Bidentate ferrocenylphosphines and their palladium(II)dichloride complexes - X-ray structural and NMR spectroscopic investigations and first results of their characteristics in the Pd-catalysed cooligomerisation of 1,3-butadiene with CO2

Article abstract of DOI:10.1016/S0022-328X(99)00670-1

The chiral 1,1′-bis(di(+)-menthylphosphino)ferrocene (dmenpf, 1b) and achiral 1,1′-bis(diisopropylphosphino)ferrocene (disoppf, 1a) were prepared from the corresponding tertiary chlorophosphines 2b and 2a and the dilithiated ferrocene-TMEDA complex as analytically pure crystals. The synclinic eclipsed conformation of the Cp rings and the Cp(1)-Fe-Cp(1)′ angle in 1b was determined to be 175.0(2)° by X-ray structure analysis. With H₂[PdCl₄] 1a forms the bimetallic complex (disoppf)PdCl₂ (3a). In contrast to the structure of the free ligand disoppf (1a), the X-ray structure of 3a and the NMR spectra in solution as well as in the solid state show that the P atoms are chemically and magnetically equivalent. The conformation of the Cp rings converts from an eclipsed to a staggered conformation. The ferrocene-based ligands show significant activity in the Pd-catalysed cooligomerisation of 1,3-butadiene with CO₂

Full text of DOI:10.1016/S0022-328X(99)00670-1

www.elsevier.nl/locate/jorganchem
Journal of Organometallic Chemistry 597 (2000) 139–145
Bidentate ferrocenylphosphines and their palladium(II)dichloride
complexes — X-ray structural and NMR spectroscopic
investigations and first results of their characteristics in the
Pd-catalysed cooligomerisation of 1,3-butadiene with CO2
Anja R. Elsagir a,1, Franz Gaßner b, Helmar Go¨rls c, Eckhard Dinjus b,*
a Projektgruppe ‘CO2-Chemie’, Friedrich-Schiller-Uni6ersita¨t Jena, Lessingstraße 12, D-07743 Jena, Germany
b Forschungszentrum Karlsruhe, Institut fu¨r Technische Chemie, Bereich Chemisch Physikalische Verfahren, Postfach 3640,
D-76351 Karlsruhe, Germany
c Institut fu¨r Anorganische Chemie, Friedrich-Schiller-Uni6ersita¨t Jena, D-07743 Jena, Germany
Received 7 September 1999; received in revised form 25 October 1999
Dedicated to Professor Stanis*law Pasynkiewicz on the occasion of his 70th birthday.
Abstract
The chiral 1,1%-bis(di(+)-menthylphosphino)ferrocene (dmenpf, 1b) and achiral 1,1%-bis(diisopropylphosphino)ferrocene
(disoppf, 1a) were prepared from the corresponding tertiary chlorophosphines 2b and 2a and the dilithiated ferrocene–TMEDA
complex as analytically pure crystals. The synclinic eclipsed conformation of the Cp rings and the Cp(1)ꢀFeꢀCp(1)% angle in 1b
was determined to be 175.0(2)° by X-ray structure analysis. With H2[PdCl4] 1a forms the bimetallic complex (disoppf)PdCl2 (3a).
In contrast to the structure of the free ligand disoppf (1a), the X-ray structure of 3a and the NMR spectra in solution as well as
in the solid state show that the P atoms are chemically and magnetically equivalent. The conformation of the Cp rings converts
from an eclipsed to a staggered conformation. The ferrocene-based ligands show significant activity in the Pd-catalysed
cooligomerisation of 1,3-butadiene with CO2 © 2000 Elsevier Science S.A. All rights reserved.
Keywords: Phosphines; Chiral ligands; Ferrocenes; X-ray structure; NMR; CPMAS; Catalysis; CO2; Lactone
1. Introduction
have been the subject of several reports [3]. Another
point of interest is the influence on the selectivity and
the speed of reactions using these complexes in homo-
geneous catalysis.
Here we report on the synthesis and structural char-
acterisation of some bidentate ferrocenylphosphines
(Fig. 1) and their palladium(II)dichloride complexes.
First results of the Pd-catalysed d-lactone synthesis will
be presented (see Fig. 6).
Ferrocenylphosphines 1 (R=alkyl or aryl) are well
known bidentate ligands in coordination chemistry
and catalysis [1,2]. In comparison with bis(phos-
phine)ligands of the type R2P(CH2)nPR2 with a flexible
alkyl backbone, ferrocenylbiphosphines show different
steric and electronic properties due to their rigid
backbone.
