Reactions of an osmium-elongated dihydrogen complex with terminal alkynes: Formation of novel bifunctional compounds with amphoteric nature

Article abstract of DOI:10.1021/om0200656

The reactions of osmium-elongated dihydrogen complex with terminal alkynes were analyzed. The distribution of ligands around the osmium atom can be described as a distorted trigonal bipyramid with apical phosphines and inequivalent angles within the Y-shaped equatorial plane. The transformation of alkyne-carbene appears to occur via alkynyl species involving two dissociation-addition processes, where the oxime ligand plays a major role.

Full text of DOI:10.1021/om0200656

Organometallics 2002, 21, 2491-2503
2491
Rea ction s of a n Osm iu m -Elon ga ted Dih yd r ogen Com p lex
w ith Ter m in a l Alk yn es: F or m a tion of Novel Bifu n ction a l
Com p ou n d s w ith Am p h oter ic Na tu r 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 J anuary 29, 2002
The trihydride complex OsH3{C6H4C(O)CH3}(PiPr3)2 (1) reacts with HBF4‚H2O to give the
elongated dihydrogen derivative [Os{C6H4C(O)CH3}(η2-H2)(H2O)(PiPr3)2]BF4 (2), with a
separation between the hydrogen atoms of the elongated dihydrogen of 1.35 Å. The addition
of acetone oxime to dichloromethane solutions of 2 produces the substitution of the water
ligand by the oxime and the formation of Os{C6H4C(O)CH3}(η2-H2){N(OH)dC(CH3)2}(PiPr3)2]-
BF4 (3), which shows a hydrogen-hydrogen distance of 1.34 Å. Complex 3 reacts with
phenylacetylene, cyclohexylacetylene, and tert-butylacetylene to give acetophenone and the
oximate-carbyne derivatives [OsH{κ-N,κ-O[ONdC(CH3)2]}(tCCH2R)(PiPr3)2]BF4 (R ) Ph (4),
t
Cy (5), Bu (6)). The structure of 4 has been determined by X-ray diffraction analysis. The
distribution of ligands around the osmium atom can be described as a distorted trigonal
bipyramid with apical phosphines and inequivalent angles within the Y-shaped equatorial
plane. Complexes 4-6 have amphoteric nature, reacting with both KOH and HBF4‚Et2O.
The reactions with KOH afford the vinylidene derivatives OsH{κ-N,κ-O[ONdC(CH3)2]}-
(dCdCHR)(PiPr3)2 (R ) Ph (7), Cy (8), tBu (9)), whereas the reactions with HBF4‚Et2O give
the fluoro-oxime compounds [OsH{F---HONdC(CH3)2]}(tCCH2R)(PiPr3)2]BF4 (R ) Ph (10),
t
Cy (11), Bu (12)). The structures of 7 and 11 have been determined by X-ray diffraction
analysis. The distribution of ligands around the osmium atom of 7 is like that of 4, whereas
the geometry around the metallic center of 11 can be rationalized as a distorted octahedron
with the phosphine ligands in trans positions. Complexes 10, 11, and 12 contain a strong
intramolecular F- - -H hydrogen bond between the fluorine and the OH-hydrogen atom of
the oxime in the solid state and in dichloromethane solution (J H-F ) 67.5 (10), 68.1 (11),
and 68.7 (12) Hz). The formation of 4-12 is also discussed, on the basis of deuterium label
experiments.
In tr od u ction
rationalize, which hinders the design a priori of the
steps to obtain a particular ligand or molecule and even
to know the most useful dihydride for the process.
At first glance, one would think that the nature
of the obtained product from the reactions of
osmium-dihydrides with alkynes depends on the nature
of the substituent (R) of the alkyne. For instance,
the seven-coordinate osmium(IV) dihydride cation
[OsH2(κ2-O2CCH3)(H2O)(PiPr3)2]+ reacts with phenyl-
acetylene to give the metallocyclopropene deriva-
Hydrides are one of the best anchors to nail unsatur-
ated organic molecules in transition metal compounds.
Thus, ruthenium and osmium polyhydride complexes
have shown to be useful templates to carbon-carbon
and carbon-heteroatom coupling reactions.1 The pres-
ence of more than one hydrogen atom bonded to the
metallic center allows the access of several organic
molecules into the metal. This facilitates different types
of coupling reactions and the generation of organic
fragments with a rich organic chemistry.2
tive [OsH(κ2-O2CCH3){C(Ph)CH2}(PiPr3)2]+, while under
the same conditions tert-butylacetylene and (tri-
methylsilyl)acetylene afford hydride-carbyne compounds
The capacity of the osmium-dihydride complexes to
afford C-C coupling reactions has been little-studied.3
This is mainly due to the fact that the reactivity of this
type of species toward alkynes, HCtCR, is difficult to
(2) See for example: (a) Esteruelas, M. A.; Lahoz, F. J .; Lo´pez,
A. M.; On˜ate, E.; Oro, L. A. Organometallics 1994, 13, 1669. (b) Buil,
M. L.; Esteruelas, M. A.; Lo´pez, A. M.; On˜ate, E. Organometallics 1997,
16, 3169. (c) Bohanna, C.; Callejas, B.; Edwards, A. J .; Esteruelas,
M. A.; Lahoz, F. J .; Oro, L. A.; Ruiz, N.; Valero, C. Organometallics
1998, 17, 373. (d) Bohanna, C.; Buil, M. L.; Esteruelas, M. A.; On˜ate,
E.; Valero, C. Organometallics 1999, 18, 5176. (e) Castarlenas, R.;
Esteruelas, M. A.; On˜ate, E. Organometallics 2001, 20, 2294.
(3) Esteruelas, M. A.; Garc´ıa-Yebra, C.; Oliva´n, M.; On˜ate, E.;
Tajada, M. A. Organometallics 2000, 19, 5098.
* Corresponding author. E-mail: maester@posta.unizar.es. Fax: 34
976761187.
(1) Esteruelas, M. A.; Lo´pez, A. M. Ruthenium- and Osmium-hydride
compounds containing triisopropylphosphine as precursors for carbon-
carbon and carbon-carbon-heteroatom coupling reactions. Recent
Advances in Hydride Chemistry; Elsevier: Amsterdam 2001; Chapter
7, pp 189-284.
10.1021/om0200656 CCC: $22.00 © 2002 American Chemical Society
Publication on Web 05/14/2002

2492 Organometallics, Vol. 21, No. 12, 2002
Barrio et al.
of formula [OsH(κ2-O2CCH3)(tC-CH2R)(PiPr3)2]+,4 and
mixtures of both types of compounds has been found in
reactions with alkynols.5 However, the nature of the
Os-H2 interaction also seems to have a significant
influence. Thus, the six-coordinate osmium(IV) di-
hydride OsH2Cl2(PiPr3)2 reacts with phenylacetylene,
cyclohexylacetylene, 1-(trimethylsilyl)-1,4-pentadiyne,
and (trimethylsilyl)acetylene to give the hydride-
carbyne derivatives OsHCl2(tCCH2R)(PiPr3)2,6,7 related
to the above-mentioned cationic carbyne species, while
the reaction of the elongated dihydrogen derivative
OsCl2(η2-H2)(CO)(PiPr3)2 with phenylacetylene affords
the carbene OsCl2(dCHCH2Ph)(CO)(PiPr3)2.8
Sch em e 1
It has been recently shown that the hexa-
hydride OsH6(PiPr3)2 activates ortho-CH bonds of
aromatic9 and cycloalkyl10 ketones and ortho-CF
bonds9 of aromatic ketones to give the trihydride
derivatives OsH3{C6H4C(O)R}(PiPr3)2 (X ) H, F) and
OsH3{C6H8C(O)CH3}(PiPr3)2. We have now observed
that complex OsH3{C6H4C(O)CH3}(PiPr3)2 is a use-
ful precursor to prepare the elongated dihydrogen
ligands of 1 and the coordination of the water molecule.
The subsequent addition of acetone oxime to dichlo-
romethane solutions of 2 produces the substitution
of the water ligand by the oxime and the formation
compound [Os{C6H4C(O)CH3}(η2-H2){N(OH)dC(CH3)2}-
(PiPr3)2]+. Our interest in the use of osmium com-
plexes containing two hydrogen atoms bonded to the
metallic center as templates to carbon-carbon coupling
reactions, and therefore our interest in learning to
rationalize the reactivity of this type of derivatives
toward alkynes, prompted us to study the reactions of
of [Os{C6H4C(O)CH3}(η2-H2){N(OH)dC(CH3)2}(PiPr3)2]-
BF4 (3).
Complex 2 was isolated as an orange solid in 89%
yield. The presence of the water ligand in this compound
is strongly supported by its IR and 1H NMR spectra.
The IR spectrum in KBr shows a strong ν(OH) band at
[Os{C6H4C(O)CH3}(η2-H2){N(OH)dC(CH3)2}(PiPr3)2]+
with these organic molecules.
This paper reports the preparation and characteriza-
1
3418 cm-1, whereas the H NMR spectrum in dichlo-
romethane-d2 contains a broad singlet at 3.72 ppm,
characteristic for a coordinated water molecule. In the
high-field region of the spectrum, the hydrogen atoms
bonded to the metal display a triplet at -7.87 ppm with
a H-P coupling constant of 10.5 Hz. A variable-
temperature 300 MHz T1 study of this peak shows a
slight broadening of the signal, as a result of the
decrease of T2 with decreasing temperature,11 and gives
a T1(min) of 48 ( 2 ms at 193 K. This T1(min) value
corresponds to a hydrogen-hydrogen distance of 1.07
(fast spinning) or 1.35 (slow spinning) Å.12
tion of the elongated dihydrogen complex [Os{C6H4C(O)-
CH3}(η2-H2){N(OH)dC(CH3)2}(PiPr3)2]+, its reactions
with terminal alkynes, and the reactions of the resulting
oximate-carbyne derivatives with KOH and HBF4.
Resu lts a n d Discu ssion
1. P r ep a r a tion of [Os{C6H4C(O)CH3}(η2-H2)-
{N(OH)dC(CH3)2}(P iP r 3)2]BF4. This complex has been
prepared according to the reaction sequence shown in
Scheme 1. Treatment at room temperature of the
The treatment of 2 with methanol-d4-water-d2 yields
the partially deuterated derivative [Os{C6H4C(O)CH3}-
(η2-HD)(D2O)(PiPr3)2]BF4, which has a H-D coupling
constant of 4.2 Hz. According to eq 1,13 this value allows
the calculation of a separation between the hydrogen
atoms of 1.35 Å. The hydrogen-hydrogen distance in 2
agrees well with those found in the osmium complexes
OsCl2(η2-H2)(Hpz)(PiPr3)2 (1.27 Å),14 OsCl2(η2-H2)(NHd
trihydride OsH3{C6H4C(O)CH3}(PiPr3)2 (1) in diethyl
ether-methanol (10:1) with 1.4 equiv of HBF4‚
H2O affords the cationic elongated dihydrogen inter-
mediate [Os{C6H4C(O)CH3}(η2-H2)(H2O)(PiPr3)2]BF4 (2),
as a result of the protonation of one of the hydride
CPh2)(PiPr3)2 (1.24 Å),15 and OsX{NHdC(Ph)C6H4}-
(PiPr3)2 (X ) Cl, Br, I; 1.31 Å)16 and lies at about the
(4) Buil, M. L.; Eisenstein, O.; Esteruelas, M. A.; Garc´ıa-Yebra, C.;
Gutie´rrez-Puebla, E.; Oliva´n, M.; On˜ate, E.; Ruiz, N.; Tajada, M. A.
Organometallics 1999, 18, 4949.
(5) Buil, M. L.; Esteruelas, M. A.; Garc´ıa-Yebra, C.; Gutie´rrez-
Puebla, E.; Oliva´n, M. Organometallics 2000, 19, 2184.
(6) Espuelas, J .; Esteruelas, M. A.; Lahoz, F. J .; Oro, L. A.; Ruiz, N.
J . Am. Chem. Soc. 1993, 115, 4683.
(11) Hamilton, D. G.; Crabtree, R. H. J . Am. Chem. Soc. 1988, 110,
4126.
(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.; Halpern, J . J . Am. Chem. Soc. 1991, 113, 4173. (c) J essop, P. G.;
Morris, R. H. Coord. Chem. Rev. 1992, 121, 155.
(13) Maltby, P. A.; Schalf, 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.
(7) Complexes OsHCl2(tCCH2R)(PiPr3)2 (R ) Ph, CH3) have been
also obtained from the reactions of OsH2Cl2(PiPr3)2 with styrene and
propene, respectively. See: Spivak, G. J .; Coalter, J . N.; Oliva´n, M.;
Eisenstein, O.; Caulton, K. G. Organometallics 1998, 17, 999.
(8) Esteruelas, M. A.; Lahoz, F. J .; On˜ate, E.; Oro, L. A.; Valero, C.;
Zeier, B. J . Am. Chem. Soc. 1995, 117, 7935.
(9) Barrio, P.; Castarlenas, R.; Esteruelas, M. A.; Lledo´s, A.;
Maseras, F.; On˜ate, E.; Toma`s, J . Organometallics 2001, 20, 442.
(10) Barrio, P.; Castarlenas, R.; Esteruelas, M. A.; On˜ate, E.
Organometallics 2001, 20, 2635.
(14) Esteruelas, M. A.; Lahoz, F. J .; Oro, L. A.; On˜ate, E.; Ruiz, N.
Inorg. Chem. 1994, 33, 787.
(15) Barea, G., Esteruelas, M. A.; Lledo´s, A.; Lo´pez, A. M.; Tolosa,
J . I. Inorg. Chem. 1998, 37, 5033.

