α-Substituted alkenyl and a-disubstituted alkylidene complexes with the OsCl(CO)(PiPr3)2 skeleton

Article abstract of DOI:10.1021/om7002915

Complex Os(η²-PhC≡CPh)(CO)(PⁱPr ₃)₂ (1) reacts with 1 equiv of HBF₄ to give the hydride species [OsH(η²-PhC≡CPh)(CO)(PⁱPr ₃)₂]BF₄ (2), which affords the α-substituted alkenyl compound Os{(E)-C(Ph)=CHPh}Cl(CO)(P ⁱPr₃)₂ (3) by treatment with NaCl. Complex 3 reacts with Bronsted acids to give a-disubstituted alkylidene derivatives. Thus, the reaction with 1 equiv of HBFo₄ yields the cationic complex [OsCl{=C(Ph)CH₂Ph}(CO)(PⁱPr ₃)₂][BF₄] (4). The treatment of 3 with 1 equiv of HCl gives the neutral alkylidene derivative OsCl₂{=C(Ph)CH ₂Ph}(CO)(PⁱPr₃)₂ (5), while the reaction with an excess of HCl yields the anionic alkylidene complex [HP ¹-Pr₃][OsCl₃{=C(Ph)CH₂Ph}(CO)(P ⁱPr₃)](6).

Full text of DOI:10.1021/om7002915

3260
Organometallics 2007, 26, 3260-3263
r-Substituted Alkenyl and r-Disubstituted Alkylidene Complexes
with the OsCl(CO)(PiPr3)2 Skeleton
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 March 27, 2007
Summary: Complex Os(η2-PhCtCPh)(CO)(PiPr3)2 (1) reacts
with 1 equiV of HBF4 to giVe the hydride species [OsH(η2-
PhCtCPh)(CO)(PiPr3)2]BF4 (2), which affords the R-substi-
tuted alkenyl compound Os{(E)-C(Ph)dCHPh}Cl(CO)(PiPr3)2
(3) by treatment with NaCl. Complex 3 reacts with Brønsted
acids to giVe R-disubstituted alkylidene deriVatiVes. Thus, the
reaction with 1 equiV of HBF4 yields the cationic complex
[OsCl{dC(Ph)CH2Ph}(CO)(PiPr3)2][BF4] (4). The treatment
of 3 with 1 equiV of HCl giVes the neutral alkylidene deriVatiVe
OsCl2{dC(Ph)CH2Ph}(CO)(PiPr3)2 (5), while the reaction with
an excess of HCl yields the anionic alkylidene complex [HPi-
Pr3][OsCl3{dC(Ph)CH2Ph}(CO)(PiPr3)] (6).
the hydride from the metal to the carbon atom, it has been argued
that steric effects are mainly responsible for this limitation.8a,9
The insertion of terminal alkynes into the Os-H bond of
OsHCl(CO)(PiPr3)2 selectively leads to alkenyl derivatives with
E stereochemistry around the C-C double bond. These com-
pounds react with electrophiles by addition to the RC(sp2) atom.
Thus, the selective formation of alkylidene compounds contain-
ing a hydrogen atom at the CR carbon of the alkylidene ligand
takes place (eq 1).8d,e,10 Because R-substituted alkenyl and
R-disubstituted alkylidene complexes with the OsCl(CO)(PiPr3)2
skeleton are unknown, while related osmium compounds with
triphenylphosphine have been reported,11 one might think that
the lack of reactivity for internal alkynes could be not only a
consequence of a restricted coordination but also due to the low
stability of the resulting R-substituted alkenyl derivatives; that
is, the lack of reactivity for internal alkynes could be not only
kinetic but also thermodynamic in origin.
