Cyclopropenation and related reactions of ruthenium vinylidene complexes

Article abstract of DOI:10.1021/ja960001k

Facile deprotonation of a number of cationic ruthenium vinylidene complexes, followed by cyclopropenation, is accomplished in acetone. The deprotonation of [Ru]=C=(Ph)CH₂R⁺, ([Ru] = (η⁵-C₅H₅)(PPh₃)₂Ru) by n-Bu₄NOH induces a novel cyclization reaction and yields the neutral cyclopropenyl complexes [Ru]-C=C(Ph)CHR (3b, R = CN; 3c, R = Ph; 3d, R = CH=CH₂; 3e, R = CH=CMe₂). Complex [Ru]-C=C(C₆H₉)CHCN⁺ (3k) is similarly prepared. Protonation of 3b-3e regenerates the corresponding vinylidene complexes. Deprotonation of [Ru]=C=C(Ph)CH₂COOMe⁺ (2h) by n-Bu₄NOH induces a different type of cyclization and yields the neutral furan complex [Ru]-C=C(Ph)CH=C(O)OMe (4h). The cyclopropenyl complex containing a methoxy substituent cannot be prepared from [Ru]=C=C(Ph)CH₂OCH₃⁺ (2i), but F^- of n-Bu₄NF attacks the C(α) of 2i to produce the unstable vinyl complex [Ru]C(F)=C(Ph)CH₂OCH₃ (5). Complex [Ru]-C=C(Ph)C(CN)OCH₃ (9b) was indirectly prepared from the addition of TCNQ to 3b, giving [Ru]=C=C(Ph)CH(CN)TCNQ (6b) followed by methanolysis. Unlike 3, complex 9b is not converted to vinylidene complex, instead, removal of the methoxy substituent by acid gives the cationic cyclopropenylium complex [Ru]-C=C(Ph)G(GN)⁺ (10b). Complex [Ru]-C=C(Ph)C(COOMe)⁺ (10h) is similarly prepared from 4h via a TCNQ complex 6h followed by a methoxy-substituted complex 9h. In the presence of allyl iodide, opening of the three-membered ring of 3b, followed by a subsequent oxidative coupling reaction, gives a dimeric dicationic product {[Ru]=C=C(Ph)-CHCN}₂²⁺ (11). Proton abstraction of 11 by n-Bu₄-NF gives the biscyclopropenyl complex {[Ru]-C=C(Ph)CCN}₂ (12). Molecular structures of complexes 3b, 3f, 4h, 6b, 9b, and 11 have been confirmed by X-ray diffraction analysis.

Full text of DOI:10.1021/ja960001k

J. Am. Chem. Soc. 1996, 118, 6433-6444
6433
Cyclopropenation and Related Reactions of Ruthenium
Vinylidene Complexes
Pei-Chen Ting, Ying-Chih Lin,* Gene-Hsiang Lee, Ming-Chu Cheng, and Yu Wang
Contribution from the Department of Chemistry, National Taiwan UniVersity,
Taipei, Taiwan 106, Republic of China
ReceiVed January 2, 1996X
Abstract: Facile deprotonation of a number of cationic ruthenium vinylidene complexes, followed by cyclopropenation,
is accomplished in acetone. The deprotonation of [Ru]dCd(Ph)CH2R+, ([Ru] ) (η5-C5H5)(PPh3)2Ru) by n-Bu4-
NOH induces a novel cyclization reaction and yields the neutral cyclopropenyl complexes [Ru]-CdC(Ph)CHR
(3b, R ) CN; 3c, R ) Ph; 3d, R ) CHdCH2; 3e, R ) CHdCMe2). Complex [Ru]-CdC(C6H9)CHCN+ (3k) is
similarly prepared. Protonation of 3b-3e regenerates the corresponding vinylidene complexes. Deprotonation of
[Ru]dCdC(Ph)CH2COOMe+ (2h) by n-Bu4NOH induces a different type of cyclization and yields the neutral furan
complex [Ru]-CdC(Ph)CHdC(O)OMe (4h). The cyclopropenyl complex containing a methoxy substituent cannot
+
be prepared from [Ru]dCdC(Ph)CH2OCH3 (2i), but F- of n-Bu4NF attacks the CR of 2i to produce the unstable
vinyl complex [Ru]C(F)dC(Ph)CH2OCH3 (5). Complex [Ru]-CdC(Ph)C(CN)OCH3 (9b) was indirectly prepared
from the addition of TCNQ to 3b, giving [Ru]dCdC(Ph)CH(CN)TCNQ (6b) followed by methanolysis. Unlike 3,
complex 9b is not converted to vinylidene complex, instead, removal of the methoxy substituent by acid gives the
cationic cyclopropenylium complex [Ru]-CdC(Ph)C(CN)+ (10b). Complex [Ru]-CdC(Ph)C(COOMe)+ (10h)
is similarly prepared from 4h via a TCNQ complex 6h followed by a methoxy-substituted complex 9h. In the
presence of allyl iodide, opening of the three-membered ring of 3b, followed by a subsequent oxidative coupling
reaction, gives a dimeric dicationic product {[Ru]dCdC(Ph)-CHCN}22+ (11). Proton abstraction of 11 by n-Bu4-
NF gives the biscyclopropenyl complex {[Ru]-CdC(Ph)CCN}2 (12). Molecular structures of complexes 3b, 3f,
4h, 6b, 9b, and 11 have been confirmed by X-ray diffraction analysis.
Introduction
mixtures of 1,3-dienes, allenes, and acetylenes are formed.8 This
strongly suggests that the formation of acetylenes involves
vinylidenes as intermediates.9 Some theoretical results also
suggest that the acetylenic products are formed from vinylidene
produced through bond breaking and hydrogen shift.10,11 It thus
appears that vinylidene is an important intermediate in the
thermal rearrangement of cyclopropene to acetylene.12 How-
ever, organic vinylidene (R2CdC:) is thermodynamically un-
stable and evidence for its existence has been derived mostly
from the reaction products. Fortunately, vinylidene, among a
variety of reactive organic species that can be stabilized by
complex formation with transition metals, has been shown to
form a plethora of stable organometallic compounds. Particu-
Cyclopropene is believed to be the most highly strained
cycloalkene, with the estimated substantial strain energy of more
than 50 kcal/mol.1 This molecule has hence been under intense
investigation2 and has played a crucial role in the development
of important concepts such as aromaticity and chemical reac-
tivities.3 Three general methods are known for the synthesis
of cyclopropenes:4 viz., addition of carbene to alkyne,5 ring
closure of vinylcarbene,6 and 1,2-elimination of a suitable
precursor such as halocyclopropane.7 Two recent papers2a,b have
suggested vinylidene (alkylidenecarbene) to be the intermediate
in the thermal rearrangement of cyclopropene: i.e. when
substituted cyclopropenes are heated or irradiated, complex
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X Abstract published in AdVance ACS Abstracts, June 15, 1996.
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S0002-7863(96)00001-7 CCC: $12.00 © 1996 American Chemical Society

6434 J. Am. Chem. Soc., Vol. 118, No. 27, 1996
Ting et al.
larly the mononuclear ruthenium(II) moieties, CpRu(PR3)2+ (Cp
) η5-C5H5), play an important role in the stabilization of
[Ru]dCdCRR′ derivatives.
Most surprisingly, with such a background, the relation
between vinylidene and cyclopropene in the organometallic
system has been mostly left unnoticed. We believed that
electron-withdrawing functionality, such as the CN group, at
Cγ might play a role in enhancing the acidity of its neighboring
proton. Thus an intramolecular cycloaddition leading to the
formation of the cyclopropenyl complex may be effected by a
base. We have reported our preliminary results on one specific
compound in a recent communication.22 After thorough ex-
ploration, it has been observed that the method indeed leads to
a number of cyclopropenyl complexes. Utilizing the above-
mentioned reactivities, herein we report the unprecedented
cyclopropenation reaction of the vinylidene ligands with various
substituents at Cγ and limitations of this type of reaction. In
addition, a coupling reaction of the cyclopropenyl complex
leading to the synthesis of the first 2,2′-bicyclopropenyl metal
complex is also reported.
Metal vinylidene complexes have also attracted a great deal
of attention since they offer the possibility of development of
new types of organometallic intermediates that may have
unusual reactivity. Extensive reviews on this subject have
appeared recently.13 The best entry into the transition metal
vinylidene complexes is the addition of electrophiles to the
electron-rich carbon of metal alkynyl complexes.14 A theoretical
study of the vinylidene complex has revealed the localization
of electron density on Câ (HOMO) or the MdC double bond
and electron deficiency at CR.15 Thus the MdC double bond
and the Câ atom are more susceptible to electrophilic attack
whereas the CR atom is prone to nucleophilic attack.16 Hence
the reactions of such compounds containing electron-rich metals
with electrophiles lead to formation of carbene complexes.17
On the other hand, their reactions with nucleophiles generally
result in the formation of vinyl derivatives. Protonation of
vinylidene ligand at Câ is known to readily form a carbyne
unless the ligand is present in a cationic form. With a more
electron rich metal center, addition to the MdC bond yields an
η2-allene- or heteroketene-metal complex.18,19 Addition of
the acetylenic alcohols HCtC(CH2)nOH to CpRuL2Cl also
affords cyclic carbene complexes. The reaction proceeds via
initial formation of the vinylidene complexes, followed by an
intramolecular attack of the terminal alcohol function on CR.20
A study of the reaction of alcohols with Ru vinylidene
complexes has shown that the electron-withdrawing groups on
the acetylide unit or on the metal facilitate nucleophilic attack
at CR.21
Results and Discussion
Metal Vinylidene Complexes. Treatment of [Ru]-CtC-
Ph (1a) with ICH2CN affords the cationic vinylidene complex
[Ru]dCdC(Ph)CH2CN+ (2b) with 72% yield. Similarly,
preparations of complexes [Ru]dCdC(Ph)CH2R+ (2a, R ) H;
2c, R ) Ph; 2d, R ) CHdCH2; 2e, R ) CHdCMe2; 2h, R )
COOCH3; 2i, R ) COOC2H5; 2j, R ) OCH3) have all been
achieved with high yields. The complex [Ru]dCdC(C6H9)CH2-
CN+ (2k, C6H9 ) 1-cyclohexenyl) is also prepared from the
reaction of [Ru]-CtC-C6H9 with ICH2CN. With the excep-
tions of 2h and 2i, the vinylidene complexes mentioned above
have been prepared in CH2Cl2 either at room temperature or at
refluxing temperature. For the synthesis of 2h and 2i, a mixture
of CH2Cl2/CHCl3 (1:1 v/v) was used as solvent due to the
necessity of achieving higher reaction temperature. The most
characteristic spectroscopic data of these vinylidene complexes
consist of strongly deshielded CR resonance as a triplet at δ
340 ( 5 in the 13C NMR spectrum and a single 31P NMR
resonance normally at around δ 42 ( 1 in CDCl3 at room
temperature, which is due to the fluxional behavior of the
vinylidene ligand.23
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Deprotonation/Cyclopropenation of Vinylidene Com-
plexes. Deprotonation of 2b by n-Bu4NOH induces a new
cyclization reaction and yields a neutral cyclopropenyl complex
[Ru]-CdC(Ph)CHCN (3b) (Scheme 1). This reaction occurs
only in acetone. The light-orange-yellow crystalline precipitate
forms directly in the reaction mixture and can be obtained in
analytically pure form by a simple filtration. No cyclopropena-
tion reaction is observed in CH3CN or MeOH. When the
reaction is carried out at lower concentration, single crystals of
3b, suitable for X-ray diffraction analysis, are directly obtained.
Reaction of 2b with n-Bu4NF (1 M in THF) or DBU (1,8-
diazabicyclo[5.4.0]undecene) or KOH (dissolved in a minimum
amount of H2O) also yields 3b. Complex 3b is stable in air
and soluble in CH2Cl2, CHCl3, and THF but insoluble in diethyl
ether, n-hexane, MeOH, and CH3CN.
