Optically active transition-metal complexes: Part 124. Chiral 1-phospha[1]ferrocenophanes and 1,12-diphospha[1.1]ferrocenophanes - Synthesis, characterization and ring-opening polymerization

Article abstract of DOI:10.1016/S0022-328X(00)00064-4

The phosphorus(III)-bridged [1]ferrocenophanes 1,1′-ferrocenediylphenylphosphine (1), (-)-1,1′-ferrocenediylmenthylphosphine (2) and (-)-bornyl-1,1′-ferrocenediylphosphine (3) have been synthesized via the reaction of 1,1′-dilithioferrocene (TMEDA adduct)

Full text of DOI:10.1016/S0022-328X(00)00064-4

www.elsevier.nl/locate/jorganchem
Journal of Organometallic Chemistry 601 (2000) 211–219
Optically active transition-metal complexes
Part 124. Chiral 1-phospha[1]ferrocenophanes and
1,12-diphospha[1.1]ferrocenophanes — synthesis, characterization
and ring-opening polymerizationꢀ
Henri Brunner * , Ju¨rgen Klankermayer, Manfred Zabel 1
Institut fu¨r Anorganische Chemie, Uni6ersita¨t Regensburg, D-93040 Regensburg, Germany
Received 26 November 1999
Abstract
The phosphorus(III)-bridged [1]ferrocenophanes 1,1%-ferrocenediylphenylphosphine (1), (−)-1,1%-ferrocenediylmenthylphos-
phine (2) and (−)-bornyl-1,1%-ferrocenediylphosphine (3) have been synthesized via the reaction of 1,1%-dilithioferrocene (TMEDA
adduct) and Cl2PR (R=Ph, Men, Bor). Compounds 1 and 2 have been used as ligands in the preparation of the complexes
Cp*Mn(CO)2[Fe(h5-C5H4)2PPh] (4) and (−)-trans-PdCl2[Fe(h5-C5H4)2PMen]2 (5). The new compounds 2–5 were characterized
by multinuclear NMR, by MS, and 2, 4 and 5 by single-crystal X-ray diffraction. Remarkably, the cyclic dimer anti-exo,exo-1,12-
dimenthyl-1,12-diphospha[1.1]ferrocenophane (6) could be isolated and structurally characterized. The thermal ring-opening
polymerization of 1, 2 and 3 yielded the poly(ferrocenediylphosphines) 7, 8 and 9. Compounds 2 and 8 were used as chiral ligands
in the Rh-catalyzed diastereoselective hydrogenation of folic acid. © 2000 Elsevier Science S.A. All rights reserved.
Keywords: [1]Ferrocenophane; [1.1]Ferrocenophane; Ring-opening polymerization (ROP); Phosphorus; Chirality
1. Introduction
meric ligands for application in enantioselective cataly-
sis [9].
Since their discovery in 1975 [2] [1]ferrocenophanes
have attracted attention because of their interesting
structures and reactivity [3]. The synthetic potential due
to the strained bonding situation in such compounds
has been exploited in ring-opening polymerizations
(ROPs), which can be conducted under thermal [4,5],
anionic [6] or coordination-catalyzed [7] conditions.
Although 1-organo-1-phospha[1]ferrocenophanes have
been known since 1980 [8], no chiral organic substituent
has been used at the phosphorus atom up to now. We
prepared 1-phospha[1]ferrocenophanes with chiral
substituents at the phosphorus atom and we poly-
merized them under thermal conditions to obtain poly-
2. Results and discussion
2.1. Synthesis of (−)-1,1%-ferrocenediylmenthyl-
phosphine (2) and (−)-bornyl-1,1%-ferrocenediyl-
phosphine (3)
Phosphorus-bridged [1]ferrocenophanes, first re-
ported in the 1980s [8,10], were prepared by the reac-
tion of 1,1%-dilithioferrocene (TMEDA adduct) with
t
dichloroorganophosphines Cl2PR (R=Me, Bu, Ph) in
non-polar solvents such as hexanes. According to the
literature [10], 1,1%-ferrocenediylphenylphosphine 1 was
synthesized in the reaction of Cl2PPh with 1,1%-dilithio-
ferrocene (TMEDA adduct) in hexanes (Scheme 1).