Osmium-Elongated Dihydrogen Complex
Organometallics, Vol. 21, No. 12, 2002 2493
center of the reported range (1.0-1.5 Å) for the elon-
gated dihydrogen derivatives.17
d(H-H) ) -0.0167J (H-D) + 1.42
(1)
The structure shown for 2 in Scheme 1 is proposed
on the basis of a NOE experiment and the 31P{1H} NMR
spectrum. The irradiation of the elongated dihydrogen
resonance gave an increase of 9% in the resonance
corresponding to the aromatic hydrogen atom disposed
ortho with regard to the Os-aryl bond, in accordance
with the mutually cis disposition of the Os-H2 and Os-
aryl bonds. In agreement with the mutually trans
disposition of the phosphine ligands, the 31P{1H} NMR
spectrum of 2 shows a singlet at 14.8 ppm.
Complex 3 was isolated in 86% yield, also as an
orange solid. In the IR spectrum in KBr the most
noticeable feature is a ν(OH) band at 3368 cm-1
,
corresponding to the oxime ligand. In the 1H NMR
spectrum in dichloromethane-d2, this ligand displays
three singlets at 11.24 (OH) and 2.42 and 2.32 (CH3)
ppm, whereas the elongated dihydrogen gives rise to a
triplet at -8.85 ppm with a H-P coupling constant of
10.8 Hz. In this case, the variable-temperature 300 MHz
T1 study of the elongated dihydrogen resonance gives a
T1(min) of 43 ( 1 ms at 203 K, which corresponds to a
hydrogen-hydrogen distance of 1.05 (fast spinning) or
1.33 (slow spinning) Å.12 The treatment of 3 with
methanol-d4 affords the partially deuterated derivative
F igu r e 1. Molecular diagram of the cation of complex
[OsH{κ-N,κ-O[ONdC(CH3)2]}(tCCH2Ph)(PiPr3)2]BF4 (4).
trans disposed to the nitrogen atom (N-Os-H(01) )
131(2)°), and the carbyne ligand trans disposed to the
[Os{C6H4C(O)CH3}(η2-HD){N(OD)dC(CH3)2}(PiPr3)2]-
BF4, which has a H-D coupling constant of 4.6 Hz.
According to eq 1, this value yields a hydrogen-
hydrogen separation of 1.34 Å, which agrees well with
that found in 2. The 31P{1H} NMR spectrum contains a
singlet at 6.25 ppm.
2. Reaction s of [Os{C6H4C(O)CH3}(η2-H2){N(OH)d
C(CH3)2}(P iP r 3)2]BF 4 w ith Alk yn es. The addition at
room temperature of 1.2 equiv of phenylacetylene,
cyclohexylacetylene, and tert-butylacetylene to dichlo-
romethane solutions of the elongated dihydrogen com-
plex 3 produces the release of acetophenone and the
formation of the hydride-oximate-carbyne complexes
[OsH{κ-N,κ-O[ONdC(CH3)2]}(tCCH2R)(PiPr3)2]BF4 (R
oxygen atom (C(1)-Os-O ) 164.9(3)°). However, since
the bite angle of the oximate ligand is very small, it
appears to be more reasonable to describe the oximate
group as a monodentate three-electron donor ligand. In
this way, the structure of 4 can be rationalized as a
distorted trigonal bipyramid with apical phosphines and
inequivalent angles within the Y-shaped equatorial
plane (H(01)-Os-M ) 111(2)°, H(01)-Os-C(1) )
t
) Ph (4), Cy (5), Bu (6)), according to eq 2.
Complexes 4-6 were isolated as lilac (4) or white (5
and 6) solids in high yield (about 70%) and characterized
by MS, elemental analysis, IR, and 1H, 13C{1H}, and
31P{1H} NMR spectroscopy. Complex 4 was further
characterized by an X-ray crystallographic study. A
view of the molecular geometry of the cation of this
complex is shown in Figure 1. Selected bond distances
and angles are listed in Table 1.
(18) Similar values have been found in other oximate compounds.
See for example: (a) Dickman, M. H.; Doedens, R. J . Inorg. Chem. 1982,
21, 682. (b) Porter, L. C.; Doedens, R. J . Acta Crystallogr., Sect. C 1985,
41, 838. (c) J aitner, P.; Huber, W.; Gieren, A.; Betz, H. J . Organomet.
Chem. 1986, 311, 379. (d) Pizzotti, M.; Porta, F.; Cenini, S.; Demartin,
F.; Masciocchi, N. J . Organomet. Chem. 1987, 330, 265. (e) Stella, S.;
Floriani, C.; Chiesi-Villa, A.; Guastini, C. J . Chem. Soc., Dalton Trans.
1988, 545. (f) Sharp, P. R.; Hoard, D. W.; Barnes, C. L. J . Am. Chem.
Soc. 1990, 112, 2024. (g) Hoard, D. W.; Sharp, P. R. Inorg. Chem. 1993,
32, 612. (h) Ang, H. G.; Kwik, W. L.; Ong, K. K. J . Fluorine Chem.
1993, 60, 43. (i) Vogel, S.; Huttner, G.; Zsolnai, L.; Emmerich, C. Z.
Naturforsch., B 1993, 48, 353. (j) Werner, H.; Daniel, T.; Knaup, W.;
Nu¨rnberg, O. J . Organomet. Chem. 1993, 462, 309. (k) Skoop, S. J .;
Campbell, J . P.; Gladfelter, W. L. Organometallics 1994, 13, 4137. (l)
Kukushkin, V. Y.; Tudela, D.; Pombeiro, A. J . L. Coord. Chem. Rev.
1996, 156, 333. (m) Skoog, S. J .; Gladfelter, W. L. J . Am. Chem. Soc.
1997, 119, 11049. (n) Castarlenas, R.; Esteruelas, M. A.; Gutie´rrez-
Puebla, E.; J ean, Y.; Lledo´s, A.; Mart´ın, M.; Toma`s, J . Organometallics
1999, 18, 4296. (o) Kukushkin, V. Y.; Pombeiro, A. J . L. Coord. Chem.
Rev. 1999, 181, 147.
At first glance, if one considers that the oximate
ligand occupies two sites in the coordination sphere of
the metal, the geometry around the osmium atom of 4
could be described as a very distorted octahedron with
the two phosphorus atoms of the phosphine ligands
disposed in opposite positions (P(1)-Os-P(2))168.13(7)°),
and the perpendicular plane formed by the oximate
(acting with a bite angle of 37.89(19)°),18 the hydride
(16) Barea, G.; Esteruelas, M. A.; Lledo´s, A.; Lo´pez, A. M.; On˜ate,
E.; Tolosa, J . I. Organometallics 1998, 17, 4065.
(17) Kubas, G. J .; Metal Dihydrogen and σ-Bond Complexes; Kluwer
Academic/Plenum Publishers: New York, 2001.