The 31P NMR spectrum of 3b displays resonances with the
2
expected two doublets pattern (δ 49.7 and 51.6 with JP-P
)
34.6 Hz) arising from the asymmetric three-membered ring. In
the 1H NMR spetrum of 3b, the resonance of the methyne proton
appears at δ 1.40, and in the 13C{1H} NMR spectrum, a triplet
at δ 126.2 with 2JC-P ) 23.5 Hz is assigned to the ruthenium-
bonded CR carbon.
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Cyclopropenation of Ruthenium Vinylidene Complexes
J. Am. Chem. Soc., Vol. 118, No. 27, 1996 6435
Scheme 1
Scheme 2
The deprotonation/cyclopropenation in acetone is a general
reaction for a number of vinylidene complexes, namely, similar
reactions are also known to occur for 2c, 2d, and 2e, giving
plexes,28 are also known. The acidity of the aliphatic protons
on a coordinated dppe ligand in a cationic iron vinylidene
complex29 has been employed for inducing the intramolecular
cyclization between the dppe and vinylidene ligand.
[Ru]-CdC(Ph)CHR (3c, R ) Ph; 3d, R ) CHdCH2; 3e, R )
CHdCMe2), respectively. Unlike 3b, complexes 3c-e can be
obtained only by using n-Bu4NOH as proton abstractor and the
reactions generally take longer. Complexes 3b-e are stable in
THF, but in CHCl3 compounds 3c, 3d, and 3e are less stable
than 3b. Furthermore, 3c decomposes in CDCl3 producing
Cp(PPh3)2RuCl and some unidentified organic products. De-
composition of 3d and 3e produces a complicated mixture. The
stability of the cyclopropenyl complexes in CHCl3 follows the
Electrophilic Additions of Ruthenium Cyclopropenyl
Complexes 3. Additions of CF3COOH to 3b-e regenerate 2b-
e, respectively, indicating the basic character of the methyne
carbon of the three-membered ring. Furthermore, 3k was
converted to 2k in MeOH indicating even stronger basicity. This
protonation is different from the acid-induced demethoxylation
of the iron cyclopropenyl complex.26 Attempts to remove
hydrogen bonded to the three-membered ring using Ph3C+
yielded an unexpected product. Treatment of 3b with Ph3C+
affords {[Ru]dCdC(Ph)CH(CPh3)CN}+ (2f) with 64% yield.
In this reaction, 2b is also isolated as a minor product (yield
<30%, probably due to contamination of HPF6 in Ph3CPF6).
Although Ph3C+ is commonly used as a hydride abstraction
reagent,30 as is evident from its reaction with several organic
cyclopropenyl compounds,31 it however serves as an electrophile
in the reaction with 3b. There are a few examples in the
literature in which electrophilic addition of Ph3C+ resulted in
the formation of the C-C bond.32
trend for the substituents of CN > Ph > CHdCH2
>
CHdCMe2. The phenyl group on the Cγ is not essential since
deprotonation of 2k also gives [Ru]-CdC(C6H9)CHCN (3k),
which exhibits better solubility in common organic solvents.
Facile deprotonation indicates the acidic nature of the methylene
protons of 2b-2e and 2k, which may be ascribed to the
combined effect of the cationic character, the electron-
withdrawing substituent, and the benzylic/allylic property of the
vinylidene complexes. 2a is inert toward n-Bu4NOH in acetone
probably due to the lack of this acidic proton. It also appears
that the hybridization of the Cδ should either be sp or sp2 for
the cyclopropenation to occur. However, the vinylidene com-
plex with a propargyl substituent at Câ is too reactive to yield
any isolable product. This is probably due to the presence of
the acidic proton that complicates the outcome. When treated
with nucleophiles, 2b fails to produce the intermolecular addition
product.24
Synthesis of metal cyclopropenyl derivatives in which the
metal bonds to C(sp3) of the cyclopropene ring (in this case the
three-membered ring can be viewed as an antiaromatic cyclo-
propenide ion) has been reported in the literature.25 However,
to our knowledge, only one example of such a derivative in
which the metal is bonded to the C(sp2) of the three-membered
ring has been reported.26 A few structurally different transition
metal cyclopropenylidene complexes, mostly prepared from
dichlorocyclopropene27 and a number of π-cyclopropene com-
Further deprotonation of the methyne proton of 2f by n-Bu4-
NF also affords [Ru]-CdC(Ph)C(CPh3)CN (3f) (Scheme 2).
The yield is only 38% which may be attributed to the steric
effect of the trityl cation. This same effect prevents protonation
of 3f to yield 2f. As expected, the 31P NMR spectra of 2f and
3f both display two doublet resonances. Treatment of 3b with
HgCl2 also produces a vinylidene product {[Ru]dCdC(Ph)-
CH(HgCl)CN}+ (2g), with 81% yield. The formation of these
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6436 J. Am. Chem. Soc., Vol. 118, No. 27, 1996
Ting et al.
Figure 2. An ORTEP drawing (33% thermal ellipsoid) of 3f with some
of the phenyl groups on the phosphine ligands and hydrogen atoms
eliminated for clarity. Selected bond distances (Å) and angles follow
(deg): Ru-C(6), 2.069(14); C(6)-C(7), 1.589(18); C(6)-C(9), 1.332-
(20); C(7)-C(9), 1.503(19); C(7)-C(8), 1.584(19); C(7)-C(10), 1.522-
(19); C(10)-N, 1.129(18); Ru-C(6)-C(9), 157.1(11); Ru-C(6)-C(7),
139.1(10); C(7)-C(6)-C(9), 61.2(9); C(6)-C(7)-C(9), 51.0(8); C(6)-
C(9)-C(7), 67.9(10); C(7)-C(10)-N, 175.7(14).
Figure 1. An ORTEP drawing (50% thermal ellipsoid) of 3b with
some of the phenyl groups on the phosphine ligands and hydrogen
atoms eliminated for clarity. Selected bond distances (Å) and angles
follow (deg): Ru-C(6), 2.034(5); C(6)-C(7), 1.289(8); C(6)-C(8),
1.579(10); C(7)-C(8), 1.452(10); C(8)-C(9), 1.215(16); C(9)-N(10),
1.102(18); Ru-C(6)-C(7), 169.7(4); Ru-C(6)-C(8), 130.4(4); C(7)-
C(6)-C(8), 59.8(4); C(6)-C(7)-C(8), 70.1(5); C(6)-C(8)-C(7), 50.1-
(4); C(8)-C(9)-N(10), 170.1(13).
spectrum is the presence of a triplet resonance at δ 154.6 (JC-P
) 19.0 Hz) assignable to CR. By monitoring the reaction using
vinylidene complexes occurs by selective cleavage of the
cyclopropenyl single bond near the metal center. This selectivity
is similar to what has been reported for the unsymmetrical
cyclopropenes where the methyl-substituted single bond is
cleaved.33 Attempts to carry out cyclopropenation of 2g by
using n-Bu4NOH, n-Bu4NF, and DBU result in cleavage of the
C-Hg bond yielding 3b.
31P NMR spectroscopy, [Ru]-CdC(Ph)CHCOOMe (3h) was
also observed at the initial stage of the reaction which gets
converted to 4h in acetone within 30 min at room temperature.
The reaction, if carried out at 5 °C, yields 3h as a major product
and 1a as a minor product, without formation of 4h. Complex
3h in MeOH is susceptible to protonation whereas no reaction
is observed between 4h and MeOH. However, protonation of
4h by acetic acid regenerates 2h quantitatively.
Owing to high strain energy of the cyclopropene ring, a more
stable five-membered furan ring is expected to be the thermo-
dynamic product. The fact that formation of 3h can be observed
may imply that the deprotonation step yields a zwitterionic
transition state with two resonance forms A (keto ester) and B
(enol ester) (Scheme 3), which subsequently produce 3h and
4h, respectively. Lack of 4h in the products at 5 °C can be
interpreted in terms of the absence of enol form B at this
temperature. The formation of 3h is favored by the proximity
of CR and Cγ of the vinylidene ligand in 2h as well as lower
mobility of the ester group at low temperature.
The thermal or photochemical ring opening of substituted
cyclopropenes affords vinylcarbene intermediates in a reversible
manner. Numerous examples of trapping of these species have
been reported.34 Cyclizations of alkynol and epoxyalkyne
catalyzed by Mo complex have also been recently reported.35
In these reactions, vinylidene and epoxyvinylidene have been
proposed as intermediates. The effect of substituents on the
selectivity of vinylcarbene formation depends upon whether
thermal or photochemical activation is used, which is exam-
Structures of Two Ru Cyclopropenyl Complexes. The
molecular structures of 3b and 3f have been determined by
X-ray diffraction studies. The two optical isomers of 3b have
been observed to crystallize together. An ORTEP drawing of
one isomer of 3b is shown in Figure 1. The Ru-C(6) bond
length of 2.034(5) Å is typical for a Ru-C single bond and the
C(6)-C(7) bond length of 1.289(8) Å is a double bond,
indicating the coordination of the sp2 carbon of the cyclopro-
penyl ligand. The bond angles Ru-C(6)-C(7) and C(6)-
C(7)-C(11) of 169.7(4)° and 156.2(5)°, respectively, are both
far greater than that of an idealized C(sp2) hybridization. The
C(6)-C(8) and C(7)-C(8) bond lengths of 1.58(1) and 1.45-
(1) Å, respectively, are significantly different, conforming with
the favorable cleavage of the C(6)-C(8) bond described above.
The phenyl group on the three-membered ring is approximately
coplanar with the cyclopropene and lies far away from the Cp.
An ORTEP drawing of 3f is shown in Figure 2. The C(6)-
C(7) and C(7)-C(9) bond lengths of 1.59(2) and 1.50(2) Å,
respectively, again differ significantly. The phenyl ring on Câ
is no longer parallel to the three-membered ring, probably due
to the steric hindrance between the CPh3 unit and the phenyl
group on the cyclopropenyl moiety. This also indicates that
formation of the three-membered ring does not require the
presence of the phenyl group on Câ.
(34) (a) Davis, J. H.; Goddard, W. A., III; Bergman, R. G. J. Am. Chem.
Soc. 1976, 98, 4015. (b) Streeper, R. D.; Gardner, P. D. Tetrahedron Lett.
1973, 767. (c) York, E. J.; Dittmar, W.; Stevenson, J. R.; Bergman, R. G.
J. Am. Chem. Soc. 1972, 94, 2882; 1973, 95, 5680.
(35) McDonald, F. E.; Schultz, C. C. J. Am. Chem. Soc. 1994, 116, 9363.
(36) (a) Pincock, J. A.; Moutsokapas, A. Can. J. Chem. 1977, 55, 979.
(b) Komendantov, M. I.; Domnin, I. N.; Bulueheva, E. V. Tetrahedron 1975,
31, 2495.
(37) (a) Trost, B. M.; Flygare, J. A. J. Org. Chem. 1994, 59, 1078. (b)
Katritzky, A. R.; Li, J.; Gordeev, M. F. J. Org. Chem. 1993, 58, 3038. (c)
Tani, K.; Sato, Y.; Okamoto, S.; Sato, F. Tetrahedron Lett. 1993, 34, 4975.
(d) Arcadi, A.; Cacchi, S.; Larock, R. C.; Marinelli, F. Tetrahedron Lett.
1993, 34, 2813. (e) Marshall, J. A.; DuBay, W. J. J. Am. Chem. Soc. 1992,
114, 1450. (f) Fukuda, Y.; Shiragami, H.; Utimoto, K.; Nozaki, H. J. Org.
