Preparation and characterization of ruthenium(II) monophosphaferrocene complexes. Reactivity, dynamic solution behavior, and X-ray structure of [RuH2(η2-H2)(PCy3) 2(2-phenyl-3,4-dimethylphosphaferrocene)]

Article abstract of DOI:10.1021/ic001404v

The bis(dihydrogen) complex RuH₂(H₂)₂(PCy₃)₂ (1) reacts with 2-phenyl-3,4-dimethylphosphaferrocene (L₁) to give RuH₂(H₂)(PCY₃)₂(L₁) (2). This dihydride-dihydrogen complex has been characterized by X-ray crystallography and variable-temperature ¹H and ³¹p NMR spectroscopy. The exchange between the dihydrogen ligand and the two hydrides is characterized by a ΔG of 46.2 kJ/mol at 263 K. H/D exchange is readily observed when heating a C₇D₈ solution of 2 (J_H-D = 30 Hz). The H₂ ligand in 2 can be displaced by ethylene or carbon monoxide leading to the corresponding ethylene or carbonyl complexes. The reaction of 1 with 2 equiv of 3,4-dimethylphosphaferrocene (L₂) yields the dihydride complex RuH₂(PCy₃)₂(L₂)₂ (5).

Full text of DOI:10.1021/ic001404v

3034
Inorg. Chem. 2001, 40, 3034-3038
Preparation and Characterization of Ruthenium(II) Monophosphaferrocene Complexes.
Reactivity, Dynamic Solution Behavior, and X-ray Structure of
[RuH2(η2-H2)(PCy3)2(2-phenyl-3,4-dimethylphosphaferrocene)]
Andrew J. Toner,†,‡ Bruno Donnadieu,†,§ Sylviane Sabo-Etienne,*,† Bruno Chaudret,†
Xavier Sava,| Franc¸ois Mathey,| and Pascal Le Floch|
Laboratoire de Chimie de Coordination du CNRS, 205 Route de Narbonne,
31077 Toulouse Cedex 04, France, and Laboratoire “He´te´roe´le´ments et Coordination”,
UMR CNRS 7653, Ecole Polytechnique, 91128 Palaiseau Cedex, France
ReceiVed December 12, 2000
The bis(dihydrogen) complex RuH2(H2)2(PCy3)2 (1) reacts with 2-phenyl-3,4-dimethylphosphaferrocene (L1) to
give RuH2(H2)(PCy3)2(L1) (2). This dihydride-dihydrogen complex has been characterized by X-ray crystallography
1
and variable-temperature H and 31P NMR spectroscopy. The exchange between the dihydrogen ligand and the
two hydrides is characterized by a ∆Gq of 46.2 kJ/mol at 263 K. H/D exchange is readily observed when heating
a C7D8 solution of 2 (JH-D ) 30 Hz). The H2 ligand in 2 can be displaced by ethylene or carbon monoxide
leading to the corresponding ethylene or carbonyl complexes. The reaction of 1 with 2 equiv of 3,4-
dimethylphosphaferrocene (L2) yields the dihydride complex RuH2(PCy3)2(L2)2 (5).
Introduction
orthometalated species in the catalytic cycle postulated by
Murai.2 We have also reported the orthometalation of 2-phe-
nylpyridine by 1 leading to a hydrido, dihydrogen complex
[RuH(H2)(PCy3)2(o-C6H4py)] exhibiting quantum mechanical
exchange couplings between the cis-disposed hydride and
dihydrogen ligands.3 The protonation of the corresponding Pi-
Pr3 complex with 1 equiv of HBArf·2Et2O (BArf ) [3,5-(CF3)2-
(C6H3)4B]) affords a novel hydrido, dihydrogen complex
[RuH(H2)(PiPr3)2(o-C6H5py)][BArf] containing a labile, agostic
aryl C-H bond. This complex was shown to be in equilibrium
with a metalated bis(dihydrogen) species.5
Widespread research in the activation of C-H bonds is
manifest in the wealth of publications found in the current
literature.1 More particularly, the activation of aryl C-H bonds
has been recently exploited by Murai et al. to achieve the
functionalization of a wide variety of aromatic compounds via
the catalytic formation of carbon-carbon bonds.2
Our current interest has been stimulated by mechanistic
studies on the catalytic alkylation of aryl-substituted ketones
(benzophenone and acetophenone).3 We have found that cata-
lytic ethylene insertion can be achieved by the bis(dihydrogen)
complex RuH2(H2)2(PCy3)2 (1),4 at room temperature. Similar
catalytic activity was observed in the presence of the pre-isolated
orthometalated complexes RuH(H2)(PCy3)2(L) (L ) acetophen-
ato or benzophenato), confirming the presence of intermediary
In light of these results we have extended the scope of
possible substrates suitable for activation, but which retain the
propensity to undergo orthometalation reactions, to include
ligands with more diverse functionalities. Substituted mono-
phosphaferrocenes offer us this possibility as, in addition to other
reactive sites, they retain their lone pair donor capability.6
Recently these complexes, which incorporate an sp2-hybridized
phosphorus atom, have been the subject of intense research work
as a result of their inherent planar chirality.7 Some of us8 have
recently prepared the first derivatives of Rh(I) and Ir(I)
containing nonchiral monophosphaferrocenes with the aim of
probing the catalytic activity in this new class of compound.