2494 Organometallics, Vol. 21, No. 12, 2002
Barrio et al.
Ta ble 1. Selected Bon d Dista n ces (Å) a n d An gles
to the metalated-aryl carbon atom. This process should
afford an oximate intermediate, which should give 4-6
in a similar way to the reactions of the previously
mentioned dihydride-acetate [OsH2(κ2-O2CCH3)(H2O)-
(PiPr3)]+ with tert-butylacetylene and (trimethylsilyl)-
acetylene.4 Alternatively, the release of the ketone could
be a consequence of the migration of a hydrogen atom
of the elongated dihydrogen to the metalated-aryl
carbon atom. This hydrogen transfer should afford the
unsaturated hydride-oxime species [OsH(η2-HCtCR)-
{N(OH)dC(CH3)2}(PiPr3)2]+, which could give 4-6 (vide
infra).
(d eg) for th e Com p lex
[OsH{K-N,K-O[ONdC(CH3)2]}(tCCH2P h )(P iP r 3)2]BF 4
(4)
Os-P(1)
Os-P(2)
Os-O
2.419(2)
2.417(2)
2.148(5)
2.057(6)
1.708(8)
1.44(5)
O-N
1.368(7)
1.266(9)
1.489(10)
1.504(11)
N-C(9)
C(1)-C(2)
C(2)-C(3)
Os-N
Os-C(1)
Os-H(01)
P(1)-Os-P(2)
P(1)-Os-O
168.14(7)
88.36(14)
89.72(16)
91.0(2)
92(2)
86.08(14)
92.30(16)
97.1(2)
78(2)
37.89(19)
164.9(3)
93(2)
127.0(3)
131(2)
Os-N-C(9)
Os-O-N
160.7(6)
67.4(3)
P(1)-Os-N
O-N-C(9)
124.3(7)
119.7(8)
121.0(8)
178.3(6)
115.8(7)
P(1)-Os-C(1)
P(1)-Os-H(01)
P(2)-Os-O
N-C(9)-C(10)
N-C(9)-C(11)
Os-C(1)-C(2)
C(1)-C(2)-C(3)
In the presence of 4.0 equiv of methanol-d4,23 the
reaction of the complex [Os{C6H4C(O)CH3}(η2-H2)-
P(2)-Os-N
{N(OD)dC(CH3)2}(PiPr3)2]BF4 (3-d 1), containing
a
P(2)-Os-C(1)
P(2)-Os-H(01)
O-Os-N
deuterium at the oxygen atom of the oxime, with
phenylacetylene affords the hydride-carbyne [OsH-
{κ-N,κ-O[ONdC(CH3)2]}(tCCD2Ph)(PiPr3)2]BF4 (4-d 2).
Complex 4-d 2 contains two deuteriums at the Câ
atom of the carbyne; deuterium at the free ketone
positions was not observed. This clearly indicates that
the hydrogen transfer from the oxime to the ketone does
not take place.
O-Os-C(1)
O-Os-H(01)
N-Os-C(1)
N-Os-H(01)
C(1)-Os-H(01)
102(2)
102(2)°, and C(1)-Os-M ) 146.4(3)°).19 This structure
is broad, similar to those of the neutral hydride-vinyl-
idene complexes MHCl(dCdCHR)(PiPr3)2 (M ) Ru,
Os)20 and cationic azavinylidene-carbyne compounds
[OsCl{dNdC(CH3)2}(tCCH2R)(PiPr3)2]+.21 The Os-
C(1) bond length of 1.708(8) Å is fully consistent with
an Os-C(1) triple bond formulation.22
Schemes 2-5 show three possible routes for the
formation of 4-6, starting from the intermediate [OsH-
(η2-HCtCR){N(OH)dC(CH3)2}(PiPr3)2]+.
According to the route a (Scheme 2), the formation
of the hydride-carbyne complexes should involve the
initial insertion of the alkyne into the Os-H bond
of [OsH(η2-HCtCR){N(OH)dC(CH3)2}(PiPr3)2]+ to give
unsaturated alkenyl species, which should evolve into
hydride-vinylidene intermediates by R-elimination. With
some exceptions,24 this has been previously considered
the most favored pathway to obtain hydride-vinylidene
complexes from hydride starting materials and terminal
alkynes.20b,25 The migration of the OH proton from the
oxime to the Câ atom of the vinylidene should afford
4-6.
Route b (Scheme 3) is similar to route a. The main
difference between them is the formation of the hydride-
vinylidene intermediates, which, in this case, involves
the 1,2-hydrogen shift over the carbon-carbon triple
bond of the η2-coordinated alkyne.
The IR and 1H, 13C{1H}, and 31P{1H} NMR spectra
of 4-6 are consistent with the structure shown in
Figure 1. The IR spectra in KBr contain a ν(Os-H) band
between 2160 and 2119 cm-1, along with the absorption
due to the [BF4]- anion with Td symmetry centered at
about 1050 cm-1, in agreement with the salt character
of the complexes. The 1H NMR spectra show the hydride
resonance as a triplet at about -6.5 ppm with a H-P
coupling constant of about 17 Hz. The 13C{1H} NMR
spectra contain the characteristic OstC resonance of
the carbyne ligands, which appears as a triplet at about
285 ppm, with a C-P coupling constant of about 9 Hz.
The 31P{1H} NMR spectra show a singlet between 35
and 38 ppm.
From a mechanistic point of view, it should be
mentioned that complex 3 reacts with deuterated-
phenylacetylene, PhCtCD, to give acetophenone and
the partially deuterated carbyne derivative 4-d 1, con-
taining 0.5 deuterium atom at the hydride position
(δOs-D, -6.2) and 0.25 deuterium atom at the Câ atom
of the carbyne (δC-D2, 2.89). The other 0.25 deuterium
atom of the starting alkyne is missing in the reaction
medium, whereas deuterium is not observed at the
ketone positions. The absence of deuterium at aceto-
phenone suggests that this molecule is released from
the osmium center before the activation of the alkyne.
The release of the ketone could be a result of the
hydrogen transfer from the oxygen atom of the oxime
According to route c (Scheme 4), the initial step should
be the formation of dihydrogen-alkynyl species, which
could evolve by a dissociative two-step (elimination-
addition) mechanism into the same hydrido-vinylidenes
as those obtained via routes a and b. A related H+-
(23) The reaction was carried out in the presence of methanol-d4
because complex 3-d 1 undergoes D/H exchange with traces of water
contained in the reaction medium, at a rate faster than the rate of the
reaction of 3-d 1 with phenylacetylene.
(24) (a) Esteruelas, M. A.; Oro, L. A.; Valero, C. Organometallics
1995, 14, 3596. (b) Crochet, P.; Esteruelas, M. A.; Lo´pez, M. A.;
Mart´ınez, M.-P.; Oliva´n, M.; On˜ate, E.; Ruiz, N. Organometallics 1998,
17, 4500.
(25) (a) van Asselt, A.; Burger, B. J .; Gibson, V. C.; Bercaw, J . E. J .
Am. Chem. Soc. 1986, 108, 5347. (b) Dziallas, M.; Werner, H. J .
Organomet. Chem. 1987, 333, C29. (c) Beckhaus, R.; Thiele, K.-H.;
Stro¨hl, D. J . Organomet. Chem. 1989, 369, 43. (d) Bell, T. W.;
Haddleton, D. M.; McCamley, A.; Partridge, M. G.; Perutz, R. N.;
Willner, H. J . Am. Chem. Soc. 1990, 112, 9212. (e) Gibson, V. C.;
Parkin, G.; Bercaw, J . E. Organometallics 1991, 10, 220. (f) Beckhaus,
R. J . Chem. Soc., Dalton Trans. 1997, 1991. (g) Luinstra, G. A.; Teuben,
J . H. Organometallics 1992, 11, 1793. (h) Beckhaus, R. Angew. Chem.,
Int. Ed. Engl. 1997, 36, 687. (i) Alvarado, Y.; Boutry, O.; Gutie´rrez,
E.; Monge, A.; Nicasio, M. C.; Poveda, M. L.; Pe´rez, P. J .; Ru´ız, C.;
Bianchini, C.; Carmona, E. Chem. Eur. J . 1997, 3, 860.
(19) M ) midpoint of the N-O bond.
(20) (a) Oliva´n, M.; Eisenstein, O.; Caulton, K. G. Organometallics
1997, 16, 2227. (b) Oliva´n, M.; Clot, E.; Eisenstein, O.; Caulton, K. G.
Organometallics 1998, 17, 3091. (c) Esteruelas, M. A.; Oro, L. A. Adv.
Organomet. Chem. 2001, 47, 1.
(21) Castarlenas, R.; Esteruelas, M. A.; On˜ate, E. Organometallics
2001, 20, 3283.
(22) Schubert, U. Carbyne Complexes; Verlagsgesellschaft mbH:
Weinheim, Germany, 1998; pp 40-58.

Osmium-Elongated Dihydrogen Complex
Organometallics, Vol. 21, No. 12, 2002 2495
Sch em e 2
Sch em e 3
If the reactions shown in eq 2 occur through route a,
one should expect one deuterium atom in the hydride
position of the product resulting from the reaction of 3
with deuterated phenylacetylene. However, if the reac-
tions take place through route b, the deuterium should
be located at the Câ atom of the carbyne ligand. As it
has been previously mentioned, the distribution of
deuterium atoms in the resulting product from the
reaction of 3 with deuterated phenylacetylene is 0.5
deuterium atom at the hydride position and 0.25
deuterium atom at the Câ atom of the carbyne ligand.
So, on the basis of this result routes a and b must be
rejected.
The presence of 0.5 deuterium atom at the hydride
position of the product resulting from the reaction of 3
with deuterated phenylacetylene can be easily explained
assuming that the reactions shown in eq 2 take place
through route c or d. The formation of η2-HD species
during the activation of the deuterated alkyne and the
subsequent dissociation of one of these atoms allows 0.5
deuterium atom at the hydride position of the resulting
hydride complex, according to the statistics. Further-
more, the implication of two dissociation-addition steps
of H+(D+) for the formation of the carbyne ligand
explains well the presence of an amount of deuterium
at the Câ atom of the carbyne, which depends on the
reaction medium. In this context, in should be noted
that in the absence of H/D exchange with the reaction
medium, 0.5 deuterium at the Câ atom of the carbyne
ligand should be expected for the reaction of 3 with
deuterated phenylacetylene and one deuterium should
be expected for the reaction of 3-d 1 with phenyl-
acetylene, in the presence of 4.0 equiv of methanol-d4.
The presence of two deuteriums at the Câ atom of the
carbyne ligand of the product of this later reaction
agrees well not only with a H/D exchange process
between the organometallic species and the reaction
medium but also with the higher strength of the
alkyl-D bond in comparison with the alkyl-H bond.27
Routes c and d involve the same two dissociation-
addition processes, and the difference between them is
the order of these steps. For route c, the first dissocia-
dissociation has been shown to be the key to the alkyne-
vinylidene transformation by 1,3-hydrogen shift in half-
sandwich ruthenium and osmium systems.26 The last
step of the reaction shown in eq 2 should be the
hydrogen transfer from the oxime into the Câ atom of
the vinylidene, as in routes a and b.
An alternative to route c is route d (Scheme 5), which
involves oximate-dihydrogen-vinylidene species formed
by migration of the OH proton of the oxime to the Câ
atom of the alkynyl group of [Os(CtCR)(η2-H2){N(OH)d
C(CH3)2}(PiPr3)2]+. In this case, the formation of 4-6
should be a result of an elimination-addition process
involving the dihydrogen and vinylidene ligands. A
similar attack has been proposed to the formation of
OsHCl2(tCCH2R)(PiPr3)2 from OsH2Cl2(PiPr3)2 and ter-
minal alkynes.6
(26) (a) de los R´ıos, I.; J imenez-Tenorio, M.; Puerta, M. C.; Valerga,
P. J . Am. Chem. Soc. 1997, 119, 6529. (b) Bustelo, E.; J ime´nez-Tenorio,
M.; Puerta, M. C.; Valerga, P. Organometallics 1999, 18, 950. (c)
Bustelo, E.; J ime´nez-Tenorio, M.; Puerta, M. C.; Valerga, P. Organo-
metallics 1999, 18, 4563. (d) Puerta, M. C.; Valerga, P. Coord. Chem.
Rev. 1999, 193, 3-195, 977. (e) 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. (f) Bustelo, E.; J ime´nez-Tenorio,
M.; Puerta, M. C.; Valerga, P. Eur. J . Inorg. Chem. 2001, 2391. (g)
Baya, M.; Crochet, P.; Esteruelas, M. A.; Lo´pez, A. M.; Modrego, J .;
On˜ate, E. Organometallics 2001, 20, 4291.
(27) Connors, K. A. Chemical Kinetics. The Study of Reaction Rates
in Solution; VCH Publisher: New York, 1990.

2496 Organometallics, Vol. 21, No. 12, 2002
Barrio et al.
Sch em e 4
Sch em e 5
tion-addition process involves the dihydrogen ligand,
while the dissociation of the HO proton of the oxime is
the first step of route d. Complex 3-d 1 does not exchange
the deuterium atom at the oxime with the hydrogen
atoms of the elongated dihydrogen ligand at a rate
comparable with the rate of the reactions shown in eq
2. However, the H/D exchange between the oxime of 3
and methanol-d4 is very fast. These observation agree
well with the fact that complex 3-d 1 can be selectively
prepared by treatment of 3 with methanol-d4 during a
short period of time (less than 10 min). The selective
formation of 3-d 1, starting from 3 and methanol-d4,
suggests that, for these systems, the dissociation of the
proton from a coordinated oxime is meaningfully faster
than the dissociation of a proton from a dihydrogen
ligand. So, route d, involving the dissociation of the HO
proton of the oxime before the dissociation of the
dihydrogen, appears to be the most reasonable pathway
for the formation of 4-6 according to eq 2.
(9)). The reactions are reversible; thus the addition of
1.0 equiv of HBF4‚Et2O to dichloromethane solutions of
7-9 regenerates 4-6 (eq 3).
3. Rea ction s of [OsH{K-N,K-O[ONdC(CH3)2]}(t
CCH2R)(P iP r 3)2]BF 4 w ith KOH. In agreement with
the participation of hydride-oximate-vinylidene species
as intermediates in the formation of 4-6, the treatment
of methanol solutions of these complexes with 2.0 equiv
of KOH affords the derivatives OsH{κ-N,κ-O[ONd
The protonation of the Câ atom of the vinylidene
ligands of 7-9 is fast, reversible, and selective and
occurs without detectable participation of the metal.
Thus, the addition of 1.0 equiv of DBF4‚D2O to dichlo-
t
C(CH3)2]}(dCdCHR)(PiPr3)2 (R ) Ph (7), Cy (8), Bu

