New cyclopentadienylosmium compounds containing unsaturated carbon donor coligands: Synthesis, structure, and reactivity of Os(η5-C5H5)Cl(=C=C=CPh2)(P iPr3)

Article abstract of DOI:10.1021/om9802109

The addition of 1,1-diphenyl-2-propyn-1-ol to pentane solutions of the cyclopentadienyl compound Os(η⁵-C₅H₅)Cl(PⁱPr ₃)₂ (1) produces the displacement of a phosphine ligand from 1 and the formation of the π-alkyne complex Os(η⁵-C₅H₅)Cl{η ⁵-HC≡C-C(OH)Ph₂}(PⁱPr₃) (2), which affords the allenylidene derivative Os(η⁵-C₅H₅)Cl(=C=C=CPh₂)(P ⁱPr₃) (3) in toluene at 85°C. The structure of 3 has been determined by X-ray diffraction. The Os-C_α, C_α-C_β and C_β-C_γ bond lengths are 1.875(6), 1.222(9), and 1.344(9) A?, respectively, while the O_s-C_α-C_β and C_α-C_β-C_γ angles are 171.6(6)° and 172.0(7)°, respectively. Protonation of 3 with HBF₄·OEt₂ leads to the α,β-unsaturated carbyne [Os(η⁵-C₅H₅)Cl(≡C-CH-CPh ₂)-(PⁱPr₃)]BF₄ (4), as a result of the attack of the proton from the acid at the C_β carbon atom of the allenylidene. The nucleophilicity of this atom is also revealed by the reaction of 3 with dimethyl acetylenedicarboxylate, which leads to the allenylvinylidene Os(η⁵-C₅H₅)Cl-{=C=C(CO ₂Me)C(CO₂Me)=C=CPh₂}(PⁱPr ₃) (5). A second C₃ + C₂ coupling process is the formation of the pentatrienyl complex Os(η⁵-C₅H₅){(3-5-η)CH ₂CHC=C=CPh₂}(PⁱPr₃) (6) by reaction of 3 with CH₂=CHMgBr. Complex 3 also reacts with KI to give Os(η⁵-C₅H₅)I(=C=C=CPh₂)(P ⁱPr₃)(7). The reduction of the C_β-C_γ double bond of the allenylidene ligand of 3, to form the vinylidene complex Os(η⁵-C₅H₅)Cl(=C=CH-CHPh ₂)(PⁱPr₃) (8), has been carried out in the presence of NaBH₄ and methanol.

Full text of DOI:10.1021/om9802109

Organometallics 1998, 17, 3479-3486
3479
New Cyclop en ta d ien ylosm iu m Com p ou n d s Con ta in in g
Un sa tu r a ted Ca r bon Don or Coliga n d s: Syn th esis,
Str u ctu r e, a n d Rea ctivity of
Os(η5-C5H5)Cl(dCdCdCP h 2)(P iP r 3)
Pascale Crochet, Miguel A. Esteruelas,* Ana M. Lo´pez, Natividad Ruiz, and
J ose´ I. Tolosa
Departamento de Quı´mica Inorga´nica, Instituto de Ciencia de Materiales de Arago´n,
Universidad de ZaragozasConsejo Superior de Investigaciones Cientı´ficas,
50009 Zaragoza, Spain
Received March 19, 1998
The addition of 1,1-diphenyl-2-propyn-1-ol to pentane solutions of the cyclopentadienyl
compound Os(η5-C5H5)Cl(PiPr3)2 (1) produces the displacement of a phosphine ligand from
1 and the formation of the π-alkyne complex Os(η5-C5H5)Cl{η2-HCtC-C(OH)Ph2}(PiPr3)
(2), which affords the allenylidene derivative Os(η5-C5H5)Cl(dCdCdCPh2)(PiPr3) (3) in
toluene at 85 °C. The structure of 3 has been determined by X-ray diffraction. The Os-CR,
CR-Câ, and Câ-Cγ bond lengths are 1.875(6), 1.222(9), and 1.344(9) Å, respectively, while
the Os-CR-Câ and CR-Câ-Cγ angles are 171.6(6)° and 172.0(7)°, respectively. Protonation
of 3 with HBF4‚OEt2 leads to the R,â-unsaturated carbyne [Os(η5-C5H5)Cl(tC-CHdCPh2)-
(PiPr3)]BF4 (4), as a result of the attack of the proton from the acid at the Câ carbon atom
of the allenylidene. The nucleophilicity of this atom is also revealed by the reaction of 3
with dimethyl acetylenedicarboxylate, which leads to the allenylvinylidene Os(η5-C5H5)Cl-
{dCdC(CO2Me)C(CO2Me)dCdCPh2}(PiPr3) (5). A second C3 + C2 coupling process is the
formation of the pentatrienyl complex Os(η5-C5H5){(3-5-η)CH2CHCdCdCPh2}(PiPr3) (6) by
reaction of 3 with CH2dCHMgBr. Complex 3 also reacts with KI to give Os(η5-
C5H5)I(dCdCdCPh2)(PiPr3) (7). The reduction of the Câ-Cγ double bond of the allenylidene
ligand of 3, to form the vinylidene complex Os(η5-C5H5)Cl(dCdCH-CHPh2)(PiPr3) (8), has
been carried out in the presence of NaBH4 and methanol.
In tr od u ction
study on the chemical properties of the six-coordinate
osmium (IV) complex OsH2Cl2(PiPr3)2,5 we have ob-
served that its reaction with cyclopentadienylthallium
leads to Os(η5-C5H5)Cl(PiPr3)2, which is also a useful
starting material for the preparation of new cyclopen-
tadienylosmium compounds.6
The chemistry of the Os(η5-C5H5) unit is a little-
known field1 due to the lack of convenient osmium
synthetic precursors2 and the higher kinetic stability
of the CpOsL3 compounds in comparison with the
related iron and ruthenium species.3
We have recently reported that the five-coordinate
complex OsHCl(CO)(PiPr3)2 reacts with cyclopentadiene
to afford OsH(η5-C5H5)(CO)(PiPr3), which has been the
starting point for new half-sandwich osmium complexes
including hydrido, halide, vinylidene, and alkenylvi-
nylidene derivatives.4 Subsequently, as a part of our
The chemical behavior of Os(η5-C5H5)Cl(PiPr3)2 is a
result of two factors: the high basicity of the metallic
center, as a consequence of the presence of the strong
donor phosphine and the chlorine ligands in the com-
plex, and the large steric hindrance experienced by the
triisopropylphosphine groups, which are mutually cis
disposed. This mixture allows access to reactive points
on the osmium center by activation of Os-P and Os-
Cl bonds. In polar solvents such as methanol and
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S0276-7333(98)00210-6 CCC: $15.00 © 1998 American Chemical Society
Publication on Web 07/03/1998

3480 Organometallics, Vol. 17, No. 16, 1998
Crochet et al.
