A four-electron πT-alkyne complex as precursor for allenylidene derivatives: Preparation, structure, and reactivity of [Os(η5- C5H5)(C=C=CPh2)L(PiPr 3)]PF6 (L = CO, PHPh2)

Article abstract of DOI:10.1021/om049479k

The properties of the πalkyn complex [Os(η⁵-C ₅H₅){η²HC ≡ CC(OH)PH ₂}(PⁱPr₃)]PF₆ were investigated. It was found that the alkyne acted as a four electron donor, and was a useful starting material to prepare allenylidene derivatives. It was shown that the reactions of the complex with carbon monoxide and diphenylphosphine lead to the mixed ligand allenylidene compounds. The allenylidene ligand of both complexes was also found to be as a result of the dehydration of hydroxyvinylidene intermediates.

Full text of DOI:10.1021/om049479k

Organometallics 2004, 23, 5787-5798
5787
A Four-Electron π-Alkyne Complex as Precursor for
Allenylidene Derivatives: Preparation, Structure, and
Reactivity of [Os(η5-C5H5)(CdCdCPh2)L(PiPr3)]PF6
(L ) CO, PHPh2)
Adriana Asensio, Mar´ıa L. Buil,* Miguel A. Esteruelas,* and Enrique On˜ate
Departamento de Quı´mica Inorga´nica, Instituto de Ciencia de Materiales de Arago´n,
Universidad de Zaragoza-CSIC, 50009 Zaragoza, Spain
Received July 13, 2004
The π-alkyne complex [Os(η5-C5H5){η2-HCtCC(OH)Ph2}(PiPr3)]PF6 (1), where the alkyne
acts as a four-electron donor ligand, reacts with CO to give initially the two-electron π-alkyne
derivative [Os(η5-C5H5){η2-HCtCC(OH)Ph2}(CO)(PiPr3)]PF6 (2). In dichloromethane, complex
2 isomerizes into the hydroxyvinylidene [Os(η5-C5H5){dCdCHC(OH)Ph2}(CO)(PiPr3)]PF6 (3),
which dehydrates to afford the allenylidene [Os(η5-C5H5)(dCdCdCPh2)(CO)(PiPr3)]PF6 (4).
Complex 1 also reacts with PHPh2. In this case, the reaction initially gives the hydride-
hydroxyalkynyl intermediate [OsH(η5-C5H5){CtCC(OH)Ph2}(PHPh2)(PiPr3)]PF6 (5). Similar
to 2, in dichloromethane, complex 5 isomerizes into the hydroxyvinylidene [Os(η5-C5H5){d
CdCHC(OH)Ph2}(PHPh2)(PiPr3)]PF6 (6), which dehydrates to afford [Os(η5-C5H5)(dCdCd
CPh2)(PHPh2)(PiPr3)]PF6 (7). In the presence of HPF6, complex 4 isomerizes into [Os(η5-
C5H5)(3-phenyl-1-indenylidene)(CO)(PiPr3)]PF6 (8). Under the same conditions, compound
7 affords the dicationic alkenylcarbyne derivative [Os(η5-C5H5)(tC-CHdCPh2)(PHPh2)(Pi-
Pr3)](PF6)2 (9). The allenylidene ligand of 4 undergoes the addition of carbodiimides to give
iminiumazetidinylidenemethyl derivatives. The reaction with N,N′-dicyclohexylcarbodiimide
affords [Os(η5-C5H5){CHdCC(Ph)2N(Cy)+C+NdC(CH2)4CH2}(CO)(PiPr3)]PF6 (10), whereas
the reaction with N,N′-diisopropylcarbodiimide leads to [Os(η5-C5H5){CHdCC(Ph)2N-
(iPr)+C+NdC(CH3)2}(CO)(PiPr3)]PF6 (11). Complex 4 also reacts with methanol and aniline.
The addition of methanol to the allenylidene 4 gives [Os(η5-C5H5){C(OCH3)CHdCPh2}(CO)-
(PiPr3)]PF6 (12), which undergoes deprotonation at the CHdCPh2 group to afford Os(η5-
C5H5){C(OCH3)dCdCPh2}(CO)(PiPr3) (13). The addition of aniline leads to [Os(η5-C5H5)-
{C(CHdCPh2)dNHPh}(CO)(PiPr3)]PF6 (14). Treatment of 14 with NaOCH3 gives Os(η5-
C5H5){C(CHdCPh2)dNPh}(CO)(PiPr3) (15). Complexes 4, 7, and 8 have been characterized
by X-ray diffraction analysis.
Introduction
steric properties of the auxiliary ligands on the metal.1b
The coordination of the π-acidic carbonyl group en-
hances the reactivity associated with the allenylidene
spine, favoring the addition of neutral RXH nucleophiles
to the CR-Câ double bond.2 However, phosphines inhibit
the addition of the latter and direct charged nucleophiles
toward the Cγ atom.3
Allenylidene complexes of the iron triad, in particular
cationic half-sandwich ruthenium derivatives, have
attracted a great deal of attention in recent years, as a
new type of organometallic intermediate that may have
unusual reactivity in stoichiometric and catalytic pro-
cesses.1
The reactivity of cationic half-sandwich ruthenium
allenylidene compounds is mainly governed by the
electron-deficient character of the CR and Cγ atoms of
the cumulene chain. The type of nucleophilic addition
and its regioselectivity is controlled by the electronic and
The chemistry of the half-sandwich osmium allen-
ylidene complexes is a field much less known than the
chemistry of the ruthenium counterparts. Osmium
allenylidene complexes are very scarce,3b,4 and the
cationic half-sandwich derivatives are still more rare.
Reported compounds of this type include [Os(η5-C9H7)-
(dCdCdCR2)(PPh3)2]PF6 (R ) Ph2, C12H8),3b [Os(η5-
* To whom correspondence should be addressed. E-mail: maester@
posta.unizar.es.
(1) (a) Bruce, M. I. Chem. Rev. 1998, 98, 2797. (b) Cadierno, V.;
Gamasa, M. P.; Gimeno, J. Eur. J. Inorg. Chem. 2001, 571. (c)
Guerchais, V. Eur. J. Inorg. Chem. 2002, 783. (d) Castarlenas, R.;
Dixneuf, P. H. Angew. Chem., Int. Ed. 2003, 42, 4524. (e) Cadierno,
V.; Gamasa, M. P.; Gimeno, J.; Pe´rez-Carren˜o, E.; Garc´ıa-Granda, S.
J. Organomet. Chem. 2003, 670, 75. (f) Castarlenas, R.; Fischmeister,
C.; Bruneau, C.; Dixneuf, P. H. J. Mol. Catal. A: Chem. 2004, 213,
31.
C5H5)(dCdCdCPh2)(PR3)2]PF6 (R ) iPr,4d Ph4g), [Os{η5-
C5H4(CH2)2PPh2}(dCdCdCPh2)(PiPr3)]PF6,4h [Os(η5-
C5 H5 ){dCdCdCHCtC-Os(η5 -C5 H5 )(PPh3 )2 }-
(PPh3)2]+,4f and [Os(η6-arene)(dCdCdCR2)XL]PF6.4e
10.1021/om049479k CCC: $27.50 © 2004 American Chemical Society
Publication on Web 10/20/2004

5788 Organometallics, Vol. 23, No. 24, 2004
Asensio et al.
The limited development of the osmium chemistry in
the allenylidenes area is a consequence of the method
generally employed to the preparation of cumulene
complexes of the iron triad. The procedure widely used
in the synthesis of cationic half-sandwich ruthenium-
and osmium-allenylidene derivatives involves the treat-
ment of chloro-phosphine or chloro-carbonyl-phosphine
starting materials with terminal alkynols in the pres-
ence of NH4PF6, NaBPh4, or related salts.3b,4d-h,5 In this
context, it should be noted that, in general, the Os(η5-
C5H5)L3 species are more inert than their ruthenium
analogues and that the basicity of osmium is higher
than the basicity of ruthenium. The great inertness of
the Os(η5-C5H5)L3 complexes hinders the extraction of
the chlorine ligand. As a consequence of the high
basicity of the metallic center, for the osmium systems,
the metalations of the substituents of the phosphines4h,7
are reactions that can compete with the activation of
the alkynol.
Four-electron-alkyne complexes are species where
alkyne
donation supplements classic metal-olefin
bonding.8 Although the chemistry of these compounds
has been centered at early transition metals, mainly
molybdenum and tungsten,9 we have recently reported
that the π-alkyne complexes Os(η5-C5H5)Cl(η2-HCtCR)-
(PiPr3) (R ) C(OH)Ph2, C(OH)Me) can be easily con-
verted into stable [Os(η5-C5H5)(η2-HCtCR)(PiPr3)]+ de-
rivatives, containing a four-electron-donating alkyne.10
We have now observed that the four-electron-alkyne
complex [Os(η5-C5H5)(η2-HCtCC(OH)Ph2)(PiPr3)]PF6 is
an easy entry to cationic half-sandwich osmium alle-
nylidene compounds. It affords a general method to
prepare mixed-ligand derivatives of the type [Os(η5-
C5H5)(dCdCdCPh2)L(PiPr3)]+. As a consequence of the
latter, this paper reports a comparative study on the
formation mechanisms of complexes [Os(η5-C5H5)(dCd
CdCPh2)L(PiPr3)]PF6 (L ) CO, PHPh2) and the reactiv-
ity of both compounds.
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Results and Discussion
1. Preparation and Characterization of [Os(η5-
C5H5)(dCdCdCPh2)(CO)(PiPr3)]PF6. The mixed car-
bonyl-phosphine complex [Ru(η5-C5Η5)(dCdCdCPh2)-
(CO)(PiPr3)]BF4 is the most versatile and one of the best
known allenylidenes of ruthenium.2 It is prepared by a
three-step procedure involving the protonation of the
monohydride RuH(η5-C5Η5)(CO)(PiPr3) to give the di-
hydrogen derivative [Ru(η5-C5Η5)(η2-H2)(CO)(PiPr3)]+,
the displacement of the dihydrogen ligand by acetone,
and the subsequent reaction of the resulting acetone
complex with 1,1-diphenyl-2-propyn-1-ol.2a However,
attempts to prepare the osmium counterpart by a
similar procedure starting from the monohydride OsH-
(η5-C5Η5)(CO)(PiPr3) have been unsuccessful. In contrast
to ruthenium, the protonation of the osmium monohy-
dride leads to the osmium(IV) dihydride [OsH2(η5-
C5Η5)(CO)(PiPr3)]+,11 which is stable in acetone and
quenches the allenylidene preparation. In light of this
difficulty, we look for an alternative. An easy and
effective method to prepare the allenylidene osmium
compound is shown in Scheme 1.
Under 1 atm of carbon monoxide, complex [Os(η5-
C5Η5){η2-HCtCC(OH)Ph2}(PiPr3)]PF6 (1) rapidly coor-
dinates a carbon monoxide molecule, to give the carbo-
nyl intermediate [Os(η5-C5Η5){η2-HCtCC(OH)Ph2}-
(CO)(PiPr3)]PF6 (2). At room temperature in dichlo-
romethane-d2 as solvent, the transformation from 1 to
1
2 is quantitative after 1 min, according to the H and
13C{1H} NMR spectra of the resulting solution.
(6) Atwood, J. D. Inorganic and Organometallic Reaction Mecha-
nisms; VCH Publisher: New York, 1997; Chapter 3.
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S.; Templeton, J. L. Coord. Chem. Rev. 2000, 206-207, 199.
(10) Carbo´, J. J.; Crochet, P.; Esteruelas, M. A.; Jean, Y.; Lledo´s,
A.; Lo´pez, A. M.; On˜ate, E. Organometallics 2002, 21, 305.
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Organometallics 1996, 15, 878.