Additionally, the formation of bimetallic complexes
by coordination of the phosphine moiety and studies
concerning their structural and electronic properties
2. Results and discussion
For the preparation of symmetrically substituted 1,1%-
ferrocenylbiphosphines (1) the 1,1%-dilithiated fer-
rocene–TMEDA complex [4] is an excellent starting
material [5,6]. It is treated with two equivalents of
ClP(iPr)2 (2a) or (+)-ClP(men)2 (2b), respectively at
* Corresponding author. Fax: +49-7247-822244.
E-mail address: office@itc-cpv.fzk.de (E. Dinjus)
1 Also corresponding author. Present address: Universita¨t-GH
Siegen, Fachbereich 8, Organische Chemie II, Adolf-Reichwein-
Straße 2, 57068 Siegen, Germany.
0022-328X/00/$ - see front matter © 2000 Elsevier Science S.A. All rights reserved.
PII: S0022-328X(99)00670-1

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A.R. Elsagir et al. / Journal of Organometallic Chemistry 597 (2000) 139–145
Table 1
,
Selected bond lengths (A) and angles (°) for (disoppf)PdCl2 (3a)
Bond lengths
FeꢀCp(1) a
FeꢀP(1)
PdꢀCl(1)
PdꢀP(1)
1.633(3) P(1)ꢀC(1)
3.424(3) P(1)ꢀC(7)
2.3526(9) P(1)ꢀC(10)
1.809(3)
1.860(3)
1.860(3)
0.0119(3)
b
2.2941(9) dP
Bond angles
Cp(1)ꢀFeꢀCp(1)% 179.9(3) C(1)ꢀCp(1)ꢀCp(1)%ꢀC(1)% 32.5(3)
P(1)ꢀFeꢀP(1)%
Cl(1)ꢀPdꢀCl(1)%
P(1)%ꢀPdꢀP(1)
PdꢀPꢀC(7)
89.4(3) tilt-angle h
87.53(5) Cl(1)%ꢀPdꢀP(1)%
103.59(4) P(1)ꢀPdꢀCl(1)
114.9(2) C(7)ꢀPꢀC(10)
101.0(2) C(1)ꢀPꢀPd
3.7(3)
84.57(3)
84.57(3)
105.0(2)
119.82(10)
Fig. 1. Symmetrically substituted ferrocenylbiphospines: 1,1%-bis(di-
isopropylphosphino)ferrocene (disoppf, 1a) and 1,1%-bis(di(+)
menthylphosphino)ferrocene (dmenpf, 1b).
C(10)ꢀPꢀC(1)
a Cp(1) and Cp(1)% are the centroids of the C(1)ꢀC(5) and
C(1)%ꢀC(5)% rings.
b Deviation dp of the P atoms from the mean Cp plane.
2.2. Dichloro-1,1%-bis(diisopropylphosphino)-
ferrocene–palladium(II) (disoppf)PdCl2 (3a) [9]
Fig. 2. Reaction scheme for the synthesis of symmetrically substituted
1,1%-ferrocenyldiphosphines (1).
Dichloro - 1,1% - bis(diisopropylphosphino)ferrocene –
palladium(II) (disoppf)PdCl2 (3a) was prepared from
H2[PdCl4] with one equivalent of disoppf (1a) in
ethanol at room temperature and was isolated as red
crystals from the crude reaction mixture. It crystallises
in the orthorhombic space group Pnna. The elementary
cell contains four molecular units. The Pd atom has
approximately a square-planar coordination sphere.
The angle PꢀPdꢀP% (103.59(4)°; see Table 1, Fig. 4) is
significantly wider than in the complex (dppf)PdCl2·
CH2Cl2 (4) (97.98(4)°) [6]. The PꢀCl and PdꢀP distances
in 3a are in the same order of magnitude as in 4. The
conformation of the Cp rings in 3a is staggered due to
the coordination of the P atoms to the Pd centre. The
torsion angle C(1)ꢀCp(1)ꢀCp(1)%ꢀC(1)% is 32.5(3)°. In
contrast to the solid-state structure of the free ligand
−78°C to yield analytically pure oils of achiral disoppf
(1a) and chiral and optically pure (+)-dmenpf (1b)
(Fig. 2).