Sch em e 1
acetone, the dissociation of the chlorine ligand occurs,
and the resulting metallic fragment is capable of
activating a methyl C-H bond of a triisopropylphos-
phine to give [OsH(η5-C5H5){CH2CH(CH3)PiPr2}-
(PiPr3)]+. On the other hand, in pentane and toluene,
the splitting of an Os-P bond is favored, and the
reactions of Os(η5-C5H5)Cl(PiPr3)2 with olefins and
alkynes lead to π-olefin and π-alkyne complexes.6
In 1982, Selegue illustrated that propargylic alcohols
HCtC-CRR′OH can be converted quite smoothly into
a CdCdCRR′ unit in the coordination sphere of an
electron-rich transition-metal center by elimination of
water.7 Since then, a variety of allenylidene-metal
complexes has been prepared, the elements of chromium
and manganese triads, as well as rhodium and ruthe-
nium, thereby playing a dominant role.8,9
Allenylidene complexes of the third-row platinum
group metals are rare. For osmium, Gimeno and co-
workers have reported that the reactions of Os(η5-C9H7)-
Cl(PPh3)2 with propargylic alcohols in the presence of
NaPF6 lead to [Os(η5-C9H7)(dCdCdCR2)(PPh3)2]PF6 (R2
) Ph2, C12H8),10 and we have described the formation
Os{C[C(dCH2)C(O)OCH3]dCdCPh2}Cl(CO)(PiPr3)2 via
the intermediate Os{C(CO2CH3)dCH2}Cl(dCdCdCPh2)-
(CO)(PiPr3)2, which is isolated as a mixture of two
different isomers.11 Other neutral osmium-allenylidene
compounds are not known. For iridium, the neutral
allenylidene complex IrCl(dCdCdCPh2)(PiPr3)2 has
been reported by Werner and co-workers. Its formation
involves alkynylhydridoiridium (III) or alternatively
square-planar hydroxyvinylidene intermediates, which
are catalytically converted into the allenylidene in the
presence of trifluoroacetic acid.12 We had previously
observed the formation of square-planar cationic species
containing an IrdCdCdCPh2 unit as a result of the
protonation of Ir{CtC-C(OH)Ph2}(diene)(PR3) com-
plexes.13 To the best of our knowledge, platinum-
allenylidene compounds have not been reported.
The lability of one of the two Os-P bonds in Os(η5-
C5H5)Cl(PiPr3)2 prompted us to carry out the reaction
of this complex with 1,1-diphenyl-2-propyn-1-ol, to
prepare Os(η5-C5H5)Cl(dCdCdCPh2)(PiPr3), and to study
the influence of the Os(η5-C5H5) unit on the chemical
properties of the allenylidene ligand. In this paper, we
report the synthesis, the structure, and some reactivity
of this complex.
of the complex [Os{C[C(O)OCH3]dCH2}(dCdCdCPh2)-
(CO)(PiPr3)2]BF4, which in the presence of NaCl and in
toluene at 60 °C evolves to the allenyl derivative
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Gimeno, J .; Lastra, E. J . Organomet. Chem. 1994, 474, C27. (n)
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C.; Leroux, F. J . Organomet. Chem. 1995, 490, 221. (s) Touchard, D.;
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Resu lts a n d Discu ssion
1. Syn th esis a n d X-r a y Str u ctu r e of Os(η5-C5H5)-
Cl(dCdCdCP h 2)(P iP r 3). In agreement with the ten-
dency shown by the complex Os(η5-C5H5)Cl(PiPr3)2 (1)
to release a phosphine ligand, the treatment of this
compound with 1 equiv of 1,1-diphenyl-2-propyn-1-ol in
pentane at room temperature led to the π-alkynol
complex Os(η5-C5H5)Cl{η2-HCtC-C(OH)Ph2}(PiPr3) (2,
Scheme 1), which was isolated as a violet solid in 80%
yield.
The π-coordination of the alkynol in 2 is strongly
supported by the IR spectrum, in which the CtC
stretching frequency is found at 1801 cm-1, shifted 316
cm-1 to lower wavenumbers in comparison with the Ct
(11) Bohanna, C.; Callejas, B.; Edwards, A. J .; Esteruelas, M. A.;
Lahoz, F. J .; Oro, L. A.; Ruiz, N.; Valero, C. Organometallics 1998,
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1997, 16, 4077.
(13) Esteruelas, M. A.; Oro, L. A.; Schrickel, J . Organometallics
1997, 16, 796.

Study of Os(η5-C5H5)Cl(dCdCdCPh2)(PiPr3)
Organometallics, Vol. 17, No. 16, 1998 3481
is statistically identical with that found in the cationic
indenyl complex [Os(η5-C9H7)(dCdCdCPh2)(PPh3)2]PF6
[1.895(4) Å]10 and about 0.05 Å shorter than the related
bond length in [Os{C[C(O)OCH3]dCH2}(dCdCdCPh2)-
(CO)(PiPr3)2]BF4 [1.947(6) Å].11 The C(15)-C(16) dis-
tance [1.222(9) Å] compares well with those found in
the previously reported two osmium-allenylidene com-
pounds [1.265(6) and 1.250(8) Å, respectively]. How-
ever, it is significantly shorter than the bond length
expected for a carbon-carbon double bond (1.30 Å),15
indicating a substantial contribution of the canonical
form [Os]--CtC-C+Ph2 to the structure of 3. A similar
conclusion has been reached in the structural analysis
of the other allenylidene complexes.10,11
F igu r e 1. Molecular diagram of the complex Os(η5-
C5H5)Cl(dCdCdCPh2)(PiPr3) (3). Thermal ellipsoids are
shown at 50% probability.
In agreement with the presence of the allenylidene
ligand in 3, the IR spectrum shows the characteristic
ν(CdCdC) band for this type of ligands at 1874 cm-1
,
and the 13C{1H} NMR spectrum contains a doublet at
225.1 ppm with a P-C coupling constant of 15.2 Hz,
which was assigned to the R-carbon atom, and two
singlets at 238.5 and 129.1 ppm, corresponding to â- and
γ-carbon atoms, respectively.
Ta ble 1. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for th e Com p lex Os(η5-C5H5)Cl
(dCdCdCP h 2)(P iP r 3) (3)
Os-C(1)
Os-C(2)
Os-C(3)
Os-C(4)
Os-C(5)
2.278(6)
2.344(7)
2.330(6)
2.273(7)
2.262(7)
Os-P
2.311(2)
2.457(2)
1.875(6)
1.222(9)
1.344(9)
Os-Cl
Os-C(15)
C(15)-C(16)
C(16)-C(17)
In addition, the atypical chemical shift for the â-car-
bon atom, which appears at lower field than even that
for the R-carbon atom, should be noted. This unex-
pected finding has been previously observed in the
µ-dicyanoallenylidene complex (η5-C5H5)2Fe2(µ-CO)(µ-
P-Os-Cl
86.42(5) Os-C(15)-C(16)
171.6(6)
P-Os-C(15)
P-Os-G(1)a
Cl-Os-C(15)
Cl-Os-G(1)a
C(15)-Os-G(1)a
84.5(2)
132.8(2)
104.1(2)
118.0(2)
122.2(3)
C(15)-C(16)-C(17) 172.0(7)
C(16)-C(17)-C(18) 118.6(6)
C(16)-C(17)-C(24) 120.7(6)
C(18)-C(17)-C(24) 120.6(6)
dppe){µ-CdCdC(CN)2} and in the complexes Cp* Fe2-
2
(µ-CdCdCR′R′′)(µ-CO)(CO)2.16
2. Rea ctivity of 3. EHT-MO calculations on the
allenylidene complexes Mn(η5-C5H5)(CO)2(dCdCdCH2),17
[Rh2(µ-OOCH)(µ-σ,σ-CdCdCH2)(CO)2(PH3)2]+,8v [Ru-
(η5-C5H5)(dCdCdCH2)(CO)(PH3)]+,18 and [Ru(η5-C9H7)-
(dCdCdCH2)(PH3)2]+ 10 suggest, in all the cases, that
the CR and Cγ carbon atoms of the allenylidene unit are
electrophilic centers, while the Câ carbon atom is
nucleophilic. In agreement with the electrophilic char-
acter of the CR and Cγ carbon atoms, cationic alle-
nylidene-ruthenium(II) complexes and the cationic
a
G(1) is the midpoint of the C(1)-C(5) Cp ligand.
