Formation of cationic half-sandwich osmium-vinylidene complexes from [Os(η5-C5H5)(Pi Pr3)2]+ and terminal alkynes

Article abstract of DOI:10.1021/om0104565

Ab initio calculations on the model complexes [Os(η⁵-C₅H₅)(η²-HC≡CH) (PH₃)₂]⁺ (1), [OsH(η⁵-C₅H₅)-(C≡CH) (PH₃)₂]⁺

Full text of DOI:10.1021/om0104565

Organometallics 2001, 20, 4291-4294
4291
F or m a tion of Ca tion ic Ha lf-Sa n d w ich
Osm iu m -Vin ylid en e Com p lexes fr om
[Os(η5-C5H5)(P iP r 3)2]+ a n d Ter m in a l Alk yn es
Miguel Baya, Pascale Crochet, Miguel A. Esteruelas,* Ana M. Lo´pez,
J avier Modrego, and Enrique On˜ate
Departamento de Quı´mica Inorga´nica-Instituto de Ciencia de Materiales de Arago´n,
Universidad de Zaragoza-CSIC, 50009 Zaragoza, Spain
Received May 30, 2001
Sch em e 1
Summary: Ab initio calculations on the model complexes
[Os(η5-C5H5)(η2-HCtCH)(PH3)2]+ (1), [OsH(η5-C5H5)-
(CtCH)(PH3)2]+ (2), and [Os(η5-C5H5)(dCdCH2)(PH3)2]+
(3) indicate that the thermodynamic stability of these
compounds decreases according to the sequence 3 > 1 >
2. According to this, the vinylidene complexes [Os(η5-
C5H5)(dCdCHR)(PiPr3)2]PF6 (R ) Cy (8), Ph (9)) are
prepared by deprotonation of [OsH(η5-C5H5)(CtCR)-
(PiPr3)2]PF6 (R ) Cy (4), Ph (5)) with KOH in methanol
and subsequent protonation of the resulting alkynyl
derivatives Os(η5-C5H5)(CtCR)(PiPr3)2 (R ) Cy (6), Ph
(7)). The X-ray structure of [Os(η5-C5H5)(dCdCHPh)-
(PiPr3)2]PF6 (9) is also reported.
π-alkyne intermediates followed by tautomerization.
The isomerization of the π-alkynes into vinylidenes
appears to occur by two alternative pathways (a and b
in Scheme 1), via either intramolecular 1,2-hydrogen
migration or hydride-alkynyl species.6 It is taken for
granted that once the π-alkyne intermediates are formed,
the pathways a and b are competitive and the choice of
one or the other is determined by the electron density
of the metallic fragment. Basic metallic fragments favor
pathway b . Thus, it has been observed that Ru(η5-
C5Me5)Cl(iPr2PCH2CH2PiPr2) reacts with terminal al-
kynes in the presence of NaBPh4 to give vinylidene
derivatives via hydride-alkynyl-ruthenium(IV) inter-
mediates, while under the same conditions the forma-
tion of the analogous vinylidene complexes containing
the less basic [Ru(η5-C5H5)(iPr2PCH2CH2PiPr2)]+ unit
proceeds through 1,2-hydrogen migration.5c,f
On the other hand, for osmium, we have observed that
in the presence of terminal alkynes the Os(η5-C5H5)Cl-
(PiPr3) unit affords vinylidene compounds, via π-alkyne
intermediates by 1,2-hydrogen shift,7 while the less
basic [Os(η5-C5H5)(PiPr3)2]+ metallic fragment gives
the hydride-alkynyl-osmium(IV) derivatives [OsH(η5-
C5H5)(CtCR)(PiPr3)2]+;8 i.e., the metallic fragment with
higher basicity favors pathway a .