Similarly, the reaction of 1,1%-dilithioferrocene with (−)-
dichloromenthylphosphine in hexanes was expected to
result in the formation of 1,1%-ferrocenediylmen-
thylphosphine 2. Unfortunately, this reaction did not
ꢀ For Part 123, see Ref. [1].
* Corresponding author. Tel.: +49-941-9434441; fax: +49-941-
9434439.
E-mail address: henri.brunner@chemie.uni-regensburg.de (H. Brun-
ner)
1 X-ray structure analyses.
0022-328X/00/$ - see front matter © 2000 Elsevier Science S.A. All rights reserved.
PII: S0022-328X(00)00064-4

212
H. Brunner et al. / Journal of Organometallic Chemistry 601 (2000) 211–219
work. However, (−)-dichloromenthylphosphine could
be converted into the desired [1]ferrocenophane 2 ex-
changing hexanes by 1,2-dimethoxyethane (DME)
Fig. 2. Assignments of angles in [1]ferrocenophanes.
(Scheme 1). The preparation of (−)-bornyl-1,1%-fer-
rocenediylphosphine (3) succeeded in hexanes (Scheme
1), but as the diastereomeric purity of the (−)-
bornyldichlorophosphine used was 90% de, 3 could
only be isolated with a diastereomeric excess of 90%.
Compounds 2 and 3 are red solids, which are mod-
erately air sensitive. Both [1]ferrocenophanes are sta-
ble under an inert atmosphere in hydrocarbon
solvents, but slowly decompose in solvents such as
ethanol or THF.
1
The H-NMR spectra of 2 and 3 contain eight res-
onances for the eight protons of the diastereotopic
Cp rings. In the 13C-NMR spectra of 2 and 3 the
most striking feature is the high-field shift of the ipso-
carbon atoms of the [1]ferrocenophane (lC=20.1/22.9
ppm for 2 and lC=16.9/22.1 ppm for 3). The
diastereomeric excess of compound 3 was determined
from the intensities of the two 31P-NMR signals at
−3.0 and 3.9 ppm.
Scheme 1.
2.2. X-ray structural analysis of
(−)-Fe(p5-C5H4)2PMen (2)
Dark red crystal of 2 suitable for a single-crystal
X-ray diffraction study were obtained from hexanes
at −35°C. The distorted sandwich structure of 2 is
shown in Fig. 1. Selected bond lengths and angles are
given in Table 1. The angles h, i, l and q are
defined in Fig. 2.
The molecular structure of 2 reveals a tilt angle h
between the planes of the Cp rings of 27.43°. This Cp
ring tilting in 2 is accompanied by a RC1ꢀFeꢀRC2
(RC=ring centroid) angle l of 159.62°, and a 29.1
pm displacement of the iron atom from the intersec-
tion of the two ring centroids. Additional structural
distorsions include angles i of 31.27 and 31.58° be-
tween the Cp ring planes and the exocyclic CꢀP
bonds. The C(1)ꢀPꢀC(6) angle q of 89.80(10)° is quite
similar to the angles found in other 1-phos-
pha[1]ferrocenophanes (Table 2) [11,12]. Compared
Fig. 1. Molecular structure of 2.
