Reactions of elongated dihydrogen-osmium complexes containing orthometalated ketones with alkynes: Hydride-vinylidene-π-alkyne versus hydride-osmacyclopropene

Article abstract of DOI:10.1021/om021043m

In this paper, the preparation and characterization of new organometallic compounds, elongated dihydrogen complexes containing metal -σ carbon bonds allows access to highly unsaturated monohydride intermediates. The alkyne acting as the substituent R, res

Full text of DOI:10.1021/om021043m

2472
Organometallics 2003, 22, 2472-2485
Rea ction s of Elon ga ted Dih yd r ogen -Osm iu m Com p lexes
Con ta in in g Or th om eta la ted Keton es w ith Alk yn es:
Hyd r id e-Vin ylid en e-π-Alk yn e ver su s
Hyd r id e-Osm a cyclop r op en e
Pilar Barrio, Miguel A. Esteruelas,* 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 December 27, 2002
with terminal alkynes have played a predominant role.3
The trihydride complex OsH3{C6F4C(O)CH3}(PiPr3)2
(1) reacts with HBF4‚H2O to give the elongated dihy-
Until 1993, the observed products were in general
alkenyl derivatives, resulting of the addition of the M-H
bond to the C-C triple bond of the alkyne.4
drogen derivative [Os{C6F4C(O)CH3}(η2-H2)(H2O)(PiPr3)2]-
BF4 (2), with a separation between the hydrogen atoms
of the elongated dihydrogen of about 1.3 Å. Under one
atmosphere of acetylene, complex 2 and the related
In 1993, we observed that, in contrast to the general
trend, the dihydride-dichloro complex OsH2Cl2(PiPr3)2
reacts with terminal alkynes to afford hydride-carbyne
derivatives of the type OsHCl2(tCCH2R)(PiPr3)2.5 It was
proposed that the reason for this unusual finding was
the tendency shown by the starting dihydride to form
dihydrogen complexes.6 In subsequent years, we have
shown that the reactions of transition-metal hydride
complexes with terminal alkynes can afford a wide
range of organometallic compounds. The nature of the
products depends on all the factors related to the
[Os{C6H4C(O)CH3}(η2-H2)(H2O)(PiPr3)2]BF4 (3) afford
the hydride-vinylidene-π-alkyne derivative [OsH(dCd
CH2)(η2-HCtCH)(PiPr3)2]BF4 (4), with the alkyne acting
as a four-electron donor ligand. Complex 4 reacts with
methylmagnesium chloride and acetone oxime. The first
reaction gives the allyl derivative OsH(η3-C3H5)(dCd
CH2)(PiPr3)2 (5), whereas the second one affords the
oximate-carbyne [OsH{κ-N,κ-O[ONdC(CH3)2]}(tCCH3)-
(PiPr3)2]BF4 (6). Similarly to acetylene, cyclohexyl-
acetylene reacts with 2 and 3 to give [OsH(dCdCHCy)-
(η2-HCtCCy)(PiPr3)2]BF4 (7), which in solution at room
temperature decomposes to a mixture of unidentified
products. Complexes 2 and 3 also react with phenyl-
acetylene. The reactions lead to complex mixtures of
products containing [OsH(dCdCHPh)(η2-HCtCPh)-
(3) See for example: (a) Gru¨nwald, C.; Gevert, O.; Wolf, J .; Gonza´lez-
Herrero, P.; Werner, H. Organometallics 1996, 15, 1960. (b) Wilhelm,
T. E.; Belderrain, T. R.; Brown, S. N.; Grubbs, R. H. Organometallics
1997, 16, 3867. (c) Wolf, J .; Stu¨er, W.; Gru¨nwald, C.; Gevert, O.;
Laubender, M.; Werner, H. Eur. J . Inorg. Chem. 1998, 1827. (d) Wolf,
J .; Stu¨er, W.; Gru¨nwald, C.; Werner, H.; Schwab, P.; Schulz, M. Angew.
Chem., Int. Ed. 1998, 37, 1124. (e) Stu¨er, W.; Wolf, J .; Werner, H.;
Schwab, P.; Schulz, M. Angew. Chem., Int. Ed. 1998, 37, 3421. (f)
Huang, D.; Oliva´n, M.; Huffman, J . C.; Eisenstein, O.; Caulton, K. G.
Organometallics 1998, 17, 4700. (g) Yasuda, T.; Fukuoka, A.; Hirano,
M.; Komiya, S. Chem. Lett. 1998, 29. (h) Lough, A. J .; Morris, R. H.;
Ricciuto, L.; Schleis, T. Inorg. Chim. Acta 1998, 270, 238. (i) Xia, H.
P.; Yeung, R. C. Y.; J ia, G. Organometallics 1998, 17, 4762. (j) Werner,
H.; J ung, S.; Weberndo¨rfer, B.; Wolf, J . Eur. J . Inorg. Chem. 1999,
951. (k) Mulford, D. R.; Clark, J . R.; Schweiger, S. W.; Fanwick, P. E.;
Rothwell, I. P. Organometallics 1999, 18, 4448. (l) Yi, C. S.; Lee,
D. W.; Chen, Y. Organometallics 1999, 18, 2043. (m) Tsai, Y.-C.;
Diaconescu, P. L.; Cummins, C. C. Organometallics 2000, 19, 5260.
(n) Wen, T. B.; Zhou, Z. Y.; Lau, C.-P.; J ia, G. Organometallics 2000,
19, 3466. (o) Yang, S. Y.; Wen, T. B.; J ia, G.; Lin, Z. Organometallics
2000, 19, 5477. (p) Yao, J .; Wong, W. T.; J ia, G. J . Organomet. Chem.
2000, 598, 228. (q) Cabeza, J . A.; Grepioni, F.; Llamazares, A.; Riera,
V.; Trivedi, R. Eur. J . Inorg. Chem. 2000, 1693. (r) Albertin, G.;
Antoniutti, S.; Bordignon, E.; Pegoraro, M. J . Chem. Soc., Dalton Trans.
2000, 3575. (s) Ara, I.; Berenguer, J . R.; Eguiza´bal, E.; Fornie´s, J .;
Go´mez, J .; Lalinde, E.; Sa´ez-Rocher, J . M. Organometallics 2000, 19,
4385. (t) Trebbe, R.; Schager, F.; Goddard, R.; Po¨rschke, K.-R. Organo-
metallics 2000, 19, 521. (u) Cabeza, J . A.; Grepioni, F.; Moreno, M.;
Riera, V. Organometallics 2000, 19, 5424. (v) Selmeczy, A. D.; J ones,
W. D. Inorg. Chim. Acta 2000, 300-302, 138. (w) Marchenko, A. V.;
Ge´rard, H.; Eisenstein, O.; Caulton, K. G. New J . Chem. 2001, 25, 1244.
(x) O’Connor, J . M.; Closson, A.; Hiibner, K.; Merwin, R.; Gantzel, P.;
Roddick, D. M. Organometallics 2001, 20, 3710. (y) Esteruelas, M. A.;
Herrero, J .; Lo´pez, A. M.; Oliva´n, M. Organometallics 2001, 20, 3202.
(z) Rourke, J . P.; Stringer, G.; Chow, P.; Deeth, R. J .; Yufit, D. S.;
Howard, J . A. K.; Marder, T. B. Organometallics 2002, 21, 429.
(4) Crabtree, R. H. The Organometallic Chemistry of the Transition
Metals; J . Wiley and Sons: New York, 1988; Chapter 7, pp 142-162.
(5) Espuelas, J .; Esteruelas, M. A.; Lahoz, F. J .; Oro, L. A.; Ruiz, N.
J . Am. Chem. Soc. 1993, 115, 4683.
(PiPr3)2]BF4 (8) and [OsH{C6X4C(O)CH3}{C(Ph)CH2}-
(PiPr3)2]BF4 (X ) F (9), H (11)), as main components.
In solution at room temperature, complex 8 evolves into
the diphenylbutadiene derivative [OsH(η4-C4H4Ph2){[η2-
CH2dC(CH3)]PiPr2}(PiPr2nPr)]BF4 (10). Complex 11
reacts with acetophenone to afford [OsH{C6H4C(O)-
CH3}2(PiPr3)2]BF4 (12). The X-ray structures of 4, 9, and
10 are also reported.
In tr od u ction
The 1984 Kubas report of the molecular hydrogen
complex1 has revived the interest in the organometallic
chemistry of the transition-metal hydride complexes,
during the last years.2 Within this field, the reactions
* Corresponding author. E-mail: maester@posta.unizar.es. Fax: 34
976761187.
(1) Kubas, G. J .; Ryan, R. R.; Swanson, B. I.; Vergamini, P. J .;
Wasserman, H. J . J . Am. Chem. Soc. 1984, 106, 451.
(2) (a) Kubas, G. J . Metal Dihydrogen and σ-Bond Complexes;
Kluwer Academic/Plenum Publishers: New York, 2001. (b) Peruzzini,
M.; Poli, R. Recent Advances in Hydride Chemistry; Elsevier: Amster-
dam, 2001.
(6) (a) Esteruelas, M. A.; Oro, L. A.; Ruiz, N. Inorg. Chem. 1993,
32, 3793. (b) Esteruelas, M. A.; Lahoz, F. J .; Oro, L. A.; On˜ate, E.;
Ruiz, N. Inorg. Chem. 1994, 33, 787. (c) Barea, G.; Esteruelas, M. A.;
Lledo´s, A.; Lo´pez, A. M.; Tolosa, J . I. Inorg. Chem. 1998, 37, 5033.
10.1021/om021043m CCC: $25.00 © 2003 American Chemical Society
Publication on Web 05/07/2003

Elongated Dihydrogen-Osmium Complexes
Organometallics, Vol. 22, No. 12, 2003 2473
electronic structure of the starting material and even
on the electronic nature of the substituent, R, of the
alkyne.7
coupling. Our interest in the use of osmium complexes
as templates to carbon-carbon and carbon-heteroatom
coupling reactions prompted us to eliminate the inter-
ference of the oxime, and our interest in learning to
rationalize the reactivity of the hydride complex toward
alkynes prompted us to investigate the behavior of the
The electronic structure of the starting material has
a marked influence on the interactions within the M-H2
units. The character of the dihydride, elongated dihy-
drogen, or dihydrogen seems to determine the nature
of the product. For example, in contrast to the dihydride
OsH2Cl2(PiPr3)2, the elongated dihydrogen OsCl2(η2-H2)-
(CO)(PiPr3)2 reacts with terminal alkynes to give car-
bene derivatives of the type OsCl2(dCHCH2R)(CO)-
(PiPr3)2,8 while the reaction of the ruthenium dihydrogen
water complex Os{C6H4C(O)CH3}(η2-H2)(H2O)(PiPr3)2]-
BF4 in the presence of acetylene, cyclohexylacetylene,
and phenylacetylene. Furthermore, to know the influ-
ence of the substituents of the metalated phenyl ring
of the ketone on the stability of the starting complex
and the resulting products, we have prepared the
complex
[Ru(η5-C5H5)(η2-H2)(CO)(PiPr3)2]+
with
1,1-diphenyl-2-propyn-1-ol affords the allenylidene
[Ru(η5-C5H5)(dCdCdCPh2)(CO)(PiPr3)]+ via a hydroxy-
vinylidene intermediate.9
The character of the MH2 units is not the sole factor
determining the nature of the products. We have
recently reported that, in contrast to OsCl2(η2-H2)(CO)-
related elongated dihydrogen complex [Os{C6F4C(O)-
CH3}(η2-H2)(H2O)(PiPr3)2]BF4, and we have studied its
reactivity toward the above-mentioned alkynes.
In this paper, we show (i) new reactions, (ii) the
preparation and characterization of new organometallic
compounds, (iii) the influence of the steric hindrance of
the substituent, R, of the alkyne on the stability of the
obtained complexes, and (iv) the characterization of
some of the decomposition products from the latter
species.
(PiPr3)2, the cationic elongated dihydrogen [Os{C6H4C(O)-
CH3}(η2-H2){N(OH)dC(CH3)2}(PiPr3)2]+ reacts with ter-
minal alkynes to give the hydride-carbyne derivatives
[OsH{κ-N,κ-O[ONdC(CH3)2]}(tCCH2R)(PiPr3)2]+, re-
lated to those obtained with OsH2Cl2(PiPr3)2. Deuterium
labeling experiments indicate that these reactions in-
volve the initial elimination of acetophenone. The
transformation alkyne-carbyne occurs, via a hydride-
π-alkyne intermediate, in two dissociation-addition
processes, where the oxime plays a main role.10
Osmium-hydride complexes have shown to be useful
templates to carbon-carbon and carbon-heteroatom
coupling reactions.11 In the absence of oxime, the
elimination of the ketone should provide a highly
unsaturated system, which could coordinate several
alkyne molecules, the first step for their subsequent
Resu lts a n d Discu ssion
1. P r ep a r a t ion a n d Ch a r a ct er iza t ion of
[Os{C6F 4C(O)CH3}(η2-H2)(H2O)(P iP r 3)2]BF 4. Treat-
ment at room temperature of the trihydride
OsH3{C6F4C(O)CH3}(PiPr3)2 (1) in dichloromethane with
1.2 equiv of HBF4‚H2O affords the cationic elongated
dihydrogen derivative Os{C6F4C(O)CH3}(η2-H2)(H2O)-
(PiPr3)2]BF4 (2), as a result of the protonation of one of
the hydride ligands of 1 and the coordination of the
water molecule. Complex 2 was isolated as an orange
solid in 82% yield, according to eq 1.
(7) (a) Espuelas, J .; Esteruelas, M. A.; Lahoz, F. J .; Oro, L. A.; Valero,
C. Organometallics 1993, 12, 663. (b) Esteruelas, M. A.; Lahoz, F. J .;
On˜ate, E.; Oro, L. A.; Zeier, B. Organometallics 1994, 13, 1662. (c)
Esteruelas, M. A.; Oro, L. A.; Ruiz, N. Organometallics 1994, 13, 1507.
(d) Esteruelas, M. A.; Lahoz, F. J .; On˜ate, E.; Oro, L. A.; Zeier, B.
Organometallics 1994, 13, 4258. (e) Esteruelas, M. A.; Oro, L. A.;
Valero, C. Organometallics 1995, 14, 3596. (f) Esteruelas, M. A.; Oliva´n,
M.; Oro, L. A. Organometallics 1996, 15, 814. (g) Esteruelas, M. A.;
Lahoz, F. J .; On˜ate, E.; Oro, L. A.; Rodriguez, L. Organometallics 1996,
15, 3670. (h) Bourgault, M.; Castillo, A.; Esteruelas, M. A.; On˜ate, E.;
Ruiz, N. Organometallics 1997, 16, 636. (i) Edwards, A. J .; Elipe, S.;
Esteruelas, M. A.; Lahoz, F. J .; Oro, L. A.; Valero, C. Organometallics
1997, 16, 3828. (j) Buil, M. L.; Elipe, S.; Esteruelas, M. A.; On˜ate, E.;
Peinado, E.; Ruiz, N. Organometallics 1997, 16, 5748. (k) Bohanna,
C.; Callejas, B.; Edwards, A. J .; Esteruelas, M. A.; Lahoz, F. J .; Oro,
L. A.; Ruiz, N.; Valero, C. Organometallics 1998, 17, 373. (l) Crochet,
P.; Esteruelas, M. A.; Lo´pez, A. M.; Mart´ınez, M.-P.; Oliva´n, M.; On˜ate,
E.; Ruiz, N. Organometallics 1998, 17, 4500. (m) Buil, M. L.; Eisenstein,
O.; Esteruelas, M. A.; Garc´ıa-Yebra, C.; Gutie´rrez-Puebla, E.; Oliva´n,
M.; On˜ate, E.; Ruiz, M.; Tajada, M. A. Organometallics 1999, 18, 4949.
(n) Buil, M. L.; Esteruelas, M. A. Organometallics 1999, 18, 1798. (o)
Esteruelas, M. A.; Garc´ıa-Yebra, C.; Oliva´n, M.; On˜ate, E.; Tajada, M.
A. Organometallics 2000, 19, 5098. (p) Buil, M. L.; Esteruelas, M. A.;
Garc´ıa-Yebra, C.; Gutie´rrez-Puebla, E.; Oliva´n, M. Organometallics
2000, 19, 2184. (q) Castarlenas, R.; Esteruelas, M. A.; On˜ate, E.
Organometallics 2000, 19, 5454. (r) Castarlenas, R.; Esteruelas, M.
A.; On˜ate, E. Organometallics 2001, 20, 3283.
The presence of the water ligand in 2 is strongly
supported by its IR and 1H NMR spectra. The IR
spectrum in KBr shows a strong ν(OH) band at
(8) Esteruelas, M. A.; Lahoz, F. J .; On˜ate, E.; Oro, L. A.; Valero, C.;
Zeier, B. J . Am. Chem. Soc. 1995, 117, 7935.
1
3362 cm-1, whereas the H NMR spectrum in dichloro-
methane-d2 contains a broad singlet at 4.38 ppm,
characteristic of a coordinated water molecule. In the
high-field region of the spectrum, the hydrogen atoms
bonded to the metal display a triplet at -6.63 ppm with
a H-P coupling constant of 8.4 Hz. A variable-temper-
ature 300 MHz T1 study of this peak gives a T1(min) of
40 ( 1 ms at 213 K. The treatment of 2 with methanol-
(9) Esteruelas, M. A.; Go´mez, A. V.; Lahoz, F. J .; Lo´pez, A. M.;
On˜ate, E.; Oro, L. A. Organometallics 1996, 15, 3423.
(10) Barrio, P.; Esteruelas, M. A.; On˜ate, E. Organometallics 2002,
21, 2491.
(11) Esteruelas, M. A.; Lo´pez, A. M. Ruthenium- and Osmium-
hydride compounds containing triisopropylphosphine as precursor for
carbon-carbon and carbon-heteroatom coupling reactions. Recent
Advances in Hydride Chemistry; Elsevier: Amsterdam, 2001; Chapter
7, pp 189-248.

