Bimetallic complexes with ruthenium and tantalocene moieties: Synthesis and use in a catalytic cyclopropanation reaction

Article abstract of DOI:10.1016/j.jorganchem.2006.03.029

The reaction of the tantalocene dichloride monophosphines (1-2) with the binuclear complex [(p-cymene)RuCl₂]₂ gives the heterobimetallic compounds (p-cymene)[(η⁵-C₅H₅)(μ-η⁵:η¹-C₅H₄(CH₂)₂PR₂)TaCl₂]RuCl₂ (3-4). The air oxidation of these bimetallic species 3-4, leads to the cationic hydroxo tantalum ruthenium derivatives 5-6. The last ones are easily deprotonated by a base to afford the oxo analogues 7-8. A preliminary assessment in catalytic cyclopropanation of styrene with tantalum ruthenium bimetallic complexes 3-8 as precatalysts revealed a cooperative effect with a subtle role of the early metal fragment.

Full text of DOI:10.1016/j.jorganchem.2006.03.029

Journal of Organometallic Chemistry 691 (2006) 3239–3244
www.elsevier.com/locate/jorganchem
Bimetallic complexes with ruthenium and tantalocene
moieties: Synthesis and use in a catalytic cyclopropanation reaction
*
*
´ ˆ
Jerome Goux, Pierre Le Gendre , Philippe Richard, Claude Mo¨ıse
` `
´ ´ ´
Laboratoire de Synthese et Electrosynthese Organometalliques, LSEO-UMR 5188, Universite de Bourgogne, Faculte des Sciences Mirande,
9 avenue Alain Savary, 21000 Dijon, France
Received 21 December 2005; received in revised form 16 March 2006; accepted 16 March 2006
Available online 24 March 2006
Abstract
The reaction of the tantalocene dichloride monophosphines (1–2) with the binuclear complex [(p-cymene)RuCl2]2 gives the heterobi-
metallic compounds (p-cymene)[(g5-C5H5)(l-g5:g1-C5H4(CH2)2PR2)TaCl2]RuCl2 (3–4). The air oxidation of these bimetallic species 3–
4, leads to the cationic hydroxo tantalum ruthenium derivatives 5–6. The last ones are easily deprotonated by a base to afford the oxo
analogues 7–8. A preliminary assessment in catalytic cyclopropanation of styrene with tantalum ruthenium bimetallic complexes 3–8 as
precatalysts revealed a cooperative effect with a subtle role of the early metal fragment.
ꢀ 2006 Elsevier B.V. All rights reserved.
Keywords: Tantalum; Ruthenium; Heterobimetallic complexes; Cyclopropanation
1. Introduction
screening of their catalytic behavior and they have already
proved to be efficient precatalysts in ring closing metathe-
sis, in enol esters synthesis and in cyclopropanation [5].
These results prompt us to extend this family of heterobi-
metallic catalysts by replacing the titanium atom in the
‘‘early’’ fragment with a less oxophilic metal such as tanta-
lum. Herein, we report the synthesis and the characteriza-
tion of a series of new tantalum ruthenium bimetallic
complexes. Work was then focused on cyclopropanation
as a representative reaction in order to compare the activity
of the bimetallic complexes 3–8 with the monometallic spe-
cies (p-cymene)RuCl2PR3.
The preparation and the study of ‘‘early–late’’ heterobi-
metallic complexes is a particularly active research area in
organometallic chemistry [1]. Part of the increasing interest
in this investigation is the hope that these species might
exhibit unusual catalytic activity due to a cooperative reac-
tivity between the electron-deficient and the electron-rich
metals [2]. Convinced that a marked cooperative effect
may occur rather with a joined binuclear catalysts than
with a mixture of their dissociated monometallic ana-
logues, we designed our complexes around cyclopentadie-
nylphosphine ligands able to strongly bind both ‘‘early’’
and ‘‘late’’ fragments and to maintain them in a close prox-
imity [3]. Previous studies in our laboratory using this lin-
ker gave rise to a straightforward access to several titanium
ruthenium and titanium rhodium complexes [4]. These last
ones have been obtained in sufficient amount to carry out a
2. Results and discussion
Our strategy to construct the bimetallic complexes con-
sists first in synthesizing the tantalocene dichloride phos-
phine compounds and then coordinating these early
metal ligands to the late metal fragment. One aspect of
interest of this approach is the structural flexibility of the
tantalocene phosphine. Indeed the basicity and the crowd-
ing of the phosphine can be modulated by appropriate
*
Corresponding authors. Tel.: +3 33 8039 6082; fax: +3 33 8039 6098.