The five-coordinate complex OsHCl(CO)(PiPr3)2 is an
1
important homogeneous catalyst for the reduction of unsaturated
organic substrates,2 the addition of silanes to alkynes,3 the
dehalogenation of polychloroarenes,4 and C-C coupling reac-
tions including the dimerization of terminal alkynes to bu-
tatrienes,5 and the ring-opening metathesis polymerization of
norbornene and 2,5-norbornadiene.6 Furthermore, it has been
one of the cornerstones in the development of modern organo-
metallic osmium chemistry.7
Among the stoichiometric reactions of this complex, the
addition of the Os-H bond across the CtC bond of alkynes to
afford alkenyl derivatives has received particular attention,8 by
its connection with the catalytic processes involving alkynes
and as an entry to other interesting organometallic compounds.7,9
However, it is limited to terminal alkynes. Since the addition
of the alkyne to the metal first occurs followed by migration of
The problem is certainly kinetic in origin; R-substituted
alkenyl (Scheme 1) and R-disubstituted alkylidene (Scheme 2)
complexes not only can be prepared but also are stable.
The π-diphenylacetylene group of the previously reported
complex Os(η2-PhCtCPh)(CO)(PiPr3)2 (1) acts as a four-
electron donor ligand.12 Thus, in spite of the four coordination,
its metal center has nucleophilic character, reacting with
electrophiles. Treatment at room temperature of dichloromethane
solutions of 1 with 1.0 equiv of HBF4·OEt2 leads to the hydride
derivative [OsH(η2-PhCtCPh)(CO)(PiPr3)2]BF4 (2), as a result
of the addition of the proton of the acid to the metal, which
undergoes oxidation. Complex 2 is related to compounds [OsH-
(dCdCHR)(η2-HCtCR)(PiPr3)2]BF4 (R ) H, Cy, Ph,13 C(O-
H)Ph2, C(OH)Me214) and [OsH(dCdCdCPh2)(η2-HCtCH)(Pi-
Pr3)2]BF4,15 which, on the basis of an X-ray diffraction study
on [OsH(dCdCH2)(η2-HCtCH)(PiPr3)2]BF4,13 have been de-
* Corresponding author. E-mail: maester@unizar.es.
(1) Esteruelas, M. A.; Werner, H. J. Organomet. Chem. 1986, 303, 221.
(2) (a) Sa´nchez-Delgado, R. A.; Rosales, M.; Esteruelas, M. A.; Oro, L.
A. J. Mol. Catal. A: Chem. 1995, 96, 231. (b) Esteruelas, M. A.; Oro, L.
A. Chem. ReV. 1998, 98, 577.
(3) Esteruelas, M. A.; Oro, L. A.; Valero, C. Organometallics 1991, 10,
462.
(4) D´ıaz, J.; Esteruelas, M. A.; Herrero, J.; Moralejo, L.; Oliva´n, M. J.
Catal. 2000, 195, 187.
(5) Esteruelas, M. A.; Herrero, J.; Lo´pez, A. M.; Oliva´n, M. Organo-
metallics 2001, 20, 3202.
(6) Cobo, N.; Esteruelas, M. A.; Gonza´lez, F.; Herrero, J. Lo´pez, A.
M.; Lucio, P.; Oliva´n, M. J. Catal. 2004, 223, 319.
(7) (a) Esteruelas, M. A.; Oro, L. A. AdV. Organomet. Chem. 2001, 47,
1.
(8) (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) Esteruelas, M. A.; Lahoz, F. J.; On˜ate, E.; Oro,
L. A.; Zeier, B. Organometallics 1994, 13, 1662. (d) Esteruelas, M. A.;
Oro, L. A.; Valero, C. Organometallics 1995, 14, 3596. (e) Buil, M. L.;
Esteruelas, M. A. Organometallics 1999, 18, 1798. (f) Marchenko, A. V.;
Ge´rard, H.; Eisenstein, O.; Caulton, K. G. New J. Chem, 2001, 25, 1244.
(g) Marchenko, A. V.; Ge´rard, H.; Eisenstein, O.; Caulton, K. G. New J.
Chem. 2001, 25, 1382.
(10) Esteruelas, M. A.; Lahoz, F. J.; On˜ate, E.; Oro, L. A.; Valero, C.;
Zeier, B. J. Am. Chem. Soc. 1995, 117, 7935.
(11) Hill, A. F.; Wilton-Ely, J. D. E. T. J. Chem. Soc., Dalton Trans.
1998, 3501.
(12) Espuelas, J.; Esteruelas, M. A.; Lahoz, F. J.; Lo´pez, A. M.; Oro, L.
A.; Valero, C. J. Organomet. Chem. 1994, 468, 223.