Chem. 1991, 56, 5816. (g) Takai, K.; Tezuka, M.; Kataoka, Y.; Utimoto,
K. J. Org. Chem. 1990, 55, 5310.
Another type of Cyclization Induced by Base. Deproto-
nation of [Ru]dCdC(Ph)CH2COOMe+, 2h, by n-Bu4NOH at
room temperature induces a different type of cyclization yielding
the neutral furan complex [Ru]-CdC(Ph)CHdC(OMe)O (4h)
(Scheme 3). Similar to cyclopropenation, this reaction also
occurs only in acetone. 4h is additionally obtained if n-Bu4NF
or DBU is used. The most characteristic feature in the 31P NMR
spectrum of 4h is a singlet resonance at δ 51.3 indicating lack
of an asymmetric center. Also noticeable in the 13C NMR
(33) Padwa, A.; Blocklock, T. J.; Getman, D.; Hatanaka, N.; Loza, R. J.
Org. Chem. 1978, 43, 1481.

Cyclopropenation of Ruthenium Vinylidene Complexes
J. Am. Chem. Soc., Vol. 118, No. 27, 1996 6437
Scheme 3
plified by the reactions of ester resulting in the production of
furans.36 Several methods have recently been developed for
furan synthesis.37 Other middle and late transition metal
complexes react with terminal alkynols to give cyclic oxacar-
benes.38
the bond cleavage occurs at the C-O bond near the Ru center.
Interestingly, the phenyl ring is near the Cp unit in the solid
state.
Unstable Vinyl Complex via Fluoride Attack at the
r-Carbon. No deprotonation was observed in the reaction of
+
[Ru]dCdC(Ph)CH2OCH3 (2j) with n-Bu4NOH or DBU in
Structure of the Ru Furan Complex. The molecular
structure of 4h has been determined by X-ray diffraction
analysis. The crystal is found to contain two independent
molecules, but with no essential structural difference between
them. An ORTEP drawing of one molecule is shown in Figure
3. The Ru-C(1A) bond length of 2.076(7) Å indicates a Ru-C
single bond and the C(1A)-C(2A) and C(9A)-C(10A) bond
lengths of 1.370(9) and 1.33(1) Å, respectively, are typical CdC
double bonds. As for the similar bonds in the three-membered
ring of 3b and 3f, the C(1A)-O(1A) bond length of 1.442(8)
Å near the Ru center in the five-membered ring is significantly
longer than the C(10A)-O(1A) bond length of 1.347(8) Å. This
is consistent with the result of protonation reaction in which
acetone. With a donor oxygen atom in 2j it is not unexpected
that the above-mentioned methodology is not suitable for the
preparation of the methoxy-substituted cyclopropenyl complex
even though the iron cyclopropenyl complex with a methoxy
substituent has been reported previously.26 Upon adding n-Bu4-
NF to 2j, a different but more conventional reaction pattern is
observed. Namely the reaction produces a yellow metal vinyl
complex [Ru]-C(F)dC(Ph)CH2OCH3 (5). In this case about
80% conversion occurred in acetone at 10 °C. Complex 5 is
soluble in CHCl3 and THF. However, upon dissolution at room
temperature, complex 5 immediately converts back to 2j.
Therefore the spectroscopic data are obtained at -40 °C. In
the 13C NMR spectrum of 5, a doublet resonance (3JC-F ) 21.8
Hz) at δ 70.8 (inverted in the DEPT-135 experiment) is assigned
to the methylene carbon. The coupling constant JP-F ) 47 Hz
of the doublet resonance at δ 50.2 in the 31P NMR spectrum is
consistent with that of the triplet resonance in the 19F NMR
spectrum.
The importance of ionic fluorides as proton abstractors in
base-assisted reactions,39 and also as a source of fluorine atoms
in the synthesis of orgnofluorine derivatives,40 has been well
documented. It can thus be expected that there should be factors
other than the basicity and nucleophilicity associated with the
ionic fluoride that govern the reactions of 2b and/or 2j with
n-Bu4NF. These factors associated with n-Bu4NF are not yet
clear.
(38) (a) Quayle, P.; Rahman, S.; Ward, E. L. M.; Herbert, J. Tetrahedron
Lett. 1994, 35, 3801. (b) Hinkle, R. J.; Stang, P. J.; Arif, A. M.
Organometallics 1993, 12, 3510. (c) Stang, P. J.; Huang, Y. H. J.
Organomet. Chem. 1992, 431, 247. (d) Le Bozec, H.; Ouzzine, K.; Dixneuf,
P. H. Organometallics 1991, 10, 2768. (e) O’Connor, J. M.; Pu, L.;
Rheingold, A. L. J. Am. Chem. Soc. 1990, 112, 6232. (f) Ditz, K. H.; Sturm,
W.; Alt, H. G. Organometallics 1987, 6, 1424. (g) Parlier, A.; Rudler, H.
J. Chem. Soc., Chem. Commun. 1986, 514. (h) Curtis, P. J.; Davies, S. G.
J. Chem. Soc., Chem. Commun. 1984, 747.
(39) (a) Clark, J. H. Chem. ReV. 1980, 80, 429. (b) Jakobson, G. G.;
Akmentova, N. E. Synthesis 1983, 169. (c) Clark, J. H. J. Chem. Soc.,
Chem. Commun. 1978, 789. (d) Landini, D.; Maia, A.; Rampoldi, A. J.
Org. Chem. 1989, 54, 328.
Figure 3. An ORTEP drawing (50% thermal ellipsoid) of 4h with
some of the phenyl groups on the phosphine ligands and hydrogen
atoms eliminated for clarity. Selected bond distances (Å) and angles
follow (deg): Ru-C(1A), 2.076(7); C(1A)-C(2A), 1.370(9); C(1A)-
O(1A), 1.442(8); C(2A)-C(9A), 1.454(10); C(9A)-C(10A), 1.330-
(10); C(10A)-O(1A), 1.347(8); C(10A)-O(2A), 1.358(9); O(2A)-
C(11A), 1.395(11); Ru-C(1A)-C(2A), 140.0(5); Ru-C(1A)-O(1A),
115.7(4); O(1A)-C(1A)-C(2A), 104.3(5); C(1A)-C(2A)-C(9A),
109.5(6); C(2A)-C(9A)-C(10A), 105.7(6); C(9A)-C(10A)-O(1A),
111.5(6); C(10A)-O(1A)-C(1A), 109.0(5).
(40) (a) Chi, D. Y.; Kilbourn, M. R.; Katzenellenbogen, J. A. J. Org.
Chem. 1987, 52, 658. (b) Haas, A.; Lieb, M. Chimia 1985, 39, 134. (c)
Cox, D. P.; Terpinsky, J.; Lawrynowicz, W. J. Org. Chem. 1984, 49, 3216.

6438 J. Am. Chem. Soc., Vol. 118, No. 27, 1996
Ting et al.
Scheme 4
Figure 4. An ORTEP drawing (50% thermal ellipsoid) of 6b with
some of the phenyl groups on the phosphine ligands and hydrogen
atoms eliminated for clarity. Selected bond distances (Å) and angles
follows (deg): Ru-C(1), 1.811(10); C(1)-C(2), 1.328(14); C(2)-C(9),
1.542(15); C(9)-C(10), 1.602(14); C(10-C(11), 1.546(15); C(11)-
C(12), 1.379(15); C(12)-C(13), 1.358(16); C(13)-C(14), 1.416(16);
C(14)-C(15), 1.426(16); C(14)-C(16), 1.393(16); C(16)-C(17),
1.365(16); C(11)-C(17), 1.380(15); C(9)-C(18), 1.486(15); C(10)-
C(19), 1.490(15); C(10)-C(20), 1.442(15); C(15)-C(21), 1.397(16);
C(15)-C(22), 1.390(17); C(18)-N(1), 1.116(14); C(19)-N(2), 1.120-
(14); C(20)-N(3), 1.111(15); C(21)-N(4), 1.143(15); C(22)-N(5),
1.147(16); Ru-C(1)-C(2), 173.7(8); C(1)-C(2)-C(9), 117.8(9);
C(2)-C(9)-C(10), 114.6(8).
Scheme 5
in the solvent cage. Complex 6b, a light orange colored solid,
displays a characteristic dark violet-red color in solution, and
its spectroscopic data display the feature of a vinylidene
complex. The pattern of two-doublet resonances at δ 40.6, 38.8
with JP-P ) 26.6 Hz in the 31P NMR spectrum arises from the
asymmetric Cγ center. Localization of the negative charge at
the free terminus of TCNQ causes the Ru center to display the
cationic feature which is evidenced by chemical shift in these
31P NMR resonances in the same region as that of other cationic
complexes. The structure of 6b has also been determined by
X-ray diffraction analysis. An ORTEP drawing is shown in
Figure 4. The newly formed C(9)-C(10) bond is rather weak
as indicated by its extensively long bond length (1.60(1) Å).
Addition of TCNQ to 4h also opens up the five-membered ring
and produces the zwitterionic complex [Ru]dCdC(Ph)CH-
(COOMe)(TCNQ) (6h) with 88% yield. Complex 6h has been
characterized by spectroscopic methods. The 31P NMR spec-
trum of 6h exhibits two doublets at δ 40.0 and 38.7 which are
very close to that of 6b.
The reaction of TCNQ with 3d produces a different zwitte-
rionic vinylidene complex [Ru]dCdC(Ph)CHdCHCH2(TCNQ),
(7d) with TCNQ attached to the terminal carbon atom of the
allylic unit (Scheme 5). This reaction has to be carried out at
-40 °C because of the higher reactivity of 3d. The relatively
more electron-rich vinyl group, instead of the sp3 carbon of the
three-membered ring, of 3d serves as a better nucleophilic
center. This causes a shift of the double bond to Cγ-Cδ.
Spectroscopic data clearly reveal the site of electrophilic
addition. The doublet resonance at δ 2.64, assignable to the
CH2 group, in the 1H NMR spectrum of 7d and the correspond-
ing inverted resonance at δ 46.4 in the 13C NMR DEPT-135
Electrophilic Addition of TCNQ to Cyclopropenyl Com-
plexes. By comparing the protonation reactions of our neutral
cyclopropenyl complexes, which lead to formation of cationic
vinylidene complexes, with the same type of reaction of a similar
complex reported in the literature,26 it can be noted that the
complex consisting of a methoxy substituent, which leads to
cyclopropenylium complex upon protonation, behaves very
differently from those without such a group. It is thus clear
that the sp3 carbon center of the cyclopropenyl complexes 3
without an alkoxy group is an electron-rich center. Thus it
would be impossible to use the simple nucleophilic substitution
reaction for direct addition of groups such as -CN or -OMe
to the three-membered ring. However, by using TCNQ
[(NC)2C(C6H4)C(CN)2], it becomes viable to first add nucleo-
philes to the cyclopropenyl CR and then transfer to the Câ carbon
leading to formation of various MeO-substituted complexes. The
following section describes the chemical reactivity of various
complexes involving TCNQ.
clearly indicate an aliphatic CH2 unit in the molecule.
A
Addition of TCNQ to 3b yielded the zwitterionic complex
[Ru]dCdC(Ph)CH(CN)(TCNQ) (6b) (Scheme 5). One termi-
nus of TCNQ probably acts as an electrophile, adding to the
methyne carbon and resulting in the formation of a C-C bond.
An alternative pathway would be a single electron transfer (SET)
process41 followed by a subsequent fast C-C bond formation
terminal vinyl group would give an inverted 13C resonance for
the dCH2 unit at a much lower field region. The coupling
constant JH-H of 15.1 Hz between the olefinic protons indicates
a trans configuration at the double bond. In the 31P NMR
spectrum, only a singlet resonance at δ 41.2 was observed.
Cyclopropenyl Complexes with a Methoxy Substituent.
Attempted deprotonation of 6b using n-Bu4NOH did not result
in the formation of the expected cyclopropenyl complex
(41) (a) Tanko, J. M.; Drumright, R. E.; Suleman, N. K.; Brammer, L.
