4 MHz, C6D6): δ 1.17 (s, 27H,
CNtBu), 2.7 (m, 4H, endo- or exo-CH2 in COD), 2.9 (m, 4H,
exo- and endo-CH2 in COD), 3.8 (m, 4H, dCH in COD). 13C-
{1H} NMR (75.5 MHz, C6D6): δ 31.3 (s, CMe3), 35.4 (s, CH2 in
COD), 55.5 (s, CMe3), 69.8 (s, CH in COD), 178.7 (s, CNtBu).
IR (KBr, cm-1): 2972 (w), 2923 (w), 2862 (w), 2796 (w), 2126
(vs), 2102 (vs), 1847 (vs), 1457 (m), 1364 (m), 1212 (s). Anal.
Calcd for C23H39N3Ru: C, 60,23; H, 8.57; N, 9.16. Found: C,
59.44; H, 8.83; N, 8.98.
(c) Complex 1 (18.3 mg, 0.0580 mmol) was placed in an NMR
tube into which C6D6 (0.6 mL) was introduced by bulb-to-bulb
distillation. Three equivalents of tert-butylisonitrile (20.0 µL,
0.177 mmol) was added by a hypodermic syringe through the
rubber septum. Quantitative formation of 2j was confirmed
by 15 min at room temperature by NMR spectrum. The
reaction mixture was heated at 50 °C for 2.5 h to give 5j in
58% yield, where liberation of 1,5-COD (10%) and 1,3,5-COT
(38%) were observed. Further treatment of the reaction
mixture at 50 °C for 23 h gave Ru(6-η1:1-3-η3-COT)(CNtBu)3
(3j), where amounts of liberated 1,5-COD and 1,3,5-COT were
estimated to be 92% and 25% yields, respectively, based on 1.
3j: 1H NMR (300.4 MHz, C6D6): δ 0.87 (s, 9H, apical-CNtBu),
1.19 (s, 9H, equatorial-CNtBu), 1.21 (s, 9H, equatorial-CNtBu),
2.2 (m, 2H, 7- and 8-CH2), 2.7 (m, 1H, 6-CH). 2.8 (m, 2H, 7-
and 8-CH2), 4.59 (t, J ) 7.5 Hz, 1H, 2-CH), 4.75 (dd, J ) 8, 4
Hz, 1H, 3-CH), 4.96 (td, J ) 8, 4 Hz, 1H, 1-CH), 5.92 (dd, J )
7, 4 Hz, 1H, 5-CH), 6.04 (dd, J ) 7, 4 Hz, 1H, 4-CH).
(b) Complex 1 (112.0 mg, 0.3551 mmol) was dissolved in
hexane (5 mL) into which P(OPh)3 (279.2 µL, 1.065 mmol) was
added, and then the reaction mixture was warmed at 50 °C
for 40 h. After removal of all volatile matters, the resulting
white solid was recrystallized from a mixture of benzene/
hexane (2 mL/1 mL), giving a white powder of Ru{P(OC6H4)-
(OPh)2}2{P(OPh)3}2 (6h ) in 8% yield (36.8 mg, 0.0275 mmol).
1H NMR (300.4 MHz, CDCl3): δ 6-9 (m, POPh and POC6H4).
31P{1H} NMR (121.6 MHz, CDCl3): δ 121.08 (ddd, J ) 691,
62, 54 Hz, 1P, axial-P), 128.53 (ddd, J ) 54, 42, 36 Hz, 1P,
equatorial-P), 153.93 (ddd, J ) 691, 54, 42 Hz, 1P, axial-P),
156.39 (ddd, J ) 6, 54, 36 Hz, 1P, equatorial-P). Anal. Calcd
for C72H58O12P4Ru: C, 64.52; H, 4.36. Found; 64.09; H, 4.42.
(d) Complex 5j (9.3 mg, 0.020 mmol) was placed in an NMR
tube into which C6D6 (0.6 mL) and then 2 equiv of 1,3,5-COT
(5.2 µL, 0.041 mmol) were introduced. The reaction mixture
was warmed at 50 °C, and the time courses of the reaction
were periodically monitored by 1H NMR. Complex 5j com-
pletely disappeared by 7 h, and 3j was produced in 54% yield.
(e) Isolated complex 5j (8.8 mg, 0.028 mmol) was placed in
an NMR tube into which C6D6 (0.6 mL) and then 10 equiv
excess of tert-butylisonitrile (31.5 µL, 0.279 mmol) were added.
The reaction mixture was warmed at 70 °C for 2 days to give
a light yellow solution of 7 in 55% yield with concomitant
Rea ction w ith P (OC6H4Cl-4)3. Treatment of complex 1
(22.7 mg, 0.0720 mmol) with P(OC6H4Cl-4)3 (115.5 mg, 0.2793
mmol) in benzene at 50 °C for 2.5 h followed by workup gave
Ru{P(OC6H3Cl-4)(OC6H4Cl-4)2}2{P(OC6H4Cl-4)3}2 (6i) in 41%
1
1
yield (51.5 mg, 0.0294 mmol). H NMR (300.4 MHz, C6D6): δ
formation of 1,5-COD (91%) and unidentified precipitate. H
6.5-7.0 (m, aromatic). 31P{1H} NMR (121.6 MHz, C6D6): δ
121.7 (ddd, J ) 690, 58, 54 Hz, 1P, axial-P), 129.2 (ddd, J )
54, 42, 36 Hz, 1P, equatorial-P), 154.4 (ddd, J ) 690, 54, 42
Hz, 1P, axial-P), 156.7 (ddd, J ) 58, 54, 36 Hz, 1P, equatorial-
P).