E-mail addresses: pierre.le-gendre@u-bourgogne.fr (P.L. Gendre),
claude.moise@u-bourgogne.fr (C. Mo¨ıse).
0022-328X/$ - see front matter ꢀ 2006 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2006.03.029

3240
J. Goux et al. / Journal of Organometallic Chemistry 691 (2006) 3239–3244
substitution. Moreover, the introduction of an alkyl spacer
between the cyclopentadienyl ring and the phosphino
group might prevent steric constraints on the complex
and will allow greater conformational freedom of the two
metal coordination spheres. Accordingly, we have decided
to use (phosphinoethyl)cyclopentadienyl ligands, one with
a diphenylphosphino group and another with a bulkier
and more basic dicyclohexylphosphino moiety. The syn-
spectra still exhibit the eight-line characteristic of tantalum
(IV) dichloride derivatives.
Recently, we have described a new route to cationic
hydroxo tantalum (V) species by air oxidation of tantalo-
cene dichloride complexes. The hydroxo complexes can
be easily deprotonated to generate the corresponding oxo
derivatives [9]. In the aim to expand substantially the num-
ber of Ta–Ru bimetallic complexes, we studied the air oxi-
dation of the Ta–Ru heterobimetallic species 3 and 4. A
THF solution of 3 and 4 was exposed to air for 12 h afford-
ing a red precipitate identified as the hydroxo bimetallic
complexes 5 and 6 (Scheme 3). The 31P NMR spectra of
5 and 6 exhibit singlets at d = 23.8 and d = 27.9 ppm which
confirms that the phosphorus atom remains coordinated in
thesis of the metallophosphines
1 and 2
Cp*[g5-
C5H4(CH2)2PR2]TaCl2 is adapted to Bercaw’s method as
outline in Scheme 1 [6]. The starting material Cp*TaCl4 is
reduced by magnesium in the presence of trimethylphos-
phine to afford the red intermediary Cp*TaCl3PMe3 which
reacts with [C5H4(CH2)2PR2]Li to lead to the desired prod-
ucts 1 and 2. Complexes 1 and 2 have been isolated in good
yields as green solids. They display the eight-line ESR spec-
tra characteristic of bis(cyclopentadienyl)tantalum (IV)
derivatives [7]. Although 1 and 2 are paramagnetic prod-
ucts, their 31P NMR spectra in C6D6 show slightly broad-
ened singlets at d = À17.4 ppm for 1 and at d = À6.0 ppm
for 2 as expected for free metallophosphines.
Organic phosphines can easily cleave the chloride
bridges of the binuclear complex [(p-cymene)RuCl2]2 to
lead to (p-cymene)RuCl2PR3 complexes [8]. On the basis
of this result, we carried out experiments by using the
metallophosphines 1 and 2 with the ruthenium binuclear
complex [(p-cymene)RuCl2]2 in dichloromethane. The
desired heterobimetallic complexes 3 and 4 were obtained
in good yields after 4 h at room temperature (Scheme 2).
The characterization of 3 and 4 are based upon elemental
analysis, ESR and 31P NMR spectroscopic data. The 31P
NMR chemical shifts of 3 and 4 at d = 21.4 and
d = 22.1 ppm correspond to a downfield shift of 38.8 and
28.1 ppm, respectively, to free metalloligands (1 and 2).
These results are indicative of the coordination of the phos-
phorus atoms to the ruthenium metal. Moreover, ESR
1
both cases to the ruthenium metal. The H NMR spectra
show all the signals attempted for both metallic fragments.
The cyclopentadienyl ring protons appear as four signals,
which confirmed the loss of symmetry expected by the sub-
stitution of one chloride atom by a hydroxyl group on the
tantalum atom. Moreover, the strong deshielding of these
signals (from d = 5.53 to 7.00 ppm) is in agreement with
a cationic tantalum (V) species. IR spectra exhibit a broad
and strong peak from 2100 to 2900 cmÀ1 corresponding to
the OH stretching band which is in accordance with our
previous study [9].