(13) Barrio, P.; Esteruelas, M. A.; On˜ate, E. Organometallics 2003, 22,
2472.
(14) Bolan˜o, T.; Castarlenas, R.; Esteruelas, M. A.; Modrego, J.; On˜ate,
E. J. Am. Chem. Soc. 2005, 127, 11184.
(9) Esteruelas, M. A.; Lo´pez, A. M.; Oliva´n, M. Coord. Chem. ReV. 2007,
251, 795.
(15) Bolan˜o, T.; Castarlenas, R.; Esteruelas, M. A.; On˜ate, E. J. Am.
Chem. Soc. 2006, 128, 3965.
10.1021/om7002915 CCC: $37.00 © 2007 American Chemical Society
Publication on Web 05/17/2007

Notes
Organometallics, Vol. 26, No. 13, 2007 3261
Scheme 1
Scheme 2
scribed as bipyramidal species with apical phosphines and
inequivalent angles within the Y-shaped equatorial plane. The
π-alkyne group, which also acts in this compound as a four-
electron donor ligand, lies in the foot of the Y.16
Complex 2 is isolated as a yellow solid in 94% yield. The
presence of a hydride ligand in this compound is strongly
supported by its 1H NMR spectrum, which at 233 K in
dichloromethane shows a triplet at -7.37 ppm with an H-P
coupling constant of 25.5 Hz. In accordance with the che-
mical shifts found for other osmium complexes where the
alkynes also act as four-electron donor ligands,12-15,17 the
acetylenic resonance in the 13C{1H} NMR spectrum is observed
at 165.4 ppm. The 31P{1H} NMR spectrum contains a singlet
at 42.3 ppm.
genation of the alkyne to Z-stilbene.20 Furthermore, interestingly,
the reaction rate increases in the solvent sequence benzene <
1,2-dichloroethane < 2-propanol. The formation of 3 according
to Scheme 1 suggests that, under the catalytic conditions, the
coordination of the alkyne to the metal center of the catalyst
produces the dissociation of the chloride ligand to afford 2,
which subsequently evolves to 3. Polar solvents favor the
dissociation and therefore the catalysis.
Complex 3 is the entry key to the preparation of cationic,
neutral, and anionic R-disubstituted alkylidene derivatives, which
are easily formed from reactions with acids (Scheme 2), in
agreement with the expected nucleophilic character of the Câ
atom of an alkenyl ligand coordinated to osmium.9,21
Treatment of dichloromethane solutions of 3 with 1.0 equiv
of HBF4·OEt2 leads to the cationic five-coordinate alkylidene
compound [OsCl{dC(Ph)CH2Ph}(CO)(PiPr3)2]BF4 (4), which
is isolated as a yellow solid in 87% yield. This compound has
been characterized by elemental analysis, IR and 1H, 13C{1H},
and 31P{1H} NMR spectroscopy, and an X-ray crystallographic
study. A view of the structure of this compound is shown in
Figure 1.
The geometry around the osmium atom can be rationalized
as a square pyramid with the alkylidene located at the apex.
The four atoms, P(1), P(2), Cl, and C(15), forming the base,
are approximately in a plane, whereas the osmium atom is
located 0.465(1) Å above this plane toward the apical position.
The phosphine ligands are pseudo-trans disposed with a P(1)-
Os-P(2) angle of 155.78(3)°. Similarly, the chloride and
carbonyl group lie pseudo-trans disposed with a Cl-Os-C(15)
angle of 156.41(10)°. The separation of 1.888(3) Å between
the osmium atom and the alkylidene supports the Os-C(1)
double bond formulation.10,14,22
In the presence of NaCl, the methanol solutions of 2 evolve
to the R-substituted alkenyl derivative Os{(E)-C(Ph)dCHPh}-
Cl(CO)(PiPr3)2 (3), as a consequence of the migratory insertion
of the CtC triple bond of the alkyne into the Os-H bond of 2
and of the coordination of the chloride ligand to the osmium
atom. We note that the related complex Os{(E)-C(Ph)dCHPh}-
Cl(CS)(PPh3)2 has been previously prepared by Roper by
treatment of Os(η2-PhCtCPh)(CS)(PPh3)2 with HCl.18 Complex
3, which precipitates in the reaction medium, is isolated as a
dark red solid in 70% yield. The presence of the alkenyl ligand
in the compound is strongly supported by the 13C{1H} NMR
spectrum, which, in agreement with other alkenyl-osmium
complexes,8,11,18,19 shows the CR(sp2) and Câ(sp2) resonances
at 140.0 and 134.5 ppm, respectively. In accordance with the
trans disposition of the phosphine ligands, the 31P{1H} NMR
spectrum contains a singlet at 16.3 ppm.