Cationic half-sandwich osmium vinylidene complexes
are very scarce. The compounds of this type previously
reported include [Os(η5-C5Me5)(dCdCHR)(CO)(PPh3)]-
PF6 (R ) tBu, Ph),1 [Os(η5-C5H5)(dCdCHR)(CO)(PiPr3)]-
BF4 (R ) Ph, CdCH(CH2)3CH2),2 and [Os(η5-C9H7)-
(dCdCHR)(PPh3)2]PF6 (R ) H, (CH2)3CH2OH, tBu,
CdCH(CH2)nCH2).3 In contrast to osmium, the ruthe-
nium analogues are well known and have attracted
increasing attention in recent years, due to their con-
nection with important stoichiometric and catalytic
reactions of utility in organic synthesis.4
The procedure widely used in the preparation of
cationic half-sandwich ruthenium vinylidene complexes
involves the treatment of chloro starting materials with
terminal alkynes in the presence of NH4PF6, NaBPh4,
or related salts.5 From a mechanistic point of view, it
has been proposed that these reactions proceed via
(1) Pourreau, D. B.; Geoffroy, G. L.; Rheingold, A. L.; Geib, S. J .
Organometallics 1986, 5, 1337.
(2) Esteruelas, M. A.; Go´mez, A. V.; Lo´pez, A. M.; Oro, L. A.
Organometallics 1996, 15, 878.
(3) Gamasa, M. P.; Gimeno, J .; Go´nzalez-Cueva, M.; Lastra, E. J .
Chem. Soc., Dalton Trans. 1996, 2547.
(4) (a) Bruce, M. I. Chem. Rev. 1991, 91, 197. (b) Trost, B. M. Chem.
Ber. 1996, 129, 1313. (c) Naota, T.; Takaya, H.; Murahashi, S.-I. Chem.
Rev. 1998, 98, 2599. (d) Puerta, M. C.; Valerga, P. Coord. Chem. Rev.
1999, 193-195, 977. (e) Bruneau, C.; Dixneauf, P. H. Acc. Chem. Res.
1999, 32, 311. (f) Mitsudo, T.; Kondo, T. Synlett 2001, 309.
(5) See for example: (a) Lagadec, R. L.; Roman, E.; Toupet, L.;
Mu¨ller, U.; Dixneuf, P. H. Organometallics 1994, 13, 5030. (b) de los
R´ıos, I.; J ime´nez-Tenorio, M.; Puerta, M. C.; Valerga, P. J . Chem. Soc.,
Chem. Commun. 1995, 1757. (c) de los R´ıos, I.; J ime´nez-Tenorio, M.;
Puerta, M. C.; Valerga, P. J . Am. Chem. Soc. 1997, 119, 6529. (d)
Cadierno, V.; Gamasa, M. P.; Gimeno, J .; Pe´rez-Carren˜o, E.; Garc´ıa-
Granda, S. Organometallics 1999, 18, 2821. (e) Bustelo, E.; J ime´nez-
Tenorio, M.; Puerta, M. C.; Valerga, P. Organometallics 1999, 18, 950.
(f) Bustelo, E., J ime´nez-Tenorio, M.; Puerta, M. C.; Valerga, P.
Organometallics 1999, 18, 4563.
To understand the behavior of the osmium systems,
we have carried out ab initio calculations on the
model complexes [Os(η5-C5H5)(η2-HCtCH)(PH3)2]+ (1),
[OsH(η5-C5H5)(CtCH)(PH3)2]+ (2), and [Os(η5-C5H5)-
(6) Theoretical studies support both mechanisms. See for example:
(a) Silvestre, J .; Hoffmann, R. Helv. Chim. Acta 1985, 68, 1461. (b)
Wakatsuki, Y.; Koga, N.; Yamazaki, H.; Morokuma, K. J . Am. Chem.
Soc. 1994, 116, 8105. (c) Wakatsuki, Y.; Koga, N.; Werner, H.;
Morokuma, K. J . Am. Chem. Soc. 1997, 119, 360. (d) Stegman, R.;
Frenking, G. Organometallics 1998, 17, 2089.
(7) Esteruelas, M. A.; Lo´pez, A. M.; Ruiz, N.; Tolosa, J . I. Organo-
metallics 1997, 16, 4657.