2474 Organometallics, Vol. 22, No. 12, 2003
Barrio et al.
Ta ble 1. Selected Bon d Dista n ces (Å) a n d
An gles (d eg) for th e Com p lex [OsH(dCdCH2)-
(η2-C2H2)(P iP r 3)2]BF 4 (4)
Os-P(1)
Os-P(2)
Os-C(1)
Os-C(3)
Os-C(4)
2.398(2)
2.400(2)
1.774(8)
2.022(10)
2.035(10)
C(1)-C(2)
C(3)-C(4)
1.320(13)
1.230(12)
P(1)-Os-P(2)
P(1)-Os-C(1)
P(1)-Os-Ma
155.39(7)
C(1)-Os-Ma
124.3(4)
95.0(18)
139(2)
169.7(9)
72.9(7)
71.8(7)
87.8(2)
101.2(3)
90.3(19)
87.7(2)
101.3(3)
66.0(19)
C(1)-Os-H(01)
M-Os-H(01)a
Os-C(1)-C(2)
Os-C(3)-C(4)
Os-C(4)-C(3)
P(1)-Os-H(01)
P(2)-Os-C(1)
P(2)-Os-Ma
P(2)-Os-H(01)
a
M is the midpoint of the C(3)-C(4) bond.
cation of 4. Selected bond distances and angles are listed
in Table 1.
F igu r e 1. Molecular diagram of the cation of complex
[OsH(dCdCH2)(η2-HCtCH)(PiPr3)2]BF4 (4).
The geometry around the osmium atom can be
described as a distorted trigonal bipyramid with apical
phosphines (P(1)-Os-P(2) ) 155.39(7)°) and inequiva-
lent angles within the Y-shaped equatorial plane
(H(01)-Os-M ) 139(2)°, H(01)-Os-C(1) ) 95.0(14)°,
and C(1)-Os-M ) 124.3(4)°).13 The strong deviation
of the P(1)-Os-P(2) angle from the ideal value of
180° is most probably a result of the large steric
hindrance that occurs between the phosphines and the
alkyne. The acetylene lies parallel to the phosphorus-
phosphorus vector; the angle between the P(1)-P(2)
and C(3)-C(4) vectors is 0.9°.
d4-water-d2 yields the partially deuterated derivative
[Os{C6F4C(O)CH3}(η2-HD)(D2O)(PiPr3)2]BF4, which has
a H-D coupling constant of 3.3 Hz. The T1(min) and
J (H-D) values suggest that the separation between
the hydrogen atoms of the dihydrogen ligand is about
1.3 Å.12
2. Rea ction s of [Os{C6X4C(O)CH3}(η2-H2)(H2O)-
(P iP r 3)2]BF 4 (X ) F , H) w ith Acetylen e a n d Cyclo-
h exyla cetylen e. In dichloromethane, under 1 atm of
The alkyne coordinates to the osmium atom in a
symmetrical fashion with statistically identical Os-C
bond lengths of 2.022(10) Å (Os-C(3)) and 2.035(10) Å
(Os-C(4)). The coordination does not produce any
significant disturbance on the carbon-carbon triple
bond. The C(3)-C(4) distance (1.230(12) Å) is statisti-
cally identical with the carbon-carbon distance deter-
mined for the free acetylene (1.212 Å) by electron
diffraction.14
acetylene, complexes 2 and [Os{C6H4C(O)CH3}(η2-H2)-
(H2O)(PiPr3)2]BF4 (3) eliminate the corresponding ke-
tones. The resulting unsaturated metallic fragment
coordinates two acetylene molecules to afford the hy-
dride-vinylidene-π-alkyne derivative [OsH(dCdCH2)-
(η2-HCtCH)(PiPr3)2]BF4 (4), which was isolated as a
yellow solid in about 70% yield, according to eq 2.
It has been shown that for five-coordinate complexes
an X ligand with σ-donating and good π-acceptor
capabilities favors a square-pyramidal structure with
the X ligand trans to the empty site. In contrast, an X
ligand with σ- and π-donating capabilities stabilizes the
trigonal bipyramid, with the X ligand in the foot of the
Y.15
At first glance, the chemical bonding in transition-
metal alkyne complexes can be described in a way
similar to that for transition-metal alkene compounds.
The bonding is considered to arise from donor-acceptor
interactions between the alkyne ligand and the transi-
tion metal (a and b in Figure 2). So, in principle, one
should expect for 4 a square-pyramidal arrangement of
ligands around the osmium atom, in contrast of that
observed in Figure 1.
A major difference between alkene and alkyne com-
plexes is that the alkyne ligand has a second occupied
π orbital orthogonal to the MC2 plane (π ) which, in
some cases, engages in the transition-metal-alkyne
bonding (c in Figure 2). In that case, the alkyne is a
Complex 4 is notable, not only because it is an isolated
rare example of a five-coordinate cationic hydride-
vinylidene compound but also because, as far as we
know, species containing at the same time hydride,
vinylidene, and π-acetylene ligands are not known.
Figure 1 shows a view of the molecular geometry of the
(12) (a) Earl, K. A.; J ia, G.; Maltby, P. A.; Morris, R. H. J . Am. Chem.
Soc. 1991, 113, 3027. (b) Desrosiers, P. J .; Cai, L.; Lin, Z.; Richards,
R.; Halpen, J . J . Am. Chem. Soc. 1991, 113, 4173. (c) J essop, P. G.;
Morris, R. H. Coord. Chem. Rev. 1992, 121, 155. (d) Maltby, P. A.;
Schlaf, M.; Steinbeck, M.; Lough, A. J .; Morris, R. H.; Klooster, W. T.;
Koetzle, T. F.; Srivastava, R. C. J . Am. Chem. Soc. 1996, 118, 5396.
(13) M ) midpoint of the C(3)-C(4) bond.
(14) Simonetta, M.; Gavezzotti, A. In The Chemistry of the Carbon-
Carbon Triple Bond; Patai, S., Ed.; Wiley and Sons: Chichester, 1978;
Chapter 1.
(15) Riehl, J .-F.; J ean, Y.; Eisenstein, O.; Pe´lissier, M. Organo-
metallics 1992, 11, 729.