C stretching frequency in the free alkyne (2117 cm-1).14
In the 13C{1H} NMR spectrum, the resonance of the
HCt carbon atom appears at 122.9 ppm as a singlet,
whereas the other acetylenic carbon atom gives rise at
82.2 ppm to a doublet with a P-C coupling constant of
1
6.5 Hz. In the H NMR spectrum, the most noticeable
resonances are a singlet at 6.93 ppm corresponding to
the O-H proton and a doublet at 4.32 ppm with a P-H
coupling constant of 9.0 Hz due to the HCt proton.
In toluene at room temperature, complex 2 is stable.
However, at 85 °C, it evolves into the allenylidene
derivative Os(η5-C5H5)Cl(dCdCdCPh2)(PiPr3) (3) in
quantitative yield after 15 h. The reaction most prob-
ably involves the formation of a hydroxyvinylidene inter-
mediate, which dehydrates spontaneously7 (Scheme 1).
Complex 3 was isolated as a green solid and charac-
terized by elemental analysis, IR, 1H, 31P{1H}, and 13C-
{1H} spectroscopies, and an X-ray diffraction study. A
view of the molecular geometry is shown in Figure 1.
Selected bond distances and angles are listed in Table
1. The geometry around the osmium center is close to
octahedral, with the cyclopentadienyl ligand occupying
three sites of a face. The angles P-Os-Cl, P-Os-
C(15), and Cl-Os-C(15) are 86.42(5)°, 84.5(2)°, and
104.1(2)°, respectively.
allenylidene-osmium(II) compound [Os{C[C(O)OCH3]d
CH2}(dCdCdCPh2)(CO)(PiPr3)2]BF4 are quite reactive
toward nucleophiles. Work by Dixneuf and co-work-
ers,8a,e,f,n,p,s Gimeno and co-workers,8j,k,m,9e-h,10 and our
group8w,11,18 has shown that such compounds are easily
attacked by alcohols, thiols, alcoholates, acetylides,
phosphines, and amines. In addition, Werner and co-
workers have reported the formation of γ-functionalized
alkynyl groups by migratory insertion of an allenylidene
unit into Rh-OR (R ) Ph, CH3CO) bonds of neutral
rhodium species.9i,19
The behavior of 3 toward nucleophilic reagents mark-
edly differs from that previously mentioned. The alle-
nylidene ligand is inert in the presence of alcohols,
diphenylphosphine, benzophenone imine, pyrazole, and
(15) Orpen, A. G.; Brammer, L.; Allen, F. H.; Kennard, O.; Watson,
D. G.; Taylor, R. J . Chem. Soc., Dalton Trans. 1989, S1.
(16) (a) Etienne, M.; Toupet, L. J . Chem. Soc., Chem. Commun.
1989, 1110. (b) Akita, M.; Kato, S.-I.; Terada, M.; Masaki, Y.; Tanaka,
M.; Moro-oka, Y. Organometallics 1997, 16, 2392.
(17) Berke, H.; Huttner, G.; von Seyerl, J . Z. Naturforsch. 1981, 366,
1277.
The diphenylallenylidene ligand is bound to the metal
in a nearly linear fashion, with Os-C(15)-C(16) and
C(15)-C(16)-C(17) angles of 171.6(6)° and 172.0(7)°,
respectively. The Os-C(15) bond length of 1.875(6) Å
(18) Esteruelas, M. A.; Go´mez, A. V.; Lo´pez, A. M.; Modrego, J .;
On˜ate, E. Organometallics 1997, 16, 5826.
(14) Esteruelas, M. A.; Lahoz, F. J .; Mart´ın, M.; On˜ate, E.; Oro, L.
A. Organometallics 1997, 16, 4572.
(19) Werner, H.; Wiedemann, R.; Laubender, M.; Wolf, J .; Wind-
mu¨ller, B. J . Chem. Soc., Chem. Commun. 1996, 1413.

3482 Organometallics, Vol. 17, No. 16, 1998
Crochet et al.
Sch em e 2
acetate. In methanol, the dissociation of the chlorine
and the subsequent activation of a methyl C-H bond
of the phosphine are also not observed. However, in
agreement with the expected nucleophilic character of
the Câ carbon atom, complex 3 reacts with 1 equiv of
HBF4‚OEt2 to afford the R,â-unsaturated carbyne de-
rivative [Os(η5-C5H5)Cl{tC-CHdCPh2}(PiPr3)]BF4 (4),
which is a result of the attack of the proton from the
acid to the Câ carbon atom of the allenylidene ligand
(eq 1). We note that Kolobova and co-workers have
previously reported the synthesis of related manganese
complexes by protonation of the corresponding alle-
nylidene starting materials.20
Although binuclear µ-alkenylcarbyne complexes are
well known,21 the mononuclear alkenylcarbyne com-
pounds are rare, in particular those containing osmium.
The latter have been prepared using dihydridoosmium-
(IV) complexes and alkynols as precursors.5b,22 Re-
cently, we have also observed that the protonation of
R,â-unsaturated vinylidene-osmium(II) compounds af-
fords R,â-unsaturated carbyne derivatives.6 Previously,
the same method of synthesis has been used to prepare
related compounds of manganese,23 tungsten,24 and
rhodium.25
singlets. The 31P{1H} NMR spectrum shows a singlet
at 37.7 ppm.
The nucleophilicity of the Câ carbon atom of the
allenylidene of 3 is also revealed by its reaction with
the electron-withdrawing alkyne dimethyl acetylenedi-
carboxylate. This alkyne contains two ester function-
alities that draw electron density from the carbon-
carbon triple bond, activating it toward nucleophilic
attack by the electron-rich allenylidene Câ atom. Thus,
the treatment of 3 with dimethyl acetylenedicarboxylate
in toluene under reflux leads, after 20 h, to the alle-
nylvinylidene Os(η5-C5H5)Cl{dCdC(CO2CH3)C(CO2-
CH3)dCdCPh2}(PiPr3) (5). The insertion of the alkyne
into the CR-Câ double bond of the allenylidene can be
rationalized as a stepwise cycloaddition to form an η1-
cyclobutenyl intermediate, which rapidly ring-opens to
The protonation of 3 to give 4 was carried out in
dichloromethane-d2 as solvent, and complex 4 was
isolated as a green solid in 93% yield. The IR spectrum
in Nujol shows the absorption due to the [BF4]- anion
with Td symmetry centered at 1065 cm-1, which indi-
cates that this anion is not coordinated to the metallic
1
center. In the H NMR spectrum in dichloromethane-
d2, the most noticeable resonance is a singlet at 6.01
ppm, assigned to the dCH proton. In the 13C{1H} NMR
spectrum, the resonance due to the sp carbon atom of
the η1-unsaturated ligand appears at 289.1 ppm as a
doublet, with a P-C coupling constant of 10.1 Hz,
whereas the resonances of the sp2 carbon atoms are
observed at 169.1 (dCPh2) and 135.6 (CHd) ppm as
form the allenylvinylidene product (Scheme 2).