Herein we report the reactivity of 1, which is already known to
exhibit a wide variety of chemical transformations,3-5,9 with
2-phenyl-3,4-dimethylphosphaferrocene (L1), in which a phenyl
substituent is readily available for orthoruthenation. We have
also considered the chemistry of the non-R-substituted 3,4-
dimethylphosphaferrocene (L2) with the same ruthenium precur-
sor to provide the first examples of ruthenium polyhydride
complexes containing monophosphaferrocenes.
* To whom correspondence should be addressed. E-mail: sabo@lcc-
toulouse.fr.
† Laboratoire de Chimie de Coordination du CNRS.
‡ Current address: Anorganisch-chemisches Institut, Universita¨t Zu¨rich,
Winterthurerstrasse 190, CH-8057 Zu¨rich, Switzerland.
§ X-ray crystal structure analysis.
| Laboratoire “He´te´roe´le´ments et Coordination”.
(1) Shilov, A. E.; Shul’pin, G. B. Chem. ReV. 1997, 97, 2879 and
references therein.
(2) (a) Murai, S.; Kakiuchi, F.; Sekine, S.; Tanaka, Y.; Kamatani, A.;
Sonoda, M.; Chatani, N. Nature 1993, 366, 529. (b) Kakiuchi, F.;
Sekine, S.; Tanaka, Y.; Kamatani, A.; Sonoda, M.; Chatani, N.; Murai,
S. Bull. Chem. Soc. Jpn. 1995, 68, 62. (c) Kakiuchi, F.; Tanaka, Y.;
Sato, T.; Chatani, N.; Murai, S. Chem. Lett. 1996, 111. (d) Kakiuchi,
F.; Sonoda, M.; Tsujimoto, T.; Chatani, N.; Murai, S. Chem. Lett.
1999, 1083. (e) Chatani, N.; Ie, Y.; Kakiuchi, F.; Murai, S. J. Am.
Chem. Soc. 1999, 121, 8645. (f) Matsubara, T.; Koga, N.; Musaev,
D. G.; Morokuma, K. J. Am. Chem. Soc. 1998, 120, 12692.
(3) (a) Guari, Y.; Sabo-Etienne, S.; Chaudret, B. J. Am. Chem. Soc. 1998,
120, 4228. (b) Guari, Y.; Sabo-Etienne, S.; Chaudret, B. Eur. J. Inorg.
Chem. 1999, 1047.
(4) (a) Chaudret, B.; Poilblanc, R. Organometallics 1985, 4, 1722. (b)
Borowski, A. F., Sabo-Etienne, S.; Christ, M. L., Donnadieu, B.;
Chaudret, B. Organometallics 1996, 15, 1427. (c) Borowski, A. F.;
Donnadieu, B.; Daran, J. C.; Sabo-Etienne, S.; Chaudret, B. Chem.
Commun. 2000, 543, 1697.
(5) Toner, A. J.; Grundemann, S.; Clot, E.; Limbach, H.-H.; Donnadieu,
B.; Sabo-Etienne, S.; Chaudret, B. J. Am. Chem. Soc. 2000, 122, 6777.
(6) Mathey, F. Coord. Chem. ReV. 1994, 137, 1.
10.1021/ic001404v CCC: $20.00 © 2001 American Chemical Society
Published on Web 05/19/2001

Ruthenium(II) Monophosphaferrocene Complexes
Inorganic Chemistry, Vol. 40, No. 13, 2001 3035
Scheme 1
Figure 1. ZORTEP view (50% probability ellipsoids) of [RuH2(η2-
H2)(PCy3)2(2-phenyl-3,4-dimethylphosphaferrocene)] (2). Selected bond
lengths (Å): Ru-P(1), 2.3271(10); Ru-P(2), 2.3281(10); Ru-P(3),
2.2797(10); Ru-H(1), 1.70(3); Ru-H(2), 1.71(3); Ru-H(3), 1.60(4);
Ru-H(4), 1.54(4); H(1)-H(2), 0.87(3). Selected bond angles (deg):
P(1)-Ru-P(2), 154.39(3); P(1)-Ru-P(3), 96.08(4); P(2)-Ru-P(3),
103.16(4); P(3)-Ru-H(4), 172.0(15); H(3)-Ru-H(1), 163(2); H(2)-
Ru-H(3), 167.7(19).