2.1. 1,1%-Bis-(diidopropylphosphino)ferrocene (1a)
1,1%-Bis(diisopropylphosphino)ferrocene (1a) is well-
known in the literature since 1985 [7]; the crystal struc-
ture was determined recently [8]. In accordance with its
solid-state structure, the 31P-CPMAS NMR spectrum
(Fig. 3(a)) shows two singlets due to the two different
types of phosphorus atoms in the molecule.
Fig. 3. Solid-state 31P-CPMAS NMR spectra of (a) disoppf (1a) at
25°C and wR=6 kHz and (b) (disoppf)PdCl2 (3a) at 25°C and wR=6
kHz; x-axis, ppm; (*) spinning side bands.
Fig. 4. ORTEP plot of (disoppf)PdCl2 (3a) with non-H atoms as 30%
thermal vibration ellipsoids.

A.R. Elsagir et al. / Journal of Organometallic Chemistry 597 (2000) 139–145
141
Table 2
disoppf (1a) [8], the P atoms in 3a are equivalent. This
,
Selected bond lengths (A) and angles (°) for (+)-dmenpf (1a)
is in accordance with the 31P-NMR spectrum of 3a in
solution as well as in the solid state. The 31P resonance
of the complex 3a in solution is shifted downfield with
Dl=66.0 ppm relative to 1a.
Bond lengths
FeꢀCp(1)
FeꢀP
1.656(3)
3.509(3)
−0.0137(3) PꢀC(16)
PꢀC(1)
PꢀC(6)
1.819(3)
1.875(3)
1.890(3)
a
dP
Corresponding downfield shifts are also found in the
1H spectrum for all resonances and in the 13C spectrum
for the carbon atoms of the Cp system. The solid-state
31P-NMR spectrum of the bimetallic complex shows
just one resonance at l=65.8 ppm (Fig. 3(b)). In
agreement with its X-ray crystal structure, the phos-
phorus atoms are chemically and magnetically equiva-
lent.
Bond angles
Cp(1)ꢀFeꢀCp(1)% 175.0(2)
C(1)ꢀPꢀC(6)
C(1)ꢀPꢀC(16)
C(6)ꢀPꢀC(16)
Tilt angle h
C(1)ꢀCp(1)ꢀCp(1)%ꢀC(1)%
C(2)ꢀC(1)ꢀP
64.6(2)
119.1(3)
135.4(3)
89.4(2)
104.4(2)
104.21(13) C(5)ꢀC(1)ꢀP
103.13(14) P(1)ꢀFeꢀP%
6.0(2)
a Deviation dp of the P atoms from the mean Cp plane.
,
The bond lengths FeꢀP (3.424(9) A) are slightly
,
shorter than in disoppf (1a) (FeꢀP 3.5161(1) A and
,
FeꢀP% 3.555(1) A). The tetrahedral angles CꢀPꢀC
179.3(1)°) [8]. This is probably caused by the steric
influence of the bulky menthyl substituents. Conse-
quently the CꢀPꢀC angles are enlarged. The distance
between the Fe atom and the centre Cp(1) of the
around the P atoms are broadened out. All other
distances and angles correspond to the values found
for the ligand disoppf (1a) [8].
,
Cp ring (1.656(2) A) is in the same order of magnitude
2.3. 1,1%-Bis(di-(+)-menthylphosphino)ferrocene
(dmenpf) (1b)
,
as in 1a (1.651(2) A). The PꢀC bond lengths are within
the range found for comparable compounds [13]. How-
ever, the distance between P and C(1) with (1.819(3)
The synthesis of 1b was recently described by Brun-
ner and Janura [10]. (+)-Menthylchloride was pre-
pared by reaction of (+)-menthol with the Lukas
reagent (ZnCl2–HCl) following a modification of the
published procedure [11]. The corresponding Grignard
derivative was reacted with PCl3 to yield (+)-chlorodi-
menthylphosphine. Further reaction with 1,1%-dilithio-
ferrocene–TMEDA complex results in formation of
1b.
Surprisingly, the treatment of (+)-dmenpf (1b) with
H2[PdCl4], following thus the same procedures for
disoppf (1a), did not result any bimetallic palladium–
dichloride complex. The low reactivity of 1b may be
explained by its specific structural properties, the lim-
ited rotation around the CpꢀFeꢀCp axis caused by the
bulky menthyl substituents. Therefore a physical close-
ness between the phosphorus atoms and the palladium
centre is not possible.