E. J. Am. Chem. Soc. 1994, 116, 1785. (b) Tolbert, L. M.; Sun, X. J.;
Ashby, E. C. J. Am. Chem. Soc. 1995, 117, 2681.

Cyclopropenation of Ruthenium Vinylidene Complexes
J. Am. Chem. Soc., Vol. 118, No. 27, 1996 6439
Scheme 6
containing TCNQ. However, in this reaction, the solvent
molecule of the added base, i.e. MeOH, serves as a reactant in
the presence of n-Bu4NOH giving the light yellow complex
[Ru]-CdC(Ph)C(OMe)CN (9b) with 88% yield. In the
absence of n-Bu4NOH, no reaction occurred. The base system
n-Bu4NOH/MeOH however can be replaced by the MeONa/
MeOH system. Replacing MeOH with EtOH yields the ethoxy-
substituted product [Ru]-CdC(Ph)C(OEt)CN (9b′). The re-
agents without alcohol such as n-Bu4NF/THF or DBU in THF
result in formation of a complicated mixture. The steps that
lead to the product are removal of proton by base accompanied
by the cyclization, followed by displacing TCNQ with the OMe
group. At the initial stage of this reaction in acetone, a mixture
Figure 5. An ORTEP drawing (50% thermal ellipsoid) of 9b with
some of the phenyl groups on the phosphine ligands and hydrogen
atoms eliminated for clarity. Selected bond distances (Å) and angles
follow (deg): Ru-C(1), 2.036(3); C(1)-C(2), 1.541(4); C(1)-C(3),
1.319(4); C(2)-C(3), 1.447(5); C(2)-O, 1.474(4); C(2)-C(10), 1.429-
(5); C(10)-N, 1.098(5); O-C(11); 1.178(6); Ru-C(1)-C(2), 132.1-
(2); Ru-C(1)-C(3), 167.7(3); C(2)-C(1)-C(3), 60.2(2); C(1)-C(2)-
C(3), 52.3(2); C(1)-C(3)-C(2), 67.5(2); C(2)-O-C(11), 130.9(5);
C(2)-C(10)-N, 156.0(5).
of two isomeric products 9b and [Ru]-C(OMe)C(Ph)dCCN
(8b), i.e. the methoxy group at CR, is observed when the reaction
is monitored by the 31P NMR spectra (Scheme 6). Pure 8b
can, however, be obtained by a different method which is
described below. Complex 8b is stable in CDCl3 or in THF,
but converts to 9b in acetone. In the 31P NMR spectrum of 9b
the characteristic two doublet resonances at δ 51.7, 49.6 with
JP-P ) 36.0 Hz are observed whereas CR appears as a triplet
resonance at δ 136.2 with JP-C ) 19.8 Hz in the 13C NMR
spectrum. For 9b′, in addition to the two-doublet 31P reso-
due to the chiral center at the ring. The ethyl analogue 8b′ is
kinetically more stable, i.e. at the initial stage of reaction only
8b′ was observed. In order to firmly establish the location of
the methoxy group, the crystal structure of 9b has been
determined. An ORTEP drawing of 9b is shown in Figure 5.
The phenyl group on Câ is again approximately coplanar with
the three-membered ring. Interestingly, a longer bond length
of C(1)-C(2) (1.541(4) Å) as compared to that of C(2)-C(3)
(1.447(5) Å) is also observed.
1
nances, the H NMR spectrum displays resonances with two
multiplet patterns which may be assigned to the OCH2 group
and arise due to the chiral center of the three-membered ring.
The fact that base reagents without alcohol produce a
complicated mixture probably indicates that the deprotonation
is followed by various decomposition pathways. Furthermore,
the fact that the reaction requires the presence of base leads us
to believe that the deprotonation step may still be the first step
in the formation of 9b. Cleavage of the weak Cγ-C(TCNQ)
bond accompanying the attachment of the MeO group initially
to CR followed by a shift to Câ satisfactorily accounts for the
formation of 9b. In the 31P NMR spectrum of 8b the two-
doublet (at δ 51.2 and 50.7 with JP-P ) 29.6 Hz) pattern arises
Protonation of 8b or 9b removes the methoxy group and
produces the cyclopropenylium complex, [Ru]-CC(Ph)CCN+
(10b), with 78% yield (Scheme 6). The symmetrical planar
structure of the three-membered ring of 10b is revealed by the
31P NMR spectrum, which shows only a singlet resonance at δ

6440 J. Am. Chem. Soc., Vol. 118, No. 27, 1996
Ting et al.
Scheme 7
46.8. In the 13C NMR spectrum the resonance attributed to the
CR appears at δ 213.0 with JC-P ) 17.2 Hz. This reactivity is
very different from opening of the three-membered ring of 3,
yet similar to the reactivity of organic cyclopropene with a
methoxy substituent.42 Reaction of MeONa with 10b in THF
yields pure 8b which converts to 9b in acetone in about 40
min.
complex [Ru]dCdC(Ph)CH(CN)2+ (2m) instead of the cyclo-
propenylium complex (Scheme 6). This result further reveals
the unique influence of the methoxy group present in the three-
membered ring which effectively controls the protonation
reaction of the cyclopropenyl complexes.
Oxidative Coupling Reactions of Metal Cyclopropenyl
Complexes. On the basis of successful addition of the trityl
group to 3b, we attempted to induce a C-C bond formation in
3b by using organic halides and found the formation of a new
coupling product in the presence of allyl iodide. Treatment of
3b with a 20-fold excess of allyl iodide affords the dimeric
dicationic vinylidene complex {[Ru]dCdC(Ph)CHCN}22+ (11)
with 49% yield (Scheme 7). The yield of 11 depends on the
amount of allyl iodide used. If only 1 equiv of allyl iodide is
used, this reaction slowly produces 2b as a major product and
only a trace amount of 11. Using other organic iodides such
as methyl iodide, ethyl iodide, and iodobenzene produces no
coupling product. The reactions of 3c or 3d with allyl iodide
also do not produce the coupling product.
Similarly a suspension of complex 6h in acetone undergoes
methanolysis to yield [Ru]-CdC(Ph)C(CO2Me)(OMe) (9h),
another MeO-substituted cyclopropenyl complex with 60% yield
(Scheme 6). The high solubility of 9h in acetone, however,
hinders direct precipitation. The complex is hence purified by
hexane extraction. The 31P NMR (two doublets at δ 53.6 and
1
48.0) and the H NMR (two methyl resonances at δ 3.63 and
3.29) spectra of 9h are consistent with its formulation. Unlike
3h which converts to 4h, complex 9h stabilized by the methoxy
group does not convert to a substituted furan. The three-
membered ring of 9h remains unchanged even at 45 °C in
acetone. The effect of the MeO group in stabilizing the
cyclopropenyl ring is consistent with what has been observed
in many analogous organic compounds.42 With the TCNQ
group present at a distant carbon atom, complex 7d is inert in
n-Bu4NOH/MeOH. Protonation of 9h again removes the
methoxy group giving the cationic cyclopropenylium complex
Complex 11 is insoluble in most of the organic solvents and
only sparingly soluble in DMSO wherein it forms an orange
solution. The mass spectrum of 11 is consistent with the
formulation {[Ru]dCdC(Ph)CHCN}2I+. In the 31P NMR
spectrum of 11, the chemical shift of the resonances at δ 41.3
and 42.3 is close to that observed for 2. The molecular structure
of 11 has also been determined by X-ray diffraction analysis.
[Ru]-CC(Ph)C(CO2Me)+ (10h). The 31P NMR spectrum of
10h displays only a singlet at δ 47.6, characteristic of a cationic
cyclopropenylium complex, where only one methyl resonance
-
Interestingly, the counterions in the solid state are two I3
anions. A view of one molecule of 11 is shown in Figure 6.
The center of the central C-C bond lies on a center of
symmetry, thus half of the molecule is symmetry-generated from
the other. The Ru-C(6) bond length of 1.83(2)Å is consistent
with the RudC double bond formulation and the Ru-C(6)-
C(7) bond angle of 174(2)° is similar to that in related vinylidene
complexes.
The formation of 11 probably involves the cationic ruthenium
vinylidene radical43 induced from the reaction of 3b with C3H5I.
The coupling of the allyl radical resulting in the formation of
the bicyclopropyl molecule44 and radical annulations of allyl
iodomalononitriles45 have been reported in the literature.
Oxidative carbon-carbon coupling of the cationic iron vi-
nylidene complex [Cp(dppe)FedCdCHMe]+ leading to forma-
tion of [Cp(dppe)FedCdCMe]22+ has been reported,46 whereas
1
at δ 3.80 is observed in the H NMR spectrum.
However, the presence of a stronger nucleophile prohibits
formation of the MeO-substituted complex 9. For example, the
reaction of n-Bu4NCN in the presence of MeOH with 6b does
not yield 9b but brings about addition of the CN group with
removal of TCNQ, giving [Ru]-CdC(Ph)C(CN)2, (3m). Ac-
companied by deprotonation, the stronger nucleophile CN-
displaces TCNQ to form the product. Further protonation of
3m, lacking the MeO substituent, produces the vinylidene
(42) (a) Breslow, R.; Chang, H. W. J. Am. Chem. Soc. 1961, 83, 2367.
(b) Krebs, A. W. Angew. Chem., Int. Ed. Engl. 1965, 4, 10. (c) Closs, G.
L.; Boll, W. A.; Heyn, H.; Dev, V. J. Am. Chem. Soc. 1968, 90, 173.
(43) (a) Rabier, A.; Lugan, N.; Mathieu, R.; Geoffroy, G. L. Organo-
metallics 1994, 13, 4676. (b) Antinolo, A.; Otero, A.; Fajardo, M.; Garcia-
Yebra, C.; Gil-Sanz, R.; Lopez-Mardomingo, C.; Martin, A.; Gomez-Sal,
P. Organometallics 1994, 13, 4679.
(44) Holtzhauer, K.; Cometta-Morini, C.; Oth, J. F. M. J. Phys. Org.
Chem. 1990, 3, 219.
(45) Curran, D. P.; Seong, C. M. Tetrahedron 1992, 48, 2175.
(46) Lyer, R. S.; Selegue, J. P. J. Am. Chem. Soc. 1987, 109, 910.
(47) Le Narvor, N.; Toupet, L.; Lapinte, C. J. Am. Chem. Soc. 1995,
117, 7129.
(48) Connelly, N. G.; Gamasa, M. P.; Gimeno, J.; Lapinte, C.; Lastra,
E.; Maher, J. P.; Le Narvor, N.; Rieger, A. L.; Rieger, P. H. J. Chem. Soc.,
Dalton Trans. 1993, 2575.
Figure 6. An ORTEP drawing (33% thermal ellipsoid) of 11 with
some of the phenyl groups on the phosphine ligands and hydrogen
atoms eliminated for clarity. Selected bond distances (Å) and angles
follow (deg): Ru-C(6), 1.826(20); C(6)-C(7), 1.34(3); C(7)-C(8),
1.52(3); C(8)-C(8a), 1.49(3); C(8)-C(9), 1.56(3); C(9)-N(10), 1.12-
(3); Ru-C(6)-C(7), 174.4(16); C(6)-C(7)-C(8), 120.6(17); C(7)-
C(8)-C(8a), 114.7(16); C(8)-C(9)-N(10), 178.1(20).