Finally, 6 has been partially characterized using single-
crystal X-ray diffraction, although because of extensive dis-
order of the solvate molecule(s), only a partial structure
refinement was possible. The electron difference density
map was not sufficiently clear to successfully model a badly
disordered solvent molecule and so the BYPASS procedure
implemented in the PLATON program [10] was used to han-
dle this problem. In this procedure the contribution of the
solvent electron density is substracted to the structure fac-
tors. Despite the poor quality of the data, the experiment
does, however, confirm the basic connectivity around the
PR2
2
[C5H4(CH2)2PR2]Li
toluene, 100˚C
Mg
Cl
Cl
Ta
Ta
Ta
PMe3
Cl
Cl
Me3P
Cl
Cl
Cl
Cl
Cl
1 : R = Ph
2 : R = Cy
Scheme 1.
Ru
PR2
P
R2
2
2
Cl
Cl
1/2 [(p-cymene)RuCl2]2
benzene, r.t., 4h
Cl
Cl
Cl
Cl
Ta
Ta
1 : R = Ph
2 : R = Cy
3
4
Scheme 2.

J. Goux et al. / Journal of Organometallic Chemistry 691 (2006) 3239–3244
3241
+
Cl-
Ru
Cl
Ru
Cl
Ru
Cl
P
R2
P
R2
P
R2
2
2
2
Cl
Cl
Cl
air
NEt3
Cl
Cl
O
Cl
Cl
Ta
Ta
Ta
THF
toluene
OH
3 : R = Ph
4 : R = Cy
5
6
7
8
Scheme 3.
metallic center (for information, the final residuals with the
solvent-corrected data are: wR2 = 0.135 for all data,
R1 = 0.050 for 6826 data with I > 2r(I), GOF = 0.94). An
ORTEP view of 6 is shown in Fig. 1. This view shows that
an oxygen atom substitutes a chlorine one on the tantalum
been interested in comparing the catalytic activities of
(p-cymene)RuCl2(PR3) complexes and heterobimetallic
Ta–Ru complexes. Cyclopropanation experiments were
performed using styrene as model substrate and ethyl dia-
zoacetate as carbene precursor. We carried out the reaction
in styrene, during four hours at 60 ꢁC, by using a catalytic
amount of the bimetallic complexes 3–8. For comparative
purposes, the monometallic complexes (p-cymene)Ru-
Cl2(PPh3) and (p-cymene)RuCl2(PCy3) were tested in simi-
lar conditions (see Table 1).
˚
center. The Ta–O bond’s length (1.894(4) A) is in agree-
ment with the values of the literature for a simple bond
[9,11]. Moreover the O–Ta–Cl(1) angle of 98.9(2)ꢁ in the
‘‘early’’ fragment corresponds to the value expected for a
d0 tantalum (V) cationic hydroxo species [9].
Treatment of 5 and 6 with NEt3 in toluene for two hours
gave, after evaporation of the solvent, the oxo bimetallic
species 7 and 8 as red powders (Scheme 3). The H NMR
A comparison of the reactivity patterns between the
mono- and the bimetallic complexes show that all the
complexes catalyze the reaction with a comparable level
of activity. Moreover, the ratio cis/trans are similar
and always in favor of the trans isomer. At first sight,
these results show that the ruthenium moiety is the active
metal center, and that the tantalocene acts as a simple
spectator atom. Looking at these results more in detail,
it appears that the bimetallic complexes are more selec-
tive than the monometallic ones in the way that they
do not catalyze the competitive formation of stilbene.
At this point, it is worth mentioning that the adjunction
of a catalytic amount of Cp*CpTaCl2 to a run performed
with (p-cymene)RuCl2PCy3 has almost no effect on the
selectivity of this reaction. Therefore, it can be assumed
that both metallic fragments should be tethered to exhi-
bit a significant cooperative effect. Finally, the nature of
the ligands on the tantalum atom plays also a role.