A
similar reaction pathway has been previously proposed
for the addition of dimethyl acetylenedicarboxylate to
the vinylidene ligand of mer-(dppe)(OC)3WdCdCHPh,
which yields an alkenylvinylidene derivative.26
Complex 5 was isolated as an orange solid in 72%
yield. The IR spectrum in Nujol shows the CdCdC
stretching frequency at 1719 cm-1, along with two ν-
(CO) bands at 1678 and 1576 cm-1 corresponding to the
(20) Kolobova, N. E.; Ivanov, L. L.; Zhvanko, O. S.; Khitrova, O. M.;
Batsanov, A. S.; Struchkov, Yu. T. J . Organomet. Chem. 1984, 262,
39.
(21) (a) Nitay, M.; Priester, W.; Rosenblum, M. J . Am. Chem. Soc.
1978, 100, 3620. (b) Ustynyuk, N. A.; Vinogradova, V. N.; Andrianov,
V. G.; Struchkov, Yu. T. J . Organomet. Chem. 1984, 268, 73. (c) Casey,
C. P.; Marder, S. R. Organometallics 1985, 4, 411. (d) Casey, C. P.;
Konings, M. S.; Palermo, R. E.; Colborn, R. E. J . Am. Chem. Soc. 1985,
107, 5296. (e) Casey, C. P.; Konings, M. S.; Marder, S. R. Polyhedron
1988, 7, 881. (f) Casey, C. P.; Konings, M. S.; Marder, S. R. J .
Organomet. Chem. 1988, 345, 125. (g) Etienne, M.; Talarmin, J .;
Toupet, L. Organometallics 1992, 11, 2058.
(22) Weber, B.; Steinert, P.; Windmu¨ller, B.; Wolf, J .; Werner, H.
J . Chem. Soc., Chem. Commun. 1994, 2595.
(23) (a) Kelley, C.; Lugan, N.; Terry, M. R.; Geoffroy, G. L.; Haggerty,
B. S.; Rheingold, A. L. J . Am. Chem. Soc. 1992, 114, 6735. (b) Terry,
M. R.; Kelley, C.; Lugan, N.; Geoffroy, G. L.; Haggerty, B. S.; Rheingold,
A. L. Organometallics 1993, 12, 3607.
1
carboxylato groups. In the H NMR spectrum, the most
noticeable resonances are two singlets at 3.52 and 3.37
ppm due to the methyl protons of the η1-unsaturated
carbon ligand. The presence of an allenylvinylidene
ligand in 5 is also supported by the 13C{1H} NMR
spectrum, which contains at 286.6 ppm a doublet with
a P-C coupling constant of 12.5 Hz, due to the CR
carbon atom, and at 215.5 ppm a singlet corresponding
to the central carbon atom of the allenyl unit. The Câ
carbon atom of the vinylidene and the CR and Cγ carbon
atoms of allenyl unit are observed as singlets at 114.3,
(24) Zhang, L.; Gamasa, M. P.; Gimeno, J .; Carbajo, R. J .; Lo´pez-
Ortiz, F.; Lanfranchi, M.; Tiripicchio, A. Organometallics 1996, 15,
4724.
(25) Rappert, T.; Nu¨rnberg, O.; Mahr, N.; Wolf, J .; Werner, H.
Organometallics 1992, 11, 4156.
(26) Gamble, A. S.; Birdwhistell, K. R.; Templeton, J . L. Organo-
metallics 1988, 7, 1046.

Study of Os(η5-C5H5)Cl(dCdCdCPh2)(PiPr3)
Organometallics, Vol. 17, No. 16, 1998 3483
Sch em e 3
pathway leading to 6, namely the direct attack of the
vinyl nucleophile to the CR carbon atom of the alle-
nylidene ligand followed by elimination of chloride with
concomitant η1 to η3 rearrangement, could be also
considered but seems less likely, since the allenylidene
ligand is inert in the presence of nucleophiles, as has
been previously mentioned.
To confirm the lability of the chloro ligand in 3, we
have also carried out the reaction of this complex with
potassium iodide. As expected, the addition of this salt
to 3 in methanol affords the iodo complex Os(η5-
C5H5)I(dCdCdCPh2)(PiPr3) (7, in Scheme 3), which was
isolated as a brown solid in 64% yield.
The most characteristic spectroscopic features of 7
are, in the IR spectrum, the ν(CdCdC) band at 1872
cm-1 and, in the 13C{1H} NMR spectrum, a doublet at
234.1 ppm with a P-C coupling constant of 14.3 Hz,
which was assigned to the CR carbon atom, and two
singlets at 243.3 and 132.0 ppm, corresponding to the
Câ and Cγ carbon atoms, respectively. As for 3, the
resonance due to the Câ atoms appears at lower field
than that due to the CR carbon atom.
112.5, and 92.7 ppm. The 31P{1H} NMR spectrum
shows a singlet at 21.9 ppm.
The formation of 5 according to Scheme 2 is a novel
C3 + C2 coupling reaction. A second C3 + C2 coupling
process is shown in Scheme 3. Treatment of a solution
of 3 in toluene with 1 equiv of CH2dCHMgBr in
tetrahydrofuran leads to a rapid change of color from
green to yellow and finally to the isolation of yellow
microcrystals of the pentatrienyl complex Os(η5-C5H5)-
{(3-5-η)CH2CHCdCdCPh2}(PiPr3) (6) in 73% yield.
The IR spectrum of 6 shows the characteristic CdCd
C stretching frequency at 1939 cm-1. The resonances
corresponding to the allyl protons are observed, in the
1H NMR spectrum, as three multiplets at 3.98 (Hmeso),
2.92 (Hsyn), and 2.01 (Hanti) ppm. The 13C{1H} NMR
spectrum displays two low-field signals for the allene-
like carbon atoms dCd and dCPh2 at 192.4 and 103.2
ppm, which appear as doublets with P-C coupling
constants of 3.8 and 1.8 Hz, respectively, and three
resonances due to the allyl carbons at 91.4 (Cd), 33.1
(CH), and 11.8 (CH2) ppm, which are also observed as
doublets but with P-C coupling constants of 11.5, 2.8,
and 6.0 Hz, respectively.
A general procedure to generate ruthenium and
osmium hydrido compounds is the treatment of chloro
precursors with NaBH4 in the presence of methanol.5a,30
However, an unexpected reaction occurs if a toluene
solution of 3 is treated with NaBH4 and subsequently
with some drops of methanol. Under these conditions,
the substitution of the chloro ligand by hydride does not
take place, but the formation of the vinylidene deriva-
tive Os(η5-C5H5)Cl(dCdCH-CHPh2)(PiPr3) (8), as a
result of the reduction of the Câ-Cγ double bond of the
allenylidene ligand of 3, is observed (eq 2). We note
that, in contrast to the reaction shown in eq 2, the
reduction of the neutral allenylidene complexes MCl(d
CdCdCPh2)(PiPr3)2 (M ) Rh, Ir) with molecular hy-
drogen leads to allene compounds.12,31
Complex 6 is a rare case of a transition-metal pen-
tatrienyl complex. We note that related ruthenium27
and rhodium28 compounds have been previously pre-
pared by a similar procedure. With regard to the
mechanism of formation of the pentatrienyl ligand, we
assume that initially a nucleophilic substitution of the
chloro ligand takes place and a vinylmetal intermediate
is generated. This could rearrange by migratory inser-
tion of the allenylidene ligand into the Os-CHdCH2
bond to give the final product. In this context, it should
be noted that the rhodium complexes trans-RhCl(dCd
Complex 8 was isolated as an orange solid in 65%
yield. The IR spectrum in Nujol shows the ν(CdC) band
1
due to the vinylidene ligand at 1656 cm-1. In the H
NMR spectrum, the most noticeable resonances are two
doublets at 5.24 and 2.38 ppm with a H-H coupling
constant of 10.3 Hz, corresponding to the dCH and
-CH- protons, respectively. In the 13C{1H} NMR
spectrum, the resonance due to the CR carbon atom of
the vinylidene appears at 283.7 ppm as a doublet with
a P-C coupling constant of 13.4 Hz, whereas the signal
corresponding to the Câ carbon atom is observed at 126.1
ppm as a singlet, and the resonance due to the CHPh2
carbon atom appears at 40.2 ppm, also as a singlet. The
31P{1H} NMR spectrum shows a singlet at 20.4 ppm.