Table 1
Selected bond lengths (pm) and angles (°) in 2
Bond lengths
Fe···P
281.31(7)
199.7(2)
202.2(2)
208.5(2)
208.9(2)
203.2(2)
164.26
PꢀC(11)
FeꢀC(6)
FeꢀC(7)
FeꢀC(8)
FeꢀC(9)
FeꢀC(10)
Fe···RC2
185.8(2)
199.2(2)
201.5(2)
209.0(2)
209.7(2)
203.8(2)
164.27
FeꢀC(1)
FeꢀC(2)
FeꢀC(3)
FeꢀC(4)
FeꢀC(5)
Fe···RC1
with
Fe(h5-C5H4)2PPh
(1)
[11]
and
Fe(h5-
C5H4)2PNiPr2 [12], the Fe···P distance in 2 is slightly
longer (281.31(7) vs. 277.4(1) and 280.2(1) pm, Table
2). The distances Fe···RC1 (164.26 pm) and Fe···RC2
(164.27 pm) are very close to the value of 166 pm in
ferrocene [13]. Both Cp rings are planar and they are
arranged in an ecliptic position.
Bond angles
C(1)ꢀPꢀC(11)
C(1)ꢀFeꢀC(6)
C(2)ꢀFeꢀC(7)
C(3)ꢀFeꢀC(8)
103.48(11)
82.65(9)
97.04(10)
132.35(11)
C(6)ꢀPꢀC(11)
C(4)ꢀFeꢀC(9)
C(5)ꢀFeꢀC(10)
104.18(10)
125.36(9)
99.80(12)

H. Brunner et al. / Journal of Organometallic Chemistry 601 (2000) 211–219
213
Table 3
2.3. Synthesis and X-ray structural analysis of
deri6ati6es of 1 and 2
Selected bond lengths (pm) and angles (°) in 4
PꢀC(1)
PꢀC(6)
PꢀC(11)
P···Fe
PꢀMn
FeꢀC(1)
FeꢀC(6)
185.85(18)
184.67(19)
182.89(18)
276.74(5)
221.13(5)
199.00(19)
199.14(18)
C(27)ꢀO(1)
C(28)ꢀO(2)
MnꢀC(27)
MnꢀC(28)
Fe···RC1
116.0(3)
Compounds 1 and 2 can serve as tertiary phosphine
ligands in transition-metal complexes. A dinuclear com-
plex was prepared by treating Cp*Mn(CO)2THF with
one equivalent of 1 to give Cp*Mn(CO)2[Fe(h5-
C5H4)2PPh] (4) (Scheme 2). The 31P-NMR spectrum of
4 shows the expected downfield shift of the phosphorus
115.9(3)
177.1(2)
177.2(2)
164.16
164.02
177.10
Fe···RC2
Mn···RC3
h
26.80(13)
C(1)ꢀPꢀC(11) 103.59(8)
i
32.66(11)/32.59(12) C(6)ꢀPꢀC(11) 102.30(8)
160.25
91.80(8)
96.30(6)
87.69(6)
92.40(9)
l
C(1)ꢀPꢀMn
C(6)ꢀPꢀMn
C(11)ꢀPꢀMn
121.91(6)
117.62(6)
115.62(6)
Table 2
Characteristic bond lengths (pm) and angles (°) a in 1-phos-
pha[1]ferrocenophanes, Fe(h5-C5H4)2PR
q
PꢀMnꢀC(27)
PꢀMnꢀC(28)
C(27)ꢀMnꢀC(28)
R=tBu
R=Ph
R=NiPr2 R=Men 2
[11]
[11]
[12]
This study
Fe···P
276.3(1)
198.3(3)
197.8(4)
263.3(5)
185.4(3)
187.0(4)
277.4(1)
198.2(4)
197.9(4)
263.2(6)
184.9(5)
185.0(5)
280.2(1)
197.7(2)
198.2(6)
261.0(2)
187.4(2)
185.5(2)
281.31(7)
199.3(2)
199.2(2)
263.4(7)
186.3(2)
186.9(2)
resonance from that of the free ligand at lP=9.3–109.7
ppm. In the IR spectrum of 4 two peaks in the carbonyl
region at 1922 and 1855 cm−1 are detected. For
Cp*Mn(CO)2PPh3 the absorptions occur at 1915 and
1855 cm−1 [14], confirming the similarity of 1 and PPh3
as ligands.