Elongated Dihydrogen-Osmium Complexes
Organometallics, Vol. 22, No. 12, 2003 2475
observed for the two-electron-donor alkynes of the
complexes Os(η5-C5H5)Cl(η2-HCtCR)(PiPr3) (δ, 4.32
(C(OH)Ph2) and δ, 3.72 (C(OH)Me2)).16 A similar rela-
tionship is observed between 13C{1H} NMR spectra of
these compounds. For 4 the acetylenic resonance is
observed at 137.3 ppm, in agreement with the chemical
shifts observed for the cationic cyclopentadienyl com-
plexes (δ, 179.0 and 182.8 (tCR) and δ, 146.0 and 143.3
(tCH)). They are strongly shifted toward lower field
with respect to those found for the neutral cyclopenta-
dienyl derivatives (δ, 82.2 and 69.1 (tCR) and δ, 57.5
and 49.6 (tCH)).
F igu r e 2. Schematic representation of the donative (a and
c) and back-donative (b) interactions for metal-alkyne
bonding in complex 4.
The vinylidene ligand is bound to the metal in the
usual manner, with the CH2 unit lying in the equatorial
plane. A slight bending in the Os-C(1)-C(2) moiety is
present (Os-C(1)-C(2) ) 169.7(9)°). The Os-C(1)
(1.774(8) Å) and C(1)-C(2) (1.320(13) Å) bond lengths
compare well with those found in other osmium-
vinylidene complexes21 and support the vinylidene
formulation.
four-electron-donor ligand by means of its π| and π
orbitals; that is, in some cases the alkyne acts as σ- and
π-donor. The structure shown in Figure 1 suggests that
4 is one of these cases.
The alkyne acts as an electron acceptor by means of
its π* orbitals, as is supported by the IR spectra of 4 in
KBr showing a ν(CtC) band at 1882 cm-1. The π *
orbital is, however, of local a2 symmetry (within the C2v
group), which prevents it from significant interaction
with the filled d metal orbital. The only significant
interaction involves the acceptor orbital lying in the MC2
plane (π|* of local b1 symmetry).16
The trigonal bipyramid geometry of 4 agrees well
with that found in the oximate-vinylidene complex OsH-
{κ-N,κ-O[ONdC(CH3)2]}(dCdCHPh)(PiPr3)2 and the
10
calculated one for RuHCl(dCdCH2)(PH3)2.22 To explain
this finding, it has been argued that the vinylidenes are
also weak π-donor ligands in the orthogonal plane to
the CR2 plane. The donating properties of πCC disfavor
a trans relationship of the π-donor and vinylidene
ligands since this maximizes the overlaps between the
occupied orbitals of the metal and the two ligands.22,23
In the 1H NMR spectrum of 4, the protons of the
vinylidene display only one resonance at 1.70 ppm,
which appears as a triplet with a H-P coupling constant
of 4.5 Hz. The resonance is temperature-invariant
between 298 and 193 K. This suggests that the vi-
nylidene rotation is rapid on the NMR time scale. In
this context, it should be mentioned that Caulton and
co-workers have calculated an electronic barrier of
4.6 kcal‚mol-1 for the vinylidene rotation in RuHCl-
(dCdCH2)(PH3)2.22 In the 13C{1H} NMR spectrum,
the characteristic resonances of the vinylidene ligand
are observed at 283.6 (CR) and 90.3 (Câ) ppm. Both
resonances appear as a triplet with C-P coupling
constants of 14.8 and 6.0 Hz, respectively.
The chemistry of four-electron-donating alkynes has
been centered at early transition metals, mainly mo-
lybdenum and tungsten. A wide variety of six-coordinate
Mo(II) and W(II) complexes with four-electron-donor
alkynes have been synthesized.17 Four-coordinate d6
19
complexes of the types ML(alkyne)318 and ML2(alkyne)2
have been also reported. In contrast, five-coordinate d6
monoalkyne complexes with the general formula ML4-
(alkyne)20 are very scarce. Recently, we have prepared
the osmium-cyclopentadienyl derivatives [Os(η5-C5H5)-
(η2-HCtCR)(PiPr3)]PF6 (R ) C(OH)Ph2, C(OH)Me2).16
1
In the H NMR spectrum of 4 in dichloromethane-d2
at room temperature, the resonance corresponding to
the protons of the alkyne appears at 10.17 ppm as the
AA′ part of an AA′XX′ spin system. The chemical shift
of this resonance agrees well with those found for the
cyclopentadienyl complexes [Os(η5-C5H5)(η2-HCtCR)-
(PiPr3)]PF6 (δ, 9.43 (R ) C(OH)Ph2) and δ, 9.17 (R )
C(OH)Me2)), where the alkynes also act as four-electron-
donor ligands. These resonances appear strongly shifted
toward lower field with respect to the HCt resonances
The presence of a hydride ligand in 4 is strongly
1
supported by the IR and H NMR spectra. In addition
to the ν(CtC) band, the IR spectrum contains a
ν(Os-H) absorption at 2161 cm-1 along with that due
to the [BF4]- anion with Td symmetry, centered at about
1050 cm-1, in agreement with the salt character of the
complex. In the high-field region, the 1H NMR spectrum
contains a triplet at -3.58 ppm with a H-P coupling
constant of 22.9 Hz. The 31P{1H} NMR spectrum
contains a singlet at 30.8 ppm.
(16) Carbo´, J . J .; Crochet, P.; Esteruelas, M. A.; J ean, Y.; Lledo´s,
A.; Lo´pez, A. M.; On˜ate, E. Organometallics 2002, 21, 305.
(17) See for example: (a) Templeton, J . L. Adv. Organomet. Chem.
1989, 29, 1. (b) Baker, P. K. Adv. Organomet. Chem. 1996, 40, 45. (c)
Frohnapfel, D. S.; Reinartz, S.; White, P. S.; Templeton, J . L. Organo-
metallics 1998, 17, 3759. (d) Frohnapfel, D. S.; Enriquez, A. E.;
Templeton, J . L. Organometallics 2000, 19, 221.
(18) See for example: (a) Tate, D. P.; Augl, J . M. J . Am. Chem. Soc.
1963, 85, 2174. (b) Wink, D. J .; Creagan, T. Organometallics 1990, 9,
328. (c) Szyma´nska-Buzar, T.; Glowiak, T. J . Organomet. Chem. 1994,
467, 223. (d) Yeh, W.-Y.; Ting, C.-S. Organometallics 1995, 14, 1417.
(e) Mealli, C.; Masi, D.; Galindo, A.; Pastor, A. J . Organomet. Chem.
1998, 569, 21.
Complex 4 reacts with methylmagnesium chloride
and acetone oxime (Scheme 1). Treatment at room
temperature of 4 in tetrahydrofuran with 1.2 equiv of
(19) See for example: (a) Do¨tz, K. H.; Mu¨hlemeier, J . Angew. Chem.,
Int. Ed. Engl. 1982, 21, 929. (b) Salt, J . E.; Girolami, G. S.; Wilkinson,
G.; Motevalli, M.; Thornton-Pett, M.; Hursthouse, M. B. J . Chem. Soc.,
Dalton Trans. 1985, 685. (c) Wink, D. J .; Fox, J . R.; Cooper, N. J . J .
Am. Chem. Soc. 1985, 107, 5012.
(20) (a) Wink, D. J .; Creagan, B. T. J . Am. Chem. Soc. 1990, 112,
8585. (b) Pearson, J .; Cooke, J .; Takats, J .; J ordan, R. B. J . Am. Chem.
Soc. 1998, 120, 1434. (c) Mao, T.; Zhang, Z.; Washington, J .; Takats,
J .; J ordan, R. B. Organometallics 1999, 18, 2331. (d) Ishino, H.;
Kuwata, S.; Ishii, Y.; Hidai, M. Organometallics 2001, 20, 13.
(21) Castarlenas, R.; Esteruelas, M. A.; Gutie´rrez-Puebla, E.; On˜ate,
E. Organometallics 2001, 20, 1545, and references therein.
(22) Oliva´n, M.; Eisenstein, O.; Caulton, K. G. Organometallics 1997,
16, 2227.
(23) (a) Poulton, J . T.; Sigalas, M. P.; Folting, K.; Streib, W. E.;
Eisenstein, O.; Caulton, K. G. Inorg. Chem. 1994, 33, 1476. (b) Oliva´n,
M.; Clot, E.; Eisenstein, O.; Caulton, K. G. Organometallics 1998, 17,
3091. (c) Esteruelas, M. A.; Oro, L. A. Adv. Organomet. Chem. 2001,
47, 1, and references in therein.

2476 Organometallics, Vol. 22, No. 12, 2003
Barrio et al.
Sch em e 1
oxime to the Câ atom of the vinylidene and the displace-
ment of the π-alkyne by the resulting oximate group. It
is another member of the [OsH{κ-N,κ-O[ONdC(CH3)2]}-
(tCCH2R)(PiPr3)2]BF4 series. In a manner similar to
these compounds, it can also be prepared, in high yield
(about 80%), by reaction of the oxime elongated dihy-
drogen complex [Os{C6H4C(O)CH3}(η2-H2){N(OH)d
C(CH3)2}(PiPr3)2]BF4 with acetylene or alternatively
with trimethylsilylacetylene.
The most noticeable feature in the 1H NMR spectrum
of 6 in dichloromethane-d2 is the presence of three
singlets in the low-field region of the spectrum, at 2.25
and 2.18 (NdC(CH3)2) and 1.41 (CCH3) ppm. The
resonance corresponding to the hydride ligand appears
at -6.81 ppm, as a triplet with a H-P coupling constant
of 17.1 Hz. In the 13C{1H} NMR spectrum, the carbyne
ligand gives rise to a triplet at 283.8 (J C-P ) 9.4 Hz)
ppm corresponding to the CR atom and a singlet at 40.2
ppm due to the Câ atom. The 31P{1H} NMR spectrum
contains a singlet at 37.2 ppm.
At 233 K, cyclohexylacetylene reacts in a manner
similar to acetylene. At this temperature, the addition
of 2.0 equiv of the alkyne to the dichloromethane
solution of 2 or 3 affords the hydride-vinylidene-π-
alkyne complex [OsH(dCdCHCy)(η2-HCtCCy)(PiPr3)2]-
BF4 (7) and the corresponding ketone. Complex 7 was
isolated as a brown oil in about 55% yield, according to
eq 3.
MeMgCl leads to the allyl derivative OsH(η3-C3H5)(dCd
CH2)(PiPr3)2 (5), whereas the addition of 2.4 equiv of
acetone oxime to the dichloromethane solutions of 4
affords oximate-carbyne compound [OsH{κ-N,κ-O[ONd
C(CH3)2]}(tCCH3)(PiPr3)2]BF4 (6).
Complex 5 was isolated as a red oil in 91% yield.
Formally, it is the result of the addition of a methyl
group to the four-electron alkyne ligand. This addition
should afford an alkenyl intermediate, which could
isomerize into the allyl, via a π-allene species.24
The presence of an allyl ligand in 5 is strongly
1
supported by the H and 13C{1H} NMR spectra of this
1
compound. In the H NMR spectrum in benzene-d6, the
allyl ligand gives rise to five resonances at 4.92 (CH),
3.01 (Hsyn), 2.89 (Hanti), 2.16 (Hsyn), and 1.46 (Hanti) ppm,
with H-Hsyn and H-Hanti coupling constants of 6.9 and
10.2 Hz, respectively. The resonance corresponding to
the hydride ligand appears at -9.33 ppm, as a double
doublet of doublets with H-P coupling constants of 24.6
and 17.1 Hz and a H-Hanti coupling constant smaller
than 1.0 Hz. In the 13C{1H} NMR spectrum the allyl
ligand displays three resonances at 90.3 (CH), 29.1 and
23.3 (CH2) ppm. The latter is observed as a doublet with
a C-P coupling constant of 2.8 Hz, while the other two
resonances appear as singlets. The resonance corre-
sponding to the CR atom of the vinylidene ligand is
observed at 292.4 ppm, as a double doublet with both
C-P coupling constants of 14.7 Hz, whereas the reso-
nance due to the Câ atom appears at 92.4 ppm, also as
a double doublet but with both C-P coupling constants
of 4.1 Hz. In agreement with the structure shown in
Scheme 1, the 31P{1H} NMR spectrum shows an AB spin
system centered at 9.4 ppm and defined by ∆ν ) 948
Hz and J A-B ) 249 Hz.
The 1H, 13C{1H}, and 31P{1H} NMR spectra of 7
indicate that the structure of 7 is like that of 4 and that
the π-alkyne also acts as a four-electron-donor ligand.
1
1
In agreement with the H NMR spectrum of 4, the H
NMR spectrum of 7 in dichloromethane-d2 at 233 K
shows the resonance corresponding to the tCH proton
of the alkyne at 10.26 ppm, as a doublet with a H-P
coupling constant of 27.6 ppm. The resonance due to
the dCH proton of the vinylidene appears at 2.41 ppm,
as a double doublet of doublets with a H-H coupling
constant of 7.8 Hz and both H-P coupling constants of
4.5 Hz.27 In the high-field region, the spectrum contains
the hydride resonance, which is observed at -4.64 ppm,
as a double doublet with H-P coupling constants of 29.3
and 23.6 Hz. In the 13C{1H} NMR spectrum, the
resonances due to the C(sp) atoms of the alkyne appear
The related carbonyl complexes MH(η3-C3H5)(CO)-
(PiPr3)2 (M ) Os,25 Ru26) have been previously prepared,
by reaction of the corresponding hydride-chloro-carbonyl
compounds MHCl(CO)(PiPr3)2 with allylmagnesium bro-
mide. The previously mentioned spectroscopic data
agree well with those reported for these compounds.
Complex 6 was isolated as a brown oil in 90% yield.
Its formation involves the addition of the proton of the
(24) Buil, M. L.; Esteruelas, M. A.; Lo´pez, A. M.; On˜ate, E.
Organometallics 1997, 16, 3169.
(25) Schlu¨nken, C.; Werner, H. J . Organomet. Chem. 1993, 454, 243.
(26) Bohanna, C.; Esteruelas, M. A.; Herrero, J .; Lo´pez, A. M.; Oro,
L. A. J . Organomet. Chem. 1995, 498, 199.
(27) The resonance is temperature-invariant between 25 and -80
°C, suggesting that also in this case the vinylidene rotation is rapid
on the NMR time scale.

Elongated Dihydrogen-Osmium Complexes
Organometallics, Vol. 22, No. 12, 2003 2477
Sch em e 2
Ta ble 2. Selected Bon d Dista n ces (Å) a n d
An gles (d eg) for
at 161.5 (CCy) and 139.3 (tCH) ppm. The first of them
is observed as a broad signal, while the second one
appears as a double doublet with C-P coupling con-
stants of 11.7 and 4.9 Hz. The vinylidene ligand displays
a double doublet (J C-P ) J C-P′ ) 15.1 Hz) at 283.3 (CR)
and a broad signal at 111.7 (Câ) ppm. The 31P{1H} NMR
spectrum shows an AB spin system centered at 31.0
ppm, defined by ∆ν ) 342 Hz and J A-B ) 129 Hz.
The stability of 7 is much less than the stability of 4.
In solution, complex 7 decomposes to a mixture of
unidentified products. At room temperature, the decom-
position is complete after 20 min. The low stability of 7
is consistent with the parallel disposition of the carbon-
carbon triple bond of the alkyne with regard to the
P-Os-P direction, which imposes a high steric hin-
drance between the substituent of the alkyne and the
isopropyl groups of the phosphines.
[OsH{C6F 4C(O)CH3}{C(P h )CH2}(P iP r 3)2]BF 4 (9)
Os-P(1)
Os-P(2)
Os-O
Os-C(1)
Os-C(9)
2.445(6)
2.434(7)
2.153(6)
2.16(2)
Os-C(10)
O-C(7)
C(6)-C(7)
C(9)-C(10)
1.929(12)
1.231(15)
1.419(18)
1.336(19)
2.114(16)
P(1)-Os-P(2)
P(1)-Os-O
P(1)-Os-C(1)
P(1)-Os-C(9)
P(1)-Os-C(10)
P(1)-Os-H(01)
P(2)-Os-O
P(2)-Os-C(1)
P(2)-Os-C(9)
P(2)-Os-C(10)
P(2)-Os-H(01)
O-Os-C(1)
O-Os-C(9)
O-Os-C(10)
168.49(13) O-Os-H(01)
166(3)
89.9(2)
86.6(6)
86.1(5)
95.3(3)
83(4)
99.9(2)
90.0(6)
93.1(5)
91.1(3)
86(4)
C(1)-Os-C(9)
C(1)-Os-C(10)
C(1)-Os-H(01)
C(9)-Os-C(10)
C(10)-Os-H(01)
Os-C(1)-C(6)
Os-O-C(7)
158.0(3)
163.5(5)
93(4)
38.2(5)
104(3)
111.6(12)
120.0(8)
116.6(13)
116.2(14)
63.4(8)
78.4(8)
O-C(7)-C(6)
C(1)-C(6)-C(7)
Os-C(9)-C(10)
Os-C(10)-C(9)
74.8(5)
125.8(5)
88.8(4)
3. Rea ction s of [Os{C6X4C(O)CH3}(η2-H2)(H2O)-
(P iP r 3)2]BF 4 (X ) F , H) w ith P h en yla cetylen e. At
room temperature, the addition of 1.0 equiv of phenyl-
acetylene to an NMR tube containing a dichloromethane-
d2 solution of 2 leads to a complex mixture (Scheme 2).
After 10 min, the main components of the mixture are
the hydride-vinylidene-π-alkyne complex [OsH(dCd
CHPh)(η2-HCtCPh)(PiPr3)2]BF4 (8, about 27%) and the
hydride-metallacyclopropene compound 9 (about 45%).
At this temperature complex 8 evolves into the 1,4-
diphenylbutadiene derivative [OsH(η4-C4H4Ph2){[η2-
CH2dC(CH3)]PiPr2}(PiPr2nPr)]BF4 (10), while 9 decom-
poses to unidentified products. After 3 h, the main
component of the new mixture is 10 (about 25%),
according to the 31P{1H} NMR spectrum.
When the reaction is carried out in a Schlenk tube,
after 10 min, the hydride-metallacyclopropene complex
9 can be isolated from the mixture, by concentration of
the solution and subsequent addition of diethyl ether.
By this procedure, complex 9 was obtained as a green
solid in 35% yield. Interestingly, at room temperature,
the solutions of 9 in dichloromethane-d2 are stable for
several days. This suggests that the above-mentioned
decomposition of 9 is a consequence of its reaction with
any of the minor components of the mixture.
C(9)-C(10)-C(11) 133.4(13)
the alkyne gives rise to a doublet at 10.61 ppm, with a
H-P coupling constant of 25.8 Hz, whereas the reso-
nance due to the dCH proton of the vinylidene ligand
is observed at 3.77 ppm as a double doublet with both
H-P coupling constants of 4.5 Hz.27 The hydride
resonance appears at -3.14 ppm as a double doublet
with H-P coupling constants of 27.0 and 23.1 Hz. In
the 13C{1H} NMR spectrum, the resonances due to the
C(sp) atoms of the alkyne are observed at 152.6 (CPh)
and 139.4 (CH) ppm, as double doublets with C-P
coupling constants of 7.5 and 5.3 and 9.5 and 4.1 Hz,
respectively. The resonance corresponding to the CR
atom of the vinylidene appears at 290.5 ppm, as a
double doublet with both C-P constants of 15.1 Hz,
whereas the resonance due to the Câ atom is observed
at 110.6 ppm, also as a double doublet but with both
C-P constants of 5.6 Hz. The 31P{1H} NMR spectrum
shows an AB spin system centered at 29.6 ppm and
defined by ∆ν ) 170 Hz and J A-B ) 126 Hz.
Figure 3 shows a view of the structure of the cation
of 9. Selected bond distances and angles are listed in
Table 2. The coordination geometry around the osmium
atom can be rationalized as a distorted pentagonal
bipyramid with the two phosphorus atoms of the tri-
The spectroscopic data of 8 agree well with those of 4
and 7. In the 1H NMR spectrum, the tCH proton of