Indeed, the bimetallic complexes 4, 6 and 8 with the
same dicyclohexylphosphino group mediate the cyclo-
propanation of styrene with ethyl diazoacetate with com-
parable chemo- and diastereoselectivity but with different
yields, the overall best result being obtained with the cat-
ionic hydroxo tantalum ruthenium complex 6 (61%
yield). To account for the selectivity towards cycloprop-
anation versus metathesis, we presume that this chemose-
lectivity occurs thanks to a multidentate ligand effect
rather than to the bimetallic effect itself. In accordance
with our previous study related to the titanium ruthe-
nium bimetallic complexes in catalytic cyclopropanation,
we propose that the vacant sites on the ruthenium atom,
resulting from the disengagement of the p-cymene, are
partially occupied by a chelate effect of the metalloligand
which prevents the coordination of the styrene and so
inhibits the formation of metathesis by-products.
1
spectra exhibit four signals for the four cyclopentadienyl
ring protons less deshielding than those of 5 and 6 which
results from the loss of the cationic character of the tanta-
lum atom. Finally, the IR spectra show a strong peak
located at 810 cmÀ1 for 7 and 813 cmÀ1 for 8 which corre-
spond to the Ta=O stretching band [9,12].
For more than a decade, the arene-ruthenium type pre-
catalysts have been particularly developed for the olefin’s
cyclopropanation reaction [13,14]. In this context, we have
Cl2
Cl3
Ru
Ct3
P
Cl4
Ct2
Ta
O
Cl1
Ct1
Fig. 1. ORTEP view of the bimetallic complex 6. Hydrogen atoms are
˚
omitted for clarity. Selected bond lengths (A) and angles (ꢁ) for compound
6: Ta–O = 1.894(4). O–Ta–Cl(1) = 98.9(2).

3242
J. Goux et al. / Journal of Organometallic Chemistry 691 (2006) 3239–3244
Table 1
a
Addition of ethyl diazoacetate to styrene catalyzed by the heterobimetallic complexes 3–8 or by the monometallic complexes (p-cymene)RuCl2PR3
H
CO2Et
Ta-Ru cat.
-N2
+
N2CHCO2Et
+
+
Ph
Ph
Ph
Ph
CO2Et
Ph
H
Catalyst
Cyclopropanationa
Yield (%)b
Metathesis
TONb
trans/cisc
(p-cymene)RuCl2(PPh3)
(p-cymene)RuCl2(PCy3)d
TaCl2APPh2 [Ru] 3
TaCl2APCy2 [Ru] 4
Ta+OHAPPh2 [Ru] 5
Ta+OHAPCy2 [Ru] 6
Ta=OAPPh2 [Ru] 7
Ta=OAPCy2 [Ru] 8
a
57
46
44
51
33
61
42
41
62/38
55/45
62/38
61/39
59/41
62/38
62/38
62/38
10
40
0.4
0.8
0.4
0.4
0.4
1.2
Conditions: catalyst (0.01 mmol), olefin (20 mmol), ethyl diazoacetate (1 mmol) diluted with the substrate up to 1 ml, 60 ꢁC, addition time (4 h), overall
reaction time (4.25 h).
b
Determinated by GC using n-decane as internal standard.
Determinated by GC analysis.
Demonceau and Noels have recently obtained a closely similar result [13c].
c
d
3. Conclusion
relative to internal TMS (1H) or external H3PO4 (31P).
ESR spectra have been collected on a Bruker ESP 300 spec-
trometer. Infrared spectra were obtained with a Bruker IFS
66v, Perkin–Elmer 1600 FTIR instrument. The catalytic
cyclopropane synthesis was monitored on a GC-17A SHI-
MADZU with a 007 methyl 5% phenyl silicone capillary
column (30 m). The cyclopentadienyl phosphine ligands
[C5H4(CH2)2PR2]Li [15] and the complexes Cp*TaCl4 [6],
(p-cymene)RuCl2(PR3) [8], were prepared according to
the literature methods.
We report the preparation of six new heterobimetallic
complexes containing both tantalocene and ruthe-
nium(arene) fragments. These synthesis involves first the
preparation of two tantalocene dichloride phosphines fol-
lowed by their coordination to the ruthenium binuclear
complex [(p-cymene)RuCl2]2. Then, the air-oxidation of
the tantalocene dichloride fragment within the bimetallic
complexes affords the corresponding cationic hydroxo tan-
talum ruthenium heterobimetallic complexes. The last one
can be easily deprotonated to form the oxo bimetallic com-
plexes. All these new bimetallic complexes have been tested
in catalytic cyclopropanation of styrene with ethyl diazoac-
etate in comparison with their monometallic ruthenium
analogues ((p-cymene)RuCl2(PPh3) and (p-cymene)RuCl2-
(PCy3)). The results show that the active catalyst is the
ruthenium and that the early metal fragment within these
bimetallic systems prevents any metathesis reaction to turn
over and so focuses the catalytic activity of the late metal
on cyclopropanation. Further studies to rationalize the dif-
ferent catalytic behaviors of the bimetallic complexes are
under progress.