The formation of 3 via 2 allows the rationalization of another
observation that demands some explanation. The key step for
the selective hydrogenation of alkynes to olefins catalyzed by
OsHCl(CO)(PiPr3)2 is the reaction of chloro-alkenyl intermedi-
ates, related to 3, with molecular hydrogen.8b In spite of the
fact that 3 cannot be obtained from OsHCl(CO)(PiPr3)2 and
diphenylacetylene, this hydride complex catalyzes the hydro-
The 13C{1H} and 31P{1H} NMR spectra of 4 are consistent
with Figure 1. In the 13C{1H} NMR spectrum in dichlo-
romethane-d2, the most noticeable resonance is a triplet (JC-P
) 6 Hz) at 285.8 ppm due to the CR atom of the alkylidene. In
agreement with the pseudo-trans disposition of the phosphine
ligands, the 31P{1H} NMR spectrum contains a singlet at
41.2 ppm.
(16) An L ligand with σ- and π-donating capabilities stabilizes the
trigonal bipyramid with the L ligand in the foot of the Y. See: Riehl, J.-F.;
Jean, Y.; Eisenstein, O; Pe´lissier, M. Organometallics 1992, 11, 729.
(17) Carbo´, J. J.; Crochet, P.; Esteruelas, M. A.; Jean, Y.; Lledo´s, A.;
Lo´pez, A. M.; On˜ate, E. Organometallics 2002, 21, 305.
(18) Elliot, G. P.; Roper, W. R. J. Organomet. Chem. 1983, 250, C5.
(19) See for example: (a) Spivak, G. J.; Caulton, K. G. Organometallics
1998, 17, 5260. (b) Baya, M.; Esteruelas, M. A. Organometallics 2002,
21, 2332. (c) Barrio, P.; Esteruelas, M. A.; On˜ate, E. J. Am. Chem. Soc.
2004, 126, 1946. (d) Xue. P.; Zhu, J.; Hung, H. S. Y.; Williams, I. D.; Lin,
Z.; Jia, G. Organometallics 2005, 24, 4896. (e) Buil, M. L.; Esteruelas, M.
A.; Goni, E.; Oliva´n, M.; On˜ate, E. Organometallics 2006, 25, 3076.
(20) Esteruelas, M. A.; Sola, E.; Oro, L. A.; Meyer, U.; Werner, H.
Angew. Chem., Int. Ed. Engl. 1988, 27, 1563.
(21) Esteruelas, M. A.; Lo´pez, A. M. Organometallics 2005, 24, 3584.

3262 Organometallics, Vol. 26, No. 13, 2007
Notes
osmium atom. Complex 5 is isolated as an orange solid in 53%
yield. In agreement with 4, in the 13C{1H} NMR spectrum in
benzene-d6, the alkylidene OsC resonance appears at 302.1 ppm
as a triplet with a C-P coupling constant of 6 Hz. The 31P-
{1H} NMR spectrum shows a singlet at 0.0 ppm.
Bubbling HCl through a toluene solution of 3 for 0.5 h
results in the formation of the anionic complex [HPiPr3]-
[OsCl3{dC(Ph)CH2Ph}(CO)(PiPr3)] (6) via 5. Complex 6 was
isolated as orange crystals suitable for an X-ray diffraction study
in 40% yield. Figure 2 shows a view of the structure of this
compound.