(8) Baya, M.; Crochet, P.; Esteruelas, M. A.; Gutie´rrez-Puebla, E.;
Lo´pez, A. M.; Modrego, J .; On˜ate, E.; Vela, N. Organometallics 2000,
19, 2585.
10.1021/om0104565 CCC: $20.00 © 2001 American Chemical Society
Publication on Web 09/07/2001

4292 Organometallics, Vol. 20, No. 20, 2001
Notes
Sch em e 2
The theoretical calculations also indicate that the
vinylidene model complex 3 is 22.4 kcal‚mol-1 more
stable than 2. However, the complexes [OsH(η5-
C5H5)(CtCR)(PiPr3)2]+ do not evolve into the corre-
sponding vinylidenes in the solid state or in solution,
in contrast to that observed for the related hydride-
alkynyl-ruthenium(IV) compounds.5c,e,f
It has been proposed, according to Schemes 1 and 2,
that once the hydride-alkynyl intermediates are formed,
the hydride dissociates as a proton, yielding alkynyl
species. Protonation of these intermediates at the Câ
atom affords the vinylidene derivatives. As a conse-
quence of the common ion effect, it has been experi-
mentally proved that the addition of strong acids
inhibits the formation of the vinylidenes.5c The different
behavior observed for the hydride-alkynyl-ruthenium-
(IV) and -osmium(IV) suggests that the basicity of the
osmium species Os(η5-C5H5)(CtCR)(PiPr3)2 is higher
than that of the related ruthenium one. This agrees with
the well-known increase of the basicity of transition
metal complexes as the metal is replaced by successively
heavier metals from the same group.12 As a consequence
of the high basicity of the Os(η5-C5H5)(CtCR)(PiPr3)2
species, the necessary energy for the dissociation of H+
from [OsH(η5-C5H5)(CtCR)(PiPr3)2]+ imposes a high
activation barrier for the isomerization of the hydride-
alkynyl-osmium(IV) complexes into the corresponding
vinylidene derivatives.
F igu r e 1. Optimized structures and relative energies
(kcal‚mol-1) of [Os(η5-C5H5)(η2-HCtCH)(PH3)2]+ (1), [OsH-
(η5-C5H5)(CtCH)(PH3)2]+ (2), and [Os(η5-C5H5)(dCdCH2)-
(PH3)2]+ (3) obtained by ab initio calculations at the DFT/
B3LYP level using the LANL2DZ basis set and ECP for
Os and 6-31G for the rest of the atoms.
(dCdCH2)(PH3)2]+ (3). Figure 1 shows their optimized
structures and relative energies at the DFT/B3LYP
level.9 The results show that the π-alkyne model com-
plex 1 is 4.0 kcal‚mol-1 more stable than the hydride-
alkynyl model compound 2; that is, the π-alkyne species
[Os(η5-C5H5)(η2-HCtCR)(PR′3)2]+ cannot be intermedi-
ates in the formation of [OsH(η5-C5H5)(CtCR)(PR′3)2]+,
since they appear to be thermodynamically more stable
than the products of the oxidative addition. The fact
that the reactions of [Os(η5-C5H5)(PiPr3)2]+ with termi-
nal alkynes afford selectively [OsH(η5-C5H5)(CtCR)-
(PiPr3)2]+ must be rationalized assuming that the oxida-
tive addition of the H-C(sp) bond of the alkyne is a
kinetically favored process with regard to the coordina-
tion of the carbon-carbon triple bond.10 So, for osmium,
pathways a and b are not competitive processes on a
common intermediate but independent reactions with-
out any common intermediate (Scheme 2).
In agreement with the theoretical results and the
pathway b of Scheme 2, the vinylidene compounds of
the type [Os(η5-C5H5)(dCdCHR)(PiPr3)2]+ can be pre-
pared by deprotonation of [OsH(η5-C5H5)(CtCR)-
(PiPr3)2]+ with strong bases and subsequent protonation
of the resulting alkynyl-osmium(II) intermediates
(Scheme 3).
