Hydride-carbyne to carbene transformation in a cyclopentadienyl-osmium complex: An alternative to the single hydride-Cα migration

Article abstract of DOI:10.1021/om011077e

Complexes OsH(η⁵-C₅H₅)(C≡CPh)(EPh₃)( PⁱPr₃) [E = Si (1), Ge (2)] react with 2.0 equiv of HBF₄·OEt₂ to give [OsH(η⁵-C₅H₅)(≡C-CH₂Ph)(P ⁱPr₃)]BF₄ (3). Treatment of 3 with KOH affords OsH(η⁵-C₅H₅)(=C=CHPh)(PⁱPr₃ ) (5) in equilibrium with the metalated species OsH(η⁵-C₅H₅)(o-C₆H₄CH =CH)(PⁱPr₃) (7) ΔH° = -3.6 ± 0.2 kcal mol^-1 and ΔS° = -10.8 ± 1.9 cal K^-1 mol ^-1 for the formation of 7). The addition of P(OMe)₃ to the solution of the isomeric mixture leads to Os(η⁵-C₅H₅){(E)-CH=CHPh}{P(OMe)₃ }(PⁱPr₃) (8), which reacts with HBF₄·OEt₂ to give [Os(η⁵-C₅H₅)(=CHCH₂Ph){P(OMe) ₃}(PⁱPr₃)]BF₄ (4).

Full text of DOI:10.1021/om011077e

2332
Organometallics 2002, 21, 2332-2335
Notes
Hyd r id e-Ca r byn e to Ca r ben e Tr a n sfor m a tion in a
Cyclop en ta d ien yl-Osm iu m Com p lex: An Alter n a tive to
th e Sin gle Hyd r id e-Cr Migr a tion
Miguel Baya and Miguel A. Esteruelas*
Departamento de Quı´mica Inorga´nica, Instituto de Ciencia de Materiales de Arago´n,
Universidad de Zaragoza, CSIC, 50009 Zaragoza, Spain
Received December 18, 2001
Summary: Complexes OsH(η5-C5H5)(CtCPh)(EPh3)-
(PiPr3) [E ) Si (1), Ge (2)] react with 2.0 equiv of
HBF4‚OEt2 to give [OsH(η5-C5H5)(tC-CH2Ph)(PiPr3)]-
BF4 (3). Treatment of 3 with KOH affords OsH-
(η5-C5H5)(dCdCHPh)(PiPr3) (5) in equilibrium with the
the hydride-alkynyl compounds OsH(η5-C5H5)(CtCPh)-
(EPh3)(PiPr3) [E ) Si (1), Ge (2)].5 Now we have observed
that these complexes are the entry to obtain the hy-
dride-carbyne derivative [OsH(η5-C5H5)(tCCH2Ph)-
(PiPr3)]BF4 (3). The easy accesibility to 3 prompted us
to investigate the hydride-carbyne to carbene trans-
formation promoted by trimethyl phosphite, a π-acidic
ligand as carbon monoxide.
metalated species OsH(η5-C5H5)(o-C6H4CHdCH)(PiPr3)
(7) (∆H° ) -3.6 ( 0.2 kcal mol-1 and ∆S° ) -10.8 (
-1
1.9 cal K-1 mol
for the formation of 7). The addition
Complex 3 was prepared, as a dark brown solid in
nearly quantitative yield, by addition of 2.0 equiv of
HBF4‚OEt2 to diethyl ether solutions of 1 or 2 (eq 1).
The formation of FEPh3 (E ) Si, Ge) was also detected.6
When the reactions were carried out using 1.0 equiv of
HBF4‚OEt2, complex 3 was obtained in about 50% yield.
of P(OMe)3 to the solution of the isomeric mixture leads
to Os(η5-C5H5){(E)-CHdCHPh}{P(OMe)3}(PiPr3) (8),
which reacts with HBF4‚OEt2 to give [Os(η5-C5H5)-
(dCHCH2Ph){P(OMe)3}(PiPr3)]BF4 (4).