Precursor for Allenylidene Derivatives
Organometallics, Vol. 23, No. 24, 2004 5789
Scheme 1
Figure 1. Molecular diagram for the cation of [Os(η5-
C5Η5){)CdCdCPh2}(CO)(PiPr3)]PF6 (4). Thermal ellip-
soids are shown at 50% probability.
The 1H and 13C{1H} NMR spectra of 2 reflect the
conversion of the π-alkyne ligand, from four-electron
donor to two-electron donor, as a consequence of the
carbon monoxide coordination. In the 1H NMR spec-
trum, the C(sp)-H resonance appears at 5.05 ppm as a
doublet with a H-P coupling constant of 13.2 Hz. This
resonance agrees well with that observed for the com-
plex OsCl(η5-C5Η5){η2-HCtCC(OH)Ph2}(PiPr3) (d, 4.3,
J(HP) ) 9.0 Hz),4a where the alkyne acts as a two-
electron-donor ligand. However, it is shifted 4.4 ppm to
higher field with regard to that of 1 (δ, 9.43). The H-P
coupling constant is also sensitive to the coordination.
Its value is 13.2 Hz smaller in 2 than in 1 (J(PH) )
26.4 Hz). In the 13C{1H} NMR spectrum of 2, the C(sp)
resonances of the alkyne are observed at 79.3 and 51.8
(CH) ppm, as a singlet and as a doublet with a C-P
coupling constant of 10 Hz, respectively. The chemical
shifts of these resonances also agree well with those of
the neutral complex OsCl(η5-C5Η5){η2-HCtCC(OH)-
Ph2}(PiPr3) (δ, 82.2 and 57.2). However, they are shifted
about 100 ppm toward higher field with regard to those
of 1 (δ, 179 and 146).
Table 1. Selected Bond Lengths (Å) and Angles
(deg) for Complex 4
Os-P(1)
2.3549(14)
1.913(5)
1.856(6)
2.298(5)
2.286(6)
2.257(6)
Os-C(20)
Os-C(21)
C(1)-C(2)
C(2)-C(3)
O-C(16)
2.255(6)
2.280(5)
1.246(7)
1.358(7)
1.163(6)
Os-C(1)
Os-C(16)
Os-C(17)
Os-C(18)
Os-C(19)
M(1)*a-Os-P(1)
M(1)*-Os-C(1)
M(1)*-Os-C(16)
P(1)-Os-C(1)
123.9
123.4
126.0
91.53(15)
87.91(18)
C(1)-Os-C(16)
Os-C(1)-C(2)
Os-C(16)-O
94.0(2)
174.4(5)
175.0(5)
175.4(6)
C(1)-C(2)-C(3)
P(1)-Os-C(16)
a M(1)* is the midpoint of the C(17)-C(21) Cp ligand.
hydroxyvinylidene derivative [Os(η5-C5Η5){dCdCHC-
(OH)Ph2}(CO)(PiPr3)]PF6 (3), which dehydrates to afford
the allenylidene complex [Os(η5-C5Η5){dCdCdCPh2}-
(CO)(PiPr3)]PF6 (4) before the extinction of 2 is com-
pleted.
The isomerization of the alkynol to hydroxyvinylidene
is strongly supported by the 1H and 13C{1H} NMR
spectra of 3. In the 1H NMR spectrum, the most
noticeable resonances are two singlets at 4.00 and 3.23
ppm, corresponding to the dCH and OH protons of the
hydroxyvinylidene ligand. In the 13C{1H} NMR spec-
trum, the OsCR resonance is observed at 297.0 ppm, as
a doublet with a C-P coupling constant of 9 Hz. The
31P{1H} NMR spectrum of 3 shows a singlet at 39.8
ppm.
When the carbonylation of 1 is carried out in a
Schlenk tube for 1 min, and the resulting dichlo-
romethane solution is heated at 58 °C under argon
atmosphere, the allenylidene complex 4 is directly
obtained after 8 h.
This complex was isolated as a brown solid in 86%
yield and characterized by elemental analysis, MS, IR,
and 1H, 13C{1H}, and 31P{1H} NMR spectroscopies, and
an X-ray diffraction study. A view of the structure of
the cation of 4 is shown in Figure 1. Selected bond
distances and angles are listed in Table 1.
The 31P{1H} NMR spectrum of 2 shows a singlet at
18.9 ppm, which is shifted 9.1 ppm toward higher field
in comparison with that of 1 (δ, 38.0).
Since complex 1 is a saturated species, at first glance,
one could think that the first step for the formation of
2 is the transformation of the π-alkyne ligand from four-
electron to two-electron donor. This involves the rupture
of the overlap between the M orbital of the alkyne and
the corresponding metal fragment orbital, which is
reached when the alkyne rotates 90°. DFT calculations10
give for the process an energy of 32.7 kcal mol-1, which
is too large to be consistent with the observed reaction
rate to form the carbonylation product.
Nucleophilic attack at four-electron-donor alkyne
ligands is a particular noteworthy class of reaction.9a,c
In this context it should be mentioned that the M *
orbital is of local a2 symmetry (within the C2v group),
which prevents it from significant interaction with the
filled d metal orbitals.10 Because the M * orbital is
certainly empty, it seems reasonable to propose that the
mechanism of the carbonylation of 1 involves the initial
attack of the carbonyl group to the alkyne and its
subsequent â-transfer to the metallic center.
The geometry around the osmium center is close to
octahedral, with the cyclopentadienyl ligand occupying
three sites of a face. The angles C(16)-Os-P(1), C(1)-
In dichloromethane-d2 at room temperature and
under argon atmosphere, complex 2 evolves into the

5790 Organometallics, Vol. 23, No. 24, 2004
Asensio et al.
[OsH(η5-C5Η5){CtCC(OH}Ph2)(PHPh2)(PiPr3)]PF6 (5),
Scheme 2
which was isolated as a white solid in 87% yield.
In a manner similar to 2, the formation of 5 should
involve the initial nucleophilic attack of the phosphine
to the coordinated π-alkyne of 1 and its subsequent
â-transfer to the metallic center. The resulting diphen-
ylphosphine-triisopropylphosphine intermediate could
evolve into 5 by C(sp)-H activation of the alkyne.
In the 1H NMR spectrum of 5, in dichloromethane-d2
at room temperature, the most noticeable resonance of
the hydroxyalkynyl ligand is a singlet at 2.71 ppm,
which was assigned to the OH proton. In the high-field
region of the spectrum, the hydride ligand gives rise to
a double doublet at -12.55 ppm. In agreement with the
cisoid disposition of the hydride to both phosphorus
atoms,4h,7b the H-P coupling constants are 31.8 and
36.0 Hz. In the 13C{1H} NMR spectrum, the resonance
due to the CR atom of the hydroxyalkynyl ligand appears
at 59.9 ppm, as a double doublet with C-P coupling
constants of 23 and 28 Hz, whereas that corresponding
to the Câ atom is observed at 117.7 ppm as a singlet.
The 31P{1H} NMR spectrum contains two doublets at
22.8 (PiPr3) and -11.3 (PHPh2) ppm, with a P-P
coupling constant of 17 Hz.
In dichloromethane, complex 5 slowly evolves into its
hydroxyvinylidene isomer [Os(η5-C5Η5){dCdCHC(OH)-
Ph2}(PHPh2)(PiPr3)]PF6 (6). At 55 °C, the isomerization
is quantitative after 5 h. According to previous studies,5e
the transformation from 5 to 6 should involve the
dissociation of the hydride from 5, as a proton, and the
subsequent protonation at the Câ atom of the hydroxy-
alkynyl ligand of a neutral metal-hydroxyalkynyl spe-
cies.
Os-P(1), and C(16)-Os-C(1) are 87.91(18)°, 91.53(15)°,
and 94.0(2)°, respectively.
The diphenylallenylidene ligand is bound to the metal
in a nearly linear fashion, with Os-C(1)-C(2) and
C(1)-C(2)-C(3) angles of 174.4(5)° and 175.4(6)°, re-
spectively. The Os-C(1) and C(1)-C(2) bond lengths of
1.913(5) and 1.246(7) Å, respectively, compare well with
those reported for the previous structurally character-
ized osmium allenylidene complexes. However, the
C(1)-C(2) distance is significantly shorter than the bond
length expected for a CdC double bond (1.30 Å),
indicating a substantial contribution of the canonical
form [M]--CtC-C+Ph2 to the structure of 4. A similar
conclusion has been reached in the structural analysis
of other allenylidene complexes.1b
Complex 6 was isolated as an orange solid. In the 1H
NMR spectrum in dichloromethane-d2 at room temper-
ature, the most noticeable resonances are two singlets
at 2.60 and 2.26 ppm, corresponding to the dCH and
OH protons of the hydroxyvinylidene ligand, respec-
tively. In the 13C{1H} NMR spectrum, the OsCR reso-
nance is observed at 305.2 ppm, as a double doublet with
C-P coupling constants of 9 and 11 Hz, whereas the
Câ resonance appears at 123.1 ppm as a singlet. The
31P{1H} NMR shows two doublets at 20.8 (PiPr3) and
-16.6 (PHPh2) ppm, with a P-P coupling constant of
22 Hz.
In dichloromethane at 55 °C, complex 6 dehydrates
to afford the allenylidene [Os(η5-C5Η5)(dCdCdCPh2)-
(PHPh2)(PiPr3)]PF6 (7), which is isolated after 24 h as
a dark red solid in almost quantitative yield.
Figure 2shows a view of the structure of the cation of
7. Selected bond distances and angles are listed in Table
2. The geometry around the osmium atom is as that of
4 with C(1)-Os-P(1), C(1)-Os-P(2), and P(1)-Os-
P(2) angles of 92.08(8)°, 93.39(8)°, and 88.89(2)°, respec-
tively.
In agreement with the presence of an allenylidene
ligand in 4, its IR spectrum in Nujol shows the char-
acteristic ν(CdCdC) band for this type of ligands at
1988 cm-1, and the 13C{1H} spectrum contains a doublet
at 255.0 ppm with a C-P coupling constant of 10 Hz,
which was assigned to the CR atom, and two singlets at
195.3 and 159.6 ppm, corresponding to the Câ and Cγ
atoms, respectively. The 31P{1H} NMR spectrum of 4
shows a singlet at 37.2 ppm.
2. Preparation and Characterization of [Os(η5-
C5H5)(dCdCdCPh2)(PHPh2)(PiPr3)]PF6. From a
mechanistic point of view, it has been proposed that the
transformation alkyne-vinylidene proceeds via 1,2-
hydrogen migration on a M(η2-alkyne) intermediate or,
alternatively, through hydride-alkynyl species.3f,5e-h,12
The reactions shown in Scheme 1 are new evidence in
favor of the 1,2-hydrogen migration pathway. Scheme
2 shows the formation of an osmium allenylidene
compound, starting from the π-alkyne complex 1, via a
hydride-alkynyl intermediate. Treatment at room tem-
perature of dichloromethane solutions of 1 with 1.1
equiv of diphenylphosphine leads after 15 min
to the hydride-hydroxyalkynyl-osmium(IV) derivative
The diphenylallenylidene ligand is bound to the metal
in a nearly linear fashion with Os-C(1)-C(2) and C(1)-
C(2)-C(3) angles of 169.2(2)° and 175.7(3)°, respectively.
The Os-C(1) and C(1)-C(2) bond lengths of 1.890(2)
and 1.266(3) Å, respectively, compare well with the
related parameters in 4 and in the previous structurally
characterized osmium allenylidene complexes.4 In this
(12) See for example: (a) Silvestre, J.; Hoffmann, R. Helv. Chem.
Acta 1985, 6, 1461. (b) Bruce, M. I. Organometallics 1991, 10, 197. (c)
Wakatsuki, Y.; Koga, N.; Yamazaki, H.; Morokuma, K. J. Am. Chem.
Soc. 1994, 116, 8105. (d) Wakatsuki, Y.; Koga, N.; Werner, H.;
Morokuma, K. J. Am. Chem. Soc. 1997, 119, 360. (e) Stegmann, R.;
Frenking, G. Organometallics 1998, 17, 2089. (f) Baya, M.; Crochet,
P.; Esteruelas, M. A.; Lo´pez, A. M.; Modrego, J.; On˜ate, E. Organo-
metallics 2001, 20, 4291.