t
CHR)(PiPr3)2 (R ) Bu, Ph) react with CH2dCHMgBr
to afford trans-Rh(CHdCH2)(dCdCHR)(PiPr3)2, which
upon heating to 50 °C in benzene isomerize to give the
butadienyl derivatives Rh{(2-4-η)-CH2CHCdCHR}-
(PiPr3)2.29
Taking into account the kinetic inertia of the CpOsL3
complexes toward substitution reactions, an alternative
(27) Braun, T.; Meuer, P.; Werner, H. Organometallics 1996, 15,
4075.
(28) (a) Wiedemann, R.; Steinert, P.; Gevert, O.; Werner, H. J . Am.
Chem. Soc. 1996, 118, 2495. (b) Wiedemann, R.; Fleischer, R.; Stalke,
D.; Werner, H. Organometallics 1997, 16, 866.
(29) Wiedemann, R.; Wolf, J .; Werner, H. Angew. Chem., Int. Ed.
Engl. 1995, 34, 1244.
(30) (a) Werner, H.; Esteruelas, M. A.; Meyer, U.; Wrackmeyer, B.
Chem. Ber. 1987, 120, 11. (b) Esteruelas, M. A.; Valero, C.; Oro, L. A.;
Meyer, U.; Werner, H. Inorg. Chem. 1991, 30, 1159.
(31) Werner, H.; Laubender, M.; Wiedemann, R.; Windmu¨ller, B.
Angew. Chem., Int. Ed. Engl. 1996, 35, 1237.

3484 Organometallics, Vol. 17, No. 16, 1998
Crochet et al.
300, Varian Gemini 2000 (300 MHz), or a Bruker ARX 300.
1H and 13C{1H} chemical shifts were measured relative to
partially deuterated solvent peaks but are reported relative
to tetramethylsilane. 31P{1H} chemical shifts are reported
relative to H3PO4 (85%). Coupling constants J are given in
hertz. C, H, and N analyses were carried out in a Perkin-
Elmer 2400 CHNS/O analyzer. Mass spectra analyses were
performed with a VG Auto Spec instrument. The ions were
produced, FAB+ mode, with the standard Cs+ gun at ca. 30
kV, and 3-nitrobenzyl alcohol (NBA) was used as the matrix.
Syn th esis. All reactions were carried out with exclusion
of air using standard Schlenk techniques. Solvents were dried
by known procedures and distilled under argon prior to use.
The complex Os(η5-C5H5)Cl(PiPr3)2 (1) was prepared according
to the literature method.6
P r ep a r a tion of Os(η5-C5H5)Cl{η2-HCtC-C(OH)P h 2}-
(P iP r 3) (2). A suspension of Os(η5-C5H5)Cl(PiPr3)2 (1) (200 mg,
0.33 mmol) in 10 mL of pentane was treated with 81.8 mg (0.39
mmol) of 1,1-diphenyl-2-propyn-1-ol. After the mixture was
stirred for 30 min at room temperature, a violet solid was
formed, which was separated by decantation, washed with
pentane, and dried in vacuo. Yield: 170 mg (80%). IR
Con clu d in g Rem a r k s
This study has revealed that the lability of an Os-P
bond of Os(η5-C5H5)Cl(PiPr3)2 also allows the prepara-
tion of the allenylidene compound Os(η5-C5H5)Cl-
(dCdCdCPh2)(PiPr3) containing the unusual Os(η5-
C5H5) unit. This complex is obtained via the isolable
intermediate
Os(η5-C5H5)Cl{η2-HCtC-C(OH)Ph2}-
(PiPr3) and has a very remarkable nucleophlic character.
As a result of its high nucleophilicity, which is mainly
concentrated on the Câ carbon atom of the diphenylal-
lenylidene ligand, marked differences in reactivity are
observed between this allenylidene complex and those
stabilized by cationic ruthenium and osmium fragments.
Previous EHT-MO calculations8v,10,17,18 indicate that the
allenylidenes are π-acceptor groups and that the HOMO
of this type of complexes is mainly located on the Câ
carbon atom of the allenylidene. Thus, the differences
in reactivity seem to be not only a consequence of the
neutral charge of the Os(η5-C5H5)Cl(PiPr3) fragment but
also a result of the high basicity of the phosphine, the
large π-donor power of the chlorine, and the intrinsically
higher basicity of the osmium atom in comparison with
ruthenium.32
(Nujol): ν(OH) 3353-3337 cm-1, ν(CtC) 1801 cm-1
.
1H NMR
(300 MHz, C6D6, 293 K): δ 7.98 (d, 3J (HH) ) 7.5 Hz, 4 H, o-Ph),
3
3
7.23 (dd, J (HH) ) 7.5 Hz, J (HH) ) 6.9 Hz, 4 H, m-Ph), 7.07
(t, 3J (HH) ) 6.9 Hz, 2 H, p-Ph), 6.93 (s, 1 H, OH), 4.83 (s, 5 H,
Cp), 4.32 (d, 3J (PH) ) 9.0 Hz, 1 H, tCH), 2.33 (m, 3 H, PCH),
The marked nucleophilic character of the allenylidene
ligand of Os(η5-C5H5)Cl(dCdCdCPh2)(PiPr3) is revealed
by the inert behavior toward alcohols, diphenylphos-
phine, benzophenone imine, pyrazole, and acetate and
in its reactions with HBF4 and dimethyl acetylenedi-
carboxylate, which afford [Os(η5-C5H5)Cl(tC-CHdCPh2)-
(PiPr3)]BF4 and Os(η5-C5H5)Cl{dCdC(CO2Me)C(CO2-
Me)dCdCPh2}(PiPr3). The latter complex, which is a
result of a novel C3 + C2 coupling reaction, involves the
insertion of the electron-withdrawing alkyne into the
CR-Câ double bond of the allenylidene ligand.
3
3
0.85 (dd, J (HH) ) 7.2 Hz, J (PH) ) 12.9 Hz, 18 H, PCCH3).
31P{1H} NMR (121.42 MHz, C6D6, 293 K): δ 10.0 (s). 13C{1H}
NMR (75.42 MHz, C6D6, 293 K, plus APT): δ 152.2, 151.7 (-,
both s, ipso-Ph), 127.9, 127.1, 126.6 (+, all s, Ph), 122.9 (+, s,
tCH), 82.2 (-, d, 2J (PC) ) 6.5 Hz, tC-), 79.9 (+, d, 2J (PC) )
1.9 Hz, Cp), 71.1 (-, s, -C(OH)), 24.1 (+, d, 1J (PC) ) 20.1 Hz,
PCH), 19.4 (+, s, PCCH3). Anal. Calcd for C29H38ClOOsP: C,
52.83; H, 5.81. Found: C, 52.61; H, 5.92. MS (FAB+): m/e
625 (M+ - Cl).
