New 1,1′- or 1,2- or 1,3-bis(diphenylphosphino)ferrocenes

Article abstract of DOI:10.1016/S0022-328X(99)00736-6

The syntheses of ferrocenyl phosphines with bulky substituents are reported using the reaction between FeCl₂ and the suitably substituted cyclopentadienyl salts, LiC₅H₃-1,3-(PPh₂)₂, LiC₅H

Full text of DOI:10.1016/S0022-328X(99)00736-6

www.elsevier.nl/locate/jorganchem
Journal of Organometallic Chemistry 598 (2000) 365–373
New 1,1%- or 1,2- or 1,3-bis(diphenylphosphino)ferrocenes
Roland Broussier *, Emmanuelle Bentabet, Patrick Mellet, Olivier Blacque,
Patricia Boyer, Marek M. Kubicki, Bernard Gautheron
Laboratoire de Synthe`se et d’Electrosynthe`se Organome´talliques (UMR 5632), Uni6ersite´ de Bourgogne, 6, boule6ard Gabriel,
F-21000 Dijon, France
Received 20 September 1999; accepted 2 December 1999
Abstract
The syntheses of ferrocenyl phosphines with bulky substituents are reported using the reaction between FeCl2 and the suitably
substituted cyclopentadienyl salts, LiC5H3-1,3-(PPh2)2, LiC5H3-1-PPh2-3-tBu, LiC5H2-1,2-(PPh2)2-4-tBu. This strategy leads to bi-,
tri- and tetraphosphines, which cannot be obtained by the other access paths used to prepare substituted ferrocenes. [C5H3-1,3-
(PPh2)2](C5H5)Fe, [C5H3-1-PPh2-3-tBu]2Fe racemic and meso and [C5H2-1,2-(PPh2)2-4-tBu](C5H5)Fe have been characterized by
single-crystal X-ray diffraction studies. © 2000 Elsevier Science S.A. All rights reserved.
Keywords: Phosphine; Ferrocene
salt [6]. Analogous 1,2-phosphorylated cyclopentadiene,
1,2-(methylphenylphosphinoborane)cyclopentadiene,
has been described, but the preparation of the corre-
sponding ferrocene failed [7]. This paper is the result of
investigations on the diphosphino substitution of cy-
clopentadienyllithium itself and experiments on an al-
ternative cyclopentadienyl ligand obtained from the
tertiobutylcyclopentadienyllithium. The synthesis and
crystal structures of [C5H3-1,3-(PPh2)2](C5H5)Fe, [C5H3-
1-PPh2-3-tBu]2Fe racemic and meso and [C5H2-1,2-
(PPh2)2-4-tBu](C5H5)Fe are hereafter reported.
1. Introduction
Molecular architecture is an essential factor in the
behavior of bridging or chelating diphosphines. Fer-
rocene exhibits architecture leading to various diphos-
phines species. Most of these derivatives contain two
identical diphenylphosphino fragments directly at-
tached at the 1,1% positions on the ferrocene [1]. The
approach to create this 1,1% disubstitution was based on
the successful metalation of ferrocene itself or pre-
formed ferrocene with a specific side chain. Currently,
the search for synthetic methods is based on the use of
an adequate ferrocenic precursor, especially bromo- [2]
or silyl- [3] substituted products. For ferrocenes, with a
disposition of phosphino groups other than 1,1%, the
synthesis of 1,2-diphosphinoferrocene has been realized
only recently [4]. Previous attempts by direct metalation
of diphenylphosphinoferrocene were unsuccessful [5].
We report here the access paths to new ferro-
cenylphosphines using a complementary methodology,
i.e. the reaction of the appropriate cyclopentadienyl
salts with FeCl2. We have already performed a chemical
pathway leading to ferrocenylphosphines with 1,2-
diphosphino-substituted rings from the corresponding
1,2-bis(diphenylphosphino)trimethylcyclopentadienyl
2. Results and discussion
2.1. 1,3-Diphenylphosphinocyclopentadienyllithium and
corresponding ferrocenes
We have reinvestigated the synthesis of ferrocenes
with two or more diphenylphosphino substituents. The
lithiation of ferrocenylphosphines is easy, but with the
increasing number of substituents, a difficulty arises
with the isolation of pure compounds from mixtures of
isomers [8]. We then postulated that the problems of
isomers may be overcome if the ferrocenes were pro-
duced from the corresponding substituted cyclopenta-
dienes.
* Corresponding author.
0022-328X/00/$ - see front matter © 2000 Elsevier Science S.A. All rights reserved.
PII: S0022-328X(99)00736-6

366
R. Broussier et al. / Journal of Organometallic Chemistry 598 (2000) 365–373
recognition of the mode of substitution on the cy-
clopentadienyl ring in 1 from 1H-NMR data is not
clear, its 1,3-diphenylphosphinocyclopentadienyllithium
structure will be definitely proved by the synthesis of
corresponding ferrocenes.
The symmetrically (2) and unsymmetrically substi-
tuted (3) ferrocenes were synthesized as shown in
Scheme 1. The best route to 3 consists of a low-temper-
ature reaction (−78 to 20°C). This is mainly because 1
and FeCl2 initially form a 1/1 complex preventing the
formation of 2 or ferrocene itself [6] and that CpLi
further reacts with such a 1/1 complex on heating.