4.1. Complex 1
Compound 1 was synthesized according to Bercaw’s
method reported for Cp*CpTaCl2 [6] with minor modifica-
tions. Cp*TaCl4 (4.58 g, 10 mmol) was reduced with mag-
nesium (0.12 g, 5 mmol) in THF (50 mL) in the presence
of PMe3 (0.76 g, 10 mmol). Removal of the solvent affor-
ded a red residue which was treated with Li[C5H4-
(CH2)2PPh2] (2.94 g, 10 mmol) in toluene (50 mL) at
100 ꢁC. After 12 h of stirring, extraction and crystallization
from CH2Cl2 afforded the green paramagnetic product 1
(green powder, 80% yield). 31P{1H} NMR (202 MHz,
CDCl3) d À17.4 (s, PPh2). The ESR spectrum in toluene
4. Experimental
showed an eight-line spectrum: giso = 1.9293; ATa,iso =
113.98 G. Anal. Calc. for C29H33Cl2PTa (664.44): C,
52.42; H, 5.02. Found: C, 52.60; H, 5.10%.
All the reactions were carried out under an atmosphere
of purified argon. The solvents were dried by the appropri-
ate procedure and distilled under argon immediately before
use. Standard Schlenk techniques and conventional glass
vessels were employed. Elemental analyses were carried
out with a EA 1108 CHNS-O FISONS. 1H (500 MHz)
and 31P{1H} (202 MHz) spectra were collected on a Bruker
500 MHz Avance DRX spectrometer. Chemical shifts are
4.2. Complex 2
This compound was obtained following the above
procedure but with Li[C5H4(CH2)2PCy2] (green powder,
81% yield). 31P{1H} NMR (202 MHz, C6D6) d À6.0 (s,
PCy2). The ESR spectrum in toluene showed an eight-line

J. Goux et al. / Journal of Organometallic Chemistry 691 (2006) 3239–3244
3243
spectrum: giso = 1.9285; ATa,iso = 120.35 G. Anal. Calc.
for C29H45Cl2PTa (676.56): C, 51.47; H, 6.72. Found: C,
51.10; H, 6.60%.
2100–2900 (vs). Anal. Calc. for C39H60Cl4OPRuTa
(999.78): C, 46.85; H, 6.06. Found: C, 46.84; H, 6.18%.
4.7. Complex 7
4.3. Complex 3
To a solution of 5 (0.5 g, 0.50 mmol) in 10 mL of tolu-
ene, is added an excess of triethylamine. The mixture is stir-
red for 2 h at room temperature. Salts are filtered through a
path of celite, solvent is removed under vacuum to afford a
red powder (95% yield). 31P{1H} NMR (202 MHz, CDCl3)
A 25 ml Schlenk flask was charged under argon with 1
(0.23 g, 0.35 mmol), [(p-cymene)RuCl2]2 (0.11 g, 0.17
mmol) and degassed benzene. The mixture was stirred at
room temperature for 4 h during this time a brick red pre-
cipitate was slowly formed. The solvent was removed by fil-
tration and the red residue was dried under vacuum (brick-
red powder, 75% yield). 31P{1H} NMR (202 MHz, CDCl3)
d 21.4 (s, PPh2). The ESR spectrum in toluene showed an
eight-line spectrum: giso = 1.9238; ATa,iso = 113.03 G.