Results and Discussion
Synthesis and Spectroscopic Properties of [RuH2(η2-H2)-
(PCy3)2(2-phenyl-3,4-dimethylphosphaferrocene)] (2). The
complex [RuH2(η2-H2)(PCy3)2(L1)] (2) is readily prepared by
stirring an equimolar, heterogeneous mixture of RuH2(H2)2-
(PCy3)2 (1) and 2-phenyl-3,4-dimethylphosphaferrocene (L1) in
pentane at -20 °C (see Scheme 1). After the evolution of
dihydrogen has ceased, filtration of the subsequent orange
solution and cooling overnight affords 2·2C5H12 as small, orange
cubes suitable for single-crystal X-ray diffraction. Microcrys-
talline samples of 2 can be isolated free of cocrystallized solvent
by drying in a stream of argon. Complex 2 is very air sensitive
and unusually unstable in the solid state, in the presence or in
the absence of a dihydrogen atmosphere, yielding an intractable
black solid.
Table 1. Crystallographic Data for 2
formula
fw
C53H87FeP3Ru (0.75 pentane)
1030.66
space group
a, Å
b, Å
c, Å
P21/c
12.2591(14)
13.7902(13)
34.848(4)
94.636(14)
4; 1.1666
140(2)
5872.0(11)
0.710 73
0.618
â, deg
Z; calcd density, mg/m3
temp, K
1
V, Å3
The H NMR spectrum (400 MHz) of 2 in toluene-d8 at
λ, Å
ambient temperature shows, as expected, a broad signal, with a
half peak-height line width of 109 Hz, at -8.15 ppm consistent
with the fast exchange of all the metal-bound hydrogen atoms.
Other pertinent features include the nonequivalent methyl
resonances (2.37 and 2.48 ppm), indicative of the planar chirality
in the monophosphaferrocene precursor, a doublet (3.52 ppm)
for the lone proton within the same π-ligand which has a reduced
coupling constant (2JP-H ) 31 Hz), and a sharp singlet at 4.25
ppm for the unsubstituted iron-bound cyclopentadienyl ligand.
However, most noteworthy is the retention of both ortho phenyl
protons in 2 which shows the reluctance of the monophospha-
µ, mm-1
R1 [I > 2σ(I)]
wR2
0.0439
0.1136
ferrocene to undergo an orthometalation reaction at room
temperature (vide infra). Integration, with a repetition time delay
of 30 s, of all the observed resonances, is consistent with the
proposed structure for 2. The 31P{1H} NMR spectrum of 2 at
room temperature shows a triplet at 33.61 ppm (2JP-P ) 25
Hz) and a broad signal at 75.53 ppm.
The molecular structure of 2, depicted in Figure 1, confirms
the displacement of one dihydrogen ligand from 1 by the
phosphaferrocene ligand acting as a two electron donor ligand.
Crystal data are reported in Table 1. The structure is ap-
proximately octahedral with two trans tricyclohexylphosphines
(the P1-Ru-P2 angle is 154.39(3)°) bent away from the
phosphaferrocene ligand to reduce steric repulsion (the P3-
Ru-P1 and P3-Ru-P2 angles are 96.08(4) and 103.16(4)°,
respectively). The Ru-H bond lengths vary from 1.54(4) to
1.71(3) Å, and the dihydrogen ligand is characterized by a H1-
H2 distance of 0.87 (3) Å. The phosphaferrocene coordination
to the ruthenium is characterized by a Ru-P(3) distance of
2.2797(10) Å, slightly shorter than the Ru-P1 and Ru-P2
values (2.3271(10) and 2.3281(10) Å, respectively) and an angle
Ru-P3-Ct of 160.2° (Ct for P-C1-C2-C3-C4 centroid)
reflecting the strong s character of the phosphorus lone pair.
Dynamic Behavior of 2. Complex 2 is fluxional on the NMR
(7) (a) Deschamps, B.; Ricard, L.; Mathey, F. J. Organomet. Chem. 1997,
548, 17. (b) Sava, X.; Me´zailles, N.; Maigrot, N.; Ricard, L.; Nief,
F.; Mathey, F.; Le Floch, P. Organometallics 1999, 18, 4205. (c) Sava,
X.; Ricard, L.; Mathey, F.; Le Floch, P. Organometallics 2000, 19,
4899. (d) Ganter, C.; Brassat, L.; Glinsbo¨ckel, C.; Ganter, B.
Organometallics 1997, 16, 2862. (e) Ganter, C.; Brassat, L.; Ganter,
B. Chem. Ber./Recl. 1997, 130, 1771. (f) Ganter, C.; Brassat, L. Ganter,
B. Tetrahedron: Asymmetry 1997, 8, 2607. (g) Ganter, C.; Glinsb-
o¨ckel, C.; Ganter, B. Eur. J. Inorg. Chem. 1998, 1163. (h) Garrett, C.