FeꢀC(1)
FeꢀC(6)
C(1)···C(6)
PꢀC(1)
PꢀC(6)
h
27.1
26.9
27.8
27.43
i (average)
l
32.8
159.8
90.5(2)
32.3
159.8
90.7(2)
41.2(2)
157.1
88.8(1)
31.4
159.62
89.80(10)
Orange–brown single crystals of 4 were obtained
from hexanes at 5°C. The molecular structure of 4 is
shown in Fig. 3. Selected bond lengths and angles are
listed in Table 3.
q
a See Fig. 2.
The half-sandwich complex 4 adopts the expected
piano stool geometry and the distorted structure of 1 is
retained in the complex. Thus, the tilt angle h between
the Cp planes (26.80(13) vs. 26.90°) and the Fe···P
distance (276.74(5) vs. 277.4(1) pm) are almost the same
as for the free ligand 1 [11]. The octahedral geometry of
4 shows up in the angles between the monodentate
ligands bonded to the Mn atom, which are around 90°
(Table 3).
Scheme 2.
A trinuclear heterobimetallic complex was prepared
by treating Pd(cod)Cl2 with two equivalents of 2 to give
(−)-trans-PdCl2[Fe(h5-C5H4)2PMen]2 (5) (Scheme 3).
In analogy to ligand 2, complex 5 exhibits an
1
AA%BB%CC%DD% pattern for the Cp protons in the H-
NMR spectrum. The 31P-NMR chemical shift of lP=
49.2 ppm for 5 is 39.9 ppm downfield compared with 2,
consistent with a coordination of the phosphine 2 to the
metal centre.
An X-ray crystal structure determination was carried
out for 5. The molecular structure of 5 is shown in Fig.
4. Selected bond lengths and angles are given in Table
4.
Compound 5 consists of a square-planar trans-
dichlorodiphosphine-palladium centre, as is usually ob-
served in such complexes [15]. In the C2 symmetrical
complex, the two menthyl groups and the two fer-
rocenediyl moieties point into the same direction. The
tetrahedral geometry of the phosphorus atom is dis-
tored by ring strain such that the angle q between the
Fig. 3. Molecular structure of 4.

214
H. Brunner et al. / Journal of Organometallic Chemistry 601 (2000) 211–219
Scheme 3.
two ipso-carbon atoms is reduced to 92.43(17)°, com-
pared with 89.80(10)° for the free ligand 2, whereas the
angles between the first menthyl carbon atom and the
ipso-carbon atoms are 109.89(18) and 106.07(17)°.
There is only a slight influence of the coordinating Pd
atom on the strained [1]ferrocenophane structure, as
the values obtained for h (27.62 vs. 27.43°) and the
Fe···P distances (274.15(11) vs. 281.31(7) pm) in 5 and
the free ligand 2 are quite similar.
C(1)ꢀP(1)ꢀC(6) angle is widened to 107.51(19)°. This
widening relieves the repulsion of the inner a protons
together with the twisting of the ferrocene groups fc-1
and fc-2. The Fe atoms are located symmetrically be-
tween the rings with FeꢀC distances between 202.7 and
206.7 pm, resulting in a Fe···Fe distance of 504.3(15)
pm. This Fe···Fe distance is longer than in the CH2-
bridged [1.1]ferrocenophane (481.6(2) pm), but slightly
shorter than in the SiMe2 bridged species (517.1(9) pm)
[18,19].
2.4. Synthesis and X-ray structure analysis of
anti-exo,exo-1,12-dimenthyl-1,12-diphospha[1.1]-
ferrocenophane (6)
Until we started the present work, the only struc-
turally characterized symmetrical [1.1]ferrocenophanes
had bridging atoms from Group 14 (C [16,17], Si [18],
Sn [19]) of the Periodic Table. We prepared the first
phosphorus-bridged [1.1]ferrocenophane by the reac-
tion of 1,1%-dilithioferrocene with (−)-dichloromen-
thylphosphine in hexanes at −40°C (Scheme 4). In
addition to the dimer 6, trimers, tetramers and pen-
tamers were found as shown by field desorption mass
spectrometry in CH2Cl2. The isolation of 6 from the
reaction mixture was achieved by medium-pressure liq-
uid chromatography (MLC).
