H?H interaction in four-membered P-H?H-M (M = osmium, ruthenium) rings

Article abstract of DOI:10.1021/om9803218

The dihydrido-1-butene complex OsH₂(η²-CH₂=CHEt)(CO)(PⁱPr ₃)₂ (1) reacts with PHPh₂ to give OsH₂(CO)(PHPh₂)(PⁱPr₃)₂ (2), wh

Full text of DOI:10.1021/om9803218

3346
Organometallics 1998, 17, 3346-3355
H‚‚‚H In ter a ction in F ou r -Mem ber ed P -H‚‚‚H-M (M )
Osm iu m , Ru th en iu m ) Rin gs
Mar´ıa L. Buil, Miguel A. Esteruelas,* Enrique On˜ate, and Natividad Ruiz
Departamento de Quı´mica Inorga´nica, Instituto de Ciencia de Materiales de Arago´n,
Universidad de Zaragoza, CSIC, 50009 Zaragoza, Spain
Received April 27, 1998
The dihydrido-1-butene complex OsH2(η2-CH2dCHEt)(CO)(PiPr3)2 (1) reacts with PHPh2
to give OsH2(CO)(PHPh2)(PiPr3)2 (2), which can also be prepared from the reaction of OsH-
(η2-H2BH2)(CO)(PiPr3)2 (3) with PHPh2. Similarly, treatment of RuH(η2-H2BH2)(CO)(PiPr3)2
(4) with PHPh2 affords RuH2(CO)(PHPh2)(PiPr3)2 (5). Complex 2 reacts with HBF4 in
dichloromethane-d2 as the solvent to give the cis-hydrido-dihydrogen derivative [OsH(η2-
H2)(CO)(PHPh2)(PiPr3)2]BF4 (6), which in solution exchanges the relative positions of the
hydrido and dihydrogen ligands. The protonation of 2 with HBF4 in acetone affords the
solvate complex [OsH{η1-OC(CH3)2}(CO)(PHPh2)(PiPr3)2]BF4 (7). The reaction of 7 with
carbon monoxide leads to a mixture of the cis-dicarbonyl-[OsH(CO)2(PHPh2)(PiPr3)2]BF4 (8)
and trans-dicarbonyl-[OsH(CO)2(PHPh2)(PiPr3)2]BF4 (9). The reactions of 7 with CH3CN,
LiCtCPh, and KBr give [OsH(CH3CN)(CO)(PHPh2)(PiPr3)2]BF4 (10), OsH(C2Ph)(CO)
(PHPh2)(PiPr3)2 (11), and OsHBr(CO)(PHPh2)(PiPr3)2 (12), respectively. The structures of 5
and 8 have been determined by X-ray diffraction analysis. In both cases, the coordination
geometry around the metal center is octahedral, with the two triisopropylphosphine ligands
in a trans position. Also in both cases, the H-P hydrogen atom of the diphenylphosphine
ligand points toward one hydrido ligand, suggesting that there is a H‚‚‚H interaction between
the hydrido and the HP hydrogen atom. For 5 the H-H separation is about 2.6 Å, while for
8 the H-H separation is about 2.9 Å. Spectroscopic studies also suggest that one of the
hydrido ligands of 2 and the HP hydrogen atom of the diphenylphosphine interact. In this
case, the estimated H-H separation is 2.5 Å. In 2 and 5, the H‚‚‚H interaction blocks the
free rotation of the diphenylphosphine group around the Os-P axis, while in 8 it only permits
a light oscillation.
In tr od u ction
the sulfur analogue the S-H group is pointing away
from the hydrido. Furthermore, the Ir-O-H angle
(104.4(7)°) is significantly smaller than the normal
tetrahedral value, as opposed to 111(3)° in [IrH(SH)-
(PMe3)4]PF6 or 119.4(9)° in the analogous compound cis-
[IrH(OMe)(PMe3)4]PF6.3
These observations have been rationalized by postu-
lating an attractive interaction between the hydridic
Ir-H and the OH proton, although spectroscopic evidences
in favor of such an interaction have not been found.2,3
Hydrogen bonding is a phenomenon of wide signifi-
cance; hydrogen bonding takes place between an electron-
deficient hydrogen and a region of high electron den-
sity.1
In 1986, Milstein et al. observed that the iridium
complex [Ir(PMe3)4]PF6 reacted with H2O and H2S to
afford the cis-hydrido-hydroxo compound [IrH(OH)-
(PMe3)4]PF6 and the related cis-hydrido-mercapto de-
rivative [IrH(SH)(PMe3)4]PF6.2 A comparison of the
structure of the hydrido-hydroxo complex with that of
the hydrido-mercapto compound shows that one of the
O-H group points toward the hydrido ligand while in
As a result of the interaction, the O-H‚‚‚H-Ir unit
forms a four-membered ring with a hydrogen-hydrogen
separation of 2.40(1) Å.3
Recently, some examples of hydridoiridium complexes
containing related intramolecular hydrogen-hydrogen
interactions have been reported, where the unit involved
in the interactions forms six-membered rings. As a
consequence of this more favored geometry, the interac-
tions are stronger than that in [IrH(OH)(PMe3)4]PF6
and they can be indirectly detected by spectroscopic
methods. In these cases, the estimated hydrogen-
hydrogen separations are in the range 1.6-1.8 Å.4
(1) (a) Pimentel, G. C.; McClellan, A. L. The Hydrogen Bond;
Freeman: San Francisco, CA, 1960. (b) Hamilton, W. C.; Ibers, J . A.
Hydrogen Bonding in Solids; Benjamin: New York, 1968. (c) Pimentel,
G. C.; McClellan, A. L. Annu. Rev. Phys. Chem. 1971, 22, 347. (d)
Kollman, P. A.; Allen, L. C. Chem. Rev. 1972, 72, 283. (e) J effrey, G.
A.; Saenger, W. Hydrogen Bonding in Biological Structures; Springer:
Berlin, 1991. (f) Yap, G. P. A.; Rheingold, A. L.; Das, P.; Crabtree, R.
H. Inorg. Chem. 1995, 34, 3474. (g) Wessel, J .; Lee, J . C.; Peris, E.;
Yap, G. P. A.; Fortin, J . B.; Ricci, J . S.; Sini, G.; Albinati, A.; Koetzle,
T. F.; Einsenstein, O.; Rheingold, A. L.; Crabtree, R. H. Angew. Chem.,
Int. Ed. Engl. 1995, 34, 2507. (h) Patel, B. P.; Yao, W.; Yap, G. P. A.;
Rheingold, A. L.; Crabtree, R. H. J . Chem. Soc., Chem. Commun. 1996,
991.
(2) Milstein, D.; Calabrese, J . C.; Williams, I. D. J . Am. Chem. Soc.
1986, 108, 6387.
(3) Stevens, R. C.; Bau, R.; Mistein, D.; Blum, O.; Koetzle, T. F. J .
Chem. Soc., Dalton Trans. 1990, 1429.
S0276-7333(98)00321-5 CCC: $15.00 © 1998 American Chemical Society
Publication on Web 06/30/1998

Four-Membered P-H‚‚‚H-M (M ) Os, Ru) Rings
Organometallics, Vol. 17, No. 15, 1998 3347
The force of an electrostatic interaction as postulated
in the above-mentioned cases is proportional to the
charges of the particles involved and inversily propor-
tional to the separations between them. So, the weak-
ness of the hydrogen-hydrogen interaction in [IrH(OH)-
(PMe3)4]PF6 is not only a consequence of the long hydro-
gen-hydrogen separation, but also of the low charges
supported by the hydrogen atoms. For a four membered
ring of the type L-H‚‚‚H-M, the separation between
the hydrogen atoms must be necessarily long. However,
one can modify the charges on them by increasing both
the nucleophilic character of the hydrido ligand and the
electrophilic character of the H-L hydrogen atom.
At first glance, the hydrido ligand of a neutral
transition-metal hydrido compound should be more
nucleophilic than that of a cationic one. This prompted
us to prepare the complexes MH2(CO)(PHPh2)(PiPr3)2
(M ) Os, Ru) and to investigate the influence of the
interaction between one of the hydrido ligands and the
PH hydrogen atom on the structure and dynamic
properties of the compounds. In this paper, we report
the results from this study.
F igu r e 1. Molecular diagram of RuH2(CO)(PHPh2)(PiPr3)2
(5).