E.; Fu, G. C. J. Org. Chem. 1997, 62, 4534. (i) Ganter, C.; Kaulen,
C.; Englert, U. Organometallics 1999, 18, 5444. (j) Pala, C.; Podewils,
F.; Salzer, A.; Englert, U.; Ganter, C. Tetrahedron 2000, 56, 17. (k)
Brassat, L.; Ganter, B.; Ganter, C. Chemistry 1998, 4, 2148. (l) Qiao,
S.; Fu, G. C. J. Org. Chem. 1998, 63, 4168. (m) Qiao, S.; Hoic, D.
A.; Fu, G. C. Organometallics 1998, 17, 773. (n) Tanaka, K.; Qiao,
S.; Tobisu, M.; Lo, M. M.-C.; Fu. G. J. Am. Chem. Soc. 2000, 122,
9870.
(8) Sava, X.; Me´zailles, N.; Ricard, L.; Mathey, F.; Le Floch, P.
Organometallics 1999, 18, 807.
(9) (a) Sabo-Etienne, S.; Chaudret, B. Coord. Chem. ReV. 1998, 178-
180, 381 and references therein. (b) Delpech, F.; Sabo-Etienne, S.;
Daran, J.-C.; Chaudret, B.; Hussein, K.; Marsden, C. J.; Barthelat,
J.-C. J. Am. Chem. Soc. 1999, 121, 6668. (c) Atheaux, I.; Donnadieu,
B.; Rodriguez, V.; Sabo-Etienne, S.; Chaudret, B.; Hussein, K.;
Barthelat, J.-C. J. Am. Chem. Soc. 2000, 122, 5664.
1
time scale. The process can be followed by H and 31P NMR
1
spectroscopies. The variable-temperature, high-field H NMR
spectra (400 MHz) obtained on cooling a sample of 2 in toluene-
d8 are shown in Figure 2. At 293 K, a single broad resonance

3036 Inorganic Chemistry, Vol. 40, No. 13, 2001
Toner et al.
Scheme 2
Figure 2. 1H NMR spectra (400.13 MHz) of 2 in C7D8 at various
temperatures.
ppm. A coalescence occurs at 263 K, and at 243 K, the triplet
remains unchanged whereas the broad signal is resolved into a
broad AB spectrum. The activation energy for this process is
∆Gq ) 46.7 kJ/mol at 263 K, thus identical to the value found
1
by H NMR for the exchange between the hydrides and the
dihydrogen ligand. Finally at 213 K, the signal at 34.4 becomes
broad and the AB spectrum is now well defined by two doublets
of doublets (δ(PA) ) 77.7 ppm, δ(PB) ) 70.0, 2JA-B ) 215 Hz
2
2
and JA-C ) JB-C ) 24 Hz). The values of the coupling
constants are in agreement with a trans position for the two
PCy3 groups and a cis position for the phosphaferrocene ligand.
It can be noted that the line width decreases for the two PCy3
whereas it increases for the phosphaferrocene ligand when the
temperature is lowered. This behavior can be explained either
by different τc’s resulting in different T2’s or to two slightly
different exchange processes occurring between PC and PA and
PC and PB.
Exchange between hydrides and dihydrogen ligands is
commonly observed in dihydrogen complexes, but there are only
a few precedents in the literature in which decoalescence has
been observed by 1H NMR at low temperature. This is the case
10
for the carbonyl complex RuH2(H2)(CO)(PiPr3)2 and for
RuH2(H2)(PhP[CH2CH2CH2P(Cy2)]2)11 with a chelating triph-
osphine whereas decoalescence has never been reached in the
cases of RuH2(H2)(PR3)3 with R ) Ph or Cy.12
Reactivity Studies on 2. 2 is indefinitely stable in solution
at 10-2 Torr (flame-sealed NMR tube) and shows no propensity
to decompose at higher temperatures in solution (vide infra).
However, solid 2 decomposes readily at -20 °C (ca. 1 d) even
under an atmosphere of dihydrogen (3 bar). 2 was found to be
remarkably stable when a C7D8 solution, in a sealed NMR tube,
was heated from 40 to 80 °C for 6 h. No decomposition was
noted, but H-D exchange occurred leading to the observation
of the HD isotopomer RuH2(HD)(PCy3)2(L1) as evidenced by
1H and 31P NMR studies at 293 and 213 K (see Scheme 2). At
213 K the pseudoquintet at -9.95 ppm remains unchanged
whereas the broad signal observed at -5.95 ppm (with no
isotopic shift) is now resolved into a broad triplet which
Figure 3. 31P{1H} NMR spectra (161.98 MHz) of 2 in C7D8 at various
temperatures (asterisk ) impurity).