Osmium-Elongated Dihydrogen Complex
Organometallics, Vol. 21, No. 12, 2002 2497
F igu r e 2. Molecular diagram of complex OsH{κ-N,κ-
O[ONdC(CH3)2]}(dCdCHPh)(PiPr3)2 (7).
Ta ble 2. Selected Bon d Dista n ces (Å) a n d An gles
(d eg) for th e Com p lex
F igu r e 3. Left: Variable-temperature 1H NMR spectra
(300 MHz) in C7D8 in the high-field region of OsH{κ-N,κ-
O[ONdC(CH3)2]}(dCdCHtBu)(PiPr3)2 (9). Right: Simu-
lated spectra for the rotational process.
OsH{K-N,K-O[ONdC(CH3)2]}(dCdCHP h )(P iP r 3)2 (7)
Os-P(1)
Os-P(2)
Os-O
2.3692(13)
2.3656(13)
2.216(4)
2.062(4)
1.787(5)
1.57(7)
O-N
1.351(5)
1.285(7)
1.350(8)
1.465(9)
N-C(1)
C(4)-C(5)
C(5)-C(6)
Os-N
ligands. However, two stabilizing interactions occur
when the CR2 group lies in the H-M-(three-electron
ligand) plane.20
The vinylidene ligand is bound to the metal in a
nearly linear fashion with an Os-C(4)-C(5) angle of
178.0(5)°. The Os-C(4) (1.787(5) Å) and C(4)-C(5)
(1.350(8) Å) bond lengths compare well with those found
in other osmium-vinylidene complexes28 and support the
vinylidene formulation.
Os-C(4)
Os-H(01)
P(1)-Os-P(2)
P(1)-Os-O
168.91(5)
88.84(10)
92.27(12)
91.25(16)
78(2)
91.39(10)
94.52(12)
90.87(16)
91(2)
36.58(15)
167.7(2)
102(2)
131.2(2)
138(2)
Os-O-N
65.5(2)
160.4(4)
121.4(5)
121.0(5)
118.4(5)
178.0(5)
123.4(6)
Os-N-C(1)
O-N-C(1)
P(1)-Os-N
P(1)-Os-C(4)
P(1)-Os-H(01)
P(2)-Os-O
N-C(1)-C(2)
N-C(1)-C(3)
Os-C(4)-C(5)
C(4)-C(5)-C(6)
P(2)-Os-N
P(2)-Os-C(4)
P(2)-Os-H(01)
O-Os-N
In the IR spectra of 7-9, the most noticeable absorp-
tion is that corresponding to the ν(Os-H) vibration,
which appears between 2110 and 2080 cm-1. At room
O-Os-C(4)
1
O-Os-H(01)
N-Os-C(4)
N-Os-H(01)
C(4)-Os-H(01)
temperature, the H NMR spectra show the resonance
corresponding to the dCHR proton of the vinylidene
ligands, which appears between 0.5 and 0.9 ppm. The
hydride resonance is observed between -8.0 and -8.7
ppm. At the same temperature, in the 13C{1H} NMR
spectra, the CR atom of the vinylidene ligands gives rise
between 287 and 284 ppm to a triplet with a C-P
coupling constant between 10.2 and 8.3 Hz, whereas the
Câ atom displays a singlet between 109 and 115 ppm.
The 31P{1H} NMR spectra show a singlet between 20
and 24 ppm.
90(2)
romethane solutions of 4 gives instantly the correspond-
ing carbyne derivative, containing 1.7 deuterium atoms
at the Câ atom of the carbyne, while deuterium at the
hydride position is not observed.
Figure 2 shows a view of the molecular geometry of
7. Selected bond distances and angles are listed in Table
2. Assuming that the oximate group acts as a mono-
dentated three-electron donor ligand, the structure of
7 can be rationalized as a distorted trigonal bipyramid
with apical phosphines (P(1)-Os-P(2) ) 168.91(5)°) and
inequivalent angles within the Y-shaped equatorial
plane (H(01)-Os-M ) 119(3)°, H(01)-Os-C(4) ) 90(3)°,
and C(4)-Os-M ) 150.2(2)°).19 This distribution of
ligands around of the metal agrees well with that found
in 4, and it is similar to that calculated for the chloro-
hydride-vinylidene RuHCl(dCdCH2)(PH3)2 (H-Ru-Cl
) 128.71°, H-Ru-CR ) 84.78°, CR-Ru-Cl ) 146.52°).20a
It has been argued that the preference for a Y structure
in this type of vinylidene complexes is originated by the
presence of the vinylidene ligand, which is a potent π
acceptor in the CR2 plane but a weak π donor in the
orthogonal plane. The donating property of πCC disfavors
a trans relationship of the three-electron donor and
vinylidene ligands since this maximizes the overlaps
between the occupied orbitals of the metal and the two
1
The H, 13C{1H}, and 31P{1H} NMR spectra of these
compounds are temperature-dependent. Figure 3 shows
1
the hydride region of the H NMR spectrum of 9 as a
function of the temperature. The spectra of 7 and 8 are
similar. At low temperature, the spectra contain two
hydride resonances. On raising the temperature, they
coalesce, until finally only one resonance is observed.
This behavior can be understood as the result of the
equilibrium between the two possible rotational isomers
of 7-9 (eq 4). The 13C{1H} and 31P{1H} NMR spectra
at low temperature also support the presence of both
dispositions of the vinylidenes in solution (see Experi-
mental Section).
For 7 and 9 the equilibrium constants were measured
in the range from -70 to 40 °C. The temperature
dependence of the equilibria provides the values
(28) Castarlenas, R.; Esteruelas, M. A.; Gutie´rrez-Puebla, E.; On˜ate,
E. Organometallics 2001, 20, 1545.

2498 Organometallics, Vol. 21, No. 12, 2002
Barrio et al.
∆H° ) 0.9 ( 0.2 kcal‚mol-1 and ∆S° ) 3.7 ( 0.9
cal‚mol-1‚K-1 for 7 and ∆H° ) 0.9 ( 0.2 kcal‚mol-1 and
∆S° ) 4.1 ( 1.2 cal‚mol-1‚K-1 for 9. The obtained values
indicate that, for both cases, the rotational isomers have
a similar thermodynamic stability, as at first glance
could be expected from the proposed structures.
Line shape analysis of the hydride resonances of 7
and 9 allows the calculation of the rate constants for
the rotation process. The activation parameters obtained
from the corresponding Eyring analysis are ∆Hq ) 11.3
( 0.6 kcal‚mol-1 and ∆Sq ) -4.7 ( 1.8 cal‚mol-1‚K-1
for 7 and ∆Hq ) 12.9 ( 0.5 kcal‚mol-1 and ∆Sq ) 4.3 (
1.2 cal‚mol-1‚K-1 for 9. The values of the activation
entropy, near zero, are consistent with a rotational
process, whereas the values of the activation enthalpy
agree well with the reported one for the chloro-deriva-
F igu r e 4. Molecular diagram of the cation of complex
[OsH{F---HOHdC(CH3)2}(tCCH2Cy)(PiPr3)2]BF4 (11).
sphere of the metal, the chemistry of these compounds
is relatively unexplored.31 To date, only a few osmium-
fluoride organometallic compounds have been reported,
between them the derivatives OsF(CO)2(NdNPh)-
(PPh3)2,32 [OsF2(CO)3]4,33 OsF(COF)(CO)2(PPh3)2,34 and
OsF2(CO)2(PR3)2 (PR3 ) PPh3, PCy3).35 In general,
fluoro-carbyne complexes are very rare;36 as far as we
know, the only fluoro-osmium-carbyne compound previ-
ously described is the derivative [OsHF(tCCH2Ph)-
(Hpz)(PiPr3)2]BF4.37
Complexes 10-12 were isolated as lilac (10) or white
(11 and 12) solids in high yield (between 60 and 90%)
and characterized by MS, elemental analysis, IR, and
1H, 13C{1H}, and 31P{1H} NMR spectroscopy. Complex
11 was further characterized by an X-ray crystal-
lographic study. A view of the molecular geometry of
the cation of 11 is shown in Figure 4. Selected bond
distances and angles are listed in Table 3.
tive OsHCl(dCdCHPh)(PiPr3)2 (11.2 ( 0.2 kcal‚mol-1 29
)
and the calculated rotational barrier for OsHCl(dCd
CHPh)(PH3)2 (8.2 kcal‚mol-1).30
4. R ea ct ion s of [OsH {K-N,K-O[ONdC(CH 3)2]}-
(tCCH 2R )(P iP r 3)2]BF 4 w it h H BF 4. The hydride-
oximate-carbyne complexes 4-6 are difunctional com-
pounds, which show amphoteric nature reacting not
only with Bro¨nsted bases but also with Bro¨nsted acids.
Thus, in addition to the reactions shown in eq 3,
these compounds undergo the attack of HBF4. Treat-
ment at room temperature of dichloromethane solu-
tions of 4-6 with 1.2 equiv of HBF4‚Et2O leads to
the instant formation of the fluoro-oxime derivatives
[OsH{F---HONdC(CH3)2}(tCCH2R)(PiPr3)2]BF4 (R )
t
Ph (10), Cy (11), Bu (12)), according to eq 5.
The geometry around the osmium atom can be
rationalized as a distorted octahedron with the two
phosphorus atoms of the triisopropylphosphine ligands
in trans positions (P(1)-Os-P(2) ) 161.91(4)°). The
perpendicular plane is formed by the hydride and
carbyne ligands, the oxime group trans disposed to the
hydride (H(01)-Os-N ) 162.3(16)°), and the fluoride
atom trans disposed to the carbyne (C(4)-Os-F(1) )
175.74(15)°). The carbyne formulation is supported by
the Os-C(4)-C(5) angle (176.4(4)°). The very short Os-
C(4) distance is fully consistent with an osmium-carbon
(31) Doherty, N. M.; Hoffman, N. W. Chem. Rev. 1991, 91, 553.
(32) Haymore, B. L.; Ibers, J . A. Inorg. Chem. 1975, 14, 2784.
(33) Brewer, S. A.; Holloway, J . H.; Hope, E. G. J . Chem. Soc., Dalton
Trans. 1994, 1067.
(34) Brewer, S. A.; Coleman, K. S.; Fawcett, J .; Holloway, J . H.;
Hope, E. G.; Russell, D. R.; Watson, P. G. J . Chem. Soc., Dalton Trans.
1995, 1073.
(35) Coleman, K. S.; Fawcett, J .; Holloway, J . H.; Hope, E. G.;
Russell, D. R. J . Chem. Soc., Dalton Trans. 1997, 3557.
(36) (a) Birdwhistell, K. R.; Tonker, T. L.; Templeton, J . L. J . Am.
Chem. Soc. 1985, 107, 4474. (b) Lemos, M. A. N. D. A.; Pombeiro, A. J .
L.; Hughes, D. L.; Richards, R. L. J . Organomet. Chem. 1992, 434, C6.
(c) Hills, A.; Hughes, D. L.; Kashef, N.; Lemos, M. A. N. D. A.;
Pombeiro, A. J . L.; Richards, R. L. J . Chem. Soc., Dalton Trans. 1992,
1775. (d) Almeida, S. S. P. R.; Pombeiro, A. J . L. Organometallics 1997,
16, 4469.
Although there is experimental evidence suggesting
that the fluoro complexes are stable when π-back-
bonding ligands are also present in the coordination
(29) Bourgault, M.; Castillo, A.; Esteruelas, M. A.; On˜ate, E.; Ruiz,
N. Organometallics 1997, 16, 636.
(30) Yang, S. Y.; Wen, T. B.; J ia, G.; Lin, Z. Organometallics 2000,
19, 5477.
(37) Esteruelas, M. A.; Oliva´n, M.; On˜ate, E.; Ruiz, N.; Tajada, M.
A. Organometallics 1999, 18, 2953.