Treatment of the previously reported compounds
[OsH(η5-C5H5)(CtCR)(PiPr3)2]PF6 (R ) Cy (4), Ph (5))
with a 1:10 excess of KOH in methanol affords the
alkynyl derivatives Os(η5-C5H5)(CtCR)(PiPr3)2 (R ) Cy
(6), Ph (7)) in good yield, after 1 h at room temperature.
In the IR spectra of these compounds in Nujol, the most
noticeable feature is the presence of the ν(CtC) vibra-
tions, which appear at 2069 (6) and 2074 (7) cm-1. In
the 13C{1H} NMR spectra, the OsC(sp) resonances are
observed as triplets at 65.5 (6) and 93.1 (7) ppm with
C-P coupling constants of about 18 Hz, whereas the
(9) Frisch, M. J .; Trucks, G. W.; Schlegel, H. B.; Scuseria, G. E.;
Robb, M. A.; Cheeseman, J . R.; Zakrzewski, V. G.; Montgomery, J . A.,
J r.; Stratmann, R. E.; Burant, J . C.; Dapprich, S.; Millam, J . M.;
Daniels, A. D.; Kudin, K. N.; Strain, M. C.; Farkas, O.; Tomasi, J .;
Barone, V.; Cossi, M.; Cammi, R.; Mennucci, B.; Pomelli, C.; Adamo,
C.; Clifford, S.; Ochterski, J .; Petersson, G. A.; Ayala, P. Y.; Cui, Q.;
Morokuma, K.; Malick, D. K.; Rabuck, A. D.; Raghavachari, K.;
Foresman, J . B.; Cioslowski, J .; Ortiz, J . V.; Baboul, A. G.; Stefanov,
B. B.; Liu, G.; Liashenko, A.; Piskorz, P.; Komaromi, I.; Gomperts, R.;
Martin, R. L.; Fox, D. J .; Keith, T.; Al-Laham, M. A.; Peng, C. Y.;
Nanayakkara, A.; Gonzalez, C.; Challacombe, M.; Gill, P. M. W.;
J ohnson, B.; Chen, W.; Wong, M. W.; Andres, J . L.; Gonzalez, C.; Head-
Gordon, M.; Replogle, E. S.; Pople, J . A. Gaussian 98, Revision A.7;
Gaussian, Inc.: Pittsburgh, PA, 1998.
(10) We have previously reached the same conclusion in an intuitive
manner.8 In this context, it should be noted that the coordination of
the alkyne requires a parallel approach of the carbon-carbon triple
bond to the phosphorous-phosphorous vector, while the oxidative
addition of the alkyne should take place via a perpendicular approach
of the H-C(sp) bond to the P-P vector. Furthermore, a heterolytic
H-C activation of the alkyne cannot be discarded, due to the well-
known acidic character of the H-C(sp) hydrogen of the alkynes.11
(11) See for example: Esteruelas, M. A.; Lahoz, F. J .; Oliva´n, M.;
On˜ate, E.; Oro, L. A. Organometallics 1995, 14, 3486.
(12) (a) Angelici, R. J . Acc. Chem. Res. 1995, 28, 51. (b) Abdur-
Rashid, K.; Fong, T. P.; Greaves, B.; Gusev, D. G.; Hinman, J . G.;
Landau, S. E.; Lough, A. J .; Morris, R. H. J . Am. Chem. Soc. 2000,
122, 9155.

Notes
Organometallics, Vol. 20, No. 20, 2001 4293
Sch em e 3
Câ(sp) resonances appear as singlets at about 109 ppm.
The 31P{1H} NMR spectra show singlets at about 4 ppm.