is observed at -8.15 ppm assigned to the four hydrogen atoms
in fast exchange. Coalescence is observed at 263 K leading to
two broad signals at -6 and -10 ppm of equal intensity. The
latter signal appears as a pseudoquintet at 213 K. The exchange
between the dihydrogen ligand and the two hydrides is
characterized by a ∆Gq of 46.2 kJ/mol at 263 K. T1 measure-
ments were performed using the inverse-recovery method. The
minimum is observed at 263 K (37 ms), and as the temperature
is decreased further, the T1 values for the two signals increase
but much faster for the signal at -10 ppm. The variable-
temperature, 31P{1H} NMR spectra obtained on cooling a sample
of 2 in toluene-d8 are shown in Figure 3. The spectrum shows
at 293 K a triplet at 33.61 ppm (2JP-P ) 24 Hz) assigned to the
phosphorus (PC) of the phosphaferrocene ligand coupled to the
two PCy3 (PA and PB) which resonate as a broad signal at 75.53
2
transforms into a singlet upon H decoupling. The two signals
(10) Gusev, D. G.; Vymenits, A. B.; Bakhmutov, V. I. Inorg. Chem. 1992,
31, 2.
(11) Jia, G.; Meek, D. W. J. Am. Chem. Soc. 1989, 111, 757.
(12) (a) Crabtree, R. H.; Hamilton, D. G. J. Am. Chem. Soc. 1986, 108,
3124. (b) Arliguie, T.; Chaudret, B.; Morris, R. H.; Sella, A. Inorg.
Chem. 1988, 27, 598.

Ruthenium(II) Monophosphaferrocene Complexes
Inorganic Chemistry, Vol. 40, No. 13, 2001 3037
integrate in a ratio 2:1, and the coupling constant JH-D value is
30 Hz, in agreement with the formation of an HD isotopomer.
Estimation of the dHH distance from this value using the equation
developed by Morris leads to 0.92 Å, in good agreement with
the X-ray data.13
the catalytic properties of this new family of ruthenium
complexes will be developed.
Experimental Section
General Considerations. Inert-atmosphere glovebox and Schlenk-
line techniques were used throughout the preparative procedures unless
otherwise indicated. The following solvents were refluxed over the
appropriate drying agent and subsequently distilled under an atmosphere
of dinitrogen or argon. Toluene was distilled from sodium; diethyl ether
and tetrahydrofuran were distilled from purple sodium/benzophenone.
Dichloromethane and pentane were refluxed over, and distilled from,
calcium hydride. All deuterated solvents (toluene-d8, benzene-d6,
tetrahydrofuran-d8, and dichloromethane-d2) were prestored over oven-
dried molecular sieves and then thoroughly degassed during four freeze,
degass, and thaw cycles. All NMR samples were prepared in either
flame-sealed (ca. 10-2 Torr) or Teflon-stoppered NMR tubes unless
Substitution of the dihydrogen ligand in 2 was readily
achieved with ethylene or CO (see Scheme 2). Thus, bubbling
ethylene into a C6D6 solution of 2 leads to a total conversion
into a new complex RuH2(C2H4)(PCy3)2(L1) (3) resulting from
the substitution of the dihydrogen ligand by ethylene. However,
further attempts should be performed (in particular at low
temperature) in order to isolate the complex, as decomposition
was rapidly observed, leading to a mixture of unidentified
complexes in addition to free phosphines. The spectroscopic
data are given in the Experimental Section. The analogous
carbonyl complex RuH2(CO)(PCy3)2(L1) (4) was similarly
characterized. In this case, bubbling CO into a C6D6 solution
of 2 leads to partial conversion into 4 with concomitant
formation of the known dicarbonyl complex RuH2(CO)2-
(PCy3)214 and free 2-phenyl-3,4-dimethylphosphaferrocene (L1).
3 and 4 have very similar spectroscopic data.