,
A) is smaller than to the carbon atoms C(6) and
C(16).
2.5. Pd-catalysed cooligomerisation of CO2 with
1,3-butadiene
The Pd(0)-catalysed cooligomerisation of CO2 and
1,3-butadiene to 2-ethyliden-6-hepten-5-olid (d-lactone)
is a promising way to use CO2 as a C1-building block
in organic chemistry [14] (Fig. 6). Here we report on
2.4. X-ray crystal structure analysis
1,1%-Bis(di-(+)-menthylphosphino)ferrocene
(1b)
crystallises from hexane in the orthorhombic chiral
space group P21212 with two molecules per elementary
cell. For more detailed information see Ref. [12]. The
molecule has a twofold axis on the Fe-atom, the con-
formation of the Cp-rings is synclinic eclipsed with a
torsion angle C(1)ꢀCp(1)ꢀC(1)%ꢀCp(1)% of 64.6(6)° (see
Table 2, Fig. 5). The P atoms are just slightly displaced
from the planes of the Cp rings. The Cp rings are not
exactly coplanar, the tilt angle is 6.0(2)° and the angle
Cp(1)ꢀFeꢀCp(1)% is 175.0(2)°. These values are signifi-
cantly smaller than in disoppf (1a) (Cp(1)ꢀFeꢀCp(1)%=
Fig. 5. ORTEP plot of 1,1%-bis(di-(+)-menthylphosphino)ferrocene
(1b) with non-H atoms as 30% thermal vibration ellipsoids.

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4. Experimental
4.1. General
Commercially available reagents were used without
Fig. 6. Pd-catalysed telomerisation of 1,3-butadiene with CO2.
further purification. All reactions were carried out using
standard Schlenk techniques. Solvents were dried by
standard methods and freshly distilled prior use.
the first results of the activity of the ferrocene-based
ligands in this reaction. A detailed study dealing with
this topic will be published separately (Table 3).
The values for selectivity and turnover number
(TON) differ drastically from phosphine to phosphine
and from Pd compound to Pd compound. As the main
difference especially between 1a and 1b is the bulkiness
of the alkyl groups attached to the phosphorus atoms,
steric reasons in this special case may apply.
The elucidation of further reasons is the object of
current work, especially in situ NMR and in situ IR
studies.
4.2. Crystallographic data collection and processing
For all structures data were collected on an Enraf–
Nonius DAD4 diffractometer in the ꢀ/2q scan mode
using graphite monochromated Mo–Ka radiation. The
intensities were corrected for Lorentz and polarisation
effects. A correction for absorption was done for
(disoppf)PdCl2 (3a). The reduction of data was done
with the program MOLEN [16], the structures were
solved with SHELXS-86 [17] and the structure refinement
was obtained with SHELXL-93 [18].
4.3. Solution NMR spectroscopy
3. Conclusions
NMR spectra were recorded on a Bruker AC 200
Symmetrically substituted ferrocenylphosphines can
be prepared easily from tertiary chlorophosphines in a
one-step synthesis. The symmetry of the structure can
be completely different in the free phosphine and the
corresponding metal complex. We showed that they are
promising components to form homogeneous as well as
heterogeneous catalysts with several transition metals.
We already realised the successful use of ferro-
cenylphosphines and their palladium complexes in tran-
sition-metal-catalysed C,C-bond formation reactions
with CO2 as C1-building block [15].
1
(operating at 200.13 Hz for H, 50.29 MHz for 13C or
81.00 MHz for 31P) or a Varian Unity Inova 400
1
(operating at 399.98 Hz for H, 100.59 Hz for 13C or
1
161.92 MHz for 31P) spectrometer. H and 13C shifts
are given in ppm downfield from internal TMS. 31P
chemical shifts are given in ppm downfield from exter-
nal 85% H3PO4.
4.4. Solid-state NMR spectroscopy
31P{1H}-CPMAS spectra were obtained at 161.92
MHz using the standard xpolar1 pulse sequence sup-
plied with the VNMR software from VARIAN. 31P
chemical shifts are given in ppm downfield from exter-
nal 85% H3PO4. Rotating frequencies wR are specified at
the particular spectra.
