Reaction of Tp(PPh3)Ru(η2-O2CCHPh2) with carbene and vinylidene precursors

Article abstract of DOI:10.1021/om010558v

Tp(PPh₃)Ru(η²-O₂CCHPh₂) (1) [Tp = tris(pyrazolyl)borate] has been prepared by the reaction of TpRu(Cl)(PPh₃)₂ with 1.2 equiv of NaO₂CCHPh₂. Complex 1 reacts with diphe

Full text of DOI:10.1021/om010558v

Organometallics 2001, 20, 5455-5463
5455
Rea ction of Tp (P P h 3)Ru (η2-O2CCHP h 2) w ith Ca r ben e a n d
Vin ylid en e P r ecu r sor s
Melanie S. Sanford, Michelle R. Valdez, and Robert H. Grubbs*
Arnold and Mabel Beckman Laboratories for Chemical Synthesis, Division of Chemistry and
Chemical Engineering, California Institute of Technology, Pasadena, California 91125
Received J une 25, 2001
Tp(PPh3)Ru(η2-O2CCHPh2) (1) [Tp ) tris(pyrazolyl)borate] has been prepared by the
reaction of TpRu(Cl)(PPh3)2 with 1.2 equiv of NaO2CCHPh2. Complex 1 reacts with
diphenylcyclopropene to generate the metallacycle Tp(PPh3)Ru[κ2-(C,Ã)-C(dCHCHPh2)OC-
(CHPh2)dO] (2). A trace of the carbene Tp(PPh3)(η1-O2CCHPh2)RudCHCHdC(Ph)2 (3) is
also observed in the crude reaction mixture. Compound 1 reacts with phenyldiazomethane
to form the benzylidene Tp(PPh3)(η1-O2CCHPh2)RudCHPh (4). A similar species is also
available by the reaction between AgO2CCHPh2 and Tp(PCy3)(Cl)RudCHCHdC(CH3)2 (5),
which affords Tp(PCy3)(η1-O2CCHPh2)RudCHCHdC(CH3)2 (6). With the addition of an excess
of HCl, complexes 4 and 6 release free HO2CCHPh2 and are converted to Tp(PPh3)(Cl)Rud
CHPh (7) and complex 5, respectively. The reaction of 1 with phenylacetylene yields the
five-membered chelate Tp(PPh3)Ru[κ2-(C,Ã)-C(dCHPh)OC(CHPh2)dO] (8). Complex 8 is also
formed in the reaction of Tp(PPh3)(Cl)RudCdCHPh with 1.2 equiv of AgO2CCHPh2.
Compounds 1, 2, and 8 have been characterized by X-ray crystallography. Complexes 2, 5,
6, 7, and 8 do not catalyze olefin metathesis reactions, while 4 is an active initiator for the
ring-opening metathesis polymerization of norbornene.
In tr od u ction
to our ongoing research program involving the prepara-
tion of new ruthenium carbene complexes for applica-
tions in olefin metathesis,11 we became interested in the
reactions of carbene precursors with Tp[Ru] fragments.
Our group and others have reported that cyclopropene
derivatives,12 diazo compounds,13,14 and terminal
alkynes2,3,15 can react with transition metals to generate
Tris(pyrazolyl)borate ruthenium complexes have been
well studied over the past five years.1 A wide variety of
Tp[Ru] species containing ruthenium-carbon bonds
including vinylidene,2-4 allenylidene,2,5 alkylidene,5,6
and alkyl7 ligands have been prepared, and these
compounds have proven useful for carbon-carbon bond
forming reactions including alkyne-alkyne3a,8 and
alkyne-olefin9 couplings and olefin metathesis.6,10 Due
(8) (a) Pavlik, S.; Gemel, C.; Slugovc, C.; Mereiter, K.; Schmid, R.;
Kirchner, K. J . Organomet. Chem. 2001, 617, 301. (b) Slugovc, C.;
Mauthner, K.; Kacetl; Mereiter, K.; Schmid, R.; Kirchner, K. Chem.
Eur. J . 1998, 4, 2043. (c) Slugovc, C.; Doberer, D.; Gemel, C.; Schmid,
R.; Kirchner, K.; Winkler, B.; Stelzer, F. Monatsh. Chem. 1998, 129,
221. (d) Slugovc, C.; Mereiter, K.; Zobetz, E.; Schmid, R.; Kirchner, K.
Organometallics 1996, 15, 5275.
(9) (a) Slugovc, C.; Mereiter, K.; Schmid, R., Kirchner, K. Eur. J .
Inorg. Chem. 1999, 1141. (b) Slugovc, C.; Mereiter, K.; Schmid, R.,
Kirchner, K. J . Am. Chem. Soc. 1998, 120, 6175.
(1) For a recent review see: Slugovc, C.; Schmid, R.; Kirchner, K.
Coord. Chem. Rev. 1999, 186, 109.
(2) (a) Buriez, B.; Cook, D. J .; Harlow, K. J .; Hill, A. F.; Welton, T.;
White, A. J . P.; Williams, D. J .; Wilton-Ely, J . D. E. T. J . Organomet.
Chem. 1999, 578, 264. (b) Buriez, B.; Burns, I. D.; Hill, A. F.; White,
A. J . P.; Williams, D. J .; Wilton-Ely, J . D. E. T. Organometallics 1999,
18, 1504.
(3) (a) Tenorio, M. A. J .; Tenorio, M. J .; Puerta, M. C.; Valerga, P.
Organometallics 2000, 19, 1333. (b) Tenorio, M. A. J .; Tenorio, M. J .;
Puerta, M. C.; Valerga, P. Organometallics 1997, 16, 5528.
(4) (a) Slugovc, C.; Gemel, C.; Shen, J . Y.; Doberer, D.; Schmid, R.;
Kirchner, K.; Mereiter, K. Monatsh. Chem. 1999, 130, 363. (b) Ruba,
E.; Gemel, C.; Slugovc, C.; Mereiter, K.; Schmid, R.; Kirchner, K.
Organometallics 1999, 18, 2275. (c) Slugovc, C.; Mereiter, K.; Schmid,
R.; Kirchner, K. Organometallics 1998, 17, 827. (d) Slugovc, C.;
Sapunov, V. N.; Wiede, P.; Mereiter, K.; Schmid, R.; Kirchner, K. J .
Chem. Soc., Dalton Trans. 1997, 4209. (e) Gemel, C.; Kickelbick, G.;
Schmid, R.; Kirchner, K. J . Chem. Soc., Dalton Trans. 1997, 2113. (f)
Trimmel, G.; Slugovc, C.; Wiede, P.; Mereiter, K.; Sapunov, V. N.;
Schmid, R.; Kirchner, K. Inorg. Chem. 1997, 36, 1076. (g) Gemel, C.;
Wiede, P.; Mereiter, K.; Sapunov, V. N.; Schmid, R.; Kirchner, K. J .
Chem. Soc., Dalton Trans. 1996, 4071.
(10) Katayama, H.; Yoshida, T.; Ozawa, F. J . Organomet. Chem.
1998, 562, 203.
(11) (a) Scholl, M.; Ding, S.; Lee, C. W.; Grubbs, R. H. Org. Lett.
1999, 1, 953. (b) Scholl, M.; Trnka, T. M.; Morgan, J . P.; Grubbs, R. H.
Tetrahedron Lett. 1999, 40, 2247. (c) Chang, S.; J ones, L.; Wang, C.
M.; Henling, L. M.; Grubbs, R. H. Organometallics 1998, 17, 3460. (d)
Dias, E. L.; Grubbs, R. H. Organometallics 1998, 17, 2758.
(12) Some examples of the ring opening of cyclopropenes at transi-
tion metal centers include: (a) Nguyen, S. T.; Grubbs, R. H.; Ziller, J .
W. J . Am. Chem. Soc. 1993, 115, 9858. (b) J ohnson, L. K.; Grubbs, R.
H.; Ziller, J . W. J . Am. Chem. Soc. 1993, 115, 8130. (c) Nguyen, S. T.;
J ohnson, L. K.; Grubbs, R. H. J . Am. Chem. Soc. 1992, 114, 3974. (d)
Binger, P.; Muller, P.; Benn, R.; Mynott, R. Angew. Chem., Int. Ed.