Crystals of the cyclic dimer 6, suitable for a single-
crystal X-ray diffraction study, were obtained from
CH2Cl2–hexanes at −35°C. Fig. 5 shows the molecu-
lar structure of compound 6 and Table 5 lists selected
bond lengths and angles.
Fig. 4. Molecular structure of 5. Hydrogen atoms are omitted for
clarity.
The molecular structure of 6 consists of two fer-
rocenediyl units linked in a [1.1]-manner through two
PMen bridges and exhibits a chair-like anti-conforma-
tion. Remarkably, the tilt angles are opposite in direc-
tion to those in [1]ferrocenophanes. Thus, for 6 ring
tilts of −2.12° (Cp(1) and Cp(3)) and −6.11° (Cp(2)
and Cp(4)) were observed. The Cp ligands of the
ferrocene parts are staggered by 9.0° (Cp(1) and
Cp(3)) and 25.2° (Cp(2) and Cp(4)) (Fig. 6). The
phosphorus-bridged Cp rings are twisted by 13.1°
(Cp(1) and Cp(2)) and 13.8° (Cp(3) and Cp(4)). Excep-
tional are the bond angles around the P atoms.
Whereas the C(1)ꢀP(1)ꢀC(11) angle is 97.75(18)° and
the C(6)ꢀP(1)ꢀC(11) angle is 100.45(17)°, the
Table 4
Selected bond lengths (pm) and angles (°) in 5
PdꢀCl(1)
PdꢀP(1)
P(1)ꢀC(6)
P(1)ꢀC(1)
P(1)ꢀC(11)
Fe(1)···P(1)
229.80(7)
232.53(8)
182.5(4)
181.9(4)
183.8(5)
274.15(11)
Fe(1)ꢀC(1)
Fe(1)ꢀC(6)
RC1···RC2
Fe(1)···RC1
Fe(1)···RC2
198.1(4)
198.2(0)
321.64
163.36
163.37
h
i
l
q
27.6(2)
C(1)ꢀP(1)ꢀC(11) 106.07(17)
32.3(5)/32.5(2) C(6)ꢀP(1)ꢀC(11) 109.89(18)
159.77
92.43(17)
C(11)ꢀP(1)ꢀPd
P(1)ꢀPdꢀCl(1)
P(1)ꢀPdꢀCl(1a)
112.33(12)
89.07(3)
91.38(3)
Cl(1)ꢀPdꢀCl(1a) 174.32(5)
P(1)ꢀPdꢀP(1a) 170.88(5)

H. Brunner et al. / Journal of Organometallic Chemistry 601 (2000) 211–219
215
Scheme 4.
2.5. Ring-opening polymerization of 1, 2 and 3
in which (−)-BPPM gives 98% hydrogenation and
36.1–42.6% de of the (6S,S)-isomer of tetrahydrofolic
Since 2 and 3 have highly strained structures, thermal
ROP was expected to result in the formation of the
chiral poly(ferrocenediylphosphines) 8 and 9. Differen-
tial scanning calorimetry (DSC) of 2 showed a sharp
endothermic peak due to melting at 143°C and a broad
exothermic peak at an onset temperature of 191°C due
to ring-opening (Fig. 7). For 3 the endothermic melting
peak was observed at 102°C and the onset temperature
for the polymerization was 183°C (Scheme 5). An esti-
mation of the enthalpy for the ROP process was made
on the basis of the integration of the exothermic peak
and was found to be ca. 83 kJ mol−1 for 2 and 81 kJ
mol−1 for 3. By comparison, the enthalpy of polymer-
ization for 1 had been found to be 68 (95) kJ mol−1
[20] with an onset temperature of 117°C. Consequently,
the bulkier chiral groups have a slight effect on the
enthalpy, but cause an appreciable increase of the onset
temperatures of the polymerization.
acid [21]. With the [1]ferrocenophane ligand
2
diastereomeric excesses of 20.0 and 22.5% and hydro-
genation yields of 28 and 20% were achieved. In con-
trast, the use of the polymeric ligand 8 gave a high
hydrogenation yield (94 and 91%), but only a low
diastereomeric excess (2.1 and 2.6%).