Ta ble 1. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for Ru H2(CO)(P HP h 2)(P iP r 3)2 (5)
Ru-P(1)
Ru-P(2)
Ru-P(3)
Ru-C(1)
Ru-H(01)
Ru-H(02)
2.3264(8)
2.3504(8)
2.3496(8)
1.896(3)
1.66(3)
C(1)-O
1.158(4)
1.843(3)
1.847(3)
1.34(3)
P(1)-C(2)
P(1)-C(8)
P(1)-H(03)
H(02)-H(03)
2.63(5)
1.63(4)
Resu lts a n d Discu ssion
P(1)-Ru-P(2)
P(1)-Ru-C(1)
100.74(3)
97.39(10) H(01)-Ru-H(02)
P(1)-Ru-H(01) 166.2(10)
C(1)-Ru-P(3)
97.10(10)
85.9(16)
79.1(10)
H‚‚‚H In ter a ction in MH2(CO)(P HP h 2)(P iP r 3)2 (M
) Os, Ru ). The addition of 1 equiv of diphenylphos-
phine to a hexane solution of the dihydrido-1-butene
complex OsH2(η2-CH2dCHEt)(CO)(PiPr3)2 (1) produces
the displacement of the coordinated olefin and the
formation of OsH2(CO)(PHPh2)(PiPr3)2 (2), which was
isolated as a white solid in 62% yield, eq 1.
H(01)-Ru-P(3)
H(02)-Ru-P(3)
Ru-P(1)-C(2)
P(1)-Ru-H(02)
P(1)-Ru-P(3)
P(2)-Ru-C(1)
P(2)-Ru-H(01)
P(2)-Ru-H(02)
P(2)-Ru-P(3)
C(1)-Ru-H(01)
80.4(12)
100.68(3)
97.51(10) Ru-P(1)-H(03)
75.9(10)
84.1(12)
152.20(3)
96.3(11)
82.2(12)
120.19(10)
114.1(13)
123.94(9)
97.5(14)
97.63(13)
98.3(13)
Ru-P(1)-C(8)
C(2)-P(1)-H(03)
C(2)-P(1)-C(8)
H(03)-P(1)-C(8)
C(1)-Ru-H(02) 177.5(12)
Figure 1 shows a view of the molecular geometry of
5. Selected bond distances and angles are listed in
Table 1. The hydrido ligands (H(01) and H(02)) and the
hydrogen atom H(03) were located in the difference
Fourier maps and refined as isotropic atoms together
with the rest of the non-hydrogen atoms of the structure,
giving Ru-H(01), Ru-H(02), and P(1)-H(03) distances
of 1.66(3), 1.63(4) and 1.34(3) Å, respectively.
Complex 2 can be also prepared in 67% yield by
reaction of the octahedral tetrahydrido borato compound
OsH(η2-H2BH2)(CO)(PiPr3)2 (3) with diphenylphosphine.
Similarly, the treatment of RuH(η2-H2BH2)(CO)(PiPr3)2
(4) with this phosphine in methanol affords the related
ruthenium derivative RuH2(CO)(PHPh2)(PiPr3)2 (5),
which was isolated as a white solid in 68% yield, eq 2.
The ruthenium atom is coordinated in a somewhat
octahedral fashion with the two triisopropylphosphine
ligands in a pseudo-trans position (P(2)-Ru-P(3))
152.20(3)°). The perpendicular plane is formed by the
hydrido ligands H(01) and H(02), the carbonyl group
trans disposed to H(02) (C(1)-Ru-H(02)) 177.5(12)°),
and the diphenylphosphine trans disposed to H(01)
(P(1)-Ru-H(01)) 166.2(10)°).
Without doubt, the most noticeable feature of the
structure is the coplanarity of the group of atoms C(1),
O, H(01), Ru, H(02), P(1), and H(03). The deviations
from the best plane are -0.006(4) (C(1)), 0.002(3) (O),
-0.042(32) (H(01)), 0.000(1) (Ru), 0.038(38) (H(02)),
0.000(1) (P(1)), and -0.004(34) (H(03)) and the value of
the torsion angle H(02)-Ru-P(1)-H(03) is -2(2)°. This
strongly supports the formation of a four-membered
(4) (a) Lee, J . C.; Rheingold, A. L.; Muller, B.; Pregosin, P. S.;
Crabtree, R. H. J . Chem. Soc., Chem. Commun. 1994, 1021. (b) Lough,
A. J .; Park, S.; Ramachandran, R.; Morris, R. H. J . Am. Chem. Soc.
1994, 116, 8356. (c) Park, S.; Ramachandran, R.; Lough, A. J .; Morris,
R. H. J . Chem. Soc., Chem. Commun. 1994, 2201. (d) Lee, J . C.; Peris,
E.; Rheingold, A. L.; Crabtree, R. H. J . Am. Chem. Soc. 1994, 116,
11014.
P(1)-H(03)‚‚‚H(02)-Ru ring stabilized by electrostatic
interaction between H(03) and H(02). The H(02)-H(03)
separation is 2.63(5) Å.
This interaction also appears to have a significant
influence on the coordination of the diphenylphosphine.

3348 Organometallics, Vol. 17, No. 15, 1998
Buil et al.
nances of the spectrum shown in Figure 3a split into a
double doublet (H(03)), doublet of doublets of doublets
(H(02)), and double doublet (H(01)) with H-P(1) cou-
pling constants of 315.5 (H(03)), 28.2 (H(02)), and 77.9
Hz (H(01)). Coupling between H(01) and H(03) is not
observed.
In this context, it should be mentioned that the
complexes (CO)5W(µ-PPh2)OsH(CO)2(PHPh2)(PMePh2)
and (CO)5W(µ-PPh2)OsH(CO)(PHPh2)(PMePh2) contain-
ing a diphenylphosphine cis-disposed to the hydrido
ligand have been previously reported.7 While in the
first of them the hydrido ligand is coupled with the HP
hydrogen (J H-H ) 3.6 Hz), in the second one this
coupling is not observed. Coupling between the HP
hydrogen and the hydrido ligands in the complexes
(η5-C5H5)NiOs3(µ-H)3(CO)8(PHPh2) and (η5-C5H5)NiOs3-
(µ-H)2(µ-HgBr)(CO)8(PHPh2) is not observed either.8
At first glance, the chemical equivalence of the
triisopropylphosphine ligands in the 31P{1H} NMR
spectrum could be also explained in terms of an almost
free rotation of the diphenylphosphine moiety with a
time average Cs symmetry. However, it should be noted
that in the 1H NMR spectrum, neither the chemical
shifts of H(02) and H(03) nor the H(02)-H(03) coupling
constants can be identical in rotamers a , b, and c
(Figure 4) and that rotamer a (the only one present, at
least, in the solid state) is more stable than the others.
If the three rotamers have different energies, in solu-
tion, the position of a possible equilibrium between
them, as a result from the rotation of the diphenylphos-
phine group around the Ru-PH axis, should be deter-
mined by the energy difference between the rotamers.
Thus, the observed chemical shifts of H(02) and H(03)
and the H(02)-H(03) coupling constant should be a
function of the molar fraction of each rotamer according
to eqs 3 and 4.9 Then, if the spectrum is recorded at
F igu r e 2. 1H COSY NMR of the complex RuH2(CO)-
(PHPh2)(PiPr3)2 (5).
Although the hydrido ligands show a great trans-influ-
ence and P(1) is trans disposed to H(01), the Ru-P(1)
bond length (2.3264(8) Å) is about 0.03 Å shorter than
the Ru-triisopropylphosphine distances (2.3504(8) and
2.3496(8) Å). The Ru-P(1) bond length is also between
0.03 and 0.04 Å shorter than the Ru-P distances found
in RuCl2(PHPh2)4 (2.3505(8) and 2.3665(8) Å).5 The
approach of the diphenylphosphine to the ruthenium
atom produces a large steric hindrance between the
isopropyl and phenyl groups of the phosphines. As a
result, the P(2)-Ru-P(3) axis undergoes a folding
toward the hydrido ligands and the C(2)-P(1)-C(8)
angle (97.63(13)°) closes up slightly.6
δ ) x1δa + x2δb + x3δc
J ) x1J a + x2J b + x3J c
(3)
(4)
1
The 31P{1H} and H NMR spectra of 5 are tempera-
ture invariant between 363 and 183 K. In agreement
with the disposition of the phenyl groups in Figure 1,
the triisopropylphosphine ligands are chemically equiva-
lent and, as a consequence, the 31P{1H} NMR spectrum
shows a doublet at 74.9 ppm for these ligands and a
triplet at 20.2 ppm for the diphenylphosphine. The P-P
different temperatures, the equilibrium ratios are shifted.