NMR (300.4 MHz, C6D6): δ 1.21 (s).
(f) Complex 1 (92.5 mg 0.293 mmol) was dissolved in toluene
(ca. 3 mL) into which tert-butylisonitrile (620 µL, 5.48 mmol)
was added. The reaction mixture was stirred at 50 °C for 55
h, and then all volatile materials were removed under reduced
pressure. The resulting solid was extracted with a mixture of
acetone and hexane, and fractional crystallization of the
solution gave light yellow crystals. Although instability of the
crystals prevented a detailed analysis, it was characterized
as a homoleptic isonitrile complex, Ru(CNtBu)5 (7), on the basis
of the following data, and the yield was estimated as 32% (48.0
Rea ction s w ith CNtBu . (a) An equimolar amount of tert-
butylisonitrile (33.3 µL, 0.295 mmol) was added into a hexane
solution (5 mL) of 1 (93.0 mg, 0.295 mmol), and the solution
was stirred at room temperature for 2 h. All volatile materials
were removed under vacuum, and the resulting solid was
recrystallized from cold hexane to give pale yellow needles of
Ru(η4-1,5-COD)(η4-1,3,5-COT)(CNtBu) (2j) in 26% yield (30.1
mg, 0.0755 mmol). Since quantitative formation of 2j was
shown by NMR study, the low yield is due to difficulty of
1
mg, 0.0931 mmol). H NMR (300.4 MHz, C6D6): δ 1.21(s). IR
(KBr, cm-1): 2981 (m), 2937 (w), 2211 (sh), 2154 (vs), 2116
(s), 1637 (w), 1459 (w), 1372 (w), 1236 (sh), 1200 (m), 553 (m).
Rea ction s w ith CO. (a) Complex 1 (24.1 mg, 0.0716 mmol)
was placed in an NMR tube into which C6D6 (0.6 mL) was
introduced by bulb-to-bulb distillation. Then, CO (0.1 MPa)
was introduced into the NMR tube. After 16 h at room
temperature, Ru(η4-1,5-COD)(η4-1,3,5-COT)(CO) (2k ) was ob-
tained in 97% yield. Complex 2k was characterized by analogy
of related complexes. 1H NMR (300.4 MHz, C6D6): δ 1.47 (t, J
) 8 Hz, 1H, 8-CH2 in COT), 1.8-1.9 (m, 10H, 7-CH2 in COT
and CH2 in COD), 2.3 (t, J ) 8 Hz, 1H, 8-CH in COT), 2.4 (br
1
manipulation. The H NMR spectrum of 2j was characterized
1
by H-1H COSY and analogy of related complexes as well as
elemental analysis. 1H NMR (300.4 MHz, C6D6): δ 1.22 (s, 9H,
CNtBu), 1.38 (t, J ) 12 Hz, 1H, 8-CH2 in COT), 2.0-2.2 (m,
11H, 7- and 8-CH2 in COT, CH2 in COD), 2.36 (br t, J ) 7 Hz,
1H, 4-CH), 2.4 (br, 1H, 1-CH), 2.6 (br m, 4H, CH2 in COD),
3.19 (m, 1H, CH in COD), 3.52 (m, 1H, CH in COD), 5.02 (m,
2H, 2- and 3-CH), 5.13 (t, J ) 6 Hz, 1H, 6-CH), 6.02 (dd, J )
6, 6 Hz, 1H, 5-CH). IR (KBr, cm-1): 2120 (vs), 1641 (w). Anal.

2386 Organometallics, Vol. 22, No. 12, 2003
Hirano et al.
Ta ble 3. Cr ysta llogr a p h ic a n d P h ysica l Da ta for
t, J ) 7 Hz, 1H, 4-CH in COT), 2.6 (m, 1H, 1-CH in COT), 3.3
(m, 2H in COD), 3.7 (m, 2H, CH in COD), 4.81 (dd, J ) 7, 6
Hz, 1H, 3-CH in COT), 4.96 (dd, J ) 7, 6 Hz, 1H, 2-CH in
COT), 5.07 (dt, J ) 11, 7 Hz, 1H, 6-CH in COT), 6.12 (dd, J )
11, 8 Hz, 1H, 5-CH in COT). Complexes 3k and 5k were
characterized spectroscopically by use of 1H-1H COSY and
analogy of related compounds. 3k : 1H NMR (300.4 MHz,
C6D6): δ 1.64 (td, J ) 8, 6 Hz, 1H, 8-CH2 in COT), 1.7 (m, 1H,
7-CH in COT), 1.9 (partly obscured by signals due to 5k , 8-CH2
in COT), 2.2 (obscured by signals due to 5k , 7-CH2), 2.7 (br,
1H, 7-CH2 in COT), 3.87 (t, J ) 8 Hz, 1H, 2-CH in COT), 4.57
(m, 1H, 3-CH in COT), 4.79 (td, J ) 8, 5 Hz, 1-CH in COT),
5.29 (t, J ) 4 Hz, 2H, 5- and 4-CH in COT). 5k : 1H (300.4
MHz, C6D6): δ 1.9 (m, 4H, CH2 in COD), 2.1 (m, 4H, CH2 in
COD), 3.8 (m, 4H, CH in COD).