According to Scheme 3, the addition of 1.0 equiv of
HPF6 in water to diethyl ether solutions of 6 and 7 leads
to the vinylidenes [Os(η5-C5H5)(dCdCHR)(PiPr3)2]PF6
F igu r e 2. Molecular diagram for the cation of [Os(η5-
C5H5)(dCdCHPh)(PiPr3)2]PF6 (9). Thermal ellipsoids are
shown at 50% probability. Selected bond lengths (Å) and
angles (deg): Os(1)-C(1) 1.793(8) and 1.794(8), C(1)-C(2)
1.337(10) and 1.346(10); P(1)-Os(1)-P(2) 102.52(7) and
101.54(7), P(1)-Os(1)-C(1) 96.3(2) and 95.5(2), P(2)-Os-
(1)-C(1) 89.0(3) and 93.7(2), Os(1)-C(1)-C(2) 166.7(7) and
171.1(7), C(1)-C(2)-C(3) 134.8(8) and 126.9(8).
1
(R ) Cy (8) Ph (9)) in high yields. The H NMR spectra
of these compounds show the dCH resonances of the
vinylidene ligands at 2.54 (8) and 2.79 (9) ppm. In the
13C{1H} NMR spectra the CR atoms of the vinylidenes
display triplets at 300.6 (8) and 307.1 (9) ppm with
coupling constants of 10.9 (8) and 12.0 (9) Hz, whereas
the resonances corresponding to the Câ atoms appear
as singlets at 119.3 (8) and 117.0 (9) ppm. The 31P{1H}
NMR spectra show singlets at 8.6 (8) and 9.3 (9) ppm.
Complex 9 has been further characterized by an X-ray
crystallographic study. The structure has two chemical
equivalent but crystallographically independent mol-
ecules of complex 9 in the asymmetric unit. A drawing
of one of them is shown in Figure 2. The geometry
around the osmium center is close to octahedral, with
the cyclopentadienyl ligand occupying three sites of a
face. The P(1)-Os-C(1) and P(2)-Os-C(1) angles are
96.3(2)° and 95.5(2)° and 89.0(3)° and 93.7(2)°, respec-
tively, while the P(1)-Os-P(2) angle (102.52(7)° and
101.54(7)°) strongly deviates from the ideal value of 90°.
This is due to the large steric hindrance experienced
by the triisopropylphosphine groups, as a consequence
of their large cone angle (160°).13 Similar values (be-
tween 102.7(1)° and 106.72(4)°) have been found in other
transition-metal compounds containing two bulky phos-
phines mutually cis disposed.8,14
the structures of 3 and 9 is the P-Os-P angle. The
calculated value (92.7°) is significantly lower than that
obtained from the X-ray diffraction analysis. This
indicates that, in fact, the deviation observed from the
ideal value of 90° in 9 is mainly due to the large steric
hindrance experienced by the triisopropylphosphine
groups. The same relationship has been previously
observed between the structures of the carbyne com-
pounds [Os(η5-C5H5)(tCCHdCH2)(PH3)2]2+ and [Os(η5-
C5H5)(tCCHdCPh2)(PiPr3)2]2+ 8
.
In summary, although similarly to ruthenium,5d the
cationic half-sandwich osmium vinylidene complexes
[Os(η5-C5H5)(dCdCHR)(PiPr3)2]+ are the thermody-
namically favored products from the reactions of [Os-
(η5-C5H5)(PiPr3)2]+ with terminal alkynes, they cannot
be obtained in a one-pot synthesis reaction because (i)
the oxidative addition of the H-C(sp) bond of the alkyne
is kinetically favored with regard to the coordination of
the carbon-carbon triple bond, and (ii) the high basicity
of the alkynyl intermediates Os(η5-C5H5)(CtCR)(PiPr3)2
imposes a high energy for the dissociation of H+ from
[OsH(η5-C5H5)(CtCR)(PiPr3)2]+, which is the rate-
determining step for the transformation of the hydride-
alkynyls into vinylidenes. Thus, the formation of the
vinylidenes [Os(η5-C5H5)(dCdCHR)(PiPr3)2]+ from [Os-
(η5-C5H5)(PiPr3)2]+ and terminal alkynes requires a
three-step procedure involving (i) oxidative addition of
the H-C(sp) bond of the alkyne to the metallic center
of the starting complex, (ii) deprotonation of the result-
ing hydride-alkynyl derivatives [OsH(η5-C5H5)(CtCR)-
(PiPr3)2]+ with strong bases, and (iii) protonation of the
resulting alkynyls Os(η5-C5H5)(CtCR)(PiPr3)2.