In such a case, one should expect changes in the
spectrum, and this is not observed for our complex. So,
the independence of the 1H NMR spectrum with the
temperature suggests that the rotation of the diphen-
ylphosphine group around the Ru-PH bond is blocked,
as a result of a strong H(02)‚‚‚H(03) interaction.
The T1 values for the resonances corresponding to
H(01) and H(02) were determined over the temperature
range of 293-193 K. The T1(min) values for the two
resonances were found to the same temperature, 233
K. The lower T1(min) value at 300 MHz for H(02) (231
ms) versus H(01) (251 ms) implies an excess relaxation
rate for H(02) of 0.35 s-1. Using the standard equation10
and assuming, according to a blocked rotation of the
PHPh2 group, that the H(02)-H(03) vector rotates with
the molecule as a whole, the H(02)‚‚‚H(03) separation
1
coupling constant is 19.3 Hz. In the H NMR spectrum,
the most noticeable feature is the coupling between the
resonances assigned to H(02) and H(03), as supported
1
by the H-COSY and selective heteronuclear 1H{31P}
NMR spectra shown in Figures 2 and 3. In the 1H{31P}
NMR spectrum (Figure 3a), the resonance due to H(03)
appears at 6.88 ppm as a doublet with a H(03)-H(02)
coupling constant of 4.1 Hz while that corresponding
to H(02) is observed at -8.51 ppm as a double doublet
with a H(02)-H(01) coupling constant of 6.1 Hz. The
H(01) ligand gives rise to a doublet at -9.58 ppm. With
PiPr3 coupling (Figure 3b), these resonances split into
a triplet of doublets, triplet of doublets of doublets, and
triplet of doublets, respectively, with H-P coupling
constants of 7.8 (H(03)), 16.8 (H(02)), and 25.7 Hz
(H(01)). With PHPh2 coupling (Figure 3c), the reso-
(7) (a) Rosenberg, S.; Whittle, R. R.; Geoffroy, G. L. J . Am. Chem.
Soc. 1984, 106, 5934. (b) Rosenberg, S.; Geoffroy, G. L.; Rheingold, A.
L. Organometallics 1985, 4, 1184.
(8) Predieri, G.; Tiripicchio, A.; Vignali, C.; Sappa, E.; Braunstein,
P. J . Chem. Soc., Dalton Trans. 1986, 1135.
(9) Friebolin, H. Basic One-and Two-Dimensional NMR Spectros-
copy; VCH Verlagsgesellschaft: Weinheim, 1991.
(10) R ) 129.18/r6. See ref 11.
(5) McAslan, E. B.; Blake, A. J .; Stephenson, T. A. Acta Crystallogr.
1989, C45, 1811.
(6) The related angles in RuCl2(PHPh2)4 are 100.18(12)° and 101.30-
(11)°. See ref 5.

Four-Membered P-H‚‚‚H-M (M ) Os, Ru) Rings
Organometallics, Vol. 17, No. 15, 1998 3349
1
1
1
F igu r e 3. 1H NMR spectra of RuH2(CO)(PHPh2)(PiPr3)2 (5) in benzene-d6: (a) H{31P}; (b) H{PHPh2}; (c) H{PiPr3}.
phine appears at -9.94 ppm as a triplet of doublets of
doublets of doublets with H-P coupling constants of
21.7 (PiPr3) and 21.4 (PHPh2) Hz.
The T1 values for the HP and hydrido resonances were
determined over the temperature range 293-213 K. As
for 2, T1(min) values for the three resonances were
found at 233 K. At 300 MHz, the T1(min) value of the
HP resonance is 188 ms while those of hydrido reso-
nances are 227 (hydrido cis to PHPh2) and 258 ms
(hydrido trans to PHPh2). From these values, an excess
relaxation rate for the hydrido cis to HPPh2 of 0.53 s-1
can be calculated, which leads to an estimated H‚‚‚H
separation of 2.50 Å.10,11
The nucleophilic character of analogous hydrido com-
plexes usually increases down a column in the periodic
Figu r e 4. Possible rotamers of complex RuH2(CO)(PHPh2)-
table.12 In this sense, it should be noted that the
calculated H‚‚‚H separation in 2 is about 0.2 Å shorter
than that calculated for 5, which appears to corroborate
the electrostatic character of these interactions.
(PiPr3)2 (5).
can be estimated to be about 2.68 Å, which agrees very
well with that determined by X-ray diffraction (2.63(5)
Å).
H‚‚‚H In ter a ction in [OsHL(CO)(P HP h 2)(P iP r 3)2]-
BF 4 (L ) H2, CO). Although the net positive charge
on the complex should increase the acidity of the P-H
group, it is also true that a cationic charge and the
substitution of σ-donor for π-acceptor groups should
decrease the nucleophilicity of the hydrido ligands.13 The
latter prompted us to prepare new cationic hydrido-
The 31P{1H} and 1H NMR spectra of OsH2(CO)-
(PHPh2)(PiPr3)2 (2) are similar to those of 5. The
31P{1H} spectrum consists of a doublet at 35.1 ppm and
a triplet at -18.6 ppm (J P-P ) 13.9 Hz), in agreement
with a diphenylphosphine cis-disposed to two equivalent
triisopropylphosphine ligands. In the 1H NMR spec-
trum, the resonance of the HP hydrogen atom appears
at 7.44 ppm as a doublet of triplets of doublets, with a
H-H coupling constant of 4.5 Hz and H-P coupling
constants of 331.7 (PHPh2) and 6.7 (PiPr3) Hz. The
resonance of the hydrido ligand trans-disposed to the
diphenylphosphine is observed at -10.64 ppm, also as
a doublet (J H-P ) 62.6 Hz) of triplets (J H-P′ ) 25.5 Hz)
of doublets (J H-H ) 5.5 Hz), while that corresponding
to the hydrido ligand cis-disposed to the diphenylphos-
(11) (a) Hamilton, D. G.; Crabtree, R. H. J . Am. Chem. Soc. 1988,
110, 4126. (b) Bautista, M. T.; Earl, K. A.; J ia, J .; Maltby, P. A.; Morris,
R. H.; Schweitzer, C. T.; Sella, A. J . Am. Chem. Soc. 1988, 110, 7031.
(c) Desroisiers, P. J .; Cai, L.; Lin, Z.; Richards, R.; Halpern, J . J . Am.
Chem. Soc. 1991, 113, 4173. (d) Gusev, D. G.; Kuhlman, R.; Sini, G.;
Eisenstein, O.; Caulton, K. G. J . Am. Chem. Soc. 1994, 116, 2685.
(12) Kristja´nsdo´ttir, S. S.; Norton, J . R. In Transition Metal Hy-
drides; Dedieu, A., Ed.; VCH Publishers: New York, 1991; Chapter 9.
(13) Labinger, J . A. In Transition Metal Hydrides; Dedieu, A., Ed.;
VCH Publishers: New York, 1991; Chapter 10.

3350 Organometallics, Vol. 17, No. 15, 1998
Buil et al.
1
F igu r e 5. Variable-temperature 300-MHz H NMR spec-
tra in the high-field region of [OsH(η2-H2)(CO)(PHPh2)-
(PiPr3)2]BF4 (6) in CD2Cl2.
diphenylphosphine complexes containing molecular hy-
drogen and carbon monoxide as ancillary ligands to
study weaker H‚‚‚H interactions.
F igu r e 6. Variable-temperature 300-MHz 31P{1H} NMR
spectra of [OsH(η2-H2)(CO)(PHPh2)(PiPr3)2]BF4 (6) in CD2Cl2.