Cyclopropenation of Ruthenium Vinylidene Complexes
J. Am. Chem. Soc., Vol. 118, No. 27, 1996 6441
another very similar coupling47 has been attributed to the
presence of 17-electron species, confirmed by ESR.48 Unsub-
stituted vinylidene complex Cp(PPh3)2RudCdCH2 also under-
goes oxidative coupling by MeI and produces a similar dimer.49
There are also few examples of metal acetylide couplings.50 The
possible role of azavinylidene51 in the conversion of nitriles to
diimido-bridged dimer in tantalum and niobium complexes52
has been recently addressed. These examples are, nevertheless,
different from what is observed in 3b, namely in our system
the oxidative coupling at Cγ results in formation of a C6 bridge
between the Ru metal centers. Complex 11 undergoes two
deprotonation/cyclopropenation in the presence of excess n-Bu4-
NOH to give the neutral 2,2′-bicyclopropenyl complex {[Ru]-
of δ with residual protons in the solvent as an internal standard (CDCl3,
δ 7.24; CD3CN, δ 1.93; C2D6CO, δ 2.04). FAB mass spectra were
recorded on a JEOL SX-102A spectrometer. Complexes 1a, [Ru]-
CtC-C6H9,55 1k, and [Ru]dCdC(Ph)CH2R+ (2c, R ) Ph; 2d, R )
CHdCH2)56 were prepared following the methods reported in the
literature. Elemental analyses and X-ray diffraction studies were carried
out at the Regional Center of Analytical Instrument located at the
National Taiwan University.
Synthesis of [[Ru]dCdC(Ph)CH2CN][PF6] (2b). A Schlenk flask
was charged with complex 1a (0.475 g, 0.60 mmol) and NH4PF6 (0.123
g, 0.75 mmol) and CH2Cl2 (20 mL) were added after the atmosphere
was replaced with nitrogen. The resulting solution was stirred at room
temperature and ICH2CN (0.1 mL, 1.5 mmol) was added. The clear
solution was stirred for 18 h, then the solvent was reduced to about 5
mL. This mixture was slowly added to 60 mL of Vigorously stirred
diethyl ether. The pale red precipitate thus formed was filtered off
and washed with diethyl ether and hexane. The product was recrystal-
lized from CH2Cl2/hexane (1:5) and identified as 2b (0.42 g, 0.43 mmol,
72%). Spectroscopic data of 2b: 1H NMR CD3COCD3: 8.16-7.03
(Ph); 5.61 (s, 5H, Cp); 3.56 (s, 2H, CH2). 13C NMR CD3COCD3: 345.6
(t, JP-C ) 17.9 Hz, CR); 134.8-128.4 (Ph); 123.0 (Câ); 118.5 (CN);
95.6 (Cp); 14.5 (CH2). 31P NMR CD3COCD3: 42.4 (s). MS FAB
m/z: 834 (M+, Ru ) 104), 572 (M+ - PPh3), 431 (M+ - PPh3, C2-
PhCH2CN). Anal. Calcd for C51H42NP3F6Ru: C, 62.70; H, 4.33; N,
1.43. Found: C, 62.90; H, 4.15; N, 1.96.
CdC(Ph)CCN}2 (12). Complex 12 displays the typical light
yellow orange color of the cyclopropenyl complexes. Product
analyses included elementary analysis, mass spectroscopy, and
1H NMR spectroscopy which shows characteristic Cp absorption
at δ 4.87. Similar to 11, complex 12 also displays the
characteristic AB pattern in its 31P NMR spectrum. The
unsubstituted 2,2′-bicyclopropene has been prepared53 and its
structure has been determined by X-ray diffraction analysis at
103 K.54
Conclusion. The facile preparation of neutral Ru cyclopro-
penyl complexes has been achieved by deprotonation of a CH
or CH2 unit at Cγ of the cationic vinylidene complexes in
acetone. Successful accomplishment of the preparation of
complexes with various substituents such as CN, Ph, and vinyl
groups at CH or CH2 renders this preparation a potentially
versatile synthetic method. The deprotonation of vinylidene
complexes consisting of an ester group yields the five-membered
furan moiety as thermodynamic products. Protonation of both
of the cyclization products, yielding back the vinylidene
complexes, shows the nucleophilic nature of the antecedent Cγ
carbon of the vinylidene ligand. Thus other electrophiles could
also be added to this same Cγ site by reaction with cyclopro-
penyl or furan complex. However, when TCNQ was employed
for this purpose, the addition could be modified leading
eventually to the formation of cyclopropenyl complex with a
methoxy substituent, which displays higher stability of the three-
membered ring and shows particular reactivity. Thus in the
present system, use of TCNQ appears to serve as an entry to
the cyclopropenylium complex. A cyclopropenyl complex with
a methoxy group behaves differently from that without such a
unit.
Complex [[Ru]dCdC(Ph)CH2CHdCMe2][PF6] (2e) (0.84 g, 0.81
mmol, 77% yield from 0.85 g of 1a) was similarly prepared from
BrCH2CHdCMe2. Spectroscopic data of 2e: 1H NMR CDCl3: 7.38-
6.85 (m, 35H, Ph); 5.04 (s, 5H, Cp); 4.92 (m, 1H, dCH); 2.90 (d,
JH-H ) 6.5 Hz, 2H, CH2); 1.58, 1.11 (s, 6H, 2 CH3). 13C NMR
CDCl3: 348.9 (t, JP-C ) 15.8 Hz, CR); 134.7-124.7 (Ph); 119.8 (Câ);
94.1 (Cp); 25.8, 25.6 (2 CH3); 17.6 (CH2). 31P NMR CDCl3: 42.7 (s).
MS FAB m/z: 863 (M+), 601 (M+ - PPh3), 431 (M+ - PPh3, C2-
PhCH2CHCMe2). Anal. Calcd for C54H49P3F6Ru: C, 64.47; H, 4.91.
Found: C, 64.80; H, 4.65.
Complex [[Ru]dCdC(Ph)CH2COOMe][PF6] (2h) was prepared
using the following method. A mixture of complex 1a (1.15 g, 1.45
mmol) and BrCH2COOMe (0.5 mL, 5.1 mmol) in 40 mL of CH2Cl2/
CHCl3 (3:1) was heated to refulx for 8 h, then NH4PF6 (0.25 g, 1.53
mmol) was added and the mixture was stirred at room temperature for
4 h. The workup procedure was the same as that for 2b. Purification
by recrystallization from CH2Cl2/hexane (1:5) gave 2h (0.91 g, 0.90
mmol, 62% yield). Spectroscopic data of 2h: 1H NMR CD3COCD3:
7.50-7.06 (m, 35H, Ph); 5.52 (s, 5H, Cp); 3.65 (s, 3H, CH3); 3.10 (s,
2H, CH2). 13C NMR CDCl3: 347.8 (JP-C ) 14.6 Hz, CR); 171.7 (s,
CO2); 134.4-128.3 (Ph); 125.1 (Câ); 90.7 (Cp); 52.2 (CH3); 32.1 (CH2).
31P NMR CDCl3: 42.0 (s). MS FAB m/z: 867 (M+), 721 (M+ - C2-
PhCH2COOMe + CO), 693 (M+ - C2PhCH2COOMe), 431 (M+
-
PPh3, C2PhCH2COOMe). Anal. Calcd for C52H45O2P3F6Ru: C, 61.84;
H, 4.49. Found: C, 62.23; H, 4.71.
Complex [[Ru]dCdC(Ph)CH2COOEt][PF6] (2i) was prepared in
68% isolated yield using the same procedure as that for 2h. Spectro-
scopic data of 2i: 1H NMR CDCl3: 7.40-6.88 (m, 35H, Ph); 5.22 (s,
5H, Cp); 4.08 (q, JH-H ) 7.13 Hz, 2H, OCH2); 3.00 (s, 2H, CH2); 1.15
(t, JH-H ) 7.13 Hz, 3H, CH3). 13C NMR CDCl3: 347.8 (JP-C ) 15.1
Hz, CR); 171.2 (s, CO2); 134.3-128.3 (Ph); 125.1 (Câ); 94.8 (Cp); 61.2
(CH2CO2); 32.3 (OCH2); 14.1 (CH3). 31P NMR CDCl3: 42.1 (s). MS
FAB m/z: 882 (M+), 619 (M+ - PPh3), 431 (M+ - PPh3, C2PhCH2-
COOEt). Anal. Calcd for C53H47O2P3F6Ru: C, 62.17; H, 4.63.
Found: C, 62.62; H, 4.50.
Experimental Section
General Procedures. All manipulations were performed under
nitrogen using vacuum-line, dry box, and standard Schlenk techniques.
CH3CN and CH2Cl2 were distilled from CaH2 and diethyl ether and
THF from Na/ketyl. All other solvents and reagents were of reagent
grade and were used without further purification. NMR spectra were
recorded on Bruker AC-200 and AM-300WB FT-NMR spectrometers
at room temperature (unless states otherwise) and are reported in units
(49) Bruce, M. I.; Koutsantonis, G. A. Aust. J. Chem. 1991, 44, 207.
(50) (a) Shih, K.-Y.; Schrock, R. R.; Kempe, R. J. Am. Chem. Soc. 1994,
116, 8804. (b) Evans, W. T.; Keyer, R. A.; Ziller, J. W. Organometallics
1993, 12, 2618. (c) Shutowski, D. G.; Stucky, G. D. J. Am. Chem. Soc.
1976, 98, 1376.
(51) Feng, S. G.; White, P. S.; Templeton, J. L. J. Am. Chem. Soc. 1994,
116, 8613.
(52) (a) Finn, P. A.; King, M. S.; Kilty, P. A.; McCarley, R. E. J. Am.
Chem. Soc. 1975, 97, 220. (b) Cotton, F. A.; Hall, T. W. Inorg. Chem.
1978, 17, 3525. (c) Roskamp, E. J.; Pedersen, S. F. J. Am. Chem. Soc.
1987, 109, 3152.
(53) Billups, W. E.; Haley, M. M. Angew. Chem., Int. Ed. Engl. 1989,
28, 1711.
Synthesis of [[Ru]dCdC(Ph)CH2OCH3][PF6] (2j). The synthetic
procedure was similar to that used for the preparation of 2b: A solution
of 1a (0.923 g, 1.16 mmol) in 20 mL of CH2Cl2, ICH2OCH3 (0.15
mL, 1.17 mmol) (Caution: Free ICH2OCH3 is a potential carcinogen),
and NH4PF6 (0.27 g, 1.66 mmol) were used. The reaction was
completed immediately upon mixing of the reactants. The product was
recrystallized from CH2Cl2/hexane (1:5) and identified as 2j (0.87g,
0.88 mmol, 76%). Spectroscopic data of 2j: 1H NMR CD3CN: 7.93-
6.94 (Ph); 5.32 (s, 5H, Cp); 3.95 (s, 2H, CH2); 3.09 (s, 3H, CH3). 13
C
(55) Bruce, M. I.; Hinterding, P.; Tiekink, E. R. T.; Skeleton, B. W.;
White, A. H. J. Organomet. Chem. 1993, 450, 209.
(56) Bruce, M. I.; Humphrey, M. G. Aust. J. Chem. 1989, 42, 1067.
(54) Bordalla, D.; Mootz, D.; Boese, R.; Osswald, W. J. Appl. Crystal-
logr. 1985, 18, 316.

6442 J. Am. Chem. Soc., Vol. 118, No. 27, 1996
Ting et al.
NMR CD3CN: 348.5 (t, JC-P ) 16.1 Hz, CR); 135.9-128.8 (Ph); 118.2
(Câ); 95.7 (Cp); 67.5 (CH3); 57.8 (CH2). 31P NMR CD3CN: 42.5 (s).
MS FAB m/z: 839 (M+), 577 (M+ - PPh3), 431 (M+ - PPh3, C2-
PhCH2OMe). Anal. Calcd for C51H45OP3F6Ru: C, 62.38; H, 4.62.