Engl. 1989, 28, 610.
(13) (a) Schwab, P.; Grubbs, R. H.; Ziller, J . W. J . Am. Chem Soc.
1996, 118, 100. (b) Schwab, P.; France, M. B.; Grubbs, R. H.; Ziller, J .
W. Angew. Chem., Int. Ed. Engl. 1995, 34, 2039.
(5) (a) Harlow, K. J .; Hill, A. F.; Wilton-Ely, J . D. E. T. J . Chem.
Soc., Dalton Trans. 1999, 285.
(6) Sanford, M. S.; Henling, L. M.; Grubbs, R. H. Organometallics
1998, 17, 5385.
(14) Some recent examples of the preparation of metal alkylidenes
from diazo compounds from other groups include: (a) Lee, H. M.;
Bianchini, C.; J ia, G. C.; Barbaro, P. Organometallics 1999, 18, 1961.
(b) Ortmann, D. A.; Weberndorfer, B.; Schoneboom, J .; Werner, H.
Organometallics 1999, 18, 952. (c) Galardon, E.; Le Maux, P.; Toupet,
L.; Simonneaux, G. Organometallics 1998, 17, 565. (d) Werner, H.;
Schwab, P.; Bleuel, E.; Mahr, N.; Steinert, P.; Wolf, J . Chem. Eur. J .
1997, 3, 1375.
(7) (a) Lo, Y. H.; Lin, Y. C.; Lee, G. H.; Wang, Y. Organometallics
1999, 18, 982. (b) Chen, Y. Z.; Chan, W. C.; Lau, C. P.; Chu, H. S.;
Lee, H. L. Organometallics 1997, 16, 1241. (c) Maruyama, Y.; Ikeda,
S.; Ozawa, F. Bull. Chem. Soc. J pn. 1997, 70, 689. (d) Corrochano, A.
E.; J aoln, F. A.; Otero, A.; Kubicki, M. M.; Richard, P. Organometallics
1997, 16, 145.
10.1021/om010558v CCC: $20.00 © 2001 American Chemical Society
Publication on Web 11/06/2001

5456 Organometallics, Vol. 20, No. 25, 2001
Sanford et al.
Sch em e 1
alkylidene and vinylidene complexes. The use of alkynes
for the preparation of Tp[Ru] vinylidenes has been well
explored by a number of groups.2-4 However, the
reaction of Tp[Ru] complexes with cyclopropenes or
diazo compounds has not been described in the litera-
ture.
We report here the first example of an isolable Tp-
[Ru] η2-carboxylate complex, Τp(PPh3)Ru(η2-O2CCHPh2)
(1) (Scheme 1). This compound reacts cleanly with
several carbene precursors to form new ruthenium-
carbon bonds where the carboxylate shifts from η2 to η1
coordination and, in some cases, couples to the incoming
ligand. For example, the reaction of 1 with diphenylcy-
clopropene results in the generation of the five-mem-
bered chelate Tp(PPh3)Ru[κ2-(C,O)-C(dCHCHPh2)OC-
(CHPh2)dO] (2) (Scheme 2). Complex 1 reacts with
phenylacetylene to produce the related metallacycle Tp-
(PPh3)Ru[κ2-(C,O)-C(dCHPh)OC(CHPh2)dO] (8) (Scheme
4). The η2-carboxylate complex also undergoes reaction
with phenyldiazomethane, yielding the new ruthenium
benzylidene Tp(PPh3)(η1-O2CCHPh2)RudCHPh (4)
(Scheme 3). This paper describes the synthesis and
characterization of these new compounds as well as
several related species. The olefin metathesis activities
of these Tp[Ru] complexes have also been preliminarily
explored.
F igu r e 1. Labeled view of complex 1 with 50% probability
ellipsoids.
frequencies in these otherwise similar complexes may
be due to the increased electron-donating ability of the
Tp ligand relative to the Cp ligand.17 The solid-state
structure of complex 1 was determined by X-ray crystal-
lography. Large orange-yellow crystals were grown by
vapor diffusion of pentane into a concentrated CH2Cl2
solution of 1 at room temperature. A labeled view of the
complex is shown in Figure 1, collection and refinement
data are summarized in Table 1, and selected bond
lengths and bond angles are reported in Table 2. The
Ru-O bond lengths in complex 1 are 2.1481(14) and
2.1631(16) Å. These distances are in the range of other
crystallographically characterized ruthenium η2-car-
boxylates, such as Cp(PPh3)Ru[η2-O2C(t-Bu)] (d(Ru-O)
) 2.200(3) and 2.202(4) Å),16 [(S)-BINAP]Ru[η2-O2C(t-
Bu)]2 (d(Ru-O) ) 2.216(8) and 2.137(6) Å),18 and
(PPh3)2(CO)(Cl)Ru(η2-O2CMe) (d(Ru-O) ) 2.152(6) and
2.144(6) Å).19 In general, the structure of 1 exhibits no
unusual features compared to these and other related
ruthenium adducts.
R ea ct ion of 1 w it h 3,3-Dip h en ylcyclop r op en e.
Complex 1 serves as a versatile starting material for
ruthenium-carbon bond forming reactions, because the
carboxylate ligand undergoes facile η2 to η1 intercon-
version to open up a coordination site at the metal
center. For example, complex 1 reacts slowly with
diphenylcyclopropene in toluene over 24 h to produce
the metallacyclic species Tp(PPh3)Ru[κ2-(C,O)-C(d
CHCHPh2)OC(CHPh2)dO] (2) in 48% isolated yield
(Scheme 2). Complex 2 is isolated as an orange powder
and forms light yellow crystals upon recrystallization
from toluene/pentane. This compound is air-stable
indefinitely in the solid state, but decomposes in air
when in solution to form an intractable dark red
mixture.
Resu lts a n d Discu ssion
Syn th esis of Tp (P P h 3)Ru (η2-O2CCHP h 2) (1). The
reaction of NaO2CCHPh2 with TpRu(Cl)(PPh3)2 for 24
h in refluxing THF results in clean displacement of one
chloride and one PPh3 ligand to afford Tp(PPh3)Ru(η2-
O2CCHPh2) (1) in 82% isolated yield (Scheme 1). In
contrast to the formyl complex Tp(PPh3)Ru(η2-O2CH),
which was reported by Hill and co-workers,2b complex
1 is thermally stable and is readily purified by recrys-
tallization from CH2Cl2/pentane.
The product is isolated as an air-stable light yellow
solid which is insoluble in pentane, slightly soluble in
benzene, and soluble in chlorinated solvents and THF.
1H NMR spectroscopy of complex 1 shows six resonances
for the pyrazolyl protons, indicating that the carboxylate
is bound to the metal center in a symmetrical η2 fashion.
The η2 binding mode is confirmed by IR spectroscopy,
which shows the OCO asymmetric stretch at 1526 cm-1
This value is slightly higher than that in Cp(PPh3)Ru-
.
[η2-O2C(t-Bu)] (1495 cm-1 16 and Cp(PPh3)Ru(η2-O2-
)
The 1H NMR spectrum of 2 shows nine separate
resonances for the pyrazolyl protons, indicating that the
metal is a stereogenic center. The protons attached to
the â- and γ-carbons appear as doublets (J HH ) 9 Hz)
CCH3) (1490 cm-1),16 and the difference in IR stretching
(15) Recent examples of the synthesis of metathesis-active ruthe-
nium olefin metathesis catalysts from alkynes include: (a) Wolf, J .;
Stuer, W.; Grunwald, C.; Werner, H.; Schwab, P.; Schulz, M. Angew.
Chem., Int. Ed. 1998, 37, 1124. (b) Wilhelm, T. E.; Brown, S. N.;
Belderrain, T. R.; Grubbs, R. H. Organometallics 1997, 16, 3867. (c)
Grunwald, C.; Gevert, O.; Wolf, J .; Gonzalez-Herrero, P.; Werner, H.
Organometallics 1996, 15, 1960.
(17) Sharp, P. R.; Bard, A. J . Inorg. Chem. 1983, 22, 2689.
(18) Ohta, T.; Takaya, H.; Noyori, R. Inorg. Chem. 1988, 27, 566.