P r ep a r a tion of Os(η5-C5H5)Cl(dCdCdCP h 2)(P iP r 3) (3).
A solution of Os(η5-C5H5)Cl(PiPr3)2 (1) (200 mg, 0.33 mmol) in
10 mL of toluene was treated with 81.8 mg (0.39 mmol) of 1,1-
diphenyl-2-propyn-1-ol. The mixture was heated at 85 °C for
15 h, and a green solution was obtained. The resulting green
solution was cooled to room temperature and filtered through
Kieselguhr. The solution was concentrated to dryness, and
the addition of pentane caused the precipitation of a green
solid, which was separated by decantation, washed with
pentane, and dried in vacuo. Yield: 179 mg (85%). IR
Not only is the reactivity of the complex Os(η5-
C5H5)Cl(dCdCdCPh2)(PiPr3) limited to the nucleophilic
power of the Câ carbon atom of the allenylidene, but the
chloro ligand is also activated toward the nucleophilic
substitution, as is revealed by its reaction with KI to
give Os(η5-C5H5)I(dCdCdCPh2)(PiPr3). This property
is most probably responsible for the formation of the
pentatrienyl complex Os(η5-C5H5){(3-5-η)CH2CHCdCd
CPh2}(PiPr3), as a result of the reaction of Os(η5-
C5H5)Cl(dCdCdCPh2)(PiPr3) with CH2dCHMgBr, which
is another C3 + C2 coupling reaction. In this respect,
the complex Os(η5-C5H5)Cl(dCdCdCPh2)(PiPr3) shows
a behavior similar to that previously reported for the
complexes MCl(dCdCdCPh2)(PiPr3)2 (M ) Rh, Ir),9i
which are related to the Vaska compound and, therefore,
are also strong Lewis bases.
Finally, the synthesis of the vinylidene complex Os-
(η5-C5H5)Cl(dCdCH-CHPh2)(PiPr3) by reduction of the
Câ-Cγ double bond of the allenylidene ligand of Os(η5-
C5H5)Cl(dCdCdCPh2)(PiPr3) in the presence of NaBH4
and methanol should be pointed out. This reaction is a
new entry into the preparation of vinylidene derivatives
starting from allenylidene precursors.
(Nujol): ν(CdCdC) 1874 cm-1 1H NMR (300 MHz, CD2Cl2,
.
293 K): δ 7.80 (d, 3J (HH) ) 7.2 Hz, 4 H, o-Ph), 7.66 (t, 3J (HH)
) 7.5 Hz, 2 H, p-Ph), 7.02 (t, 3J (HH) ) 7.5 Hz, 4 H, m-Ph),
3
5.67 (s, 5 H, Cp), 2.72 (m, 3 H, PCH), 1.17 (dd, J (HH) ) 7.2
Hz, 3J (PH) ) 13.5 Hz, 9 H, PCCH3), 1.08 (dd, 3J (HH) ) 6.9
Hz, 3J (PH) ) 13.2 Hz, 9 H, PCCH3). 31P{1H} NMR (121.42
MHz, CD2Cl2, 293 K): δ 18.6 (s). 13C{1H} NMR (75.42 MHz,
2
CD2Cl2, 293 K): δ 238.5 (s, OsdCdCdC), 225.1 (d, J (PC) )
15.2 Hz, OsdCdCdC), 152.5 (s, ipso-Ph), 129.6, 127.5, 127.0
(all s, Ph), 129.1 (s, OsdCdCdC), 88.1 (s, Cp), 25.6 (d, 1J (PC)
) 29.0 Hz, PCH), 19.7, 19.5 (both s, PCCH3). Anal. Calcd for
C29H36ClOsP: C, 54.32; H, 5.65. Found: C, 54.11; H, 5.52.
MS (FAB+): m/e 643 (M+ + H).
P r ep a r a tion of [Os(η5-C5H5)Cl(tC-CHdCP h 2)(P iP r 3)]-
BF 4 (4). A solution of Os(η5-C5H5)Cl(dCdCdCPh2)(PiPr3) (3)
(52.0 mg, 0.08 mmol) in 0.5 mL of CD2Cl2 was treated with
11.0 µL (0.08 mmol) of HBF4‚OEt2. After 2 min at room
temperature, the NMR spectra showed only the presence of
the compound [Os(η5-C5H5)Cl(tC-CHdCPh2)(PiPr3)]BF4. The
green solution was then transferred to a Schlenk tube and
concentrated to dryness. The addition of diethyl ether caused
the precipitation of a green solid, which was separated by
decantation, washed with diethyl ether, and dried in vacuo.
Exp er im en ta l Section
P h ysica l Mea su r em en ts. Infrared spectra were recorded
as Nujol mulls on polyethylene sheets using a Nicolet 550
spectrometer. NMR spectra were recorded on a Varian Unity
Yield: 54.2 mg (93%). IR (Nujol): ν(BF4) 1065 cm-1
.
1H NMR
(32) Angelici, R. J . Acc. Chem. Res. 1995, 28, 51.
(300 MHz, CD2Cl2, 293 K): δ 7.66-7.42 (m, 10 H, Ph), 6.01

Study of Os(η5-C5H5)Cl(dCdCdCPh2)(PiPr3)
Organometallics, Vol. 17, No. 16, 1998 3485
Ta ble 2. Cr ysta l Da ta a n d Da ta Collection a n d
(s, 1 H, dCH), 5.94 (s, 5 H, Cp), 2.61 (m, 3 H, PCH), 1.26 (dd,
3J (HH) ) 7.2 Hz, 3J (PH) ) 15.0 Hz, 9 H, PCCH3), 1.21 (dd,
3J (HH) ) 6.9 Hz, 3J (PH) ) 15.9 Hz, 9 H, PCCH3). 31P{1H}
NMR (121.42 MHz, CD2Cl2, 293 K): δ 37.7 (s). 13C{1H} NMR
Refin em en t for Os(η5-C5H5)Cl(dCdCdCP h 2)(P iP r 3)
(3)
Crystal Data
2
(75.42 MHz, CD2Cl2, 293 K, plus APT): δ 289.1 (-, d, J (PC)
formula
molecular wt
color and habit
symmetry
space group
a, Å
C29H36ClOsP
641.20
black, prismatic block
triclinic
P1h
10.770(1)
11.323(1)
11.319(1)
77.58(1)
84.28(1)
86.78(1)
1340.5(2)
2
) 10.1 Hz, OstC), 169.1 (-, s, -CHdC), 138.2, 137.5 (-, both
s, ipso-Ph), 135.6 (+, s, -CHdC), 133.3, 131.8, 131.6, 129.9,
129.7, 129.4 (+, all s, Ph), 94.3 (+, s, Cp), 27.8 (+, d, 1J (PC) )
29.5 Hz, PCH), 19.9 (+, s, PCCH3), 19.4 (+, d, 2J (PC) ) 2.7
Hz, PCCH3). Anal. Calcd for C29H37BF4ClOsP: C, 47.77; H,
5.11. Found: C, 47.54; H, 5.13. MS (FAB+): m/e 643 (M+).
P r ep a r a tion of Os(η5-C5H5)Cl{dC1dC2(CO2Me)C3(CO2-
Me)dC4dC5P h 2}(P iP r 3) (5). A solution of Os(η5-C5H5)Cl(d
CdCdCPh2) (3) (313 mg, 0.49 mmol) in 15 mL of toluene was
treated with dimethyl acetylenedicarboxylate (55 µL, 0.61
mmol). The mixture was heated 20 h at reflux temperature.