Precursor for Allenylidene Derivatives
Organometallics, Vol. 23, No. 24, 2004 5791
Scheme 3
Figure 2. Molecular diagram for the cation of [Os(η5-
C5Η5)(dCdCdCPh2)(PHPh2)(PiPr3)]PF6 (7). Thermal el-
lipsoids are shown at 50% probability.
Table 2. Selected Bond Lengths (Å) and Angles
(deg) for Complex 7
indenylidene)(CO)(PiPr3)]PF6 (8), as a result of the
isomerization of the allenylidene ligand of 4.
Os-P(1)
Os-P(2)
Os-C(1)
Os-C(37)
Os-C(38)
Os-C(39)
Os-C(40)
2.3003(6)
2.3736(6)
1.890(2)
2.300(2)
2.303(2)
2.265(3)
2.241(3)
Os-C(41)
C(1)-C(2)
C(2)-C(3)
P(1)-C(16)
P(1)-C(22)
P(1)-H(1)
2.255(2)
1.266(3)
1.349(4)
1.816(2)
1.826(2)
1.42(3)
The formation of 8 involves the initial attack of the
proton of the acid to the Câ atom of the allenylidene of
4. The addition should afford a dicationic alkenylcar-
byne intermediate a (Scheme 3), which could evolve into
8 by electrophilic substitution of an ortho proton of one
of the phenyl groups, by the CR atom of the alkenylcar-
byne unit. In agreement with the participation of the
intermediate a, we have observed that a monodeuter-
ated 3-phenyl-1-indenylidene cation 8-d1, containing a
Câ (sp2)-D bond, is obtained in the presence of CF3SO3D.
3-Phenyl-1-indenylidene-ruthenium derivatives, formed
by intramolecular rearrangement of a diphenylallen-
ylidene ligand, have been proposed as key intermediates
for the olefin metathesis catalyzed by diphenylalle-
nylidene-ruthenium derivatives.13 As far as we know,
related indenylidene-osmium compounds were unknown
until now.
The indenylidene complex 8 was isolated as a black
solid in 64% yield. The solid is a 1:1 mixture of the two
possible rotamers resulting from a high barrier to the
rotation of the indenylidene group around the Os-
indenylidene bond (8a and 8b). Figure 3 shows a view
of the structure of the rotamer containing the Câ
(sp2)-H bond of the indenylidene ligand toward the
cyclopentadienyl group (8a). Selected bond distances
and angles are listed in Table 3.
M(1)*a-Os-P(1)
M(1)*-Os-P(2)
M(1)*-Os-C(1)
P(1)-Os-P(2)
123.9
126.9
121.9
P(1)-Os-C(1)
P(2)-Os-C(1)
Os-C(1)-C(2)
C(1)-C(2)-C(3)
92.08(8)
93.39(8)
169.2(2)
175.7(3)
88.89(2)
a M(1)* is the midpoint of the C(37)-C(41) Cp ligand.
case, a substantial contribution of the canonical form
[M]--CtC-C+Ph2 to the structure of 7 can also to be
proposed.
In agreement with the presence of an allenylidene
ligand in 7, its IR spectrum in Nujol shows the char-
acteristic ν(CdCdC) band for this type of ligands at
1926 cm-1, and the 13C{1H} NMR spectrum contains a
double doublet at 257.0 ppm with C-P coupling con-
stants of 8 and 11 Hz, which was assigned to the CR
atom, and two singlets at 220.6 and 148.2 ppm, corre-
sponding to the Câ and Cγ atoms, respectively. The 31P-
{1H} NMR spectrum contains two doublets at 20.7
(PiPr3) and -17.6 (PHPh2) ppm, with a P-P coupling
constant of 24 Hz.
3. Reactions of 4 and 7 with H+. EHT-MO calcula-
tions on the model complexes [Os(η5-C5Η5)(dCdCd
CH2)(CO)(PH3)]+ and [Os(η5-C5Η5)(dCdCdCH2)(PH3)2]+
indicate that the allenylidene coordinates to the metal
centers as a σ-donor and π-acceptor ligand.4d The latter
component of the bond is stronger than the first one.
As a result, a net charge is transferred from the metallic
fragment to the allenylidene. The value of the total
charge on the allenylidene of the bisphosphine complex
[Os(η5-C5Η5)(dCdCdCH2)(PH3)2]+ is about 57% higher
than that on the allenylidene ligand of the carbonyl-
phosphine compound [Os(η5-C5Η5)(dCdCdCH2)(CO)-
(PH3)]+. In agreement with this, complexes 4 and 7 show
significant differences of behavior in the presence of
HPF6.
The geometry around the osmium center is close to
octahedral, with the cyclopentadienyl ligand occupying
three sites of a face. The angles C(1)-Os-C(16), C(16)-
Os-P, and C(1)-Os-P are 95.9(2)°, 88.30(16)°, and
97.15(14)°, respectively.
(13) See for examples: (a) Harlow, K. J.; Hill, A. F.; Wilton-Ely, J.
D. E. T. J Chem. Soc. Dalton Trans. 1999, 285. (b) Schanz, H.-J.;
Jafarpour, L.; Stevens, E. D.; Nolan, S. P. Organometallics 1999, 18,
5187. (c) Schanz, H.-J.; Jafarpour, L.; Stevens, E. D.; Nolan, S. P.
Organometallics 1999, 18, 5416. (d) Fu¨stner, A.; Guth, O.; Du¨ffels, A.;
Seidel, G.; Liebl, M.; Gabor, B.; Mynott, R. Chem. Eur. J. 2001, 7, 4811.
(e) Fu¨rstner, A.; Jeanjean, F.; Razon, P. Angew. Chem., Int. Ed. 2002,
41, 2097. (f) Fu¨rstner, A.; Radowski, K.; Wirtz, C.; Goddard, R.;
Lehmann, C. W.; Mynott, R. J. Am. Chem. Soc. 2002, 124, 7061. (g)
Opstal, T.; Verpoort, F. New. J. Chem. 2003, 27, 257. (h) Fu¨rstner, A.;
Leitner, A. Angew. Chem., Int. Ed. 2003, 42, 308. (i) Bassetti, M.;
Centola, F.; Se´meril, D.; Bruneau, C.; Dixneuf, P. H. Organometallics
2003, 22, 4459. (j) Castarlenas, R.; Dixneuf, P. H. Angew. Chem., Int.
Ed. 2003, 42, 4524.
Treatment at room temperature of dichloromethane
solutions of 4 with 2.3 equiv of HPF6‚H2O gives rise to
the indenylidene derivative [Os(η5-C5Η5)(3-phenyl-1-

