The Os(CO)(PiPr3)2 unit as a support for the transformation of two alkyne molecules into new organometallic ligands

Article abstract of DOI:10.1021/om970301q

In 2-propanol, the C-C triple bond of one of the two alkynyl ligands of the complex Os-(C₂Ph)₂(CO)(PⁱPr₃)₂ (1) can be broken by water to give Os(CH₂Ph)(C₂Ph)(CO)₂(PⁱPr ₃)₂ (2). The reaction involves a metal-promoted, hydration-disproportionation of the transformed alkynyl ligand catalyzed by the solvent. Thus, the treatment of 1 with H₂¹⁸O yields Os(CH₂-Ph)(C₂Ph)(C₁₈O)(CO)(PⁱPr ₃)₂ (2-¹⁸O), and the reaction of 1 with water in the presence of deuterated 2-propanol (ⁱPrOD-d₈) affords Os(CD₂Ph)(C₂Ph)(CO)₂(PⁱPr ₃)₂ (2-d₂). In methanol and in the presence of trifluoroacetic acid, complex 2 isomerizes into the osmaindene derivative Os{C(CH₂Ph)=CHC₆H₄}(CO)₂(P ⁱPr₃)₂ (3). The structure of 3 has been determined by X-ray diffraction. The geometry around the osmium atom can be described as a distorted octahedron with the two triisopropylphosphine ligands occupying two relative trans positions. The remaining perpendicular plane is formed by the carbonyl ligands mutually cis disposed and the metallacycle, which forms a planar five-membered ring with the osmium atom. In methanol-d4, complex 2 reacts with CF₃COOD to give OS{C(CH₂Ph)=CDC₆H₄}(CO)₂(P ⁱPr₃)₂ (3-d₁) and 3 in a 2.5:1 molar ratio. Complex 2 also reacts with HBF₄. The reaction leads to a mixture of 3 and the π-allyl complex [Os{η³-CH(Ph)CHCHPh}(CO)₂(PⁱPr ₃)₂]BF₄ (4), which is a result from the addition of the proton from the acid and the carbon-carbon coupling of the benzyl and alkynyl ligands of 2. Similar to 2, complex 2-d₂ reacts with HBF₄ to give a mixture of Os{C(CD₂Ph)=CHC₆H₄}(CO)₂(P ⁱPr₃)₂ (3-d₂) and [Os{η³-CD(Ph)CDCHPh}(CO)₂-(PⁱPr ₃)₂] BF₄ (4-d₂). On the basis of the isotope labeling experiments, the mechanisms of the above-mentioned transformations are discussed.

Full text of DOI:10.1021/om970301q

Organometallics 1997, 16, 3169-3177
3169
Th e Os(CO)(P iP r 3)2 Un it a s a Su p p or t for th e
Tr a n sfor m a tion of Tw o Alk yn e Molecu les in to New
Or ga n om eta llic Liga n d s
Mar´ıa L. Buil, Miguel A. Esteruelas,* Ana M. Lo´pez, and Enrique On˜ate
Departamento de Qu´ımica Inorga´nica, Instituto de Ciencia de Materiales de Arago´n,
Universidad de Zaragoza, CSIC, 50009 Zaragoza, Spain
Received April 9, 1997X
In 2-propanol, the C-C triple bond of one of the two alkynyl ligands of the complex Os-
(C2Ph)2(CO)(PiPr3)2 (1) can be broken by water to give Os(CH2Ph)(C2Ph)(CO)2(PiPr3)2 (2).
The reaction involves a metal-promoted, hydration-disproportionation of the transformed
alkynyl ligand catalyzed by the solvent. Thus, the treatment of 1 with H218O yields Os(CH2-
Ph)(C2Ph)(C18O)(CO)(PiPr3)2 (2-18O), and the reaction of 1 with water in the presence of
deuterated 2-propanol (iPrOD-d8) affords Os(CD2Ph)(C2Ph)(CO)2(PiPr3)2 (2-d 2). In methanol
and in the presence of trifluoroacetic acid, complex 2 isomerizes into the osmaindene
derivative Os{C(CH2Ph)dCHC6H4}(CO)2(PiPr3)2 (3). The structure of 3 has been determined
by X-ray diffraction. The geometry around the osmium atom can be described as a distorted
octahedron with the two triisopropylphosphine ligands occupying two relative trans positions.
The remaining perpendicular plane is formed by the carbonyl ligands mutually cis disposed
and the metallacycle, which forms a planar five-membered ring with the osmium atom. In
methanol-d4, complex 2 reacts with CF3COOD to give Os{C(CH2Ph)dCDC6H4}(CO)2(PiPr3)2
(3-d 1) and 3 in a 2.5:1 molar ratio. Complex 2 also reacts with HBF4. The reaction leads to
a mixture of 3 and the π-allyl complex [Os{η3-CH(Ph)CHCHPh}(CO)2(PiPr3)2]BF4 (4), which
is a result from the addition of the proton from the acid and the carbon-carbon coupling of
the benzyl and alkynyl ligands of 2. Similar to 2, complex 2-d 2 reacts with HBF4 to give a
mixture of Os{C(CD2Ph)dCHC6H4}(CO)2(PiPr3)2 (3-d 2) and [Os{η3-CD(Ph)CDCHPh}(CO)2-
(PiPr3)2] BF4 (4-d 2). On the basis of the isotope labeling experiments, the mechanisms of
the above-mentioned transformations are discussed.
In tr od u ction
complexes (Scheme 1),3 which should promote reactions
of C-C bond formation.
In an effort to develop new models for homogeneous
systems effective in the synthesis of functionalized
Owing to the increasing demand for the products of
organic syntheses, the developement of highly efficient
and selective synthetic methods is one of the most
urgent tasks for chemical science. In this respect, the
formation of carbon-carbon bonds mediated by transi-
ton metal compounds is significant and of general
interest.1
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1990, 112, 6232. (b) Albertin, G.; Amendola, P.; Antoniutti, S.; Ianelli,
S; Pelizz, G.; Bordignon, E. Organometallics 1991, 10, 2876. (c) J ia,
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Huang, L.; McManus, N. T.; Paglia, P.; Rettig, S. J .; White, G. S.
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G. R.; Slip, I. H. M. Organometallics 1992, 11, 3019. (f) Santos, A.;
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metallics 1993, 12, 4215. (g) Scha¨fer, M.; Mahr, N.; Wolf, J .; Werner,
H. Angew. Chem., Int. Ed. Engl. 1993, 32, 1315. (h) Barbaro, P.;
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Chim. Acta 1994, 220, 5. (i) Werner, H. J . Organomet. Chem. 1994,
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Int. Ed. Engl. 1995, 34, 191. (l) Wiedemann, R.; Wolf, J .; Werner, H.
Angew. Chem., Int. Ed. Engl. 1995, 34, 1244. (m) Bianchini, C.;
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lics 1996, 15, 272. (n) Wiedemann, R.; Steinert, P.; Gevert, O.; Werner,
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Among the group of organic molecules most frequently
studied in metal-assisted C-C bond-forming reactions,
alkynes play a prominent role, as is evident from their
participation in numerous transformations of both
fundamental and industrial relevance.2 In this area,
we have observed that if the nature (dihydrido or
dihydrogen) and the number of hydrido ligands (1, 2, 3,
or 4) of the precursors are appropiately selected, the
reactions of hydrido-osmium compounds with terminal
alkynes allow the preparation of specific organometallic
(3) (a) Werner, H.; Esteruelas, M. A.; Otto, H. Organometallics 1986,
5, 2295. (b) Andriollo, A.; Esteruelas, M. A.; Meyer, U.; Oro, L. A.;
Sa´nchez-Delgado, R. A.; Sola, E.; Valero, C.; Werner, H. J . Am. Chem.