The brown resulting solution was evaporated to dryness, and
the residue was washed twice with 5 mL of pentane. Elution
with a mixture of ether and THF (1/1) on aluminum oxide and
further evaporation affords an orange solid. Yield: 276 mg
b, Å
c, Å
R, deg
â, deg
γ, deg
V, Å3
Z
D
calc, g cm-3
1.589
Data Collection and Refinement
diffractometer
λ(MoKR), Å; technique
monochromator
µ, mm-1
four-circle Siemens-STOE AED
0.710 73; bisecting geometry
graphite oriented
4.93
ω/2θ
3 e 2θ e 50°
253.0(2)
5505
4721 (Rint ) 0.0198)
296
(72%). IR (Nujol): ν(CdCdC) 1719 cm-1, ν(CdO) 1678 cm-1
,
ν(CdO) 1576 cm-1
.
1H NMR (300 MHz, C6D6, 293 K): δ 7.81
scan type
3
3
(d, J (HH) ) 7.7 Hz, 2 H, o-Ph), 7.72 (d, J (HH) ) 7.7 Hz, 2
H, o-Ph), 7.28 (t, 3J (HH) ) 7.7 Hz, 2 H, m-Ph), 7.16 (t, 3J (HH)
) 7.2 Hz, 2 H, m-Ph), 7.07 (t, 3J (HH) ) 7.7 Hz, 1 H, p-Ph),
2θ range, deg
temp, K
no. of data collect
no. of unique data
no. of params refined
3
7.03 (t, J (HH) ) 7.2 Hz, 1 H, p-Ph), 5.16 (s, 5 H, Cp), 3.52 (s,
3 H, CO2Me), 3.37 (s, 3 H, CO2Me), 2.65 (m, 3 H, PCH), 1.02
(dd, 3J (HH) ) 7.2 Hz, 3J (PH) ) 14.1 Hz, 9 H, PCCH3), 1.00
(dd, 3J (HH) ) 7.1 Hz, 3J (PH) ) 13.1 Hz, 9 H, PCCH3). 31P-
{1H} NMR (121.42 MHz, C6D6, 293 K): δ 21.9 (s). 13C{1H}
a
R1 [F2 > 2σ(F2)]
0.0277
0.0951
1.289
b
wR2 (all data)
Sc (all data)
2
a
b
2
NMR (75.42 MHz, C6D6, 293 K, plus APT): δ 286.6 (-, d, J -
R1(F) ) ∑||Fo| - |Fc||/∑|Fo|. wR2(F2) ) {∑[w(Fo - Fc2)2]/
∑[w(Fo2)2]}1/2
.
c Goof ) S ) {∑[w(Fo - Fc2)2]/(n - p)}1/2, where n
2
(PC) ) 12.5 Hz, C1), 215.5 (-, s, C4), 167.6 (-, s, CO2Me), 163.3
(-, s, CO2Me), 136.2 (-, s, ipso-Ph), 135.6 (-, s, ipso-Ph), 129.8,
129.7, 129.3, 128.9, 128.2 (+, all s, Ph, 1 signal masked), 114.3,
112.5, 92.7 (-, all s, C2, C3, C5), 88.9 (+, s, Cp), 52.0 (+, s,
CO2Me), 50.6 (+, s, CO2Me), 24.9 (+, d, 1J (PC) ) 29.5 Hz,
PCH), 19.8 (+, s, PCCH3), 19.0 (+, d, 2J (PC) ) 1.8 Hz, PCCH3).
Anal. Calcd for C35H42ClO4OsP: C, 53.67; H, 5.40. Found:
C, 53.58; H, 5.43. MS (FAB+): m/e 784 (M+).
is the number of reflections and p is the number of refined
parameters.
PCCH3), 11.8 (-, d, 2J (PC) ) 6.0 Hz, C5). Anal. Calcd for
C
31H39OsP: C, 58.83; H, 6.21. Found: C, 58.35; H, 5.84.
P r ep a r a tion of Os(η5-C5H5)I(dCdCdCP h 2)(P iP r 3) (7).
A solution of Os(η5-C5H5)Cl(dCdCdCPh2) (3) (250 mg, 0.39
mmol) in 15 mL of methanol was treated with potassium iodide
(70 mg, 0.42 mmol). After stirring 4 h at room temperature,
the resulting solution was evaporated to dryness. The residue
was extracted with 15 mL of dichloromethane and filtered
through Kieselguhr. The filtrate was evaporated to dryness.
The brown-orange solid was washed twice with 3 mL of
pentane and dried in vacuo. Yield: 183 mg (64%). IR
P r ep a r a t ion of Os(η5-C5H 5){(3-5-η)C5H 2C4H C3dC2d
C1P h 2}(P iP r 3) (6). A solution of Os(η5-C5H5)Cl(dCdCd
CPh2)(PiPr3) (3) (107 mg, 0.17 mmol) in 10 mL of toluene was
treated with vinylmagnesium bromide (0.17 mL, 0.17 mmol).
The mixture was stirred at room temperature for 10 min,
filtered through Kieselguhr, and concentrated to dryness. Ten
milliliters of pentane was added, and the solution was again
filtered through Kieselguhr and concentrated to dryness. The
addition of 5 mL of methanol caused the precipitation of a
yellow solid, which was separated by decantation, washed with
methanol, and dried in vacuo. Yield: 76.7 mg (73%). IR
(Nujol): ν(CdCdC) 1872 cm-1
.
1H NMR (300 MHz, C6D6, 293
3
3
K): δ 7.94 (d, J (HH) ) 7.5 Hz, 4 H, o-Ph), 7.42 (t, J (HH) )
3
7.5 Hz, 2 H, p-Ph), 6.96 (t, J (HH) ) 7.5 Hz, 4 H, m-Ph), 5.31
(s, 5 H, Cp), 2.64 (m, 3 H, PCH), 1.00 (dd, 3J (HH) ) 7.2
Hz,3J (PH) ) 13.8 Hz, 9 H, PCCH3), 0.96 (dd, 3J (HH) ) 7.2
Hz, 3J (PH) ) 13.8 Hz, 9 H, PCCH3). 31P{1H} NMR (121.42
MHz, C6D6, 293 K): δ 14.27 (s). 13C{1H} NMR (75.42 MHz,
C6D6, 293 K): δ 243.3 (s, OsdCdCdC), 234.1 (d, 2J (PC) ) 14.3
Hz, OsdCdCdC), 132.0 (s, OsdCdCdC), 129.5, 127.3, 127.0,
126.9 (all s, Ph), 86.76 (s, Cp), 27.78 (d, 1J (PC) ) 29.5 Hz,
PCH), 20.48 (s, PCCH3), 19.79 (s, PCCH3). Anal. Calcd for
(Nujol): ν(CdCdC) 1939 cm-1
.