Osmium-Elongated Dihydrogen Complex
Organometallics, Vol. 21, No. 12, 2002 2499
Ta ble 3. Selected Bon d Dista n ces (Å) a n d An gles
(d eg) for th e Com p lex
The F- - -H hydrogen bond in 10-12 is also supported
by the IR spectra of these compounds. In contrast to
the IR spectrum of 3, which shows a narrow ν(O-H)
band at 3368 cm-1, the IR spectra of 10-12 contain a
broad ν(O-H) absorption centered between 3220 and
3186 cm-1, thus shifted more than 140 cm-1 to lower
wavenumbers if compared with that of 3. In addition,
it should be mentioned that the IR spectra of 10-12
show, at about 1050 cm-1, the absorption of the [BF4]-
anion with Td symmetry. This is in agreement with the
salt character of these compounds and indicates that
any fluorine atom of the [BF4]- anion is not involved in
an intermolecular F- - -H hydrogen bond with the OH
hydrogen of the oxime.
[OsH{F ---HO(NdC(CH3)2}(tCCH2Cy)(P iP r 3)2]BF 4
(11)
Os-P(1)
Os-P(2)
Os-F(1)
Os-N
Os-C(4)
Os-H(01)
2.4272(12)
2.4198(12)
2.085(2)
2.252(4)
1.694(4)
1.22(4)
O-N
1.399(4)
1.279(4)
1.476(6)
1.528(6)
N-C(1)
C(4)-C(5)
C(5)-C(6)
P(1)-Os-P(2)
P(1)-Os-F(1)
P(1)-Os-N
P(1)-Os-C(4)
P(1)-Os-H(01)
P(2)-Os-F(1)
P(2)-Os-N
P(2)-Os-C(4)
P(2)-Os-H(01)
F(1)-Os-N
F(1)-Os-C(4)
F(1)-Os-H(01)
N-Os-C(4)
N-Os-H(01)
C(4)-Os-H(01)
161.91(4)
83.39(7)
94.52(10)
97.12(13)
77.2(16)
83.83(7)
95.38(9)
94.70(14)
89.0(16)
78.35(11)
175.74(15)
85.1(15)
105.80(16)
162.3(16)
90.9(15)
Os-N-O
111.7(3)
136.9(3)
111.4(4)
120.3(5)
120.9(4)
176.4(4)
115.7(4)
Os-N-C(1)
O-N-C(1)
N-C(1)-C(2)
N-C(1)-C(3)
Os-C(4)-C(5)
C(4)-C(5)-C(6)
The F- - -H hydrogen bond gives rise to a five-
membered Os-F---H-O-N ring, which is stable in dichlo-
romethane at room temperature. Thus, at this temper-
1
ature, H NMR spectra of 10-12 in dichloromethane-
d2 show at about 12 ppm a doublet with a H-F coupling
constant of about 68 Hz, corresponding to the OH proton
of the oxime ligand. This value is higher than that found
in the complex IrH(bq-NH2)F(PPh3)2 (52 Hz, at 193
K),40h where a F- - -H distance of 1.560 Å has been
calculated by DFT theoretical studies,40k and suggests
that the F- - -H hydrogen bond in 10-12 is stronger
than that in the iridium derivative.
triple bond,22 whereas the Os-C(4)-C(5) angle clearly
indicates the sp hybridization of C(4).
The Os-F(1) bond length (2.085(2) Å) is statistically
identical with the Os-F distance in the previously
mentioned complex [OsHF(tCCH2Ph)(Hpz)(PiPr3)2]BF4
(2.087(2) Å),37 where a F- - -H-N hydrogen bonding has
been proposed to exist, and about 0.05 Å longer than
the Os-F distances found in the dicarbonyl compounds
OsF2(CO)2(PCy3)2 (2.023(4) and 2.022(4) Å) and OsF2-
(CO)2(PPh3)2 (2.023(5) Å).35 Interestingly, the F(1)-
Os-N angle (78.35(11)°) largely deviates from the ideal
value of 90°, indicating an approach of the oxime group
to the fluorine atom, which is also shown by the
separation between the fluorine and oxygen atoms
(2.464(4) Å). Although the hydrogen atom of the oxime
group does not refine, at 173 K, it was located at 1.75 Å
from the fluorine atom in the difference Fourier maps.
This separation is shorter than the sum of the van der
Waals radii of hydrogen and fluorine [rvdW(H) ) 1.20,
The addition of acetone to the dichloromethane solu-
tions of 10-12 produces the release of HF and the
regeneration of the oximate complexes 4-6, suggesting
that the presence of the F- - -H hydrogen bond stabilizes
the Os-F bond in 10-12. In this context, it should be
noted that acetone can compete with the fluorine by the
OH proton of the oxime.
1
The H NMR spectra of 10 and 12 also support the
presence of the carbyne and hydride ligands. The CH2
hydrogen atoms of the carbynes display a broad singlet
between 1.50 and 2.90 ppm, whereas the hydride ligand
gives rise to a double triplet at about -7 ppm with H-F
and H-P coupling constants of about 7 and 17 Hz,
respectively. The 19F, 31P{1H}, and 13C{1H} NMR agree
1
well with the H NMR spectra and with the molecular
diagram shown in Figure 4. The 19F NMR spectra
contain a double triplet of doublets between -260 and
-266 ppm with a F-P coupling constant of about
38.5 Hz. In agreement with the 19F NMR spectra, the
31P{1H} NMR spectra show a doublet between 37 and
33 ppm. In the 13C{1H} NMR spectra, the most notice-
able resonance is that due to the CR atom of the carbyne
ligands, which appears as a double triplet between 277
and 285 ppm with C-F and C-P coupling constants of
about 110 and 8 Hz, respectively. The Câ atom of the
carbyne ligands gives rise to a doublet between 57 and
66 ppm with a C-F coupling constant of about 12 Hz.
The formation of 10-12 can be rationalized as an
addition-displacement two-step process. Initially, the
oxygen atom of the oximate group adds the proton of
HBF4 to afford an unsaturated oxime intermediate
where the metallic center is a Lewis acid stronger than
BF3. Thus, in the subsequent step, the metal of this
intermediate displaces to BF3 from F-. The addition of
the proton to the oximate ligand of 4-6, as the addition
of H+ to vinylidene ligands 7-9, is fast and selective
and occurs without detectable participation of the metal.
In agreement with this, we have observed that the
r
vdW(F) ) 1.47 Å]38 and suggests an intramolecular
F- - -H hydrogen bond, as a result of the interaction of
the electronegative fluorine with the acidic OH hydro-
gen of the oxime.
Of great importance in biological and organic chem-
istry,39 the hydrogen bonding is presently attracting
considerable interest in the chemistry of transition
metals.28,37,40
(38) Bondi, A. J . Phys. Chem. 1964, 68, 441.
(39) J effrey, G. A.; Saenger, W. Hydrogen Bonding in Biological
Structures; Springer: Berlin, 1991.
(40) (a) Stevens, R. C.; Bau, R.; Milstein, R.; Blum, O.; Koetzle, T.
F. J . Chem. Soc., Dalton Trans. 1990, 1429. (b) Lough, A. J .; Park, S.;
Ramachandran, R.; Morris, R. H. J . Am. Chem. Soc. 1994, 116, 8356.
(c) Peris, E.; Lee, J . C., J r.; Rambo, J . R.; Eisenstein, O.; Crabtree, R.
H. J . Am. Chem. Soc. 1995, 117, 3485. (d) Crabtree, R. H.; Eisenstein,
O.; Sini, G.; Peris, E. J . Organomet. Chem. 1998, 567, 7. (e) Crabtree,
R. H. J . Organomet. Chem. 1998, 557, 111. (f) Gusev, D. G.; Lough, A.
J .; Morris, R. H. J . Am. Chem. Soc. 1998, 120, 13138. (g) Buil, M. L.;
Esteruelas, M. A.; On˜ate, E.; Ruiz, N. Organometallics 1998, 17, 3346.
(h) Lee, D.-H.; Kwon, H. J .; Patel, B. P.; Liable-Sands, L. M.; Rheingold,
A. L.; Crabtree, R. H. Organometallics 1999, 18, 1615. (i) Esteruelas,
M. A.; Gutie´rrez-Puebla, E.; Lo´pez, A. M.; On˜ate, E.; Tolosa, J . I.
Organometallics 2000, 19, 275. (j) Castarlenas, R.; Esteruelas, M. A.;
On˜ate, E. Organometallics 2000, 19, 5454. (k) Clot, E.; Eisenstein, O.;
Crabtree, R. H. New J . Chem. 2001, 25, 66.

2500 Organometallics, Vol. 21, No. 12, 2002
Barrio et al.
usual procedures and distilled under argon prior to use. The
addition of 1.0 equiv of DBF4‚D2O to dichloromethane
starting material OsH3{C6H4C(O)CH3}(PiPr3)2 (1)9 and DBF4‚
D2O were prepared by the published methods.
Syn th esis of (CH3)2CdNOD. (CH3)2CdNOH was dissolved
in methanol-d4 and stirred for 20 h. Removal of the solvent
and addition of pentane afforded (CH3)2CdNOD as a white
solid.
NMR spectra were recorded on a Varian UNITY, a Varian
Geminy 2000, and a Bruker ARX 300 MHz instrument. 1H
(300 MHz) and 13C (75.42 MHz) NMR chemical shifts were
referenced to TMS by using known shifts of residual proton
or carbon signals in the solvents. 31P (121.42 MHz) NMR were
measured relative to external 85% phosphoric acid. MS data
solutions of 4 gives [OsH{F---DONdC(CH3)2]}(tCCH2-
Ph)(PiPr3)2]BF4 (10-d 1), containing 1.0 deuterium atom
at the oxygen of the oxime. Deuterium at the hydride
position was not observed.41
The presence of a deuterium at the oxygen atom of
the oxime of 10-d 1 is strongly supported by the 2H NMR
spectrum of this compound at room temperature, which
shows at 11.90 ppm a doublet with a D-F coupling
constant of 10 Hz. The value of this coupling constant
agrees well with the expected one according to the
gyromagnetic ratio of the involved nuclei42 and suggests
that the strength of the F- - -D deuterium bond is
similar to that of the F- - -H hydrogen bond.
were recorded on
a VG Austospec double-focusing mass
spectrometer operating in the positive mode; ions were pro-
duced with the Cs+ gun at ca. kV, and 3-nitrobenzyl alcohol
(NBA) was used in the matrix.
Con clu d in g Rem a r k s
Kin etic An a lysis. The equilibrium constants K ) k1/ k-1
of the two rotamers of 7 and 9 were calculated by 1H NMR
spectroscopy in toluene-d8. At temperatures below the coales-
cence point, the ratio was calculated by integration of the
hydride signals corresponding to the two rotamers and above
the coalescence temperature by measuring the chemical shift
of the exchange-averaged hydride resonance. A least-squares
fit of the values of ln K vs 1/T gave the thermodynamic
magnitudes ∆H° and ∆S° involved in this equilibrium. Error
analysis assumed a 10% error in the value of the equilibrium
constant and 1 K in the temperature. Errors were computed
by standard error propagation formulas for least-squares
fitting.43
This paper shows, once more, that the chemistry of
the osmium compounds containing two hydrogen atoms
bonded to the metallic center is fascinating and cannot
be easily rationalized. Not only each osmium-dihydride
complex but also each osmium-elongated dihydrogen
derivative has a particular behavior in the presence of
alkynes. In contrast to OsCl2(η2-H2)(CO)(PiPr3)2, which
affords carbene compounds, complex [Os{C6H4C(O)-
CH3}(η2-H2){N(OH)dC(CH3)2}(PiPr3)2]BF4 gives car-
byne derivatives.
1
In the presence of phenylacetylene, cyclohexylacetyl-
ene, and tert-butylacetylene the oxime-elongated dihy-
drogen complex eliminates acetophenone and the re-
sulting unsaturated monohydride intermediate gives
rise to [OsH{κ-N,κ-O[ONdC(CH3)2]}(tCCH2R)(PiPr3)2]-
Complete line-shape analyses of the H NMR spectra of the
complexes 7 and 9 were achieved using the program gNMR
(Cherwell Scientific Publishing Limited). The rate constants
for various temperatures were obtained by fitting calculated
to experimental spectra by full line shape iterations. The
transverse relaxation time, T2, was estimated at the lowest
interval of temperatures using the resonances corresponding
to the hydride ligands. The activation parameters ∆Hq and
∆Sq were calculated by least-squares fit of ln(k1/T) vs 1/T
(Eyring equation). Error analysis assumed a 10% error in the
rate constant and 1 K in the temperature. Errors were
computed by published methods.44
t
BF4 (R ) Ph, Cy, Bu). The transformation of alkyne-
carbyne appears to occur via alkynyl species involving
two dissociation-addition processes, where the oxime
ligand plays a main role.
Complexes [OsH{κ-N,κ-O[ONdC(CH3)2]}(tCCH2R)-
(PiPr3)2]BF4 are a novel type of bifunctional organo-
metallic derivatives, which have amphoteric nature
reacting with both KOH and HBF4. The reactions with
KOH afford the neutral vinylidene derivatives OsH{κ-
N,κ-O[ONdC(CH3)2]}(dCdCHR)(PiPr3)2, as a result of
the deprotonation of the CH2 group of the carbyne
ligands. The reactions with HBF4 give the fluoro-oxime
P r ep a r a tion of [Os{C6H4C(O)CH3}(η2-H2)(H2O)(P iP r 3)2]-
BF 4 (2). A red solution of 1 (100 mg, 0.136 mmol) in a mixture
of 10 mL of diethyl ether and 1 mL of methanol was treated
with HBF4‚H2O (23.3 µL, 0.190 mmol) and stirred for 30 min
at room temperature and then was evaporated to dryness.
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:
103.6 mg (89%). Anal. Calcd for C26H53BF4O2OsP2: C 42.39;
H 7.25. Found: C 42.63; H 7.65. IR (KBr, cm-1): ν(OH) 3418
(br), ν(OsH) 2184 (s), ν(CO) 1592 (s), ν(BF) 1050 (br). 1H NMR
(300 MHz, CD2Cl2, 293 K): δ 7.66 (br d, J H-H ) 6.6 Hz, 1H,
Ph), 7.53 (br d, J H-H ) 6.6 Hz, 1H, Ph), 6.93 and 6.87 (both
vtd, J H-H ) 6.6 Hz, J H-H ) 1.2 Hz, 1H, Ph), 3.72 (br, 2H, H2O),
3.01 (s, 3H, CH3), 1.99 (m, 6H, PCH), 1.17 and 0.97 (both dvt,
complexes [OsH{F---HONdC(CH3)2}(tCCH2R)(PiPr3)2]-
BF4, where a strong F- - -H hydrogen bond between the
fluorine and the OH proton of the oxime appears to
stabilize the Os-F bond.
In conclusion the elongated dihydrogen complex
[Os{C6H4C(O)CH3}(η2-H2){N(OH)dC(CH3)2}(PiPr3)2]-
BF4 reacts with terminal alkynes to give the bifunc-
tional organometallic compounds [OsH{κ-N,κ-O[ONdC-
(CH3)2]}(tCCH2R)(PiPr3)2]BF4, which are electrophiles
at the CH2 group of the carbyne ligands and nucleo-
philes at the oxygen atom of the oximate group.
N ) 13.2 Hz, J H-H ) 6.9 Hz, 18H, PCHCH3), -7.87 (t, J P-H
)
10.5 Hz, 2H, OsH). 31P{1H} NMR (121.42 MHz, CD2Cl2, 293
K): δ 14.8 (s). 19F NMR (282.33 MHz, CD2Cl2, 293 K): δ -155.2
(s). 13C{1H} NMR (75.42 MHz, CD2Cl2, 293 K): δ 209.7 (s, Cd
O), 177.8 (br, Os-C), 143.3 (s, CipsoPh), 145.7, 137.2, 134.7,
and 122.1 (all s, Ph), 26.7 (vt, N ) 24.6 Hz, PCH), 25.8 (s,
CH3), 21.2 and 20.8 (both s, PCHCH3). MS (FAB+): m/z 650
(M+ - H). T1(min) (ms, OsH2, 300 MHz, CD2Cl2, 193 K): 48 (
2 (-7.87 ppm, 2H).
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 the
(41) The partial deuteration of the CH2 group of the carbyne is
observed after several hours.
(42) Friebolin, H. Basic One-and Two-Dimensional NMR Spectros-
copy; VCH Verlagsgesellschaft: Weinheim, 1991.
(43) Bevington, P. R. Data Reduction and Error Analysis for the
Physical Sciences; McGraw-Hill: New York, 1969; Chapter 4.
(44) Morse, P. M.; Spencer, M. D.; Wilson, S. R.; Girolami, G. S.
Organometallics 1994, 13, 1646.