Found: C, 62.11; H, 4.98.
thus a slightly modified procedure is used. To a solution of 2k (0.45
g, 0.47 mmol) in 15 mL of acetone was added a solution of n-Bu4-
NOH (2.0 mL). The solution was stirred for 3 h. Then the workup
procedure was the same as that for 3b. This product was identified as
3k (0.30 g, 0.36 mmol, 77% yield) which gave 2k quantitatively in
the presence of MeOH. Replacing n-Bu4NOH by n-Bu4NF or DBU
gave the same product with slightly lower yield. Spectroscopic data
for 3k: 1H NMR CDCl3: 7.44-6.97 (m, 30H, Ph), 5.41 (t, br, 1H,
dCH), 4.53 (s, 5H, Cp); 2.01, 1.63, 1.43, 1.35 (br, 4 CH2); 1.08 (s,
1H, CHCN). 13C NMR CDCl3: 140.0-127.0 (Ph), 126.2 (dCH in
C6H9), 116.2 (CN), 86.0 (Cp), 26.9, 25.6, 22.8, 22.3 (CH2 in C6H9),
7.7 (CHCN). 31P NMR CDCl3: 51.7, 49.0 (AB, JP-P ) 36.4 Hz, 2
PPh3). MS FAB m/z: 838 (M+ + 1), 693 (M+ - cyclopropenyl
moiety), 576 (M+ + 1 - PPh3), 431 (M+ - cyclopropenyl moiety,
PPh3). Anal. Calcd for C54H48P2Ru: C, 75.42; H, 5.63. Found: C,
75.23; H, 5.87.
Complex [[Ru]dCdC(C6H9)CH2CN]I (2k) (0.80 g, 0.82 mmol, 75%
yield) was prepared from 1k (0.87 g, 1.09 mmol) and ICH2CN using
the same procedure as for 2b. Spectroscopic data of 2k: 1H NMR
CDCl3: 7.44-6.96 (m, 30H, Ph); 5.77 (br, 1H, dCH); 5.18 (s, 5H,
Cp); 2.85 (s, 2H, CH2CN); 2.15, 1.84, 1.62, 1.53 (br, 8H, 4 CH2). 13
C
NMR CDCl3: 349.0 (t, br, CR); 134.4-128.8 (Ph); 125.0 (CH of C6H9);
124.2 (Câ); 118.5 (CN); 95.0 (Cp); 30.9, 28.0, 22.8, 21.6 (4 CH2); 12.7
(CH2CN). 31P NMR CDCl3: 41.1 (s). MS FAB m/z: 836 (M+), 574
(M+ - PPh3), 431 (M+ - C2(C6H9)CH2CN).
Synthesis of [Ru]CdC(Ph)C(CN)H (3b). To a solution of 2b (0.40
g, 0.41 mmol) in 15 mL of acetone was added a solution of n-Bu4-
NOH (4.5 mL, 1 M in MeOH). The mixture was stirred overnight
yielding the light yellow microcrystalline precipitate which was filtered
off and washed with 2 × 5 mL of acetone, 2 × 10 mL of diethyl ether,
and 10 mL of n-hexane, then dried under vacuum. The product was
analytically pure and was identified as 3b (0.27 g, 0.33 mmol, 80%).
When 2b was treated with n-Bu4NF (1 M in THF) or DBU, instead of
n-Bu4NOH, the same product was obtained. Single crystals suitable
for X-ray diffraction analysis were grown from the same reaction
mixture with lower concentration. Spectroscopic data of 3b: 1H NMR
CDCl3: 7.20-6.61 (m, 35H, Ph); 4.54 (s, 5H, Cp); 1.40 (s, 1H, CH).
13C NMR CDCl3: 134.8-128.4 (Ph); 126.2 (t, JC-P ) 23.0 Hz, CR);
113.8 (CN); 86.3 (Cp); 7.96 (CH). 31P NMR CDCl3: 51.7, 49.6 (AB,
JP-P ) 34.6 Hz). MS FAB m/z: 834 (M+ + 1), 572 (M+ - PPh3),
430 (M+ - PPh3, C2PhCHCN). Anal. Calcd for C51H41NP2Ru: C,
73.72; H, 4.97; N, 1.69. Found: C, 73.63; H, 4.55; N, 1.42.
Synthesis of [[Ru]dCdC(Ph)CH(CN)CPh3][PF6] (2f). To a solid
mixture of 3b (0.76 g, 0.91 mmol) and Ph3CPF6 (0.36 g, 0.93 mmol)
at 0 °C was added by syringe 25 mL of CH2Cl2. The mixture was
stirred for 40 min, and then the solvent was removed under vacuum.
The residue which contained 2f and 2b was washed with 3 × 20 mL
of benzene to remove 2b then with 2 × 10 mL of diethyl ether and
dried to give 2f (0.71 g, 0.58 mmol, 64%). The solvent of a portion
of 2b was removed and the residue was redissolved in CH2Cl2 and
poured into a stirred diethyl ether to give 2b (0.20 g, 0.21 mmol, 28%
yield). Spectroscopic data of 2f: 1H NMR CD3CN: 7.49-6.58 (Ph);
5.29 (s, 5H, Cp); 5.03 (s, 1H, CH). 13C NMR CD3CN: 340.3 (t, JC-P
) 16.5 Hz, CR); 135.9-128.8 (Ph); 125.3 (Câ); 122.6 (CN); 96.2 (Cp);
60.1 (CPh3); 36.0 (CH). 31P NMR CD3CN: 41.3, 38.6 (d, JP-P ) 26.5
Hz). MS FAB m/z: 1076 (M+), 834 (M+ - CPh3), 571 (M+
-
CPh3,PPh3). Anal. Calcd for C70H56NP3F6Ru: C, 68.96; H, 4.63; N,
1.15. Found: C, 68.70; H, 5.03; N, 1.09.
Synthesis of [[Ru]dCdC(Ph)CH(CN)HgCl]Cl (2g). To a mixture
of 3b (0.47 g, 0.56 mmol) and HgCl2 (0.19 g, 0.70 mmol) at 0 °C was
added by syringe 25 mL of CH2Cl2. The mixture was stirred for 40
min. The workup procedure was the same as that in 2f and no 2b was
observed. The product identified as 2g was obtained (0.55 g, 0.45
mmol, 81%). Spectroscopic data for 2g: 1H NMR CDCl3: 7.45-
6.76 (m, 35H, Ph), 5.32 (s, 5H, Cp), 3.62 (s, 1H, CH). 13C NMR
CDCl3: 344.3 (t, JC-P ) 13.1 Hz, CR), 134.5-127.1 (Ph), 125.2 (Câ),
120.9 (CN), 95.2 (Cp), 26.2 (CH). 31P NMR CD3CN: 42.4, 40.3 (AB,
JP-P ) 26.4 Hz, 2 PPh3). MS FAB m/z: 1070 (M+), 833 (M+ - HgCl),
693 (M+ - HgCl, C2PhCHCN), 571 (M+ - HgCl, PPh3).
Reaction of 2h with Bu4NOH. To a suspension of complex 2h
(0.94 g, 0.93 mmol) in 15 mL of acetone at room temperature was
added a 2.5-mL solution of n-Bu4OH. The solution gave orange
precipitate after being stirred overnight. The precipitate was filtered
and washed with 10 mL of MeOH, 2 × 5 mL of acetone, and 10 mL
of hexane and then dried under vacuum. Recrystallization from a
Synthesis of [Ru]-CdC(Ph)C(Ph)H (3c). Complex 3c (0.14 g,
0.16 mmol, 55% yield) was similarly prepared from 2c (0.30 g, 0.29
mmol) and n-Bu4NOH (3.0 mL) in 15 mL of acetone. Spectroscopic
data for 3c: 1H NMR CDCl3: 8.19-6.61 (m, 40H, Ph), 4.22 (s, 5H,
Cp), 2.54 (s, 1H, CH). 13C NMR CDCl3: 140.8-119.3 (Ph), 137.7 (t,
JC-P ) 19.7 Hz, CR), 85.2 (Cp), 32.9 (CH). 31P NMR CDCl3: 54.7,
47.8 (d, JP-P ) 34.9 Hz, 2 PPh3). MS FAB m/z: 885 (M+), 721 (M+
+ CO - C15H11), 693 (M+ - C15H11). Anal. Calcd for C56H46P2Ru:
C, 76.26; H, 5.26. Found: C, 76.56; H, 4.98.
Synthesis of [Ru]-CdC(Ph)C(C2H3)H (3d). Complex 3d was
similarly prepared from 2d (0.44 g, 0.45 mmol) and 5.0 mL of n-Bu4-
NOH in 10 mL of acetone. The product was obtained in 53% yield
(0.20 g, 0.24 mmol). Spectroscopic data for 3d: 1H NMR CDCl3:
7.45-6.63 (m, 35H, Ph), 5.84 (ddd, JH-H ) 17.0, 10.1, 9.2 Hz, 1H,
dCH), 5.24 (dd, JH-H ) 17.0, 2.5 Hz, 1H of dCH2), 4.78, (dd, JH-H
) 10.1, 2.5 Hz, 1H of dCH2), 4.49 (s, 5H, Cp), 2.02 (d, 1H, JH-H
)
9.2 Hz, CH). 13C NMR CDCl3: 153.8 (dCH), 138.4 (t, JC-P ) 19.3
Hz, CR), 135.5-123.7 (Ph), 105.9 (dCH2), 85.7 (Cp), 32.8 (CH). 31P
NMR CDCl3: 53.2, 49.9 (AB, JP-P ) 35.5 Hz, 2 PPh3). MS FAB
m/z: 835 (M+ + 1), 795 (M+ + 1 - C3H4), 721 (M+ + CO - C11H9),
693 (M+ - C11H9), 431 (M+ - C11H9,PPh3). Anal. Calcd for C52H44P2-
Ru: C, 75.07; H, 5.33. Found: C, 75.01; H, 5.22.
mixture of C6H12/CHCl3 (1:1) yielded [Ru]-CdC(Ph)CHdC(O)OCH3
(4h) (0.64 g, 0.74 mmol, 80% yield). Spectroscopic data for 4h: 1H
NMR CDCl3: 7.32-6.97 (m, 35H, Ph); 4.92 (s, 1H, CH); 4.05 (s, 5H,
Cp); 3.04 (s, 3H, CH3). 13C NMR CDCl3: 164.0 (CO2); 154.6 (t, JC-P
) 19.0 Hz, CR); 140.5-125.3 (Ph); 86.6 (Cγ); 83.9 (Cp); 58.0 (CH3).
31P NMR CDCl3: 51.3 (s). MS FAB m/z: 867 (M+ + 1), 721 (M+
C2PhCH(CO2Me) + CO), 693 (M+ - C2PhCH(CO2Me)), 431 (M+
-
-
Synthesis of [Ru]-CdC(Ph)C(CHdCMe2)H (3e). Complex 3e
in 48% yield (0.17 g, 0.20 mmol) was similarly prepared from 2e (0.43
g, 0.41 mmol) in 10 mL of acetone and n-Bu4NOH (4.5 mL).
Spectroscopic data for 3e: 1H NMR CDCl3: 7.61-6.62 (m, 35H, Ph),
4.94 (d, JH-H ) 9.4 Hz, 1H, CH), 4.39 (s, 5H, Cp), 1.94 (d, 1H, JH-H
) 9.4 Hz, dCH); 1.89, 1.70 (s, 2 CH3). 31P NMR CDCl3: 53.0, 50.2
(d, JP-P ) 35.7 Hz, 2 PPh3). MS FAB m/z: 863 (M+ + 1), 601 (M+
+ 1 - PPh3), 431 (M+ - C13H13,PPh3). Anal. Calcd for C54H48P2Ru:
C, 75.42; H, 5.63. Found: C, 75.23; H, 5.87. Protonation of 3b by
CF3COOH in CDCl3 was carried out in a NMR tube and the reaction
cleanly yielded 2b. The yield is >95% based on the integration of the
Cp resonances relative to an internal standard. Similarly protonation
of 3c, 3d, and 3e gave 2c, 2d, and 2e, respectively, all with >95%
NMR yields.
C2PhCH(CO2Me),PPh3). Anal. Calcd for C52H44O2P2Ru: C, 72.29;
H, 5.13. Found: C, 74.49; H, 5.75 (the deviation might be due to the
solvent trapped in the solid during recrystallization).