Soc. 1989, 111, 7431. (c) Espuelas, J .; Esteruelas, M. A.; Lahoz, F. J .;
Oro, L. A.; Valero, C. Organometallics 1993, 12, 663. (d) Espuelas, J .;
Esteruelas, M. A.; Lahoz, F. J .; Oro, L. A.; Ruiz, N. J . Am. Chem. Soc.
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A.; Zeier, B. Organometallics 1994, 13, 1662. (f) Esteruelas, M. A.;
Lahoz, F. J .; On˜ate, E.; Oro, L. A.; Zeier, B. Organometallics 1994, 13,
4258. (g) Esteruelas, M. A.; Oro, L. A.; Ruiz, N. Organometallics 1994,
13, 1507. (h) Esteruelas, M. A.; Lahoz, F. J .; On˜ate, E.; Oro, L. A.;
Valero, C.; Zeier, B. J . Am. Chem. Soc. 1995, 117, 7935. (i) Esteruelas,
M. A.; Oro, L. A.; Valero, C. Organometallics 1995, 14, 3596.
X Abstract published in Advance ACS Abstracts, J une 1, 1997.
(1) (a) Stille, J . K. Chemistry of the Metal-Carbon Bond; Hartley, F.
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Chemistry; Wiley: New York, 1986. (d) Collman, J . P.; Hegedus, L. S.;
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S0276-7333(97)00301-4 CCC: $14.00 © 1997 American Chemical Society

3170 Organometallics, Vol. 16, No. 14, 1997
Buil et al.
Sch em e 1a
Sch em e 2
between the resulting fragments and the other alkyne
molecule. In agreement with Scheme 1, the bis(alkynyl)
complex Os(C2Ph)2(CO)(PiPr3)2 can be prepared accord-
ing to eq 1. As a result of the new studies in the
a
[Os]-H t OsHCl(CO)PiPr3)2 (a), OsH2Cl2(PiPr3)2 (b),
OsCl2(η2-H2)(CO)(PiPr3)2, (c), OsH3(η2-O2CCH3)(PiPr3)2 (d), and
OsH4(CO)(PiPr3)2 (e).
organic molecules from basic hydrocarbon units, we
have recently initiated a research program centered
around the transformation of these complexes affording
new C-C bonds. Thus, in order to combine C-C
coupling reactions together with C-H activation pro-
cesses, we have previously reported the reactions of the
complexes Os{(E)-CHdCHR′}Cl(CO)(PiPr3)2 (R′ ) H,
Ph) with RLi and RMgBr.4 Treatment of the alkenyl
complexes with main group organometallic compounds
leads to osmium(0) species containing olefin ligands.
These transformations involve the replacement of the
Cl- anion by the organic fragments R′ and the subse-
quent reductive carbon-carbon coupling of the η1-
carbon ligands. For butadiene and phenylbutadiene,
the osmium(0) species are stable and they do not
undergo a subsequent transformation.4a However, for
trans-stylbene and trans-methylstyrene, the metallic
center is capable of activating a C-H bond of the
substituents of the coordinated olefin to afford hydrido-
osmium(II) derivatives. The C-H activation products
depend upon the substituents present at the alkene
ligand and can be rationalized in light of the thermo-
dynamic and kinetic considerations. When the alkene
ligand is trans-methylstyrene, the activation of an ortho
carbon-carbon coupling field, we report the transfor-
mation of the above-mentioned bis(alkynyl) complex into
the derivatives Os{C(CH2Ph)dCHC6H4}(CO)2(PiPr3)2
and [Os{η3-CH(Ph)CHCHPh}(CO)2(PiPr3)2]BF4 via the
compound Os(CH2Ph)(C2Ph)(CO)2(PiPr3)2.
Resu lts a n d Discu ssion
C-C Tr ip le Bon d Clea va ge of On e of th e Tw o
Alk yn yl Liga n d s of Os(C2P h )2(CO)(P iP r 3)2. Treat-
ment of a refluxing suspension of Os(C2Ph)2(CO)(PiPr3)2
(1) in 2-propanol with water in a ca. 1:25 molar ratio
for 1 h gives a colorless solution, from which the benzyl-
dicarbonyl complex Os(CH2Ph)(C2Ph)(CO)2(PiPr3)2 (2)
was isolated as a white solid in 65% yield (Scheme 2).
The spectroscopic data obtained for complex 2 support
the proposed structure. The cis relative position of the
carbonyl ligands was inferred from the IR spectrum,
position of the phenyl ring to give OsH(C6H4CHdCH-
CH3)(CO)(PiPr3)2 is kinetically favored. OsH(C6H4-
CHdCHCH3)(CO)(PiPr3)2 evolves to the most favored
thermodynamic species, the allyl derivative OsH(η3-
CH2CHCHPh)(CO)(PiPr3)2, resulting of the C-H activa-
tion of the methyl group.4b
Our most recent interest has been centered in the
transformation of two alkyne molecules into new organic
fragments by the carbon-carbon triple bond cleavage
of one of them and subsequent carbon-carbon coupling
which shows, together with a νCtC band at 2105 cm-1
,
two strong νCO absorptions at 1988 and 1925 cm-1, a
typical pattern for mononuclear cis-dicarbonyl com-
plexes. The 13C{1H} NMR spectrum also supports this
proposal, showing two triplets at 188.01 (J C-P ) 7.2 Hz)
and 180.09 ppm (J C-P ) 8.3 Hz) attributable to the
carbonyl ligands. This spectrum also contains the
expected resonances for the alkynyl and benzyl ligands.
The Câ, CR, and CH2- carbon atoms appear at 113.41,
103.30, and 4.56 ppm as triplets with C-P coupling
constants of 2.5, 17.9, and 6.7 Hz, respectively. The CH
groups of the phosphine ligands give a virtual triplet
(4) (a) Bohanna, C.; Esteruelas, M. A.; Lahoz, F. J .; On˜ate, E; Oro,
L. A.; Sola, E. Organometallics, 1995, 14, 4825. (b) Esteruelas, M. A.;
Lahoz, F. J .; On˜ate, E.; Oro, L. A.; Sola, E. J . Am. Chem. Soc. 1996,
118, 89.

The Os(CO)(PiPr3)2 Unit as a Support
Organometallics, Vol. 16, No. 14, 1997 3171
Sch em e 3
at 25.52 ppm (N ) 25.4 Hz), which is characteristic of
two equivalent phosphine ligands in a trans relative
position. This is in agreement with the singlet at -0.78
relevant steps of the mechanism are 1-alkyne to vi-
nylidene tautomerism, conversion of the vinylidene
ligand to hydroxycarbene by intramolecular attack of
water, deprotonation of the hydroxycarbene to σ-acyl,
deinsertion of CO from the acyl ligand, and hydrocarbon
elimination by protonation of the metal-alkyl moiety.8
Bianchini’s reaction was carried out in tetrahydrofu-
ran at 60 °C. However, under the same conditions, the
formation of 2 does not take place. The transformation
of 1 into 2 was not observed in either toluene or acetone.
This suggests that during the hydration of the alkynyl
ligand of 1, the 2-propanol solvent plays a main role.
In fact, the reaction of 1 with water in 2-propanol-d8
under reflux leads to Os(CD2Ph)(C2Ph)(CO)2(PiPr3)2 (2-
d 2 in Scheme 2) in 70% yield. The presence of a CD2-
Ph group in 2-d 2 was inferred from its 2H NMR
spectrum in benzene, which shows only one broad
singlet at 2.86 Hz. In agreement with this, the 1H NMR
spectrum does not contain any resonance at 2.95 ppm.