5792 Organometallics, Vol. 23, No. 24, 2004
Asensio et al.
8a and 8b. The 13C{1H} NMR spectrum shows the
resonances due to the OsCR carbon atoms at 260.8 and
264.2 ppm. They appear as singlets. In solution, the
presence of an indenylidene ligand in 8 is mainly
supported by the HMBC spectrum, which shows cor-
relations between the resonances at 7.08 (1H) and 260.8
(13C{1H}) ppm and between the resonances at 6.72 (1H)
and 264.2 (13C{1H}) ppm. The 31P{1H} NMR spectrum
of 8 contains two singlets at 33.6 and 37.0 ppm.
It has been proposed that the intramolecular rear-
rangement of the diphenylallenylidene ligand into the
3-phenyl-1-indenylidene group is favored on metallic
fragments and, therefore, diphenylallenylidene groups,
poor in electron density. On the other hand, metallic
fragments or allenylidene groups rich in electron density
inhibit the isomerization.13b,i
Figure 3. Molecular diagram for the complex [Os(η5-
C5Η5)(3-phenyl-1-indenylidene)(CO)(PiPr3)]PF6 (8). Ther-
mal ellipsoids are shown at 50% probability.
In agreement with this proposal, the higher charge
on the allenylidene ligand of [Os(η5-C5H5)(dCdCdCH2)-
(PH3)2]+ with regard to that of [Os(η5-C5H5)(dCdCd
CH2)(CO)(PH3)]+ and the behavior previously observed
Table 3. Selected Bond Lengths (Å) and Angles
(deg) for the Complex 8
for complexes [Os(η5-C5H5)(dCdCdCPh2)(PiPr3)2]PF6
4d
and [Os{η5-C5H4(CH2)2PPh2}(dCdCdCPh2)(PiPr3)]PF6,4h
the treatment at room temperature of dichloromethane
solutions of 7 with 1.2 equiv of HPF6‚H2O leads to the
dicationic alkenylcarbyne derivative [Os(η5-C5H5)(t
CCHdCPh2)(PHPh2)(PiPr3)](PF6)2 (9), which does not
isomerize into an indenylidene species. The formation
of 9 according to eq 1 is additional evidence for the
participation of the intermediate a in the formation of
8, according to Scheme 3.
Os-P
2.3822(13)
1.938(5)
1.847(5)
2.322(4)
2.313(4)
2.308(4)
2.247(4)
Os-C(30)
2.269(4)
1.483(7)
1.510(6)
1.349(7)
1.492(6)
1.398(6)
Os-C(1)
Os-C(16)
Os-C(26)
Os-C(27)
Os-C(28)
Os-C(29)
C(1)-C(2)
C(1)-C(15)
C(2)-C(3)
C(3)-C(10)
C(10)-C(15)
M(1)*a-Os-P
122.9
120.8
Os-C(1)-C(2)
Os-C(1)-C(15)
C(1)-C(2)-C(3)
123.2(3)
135.8(4)
113.7(4)
M(1)*-Os-C(1)
M(1)*-Os-C(16) 123.9
P-Os-C(1)
97.15(14) C(1)-C(15)-C(10) 110.2(4)
88.30(16) C(2)-C(3)-C(10)
95.9(2)
174.6(4)
P-Os-C(16)
C(1)-Os-C(16)
Os-C(16)-O
107.0(4)
C(3)-C(10)-C(15) 107.6(4)
a M(1)* is the midpoint of the C(26)-C(30) Cp ligand.
The Os-C(1) bond length of 1.938(5) Å is between
0.04 and 0.05 Å longer than the Os-C distances found
in the complexes OsCl2(dCHCH2Ph)(CO)(PiPR3)2
Complex 9 is a result of the acid proton addition to
the Câ atom of the allenylidene ligand of 7. Its formation
agrees well with EHT-MO calculations on transition
metal allenylidene compounds, which indicate a nucleo-
philic character of the allenylidene Câ atom.2b,3b,4d,18
Complex 9 was isolated as an orange solid in 86%
yield. The presence of an alkenylcarbyne ligand in this
(1.887(9) Å),14 [OsH(κ2-O2CCH3){dC(Ph)CH2}(PiPr3)2]-
BF4 (1.895(10) and 1.882(11) Å),15 [OsH(κ2-O2CCH3)-
{dC(Me)C(OH)MePh}(PiPr3)2]BF4 (1.879(6) Å),16 and
[OsCl{dCHCH(Ph)NdCMe2}(CO)(PiPr3)2][CF3SO3] (1.890-
(10) Å),17 where an Os-C double bond has also been
1
compound is supported by the H and 13C{1H} NMR
proposed to exist. In agreement with
hybridization at C(1), the angles Os-C(1)-C(2) and
Os-C(1)-C(15) are 123.2(3)° and 135.8(4)°,
a
sp2
1
spectra. The H NMR spectrum in dichloromethane-d2
at room temperature shows a singlet at 5.10 ppm due
to the alkenylcarbyne dCH proton. In the 13C{1H} NMR
spectrum, the CR atom of the unsaturated η1-carbon
ligand gives rise to a double doublet at 296.6 ppm, with
both C-P coupling constants of 7 Hz. The Câ and Cγ
atoms display singlets at 131.2 and 175.7 ppm, respec-
tively. In contrast to 8, the HMBC spectrum of 9 does
not show correlation between the resonances at 5.10
(1H) and 296.6 (13C{1H}) ppm. The 31P{1H} NMR
spectrum of 9 contains two doublets at 31.0 (PiPr3) and
-35.2 (PHPh2) ppm, with a P-P coupling constant of
16 Hz.
respectively. The C(2)-C(3) distance of 1.349(7) Å
supports the presence of a double bond between the
C(2) and C(3) atoms of the five-membered ring of
the indenylidene ligand.
In the 1H NMR spectrum of 8 in dichloromethane-d2
at room temperature, the most noticeable resonances
are two singlets at 7.08 and 6.72 ppm, corresponding
to the Câ(sp2)-H protons of the indenylidene ligands of
(14) Esteruelas, M. A.; Lahoz, F. J.; On˜ate, E.; Oro, L. A.; Valero,
C.; Zeier, B. J. Am. Chem. Soc. 1995, 117, 7935.
(15) Buil. M. L.; Eisenstein, O.; Esteruelas, M. A.; Garc´ıa-Yebra,
C.; Gutie´rrez-Puebla, E.; Oliva´n, M.; On˜ate, E.; Ruiz, N.; Tajada, M.
A. Organometallics 1999, 18, 4949.
4. Formation of Iminiumazetidinylidenemethyl-
Osmium Derivatives. Complexes 4 and 7 show sig-
(16) Buil, M. L.; Esteruelas, M. A.; Garc´ıa-Yebra, C.; Gutie´rrez-
Puebla, E.; Oliva´n, M. Organometallics 2000, 19, 2184.
(17) Castarlenas, R.; Esteruelas, M. A.; On˜ate, E. Organometallics
2001, 20, 2294.
(18) (a) Berke, H.; Huttner, G.; Von Seyerl, J. Z. Naturforsch. 1981,
36 B, 1277. (b) Edwards, A. J.; Esteruelas, M. A.; Lahoz, F. J.; Modrego,
J.; Oro, L. A. Schrickel, J. Organometallics 1996, 15, 3556.

Precursor for Allenylidene Derivatives
Organometallics, Vol. 23, No. 24, 2004 5793
Scheme 4
Scheme 5
evolve into c by Alder-ene reactions, where the CR-Câ
double bond of b acts as enophile. The formation of the
Z-E isomeric mixtures suggests that the intermediate
c exists as mixtures in equilibrium of the isomers c1
and c2.
The [2+2] cycloadditions should occur via a polar
mechanism, by initial attack of one of the N atoms of
the carbodiimides at the Cγ atom of the allenylidene.
Thus, the difference in behavior between 4 and 7 could
be related to the presence of a carbonyl group in 4,
which enhances the electrophilic character of the Cγ
atom of the allenylidene ligand. Similar mechanisms
have been proposed for the formation of the ruthenium
counterpart [Ru(η5-C5H5){CHdCC(Ph)2N(Cy)+C+Nd
C(CH2)4CH2}(CO)(PiPr3)]+2g and for the cycloaddition of
aromatic imines to the Cγ-Cδ double bond of the
butatrienylidene ligand of the cation [Ru(η5-C5H5)(dCd
CdCdCH2)(PPh3)2]+.19
Transition metal complexes containing unsaturated
η1-carbon ligands with a four-membered heteroring are
rare. We note that E. O. Fischer has reported the
formation of the iminoazetidinylidene complex (CO)5Cr-
{dCN(Cy)C(dNCy)CH2} by reaction of (OC)5CrdC(OH)-
Me with dicyclohexylcarbodiimide.20 The alkoxycarbene
(OC)5WdC(OEt)Ph reacts with alkenylisocyanides to
give 3-aza-1,2,4-pentatriene complexes, which add a
second molecule of isocyanide to afford 1-azafulvene and
azetidin-2-ylidene derivatives by competitive [4+1] and
[3+1] cycloadditions, respectively. Azetidinylidene com-
plexes of tungsten and chromium have also been
prepared by addition of imines to carbene or alle-
nylidene compounds.21 Iron alkoxycarbene complexes
undergo formal [1+1+2] cycloadditon reactions with
isocyanides to afford iminoazetidinylidene compounds.22
Similarly, formal [2+2] cycloadditons of iron-,23 rhe-
nificant differences of behavior not only in the presence
of HPF6 but also in the presence of carbodiimides. Thus,
while the addition at room temperature of 2.0 equiv of
N,N′-dicyclohexylcarbodiimide and 1.1 equiv of N,N′-
diisopropylcarbodiimide to dichloromethane solutions
of
4 leads to the iminiumazetidinylidenemethyl
derivatives Os(η5-C5H5){CHdCC(Ph)2N(Cy)+C+Nd
C(CH2)4CH2}(CO)(PiPr3)]PF6 (10) and [Os(η5-C5H5)-
{CHdCC(Ph)2N(iPr)+C+NdC(CH3)2}(CO)(PiPr3)]PF6
(11), respectively, complex 7 is inert under the same
conditions.
Complexes 10 and 11 were isolated as orange solids
in 74% (10) and 57% (11) yield. The solids are 4:1 (10)
or 1:1 (11) mixtures of the isomers Z and E shown in
Scheme 4.
The formation of these compounds (Scheme 5) can be
rationalized as [2+2] cycloadditions between one of the
carbon-nitrogen double bonds of the carbodiimides and
the Câ-Cγ double bond of the allenylidene of 4. The
cycloadditions give intermediates b, which rapidly
(19) Bruce, M. I.; Hinterding, P.; Ke, M.; Low, P. J.; Skelton, B. W.;
White, A. H. Chem. Commun. 1997, 715.
(20) Weiss, K.; Fischer, E. O.; Mu¨ller, J. Chem. Ber. 1974, 107, 3548.
(21) (a) Barret, A. G. M.; Brock, C. P.; Sturgess, M. A. Organome-
tallics 1985, 4, 1903. (b) Aumann, R.; Kuckert, E.; Kru¨ger, C.;
Angermund, K. Angew. Chem., Int. Ed. Engl. 1987, 26, 563. (c) Fischer,
H.; Roth, G.; Reindl, D.; Troll, C. J. Organomet. Chem. 1993, 454, 133.
(22) Aumann, R.; Heinen, H. Chem. Ber. 1987, 120, 1297.
(23) Barret, A. G. M.; Mortier, J.; Sabat, M.; Sturgess, M. A.
Organometallics 1988, 7, 2553.

5794 Organometallics, Vol. 23, No. 24, 2004
Asensio et al.
Scheme 6
nium-, and manganese-vinylidene24 complexes with
imines yield azetidinylidene derivatives. Azatitanacy-
clobutane complexes have been prepared by [2+2]
cycloadditons of TidC and NdC units.25
Complexes 10 and 11 were characterized by elemental
analysis and MS, IR, and 1H, 13C{1H}, and 31P{1H}
NMR spectroscopies.
shift, 160.2 ppm. It appears as a doublet with a C-P
coupling constant of 10 Hz. The 31P{1H} NMR spectrum
of 11 shows two singlets of the same intensity at 37.2
and 25.3 ppm, one for each isomer.
5. r-Electrophilic Character of the Allenylidene
Ligand of 4. The diarylallenylidene complexes with
R-electrophilic character are characterized by their
strong trend to add RXH molecules at the CR-Câ double
bond, to afford Fischer-type alkenylcarbene deriva-
tives.2,4d Complex 4 shows the typical behavior of this
type of species (Scheme 6).
In the 1H NMR spectrum of 10a, the most noticeable
resonance is a doublet at 10.46 ppm, with a H-P
coupling constant of 3.0 Hz, corresponding to the OsCH
resonance. In agreement with the cis disposition of the
proton and CPh2 group at the OsCdC double bond, the
above mentioned resonance shows a NOE effect (18%)
with the resonance of the ortho-phenyl protons. In the
13C{1H} NMR spectrum, the OsCR resonance appears
at 159.6 ppm, as a doublet with a C-P coupling constant
of 10 Hz, whereas the NCN, Câ, and CPh2 resonances
are observed as singlets at 185.4, 143.5, and 61.0 ppm,
respectively. The 31P{1H} NMR spectrum shows a
singlet at 26.2 ppm.
In methanol as solvent, the allenylidene complex 4
evolves into the R,â-unsaturated alkoxycarbene deriva-
tive [Os(η5-C5H5){dC(OCH3)CHdCPh2}(CO)(PiPr3)]PF6
(12), which was isolated as a yellow solid in 90% yield.
The presence of the R,â-unsaturated alkoxycarbene
1
ligand in 12 is inferred from its H and 13C{1H} NMR
spectra. In the 1H NMR spectrum, the unsaturated η1-
carbon ligand gives rise to two singlets at 5.86 and 4.25
ppm, which correspond to the CHd and OCH3 protons,
respectively. In the 13C{1H} NMR spectrum, the OsCR
resonance is observed at 268.6 ppm as a singlet,
whereas the Câ and Cγ resonances appear at 138.8 and
137.9 ppm, respectively, also as singlets. The OCH3
group displays a singlet at 65.4 ppm. The 31P{1H} NMR
spectrum contains a singlet at 26.4 ppm.
In the 1H NMR spectrum of 10b, the OsCH resonance
is observed at 10.95 ppm as a doublet with a H-P
coupling constant of 3.0 Hz. In agreement with the
E-stereochemistry around the OsCdC double bond, in
this case, a NOE effect between the OsCH resonance
and that corresponding to the ortho-phenyl protons is
not observed. In the 13C{1H} NMR spectrum, the OsCR
resonance appears at 156.3 ppm as a doublet with a
C-P coupling constant of 10 Hz, whereas the resonances
corresponding to the NCN, Câ, and CPh2 carbon atoms
are observed at 187.5, 143.4, and 61.5 ppm, respectively,
as singlets. The 31P{1H} NMR spectrum shows a singlet
at 27.6 ppm.
Treatment of 12 with sodium methoxide in tetrahy-
drofuran produces the deprotonation of the olefinic
group of the alkoxycarbene ligand to give the allenyl
derivative Os(η5-C5H5){C(OCH3)dCdCPh2}(CO)(PiPr3)
(13), which was isolated as a pale yellow solid in 77%
yield. Characteristic spectroscopic features of 13 are the
CdCdC streching frequency in the IR spectrum at 1855
cm-1 and the three resonances in the 13C{1H} NMR
spectrum at 197.3 (s), 112.8 (d, J(CP) ) 11 Hz), and
103.1 (s) ppm for the Câ, CR, and Cγ allenyl carbon
atoms, respectively. A singlet at 27.5 ppm in the 31P-
{1H} NMR spectrum is also characteristic of 13.
Complex 4 also reacts with aniline. The addition at
room temperature of 1.0 equiv of this amine to dichlo-
romethane solutions of 4 affords the azoniabutadienyl
derivative [Os(η5-C5H5){C(CHdCPh2)dNHPh}(CO)(Pi-
Pr3)]PF6 (14), which was isolated as a yellow solid in
87% yield.
The 1H, 13C{1H}, and 31P{1H} NMR spectra of 11
1
agree well with those of 10. In the H NMR spectrum
the OsCH resonance of both isomers appears at 10.52
ppm, as a doublet with a H-P coupling constant of 3.7
Hz. In the 13C{1H} NMR spectrum, the OsCR resonance
of both isomers is also observed at the same chemical
(24) Terry, M. R.; Mercando, L. A.; Kelley, C.; Geoffroy, G. L.;
Nombel, P.; Lugan, N.; Mathieu, R.; Ostrander, R. L.; Owens-
Waltermire, B. E.; Rheingold, A. L. Organometallics 1994, 13, 843.
(25) Beckhaus, R.; Wagner, M.; Wang, R. Eur. J. Inorg. Chem. 1998,
253.