Table 3
Results of the Pd-catalysed cooligomerisation of CO2 with butadiene
Pd compound
Phosphane
Selectivity to d-lactone TON a
(%)
4.5. Gas chromatography
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(acac)2
Pd(acac)2
Pd(acac)2
(Cp)Pd(allyl)
(Cp)Pd(allyl)
(Cp)Pd(allyl)
1a
1b
63
71
20
70
0
3
7
65
9
0
80
78
13
73
0
2
2
81
3
0
For the quantitative determination of the d-lactone a
25 m CP-Sil 5 (100% dimethylsiloxane) column was
used in a Chrompack CP 9000 GC. (Separation condi-
tions: 180°C isotherm, 35 kPa, injector: 250°C, detector
(FID): 280°C, carrier gas: nitrogen, internal standard:
pentadecane.)
dppf b
1a
1b
dppf
1a
1b
dppf
1a
c
Pd2(dba)3
Pd2(dba)3
Pd2(dba)3
4.6. Further analytical methods
1b
dppf
60
0
60
0
IR spectroscopic data were recorded on a Perkin–
Elmer FT-IR 16-PC spectrometer. EI mass spectra were
measured on a Finnigan MAT SS-Q 710 (70 eV) spec-
trometer. Elemental analyses were performed using a
a TON, turnover number (mole product per mole Pd).
b dppf, 1,1%-bis(diphenylphosphino)ferrocene.
c dba, dibenzylidenacetone.

A.R. Elsagir et al. / Journal of Organometallic Chemistry 597 (2000) 139–145
143
LECO CHNS 932 analyser at the Laboratory of Or-
ganic Chemistry of the Friedrich-Schiller University
(Jena, Germany).
drochloric acid. The obtained solution was stirred at
50°C for 30 min and filtered over 5 cm of kieselgur. At
20°C, 26.2 mg (0.064 mmol) 1,1%-bis(diisopropylphos-
phino)ferrocene (disoppf, 1a), dissolved in 2 ml of
diethylether, were added and the mixture was stirred
for a further 10 min. At −35°C orange–red crystals
were formed, filtered and washed five times with a total
amount of 100 ml of water and then dried in vacuo.
Yield: 22.4 mg (0.038 mmol, 38%); m.p. 296°C
(decomposition).
4.7. Syntheses
4.7.1. Preparation of chlorodi-(+)-menthylphosphine
(2b)
Chlorodi-(+)-menthylphosphine (2b) was synthe-
sised according to the literature procedures starting
from (+)-menthol [11].
IR (KBr pellet, cm−1): 3905, 3082, 2963, 2926, 2968,
1459, 1166, 1039, 822, 653, 499.
MS m/z 596 (13%) [M+], 468 (10%), 418 (2%), 375
(39%), 333 (3%), 302 (13%), 259 (8%), 246 (17%), 217
(38%), 182 (19%), 139 (53%), 121 (17%), 97 (42%), 66
(25%), 41 (100%) [C3H5].
4.7.2. Preparation of 1,1%-dilithioferrocene–TMEDA
complex
1,1%-Dilithioferrocene–TMEDA complex was synthe-
sised according to the literature procedure [4] and iso-
lated by filtration as an orange pyrophoric powder.
1H-NMR [CDCl3]: l=1.19 (dd, 12H, (C-7)H3, (C-
3
3
10)H3, JHH=6.9 Hz, JPH=15.8 Hz); 1.60 (dd, 12H,
(C-8)H3, (C-11)H3; 3JHH=7.2 Hz; 3JPH=17.7 Hz);
3.00 (dsept, 4H, (C-6)H, (C-9)H, 3JHH=7.1 Hz,
2JPH=2.4 Hz); 4.48 (s, 4H, Cp system); 4.58 (s, 4H,
Cp system).
4.7.3. Preparation of 1,1%-bis(diisopropylphosphino)-
ferrocene (disoppf) (1a) [7,8]
To a vigorously stirred suspension of 12.8 g (70.8
mmol) 1,1%-dilithioferrocene–TMEDA complex [4] in
100 ml hexane 14.3 g (93.7 mmol) chlorodiisopropy-
lphosphine (2a) was added dropwise at −78°C. The
reaction mixture was stirred for further 30 min and
then warmed up slowly to 20°C. After hydrolysis with
15 ml water, the organic layer was separated, dried
with Na2SO4 and the solvent was removed in vacuo.
The obtained orange oil was analytically pure. Within
a few hours at 5°C orange crystals of disoppf (1a) were
formed (11.4 g, 27.2 mmol, 58%) m.p. 48–51°C.