A plausible mechanism for the formation of 2 which
allows one to rationalize the deuteration of the benzyl
group and agrees with the Bianchini’s proposal is shown
in Scheme 3. In general, the coordination of an acetyl-
ide anion to a transition metal center transfers the
nucleophilicity from the CR to Câ carbon atom.9 Thus,
the formation of 2 could initially involve the electrophilic
attack of the -OH proton from the alcohol to the Câ
carbon atom of 1. In this context, it should be noted
that the addition of electrophiles to the electron-rich Câ
of metal alkynyls has been described on many ocassions
and is the best entry to the synthesis of vinylidene
complexes.10 The alkoxide anion formed should regen-
erate 2-propanol by water deprotonation. At this stage,
the OH- anion could attack to the vinylidene ligand to
give an R-hydroxyalkenyl group. This is in agreement
with previous studies on vinylidene complexes, which
have identified the electron deficiency of the vinylidenes
at the R-carbon atom.11 The reaction of the R-hydroxy-
1
ppm found in the 31P{1H} NMR spectrum. In the H
NMR spectrum, the most noticiable resonance is a
triplet at 2.95 ppm (J H-P ) 7.3 Hz) assigned to the
CH2- protons of the benzyl group.
With H218O, the reaction product was found to be
Os(CH2Ph)(C2Ph)(C18O)(CO) (PiPr3)2 (2-18O) (Scheme 2)
by the shift of νCO from 2 (1988 and 1925 cm-1) to 2-18O
(1963 and 1890 cm-1), as a result of the change in the
reduced mass. So, the reactions shown in Scheme 2
involve a metal-promoted hydration-disproportionation
of one of the two alkynyl ligands of 1. Some related
processes have been previously described. Thus, it has
been reported that the reaction of [OsI(η6-C6H6)(dCd
CHR)(PMetBu2)]PF6 (R ) H, Me) with water gives the
carbonyl-osmium compound [OsI(η6-C6H6)(CO)(PMe-
tBu2)]PF6.5 The reaction is quite general for cationic
vinylidene complexes, which afford alkyl-carbonyl de-
rivatives in the presence of water,6 and for octahedral
complexes of ruthenium(II) and osmium(II) with one
labile halide ligand, such as cis-RuCl2(bpy)2 (bpy ) 2,2′-
bipyridine), cis-[RuCl(trpy)(bpy)]PF6 (trpy ) 2,2′,2′′-
terpyridine), and cis-OsCl2(phen)[1,2-bis(diphenylphos-
phino)benzene] (phen ) 1,10-phenanthroline), which
react with terminal alkynes and water to give the
corresponding monocarbonyl derivatives and alkane.7
Recently, Bianchini and co-workers have also observed
that the hydration of phenylacetylene in the presence
of mer,trans-RuCl2(PNP)(PPh3) leads to the cleavage of
the C-C triple bond with formation of the carbonyl
complex fac,cis-RuCl2(CO)(PNP) (PNP ) CH3CH2-
CH2N(CH2CH2PPh2)) and toluene. As a result of an
elegant mechanistic study, they propose that the most
(5) Knaup, W.; Werner, H. J . Organomet. Chem. 1991, 411, 471.
(6) (a) Bruce, M. I.; Swincer, A. G. Aust. J . Chem. 1980, 33, 1471.
(b) Bruce, M. I. Pure Appl. Chem. 1986, 58, 553. (c) Davies, S.; McNally,
J . P.; Smallridge, A. J . Adv. Organomet. Chem. 1990, 30, 30. (d)
Gamasa, M. P.; Gimeno, J .; Lastra, E.; Lanfranchi, M.; Tiripicchio, A.
J . Organomet. Chem. 1992, 430, C39.
(8) Bianchini, C; Casares, J . A.; Peruzzini, M.; Romerosa, A.;
Zanobini, F. J . Am. Chem. Soc. 1996, 118, 4585.
(7) (a) Sullivan, B. P.; Smythe, R. S.; Kober, E. M.; Meyer, T. J . J .
Am. Chem. Soc. 1982, 104, 4701. (b) Mountassier, C.; Hadda, T. B.;
Le Bozec, H. J . Organomet. Chem. 1990, 388, C13.
(9) Elschenbroich, Ch.; Salzer, A. Organometallics; VCH
Verlagsgesellschaft: Weinheim, Germany, 1989.
(10) Bruce, M. I. Chem. Rev. 1991, 91, 197.

3172 Organometallics, Vol. 16, No. 14, 1997
Buil et al.
Sch em e 4
Ta ble 1. Selected Bon d Dista n ces (Å) a n d An gles
(d eg) for Os[C(CH2P h )dCC6H4](CO)2(P iP r 3)2 (3)
Os-P(1)
Os-P(2)
Os-C(1)
Os-C(2)
Os-C(3)
Os-C(10)
O(1)-C(1)
O(2)-C(2)
2.455(1)
2.456(1)
1.932(4)
1.926(5)
2.168(4)
2.180(4)
1.163(5)
1.160(6)
C(3)-C(4)
C(3)-C(8)
C(4)-C(5)
C(5)-C(6)
C(6)-C(7)
C(7)-C(8)
C(8)-C(9)
C(9)-C(10)
C(11)-C(12)
1.417(6)
1.429(6)
1.411(7)
1.388(7)
1.417(7)
1.408(6)
1.482(6)
1.356(6)
1.530(5)
P(1)-Os-P(2)
P(1)-Os-C(1)
P(1)-Os-C(2)
P(1)-Os-C(3)
P(1)-Os-C(10)
P(2)-Os-C(1)
P(2)-Os-C(2)
P(2)-Os-C(3)
P(2)-Os-C(10)
C(1)-Os-C(2)
C(1)-Os-C(3)
C(1)-Os-C(10)
176.99(4)
91.8(2)
85.6(1)
92.3(1)
90.1(1)
88.6(2)
91.4(1)
90.8(1)
90.2(1)
98.8(2)
89.2(2)
166.6(2)
Os-C(1)-O(1)
175.7(4)
177.3(4)
114.4(3)
115.1(4)
117.8(4)
115.3(3)
124.4(3)
120.3(4)
116.8(3)
171.8(2)
94.6(2)
Os-C(2)-O(2)
Os-C(3)-C(8)
C(3)-C(8)-C(9)
C(8)-C(9)-C(10)
Os-C(10)-C(9)
Os-C(10)-C(11)
C(9)-C(10)-C(11)
C(10)-C(11)-C(12)
C(2)-Os-C(3)
C(2)-Os-C(10)
C(3)-Os-C(10)
77.5(2)
F igu r e 1. Molecular diagram of Os[C(CH2Ph)dCC6H4]-
(CO)2(PiPr3)2 (3).
Ta ble 2. Cr ysta llogr a p h ic Da ta for Com p lex
Os[C(CH2P h )dCC6H4](CO)2(P iP r 3)2 (3)
alkenyl species with a second 2-propanol molecule could
yield a hydroxycarbene intermediate. The deprotona-
tion of the hydroxycarbene group by the alkoxide anion
formed in the last step should afford an acyl complex.
Finally, the CO deinsertion could give 2 (and 2-d 2).