An attempt to polymerize 2 and 3 on a preparative
scale was carried out by heating the [1]ferrocenophanes
at ca. 190–195°C for 2 h. After purification, analysis of
the product by NMR was consistent with a ring-opened
structure. In particular, the 31P-NMR spectrum of 8
showed only one broad resonance at lP= −29.3 ppm
with no sign of any residual monomer (lP=9.3 ppm).
This upfield shift agrees with the 31P-NMR data re-
Fig. 5. Molecular structure of 6. Hydrogen atoms are omitted for
clarity.
Table 5
Selected bond lengths (pm) and angles (°) in 6
Fe(1)···Fe(2)
C(1)ꢀP(1)
C(6)ꢀP(1)
C(11)ꢀP(1)
Fe(1)ꢀRC1
Fe(1)ꢀRC3
504.3(15)
182.1(4)
182.1(4)
189.7(4)
164.31(2)
164.70(2)
P(1)···P(2)
C(21)ꢀP(2)
C(26)ꢀP(2)
C(31)ꢀP(2)
Fe(2)ꢀRC2
Fe(2)ꢀRC4
486.6(2)
182.1(4)
183.0(4)
188.2(4)
165.53(2)
165.89(2)
1
ported for 7 in the literature [5]. The H-NMR spec-
trum contained only broad resonances with no signals
of the monomer left. In addition, field desorption mass
spectrometry of 8 and 9 in CH2Cl2 provided evidence
for the expected structures showing ions of oligo(fer-
rocenediylphosphines) of up to eight repeating units.
Fe(1)ꢀCCp (range) 202.7–205.3
Fe(2)ꢀCCp (range) 203.3–206.7
C(1)ꢀP(1)ꢀC(11)
C(6)ꢀP(1)ꢀC(11)
C(1)ꢀP(1)ꢀC(6)
RC1ꢀFe(1)ꢀRC3
97.75(18) C(21)ꢀP(2)ꢀC(31)
100.45(17) C(26)ꢀP(2)ꢀC(31)
107.51(19) C(21)ꢀP(2)ꢀC(26)
98.09(17)
98.95(16)
107.57(18)
174.91
2.6. Catalytic results
179.02
RC2ꢀFe(2)ꢀRC4
Rhodium complexes, generated in situ from
[Rh(cod)Cl]2 and the ligands 2 and 8, were used as
catalysts in the asymmetric hydrogenation of folic acid,
ÚCp(1)ꢀCp(3)
ÚCp(1)ꢀCp(2)
2.12
13.84
ÚCp(2)ꢀCp(4)
ÚCp(3)ꢀCp(4)
6.11
13.08

216
H. Brunner et al. / Journal of Organometallic Chemistry 601 (2000) 211–219
fragment, Bor for the (1S,2R)-bornyl fragment and fc
for the ferrocenediyl fragment.
Melting points: SMP-20 (Bu¨chi), not corrected. Vi-
brational spectra: Beckman spectrometer IR 4240 (KBr
pellets). MS: MAT 311 A (electron impact) and MAT
95 (field desorption), both Finnigan. Optical rotations:
Perkin–Elmer 241 polarimeter at room temperature
(r.t.). DSC: Mettler–Toledo DSC30 differential scan-
ning calorimeter under nitrogen at a heating rate of
10°C min−1. UV–vis spectra: Kontron Instruments
UVIKON 922 spectrophotometer. 1H-NMR spectra:
AC 250 (250 MHz, Bruker) and ARX 400 (400 MHz,
Bruker). 13C-NMR spectra (including DEPT se-
quences): ARX 400 (101 MHz). Peak assignments were
possible after two-dimensional experiments (COSY).