The geometry around the osmium atom can be described as
a distorted octahedron with the chloride ligands in a fac
disposition. The three separations between the latter and the
metal are different, 2.4446(7) (Os-Cl(1)), 2.4813(7) (Os-Cl-
(2)), and 2.5127(7) (Os-Cl(3)) Å, with that being trans to the
phosphine ligand the shortest and that trans to the alkylidene
group the longest one. The Os-C(1) bond length of 1.929(3)
Å compares well with the Os-alkylidene separation in 4 and
supports the Os-C(1) double bond formulation.
Figure 1. Molecular diagram of 4. Selected bond lengths (Å) and
angles (deg): Os-C(1) 1.888(3), Os-C(15) 1.835(4), Os-Cl
2.3839(8), Os-P(1) 2.4592(8), Os-P(2) 2.4630(9); C(1)-Os-
C(15) 91.79(14), C(1)-Os-Cl 111.79(10), C(1)-Os-P(1) 105.77-
(10), C(1)-Os-P(2) 98.46(10), C(15)-Os-Cl 156.41(10), C(15)-
Os-P(1) 89.04(10), C(15)-Os-P(2) 89.94(10), Cl-Os-P(1)
84.20(3), Cl-Os-P(2) 87.15(3), P(1)-Os-P(2) 155.78(3), C(2)-
C(1)-C(8) 115.0(3), Os-C(1)-C(2) 132.0(2), Os-C(1)-C(8)
112.5(2).
In the 13C{1H} NMR spectrum of 6 in dichloromethane-d2,
the alkylidene OsC resonance appears at 297.0 ppm as a doub-
let with a C-P coupling constant of 7.0 Hz. The 31P{1H}
NMR spectrum contains two singlets at 24.5 (HPiPr3) and 13.2
(PiPr3) ppm.
In conclusion, the lack of reaction between OsHCl(CO)(Pi-
Pr3)2 and nonactivated internal alkynes is kinetic in origin.
Although this hydride does not react with diphenylacetylene,
the R-substituted alkenyl complex Os{(E)-C(Ph)dCHPh}-
Cl(CO)(PiPr3)2 can be obtained by consecutive reaction of Os-
(η2-PhCtCPh)(CO)(PiPr3)2 with H+ and Cl-. Furthermore, it
should be mentioned that the steric hindrance imposed by the
substituent at the CR atom does not play a determinant role on
the stability of the system. Thus, the alkenyl complex Os{(E)-
C(Ph)dCHPh}Cl(CO)(PiPr3)2 proves to be the entry key to
cationic, neutral, and anionic R-disubstituted alkylidene
derivatives.
Experimental Section
Figure 2. Molecular diagram of 6. Selected bond lengths (Å) and
angles (deg): Os-C(1) 1.929(3), Os-C(15) 1.820(3), Os-Cl(1)
2.4446(7), Os-Cl(2) 2.4813(7), Os-Cl(3) 2.5127(7), Os-P(1)
2.3920(8); C(1)-Os-C(15) 92.76(12), C(1)-Os-Cl(1) 96.12(8),
C(1)-Os-Cl(2) 91.51(9), C(1)-Os-Cl(3) 175.13(9), C(1)-Os-
P(1) 93.64(8), C(15)-Os-Cl(1) 85.66(9), C(15)-Os-Cl(2) 170.05-
(9), C(15)-Os-Cl(3) 92.09(9), C(15)-Os-P(1) 91.70(9), P(1)-
Os-Cl(1) 170.00(3), P(1)-Os-Cl(2) 96.99(2), P(1)-Os-Cl(3)
85.91(3), Cl(1)-Os-Cl(2) 84.96(2), Cl(1)-Os-Cl(3) 84.56(3), Cl-
(2)-Os-Cl(3) 83.74(3), Os-C(1)-C(2) 125.0(2), Os-C(1)-C(8)
124.0(2).
General Methods and Instrumentation. 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 material Os(η2-C2Ph2)(CO)(Pi-
Pr3)2 (1) was prepared by the published method.12 In the NMR
spectra, chemical shifts (expresed in ppm) are referenced to residual
solvent peaks (1H and 13C) or external 85% phosphoric acid (31P).
1
Coupling constants, J and N (N ) JH-P + JH-P′ for H; N ) JC-P
+ JC-P′ for 13C), are given in hertz.