1
otherwise stated. H (200.13, 250.13, 300.13, or 400.13 MHz), 13C
(62.90, 75.47, or 100.61 MHz), and 31P NMR (81.01, 121.49, or 161.98
MHz) spectra were recorded on Bruker instruments. Chemical shifts
(δ) for 1H NMR spectra are reported relative to the residual protons in
the deuterated solvents and for 13C NMR spectra relative to the carbons
in the deuterated solvent. 31P NMR spectra are reported relative to
phosphoric acid (δ ) 0.0 ppm) as the external standard. ∆Gq values
were obtained from 1H and 31P NMR data. They were calculated using
the coalescence temperatures and frequency differences between the
coalescing signals in the limit of slow exchange.15
Synthesis of [RuH2(PCy3)2(3,4-dimethylphosphaferrocene)2]
(5). The preparation of 5 was achieved by reaction of 1 with a
2-fold equivalent of 3,4-dimethylphosphaferrocene (L2), in cold
pentane (-20 °C). Stirring was continued for ca. 45 min to yield
a deep orange solution. Following filtration and removal of the
solvent in vacuo, 5 was obtained in 64% yield as an orange
microcrystalline solid (see Scheme 1). An equimolar ratio of 1
and L2 under identical conditions affords 5 and the recovery of
1 (ca. 40%). The 31P{1H} NMR spectrum of 5 shows two triplets
at 9.64 and 67.53 ppm with a small JP-P coupling constant (2JP-P
) 25 Hz) consistent with two types of phosphines in a cis
disposition. The 1H NMR spectrum shows a doublet of triplets
Preparation of [RuH2(η2-H2)(PCy3)2(2-phenyl-3,4-dimethylphos-
phaferrocene)] (2). Pentane (ca. 20 mL) was added, with stirring, to
a Schlenk containing RuH2(H2)2(PCy3)2 (1) (430 mg, 0.65 mmol) and
2-phenyl-3,4-dimethylphosphaferrocene (L1) (200 mg, 0.65 mmol)
cooled to -20 °C. The mixture was subsequently stirred until the
starting materials had been consumed and dihydrogen evolution had
ceased to afford a deep orange solution. After filtration and refrigeration,
orange crystals of [RuH2(η2-H2)(PCy3)2(L1)]·2C5H12 suitable for single-
crystal X-ray diffraction analysis were collected by decantation of the
mother liquor. A further crop of unsolvated, analytically pure, micro-
crystalline material was collected by cooling the filtrate. Yield: 568
mg, 90%. Anal. Calcd for 2, RuFeP3C53H87: C, 65.36; H, 8.94.
for the hydrides centered at -9.69 ppm (2JP
) 26 Hz,
cis-H
2JP
) 89 Hz) which simplifies to a triplet upon selective
trans-H
decoupling of the 31P signal at 9.64 ppm and to a doublet upon
selective decoupling of the 31P signal at 67.53 ppm. The
resonance of the CH protons R-bound to the phosphorus of the
phosphaferrocene ligands appears as a doublet at 3.19 ppm
(2JP-H ) 30.7 Hz) which transforms into a singlet upon selective
decoupling of the 31P signal at 9.64 ppm. This allows the
attribution of the signal at 9.64 ppm to the resonance of the
phosphaferrocene ligands.
1
Found: C, 64.90; H, 8.79. H NMR at 400.13 MHz in toluene-d8: at
293 K, -8.15 (br, RuH4, 4H), 1.1-2.5 (m, 66H, P(C6H11)3), 2.37 (s,
2
3H, CH3), 2.48 (s, 3H, CH3), 3.52 (d, 1H, C4HPMe2, JP-H 31 Hz),
3
4.25 (s, 5H, C5H5), 7.31 (t, Hp, 1H, JH-H 7.4 Hz), 7.48 (t, Hm, 2H,
3JH-H 7.6 Hz), 7.80 (d, Ho, 2H, 3JH-H 7.6 Hz); at 213 K (selected data),
2
-5.90 (br, Ru(η2-H2), 2H), -9.95 (pq, RuH2, 2H, JP(AB)-H 21 Hz,
2JP(C)-H 42 Hz). 31P{1H} NMR at 161.98 MHz in toluene-d8: at 293
K, 33.61 (t, 2JP-P 24 Hz, PC), 75.53 (br, PA, PB); at 213 K, 34.64 (br),
In summary, it is amazing to note that, despite the bulkiness
of the tricyclohexylphosphine, the ruthenium can still accom-
modate in its coordination sphere one or two presumed bulky
phosphaferrocene ligands leading to the formation of 2 and 5.
Complex 2 is a rare example of a dihydride dihydrogen complex
in which decoalescence between the classical hydrides and the
dihydrogen ligand can be observed by NMR. X-ray data and a
deuteration experiment are in favor of an unstretched dihydrogen
ligand. Thus, this dihydrogen ligand is labile as illustrated by
the preliminary reactivity studies we have performed on 2. Our
primary goal to induce orthometalation by using a ligand such
as L1 was not achieved; however, we have opened access to a
wide variety of ruthenium complexes accommodating phos-
phaferrocene ligands and other phosphines. Investigations of
2
2
2
77.7 and 70.0 (AB type, JP(A)-P(C) ) JP(B)-P(C) 24 Hz, JP(A)-P(B) 215
Hz). 13C{1H}{JMOD} NMR at 100.61 MHz in toluene-d8 at 293 K:
16.47 (s, C4HPMe2), 17.33 (d, C4HPMe2, JC-P 3.2 Hz), 27.83 (s,
3
P(C6H11)3), 28.80 (vt, P(C6H11)3, JC-P 4.5 Hz), 28.89 (vt, P(C6H11)3,
J
C-P 4.5 Hz), 30.57 (s, P(C6H11)3), 31.07 (s, P(C6H11)3), 39.52 (br, CR,
1
P(C6H11)3), 72.47 (d, CR, C4HPMe2, JC-P 9.8 Hz), 74.57 (s, C5H5),
86.64 (d, Câ, C4HPMe2, 2JC-P 2.5 Hz), 90.03 (d, arylated CR, C4HPMe2,
1JC-P 15.3 Hz), 91.59 (d, Câ, C4HPMe2, JC-P 2.5 Hz), 127.75 (s, Cm,
C6H5), 129.48 (s, Cp, C6H5), 131.75 (d, Cortho, C6H5, JC-P 5.1 Hz),
141.57 (d, Cipso, C6H5, JC-P 14.9 Hz).