1H NMR (300 MHz, C6D6, 293
3
3
K): δ 7.76 (d, J (HH) ) 8.4 Hz, 1 H, o-Ph), 7.75 (d, J (HH) )
3
7.8 Hz, 1 H, o-Ph), 7.53 (d, J (HH) ) 7.8 Hz, 1 H, o-Ph), 7.52
(d, 3J (HH) ) 8.1 Hz, 1 H, o-Ph), 7.25 (t, 3J (HH) ) 7.5 Hz, 2 H,
3
3
Ph), 7.13 (t, J (HH) ) 8.4 Hz, 2 H, Ph), 7.10 (t, J (HH) ) 8.2
3
Hz, 2 H, Ph), 4.61 (s, 5 H, Cp), 3.98 (ddd, J (HsynHmeso) ) 6.4
Hz, 3J (HantiHmeso) ) 7.5 Hz, 3J (PHmeso) ) 3.3 Hz, 1 H, Hmeso),
2.92 (ddd, 3J (HsynHmeso) ) 6.4 Hz, 2J (HantiHsyn) ) 2.1 Hz,
C
29H36IOsP: C, 47.54; H, 4.95. Found: C, 47.94; H, 4.99. MS
(FAB+): m/e 734 (M+).
3J (PHsyn) ) 1.5 Hz, 1 H, Hsyn), 2.01 (ddd, J (HantiHmeso) ) 7.5
3
P r ep a r a tion of Os(η5-C5H5)Cl(dCdCH-CHP h 2)(P iP r 3)
(8). A solution of Os(η5-C5H5)Cl(dCdCdCPh2)(PiPr3) (3) (135
mg, 0.210 mmol) in 10 mL of toluene was treated with 82 mg
(2.10 mmol) of NaBH4 and, after 2 min, dropwise with 1.5 mL
of methanol. After the mixture was stirred for 15 min at room
temperature, the solution was filtered through Kieselguhr. The
solvent was removed to dryness, and 16 mL of pentane was
added. The orange solution was filtered through Kieselguhr
and concentrated until a orange solid began to precipitate.
After the suspension was kept at -78 °C for 45 min, the orange
solid was separated by decantation and dried in vacuo.
Hz, 2J (HantiHsyn) ) 2.1 Hz, 3J (PHanti)) 13.5 Hz, 1 H, Hanti), 1.83
3
3
(m, 3 H, PCH), 0.85 (dd, J (HH) ) 7.2 Hz, J (PH) ) 12.5 Hz,
3
3
9 H, PCCH3), 0.84 (dd, J (HH) ) 7.2 Hz, J (PH) ) 12.9 Hz, 9
H, PCCH3). 31P{1H} NMR (121.42 MHz, C6D6, 293 K): δ 18.5
(s). 13C{1H} NMR (75.42 MHz, C6D6, 293 K, plus APT): δ
192.4 (-, d, 3J (PC) ) 3.8 Hz, C2), 142.2 (-, d, 5J (PC) ) 1.9
Hz, ipso-Ph), 142.1 (-, d, 5J (PC) ) 1.8 Hz, ipso-Ph), 129.2,
128.7, 128.3, 127.7, 125.6, 124.9 (+, all s, Ph), 103.2 (-, d,
4J (PC) ) 1.8 Hz, C1), 91.4 (-, d, J (PC) ) 11.5 Hz, C3), 74.1
2
2
2
(+, d, J (PC) ) 2.0 Hz, Cp), 33.1 (+, d, J (PC) ) 2.8 Hz, C4),
27.6 (+, d, 1J (PC) ) 26.7 Hz, PCH), 20.4, 19.9 (+, both s,
Yield: 87.8 mg (65%). IR (Nujol): ν(dCdC) 1656 cm-1
.
1H

3486 Organometallics, Vol. 17, No. 16, 1998
Crochet et al.
3
NMR (300 MHz, C6D6, 293 K): δ 7.34 (d, J (HH) ) 7.2 Hz, 1
Fourier techniques and refined by full-matrix least-squares
on F2 (SHELXL9335). Anisotropic parameters were used in
the last cycles of refinement for all non-hydrogen atoms. The
hydrogen atoms were fixed in idealized positions and refined
riding on carbon atoms with a common isotropic thermal
parameter. Atomic scattering factors, corrected for anomalous
dispersion for Os and P, were implemented by the program.
The refinement converge to R1 ) 0.0277 [F2 > 2σ(F2)] and wR2
) 0.0951 (all data), with weighting parameters x ) 0.0542 and
y ) 0.
3
H, o-Ph), 7.27 (d, J (HH) ) 7.5 Hz, 1 H, o-Ph), 7.01 (m, 8 H,
Ph), 5.24 (d, 3J (HH) ) 10.3 Hz, 1 H, dCdCH), 5.11 (s, 5 H,
Cp), 2.55 (m, 3 H, PCH), 2.38 (d, 3J (HH) ) 10.3 Hz, 1 H,
CHPh2), 0.99 (dd, 3J (HH) ) 7.2 Hz, 3J (PH) ) 13.8 Hz, 9 H,
PCCH3), 0.87 (dd, 3J (HH) ) 7.2 Hz, 3J (PH) ) 12.9 Hz, 9 H,
PCCH3). 31P{1H} NMR (121.42 MHz, C6D6, 293 K): δ 20.4
(s). 13C{1H} NMR (75.42 MHz, C6D6, 293 K, plus APT): δ
2
283.7 (-, d, J (PC) ) 13.4 Hz, OsdC), 148.6, 147.9 (-, both s,
ipso-Ph), 128.6, 128.5, 128.4 128.3 128.1 (+, all s, Ph) 126.1
(+, s, CdCH), 86.8 (+, s, Cp), 40.2 (+, s, CHPh2), 24.3 (+, d,
1J (PC) ) 29.5 Hz, PCH), 19.6, 19.3 (+, both s, PCCH3). Anal.
Calcd for C29H38ClOsP: C, 54.14; H, 5.94. Found: C, 54.59;
H, 5.85. MS (FAB+): m/e 645 (M+ + H).
Ack n ow led gm en t. We acknowledge financial sup-
port from the DGES of Spain (Project No. PB95-0806).
P.C. thanks the Ministerio de Educacio´n Cultura of
Spain for a grant.
X-r a y Str u ctu r e An a lysis of Os(η5-C5H5)Cl(dCdCd
CP h 2)(P iP r 3) (3). Crystals suitable for the X-ray diffraction
study were obtained by slow diffusion of pentane into a
concentrated solution of 3 in toluene. A summary of crystal
data and refinement parameters is reported in Table 2. The
black, prismatic crystal, of approximate dimensions 0.3 × 0.2
× 0.2 mm, was glued on a glass fiber and mounted on a
Siemens-STOE AED-2 diffractometer. A group of 48 reflec-
tions in the range 23 e 2θ e 37° were carefully centered at
253 K and used to obtain by least-squares methods the unit
cell dimensions. Three standard reflections were monitored
at periodic intervals throughout data collection: no significant
variations were observed. All data were corrected for absorp-
tion using a semiempirical method.33 The structure was solved
by Patterson (Os atom, SHELXTL-PLUS34) and conventional
Su p p or tin g In for m a tion Ava ila ble: Tables of atomic
coordinates and equivalent isotropic displacement coefficients,
anisotropic thermal parameters, experimental details of the
X-ray study, and bond distances and angles for 3 (11 pages).
Ordering information is given on any current masthead page.
OM9802109
(33) North, A. C. T.; Phillips, D. C.; Mathews, F. S. Acta Crystallogr.
1968, A24, 351.
(34) Sheldrick, G. SHELXTL-PLUS; Siemens Analitical X-ray In-
struments Inc., Madison WI, 1990.
(35) Sheldrick, G. SHELXL-93, Program for Crystal Structure
Refinement; Institu¨t fu¨r Anorganische Chemie der Universita¨t, Go¨t-
tingen, Germany, 1993.