Preparation of [OsH(η2-C2Ph2)(CO)(PiPr3)2]BF4 (2). A red
solution of 1 (252 mg, 0.35 mmol) in 3 mL of dichloromethane
was treated with a solution of HBF4 in diethyl ether (54%, 48 µL,
0.35 mmol). The brown solution obtained was stirred at room
temperature for 10 min, and the solvent was removed in vacuo.
Diethyl ether (6 mL) was added, and the mixture was stirred at 0
°C for 30 min. The yellow solid formed was separated by
decantation, washed with cold diethyl ether (2 × 3 mL), and dried
in vacuo. Yield: 266 mg (94%). Anal. Calcd for C33H53BF4-
OOsP2: C, 49.25; H, 6.64. Found: C, 48.77; H, 6.58. IR (Nujol,
cm-1): ν(OsH) 2192 (w), ν(CO) 1930 (vs), ν(CtC) 1885 (m),
The addition of 1.0 equiv of HCl in toluene to toluene
solutions of 3 affords the dichloro-alkylidene derivative
OsCl2{dC(Ph)CH2Ph}(CO)(PiPr3)2 (5), as a result of the
addition of the proton of the acid to the Câ atom of the alkenyl
group of 3 and the coordination of the chloride ligand to the
(22) (a) Brumaghim, J. L.; Girolami, G. S. Chem. Commun. 1999, 953.
(b) Werner, H.; Stu¨er, W.; Wolf, J.; Laubender, M.; Weberndo¨rfer, B;
Herbst-Irmer, R.; Lehman, C. Eur. J. Inorg. Chem. 1999, 1889. (c)
Castarlenas, R.; Esteruelas, M. A.; On˜ate, E. Organometallics 2001, 20,
2294. (d) Gusev, D. G. Lough, A. J. Organometallics 2002, 21, 2601. (e)
Weberndo¨rfer, B.; Henig, G.; Hockless, D. C. R.; Bennet, M. A.; Werner,
H. Organometallics 2003, 22, 744. (f) Esteruelas, M. A.; Gonza´lez, A. I.;
Lo´pez, A. M.; On˜ate, E. Organometallics 2004, 23, 4858. (g) Castarlenas,
R.; Esteruelas, M. A.; On˜ate, E. Organometallics 2005, 24, 4343. (h) Wen,
T. B.; Hung, W. Y.; Sung, H. H. Y.; Williams, I. D.; Jia, G. J. Am. Chem.
Soc. 2005, 127, 2856. (i) Esteruelas, M. A.; Ferna´ndez-Alvarez, F. J.; Oliva´n,
M.; On˜ate, E. J. Am. Chem. Soc. 2006, 128, 4596.
1
ν(BF4) 1066 (br, vs). H NMR (300 MHz, CD2Cl2, 293 K): 7.44
(m, 4H, Ph), 7.35 (m, 2H, Ph), 7.07 (m, 4H, Ph), 2.63 (m, 6H,
PCH), 1.36 (dvt, JH-H ) 7.2, N ) 15.9, 18H, PCHCH3), 1.22
(dvt, JH-H ) 7.2, N ) 15.6, 18H, PCHCH3), -7.37 (br t, 1H, OsH).
1H NMR (300 MHz, CD2Cl2, 233 K): -7.37 (t, JH-P ) 25.5, 1H,
OsH). 31P{1H} NMR (121.4 MHz, CD2Cl2, 233 K): δ 42.3 (s).

Notes
Organometallics, Vol. 26, No. 13, 2007 3263
13C{1H} NMR (75.4 MHz, CD2Cl2, 233 K): δ 177.2 (t, JC-P ) 9,
CO), 165.4 (s, tC), 137.2 (s, CipsoPh), 128.9, 128.7, 125.0 (all s,
Ph), 28.8 (vt, N ) 30, PCH), 21.0, 20.2 (both s, PCHCH3).
Preparation of Os{(E)-C(Ph)dCHPh}Cl(CO)(PiPr3)2 (3).
Methanol (5 mL) was added to a mixture of 2 (188 mg, 0.23 mmol)
and NaCl (34 mg, 0.58 mmol). A dark red solid began to precipitate
immediately. The suspension was stirred at room temperature for
5 h, and the dark red solid was separated by decantation. It was
repeatedly washed with methanol (5 × 3 mL) and dried in vacuo.