2478 Organometallics, Vol. 22, No. 12, 2003
Barrio et al.
Metallacyclopropene compounds have been limited
to early transition metals, mainly Mo,29 W,30 and Re.31
In general they have been prepared by external
nucleophilic attack on coordinated alkyne ligands.17a
Osmacyclopropene complexes are rare. In addition
to [OsH(κ2-O2CCH3){C(Ph)CH2}(PiPr3)2]BF4, we have
reported that the reactions of the dihydride [OsH2-
(κ2-O2CCH3)(H2O)(PiPr3)2]BF4 with alkynols lead to
hydride-hydroxyosmacyclopropene derivatives of the
type [OsH(κ2-O2CCH3){C[C(OH)RR′]CH2}(PiPr3)2]BF4,
which are unstable and in solution evolve into
the corresponding cyclic hydroxycarbene complexes
[Os(κ2-O2CCH3){C(Me)C(OH)RR′}(PiPr3)2]BF4.7p Har-
man and co-workers have shown that the electrophilic
extraction of the methoxy group of the coordinated olefin
in the complex [Os{η2-CH2dC(OMe)CH3}(NH3)5](OTf)2
F igu r e 3. Molecular diagram of the cation of complex
[OsH{C6F4C(O)CH3}{C(Ph)CH2}(PiPr3)2]BF4 (9).
affords the osmacyclopropene [Os{C(CH3)CH2}(NH3)5]-
(OTf)3.32
(29) (a) Davidson, J . L.; Murray, I. E. P.; Preston, P. N.; Russo, M.
V.; Manojlovic´-Muir, L.; Muir, K. W. J . Chem. Soc., Chem. Commun.
1981, 1059. (b) Green, M.; Norman, N. C.; Orpen, A. G. J . Am. Chem.
Soc. 1981, 103, 1267. (c) Allen, S. R.; Green, M.; Orpen, A. G.; Williams,
I. D. J . Chem. Soc., Chem. Commun. 1982, 826. (d) Allen, S. R.; Baker,
P. K.; Barnes, S. G.; Bottrill, M.; Green, M.; Orpen, A. G.; Williams, I.
D.; Welch, A. J . J . Chem. Soc., Dalton Trans. 1983, 927. (e) Davidson,
J . L.; Wilson, W. F.; Manojlovic´-Muir, L.; Muir, K. W. J . Organomet.
Chem. 1983, 254, C6. (f) Davidson, J . L.; Murray, I. E. P.; Preston, P.
N.; Russo, M. V. J . Chem. Soc., Dalton Trans. 1983, 1783. (g) Allen, S.
R.; Beevor, R. G.; Green, M.; Norman, N. C.; Orpen, A. G.; Williams,
I. D. J . Chem. Soc., Dalton Trans. 1985, 435. (h) Feher, F. J .; Green,
M.; Rodrigues, R. A. J . Chem. Soc., Chem. Commun. 1987, 1206. (i)
Allen, S. R.; Beevor, R. G.; Green, M.; Orpen, A. G., Paddick, K. E.;
Williams, I. D. J . Chem. Soc., Dalton Trans. 1987, 591. (j) Conole, G.
C.; Green, M.; McPartlin, M.; Reeve, C.; Woolhouse, C. M. J . Chem.
Soc., Chem. Commun. 1988, 1310. (k) Clegg, W.; Green, M.; Hall, C.
A.; Hockless, D. C. R.; Norman, N. C.; Woolhouse, C. M. J . Chem. Soc.,
Chem. Commun. 1990, 1330. (l) Gamble, A. S.; White, P. S.; Templeton,
J . L. Organometallics 1991, 10, 693. (m) Agh-Atabay, N. M.; Canoira,
L. J .; Carlton, L.; Davidson, J . L. J . Chem. Soc., Dalton Trans. 1991,
1175. (n) Carfagna, C.; Deeth, R. J .; Green, M.; Mahon, M. F.; McInnes,
J . M.; Pellegrini, S.; Woolhouse, C. B. J . Chem. Soc., Dalton Trans.
1995, 3975. (o) Kiplinger, J . L.; Richmond, T. G. Polyhedron 1997, 16,
409. (p) Guillemot, G.; Solari, E.; Scopelliti, R.; Floriani, C. Organo-
metallics 2001, 20, 2446.
(30) (a) Davidson, J . L.; Shiralian, M.; Manojlovic-Muir, L.; Muir,
K. W. J . Chem. Soc., Chem. Commun. 1979, 30. (b) Davidson, J . L.;
Vasapollo, G.; Manojlovic´-Muir, L.; Muir, K. W. J . Chem. Soc., Chem.
Commun. 1982, 1025. (c) Carlton, L.; Davidson, J . L.; Miller, J . C.;
Muir, K. W. J . Chem. Soc., Chem. Commun. 1984, 11. (d) Davidson, J .
L.; Shiralian, M.; Manojlovic´-Muir, L.; Muir, K. W. J . Chem. Soc.,
Dalton Trans. 1984, 2167. (e) Carlton, L.; Davidson, J . L.; Ewing, P.;
Manojlovic´-Muir, L.; Muir, K. W. J . Chem. Soc., Chem. Commun. 1985,
1474. (f) Carlton, L.; Davidson, J . L. J . Chem. Soc., Dalton Trans. 1987,
895. (g) Gamble, A. S.; Birdwhistell, K. R.; Templeton, J . L. J . Am.
Chem. Soc. 1990, 112, 1818. (h) Silva, C. J ., Giner, J . L.; Djerassi, C.
J . Am. Chem. Soc. 1992, 114, 295. (i) Feng, S. G.; Templeton, J . L.
Organometallics 1992, 11, 2168. (j) Kiplinger, J . L.; King, M. A.; Arif,
A. M.; Richmond, T. G. Organometallics 1993, 12, 3382. (k) Mayr, A.;
Asaro, M. F.; Glines, T. J .; Van Engen, D.; Tripp, G. M. J . Am. Chem.
Soc. 1993, 115, 8187. (l) Lee, T.-Y.; Mayr, A. J . Am. Chem. Soc. 1994,
116, 10300. (m) Kiplinger, J . L.; King, M. A.; Fechtenko¨tter, A.; Arif,
A. M.; Richmond, T. G. Organometallics 1996, 15, 5292. (n) Kiplinger,
J . L.; Richmond, T. G.; Arif, A. M.; Du¨cker-Benfer, C.; van Eldik, R.
Organometallics 1996, 15, 1545. (o) Giannini, L.; Guillemot, G.; Solari,
E.; Floriani, C.; Re, N.; Chiesi-Villa, A.; Rizzoli, C. J . Am. Chem. Soc.
1999, 121, 2797. (p) Legzdins, P.; Lumb, S. A.; Rettig, S. J . Organo-
metallics 1999, 18, 3128. (q) Frohnapfel, D. S.; White, P. S.; Templeton,
J . L. Organometallics 2000, 19, 1497. (r) Guillemot, G.; Solari, E.;
Floriani, C.; Re, N.; Rizzoli, C. Organometallics 2000, 19, 5218.
(31) (a) Pombeiro, A. J . L.; Hughes, D. L.; Richards, R. L.; Silvestre,
J .; Hoffmann, R. J . Chem. Soc., Chem. Commun. 1986, 1125. (b)
Carfagna, C.; Carr, N.; Deeth, R. J .; Dossett, S. J .; Green, M.; Mahon,
M. F.; Vaughan, C. J . Chem. Soc., Dalton Trans. 1996, 415. (c) Casey,
C. P.; Brady, J . T. Organometallics 1998, 17, 4620. (d) Casey, C. P.;
Brady, J . T.; Boller, T. M.; Weinhold, F.; Hayashi, R. K. J . Am. Chem.
Soc. 1998, 120, 12500. (e) Casey, C. P.; Chung, S. Inorg. Chim. Acta
2002, 334, 283.
isopropylphosphine ligands occupying trans positions
(P(1)-Os-P(2) ) 168.49(13)°). The osmium coordination
sphere is completed by the metalated ketone, which acts
with a bite angle O-Os-C(1) of 74.8(5)°, the hydride
ligand, and the atoms C(9) and C(10), which are
coordinated to the osmium atom to form a three-
membered ring (C(10)-Os-C(9) ) 38.2(5)°).
The M-C bond to the monosubstituted carbon (C(10))
is substantially shorter than the M-C bond to the
disubstituted carbon (C(9)). Thus, the Os-C(10) bond
length (1.929(12) Å) is statistically identical with the
Os-C double-bond distance found in the carbene com-
plex OsCl2(dCHCH2Ph)(CO)(PiPr3)2 (1.887(9) Å),8 while
the Os-C(9) bond length (2.114(16) Å) agrees well with
the values previously reported for Os-C(alkyl) distances
(mean value 2.16(5) Å).28 The C(9)-C(10) distance is
1.336(19) Å. Similar values have been reported for the
related complex [OsH(κ2-O2CCH3){C(Ph)CH2}(PiPr3)2]-
BF4, which has been prepared by reaction of phenyl-
acetylene with the dihydride complex [OsH2(κ2-O2CCH3)-
(H2O)(PiPr3)2]BF4.7m
In agreement with the Os-C(10) carbene and Os-
C(9) alkyl formulation, the resonances due to C(10) and
C(9) atoms appear in the 13C{1H} NMR spectrum at
272.9 and 4.2 ppm, respectively. In the 1H NMR
spectrum the most noticeable resonances are those
corresponding to the Os-CH2 and Os-H hydrogen
atoms, which are observed at 1.91 and -7.72 ppm. The
first of them appears as a triplet with a H-P constant
of 8.5 Hz, while the second one is observed as a double
triplet by spin coupling with the phosphorus nuclei of
the phosphines (J H-P ) 17.2 Hz) and the fluorine F(4)
of the metalated ketone (J H-F ) 10.6 Hz). The presence
of a hydride ligand in 9 is also supported by its IR
spectrum in KBr, which shows a ν(Os-H) band at 2210
cm-1. The 31P{1H} NMR spectrum contains a singlet at
3.7 ppm.
(28) Allen, F. H.; Kennard, O. 3D Search and Research Using the
Cambridge Structural Database. Chem. Des. Automation News 1993,
8 (1), 1, 31-37.