Alk en yl-Ben zyl Cou p lin g in t h e P r esen ce of
CF 3COOH. In methanol under reflux and in the
presence of catalytic amounts of trifluoroacetic acid, the
alkynyl benzyl complex 2 isomerizes into the osmain-
dene derivative 3 (Scheme 4), which is a result from the
C-C coupling between the benzyl and alkynyl frag-
ments of 2.
formula
mol wt
a, Å
C35H54O2OsP2 scan method
ω
758.92
34.980(4)
12.560(1)
θ (min-max), deg
1.2-25
no. of measd reflns 6227
b, Å
no. of indep reflns
6114 (Rint
0.0269)
372
)
c, Å
16.439(2)
104.171(9)
7003(1)
no. of params
no. of restraints
GOOF
â, deg
4
V, Å3
1.042
0.710 73
1.440
3.761
0.0280
0.0737
cryst syst
space group C2/c
Z
monoclinic
λ, Å
F
calcd, g cm-3
8
µ, mm-1
a
temp, °C
-100
R1
R2
a
a
SHELXL-93: R1 ) (∑||Fo| - |Fc||/∑|Fo|) calculated using 5057
observed reflections [Fo > 4σ(Fo)]. R2) ({∑w(Fo2 - Fc2)2/∑wFo
}
1/2),
4
Complex 3 was isolated as a white solid in 50% yield
w ) (1/[σ2(Fo2) + (0.0340P)2 + 14.7276P]), P ) ([Fo + 2Fc2/3])
2
1
and characterized by elemental analysis, IR and H, 31P-
calculated using all reflections.
{1H}, and 13C{1H} NMR spectroscopies, and X-ray
diffraction. A view of the molecular geometry of 3 is
shown in Figure 1. Selected bond distances and angles
are listed in Table 1.
two phosphorus atoms of the triisopropylphosphine
ligands occupying opposite positions (P(1)-Os-P(2) )
176.99(4)°). An ideal equatorial plane is formed by the
atoms C(3) and C(10) of the chelating organic ligand
coordinating with the osmium atom to form a five-
membered ring (C(3)-Os-C(10) ) 77.5(2)°) and the two
carbonyl ligands mutually cis disposed (C(1)-Os-C(2))
The coordination geometry around the osmium center
can be rationalized as a distorted octahedron with the
(11) Kostic, N. M.; Fenske, R. F. Organometallics 1982, 1, 974.

The Os(CO)(PiPr3)2 Unit as a Support
Organometallics, Vol. 16, No. 14, 1997 3173
Sch em e 5
98.8(2)°). The five-membered metallacycle is almost
planar. The deviations from the best plane are -0.0025-
(1) (Os), 0.005(5) (C(3)), -0.006 (5) (C(8)), 0.003(4) (C(9)),
and -0.001(5) (C(10)) Å. A similar situation has been
observed for the metallacycle of the complex Os(C2CO2-
Me){CHdCHC(dO)OMe}(CO)(PiPr3)2.3c In contrast to
the OsC4 ring of 3, the RhC4 rings of the compounds
Rh(η5-C5H5){C(Ph)dCHC6H4}(PiPr3)12 and Rh(η5-C5H5)-
{C4(C6F5)4}(PPh3)13 show an envelope conformation with
the rhodium atoms displaced by 0.228 and 0.239 Å,
respectively, from the plane defined by the carbon
atoms. The planarity of the OsC4 ring in 3 most
probably is a consequence of the steric hindrance
imposed by the triisopropylphosphine ligands. The Os-
C(10) distance (2.180(4) Å) is slightly longer than the
Os-C distances found in the alkenyl-osmium(II) com-
plexes Os{(E)-CHdCHPh}Cl(CO)(PiPr3)2 (1.99(1) Å),3a
[Os{CHdC(I)C(dO)OMe}(η6-C6H6)(PiPr3)]+ (2.02(1) Å),14
In methanol-d4 and in the presence of CF3COOD,
complex 2 affords Os{C(CH2PhdCDC6H4}(CO)2(PiPr3)2
(3-d 1 in Scheme 4) and 3 in a 2.5:1 molar ratio. The
presence of a deuterium atom at the Câ carbon atom of
and Os(C2CO2Me){CHdCHC(dO)OMe}(CO)(PiPr3)2
(2.103(4) Å).3c The distances C(9)-C(10) (1.356(6) Å),
C(8)-C(9) (1.482(6) Å), and C(3)-C(8) (1.429(6) Å) are
comparable to those found for the same structural
disposition of the organic ligand in Werner’s complex
2
the alkenyl unit of 3-d 1 is supported by the H NMR
spectrum of this compound, which contains only one
singlet at 6.39. The position of the deuterium atom in
3-d 1 suggests that the reaction of the formation of 3
initially proceeds by electrophilic attack of H+ at the
Câ carbon atom of the alkynyl ligand of 2 followed by
migratory insertion of the resulting vinylidine ligand
into the benzyl group (Scheme 5). The C-H activation
of the ortho-CH bond of the phenyl group located at the
Câ carbon atom of the resulting alkenyl ligand most
probably involves an Os{C(CH2Ph)dCHPh}{η1-OC(O)-
CF3}(CO)2(PiPr3)2 intermediate, which eliminates CF3-
COOH. There are precedents for this reaction. Werner
has previously reported that the alkenyl-trifluoroac-
etato complex Os(CHdCHPh){η1-OC(O)CF3}(η6-C6H6)-
(PiPr3) is relatively labile and reacts readily at room
temperarure (also in methanol) to form the related
Rh(η5-C5H5){C(Ph)dCHC6H4}(PiPr3) (1.34(1), 1.440(8),
and 1.41(1) Å, respectively).12 The Os-C(3) distance
(2.168(4) Å) is statistically identical with the Os-C bond
length found in the aryl complex OsH{C6H4CHdCHPh}-
(CO)(PiPr3)2 (2.136(7) Å)4b and agrees well with the
values previously reported for Os-C(aryl) distances
(mean 2.09(3) Å).15 The Os-P and Os-CO distances
are clearly in the range expected and deserve no further
comments.
The spectroscopy data obtained for 3 are in agreement
with the structure shown in Figure 1. According to the
mutally cis disposition of the carbonyl ligands, the IR
spectrum contains two strong νCO bands at 1970 and
1905 cm-1, and the 13C{1H} NMR spectrum shows two
metallacycle compound Os(CHdCHC6H4)(η6-C6H6)-
(PiPr3).16 The complexes M{C(Ph)dCHC6H4)(η5-C5H5)-
(PiPr3) have been similarly prepared from the alkenyl
derivatives M{C(Ph)dCHPh){η1-OC(O)CF3}(η5-C5H5)-
(PiPr3) (M ) Rh, Ir) by CF3COOH elimination.12,17
Alk en yl-Ben zyl Cou p lin g in t h e P r esen ce of
HBF 4. Complex 2 also isomerizes into 3 in the presence
of ca. 1 equivalent of HBF4. However, the yield of the
isomerization is lower than that in the presence of CF3-
COOH. Thus, treatment of 2 with HBF4 leads to a
triplets at 189.76 (J C-P ) 8.1 Hz) and 188.41 (J C-P
)
8.7 Hz) ppm. Furthermore, this spectrum exhibits a
triplet at 166.44 ppm, with a C-P coupling constant of
10.4 Hz, corresponding to the aromatic carbon atom
bonded to the osmium. The rest of the carbon atoms of
the phenyl rings give singlets between 145.34 and
120.84 ppm. A singlet at 164.35 ppm and a triplet at
153.49 ppm (J C-P ) 11.1 Hz) were assigned, respec-
tively, to the Câ and CR atoms of the alkenyl moiety.
The -CH2Ph carbon atom appears as a singlet at 52.45
ppm. In the 1H NMR spectrum, the most noticiable
signals are a triplet at 6.33 ppm (J H-P ) 2.1 Hz) due to
the sCHd proton and a broad singlet at 4.15 ppm (J H-P
< 1 Hz) assigned to the -CH2Ph protons. The 31P{1H}
NMR spectrum shows a singlet at -2.89 ppm, in
agreement with the mutually trans disposition of the
triisopropylphosphine ligands.
mixture of 3 (30%) and the π-allyl complex [Os{η3-
CH(Ph)CHCHPh}(CO)2(PiPr3)2]BF4 (4), which is formed
by addition of H+ and C-C coupling of the alkenyl and
benzyl fragments of 2 according to eq 2.