Anal. Calc. for C39H47Cl4PRuTa (970.65): C, 48.25; H,
4.89. Found: C, 48.01; H, 4.71%.
1
d 25.1 (s, PPh2). H NMR (500 MHz, CDCl3) d 0.80 (d,
i
i
J = 6.9 Hz, 3H, Pr), 0.84 (d, J = 6.9 Hz, 3H, Pr), 1.90
(s, 3H, CH3), 2.00 (s, 15H, Cp*), 2.44–2.48 (m, 2H, CH2),
2.54 (hept, J = 6.9 Hz, 1H, Pr), 2.80–2.84 (m, 2H, CH2),
i
5.07–5.14 (m, 2H, p-cymene), 5.27–5.31 (m, 2H, p-cymene),
5.58 (m, 1H, Cp), 5.63 (m, 1H, Cp), 5.71 (m, 1H, Cp), 5.73
(m, 1H, Cp), 7.48–7.51 (m, 6H, Ph), 7.91–7.95 (m, 4H, Ph).
IR (KBr, cmÀ1): mTa=O 810 (s). Anal. Calc. for
C39H47Cl3OPRuTa (951.20): C, 49.24; H, 4.99. Found: C,
49.10; H, 5.02%.
4.4. Complex 4
This compound was obtained following the above pro-
cedure but with 2 (brick-red powder, 69% yield). 31P{1H}
NMR (202 MHz, CDCl3) d 22.1 (s, PCy2). The ESR spec-
4.8. Complex 8
trum in toluene showed an eight-line spectrum: giso
1.9245; ATa,iso = 119.30 G. Anal. Calc. for C39H59Cl4PRu-
Ta (982.77): C, 47.66; H, 6.06. Found: C, 47.37; H, 5.90%.
=
This compound was obtained following the above pro-
cedure but with 6 (red powder, 93% yield). 31P{1H}
NMR (202 MHz, CDCl3) d 26.0 (s, PCy2). 1H NMR
i
(500 MHz, CDCl3) d 1.26 (d, J = 6.9 Hz, 6H, Pr), 1.30
i
4.5. Complex 5
(d, J = 6.9 Hz, 6H, Pr), 1.31–1.92 (m, 22H, Cy), 1.93 (s,
i
3H, CH3), 2.06 (s, 15H, Cp*), 2.32–2.33 (m, 1H, Pr),
A 25 ml Schlenk flask was charged under argon with 3
(0.33 g, 0.35 mmol) in 30 mL of degassed THF. The mix-
ture was stirred at room temperature under air atmosphere
for 12 h during this time a brick precipitate was slowly
formed. The resulting red suspension was filtered, the solid
washed with 2 · 5 mL of THF and dried under vacuum to
afford a red powder (40% yield). 31P{1H} NMR (202 MHz,
2.82–2.91 (m, 4H, CH2), 5.56–5.60 (m, 4H, p-cymene),
5.70 (m, 1H, Cp), 5.73 (m, 1H, Cp), 5.80 (m, 1H, Cp),
5.89 (m, 1H, Cp). IR (KBr, cmÀ1): mTa=O 813 (s). Anal.
Calc. for C39H59Cl3OPRuTa (963.32): C, 48.62; H, 6.18.
Found: C, 48.44; H, 6.38%.
4.9. Cyclopropanation
1
CDCl3) d 23.8 (s, PPh2). H NMR (500 MHz, CDCl3) d
i
0.87 (d, J = 6.9 Hz, 6H, Pr), 1.89 (s, 3H, CH3), 2.16 (s,
Cyclopropanation reactions were performed according
to the procedure described by Demonceau, Noels et al.
[13]. Ethyl diazoacetate (1 mmol diluted by styrene up
to 1 ml) was added during a period of 4 h with a syringe
pump to a solution of styrene (20 mmol) containing the
catalyst (0.01 mmol) and 1 mmol of decane (internal
standard). The reaction was stirred at 60 ꢁC during an
overall time of 4.25 h. Product yields were determinated
by GC using the experimentally measured cyclopro-
pane–decane response ratio.
i
15H, Cp*), 2.54 (hept, J = 6.9 Hz, 1H, Pr), 2.56–2.88 (m,
4H, CH2), 5.09–5.15 (m, 2H, p-cymene), 5.29–5.31 (m,
2H, p-cymene), 5.53 (m, 1H, Cp), 5.75 (m, 1H, Cp), 6.63
(m, 1H, Cp), 7.00 (m, 1H, Cp), 7.50–7.54 (m, 6H, Ph),
8.07–8.10 (m, 4H, Ph). IR (KBr, cmÀ1): mTaAOH 2100–
2900 (vs). Anal. Calc. for C39H48Cl4OPRuTa (987.66): C,
47.42; H, 4.91. Found: C, 47.59; H, 5.07%.
4.6. Complex 6
This compound was obtained following the above proce-
Acknowledgment
dure but with 4 (red powder, 43% yield). 31P{1H} NMR
1
(202 MHz, CDCl3) d 27.9 (s, PCy2). H NMR (500 MHz,
The authors thank Pr. A. Demonceau for helpful
discussions.
i
CDCl3) d 1.29 (d, J = 6.9 Hz, 6H, Pr), 1.30–2.04 (m, 22H,
Cy), 2.09 (s, 3H, CH3), 2.17 (s, 15H, Cp*), 2.54 (hept,
i
J = 6.9 Hz, 1H, Pr), 2.83–2.89 (m, 2H, CH2), 3.11–3.13
References
(m, 2H, CH2), 5.54–5.57 (m, 2H, p-cymene), 5.61–5.63 (m,
2H, p-cymene), 5.80 (m, 1H, Cp), 5.82 (m, 1H, Cp), 6.66
(m, 1H, Cp), 6.67 (m, 1H, Cp). IR (KBr, cmÀ1): mTa–OH
[1] (a) C. Cornelissen, G. Erker, G. Kehr, R. Fro¨hlich, Organometallics
24 (2005) 214;

3244
J. Goux et al. / Journal of Organometallic Chemistry 691 (2006) 3239–3244
[4] (a) L. Bareille, P. Le Gendre, P. Richard, C. Mo¨ıse, Eur. J. Inorg.
(b) C.S. Griffith, G.A. Koutsantonis, B.W. Skelton, A.H. White,
Angew. Chem., Int. Ed. 44 (2005) 3038;
(c) B. Stempfle, O. Gevert, H. Werner, J. Organomet. Chem. 681
(2003) 70;
Chem. 12 (2005) 2451;
(b) V. Comte, P. Le Gendre, P. Richard, C. Mo¨ıse, Organometallics
24 (2005) 1439;
´
(d) P. Braunstein, X. Morise, M. Benard, M.-M. Rohmer, R. Welter,
Chem. Commun. (2003) 610;
(c) P. Le Gendre, P. Richard, C. Mo¨ıse, J. Organomet. Chem. 605
(2000) 151.
(e) B.W. Wenzel, P. Lo¨nnecke, E. Hey-Hawkins, Organometallics 21
(2002) 2070;
[5] (a) J. Goux, P. Le Gendre, P. Richard, C. Mo¨ıse, J. Organomet.
Chem. 690 (2005) 301;
(f) M. Hofmann, W. Malisch, D. Schumacher, M. Lager, M. Nieger,
Organometallics 21 (2002) 3485;
(b) P. Le Gendre, V. Comte, A. Michelot, C. Mo¨ıse, Inorg. Chim.
Acta 350 (2003) 289;
(g) S. Kuwata, S.-I. Kabashima, N. Sugiyama, Y. Ishii, M. Hidai,
Inorg. Chem. 40 (2001) 2034;
(c) P. Le Gendre, M. Picquet, P. Richard, C. Mo¨ıse, J. Organomet.
Chem. 643–644 (2002) 231.
(h) C. Mattheis, P. Braunstein, A. Fischer, J. Chem. Soc., Dalton
Trans. (2001) 800;
[6] V.C. Gibson, J.E. Bercaw, W.J. Burton Jr., R.D. Sanner, Organo-
metallics 5 (1986) 976.
(i) T. Nagano, S. Kuwata, Y. Ishii, M. Hidai, Organometallics 19
(2000) 4176;
(j) L.H. Gade, Angew. Chem., Int. Ed. 39 (2000) 2659;
(k) N. Wheatley, P. Kalck, Chem. Rev. (1999) 3379.
[7] (a) J.A. Hunter, W.E. Lindsell, K.J. McCullough, R.A. Parr, M.L.
Scholes, J. Chem. Soc., Dalton Trans. (1990) 2145;
(b) C. Poulard, D. Perrey, G. Boni, E. Vigier, O. Blacque, M.M.
Kubicki, C. Mo¨ıse, Eur. J. Inorg. Chem. (2003) 633;
(c) C. Poulard, G. Boni, P. Richard, C. Mo¨ıse, J. Chem. Soc., Dalton
Trans. (1999) 2725.