The vinylidene ligand is bound to the osmium in a
nearly linear fashion with Os-C(1)-C(2) angles of
166.7(7)° and 171.1(7)°. The Os-C(1) (1.793(8) and
1.794(8) Å) and C(1)-C(2) (1.337(10) and 1.346(10) Å)
bond lengths compare well with those found in other
osmium-vinylidene complexes15 and support the vi-
nylidene formulation.
The structural parameters of the model complex 3 are
in agreement with those obtained from the X-ray
diffraction analysis for 9. The main difference between
(13) Tolman, C. A. Chem. Rev. 1977, 77, 313.
(14) (a) Werner, H.; Scha¨fer, M.; Nu¨rnberg, O.; Wolf, J . Chem. Ber.
1994, 127, 27. (b) Esteruelas, M. A.; Lahoz, F. J .; On˜ate, E.; Oro, L.
A.; Rodr´ıguez, L.; Steinert, P.; Werner, H. Organometallics 1997, 16,
6010. (c) Buil, M. L.; Esteruelas, M. A.; Garc´ıa-Yebra, C.; Gutie´rrez-
Puebla, E.; Oliva´n, M. Organometallics 2000, 19, 2184.
(15) Castarlenas, R.; Esteruelas, M. A.; Gutie´rrez-Puebla, E.; On˜ate,
E. Organometallics 2001, 20, 1545.
Exp er im en ta l Section
All reactions were carried out with rigorous exclusion of air
using Schlenk-tube techniques. Solvents were dried by known

4294 Organometallics, Vol. 20, No. 20, 2001
Notes
procedures and distilled under argon prior to use. The starting
materials [OsH(η5-C5H5)(CtCR)(PiPr3)2]PF6 (R ) Cy (4), Ph
(5)) were prepared as previously reported.8
ether was added a solution of HPF6 (7 µL, 75% in water, 0.046
mmol). The resulting suspension was decanted, and the solid
was washed with diethyl ether (2 × 3 mL). A dark pink solid
was isolated. Yield: 29 mg (78%). Anal. Calcd for C31H53F6-
OsP3: C, 45.25; H, 6.49. Found: C, 45.68; H, 6.58. IR (Nujol,
cm-1): ν(CdC) 1622 (s), ν(PF6) 841 (s). 1H NMR (300 MHz,
CDCl3, 293 K): δ 7.40-6.90 (5 H, Ph), 5.83 (s, 5 H, Cp), 2.79
(br s, 1 H, OsdCdCH), 2.42 (m, 6 H, PCH), 1.26 (dvt, 18 H,
In the NMR spectra, chemical shifts are expressed in ppm
downfield from Me4Si (1H and 13C) and 85% H3PO4 (31P).