(12) (a) Werner, H.; Wolf, J .; Schubert, U.; Ackermann, K. J .
Organomet. Chem. 1983, 243, C63. (b) Werner, H.; Wolf, J .; Schubert,
U.; Ackermann, K. J . Organomet. Chem. 1986, 317, 327.
(13) Gastinger, R. G.; Rausch, M. D.; Sullivan, D. A.; Palenik, G. J .
J . Organomet. Chem. 1976, 117, 355.
(14) Werner, H.; Weinand, R.; Otto, H. J . Organomet.Chem. 1986,
307, 49.
(15) Orpen, A. G.; Brammer, L.; Allen, F. H.; Kennard, O.; Watson,
D. G.; Taylor, R. J . Chem. Soc., Dalton Trans. 1989, S1.
(16) Werner, H.; Weinand, R.; Knaup, W.; Peters, K.; von Schnering,
H. G. Organometallics 1991, 10, 3967.
Complex 4 was isolated as a white solid in 55% yield
1
and characterized by elemental analysis, IR and H, 31P-
{1H}, and 13C{1H} NMR spectroscopies. As expected for
a cis-dicarbonyl compound, the IR spectrum in Nujol
(17) Werner, H.; Ho¨hn, A. J . Organomet. Chem. 1984, 272, 105.

3174 Organometallics, Vol. 16, No. 14, 1997
Buil et al.
contains two ν(CO) bands at 2020 and 1964 cm-1
.
mediate is also formed, which rearranges to the corre-
sponding η3-1-methylallylmolybdenum compound.22
The key for the above-mentioned processes is the
presence of a coordination site at the metallic center of
the alkenyl complexes, which allows the abstraction of
a hydrogen atom from the alkyl substituent, situated
at the CR carbon atom of the alkenyl group, and the
subsequent migration of the resulting hydrido ligand
to the central carbon atom of the allene. In other words,
the alkenyl-π-allyl isomerization involves a 1,2-hydro-
gen shift inside the alkenyl group.
According to Scheme 5, the isomerization of 2 to 3 in
the presence of HBF4 involves the alkenyl intermediate
Os{C(CH2Ph)dCHPh}(FBF3)(CO)2(PiPr3)2, which is
formed by direct attack of the proton from the acid to
the Câ carbon atom of the alkenyl ligand of 2 and
subsequent migratory insertion of the resulting vi-
nylidene into the metal-benzyl bond. The [BF4]- anion
is a very weak Lewis base.23 So, it is reasonable to
assume that in solution, Os{C(CH2Ph)dCHPh}(FBF3)-
(CO)2(PiPr3)2 is in equilibrium with the unsaturated
cation [Os{C(CH2Ph)dCHPh}(CO)2(PiPr3)2]+, which could
afford by a 1,2-hydrogen shift the π-allyl complex 4. If
our assumption is correct, the addition of HBF4 to
solutions of the deuterated complex 2-d 2 should afford
Furthermore, the spectrum shows the absorption due
to the [BF4]- anion with Td symmetry at about 1100
1
cm-1. The H NMR spectrum exhibits the resonances
due to the phosphine ligands and the phenyl groups,
along with a triplet (J H-H ) 11.1 Hz) of doublets (J H-P
) 7.5 Hz) at 6.14 ppm and a doublet (J H-H ) 11.1 Hz)
of doublets (J H-P ) 11.1 Hz) of doublets (J H-P ) 2.1 Hz)
at 5.11 ppm, corresponding to the meso-CH and -CHPh
protons of the allyl ligand, respectively. According to
the value of the H-H coupling constant, there is no doubt
that the meso-CH and -CHPh protons are mutually
trans disposed. The syn disposition of both phenyl rings
appears to be sterically more favored, being the usual
form adopted for this type of ligands in other com-
pounds.4b,18 In addition, it should be mentioned that
the chemical shift of the anti-CHPh protons is displaced
toward lower field with regard to that expected for anti-
CH allyl protons.19 In this context, it should be noted
that according to the structure proposed in eq 2, the
anti-CH allyl protons of 4 are in the region of a negative
shielding contribution produced by the ring current
effect of the phenyl ring. Also in agreement with the
structure proposed for 4 in eq 2, the 31P{1H} NMR
spectrum shows an AB system (δA ) 5.94 and δB ) 4.54)
with a P-P coupling constant of 185.3 Hz, which requires
a trans disposition of the phosphine ligands. The
π-coordination of the allyl ligand agrees well with the
13C{1H} NMR spectrum, which shows two singlets at
92.72 and 56.13 ppm for the central and terminal carbon
atoms, respectively.
a mixture of Os{C(CD2Ph)dCHC6H4}(CO)2(PiPr3)2 (3-
d 2) and [Os{η3-CD(Ph)CDCHPh}(CO)2(PiPr3)2]BF4 (4-
d 2). In fact, the treatment of dichloromethane solutions
of 2-d 2 with ca. 1 equiv of HBF4 leads to a mixture of
3-d 2 and 4-d 2 (eq 3) in a molar ratio similar to the 3:4
molar ratio obtained from the treatment of 2 with HBF4.
We have previously mentioned that during the reac-
tion of 2 with HBF4 to give 4, significant amounts of 3
are also formed. Accordingly, at first glance one could
think that complex 4 is a result of the isomerization
from 2 into 3 and the subsequent protonation of the
latter. However, this must be ruled out because 3 is
stable in the presence of 1 equiv of HBF4.
Previously, Werner20 has reported that the but-2-yne
compound Rh(η5-C5H5)(η2-C2Me2)(PiPr3) reacts with Brøn-
sted acids to form the 1-methylallylrhodium cation [Rh-
(η5-C5H5)(η3-CH2CHCHMe)(PiPr3)]+. The conversion of
the alkyne to the 1-methylallyl unit occurs via the
alkenyl cation [Rh(η5-C5H5){(E)-C(CH3)dCHCH3}-
(PiPr3)]+, which rearranges to give the isomeric allene-
hydrido intermediate [Rh(η5-C5H5)H(η2-CH2dCdCHMe)
(PiPr3)]+. The migration of the hydrido ligand to the
central carbon atom of the allene yields, finally, the allyl
complex. In agreement with Werner’s proposal, Schwartz
et al.21 have observed that the iridium complex trans-
Ir{(Z)-C(CH3)dCHCH3}(CO)(PPh3)2 reacts on warming
in benzene-d6 in a sealed tube to give the allyl isomer
Ir(η3-CH2CHCHMe)(CO)(PPh3)2 and in the reaction of
Mo(η5-C5H5)(η2-C2Me2)LL′]BF4 (L ) L′ ) P(OMe)3; L )
CO, L′ ) PEt3) with hydrido donors an alkenyl inter-
The positions of the deuterium atoms in 3-d 2 and 4-d 2
2
are supported by the corresponding H NMR spectra.
2
The H NMR spectrum of 3-d 2 shows only one singlet
at 4.31 ppm, whereas the 2H NMR spectrum of 4-d 2
contains two broad singlets at 6.16 and 5.17 ppm. A
possible mechanism for the formation of 3-d 2 and 4-d 2
which accounts for the deuterium distribution in these
compounds is shown in Scheme 6. The lower coordina-
tion power of the [BF4]- anion compared to that of the
[CF3COO]- can explain why HBF4 produces not only
the isomerization of 2 into 3 but also the formation of
4.
(18) (a) Tulip, T. H.; Ibers, J . A. J . Am. Chem. Soc. 1979, 101, 4201.