(19) Sanchez-Delgado, R. A.; Thewalt, U.; Valencia, N.; Andriollo,
A.; Marquez-Silva, R.-L.; Puga, J .; Schollhorn, H.; Klein, H.-P.; Fontal,
B. Inorg. Chem. 1986, 25, 1097.
(16) Werner, H.; Braun, T.; Daniel, T.; Gevert, O.; Schulz, M. J .
Organomet. Chem. 1997, 541, 127.

Reaction of Tp(PPh3)Ru(η2-O2CCHPh2)
Organometallics, Vol. 20, No. 25, 2001 5457
Sch em e 2
Sch em e 3
at 5.42 and 4.81 ppm, respectively, and show no
coupling to the remote 31P nucleus. 13C NMR spectros-
copy of complex 2 shows CR as a doublet (J CP ) 17 Hz)
at 203.97 ppm and Câ as a singlet at 118.97 ppm. The
downfield shift of CR, as well as the observed carbon-
phosphorus coupling, indicate that this carbon is sp2
hybridized and is bound to the metal center. However,
this peak is significantly upfield of a typical Ru vi-
nylidene or alkylidene carbon resonance.20A small
amount of the analogous carbene complex Tp(PPh3)(η1-
O2CCHPh2)RudCHCHdC(Ph)2 (3) (<3%) is also ob-
characterized by any other spectroscopic methods due
to its low concentration in solution. Attempts to improve
the yield of complex 3 by changing the reaction condi-
tions (solvent, temperature, time) were unsuccessful,
and complexes 2 and 3 do not appear to interconvert
upon exposure to heat or UV irradiation.22 In general,
these data suggest that complexes 2 and 3 are formed
independently and that 3 is not an intermediate in the
generation of 2. Complex 3 is the product of a well-
precedented ring opening of diphenylcyclopropene at a
Ru(II) center.12 In contrast, the mechanism of formation
of 2 (which requires a formal 1,3-hydrogen shift within
the cyclopropene-derived fragment) is not well under-
stood at this time.23
1
served if this reaction is monitored by H NMR spec-
troscopy. The R-proton of the alkylidene appears as an
overlapping doublet of doublets (apparent triplet) at
18.56 ppm.21 Unfortunately, this product could not be
(21) Proton NMR shifts between 18 and 21 ppm are typical of
ruthenium alkylidenes. For examples see ref 5.
(22) After 2 days at 45 °C both species decompose entirely. The
identity of the multiple decomposition products is unknown at this
time.
(20) Carbon-13 NMR shifts between 350 and 300 ppm are typical
of ruthenium vinylidenes (for examples see ref 2 and ref 3) and
alkylidenes (for example see ref 5).

5458 Organometallics, Vol. 20, No. 25, 2001
Sanford et al.
Sch em e 4
Ta ble 1. X-r a y Exp er im en ta l Da ta
1‚CH2Cl2
42H38BCl2N6O2PRu-
[C41H36BN6O2PRu‚CH2Cl2]
2‚1/3(C5H12)‚1/6(C7H8)
8‚1/2(CH2Cl2)
formula
fw
C
C58.83H53.33BN6O2PRu-
[C56H48BN6O2PRu‚1/3 (C5H12)‚
1/6(C7H8)]
1019.26 [979.89 ×
1/3(72.15) × 1/6(92.14)]
triclinic
C49.50H43BClN6O2PRu-
[C49H42BN6O2PRu‚1/2(CH2Cl2)]
872.56
932.23
[787.63 × 84.93]
monoclinic
P21/c (# 14)
15.112(3)
14.287(3)
19.039(4)
90
105.32(3)
90
3964.6(14)
4
[889.77 × 1/2 (84.93)]
cryst syst
space group
a, Å
b, Å
c, Å
triclinic
P1h (# 2)
P1h (# 2)
14.146(5)
21.309(8)
25.345(8)
84.57(3)
15.573(4)
18.179(7)
18.245(5)
98.75(3)
113.89(2)
105.27(2)
4355(2)
R, deg
â, deg
γ, deg
volume, Å3
Z
79.86(3)
87.45(3)
7484(5)
6
4
F
calc, g/cm3
1.462
0.62
1784
1.357
1.422
0.51
1916
µ, mm-1
0.40
F000
3170
cryst shape
cryst color
cryst size, mm
T, K
plate
yellow
wedge
wedge
yellow
canary yellow
0.11 × 0.33 × 0.44
84
0.07 × 0.28 × 0.35
0.20 × 0.25 × 0.44
84
84
θ range, γ
h,k,l limits
no. of data measd
no. of unique data
1.8, 25.0
0, 17; -16, 16; -22, 22
15 540
6953
0.016
1.5, 25.0
-16, 16; -25, 25; -29, 30
53 947
26 257
0.031
1.5, 25.0
-18, 18; -21, 21; -21, 21
31 982
15 315
0.024
b
Rint
data, Fo>4σ(Fo)
no. of params/restraints
R1,wR2; all data
R1,wR2; Fo>4σ(Fo)
GOF on F2
6231
703/0
0.032, 0.060
0.026, 0.058
1.78
21 442
2302/12
0.057, 0.082
0.041, 0.078
1.57
13 208
1360/0
0.044, 0.074
0.035, 0.072
1.70
∆Fmax,min, e Å-3
0.39, -0.41
1.54, -1.06
1.52, -1.23
a
b
2
All data were collected on a CAD-4 diffractometer with graphite-monochromated Mo KR radiation (λ ) 0.71073 Å). Rint ) ∑|∆Fo |/
∑2[Fo2] for reflections measured exactly twice with each Fo > 0.
The structure of complex 2 was confirmed by X-ray
crystallography. Suitable crystals were grown by vapor
diffusion of pentane into a concentrated toluene solution
at room temperature. A labeled view is shown in Figure
2, and the collection and refinement data are sum-
marized in Table 1. Complex 2 crystallizes with three

Reaction of Tp(PPh3)Ru(η2-O2CCHPh2)
Organometallics, Vol. 20, No. 25, 2001 5459
F igu r e 3. Tautomeric forms of complex 2.
Ta ble 3. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for Com p lex 2 (Molecu le A)
Bond Lengths
Ru-C(1)
Ru-N(1)
Ru-N(3)
Ru-N(5)
Ru-O(1)
2.005(3)
2.152(3)
2.052(3)
2.129(3)
2.098(2)
Ru-P
2.2820(12)
1.242(4)
1.302(4)
1.526(3)
1.327(4)
O(1)-C(16)
O(2)-C(16)
O(2)-C(1)
C(1)-C(2)
Bond Angles
91.67(9) O(1)-Ru-P
F igu r e 2. Labeled view of complex 2 with 50% probability
ellipsoids (phenyl groups on phosphine ligand omitted for
clarity).