Complexes OsHCl2(tCCH2R)(PR′3)2 (PR′3 ) PiPr3,1
2
PCy3 ), isomers of the osmium counterparts to the
Grubbs-type carbene-ruthenium compounds RuCl2-
(dCHCH2R)(PR′3)2, are known and can be easily pre-
pared by reaction of the corresponding dihydride-
dichloro compounds OsH2Cl2(PR′3)2 with terminal
alkynes1,2 or alternatively with olefins.3 However, in the
solid state and in solution they do not evolve into the
carbene isomers, by migration of the hydride ligand to
the CR atom of the carbyne. DFT calculations indicate
that, although the isomer energies are similar, the
necessary energy for the hydride migration is too large
(27.2 kcal mol-1).3
Despite this high energy barrier and despite the
saturated character of the carbyne compounds, complex
OsHCl2(tCEt)(PiPr3)2 reacts with carbon monoxide to
give the carbene derivative OsCl2(dCHEt)(CO)(PiPr3)2,
at convenient rate.3,4 To rationalize this surprising
finding, it has been proposed that the mechanism of the
above-mentioned transformation must involve nucleo-
philic assistance of the hydride-to-carbyne-carbon mi-
gration; Os-L bond making will lower the activation
energy from its unimolecular value.3
The formation of a hydride-carbyne species according
to eq 1 is strongly supported by the 1H and 13C{1H}
NMR spectra of the obtained solid. The 1H NMR
spectrum in chloroform-d contains at -12.15 a doublet
(2J HP ) 24 Hz), due to the hydride ligand, whereas in
the 13C{1H} NMR spectrum the CR resonance of the
carbyne is observed at 290.9 ppm.
Complex 3 is stable in chloroform-d under argon, and
the migration of the hydride to the CR atom of the
carbyne is not observed. The addition of trimethyl
phosphite to chloroform-d solutions of 3 gives a complex
mixture of products, which does not contain the carbene
derivative [Os(η5-C5H5)(dCHCH2Ph){P(OMe)3}(PiPr3)]-
BF4 (4). This complex can be obtained according to
Scheme 1.
In the context of our investigations on the reactivity
of the cyclopentadienyl-osmium complex Os(η5-C5H5)Cl-
(PiPr3)2, we have recently reported the preparation of
The CH2 group of the carbyne ligand of 3 is fairly
acidic and can be easily deprotonated. Thus, the
(1) Espuelas, J .; Esteruelas, M. A.; Lahoz, F. J .; Oro, L. A.; Ruiz, N.
J . Am. Chem. Soc. 1993, 115, 4683.
(2) Werner, H.; J ung, S.; Weberndo¨rfer, B.; Wolf, J . Eur. J . Inorg.
Chem. 1999, 951.
(3) Spivak, G. J .; Coalter, J . N.; Oliva´n, M.; Eisenstein, O.; Caulton,
K. G. Organometallics 1998, 17, 999.
(4) Spivak, G. J .; Caulton, K. G. Organometallics 1998, 17, 5260.
(5) Baya, M.; Esteruelas, M. A.; On˜ate, E. Organometallics 2001,
20, 4875.
(6) (a) MS (FAB+) of F-GePh3: m/z 305 (Ge-Ph3+), 247 (F-
GePh2+)]. (b) 13C{1H} NMR spectrum of FSiPh3 (75.4 MHz, C6D6, plus
3
2
APT): ∆ 135.8 (+, d, Cortho Ph, J CF ) 1.9); 133.4 (-, d, Cipso Ph, J CF
) 17.1); 131.4 (+, s, Cpara Ph); 128.8 (+, s, Cmeta Ph)].
10.1021/om011077e CCC: $22.00 © 2002 American Chemical Society
Publication on Web 05/02/2002

Notes
Organometallics, Vol. 21, No. 11, 2002 2333
Sch em e 1
treatment of methanol solutions of 3 with 5.5 equiv of
KOH affords the hydride-vinylidene OsH(η5-C5H5)-
(dCdCHPh)(PiPr3) (5) in equilibrium with its metalated
of the aryl group. Intermediate 6b is in equilibrium with
its E-isomer 6a . The formation of 6a and 6b could be
the result of the migration in 5 of the hydride to the CR
atom of the vinylidene, which should be rotating around
the osmium-vinylidene axis. Alternatively, the equi-
librium 6a -6b could be a consequence of the isomer-
ization of 6b into 6a via a zwitterionic carbene form.