1
At room temperature, the H NMR spectrum of the
solution formed by addition of 1 equiv of HBF4 to 2 in
dichloromethane-d2 shows the resonance due to the HP
proton at 6.88 ppm as a clean doublet of triplets, with
P-H coupling constants of 360.0 (P ) PHPh2) and 6.5
(P ) PiPr3) Hz. H-H coupling between the HP proton
and the hydrido ligands is not observed. In the high-
field region, the spectrum contains a broad resonance
centered at -6.80 ppm. This spectrum is temperature
dependent. Figure 5 shows the hydrido region as a
function of the temperature. At 183 and 193 K, four
broad resonances are observed, which coalesce at about
203 K to give two broad signals. Between 243 and 253
K, a second coalescence occurs and above-mentioned
broad resonance is observed. With regard to the T1
values shown in Figure 5, there is no doubt that two of
the resonances observed at 183 and 193 K correspond
to dihydrogen ligands while the other two resonances
are due to hydrido ligands.
nances for the triisopropylphosphine ligands and two
resonances for the diphenylphosphine group. Between
193 and 203 K, the signal of the diphenylphosphine
coalesce. The coalescence of resonances corresponding
to the triisopropylphosphine ligands occurs between 223
and 213 K. At 303 K, the triisopropylphosphine ligands
give rise to a doublet at 31.7 ppm while the resonance
due to diphenylphosphine is observed as a triplet at
-27.1 ppm. The P-P coupling constant is 18.6 Hz
(Figure 6).
These observations can be rationalized according to
the formation of two isomers of the cis-hydrido-dihy-
drogen complex [OsH(η2-H2)(CO)(PHPh2)(PiPr3)2]BF4
(6a and 6b in eq 5), which rapidly exchange the hydrido
and dihydrogen positions in solution at high tempera-
ture. Furthermore, the absence of nuclear spin coupling
between the hydridos and the HP hydrogen nucleus
suggests that in 6 there is no H‚‚‚H interaction.
The 31P{1H} NMR spectrum is also temperature
dependent. At 193 K, the spectrum shows two reso-

Four-Membered P-H‚‚‚H-M (M ) Os, Ru) Rings
Organometallics, Vol. 17, No. 15, 1998 3351
formed as a ca. 2:1 mixture of the cis-isomer 8 and the
trans-isomer 9 (eq 7).
The addition of acetone to dichloromethane-d2 solu-
tions of 6 produces the displacement of the dihydrogen
ligand and the formation of the solvate complex [OsH-
{(η1-OC(CH3)2}(CO)(PHPh2)(PiPr3)2]BF4 (7 in eq 6),
which can be isolated as a white solid in 68% yield by
protonation of 2 with HBF4 in acetone and the subse-
quent addition of diethyl ether.
In solution, complex 9 slowly isomerizes into 8. Thus,
after 1 week, isomer 8 was obtained as a pure crystalline
solid by crystallization in dichloromethane-diethyl
ether and characterized by an X-ray crystallographic
study. The structure has two crystallographically in-
dependent molecules of complex 8 in the asymmetric
unit. Drawings of both molecules are shown in Figure
7. Selected bond distances and angles are collected in
Table 2. In both molecules the hydrido ligand and the
HP hydrogen atom were located in the difference
Fourier maps and refined as isotropic atoms together
with the rest of the non-hydrogen atoms of the structure,
giving Os-H distances of 1.69(8) (molecule a) and 1.68-
(6) (molecule b) Å and P-H bond lengths of 1.40(5)
(molecule a) and 1.39(5) (molecule b) Å.
In the IR spectrum of 7 in Nujol, the most noticeable
features are the absorption due to the [BF4]- anion with
Td symmetry centered at 1075 cm-1, indicating that the
anion is not coordinated to the metallic center, and the
ν(CdO) band of the carbonyl group of the acetone ligand
at 1656 cm-1, suggesting that the acetone molecule
coordinates to the metal by the oxygen atom.14 The
coordination of the oxygen atom of the acetone is also
supported by the 13C{1H} NMR spectrum at 193 K,
which shows a singlet at 224.6 ppm corresponding to
the carbon atom of the carbonyl group.
The coordination geometry around the osmium atom
is octahedral, with the two triisopropylphosphine ligands
in a trans position. The perpendicular plane is formed
by the carbonyl groups mutually cis-disposed and the
hydrido and diphenylphosphine ligands also cis-dis-
posed.
In both molecules the P-H group lies in quadrants
bordered on the hydrido ligand. However, the four
atoms forming the four-membered P-H‚‚‚H-Os ring
are not coplanar, the values of the torsion angle H(01)-
Os-P(1)-H(02) are 66(3)° (molecule a) and -36(2)°
(molecule b). This seems to indicate that although there
is a H‚‚‚H interaction, it is significantly weaker than
those in 2 and 5. In agreement with this, the metal-
diphenylphosphine separation is longer in 8 than in 5
(2.429(2) and 2.433(2) Å versus 2.3264(8) Å). The
estrangement of the diphenylphosphine from the metal
produces a decrease of the steric hindrance between the
isopropyl and phenyl groups of the phosphines. As a
result, the folding of the phosphorus-metal-phospho-
rus axis in 8 is smaller than in 5 (167.96(6)° and 165.04-
(7)° versus 152.20(3)°) and the angle formed by phos-
phorus and the ipso-carbon atoms of the diphenyl-
phosphine is bigger in 8 than in 5 (105.5(3)° and 101.2-
(3)° versus 97.63(13)°). The H‚‚‚H separation also seems
to be longer in 8 than in 5 (3.04(9) and 2.83(8) Å versus
2.63(5) Å).
1
The H and 31P{1H} NMR spectra of 7 also support
the structure proposed for this compound in eq 6. The
31P{1H} NMR spectrum consists of a triplet at -18.3
ppm and a doublet at 29.3 ppm (J P-P ) 13.6 Hz), in
agreement with a diphenylphosphine ligand cis-disposed
to two equivalent triisopropylphosphines. The proposed
trans disposition of the hydrido and diphenylphosphine
1
ligands is supported by the H NMR spectrum, which
contains a doublet (J H-P ) 85.3 Hz) of triplets (J H-P′
)
23.3 Hz) at -5.88 ppm . In the low-field region, the
spectrum exhibits the expected resonance for the di-
phenylphosphine proton, which appears at 7.55 ppm as
a doublet of triplets with H-P coupling constants of
338.2 and 5.4 Hz. In addition, it should be noted that
although there are three bonds between this hydrogen
atom and the hydrido ligand, coupling between them is
not observed.
The acetone ligand of 7 can be easily displaced by
carbon monoxide. Thus, by passing a slow stream of
this gas through a dichloromethane solution of 7, the
dicarbonyl complex [OsH(CO)2(PHPh2)(PiPr3)2]BF4 was
From the X-ray analysis of the structure of 8, it is
inferred that this complex has more than one stable
conformer and that the difference in energy between
them must be small. Furthermore, it should be noted
that the main difference between molecules a and b of
8 is the disposition of the phenyl groups and the HP
(14) Esteruelas, M. A.; Lahoz, F. J .; Lo´pez, A. M.; On˜ate, E.; Oro,
L. A. Organometallics 1994, 13, 1669.

3352 Organometallics, Vol. 17, No. 15, 1998
Buil et al.
F igu r e 7. Molecular diagrams for the two independent molecules (a and b) of the cation [OsH(CO)2(PHPh2)(PiPr3)2]+ (8).
Ta ble 2. Selected Bon d Len gth s (Å) a n d An gles (d eg) for [OsH(CO)2(P HP h 2)(P iP r 3)2]BF 4 (8)a
a
b
a
b
Os-P(1)
Os-P(2)
Os-P(3)
Os-C(1)
Os-C(2)
Os-H(01)
2.429(2)
2.430(2)
2.431(2)
1.893(8)
1.939(8)
1.69(8)
2.433(2)
2.436(2)
2.438(2)
1.893(8)
1.910(9)
1.68(6)
C(1)-O(1)
C(2)-O(2)
P(1)-C(21)
P(1)-C(27)
P(1)-H(02)
H(01)-H(02)
1.148(8)
1.151(8)
1.829(7)
1.826(7)
1.40(5)
1.152(8)
1.158(9)
1.832(6)
1.834(7)
1.39(5)
3.04(9)
2.83(8)
P(1)-Os-P(2)
P(1)-Os-C(1)
P(1)-Os-C(2)
P(1)-Os-H(01)
P(1)-Os-P(3)
P(2)-Os-C(1)
P(2)-Os-C(2)
P(2)-Os-H(01)
P(2)-Os-P(3)
C(1)-Os-C(2)
C(1)-Os-H(01)
98.84(6)
168.9(2)
93.4(2)
79(3)
89.45(6)
85.0(2)
93.8(2)
86(3)
89.94(7)
166.9(2)
95.1(2)
84.3(19)
99.60(6)
84.2(2)
95.3(3)
81(2)
C(1)-Os-P(3)
85.3(2)
172(2)
94.5(2)
87(3)
124.5(2)
108.2(18)
116.7(2)
98.7(18)
105.5(3)
98.7(19)
84.1(2)
176(2)
95.3(3)
89(2)
125.6(2)
106.2(18)
119.3(2)
98.0(18)
101.2(3)
102(2)
C(2)-Os-H(01)
C(2)-Os-P(3)
H(01)-Os-P(3)
Os-P(1)-C(21)
Os-P(1)-H(02)
Os-P(1)-C(27)
C(21)-P(1)-H(02)
C(21)-P(1)-C(27)
H(02)-P(1)-C(27)
167.96(6)
96.7(3)
91(3)
165.04(7)
97.1(3)
83.2(19)
a
The first set of values (a) corresponds to the bond distances and angles of molecule a in Figure 7; the second set of values (b) corresponds
to the related parameters observed in the second independent molecule (b in Figure 7).
hydrogen atom, which produce a loss of the symmetry.