N(1)-Ru-O(1)
N(3)-Ru-O(1)
N(5)-Ru-O(1)
N(1)-Ru-C(1)
N(3)-Ru-C(1)
96.28(6)
Ru-O(1)-C(16) 112.49(19)
171.63(9)
87.32(9)
Ru-C(1)-O(2)
169.05(10) Ru-C(1)-C(2)
97.51(11) N(5)-Ru-C(1)
108.64(18)
141.7(2)
87.06(11)
Ta ble 2. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for Com p lex 1
O(1)-C(16)-O(2) 123.1(3)
O(2)-C(1)-C(2) 108.8(3)
Bond Lengths
Ru-N(1)
Ru-N(2)
Ru-N(3)
Ru-P
2.0359(18)
2.0584(17)
2.1361(16)
2.2795(7)
Ru-O(1)
Ru-O(2)
O(1)-C(1)
O(2)-C(1)
2.1481(14)
2.1631(16)
1.271(2)
1.516 Å in complex 2 is much longer than a typical C-O
single bond. (For example, the CR-O bond length in Cp-
(CO)(PPh3)Ru-C(OiPr)dCHPh is 1.381(7) Å.)24 Ad-
ditionally, the average Ru-C(1)-C(2) angle is 140.6°,
while the average O(2)-C(1)-C(2) angle is 109.2°,
which are both significant distortions from the ideal sp2
angles of 120°. Taken together, these data reflect a
contribution of the tautomeric vinylidene (2a ) (Figure
3) to the solid-state structure of complex 2.26
1.263(2)
Bond Angles
N(1)-Ru-O(2)
N(3)-Ru-O(2)
N(2)-Ru-O(2)
N(1)-Ru-O(1)
N(3)-Ru-O(1)
N(2)-Ru-O(1)
103.44(6)
164.64(6)
87.98(6)
164.02(6)
105.26(6)
90.96(6)
O(2)-Ru-P
O(1)-Ru-P
O(2)-Ru-O(1)
C(1)-O(1)-Ru
C(1)-O(2)-Ru
O(2)-C(1)-O(1)
95.66(4)
92.55(4)
60.95(5)
89.44(12)
90.32(12)
119.26(19)
Rea ction of 1 w ith P h en yld ia zom eth a n e. Com-
plex 1 reacts with an excess of phenyldiazomethane to
generate Tp(PPh3)(η1-O2CCHPh2)RudCHPh (4) in 78%
yield (Scheme 3). The reaction can be followed by
observing a dramatic color change from light yellow to
dark green and is complete within 3 h. 1H and 13C NMR
spectroscopy clearly confirm the identity of complex 4
as a transition metal carbene and not its metallacyclic
tautomer 4a (Scheme 3). The R-proton of the carbene
appears as a doublet (J HP ) 15 Hz) at 19.06 ppm, while
the R-carbon appears as a doublet (J HP ) 11 Hz) at
339.63 ppm. Interestingly, a number of similar com-
pounds of the general formula Cp(PPh3)(η1-O2CR1)Ru-
(CR2) [R ) Ar; R1 ) CH3, tBu] have been reported,16 and
their 13C NMR spectra show no downfield resonance for
CR. As a result, the authors have suggested that these
complexes are better described as the tautomeric met-
allacycles Cp(PPh3)Ru[κ2-(C,O)-C(R)2OC(CR1)dO].16 This
is yet another example underlying the inherent reactiv-
ity differences between Cp[Ru] compounds and the
analogous Tp[Ru] species.27
independent molecules (which are very similar in struc-
ture) in the asymmetric unit, and the bond distances
and bond angles for molecule A are reported in Table
3. The average Ru-C(1) distance of 1.997 Å is inter-
mediate between that in the Ru(II) benzylidene [Tp-
(PCy3)(H2O)RudCHPh]BF4 (d(Ru-C) ) 1.878(4) Å)6
and that in the Ru(II) vinyl species Cp(CO)(PPh3)Ru-
C(OiPr)dCHPh (d(Ru-C) ) 2.130(6) Å).24 In related
compounds, Werner and co-workers have suggested that
this type of intermediate bond distance indicates sig-
nificant contribution of a zwitterionic alkylidene com-
plex (2b) (Figure 3) to the solid-state structure of the
metallacycle.25,26 The average C(1)-O(2) distance of
(23) Low-temperature 1H, 13C, or 31P NMR studies of this reaction
reveal that no long-lived intermediates are generated during the
formation of complex 2, and, with the exception of traces of carbene 3,
only starting material and product can be observed as the reaction
progresses. Several additional experiments provide preliminary in-
sights into the mechanism of this reaction. First, the rate of formation
of 2 is not affected by the addition of up to 10 equiv of free PPh3.
Second, the rate remains constant as the solvent is changed from C6D6
(ꢀ ) 2.3) to CD2Cl2 (ꢀ ) 8.9), which represents a significant change in
the dielectric constant of the reaction medium. The former result
indicates that phosphine dissociation is not required for this reaction
to proceed and suggests that the carboxylate ligand undergoes inter-
conversion between an η2 and an η1 geometry to generate an open
coordination site for olefin binding. The latter result suggests that
highly charged intermediates are not involved in the formation of 2.
Further investigations on this topic are ongoing.
A complex similar to 4 can also be prepared by the
reaction of 1.2 equiv of AgO2CCHPh2 with Tp(PCy3)-
(Cl)RudCHCHdC(CH3)2 (5) (Scheme 3). This reaction
proceeds instantaneously to afford Tp(PCy3)(η1-O2-
CCHPh2)RudCHCHdC(CH3)2 (6) in 61% isolated yield.
(26) In solution, the chemical shift of the R-carbon of complex 2 is
more consistent with its formulation as a ruthenium vinyl adduct than
as the tautomeric alkylidene or vinylidene structures [ref 24].
(27) For a review of the unique chemistry of the Tp ligand see:
Trofimenko, S. Chem. Rev. 1993, 93, 943.
(24) Bruce, M. I.; Duffy, D. N.; Humphrey, M. G.; Swincer, A. G. J .
Organomet. Chem. 1985, 282, 383.
(25) Daniel, T.; Mahr, N.; Braun, T.; Werner, H. Organometallics
1993, 12, 1475.

5460 Organometallics, Vol. 20, No. 25, 2001
Sanford et al.
Again, 1H and 13C NMR spectroscopy verify the identity
of this complex as a transition metal alkylidene and not
a metallacyclic species. The R-proton appears as an
apparent triplet (J HP ) J HH ) 13 Hz) at 19.26 ppm by
1H NMR, while the R-carbon appears as a doublet (J CP
) 14 Hz) at 324.65 ppm by 13C NMR spectroscopy.
Both complexes 4 and 6 react rapidly and quantita-
tively with an excess of HCl to liberate HO2CCHPh2 and
generate the appropriate complex Tp(PR3)(Cl)RudCHR1
[R ) Cy; R1 ) CHdC(CH3)2 (5) or R ) Ph; R1 ) Ph (7)]
(Scheme 3). Complex 7 is analogous to the previously
reported species Tp(PCy3)(Cl)RudCHPh; however, it
was not available by the same synthetic methodology.6
This compound is a light green solid that can be
separated from the free acid by several washes with
toluene at -10 °C. NMR spectroscopy shows the R-pro-
ton of the carbene as a doublet (J HP ) 12 Hz) at 19.40
F igu r e 4. Labeled view of complex 8 with 50% probability
ellipsoids (phenyl groups on phosphine ligand omitted for
clarity).
ppm, while the R-carbon appears as a doublet (J CP
)
19 Hz) at 340.57 ppm.28 Interestingly, Werner has
reported that the metallacycles Cp(PPh3)Ru[κ2-(C,O)-
C(Ar)2OC(CMe)dO] react in a similar fashion with the
chloride sources, such as Et3NHCl and Al2O3/Cl- (al-
though HCl was not reported), to generate the corre-
sponding alkylidenes Cp(PPh3)(Cl)RudCAr2.16
bon of this complex appears at a comparable chemical
shift (201.2 ppm) by 13C NMR spectroscopy.
On the basis of the above evidence, we believe that
the formation of 8 by paths a and b (Scheme 4) proceeds
through the unstable vinylidene complex 8a . This
proposed intermediate cannot be observed by NMR or
IR spectroscopy but undergoes rapid nucleophilic attack
to produce the metallacycle 8. The propensity of vi-
nylidenes to undergo attack by intramolecular nucleo-
philes has been well documented in the literature. A
variety of groups have recently observed similar met-
allacycle formation with ligand nucleophiles including
alcohols,4b amides,4c and pyrazole7a in Tp[Ru] vinylidene
systems. Intramolecular nucleophilic attack on a vi-
nylidene by an adjacent carboxylate oxygen has also
been reported in a Cp[Ru] system.25 However, it is
interesting to note that the O-O chelate complex Tp-
(acac)RudCdCHPh4a is completely stable to this type
of intramolecular attack. This is presumably because
reaction of an acac oxygen with the vinylidene ligand
would result in an unstable, coordinatively unsaturated
species.