The presence, in spectroscopically undetected amounts,
of 6a in the isomeric mixture is strongly supported by
the reaction of the latter with trimethyl phosphite. The
addition of 2.0 equiv of this ligand to the isomeric
mixture in toluene affords the E-styryl derivative Os-
(η5-C5H5){(E)-CHdCHPh)}{P(OMe)3}(PiPr3) (8), which
was isolated as a brown oil in 75% yield. The E
stereochemistry at the carbon-carbon double bond of
the styryl group is supported by the resonances of the
isomer OsH(η5-C5H5)(o-C6H4CHdCH)(PiPr3) (7).
1
In the H NMR spectrum of the isomeric mixture in
benzene-d6, the dCH proton of the vinylidene of 5
displays at 2.80 ppm a double doublet by spin coupling
with the hydride (2.1 Hz) and the phosphorus of the
phosphine (2.1 Hz). The spin coupling with the hydride
was confirmed by a 1H COSY spectrum. The hydride
ligand gives rise to a double doublet with a H-P coup-
ling constant of 29.7 Hz at -14.27 ppm. In the 13C{1H}
NMR spectrum the CR resonance of the vinylidene
appears at 290.2.
In agreement with a hydride ligand disposed cisoid
to the phosphine in 7, the 1H NMR spectrum of the
isomeric mixture also contains at -13.65 ppm a doub-
let with a H-P coupling constant of 44.1 Hz. In the
13C{1H} NMR spectrum, the orthometalated carbon
atom displays at 162.0 ppm a doublet (2J CP ) 2.7 Hz).
The CR and Câ vinylic resonances of the metallacycle
appear at 135.8 and 148.8 ppm, respectively, as doub-
lets with C-P coupling constants of 19.4 and 3.7 Hz.
These spectroscopic data agree well with those obtained
1
vinylic protons, in the H NMR spectrum. The value of
the coupling constant between them (17.4 Hz) is char-
acteristic for this arrangement.7 The 13C{1H} and
31P{1H} NMR spectra of the brown oil are also consis-
tent with the formation of 8. The resonances corre-
sponding to the CR and Câ atoms of the alkenyl ligand
appear in the 13C{1H} NMR spectrum at 136.9 and
130.1 ppm, respectively. The 31P{1H} NMR spectrum
shows two doublets (2J PP ) 32.8 Hz) at 107.2 (P(OMe)3)
and 17.7 (PiPr3) ppm.
for the related complex OsH(η5-C5H4SiPh3)(o-C6H4C-
As a result of a significant contribution of the zwit-
terionic carbene form to the structure of alkenyl com-
plexes, the Câ atom of the alkenyl ligands has a marked
nucleophilic character.8 In agreement with this, the
addition of 1.0 equiv of HBF4‚OEt2 to diethyl ether
solutions of 8 affords the carbene derivative 4, which
was isolated as an orange solid in 71% yield. This is a
rare example of a half-sandwich carbene-osmium com-
plex.9 As far as we know, cyclopentadienyl-carbene-
osmium compounds were unknown until now.
(CH3)dCH)(PiPr3), where the distribution of ligands
around the osmium atom has been confirmed by X-ray
diffraction analysis.5
The constants for the equilibrium between the hy-
dride-vinylidene and metalated species were measured
in the temperature range from 253 to 343 K. The
temperature dependence of the equilibrium gives the
values ∆H° ) -3.6 ( 0.2 kcal mol-1 and ∆S° ) -10.8
( 1.9 cal K-1 mol -1 for the formation of 7. The negative
entropy increment is consistent with the less ordered
character of 5. The value of ∆H° reveals a small
stabilization of the system, probably as a consequence
of the formation of the five-membered ring.
The presence of the carbene ligand in 4 is strongly
supported by the 1H and 13C{1H} NMR spectrum of this
(7) Werner, H.; Esteruelas, M. A.; Otto, H. Organometallics 1986,
5, 2295.
(8) Esteruelas, M. A.; Oro, L. A. Adv. Organomet. Chem. 2001, 47,
1, and references therein.