Osmium-Elongated Dihydrogen Complex
Organometallics, Vol. 21, No. 12, 2002 2501
NMR) in NMR tubes were treated with the stoichiometric
amount of phenylacetylene-d1, PhCtCD (3.5 µL, 0.031 mmol).
After 10 min the 1H NMR spectrum indicates the quantitative
formation of 4-d 1. 2H NMR (46.03 MHz, CH2Cl2, 293 K): δ
2.89 (br, 0.25D, CHDPh), -6.2 (br, 0.5D, OsD).
P r epar ation of [OsH{K-N,K-O[ONdC(CH3)2]}(tCCD2P h )-
(P iP r 3)2]BF 4 (4-d 2). To solutions of 2 (20 mg, 0.027 mmol) and
acetone oxime-d1 (2 mg, 0.027 mmol) in 0.5 mL of CD2Cl2 (1H
NMR) or CH2Cl2 (2H NMR) in NMR tubes were added 4 equiv
of methanol-d4 (5 µL) and 1 equiv of phenylacetylene (3 µL).
After 10 min the 1H NMR spectrum indicates the quantitative
formation of 4-d 2. 2H NMR (46.03 MHz, CH2Cl2, 293 K): δ
2.89 (br, 2D, CD2Ph).
P r epar ation of [OsH{K-N,K-O[ONdC(CH3)2]}(tCCH2Cy)-
(P iP r 3)2]BF 4 (5). This complex was prepared as described
for 4 starting from 100 mg (0.126 mmol) of 3 and cyclohexyl-
acetylene (19.5 µL, 0.151 mmol). A white solid was obtained.
Yield: 69.0 mg (68%). Anal. Calcd for C29H62BF4NOOsP2: C
44.67; H 8.01; N 1.80. Found: C 45.01; H 7.84; N 2.01. IR (KBr,
cm-1): ν(OsH) 2160 (m), ν(CN) 1631 (s), ν(BF) 1050 (br). 1H
NMR (300 MHz, CD2Cl2, 293 K): δ 3.5-0.9 (m, 11H, Cy), 2.33
(m, 6H, PCH), 2.26 and 2.13 (both s, 3H, NCCH3), 1.59 (br,
[Os{C6H 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 -7.78 (tt(1:1:1), J H-P ) 10.5 Hz,
J H-D ) 4.2 Hz, 1H, OsH).
1
P r ep a r a tion of [Os{C6H4C(O)CH3}(η2-H2){N(OH)dC-
(CH3)2}(P iP r 3)2]BF 4 (3). An orange solution of 2 (100 mg,
0.136 mmol) in 12 mL of dichloromethane was treated with
acetone oxime (10.9 mg, 0.149 mmol) and stirred for 45 min
at room temperature and then was filtered through Celite and
evaporated to dryness. 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: 80.0 mg (86%). Anal. Calcd for C29H58BF4NO2-
OsP2: C 43.99; H 7.38; N 1.77. Found: C 43.54; H 7.33; N
1.92. IR (KBr, cm-1): ν(OH) 3368 (s), ν(OsH) 2186 (s), ν(CO)
1
1592 (s), ν(CN) 1559 (s), ν(BF) 1050 (br). H NMR (300 MHz,
CD2Cl2, 293 K): δ 11.24 (s, 1H, OH), 7.91 (br d, J H-H ) 7.2
Hz, 1H, Ph), 7.89 (dd, J H-H ) 7.2 Hz, J H-H ) 1.8 Hz, 1H, Ph),
7.12 and 7.07 (both vtd, J H-H ) 7.2 Hz, J H-H ) 1.8 Hz, 1H,
Ph), 3.12 (t, J P-H ) 1.5 Hz, 3H, C(O)CH3), 2.42 and 2.32 (both
s, 3H, NCCH3), 1.79 (m, 6H, PCH), 1.14 and 0.94 (both dvt, N
) 13.2 Hz, J H-H ) 7.2 Hz, 18H, PCHCH3), -8.85 (t, J P-H
)
2H, OstCCH2), 1.33 and 1.31 (both dvt, N ) 13.5 Hz, J H-H
)
10.8 Hz, 2H, OsH). 31P{1H} NMR (121.42 MHz, CD2Cl2, 293
K): δ 6.25 (s). 19F NMR (282.33 MHz, CD2Cl2, 293 K): δ -155.4
(s). 13C{1H} NMR (75.42 MHz, CD2Cl2, 293 K): δ 210.1 (s, Cd
O), 181.9 (t, J P-C ) 5.9 Hz, Os-C), 166.9 (s, NdC), 142.2 (s,
6.9 Hz, 18H, PCHCH3), -6.75 (t, J P-H ) 17.4 Hz, 1H, OsH).
31P{1H} NMR (121.42 MHz, CD2Cl2, 293 K): δ 37.05 (s). 19F
NMR (282.33 MHz, CD2Cl2, 293 K): δ -155.3 (s). 13C{1H}
NMR (75.42 MHz, CD2Cl2, 293 K, plus dept): δ 287.5 (t, J C-P
) 8.7 Hz, OstC), 147.5 (s, NdC), 59.9 (s, OstCCH2), 35.1,
33.4, and 25.8 (all s, secondary carbon atoms of the cyclohexyl
group), 33.5 (s, primary carbon atom of the cyclohexyl group),
25.4 (vt, N ) 27.2 Hz, PCH), 22.3 (s, NCCH3), 19.6 and 19.2
(both s, PCHCH3), 18.8 (s, NCCH3). MS (FAB+): m/z 694 (M+).
P r ep a r a tion of [OsH{K-N,K-O[ONdC(CH3)2]}(tCCH2-
tBu )(P iP r 3)2]BF 4 (6). This complex was prepared as described
for 4 starting from 210 mg (0.265 mmol) of 3 and 3,3-dimethyl-
1-butyne (39 µL, 0.318 mmol). A white solid was obtained.
Yield: 153.0 mg (76%). Anal. Calcd for C27H60BF4NOOsP2: C
43.03; H 8.02; N 1.86. Found: C 43.37; H 7.77; N 2.23. IR (KBr,
cm-1): ν(OsH) 2140 (m), ν(CN) 1631 (s), ν(BF) 1050 (br). 1H
NMR (300 MHz, CD2Cl2, 293 K): δ 2.37 (m, 6H, PCH), 2.30
and 2.19 (both s, 3H, NCCH3), 1.57 (br, 2H, OstCCH2), 1.33
and 1.32 (both dvt, N ) 14.4 Hz, J H-H ) 7.5 Hz, 18H,
PCHCH3), 1.14 (s, 9H, C(CH3)3), -6.31 (t, J P-H ) 18.0 Hz, 1H,
OsH). 31P{1H} NMR (121.42 MHz, CD2Cl2, 293 K): δ 35.27
(s). 19F NMR (282.33 MHz, CD2Cl2, 293 K): δ -155.4 (s).
C
ipsoPh), 145.1, 136.2, 134.8 and 121.8 (all s, Ph), 28.1 (s, C(O)-
CH3), 25.7 (vt, N ) 24.9 Hz, PCH), 24.5 (s, NCCH3), 19.6 and
19.1 (both s, PCHCH3), 18.3 (s, NCCH3). MS (FAB+): m/z 704
(M+ - 2H). T1(min) (ms, OsH2, 300 MHz, CD2Cl2, 203 K): 43 (
1 (-8.87 ppm, 2H).
[Os{C6H 4C(O)CH 3}(η2-H D){N(OD)dC(CH 3)2}(P iP r 3)2]-
BF 4 was obtained from 3 stirred in CD3OD 1 day, the solvent
was removed, and then diethyl ether caused the precipitation
of an orange solid. 1H NMR (300 MHz, CD3OD, 293 K): δ
-9.09 (tt(1:1:1), J H-P ) 10.8 Hz, J H-D ) 4.6 Hz, 1H, OsH).
P r ep a r a tion of [Os{C6H4C(O)CH3}(η2-H2){N(OD)dC-
(CH3)2}(P iP r 3)2]BF 4 (3-d 1). To solutions of 2 (20 mg, 0.027
mmol) in 0.5 mL of CD2Cl2 (1H NMR) or CH2Cl2 (2H NMR) in
NMR tubes was added the stoichiometric amount of acetone
oxime-d1, DONdC(CH3)2 (2 mg, 0.027 mmol). After 10 min the
1H NMR spectrum indicates the quantitative formation of 3-d 1.
2H NMR (46.03 MHz, CH2Cl2, 293 K): δ 11.2 (br, 1D, OD).
P r epar ation of [OsH{K-N,K-O[ONdC(CH3)2]}(tCCH2P h )-
(P iP r 3)2]BF 4 (4). An orange solution of 3 (100 mg, 0.126 mmol)
in 12 mL of dichloromethane was treated with phenylacetylene
(17 µL, 0.151 mmol) and stirred for 20 min at room temper-
ature and then was filtered through Celite and evaporated to
dryness. Subsequent addition of dichloromethane (0.5 mL) and
diethyl ether (5 mL) caused the precipitation of a lilac solid,
which was washed with further portions of diethyl ether and
13C{1H} NMR (75.42 MHz, CD2Cl2, 293 K): δ 288.0 (t, J C-P
)
8.3 Hz, OstC), 147.4 (s, NdC), 66.0 (s, OstCCH2), 31.4 (s,
C(CH3)3), 30.2 (s, C(CH3)3), 25.2 (vt, N ) 26.7 Hz, PCH), 22.3
(s, NCCH3), 19.4 (s, PCHCH3), 19.1 (s, NCCH3). MS (FAB+):
m/z 668 (M+).
P r ep a r a tion of OsH{K-N,K-O[ONdC(CH3)2]}(dCdCH-
P h )(P iP r 3)2 (7). A lilac solution of 4 (135 mg, 0.174 mmol) in
12 mL of methanol was treated with a solution of KOH in
methanol (1.8 mL, 0.348 mmol, 0.1888 N) and stirred for 10
min at room temperature, then the solvent was removed and
toluene was added to filter the ionic salts. The resulting
solution was dried in vacuo, and methanol was added to afford
a yellow solid, which was washed with methanol at -78 °C
and dried in vacuo. Yield: 90.0 mg (75%). Anal. Calcd for
C29H55NOOsP2: C 50.78; H 8.08; N 2.04. Found: C 51.22; H
7.94; N 1.92. IR (KBr, cm-1): ν(OsH) 2107 (m), ν(CN) 1627
(s). 1H NMR (300 MHz, C6D6, 293 K): δ 7.46 (d, J H-H ) 7.2
Hz, 2H, HortoPh), 7.38 (t, J H-H ) 7.2 Hz, 2H, HmetaPh), 6.94 (t,
J H-H ) 7.2 Hz, 1H, HparaPh), 2.48 (m, 6H, PCH), 2.09 (s, 6H,
NC(CH3)2), 1.35 and 1.30 (both dvt, N ) 13.2 Hz, J H-H ) 6.9
Hz, 18H, PCHCH3), 0.53 (br, OsdCdCH), -8.18 (br, 1H, OsH).
31P{1H} NMR (121.42 MHz, C6D6, 293 K): δ 23.81 (s). 13C{1H}
dried in vacuo. Yield: 66.4 mg (65%). Anal. Calcd for C29H56
-
BF4NO2OsP2: C 45.02; H 7.30; N 1.81. Found: C 45.07; H 7.41;
N 1.92. IR (KBr, cm-1): ν(OsH) 2119 (m), ν(CN) 1578 (s),
1
ν(BF) 1050 (br). H NMR (300 MHz, CD2Cl2, 293 K): δ 7.4-
7.2 (m, 5H, Ph), 2.89 (s, 2H, OstCCH2), 2.26 (s, 3H, NCCH3),
2.22 (m, 6H, PCH), 2.18 (s, 3H, NCCH3), 1.25 (dvt, N )
14.4 Hz, J H-H ) 7.2 Hz, 36H, PCHCH3), -6.32 (t, J P-H ) 17.1
Hz, 1H, OsH). 31P{1H} NMR (121.42 MHz, CD2Cl2, 293 K): δ
37.16 (s). 19F NMR (282.33 MHz, CD2Cl2, 293 K): δ -155.3
(s). 13C{1H} NMR (75.42 MHz, CD2Cl2, 293 K, plus dept): δ
282.6 (t, J C-P ) 9.1 Hz, OstC), 147.6 (s, NdC), 128.6 (s, Cipso
-
Ph), 129.6, 129.3, and 128.7 (all s, Ph), 58.6 (s, OstCCH2),
25.4 (vt, N ) 27.2 Hz, PCH), 22.3 (s, NCCH3), 19.5 and
19.1 (both s, PCHCH3), 19.0 (s, NCCH3). MS (FAB+): m/z 668
(M+).
NMR (75.42 MHz, C6D6, 293 K, plus dept): δ 286.9 (t, J C-P
10.2 Hz, OsdC), 140.4 (s, NdC), 134.5 (s, CipsoPh), 128.4 (s,
paraPh), 123.1 and 121.7 (both s, Ph), 109.4 (s, OsdCdCHPh),
24.8 (vt, N ) 24.0 Hz, PCH), 22.6 (s, NCCH3), 20.4 and 19.8
)
P r epar ation of [OsH{K-N,K-O[ONdC(CH3)2]}(tCCH2P h )-
(P iP r 3)2]BF 4 P a r tia lly Deu ter a ted (4-d 1). Solutions of 3 (25
mg, 0.031 mmol) in 0.5 mL of CD2Cl2 (1H NMR) or CH2Cl2 (2H
C