As a result, the triisopropylphosphine ligands of both
conformers are chemically inequivalent while the chemi-
cal environment of the phosphorus atom of the diphenyl-
phosphine group is always the same. Accordingly, if the
NMR spectra were recorded at different temperatures,
one should expect changes in the signal corresponding
to the triisopropylphosphine ligands in the 31P{1H}
NMR spectrum and in the resonances of the hydrido
of 378.0 and 9.3 Hz. Lowering the sample temperature
also produces broadening of both resonances.
In contrast to the NMR spectra of 8, the 31P{1H} and
1H NMR spectra of the trans-dicarbonyl isomer 9 are
temperature invariant. The 31P{1H} NMR spectrum
contains a doublet at 19.0 (J P-P ) 11.5 Hz) ppm for the
triisopropylphosphine ligands and a triplet at -42.0
1
ppm for the diphenylphosphine. In the H NMR spec-
trum, the resonance of the hydrido ligand, which is not
coupled with the HP proton, appears at -10.31 ppm as
a doublet (J H-P ) 39.9 Hz) of triplets (J H-P′ ) 20.4 Hz)
and the HP proton is observed at 7.48 ppm, also as a
doublet (J H-P ) 362.4 Hz) of triplets (J H-P′ ) 5.4 Hz).
In the trans-dicarbonyl isomer 9, which does not
possess a H‚‚‚H interaction, the free rotation of the
diphenylphosphine group around the Os-PH axis must
occur. Furthermore, the independence of its spectra (1H
and 31P{1H}) from temperature suggests that this
rotation is fast at each temperature.
1
ligand and the HP hydrogen atom in the H spectrum.
In fact, the 31P{1H} and 1H NMR spectra of 8 are
temperature dependent. At room temperature, the 31P-
{1H} NMR spectrum shows a doublet (J P-P ) 25.7 Hz)
at 15.1 ppm corresponding to the triisopropylphosphine
ligands and a triplet at -35.8 ppm for the diphenyl-
phosphine. Although decoalescence is not observed,
lowering the sample temperature leads to broadening
of the triisopropylphosphine resonance while the diphen-
ylphosphine signal does not change. In the 1H NMR
spectrum at room temperature, the hydrido ligand,
which is coupled with the HP proton, gives rise to a
doublet (J H-P ) 27.9 Hz) of triplets (J H-P′ ) 18.0 Hz) of
doublets (J H-H ) 4.5 Hz) at -8.10 ppm. The resonance
of the HP proton appears at 7.19 ppm, also as a doublet
of triplets of doublets but with H-P coupling constants
In contrast to the spectra of 9, the 1H and 31P{1H}
NMR spectra of 8 are temperature dependent. The
independence of the spectra of 9 from temperature
shows that the broadening observed in the Os-H and
PH signals in the 1H NMR spectrum and the broadening
of the signal of the triisopropylphosphine in the 31P{1H}

Four-Membered P-H‚‚‚H-M (M ) Os, Ru) Rings
Organometallics, Vol. 17, No. 15, 1998 3353
Sch em e 1
constants between 74.4 and 93.6 (PHPh2) Hz and
between 22.5 and 23.7 (PiPr3) Hz. H-H coupling
between these hydridos and the HP hydrogen atoms is
not observed.
Con clu sion
This study has revealed that in the solid state as well
as in solution an intramolecular interaction between
nucleophilic and electrophilic hydrogen atoms of a
transition-metal complex can take place, even when the
separation between the hydrogen atoms is more than
2.4 Å. Because the interaction is electrostatic in char-
acter, it can be modulated by tuning the nucleophilicity
and electrophilicity of the hydrogen atoms.
Although the interaction does not impose the stereo-
chemistry of a particular complex, it favors the forma-
tion of determined conformers. Some unusual distor-
tions of the structure of the complex can also be
rationalized on the basis of this interaction. In solution,
it reduces the dynamic properties of the complexes, in
particular those of the ligands supporting the interac-
tion.
In conclusion, we report the characterization of a new
intramolecular H‚‚‚H interaction (long distance H‚‚‚H
interaction) which for transition-metal hydrido com-
pounds has a significant influence in the structural
parameters of the molecule and, in solution, in the
dynamic behavior of the ligands.
NMR spectrum of 8 can be only due to a hindered
rotation around the Os-PH bond. Thus, the compari-
son between the spectra of 8 and 9 indicates that in 8
the H‚‚‚H interaction persists in solution and, therefore,
the fluxional process in the cis-dicarbonyl isomer most
probably consists of an oscillation of the diphenylphos-
phine group around the Os-PH axis. In addition,
comparison of the structural parameters of 8 and 5
clearly shows that the H‚‚‚H interaction in 5 is stronger
than in 8. So, the independence of the spectra (1H and
31P{1H}) of 2 and 5 with the temperature can be only
rationalized by accepting that in these compounds the
rotation of the diphenylphosphine around the M-PH
axis is blocked.
The T1 values for the hydrido resonances of 8 and 9
were determined over the range of 293-188 K. The T1-
(min) values at 300 MHz for both resonances (271 ms
for the hydrido ligand of 8 and 288 ms for the hydrido
ligand of 9) were found at the same temperature, 198
K. Assuming that the excess relaxation rate for the
hydrido resonance of 8 (0.22 s-1) is a result of the
proximity of the HP proton in this compound, we can
estimate a H‚‚‚H separation of 2.9 Å,10 which is the
average value of those found by X-ray diffraction (3.04-
(9) and 2.83(8) Å), in agreement with the proposed
oscillation.
Inside of this range, we attempted to tune the H‚‚‚H
interaction by replacement of one carbonyl group by
σ-donor ligands. Thus, we carried out the reactions of
the acetone complex 7 with acetonitrile, lithium phen-
ylacetylide, and potassium bromide (Scheme 1). Un-
fortunately, in the three new compounds, [OsH(CO)-
(CH3CN)(PHPh2)(PiPr3)2]BF4 (10), OsH(C2Ph)(CO)-
(PHPh2)(PiPr3)2 (11), and OsHBr(CO)(PHPh2)(PiPr3)2
(12), the hydrido and diphenylphosphine ligands are
mutually trans-disposed and a H‚‚‚H interaction is not
observed. This suggests that although the H‚‚‚H inter-
action can contribute to the stability of a particular
complex, it is not sufficient to determine its stereochem-
istry.
Exp er im en ta l Section
Gen er a l Con sid er a tion s. 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 (1),15 OsH(η2-H2BH2)(CO)-
(PiPr3)2 (3),16 and RuH(η2-H2BH2)(CO)(PiPr3)2 (5)16 were pre-
pared by a published method.
P h ysica l Mea su r em en ts. NMR spectra were recorded on
a Varian UNITY 300 or on a Bruker ARX 300 spectrometer
at room temperature unless otherwise stated. Chemical shifts
are expressed in parts per million, upfield from Si(CH3)4 (1H,
13C{1H}) and 85% H3PO4 (31P{1H} NMR spectra). Coupling
1
constants J and N (N ) J (HP) + J (HP′) for H; and N ) J (CP)
+ J (CP′) for 13C) are given in hertz. The probe temperature
of the NMR spectrometers was calibrated at each temperature
against a methanol standard. The T1 experiments were
performed on a Varian UNITY 300 spectrometer or on a
Bruker AXR 300 spectrometer with a standard 180°-τ-90°
pulse sequence. T1 values are given in milliseconds (ms).