(9) Weberndo¨rfer, B.; Henig, G.; Werner, H. Organometallics 2000,
19, 4687.
The isomerization of 5 to 7 occurs via the spectro-
scopically undetected Z-alkenyl intermediate 6b, which
evolves into 7 by C-H activation of the ortho C-H bond

2334 Organometallics, Vol. 21, No. 11, 2002
Notes
compound. In the 1H NMR spectrum, the CRH resonance
of the carbene appears at 17.48 ppm, as a multiplet,
whereas the CâH2 group gives rise to two double
NMR spectra were recorded at 293 K and chemical shifts
are expressed in ppm downfield from Me4Si (1H and 13C) and
85% H3PO4 (31P). Coupling constants, J , are given in hertz.
P r ep a r a tion of [OsH(η5-C5H5)(tCCH2P h )(P iP r 3)]BF 4
(3). Rou te a . HBF4‚OEt2 (49 µL, 0.36 mmol) was added to a
solution of OsH(η5-C5H5)(CtCPh)(GePh3)(PiPr3) (141 mg, 0.17
mmol) in 10 mL of diethyl ether. An oily precipitate was
formed. The resulting solution was decanted, and the residue
was washed twice with diethyl ether (2 × 4 mL). A dark brown
solid was obtained. Yield: 95 mg (92%).
2
doublets at 3.91 and 3.30 ppm, with a J HH coupling
3
constant of 15.6 Hz and J HH coupling constants of 9.6
and 6.3 Hz, respectively. In the 13C{1H} NMR spectra,
the CR resonance of the carbene is observed at 285.7
ppm. The 31P{1H} NMR spectrum contains two doublets
(2J PP ) 33.6 Hz) at 89.0 (P(OMe)3) and 25.9 (PiPr3) ppm.
The sequence of reactions shown in Scheme 1 not only
is an elegant manner of obtaining carbene compounds
starting from hydride-carbyne complexes but also rep-
resents a mechanistic alternative to the single migra-
tion, when the barrier to the hydride migration is too
high and the carbyne has a CâHR2 group.
An ionic mechanism of this type (dissociation-migra-
tion-addition) can explain the formation of OsCl2-
(dCHEt)(CO)(PiPr3)2, by reaction of OsHCl2(tCEt)-
(PiPr3)2 with carbon monoxide. It is well known that the
CH2 group of complexes OsHCl2(tCCH2R)(PiPr3)2, simi-
larly to 3, is fairly acidic and can be easily deproto-
nated by treatment with Bro¨nsted bases, to give OsHCl-
(dCdCHR)(PiPr3)2.10 It is also well known that six-
coordinated hydride-vinylidene complexes of the type
OsHCl(dCdCHR)(CO)(PiPr3)2 evolve into the corre-
sponding alkenyl derivatives OsCl{(E)-CHdCHR}(CO)-
(PiPr3)2,11 which react with HCl to afford OsCl2-
(dCCH2R)(CO)(PiPr3)2.11,12
The examination of these reactions and those shown
in Scheme 1 clearly indicates that the function of the
Lewis base is to stabilize the alkenyl intermediate with
regard to the hydride-vinylidene. In this context, it
should be mentioned that for the formation of OsHCl-
(dCdCHR)(PiPr3)2 an alternative pathway to the previ-
ously mentioned deprotonation is the insertion of a
terminal alkyne into the Os-H bond of a monohydride
species, followed by R-elimination in the resulting
alkenyl.13
In conclusion, in addition to the formation of novel
cyclopentadienyl-osmium complexes, this paper shows
that when a carbyne ligand has a CHR2 group, the
Lewis base-assisted hydride-carbyne to carbene trans-
formation can take place via a ionic mechanism involv-
ing (i) dissociation of a proton from the CHR2 group of
the carbyne, (ii) hydride migration to the CR atom of
the resulting vinylidene, (iii) stabilization of the alkenyl
intermediate by coordination of the Lewis base and (iv)
protonation of the CR atom of the alkenyl.
Rou te b. The reaction was made by the same method, but
using OsH(η5-C5H5)(CtCPh)(SiPh3)(PiPr3) (164 mg, 0.21 mmol)
as starting material. A brown solid was obtained. Yield: 115
mg (90%). Anal. Calcd for C22H34BF4OsP: C, 43.57; H, 5.65.