Yield: 124 mg (70%). Anal. Calcd for C33H53ClOOsP2: C, 52.61;
H, 7.09. Found: C, 52.23; H, 6.91. IR (Nujol, cm-1): ν(CO) 1900
(vs), ν(CdC) 1589 (w), 1575 (w), 1542 (m). 1H NMR (300 MHz,
C6D6, 293 K): 7.69 (m, 2H, Ph), 7.05-6.78 (m, 9H, dCH + Ph),
2.83 (m, 6H, PCH), 1.19 (dvt, JH-H ) 6.9, N ) 13.5, 18H,
PCHCH3), 1.17 (dvt, JH-H ) 6.9, N ) 13.5, 18H, PCHCH3). 31P-
{1H} NMR (121.4 MHz, C6D6, 293 K): δ 16.3 (s). 13C{1H}-APT
NMR (75.4 MHz, C6D6, 293 K): δ 184.8 (t, JC-P ) 10, CO), 140.0
(br, Os-C), 140.7 (s, CipsoPh), 134.5 (br, dCHPh), 130.8, 129.4,
128.6, 128.3, 126.8, 124.6 (all s, Ph), 25.0 (vt, N ) 23, PCH),
20.3, 20.1 (both s, PCHCH3).
Found: C, 49.95; H, 6.73. IR (Nujol, cm-1): ν(CO) 1930 (vs),
ν(CdC) 1596 (m). H NMR (300 MHz, C6D6, 293 K): 7.42 (d,
1
JH-H ) 7.5, 2H, o-Ph), 7.21-6.93 (m, 8H, Ph), 5.28 (s, 2H, CH2),
2.84 (m, 6H, PCH), 1.28 (dvt, JH-H ) 6.6, N ) 13.5, 18H,
PCHCH3), 1.21 (dvt, JH-H ) 6.9, N ) 13.5, 18H, PCHCH3). 31P-
{1H} NMR (121.4 MHz, C6D6, 293 K): δ 0.0 (s). 13C{1H}-APT
NMR (75.4 MHz, CD2Cl2, 243 K): δ 302.1 (t, JC-P ) 6, OsdC),
178.5 (t, JC-P ) 9, CO), 165.0, 137.3 (both s, CipsoPh), 130.0, 129.7,
127.6, 127.2, 125.8, 125.2 (all s, Ph), 65.4 (s, CH2), 27.0 (vt, N )
23, PCH), 19.9, 19.5 (both s, PCHCH3).
Preparation of [HPiPr3][OsCl3{dC(Ph)CH2Ph}(CO)(PiPr3)]
(6). HCl was bubbled through a solution of 3 (121 mg, 0.16 mmol)
in 5 mL of toluene at 0 °C for 30 min. The solution was
concentrated in vacuo to ca. 0.5 mL, and the addition of 5 mL of
pentane caused the precipitation of an orange solid, which was
separated by decantation, washed with pentane (2 × 5 mL), and
1
dried in vacuo. The solid was characterized by H and 31P{1H}
NMR spectroscopy as a mixture of 5 and 6 in a 1:1.85 molar ratio.
Slow crystallization of this solid in toluene/pentane gave complex
6 as orange crystals. Yield: 53 mg (40%). Anal. Calcd for C33H55-
Cl3OOsP2: C, 47.97; H, 6.71. Found: C, 47.91; H, 6.86. IR (Nujol,
Preparation of [OsCl{dC(Ph)CH2Ph}(CO)(PiPr3)2]BF4 (4).