When the same reaction was carried out at 5 °C, [Ru]-CdC-
(Ph)CHdCOOCH3 (3h) and 1a with a ratio of 2:1 were isolated in
75% total yield. At this temperature, 4h was not observed. No attempt
was made to separate 3h and 1a. Spectroscopic data of 3h: 1H NMR
CDCl3: 7.50-6.54 (m, 35H, Ph); 4.40 (s, 5H, Cp); 3.72 (s, 3H, CH3);
2.12 (s, 1H, CH). 31P NMR CDCl3: 52.7, 48.0 (AB, JP-P ) 35.5 Hz).
Complex 3h was completely converted to 4h in CDCl3 at room
temperature for 4 h.
Complex [Ru]-CdC(Ph)CHdC(O)OEt (4i) (0.301 g, 0.340 mmol)
was similarly prepared from 2i (0.450 g, 0.440 mmol, 78% yield) and
n-Bu4NOH. Spectroscopic data for 4i: 1H NMR CDCl3: 7.34-6.91
Synthesis of [Ru]CdC(C6H9)C(CN)H (3k). The cyclopropenyl
complex with a cyclohexenyl group on the Câ was soluble in acetone

Cyclopropenation of Ruthenium Vinylidene Complexes
J. Am. Chem. Soc., Vol. 118, No. 27, 1996 6443
(m, 35H, Ph); 4.96 (s, 1H, CH); 4.05 (s, 5H, Cp); 3.09 (q, JH-H ) 7.01
Hz, 2H, OCH2); 0.91 (t, JH-H ) 7.01 Hz, 3H, CH3). 13C NMR
CDCl3: 162.7 (s, CO2); 154.7 (JP-C ) 17.5 Hz, CR); 142.3-125.2 (Ph);
88.6 (CHCO2); 83.8 (Cp); 66.7 (OCH2); 14.8 (CH3). 31P NMR
CDCl3: 51.2 (s). MS FAB m/z: 880 (M+), 721 (M+ + CO - C2-
PhCHCOOEt), 693 (M+ - C2PhCHCOOEt), 431 (M+ - PPh3, C2-
PhCHCOOEt). Anal. Calcd for C53H46O2P2Ru: C, 72.50; H, 5.28.
Found: C, 72.34; H, 5.10.
CH2). 13C NMR CD3COCD3: 355.8 (CR); 144.6-128.7 (Ph); 124.3,
118.0 (2 dCH); 119.2, 118.5 (4 CN); 95.1 (Cp); 46.4 (CH2); 42.2,
30.7 (2 C(CN)2). 31P NMR CDCl3: 41.2. MS FAB m/z: 1039 (M+),
835 (M+ - TCNQ), 777 (M+ - PPh3), 571 (M+ - TCNQ, PPh3).
Anal. Calcd for C64H48N4P2Ru: C, 74.19; H, 4.67; N, 5.41. Found:
C, 74.35; H, 4.89; N, 5.63.
Reaction of 6b with MeOH/n-Bu4NOH. To a solution of 6b (0.506
g, 0.48 mmol in 10 mL of acetone) was added 2.5 mL of CH3OH/(n-
Bu)4NOH. The color of the solution immediately changed to dark-
green with the formation of light yellow precipitate. The solution was
further stirred at room temperature for 40 min and then was filtered.
The precipitate was washed with 3 × 20 mL of methanol to give the
yellow product. Recrystallization from a mixture of 1:1 CH2Cl2/CH3-
Reaction of 2f with n-BuN4F. To a solution of 2f (0.35 g, 0.29
mmol) in 10 mL of acetone, was added a 3.5-mL solution of n-Bu4NF.
After for 48 h, the light yellow microcrystals formed and were filtered
and washed with 2 × 10 mL of diethyl ether and then dried under
vacuum. Recrystallization from CHCl3 yielded [Ru]-CdC(Ph)C(CN)-
CPh3 (3f) (0.12 g, 0.11 mmol, 38% yield). Spectroscopic data for 3f:
1H NMR CDCl3: 7.79-5.47 (m, 50H, Ph); 4.29 (s, 5H, Cp). 13C NMR
CDCl3: 142.0-125.0 (Ph); 121.1 (CN); 84.6 (Cp); 62.1 (CPh3); 37.5
(CCN). 31P NMR CDCl3: 47.0, 46.7 (d, JP-P ) 35.6 Hz). MS FAB
m/z: 1077 (M+ + 1), 814 (M+ - PPh3), 693 (M+ - C3Ph(CN)CPh3).
Anal. Calcd for C70H55NP2Ru: C, 78.34; H, 5.17; N, 1.31. Found:
C, 78.67; H, 5.15; N, 1.72.
CN gave [Ru]-CdC(Ph)C(CN)OMe (9b) (0.366 g, 0.43 mmol, 88%
yield). Spectroscopic data for 9b: 1H NMR, CDCl3: 7.25-6.64 (m,
35H, Ph); 4.66 (s, 5H, Cp); 3.44 (s, 3H, Me). 13C NMR, CDCl3: 136.2
(t, JP-C ) 19.8 Hz, CR); 139.7-127.4 (Ph); 109.4 (CN); 86.3 (Cp);
59.3 (C(CN)(OMe)); 55.8 (OMe). 31P NMR, CDCl3: 51.7, 4.96 (two
d, JP-P ) 36.0 Hz). MS FAB m/z: 863 (M+), 848 (M+ - Me), 832
(M+ - OMe), 693 (M+ - cyclopropenyl moiety), 601 (M+ - PPh3),
431 (M+ - PPh3, cyclopropenyl moiety). Anal. Calcd for C52H43-
NOP2Ru: C, 72.54; H, 5.03; N, 1.63. Found: C, 73.07; H, 5.06; N,
1.56.
Reaction of 9b with CF3COOH. To a solution of 9b (0.078 g,
0.091 mmol in 2 mL of CH2Cl2) was added 2.5 µL of CF3COOH. The
color of the solution immediately changed from yellow to amber-red.
The solution was stirred at room temperature for 20 min and then 30
mL of hexane was added. The orange precipitate thus formed was
filtered and then washed with 2 × 5 mL of hexane to give the product
identified as [[Ru]-CC(Ph)C(CN)][CF3COO] (10b) (0.067 g, 0.071
mmol, 78% yield). Spectroscopic data for 10b: 1H NMR, CDCl3:
8.15-6.91 (m, 35H, Ph); 4.91 (s, 5H, Cp). 13C NMR, CDCl3: 213.0
(t, JP-C ) 17.2 Hz, CR); 183.1 (C(CN)); 162.2 (q, JC-F ) 43.0 Hz,
CO); 138.0-127.6 (Ph); 121.6 (CN); 114.3 (q, JC-F ) 282.0 Hz, CF3);
107.9 (CPh), 90.1 (Cp). 31P NMR, CDCl3: 46.8 (s). MS FAB m/z:
848 (M+ + O - CF3COO), 832 (M+), 693 (M+ - cyclopropenylium),
431 (M+ - PPh3, cyclopropenylium). Anal. Calcd for C53H40-
F3NO2P2Ru: C, 67.51; H, 4.28; N, 1.49. Found: C, 67.44; H, 4.45;
N, 1.60. Complex 10b is ether sensitive.
Reaction of Complex 2j with n-Bu4NF. The synthesis and workup
were similar to those used in the preparation of complex 4h, but a
solution of 2j (0.34 g, 0.35 mmol) in 10 mL of acetone and a solution
of n-Bu4NF (4 mL) were used yielding [Ru]-CFdC(Ph)CH2OCH3 (5)
(0.24 g, 0.28 mmol, 80% yield). Spectroscopic data for 5: 1H NMR
-40 °C, CDCl3: 7.47-6.88 (Ph); 4.00 (br, s, 2H, CH2); 3.78 (s, 5H,
Cp); 3.05 (s, 3H, CH3). 13C NMR -40 °C, CDCl3: 133.4-125.8 (Ph);
84.3 (Cp); 70.8 (d, JC-F ) 21.8 Hz, CH2); 55.4 (CH3). 31P NMR -40
°C, CDCl3: 50.2 (d, JP-F ) 47.0 Hz). MS FAB m/z: 858 (M+), 839
(M+ - F), 794 (M+ - F, CH2OMe), 631 (M+ - C2FPhCH2OMe),
431 (M+ - PPh3, C2FPhCH2OMe). Only one of the E,Z-isomers was
obtained and the spectroscopic data are not sufficient to identify the
configuration. No reaction was observed when 2j was treated with
(n-Bu)4NOH or DBU.
Reaction of 3b with TCNQ. To a mixture of 3b (0.934 g, 1.12
mmol) and TCNQ (0.234 g, 1.15 mmol) was added under nitrogen 20
mL of CH2Cl2. The solution was stirred at room temperature for 20
min and then the solvent was removed under vacuum. The residue
was washed with 3 × 20 mL of methanol to produce the light orange
microcrystals identified as [Ru]dCdC(Ph)CH(CN)TCNQ (6b) (1.04
g, 1.01 mmol, 90% yield). Spectroscopic data for 6b: 1H NMR,
CDCl3: 7.50-6.77 (m, 39H, Ph); 5.24 (s, 5H, Cp); 3.32 (s, 1H, CH).
13C NMR, CDCl3: 336.8 (t, JP-C ) 14.7 Hz, CR); 146.2-119.4 (Ph);
123.3, 123.0, 114.8, 113.9, 113.3, 111.4 (5 CN and Câ); 95.8 (Cp);
45.1, 31.4 (2 C(CN)2); 39.2 (CHCN). 31P NMR, CDCl3: 40.6, 38.8
Synthesis of [Ru]-CdC(Ph)C(OMe)CO2Me (9h). To a suspen-
sion of 6h (0.210 g, 0.197 mmol) in 10 mL of acetone was added (n-
Bu)4NOH (1.0 mL) and the color turned to yellow immediately. The
solution was stirred at room temperature for 30 min. Unlike reactions
leading to cyclopropenyl complexes, this one did not yield any
precipitate. The solvent was thus removed under vacuum, the residue
was extracted with 2 × 15 mL of hexane, then the solution was dried
under vacuum to give 9h (0.105 g, 60% yield). Spectroscopic data
for 9h: 1H NMR CDCl3: 7.50-6.22 (m, 35 H, Ph); 4.56 (s, 5H, Cp);
3.63 (s, 3H, CO2CH3); 3.29 (s, 3H, OCH3). 13C NMR CDCl3: 179.7
(s, COO); 140.9-125.2 (Ph); 85.8 (Cp); 55.3 (OMe); 53.9 (Câ sp3);
51.2 (CO2CH3). 31P NMR CDCl3: 53.6 (d, JP-P ) 34.8 Hz), 48.0 (d,
JP-P ) 34.8 Hz). MS FAB m/z: 896 (M+), 880 (M+ - O), 693 (M+
- cyclopropenyl moiety), 633 (M+ - PPh3).
(two d, JP-P ) 26.6 Hz). MS FAB m/z: 1038 (M+ + 1), 833 (M+
-
TCNQ), 571 (M+ - PPh3, TCNQ), 431 (M+ - PPh3, vinylidene). Anal.
Calcd for C63H45N5P2Ru: C, 73.10; H, 4.38; N, 6.77. Found: C, 73.23;
H, 4.76; N, 6.54.
Synthesis of [Ru]dCdC(Ph)CH(TCNQ)CO2Me (6h). The pro-
cedure used for the synthesis of 6h is similar to that used for 6b. The
yield of the orange complex 6h (0.408 g, 0.382 mmol) from the reaction
of 4h (0.375 g, 0.434 mmol) and TCNQ (0.090 g, 0.44 mmol) is 88%.