Precursor for Allenylidene Derivatives
Organometallics, Vol. 23, No. 24, 2004 5795
The spectroscopic data of 14 agree well with those
found for related ruthenium compounds.2h The IR
spectrum in Nujol shows a ν(NH) band at 3347 cm-1
and a ν(CdN) band at 1590 cm-1, in agreement with
the presence of a C-N double bond in the azoniabuta-
dienyl ligand. In the 1H NMR spectrum, the most
noticeable resonances are those due to the dNH and
dCH protons, which are observed as singlets at 10.20
and 6.33 ppm, respectively. In the 13C{1H} NMR spec-
trum, the resonance corresponding to the OsCR carbon
atom appears at 219.4 ppm, as a doublet with a C-P
coupling constant of 7 Hz, whereas the resonances due
to the dCH and dCPh2 carbon atoms are observed as
singlets at 138.1 and 140.8 ppm, respectively. The 31P-
{1H} NMR spectrum shows a singlet at 21.4 ppm.
The stereochemistry at the C-N double bond of the
azoniabutadienyl ligand was inferred on the basis of a
NOE experiment. The saturation of the NH resonance
increases the intensity of the CHd resonance by about
3%.
Complex 14 also undergoes a deprotonation process
in the presence of base. However, the deprotonation does
not take place at the CHdCPh2 group, as in the case of
12, but at the nitrogen atom. Thus, the treatment of
tetrahydrofuran solutions of 14 with 1.2 equiv of sodium
methoxide leads to the azabutadienyl derivative Os(η5-
C5H5){C(CHdCPh2)dNPh}(CO)(PiPr3) (15), which was
isolated as a yellow solid in 65% yield.
According to a previous theoretical study,4d the total
charge on the allenylidene ligand of the diphenylphos-
phine complex is about 57% higher than that on the
allenylidene ligand of the carbonyl compound. Thus, the
allenylidene of [Os(η5-C5H5)(dCdCdCPh2)(CO)(PiPr3)]-
PF6 is a weaker nucleophile and a stronger electrophile
than the allenylidene of [Os(η5-C5H5)(dCdCdCPh2)-
(PHPh2)(PiPr3)]PF6. In agreement with this, the allen-
ylidene ligand of the carbonyl complex isomerizes to
3-phenyl-1-indenylidene in the presence of acid, affords
iminiumazetidinylidenemethyl derivatives by reaction
with carbodiimides, and adds RXH molecules at the CRd
Câ double bond to give Fischer-type alkenylcarbene
complexes. On the other hand, the diphenylphosphine-
allenylidene complex reacts with HPF6 to give the
dicationic carbyne derivative [Os(η5-C5H5)(tCCHd
CPh2)(PHPh2)(PiPr3)](PF6)2, and it is inert toward car-
bodiimides and RXH molecules, such as alcohols and
amines.
In conclusion, the reaction of four-electron π-alkyne
complexes with a Lewis base is an easy and useful
method to prepare allenylidene-osmium complexes. The
formation mechanism of the allenylidene and its reac-
tivity depend on the electronic nature of the Lewis base.
Experimental Section
All manipulations were carried out with rigorous exclusion
of air using Schlenk techniques. Solvents were dried by the
usual procedures and used freshly distilled. [Os(η5-C5H5){η2-
HCtC-C(OH)Ph2}(PiPr3)]PF6 (1) was prepared by the pub-
lished method.10 Infrared spectra were recorded on a Nicolet
550 spectrometer as Nujol mulls on polyethylene sheets. NMR
spectra were recorded on a Varian Gemini 2000-300 MHz,
Complex 15 was characterized by elemental analysis
and MS, IR, and 1H, 13C{1H}, and 31P{1H} NMR
spectroscopies. In the IR spectrum, the most noticeable
absorption is the ν(CdN) band, which appears at 1536
cm-1. In the 1H NMR spectrum, the CHd resonance is
observed at 6.82 ppm, as a singlet. The 13C{1H} NMR
spectrum shows singlets at 176.6, 144.0, and 141.3 ppm
for the CR, Câ, and Cγ atoms, respectively, of the
azabutadienyl ligand. The 31P{1H} NMR spectrum
contains a singlet at 22.3 ppm.
1
Bruker Avance 300, or Bruker Avance 400 spectrometer. H
and 13C{1H} chemical shifts are reported relative to tetra-
methylsilane and the 31P{1H} ones relative to H3PO4 (85%).
Coupling constants J are given in hertz. C, H, N analyses were
carried out in a Perkin-Elmer 2400 CHNS/O analyzer. FAB
mass spectra analyses were performed with a VG Auto Spec
instrument. The ions were produced with standard Cs- gun
at 30 kV using 3-nitrobenzyl alcohol (NBA) as matrix.
Reaction of 1 with Carbon Monoxide: Formation of
[Os(η5-C5H5){η2-HCtCC(OH)Ph2}(CO)(PiPr3)]PF6 (2) and
[Os(η5-C5H5){dCdCHC(OH)Ph2}(CO)(PiPr3)]PF6 (3). A
brown solution of 1 (25 mg, 0.036 mmol) in 0.5 mL of CD2Cl2
was sealed under carbon monoxide atmosphere. Immediately
the NMR spectra of the resulting orange solution show the
presence of compounds 2, 3, and 4 in a 7:3:2 molar ratio.
Spectroscopic data for [Os(η5-C5H5){η2-HCtCC(OH)-
Ph2}(CO)(PiPr3)]PF6 (2). 1H NMR (300 MHz, CD2Cl2, 293
K): δ 7.50-7.28 (m, 10H, Ph), 5.74 (s, 5H C5H5), 5.05 (d, 1H,
J(HP) ) 13.2, tCH), 3.18 (s, 1H, COH), 2.55 (m, 3H, PCH),
1.20 (dd, 9H, J(HH) ) 7, J(HP) ) 14.5, PCHCH3), 1.06 (dd,
9H, J(HH) ) 6.7, J(HP) ) 15.8, PCHCH3). 31P{1H} NMR (121.4
MHz, CD2Cl2, 293 K): δ 18.9 (s, PiPr3), -144.2 (sept, J(PF) )
714, PF6). 13C{1H} NMR (75.4 MHz, CD2Cl2, 293 K): δ 179.8
(d, J(CP) ) 12, CO), 144.2, 143.1 (s, Cipso Ph), 128.7, 128.6,
128.3, 128.2, 126.6, and 126.5 (s, Ph), 88 (s, C5H5), 79.3 (s, Câ),
77.7 (s, Cγ), 51.8 (d, J(CP) ) 10, CR), 27.8 (d, J(CP) ) 30, PCH),
20.0 and 19.1 (s, PCHCH3). After 2 h, the NMR spectra of the
resulting solution show a 2, 3, and 4 mixture in a 2:6:3 molar
ratio.
In contrast to 4, complex 7 is stable in methanol, and
in dichloromethane in the presence of aniline.
Concluding Remarks
This paper reveals that the π-alkyne complex [Os(η5-
C5H5){η2-HCtCC(OH)Ph2}(PiPr3)]PF6, where the alkyne
acts as a four-electron donor, is a useful starting
material to prepare allenylidene derivatives of formula
[Os(η5-C5H5)(dCdCdCPh2)L(PiPr3)]PF6. Thus, we show
that the reactions of complex [Os(η5-C5H5){η2-HCtCC-
(OH)Ph2}(PiPr3)]PF6 with carbon monoxide and diphen-
ylphosphine lead to the mixed-ligand allenylidene com-
pounds [Os(η5-C5H5)(dCdCdCPh2)(CO)(PiPr3)]PF6 and
[Os(η5-C5H5)(dCdCdCPh2)(PHPh2)(PiPr3)]PF6, respec-
tively.
The allenylidene ligand of both complexes is a result
of the dehydration of hydroxyvinylidene intermediates.
However, the pathway for the formation of the hydroxy-
vinylidene depends on the ligand L. Carbon monoxide
favors the formation of a two-electron π-alkyne inter-
mediate, which evolves via intramolecular 1,2-hydrogen
migration. On the other hand, the formation of the
diphenylphosphine species takes place via a hydride-
hydroxyalkynyl-osmium(IV) intermediate.
Spectroscopic Data for [Os(η5-C5H5){dCdCHC(OH)-
Ph2}(CO)(PiPr3)]PF6 (3). 1H NMR (300 MHz, CD2Cl2, 293
K): δ 7.25-7.47 (m, 10H, Ph), 5.61 (s, 5H, C5H5), 4.00 (s, 1H,
dCH), 3.23 (s, 1H, OH), 2.38 (m, 9H, PCH), 1.30 (dd, 3H,
J(HH) ) 7.1, J(HP) ) 12.1, PCHCH3), 1.25 (dd, 9H, J(PH) )
7.1, J(HP) ) 11.5, PCHCH3). 31P{1H} NMR (121.4 MHz, CD2-
The ligand L also determines the electron density on
the allenylidene ligand and, therefore, its reactivity.