P r ep a r a tion of Os(η5-C5H5)(CtCCy)(P iP r 3)2 (6). A sus-
pension of 4 (105 mg, 0.13 mmol) in MeOH (10 mL) was treated
with an excess of KOH (70 mg, 1.25 mmol). After the mixture
was stirred for 2 h at room temperature, the resulting solution
was evaporated to dryness. The residue was extracted with
10 mL of toluene, and the filtrate was vacuum-dried. The pale
yellow oil was treated with 1 mL of cold pentane to afford a
white solid, which was dried in a vacuum. Yield: 44.6 mg
(52%). Anal. Calcd for C31H58OsP2: C, 55.00; H, 7.74. Found:
C, 54.90; H, 7.41. IR (Nujol, cm-1): ν(CtC) 2069 (m). 1H NMR
(300 MHz, C6D6, 293 K): δ 4.76 (s, 5 H, Cp), 2.94 (br t, 1 H,
3J HP ) 10.2 Hz, OsdCdCH), 2.39 (m, 6 H, PCH), 2.10-0.90
3
3J HH ) 7.2 Hz, N ) 13.5 Hz, PCHCH3), 1.22 (dvt, 18 H, J HH
) 7.2 Hz, N ) 13.5 Hz, PCHCH3). 13C{1H} NMR (75.5
2
MHz, CDCl3, 293 K, plus APT): δ 307.1 (-, t, J CP ) 12.0 Hz,
OsdCdC), 128.6, 127.8 (+, s, Cortho, Cmeta Ph), 126.4 (+, s, Cpara
Ph), 125.1 (-, s, Cipso Ph), 117.0 (+, s, OsdCdC), 86.8 (+, s,
Cp), 31.5 (+, second-order system, PCH), 20.6, 20.4 (+, s,
PCHCH3). 31P{1H} NMR (121.4 MHz, CDCl3, 293 K): δ 9.3 (s,
PiPr3), -144.1 (sept, J HH ) 714 Hz, PF6). MS (FAB+): m/z 679
(M+), 517 (M+ - PiPr3).
3
(11 H, Cy), 1.26 (dvt, 18 H, J HH ) 7.5 Hz, N ) 12.0 Hz,
X-r a y Str u ctu r e Deter m in a tion of 9. Crystals suitable
for the X-ray diffraction study were obtained by slow diffusion
of diethyl ether into a concentrated solution of 9 in dichlo-
romethane. Crystal data for [Os(η5-C5H5)(dCdCHPh)2(PiPr3)2]-
PF6 (9): C31H53F6OsP3 (MW ) 822.84); triclinic space group,
P1h; a ) 8.8234(5) Å, b ) 19.1665(11) Å, c ) 20.1403(11) Å, R
) 92.534(1)°, â ) 99.327(1)°, γ ) 91.696(1)° at 173.0(2); V )
3355.3(3) Å3; Z ) 4. An irregular crystal (0.12 × 0.02 × 0.02
mm) was mounted on a Bruker Smart APEX CCD diffracto-
meter equipped with a normal focus, 2.4 kW sealed tube X-ray
source (molybdenum radiation, λ ) 0.71073 Å) operating at
50 kV and 40 mA. Data were collected over the entire sphere
by a combination of four sets. The cell parameters were
determined and refined by least-squares fit of 3533 collected
reflections. Each frame exposure time was 30 s covering 0.3°
in ω (3° e 2θ e 60°, 41 672 reflections, 15 867 unique, merging
R factor 0.1136). The first 100 frames were collected at the
end of the data collection to monitor crystal decay. The
absorption correction was made using SADABS.16 The struc-
ture was solved by Patterson and Fourier methods using
SHELXS.16 Full matrix least-squares refinement was carried
3
PCHCH3); 1.16 (dvt, 18 H, J HH ) 7.5 Hz, N ) 12.0 Hz,
PCHCH3). 13C{1H} NMR (75.5 MHz, C6D6, 293 K): δ 109.1 (s,
tCCy); 74.6 (s, Cp), 65.5 (t, 2J CP ) 18.4 Hz, OsCt), 36.4, 33.8,
26.9, 26.2 (all s, Cy), 30.6 (second-order system, PCH), 21.6,
21.0 (s, PCHCH3). 31P{1H} NMR (121.4 MHz, C6D6, 293 K): δ
3.9 (s). MS (FAB+): m/z 685 (M+), 523 (M+ - PiPr3).
P r ep a r a tion of Os(η5-C5H5)(CtCP h )(P iP r 3)2 (7). Com-
plex 7 was prepared analogously as described for 6 starting
from 5 (110 mg, 0.13 mmol). Yield: 80 mg (75%). Anal. Calcd
for C31H52OsP2: C, 55.01; H, 7.71. Found: C, 54.79; H, 7.53.