[2] (a) J.P. Morgan, K. Kundu, M.P. Doyle, Chem. Commun. (2005)
3307;
´
(b) M.A.F. Hernandez-Gruel, J.J. Perez-Torrente, M.A. Ciriano,
[8] S. Serron, S.P. Nohan, Organometallics 14 (1995) 4611.
[9] J. Goux, P. Le Gendre, P. Richard, C. Mo¨ıse, Organometallics 24
(2005) 4902.
A.B. Rivas, F.J. Lahoz, I.T. Dobrinovitch, L.A. Oro, Organometal-
lics 22 (2003) 1237;
(c) B.E. Bosch, I. Brummer, K. Kunz, G. Erker, R. Fro¨hlich, S.
¨
Kotila, Organometallics 19 (2000) 1255;
[10] P. Van der Sluis, A.L. Spek, Acta Crystallogr., Sect. A 46 (1990) 194.
[11] R.W. Quan, J.E. Bercaw, W.P. Schaefer, Acta Crystallogr., Sect. C
47 (1991) 2057.
´
(d) M.A. Casado, J.J. Perez-Torrente, M.A. Ciriano, L.A. Oro, A.
´
Orejon, C. Claver, Organometallics 18 (1999) 3035;
[12] D.M. Antonelli, W.P. Schaefer, G. Parkin, J.E. Bercaw, J. Organo-
met. Chem. 462 (1993) 213.
[13] (a) F. Simal, A. Demonceau, A.F. Noels, Tetrahedron Lett. 39 (1998)
3493;
(e) Y. Yamaguchi, N. Susuki, T. Mise, Y. Wakatsuki, Organomet-
allics 18 (1999) 996;
(f) M.L.H. Green, N.H. Popham, J. Chem. Soc., Dalton Trans.
(1999) 1049;
(b) F. Simal, D. Jan, A. Demonceau, A.F. Noels, Tetrahedron Lett.
40 (1999) 1653;
(c) A.F. Noels, A. Demonceau, in: B. Cornils, W.A. Herrmann
(Eds.), Applied Homogeneous Catalysis with Organometallic Com-
pounds, vol. 2, Wiley–VCH, 2002, p. 793;
(d) F. Simal, A. Demonceau, A.F. Noels, D.R.T. Knowles, S.
O’Leary, P.M. Maitlis, O. Gusev, J. Organomet. Chem. 558 (1998)
163;
(g) F. Senocq, C. Randrianalimanana, A. Thorez, P. Kalck, R.
Choukroun, D. Gervais, Chem. Commun. (1984) 1376.
[3] (a) H. Butenscho¨n, Chem. Rev. 100 (2000) 1527;
(b) T.W. Graham, A. Llamazarez, R. McDonald, M. Cowie,
Organometallics 18 (1999) 3490;
(c) T.W. Graham, A. Llamazarez, R. McDonald, M. Cowie,
Organometallics 18 (1999) 3502;
(d) X. Dong He, A. Maisonnat, F. Dahan, R. Poilblanc, Organo-
metallics 8 (1989) 2618;
(e) W. Tikkanen, Y. Fujita, J.L. Petersen, Organometallics 5 (1986)
888;
(f) M.R. Rausch, B.H. Edwards, R.D. Rogers, J.L. Atwood, J. Am.
Chem. Soc. 105 (1983) 3882;
(g) J.C. Leblanc, C. Mo¨ıse, A. Maisonnat, R. Poilblanc, C. Charrier,
F. Mathey, J. Organomet. Chem. 231 (1982) C43.
(e) O. Tutusaus, S. Delfosse, A. Demonceau, A.F. Noels, R. Nunez,
C. Vinas, F. Teixidot, Tetrahedron Lett. 43 (2002) 983.
[14] (a) H. Nishiyama, K. Aoki, H. Itoh, T. Iwamura, N. Sakata, O.
Kurihara, Y. Motoyama, Chem. Lett. (1996) 1071;
(b) I.W. Davies, L. Gerena, D. Cai, R.D. Larsen, T.R. Verhoeven,
P.J. Reider, Tetrahedron Lett. 38 (1997) 1145.
[15] T. Kauffman, M. Bisling, J.H. Teuben, R. Konig, Angew. Chem.,
Int. Ed. Engl. 19 (1980) 328.