31P-NMR spectra (1H-decoupled): ARX 400 (162
MHz), external standard 85% H3PO4. Elemental analy-
ses: Mikroanalytisches Labor, Universita¨t Regensburg.
X-ray structural analyses: STOE IPDS-diffractometer
(Mo–Ka radiation, graphite monochromator), SIR97
[22] and SHELXS-97 [23]. A summary of the crystallo-
graphic results is presented in Table 6.
Fig. 6. Top view of 6. Hydrogen atoms and menthyl groups are
omitted for clarity.
Ferrocene, BuLi, (−)-menthol and (−)-borneol
were commercial products. The compounds (−)-men-
thylchloride [24], (−)-bornylchloride [25], (−)-
dichloromenthylphosphine [26], (−)-bornyldichloro-
phosphine [25], 1,1%-dilithioferrocene (TMEDA adduct)
[27] and 1,1%-ferrocenediylphenylphosphine 1 [10] were
prepared according to literature methods. The asym-
metric hydrogenation of folic acid was performed as
described [21].
Fig. 7. DSC thermogram of (−)-Fe(h5-C5H4)2PMen (2) (10°C
3.2. Preparation of (−)-Fe(p5-C5H4)2PMen (2)
min−1).
In freshly distilled 1,2-dimethoxyethane (DME) (150
ml), fcLi2 (TMEDA) (1.57 g, 5.0 mmol) was suspended
with stirring at −45°C. To this mixture was added a
precooled solution of Cl2PMen (1.20 g, 5.0 mmol) in
DME (30 ml). The resulting mixture was allowed to
slowly warm to r.t. Stirring was continued for 2 h. The
resulting reaction mixture was filtered, the solvent was
removed, and the residue was dried. The resulting solid
was dissolved in hexanes and loaded on a basic Al2O3
column. A red band eluting with 20:1 hexanes–CH2Cl2
was collected. The solution was concentrated and
cooled to −35°C, which resulted in the formation of
deep red crystals (0.62 g, 1.8 mmol, 35%).
Scheme 5. Thermal ROP of the [1]ferrocenophanes.
3. Experimental
1
3
M.p. 131°C. H-NMR (C6D6): l=0.79 (d, J=6.8
3
3.1. General considerations
Hz, 3H), 0.81–0.92 (m, 1H), 0.87 (d, J=6.3 Hz, 3H),
3
0.92 (d, J=6.7 Hz, 3H), 0.99 (m, 1H), 1.08 (m, 1H),
All manipulations and reactions were carried out
under an inert atmosphere using standard Schlenk tech-
niques. Reagent-grade solvents were dried and distilled
prior to use. Chromatographic materials alumina and
silica gel were saturated with N2. Three acronyms are
used successively: Men for the (1R,3R,4S)-menthyl
1.40 (m, 1H), 1.58 (m, 1H), 1.61–1.66 (m, 1H), 1.65–
1.74 (m, 1H), 2.18–2.26 (m, 1H), 2.25 (m, 1H), 2.48 (m,
1H), 4.15 (m, 1H, Hfc), 4.19 (m, 1H, Hfc), 4.24–4.26 (m,
1H, Hfc), 4.28–4.29 (m, 2H, Hfc), 4.39–4.41 (m, 1H,
Hfc), 4.42 (m, 1H, Hfc), 4.44 (m, 1H, Hfc). 13C-NMR
1
(C6D6): l=16.5 (s), 20.1 (d, JCP=48.4 Hz, ipso-Cfc),