Rea ction of 1 w ith P h en yla cetylen e. Complex 1
reacts rapidly with an excess of phenylacetylene to
produce the metallacycle Tp(PPh3)Ru[κ2-(C,O)-C(d
CHPh)OC(CHPh2)dO], 8, in 53% isolated yield (Scheme
4). The identity of complex 8 as the five-membered
chelate as opposed to the tautomeric vinylidene struc-
1
ture (8a ) can be confirmed by NMR spectroscopy. H
NMR shows nine separate resonances for the pyrazolyl
protons, and the proton attached to the â-carbon ap-
pears as a singlet at 5.16 ppm. 13C NMR shows the
R-carbon as a doublet at 210.44 ppm (J HP ) 13 Hz),
significantly upfield of a typical vinylidene 13C chemical
shift.20 Complex 8 is spectroscopically similar to 2, as
well as to the previously reported metallacycles Cp-
(PPh3)Ru[κ2-(C,O)-C(dCHCO2Me)OC(Me)dO]25 (CR
)
227.9 ppm) and (CO)[η1-OdC(Me2)](PiPr3)2Ru[κ2-(C,O)-
29
C(dCHPh)OC(Me)dO]BF4 (CR ) 204.7 ppm), which
As further confirmation of its connectivity, the solid-
state structure of complex 8 was obtained. Suitable
crystals were grown by vapor diffusion of pentane into
a concentrated CH2Cl2 solution of 8 at room tempera-
ture. The collection and refinement data are sum-
marized in Table 1, and a labeled view of 8 is shown in
Figure 4. Notably, this complex crystallizes with two
similar but independent molecules in the asymmetric
unit, and the bond lengths and angles for molecule A
are reported in Table 4. The average Ru-C(1) distance
of 1.992 Å is comparable to that in complex 2 (d(Ru-C)
) 1.997 Å) as well as to that in the related metallacycles
Cp(PPh3)Ru[κ2-(C,O)-C(dCHCO2Me)OC(Me)dO]25 (d-
(Ru-C) ) 2.002(2) Å) and (CO)(η1-OC(Me2)(PiPr3)2Ru-
[κ2-(C,O)-C(dCHPh)OC(Me)dO]BF429 (d(Ru-C) ) 1.967-
(8) Å). As described earlier for complex 2, this short
Ru-C distance points to a contribution from the zwit-
terionic resonance form 8b to the solid-state structure
of 8.30 Additionally, the relatively long average C-O
distance of 1.495 Å and the distorted average Ru-C(1)-
are the products of attack of coordinated carboxylates
on vinylidene or alkynyl ligands.
In an attempt to generate the η1-carboxylate, vi-
nylidene complex Tp(PPh3)(η1-O2CCHPh2)RudCdCHPh
(8a ) Tp(PPh3)(Cl)RudCdCHPh8d was reacted with 1.2
equiv of AgO2CCHPh2 (Scheme 4). The reaction mixture
instantaneously changed color from light red to yellow
with the precipitation of AgCl. However 1H, 31P, and
13C NMR analysis indicated the quantitative formation
of chelate 8, rather than vinylidene 8a . Notably, Hill
and co-workers have reported a similar reaction be-
tween Tp(PPh3)(Cl)RudCdCHAr and [Et2NH2][S2C-
(NMe2)], resulting in coupling of the dithiocarbamate
to the vinylidene moiety to generate the metallacycle
Tp(PPh3)Ru[κ2-(C,S)-C(dCHAr)SC(NEt2)dS].2 The R-car-
(28) The connectivity of complex 7 has been determined by X-ray
crystallography; however, the refined model is of low quality due to a
large region of disordered solvent. Crystal data for 7:
C38.69H36.69-
BCl1.77N6PRu, fw ) 791.33, monoclinic, P21/n (# 14), a ) 10.0980(6) Å,
b ) 30.0953(17) Å, c ) 11.9758(7) Å, â ) 90.225(1)°, V ) 3639.4(4) Å3,
Z ) 4, rcalc ) 1.439 g/cm3, m ) 0.64 mm-1, F000 ) 1609, T ) 98 K.
More information is provided in the Supporting Information.
(29) Esteruelas, M. A.; Lahoz, F. J .; Lopez, A. M.; Onate, E.; Oro,
L. A. Organometallics 1994, 13, 1669.
(30) In solution, the chemical shift of the R-carbon of complex 8 is
more consistent with its formulation as a ruthenium vinyl adduct than
as the tautomeric alkylidene or vinylidene structures [ref 24].

Reaction of Tp(PPh3)Ru(η2-O2CCHPh2)
Organometallics, Vol. 20, No. 25, 2001 5461
(PPh3)Ru[κ2-(C,O)-C(dCHCHPh2)OC(CHPh2)dO] (2) and
Tp(PPh3)Ru[κ2-(C,O)-C(dCHPh)OC(CHPh2)dO] (8), re-
spectively. Complex 1 also reacts cleanly with phenyl-
diazomethane to form the new transition metal ben-
zylidene Tp(PPh3)(η1-O2CCHPh2)RudCHPh (4). Prelimi-
nary results show that the carbene complex 4 is active
as a single-component catalyst for the ring-opening
metathesis polymerization of norbornene. The product
polymer is obtained in low yield and is of low molecular
weight, suggesting that the active catalyst has a rela-
tively short lifetime under the polymerization condi-
tions.
Ta ble 4. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for Com p lex 8 (Molecu le A)
Bond Lengths
Ru-C(1)
Ru-N(1)
Ru-N(3)
Ru-N(5)
Ru-O(1)
1.989(3)
2.191(2)
2.049(2)
2.122(2)
2.1223(19)
Ru-P
2.2918(14)
1.238(3)
1.310(3)
1.491(3)
1.343(4)
O(1)-C(9)
O(2)-C(9)
O(2)-C(1)
C(1)-C(2)
Bond Angles
N(1)-Ru-O(1)
N(3)-Ru-O(1)
Ru-C(1)-O(2)
97.89(8)
171.71(8)
N(5)-Ru-O(1)
89.52(8)
111.60(17)
Ru-O(1)-C(9)
110.64(17) O(2)-C(9)-C(10) 114.6(2)
O(2)-C(1)-C(2) 111.1(2)
O(1)-C(9)-O(2) 123.1(2)
O(1)-C(9)-C(10) 122.4(2)
Ru-C(1)-C(2) 138.1(2)
Exp er im en ta l Section
C(2) and C(2)-C(1)-O(2) angles of 138.1° and 110.7°,
respectively, suggest that the η1-carboxylate, vinylidene
tautomer 8a may also play a role in the solid-state
bonding of this molecule.30
Gen er a l Con sid er a tion s. All manipulations were carried
out using standard Schlenk techniques under an atmosphere
of dry argon. Solid organometallic compounds were transferred
in a nitrogen-filled Vacuum Atmospheres drybox. All NMR
spectra were recorded on a J EOL J NM-GX400 (399.8 MHz 1H;
100.5 MHz 13C; 161.9 MHz 31P). When resolved, the coupling
constants of the tris(pyrazolyl)borate protons were about 2 Hz.
Elemental analyses were performed at the Caltech Analytical
Facility or at Midwest Microlabs (Indianapolis, IN). High-
resolution mass spectral data were obtained from UCLA.
Ma ter ia ls. Toluene, benzene, pentane, and methylene
chloride were dried by passage through solvent purification
columns.32 Deuterated solvents were vacuum transferred from
the appropriate drying agents, degassed by three consecutive
freeze-pump-thaw cycles, and stored in the drybox. Diethyl
diallylmalonate (Aldrich) and phenylacetylene (Aldrich) were
passed through a plug of activated alumina and degassed by
three consecutive freeze-pump-thaw cycles. Norbornene was
sublimed prior to use and was stored in the drybox freezer.
HO2CCHPh2 and KTp were obtained from commercial sources
and used as received. NaO2CCHPh2 was prepared by the
reaction of the free acid with NaOH, and AgO2CCHPh2 was
prepared by the reaction of the sodium salt with AgNO3 in
H2O. (PCy3)2(Cl)2RudCHCHC(CH3)2,15b TpRuCl(PPh3)2,33 Tp-
(PPh3)(Cl)RudCdCHPh,8d diphenylcyclopropene34 and phe-
nyldiazomethane35 were prepared according to literature
procedures.
In vestiga tion of th e Olefin Meta th esis Activities
of Com p lexes 2-8. The activities of complexes 2-8 for
both ring-opening metathesis polymerization (ROMP)
and ring-closing metathesis (RCM) reactions were in-
vestigated. Compounds 2-8 do not to react with diethyl
diallylmalonate or other common RCM substrates even
after several days at elevated temperatures.31 Com-
plexes 2 and 8 also fail to react with norbornene and
merely decompose in the presence of this substrate after
2 days at 45 °C. This lack of olefin metathesis activity
is consistent with the formulation of 2 and 8 as metal-
lacycles rather than the tautomeric vinylidene species.