5796 Organometallics, Vol. 23, No. 24, 2004
Asensio et al.
Cl2, 293 K): δ 39.8 (s, PiPr3), -144.3 (sept, J(PF) ) 714, PF6).
13C{1H} NMR (75.4 MHz, CD2Cl2, 293 K): δ 297 (d, J(CP) )
9, CR) 177.2 (d, J(CP) ) 10, CO), 146.1, 144.9 (s, Cipso Ph), 130.9,
129.5, 128.3, 127.9, 127.5, and 126.2 (s, Ph), 115.2 (s, Câ), 90.0
(s, C5H5), 60.0 (s, Cγ), 28.8 (d, J(CP)) 31, PCH), 19.5 and 19.3
(s, PCHCH3).
129.1, 128.4, 128.2, 127.5, and 126.3 (s, Ph), 123.1 (s, Câ), 88.5
(s, C5H5), 66.0 (s, Cγ), 29.7 (d, J(PC) ) 30, PCH), 19.9 and 19.4
(s, PCHCH3).
Preparation of [Os(η5-C5H5)(dCdCdCPh2)(PHPh2)-
(PiPr3)]PF6 (7). A solution of 5 (150 mg, 0.16 mmol) in 6 mL
of dichloromethane was heated under reflux during 24 h. Then,
the solvent was removed. The treatment of the resulting
residue with diethyl ether afforded a dark red solid, which was
washed with diethyl ether (3 × 3 mL) and dried in vacuo.
Yield: 135 mg (91.7%). Anal. Calcd for OsC41H47P3F6: C, 52.56;
H, 5.06. Found: C, 52.41; H, 5.20. IR (Nujol, cm-1): ν(CdCd
C) 1926, ν(PF6) 840. MS (FAB+): m/z 793 (M+ + H+). 1H NMR
(300 MHz, CD2Cl2, 293 K): δ 7.75 (dd, 1H, J(PH) ) 6.6, J(P′H)
) 382.5), 7.74-7.23 (m, 20H, Ph), 5.60 (s, 5H, C5H5), 2.44 (m,
3H, PCH), 1.14 (dd, 9H, J(HH) ) 7.5, J(HP) ) 14.7, PCHCH3),
1.88 (dd, 9H, J(HH) ) 7.2, J(HP) )15.2, PCHCH3). 31P{1H}
NMR (121.4 MHz, CD2Cl2, 293 K): δ 20.7 (d, J(PP) ) 24, Pi-
Pr3), -17.6 (d, J(PP) ) 24), -144.0 (sept, J(PF) ) 716).13C-
{1H} NMR (75.4 MHz, CD2Cl2, 293 K): δ 257.0 (dd, J(CP) )
8, J(CP′) ) 11, CR), 220.6 (s, Câ), 148.2 (s, Cγ), 133.2 (d, J(CP)
) 10, Cipso PHPh2), 131.0 (d, J(CP) ) 10, Cipso PhPh2), 130.8,
130.2 (s, Cipso Ph), 129.3, 129.1, 128.9, and 128.6 (s,Ph), 88.3
(s, C5H5), 28.8 (d, J(CP) ) 29, PCH), 19.7 (s, PCHCH3).
Preparation of [Os(η5-C5H5)(CdCdCPh2)(CO)(PiPr3)2]-
PF6 (4). A brown solution of 1 (500 mg, 0.73 mmol) in 8 mL of
dichloromethane was stirred under carbon monoxide atmo-
sphere. After 5 min the carbon monoxide atmosphere was
replaced by argon, and the mixture was heated under reflux
for 8 h. The solvent was removed under reduced pressure, and
the resulting residue was treated with diethyl ether to afford
a deep brown solid, which was washed with diethyl ether (3
× 3 mL) and dried in vacuo. Yield: 430 mg (86%). Anal. Calcd
for OsC30H36OP2F6: C, 46.27; H, 4.66. Found: C, 46.10; H,
4.33. IR (Nujol, cm-1): ν(CdCdC) 1988, ν(CO) 1946. MS
(FAB+): m/z 635 (M+ + H+). 1H NMR (300 MHz, CD2Cl2, 293
K): δ 7.90-7.48 (m, 10H, Ph), 5.96 (s, 5H, C5H5), 2.40 (m, 3H,
PCH), 1.26 (dd, 9H, J(HH) ) 7.1, J(HP) ) 12.5, PCHCH3),
1.20 (dd, 9H, J(HH) ) 7.1, J(HP) ) 12.1, PCHCH3). 31P{1H}
NMR (121.4 MHz, CD2Cl2, 293 K): δ 37.2 (s, PiPr3), -144.25
(sept, J(PF) ) 709, PF6). 13C{1H} NMR (75.4 MHz, CD2Cl2,
293 K): δ 255.0 (d, J(PC) ) 10, CR), 195.3 (s, Câ), 178.9 (d,
J(CP) ) 11, CO), 159.6 (s, Cγ), 144.9 (s, Cipso Ph), 132.7, 130.9,
and 129.7 (s, Ph), 89.5 (s, C5H5), 29.6 (d, J(CP) ) 31, PCH),
19.9 and 19.5 (s, PCHCH3).
[Os(η5-C5H5)(3-phenyl-1-indenyl)(CO)(PiPr3)]PF6 (8). A
solution of 4 (159 mg, 0.20 mmol) in dichloromethane (6 mL)
was treated with HPF6 (21.2 µL, 60% in water, 0.47 mmol)
and stirred at room temperature. After 1 h, NEt3 (28.5 µL,
0.20 mmol) was added. The mixture was stirred for 30 min
and filtered through Kieselguhr. The solvent was removed
under reduced pressure. The treatment of the resulting residue
with diethyl ether leads to a black solid, which was washed
with diethyl ether (3 × 3 mL) and dried in vacuo. Complex 8
was obtained as a 1:1 mixture of the two possible rotamers.
Yield: 196 mg (64%). Anal. Calcd for OsC30F6H36OP2: C, 46.27;
H, 4.66. Found: C, 46.67; H, 4.88. IR (Nujol, cm-1): ν (CO)
Preparation of [OsH(η5-C5H5){CtC(OH)Ph2)(PHPh2}-
(PiPr3)]PF6 (5). A solution of 1 (200 mg, 0.29 mmol) in 6 mL
of dichloromethane was treated with diphenylphosphine (55.74
µL, 0.32 mmol), and the mixture was stirred for 15 min. The
color turned from brown to yellow, and the solution was filtered
through Kieselguhr. The solvent was removed in vacuo. The
addition of diethyl ether to the resulting residue led to a white
solid, which was washed with diethyl ether (3 × 3 mL) and
dried in vacuo. Yield: 243 mg (87%). Anal. Calcd for OsC41H49-
OP3F6: C, 51.57; H, 5.17. Found: C, 51.80; H, 4.88. IR (Nujol,
cm-1): ν(O-H) 3560, ν(CtC) + ν(OsH) 2119, ν(PF6) 838. MS
(FAB+): m/z 811 (M+ + H+). 1H NMR (300 MHz, CD2Cl2, 293
K): δ 7.46 (d, 1H, J(PH) ) 426.3, PHPh2), 7.39-7.35 (m, 20H,
Ph), 5.50 (s, 5H, C5H5), 2.71 (s, 1H, OH), 2.31 (m, 3H, PCH),
1.04 (dd, 9H, J(HH) )7.1, J(HP) )15.9, PCHCH3), 0.97 (dd,
9H, J(HH) ) 7.1, J(HP) ) 13.9, PCHCH3), -12.55 (dd, 1H,
J(HP) ) 31.8, J(HP′) ) 36.0, OsH). 31P{1H} NMR (121.4 MHz,
CD2Cl2, 293 K): δ 22.8 (d, J(PP) ) 17, PiPr3), -11.3(d, J(PP)
) 17, PHPh2), -144.2 (sept, J(PF) )714, PF6). 13C{1H} NMR
(75.4 MHz, CD2Cl2, 293 K): δ 148.7 (d, J(CP) ) 11, Cipso
PHPh2), 146.6 (d, J(CP) )13, Cipso PHPh2), 131.7, 130.5 (s, Cipso
Ph), 132.5, 132.4, 132.2, 132.1, 129.8, 129.4, 129.3, 127.8, and
127.5 (s, Ph), 117.7 (s, Câ), 87.1(s, C5H5), 72.7 (s, Cγ), 59.9 (dd,
J(CP) ) 23, J(CP′) ) 28, CR), 27.6 (d, J(CP) ) 31, PCH), 20.1
and 19.6 (s, PCHCH3).
1940, ν (CdC) 1530, ν(PF6) 1076. MS (FAB+): m/z 635 (M+
+
H+). 1H NMR (300 MHz, CD2Cl2, 293 K): δ 8.30-7.20 (m, 9H,
Ph), 7.08 (s, 0.5H, Câ-H), 6.72 (s, 0.5H, Câ-H), 6.10 (s, 5H,
C5H5), 3.19 (m, 3H, PCH), 1.50-0.90 (18H, PCHCH3). 31P{1H}
NMR (121.4 MHz, CD2Cl2, 293 K): δ 33.6 and 37.0 (s, PiPr3).
13C{1H} NMR (75.4 MHz, CD2Cl2, 293 K): δ 264.2 and 260.8
(s, CR), 182.3 (d, J(CP) ) 9, CO), 181.0 (d, J(CP) ) 12, CO),
152.9 (s, dCPh), 152.2 (s, Ph), 150.6 and 150.4 (s, dCH), 149.6
(s, dCPh and Ph), 141.3, 139.9, 133.4, 132.8, 132.5, 132.3,
130.8, 130.7, 130.2, 129.9, 129.5, 129.4, 128.8, 128.7, 127.1,
126.8, 121.2, and 121.0 (s, Ph), 91.6 and 90.1 (s, C5H5), 31.4
and 30.7 (d, J(CP) ) 30, PCH), 19.5, 19.3, 18.9, and 14.9 (s,
PCHCH3).
Preparation of [Os(η5-C5H5)(tC-CHdCPh2)(PHPh2)-
(PiPr3)](PF6)2 (9). A solution of 7 (152 mg, 0.16 mmol) in
dichloromethane (6 mL) was treated with HPF6 (17.2 µL, 60%
in water, 0.19 mmol) at room temperature. Immediately the
solution changed from dark red to orange. The reaction
mixture was stirred for 1 h, and the solution was reduced to
ca. 1 mL. Acetone (4 mL) was added to the resulting residue
and the mixture was filtered. The solvent was removed under
reduced pressure and the solid residue washed with diethyl
ether and dried under vacuum to afford an orange solid.
Yield: 150 mg (86%). Anal. Calcd for OsC41F2H48P4: C, 45.47;
H, 4.47. Found: C, 45.69; H, 4.54. IR (Nujol, cm-1): ν(CdC)
Preparation
of
[Os(η5-C5H5){dCdCHC(OH)Ph2}-
(PHPh2)(PiPr3)]PF6 (6). A solution of 5 (150 mg, 0.16 mmol)
in 6 mL of dichloromethane was heated under reflux. After 5
h, the resulting solution was concentrated to ca. 1 mL. The
addition of diethyl ether gave rise to the precipitation of an
orange solid, which was washed with diethyl ether (3 × 3 mL)
and dried in vacuo. Yield: 136 mg (89%). Anal. Calcd for
OsC41H49OP3F6: C, 51.57; H, 5.17. Found: C, 51.80; H, 4.88.
MS (FAB+): m/z 811 (M+ + H+). 1H NMR (300 MHz, CD2Cl2,
293 K): δ 7.50 (dd, 1H, J(HP) ) 3.9, J(HP′) ) 389.1, PHPh2),
7.52-7.24 (m, 20H, Ph), 5.63 (s, 5H, C5H5), 2.60 (s, 1H, dCH),
2.26 (s, 1H, OH), 2.42 (m, 3H, PCH), 1.16 (dd, 9H, J(HH) )
7.4, J(HP) ) 14.9, PCHCH3), 1.1 (dd, 9H, J(HH) ) 7.2, J(HP)
) 14.7, PCHCH3). 31P{1H} NMR (121.4 MHz, CD2Cl2, 293 K):
δ 20.8 (d, J(PP) ) 22, PiPr3), -16.6 (d, J(PP) ) 22, PHPh2),
-144.18 (sept, J(PF) ) 713, PF6). 13C{1H} NMR (75.4 MHz,
CD2Cl2, 293 K): δ 305.2 (dd, J(CP) ) 9, J(CP′) ) 11, CR), 135.3
(d, J(CP) ) 9, Cipso PHPh2), 134.4 (d, J(CP) ) 9, Cipso PHPh2),
133.8, 133.5 (s, Cipso Ph), 133.8, 133.6, 130.9, 130.0, 129.2,
1
1592, ν(PF6) 1058. MS (FAB+): m/z 793 (M+). H NMR (300
MHz, CD2Cl2, 293 K): δ 8.6 (dd, J(HP) ) 4.8, J(HP′) ) 382.5,
1H, PHPh2), 7.71-7.10 (m, 20H, Ph), 5.90 (s, 5H, C5H5), 5.10
(s, 1H, dCH), 2.68 (m, 3H, PCH), 1.47 (dd, 9H, J(HH) ) 7.5,
J(HP) ) 17.7, PCHCH3), 1.22 (dd, 9H, J(HH) ) 6.9, J(HP) )
15.9, PCHCH3). 31P{1H} NMR (121.4 MHz, CD2Cl2, 293 K): δ
31.0 (d, J(PP) ) 16, PiPr3), -35.2 (d, J(PP) ) 16, PHPh2). 13C-
{1H} NMR (75.4 MHz, CD2Cl2, 293 K): δ 296.6 (dd, J(CP) )
J(CP′) ) 7, CR), 175.7 (s, Cγ), 137.9, 137.2 (s, Cipso Ph), 135.3,
134.0, 133.9, 133.6, 133.5, 133.3, 132.1, 132.0, 131.4, 130.7,