Literature data report on the failure [10] or at best on
formation of an intractable reaction mixture of te-
traphosphine isomers [8] in attempts of preparing com-
pound 2.
Single-crystal X-ray diffraction analysis of complex 3
(see Fig. 1 and Table 1) has been carried out in order to
recognize the substitution pattern. It reveals the pres-
ence of two independent ferrocenic molecules in the
asymmetric unit of C2/c space group.
An analysis of the shapes (heptuplet, quadruplet) of
proton resonances in the 1H-NMR spectrum of 1,3-
diphenylphosphinocyclopentadienyllithium (1) has been
attempted in the light of the X-ray structure of 3. For
1, the values of the coupling constants J(HꢀP)ortho,
J(HꢀP)meta and J(HꢀH)meta for the protons bound to
carbons 4 and 5 are essentially the same (2.2 Hz). The
coupling constant J(HꢀP)ortho of the proton carried by
carbon 2 is roughly double this value (3.8 Hz).
Referring to the 1,2 orientation effect of the thio-
phosphino group observed during the preparation of
thiodiphenylphosphinocyclopentadiene derivatives [11],
we have also investigated an alternative preparative
scheme using this cyclopentadiene as a precursor. Un-
fortunately, the sequence of reactions leading to 3,
Scheme 1.
Very little is known about the chemistry of bis-
(diphenylphosphino)cyclopentadiene. Nevertheless the
most characteristic feature of the 1,5-bis(diphenylphos-
phino)-2,3,4-trimethylcyclopenta-1,3-diene is the sigma-
tropic migration of one diphenylphosphino group
leading to a mixture of 1,2- and 1,3-diphosphino-substi-
tuted cyclopentadienes [9]. In the light of these results
an attractive hypothesis is to imagine that a 1,2–1,3
equilibrium takes place in the analogous non-methyl-
ated cyclopentadienes.
Promising information has been obtained from the
reaction in THF of diphenylphosphinocyclopentadi-
enyllithium with successively chlorodiphenylphosphine
1
and butyllithium solutions. In the H-NMR spectrum
(THF-d8 solution), two sets of multiplets, consistent
with two disubstituted species, are observed. It is the
only indication we got in speculating on the existence of
a mixture of 1,2 and 1,3 type. The signals of the minor
set disappear during treatment and only one species (1)
is extractable and isolable from the reaction mixture.
Moreover 1 is the only product obtained in toluene
instead of THF mixture. Unfortunately the shape of
signals in the 1H-NMR spectrum of 1 (heptuplet,
quadruplet) is not consistent with the predicted reso-
nance lineshapes [5] for both the 1,2- and 1,3-
diphenylphosphinocyclopentadienyl rings. Because the
Fig. 1. ORTEP drawing of two independent molecules of 3: 30% probability level.

R. Broussier et al. / Journal of Organometallic Chemistry 598 (2000) 365–373
367
Table 1
Molecular geometries of complexes 3, 5, 6 and 8
Complex
3
5
6
8
Molecule 1
Molecule 2
Molecule 1
Molecule 2
a
FeꢀCP1
1.645
1.641
1.659
2.056(3)
2.048(3)
1.660
2.050(6)
2.052(6)
1.647
2.046(7)
2.045(6)
2.037(6)
2.070(7)
1.429(8)
108.0
1.648
2.048(6)
2.045(6)
2.026(6)
2.073(7)
1.429(8)
108.0
FeꢀCCP (mean)
FeꢀCCP (Pl)
2.044(5) b
2.057(5)
2.041(5)
2.041(5)
2.052(5)
2.047(5)
FeꢀCCP (P2)
FeꢀCCP (tBu)
2.083(3)
1.427(4)
108.0
1.659
2.054(3)
2.054(3)
2.078(3)
1.424(4)
2.081(6)
1.413(7)
108.0
1.664
2.055(6)
2.066(6)
2.078(6)
1.419(7)
CCPꢀCCP (C5) mean
(CCPꢀCCPꢀCCP) mean
FeꢀCP2
1.425(7)
108.0
1.660
1.420(8)
108.0
1.648
1.660
2.037(9)
1.662
2.041(8)
FeꢀCCP (mean)
FeꢀCCP (Pl)
2.041(6)
2.030(6)
FeꢀCcp (tBu)
CCPꢀCCP (C5) mean
(CCPꢀCCPꢀCCP) mean
1.396(7)
108.0
1.806(6)
1.813(6)
1.393(9)
108.0
1.814(6)
1.811(6)
1.388(11)
108.0
1.806(7)
1.810(7)
1.392(11)
108.0
1.815(7)
1.825(7)
108.0
1.823(3)
108.0
1.813(6)
CCP ꢀP
1
CCP ꢀP
1.819(3)
1.517(4)
1.520(4)
178.4
4.49
1.810((6)
1.512(8)
1.501(8)
176.3
4.03
2
CCP ꢀCtBu
1.511(9)
1.523(9)
1
CCP ꢀCtBu
2
CPꢀFeꢀCP (°)
Tilt of C5 planes (°)
179.7
0.67
179.2
2.28
178.7
3.23
2.02
Deviations of substituents from C5 planes c
P1(CP )
−0.081
−0.021
−0.057
−0.119
−0.088
+0.124
−0.126
+0.037
−0.111
+0.012
1
P2(CP
)
1
P(CP )
−0.003
+0.178
+0.188
+0.188
+0.173
+0.174
2
CtBu(CP )
+0.173
+0.148
1
CtBu(CP )
2
Conformation
Twist angle d
Interm
19.2
Interm
16.7
Eclipsed
7.3
Staggered
25.6
Staggered
26.3
Staggered
27.7
a CP are the geometrical centers of C5 rings.