Infrared spectra were recorded on a Nicolet 550 spectrometer
using Nujol mulls on polyethylene sheets. C and H analyses
were carried out on a Perkin-Elmer 240C microanalyzer.
P r ep a r a tion of OsH2(CO)(P HP h 2)(P iP r 3)2 (2). The com-
plex can be prepared by two different procedures.
(a) A solution of OsH2(η2-CH2dCHEt)(CO)(PiPr3)2 (ca. 160
mg, 0.28 mmol) in 5 mL of pentane was treated with PHPh2
(59 µL, 0.34 mmol). The mixture was stirred for 30 min 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: 125
mg (62%).
Complexes 10-12 were obtained in 50-70% yield as
white solids. The proposed trans disposition of the
hydrido and diphenylphosphine ligands is supported by
(15) Albe´niz, M. J .; Buil, M. L.; Esteruelas, M. A.; Lo´pez, A. M.; Oro,
L. A.; Zeier, B. Organometallics 1994, 13, 3746.
(16) Werner, H.; Esteruelas, M. A.; Meyer, U.; Wrackmeyer, B.
Chem. Ber. 1987, 120, 11.
1
the H NMR spectra, which contain doublets of triplets
between -7.56 and -9.07 ppm with H-P coupling

3354 Organometallics, Vol. 17, No. 15, 1998
Buil et al.
(b) To a stirred suspension of OsH(η2-H2BH2)(CO)(PiPr3)2
(3) (115 mg, 0.21 mmol) in 5 mL of methanol was added PHPh2
(36 µL, 0.21 mmol). The mixture was stirred for 1 h at room
temperature. A white solid was formed. The solution was
decanted, and the white solid was washed with methanol
and dried in vacuo. Yield: 102 mg (67%). Anal. Calcd for
PCHCH3), -5.88 (dt, 1H, J H-P ) 85.3 Hz, J H-P′ ) 23.3 Hz, Os-
H). 13C{1H} NMR (75.43 MHz, 193 K, CD2Cl2): δ 224.6 (s,
{η1-OC(CH3)2}), 182.1 (dt, J C-P ) 8.1 Hz, J C-P′ ) 7.1 Hz, CO),
132.4 (d, J C-P ) 9.4 Hz, Cipso), 131.8 (s, p-C6H5), 131.1 (s,
m-C6H5), 128.8 (d, J C-P ) 8.7 Hz, o-C6H5), 30.8 (s, {η1-OC-
(CH3)2}), 23.4 (br, PCHCH3), 19.4 (s br, PCHCH3), 18.1 (s br,
PCHCH3). 31P{1H} NMR (121.4 MHz, CD2Cl2): δ 29.3 (d, J P-P′
) 13.6 Hz), -18.3 (t, J P-P′ ) 13.6 Hz).
C
31H55OOsP3: C, 51.22; H, 7.62. Found: C, 50.71; H, 8.10.
IR (Nujol, cm-1): ν(PPh2-H) 2334, ν(Os-H) 1984, ν(CO)
1853. 1H NMR (300 MHz, C6D6): δ 7.72 (vt, 4H, N ) J H-H
+
P r ep a r a tion of th e Isom er ic Mixtu r e cis-, tr a n s-[OsH-
(CO)2(P HP h 2)(P iP r 3)2]BF 4 (8, 9). CO was bubbled through
a stirred solution of [OsH{η1-OC(CH3)2}(CO)(PHPh2)(PiPr3)2]BF4
(7) (100 mg, 0.12 mmol) in 6 mL of CH2Cl2 for 90 min. The
solution was concentrated to ca. 0.5 mL, and after the addition
of diethyl ether a white solid was formed. The solution was
decanted, and the white solid was washed with diethyl ether
and dried in vacuo. The solid obtained was a mixture of two
isomers 8:9 in a 2:1 molar ratio.Yield: 91 mg (90%). Anal.
Calcd for C32H54BF4O2OsP3: C, 45.72; H, 6.47. Found: C,
46.04; H, 6.42.
J H-P ) 17.4 Hz, o-C6H5), 7.44 (dtd, 1H, J H-P ) 331.7 Hz, J H-P′
) 6.7 Hz, J H-H ) 4.5 Hz, PHPh2), 7.07 (ddd, 4H, J H-H ) J H-H′
) 7.0 Hz, J H-P ) 1.5 Hz, m-C6H5), 6.98 (dd, 2H, J H-H ) 7.0
Hz, J H-H′ ) 1.4 Hz, p-C6H5), 1.94 (m, 6H, PCHCH3), 1.19 (dvt,
18H, J H-H ) 7.1 Hz, N ) 13.5 Hz, PCHCH3), 1.09 (dvt, 18H,
J H-H ) 6.9 Hz, N ) 12.6 Hz, PCHCH3), -9.94 (tddd, 1H, J H-P
) 21.7 Hz, J H-P′ ) 21.4 Hz, J H-H ) 5.5 Hz, J H-H′ ) 4.5 Hz,
Os-H), -10.64 (dtd, 1H, J H-P ) 62.6 Hz, J H-P′ ) 25.5 Hz, J H-H
) 5.5 Hz, Os-H). 31P{1H} NMR (121.4 MHz, C6D6): δ 35.1 (d,
J P-P′ ) 13.9 Hz), -18.6 (t, J P-P′ ) 13.9 Hz).
P r ep a r a tion of Ru H2(CO)(P HP h 2)(P iP r 3)2 (5). A stirred
suspension of RuH(η2-H2BH2)(CO)(PiPr3)2 (4) (120 mg, 0.26
mmol) in 5 mL of methanol was treated with PHPh2 (45 µL,
0.26 mmol). The mixture was stirred for 4 h at room
temperature. A white solid was formed. The solution was
decanted, and the white solid was washed with methanol
and dried in vacuo. Yield: 113 mg (68%). Anal. Calcd for
IR (Nujol, cm-1): ν(PPh2-H) 2325, ν(Os-H) 2000, ν(CO)
1
1980, 1950, 1910. Spectroscopic data of 8(cis) H NMR (300
MHz, CDCl3): δ 7.55-7.37 (m, 10H, C6H5), 7.19 (dtd, 1H, J H-P
) 378.0 Hz, J H-P′ ) 9.3 Hz, J H-H′ ) 5.4 Hz, PHPh2), 2.35 (m,
6H, PCHCH3), 1.21 (dvt, 18H, J H-H ) 7.2 Hz, N ) 14.4 Hz,
PCHCH3), 1.11 (dvt, 18H, J H-H ) 6.9 Hz, N ) 12.9 Hz,
PCHCH3), -8.10 (dtd, 1H, J H-P ) 27.9 Hz, J H-P′ ) 18.0 Hz,
J H-H′ ) 4.5 Hz). 31P{1H} NMR (121.4 MHz, CDCl3): δ 15.1
(d, J P-P′ ) 25.7 Hz), -35.8 (t, J P-P′ ) 25.7 Hz). Spectroscopic
C
31H55OP3Ru: C, 58.38; H, 8.69. Found: C, 58.46; H, 8.11.