IR (KBr pellet, cm−1): 2968, 2947, 2925, 2895, 2861,
1463, 1379, 1360, 1156, 1029, 806, 503, 488.
13C{1H}-NMR [C6D6]: l=19.2 (s, 4C, CH3, C-7,
3
C-10); 20.2 (d, 4C, CH3, C-8, C-11, JCP=2 Hz); 28.5
(m, 4C, CH, C-6, C-9); 72.5 (s, 4C, Cp system); 74,2 (s,
6C, Cp system).
31P{1H}-NMR [C6D6]: l=65.8 (s). Anal. Calc. (%):
C, 44.4; H, 6.1; Cl, 11.9; Found: C, 44.1; H, 5.8; Cl,
11.7.
Crystal data for 3a: C22H36Cl2FeP2Pd, Mr=595.60 g
mol−1, brown prism, size 0.35×0.32×0.28 mm3, or-
thorhombic, space group Pnna, a=16.058(1), b=
3
,
,
19.985(1), c=8.883(1) A, V=2422.8(3) A , T=
−90°C, Z=4, zcalc. =1.633 g cm−3, v(Mo–Ka)=
17.01 cm−1, psi-scan, transmin: 0.228, transmax: 0.273,
F(000)=1216, 4247 reflections in h(0/20), k(−16/21),
l(−11/8), measured in the range 2.545[526.31°,
2466 independent reflections, 1801 reflections with
Fo\4|(Fo), 200 parameters, 0 restraints, R1obs=0.030,
wR2obs=0.067, R1all=0.058, wRa2ll=0.079, Goodness-
MS m/z 418 (26%) [M+], 376 (25%), 375 (100%)
[M+ꢀC3H7], 333 (12%), 299 (3%), 289 (12%), 257
(10%), 246 (25%), 217 (15%), 186 (13%), 152 (14%),
121 (21%), 97 (4%), 56 (9%), 43 (19%).
1H-NMR [C6D6]: l=1.09 (dd, 12H, (C-7)H3 (C-
10)H3, 3JHH=7.0 Hz; 3JPH=3.2 Hz); 1.16 (d, 12H,
(C-8)H3, (C-11)H3, 3JHH=7.0 Hz); 1.90 (dsept, 4H,
(C-6)H, (C-9)H, 3JHH=7.0 Hz, 2JPH=1.6 Hz); 4.18
(m, 4H, (C-2)H, (C-5)H); 4.27 (m, 4H, (C-3)H, (C-
4)H).
of-fit=1.071, largest difference peak and hole: 0.504/
−3
,
−0.395 e A
.
4.7.5. Preparation of
13C{1H}-NMR [C6D6]: l=20.1 (d, 4C, CH3, C-7,
1,1%-bis(di-(+)-menthylphosphino)ferrocene (1b)
1,1%-Dilithioferrocene–TMEDA complex (3.2 g, 10.2
mmol) [4] was suspended in 50 ml hexane and stirred
vigorously. A solution of 7.0 g (20.3 mmol) chlorodi-
(+)-menthylphosphine (2b) in 50 ml hexane was
added dropwise at −78°C. The reaction mixture was
stirred for 1 h and then allowed to reach 20°C. The
orange-coloured reaction mixture was quenched with
20 ml of water. The aqueous layer was separated and
washed twice with 20 ml of hexane. The combined
organic layers were dried with Na2SO4, filtered and the
solvent was removed in vacuo. The obtained orange oil
2
C-10, JCP=11 Hz); 20.6 (s, 4C, CH3, C-8, C-11); 23.7
1
(d, 4C, CH, C-6, C-9, JCP=14 Hz); 71.8 (s, 4C, CH,
2
C-3, C-4), 72.4 (d, 4C, CH, C-2, C-5, JCP=11 Hz);
1
77.4 (d, 2C, Cq, C-1, JCP=21 Hz).
31P{1H}-NMR [C6D6]: l= −0.2 (s). Anal. Calc.
(%): C, 63.2; H, 8.9; Found: C, 62.6; H, 8.3.
4.7.4. Preparation of dichloro-1,1%-
bis(diisopropylphosphino)ferrocene–palladium(II) (3a)
PdCl2 (17.9 mg, 0.101 mmol) was suspended in 2 ml
of ethanol and treated with 2 ml of concentrated hy-

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was dissolved in 10 ml hexane. Within a few days
orange crystals of 1b were formed at 25°C (6.4 g, 78%);
m.p. 221–223°C; [a]2D0= +199.3 (c=2, CHCl3).