2502 Organometallics, Vol. 21, No. 12, 2002
Barrio et al.
(both s, PCHCH3), 18.4 (s, NCCH3). 1H NMR (300 MHz, C7D8,
233 K): δ 7.5-6.8 (m, 10H, Ph), 2.56 and 2.50 (both s, 3H,
NCCH3), 2.30 (m, 6H, PCH), 1.96 (s, 6H, NC(CH3)2), 1.81 (s,
6H, PCH), 1.2-1.1 (m, 72H, PCHCH3), 0.32 and 0.30 (both br
s, OsdCdCH), -7.97 and -8.70 (both t, J P-H ) 16.6 Hz, 1H,
OsH). 31P{1H} NMR (121.42 MHz, C7D8, 233 K): δ 23.8 and
23.0 (both s). 13C{1H} NMR (75.42 MHz, C7D8, 233 K): δ_286.3
(t, J C-P ) 9.8 Hz, OsdC), 285.7 (t, J C-P ) 8.3 Hz, OsdC), 140.1
and 140.0 (both s, NdC), 134.6 and 133.7 (both s, CipsoPh),
122.8, 122.1, 121.4, and 121.3 (all s, Ph), 108.8 and 108.2 (both
s, OsdCdCHPh), 25.1 (vt, N ) 23.5 Hz, PCH), 23.8 (vt, N )
22.6 Hz, PCH), 22.7 (s, NCCH3), 20.2, 19.5, and 19.4 (all s,
PCHCH3), 18.3, 18.0, and 16.6 (all s, NCCH3). MS (FAB+): m/z
687 (M+).
P r ep a r a tion of [OsH{F ---HONdC(CH3)2}(tCCH2P h )-
(P iP r 3)2]BF 4 (10). A lilac solution of 4 (142 mg, 0.183 mmol)
in 12 mL of dichloromethane was treated with HBF4‚Et2O (30
µL, 0.220 mmol) and stirred for 2.5 h at room temperature
and then was filtered through Celite and evaporated to
dryness. Subsequent addition of dichloromethane (0.5 mL) and
diethyl ether (5 mL) caused the precipitation of a lilac solid,
which was washed with further portions of diethyl ether and
dried in vacuo. Yield: 90 mg (62%). Anal. Calcd for C27H61
-
BF5NOOsP2: C 41.91; H 7.95; N 1.81. Found: C 41.57; H 7.78;
N 2.0. IR (KBr, cm-1): ν(OH) 3210 (br), ν(OsH) 2174 (m), ν(CN)
1
1580 (s), ν(BF) 1050 (br). H NMR (300 MHz, CD2Cl2, 293 K):
δ 11.59 (d, J F-H ) 67.5 Hz, 1H, OH), 7.4-7.1 (m, 5H, Ph), 2.88
(br, 2H, OstCCH2), 2.49 and 2.32 (both s, 3H, NCCH3), 2.31
The protonation of complex 7 (15 mg, 0.022 mmol) in 0.5
mL of CD2Cl2 (1H NMR) or CH2Cl2 (2H NMR) in NMR tubes
with the stoichiometric amount of DBF4‚D2O (3 µL, 0.022
mmol) gives the complex [OsH{κ-N,κ-O[ONdC(CH3)2]}-
(tCCH2Ph)(PiPr3)2]BF4 with the CâH2 group partially deuter-
ated. After 10 min the 1H NMR spectrum indicates that the
protonation is quantitative. 2H NMR (46.03 MHz, CH2Cl2, 293
K): δ 2.89 (br, 1.7D, CD2Ph).
P r ep a r a tion of OsH{K-N,K-O[ONdC(CH3)2]}(dCdCH-
Cy)(P iP r 3)2 (8). This complex was prepared as described for
7 starting from 5 (83 mg, 0.106 mmol) and a solution of KOH
in methanol (1.1 mL, 0.212 mmol, 0.1888 N). A brown oil was
obtained. Yield: 30.0 mg (41%). IR (Nujol, cm-1): ν(OsH) 2091
(m), ν(CN) 1631 (s). 1H NMR (300 MHz, C6D6, 293 K, plus
hetcor): δ 2.65 (m, 6H, PCH), 2.6-0.9 (m, 11H, Cy), 2.10 and
1.98 (both s, 3H, NC(CH3)2), 1.42 and 1.36 (both dvt, N ) 12.9
Hz, J H-H ) 6.6 Hz, 18H, PCHCH3), 0.98 (s, 1H, OsdCdCH),
-8.49 (t, J H-P ) 17.4 Hz, 1H, OsH). 31P{1H} NMR (121.42
MHz, C6D6, 293 K): δ 22.26 (s). 13C{1H} NMR (75.42 MHz,
C6D6, 293 K, plus dept): δ 284.7 (t, J C-P ) 9.8 Hz, OsdC),
138.7 (s, NdC), 110.0 (s, OsdCdCHCy), 30.0 (s, primary
carbon atom of the cyclohexyl group), 38.4, 27.3, and 26.8 (all
s, secondary carbon atoms of the cyclohexyl group), 24.4 (vt,
N ) 23.3 Hz, PCH), 22.3 (s, NCCH3), 20.1 and 19.8 (both s,
PCHCH3), 18.1 (s, NCCH3). MS (FAB+): m/z 694 (M+ + H).
(m, 6H, PCH), 1.29 and 1.25 (both dvt, N ) 14.4 Hz, J H-H
)
7.2 Hz, 18H, PCHCH3), -6.66 (td, J P-H ) 16.5 Hz, J F-H ) 6.9
Hz, 1H, OsH). 31P{1H} NMR (121.42 MHz, CD2Cl2, 293 K): δ
36.62 (d, J F-P ) 39.0 Hz). 19F NMR (282.33 MHz, CD2Cl2, 293
K): δ -263.9 (dtd, J F-H ) 67.5 Hz, J F-P ) 39.0 Hz, J F-H ) 6.9
Hz, OsF), -154.6 (s, BF4). 13C{1H} NMR (75.42 MHz, CD2Cl2,
293 K, plus dept): δ 277.9 (dt, J C-F ) 109.5 Hz, J C-P ) 9.2
Hz, OstC), 163.3 (s, NdC), 129.9 and 129.6 (both s, Ph), 129.1
(s, CparaPh), 127.4 (s, CipsoPh), 57.9 (d, J C-F ) 11.5 Hz,
OstCCH2), 26.0 (s, NCCH3), 25.4 (vt, N ) 26.2 Hz, PCH), 19.8
(s, NCCH3), 19.1 and 18.7 (both s, PCHCH3). MS (FAB+): m/z
689 (M+ - F).
P r ep a r a tion of [OsH{F ---DONdC(CH3)2}(tCCH2P h )-
(P iP r 3)2]BF 4 (10-d 1). To solutions of 4 (15 mg, 0.019 mmol)
in 0.5 mL of CD2Cl2 (1H NMR) or CH2Cl2 (2H NMR) in NMR
tubes was added the stoichiometric amount of DBF4‚D2O (2.5
mL, 0.019 mmol). After 10 min the 1H NMR spectrum indicates
the quantitative formation of 10-d 1. 2H NMR (46.03 MHz, CH2-
Cl2, 293 K): δ 11.90 (d, J D-F ) 10 Hz, OD).
P r ep a r a tion of [OsH{F ---HONdC(CH3)2}(tCCH2Cy)-
(P iP r 3)2]BF 4 (11). This complex was prepared as described
for 10 starting from 116 mg (0.148 mmol) of 5 and HBF4‚Et2O
(24 µL, 0.178 mmol). A white solid was obtained. Yield: 102
mg (86%). Anal. Calcd for C29H63BF5NOOsP2: C 43.55; H 7.94;
N 1.75. Found: C 43.08; H 7.81; N 1.96. IR (KBr, cm-1): ν(OH)
3186 (br), ν(OsH) 2183 (m), ν(CN) 1654 (s), ν(BF) 1050 (br).
1H NMR (300 MHz, CD2Cl2, 293 K): δ 11.68 (d, J F-H ) 68.1
Hz, 1H, OH), 3.5-0.9 (m, 11H, Cy), 2.47 (m, 6H, PCH), 2.43
and 2.32 (both s, 3H, NCCH3), 1.54 (br, 2H, OstCCH2), 1.35
and 1.34 (both dvt, N ) 14.2 Hz, J H-H ) 7.0 Hz, 18H,
PCHCH3), -6.98 (td, J P-H ) 17.1 Hz, J F-H ) 6.6 Hz, 1H, OsH).
31P{1H} NMR (121.42 MHz, CD2Cl2, 293 K): δ 35.90 (d, J F-P
) 38.1 Hz). 19F NMR (282.33 MHz, CD2Cl2, 293 K): δ -265.9
(dtd, J F-H ) 68.1 Hz, J F-P ) 38.1 Hz, J F-H ) 6.6 Hz, OsF),
-155.2 (s, BF4). 13C{1H} NMR (75.42 MHz, CD2Cl2, 293 K, plus
dept): δ 283.9 (dt, J C-F ) 109.1 Hz, J C-P ) 8.7 Hz, OstC),
163.3 (s, NdC), 59.3 (d, J C-F ) 10.6 Hz, OstCCH2), 35.2
(s, primary carbon atom of the cyclohexyl group), 33.6, 25.8,
and 25.6 (all s, secondary carbon atoms of the cyclohexyl
group), 25.6 (vt, N ) 24.4 Hz, PCH), 25.4 and 19.9 (both s,
NCCH3), 19.3 and 18.7 (both s, PCHCH3). MS (FAB+): m/z
694 (M+ - HF).
P r ep a r a tion of OsH{K-N,K-O[ONdC(CH3)2]}(dCdCH-
tBu )(P iP r 3)2 (9). This complex was prepared as described for
7 starting from 6 (210 mg, 0.279 mmol) and a solution of KOH
in methanol (2.9 mL, 0.558 mmol, 0.1888 N). A yellow solid
was obtained. Yield: 90.0 mg (48%). Anal. Calcd for C27H59
-
NOOsP2: C 48.70; H 8.93; N 2.10. Found: C 48.35; H 8.67; N
2.28. IR (KBr, cm-1): ν(OsH) 2080 (m), ν(CN) 1628 (s). 1H NMR
(300 MHz, C6D6, 293 K, plus hetcor): δ 2.67 (m, 6H, PCH),
2.11 and 2.01 (both s, 3H, NCCH3), 1.43 (dvt, N ) 12.7 Hz,
J H-H ) 6.6 Hz, 18H, PCHCH3), 1.41 (s, 9H, C(CH3)3), 1.34 (dvt,
N ) 12.7 Hz, J H-H ) 6.6 Hz, 18H, PCHCH3), 0.71 (s, 1H, Osd
CdCH), -8.70 (t, J H-P ) 17.3 Hz, 1H, OsH). 31P{1H} NMR
(121.42 MHz, C6D6, 293 K): δ 20.65 (s). 13C{1H} NMR (75.42
MHz, C6D6, 293 K, plus apt): δ 284.1 (t, J C-P ) 8.3 Hz, Osd
C), 139.1 (s, NdC), 115.9 (s, OsdCdCHtBu), 33.7 (s, C(CH3)3),
24.6 (s, C(CH3)3), 24.4 (vt, N ) 23.0 Hz, PCH), 22.4 (s, NCCH3),
20.3 and 19.9 (both s, PCHCH3), 18.4 (s, NCCH3). 1H NMR
(300 MHz, C7D8, 218 K): δ 2.55 and 2.47 (both m, 6H, PCH),
2.00 (s, 6H, NC(CH3)2), 1.94 and 1.79 (both s, 3H, NCCH3),
1.39 (s, 9H, C(CH3)3) 1.4-1.1 (m, 72H, PCHCH3), 1.2 (s, 9H,
C(CH3)3), 1.41 (s, 9H, C(CH3)3), 0.71 and 0.66 (both s, 1H, Osd
P r ep a r a tion of [OsH{F ---HONdC(CH3)2}(tCCH2tBu )-
(P iP r 3)2]BF 4 (12). This complex was prepared as described
for 10 starting from 115 mg (0.152 mmol) of 6 and HBF4‚Et2O
(25 µL, 0.183 mmol). A white solid was obtained.Yield: 55.9
mg (66%). Anal. Calcd for C27H61BF5NOOsP2: C 41.91; H 7.95;
N 1.81. Found: C 41.57; H 7.78; N 2.00. IR (KBr, cm-1): ν(OH)
3218 (br), ν(OsH) 2176 (m), ν(CN) 1578 (s), ν(BF) 1050 (br).
1H NMR (300 MHz, CD2Cl2, 293 K): δ 11.64 (d, J F-H ) 68.7
Hz, 1H, OH), 2.48 (m, 6H, PCH), 2.45 and 2.32 (both s, 3H,
NCCH3), 1.69 (br, 2H, OstCCH2), 1.35 (dvt, N ) 14.1 Hz, J H-H
) 7.0 Hz, 36H, PCHCH3), 1.04 (s, 9H, C(CH3)3), -7.07 (td, J P-H
) 18.0 Hz, J F-H ) 6.6 Hz, 1H, OsH). 31P{1H} NMR (121.42
MHz, CD2Cl2, 293 K): δ 33.97 (d, J F-P ) 39.0 Hz). 19F NMR
CdCH), -8.49 (t, J H-P ) 16.5 Hz, 1H, OsH), -8.96 (t, J H-P
)
18.0 Hz, 1H, OsH). 31P{1H} NMR (121.42 MHz, C7D8, 218 K):
δ 21.5 and 18.4 (both s). 13C{1H} NMR (75.42 MHz, C7D8, 218
K): δ 284.2 (t, J C-P ) 10.5 Hz, OsdC), 283.6 (t, J C-P ) 7.9 Hz,
OsdC),139.3 and 139.1 (both s, NdC), 116.2 and 114.5 (both
s, OsdC)CHtBu), 33.8 and 33.5 (both s, C(CH3)3), 24.9 and
24.6 (both s, C(CH3)3), 24.4 and 23.9 (both vt, N ) 26.3 Hz,
PCH), 22.9 and 22.5 (both s, NCCH3), 20.3, 19.6, and 19.1 (all
s, PCHCH3), 18.3 and 17.9 (both s, NCCH3). MS (FAB+): m/z
668 (M+ + H).