(b) Murall, N. W.; Welch, A. J . J . Organomet. Chem. 1986, 301, 109.
(c) Cotton, F. A.; Luck, R. L. Acta Crystallogr., Sect. C Cryst. Struct.
Commun. 1990, 46, 138. (d) Faller, J . W.; Lambert, C.; Mazzieri, M.
R. J . Organomet. Chem. 1990, 383, 161. (e) Henly, T. J .; Wilson, S. R.;
Shapley, J . R. Inorg. Chem. 1988, 27, 2551.
Con clu d in g Rem a r k s
This study has revealed that in 2-propanol, the C-C
triple bond of one of the two alkynyl ligands of complex
(19) Lobach, M. I.; Babitskii, B. D.; Kormer, V. A. Russ. Chem. Rev.
(Engl. Transl.) 1967, 36, 477.
(20) Wolf, J .; Werner, H. Organometallics 1987, 6, 1164.
(21) Schwartz, J .; Hart, D. W.; McGiffert, B. J . Am. Chem. Soc. 1974,
96, 5613.
(22) Allen, S. R.; Baker, P. K.; Barnes, S. G.; Bottrill, M.; Green,
M.; Orpen, A. G.; Williams, I. D. J . Chem. Soc., Dalton Trans. 1983,
927.
(23) Beck, W.; Su¨nkel, K. Chem. Rev. 1988, 88, 1405.

The Os(CO)(PiPr3)2 Unit as a Support
Organometallics, Vol. 16, No. 14, 1997 3175
Sch em e 6
Os(C2Ph)2(CO)(PiPr3)2 (1) can be selectively broken by
reaction with water to afford Os(C2Ph)(CH2Ph)(CO)2-
(PiPr3)2 (2). The reaction involves a metal-promoted
hydration-disproportionation of the transformed alkynyl
ligand catalyzed by the solvent.
Exp er im en ta l Section
Gen er a l Con sid er a tion s. All reactions were carried out
under an argon atmosphere by using Schlenk techniques.
Solvents were dried and purified by known procedures and
distilled under argon prior to use. The starting complex Os-
(C2Ph)2(CO)(PiPr3)2 (1) was prepared by a published method.24
P h ysica l Mea su r em en ts. NMR spectra were recorded on
a Varian Unity 300 or on a Bruker ARX 300 spectrometer at
room temperature unless stated. Chemical shifts are expresed
in parts per million, upfield from Si(CH3)4 (1H, 13C{1H}) and
85% H3PO4 (31P{1H}). Coupling constants J and N (N ) J (HP)
+ J (HP′) for 1H and N ) J (CP) + J (CP′) for 13C) are given in
Hertz. Infrared spectra were recorded on a Nicolet 550
spectrometer using Nujol mulls on polyethylene sheets. C and
H analyses were carried out on a Perkin Elmer 240C mi-
croanalyzer.
In methanol, the trifluoroacetic acid catalyzes the
isomerization of complex 2 into Os{C(CH2Ph)dCHC6-
H4}(CO)2(PiPr3)2 (3), which contains an ortho-metalated
phenyl group. According to the results from isotope
labeling experiments, the isomerization involves the
initial attack of the proton from the acid to the Câ carbon
atom of the alkynyl ligand of the starting compound.
The subsequent migratory insertion of the resulting
vinylidene into the metal-benzyl bond gives an alkenyl
intermediate containing a coordinated trifluoroacetato
anion, which evolves into 3 by trifluroacetic acid elimi-
nation. In the presence of tetrafluoroboric acid, complex
2 also isomerizes into 3 but, furthermore, it produces
the π-allyl derivative [Os{η3-CH(Ph)CHCHPh}(CO)2-
(PiPr3)2]BF4 (4), which is a result from the addition of
the proton from the acid and the carbon-carbon cou-
pling of the benzyl and alkynyl fragments of 2. In this
case the isotope labeling experiments suggest that the
formation of 4 involves the unsaturated alkenyl inter-
mediate [Os{C(CH2Ph)dCHPh}(CO)2(PiPr3)2]+, which
by a 1,2-hydrogen shift evolves into 4. The different
behavior of 2 toward trifluoroacetic acid and tetrafluo-
roboric acid can be rationalized in terms of different
coordination powers of the corresponding anions. The
trifluoroacetato, which has a stronger coordination
power than the tetrafluoroborato, prevents the forma-
tion of the unsaturated alkenyl intermediate [Os{C(CH2-
Ph)dCHPh}(CO)2(PiPr3)2]+, which is the key for the
formation 4. Thus, complex 3 is the only species formed
from 2, in the presence of this acid.
Reaction of Os(C2P h )2(CO)(P iP r 3)2 (1) with H2O: pr epa-
r a tion of Os(C2P h ) (CH2P h )(CO)2(P iP r 3)2 (2). A stirred
suspension of Os(C2Ph)2(CO)(PiPr3)2 (1) (165 mg, 0.22 mmol)
in 6 mL of 2-propanol was treated with water (10 µL, 0.55
mmol). The mixture was stirred for 60 min at reflux temper-
ature. The resulting yellow solution was cooled, and a white
solid precipitated. The solution was decanted, and the white
solid was washed with methanol and dried in vacuo. Yield:
110 mg (65%). Anal. Calcd For C35H54O2OsP2: C, 55.39; H,
7.17. Found: C, 55.12; H, 7.03.
IR (Nujol, cm-1): ν(C≡C) 2105 (s); ν(CO) 1988, 1925(s);
ν(C6H5) 1596 cm-1 1H NMR (300 MHz, C6D6): δ 7.53 (d, 2H,
.
J H-H ) 7.8 Hz), 7.51 (d, 2H, J H-H ) 7.8 Hz), 7.26 (t, 2H, J H-H
) J H-H′ ) 7.8 Hz), 7.19 (t, 2H, J H-H ) J H-H′ ) 7.8 Hz), 6.99
(m, 2H) [C6H5 and C-C6H5], 2.95 (t, 2H, J H-P ) 7.3 Hz, -CH2);
2.60 (m, 6H, PCH), 1.37 and 1.09 (both dvt, 18H, J H-H ) 6.9
Hz, N ) 13.8 Hz, PCCH3). 31P{1H} NMR (121.4 MHz, C6D6):
δ -0.78 (s). 13C{1H} NMR (75.43 MHz, C6D6): δ 188.01 (t,
J C-P ) 7.2 Hz, CO), 180.09 (t, J C-P ) 8.3 Hz, CO), 155.19 (t,
J C-P ) 1.2 Hz, Cipso), 129.67 (t, J C-P ) 1.8 Hz, Cipso), 130.76 (t,
J C-P ) 1.4 Hz), 129.98 (s), 128.42 (s), 125.2 (s), 122.56 (s), [C6H5
and C-C6H5), 113.41 (t, J C-P ) 2.5 Hz, ≡Câ), 103.30 (t, J C-P
) 17.9 Hz, Co≡), 25.52(vt, N ) 25.4 Hz, PCH), 20.37 (s,
PCCH3), 19.28 (s, PCCH3), 4.56 (t, J C-P ) 6.7 Hz, CH2).
Reaction of Os(C2P h )2(CO)(P iP r 3)2 (1) with H218O P r epa-
r a tion of Os(C2P h )(CH2P h )(C18O)(CO)(P iP r 3)2 (2-18O). A
stirred suspension of Os(C2Ph)2(CO)(PiPr3)2 (1) (344 mg, 0.46
In conclusion, we prove that the Os(CO)(PiPr3)2 unit
permits not only the introduction, in a sequential
manner, of two alkyne molecules into the metallic center
(eq 1), but also the selective transformation of one of
them (Scheme 2) and the C-C coupling of the η1-carbon
ligands of the resulting complex to afford new organic
fragments (Scheme 4, eq 2).