IR (Nujol, cm-1): ν(PPh2-H) 2336, ν(Ru-H) 1949, ν(CO)
1
1845. 1H NMR (300 MHz, C6D6): δ 7.74 (vt, 4H, N ) J H-P
J H-H ) 18.3 Hz, o-C6H5), 7.07 (vt, 4H, N ) J H-H + J H-H′
+
)
data of 9(tr a n s) H NMR (300 MHz, CDCl3): δ 7.58-7.44 (m,
10H, C6H5), 7.48 (dt, 1H, J H-P ) 362.4 Hz, J H-P′ ) 5.4 Hz,
PHPh2), 2.23 (m, 6H, PCHCH3), 1.16 (dvt, 36H, J H-H ) 7.5
Hz, N ) 14.7 Hz, PCHCH3), -10.31 (dt, 1H, J H-P ) 39.9 Hz,
J H-P′ ) 20.4 Hz, Os-H). 31P{1H} NMR (121.4 MHz, CDCl3):
δ 19.0 (d, J P-P′ ) 11.5 Hz), -42.0 (t, J P-P′ ) 11.5 Hz). 13C{1H}
NMR (75.43 MHz, CDCl3) of 8 and 9: δ 185.3 (dt, J C-P ) 10.0
Hz, J C-P′ ) 9.1 Hz, CO), 184.7 (dt, J C-P ) 10.5 Hz, J C-P′ ) 9.0
Hz, CO), 179.4 (dt, J C-P ) 71.5 Hz, J C-P′ ) 10.2 Hz, CO), 133.3
(d, J C-P ) 9.8 Hz, Cipso), 132.6 (d, J C-P ) 9.8 Hz, Cipso), 131.8,
131.4, 130.8, 130.2, 129.5, 129.4, 129.25, 120.1, 127.4 (all s,
C6H5), 27.4 (vt, N ) 28.5 Hz, PCHCH3), 26.9 (vt, N ) 28.1 Hz,
PCHCH3), 19.5 (s, PCHCH3), 19.2 (s, PCHCH3), 19.0 (s,
PCHCH3).
14.4 Hz, m-C6H5), 6.99 (d, 2H, J H-H ) 7.1 Hz, p-C6H5), 6.88
(dtd, 1H, J H-P ) 315.5 Hz, J H-P′ ) 7.8 Hz, J H-H ) 4.1 Hz,
PHPh2), 1.88 (m, 6H, PCHCH3), 1.23 (dvt, 18H, J H-H ) 7.2
Hz, N ) 13.5 Hz, PCHCH3), 1.12 (dvt, 18H, J H-H ) 6.8 Hz, N
) 12.7 Hz, PCHCH3), -8.51 (dtdd, 1H, J H-P ) 28.2 Hz, J H-P′
) 16.8 Hz, J H-H ) 6.1 Hz, J H-H′ ) 4.1 Hz, Ru-H), -9.58 (dtd,
1H, J H-P ) 77.9 Hz, J H-P′ ) 25.7 Hz, J H-H ) 6.1 Hz, Ru-H).
31P{1H} NMR (121.4 MHz, C6D6): δ 74.9 (d, J P-P′ ) 19.3 Hz),
20.2 (t, J P-P′ ) 19.3 Hz).
P r ep a r a t ion of [OsH (η2-H 2)(CO)(P H P h 2)(P iP r 3)2]BF 4
(6). A solution of OsH2(CO)(PHPh2)(PiPr3)2 (2) (10 mg, 0.014
mmol) in 0.5 mL of CD2Cl2 in a NMR tube was treated with
HBF4‚OEt2 (2 µL, 0.014 mmol). The NMR tube was sealed
under argon.
1H NMR (300 MHz, 293 K, CD2Cl2): δ 7.52-7.41 (m, 10H,
C6H5), 6.59 (dt, 1H, J H-P ) 361.5 Hz, J H-P′ ) 6.5 Hz, PHPh2),
2.19 (m, 6H, PCHCH3), 1.20 (dvt, 18H, J H-H ) 6.0 Hz, N )
13.2 Hz, PCHCH3), 1.16 (dvt, 18H, J H-H ) 6.6 Hz, N ) 13.8
Hz, PCHCH3), -6.67 (br, 3H, Os-H3). 1H NMR (300 MHz,
183 K, CD2Cl2): δ 7.88-7.32 (br, 20H, C6H5), 6.38, 6.06 (both
br, each 1H, PHPh2), 2.48-2.08 (br, 12H, PCHCH3), 1.55-
0.80 (br, 72H, PCHCH3), -4.75 (br, 2H, Os(η2-H2)), -6.44 (br,
1H, Os-H), -7.15 (br, 2H, Os(η2-H2)), -7.92 (br, 1H, Os-H).
31P{1H} NMR (121.4 MHz, CD2Cl2): δ 31.7 (d, J P-P ) 18.6 Hz),
-27.1 (t, J P-P ) 18.6 Hz).
P r ep a r a tion of [OsH(NCCH3)(CO)(P HP h 2)(P iP r 3)2]BF 4
(10). A solution of [OsH{η1-OC(CH3)2}(CO)(PHPh2)(PiPr3)2]BF4
(7) (120 mg, 0.14 mmol) in 5 mL of CH2Cl2 was treated with
CH3CN (7.2 µL, 0.14 mmol). The mixture was stirred for 1 h
at room temperature. The solution was concentrated to ca.
0.5 mL, and after the addition of diethyl ether, a white solid
was formed. The solution was decanted, and the white solid
was washed with diethyl ether and dried in vacuo. Yield: 84
mg (70%). Anal. Calcd for C33H57BF4ONOsP3: C, 46.43; H,
6.73; N, 1.64. Found: C, 46.32; H, 7.12; N, 1.62.
IR (Nujol, cm-1): ν(PPh2-H) 2333, ν(Os-H) 2097(s), ν(CO)
1926 (s), ν(BF4) 1050. 1H NMR (300 MHz, CD2Cl2): δ 7.61-
7.40 (m, 10H, C6H5), 7.51 (dt, 1H, J H-P ) 342.9 Hz, J H-P′
)
P r epar ation of [OsH{η1-OC(CH3)2}(CO)(P HP h 2)(P iP r 3)2]-
BF 4 (7). A solution of OsH2(CO)(PHPh2)(PiPr3)2 (2) (100 mg,
0.14 mmol) in 5 mL of acetone was treated with HBF4‚OEt2
(19.2 µL, 0.14 mmol). The mixture was stirred for 1 h at room
temperature. The solution was concentrated to ca. 0.5 mL,
and after the addition of diethyl ether, a white solid was
formed. The solution was decanted, and the white solid was
washed with diethyl ether and dried in vacuo. Yield: 83 mg
(68%). Anal. Calcd for C34H60BF4O2OsP3: C, 46.89; H, 6.94.
Found: C, 46.65; H, 6.86.
5.8 Hz, PHPh2), 2.51 (s, 3H, NCCH3), 2.35 (m, 6H, PCHCH3),
1.19 (dvt, 36H, J H-H ) 6.9 Hz, N ) 13.5 Hz, PCHCH3), -8.26
(dt, 1H, J H-P ) 74.7 Hz, J H-P′ ) 22.5 Hz, Os-H). 31P{1H} NMR
(121.4 MHz, CD2Cl2): δ 19.5 (d, J P-P′ ) 13.0 Hz), -30.0 (t,
J P-P′ ) 13.0 Hz).
P r ep a r a tion of OsH(CtCP h )(CO)(P HP h 2)(P iP r 3)2 (11).
A stirred suspension of [OsH{η1-OC(CH3)2}(CO)(PHPh2)(PiPr3)2]-
BF4 (7) (100 mg, 0.12 mmol) in 5 mL of toluene was treated
with PhCtCLi (13.7 mg, 0.13 mmol). The mixture was stirred
for 2 h at room temperature. The mixture was filtered through
Kieselguhr. The resulting solution was concentrated to ca. 0.5
mL, and after the addition of methanol, a white solid was
formed. The solution was decanted, and the white solid was
washed with methanol and dried in vacuo. Yield: 51 mg
(50%). Anal. Calcd for C39H59OOsP3‚CH3OH: C, 55.92; H,
7.39. Found: C, 55.60; H, 7.08.
IR (Nujol, cm-1): ν(PPh2-H) 2333 ν(Os-H) 2061(s), ν(CO)
1915 (s), ν(OC(CH3)2) 1656, ν(BF4) 1075. 1H NMR (300 MHz,
CD2Cl2): δ 7.60-7.44 (m, 10H, C6H5), 7.55 (dt, 1H, J H-P
)
338.2 Hz, J H-P′ ) 5.4 Hz, PHPh2), 2.35 (m, 6H, PCHCH3), 2.14
(s, 6H, OC(CH3)2), 1.15 (dvt, 18H, J H-H ) 6.8 Hz, N ) 13.1
Hz, PCHCH3), 1.10 (dvt, 18H, J H-H ) 7.1 Hz, N ) 14.0 Hz,

Four-Membered P-H‚‚‚H-M (M ) Os, Ru) Rings
Organometallics, Vol. 17, No. 15, 1998 3355
IR (Nujol, cm-1): ν(PPh2-H) 2330, ν(Os-H) 2093(s), ν(CO)
1898 (s), ν(CtC) 1591. 1H NMR (300 MHz, C6D6): δ 7.91 (vt,
4H, N ) J H-H + J H-P ) 18.1 Hz, o-P(C6H5)), 7.61 (dt, 1H, J H-P
) 342.1 Hz, J H-P′ ) 5.4 Hz, PHPh2), 7.54 (dd, 2H, J H-H ) 7.2
Hz, J H-H′ < 1 Hz, o-C6H5), 7.21-6.96 (m, 9H, C6H5), 2.45 (m,
6H, PCHCH3), 1.24 (dvt, 18H, J H-H ) 6.9 Hz, N ) 12.9 Hz,
PCHCH3), 1.18 (dvt, 18H, J H-H ) 7.0 Hz, N ) 13.3 Hz,
PCHCH3), -9.07 (dt, 1H, J H-P ) 74.4 Hz, J H-P′ ) 23.7 Hz).