(b) Complex 1 (100 mg, 0.317 mmol) was placed in a 200
mL Schlenk tube into which hexane (ca. 4 mL) was added
under nitrogen atmosphere. After evacuation of the system
by freeze-pump-thaw cycles, CO (0.1 MPa) was introduced
into the system and stirred at 50 °C for 20 days to give an
orange precipitate of Ru3(CO)12 in 44% yield/Ru (30 mg, 0.047
mmol). IR (hexane, cm-1): 2072 (s), 2061 (s), 2038 (s), 1995
(vs), 1960 (w).
Rea ction w ith NEt3. Complex 1 (14.2 mg, 0.045 mmol) was
placed in an NMR tube into which benzene-d6 (ca. 0.6 mL)
was added by vacuum distillation. The NMR tube was capped
with a rubber septum under nitrogen atmosphere, and then
NEt3 (19 µL, 0.14 mmol) was injected into the NMR tube by
use of a hypodermic syringe. The reaction system was warmed
at 50 °C for 3 days, during which the reaction course was
periodically monitored by NMR. The NMR data show that
complex 1 remained unreacted under these conditions. Simi-
larly, neither pyridine nor DMAP reacted with 1 at all under
these conditions.
X-r a y An a lysis of 5j. A selected crystal of complex 5j
obtained by recrystallization from cold acetone was mounted
on top of a glass capillary by using paraton-N oil. The
crystallographic data and experimental details are sum-
marized in Table 3.
Ru (η4-1,5-COD)(CNtBu )3 (5j)
formula
fw
C23H39N3Ru
458.65
cryst color
yellow
habit
cryst size, mm
cryst syst
space group
a, Å
b Å
c, Å
prismatic
0.70 × 0.5 × 0.3
monoclinic
C2/c (No. 15)
29.030(6)
9.726(6)
19.438(6)
116.96(2)
4891(3)
8
â, deg
V, Å3
Z
D(calcd), g cm-3
data collection temp, K
scan mode
1.25
200 ( 1
ω-2θ
scan width, deg
scan speed, deg min-1
2θmax
1.73 + 30.30 tan θ
32.0
55.0
6066
0.085
3793
245
15.48
0.070
no. of measd reflnsa
Rint
no. of obsd reflnsb
no. of params refined
reflection/param ratio
Rc
c
Rw
0.090
0.90
GOFd
a
b
Total. I > 3.00σ(I). c R ) ∑||Fo| - |Fc||/∑|Fo|; Rw ) [∑w(|Fo|
- |Fc|)2/∑w|Fo| ]0.5
.
Goodness of fit.
2
d
Ack n ow led gm en t. The authors thank Ms. S. Kiyota
for elemental analyses. This work was financially sup-
ported by the Proposal-based New Industry Creative
Type Technology R&D Promotion Program from New
Energy and Industrial Technology Development Orga-
nization (NEDO) of J apan and a Grant-in-Aid for
Scientific Research from the Ministry of Education,
Sports, Culture, Science and Technology, J apan.
The measurement was made on a Rigaku RASA-7R diffrac-
tometer with graphite-monochromated Mo KR radiation (λ )
0.71069 Å) and a rotating anode generator. The reflection
intensities were monitored by three standard reflections at
every 150 measurements. No decay correction was applied.
Reflection data were corrected by psi-scan methods. The
structure was solved by direct methods, SIR9236 full-matrix
least-squares calculations. All atoms except hydrogen atoms
were found and were solved anisotropically. These calculations
were performed on a Silicon Graphics O2 workstation using
the program system teXsan.37
Su p p or tin g In for m a tion Ava ila ble: Tables of atomic
coordinates, atomic displacement parameters, and bond dis-
tances and angles for 5j. This material is available free of
charge via the Internet at http://pubs.acs.org.
OM030064T
(36) SIR92: Altomare, A.; Burla, M. C.; Camalli, M.; Cascarano, M.;
Giacovazzo, C.; Guagliardi, A.; Polidori, G. J . Appl. Crystallogr. 1994,
27, 435.
(37) teXsan: Crystal Structure Analysis Package; Molecular Struc-
ture Corporation: The Woodlands, TX, 1985 and 1992.
(35) (a) Cope, A. C.; Haven, A. C. J r.; Ramp, F. L.; Trumbull, E. R.
J . Am. Chem. Soc. 1952, 74, 4867. (b) Organic Synthesis; Vol. 73, p
240.