2
3
2
X-ray Analysis of 2. Data collection were collected at low
temperature (T ) 140 K) on a Stoe imaging plate diffraction system
(IPDS), equipped with an Oxford Cryosystems Cryostream cooler
device and using graphite-monochromated Mo KR radiation (λ )
0.710 73 Å). The final unit cell parameters were obtained by least-
squares refinement of a set of 5000 well-measured reflections, and
crystal decay was monitored by measuring 200 reflections by image.
No significant fluctuation of the intensity was observed over the course
(13) (a) Maltby, P. A.; Schlaf, M.; Steinbeck, M.; Lough, A. J.; Morris, R.
H.; Klooster, W. T.; Koetzle, T. F.; Srivastava, R. C.J. Am. Chem.
Soc. 1996, 118, 5396. (b) Gru¨ndemann, S.; Limbach, H.-H.; Bunt-
kowsky, G.; Sabo-Etienne, S.; Chaudret, B. J. Phys. Chem. A 1999,
103, 4752.
(14) Christ, M. L.; Sabo-Etienne, S.; Chaudret, B. Organometallics 1994,
13, 3800.
(15) Friebolin, H. Basic one- and two-dimensional NMR spectroscopy, 2nd
ed.; VCH: Weinheim, Germany, 1993; pp 293-295.

3038 Inorganic Chemistry, Vol. 40, No. 13, 2001
Toner et al.
of the data collection. Numerical absorption corrections16 were applied
on the data. The structure was solved by direct methods using SIR9217
and refined by least-squares procedures on a F2 with the aid of
SHELXL97 by minimizing the function Σw(Fo2 - Fc2)2, where Fo and
Fc are respectively the observed and calculated structure factors.18 The
atomic scattering factors were taken from ref 19. All hydrogen atoms
were located on a difference Fourier maps and refined in a riding model,
except for the hydrides H(1), H(2) and hydrogen atoms H(3), H(4) of
the dihydrogen ligand; their positions have been refined using restraints
and isotropic thermal parameters of hydrides and the hydrogens atoms
of H2 ligand have been set to be equivalent, respectively. All remaining
non-hydrogen atoms were anisotropically refined, and in the last cycles
of refinement a weighting scheme was applied, where weights have
Reaction of 2 with CO. An NMR tube containing a benzene-d6
solution (ca. 0.7 mL) of [RuH2(η2-H2)(PCy3)2(L1)] (20 mg, 0.02 mmol)
was treated with a slow stream of carbon monoxide for ca. 5 min during
which time the orange solution gradually darkened in color. The reaction
was subsequently conducted on a 100 mg scale, but all attempts to
separate [RuH2(CO)(PCy3)2(L1)] (4) from 2-phenyl-3,4-dimethylphos-
phaferrocene (L1) and [RuH2(CO)2(PCy3)2] by column chromatography
(aluminum oxide 90, Merck) failed.
Data for 4. 1H NMR at 200.13 MHz in benzene-d6 at 293 K: -8.53
(pqd, RuH, 1H, JH-H 6 Hz, JH-P ) 25 Hz), -9.35 (dtd, RuH, 1H, JH-H
6 Hz, JH-PA ) JH-PB ) 27 Hz, JH-PX ) 114 Hz), 1.0-2.3 (broad
multiplets, P(C6H11)3), 2.06 (s, CH3), 2.18 (s, CH3), 3.40 (d, 1H,
2
C4HPMe2, JP-H 30 Hz), 4.08 (s, 5H, C5H5), 7.10 (t, Hpara, partially
3
been calculated from the following formula: w ) 1/[σ2(Fo ) + (aP)2
2
hidden by solvent peak), 7.30 (t, Hmeta, 2H, JH-H 7.8 Hz), 7.64 (d,
3
H
ortho, 2H, JH-H 7.3 Hz). 31P{1H} NMR at 81.01 MHz in benzene-d6
2
+ bP], where P ) (Fo + 2Fc2)/3. Drawing of the molecule was
at 293 K: ABX type, 67.7 and 62.8 (mbr, 2 PCy3, PA and PB, JPA-PB
206 Hz), 14.5 (br, PX).
performed with the program ZORTEP with 50% probability displace-
ment ellipsoids for non-hydrogen atoms.20
Preparation of [RuH2(PCy3)2(3,4-dimethylphosphaferrocene)2]
(5). Pentane (ca. 20 mL) was added, with stirring, to a Schlenk tube
charged with [RuH2(η2-H2)2(PCy3)2] (860 mg, 1.29 mmol) and 3,4-
dimethylphosphaferrocene (L2) (598 mg, 2.58 mmol) at -20 °C. Stirring
was continued for ca. 45 min to yield a deep orange solution. After
filtration, to remove a little insoluble material, the solvent was removed
in vacuo to yield crude [RuH2(PCy3)2(L2)2] (930 mg, 64%) as a bright
orange, microcrystalline solid. Recrystallization from pentane at ca.