(24) Werner, H.; Meyer, U.; Esteruelas, M. A.; Sola, E.; Oro, L. A.
J . Organomet. Chem. 1989, 366, 187.

3176 Organometallics, Vol. 16, No. 14, 1997
Buil et al.
mmol) in 6 mL of 2-propanol was treated with H218O (55 µL,
3.05 mmol). The mixture was stirred for 2 h at reflux
temperature. The resulting yellow solution was cooled, and a
white solid precipitated. The solution was decanted, and the
white solid was washed with methanol and dried in vacuo.
Yield: 228 mg (65%).
IR (Nujol, cm-1): ν(C≡C) 2105 (s); ν(CO) 1963, 1890 (s);
ν(C6H5) 1596 cm-1.1H NMR (300 MHz, C6D6): δ 7.53 (d, 2H,
J H-H ) 7.8 Hz), 7.51 (d, 2H, J H-H ) 7.8 Hz), 7.26 (t, 2H, J H-H
) J H-H′ ) 7.8 Hz), 7.19 (t, 2H, J H-H ) J H-H′ ) 7.8 Hz), 6.99
(m, 2H) [C6H5 and C-C6H5], 2.95 (t, J H-P ) 7.3 Hz, 2H, Os-
CH2), 2.60 (m, 6H, PCH), 1.37 and 1.09 (both dvt, 18H, J H-H
) 6.9 Hz, N ) 13.8 Hz, PCCH3). 31P{1H}NMR (121.4 MHz,
C6D6): δ -0.78 (s).
R ea ct ion of Os(C2P h )2(CO)(P iP r 3)2 (1) w it h H2O in
2-P r op a n ol-d 8: P r ep a r a tion of Os(C2P h )(CD2P h )(CO)2-
(P iP r 3)2 (2-d 2). A stirred suspension of Os(C2Ph)2(CO)(PiPr3)2
(1) (260 mg, 0.35 mmol) in 2 mL of 2-propanol-d8 was treated
with H2O (16 µL, 0.87 mmol). The mixture was stirred for 60
min at reflux temperature. The resulting yellow solution was
cooled, and a white solid precipitated. The solution was
decanted, and the white solid was washed with methanol and
dried in vacuo. Yield: 186 mg (70%).
R ea ct ion of Os(C2P h )(CH2P h )(CO)2(P iP r 3)2 (2) w it h
HBF 4: P r ep a r a tion of [Os{η3-CH(P h )CHCHP h }(CO)2-
(P iP r 3)2]BF 4 (4). A solution of Os(C2Ph)(CH2Ph)(CO)2 (PiPr3)2
(2) (237 mg, 0.31 mmol) in 6 mL of dicloromethane was treated
with HBF4 (43 µL, 0.31 mmol). Immediately a yellow solution
was observed. The mixture was stirred for 20 min. The
solution was concentrated to ca. 0.5 mL, and after the addition
of diethyl ether, a white solid and a yellow solution were
obtained. The solution was decanted, and the white solid was
washed with diethyl ether and dried in vacuo. The white solid
was characterized as [Os(η3-CH(Ph)CHCHPh)(CO)2(PiPr3)2]-
BF4 (4). Yield: 145 mg (55%). The yellow solution was
concentrated to dryness, and the residue was treated with 4
mL of methanol to yield a white solid which was washed with
methanol and dried in vacuo. The product was characterized
1
as 3 by H and 31P{1H} NMR. Yield: 71 mg (30%).
Data for 4: Anal. Calcd for C35H55BF4O2OsP2: C, 49.64; H,
6.55. Found: C, 50.18; H, 6.65. IR (Nujol, cm-1): ν(CO) 2020,
1964(s). 1H NMR (300 MHz, CDCl3): δ 7.60 (d, 4H, J H-H
)
6.9 Hz, o-C6H5), 7.39 (t, 4H, J H-H ) 7.2 Hz, m-C6H5), 7.32 (d,
2H, J H-H ) 7.2 Hz, p-C6H5), 6.14 (td, 1H, J H-H ) 11.1 Hz, J H-P
) 7.5 Hz, allyl-CHmeso), 5.11 (ddd, 2H, J H-H ) J H-P ) 11.1
Hz, J H-P ) 2.1 Hz, allyl-CHPh), 2.84 (m, 3H, PCH), 2.13 (m,
3H, PCH), 1.55 (dd, 18 H, J H-H ) 6.9 Hz, J H-P ) 13.5 Hz,
PCCH3), 0.81 (dd, 18H, J H-H ) 7.2 Hz, J H-P ) 14.4 Hz,
PCCH3). 31P{1H} NMR (121.4 MHz, CD2Cl2): AB system δA)
5.94, δB) 4.54, J AB) 185.3 Hz. 13C{1H} NMR (75.43 MHz,
CDCl3): δ 183.33 (t, J C-P ) 9.8 Hz, CO), 137.27 (s, Cipso-
Ph), 130.29 (s, CHortho-Ph), 129.18 (s, CHmeta-Ph), 128.36
(s, CHpara-Ph), 96.72 (s, allyl-CHmeso), 56.13 (s, allyl-
CHPh), 26.97 (d, J C-P ) 24.1 Hz, PCH), 26.63 (d, J C-P ) 20.7
Hz, PCH), 19.96 (s, PCCH3), 19.00 (s, PCCH3).
IR (Nujol, cm-1): ν(C≡C) 2105(s); ν(CO) 1988, 1925(s);
ν(C6H5) 1596. 1H NMR (300 MHz, C6D6): δ 7.53 (d, 2H, J H-H
) 7.8 Hz), 7.51 (d, 2H, J H-H ) 7.8 Hz), 7.26 (t, 2H, J H-H
)
J H-H′ ) 7.8 Hz), 7.19 (t, 2H, J H-H ) J H-H′ ) 7.8 Hz), 6.99 (m,
2H) [C6H5 and C-C6H5]; 2.60 (m, 6H, PCH), 1.37 and 1.09
(both dvt, 18H, J H-H ) 6.9 Hz, N) 13.8 Hz, PCCH3). 31P{1H}
NMR (121.4 MHz, C6D6): δ -0.78 (s). 2H NMR (C6H6): δ 2.86
(br, -CD2).
Isom er iza tion of Os(C2P h )(CH2P h )(CO)2(P iP r 3)2 (2) in
Rea ction of Os(C2P h )(CD2P h )(CO)2(P iP r 3)2 (2-d 2) w ith
HBF 4: P r ep a r a tion of [Os{η3-CD(P h )CDCHP h }(CO)2-
th e P r esen ce of CF 3COOH: P r ep a r a tion of Os{C(CH2-
(P iP r 3)2]BF 4 (4-d 2) a n d Os{C(CD2P h )dCH C6H 4} (CO)2-
(P iP r 3)2 (3-d 2). A solution of Os(C2Ph)(CD2Ph)(CO)2(PiPr3)2
(2-d 2) (190 mg, 0.25 mmol) in 6 mL of dicloromethane was
treated with HBF4 (34 µL, 0.25 mmol). Inmediately a yellow
solution was observed. The mixture was stirred for 40 min.
The solution was concentrated to ca. 0.5 mL, and after the
addition of diethyl ether, a white solid and a yellow solution
were obtained. The solution was decanted, and the white solid
was washed with diethyl ether and dried in vacuo. The white
solid was characterized as [Os{η3-CD(Ph)CDCHPh}(CO)2-
(PiPr3)2]BF4 (4-d 2). Yield: 116mg (55%). The yellow solution
was concentrated to dryness, and the residue was treated with
4 mL of methanol to yield a white solid which was washed
with methanol, and dried in vacuo. The solid was character-
ized as Os{C(CD2Ph)dCHC6H4}(CO)2(PiPr3)2 (3-d 2). Yield: 71
mg (30%).
Spectroscopy data for 4-d 2: 1H NMR (300 MHz, CDCl3) δ
7.60 (d, 4H, J H-H ) 6.9 Hz, o-C6H5), 7.39 (t, 4H, J H-H ) 7.2
Hz, m-C6H5), 7.32 (d, 2H, J H-H ) 7.2 Hz, p-C6H5), 5.11 (dd,
1H, J H-P ) 11.1 Hz, J H-P ) 2.1 Hz, allyl-CHPh), 2.85 (m, 3H,
PCH), 2.14 (m, 3H, PCH), 1.55 (dd, 18H, J H-H ) 6.9 Hz, J H-P
) 13.5 Hz, PCCH3), 0.81 (dd, 18H, J H-H ) 7.2 Hz, J H-P ) 14.4
Hz, PCCH3). 31P{1H} NMR (121.4 MHz, CD2Cl2): AB system
δA ) 5.94, δB ) 4.54, J AB ) 185.3 Hz. 2H NMR (CH2Cl2): δ
6.16 (br, allyl-CDmeso), 5.17 (br, allyl-CDPh).
P h )dCHC6H4}(CO)2(P iP r 3)2 (3). To a stirred suspension of
Os(C2Ph)(CH2Ph)(CO)2(PiPr3)2 (2) (200 mg, 0.26 mmol) in 5 mL
of methanol was added CF3COOH (5 µL, 0.06 mmol). The
mixture was stirred for 16 h at reflux temperature. A white
solid was formed. The solution was decanted, and the white
solid was washed with methanol and dried in vacuo. Yield:
100 mg (50%). Anal. Calcd for C35H54O2OsP2: C, 55.38; H,
7.17. Found: C, 54.81; H, 7.11.
IR (Nujol, cm-1): ν(CO) 1970, 1905(s). 1H NMR (300 MHz,
CD2Cl2): δ 7.82 (d, 1H, J H-H ) 6.9 Hz, C6H4), 7.34-7.09 (m,
5H, Ph), 6.75-6.5 (m, 3H, C6H4), 6.33 (t, 1H, J H-H ) 2.1 Hz,
dCH), 4.15 (br, 2H, CH2Ph), 2.53 (m, 6H, PCH); 1.25 and 1.05
(both dvt, 18H, J H-H ) 7.5 Hz, N ) 13.5 Hz, PCCH3).
31P{1H}NMR (121.4 MHz, CD2Cl2): δ -2.89 (s). 13C{1H} NMR
(75.43 MHz, CD2Cl2): δ 189.76 (t, J C-P ) 8.1 Hz, CO), 188.41
(t, J C-P ) 8.7 Hz, CO), 166.44 (t, J C-P ) 10.4 Hz, OsC), 164.35
(s, )C), 153.49 (t, J C-P )11.1 Hz, OsCd); 145.34, 143.99,
143.80, 129.98, 128.40, 125.54, 123.07, 121.90, 120.84 (all s,
C6H4 and Ph), 52.45 (s, CH2), 26.59 (vt, N ) 23.6 Hz, PCH),
20.19 (s, PCCH3), 19.28 (s, PCCH3).
Isom er iza tion of Os(C2P h )(CH2P h )(CO)2(P iP r 3)2 (2) in
th e P r esen ce of CF 3COOD: P r ep a r a tion of Os{C(CH2-
P h )dCDC6H4}(CO)2(P iP r 3)2 (3-d 1). To a stirred suspension
of Os(C2Ph)(CH2Ph)(CO)2(PiPr3)2 (2) (150 mg, 0.198 mmol) in
5 mL of methanol-d4 was added CF3COOD (8 µL, 0.1 mmol).
Spectroscopy data for 3-d 2: 1H NMR (300 MHz, CD2Cl2) δ
7.82 (d, 1H, J H-H ) 6.9 Hz, C6H4), 7.34-7.09 (m, 5H, Ph),
6.75-6.5 (m, 3H, C6H4), 6.33 (t, 1H, J H-H ) 2.1 Hz, )CH),
2.53 (m, 6H, PCH), 1.25 and 1.05 (both dvt, 18H, J H-H ) 7.5
Hz, N ) 13.5 Hz, PCCH3). 31P{1H} NMR (121.4 MHz, CD2-
Cl2): δ -2.89 (s). 2H NMR (CH2Cl2): δ 4.31 (br, CD2Ph).
The mixture was stirred for 24 h at reflux temperature.
A
white solid was formed. The solution was decanted, and the
white solid was washed with methanol-d4 and dried in vacuo.
Yield: 75 mg (50%). The solid was indentified by 1H NMR
spectroscopy as a mixture of 3-d 1 and 3 in a 2.5:1 molar ratio.
Spectroscopy data for 3-d 1:1H NMR (300 MHz, CD2Cl2) δ 7.82
(d, 1H, J H-H ) 6.9 Hz, C6H4), 7.34-7.09 (m, 5H, Ph), 6.75-
6.5 (m, 3H, C6H4), 4.15 (br, 2H, CH2Ph), 2.53 (m, 6H, PCH),
1.25 and 1.05 (both dvt, 18H, J H-H ) 7.5 Hz, N ) 13.5 Hz,
Cr ysta l Da ta for Os[C(CH2P h )CdCHC6H4](CO)2(P iP r 3)2
(3). Crystals suitable for the X-ray diffraction study were
obtained from a saturated solution of 3 in acetone at -20 °C.
A yellow crystalline prism of approximate dimensions 0.64 ×
0.30 × 0.28 mm was glued onto the tip of a glass fiber. A set
of randomly searched reflections were indexed to monoclinic
2
PCCH3). 31P{1H} NMR (121.4 MHz, CD2Cl2): δ -2.89 (s). H
NMR (CH2Cl2): δ 6.39 (br, dCD).

The Os(CO)(PiPr3)2 Unit as a Support
Organometallics, Vol. 16, No. 14, 1997 3177
symmetry and accurate unit cell dimensions determined by
least-squares refinement of 25 carefully centred reflections (25
e 2θ e 30°). Data were collected on a Siemens P4 diffracto-
meter with graphite-monochromated Mo KR radiation by the
ω scan method. Three orientation and intensity standards
were monitored every 100 reflections throughout data collec-
tion; no significant variation was observed. Data were cor-
rected for absorption using a numerical method (Face-
Indexed). The structure was solved by Patterson and
conventional Fourier techniques and refined by full-matrix by
least-squares on F2 (SHELXL-93).25 The two methyl groups
of an isopropyl substituent were observed disordered (atoms
C44a, C45a, C44b, and C45b). These groups were refined with
two moieties with complementary occupancy factors (0.41(2)
a-labeled and 0.59(2) b-labeled atoms) and restrained geom-
etry. All non-hydrogen atoms were refined anisotropic, and
all hydrogens, except those of the disordered group, were fixed
in idealized positions. The largest peak and hole in the final
difference map were 1.25 and -0.78 e Å-3
.
Ack n ow led gm en t. We thank the DGICYT (Project
No. PB95-0806, Programa de Promocio´n General del
Conocimiento) for financial support. E.O. thanks the
DGA (Diputacio´n General de Arago´n) for a grant.
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, bond distances and angles, and interatomic
distances (15 pages). Ordering information is given on any
current masthead page.
(25) Sheldrick, G. M. SHELXTL, version 5. Siemens Analytical
Automation, Inc., Analytical Instrumentation: WI, 1994.
OM970301Q