b Estimated S.D. for individual bonds.
c Sign (−) means the endo displacement (towards Fe atom), while (+) indicates the exo one.
d Twist angle is equal to 0° for ideal eclipsed, and 36° for ideal staggered conformations.
been prepared from the corresponding cyclopentadienyl
salts [14].
applied to thiodiphenylphosphinocyclopentadienyl-
lithium does not produce the 1,2 but the 1,3 isomer: the
1-thiophosphino-3-phosphino analog of 3.
Using this approach and starting from the ter-
tiobutylcyclopentadienyllithium, we have prepared a
cyclopentadiene with both tertiobutyl and diphenyl-
phosphino substituents (Scheme 2). In the presence of
tertiobutyl group the subsequent substitution occurs
at the i position and the 1,3-disubstituted cyclopentadi-
ene is obtained as a mixture of four tautomers: 1-
diphenylphosphino - 4 - tertiobutylcyclopenta - 1,4 - diene
2.2. 1-Diphenylphosphino-3-tertiobutylcyclopentadienyl-
lithium and 1,1%-bis(diphenylphosphino)-3,3%-ditertio-
butylferrocene racemic and meso
This investigation on the dissymetrically disubstituted
cyclopentadienyl ligand area was performed with the
aim of obtaining the two diastereoisomeric forms of
sterically crowded ferrocenic phosphines. Previously re-
ported studies [12] show the inability of the sequence
metalation-reaction with electrophile applied to fer-
rocene in the preparation of the two diastereoisomeric
forms of 1,1%-bis(diphenylphosphino)-3,3%-bis (trimethyl-
silyl)ferrocene. We can consider that such a behavior
will be the same with the known 3,3% dilithiated 1,1%-
bis(tertiobutyl)ferrocene [13]. On the other hand, a
large number of ferrocenes with bulky substituents have
(45%),
1-diphenylphosphino-3-tertiobutylcyclopenta-
1,3-diene (45%), 1-diphenylphosphino-3-tertiobutylcy-
clopenta-2,4-diene (3%) and 1-diphenylphosphino-3-
tertiobutylcyclopenta-1,4-diene or 1-diphenylphos-
phino-4-tertiobutylcyclopenta-1,3-diene (7%). The iso-
mers exhibit small but significant differences of the
chemical shifts for substituents in 31P- or 1H-NMR
spectra (see Section 4).
Treatment of the above mixture of phosphines with
n-butyllithium in THF gave 1-diphenylphosphino-3-ter-

368
R. Broussier et al. / Journal of Organometallic Chemistry 598 (2000) 365–373
Scheme 2.
tiobutylcyclopentadienyllithium (4) in quantitative
yield. This salt has proven to be a convenient starting
material for the preparation of two diastereoisomeric
iron metallocenes (166 and 177°C melting points) in
60/40 ratio. Analytical and spectroscopic data (1H-, 31P-
and 13C-NMR) support the formulation presented in
Scheme 2, but despite the differences observed, the
attribution of meso form 5 or racemic form 6 could not
be achieved. We can only state at this point that species
F166°C displays a more complicated 13C-NMR spec-
trum than that of F177°C, for which long-range phos-
phorus–carbon coupling is seen as in racemic 1,1%-bis-
(diphenylphosphino) - 3,3% - bis(trimethylsilyl)ferrocene
[12]. The structures of these products (5 and 6) have
been definitively recognized on the basis of X-ray
analyses (Figs. 2 and 3 and Table 1).
Like other X-ray structures reported in this paper,
those of 5 and 6 bear the symmetry center excluding
any speculation about the polar properties of these
molecules. The crystals of 5 are built of (S, R) and
(R, S) molecules (meso structure), while those of 6
contain the (S, S) and (R, R) isomeric set of racemic
molecules.
Fig. 2. ORTEP drawing of 5: 30% probability level
2.3. 1,2-Bis(diphenylphosphino)-4-tertiobutylferrocene
We have shown the marked preference for 3-substitu-
tion in the orientation effects of ꢀPPh2 versus ꢀPPh2
and ꢀtBu versus ꢀPPh2. The combined directive influ-
ence of the two substituents in 1-diphenylphosphino-3-
tertiobutylcyclopentadienyllithium upon the reaction
site for a subsequent attack by Ph2PCl gave the exclu-
sive formation of 1,2-bis(diphenylphosphino)-4-ter-
tiobutyl arrangement. This route allows a new and easy
access to cyclopentadienes with two diphenylphosphino
groups in vicinal position. 1,2,3-Trimethylcyclopentadi-
enyl salts already proved that they were good candi-
dates for this preparation [6].
Fig. 3. ORTEP drawing of 6: 30% probability level
The reaction of
4
(Scheme 3) with chloro-
diphenylphosphine gives a trisubstituted cyclopentadi-
ene as a mixture of two isomers, 1,2-bis(diphenylphos-
phino)-4-tertiobutylcyclopenta-1,3-diene and 1,2-bis-
(diphenylphosphino)-4-tertiobutylcyclopenta-2,4-diene,
in a 80/20 ratio. The mixture is then deprotonated with

R. Broussier et al. / Journal of Organometallic Chemistry 598 (2000) 365–373
369
rocenic core as generally reported for alkyl-substituted
ferrocenes, while the PPh2 ones may give rise either to
the exo (6) or to the endo (or in plane) deviations (3, 5,
8). Steric hindrances are thus responsible for the devia-
t
tions observed: bulky and rigid Bu group bound to the
carbon atom of C5 ring with short C(Cp)ꢀC(tBu) (1.51
,
A) moves outside, while the larger and more flexible
,
PPh2 groups with C(Cp)ꢀPPh2 distances close to 1.81 A
are able to deviate in both the exo and the endo
positions.
The conformations of the C5 rings are intermediate
between the eclipsed and staggered, being closer to the
eclipsed one in 5, the staggered one in 6 and 8 and
clearly intermediate in 3.
4. Experimental
Scheme 3.
4.1. General considerations
BuLi yielding 7. After the coupling of 7 with FeCl2, the
resulting 1/1 intermediate reacts cleanly with CpLi af-
fording 8. It is noteworthy that 8 thus formed, is only
contaminated by a very small amount of unsubstituted
ferrocene and that no of symmetrical tetraphosphine
species has been detected.
X-ray structure analysis of 8 has been carried out. As
in the case of unsymmetrical complex 3, 8 crystallizes
with two independent molecules in the asymmetric unit
(Fig. 4 and Table 1).
Reactions were carried out in an atmosphere of
argon by means of conventional Schlenk techniques.
Solvents were dried and deoxygenated before distilla-
tion from sodium benzophenone ketyl or NaꢀK alloy.
Elemental analyses were performed by the Service cen-
tral d’analyses du CNRS. Mass spectra (electronic ion-
ization 70 eV) were recorded on a Kratos concept IS
machine. 1H-, 31P- and 13C-NMR spectra were recorded
on a Bruker AC 200 (special abbreviations: pqd,
pseudo quadruplet; pt, pseudo triplet; pd, pseudo dou-
blet; numerotation of Cp ring refer to ORTEP drawing
numerotation; for 2, 6 and 8, the spin system for each
of the carbon atoms of phenyl (i, o, m, p) is of the
AA%X (A=A%=31P, X=13C) limiting type [12,15]).
3. Crystallographic studies
All organometallic molecules have usual ferrocenic
geometries. Their selected metric parameters are gath-
ered in Table 1. All of them bear two PPh2 substituents
in 1,3 (3), 1,1% (5 and 6) or 1,2 (8) positions reached
4.2. Preparation of 1
t
with 3,3% (5 and 6) and 4 (8) Bu substitutions. Both
To 10.05 g (39.2 mmol) of diphenylphosphinocy-
clopentadienyllithium [16] in 200 ml toluene was added
at −80°C, 6.3 ml (35 mmol) of chlorodiphenylphos-
phine. The solution turned orange after stirring for 2 h
at room temperature (r.t.). The mixture was filtered, the
lithium chloride was washed with 40 ml of hexane and
the solution was evaporated in vacuo leading to an
orange oil. To the toluene solution of oil were added at
−80°C, 28 ml of butyllithium (1.39 M in diethyl ether,
39 mmol). Upon this addition, butane was evolved and
the solution turned yellow. After stirring at r.t. for 14 h,
a precipitate appeared. The mixture was filtered and the
precipitate was washed twice with 30 ml hexane. Then,
the solution was evaporated in vacuo and 13.04 g (29.5
mmol, yield=90%) of a white air-sensitive powder 1,
was isolated. 1H-NMR (THF-d8): l 6.06 (pqd, 2H,
3JHꢀP=2.2, 4JHꢀH=2.2, 4JHꢀP=2.2 Hz), 6.32 (hept,
1H, 3JHꢀP=3.8, 4JHꢀH=2.2 Hz). 31P-NMR (THF-d8): l
−15.83 (s).
unsymmetrical (two different Cp rings) complexes 3
and 8 crystallize with two independent molecules in the
asymmetric units of the corresponding C2/c and P21/c
monoclinic space groups. One observes that the FeꢀCP
(geometrical center of C5 ring) distances in asymmetri-
cal complexes 3 and 8 are shorter (except molecule 2 in
3) for substituted rings than for the non-substituted
C5H5 ones. Intuitively, one would expect an inverse
relation. An explanation for this is furnished by the
,
CꢀC bond lengths found for substituted (1.42–1.43 A)
,
and non-substituted (1.39–1.40 A) rings. The substi-
tuted rings are larger, and consequently may be closer
to the metal than the smaller C5H5 ones. The C5 planes
are roughly parallel in all molecules. However, one
states that the corresponding tilt angles increase clearly
(from 0.7 to 4.5°) with the degree of substitution i.e.
t
3B8B5 and 6. The Bu substituents exhibit an exo
(outside) deviation with respect to the (C5)2Fe fer-

370
R. Broussier et al. / Journal of Organometallic Chemistry 598 (2000) 365–373
Fig. 4. ORTEP drawing of two independent molecules of 8: 30% probability level.
mmol) of 2. The solid was recrystallized in hot hexane
4.3. Preparation of 2
and orange crystals of 3 were obtained, m.p.=109°C.
Anal. Calc. for C34H28FeP2: C, 73.66; H, 5.09. Found
C, 73.85; H, 5.12%. H-NMR (CDCl3): l 3.98 (s, 5H,
To 0.38 g (2.99 mmol) of iron dichloride in 20 ml
THF were added at r.t. 2.64 g (5.99 mmol, two molar
equivalent) of 1 in 50 ml THF. After refluxing for 4 h,
the reaction mixture was filtered on 2 cm of a silica gel
and the solvent was evaporated in vacuo. The oil was
chromatographed on a silica gel column with toluene–
hexane (1:1), and an orange solution was obtained.
Then the solvent was removed to give 2 g of 2 (2.16
mmol, yield=73%) as an orange air stable solid,
m.p.=180°C. Anal. Calc. for C58H46FeP4: C, 75.50; H,
1
Cp), 4.13 (s, 1H, Cp), 4.28 (s, 2H, Cp), 7.35 (m, 20H,
Ph). 31P-NMR (CDCl3): l −19.37 (s). 13C-NMR
2
3
(C6D6): l 70.3 (s, Cp), 75.4 (dd, JPC=14, JPC=3.5
2
Hz, C4/C5Cp), 77.7 (pt, JPC=15 Hz, C2Cp), 79.5 (dd,
1JPC=8, 3JPC=3 Hz, C1/C3Cp), 128.3 (d,3JPC=6.5 Hz,
m-Ph), 128.7 (d, 4JPC=4 Hz, p-Ph), 133.4 (d, 2JPC=9.5
2
Hz, o-Ph), 133.7 (d, JPC=9.5 Hz, o%-Ph), 138.8 (m,
i-Ph/i%-Ph). EI-MS (200°C): m/z (%): 554 (100) [M+],
477 (20) [M+−Ph].
1
5.02. Found C, 75.30; H, 4.93%. H-NMR (C6D6): l
3.97 (s, 2H, Cp), 4.40 (s, 1H, Cp), 7.03–7.50 (m, 20H,
Ph). 31P-NMR (C6D6): l −22.46 (s). 13C-NMR (C6D6):
l 76.2 (m, C1Cp), 81.0 (m, C2/C3Cp), 83.0 (m, C5Cp),
4.5. Preparation of 4
To 3.1 g (24 mmol) of tertiobutylcyclopentadienyl-
lithium in 70 ml toluene were added at −80 °C, 4.2 ml
(23.4 mmol) of chlorodiphenylphosphine. The solution
turned orange after stirring for 2 h at r.t. The mixture
was filtered and lithium chloride was washed with 30 ml
of hexane. The solution was evaporated in vacuo and
6.5 g (21.2 mmol, yield=91%) of an orange oil, mix-
ture of cyclopentadienes, were isolated.
128.2 (pt, JPC+P%C=7 Hz, p-Ph), 128.5 (pd, JPC+P%C
=
23 Hz, m-Ph), 133.1 (pt, JPC+P%C=30 Hz, o-Ph), 134.0
(pt, JPC+P%C=30 Hz, o%-Ph), 133.3 (pt, JPC+P%C=60
Hz, o%%-Ph), 133.7 (pt, JPC+P%C=60 Hz, o%%%-Ph), 139.3
(m, i-Ph). EI-MS (200°C): m/z (%): 923 (100) [M+], 845
(10) [M+−Ph], 737 (10) [M+−PPh2].
1H-NMR (C6D6) non-assigned signals for ethylenic
and phenyl protons: l 6.00 (m, 1H), 6.05 (m, 1H), 6.25
(m, 1H), 6.62 (m, 1H), 7.30–8.05 (m, 20H).
4.4. Preparation of 3
To 0.291 g (2.3 mmol) of iron dichloride in 15 ml
THF was added a mixture of 1.02 g (2.3 mmol) of 1
and 0.166 g (2.3 mmol) of cyclopentadienyllithium in 40
ml THF at −80°C. After stirring for 2 h at r.t., the
solution turned violet–brown. Then the mixture was
filtered on 2 cm of celite and, following solvent re-
moval, an oil was obtained. This oil was chro-
matographed on a silica gel column with toluene–
hexane (2:3). In the order of elution and after the
solvent was evaporated in vacuo from each fraction,
three products were obtained: ferrocene, 495 mg (0.89
mmol, yield=39%) of 3 and finally 74 mg (8×10−2
1-Diphenylphosphino-4-tertiobutylcyclopenta-1,4-di-
1
t
ene: H-NMR (C6D6): l 0.98 (s, Bu), 2.93 (m, CH2):
31P-NMR (C6D6): l −19.14 (s).
1-Diphenylphosphino-3-tertiobutylcyclopenta-1,3-di-
1
t
ene: H-NMR (C6D6): l 1.06 (s, Bu), 3.02 (m, CH2):
31P-NMR (C6D6): l −19.14 (s).
1-Diphenylphosphino-3-tertiobutylcyclopenta-2,4-di-
ene: 31P-NMR (C6D6): l −10.86 (s).
1-Diphenylphosphino-3-tertiobutylcyclopenta-1,4-di-
ene or 1-diphenylphosphino-4-tertiobutylcyclopenta-
1,3-diene: 31P-NMR (C6D6): l −20.12 (s).

R. Broussier et al. / Journal of Organometallic Chemistry 598 (2000) 365–373
371
To 6.5 g (21.2 mmol) of the previous oil in 100 ml
4.7. Preparation of 7
toluene were added at −20°C, 18 ml of butyllithium
(1.46 M in diethylether, 26 mmol). Upon this addition,
butane was evolved and the solution turned yellow.
After stirring at r.t. for 14 h, a precipitate appeared.
The mixture was filtered and the precipitate was washed
with 30 ml of toluene. Then, the solution was evapo-
rated in vacuo and 5.73 g (18.3 mmol, yield=87%) of
To 5.73 g (18 mmol) of 4 in 50 ml toluene were
added at −80°C, 3.2 ml (17.8 mmol) of chloro-
diphenylphosphine. The solution turned orange after
stirring for 4 h at r.t. The mixture was filtered and
lithium chloride was washed twice with 10 ml of
toluene. The solution was evaporated in vacuo and 6.4
g (13 mmol, yield=73%) of trisubstituted cyclopentadi-
enes as an orange oil, were isolated.
1
a white air sensitive powder, 4, was isolated, H-NMR
t
(THF-d8): l 1.24 (s, 9H, Bu), 5.73 (m, 1H, Cp), 5.88
(m, 1H, Cp), 5.97 (m, 1H, Cp), 7.12–7.31 (m, 10H, Ph).
1,2-Bis(diphenylphosphino)-4-tertiobutyl-1,3-diene:
t
31P-NMR (THF-d8): l −15.5 (s).
1H-NMR (C6D6): l 0.83 (s, 9H, Bu), 3.24 (s, 1H,
CHPPh2), 6.30 (m, 2H, CHꢁC), 6.9–7.2 (m, 20H, Ph).
3
4.6. Preparation of 5 and 6
31P-NMR (C6D6): l −26 (pqd, 2P, JPꢀP=84 Hz).
1,2-Bis(diphenylphosphino)-4-tertiobutyl-2,4-diene:
1H-NMR (C6D6): l 0.84 (s, 9H, tBu), 3.24 (s, 2H, CH2),
6.34 (m, CHꢁC), 7.41–7.54 (m, 20H, Ph). 31P-NMR
To 0.45 g (3.5 mmol) of iron dichloride in 40 ml THF
were added at 0°C, 2.10 g (6.7 mmol, two molar
equivalent) of 4 in 80 ml THF. After stirring at 0°C for
30 min and at r.t. for 15 h, the solvent was removed
and the resulted brown oil was extracted with 60 ml of
pentane. The brown mixture was then filtered and the
solvent was evaporated in vacuo. The oil was chro-
matographed on a silica gel column with toluene–hex-
ane (1:2). In order of elution and after the solvent was
evaporated in vacuo from each fraction, two products
were obtained: 320 mg (0.48 mmol, yield=14%) of an
orange solid, 5 and 200 mg (0.3 mmol, yield=9%) of
an orange solid, 6.
3
(C6D6): l −1.5 (d, 1P, JPꢀP=84 Hz), −20.5 (d, 1P,
3JPꢀP=84 Hz).
To 6.4 g (13 mmol) of the previous oil in 70 ml
toluene were added at 0°C, 10 ml of butyllithium (1.46
M in diethylether, 14.6 mmol). Upon this addition,
butane was evolved and the solution turned yellow.
After stirring at r.t. for 14 h, a precipitate appeared.
The mixture was filtered and the precipitate was washed
with 15 ml of hexane. Then, the solution was evapo-
rated in vacuo and 4.12 g (8.3 mmol, yield=57%) of a
1
white air sensitive powder 7, were isolated. H-NMR
t
Data for 5: m.p.=177°C. Anal. Calc. for
C42H44FeP2: C, 75.66; H, 6.65. Found C, 75.64; H,
(THF-d8): l 1.17 (s, 9H, Bu), 5.88 (m, 2H, Cp), 7.00–
7.34 (m, 20H, Ph). 31P-NMR (THF-d8): l −18.82 (s).
1
t
6.89%. H-NMR (C6D6): l 1.23 (s, 18H, Bu), 3.83 (m,
2H, Cp), 3.98 (m, 2H, Cp), 4.30 (m, 2H, Cp), 7.01–7.64
(m, 20H, Ph). 31P-NMR (C6D6): l −19.52 (s). 13C-
NMR (C6D6): l 31.0 (s, C(tBu)), 32.0 (s, Me(tBu)), 68.5
(s, C4Cp), 71.4 (s, C2/C5Cp), 74.0 (d, 1JPꢀC=32 Hz,
C1Cp), 76.3 (m, C2/C5Cp), 105.8 (s, C3Cp), 129.3 (s,
4.8. Preparation of 8
At −40°C, a yellow solution of 4.1 g of 7 (8.25
mmol) in 40 ml THF was added to 1.1 g (8.7 mmol) of
iron dichloride in 20 ml THF. After stirring for 2 h at
r.t., the solution turned violet. Then, 0.67 g (9.3 mmol)
of cyclopentadienyllithium in 20 ml THF was added to
the reaction mixture at −40°C, and agitation was
maintained during 1 h at r.t. The THF was evaporated
and replaced by 70 ml of toluene. The brown mixture
was refluxed for 16 h and filtered. Following solvent
removal, washing with hexane and drying under reduce
pressure, a yellow solid identified as 8 was obtained.
The product was crystallized in ethanol–water to ob-
tain 3.4 g (5.6 mmol, yield=68%) of orange crystals,
m.p.=176°C. Anal. Calc. for C38H36FeP2: C, 74.76; H,
2
p-Ph), m-Ph not observed (solvent), 132.6 (d, JPC=18
Hz, o-Ph), 135.4 (d, 2JPC=21 Hz, o%-Ph), 138.5 (d,
1JPC=11.5 Hz, i-Ph), 141.0 (d, 1JPC=13 Hz, i%-Ph).
EI-MS (200°C): m/z (%): 666 (100) [M+], 589 (30)
[M+−Ph], 481 (20) [M+−PPh2], 361 (10) [M+−
C5Ht2BuPPh2].
Data for 6: m.p.=166°C. Anal. Calc. for
C42H44FeP2: C, 75.66; H, 6.65. Found C, 75.46; H,
1
t
6.66%. H-NMR (C6D6): l 0.96 (s, 18H, Bu), 3.95 (m,
2H, Cp), 4.16 (m, 2H, Cp), 4.20 (m, 2H, Cp), 7.02–7.85
(m, 20H, Ph). 31P-NMR (C6D6): l −22.01 (s). 13C-
NMR (C6D6): l 30.7 (s, C(tBu)), 31.5 (s, Me(tBu)), 69.0
(s, C4Cp), 71.3 (s, C2/C5Cp), 74.5 (m, C1Cp), 76.1 (m,
C2/C5Cp), 105.7 (s, C3Cp), 129.3 (s, p-Ph), m-Ph not
observed (solvent), 132.6 (pt, JPC+P%C=18 Hz, o-Ph),
136.0 (pt, JPC+P%C=23 Hz, o%-Ph), 138.9 (pt, JPC+
P%C=12 Hz, i-Ph), 142.5 (pt, JPC+P%C=11.5 Hz, i%-Ph).
EI-MS (200°C): m/z (%): 666 (100) [M+], 589 (30)
[M+−Ph], 481 (20) [M+−PPh2], 361 (10) [M+−
C5Ht2BuPPh2].
1
5.94. Found C, 74.47; H, 6.03%. H-NMR (C6D6): l
t
1.07 (s, 9H, Bu), 4.05 (s, 5H, Cp), 4.25 (s, 2H, Cp),
6.87–7.76 (m, 20H, Ph). 31P-NMR (C6D6): l −24.3
(s). 13C-NMR (C6D6): l 31.0 (s, C(tBu)), 31.6 (s,
Me(tBu)), 71.2 (s, Cp), 83.0 (pt, 1+2JPC+P%C=19 Hz,
C1/C2Cp), 106.3 (s, C3/C5Cp), 129.2 (s, p-Ph), m-Ph not
observed (solvent), 133.6 (pt, 2+5JPC+P%C=20 Hz, o-
Ph), 135.5 (pt, 2+5JPC+P%C=22 Hz, o%-Ph), 139.5 (pt,
1+4JPC+P%C=8 Hz, i-Ph), 140.4 (pt, 1+4JPC+P%C=12

372
R. Broussier et al. / Journal of Organometallic Chemistry 598 (2000) 365–373
Table 2
Crystallographic data for complexes 3, 5, 6 and 8.
Complex
3
5
6
8
Molecular formula
Formula weight (g)
Colour, shape
Dimensions (mm)
Crystal system
C34H28FeP2
554.35
Amber, irregular
0.5×0.3×0.3
Monoclinic
C2/c (15)
42.279(5)
11.378(3)
28.966(5)
C
666.56
Amber, prism
0.4×0.4×0.3
Triclinic
42H44FeP2
C42H44FeP2
666.56
C38H36FeP2
610.46
Amber, prism
0.2×0.2×0.15
Monoclinic
P21/c (14)
15.744(3)
Amber, irregular
0.25×0.2×0.15
Monoclinic
P21/c (14)
16.946(4)
(
Space group
P1
,
a (A)
10.9097(6)
11.777(1)
15.276(1)
79.31
69.99(1)
79.20(1)
1795.8(3)
2
,
b (A)
11.033(2)
20.803(3)
13.566(6)
29.427(7)
,
c (A)
h (°)
i (°)
k (°)
126.75(1)
96.63(1)
105.49(2)
3
,
V (A )
11165(4)
16
3589(1)
4
6519(4)
8
Z
F(000)
4608
704
1.233
0.71073
0.537
296(1)
−1.0
ꢀ−2q
2.49–26.28
7665
1408
2560
zcalc. (g cm−1
)
1.319
0.71073
0.676
296(1)
−0.7
ꢀ
1.233
0.71073
0.537
296(1)
−4.0
ꢀ
1.244
0.7073
0.585
296(1)
0.0
ꢀ−2q
2.08–22.77
9057
,
Radiation, u (Mo–Ka) (A)
Linear absorption, v (mm−1
Temperature (K)
Linear decay (%)
Scan type
)
q range (°)
Measured
2.31–24.64
9730
2.09–19.98
3764
Unique
5299
7268
3334
7788
With [I\2|(I)]
Parameters
4537
667
0.048
0.099
1.060
+0.29/−0.24
5423
406
0.043
0.114
1.134
+0.30/−0.27
1944
406
0.042
0.080
0.986
+0.24/−0.25
3236
739
0.051
0.137
0.943
+0.29/−0.24
Final R(F2): R1
wR2
Goodness-of-fit
−3
,
zmax/zmin (e A
)
Hz, i%-Ph). EI-MS (200°C): m/z (%): 610 (100) [M+],
595 (70) [M+−CH3], 553 (30) [M+−tBu], 425 (30)
[M+−PPh2], 240 (10) [M+−2PPh2], 183 (70) [M+−
tBu2PPh2].
117661 (structure of 3), CCDC-117662 (structure of 5),
CCDC-117663 (structure of 6) and CCDC-117664
(structure of 8). Copies of the data can be obtained free
of charge on application to CCDC, 12 Union Road,
Cambridge CB2 1EZ, UK (Fax: +44-1223-336033;
e-mail: deposit@ccdc.cam.ac.uk).
4.9. X-ray crystallography
All measurements have been carried out at 296 K on
an Enraf–Nonius CAD4 diffractometer. The pertinent
crystallographic data are given in Table 2. The unit
cells have been determined from 25 randomly selected
reflections (CAD4-EXPRESS) [17]. Intensity data have
been reduced with PROCESS in MOLEN package [18]
with neutral-atom scattering factors taken from the
usual source. All structures were solved by direct meth-
ods (SHELXS97) [19] and refined by using the SHELXL97
library [20].
References
[1] (a) T. Hayashi, A. Togni (Eds.), Ferrocenes, VCH, Weinheim,
1995. (b) H.B. Kagan, Bull. Soc. Chim. Fr. 135 (1988) 846.
[2] (a) I.R. Butler, R.L. Davies, Synthesis (1996) 1350. (b) H.
Brunner, M. Janura, Synthesis (1998) 45. (c) T.Y. Dong, C.K.
Chang, J. Chin. Chem. Soc. 45 (1998) 577.
[3] D. Price, N.S. Simpkins, Tetrahedron Lett. 36 (1995) 6135.
[4] O. Riant, G. Argouarch, D. Guillaneux, O. Samuel, H.B. Ka-
gan, J. Org. Chem. 63 (1998) 3511.
[5] I.A. Butler, L.J. Hobson, S.M.E. Macan, D.J. Williams, Polyhe-
dron 12 (1993) 1901.
[6] R. Broussier, S. Ninoreille, C. Bourdon, O. Blacque, C. Ni-
noreille, M.M. Kubicki, B. Gautheron, J. Organomet. Chem.
561 (1998) 85.
5. Supplementary material
[7] E.B. Kaloun, R. Merde`s, J.P. Geneˆt, J. Uziel, S. Juge´, J.
Organomet. Chem. 529 (1997) 455.
[8] I.R. Butler, W.R. Cullen, Organometallics 5 (1986) 2537.
[9] R. Broussier, S. Ninoreille, C. Legrand, B. Gautheron, J.
Organomet. Chem. 532 (1997) 55.
Crystallographic data (excluding structure factors)
for the structures reported in this paper have been
deposited with the Cambridge Crystallographic Data
Centre as supplementary publication nos. CCDC-

R. Broussier et al. / Journal of Organometallic Chemistry 598 (2000) 365–373
373
[10] A.G. Osborne, R.H. Whiteley, J. Organomet. Chem. 162 (1978)
79.
[16] C.P. Casey, R.M. Bullock, W.C. Fultz, A.L. Rheingold,
Organometallics 1 (1982) 1591.
[11] F. Mathey, J.P. Lampin, Tetrahedron 31 (1975) 2685.
[12] R.A. Brown, A. Houlton, R.M.G. Roberts, J. Silver, C.S.
Frampton, Polyhedron 11 (1992) 2611.
[13] D.L. Compton, T.B. Rauchfuss, Organometallics 13 (1994)
4367.
[17] Enraf–Nonius, Delft, CAD
lands, 1992.
[18] C.K. Fair, Enraf–Nonius, MOLEN, An Interactive Intelligent
System for Crystal Structure Analysis, Delft, The Netherlands,
1990.
4 EXPRESS, version 5.1, The Nether-
[14] R.P. Hughes, J.R. Lomprey, A.L. Rheingold, B.S. Haggerty,
G.P.A. Yap, J. Organomet. Chem. 517 (1996) 89.
[15] S. Ninoreille, R. Broussier, R. Amardeil, M.M. Kubicki, B.
Gautheron, Bull. Soc. Chim. Fr. 132 (1995) 128.
[19] G.M. Sheldrick, SHELXS97, Program for the Solution of Crystal
Structures, University of Go¨ttingen, Germany, 1997.
[20] G.M. Sheldrick, SHELXL97, Program for the Refinement of
Crystal Structures, University of Go¨ttingen, Germany, 1997.
.