Precursor for Allenylidene Derivatives
Organometallics, Vol. 23, No. 24, 2004 5797
130.6, 130.5, 130.1, 129.6, and 129.3 (s, Ph), 131.2 (s, Câ), 95.6
(s, C5H5), 30.1 (d, J(CP) ) 29, PCH), 20.0 and 19.8 (s,
PCHCH3).
130.1, 130, 129.6, 129.5, 129.4, 129.3, 129.1, 129, 128.8, 128.7,
and 126.3 (s, Ph), 89.7 and 84.3 (s, C5H5), 49.3 (s, NCH), 29.8
(d, J(CP) ) 31, PCH), 28.4 (d, J(CP) ) 30, PCH), 21.94 (s,
NCCH3), 20.1 and 19.7 (s, PCHCH3), 19.3 (s, NdCCH3).
Preparation of [Os(η5-C5H5){dC(OCH3)CHdCPh2}(CO)-
(PiPr3)]PF6 (12). A solution of 4 (150 mg, 0.19 mmol) in 10
mL of methanol was stirred during 12 h. The color turned from
brown to yellow. The solution was concentrated to ca. 1 mL,
and diethyl ether was added to afford a light yellow solid. The
solid was washed with diethyl ether and dried in vacuo.
Yield: 142 mg (90%). Anal. Calcd for OsC31H40O2P2F6: C,
45.92; H, 4.97. Found: C, 45.40; H, 4.79. IR (Nujol, cm-1):
ν(CO) 1593, ν(CdC) 1597. MS (FAB+): m/z 667 (M+ + H+).
1H NMR (300 MHz, CDCl3, 293 K): δ 7.50-7.16 (m, 10H, Ph),
5.86 (s, 1H, dCH), 5.18 (s, 5H, C5H5), 4.25 (s, 3H, OCH3), 2.36
(m, 3H, PCH), 1.29 (dd, 9H, J(HH) ) 7.2, J(HP) ) 15.0,
PCHCH3), 1.20 (dd, 9H, J(HH) ) 7.2, J(HP) ) 14.7, PCHCH3).
31P{1H} NMR (121.4 MHz, CDCl3, 293 K): δ 26.4 (s, PiPr3),
-145.1 (spt, J(PF) ) 717, PF6). 13C{1H} NMR (75.4 MHz,
CDCl3, 293 K): δ 268.6 (s, CR), 181.7 (d, J(CP) ) 8, CO), 139.9
(s, Cipso), 138.8 (s, Câ), 137.9 (s, Cγ), 131.1, 129.5, 129.4, 128.7,
128.6, and 128.4 (s, Ph), 87.4 (s, C5H5), 65.4 (s, OCH3), 30.2
(d, J(PC) ) 23, PCH), 19.8 and 19.4 (s, PCHCH3).
Preparation of [Os(η5-C5H5){CHdCC(Ph)2N(Cy)+C-
+N+C(CH2)4CH2}(CO)(PiPr3)]PF6 (10). A solution of 4 (150
mg, 0.19 mmol) in 6 mL of dichloromethane was treated with
N,N′-dicyclohexylcarbodiimide (79 mg, 0.38 mmol). The mix-
ture was stirred at room temperature for 16 h, and a color
change from brown to orange was observed. Then, the solvent
was removed under reduced pressure. The resulting residue
was treated with diethyl ether to afford an orange solid, which
was washed with diethyl ether (3 × 3 mL) and dried in vacuo.
Complex 10 was obtained as a 4:1 mixture of the Z and E
isomers. Yield: 138 mg (74%). Anal. Calcd for OsC43H58N2-
OP2F6: C, 52.43; H, 5.93; N, 2.84. Found: C, 51.93; H, 5.8; N,
2.64. IR (Nujol, cm-1): ν(CO) 1913, ν(CdN) 1674, ν(CdC) 1575.
MS (FAB+): m/z 841 (M + H+).
Spectroscopic Data for Z (10a). 1H NMR (300 MHz, CD2-
Cl2, 293 K): δ 10.46 (d, 1H, J(HP) ) 3, dCH), 7.47-7.37 (m,
10H, Ph), 5.35 (s, 5H, C5H5), 2.65-1.04 (24H, CH2 + PCH),
0.99 (dd, 18H, J(HH) ) 5.3, J(HP) ) 11, PCHCH3). 31P{1H}
NMR (121.4 MHz, CD2Cl2): δ 26.2 (s, PiPr3), -144.2 (spt, J(PF)
) 714, PF6). 13C{1H} NMR (75.4 MHz, CD2Cl2, 293 K): δ 186.1
(d, J(PC) ) 10, CO), 185.4 (s, N-C-N), 172.3 (s, CdN), 159.6
(d, J(PC) ) 10, Os-CHd), 143.5 (s, CHdC), 138.9 and 137.9
(s, Cipso Ph), 130.3, 129.9, 129.6, 129.5, 129.4, 129.2, 129.1,
129.0, 128.7, and 128.6 (s, Ph), 84.3 (s, C5H5), 61.0 (s, CPh2),
57.2 (s, NCH), 38.9, 38.3, 35.3, 33.0, and 30.2 (s, CH2), 28.3
(d, J(PC) ) 31, PCH), 19.7 and 19.3 (s, PCHCH3).
Spectroscopic Data for E (10b). 1H NMR (300 MHz, CD2-
Cl2, 293 K): δ 10.95 (d, 1H, J(HP) ) 3, dCH), 7.47-7.37 (m,
10H, Ph), 4.99 (s, 5H, C5H5), 2.65-1.04 (24H, CH2 + PCH),
0.84 (dd, 18H, J(HH) ) 5.3, J(HP) ) 10.4, PCHCH3). 31P{1H}
NMR (121.4 MHz, CD2Cl2, 293 K): δ 27.6 (s, PiPr3), -144.2
(spt, J(PF) ) 714, PF6). 13C{1H} NMR (75.4 MHz, CD2Cl2, 293
K): δ 187.5 (s, N-C-N), 184.9 (d, J(PC) ) 12, CO), 172.3 (s,
CdN), 156.3 (d, J(PC) ) 10, Os-CHd), 143.4 (s, CHdC), 138.4
and 136.5 (s, Cipso Ph), 130.6, 130.0, 129.7, 129.5, 129.4, 129.2,
129.1, 129.0, 128.7, and 128.5 (s, Ph), 84.1 (s, C5H5), 61.5 (s,
CPh2), 56.3 (s, NCH), 38.4, 37.5, 35.2, 33, 31.3, and 31.2 (s,
CH2), 30.3 (d, J(PC) ) 29, PCH), 19.6 and 19.5 (s, PCHCH3).
Preparation of Os(η5-C5H5){C(OCH3)dCdCPh2}(CO)-
(PiPr3) (13). A solution of 12 (142 mg, 0.21 mmol) in 5 mL of
tetrahydrofuran was treated with sodium methoxide (15 mg,
0.25 mmol) at room temperature. The reaction mixture was
stirred for 24 h, and the solvent was removed in vacuo. The
residue was treated with 8 mL of toluene and the resulting
suspension filtered through Kieselguhr to eliminate NaPF6.
The solvent was removed under reduced pressure and the
residue washed with pentane to give a pale yellow solid, which
was dried in vacuo. Yield: 110 mg (77%). Anal. Calcd for
OsC31H39O2P: C, 56.00; H, 5.91. Found: C, 55.88; H, 5.83. IR
(Nujol, cm-1): ν(CO) 1855, ν(dCdCdC) 1855. MS (FAB+): m/z
1
667 (M+ + 2H+). H NMR (300 MHz, C6D6, 293 K): δ 7.75-
7.24 (m, 10H, Ph), 4.9 (s, 5H, C5H5), 3.51 (s, 3H, OCH3), 2.06
(m, 3H, PCH), 0.98 (dd, 9H, J(HH) ) 7.2, J(HP) ) 13.8,
PCHCH3), 0.83 (dd, 9H, J(HH) ) 7.2, J(HP) ) 13.2, PCHCH3).
31P{1H} NMR (121.4 MHz, C6D6, 293 K): δ 27.5 (s, PiPr3). 13C-
{1H} NMR (75.4 MHz, C6D6, 293 K): δ 197.3 (s, Câ), 181.3 (d,
J(CP) ) 11, CO), 137.4 and 137.2 (s, Cipso Ph), 124.5, 124.0,
123.6, 123.5, 121.2, and 121.1 (s, Ph), 112.8 (d, J(CP) ) 11,
C(OCH3)), 103.1 (s,Cγ), 77.5 (s, C5H5), 53.0 (s, OCH3), 23.3 (d,
J(PC) ) 29, PCH), 15.1 and 14.7 (s, PCHCH3).
Preparation of [Os(η5-C5H5){CHdCC(Ph)2N(iPr)+C+
NdC(CH3)2CH2}(CO)(PiPr3)]PF6 (11). A solution of 4 (150
mg, 0.17 mmol) in 6 mL of dichloromethane was treated with
N,N′-diisopropylcarbodiimide (28.7 µL, 0.18 mmol). The mix-
ture was stirred for 15 h, and a color change from brown to
orange was observed. Solvent was evaporated in vacuo, and
the residue was treated with diethyl ether to afford a dark
orange solid, which was washed with diethyl ether (3 × 3 mL)
and dried in vacuo. Complex 11 was obtained as a 1:1 mixture
of the Z and E isomers. Yield: 85 mg (57%). Anal. Calcd for
OsC37H50ON2P2F6: C, 49.11; H, 5.57; N, 3.10. Found: C, 49.29;
H, 5.49; N, 3.10. IR (Nujol, cm-1): ν(CO) 1947, ν(CdN) 1683,
ν(CdC) 1589, ν(PF6) 840. FAB+: m/z 761 (M+ + H+). 1H NMR
(300 MHz, CD2Cl2, 293 K): δ 10.52 (d, 1H, J(HP) ) 3.7, Os-
CH), 7.87-7.38 (m, 10H, Ph), 5.95 (s, 5/2H, C5H5), 5.37 (s, 5/2H,
C5H5), 3.85 (m, 1H, NCH), 2.35 (m, 3/2H, PCH), 2.32 (d, 3H,
J(HH) ) 5.8, NCHCH3), 1.85 (m, 3/2H, PCH), 1.41 (d, 3H,
J(HH) ) 6.8, NCHCH3), 1.23 (dd, 9/2H, J(HH) ) 7.1, J(HP) )
11.1, PCHCH3), 1.18 (dd, 9/2H, J(HH) ) 7.1, J(HP) ) 11.6,
PCHCH3), 1.00 (dd, 9/2H, J(HH) ) 7.2, J(HP) ) 14.7,
PCHCH3), 0.84 (dd, 9/2H, J(HH) ) 7.0, J(HP) ) 13.9,
PCHCH3), 0.83 (s, 3H, NdCCH3), 0.80 (s, 3H, NdCCH3). 31P-
{1H} NMR (121.4 MHz, CD2Cl2, 293 K): δ 37.2 (s, PiPr3), 25.3
(s, PiPr3), -144.3 (spt, J(PF) ) 710, PF6). 13C{1H} NMR (75.4
MHz, CD2Cl2, 293 K): δ 186.2 (d, J(CP) ) 10, CO), 183.4 and
180.8 (s, NCdN), 179.1 (d, J(CP) ) 11, CO), 172.8 (s, Nd
CCH3), 160.2 (d, J(CP) ) 10, OsCR), 160.1 (s, NdCCH3), 145.1
and 141.5 (s, CHdC), 138.8 and 137.6 (s, Cipso Ph), 133.0, 131.2,
[Os(η5-C5H5){C(CHdCPh2)dNHPh}(CO)(PiPr3)]PF6 (14).
A solution of 4 (150 mg, 0.19 mmol) in dichloromethane (6 mL)
was treated with aniline (19 µL, 0.20 mmol) and the mixture
stirred for 8 h at room temperature. The solvent was concen-
trated to dryness, and the residue treated with diethyl ether
to afford a yellow solid, which was washed with diethyl ether
(3 × 3 mL) and dried in vacuo. Yield: 147 mg (87%). Anal.
Calcd for OsC36H43ONP2F6: C, 49.59; H, 4.97; N, 1.61.
Found: C, 49.37; H, 4.83; N, 1.72. IR (Nujol, cm-1): ν(NH)
3347, ν(CO) 1942, ν(CdN) 1590, ν(PF6) 852. MS (FAB+): m/z
1
728 (M+ + H+). H NMR (300 MHz, CDCl3, 293 K): δ 10.20
(br s, 1H, NH), 7.40-7.02 (m, 15H, Ph), 6.33 (s, 1H, dCH),
5.18 (s, 5H, C5H5), 2.42 (m, 3H, PCH), 1.31 (dd, 9H, J(HH) )
7.2, J(HP) ) 14.7, PCHCH3), 1.29 (dd, 9H, J(HH) ) 7.1, J(HP)
) 14.4, PCHCH3). 31P{1H} NMR (121.4 MHz, CD3Cl3, 293 K):
δ 21.4 (s, PiPr3), -143.8 (spt, J(PF) ) 704, PF6). 13C{1H} NMR
(100 MHz, CD3Cl3, 293 K): δ 219.4 (d, J(CP) ) 7, CR), 182.9
(d, J(CP) ) 10, CO), 141.1 and 140.9 (s, Cipso CPh2), 140.8 (s,
Cγ), 138.6 (s, Cipso dNPh), 138.1 (s, Câ), 130.4, 129.4, 129.2,
128.8, 128.5, 128.3, 128.2, 127.9, and 122.9 (s, Ph), 84.9 (s,
C5H5), 30.1 (d, J(PC) ) 30, PCH), 20.0 and 19.7 (s, PCHCH3).
Preparation of Os(η5-C5H5){C(CHdCPh2)dNPh}(CO)-
(PiPr3) (15). A solution of 14 (150 mg, 0.17 mmol) in 6 mL of
tetrahydrofuran was treated with sodium methoxide (11 mg,
0.20 mmol), and the mixture was stirred for 1 h. The color
turned from orange to yellow, and the solvent was evaporated.

5798 Organometallics, Vol. 23, No. 24, 2004
Table 4. Crystal Data and Data Collection and Refinement for 4, 7, and 8
Asensio et al.
4
7
8
Crystal Data
formula
molecular wt
color and habit
C
30H36F6OOsP2
C41H47F6OsP3
936.90
C30H36BF4OOsP
720.57
778.73
brown
plate
black
black
irregular prism
orthorhombic, Pna21
19.0275(9)
15.9489(7)
12.4803(6)
plate
symmetry, space group
a, Å
monoclinic, Cc
8.2926(4)
32.7606(17)
11.0558(6)
94.9650(10)
2992.3(3)
4
monoclinic, P21/c
14.1963(11)
8.1286(7)
24.719(2)
105.8000(10)
2744.7(4)
4
b, Å
c, Å
â, deg
V, Å3
3787.4(3)
4
Z
diffractometer
λ(Mo KR), Å
monochromator
scan type
Bruker Smart APEX
0.71073
graphite oriented
ω scans
µ, mm-1
4.429
3, 57
100
3.553
4.754
2θ, range deg
temp, K
3, 57
3, 57
100
100
no. of data collect
no. of unique data
no. of params/restraints
R1a[F2 > 2σ(F2)]
wR2b[all data]
Sc[all data]
18 658
45 945
26 767
6690 (Rint ) 0.0586)
353/0
7159 (Rint ) 0.0398)
355/20
9338 (Rint ) 0.0264)
471/1
0.0305
0.0180
0.0357
0.0626
0.845
0.0644
0.0410
0.837
0.783
2
2
a R1(F) ) ∑||Fo| - |Fc||/∑|Fo|. b wR2(F2) ) {∑[w(Fo2 - Fc )2]/∑[w(Fo2)2]}1/2
.
c Goof ) S ) {∑[Fo2 - Fc )2]/(n - p)}1/2, where n is the number
of reflections, and p is the number of refined parameters.
The residue was treated with toluene (9 mL), and the resulting
suspension was filtered through Kieselguhr to eliminate
NaPF6. The solvent was removed in vacuo and the residue
treated with pentane to afford a yellow solid, which was
washed with pentane (3 × 3 mL). Yield: 0.16 g (65%). Anal.
Calcd for OsC36H42ONP: C, 59.09; H, 5.83. Found: C, 59.09,
H, 5.55. IR (Nujol, cm-1): ν(CdN) 1535, ν(CO) 1895. MS
(FAB+): m/z 727 (M+ + H+). 1H NMR (300 MHz, C6D6, 293
K): δ 7.45-6.80 (m, Ph, 15H), 6.82 (s, dCH), 4.66 (s, 5H, C5H5),
2.19 (m, 3H, PCH), 1.10 (dd, 9H, J(HH) ) 7.1, J(HP) ) 13.4,
PCCH3), 0.92 (dd, 9H, J(HH) ) 7.1, J(HP) ) 13.4, PCCH3).
31P{1H} NMR (121.4 MHz, C6D6, 293 K): δ 22.3 (s, PiPr3).
13C{1H} NMR (75.4 MHz, C6D6, 293 K): δ 176.6 (s, CR), 144.0
(s, Câ), 141.3 (s, Cγ), 141.3 and 140.2 (s, Cipso Ph), 130.9, 128.7,
128.6, 128.4, 128.3, 128, 127.8, 127.7, 127.3, 125.9, and 121.3
(s, Ph), 84.5 (s, C5H5), 28.7 (d, J(CP) ) 29, PCH), 20.2 and
19.6 (s, PCHCH3).
Structural Analysis of Complexes 4, 7, and 8. X-ray data
were collected for all complexes on a Bruker Smart APEX CCD
diffractometer equipped with a normal focus, 2.4 kW sealed
tube source (molybdenum radiation, λ ) 0.71073 Å) operating
at 50 kV and 40 mA (4) or 30 mA (7, 8). Data were collected
over the complete sphere by a combination of four sets. Each
frame exposure time was 10 s, covering 0.3° in ω. Data were
corrected for absorption by using a multiscan method applied
with the SADABS26 program. The structures for all compounds
were solved by the Patterson method. Refinement, by full-
matrix least squares on F2 with SHELXL97,27 was similar for
all complexes, including isotropic and subsequently anisotropic
displacement parameters. The hydrogen atoms were observed
or calculated and refined using a restricted riding model or
freely. All the highest electronic residuals were observed in
close proximity of the Os centers and make no chemical sense.
Crystal data and details of the data collection and refinement
are given in Table 4.
Acknowledgment. Financial support from the
MCYT of Spain (Proyects BQU2002-00606 and PPQ2000-
0488-P4-02) is acknowledged. M.L.B. thanks the Span-
ish MCYT and the Universidad de Zaragoza for funding
through the “ Ramo´n y Cajal” Program.
Supporting Information Available: Tables of crystal-
lographic data and bond lengths and angles. This material is
available free of charge via the Internet at http://pubs.acs.org.
OM049479K
(26) Blessing, R. H. Acta Crystallogr. 1995, A51, 33-38. SADABS:
Area-detector absorption correction; Bruker-AXS: Madison, WI, 1996.
(27) SHELXTL Package v. 6.10; Bruker-AXS: Madison, WI, 2000.
Sheldrick, G. M. SHELXS-86 and SHELXL-97; University of Go¨ttin-
gen: Go¨ttingen, Germany, 1997.