13C{1H} NMR (75.43 MHz, C6D6): δ 189.8 (dt, J C-P ) 9.1 Hz,
J C-P′ ) 7.5 Hz, CO), 137.7 (d, J C-P ) 33.9 Hz, Cipso), 134.3-
124.4 (C6H5), 112.2 (s, Cât), 108.6 (dt, J C-P ) J C-P′ ) 17.4 Hz,
CRt), 26.7 (vt, N ) 26.3 Hz, PCHCH3), 20.2 (s, PCHCH3), 20.2
(s, PCHCH3). 31P{1H} NMR (121.4 MHz, C6D6): δ 16.8 (d, J P-P′
) 13.4 Hz), -31.6 (t, J P-P′ ) 13.4 Hz).
Ta ble 3. Cr ysta l Da ta a n d Da ta Collection a n d
Refin em en t P a r a m eter s for Ru H2(CO)(P HP h 2)-
(P iP r 3)2 (5) a n d [OsH(CO)2(P HP h 2)(P iP r 3)2]BF 4 (8)
5
8
formula
mol wt
C
31H55OP3Ru
C32H54BF4O2Os
840.67
637.73
color and habit
colorless,
colorless,
prismatic block
irregular block
cryst size, mm
symmetry
space group
a, Å
b, Å
c, Å
0.52 × 0.45 × 0.32 0.32 × 0.28 × 0.22
monoclinic
P21/c
monoclinic
P21/c
22.419(3)
9.173(1)
17.084(2)
108.980(10)
3322.3(7)
4
17.487(2)
12.293(1)
34.284(3)
99.232(7)
7274.5(12)
8
â, deg
P r ep a r a tion of OsHBr (CO)(P HP h 2)(P iP r 3)2 (12).
A
V, Å3
stirred suspension of [OsH{η1-OC(CH3)2}(CO)(PHPh2)(PiPr3)2]-
BF4 (7) (150 mg, 0.17 mmol) in 5 mL of THF was treated with
KBr (23 mg, 0.19 mmol). The mixture was stirred for 5 h at
room temperature. The mixture was filtered through Kiesel-
guhr. The resulting solution was concentrated to dryness, and
after the addition of methanol, a white solid was formed. The
solution was decanted, and the white solid was washed with
methanol and dried in vacuo. Yield: 51 mg (50%). Anal.
Calcd for C31H54OBrOsP3: C, 46.21; H, 6.75. Found: C, 45.81;
H, 6.20.
Z
D
calc, g cm-3
1.275
1.535
µ, mm-1
0.64
3.69
scan type
w/2θ
w
2θ range, deg
temp, K
4 e 2θ e 50
4 e 2θ e 50
173
173
no. of data collcd
no. of unique data
6048
14 560
5865(Rint ) 0.0270) 12 769(Rint ) 0.0354)
no. of params refined 350
792
a
R1 [F2 > 2σ(F2)]
0.0321
0.0909
1.043
0.0377
0.0748
0.825
b
wR2 [all data]
IR (Nujol, cm-1): ν(PPh2-H) 2355, ν(Os-H) 2091(s), ν(CO)
1902 (s). 1H NMR (300 MHz, C6D6): δ 7.88 (vt, 4H, N ) J H-H
+ J H-P ) 18.3 Hz, o-C6H5), 7.85 (dt, 1H, J H-P ) 345.9 Hz, J H-P′
) 4.8 Hz, PHPh2), 7.07 (dd, 4H, J H-H ) J H-H′ ) 7.2 Hz,
m-C6H5), 7.21 (d, 2H, J H-H ) 6.9 Hz, p-C6H5), 2.58 (m, 6H,
PCHCH3), 1.25 (dvt, 18H, J H-H ) 6.9 Hz, N ) 13.2 Hz,
PCHCH3), 1.11 (dvt, 18H, J H-H ) 6.9 Hz, N ) 12.9 Hz,
PCHCH3), -7.56 (dt, 1H, J H-P ) 93.6 Hz, J H-P′ ) 23.4 Hz,
Sc [all data]
R1(F) ) ∑||Fo| - |Fc||/∑|Fo|. wR2(F2) ) {∑[w(Fo - Fc2)2]/
a
b
2
∑[w(Fo2)2]}1/2
.
c Goof ) S ) {∑[w(Fo - Fc2)2]/(n - p)}1/2, where n
2
is the number of reflections and p is the number of refined
parameters.
This group was refined with common restrained B-F and F-F
distances (1.20(1) and 1.96(1) Å). Anisotropic parameters were
used in the last cycles of refinement for all non-hydrogen
atoms. The hydrogen atoms were observed (hydrido and
hydrogen atoms bonded to P) or calculated and refined riding
on carbon atoms with common isotropic thermal parameters.
Atomic scattering factors, corrected for anomalous dispersion
for Ru, Os, and P, were implemented by the program. The
refinements converge to R1 [F2 > 2σ(F2)] ) 0.0321 (5) or 0.0377
(8) and wR2 [all data] ) 0.0909 (5) or 0.0748 (8), with weighting
parameters x ) 0.0503, y ) 1.25 (5) and x ) 0.0264, y ) 0 (8).
Os-H). 31P{1H} NMR (121.4 MHz, C6D6): δ 15.0 (d, J P-P′
14.2 Hz), -29.2 (t, J P-P′ ) 14.2 Hz).
)
Cr ysta l Da ta for 5 a n d 8. Crystals suitable for the X-ray
diffraction study were obtained by slow diffusion of methanol
into a concentrated solution of 5 in toluene or from dichlo-
romethane/ether for 8. A summary of crystal data and
refinement parameters is reported in Table 3. The colorless
crystals (0.52 × 0.45 × 0.32 mm (5) and 0.32 × 0.28 × 0.22
mm (8)) were glued on a glass fiber and mounted on a Siemens
STOE AED (5) or Siemens P4 four-circle (8) diffractometer,
with graphite-monochromated Mo KR radiation. A group of
46 reflections in the range 20° e 2θ e 40° (5) or 52 reflections
in the range 30° e 2θ e 42° (8) was carefully centered at 173
K and used to obtain by the unit cell dimensions least-squares
methods. Three standard reflections were monitored at
periodic intervals thoughout data collection: no significant
variations were observed. All data were corrected for absorp-
tion using a semiempirical method.17 The structures were
solved by Patterson (Ru or Os atoms, SHELXTL-PLUS18) and
conventional Fourier techniques and refined by full-matrix
Ack n ow led gm en t. We thank the DGICYT (Project
PB95-0806, Programa de Promocio´n General del Cono-
cimiento) for financial support.
Su p p or tin g In for m a tion Ava ila ble: Tables of atomic
coordinates and equivalent isotropic displacement coefficients,
anisotropic thermal parameters, experimental details of the
X-ray study, bond distances and angles, and least-squares
planes for 5 and 8 (30 pages). Ordering information is given
on any current masthead page.
-
least-squares on F2 (SHELXL9319). The BF4 anion of one of
the independent molecules of 8 was found to be disordered.
OM9803218
(17) North, A. C. T.; Phillips, D. C.; Mathews, F. S. Acta Crystallogr.
1988, A24, 351.
(18) Sheldrick, G. SHELXTL-PLUS; Siemens Analitical X-ray In-
struments Inc.: Madison WI, 1990.
(19) Sheldrick, G. SHELXL-93. Program for Crystal Structure
Refinement; Institu¨t fu¨r Anorganische Chemie der Universita¨t: Go¨t-
tingen, Germany, 1993.