Elongated Dihydrogen-Osmium Complexes
Organometallics, Vol. 22, No. 12, 2003 2479
Sch em e 3
Although the dehydrogenation of coordinated cyclo-
alkylphosphines is a well-known process,34 the de-
hydrogenation of acyclic alkylphosphines to give R-
vinylphosphines is rare. We have previously reported
that complex OsH2Cl2(PiPr3)2 reacts with 2.0 equiv
of 1,5-cyclooctadiene and 2,5-norbornadiene to give
1.0 equiv of the corresponding monoolefin and the
isopropenylphosphine derivatives OsCl2(η4-diolefin)-
{η2-[CH2dC(CH3)]PiPr2} (diolefin ) COD, NBD).35
Transition-metal complexes containing R2PC(R′)dCH2
ligands are relatively scarce. These groups act as a
monodentate ligand,36 a bridge to two metal centers,37
and a chelating ligand.38 Complex 10 is a rare example
of the latter type of compounds in osmium chemistry.
It should be noted that the formation of 10 involves,
in addition to the previously metioned dimerization-
reduction tandem, the carbon skeletal isomerization of
one of the isopropyl groups of the other phosphine,
which is converted into a n-propylbis(isopropyl)phos-
phine ligand. This isomerization should involve the
initial C-H activation of a methyl group of the isomer-
ized isopropyl, followed by the â-alkyl elimination of the
other one. Thus, the process can be rationalized accord-
ing to Scheme 3.
F igu r e 4. Molecular diagram of the cation of complex
[OsH(η4-C4H4Ph2){[η2-CH2dC(CH3)]PiPr2}(PiPr2nPr)]BF4
(10).
Ta ble 3. Selected Bon d Dista n ces (Å) a n d
An gles (d eg) for [OsH(η4-C4H4P h 2)-
{[η2-CH2dC(CH3)]P iP r 2}(P iP r 2n P r )]BF 4 (10)a
Os-P(1)
Os-P(2)
Os-C(7)
Os-C(8)
Os-C(9)
Os-C(10)
Os-C(17)
Os-C(18)
C(7)-C(8)
2.425(2)
2.312(2)
2.385(7)
2.209(7)
2.165(7)
2.288(7)
2.271(10)
2.222(9)
1.382(10)
C(8)-C(9)
1.437(10)
1.390(11)
1.426(14)
1.855(8)
1.538(12)
1.554(14)
1.780(13)
1.498(12)
C(9)-C(10)
C(17)-C(18)
P(1)-C(29)
C(29)-C(39)
C(30)-C(31)
P(2)-C(17)
C(17)-C(19)
P(1)-Os-P(2)
P(1)-Os-M(1)
P(1)-Os-M(2)
P(1)-Os-M(3)
P(1)-Os-H(01)
P(2)-Os-M(1)
P(2)-Os-M(2)
P(2)-Os-M(3)
P(2)-Os-H(01)
M(1)-Os-M(2)
M(1)-Os-M(3)
141.52(8) M(1)-Os-H(01)
149.0(2)
155.4(3)
94.7(2)
102.3(3)
118.1(7)
118.4(7)
118.6(7)
117.2(6)
105.5(2)
106.7(2)
96.8(3)
63.2
107.5(2)
105.1(2)
56.8(3)
93.2
M(2)-Os-M(3)
M(2)-Os-H(01)
M(3)-Os-H(01)
C(7)-C(8)-C(9)
C(8)-C(9)-C(10)
C(9)-C(10)-C(11)
P(1)-C(29)-C(30)
The C-C cleavage via â-alkyl elimination has been
observed rarely. It has become recognized as an impor-
C(29)-C(30)-C(31) 107.8(8)
58.1(3)
108.4(4)
P(2)-C(17)-C(18)
P(2)-C(17)-C(19)
108.7(7)
126.6(9)
(33) (a) Crabtree, R. H. Chem. Rev. 1985, 85, 245. (b) Burk, M. J .;
Crabtree, R. H. J . Am. Chem. Soc. 1987, 109, 8025. (c) Aoki, T.;
Crabtree, R. H. Organometallics 1993, 12, 294. (d) Chaloner, P. A.;
Esteruelas, M. A.; J oo´, F.; Oro, L. A. Homogeneous Hydrogenation;
Kluwer Academic Publisher: Dordrecht, 1994; Chapter 2. (e) J ensen,
C. M. Chem. Commun. 1999, 2443. (f) Morales-Morales, D.; Lee, D.
W.; Wang, Z.; J ensen, C. M. Organometallics 2001, 20, 1144.
(34) See for example: (a) Hietkamp, S.; Stufkens, D. J .; Vrieze, K.
J . Organomet. Chem. 1978, 152, 347. (b) Arliguie, T.; Chaudret, B.;
J alon, F.; Lahoz, F. J . J . Chem. Soc., Chem. Commun. 1988, 998. (c)
Campion, B. K.; Heyn, R. H.; Tilley, T. D.; Rheingold, A. L. J . Am.
Chem. Soc. 1993, 115, 5527. (d) Christ, M. L.; Sabo-Etienne, S.;
Chaudret, B. Organometallics 1995, 14, 1082.
(35) Edwards, A. J .; Esteruelas, M. A.; Lahoz, F. J .; Lo´pez, A. M.;
On˜ate, E.; Oro, L. A.; Tolosa, J . I. Organometallics 1997, 16, 1316.
(36) See for example: (a) Holt, M. S.; Nelson, J . H.; Alcock, N. W.
Inorg. Chem. 1986, 25, 2288. (b) Rahn, J . A.; Holt, M. S.; O’Neil-
J onhson, M.; Nelson, J . H. Inorg. Chem. 1988, 27, 1316. (c) Rahn, J .
A.; Delian, A.; Nelson, J . H. Inorg. Chem. 1989, 28, 215. (d) Rahn, J .
A.; Holt, M. S.; Gray, G. A.; Alcock, N. W.; Nelson, J . H. Inorg. Chem.
1989, 28, 217. (e) Bhaduri, D.; Nelson, J . H.; Day, C. L.; J acobson, R.
A.; Solujic´, L.; Milosavljevic´, E. B. Organometallics 1992, 11, 4069. (f)
Adams, H.; Bailey, N. A.; Blenkiron, P.; Morris, M. J . J . Organomet.
Chem. 1993, 460, 73. (g) Knox, S. A. R.; Morton, D. A. V.; Orpen, A.
G.; Turner, M. L. Inorg. Chim. Acta 1994, 220, 201.
(37) See for example: (a) Wilson, W. L.; Nelson, J . H.; Alcock, N.
W. Organometallics 1990, 9, 1699. (b) Hogarth, G. J . Organomet. Chem.
1991, 407, 91. (c) Doyle, M. J .; Duckworth, T. J .; Manojlovic´-Muir, L.;
Mays, M. J .; Raithby, P. R.; Robertson, F. J . J . Chem. Soc., Dalton
Trans. 1992, 2703. (d) Acum, G. A.; Mays, M. J .; Raithby, P. R.; Solan,
G. A. J . Organomet. Chem. 1996, 508, 137.
(38) (a) Mercier, F.; Hugel-Le Goff, C.; Ricard, L.; Mathey, F. J .
Organomet. Chem. 1990, 389, 389. (b) Mathey, F. J . Organomet. Chem.
1990, 400, 149. (c) J i, H.; Nelson, J . H.; DeCian, A.; Fischer, J .; Solujic´,
L.; Milosavljevic´, E. B. Organometallics 1992, 11, 401.
C(18)-C(17)-C(19) 124.5(11)
a
M(1), M(2), and M(3) are the midpoints of the C(7)-C(8), C(9)-
C(10), and C(17)-C(18) bonds.
A few crystals of 10 suitable for an X-ray diffraction
study were obtained by slow diffusion of diethyl ether
into the dichloromethane-d2 solution containing the
mixture resulting from the addition of phenylacetylene
to 2. Figure 4 shows a view of the structure of the cation
of this compound. Selected bond distances and angles
are collected in Table 3.
The structure proves the formation of the diphenyl-
butadiene ligand, which is coordinated to the osmium
atom as a cis-diene with E-stereochemistry at both
carbon-carbon double bonds. This ligand is the result
of the reductive condensation of the vinylidene and
π-alkyne ligands of 8. The reductor is one of the
triisopropylphosphines, which undergoes dehydrogena-
tion of one of the isopropyl groups, to afford a mono-
isopropenylphosphine. As far as we know, this tandem
process involving the dimerization of an alkyne plus the
reduction of the resulting dimer, by hydrogen transfer
from an alkane,33 has no precedents.
(32) Chen, H.; Harman, W. D. J . Am. Chem. Soc. 1996, 118, 5672.

2480 Organometallics, Vol. 22, No. 12, 2003
Ta ble 4. Cr ysta l Da ta a n d Da ta Collection a n d Refin em en t for 4, 9, a n d 10
Barrio et al.
4
9
10
Crystal Data
formula
C
22H47BF4OsP2
C
34H53BF8OOsP2
C34H55BF4OsP2
molecular wt
color and habit
650.55
red
892.71
red
802.73
yellow
irregular block
monoclinic, P21/c
14.1849(12)
15.4206(12)
13.6054(11)
90
105.361(2)
90
2869.7(4)
4
irregular block
monoclinic, Cc
19.9856(14)
9.0906(7)
22.3226(16)
90
114.839(1)
90
3680.4(5)
4
irregular block
monoclinic, C2/c
29.790(6)
11.407(3)
22.239(6)
90
111.561(9)
90
7029(3)
8
symmetry, space group
a, Å
b, Å
c, Å
R, deg
â, deg
γ, deg
V, Å 3
Z
D
calc, g cm-3
1.506
1.611
1.517
Data Collection and Refinement
Bruker Smart APEX
diffractometer
λ(Mo KR), Å
0.71073
graphite oriented
ω scans
3.619
3, 57
monochromator
scan type
µ, mm-1
4.588
3, 57
296
3.763
3, 57
100
2θ, range deg
temp, K
173
no. of data collected
no. of unique data
no. of params/restraints
26 364
6924 (Rint ) 0.1078)
394/27
0.0488
0.0896
0.806
11 905
5980 (Rint ) 0.0736)
435/110
0.0495
0.1149
0.931
33 394
8241 (Rint ) 0.0717)
491/294
0.0587
0.1251
1.005
R1 [F2 > 2σ(F2)]
a
b
wR2 [all data]
Sc [all data]
R1(F) ) ∑||Fo| - |Fc||/∑|Fo|. wR2(F2) ) {∑[w(Fo2 - Fc2)2]/∑[w(Fo2)2]}1/2
.
c Goof ) S ) {∑[Fo2 - Fc2)2]/(n - p)}1/2, where n is the number
a
b
of reflections, and p is the number of refined parameters.
tant chain-termination step in early transition-metal-
based, model Ziegler-Natta, polymerization systems.39
In late transition-metal systems there are also some
reports in which â-alkyl elimination has been pro-
posed.35, 40
the midpoint of the C(8)-C(7) double bond (M(1)) of the
diene (H(01)-M-M(1) ) 149.0(2)°) and the midpoint of
the C(17)-C(18) double bond (M(3)) of the isopropenyl
group disposed trans to the midpoint (M(2)) of the other
carbon-carbon double bond (C(9)-C(10)) of the diene
(M(2)-Os-M(3) ) 155.4(3)°). The distortion of the ideal
octahedron appears to be a consequence of the bite
angles of the diene (M(1)-Os-M(2) ) 58.1(3)°) and the
isopropenylphosphine (P(2)-Os-M(3) ) 56.8(3)°).
The olefinic bond of the isopropenylphosphine ligand
coordinates to the osmium atom in an asymmetrical
fashion, with Os-C distances of 2.222(9) Å (Os-C(18))
and 2.271(10) Å (Os-C(17)). These bond lengths agree
well with those found in other osmium-olefin complexes
(between 2.13 and 2.28 Å).7i,35,41 Similarly, the olefinic
bond distance C(17)-C(18) (1.426(14) Å) is within the
range reported for transition-metal olefin complexes
(between 1.340 and 1.445 Å).42 The P(2)-C(17) distance
(1.780(13) Å) is about 0.05 Å shorter than the P(2)-
C(20) (1.834(8) Å) bond length. In accordance with the
sp2 hybridization for C(17), the angles P(2)-C(17)-
C(18), P(2)-C(17)-C(19), and C(18)-C(17)-C(19) are
108.7(7)°, 126.6(9)°, and 124.5(11)°, respectively.
The coordination geometry around the osmium atom
of 10 can be rationalized as being derived from a highly
distorted octahedron with the phosphorus atoms of the
phosphines occupying pseudo-trans positions (P(1)-Os-
P(2) ) 141.52(8)°), at opposite sides of an ideal coordi-
nation plane defined by the hydride disposed trans to
(39) See for example: (a) Watson, P. L.; Roe, D. C. J . Am. Chem.
Soc. 1982, 104, 6471. (b) Watson, P. L.; Parshall, G. W. Acc. Chem.
Res. 1985, 18, 51. (c) Bunel, E.; Burger, B. J .; Bercaw, J . E. J . Am.
Chem. Soc. 1988, 110, 976. (d) Bercaw, J . E. Pure Appl. Chem. 1990,
62, 1151. (e) Eshuis, J . J . W.; Tan, Y. Y.; Teuben, J . H.; Renkema, J .
J . Mol. Catal. 1990, 62, 277. (f) Kesti, M. R.; Waymouth, R. M. J . Am.
Chem. Soc. 1992, 114, 3565. (g) Eshuis, J . J . W.; Tan, Y. Y.; Meetsma,
A.; Teuben, J . H.; Renkema, J .; Evens, G. G. Organometallics 1992,
11, 362. (h) Resconi, L.; Piemontesi, F.; Franciscono, G.; Abis, L.;
Fiorani, T. J . Am. Chem. Soc. 1992, 114, 1025. (i) Yang, X.; J ia, L.;
Marks, T. J . J . Am. Chem. Soc. 1993, 115, 3392. (j) Hajela, S.; Bercaw,
J . E. Organometallics 1994, 13, 1147. (k) Sini, G.; Macgregor, S. A.;
Eisenstein, O.; Teuben, J . H. Organometallics 1994, 13, 9. (l) Guo, Z.;
Swenson, D. C.; J ordan, R. F. Organometallics 1994, 13, 1424. (m)
Brintzinger, H. H.; Fischer, D.; Mu¨lhaupt, R.; Rieger, B.; Waymouth,
R. M. Angew. Chem., Int. Ed. Engl. 1995, 34, 1143. (n) Bochmann, M.
J . Chem. Soc., Dalton Trans. 1996, 255. (o) Horton, A. D. Organome-
tallics 1996, 15, 2675. (p) Etienne, M.; Mathieu, R.; Donnadieu, B. J .
Am. Chem. Soc. 1997, 119, 3218. (q) Corradi, M. M.; J ime´nez Pindado,
G.; Sarsfield, M. J .; Thornton-Pett, M.; Bochmann, M. Organometallics
2000, 19, 1150.
(40) See for example: (a) Flood, T. C.; Statler, J . A. Organometallics
1984, 3, 1795. (b) Flood, T. C.; Bitler, S. P. J . Am. Chem. Soc. 1984,
106, 6076. (c) Thomsons, S. K.; Young, G. B. Organometallics 1989, 8,
2068. (d) Hartwig, J . F.; Bergman, R. G.; Andersen, R. A. Organome-
tallics 1991, 10, 3344. (e) Ermer, S. P.; Struck, G. E.; Bitler, S. P.;
Richards, R.; Bau, R.; Flood, T. C. Organometallics 1993, 12, 2634. (f)
Ankianiec, B. C.; Christou, V.; Hardy, D. T.; Thompson, S. K.; Young,
G. B. J . Am. Chem. Soc. 1994, 116, 9963. (g) McNeill, K.; Andersen,
R. A.; Bergman, R. G. J . Am. Chem. Soc. 1995, 117, 3625. (h)
Bharadwaj, S. S.; Schimdt, L. D. J . Catal. 1995, 155, 403.
The coordination of both double bonds of the diene is
also asymmetrical. The Os-C(terminal) distances (Os-
C(10) ) 2.288(7) Å and Os-C(7) ) 2.385(7) Å) are
significantly longer than the Os-C(central) bond lengths
(Os-C(9) ) 2.165(7) Å and Os-C(8) ) 2.209(7) Å). On
(41) (a) J ohnson, T. J .; Albinati, A.; Koetzle, T. F.; Ricci, J .;
Eisenstein, O.; Huffman, J . C.; Caulton, K. G. Inorg. Chem. 1994, 33,
4966. (b) Esteruelas, M. A.; Garc´ıa-Yebra, C.; Oliva´n, M.; On˜ate, E.
Organometallics 2000, 19, 3260. (c) Baya, M.; Esteruelas, M. A.; On˜ate,
E. Organometallics 2002, 21, 5681.
(42) Allen, F. H.; Davies, J . E.; Galloy, J . J .; J ohnson, O.; Kennard,
O.; Macrae, C. F.; Mitchell, E. M.; Mitchell, G. F.; Smith, J . M.; Watson,
D. G. J . Chem. Inf. Comput. Sci. 1991, 31, 187.

Elongated Dihydrogen-Osmium Complexes
Organometallics, Vol. 22, No. 12, 2003 2481
the other hand, both C(terminal)-C(central) distances
(C(7)-C(8) ) 1.382(10) Å and C(9)-C(10) ) 1.390(11)
Å) are shorter than the C(central)-C(central) bond
length (C(8)-C(9) ) 1.437(10) Å). These structural
parameters strongly support a η4-π-coordination of the
diene, which is characteristic of the vast majority of
middle and late transition-metal diene complexes.43 In
agreement with the η4-π-coordination, the dihedral
angle between the C(7)-Os-C(10) and C(7)-C(8)-
C(9)-C(10) planes (θ) is 80.0(4)° and the ∆d and ∆l
parameters44 have values of 0.15 and -0.05 Å, respec-
tively.
main components of the new mixture are 10 (about 35%)
and 12 (about 20%).
Complex 12 was prepared as a pure analyzed solid
by stirring of a dichloromethane solution of 3 under 1
atm of ethylene, at room temperature, for 15 min (eq
4). By this procedure, complex 12 was isolated in about
44% yield.
The coordination fashion of the butadiene in 10 differs
from that observed in the osmium(0) complex Os(η4-
C4H5Ph)(CO)(PiPr3)2, where on the basis of the θ, ∆d,
and ∆l parameters, a coordination intermediate between
the resonance forms η4-π and σ2-π has been proposed.45
1
In the H NMR spectrum of 10, the most noticeable
resonances are those corresponding to the dCH protons
of the butadiene ligand, which are observed at 5.68,
5.23, 3.90, and 2.07 ppm. In the high-field region, the
spectrum shows the hydride resonance, which appears
at -12.98 ppm, as a double doublet with H-P coupling
constants of 30.8 and 16.4 Hz. In the 13C{1H} NMR
spectrum, the resonances corresponding to the dCH-
carbon atoms of the butadiene are observed at 72.9,
71.0, 63.8, and 60.3 ppm, whereas the resonances due
to the C(sp2)-carbon atoms of isopropenyl group of the
isopropenylphosphine ligand appear at 58.1 and 45.9
ppm. The 31P{1H} NMR spectrum contains two doublets
at 1.4 and -11.0 ppm, with a P-P coupling constant of
117 Hz, in agreement with the mutually pseudo-trans
disposition of the phosphines.
The structure proposed for 12 is strongly supported
by its 1H, 13C{1H}, and 31P{1H} NMR spectra. In
agreement with a highly symmetrical distribution of
ligands around the osmium atom, the 1H NMR spectrum
shows aromatic resonances corresponding to only one
type of phenyl group between 8.54 and 7.21 ppm, only
one ketone-methyl resonance at 3.10 ppm, and only one
resonance for the methyl groups of the triisopropylphos-
phine ligands at 0.84 ppm. In the high-field region, the
spectrum contains the hydride resonance, which ap-
pears at -4.50 ppm as a triplet with a H-P coupling
constant of 9.9 Hz. The position of this ligand, between
the orthometalated phenyl groups, was inferred on the
basis of a NOE experiment. The saturation of the
hydride resonance increases the intensity of the phenyl
resonance corresponding to the hydrogen atoms dis-
posed ortho to the metal (42.6%), while the ketone-
methyl resonance does not show any NOE effect. The
13C{1H} NMR spectrum also shows resonances corre-
sponding to only one type of metalated ketone (for more
details see Experimental Section). The 31P{1H} NMR
spectrum contains a singlet at -7.3 ppm, in accordance
with the mutually trans disposition of the phosphine
ligands.
At room temperature, the addition of 1.0 equiv of
phenylacetylene to an NMR tube containing a dichlo-
romethane-d2 solution of 3 leads, after 10 min, to a
mixture of 8 (about 40%), the hydride-metallacyclopro-
pene 11 (about 20%), and other unidentified products
(Scheme 2).
The presence of 11 in the mixture is strongly sup-
1
ported by the H, 13C{1H}, and 31P{1H} NMR spectra.
1
The H NMR spectrum shows the resonance due to the
CH2-protons of the metallacyclopropene ligand at 1.62
ppm, as a triplet with a H-P coupling constant of 9.0
Hz. The hydride resonance is observed at -8.66 ppm,
also as a triplet but with a H-P coupling constant of
19.3 Hz. In the 13C{1H} NMR spectrum the carbon
atoms of the three-membered ring give rise to singlets
at 268.9 (CPh) and 6.1 (CH2) ppm. A singlet at 4.2 ppm
in the 31P{1H} NMR spectrum is also characteristic of
11.
The mixture is unstable, as that starting from 2,
and evolves. Complex 8 affords 10. However, there
are marked differences in behavior between 9 and 11.
In contrast to 9, complex 11 reacts with the free
ketone, present in the reaction medium, to give
4. Hyd r id e-Vin ylid en e-π-Alk yn e Com p lexes ver -
su s Hydr ide-Metallacyclopr open e Com pou n ds. The
formation of 4, 7-9, and 11 can be rationalized accord-
ing to Scheme 4. In a manner similar to the oxime
elongated dihydrogen complex [Os{C6H4C(O)CH3}(η2-
H2){N(OH)dC(CH3)2}(PiPr3)2]BF4,10 in solution, com-
plexes 2 and 3 release the ketone ligand as a conse-
quence of the migration of a hydrogen atom of the
elongated dihydrogen to the metalated-aryl carbon
atom. This release affords the equilibrium between 2
(or 3) and spectroscopically undetected concentrations
of a highly unsaturated monohydride. The monohydride
reacts with the alkynes to give the hydride-vinylidene-
π-alkyne derivatives (4, 7, and 8), while the reactions
of 2 and 3 with the alkynes lead to the hydride-
[OsH{C6H4C(O)CH3}2(PiPr3)2]BF4 (12). After 6 h, the
(43) Yasuda, H.; Nakamura, A. Angew. Chem., Int. Ed. Engl. 1987,
26, 723.
(44) ∆d ) {d[Os-C(10)] + d[Os-C(7)]}/2 - {d[Os-C(9)] + d[Os-
C(8)]}/2 and ∆l ) {d[C(10)-C(9)] + d[C(7)-C(8)]}/2 - d[C(8)-C(9)].
See ref 46.
(45) Bohanna, C.; Esteruelas, M. A.; Lahoz, F. J .; On˜ate, E.; Oro,
L. A.; Sola, E. Organometallics 1995, 14, 4825.

2482 Organometallics, Vol. 22, No. 12, 2003
Barrio et al.
Sch em e 4
this diolefin complex involves the dimerization of the
alkyne together with the reduction of the resulting
dimer, by hydrogen transfer from an isopropyl group of
one of the phosphines, which is dehydrogenated to afford
a mono-isopropenylphosphine ligand. One of the isopro-
pyl groups of the other phosphine undergoes a carbon
skeletal isomerization into n-propyl.
In contrast to [OsH(dCdCHR)(η2-HCtCR)(PiPr3)2]BF4
(R ) Cy, Ph), the hydride-osmacyclopropene compounds
are stable in solution. However, in the presence of
acetophenone, complex [OsH{C6H4C(O)CH3}{C(Ph)CH2}-
(PiPr3)2]BF4 affords [OsH{C6H4C(O)CH3}2(PiPr3)2]BF4.
In conclusion, the stabilization of elongated dihydro-
gen complexes containing metal-σ-carbon bonds allows
access to highly unsaturated monohydride intermedi-
ates, which can coordinate several alkyne molecules
and, under particular conditions, subsequently couple
them.
osmacyclopropene derivatives (9 and 11), in a way
similar to the dihydride [OsH2(κ2-O2CCH3)(H2O)(PiPr3)2]-
BF4.7m
Exp er im en ta l Section
Acetylene and cyclohexylacetylene favor the selective
formation of hydride-vinylidene-π-alkyne complexes.
However, phenylacetylene gives rise to a mixture of both
types of compounds. In agreement with this, it has been
shown that the presence of a phenyl substituent imposes
an increase of the stability of the metallacyclopropene
unit, by conjugation of the phenyl π orbitals with the π
orbital of the OsdC-carbon atom.7m
In addition, it should be noted that the concentration
of hydride-osmacyclopropene in the mixture starting
from 2 is higher than that starting from 3. This suggests
that the presence of fluorine substituents in the meta-
lated ketone stabilizes the five-membered osmium-
ketone ring.
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 OsH3{C6F4C(O)CH3}(PiPr3)2 (1),46 [Os{C6H4C(O)CH3}-
(η2-H2)(H2O)(PiPr3)2]BF4 (3), and [Os{C6H4C(O)CH3}(η2-H2)-
10
{N(OH)dC(CH3)2}(PiPr3)2]BF4 were prepared by the pub-
lished methods.
1H, 19F, 31P{1H}, and 13C{1H} NMR spectra were recorded
on either a Varian Unity 300, a Varian Gemini 2000, or a
Bruker AXR 300 MHz instrument. Chemical shifts (expressed
in parts per million) are referenced to residual solvent peaks
(1H, 13C{1H}), external H3PO4 (31P{1H}), or external CFCl3
(19F). Coupling constants, J and N (N ) J P-H + J P′-H for 1H
and N ) J P-C + J P′-C for 13C{1H}) are given in hertz. Infrared
spectra were run on a Perkin-Elmer 1730 spectrometer as
solids (KBr pellet or Nujol mull). C, H, and N analyses were
carried out in a Perkin-Elmer 2400 CHNS/O analyzer. Mass
spectral analyses were performed with a VG Austospec instru-
ment. In FAB+ mode, ions were produced with the standard
Cs+ gun at ca. 30 kV, and 3-nitrobenzyl alcohol (NBA) was
used in the matrix.
Con clu d in g Rem a r k s
This study has revealed that the reactions of the
elongated dihydrogen complexes [Os{C6X4C(O)CH3}(η2-
H2)(H2O)(PiPr3)2]BF4 (X ) F, H) with terminal alkynes,
RCtCH, give rise in a competitive manner to hydride-
vinylidene-π-alkyne compounds [OsH(dCdCHR)(η2-
HCtCR)(PiPr3)2]BF4 and hydride-osmacyclopropene spe-
P r ep a r a tion of [Os{C6F 4C(O)CH3}(η2-H2)(H2O)(P iP r 3)2]-
BF 4 (2). A red solution of 1 (100.0 mg, 0.142 mmol) in 12 mL
of dichloromethane was treated with HBF4‚H2O (21 µL, 0.170
mmol) and stirred for 30 min at room temperature. The
resulting solution was filtered through Celite and concentrated
under vacuum. The subsequent addition of diethyl ether (5
mL) caused the precipitation of an orange solid, which was
washed with further portions of diethyl ether and dried in
vacuo. Yield: 94.1 mg (82%). Anal. Calcd for C26H49BF8O2-
OsP2: C 38.62; H 6.11. Found: C 38.45; H 6.27. IR (KBr, cm-1):
ν(OH) 3362 (s), ν(OsH) 2195 (m), ν(CO) 1641 (s), ν(BF) 1050
(br). 1H NMR (300 MHz, CD2Cl2, 293K): δ 4.38 (br, 2H, H2O),
3.09 (dt, J H-F ) 4.8 Hz, J H-P ) 1.8 Hz, 3H, CH3), 1.88 (m, 6H,
PCH), 1.05 and 0.91 (both dvt, N ) 13.5 Hz, J H-H ) 6.6 Hz,
18H, PCHCH3), -6.63 (t, J P-H ) 8.4 Hz, 2H, OsH). 31P{1H}
NMR (121.42 MHz, CD2Cl2, 293 K): δ 14.5 (s). 19F NMR
(282.33 MHz, CD2Cl2, 293 K): δ -114.6, -136.6, -146.9 and
-168.4 (all m, Ph), -153.1 (br s, BF4). 13C{1H} NMR (75.42
cies [OsH{C6X4C(O)CH3}{C(R)CH2}(PiPr3)2]BF4. The
preferred formation of one of the two types of compounds
depends on the substituent R of the alkyne. When the
substituent is hydrogen or alkyl, hydride-vinylidene-π-
alkyne complexes are exclusively formed, while when
the substituent is phenyl, a mixture of both types of
derivatives is obtained.
With the exception of [OsH(dCdCH2)(η2-HCtCH)-
(PiPr3)2]BF4, which is a suitable starting material to
obtain other interesting organometallic compounds
such as OsH(η3-C3H5)(dCdCH2)(PiPr3)2 and [OsH-
{κ-N,κ-O[ONdC(CH3)2]}(tCCH3)(PiPr3)2]BF4, the hy-
dride-vinylidene-π-alkyne complexes are unstable in
solution.Complex[OsH(dCdCHCy)(η2-HCtCCy)(PiPr3)2]-
BF4 decomposes to unidentified products, while [OsH-
(dCdCHPh)(η2-HCtCPh)(PiPr3)2]BF4 evolves into the
diphenylbutadiene derivative [OsH(η4-C4H4Ph2){[η2-
CH2dC(CH3)]PiPr2}(PiPr2nPr)]BF4. The formation of
MHz, CD2Cl2, 293 K): δ 204.8 (s, CdO), 158.2 (dm, J C-F
35.0 Hz, Os-C), 152-124 (all m, Ph), 28.6 (d, J C-F ) 8.7 Hz,
)
(46) Barrio, P.; Castarlenas, R.; Esteruelas, M. A.; Lledo´s, A.;
Maseras, F.; On˜ate, E.; Toma`s, J . Organometallics 2001, 20, 442.

Elongated Dihydrogen-Osmium Complexes
Organometallics, Vol. 22, No. 12, 2003 2483
CH3), 24.6 (vt, N ) 25.3 Hz, PCH), 19.1 and 19.0 (both s,
PCHCH3). MS (FAB+): m/z 722 (M+ - H). T1(min) (ms, OsH2,
300 MHz, CD2Cl2, 213 K): 40 ( 1 (-6.63 ppm, 2H).
temperature and then was filtered through Celite and evapo-
rated to dryness. A brown oil was obtained, which was washed
with diethyl ether and dried in vacuo. Method c: an orange
solution of [(Os{C6H4CO)CH3}(η2-H2){N(OH)dC(CH3)2}-
(PiPr3)2]BF4 (182.1 mg, 0.230 mmol) in 12 mL of dichloro-
methane was treated with trimethylsilylacetylene (34 µL,
0.276 mmol) and stirred for 45 min at room temperature and
then was filtered through Celite and evaporated to dryness.
A brown oil was obtained, which was washed with diethyl
ether and dried in vacuo. Yield: 96.2 mg (90%), method a; 70.5
mg (80%), method b; 138.8 mg (86%), method c. IR (KBr, cm-1):
ν(OsH) 2120 (m), ν(CN) 1643 (s), ν(BF) 1050 (br). 1H NMR
(300 MHz, CD2Cl2, 293 K): δ 2.33 (m, 6H, PCH), 2.25 and 2.18
(both s, 3H, NCCH3), 1.41 (s, 3H, OstCCH3), 1.31 and 1.29
(both dvt, N ) 14.4 Hz, J H-H ) 7.2 Hz, 18H, PCHCH3), -6.81
(t, J P-H ) 17.1 Hz, 1H, OsH). 31P{1H} NMR (121.42 MHz, CD2-
Cl2, 293 K): δ 37.3 (s). 19F NMR (282.33 MHz, CD2Cl2, 293
K): δ -156.3 (br s). 13C{1H} NMR (75.42 MHz, CD2Cl2, 293
K): δ 283.8 (t, J C-P ) 9.4 Hz, OstC), 147.2 (s, NdC), 40.2 (s,
OstCCH3), 25.1 (vt, N ) 27.2 Hz, PCH), 22.1 (s, NCCH3), 19.6
(s, PCHCH3), 19.2 (s, NCCH3), 18.8 (s, PCHCH3). MS (FAB+):
m/z 612 (M+).
P r ep a r a tion of [OsH(dCdCHCy)(η2-HCtCCy)(P iP r 3)2]-
BF 4 (7). An orange solution of 2 (100.0 mg, 0.124 mmol)
(method a) or 3 (89.1 mg, 0.121 mmol) (method b) in 12 mL of
dichloromethane was treated with cyclohexylacetylene (35 µL,
0.273 mmol, method a; or 34 µL, 0.266 mmol, method b) and
stirred for 20 min at 233 K. The resulting solution was
concentrated in vacuo. The additon of diethyl ether led to a
brown oil, which was washed with diethyl ether and dried in
vacuo. Yield: 54.2 mg (55%), method a; 54.5 mg (54%), method
b. IR (Nujol, cm-1): ν(OsH) 2116 (m), ν(CtC) 1895 (m), ν(BF)
1050 (br). 1H NMR (300 MHz, CD2Cl2, 233 K, plus HMQC): δ
10.26 (d, J P-H ) 27.6 Hz, 1H, tCH), 3.68 and 3.40 (both m,
1H, Cy), 3.00 and 2.93 (both m, 3H, PCH), 2.41 (ddd, J H-H(CHCy)
) 7.8 Hz, J P-H ) J P′-C ) 4.5 Hz, 1H, dCH), 2.0-0.8 (m, 20H,
dCCy and tCCy), 1.5-1.0 (m, 36H, PCCH3), -4.64 (dd, J P-H
) 29.3 Hz, J P′-H ) 23.6 Hz, 1H, OsH). 31P{1H} NMR (121.42
MHz, CD2Cl2, 233 K): AB spin system: δ 31.0, ∆ν ) 342 Hz,
J A-B ) 129 Hz. 19F NMR (282.33 MHz, CD2Cl2, 233 K): δ
-155.2 (br s). 13C{1H} NMR (75.42 MHz, CD2Cl2, 233 K, plus
APT): δ 282.3 (dd, J P-C ) J P′-C ) 15.1 Hz, OsdC), 161.5 (br
s, tCCy), 139.3 (dd, J P-C ) 11.7 Hz, J P′-C ) 4.9 Hz, tCH),
111.7 (br s, dCH), 45.0 (s, CHCy), 34.8, 34.6, 26.0, 25.6, and
25.5 (all s, secundary carbon atoms of cyclohexyl groups), 31.3
(s, CHCy), 23.5 (d, J P-C ) 28.4 Hz, PCH), 20.1, 18.7, 18.6, and
17.2 (all s, PCHCH3). MS (FAB+): m/z 729 (M+).
[Os{C6F 4C(O)CH 3}(η2-H D)(D2O)(P iP r 3)2]BF 4 was ob-
tained from 2 in CD3OD‚D2O (2:0.1 mL) for 2 days. H NMR
(300 MHz, CD3OD, 293 K): δ -6.52 (tt(1:1:1), J H-P ) 8.4 Hz,
J H-D ) 3.3 Hz, 1H, OsH).
P r ep a r a tion of [OsH(dCdCH2)(η2-HCtCH)(P iP r 3)2]-
BF 4 (4). An orange solution of 2 (110.0 mg, 0.136 mmol)
(method a) or 3 (100.0 mg, 0.136 mmol) (method b) in 12 mL
of dichloromethane was stirred under an acetylene atmosphere
for 10 min at room temperature. The resulting solution was
filtered through Celite and concentrated in vacuo. The sub-
sequent addition of diethyl ether (5 mL) caused the precipita-
tion of a yellow solid, which was washed with further portions
of diethyl ether and dried in vacuo. Yield: 60.1 mg (68%),
1
method a; 63.1 mg (71%), method b. Anal. Calcd for C22H47
-
BF4OsP2: C 40.61; H 7.28. Found: C 40.77; H 7.38. IR (KBr,
cm-1): ν(OsH) 2161 (m), ν(CtC) 1882 (m), ν(BF) 1050 (br).
1H NMR (300 MHz, CD2Cl2, 293 K): δ 10.17 (part AA′ of a
AA′XX′ spin system, AA′ ) H2C2 and XX′ ) (PiPr3)2), 3.01 (m,
6H, PCH), 1.70 (t, J P-H ) 4.5 Hz, 2H, dCH2), 1.34 and 1.17
(both dvt, N ) 14.9 Hz, J H-H ) 7.3 Hz, 18H, PCHCH3), -3.58
(t, J P-H ) 22.9 Hz, 1H, OsH). 31P{1H} NMR (121.42 MHz, CD2-
Cl2, 293 K): δ 30.8 (s). 19F NMR (282.33 MHz, CD2Cl2, 293
K): δ -155.1 (br s). 13C{1H} NMR (75.42 MHz, CD2Cl2, 293
K): δ 283.6 (t, J P-C ) 14.8 Hz, OsdC), 137.3 (dd, J P-C ) 7.3
Hz, J P-C ) 3.2 Hz, H2C2), 90.3 (t, J P-C ) 6.0 Hz, dCH2), 25.0
(vt, N ) 29.9 Hz, PCH), 20.2 and 19.3 (both s, PCHCH3). MS
(FAB+): m/z 566 (M+ + H).
P r ep a r a tion of OsH(η3-C3H5)(dCdCH2)(P iP r 3)2 (5). A
yellow solution of 4 (101.0 mg, 0.155 mmol) in 9 mL of
tetrahydrofuran was treated with a solution of CH3MgCl in
tetrahydrofuran (62 µL, 0.186 mmol, 3 M) and stirred for 25
min at 213 K. Then the solvent was removed and pentane was
added to filter the ionic salts. The resulting solution was dried
in vacuo. A red oil was obtained. Yield: 82.1 mg (91%). IR
1
(KBr, cm-1): ν(OsH) 2020 (m). H NMR (300 MHz, C6D6, 293
K, plus COSY): δ 4.92 (m, 1H, CHallyl), 3.01 (m, 1H, CaHsyn),
2.89 (m, 1H, CaHanti), 2.63 and 2.37 (both m, 3H, PCH), 2.16
(m, 1H, CbHsyn), 1.46 (m, 1H, CbHanti), 1.31 (dd, J P-H ) 12.0
Hz, J H-H ) 7.2 Hz, 9H, PCCH3), 1.2 (this peak is hidden under
the PiPr3 signals, OsdCdCH2), 1.18 (m, 18H, PCCH3), 1.05
(dd, J P-H ) 12.0 Hz, J H-H ) 7.2 Hz, 9H, PCCH3), -9.33 (ddd,
J P-H ) 24.6 Hz, J P′-H ) 17.1 Hz, J H-Hanti <1 Hz, 1H, OsH).
1H{31P} NMR (300 MHz, C6D6, 293 K, allyl group): δ 4.94 (tt,
J H-Hanti ) 10.2 Hz, J H-Hsyn ) 6.9 Hz, 1H, CH), 3.01 (dd, J H-Hsyn
) 6.9 Hz, J Hsyn-Hsyn ) 3.0 Hz, 1H, CaHsyn), 2.89 (d, J H-H ) 10.2
Hz, 1H, CaHanti), 2.16 (dd, J H-Hsyn ) 6.9 Hz, J Hsyn-Hsyn ) 3.0
Hz, 1H, CbHsyn), 1.46 (dd, J H-H ) 10.2 Hz, J H(OsH)-Hanti <1 Hz,
1H, CbHanti). 31P{1H} NMR (121.42 MHz, C6D6, 293 K): AB
spin system: δ 9.4, ∆ν ) 948 Hz, J A-B ) 249 Hz. 13C{1H} NMR
(75.42 MHz, C6D6, 293 K, plus HETCOR): δ 292.4 (dd, J P-C
) J P′-C ) 14.7 Hz, OsdC), 92.4 (dd, J P-C ) J P′-C ) 4.1 Hz,
OsdC)CH2), 90.3 (s, CHallyl), 29.1 (s, CbH2allyl), 26.3 (dd, J P-C
) 23.1, J P′-C ) 1.8 Hz, PCH), 25.8 (dd, J P-C ) 21.1 Hz, J P′-C
) 1.3 Hz, PCH), 23.3 (d, J P-C ) 2.8 Hz, CaH2allyl), 20.8, 20.5,
20.2, and 19.9 (all s, PCHCH3).
Rea ction of [Os{C6F 4C(O)CH3}(η2-H2)(H2O)(P iP r 3)2]BF 4
w ith P h en yla cetylen e. To a solution of 2 (20.0 mg, 0.025
mmol) in 0.5 mL of CD2Cl2 at 298 K in an NMR tube was added
the stoichiometric amount of phenylacetylene (3 µL, 0.027
mmol). After 10 min the 1H NMR spectrum indicated the
formation of [OsH(dCdCHPh)(η2-HCtCPh)(PiPr3)2]BF4 (8) in
a 27% yield and [OsH{C6F4C(O)CH3}{C(Ph)CH2}(PiPr3)2]BF4
(9) in a 45% yield. After 3 h the 1H NMR spectrum showed
that the main component in the mixture was [OsH(η4-C4H4-
Ph2){[η2-CH2dC(CH3)]PiPr2}(PiPr2nPr)]BF4 (10) (about 25%).
The metallacyclopropene complex 9 was isolated by follow-
ing this procedure: an orange solution of 2 (100.0 mg, 0.124
mmol) in 12 mL of dichloromethane was treated with phenyl-
acetylene (14 µL, 0.124 mmol) and stirred for 10 min at room
temperature and then was filtered through Celite and con-
centrated to ca. 1 mL. Subsequent addition of diethyl ether
caused the precipitation of a green solid, which was washed
with further portions of diethyl ether and dried in vacuo.
Yield: 31.7 mg (35%).
P r ep a r a tion of [OsH {K-N,K-O[ONdC(CH3)2]}(tCCH3)-
(P iP r 3)2]BF 4 (6). This complex was prepared by three meth-
ods. Method a: a yellow solution of 4 (100.0 mg, 0.154 mmol)
in 12 mL of dichloromethane was treated with acetone oxime
(27.5 mg, 0.376 mmol) and stirred for 1 h at room temperature
and then was filtered through Celite and evaporated to
dryness. A brown oil was obtained, which was washed with
diethyl ether and dried in vacuo. Method b: an orange solution
of [Os{C6H4C(O)CH3}(η2-H2){N(OH)dC(CH3)2}(PiPr3)2]BF4
(100.2 mg, 0.126 mmol) in 12 mL of dichloromethane was
stirred under an acetylene atmosphere for 1 h at room
Da t a for [OsH (dCdCH P h )(η2-H C≡CP h )(P iP r 3)2]BF 4
(8). IR (Nujol, cm-1): ν(OsH) 2158 (m), ν(CtC) 1910 (m), ν(BF)
1060 (br). 1H NMR (300 MHz, CD2Cl2, 233 K): δ 10.61 (d, J P-H

2484 Organometallics, Vol. 22, No. 12, 2003
Barrio et al.
) 25.8 Hz, 1H, tCH), 7.50 (t, J H-H ) 7.5 Hz, 2H, m-Ph), 7.41
(t, J H-H ) 7.5 Hz, 1H, p-Ph), 7.18 (t, J H-H ) 7.5 Hz, 2H, m-Ph),
7.12 (d, J H-H ) 7.5 Hz, 2H, o-Ph), 6.95 (t, J H-H ) 7.5 Hz, 1H,
p-Ph), 6.53 (d, J H-H ) 7.5 Hz, 2H, o-Ph), 3.77 (dd, J P-H ) J P′-H
) 4.5 Hz, 1H, dCH), 3.00 and 2.46 (both m, 3H, PCH3), 1.34
(dd, J P-H ) 13.2 Hz, J H-H ) 6.6 Hz, 9H, PCCH3), 1.77 (m, 18H,
PCCH3), 1.05 (dd, J P-H ) 13.2 Hz, J H-H ) 6.6 Hz, 9H, PCCH3),
-3.14 (dd, J P-H ) 27.0 Hz, J P′-H ) 23.1 Hz, 1H, OsH). 31P{1H}
NMR (121.42 MHz, CD2Cl2, 233 K): AB spin system: δ 29.6,
∆ν ) 170 Hz, J A-B ) 126 Hz. 19F NMR (282.33 MHz, CD2Cl2,
233 K): δ -154.6 (br s). 13C{1H} NMR (75.42 MHz, CD2Cl2,
233 K): δ 290.5 (dd, J P-C ) J P′-C ) 15.1 Hz, OsdC), 152.6
for 15 min at room temperature. The resulting solution was
filtered through Celite and evaporated to dryness. The sub-
sequent addition of dichloromethane (0.5 mL) and diethyl ether
(5 mL) caused the precipitation of an orange solid, which was
washed with further portions of diethyl ether and dried in
vacuo. Yield: 55.2 mg (44%).
Da ta for [OsH{C6H4C(O)CH3}{C(P h )CH2}(P iP r 3)2]BF 4
(11). IR (KBr, cm-1): ν(OsH) 2113 (m), ν(CO) 1628 (s), ν(BF)
1060 (br). 1H NMR (300 MHz, CD2Cl2, 233 K): δ 10.20 (d, J H-H
) 7.5 Hz, 1H, Ph), 8.14 (t, J H-H ) 7.5 Hz, 1H, Ph), 8.07 (d,
J H-H ) 7.5 Hz, 1H, Ph), 7.70 (t, J H-H ) 7.5 Hz, 1H, Ph), 7.61
(t, J H-H ) 7.5 Hz, 1H, Ph), 7.6-6.9 (m, 4H, Os-Ph), 3.12 (s,
3H, CH3), 1.62 (t, J H-P ) 9.0 Hz, 2H, OsCH2), 1.52 (m, 6H,
PCH), 1.3-0.8 (m, 36H, PCHCH3), -8.66 (t, J H-P ) 19.3 Hz,
1H, OsH). 31P{1H} NMR (121.42 MHz, CD2Cl2, 233 K): δ 4.2
(s). 19F NMR (282.33 MHz, CD2Cl2, 233 K): δ -154.5 (br s).
13C{1H} NMR (75.42 MHz, CD2Cl2, 233 K): δ 268.9 (s, Osd
C), 215.2 (s, CdO), 189.6 (t, J C-P ) 11.3 Hz, Os-C), 146-125
(all s, aromatic carbon atoms), 26.3 (vt, N ) 24.4 Hz, PCH),
25.8 (s, CH3), 19.8 (s, PCHCH3), 6.1 (s, Os-CH2). MS (FAB+):
m/z 735 (M+).
(dd, J P-C ) 7.5 Hz, J P′-C ) 5.3 Hz, tCPh), 139.4 (dd, J P′-C
9.5 Hz, J P-C ) 4.1 Hz, tCH), 129.5, 129.2, 129.0, 126.4, 126.3,
and 125.6 (all s, aromatic carbon atoms), 110.6 (dd, J P-C
)
)
J P′-C ) 5.6, OsdCdC), 27.8 (d, J P-C ) 25.1 Hz, PCH), 21.2,
20.7, 19.3, and 19.1 (all s, PCHCH3). MS (FAB+): m/z 717 (M+).
Da ta for [OsH{C6F 4C(O)CH3}{C(P h )CH2}(P iP r 3)2]BF 4
(9). Anal. Calcd for C34H53BF8OOsP2: C 45.74; H 5.98.
Found: C 45.43; H 5.91. IR (KBr, cm-1): ν(OsH) 2210 (m),
1
ν(CO) 1629 (s), ν(BF) 1060 (br). H NMR (300 MHz, CD2Cl2,
293 K): δ 10.02 (br, 1H, Ph), 8.22 (t, J H-H ) 7.5 Hz, 1H, Ph),
7.71 (br, 1H, Ph), 7.39 (t, J H-H ) 7.5 Hz, 1H, Ph), 7.24 (d, J H-H
) 7.5 Hz, 1H, Ph), 3.26 (d, J H-F ) 5.4 Hz, 3H, CH3), 1.91 (t,
J H-P ) 8.5 Hz, 2H, OsCH2), 1.70 (m, 6H, PCH), 0.99 and 0.93
(both dvt, N ) 13.9 Hz, J H-H ) 6.9 Hz, 18H, PCHCH3), -7.72
Da ta for [OsH{C6H4C(O)CH3}2(P iP r 3)2]BF 4 (12). Anal.
Calcd for C34H57BF4O2OsP2: C 48.80; H 6.87. Found: C 48.49;
H 6.64. IR (KBr, cm-1): ν(OsH) 2020 (m), ν(CO) 1589 (s), ν(BF)
1060 (br). 1H NMR (300 MHz, CD2Cl2, 293 K): δ 8.54 (d, J H-H
) 7.8 Hz, 2H, Ph), 7.88 (dd, J H-H ) 7.8 Hz, J H-H ) 1.5 Hz,
2H, Ph), 7.31 (vtd, J H-H ) 7.8 Hz, J H-H ) 1.5 Hz, 2H, Ph),
7.21 (vt, J H-H ) 7.8 Hz, 2H, Ph), 3.10 (t, J P-H ) 1.5 Hz, 6H,
CH3), 1.47 (m, 6H, PCH), 0.84 (dvt, N ) 13.3 Hz, J H-H ) 6.6
Hz, 36H, PCHCH3), -4.50 (t, J P-H ) 9.9 Hz, 1H, OsH). 31P{1H}
NMR (121.42 MHz, CD2Cl2, 293 K): δ -7.3 (s). 19F NMR
(282.33 MHz, CD2Cl2, 293 K): δ -155.1 (br s). 13C{1H} NMR
(75.42 MHz, CD2Cl2, 293 K): δ 211.4 (s, CdO), 173.6 (t, J P-C
) 6.9 Hz, Os-C), 144.7 (s, Cipso), 147.7, 136.3, 134.0, and 123.7
(all s, Ph), 24.9 (s, CH3), 23.2 (vt, N ) 23.4 Hz, PCH), 18.9 (s,
PCHCH3). MS (FAB+): m/z 751 (M+).
Str u ctu r a l An a lysis of Com p lexes 4, 9, a n d 10. X-ray
data were collected for all complexes on a Bruker Smart APEX
CCD diffractometer equipped with a normal focus, 2.4 kW
sealed tube source (molybdenum radiation, λ ) 0.71073 Å)
operating at 50 kV and 40 mA. Data were collected over the
hemisphere or the complete sphere by a combination of three
or four sets. Each frame exposure time was 10-30 s covering
0.3° in ω. Data were corrected for absorption by using a
multiscan method applied with the SADABS47 program. The
structures for all compounds were solved by the Patterson
method. Refinement, by full-matrix least squares on F2 with
SHELXL97,48 was similar for all complexes, including isotropic
and subsequently anisotropic displacement parameters. In the
last cycles of anisotropic refinement, the shape and size of some
thermal ellipsoids suggest the presence of disorder in some
ligands in the three molecules. In 4, the BF4 anion was refined
in two sites with a common B atom (occupancies 0.57(1) and
0.43(1), respectively). Two methyls (C9A-C9B, C16A-C16B)
of the triisopropylphosphine ligands were refined in two
positions (0.5-0.5). These groups were refined with an iso-
tropic model and restrained geometry. In 9, two isopropyls
were observed also disordered. These groups were refined
isotropically with restrained geometries with occupancies of
0.75(8) (C23A, C24A, C25A); 0.25(8) (C23B, C24B, C25B);
0.58(5) (C29A, C30A, C31A); and 0.42(5) (C29B, C30B, C31B).
In 10, the anion was observed disordered over two positions
(0.52(2) and 0.48(2)) as result of a rotation over a B-F bond.
A phenyl group was observed split in two sites with occupan-
1
(td, J H-P ) 17.2 Hz, J H-F ) 10.6 Hz, 1H, OsH). H NMR (300
MHz, CD2Cl2, 233 K, aromatic region): δ 10.05 (d, J H-H ) 7.5
Hz, 1H, Ph), 8.19 (t, J H-H ) 7.5 Hz, 1H, Ph), 8.06 (d, J H-H
)
7.5 Hz, 1H, Ph), 7.73 (t, J H-H ) 7.5 Hz, 1H, Ph), 7.58 (t, J H-H
) 7.5 Hz, 1H, Ph); there are no significant changes in the other
signals. 31P{1H} NMR (121.42 MHz, CD2Cl2, 293 K): δ 3.7 (s).
19F NMR (282.33 MHz, CD2Cl2, 293 K): δ -96.1, -132.4,
-143.5, and -158.0 (all m, Ph) -155.1 (br s, BF4). 13C{1H}
NMR (75.42 MHz, CD2Cl2, 233 K): δ 272.9 (s, OsdC), 211.3
(s, CdO), 166.2 (dm, J C-F ) 46.8 Hz, Os-C), 152-125 (all m,
OsPhF), 144.6 (s, CipsoPh), 135.8, 134.3, 133.3, 131.7, and 131.5
(all s, Ph), 30.8 (d, J C-F ) 9.2 Hz, CH3), 26.3 (vt, N ) 25.5 Hz,
PCH), 19.1 (s, PCHCH3), 4.2 (s, Os-CH2). MS (FAB+): m/z
807 (M+).
Da t a for [OsH (η4-C4H 4P h 2){[η2-CH 2dC(CH 3)]P iP r 2}-
1
(P iP r 2n P r )]BF 4 (10). H NMR (300 MHz, CD2Cl2, 298 K): δ
7.6-7.0 (m, 10H, Ph), 5.68, 5.23, and 3.90 (all m, 1H, dCH
butadiene group), 3.2-0.5 (m, CH, CH2, and CH3 of the
phosphine groups), 2.07 (m, 1H, dCH butadiene group),
-12.98 (dd, J H-P ) 30.8 Hz, J H-P′ ) 16.4 Hz, 1H, OsH).
31P{1H} NMR (121.42 MHz, CD2Cl2, 298 K): δ 1.4 and -11.0
(both d, J P-P ) 117 Hz). 19F NMR (282.33 MHz, CD2Cl2, 298
K): δ -154.5 (br s). 13C{1H} NMR (75.42 MHz, CD2Cl2, 298
K): δ 131-125 (aromatic carbon atoms), 72.9, 71.0, 63.8, and
60.3 (CH carbon atoms of butadiene group), 58.1 (d, J C-P
)
11 Hz, PCd), 45.9 (d, J C-P ) 2 Hz, PCdCH2), 33-16 (aliphatic
carbon atoms of PiPr and PnPr groups). MS (FAB+): m/z 635
(M+ - Ph - 5H).
Rea ction of [Os{C6H4C(O)CH3}(η2-H2)(H2O)(P iP r 3)2]BF 4
w ith P h en yla cetylen e. To solutions of 3 (20.0 mg, 0.027
mmol) in 0.5 mL of CD2Cl2 at 298 K in an NMR tube was added
the stoichiometric amount of phenylacetylene (3 µL, 0.027
mmol). After 10 min the 1H NMR spectrum indicated the
formation of [OsH(dCdCHPh)(η2-HCtCPh)(PiPr3)2]BF4 (8) in
a 40% yield and [OsH{C6H4C(O)CH3}{C(Ph)CH2}(PiPr3)2]BF4
(11) in a 20% yield. After 6 h the 1H NMR spectrum showed
that the main components in the mixture were [OsH(η4-C4H4-
Ph2){[η2-CH2dC(CH3)]PiPr2}(PiPr2nPr)]BF4 (10) in a 35% yield
and [OsH{C6H4C(O)CH3}2(PiPr3)2]BF4 (12) in a 20% yield.
The complex 12 was isolated by following this procedure:
an orange solution of 3 (110.0 mg, 0.149 mmol) in 12 mL of
dichloromethane was stirred under an ethylene atmosphere
(47) Blessing, R. H. Acta Crystallogr. 1995, A51, 33-38. SADABS,
Area-detector absorption correction; Bruker-AXS: Madison, WI, 1996.
(48) SHELXTL Package v. 6.10; Bruker-AXS: Madison, WI, 2000.
Sheldrick, G. M. SHELXS-86 and SHELXL-97; University of Go¨ttin-
gen: Go¨ttingen, Germany, 1997.

Elongated Dihydrogen-Osmium Complexes
Organometallics, Vol. 22, No. 12, 2003 2485
cies of 0.67(2) (C1A to C6A) and 0.33 (2) (C1B to C6B) and an
isopropyl refined in two positions, 0.57(1) (C23A-C24A-C25A)
and 0.43(1) (C23B-C24B-C25B). In this case an anisotropic
refinement was performed with restrained geometry.
The hydrogen atoms for nondisordered groups were ob-
served or calculated and refined freely by using a restricted
riding model. Hydride ligands were located but they do not
refine appropriately, and fixed positions or fixed Os-H
distances were used. All the highest electronic residuals were
observed in close proximity of the Os centers and make no
chemical sense.
Ack n ow led gm en t . Financial support from the
MCYT of Spain (Project BQU2002-00606) is acknowl-
edged. P.B. thanks the “Ministerio de Educacio´n, Cul-
tura y Deporte” for her grant.
Su p p or tin g In for m a tion Ava ila ble: Tables of positional
and displacement parameters, crystallographic data, and bond
lengths and angles. This material is available free of charge
via the Internet at http://pubs.acs.org.
OM021043M