Spectroscopic data for 6h: 1H NMR CDCl3: 7.46-6.84 (m, 39 H,
Ph); 5.09 (s, 5H, Cp); 3.70 (s, 4H, CO2CH3 and CH). 13C NMR
CDCl3: 340.1 (t, JP-C ) 15.1 Hz, CR); 168.1 (CO2Me); 145.6-119.3
(Ph); 126.1, 124.4, 115.8, 114.9, 113.6 (Câ and CN); 95.6 (Cp); 53.0
(CO2CH3); 49.5, 31.0 (2C(CN)2); 43.1 (CHCO2Me). 31P NMR
CDCl3: 40.0, 38.7 (two d, JP-P ) 25.3 Hz). MS FAB m/z: 1071 (M+
+ 1), 866 (M+ - TCNQ), 604 (M+ - TCNQ, PPh3), 431 (M+ - PPh3,
vinylidene). Anal. Calcd for C64H48N4O2P2Ru: C, 71.97; H, 4.53; N,
5.25. Found: C, 72.11; H, 4.39; N, 5.42.
Synthesis of [[Ru]-CC(Ph)CCO2Me][CF3COO] (10h). Complex
9h (0.210 g, 0.197 mmol) was dissolved in 20 mL of CHCl3 and excess
CF3COOH was added. The color of the solution changed from yellow
to orange. After 1 h, the solvent was removed under vacuum and the
residue was washed with 2 × 20 mL of hexane to yield the orange
product 10h (0.209 g, 92%). Spectroscopic data for 10h: 1H NMR
CDCl3: 7.91-6.91 (m, 35 H, Ph); 4.75 (s, 5H, Cp); 3.80 (s, 3H, CO2-
Me). 13C NMR CDCl3: 213.6 (br, CR); 182.4, 175.6 (COO and
CCOO); 135.0-118.2 (Ph); 112.5 (CâPh); 89.3 (Cp); 53.8 (CH3). 31P
NMR CDCl3: 47.6. MS FAB m/z: 881 (M+ + O), 865 (M+), 693
(M+ - cyclopropenyl moiety). Anal. Calcd for C54H43F3O4P2Ru: C,
66.46; H, 4.44. Found: C, 66.28; H, 4.32.
Reaction of 10b with MeONa in THF. To a solution of 10b (0.016
g, 0.017 mmol in 2 mL THF) was added a small amount of CH3ONa
(0.005 g). The solution was stirred at room temperature for 30 min
and then the solvent was removed under vacuum. The residue was
extracted with CHCl3 and solvent removed under vacuum to give [Ru]-
Synthesis of [Ru]dCdC(Ph)CHdCHCH2TCNQ (7d). To a
mixture of 3d (0.241 g, 0.29 mmol) and TCNQ (0.059 g, 0.29 mmol)
at -40 °C was added 10 mL of CH2Cl2. The solution was stirred at
-40 °C for 10 min and then the solvent was removed under vacuum.
The residue was first washed with 2 × 20 mL of methanol and then
dried under vacuum to give the brown product identified as 7d (0.161
g, 0.16 mmol, 54% yield). Spectroscopic data for 7d: 1H NMR
CDCl3: 7.44-6.80 (m, 39 H, Ph); 5.49 (d, 1H, JH-H ) 15.1 Hz, dCH);
5.11 (s, 5H, Cp); 4.61 (m, 1H, dCH); 2.64 (d, 2H, JH-H ) 7.54 Hz,

6444 J. Am. Chem. Soc., Vol. 118, No. 27, 1996
Ting et al.
4.87 (s, 10H, Cp). 13C NMR CDCl3: 140.1-126.2 (Ph); 124.6 (CN);
85.6 (Cp); 30.4 (CCN). 31P NMR CDCl3: 49.7, 48.5 (d, JP-P ) 36.4
C(OMe)C(Ph)dC(CN) (8b) (0.013 g, 0.015 mmol, 88% yield).
Spectroscopic data for 8b: 1H NMR, CDCl3: 7.28-6.63 (m, 35H, Ph);
4.50 (s, 5H, Cp); 3.29 (s, 3H, Me). 31P NMR, CDCl3: 51.2, 50.7 (two
d, JP-P ) 29.6 Hz). Complex 8b in acetone is unstable and readily
converts to 9b quantitatively, but is stable in THF and CHCl3.
Hz). MS FAB, m/e: 1665 (M+), 1402 (M+ - PPh3), 1140 (M+
-
2PPh3). Anal. Calcd for C102H80N2P4Ru2: C, 73.81; H, 4.86; N, 1.69.
Found: C, 73.52; H, 4.72; N, 1.83.
X-ray Analysis of 3b, 3f, 4h, 6b, 9b, and 11. Single crystals of
3b suitable for an X-ray diffraction study were grown as mentioned
above. A single crystal of dimensions 0.40 × 0.40 × 0.45 mm3 was
glued to a glass fiber and mounted on an Enraf-Nonius CAD4
diffractometer. Initial lattice parameters were determined from a least-
squares fit to 25 accurately centered reflections with 10.0° < 2θ <
25°. Cell constants and other pertinent data are collected in the
supporting information. Data were collected using the θ/2θ scan
method. The final scan speed for each reflection was determined from
the net intensity gathered during an initial prescan and ranged from 2
to 7 deg min-1. The scan angle was determined for each reflection
according to the equation 0.8 + 0.35 tan θ.
The raw intensity data were converted to structure factor amplitudes
and their esd’s by correction for scan speed, background, and Lorentz,
polarization effects. An empirical correction for absorption based on
the azimuthal scan was applied to the data set. Crystallographic
computations were carried out on a Microvax III computer using the
NRCC structure determination package.57 Merging of equivalent and
duplicate reflections gave a total of 5194 unique measured data from
which 4106 were considered observed, I > 2.0σ(I). The structure was
first solved by using the heavy atom method (Patterson synthesis) which
revealed the position of metal, then refined via standard least-squares
and difference Fourier techniques. The quantity minimized by the least-
squares program was w([Fo| - |Fc|)2. The analytical forms of the
scattering factor tables for the neutral atoms were used.58 All other
non-hydrogen atoms were refined by using anisotropic thermal
parameters. Hydrogen atoms were included in the structure factor
calculations in their expected positions on the basis of idealized bonding
geometry but were not refined in least squares. Final refinement using
full-matrix, least-squares converged smoothly to values of R ) 0.040
and Rw ) 0.034. Final values of all refined atomic positional parameters
(with esd’s) and tables of thermal parameters are given in the supporting
information.
Synthesis of [Ru]-CdC(Ph)C(CN)2 (3m). Complex 6b (0.250
g, 0.24 mmol) was dissolved in 10 mL of acetone and a solution of
(n-Bu)4NCN (0.201 g in 5 mL of MeOH) was added at room
temperature. The solution was stirred for 2 h and the yellow precipitate
thus formed was filtered and washed with 2 × 10 mL of MeOH to
give the product 3m. Spectroscopic data for 3m: 1H NMR CDCl3:
7.23-6.60 (m, 35 H, Ph); 4.75 (s, 5H, Cp). 13C NMR CDCl3: 138.9-
126.8 (Ph); 123.2 (CN); 86.7 (Cp); 7.89 (C(CN)2). 31P NMR CDCl3:
48.3. MS FAB m/z: 859 (M+), 693 (M+ - C2PhC(CN)2), 596 (M+
-
PPh3). Anal. Calcd for C52H40N2P2Ru: C, 72.97; H, 4.71; N, 3.27.
Found: C, 73.15; H, 4.89; N, 3.46.
Synthesis of [[Ru]dCdC(Ph)C(CN)2H][CF3COO] (2m). Com-
plex 3m (0.080 g, 0.093 mmol) was dissolved in 0.5 mL of CDCl3 and
CF3COOH (0.03 mL) was added. The solvent was removed under
vacuum and the product washed with hexane was identified as 2m.
Spectroscopic data for 2m: 1H NMR CDCl3: 7.52-6.85 (m, 35 H,
Ph); 5.25 (s, 5H, Cp); 4.08 (s, 1H, C(CN)2H). 13C NMR CDCl3: 336.3
(br, CR); 162.2 (q, JF-C ) 43.0 Hz, CF3COO); 135.8-121.5 (Ph); 121.0
(Câ); 118.6 (CN); 114.3 (q, JF-C ) 282.0 Hz, CF3); 96.2 (Cp); 19.7
(C(CN)2). 31P NMR CDCl3: 39.4. MS FAB m/z: 859 (M+), 693 (M+
- C2PhC3N2H), 596 (M+ - PPh3). Anal. Calcd for C54H41-
F3N2O2P2Ru: C, 66.87; H, 4.26; N, 2.89. Found: C, 66.59; H, 3.97;
N, 2.96. Complex 2m was converted back to 3m by (n-Bu)4NOH/
MeOH solution in quantitative NMR yield.
Dimerization of 3b in the Presence of Allyl Iodide. Excess freshly
distilled allyl iodide (0.65 mL, 7.1 mmol) was added to a solution of
3b (0.31 g, 0.37 mmol) in 10 mL of CHCl3. This mixture was stirred
at room temperature for 48 h to give orange red precipitate which was
filtered off, washed with 20 mL of CHCl3 and 2 × 10 mL of hexane,
then dried in vacuo yielding [[Ru]dCdC(Ph)CH(CN)]2I6 (11) (0.44
g, 0.18 mmol, 49% yield). 11 is insoluble in common organic solvents
except DMSO. Spectroscopic data for 11: 1H NMR d6-DMSO: 7.57-
6.59 (m, 70H, Ph); 5.34 (s, 10H, Cp); 3.51 (s, 2H, CH). 13C NMR
d6-DMSO: 354.3 (t, CR); 132.9-123.2 (Ph); 120.7 (Câ); 116.5 (CN);
95.6 (Cp); 32.5 (CH). 31P NMR d6-DMSO: 42.3, 41.3 (d, JP-P ) 26.7
Hz). MS FAB m/z: 1792 (M+ + I), 1531 (M+ + 1 - PPh3), 1271
(M+ + 1 - 2PPh3), 1142 (M+ - 2PPh3). Anal. Calcd for C102H82N2P4-
Ru2I6 (I6 salt from recrystallization): C, 50.55; H, 3.41; N, 1.15.
Found: C, 51.01; H, 3.11; N, 1.42.
The procedures for 3f, 4h, 6b, 9b, and 11 were similar. The final
residuls of the refinement were R ) 0.070, Rw ) 0.066 for 3f; R )
0.061, Rw ) 0.068 for 4h; R ) 0.073, Rw ) 0.075 for 6b; R ) 0.033,
Rw ) 0.034 for 9b; and R ) 0.062, Rw ) 0.042 for 11. Final values
of all refined atomic positional parameters (with esd’s) and tables of
thermal parameters are given in the supporting information.
Proton Abstraction of 11. To a suspension of 11 (0.15 g, .062
mmol) in 5 mL of acetone was added (n-Bu)4NOH (1.0 mL) and yellow
precipitate formed immediately. The precipitate was filtered and
washed with 2 × 5 mL of acetone then dried under vacuum. This
complex was identified as [[Ru]-CdC(Ph)C(CN)]2 (12) (0.082 g, 0.049
mmol, 80% yield) based on its spectroscopic data and mass spectrum.
Spectroscopic data for 12: 1H NMR CDCl3: 7.47-6.40 (m, 70H, Ph);
Acknowledgment. We are grateful for support of this work
by the National Science Council, Taiwan, Republic of China.
Supporting Information Available: Details of the structural
determination for complexes 3b, 3f, 4h, 6b, 9b, and 11 including
tables of crystal data and structure refinement, positional and
anisotropic thermal parameters, and listings of bond distances
and angles (49 pages). See any current masthead page for
ordering and Internet access instructions.
(57) Gabe, E. J.; Lee, F. L.; Lepage, Y. In Crystallographic Computing
3; Sheldrick, G. M., Kruger, C., Goddard, R., Eds.; Clarendon Press:
Oxford, England, 1985; p 167.
(58) International Tables for X-ray Crystallography; Reidel Publishing
Co.: Dordrecht, Boston, 1974; Vol. IV.
JA960001K