H. Brunner et al. / Journal of Organometallic Chemistry 601 (2000) 211–219
217
1
22.3 (s), 22.9 (s), 22.9 (d, JCP=51.6 Hz, ipso-Cfc), 25.6
(m, 1H, Hfc), 4.41–4.43 (m, 1H, Hfc), 4.44–4.46 (m,
1H, Hfc). 13C-NMR (C6D6): l=16.6 (s), 16.9 (d, JCP
(d, 3JCP=11.7 Hz), 29.4 (d, 3JCP=9.4 Hz), 33.8 (d,
=
2
3JCP=9.0 Hz), 35.1 (d, JCP=11.7 Hz), 35.2 (s), 37.3
50.7 Hz, ipso-Cfc), 18.8 (s), 19.4 (d, JCP=1.8 Hz), 22.1
(d, JCP=55.3 Hz, ipso-Cfc), 28.8 (s), 32.2 (d, JCP=29.6
Hz), 34.0 (d, JCP=17.7 Hz), 38.7 (d, JCP=9.1 Hz),
45.5 (d, JCP=2.5 Hz), 48.7 (d, JCP=11.3 Hz), 50.0 (d,
2
1
(d, JCP=10.8 Hz), 49.4 (d, JCP=21.5 Hz), 76.0–77.8
(m, Cfc). 31P-NMR (C6D6): l=9.3 (s). MS (EI, 70 eV),
m/z (rel. int.): 354.3 (100) [M]. [h]D (c=0.4, hexanes)=
−131°. UV–vis: umax=489 nm, m=2900 (cm2 mol−1).
Anal. Calc. for C20H27FeP (354.2): C, 67.80; H, 7.70.
Found: C, 67.27; H, 7.72%.
J
CP=3.8 Hz), 75.8–78.0 (m, 8C, Cfc). 31P-NMR
(C6D6): l=3.9 (5%), −3.0 (95%). MS (EI, 70 eV), m/z
(rel. int.): 352.3 (100) [M]. [h]D (c=0.5, hexanes)= −
53°. UV–vis: umax=498 nm, m=3100 (cm2 mol−1).
Anal. Calc. for C20H25FeP (352.2): C, 68.19; H, 7.17.
Found: C, 68.01; H, 7.22%.
3.3. Preparation of (−)-Fe(p5-C5H4)2PBor (3)
In freshly distilled hexanes (100 ml), fcLi2 (TMEDA)
(3.02 g, 9.6 mmol) was suspended with stirring and
cooled to −78°C. To this mixture was added dropwise
by cannula a solution of Cl2PBor (2.30 g, 9.6 mmol) in
hexanes (50 ml). Stirring was continued as the solution
was slowly warmed to r.t. over which period (12 h) the
color had become dark red. The resulting reaction
mixture was then filtered over Celite®, the solvent was
removed from the filtrate, and the residue was dried.
The resulting solid was dissolved in hexanes and loaded
on an Al2O3 column. A red band eluting with 20:1
hexanes–CH2Cl2 was collected. After removal of the
solvent, the residue was dried in vacuo to give 3.
Recrystallization from hexanes afforded deep red
needles (1.49 g, 4.2 mmol, 44%).
3.4. Preparation of
(p5-C5Me5)Mn(CO)2[Fe(p5-C5H4)2PPh] (4)
Cp*(CO)2Mn(THF) was prepared from Cp*-
(CO)3Mn (310 mg, 1.80 mmol) in THF (200 ml) by
irradiation with a medium-pressure Hg arc lamp. 1,1%-
Ferrocenediylphenylphosphine 1 (490 mg, 1.70 mmol)
in THF (20 ml) was added to the solution at −30°C.
The mixture was allowed to warm to r.t. and stirring
was continued for 12 h. The solvent was removed.
Recrystallization from CH2Cl2–hexanes at −35°C
gave reddish plates (595 mg, 1.11 mmol, 66%).
M.p. 160°C (dec.). 1H-NMR (CDCl3): l=1.64 (s,
15H), 4.27–4.29 (m, 2H, Hfc), 4.37–4.42 (m, 2H, