Oxidative Addition of Group 14 Element Hydrido Compounds to OsH2(η2-CH2=CHEt)-(CO)(PiPr 3)2: Synthesis and Characterization of the First Trihydrido-Silyl, Trihydrido-Germyl, and Trihydrido-Stannyl Derivatives of Osmium(IV)

Article abstract of DOI:10.1021/ic9509591

The dihydrido-olefin complex OsH₂(η²-CH₂=CHEt)(CO)(P¹Pr ₃)₂ (2) reacts with H₂SiPh₂ to give OsH₃(SiHPh₂)-(CO)(P¹Pr₃)₂ (3). The molecular structure of 3 has been determined by X-ray diffraction (monoclinic, space group P2₁/c with a = 16.375(2) A?, b = 11.670(1) A?, c =18.806(2) A?, β= 107.67(1)°, and Z = 4) together with ab initio calculations on the model compound OsH₃(SiH₃)(CO)(PH₃)₂. The coordination geometry around the osmium center can be rationalized as a heavily distorted pentagonal bipyramid with one hydrido ligand and the carbonyl group in the axial positions. The two other hydrido ligands lie in the equatorial plane, one between the phosphine ligands and the other between the SiHPh₂ group and one of the phosphine ligands. Complex 3 can also be prepared by reaction of OsH(η²-H₂BH₂)(CO)(P¹Pr ₃)₂ (4) with H₂SiPh₂. Similarly, the treatment of 4 with HSiPh₃ affords OsH₃(SiPh₃)(CO)(P¹Pr₃)₂ (5), while the addition of H₃SiPh to 4 in methanol yields OsH₃{Si(OMe)₂-Ph}(CO)(PⁱPr₃) ₂ (6). Complex 2 also reacts with HGeR₃ and HSnR₃ to give OsH₃(GeR₃)(CO)(PⁱPr₃)2 (GeR₃ = GeHPh₂ (7), GePh₃ (8), GeEt₃ (9)) and OsH₃(SnR₃)(CO)(PⁱPr₃)₂ (R = Ph (10), ⁰Bu (11)), respectively. In solution, compounds 3 and 5-11 are fluxro?nal and display similar ¹H and ³¹P{¹H} NMR spectra, suggesting that they possess a similar arrangement of ligands around the osmium atom.

Full text of DOI:10.1021/ic9509591

1250
Inorg. Chem. 1996, 35, 1250-1256
Oxidative Addition of Group 14 Element Hydrido Compounds to OsH2(η2-CH2dCHEt)-
(CO)(PiPr3)2: Synthesis and Characterization of the First Trihydrido-Silyl,
Trihydrido-Germyl, and Trihydrido-Stannyl Derivatives of Osmium(IV)
Mar´ıa L. Buil,† Pablo Espinet,‡ Miguel A. Esteruelas,*,† Fernando J. Lahoz,† Agust´ı Lledo´s,§
Jesu´s M. Mart´ınez-Ilarduya,‡ Feliu Maseras,§ Javier Modrego,† Enrique On˜ate,† Luis A. Oro,†
Eduardo Sola,† and Cristina Valero†
Departamento de Qu´ımica Inorga´nica, Instituto de Ciencia de Materiales de Arago´n, Universidad de
Zaragoza, CSIC, 50009 Zaragoza, Spain, Departamento de Qu´ımica Inorga´nica, Facultad de Ciencias,
Universidad de Valladolid, 47005 Valladolid, Spain, and Unitat de Qu´ımica F´ısica, Departament de
Qu´ımica, Universitat Auto`noma de Barcelona, 08193 Bellaterra, Barcelona, Spain
ReceiVed July 28, 1995X
The dihydrido-olefin complex OsH2(η2-CH2dCHEt)(CO)(PiPr3)2 (2) reacts with H2SiPh2 to give OsH3(SiHPh2)-
(CO)(PiPr3)2 (3). The molecular structure of 3 has been determined by X-ray diffraction (monoclinic, space
group P21/c with a ) 16.375(2) Å, b ) 11.670(1) Å, c )18.806(2) Å, â ) 107.67(1)°, and Z ) 4) together with
ab initio calculations on the model compound OsH3(SiH3)(CO)(PH3)2. The coordination geometry around the
osmium center can be rationalized as a heavily distorted pentagonal bipyramid with one hydrido ligand and the
carbonyl group in the axial positions. The two other hydrido ligands lie in the equatorial plane, one between the
phosphine ligands and the other between the SiHPh2 group and one of the phosphine ligands. Complex 3 can
also be prepared by reaction of OsH(η2-H2BH2)(CO)(PiPr3)2 (4) with H2SiPh2. Similarly, the treatment of 4 with
HSiPh3 affords OsH3(SiPh3)(CO)(PiPr3)2 (5), while the addition of H3SiPh to 4 in methanol yields OsH3{Si(OMe)2-
Ph}(CO)(PiPr3)2 (6). Complex 2 also reacts with HGeR3 and HSnR3 to give OsH3(GeR3)(CO)(PiPr3)2 (GeR3 )
GeHPh2 (7), GePh3 (8), GeEt3 (9)) and OsH3(SnR3)(CO)(PiPr3)2 (R ) Ph (10), nBu (11)), respectively. In solution,
1
compounds 3 and 5-11 are fluxional and display similar H and 31P{1H} NMR spectra, suggesting that they
possess a similar arrangement of ligands around the osmium atom.
OsHCl(CO)(PiPr3)2 + HSiEt3 f
Introduction
OsH2(SiEt3)Cl(CO)(PiPr3)2 u
The fact that the 5d metals form stronger bonds than their
3d and 4d counterparts with the ligands typically involved in
catalytic transformations has led in the past to the general
Os(SiEt3)Cl(η2-H2)(CO)(PiPr3)2 (1)
assumption that reactions involving third-row transition metal
basic knowledge of the leading factors of the catalytic cycles,
complexes are too slow for catalytic cycles and are thus of no
that is, the elementary steps of the catalysis. Therefore, in
practical use in catalysis. Over the last few years, a number of
connection with the hydrosilylation reactions, the additions of
interesting examples of organic transformations catalyzed by
silanes, and, in general, of group 14 element hydrido compounds
third-row transition metal complexes have emerged in the
to transition metal hydrido complexes are elementary reactions
literature, indicating that a judicious choice of the metal-ligand
of considerable interest.5,6
system may also lead to active third-row catalysts.1 In this
We recently reported that the reaction of the five-coordinated
respect, we have reported examples, from the iron triad, which
show that not only iron and ruthenium but also osmium form
complexes which behave as good catalysts for the addition of
hydrido-carbonyl complex 1 with nBuLi affords the dihydrido
complex OsH2(η2-CH2dCHEt)(CO)(PiPr3)2 (2).7 Continuing
our study on the interaction of osmium-hydrido complexes with
potentially useful molecules in catalysis, we have investigated
the addition of group 14 element hydrido compounds to the
dihydrido OsH2(η2-CH2dCHEt)(CO)(PiPr3)2 (2). During this
study, we have isolated complexes of general formula OsH3(ER3)-
(CO)(PiPr3)2 (E ) Si, Ge, Sn). Compounds of the type MLnH3-
(ER3) are relatively scarce in the iron triad. Schubert et al.8,9a
have described the synthesis and the spectroscopic properties
of the iron-trihydrido-silyl complexes FeH3(SiR3)(PR3)3 and
silanes to terminal alkynes.2-4 Thus, the five coordinate
hydrido-carbonyl complex OsHCl(CO)(PiPr3)2 (1) was found
to be a very active and highly selective catalyst for the addition
of triethylsilane to phenylacetylene. The catalytic reaction
proceeds via the silyl-dihydrogen intermediate Os(SiEt3)Cl(η2-
H2)(CO)(PiPr3)2, which is formed according to eq 1.2
The design of new catalysts and new processes requires a
† Universidad de Zaragoza, CSIC.
‡ Universidad de Valladolid.
§ Universitat Auto`noma de Barcelona.
(5) Ojima, I. The Chemistry of Organic Silicon Compounds; Patai, S.,
Rappoport, Z., Eds.; Wiley: New York, 1989; Chapter 25.
(6) Esteruelas, M. A.; Lahoz, F. J.; Oliva´n, M.; On˜ate, E.; Oro, L. A.
Organometallics 1995, 14, 3486.
(7) Albe´niz, M. J.; Buil, M. L.; Esteruelas, M. A.; Lo´pez, A. M.; Oro, L.
A.; Zeier, B. Organometallics 1994, 13, 3746.
X Abstract published in AdVance ACS Abstracts, January 15, 1996.
(1) Chaloner, P. A.; Esteruelas, M. A.; Joo, F.; Oro, L. A. Homogeneous
Hydrogenation; Kluwer Academic Publishers: Boston, MA, 1994.
(2) Esteruelas, M. A.; Oro, L. A.; Valero, C. Organometallics 1991, 10,
462.
(3) Esteruelas, M. A.; Lo´pez, A. M.; Oro, L. A.; Tolosa, J. I. J. Mol.
Catal. A: Chem. 1995, 96, 21.
(4) Sa´nchez-Delgado, R. A.; Rosales M.; Esteruelas, M. A.; Oro, L. A. J.
Mol. Catal. A: Chem. 1995, 96, 231.
(8) Knorr, M.; Gilbert, S.; Schubert, U. J. Organomet. Chem. 1988, 347,
C17.
(9) (a) Schubert, U.; Gilbert, S.; Mock, S. Chem. Ber. 1992, 125, 835.
(b) Procopio, L. J.; Berry, D. H. J. Am. Chem. Soc. 1991, 113, 4039.
0020-1669/96/1335-1250$12.00/0 © 1996 American Chemical Society

Oxidative Addition to OsH2(η2-CH2dCHEt)(CO)(PiPr3)2
Inorganic Chemistry, Vol. 35, No. 5, 1996 1251
1
1
Figure 1. Variable-temperature 300-MHz H NMR spectra in the high-field region of OsH3(SiHPh2)(CO)(PiPr3)2 (3) in toluene-d8: (a) H; (b)
1H{31P}; (c) simulated.
FeH3(SiR3)(CO)(dppe) (dppe ) Ph2PCH2CH2PPh2) and the
iron-trihydrido-stannyl derivatives FeH3(SnR3)(PR3)3, which
have a pseudotetrahedral heavy-atom skeleton. The same
skeleton has been found in the ruthenium-trihydrido-silyl
compound RuH3(SiMe3)(PMe3)3.9 Related ruthenium-tri-
hydrido-silyl derivatives have also been synthetized by Kono
et al.,10 Haszeldine et al.,11 and Caulton et al.12 As far as we
know, ruthenium-trihydrido-stannyl and iron- and ruthenium-
trihydrido-germyl complexes have yet to be reported.
In this paper we report the synthesis and characterization of
the first trihydrido-silyl, trihydrido-germyl, and trihydrido-
stannyl compounds of osmium. Moreover, the trihydrido-
germyl complexes are also the first examples of compounds of
this type in the iron triad.
Figure 2. 1H NMR spectra in the high-field region of OsH3-
1
1
(SiHPh2)(CO)(PiPr3)2 (3) in toluene-d8: (a) H {1H }; (b) H.
Results and Discussion
The 1H and 31P{1H} NMR spectra are temperature dependent.
Figure 1 shows the 1H and 1H{31P} NMR spectra in the hydrido
region as a function of the temperature. At 193 K the 1H{31P}
NMR spectrum (Figure 1b) shows a singlet at -11.18 ppm and
another apparent singlet at -9.11 ppm, with a relative intensity
ratio of 1:2. These signals are split into a triplet with a P-H
coupling constant of 15 Hz and into the AB part of a second
order ABXY splitting pattern (Figure 1a) as a result of the P-H
coupling. When the temperature is raised, both resonances
coalesce to give finally a triplet at 355 K. At 193 K, the 31P-
{1H} NMR spectrum shows a broad resonance between 35 and
39 ppm. The spectra of Figure 1 suggest that complex 3 has a
rigid structure only at low temperature. In this structure the
hydrido ligands are chemically inequivalent, and one of them
is not coupled with the other two, as is proved by Figure 2,
which shows that irradiation of the signal at -11.18 ppm leaves
unaffected that at -9.11 ppm.
Silyl Derivatives. The dihydrido-1-butene complex OsH2(η2-
CH2dCHEt)(CO)(PiPr3)2 (2) reacts with 2 equiv of H2SiPh2 in
hexane to give a colorless solution, from which the trihydrido-
silyl complex OsH3(SiHPh2)(CO)(PiPr3)2 (3) was isolated as a
white solid in 75% yield.
In the IR spectrum of 3 in Nujol, the most noticeable
absorptions are those corresponding to the vibrations ν(Si-H),
ν(Os-H), and ν(CO), which appear at 2075, 1995, and 1890
cm-1, respectively. At room temperature, the 1H NMR
spectrum shows the expected resonances for the triisopropyl-
phosphine ligands and the phenyl groups of the diphenylsilyl
ligand, along with a triplet at 6.52 ppm (JP-H ) 12.1 Hz)
assigned to the Si-H proton, and a broad resonance at -9.65
ppm due to the three hydrido ligands. The 31P{1H} NMR
spectrum contains a singlet at 37.3 ppm.
(10) Kono, H.; Wakao, N.; Ito, K.; Nagai, V. J. Organomet. Chem. 1977,
132, 53.
In order to determine the structure of 3, an X-ray diffraction
experiment on a single crystal of this compound was carried
out. Unfortunately, from the X-ray diffraction study, it was
not possible to locate the hydrido positions. Figure 3 shows a
(11) Haszeldine, R. N.; Malkin, L. S.; Parish, R. V. J. Organomet. Chem.
1979, 182, 323.
(12) Poulton, J. T.; Sigalas, M. P.; Eisenstein, O.; Caulton, K. G. Inorg.
Chem. 1993, 32, 5490.

1252 Inorganic Chemistry, Vol. 35, No. 5, 1996
Buil et al.
Figure 3. Molecular diagram of complex 3.
Table 1. Selected Bond Lengths (Å) and Angles (deg) for the
Complex OsH3(CO)(SiHPh2)(PiPr3)2 (3)
Os-P(1)
Os-P(2)
Os-Si
2.362(2)
2.389(2)
2.448(2)
Os-C(1)
C(1)-O
1.916(9)
1.142(11)
Figure 4. MP2 optimized structure of complex OsH3(SiH3)(CO)(PH3)2.
Table 2. Most Important Optimized Geometrical Parametersa of the
Complex OsH3(SiH3)(CO)(PH3)2
P(1)-Os-P(2)
P(1)-Os-Si
P(1)-Os-C(1)
P(2)-Os-Si
P(2)-Os-C(1)
Si-Os-C(1)
Os-Si-C(20)
146.06(7)
117.91(7)
96.8(3)
91.23(7)
89.7(2)
107.7(2)
117.2(3)
Os-Si-C(26)
Os-Si-H(04)
C(20)-Si-C(26)
C(20)-Si-H(04)
C(26)-Si-H(04)
Os-C(1)-O
115.0(3)
110(2)
105.5(3)
102(2)
105(2)
178.1(7)
Os-P(1)
Os-P(2)
Os-Si
Os-C(1)
C(1)-O
Os-H(1)
Os-H(2)
Os-H(3)
2.362
2.388
2.448
1.916
1.142
1.685
1.668
1.655
H(1)‚‚‚H(3)
H(2)‚‚‚H(1)
H(2)‚‚‚H(3)
Si‚‚‚H(1)
2.459
2.217
3.227
2.528
3.981
1.869
Si‚‚‚H(2)
Si‚‚‚H(3)
view of the skeleton of the molecule. Selected bond distances
and angles are listed in Table 1.
The heavy atom skeleton of 3 can be described as a distorted
trigonal pyramid with the carbonyl ligand in the axial site. The
silicon and both phosphorus atoms are at the base sites, with
the silicon and one of the two phosphorus atoms bent away
from the axial ligand (P(1)-Os-C(1) ) 96.8(3)°, Si-Os-C(1)
) 107.7(2)°). The angles between the basal ligands are P(1)-
Os-P(2) ) 146.06(7)°, P(1)-Os-Si ) 117.91(7)°, and P(2)-
Os-Si ) 91.23(7)°.
P(1)-Os-P(2)
P(1)-Os-Si
P(1)-Os-C(1)
P(1)-Os-H(1)
P(1)-Os-H(2)
P(1)-Os-H(3)
P(2)-Os-Si
P(2)-Os-C(1)
P(2)-Os-H(1)
P(2)-Os-H(2)
P(2)-Os-H(3)
146.1
C(1)-Os-H(2)
Si-Os-C(1)
96.2
107.6
72.8
150.1
49.7
178.1
86.9
82.7
94.8
152.3
117.9
96.7
84.5
75.4
70.7
91.2
89.8
88.4
70.7
136.9
Si-Os-H(1)
Si-Os-H(2)
Si-Os-H(3)
C(1)-Os-H(1)
C(1)-Os-H(3)
H(1)-Os-H(2)
H(1)-Os-H(3)
H(2)-Os-H(3)
Theoretical studies with geometry optimization have proved
to be efficient locating hydrido positions in transition metal
complexes.13 For example, the full structural determination of
the complex ReH2(SiHPh2)(CO)(PMe2Ph)3, for which only the
position of the heavy atoms were determined by X-ray diffrac-
tion, was achieved by means of ab initio calculations.14 With
this precedent in mind, we have carried out ab initio calculations
at the MP2 level, in order to locate the hydrido positions in
complex 3. For this purpose the triisopropylphosphine and
diphenylsilyl ligands were replaced by PH3 and SiH3, respec-
tively. The positions of the heavy atoms were fixed at the values
determined by X-ray diffraction, and energy gradient optimiza-
tion techniques were used to find the position of the hydrido
ligands. Different starting geometries were tested, all converg-
ing to the same structure. Figure 4 presents this optimized
structure, and Table 2 summarizes the most significant geo-
metrical parameters.15
a Distances in Å, angles in deg. Heavy atoms fixed at the positions
found in the X-ray determined values of OsH3(SiHPh2)(CO)(PiPr3)2.
tions in the OsP2CSi core. Thus, one of the hydrido ligands is
trans to the carbonyl group (C(1)-Os-H(1) ) 178.1°), while
the others lie between P(1) and P(2) (H(2)) and between P(1)
and Si (H(3)).
The hydrogen-hydrogen separations between the hydrido
ligands (more than 2.2 Å) and the T1 values shown in Figure 1
rule out the possibility of the existence of a dihydrogen ligand.
However, the eventual presence of an η2-HSiR3 group is more
arguable. The hydrido ligand H(3) is near the silicon atom (Si-
H(3) ) 1.869 Å) but with a very elongated distance, compared
to the normal Si-H bond length (1.48 Å). The Si-H distances
in compounds formulated as η2-HSiR3 are in the range 1.7-
1.8 Å,16 and in general their structures resemble more closely
those of oxidative addition products than those of σ complexes
with an unstretched Si-H bond.17 The bond angles in the model
compound OsH3(SiH3)(CO)(PH3)2 (Table 2) can be hardly
assigned to an octahedron as should correspond to the presence
of an η2-HSiR3 ligand. On the contrary, all the geometrical
parameters are more consistent with heptacoordination around
In agreement with the 1H NMR spectrum of 3 at 193 K, the
theoretical calculations localized the hydrido ligands in chemi-
cally inequivalent positions, which correspond to vacant posi-
(13) Lin, Z.; Hall, M. B. Coord. Chem. ReV. 1994, 135/136, 845 and
references cited therein.
(14) Lin, Z.; Hall, M. B. Inorg. Chem. 1991, 30, 2569.
(15) A full geometry optimization of complex OsH3(SiH3)(CO)(PH3)2
yielded a very similar geometry to that obtained with the frozen heavy-
atom skeleton, differences being smaller than 0.05 Å in the bond
distances and 5° in the bond angles.
(16) Schubert, U. AdV. Organomet. Chem. 1990, 30, 151.
(17) Crabtree, R. H. Angew. Chem., Int. Ed. Engl. 1993, 32, 789.

Oxidative Addition to OsH2(η2-CH2dCHEt)(CO)(PiPr3)2
Inorganic Chemistry, Vol. 35, No. 5, 1996 1253
Scheme 1
the metal atom. Moreover the angles between the metal, the
silicon atom, and the silyl hydrogens (H(10), H(11), and H(12))
are roughly tetrahedral (between 109 and 117°), whereas the
angles between H(3), Si, and the silyl hydrogens deviate much
more from the tetrahedral ones (H(3)-Si-H(12) ) 151.5°). The
environment of the silicon atom of 3 is also tetrahedral with
bond angles between 117.1(2) and 102(2)° (Table 1). In
addition, it should be mentioned that for hydrido-diphenylsilyl
compounds, there exists a relationship between the C-Si-C
angle of the diphenylsilyl ligand and the extent of the oxidative
the CO group and the H(1) hydrido ligand. If it were a regular
PB, the other five ligands (P(1), P(2), H(2), H(3), and Si) would
lie in the equatorial plane, with interequatorial ligand angles of
72 and 144°. Taking XY as the equatorial plane, the P(2) and
H(3) ligands are in the plane (Z ) 0.01 and 0.09 Å, respec-
tively), H(2) and P(1) are slightly bent away from this plane (Z
) -0.18 and -0.28 Å, respectively) and the silicon atom is
far from the regular PB position (Z ) -0.75 Å). P(2)-Os-Si
and P(1)-Os-Si angles are 91.2 and 117.9°, respectively. An
alternative is to describe the model compound as a distorted
capped trigonal prism, with H(2) as a capping ligand, P(1), P(2),
H(1), and C (from CO) atoms forming the capped quadrilateral
face, and Si and H(3) forming the edge of the CTP. However,
as it corresponds to different bond lengths, the four ligands of
the quadrilateral face are not in a plane. The dihedral angle
between the planes P(1)-P(2)-H(1) and P(2)-H(1)-C is 28.8°.
Therefore, we think it is more reasonable to describe the
coordination polyhedron of the model compound OsH3(SiH3)-
(CO)(PH3)2, and consequently of 3, as a heavily distorted
pentagonal bipyramid.
Complex 3 can also be obtained by reaction of the octahedral
compound OsH(η2-H2BH2)(CO)(PiPr3)2 (4) with H2SiPh2 in
methanol as solvent (Scheme 1). Through this route, complex
3 was isolated in 70% yield. Similarly, the treatment of 4 with
HSiPh3 affords OsH3(SiPh3)(CO)(PiPr3)2 (5), while the addition
of H3SiPh to a suspension of 4 in methanol yields OsH3{Si-
(OMe)2Ph}(CO)(PiPr3)2 (6), containing a dialkoxysilyl ligand.
The (dialkoxysilyl)iridium (III) compounds IrH2{Si(OR)2Ph}-
(CO)2(PCy3) (R ) Me, Et, iPr) have been recently prepared by
a similar procedure.24 Previously, Caulton and co-workers had
reported that the reaction of Cp*Ru(PiPr2Ph)(OCH2CF3) with
H2SiPh2 gives two products, one of which is the alkoxysilyl
derivative Cp*Ru(PiPr2Ph)H2{Si(OCH2CF3)Ph2}.25
addition. Thus, for the complexes IrH2(SiHPh2)(PMe3)318 and
19
RuH(SiHPh2)(CO)(PtBu2Me)2
the angles C-Si-C are
102.5(4) and 102.5(3) Å, respectively, and the Si-H has been
fully oxidatively added to the metal, whereas in the complexes
CrH(SiHPh2)(η6-C6Me6)(CO)2,20 Mn(η5-C5H4Me)(H)(SiHPh2)-
(CO)(PMe3), Mn(η5-C5Me5)(H)(SiHPh2)(CO)2,21 and Ti(η5-
C5H5)2(H)(SiHPh2)(CO)(PMe3)22 the related angles are
105.9(2), 106.4(2), 107.0(1), and 105.4(3)°, respectively, and
the Si-H bonds interact in an agostic fashion. For complex 3
the value of the angle C(20)-Si-C(26) determined by X-ray
diffraction is 105.4(3)°. On the basis of the above mentioned
considerations, we formulate complex 3 as a trihydrido-silyl-
osmium (IV) derivative, although possibly with some residual
Si-H interaction.
Having formulated complex 3 as a heptacoordinate osmium
derivative, we can try to relate its structure, on the basis of the
theoretical calculations, to the most common regular polyhedra
found in seven-coordinate molecules: pentagonal bipyramid
(PB), capped octahedron (CO), and capped trigonal prism
(CTP).23 None of these three ideal coordination polyhedra
reproduces accurately the bond angles presented in Tables 1
and 2. The most clear structural features of the model
compound OsH3(SiH3)(CO)(PH3)2 is the trans disposition of
Complexes 5 and 6 were isolated as white solids in 75 and
65% yield, respectively. In the IR spectra in Nujol the ν(Os-
H) and ν(CO) absorptions appear at 2000 (5 and 6), 1890 (5),
and 1900 (6) cm-1. The spectrum of 6 also contains a strong
band at 1075 cm-1, which was assigned to the ν(Si-O)
vibration.24,26 The 1H and 31P{1H} NMR spectra of these
(18) Zarate, E. A.; Kennedy, V. O.; McCune, J. A.; Simons, R. S.; Tessier,
C. A. Organometallics 1995, 14, 1802.
(19) Heyn, R. H.; Huffman J. C.; Caulton, K. G. New J. Chem. 1993, 17,
797.
(20) Schubert, U.; Mu¨ller, L.; Alt, H. G. Organometallics 1987, 6, 469.
(21) Schubert, U.; Scholz, G.; Mu¨ller, J.; Ackermann, K.; Wo¨rle, B.;
Stansfield, R. F. D. J. Organomet. Chem. 1986, 306, 303.
(22) Spaltenstein, E.; Palma, P.; Krentzer, K. A.; Willoughby, C. A.; Davis,
W. M.; Buchwald, S. L. J. Am. Chem. Soc. 1994, 116, 10308.
(23) (a) Muetterties, E. L.; Guggenberger, L. J. J. Am. Chem. Soc. 1974,
96, 1748. (b) Drew, M. G. B. Progr. Inorg. Chem. 1977, 23, 67. (c)
Hoffmann, R.; Beier, B. F.; Muetterties, E. L.; Rossi, A. R. Inorg.
Chem. 1977, 16, 511. (d) Kepert, D. L. Progr. Inorg. Chem. 1979,
25, 41.
(24) Esteruelas, M. A.; Lahoz, F. J.; Oliva´n, M.; On˜ate, E.; Oro, L. A.
Organometallics 1994, 13, 4246.
(25) Johnson, T. J.; Coan, P. S.; Caulton, K. G. Inorg. Chem. 1993, 32,
4594.
(26) Esteruelas, M. A.; Nu¨rnberg, O.; Oliva´n, M.; Oro, L. A.; Werner, H.
Organometallics 1993, 12, 3264.

1254 Inorganic Chemistry, Vol. 35, No. 5, 1996
Buil et al.
compounds show a dependence on temperature similar to that
previously described for 3. At room temperature, the 1H NMR
spectrum of 5 in the hydrido region shows a broad resonance
centered at -9.76 ppm. At 193 K this resonance is converted
into a triplet at -9.39 ppm, with a P-H coupling constant of
20.5 Hz, and the AB part of a second-order ABXY splitting
1
pattern centered at -9.92 ppm. At room temperature, the H
NMR spectrum of 6 in the high field region shows a triplet at
-10.89 ppm with a P-H coupling constant of 8.8 Hz, while at
193 K, it contains again a new triplet at -10.04 ppm, with a
P-H coupling constant of 20.0 Hz and the AB part of a second-
order ABXY splitting pattern centered at -10.95 ppm. At room
temperature, the 31P{1H} NMR spectra show singlets at 24.6
(5) and 30.0 (6) ppm. At 193 K, these singlets are broad. The
above-mentioned spectroscopic data suggest that 5 and 6 present
a coordination polyhedron around the osmium atom similar to
3.
Germyl and Stannyl Derivatives. The dihydrido-olefin
complex 2 also reacts with H2GePh2, HGePh3, and HGeEt3 to
give the corresponding trihydrido-germyl derivatives 7-9
according to eq 2.
Figure 5. Variable-temperature 300-MHz 1H NMR spectra in the high-
field region of OsH3(GeEt3)(CO)(PiPr3)2 (9) in toluene-d8.
under off-resonance conditions split into quartets due to the P-H
coupling. At 193 K, both singlets are broad.
Complex 2 also reacts with and HSnPh3 and HSnnBu3. The
products of the reactions are the trihydrido-stannyl derivatives
OsH3(SnPh3)(CO)(PiPr3)2 (10) and OsH3(SnnBu3)(CO)(PiPr3)2
(11), which are formed according to eq 3. We note that the
dihydride-distannyl complex OsH2(SnMe)2(CO)(PPh3)2 has
been previously synthetized, by oxidative addition of HSnMe3
to OsH(SnMe3)(CO)(PPh3)2.27
Complex 7 was isolated as a yellow oil in quantitative yield,
1
and characterized by H and 31P{1H} NMR spectroscopy. At
1
room temperature the H NMR spectrum in toluene-d8 shows
the expected resonances for the triisopropylphosphine ligands
and the phenyl groups of the diphenylgermyl ligand, along with
a triplet at 5.78 ppm, with a P-H coupling constant of 11.7
Hz, assigned to the Ge-H proton and a triplet at -9.80 ppm,
with a P-H coupling constant of 15 Hz. Below room
temperature, a broadening of the latter triplet is observed. The
variable temperature 300-MHz T1 study of the signal at -9.80
ppm gives a T1(min) of 270 ms at 253 K, in agreement with
the trihydrido character of 7. At room temperature the 31P-
{1H} NMR spectrum shows a singlet at 38.9 ppm, which
becomes broad at 193 K.
Complex 10 was isolated as a white solid in 75% yield, while
complex 11 was isolated as an orange oil in quantitative yield.
In the IR spectrum of 10, the most noticiable absorptions are
the ν(Os-H) and ν(CO) vibrations, which appear at 2080 and
1966 cm-1, respectively. In the high field region, the 1H NMR
spectra of both compounds are similar. At room temperature,
they show triplets at -9.90 (JP-H ) 15.1 Hz, 10) and -10.72
(JP-H ) 13.5 Hz, 11). Satellites due to the Sn isotopes are
also observed near these resonances. The values of the Sn-H
coupling constants are 52.2 (10) and 68.1 (11) Hz. Below room
temperature, a broadening of the triplets is observed. The triplet
of 10 gives finally, at 178 K, two broad resonances at about
-10 and -11 ppm with an intensity ratio of 1:2. At room
temperature the 31P{1H} NMR spectra show singlets at 39.3
(10) and 34.0 (11) ppm along with the satellites due to the Sn
isotopes, with P-Sn coupling constants of 69.5 (10) and 33.4
(11) Hz. Under off-resonance conditions, both singlets are split
into quartets due to the P-H coupling. At 193 K, both
resonances are broad.
Complexes 8 and 9 were isolated as white solids in 62 (8)
and 60% (9) yield. In the IR spectra in Nujol the ν(Os-H)
and ν(CO) absorptions appear at 1966 (8) and 1957 (9) and at
1867 (8) and 1870 (9) cm-1 respectively. The temperature
dependent behavior of the 1H NMR spectrum of 8 is as that of
7. At room temperature, the spectrum contains in the hydrido
region a triplet at -9.63 ppm (JP-H ) 15 Hz), which is broad
1
at 193 K. However, according to the H NMR spectrum 9
behaves in a manner similar to the dialkoxysilyl complex 6
(Figure 5). At room temperature the hydrido resonances appear
as only one broad triplet at -10.41 ppm. Below room
temperature, the signal broadens, to give finally at 193 K a triplet
at -11.20 ppm with a P-H coupling constant of 21 Hz, and
the AB part of a second order ABXY spin system centered at
-9.90 ppm. In this case, the variable temperature 300-MHz
T1 study rules out also the possibility of dihydrogen association
for the trihydride moiety. The spectra of Figure 5 indicate that
complex 9 has, as do compounds 3, 5, and 6, three chemically
inequivalent hydrido ligands, one of which does not couple with
the other two. Therefore, we assume that the structures of the
trihydrido-germyl derivatives 7-9 are the same as the struc-
tures of the trihydrido-silyl complexes 3, 5, and 6. In
agreement with this, the 31P{1H} spectra of 8 and 9 at room
temperature show singlets at 35.6 (8) and 27.7 (9) ppm, which
The behavior in solution of the three types of compounds
MH3(ER3)(CO)(PiPr3)2 (E ) Si, Ge, Sn) described is similar,
suggesting that all of them have the same arrangement of ligands
around of the osmium atom. However, the interactions of the
(27) Clark, G. R.; Flower, K. R.; Rickard, C. E. F.; Roper, W. R.; Salter,
D. M.; Wright, L. J.J. Organomet. Chem. 1993, 462, 331.

Oxidative Addition to OsH2(η2-CH2dCHEt)(CO)(PiPr3)2
Inorganic Chemistry, Vol. 35, No. 5, 1996 1255
(b) A suspension of OsH(η2-H2BH2)(CO)(PiPr3)2 (100 mg, 0.18
mmol) in 5 mL of methanol was treated with H2SiPh2 (70 µL, 0.36
mmol) and the mixture stirred for 1 h at room temperature. A white
solid was formed. The solvent was decanted and the solid washed
with methanol and dried in vacuo: yield 91.4 mg (70%). Anal. Calcd
for C31H56OOsP2Si: C, 51.36; H, 7.78. Found: C, 51.21; H, 8.29. IR
(Nujol, cm-1): ν(Si-H) 2075, ν(Os-H) 1995, ν(CO) 1890 (s). 1H
NMR (300 MHz, C6D6): δ 8.07 (d, 4H, JH-H ) 6.9 Hz, o-C6H5); 7.38
(dd, 4H, JH-H ) JH-H′ ) 9.1 Hz, m-C6H5); 7.15 (overlapped with the
signal of benzene-d6, p-C6H5); 6.52 (t, 1H, JP-H ) 12.1 Hz, Si-H);
2.21 (m, 6H, PCHCH3); 1.12 (dvt, 36H, N ) 14.1 Hz, JP-H ) 7.2 Hz,
PCHCH3); -9.65 (br, 3H, OsH3). 31P{1H} NMR (121.421 MHz,
C6D6): δ 37.3 (s).
silyl, germyl, or stannyl groups with one of the three hydrido
ligands of the complexes merits further consideration. In
solution, complexes 3 and 5-11 are fluxional, with the
chemically inequivalent hydrido ligands interchanging their
positions.28 Because the hydrido exchange must involve the
cleavage of the hydrido-silyl, -germyl, or -stannyl residual
interaction and the R3E-H bond energies decrease in the
sequence Si > Ge > Sn,29 one might expect a higher barrier of
activation for the fluxional process in the silyl and germyl
compounds than in the stannyl derivatives. In fact, the
enthalpies of activation for the silyl and germyl complexes 3
(10.6 ( 0.2 kcal mol-1) and 9 (11 ( 0.4 kcal mol-1) are higher
than the enthalpy estimated for the stannyl derivative 10 (about
6 kcal mol-1).
1H NMR (toluene-d8, 193 K) in the hydride region: δ -11.18 (t,
1H, JP-H ) 15.0 Hz); -9.11 (2H, AB part of a second order ABXY
spin system).
Preparation of OsH3(SiPh3)(CO)(PiPr3)2 (5). A suspension of
OsH(η2-H2BH2)(CO)(PiPr3)2 (120 mg, 0.22 mmol) in 5 mL of methanol
was treated with HSiPh3 (172 mg, 0.66 mmol). After the mixture was
stirred for 20 min at room temperature, a white solid precipitated. The
mixture was decanted and the resulting white solid repeatedly washed
with methanol and dried in vacuo: yield 140 mg (75%). Anal. Calcd
for C37H60OOsP2Si: C, 55.47; H, 7.55. Found: C, 55.53; H, 8.03. IR
(Nujol, cm-1): ν(Os-H) 2000, ν(CO) 1890. 1H NMR (300 MHz,
C6D6): δ 8.03 (d, 6H, JH-H ) 6.6 Hz, o-C6H5); 7.02 (m, 6H, m-C6H5);
7.27 (t, 3H, JH-H ) 7.1 Hz; p-C6H5); 1.88 (m, 6H, PCHCH3); 1.01
(dvt, 36H, N ) 12.9 Hz, JP-H ) 6.9 Hz, PCHCH3); -9.76 (br, 3H,
OsH3). 31P{1H} NMR (121.421 MHz, C6D6): δ 24.6 (s).
Concluding Remarks
This study has revealed that the dihydrido-olefin complex
OsH2(η2-CH2dCHEt)(CO)(PiPr3)2 reacts with R3E-H to give
the corresponding OsH3(ER3)(CO)(PiPr3)2 (E ) Si, Ge, Sn),
which can be formulated as derivatives of osmium (IV) with a
weak H-E agostic interaction.
For the three types of compound the arrangement of the
ligands around the osmium atom is the same. In the solid state
and in solution at very low temperatures the coordination
polyhedra can be described as a very distorted pentagonal
bipyramid with a hydrido ligand and the carbonyl group in the
axial positions. The other two hydrido ligands lie in the
equatorial plane, one between the phosphine ligands and the
other between the R3E group and one of the phosphine ligands.
In solution at room temperature all compounds are fluxional.
In conclusion, we report the synthesis and characterization
of the first trihydrido-silyl, trihydrido-germyl, and trihydrido-
stannyl derivatives of osmium(IV). The trihydrido-germyl
complexes also are the first examples of compounds of this type
for the iron triad.
1H NMR (toluene-d8, 193 K) in the hydride region: δ -9.92 (2H,
AB part of a second order ABXY spin system); -9.39 (t, 1H, JP-H
20.5 Hz).
)
Preparation of OsH3{Si(OCH3)2Ph}(CO)(PiPr3)2 (6). A suspen-
sion of OsH(η2-H2BH2)(CO)(PiPr3)2 (120 mg, 0.22 mmol) in 4 mL of
methanol was treated with H3SiPh (166 mg, 0.3 mmol) and the mixture
stirred for 1 h at room temperature. The solution was stored at -78
°C for 24 h . A white solid was formed. The mixture was decanted
and the resulting white solid was washed with methanol and dried in
vacuo: yield 137 mg (65%). Anal. Calcd for C27H56O3OsP2Si: C,
45.7; H, 7.96. Found: C, 45.86; H, 9.06. IR (Nujol, cm-1): ν(Os-
H) 2000, ν(CO) 1900, ν(Si-O) 1075 (s). 1H NMR (300 MHz, C6D6):
δ 8.05 (d, 2H, JH-H ) 6.6 Hz, o-C6H5); 7.35 (dd, 2H, JH-H ) 6.6 Hz,
JH-H′ ) 7.5 Hz, m-C6H5); 7.19 (t, 1H, JH-H ) 7.5 Hz, p-C6H5); 3.66
(s, 6H, Si-OCH3); 1.99 (m, 6H, PCHCH3); 1.08 (dvt, 36H, N ) 13.1
Hz, JP-H ) 7.1 Hz, PCHCH3); -10.89 (t, 3H, JP-H ) 8.8 Hz, OsH3).
31P{1H} NMR (121.421 MHz, C6D6): δ 30.0 (s).
Experimental Section
General Considerations. All reactions were carried out under an
argon atmosphere by using Schlenk techniques. Solvents were dried
and purified by known procedures and distilled under argon prior to
use. The starting complexes OsH2(η2-CH2dCHEt)(CO)(PiPr3)2 (2)7 and
OsH(η2-H2BH2)(CO)(PiPr3)2 (4)30 were prepared by a published method.
Physical Measurements. NMR spectra were recorded on a Varian
UNITY 300 or on a Bruker AXR 300 spectrometer at room temperature
unless stated. Chemical shifts are expresed in parts per million, upfield
from Si(CH3)4 (1H) and 85% H3PO4 (31P{1H} NMR spectra). Coupling
constants J and N (N ) J(HP) + J(HP′)) are given in Hertz. The T1
experiments were performed on a Varian UNITY 300 spectrometer
with a standard 180°-τ-90° pulse sequence. T1 values are given in
milliseconds (ms). Infrared spectra were recorded on a Perkin-Elmer
783 spectrometer using Nujol mulls on polyethylene sheets. C and H
analyses were carried out on a Perkin-Elmer 240C microanalyzer.
Preparation of OsH3(SiHPh2)(CO)(PiPr3)2 (3). The complex can
be prepared by using two different procedures.
(a) A solution of OsH2(η2-CH2dCHEt)(CO)(PiPr3)2 (ca. 200 mg,
0.35 mmol) in 5 mL of hexane was treated with H2SiPh2 (135.6 µL,
0.70 mmol). The mixture was stirred for 1 h at room temperature and
concentrated in vacuo to dryness. Addition of methanol to the resulting
residue gave a white solid. The mixture was decanted and the resulting
white solid was washed with methanol and dried in vacuo: yield 190.3
mg (75%).
1H NMR (toluene-d8, 193 K) in the hydride region: δ -10.95 (2H,
AB part of a second order ABXY spin system); -10.04 (t, 1H, JP-H
20.0 Hz).
)
Preparation of OsH3(GeHPh2)(CO)(PiPr3)2 (7). A solution of
OsH2(η2-CH2dCHEt)(CO)(PiPr3)2 (ca. 200 mg, 0.35 mmol) in 5 mL
of hexane was treated with H2GePh2 (159.6 µL, 0.70 mmol). The
mixture was stirred for 6 h at room temperature and concentrated in
vacuo to dryness, leaving a yellow oil. 1H NMR (300 MHz, C6D6):
δ 8.02 (dd, 4H, JH-H ) 6.6 Hz, JH-H′ ) 1.0 Hz, o-C6H5); 7.31 (t, 4H,
JH-H ) 6.6 Hz, JH-H′ ) 7.2 Hz, m-C6H5); 7.18 (m, 2H, p-C6H5); 5.89
(t, 1H, JP-H ) 11.5 Hz, Ge-H); 2.19 (m, 6H, PCHCH3); 1.04 (dvt,
36H, N ) 14.1 Hz, JP-H ) 7.1 Hz, PCHCH3); -9.72 (t, 3H, JP-H
)
14.9 Hz, OsH3). 31P{1H} NMR (121.421 MHz, C6D6): δ 38.9 (s).
1H NMR (toluene-d8, 193 K) in the hydride region: δ -9.72 (br,
3H).
Preparation of OsH3(GePh3)(CO)(PiPr3)2 (8). A solution of
OsH2(η2-CH2dCHEt)(CO)(PiPr3)2 (ca. 150 mg, 0.261 mmol) in 5 mL
of hexane was treated with HGePh3 (159 mg, 0.522 mmol). The
mixture was stirred for 6 h at room temperature, and a white solid was
formed. The solvent was decanted and the solid washed with hexane
and dried in vacuo: yield 137 mg (62%). Anal. Calcd for C37H60-
GeOOsP2: C, 52.55; H, 7.15. Found: C, 53.05; H, 7.40. IR (Nujol,
cm-1): ν(Os-H) 1966, ν(CO) 1867. 1H NMR (300 MHz, C7D8): δ
8.03 (d, 6H, JH-H ) 7.5 Hz, o-C6H5); 7.56 (m, 6H, m-C6H5); 7.23 (t,
3H, JH-H ) 6.9 Hz, p-C6H5); 1.94 (m, 6H, PCHCH3); 0.96 (dvt, 36H,
N ) 12.3 Hz, JP-H ) 7.2 Hz, PCHCH3); -9.63 (t, 3H, JP-H ) 15 Hz,
OsH3). 31P{1H} NMR (121.421 MHz, C6D6): δ 35.6 (s).
(28) Because the chemical shift of the triplets is more dependent upon the
nature of the ER3 groups than the chemical shift of the ABXY systems,
we assign the triplets to the corresponding H(3) hydrido ligands.
(29) (a) Jackson, R. A. J. Organomet. Chem. 1979, 166, 17. (b) Woo, H.
G.; Freeman, W. P.; Tilley, T. D. Organometallics 1992, 11, 2198.
(30) Werner, H.; Esteruelas, M. A.; Meyer, U.; Wrackmeyer, B. Chem.
Ber. 1987, 120, 11.

1256 Inorganic Chemistry, Vol. 35, No. 5, 1996
Buil et al.
Table 3. Crystal Data and Data Refinement for
OsH3(CO)(SiHPh2)(PiPr3)2 (3)
reflections were corrected for Lorentz and polarization effects. Three
orientation and intensity standards were monitored every 55 min of
measuring time; no variation was observed. Reflections were also
corrected for absorption by an empirical method.31
formula: C31H56OP2SiOs
a ) 16.375(2) Å
b ) 11.670(1) Å
c ) 18.806(2) Å
â ) 107.67(1)°
temp ) 20 °C
λ ) 0.710 73 Å
F (calcd) ) 1.406 g cm-1
µ ) 3.87 mm-1
Ra ) 0.0452
The structure was solved by Patterson (Os atom) and conventional
Fourier techniques. Refinement was carried out by full-matrix least-
squares methods with initial isotropic thermal parameters. Anisotropic
thermal parameters were used in the last cycles of refinement for all
non-hydrogen atoms. Hydride ligands were not located or refined
appropriately. Hydrogen atoms were observed or calculated (C-H )
0.97 Å), and included in the refinement riding on carbon atoms with a
common isotropic thermal parameter. Atomic scattering factors,
corrected for anomalous dispersion for Os and P, were taken from ref
32. Final R and Rw values were 0.0452 and 0.0489. All calculations
were performed by use of the SHELXTL-PLUS system of computer
programs.33
Z ) 4
Rwb ) 0.0489
fw ) 725.02
space group: P21/c (No. 14)
Sc ) 1.603
a R ) ∑|[Fo - Fc]|/∑Fo. b Rw ) ∑(w1/2|[Fo - Fc]|)/(∑w1/2Fo). c S )
2
{∑(w|[Fo - Fc]| )/(M - N)}1/2, where M is the number of observed
reflections and N is the number of data.
1H NMR (toluene-d8, 193 K) in the hydride region: δ -9.63 (br,
3H).
Preparation of OsH3(GeEt3)(CO)(PiPr3)2 (9). A solution of
OsH2(η2-CH2dCHEt)(CO)(PiPr3)2 (ca. 150 mg, 0.261 mmol) in 5 mL
of hexane was treated with HGeEt3 (126 µL, 0.783 mmol). The mixture
was stirred for 1 h at room temperature and concentrated in vacuo to
dryness. Addition of methanol to the resulting residue gave a solid.
The mixture was decanted and the resulting orange solid washed with
methanol and dried in vacuo: yield 109.8 mg (60%). Anal. Calcd
for C25H60GeOOsP2: C, 42.8; H, 8.62. Found: C, 42.93; H, 8.56 IR
(Nujol, cm-1): ν(Os-H) 1957, ν(CO) 1870. 1H NMR (300 MHz,
C6D6): δ 2.01 (m, 6H, PCHCH3); 1.15 (dvt, 36H, N ) 13.8 Hz, JP-H
) 6.9 Hz, PCHCH3); 0.99 (t, 9H, JH-H ) 7.5 Hz, CH3); 0.72 (q, 6H,
JH-H ) 8 Hz, CH2); -10.41 (br, 3H, OsH3). 31P{1H} NMR (121.421
MHz, C6D6): δ 27.7 (s).