Found: C, 43.72; H, 5.80. IR (Nujol, cm-1): ν(Os-H) 2023;
ν(BF4) 1075. 1H NMR (300 MHz, CDCl3): δ 7.70-7.10 (5 H,
-Ph); 5.75 (5 H, s, η5-C5H5); 3.05 (AB system, 2 H, OstCCH2-,
2
∆ν ) 79.0, J HH ) 19.2); 2.04 (m, 3 H, PCH); 1.20 (dd, 9 H,
3
3
PCHCH3, J HP ) 11.7, J HH ) 7.2); 1.16 (dd, 9 H, PCHCH3,
3J HP ) 11.7, J HH ) 7.2); -12.15 (d, 1 H, Os-H, J HP ) 24).
3
2
13C{1H} NMR (75.4 MHz, CD2Cl2, plus APT): δ 290.9 (-, d,
2
OstC, J CP ) 13.2); 134.3, 131.1, 129.7, 129.4, 129.0, 128.6
(all s, Ph); 88.6 (+, s, η5-C5H5); 58.7 (-, s, CH2); 30.2 (+, d,
PCH, J CP ) 31.8); 19.9, 19.3 (+, s, PCHCH3). 31P{1H} NMR
1
(121.4 MHz, CDCl3): δ 47.9 (s, d in off-resonance). MS
(FAB+): m/z 521 (M+).
Obten tion of th e Equ ilibr iu m Mixtu r e OsH(η5-C5H5)-
{dCdC(H)P h }(P iP r 3) (5)-OsH(η5-C5H5)(o-C6H4CHdCH)-
(P iP r 3) (7). KOH in pellets (96 mg, 1.45 mmol) was added to
a solution of [OsH(η5-C5H5)(tCCH2Ph)(PiPr3)]BF4 (156 mg,
0.26 mmol) in 10 mL of methanol, and the mixture was left to
stir for 2 h. The resulting solution was vacuum-dried, and the
residue was extracted with toluene (10 mL). The filtrate was
vacuum-dried and washed with cold methanol (2 × 2 mL). A
pale brown solid was obtained, which resulted to be a 1:2
mixture of the isomers OsH(η5-C5H5){dCdC(H)Ph}(PiPr3) (5)
and OsH(η5-C5H5)(o-C6H4CHdCH)(PiPr3) (7). Yield: 81 mg
(61%). Anal. Calcd for C22H33OsP: C, 50.94; H, 6.41. Found:
C, 50.65; H, 6.01. IR (Nujol, cm-1): ν(Os-H) 2139, 2110 (w);
ν(OsdCdC) 1620 (m).
Sp ectr oscop ic Da ta for Isom er OsH(η5-C5H5){dCdC-
1
(H)P h }(P iP r 3) (5). H NMR (300 MHz, C6D6): δ 7.52 (dd, 2
3
4
H, Hortho in Ph, J HH ) 7.5, J HH ) 1.5); 7.26 (t, 2 H, Hmeta in
3
3
3
Ph, J HH ) 7.5, J HH ) 7.5); 6.87 (tt, 1 H, Hpara in Ph, J HH
)
7.5, J HH ) 1.5); 5.07 (5 H, s, η5-C5H5); 2.80 (dd, 1 H, OsdCd
4
CH; 4J HH ) 2.1, 4J HP ) 2.1); 1.99 (m, 3 H, PCH); 0.98 (dd, 9 H,
3
3
PCHCH3, J HP ) 13.8, J HH ) 6.9); 0.97 (dd, 9 H, PCHCH3,
3J HP ) 13.8, J HH ) 6.9); -14.27 (d, 1 H, Os-H, J HP ) 29.7,
3
2
4J HH ) 2.1). 13C{1H} NMR (75.4 MHz, C6D6, plus HETCOR):
δ 290.2 (d, OsdCdC, 2J CP ) 11.5); 151.0 (d, Cipso in Ph, 4J CP
)
3.7); 128.6 (s, Cmeta in Ph); 124.2 (s, Cortho in Ph); 123.3 (s, Cpara
in Ph); 112.1 (s, OsdCdC(H)Ph); 83.4 (d, η5-C5H5; 2J CP ) 7.5);
28.1 (d, PCH, J CP ) 30.9); 20.5, 20.0 (s, PCHCH3). 31P{1H}
1
NMR (121.4 MHz, C6D6): δ 43.6 (s, d in off-resonance). MS
Exp er im en ta l Section
(FAB+): m/z 520 (M+).