-20 °C gave an analytically pure sample containing cocrystallized
solvent. Anal. Calcd for 5·C5H12, RuFe2P4C63H106: C, 63.05; H, 8.84.
Reaction of 2 with Ethylene. An NMR tube containing an orange,
benzene-d6 (ca. 0.7 mL) solution of 2 (20 mg, 0.02 mmol) was treated
with a slow stream of ethylene for ca. 10 min at room temperature
during which time there were no obervable color changes. Only one
complex was observed and characterized as [RuH2(C2H4)(PCy3)2(L1)]
1
(3). H NMR at 200.13 MHz in benzene-d6 at 293 K: -9.88 (pqd,
RuH, 1H, JH-H 7.3 Hz, JH-P ) 26 Hz), -11.65 (dtd, RuH, 1H, JH-H
7.3 Hz, JH-PA ) JH-PB ) 27 Hz, JH-PX ) 126 Hz), 1.07-2.30 (broad
multiplets, P(C6H11)3 and C2H4), 2.07 (s, 3H, CH3), 2.13 (s, 3H, CH3),
2
2.53 (br, 2H, C2H4), 3.25 (d, 1H, C4HPMe2, JP-H 30.52 Hz), 4.10 (s,
1
Found: C, 63.26; H, 8.92. H NMR at 300.13 MHz in toluene-d8 at
5H, C5H5), 7.16 (t, Hpara, partially hidden by solvent peak), 7.26 (t,
2
2
293 K: -9.69 (dt, RuH2, 2H, JP
26 Hz, JP
89 Hz), 1.31-
-H
trans
-H
cis
H
meta, 2H, 3JH-H 7.85 Hz), 7.54 (d, Hortho, 2H, 3JH-H 7.32 Hz). 31P{1H}
2.22 (broad multiplets, P(C6H11)3), 2.07 (s, 12H, CH3), 3.19 (d, 4H,
C4H2PMe2, 2JP-H 30.7 Hz), 4.09 (s, 10H, C5H5). 31P{1H} NMR at 121.94
MHz in toluene-d8 at 293 K: 9.64 (t), 67.53 (t), (2JP-P 25 Hz). 13C-
{1H} NMR at 75.47 MHz in toluene-d8 at 293 K: 16.50 (s, C4H2PMe2),
27.57 (s, P(C6H11)3), 28.60 (vt, P(C6H11)3, JC-P 4.60 Hz), 31.38 (s,
P(C6H11)3), 38.01 (br, vt, P(C6H11)3, JC-P 9.7 Hz), 72.59 (s, C5H5), 73.27
NMR at 81.01 MHz in benzene-d6 at 293 K: ABX type, 65.1 and
62.7 (ddd, 2 PCy3, PA and PB, JPA-PB 189 Hz, JPA,B-PX 21 Hz), 11.6
(br, PX).
(16) X-SHAPE (revision 1.01), July 1996. A Crystal Optimisation for
Numerical Correction STOE and Cie. (X-SHAPE is based on the
program “HABITUS” by Dr. Wolfang Herrendorf, Institu¨t fu¨r Anor-
ganische Chemie, Universitaˆt Giessen.)
(17) Altomare, A.; Cascarano, G.; Giacovazzo, G.; Guagliardi, A.; Burla,
M. C.; Polidori, G.; Camalli, M. J. Appl. Crystallogr. 1994, 27, 435.
(18) Sheldrick, G. M. SHELXL97. Program for the refinement of Crystal
Structures; University of Go¨ttingen: Go¨ttingen, Germany, 1997.
(19) International tables for X-ray crystallography; Kynoch press, Bir-
mingham, England, 1974; Vol. IV.
1
(d, CR of C4H2PMe2, JP-C 7.8 Hz), 89.96 (s, Câ of C4H2PMe2).
Acknowledgment. A.J.T., B.D., S.S.-E, and B.C. thank the
CNRS and EC through the HCM program, Hydrogen Location
and Transfer network.
Supporting Information Available: An X-ray crystallographic file
in CIF format. This material is available free of charge via the Internet
at http://pubs.acs.org.
(20) Zolna¨ı, L. ZORTEP, Graphical Program for X-ray Structures Analysis;
University of Heildelberg: Heildelberg, Germany, 1998.
IC001404V