Computational Details. All calculations were performed with the
GAUSSIAN 92 program.34 A molecular orbital ab initio method with
introduction of correlation energy through the second level of the
Møeller-Plesset (MP2) perturbational approach was applied.35 Excita-
tions concerning the lowest energy electrons were excluded in the MP2
calculations (frozen core approach). Effective core potentials (ECP)
were used to represent the 60 innermost electrons (up to the 4d shell)
of the osmium atom,36 as well as the 10-electron core of the phosphorus
and silicon atoms.37 The basis set used for the osmium atom was that
associated to the pseudopotential,35 with the valence double-ú (341/
321/21) contraction included in the program (LANL2DZ basis set).34
For the phosphorus and silicon atoms, a valence double-ú basis set36
with a (21/21) contraction was used, supplemented with a polarization
d shell for each atom.38 The hydrogen atoms directly attached to the
metal were described also with a valence double-ú basis set supple-
mented with a polarization shell (6-31G**).39 Finally, the remaining
atoms, carbon, oxygen, and the hydrogen atoms attached to the
phosphorus and silicon atoms, were described with the 6-31G basis
set.40
1H NMR (toluene-d8, 193 K) in the hydride region: δ -11.20 (t,
1H, JP-H ) 21 Hz); -9.90 (t, 1H, AB part of a second order ABXY
spin system).
Preparation of OsH3(SnPh3)(CO)(PiPr3)2 (10). A solution of
OsH2(η2-CH2dCHEt)(CO)(PiPr3)2 (ca. 200 mg, 0.35 mmol) in 5 mL
of hexane was treated with HSnPh3 (244.1 mg, 0.70 mmol). The
mixture was stirred for half an hour at room temperature and
concentrated in vacuo to dryness. Addition of methanol to the resulting
residue gave a solid. The mixture was decanted, and the resulting white
solid was washed with methanol and dried in vacuo: yield 233.6 mg
(75%). Anal. Calcd for C37H60OOsP2Sn: C, 49.84 H, 6.78. Found:
C, 50.07; H, 6.70. IR (Nujol, cm-1): ν(Os-H) 2080, ν(CO) 1966,
ν(Sn-C) 247. 1H NMR (300 MHz, C6D6): δ 8.11 (d, 6H, JH-H ) 6.6
Acknowledgment. We thank the DGICYT (Projects PB92-
0092, PB92-0621, and PB93-0222, Programa de Promocio´n
General del Conocimiento) and the EU (Project: Selective
Processes and Catalysis involving Small Molecules) for financial
support. E.O. thanks the DGA (Diputacio´n General de Arago´n)
for a grant.
117
119
Hz, J Sn-H ) 32.9 Hz, J Sn-H ) 47 Hz, o-C6H5); 7.32 (dd, 6H, JH-H
) 6.6 Hz, JH-H′ ) 7.1 Hz, m-C6H5); 7.19 (t, 3H, JH-H ) 7.1 Hz,
Supporting Information Available: Tables of atomic coordinates
and equivalent isotropic displacement coefficients, anisotropic thermal
parameters, experimental details of the X-ray study, bond distances
and angles, and interatomic distances (12 pages). Ordering information
is given on any current masthead page.
p-C6H5); 2.05 (m, 6H, PCHCH3); 1.03 (dvt, 36H, N ) 14.0 Hz, JP-H
) 6.9 Hz, PCHCH3); -9.90 (t, 3H, JP-H ) 15.1 Hz, J
117/119
Sn-H ) 52.2
31
1
117/
Hz, OsH3). P{ H} NMR (121.421 MHz, C6D6): δ 39.3 ((s), J
) 69.5 Hz).
119
Sn-P
1H NMR (toluene-d8, 193 K) in the hydride region: δ -10.0 (br,
IC9509591
1H); -10.99 (br, 2H).
Preparation of OsH3(SnnBu3)(CO)(PiPr3)2 (11). A solution of
OsH2(η2-CH2dCHEt)(CO)(PiPr3)2 (ca. 200 mg, 0.35 mmol) in 5 mL
of hexane was treated with HSnnBu3 (118 µL, 0.70 mmol). The mixture
was stirred for 1 h at room temperature and concentrated in vacuo to
dryness, leaving an orange oil. 1H NMR (300 MHz, C6D6): δ 2.1-
(31) Walker, N.; Stuart, D. Acta Crystallogr. 1983, A39, 158.
(32) International Tables for X-Ray Crystallography; Kynoch Press:
Birmingham, England, 1974; Vol. IV.
(33) Sheldrick, G. M. SHELXTL-PLUS; Siemens Analytical X-ray Instru-
ments Inc.: Madison, WI, 1990.
(34) Frisch, M. J.; Trucks, G. W.; Head-Gordon, M.; Gill, P. M. W.; Wong,
M. W.; Foresman, J. B.; Johnson, B. G.; Schlegel, H. B.; Robb, M.
A.; Replogle, E. S.; Gomperts, R.; Andre´s, J. L.; Raghavachari, K.;
Binkley, J. S.; Gonza´lez, C.; Mart´ın, R. L.; Fox, D. J.; DeFrees, D. J.;
Baker, J.; Steward, J. J. P.; Pople, J. A. GAUSSIAN 92. Gaussian
Inc., Pittsburgh, PA, 1992.
1.0 (the signals for PiPr3 and SnnBu3 are buried under resonance for
HSnnBu3 and hexane); -10.72 (t, 3H, JP-H ) 13.5 Hz, J
)
117/
117/119
Sn-H
31
1
68.1 Hz, OsH3). P{ H} NMR (121.421 MHz, C6D6): δ 34.0 (s, J
) 33.4 Hz).
119
Sn-P
X-ray Structure Analysis of OsH3(CO)(SiHPh2)(PiPr3)2 (3).
Crystals suitable for a single-crystal X-ray analysis were obtained for
a concentrated solution of 3 in methanol at -18 °C. A summary of
crystal data, intensity collection procedures, and refinement data is
reported in Table 3. The prismatic crystal studied was glued on a glass
fiber and mounted on a Siemens-Stoe AED-2 diffractometer. Cell
constants were obtained from the least-squares fit of the setting angles
of 62 reflections in the range 20 e 2θ e 40°. The 7953 recorded
(35) Møeller, C.; Plesset, M. S. Phys. ReV. 1934, 46, 618.
(36) Hay, P. J.; Wadt, W. R. J. Chem. Phys. 1985, 82, 299.
(37) Hay, P. J.; Wadt, W. R. J. Chem. Phys. 1985, 82, 284.
(38) Francl, M. M.; Pietro, W. J.; Hehre, W. J.; Binkley, J. S.; Gordon, M.
S.; DeFrees, D. J.; Pople, J. A. J. Chem. Phys. 1982, 77, 3654.
(39) Hariharan, P. C.; Pople, J. A. Theor. Chim. Acta 1973, 28, 213.
(40) Hehre, W. J.; Ditchfield, R.; Pople, J. A. J. Chem. Phys. 1972, 56,
2257.