All reactions were carried out with rigorous exclusion of air
using Schlenk-tube techniques. Solvents were dried by the
usual procedures and distilled under argon prior to use. The
starting materials OsH(η5-C5H5)(CtCPh)(GePh3)(PiPr3) [E )
Si (1), Ge (2)]5 were prepared by the published methods.
Sp ectr oscop ic Da ta for Isom er OsH(η5-C5H5)(o-C6H4-
CHdCH)(P iP r 3) (7). 1H NMR (300 MHz, C6D6): δ 8.33 (dd, 1
H, OsC(H)dC, 3J HH ) 6.9, 3J HP ) 5.4); 8.21, 7.61 (both dd, 1 H
3
4
each, CH in OsC6H4, J HH ) 7.5, J HH ) 1.2); 7.70-7.60 (1 H,
OsC(H)dC(H)); 7.21, 6.94 (both td, 1 H each, CH in OsC6H4,
3J HH ) 7.5, 3J HH ) 7.5, 4J HH ) 1.2); 4.71 (5 H, s, η5-C5H5); 2.09
(10) Bourgault, M.; Castillo, A.; Esteruelas, M. A.; On˜ate, E.; Ruiz,
N. Organometallics 1997, 16, 6. 636.
(11) (a) Esteruelas, M. A.; Oro, L. A.; Valero, C. Organometallics
1995, 14, 3596. (b) Buil, M. L.; Esteruelas, M. A. Organometallics 1999,
18, 1798.
(12) Esteruelas, M. A.; Lahoz, F. J .; On˜ate, E.; Oro, L. A.; Valero,
C.; Zeier, B. J . Am. Chem. Soc. 1995, 117, 7935.
(13) (a) Oliva´n, M.; Eisenstein, O.; Caulton, K. G. Organometallics
1997, 16, 2227. (b) Oliva´n, M.; Clot, E.; Eisenstein, O.; Caulton, K. G.
Organometallics 1998, 17, 3091.
3
3
(m, 3 H, PCH); 0.86 (dd, 9 H, PCHCH3, J HP ) 14.1, J HH
)
3
3
6.9); 0.75 (dd, 9 H, PCHCH3, J HP ) 14.1, J HH ) 6.9); -13.65
(d, 1 H, OsH, J HP ) 44.1). 13C{1H} NMR (75.4 MHz, C6D6,
2
3
plus HETCOR): δ 162.0 (d, CCHd of aryl group, J CP ) 2.7);
3
148.8 (d, OsC(H)dC(H), J CP ) 3.7); 146.5, 122.8 (both s,
tertiary C in OsC6H4); 135.8 (d, OsC(H)dC, 2J CP ) 19.4); 129.1,
122.3 (both s, tertiary C in OsC6H4); 128.1 (OsC of aryl group);

Notes
Organometallics, Vol. 21, No. 11, 2002 2335
3
1
83.3 (d, η5-C5H5, J CP ) 7.5); 28.7 (d, PCH, J CP ) 30.9); 20.9,
19.0 (s, PCHCH3). 31P{1H} NMR (121.4 MHz, C6D6): δ 25.8
(s, d in off-resonance).
(204 mg, 0.32 mmol) in 12 mL of diethyl ether. The subsequent
precipitate was decanted and washed with diethyl ether (3 ×
6 mL). An orange solid was obtained. Yield: 164 mg (71%).
Anal. Calcd for C25H43BF4OsP2: C, 41.10; H, 5.93. Found: C,
P r epar ation of Os(η5-C5H5){(E)-CHdCHP h }{P (OMe3)3}-
(P iP r 3) (8). P(OMe3)3 (100 µL, 0.84 mmol) was added to a
solution of the equilibrium mixture of 5 and 7 (220 mg, 0.42
mmol) in 15 mL of toluene. The mixture was heated to reflux
during 48 h, then filtered and vacuum-dried. The residue was
chromatographed on an alumina column. Diethyl ether eluted
a brown fraction. The resulting solution was vacuum-dried. A
brown oil was obtained. Yield: 204 mg (75%). 1H NMR (300
1
40.76; H, 5.69. H NMR (300 MHz, CDCl3): δ 17.48 (dddd, 1
3
3
3
3
H, OsdCH, J HP ) 10.8, J HH ) 9.6, J HH ) 6.3, J HP ) 2.7);
7.40-7.10 (5 H, -Ph); 5.82 (5 H, s, η5-C5H5); 3.91 (dd, 1 H,
one H of the CH2 group, 2J HH ) 15.6, 3J HH ) 9.6); 3.36 (d, 9 H,
P(OCH3)3, 3J HP ) 11.7); 3.30 (dd, 1 H, one H of the CH2 group,
2J HH ) 15.6, J HH ) 6.3); 2.36 (m, 3 H, PCH); 1.15 (dd, 9 H,
3
3
3
PCHCH3, J HP ) 14.7, J HH ) 7.2); 0.97 (dd, 9 H, PCHCH3,
3J HP ) 14.7, 3J HH ) 7.2). 13C{1H} NMR (75.4 MHz, CDCl3, plus
APT): δ 285.7 (+, br, OsdCH); 135.9 (-, s, Cipso in Ph); 128.8,
128.2 (+, both s, Cortho and Cmeta in Ph); 126.7 (+, s, Cpara in
Ph); 88.9 (+, s, η5-C5H5); 73.3 (-, s, CH2); 53.0 (+, d, OCH3,
3
3
MHz, C6D6): δ 9.73 (ddd, 1 H, OsCHd, J HH ) 17.4, J HP
)
3
8.7, J HP ) 3.0); 7.70-6.90 (6 H, signals of dCHPh); 4.82 (5
H, s, η5-C5H5); 3.25 (d, 9 H, P(OCH3)3, 3J HP ) 11.4); 2.29 (m, 3
3
3
H, PCH); 1.06 (dd, 9 H, PCHCH3, J HP ) 12.9, J HH ) 7.2);
1.01 (dd, 9 H, PCHCH3, 3J HP ) 12.9, 3J HH ) 7.2). 13C{1H} NMR
(75.4 MHz, C6D6, plus APT): δ 145.0 (-, s, Cipso in Ph); 136.9
(+, s, OsC); 135.3, 129.0, 124.3, 123.2 (+, all s, tertiary C’s in
Ph); 130.1 (+, s, OsCHdCH); 79.7 (+, s, η5-C5H5); 51.1 (+, d,
2J CP ) 8.3); 29.3 (+, d, PCH, J CP ) 29.5); 19.3, 19.1 (+, s,
1
PCHCH3). 31P{1H} NMR (121.4 MHz, CDCl3): δ 89.0 (d,
P(OCH3)3, J PP ) 33.6), 25.9 (d, PiPr3, J PP ) 33.6). MS
2
2
(FAB+): m/z 645 (M+), 541 (M+ - CHCH2Ph).
2
1
OCH3, J CP ) 6.0); 28.9 (+, d, PCH, J CP ) 25.3); 20.5, 20.4
(+, s, PCHCH3). 31P{1H} NMR (121.4 MHz, C6D6): δ 107.2 (d,
Ack n ow led gm en t. We thank the DGES (Project
PB98-1591, Programa de Promocio´n General del Cono-
cimiento), for financial support. M.B. thanks the DGA
(Diputacio´n General de Arago´n) for a grant.
P(OCH3)3, J PP ) 32.8), 17.7 (d, PiPr3, J PP ) 32.8). MS
2
2
(FAB+): m/z 644 (M+), 541 (M+ - CHdCHPh).
P r ep a r a tion of [Os(η5-C5H5)(dCHCH 2P h ){P (OMe3)3}-
(P iP r 3)]BF 4 (4). HBF4‚OEt2 (45 µL, 0.33 mmol) was added to
a solution of Os(η5-C5H5){(E)-CHdCHPh}{P(OCH3)3}(PiPr3)
OM011077E