Osmium-Elongated Dihydrogen Complex
Organometallics, Vol. 21, No. 12, 2002 2503
Ta ble 4. Cr ysta llogr a p h ic Da ta a n d Str u ctu r e Refin em en t for
[OsH{K-N,K-O[ONdC(CH3)2]}(tCCH2P h )(P iP r 3)2]BF 4 (4), OsH{K-N,K-O[ONdC(CH3)2]}(dCdCHP h )(P iP r 3)2 (7),
a n d [OsH{F ---HONdC(CH3)2}(tCCH2Cy)(P iP r 3)2]BF 4 (11)
4
7
11
formula
M
C
29H56BF4NOOsP2
C29H55NOOsP2
685.88
C29H63BF5NOOsP2
799.75
773.70
space group
a, Å
b, Å
monoclinic, P21/c
11.539(2)
11.930(2)
25.261(4)
triclinic, P1h
10.385(2)
10.9978(19)
13.967(3)
97.471(4)
95.572(4)
93.851(3)
1569.1(5)
2
monoclinic, C2/c
19.6481(11)
12.8849(11)
28.644(2)
c, Å
R, deg
â, deg
γ, deg
V, Å3
Z
90
90
96.029(3)
90
3458.2(9)
4
1.486
296.0(2)
3.823
4-56
91.301(2)
90
7249.7(9)
8
1.465
173.0(2)
3.654
4-56
F
calc, g cm-3
T, K
1.452
173.0(2)
4.186
µ, mm-1
2θ range data collect, deg
index ranges
4-56
h: -15, 14; k: -15, 15; l: -32, 33
28 542
h: -13, 13; k: -14, 14; l: -18, 18
h: -26, 20; k: -17, 17; l: -38, 38
28 069
no. of measd reflns
no. of data/params/restraints
R(F) [F2 > 2σ(F2)]a
wR(F2) [all data]b
S [all data]d
19 579
8299/357/3
0.0536
7496/329/0
0.0468
8715/388/0
0.0356
0.0964c
0.794
0.1110c
0.956
0.0573c
0.773
R(F) ) ∑||Fo| - |Fc||/∑|Fo|. wR(F2) ) (∑[w(Fo - Fc2)2/∑[w(Fo2)2])1/2
.
c w ) 1/[σ2(Fo2) + (aP)2 + bP] with P ) (Fo + 2Fc2)/3; a ) 0.0198
a
b
2
2
and b ) 0 for 4, and a ) 0.0613 and b ) 0 for 7, and a ) 0.0107 and b ) 0 for 11. S ) [∑(Fo - Fc2)2]/(n - p), n ) number of reflections,
p ) number of parameters.
d
2
(282.33 MHz, CD2Cl2, 293 K): δ -261.1 (dtd, J F-H ) 68.7 Hz,
J F-P ) 39.0 Hz, J F-H ) 6.6 Hz, OsF), -155.3 (s, BF4). 13C{1H}
NMR (75.42 MHz, CD2Cl2, 253 K): δ 284.1 (dt, J C-F ) 111.6
Hz, J C-P ) 7.5 Hz, OstC), 163.0 (s, NdC), 65.2 (d, J C-F ) 9.6
Hz, OstCCH2), 32.3 (s, C(CH3)3), 30.0 (s, C(CH3)3), 25.2 (vt,
N ) 25.1 Hz, PCH), 25.1 and 20.1 (both s, NCCH3), 19.3 and
18.5 (both s, PCHCH3). MS (FAB+): m/z 668 (M+ - HF).
X-r a y Str u ctu r e An a lysis of Com p lexes 4, 7, a n d 11. A
summary of crystal data and refinement parameters for 4, 7,
and 11 is given in Table 4. Suitable crystals for X-ray
diffraction were obtained by slow diffusion of diethyl ether into
a saturated solution of 4 and 11 in CH2Cl2, or methanol into
a saturated solution of 7 in toluene. Diffraction data were
recorded at room temperature (4) or 173(2) K (7 and 11) on a
Bruker Smart Apex diffractometer with a CCD area detector,
using graphite-monocromated Mo KR radiation (λ ) 0.71073
Å) operating at 50 kV, 35 mA for 4 and 11 or 50 kV, 40 mA for
7. Frames of data were collected over a hemisphere for 4 and
11 or over the complete sphere for 7 with scan widths of 0.3°
in ω and exposure times of 10 s/frame.
techniques and refined by full-matrix least-squares on F2
(SHELXL9747) first with isotropic and then with anisotropic
displacement parameters for the non-hydrogen atoms of non-
disordered groups. Organic hydrogen atoms were introduced
in calculated positions or located in a difference Fourier map
and refined riding on the corresponding carbon atoms. Hydride
ligands were refined as free isotropic atoms. Scattering factors
corrected for anomalous dispersion were as implemented in
the refinement program.
Ackn owledgm en t. Financial support from the DGES
of Spain (Project PB98-1591, Programa de Promocio´n
General de Conocimiento) is acknowledged. P.B. thank
the “Ministerio de Educacio´n, Cultura 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.
Data were corrected for absorption with the SADABS
routine, based on the method of Blessing,45 integrated in the
Bruker SAINT program.46 The structures were solved by
the Patterson method (SHELXS9747) and difference Fourier
OM0200656
(46) SAINT+, version 6.1; Bruker AXS, Inc.: Madison, WI, 2000.
(47) Sheldrick, G. M. SHELXS97; University of Go¨ttingen: Ger-
many, 1997.
(45) Blessing, R. H. Acta Cystallogr., Sect. A 1995, 51, 33.