IR (KBr pellet, cm−1): 1638, 1384, 1366, 1191, 1181,
1155, 1032, 819.
(100 mmol). The reaction was started by heating the
mixture to 70°C for 15 h. After cooling down the
reactor to 25°C the reaction mixture was filtered over 5
cm of alumina to remove the catalyst and analysed by
GC.
MS m/z 804 (6%) [M++1], 802 (29%) [M+−1],
663 (9%), 525 (18%), 493 (37%), 401 (10%), 353 (8%),
249 (65%), 217 (39%), 186 (64%), 137 (8%), 95 (25%),
83 (100%) [M+ꢀCH2, ꢀC3H7, ꢀCpPMen2, ꢀCpPMen,
ꢀFe], 55 (56%), 43 (26%).
References
[1] A. Togni, T. Hayashi (Eds.), Ferrocenes, VCH Verlags-
gesellschaft, Weinheim, Germany, 1995.
[2] A. Togni, Chimia 50 (1996) 86.
1H-NMR [C6D6]: l=0.85 (dd, 12H, (C-13)H3, (C-
3
3
5
23)H3, JHH=6.4 Hz, JHH=7.0 Hz, JPH=16.2 Hz);
1.07 (dd, 12H, (C-14)H3, (C-24)H3, 3JHH=6.2 Hz,
3JHH=6.8 Hz, 5JPH=16.0 Hz); 1.13 (d, 12H, (C-
[3] (a) B. Corain, B. Longato, G. Favero, D. Ajo`, G. Pilloni, U.
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lics 4 (1985) 2196.
3
15)H3, (C-25)H3, JHH=7.0 Hz); 1.29–1.86 (m, 24H);
2.15 (m, 3H, CH); 2.41 (d, 3H, CH2, JPH=12.7 Hz);
3.13–3.23 (m, 6H, CH); 4.32–4.39 (m, 8H, Cp system).
13C{1H}-NMR [C6D6]: l=15.9 (s, 2C, CH3, C-13);
16.3 (d, 2C, C-23); 21.9 (d, 2C, C-14); 22.3 (d, 2C,
C-24); 23.0 (s, 4C, CH3, C-15, C-25); 26.2 (m, 4C,
CH2, JCP=9 Hz); 27.2 (dd, 4C, CH, JCP=26 Hz);
34.1 (s, 2C, CH); 35.5 (s, 4C, CH2); 38.5 (d, 4C, CH,
J
CP=65 Hz); 39.8 (s, 2C, CH2); 41.1 (s, 2C, CH2); 45.3
[5] (a) J.J. Bishop, A. Davison, M.L. Katcher, D.W. Lichtenberg,
R.E. Merrill, J.C. Smart, J. Organomet. Chem. 27 (1971) 241. (b)
I.R. Butler, W.R. Cullen, T.-J. Kim, Synth. React. Inorg. Met.-
Org. Chem. 15 (1985) 109. (c) D. Seyferth, H.P. Withers, Jr., J.
Organomet. Chem. 185 (1980) C1. (d) A.W. Rudie, D.W. Licht-
enberg, M.L. Katcher, A. Davison, Inorg. Chem. 17 (1978) 2859.
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43. (f) G.E. Herberich, S. Moss, Chem. Ber. 128 (1995) 689.
[6] I.R. Butler, W.R. Cullen, T.-J. Kim, S.J. Rettig, J. Trotter,
Organometallics 4 (1980) 972.
[7] I.R. Butler, W.R. Cullen, T.-J. Kim, Synth. React. Inorg. Met.-
Org. Chem. 15 (1985) 109.
[8] R.B. Bedford, P.A. Chaloner, E. Dinjus, R. Fornika, H. Go¨rls,
P.B. Hitchcock, W. Leitner, J. Chem. Soc. Dalton Trans. ac-
cepted for publication.
(d, 2C, CH, JCP=15 Hz); 47.5 (d, 2C, CH, JCP=22
Hz); 70.0 (s, 2C, CH, C-3, C-3%); 71.2 (s, 2C, CH, C-4,
C-4%); 72.2 (m, 2C, CH, C-2%, C-5); 77.1 (d, 2C, CH,
2
C-2, C-5%, JCP=29 Hz), 78.4 (d, 2C, Cq, C-1, C-1%,
1JCp=20 Hz).