A solution of 3 (113 mg, 0.15 mmol) in 4 mL of dichloromethane
was treated with a solution of HBF4 in diethyl ether (54%, 21 µL,
0.15 mmol). After 30 min stirring at room temperature, the solution
was concentrated to ca. 0.5 mL, and 10 mL of diethyl ether was
added. A yellow solid precipitated, which was recrystallized from
acetone/diethyl ether. Yield: 110 mg (87%). Anal. Calcd for C33H54-
BClF4OOsP2: C, 47.12; H, 6.47. Found: C, 46.96; H, 6.51. IR
(Nujol, cm-1): ν(CO) 1961 (vs), ν(CdC) 11587 (w), ν(BF4) 1058
1
cm-1): ν(PH) 2379 (m), ν(CO) 1932 (vs), ν(CdC) 1600 (w). H
NMR (300 MHz, CD2Cl2, 293 K): 8.35 (dq, JH-P ) 522, JH-H
)
4.2, 1H, PH), 7.56 (d, JH-H ) 7.2, 2H, Ph), 7.35 (d, JH-H ) 13.5,
1H, CH2), 7.29-7.15 (m, 5H, Ph), 7.00 (m, 3H, Ph), 2.81 (m, 3H,
PCH, HPiPr3), 2.59 (m, 3H, PCH, PiPr3), 2.49 (dd, JH-H ) 13.5,
JH-P ) 3.3, 1H, CH2), 1.56 (dd, JH-H ) 7.2, JH-P ) 16.5, 18H,
PCHCH3, HPiPr3), 1.46 (dd, JH-H ) 7.2, JH-P ) 14.0, 9H, PCHCH3,
PiPr3), 1.25 (dd, JH-H ) 7.4, JH-P ) 13.7, 9H, PCHCH3, PiPr3).
31P{1H} NMR (121.4 MHz, CD2Cl2, 293 K): δ 24.5 (s, HPiPr3),
13.2 (s, PiPr3). 13C{1H}-APT NMR (75.4 MHz, CD2Cl2, 293 K):
δ 297.0 (d, JC-P ) 7, OsdC), 177.3 (d, JC-P ) 10, CO), 168.0,
136.5 (both s, CipsoPh), 131.0, 128.1, 127.5, 127.1, 125.5, 123.1
(all s, Ph), 67.0 (s, CH2), 29.9 (br d, JC-P ) 29, PCH, PiPr3), 19.8,
(d, JC-P ) 41, PCH, HPiPr3), 19.5 (br, PCHCH3, PiPr3), 17.9 (d,
JC-P ) 3, PCHCH3, HPiPr3).
1
(br, s). H NMR (300 MHz, CD2Cl2, 293 K): 7.75 (m, 3H, Ph),
7.50 (m, 2H, Ph), 7.12 (m, 3H, Ph), 6.78 (m, 2H, Ph), 4.94 (s, 2H,
CH2), 3.00 (m, 6H, PCH), 1.32 (dvt, JH-H ) 7.2, N ) 14.7, 18H,
PCHCH3), 1.27 (dvt, JH-H ) 7.5, N ) 15.3, 18H, PCHCH3). 31P-
{1H} NMR (121.4 MHz, CD2Cl2, 293 K): δ 41.2 (s). 13C{1H}-
APT NMR (75.4 MHz, CD2Cl2, 253 K): δ 285.8 (t, JC-P ) 6,
OsdC), 181.0 (t, JC-P ) 8, CO), 158.5 (s, CipsoPh), 134.6, 134.5,
130.2, 129.0, 128.9, 127.6, 127.0 (all s, Ph), 62.8 (s, CH2), 26.3
(vt, N ) 26, PCH), 19.8, 19.5 (both s, PCHCH3).
Acknowledgment. Financial support from the MEC of Spain
(Proyect CTQ2005-00656) and Diputacio´n General de Arago´n
(E35) is acknowledged.
Preparation of OsCl2{dC(Ph)CH2Ph}(CO)(PiPr3)2 (5). A
solution of HCl in toluene (0.28 M, 0.43 mL, 0.12 mmol) was added
dropwise to a green solution of 3 (91 mg, 0.12 mmol) in 6 mL of
toluene at 0 °C. The resulting dark brown solution was stirred for
30 min at room temperature, and then, it was concentrated in vacuo
to ca. 0.5 mL. The addition of 4 mL of pentane caused the
precipitation of an orange solid, which was separated by decantation,
washed with pentane (3 × 2 mL), and dried in vacuo. Yield: 50
mg (53%). Anal. Calcd for C33H54Cl2OOsP2: C, 50.18; H, 6.89.
Supporting Information Available: Crystal structure deter-
minations and CIF files giving crystal data for compounds 4 and
6. This material is available free of charge via the Internet at
http://pubs.acs.org.
OM7002915