1
IR (Nujol, cm-1): ν(CtC) 2074 (m). H NMR (300 MHz, C6D6,
293 K): δ 7.60-6.90 (5 H, Ph); 4.79 (s, 5 H, Cp), 2.36 (m, 6 H,
PCH), 1.23 (dvt, 18 H, 3J HH ) 7.1 Hz, N ) 11.7 Hz, PCHCH3),
3
1.11 (dvt, 18 H, J HH ) 7.1 Hz, N ) 11.7 Hz, PCHCH3). 13C-
{1H} NMR (75.5 MHz, C6D6, 293 K): δ 132.2, (s, Cipso Ph), 131.3
(s, Cpara Ph), 128.1, 122.7 (s, Cortho, Cmeta Ph), 109.9 (s, tCPh),
93.1 (t, 2J CP ) 18.5 Hz, OsCt), 75.1 (s, Cp), 30.4 (second-order
system, PCH), 21.2, 20.8 (s, PCHCH3). 31P{1H} NMR (121.4
MHz, C6D6, 293 K): δ 4.6 (s). MS (FAB+): m/z 679 (M+ + H).
P r ep a r a tion of [Os(η5-C5H5)(dCdCHCy)(P iP r 3)2]P F 6
(8). To a solution of 6 (58 mg, 0.084 mmol) in 6 mL of diethyl
ether was added a solution of HPF6 (12 µL, 75% in water, 0.083
mmol). The resulting suspension was decanted, and the solid
was washed with diethyl ether (2 × 4 mL). A pink solid was
isolated. Yield: 78 mg (80%). Anal. Calcd for C31H59F6OsP3:
C, 44.91; H, 7.19. Found: C, 44.51; H, 7.12. IR (Nujol, cm-1):
ν(CdC) 1651 (s), ν(PF6) 839 (s). 1H NMR (300 MHz, CDCl3,
out using SHELXL9716 minimizing w(Fo - Fc2)2. Weighted R
2
factors (Rw) and goodness of fit (S) are based on F2, conven-
tional R factors are based on F. Final R1 [F2 > 2σ(F2)] ) 0.0456,
wR2 [all data] ) 0.0796, and S [all data] ) 0.602.
Ack n ow led gm en t. We acknowledge financial sup-
port from the DGES of Spain (Project PB98-1591). M.B.
thanks the DGA (Diputacio´n General de Arago´n) for a
grant.
293 K): δ 5.68 (s, 5 H, Cp), 2.54 (m, 1 H, OsdCdCH), 2.36
3
(m, 6 H, PCH), 1.80-0.90 (11 H, Cy), 1.26 (dvt, 18 H, J HH
)
3
7.2 Hz, N ) 13.2 Hz, PCHCH3), 1.21 (dvt, 18 H, J HH ) 7.2
Hz, N ) 13.2 Hz, PCHCH3). 13C{1H} NMR (75.5 MHz, CDCl3,
Su p p or tin g In for m a tion Ava ila ble: Tables of atomic
coordinates, anisotropic and isotropic thermal parameters,
experimental details of the X-ray study, and bond distances
and angles for 9. This material is available via the Internet
at http://pubs.acs.org.
2
293 K, plus APT): δ 300.6 (-, t, J CP ) 10.9 Hz, OsdCdC),
119.3 (+, s, OsdCdC), 86.5 (+, s, Cp), 37.4, 26.2, 25.4 (-, s,
CH2 in Cy), 31.2 (+, second-order system, PCH), 29.9 (+, s,
CH in Cy), 20.3, 20.1 (+, s, PCHCH3). 31P{1H} NMR (121.4
MHz, CDCl3, 293 K): δ 8.6 (s, PiPr3), -145.2 (sept, J HH ) 714
Hz, PF6). MS (FAB+): m/z 685 (M+), 523 (M+ - PiPr3).
P r ep a r a tion of [Os(η5-C5H5)(dCdCHP h )(P iP r 3)2]P F 6
(9). To a solution of 7 (30.8 mg, 0.045 mmol) in 5 mL of diethyl
OM0104565
(16) SAINTPLUS and SHELXTL v. 6.1 software packages; Bruker
Analytical X-ray Systems, Madison, WI, 2000.