31P{1H}-NMR [C6D6]: l= −25.2 (s). Anal.
Calc.(%): C, 74.8; H, 10.5; P, 7.7; Found: C, 74.7; H,
9.8; P, 7.3.
Crystal data for 1b: C50H84FeP2, Mr=802.96 g
mol−1, orange prism, size 0.40×0.40×0.36 mm3, or-
thorhombic, space group P21212, a=9.671(2), b=
26.913(5), c=9.075(2) A, V=2362.0(8) A , T=
−90°C, Z=2, zcalc. =1.129 g cm−3, v(Mo–Ka)=
4.18 cm−1, F(000)=880, 3052 reflections in h(−12/0),
k(−34/0), l(0/11), measured in the range 2.375[5
27.42°, 3052 independent reflections, 2592 reflections
3
,
,
[9] Recently a different synthetic route for 3a was published (A.L.
Boyes, I.R. Butler, S.C. Quayle, Tetrahedron Lett. 39 (1998)
7763). Given the lack of structural information (e.g. X-ray cell
parameters, solid state NMR spectra), we decided to go further
into the structural elucidation of 3a.
[10] H. Brunner, M. Janura, Synthesis (1998) 45.
with Fo\4|(Fo), 240 parameters, 0 restraints, R1obs
=
[11] (a) J.G. Smith, G.F. Wright, J. Org. Chem. 17 (1952) 1116. (b)
H.W. Krause, A. Kinting, J. Prakt. Chem. 322 (1980) 485.
[12] Further details of the crystal structure investigations are available
on request from the director of the Cambridge Crystallographic
Data Centre, 12 Union Road, GB Cambridge CB2 1 EZ, on
quoting the depository number CCSD-135011 (1b) and CCSD-
135012 (3a), the names of the authors, and the journal citation.
[13] F.H. Allen, O. Kennard, D.G. Watson, L. Brammer, A. Guy
Orpen, R. Taylor, J. Chem. Soc. Perkin Trans. II (1987) S1.
[14] (a) Y. Sasaki, Y. Inoue, H. Hashimoto, J. Chem. Soc. Chem.
Commun. (1976) 605. (b) Y. Inoue, Y. Sasaki, H. Hashimoto,
Bull. Chem. Soc. Jpn. 51 (1978) 2375. (c) A. Behr, Carbon
Dioxide Activation by Metal Complexes, VCH Weinheim, 1988.
(d) S. Pitter, E. Dinjus, B. Jung, H. Goerls, Z. Naturforsch. 51B
(1996) 934.
0.033, wR2obs=0.086,
Goodness-of-fit=1.190,
R
1all=0.053, wR2all=0.143,
Flack-parameter 0.00(3),
largest difference peak and hole: 0.374/−0.195
e A
−3
,
.
4.8. Standard procedure for catalytic runs
Under an atmosphere of argon a 160 ml stainless
steel autoclave was charged with the phosphine (0.048
mmol) and the Pd compound (0.048 mmol). A total of
30 ml acetonitrile was added, the reactor was closed
and cooled down to −30°C. 1,3-butadiene (70.3 mmol,
3.8 g) was transferred into the autoclave from a lecture
bottle with a Teflon tube (for a short period of time
Teflon is resistant to butadiene). After warming up to
25°C the autoclave was pressurised with 8 atm of CO2
[15] (a) A.R. Elsagir, Einsatz neuer Katalysatorsysteme in der Palla-
dium-katalysierten Cooligomerisation von 1,3-Butadien und
Kohlendioxid, PhD thesis, Jena, 1997, Shaker Verlag, Aachen,
Germany, 1998. (b) M. Nauck, Zum Einfluß chiraler Phosphan-
liganden und der Katalysatorzusammensetzung auf die

A.R. Elsagir et al. / Journal of Organometallic Chemistry 597 (2000) 139–145
145
Cooligomerisierung von 1,3-Butadien und CO2, PhD thesis,
Jena, 1998, Shaker Verlag, Aachen, Germany, 1999.
[17] G.M. Sheldrick, SHELXS-86, Program for the Solution of Crystal
Structures, University of Go¨ttingen, Germany, 1990.
[16] MOLEN
,
Interactive Structure Determination, Enraf–Nonius,
[18] G.M. Sheldrick, SHELXL-93, Program for Crystal Structures
Determination, University of Go¨ttingen, Germany, 1993.
Delft, Netherlands, 1990.
.