After a week at 45 °C, 5, 6, and 7 also fail to polymerize
norbornene. Notably, the recently reported Tp[Ru] ben-
zylidenes Tp(PCy3)(X)RudCHPh [X ) Cl, pyridine, CH3-
CN, H2O] are similarly unreactive toward norbornene
and strained cyclic olefins.6
In contrast, complex 4 exhibits low activity as a
single-component catalyst for the ROMP of norbornene.
After 24 h at 45 °C, 1H NMR shows approximately
5-15% of ROMP product relative to the norbornene
starting material. No propagating species can be ob-
served during this polymerization (presumably due to
poor initiation), and the catalyst decomposes completely
after 24 h of reaction. Attempts to precipitate the
resulting poly(norbornene)s into methanol were unsuc-
cessful, suggesting that the products are low molecular
weight and oligomeric in nature.
Tp (P P h 3)Ru (η2-O2CCHP h 2) (1). TpRu(PPh3)2Cl (2.4 g, 2.7
mmol) and NaO2CCHPh2 (0.77 g, 3.3 mmol) were combined
in THF (50 mL), and the resulting suspension was refluxed
for 24 h. The THF was removed under vacuum, and the solids
were washed with pentane (4 × 25 mL). The resulting yellow
product was dissolved in a 3:1 mixture of CH2Cl2 to pentane,
filtered through a plug of Celite, and concentrated to dryness
to give 1.75 g (82% yield) of a yellow powder. Analytically pure
samples were obtained by recrystallization from CH2Cl2/
pentane. 31P{1H} NMR (CD2Cl2): δ 63.7 (s). 1H NMR (CD2-
Cl2): δ 7.83 (s, 1H, Tp), 7.65 (s, 2H, Tp), 7.35-7.11 (multiple
peaks, 26H, PPh3, CHPh2, Tp), 6.84 (s, 2H, Tp), 6.19 (s, 1H,
Tp), 5.75 (s, 2H, Tp), 4.56 (s, 1H, CHPh2). 13C{1H} NMR (CD2-
Cl2): δ 186.97 (CdO), 147.90, 139.56, 139.03, 136.34, 135.11,
128.93, 128.36, 126.72, 105.82, 105.22, 60.62. IR (C6H6): 2468
cm-1 (B-H), 1526 cm-1 (OCO). Anal. Calcd for C41H36N6BO2-
PRu: C, 62.52; H, 4.61; N, 10.67. Found: C, 62.79; H, 4.70;
N, 11.00.
Notably, complexes 4 and 7 exhibit significantly lower
activity for the ROMP of norbornene than the previously
reported vinylidene adduct, Tp(PPh3)(Cl)RudCdCH-
Ph.8d,10 The dramatic differences in reactivity between
these apparently similar compounds are currently under
investigation in our laboratory.
Su m m a r y
A new complex, Tp(PPh3)Ru(η2-O2CCHPh2) (1), has
been prepared and has proven a versatile precursor for
the preparation of new Tp[Ru] organometallics. Com-
plex 1 reacts with 3,3-diphenylcyclopropene and phe-
nylacetylene to generate the metallacyclic species Tp-
Tp(P P h 3)Ru [K2-(C,O)-C(dCHCHP h 2)OC(CHP h 2)dO] (2).
Complex 1 (300 mg, 0.38 mmol) and diphenylcyclopropene (300
(32) Pangborn, A. B.; Giardello, M. A.; Grubbs, R. H.; Rosen, R. K.;
Timmers, F. J . Organometallics 1996, 15, 1518.
(33) Alcock, N. W.; Burns, I. D.; Claire, K. S.; Hill A. F. Inorg. Chem.
1992, 31, 2906.
(34) Nguyen, S. T., Ph.D. Thesis, California Institute of Technology,
1995.
(31) RCM is generally a more challenging reaction than ROMP for
olefin metathesis catalysts. For example (PPh3)2Cl2RudCHPh is an
active catalyst for the ROMP of norbornene and cyclobutene, but is
completely unreactive toward RCM substrates such as diethyl dial-
lylmalonate. Dias, E. L.; Nguyen, S. T.; Grubbs, R. H. 1996, unpub-
lished results.
(35) (a) Closs, G. L.; Moss, R. A. J . Am. Chem. Soc. 1964, 86, 4042.
(b) Yates, P.; Shapiro, B. L. J . Org. Chem. 1958, 23, 759.

5462 Organometallics, Vol. 20, No. 25, 2001
Sanford et al.
mg, 1.56 mmol) were dissolved in toluene (20 mL). The
resulting solution was stirred for 18 h, during which time it
changed color from yellow to light orange. The reaction mixture
was evaporated to dryness, and the solids were washed with
cold (-10 °C) pentane (3 × 15 mL). The resulting yellow-orange
solid was dried in vacuo to give 180 mg (48%) of product.
Analytically pure samples were obtained by recrystallization
Tp (P Cy3)(η1-O2CCHP h 2)Ru dCHCHdC(CH3)2 (6). Com-
plex 5 (200 mg, 0.29 mmol) and AgO2CCHPh2 (110 mg, 0.32
mmol) were combined in CH2Cl2 (15 mL). The reaction was
stirred for 3 h and then filtered through a plug of Celite. The
solvent was removed under vacuum to afford 150 mg (61%) of
1
a dark green product. 31P{1H} NMR (CD2Cl2): δ 39.19 (s). H
NMR (CD2Cl2): δ 19.26 (t, 1H, J HP ) J HH ) 13 Hz, RudCHCH),
7.97 (s, 1H, Tp), 7.87 (s, 1H, Tp), 7.77 (s, 1H, Tp), 7.55 (s, 1H,
Tp), 7.37-7.25 (multiple peaks, 3H, PPh3, Tp), 7.04-6.72
(multiple peaks, 14H, PPh3, RudCHCH), 6.52 (s, 1H, Tp), 6.29
(s, 1H, Tp), 6.05 (s, 1H, Tp), 5.84 (s, 1H, Tp), 4.74 (s, 1H,
CHPh2), 1.84-0.82 (multiple peaks, 33H, PCy3), 1.75 (s, 3H,
CMe), 1.30 (s, 3H, CMe). 13C{1H} NMR (CD2Cl2): δ 324.65 (d,
RudCHPh, J CP ) 14 Hz ), 177.21 (CdO), 145.82, 145.19,
144.85, 144.77, 143.62, 143.02, 140.09, 136.65, 134.65, 133.28,
129.00, 128.96, 127.69, 127.51, 125.44, 125.13, 105.78, 105.29,
104.24, 61.62, 34.12, 33.94, 28.76, 27.97, 27.87, 27.75, 26.48,
20.69. IR (CD2Cl2): 2475 cm-1 (B-H), 1617 cm-1 (OCO). Anal.
1
from toluene/pentane. 31P{1H} NMR (CD2Cl2): δ 61.3 (s). H
NMR (CD2Cl2): δ 7.71 (s, 1H, Tp), 7.67 (s, 1H, Tp), 7.56 (s,
1H, Tp), 7.3-6.75 (multiple peaks, 36 H, CPh2, PPh3, CHPh2,
Tp), 6.45 (s, 1H, Tp), 6.41 (s, 1H, Tp), 5.90 (s, 1H, Tp), 5.84 (s,
1H, Tp), 5.78 (s, 1H, Tp), 5.42 (d, 1H, J HH ) 9 Hz, Ru-Cd
CHCH(Ph)2), 4.86 (s, 1H, CHPh2), 4.81 (d, 1H, J HH ) 9 Hz,
CHCH(Ph)2). 13C{1H} NMR (CD2Cl2): δ 203.97 (d, Ru-C, J CP
) 17 Hz ), 180.43 (CdO), 147.15, 146.57, 146.12, 144.05,
140.73, 138.09, 137.89, 135.74, 135.01, 134.65, 134.55, 134.01,
133.91, 129.55-127.76 (multiple peaks), 127.03, 125.47, 125.30,
118.97, 105.45, 104.93, 104.42, 56.47, 47.76. IR (CD2Cl2): 2477
cm-1 (B-H), 1618 cm-1 (OCO). Anal. Calcd for C56H48N6BO2-
PRu: C, 68.64; H, 4.94; N, 8.58. Found: C, 68.43; H, 4.58; N,
8.84.
Calcd for
C46H62N6BO2PRu: C, 63.22; H, 7.15; N, 9.62.
Found: C, 63.33; H, 7.00; N, 9.29.
Tp (P P h 3)(Cl)Ru dCHP h (7). To a solution of 6 (190 mg,
0.22 mmol) in CH2Cl2 (20 mL) was added HCl (1 mL of a 1.0
M solution in diethyl ether, 1.0 mmol). An immediate color
change from dark to light green was observed, and the reaction
was stirred for 30 min. The solvents were removed under
vacuum, and the resulting green residue was washed with -10
°C toluene (3 × 10 mL) and then with a 3:1 mixture of pentane/
toluene (2 × 15 mL). The solids were redissolved in CH2Cl2
(15 mL), filtered through a plug of Celite, and concentrated
under vacuum to afford 49 mg (33%) of the light green product.
Satisfactory elemental analyses could not be obtained; however
the structure of this complex was confirmed by X-ray crystal-
lography (see Supporting Information) and by mass spectrom-
etry. 31P{1H} NMR (CD2Cl2): δ 39.74 (s). 1H NMR (CD2Cl2):
δ 19.40 (d, 1H, J HP ) 12 Hz, RudCHPh), 7.93 (s, 1H, Tp), 7.78
(s, 1H, Tp), 7.73 (s, 1H, Tp), 7.56 (s, 1H, Tp), 7.40-6.95
(multiple peaks, 19H, PPh3, RudCHPh), 6.50 (s, 1H, Tp), 6.13
(s, 1H, Tp), 5.92 (s, 1H, Tp), 5.56 (s, 2H, Tp). 13C{1H} NMR
(CD2Cl2): δ 340.57 (d, RudCHPh, J CP ) 19 Hz ), 135.95,
134.67, 134.28, 134.11, 132.37, 132.16, 131.95, 131.79, 129.84,
128.73, 127.88, 127.72, 106.06, 105.60, 105.35. IR (CD2Cl2):
2480 cm-1 (B-H). Anal. Calcd for C34H31N6BClPRu: C, 58.17;
H, 4.45; N, 11.97. Found: C, 59.46; H, 4.69; N, 11.18. FAB-
HRMS: m/z calcd for M+ 702.1173; m/z found 702.1184.
Tp (P P h 3)Ru [K2-(C,O)-C(dCHP h )OC(CHP h 2)dO] (8). (a)
To a solution of 1 (150 mg, 0.19 mmol) in CH2Cl2 (10 mL) was
added phenylacetylene (84 µL, 0.76 mmol). The reaction was
stirred for 30 min, during which time a color change from
orange to light yellow was observed, and the volatiles were
removed under vacuum. The resulting solids were washed with
3 × 15 mL of pentane, then dissolved in 10 mL of C6H6 and
filtered through a plug of Celite. The light yellow solution was
concentrated in vacuo to give 90 mg (53%) of product. Analyti-
cally pure samples were obtained by recrystallization from
CH2Cl2/pentane. (b) TpRudCdCHPh(PPh3)(Cl) (15 mg, 0.021
mmol) and AgO2CCHPh2 (8 mg, 0.025 mmol) were combined
in an NMR tube. CD2Cl2 was added, and the reaction was
shaken for 5 min. 31P{1H} NMR (CD2Cl2): δ 62.12 (s). 1H NMR
(CD2Cl2): δ 7.76 (s, 1H, Tp), 7.71 (s, 1H, Tp), 7.61 (s, 1H, Tp),
7.31-6.76 (multiple peaks, 32H, CHPh, PPh3, CHPh2, Tp), 6.49
(s, 1H, Tp), 5.99 (s, 1H, Tp), 5.95 (s, 1H, Tp), 5.85 (s, 1H, Tp),
5.16 (s, 1H, Ru-CdCHPh), 4.93 (s, 1H, CHPh2). 13C{1H} NMR
(CD2Cl2): δ 210.44 (d, Ru-CdCHPh, J CP ) 13 Hz ), 181.40
(CdO), 145.93, 144.27, 140.26, 137.74, 137.54, 137.47, 136.03,
134.76, 134.39, 134.21, 134.12, 133.91, 129.35, 129.11, 128.87,
127.75, 127.70, 127.60, 127.26, 123.15, 117.03, 105.60, 105.12.
IR (CD2Cl2): 2479 cm-1 (B-H), 1612 cm-1 (OCO). Anal. Calcd
for C49H42N6BO2PRu: C, 66.14; H, 4.76; N, 9.45. Found: C,
66.21; H, 4.18; N, 9.18.
Obser va tion of Tp (P P h 3)(η1-O2CCHP h 2)Ru dCHCHdC-
(P h )2 (3). Complex 1 (30 mg, 0.038 mmol) and diphenylcyclo-
propene (30 mg, 0.16 mmol) were combined in an NMR tube
in the drybox. CD2Cl2 (0.75 mL) was added, and the reaction
was shaken for 24 h at room temperature. 1H NMR after 24 h
showed a trace of the alkylidene product as an apparent triplet
at 18.56 ppm.
Tp (P P h 3)(η1-O2CCHP h 2)Ru dCHP h (4). To a solution of
1 (500 mg, 0.635 mmol) in CH2Cl2 (25 mL) was added
phenyldiazomethane (150 mg, 1.27 mmol). The resulting
solution was stirred for 3 h at room temperature, during which
time it changed color from yellow to red to brown-green, and
finally to dark green. The volatiles were removed in vacuo,
and the solids were washed with 3 × 20 mL of pentane and
dried under vacuum to leave 435 mg (78%) of a dark green
powder. 31P{1H} NMR (CD2Cl2): δ 44.8 (s). 1H NMR (CD2Cl2):
δ 19.01 (d, 1H, J HP ) 15 Hz, RudCHPh), 7.92 (s, 1H, Tp), 7.78
(s, 1H, Tp), 7.67 (s, 1H, Tp), 7.62-7.03 (multiple peaks, 31H,
PPh3, CHPh2, CHPh, and Tp), 6.61 (s, 1H, Tp), 6.11 (s, 1H,
Tp), 5.73 (s, 1H, Tp), 5.61 (s, 1H,Tp), 5.58 (s, 1H, Tp), 4.80 (s,
1H, CHPh2). 13C{1H} NMR (CD2Cl2): δ 339.63 (d, RudCHPh,
J CP ) 11 Hz ), 177.22 (CdO), 149.48, 145.87, 145,16, 144.40,
142.76, 142.52, 136.27, 135.55, 134.21, 134.02, 133.93, 132.50,
132.41, 132.09, 131.14, 129.70, 129.11, 128.84, 128.34, 127.99,
127.90, 127.62, 125.89, 125.53, 105.68, 105.62, 104.96, 60.90.
IR (CD2Cl2): 2480 cm-1 (B-H), 1614 cm-1 (OCO). Anal. Calcd
for C48H42N6BO2PRu: C, 65.68; H, 4.82; N, 9.57. Found: C,
65.87; H, 4.80; N, 9.54.
Tp (P Cy3)(Cl)R u dCH CH dC(CH 3)2 (5). (PCy3)2Cl2Rud
CHCHdC(CH3)2 (1.0 g, 0.13 mmol) and KTp (0.32 g. 0.13
mmol) were dissolved in CH2Cl2 (20 mL), and the reaction was
stirred for 5 h, over which time a color change from purple to
light green was observed. Pentane (50 mL) was added, and
the reaction was filtered through a plug of Celite. The resulting
solution was concentrated to 5 mL, and pentane (70 mL) was
added to precipitate the bright green product. The solids were
collected on a frit, washed with pentane (4 × 20 mL), and dried
under vacuum to provide 0.63 g (72%) of product. 31P{1H} NMR
(CD2Cl2): δ 35.02 (s). 1H NMR (CD2Cl2): δ 19.53 (d of d’s, 1H,
J HP ) 9 Hz, J HH ) 13 Hz, RudCHCH), 8.42 (s, 1H, Tp), 7.84
(s, 1H, Tp), 7.77 (s, 1H, Tp), 7.53 (s, 1H, Tp), 7.24 (d, 1H, J HH
) 13 Hz, RudCHCH), 6.74 (s, 1H, Tp), 6.71 (s, 1H, Tp), 6.39
(s, 1H, Tp), 6.12 (s, 1H, Tp), 5.95 (s, 1H, Tp), 1.88-0.96
(multiple peaks, 33H, PCy3), 1.64 (s, 3H, CMe), 1.21 (s, 3H,
CMe). 13C{1H} NMR (CD2Cl2): δ 332.62 (d, RudCHPh, J CP
)
14 Hz), 147.86, 145.68, 144.79, 142.57, 139.59, 136.57, 135.40,
133.68, 105.96, 105.78, 104.71, 34.56, 34.38, 29.16, 28.51,
28.10, 28.01, 27.99, 28.92, 27.57, 26.46, 21.00. IR (CD2Cl2):
2478 cm-1 (B-H). Anal. Calcd for C32H51N6BClPRu: C, 55.06;
H, 7.36; N, 12.04. Found: C, 54.91; H, 7.22; N, 12.08.
P olym er iza tion of Nor bor n en e w ith Com p lex 4. Com-
plex 4 (5.0 mg, 0.0057 mmol) and norbornene (30 mg, 0.31

Reaction of Tp(PPh3)Ru(η2-O2CCHPh2)
Organometallics, Vol. 20, No. 25, 2001 5463
mmol, 53 equiv) were combined in an NMR tube. CD2Cl2 (1
mL) was added, and the reaction mixture was shaken for 1
min. The reaction was allowed to stand at room temperature
for 2 h and was then heated to 45 °C and monitored every 12
h by 1H NMR spectroscopy. After 24 h, the carbene resonance
had completely disappeared, and traces (approximately 5-10%)
of polynorbornene (approximately 1:1 cis/trans) were observed
by H NMR. The reaction mixture was poured into methanol;
however no polymer precipitated, suggesting that a very low
molecular weight product is formed.
the Ueq of the attached carbon atom; all other hydrogen atoms
were refined isotropically.
Direct methods were used in the structure solution of 2.
There are three molecules (A, B, and C) in the asymmetric
unit, with slightly different orientations of some of the phenyl
groups. Molecules B and C are most similar. Also present are
one molecule of n-pentane and a toluene molecule disordered
on a center of symmetry. This was not the typical toluene on
a center, but a much less tractable example requiring a total
of 12 restraints to keep it geometrically reasonable: nearest
neighbor (1.39(0.001), 1.54(0.001)), next-nearest neighbor
(2.55(0.01), flat (0.001); all carbon atoms were given equal
anisotropic displacement parameters. The largest excursions
in the final difference map were near this molecule (1.54 e
Å-3 at 0.70 Å from H(7E) and -1.6 e Å-3 at 0.34 Å from H(5)).
All non-hydrogen atoms were refined anisotropically. The
hydrogen atoms for both solvent molecules were placed at
calculated positions; the coordinates of the other hydrogen
atoms were refined with a Uiso 1.2 times the Ueq of the attached
atom.
The structure of 8 was also determined via direct methods
and subsequent difference maps. The two molecules in the
asymmetric unit have essentially the same conformation, as
does the single independent molecule in the toluene solvate.39
Also present is one somewhat-disordered molecule of dichlo-
romethane with large Ueq’s. The largest excursions in the final
difference map are near this molecule (1.52 e Å-3 at 1.02 Å
from Cl(1) and -1.23 e Å-3 at 0.43 Å from Cl(1), -1.19 e Å-3
at 0.70 Å from Cl(2), and -1.05 e Å-3 at 0.57 Å from Cl(1)).
The hydrogen atoms of the dichloromethane were placed at
calculated positions; the coordinates of the other hydrogen
atoms were refined with a Uiso 1.2 times the Ueq of the attached
atom. All non-hydrogen atoms were refined anisotropically.
1
Cr ysta l Str u ctu r es of 1, 2, a n d 8. Gen er a l. Crystal,
intensity collection, and refinement details are summarized
in Table 1 for complexes 1, 2, and 8.28,36
Da ta Collection a n d P r ocessin g. All data were collected
at low temperature with ω-scans on a Nonius CAD-4 serial
diffractometer equipped with
a Crystal Logic CL24 low-
temperature device using graphite-monochromated Mo KR
radiation with λ ) 0.71073 Å. The crystals were mounted on
glass fibers with Paratone-N oil. The unit cell was calculated
from 25 centered reflections. Two sets of data were collected
with ω-scans. CRYM37 programs were used to apply Lorentz
and polarization factors and to merge the multiples in the
appropriate point group, 2/ m for 1 and P1h for 2 and 8. No
absorption corrections were applied for any complex. For 2 and
8, the individual backgrounds were replaced by a background
function of 2θ derived from weak reflections. Small decay
corrections (0.33% for 1, 0.51% for 2, and 0.40% for 8) were
based on three check reflections measured every 75 min.
Weights w were calculated as 1/σ2(Fo2); variances (σ2(Fo2)) were
derived from counting statistics plus an additional term,
(0.014I)2; variances of the merged data were obtained by
propagation of error plus another additional term, (0.014 I )2.
St r u ct u r e An a lysis a n d R efin em en t . SHELX9738 was
used to solve and to refine (using full-matrix least-squares)
all structures. The structure of 1 was determined by the
Patterson method and successive structure factor-Fourier
calculations. The asymmetric unit consists of one molecule of
1 and one dichloromethane. The CH2Cl2 is disordered over two
sites (0.500(1):0.500(1)) as is one of the phenyl groups (C(3)-
C(8)) of the carboxylate (0.505(6):0.495(6)). All non-hydrogen
atoms were refined anisotropically. Hydrogen atoms bonded
to disordered carbons (C(3)-C(8), C(3A)-C(8A), C(50), and
C(60)) were placed in idealized positions with Uiso 1.2 times
Ack n ow led gm en t . Lawrence M. Henling and
Michael W. Day are gratefully acknowledged for carry-
ing out the X-ray crystallographic studies described
herein. The authors also would like to thank Bill Ward
and Arnab Chatterjee for critical reading of the manu-
script. M.R.V. acknowledges the Caltech SURF program
for a summer fellowship. This work was supported by
the National Science Foundation.
Su p p or tin g In for m a tion Ava ila ble: Tables of crystal
and intensity collection data, positional and displacement
parameters, complete bond distances and bond angles, and
figures showing the complete atom-labeling schemes for
complexes 1, 2, 7, and 8. This material is available free of
charge via the Internet at http://pubs.acs.org.
(36) The Crystallographic Information Files (CIF) have been depos-
ited with the Cambridge Crystallographic Data Centre as supplemen-
tary publications for complexes 1 (CCDC 133555), 2 (CCDC 164301),
7 (CCDC 165163), 8‚C7H8 (CCDC 133554), and 8‚(CH2Cl2) (CCDC
164302). Copies of the data can be obtained, free of charge, on
application to CCDC, 12 Union Road, Cambridge CB2 1EZ, UK (fax:
+44 1223 336033 or e-mail: deposit@ccdc.cam.ac.uk). Structure factors
are available from the authors via e-mail: xray@caltech.edu.
(37) Duchamp, D. J . American Crystallographic Association Meet-
ing, Bozeman, MT, Paper B14, 1964; pp 29-30.
OM010558V
(39) Crystal data for 8‚C7H8: C56H50BN6O2PRu, fw ) 981.91,
monoclinic, P21/n (# 14), a ) 13.7367(7) Å, b ) 19.5683(10) Å, c )
18.5679(10) Å, â ) 102.091(1)°, V ) 4880.4(4) Å3, Z ) 4, rcalc ) 1.336
g/cm3, m ) 0.40 mm-1, F000 ) 2032, T ) 293 K. More information is
provided in the Supporting Information.
(38) Sheldrick, G. M. SHELX97: Program for Structure Refinement;
Universta¨t Go¨ttingen: Germany, 1997.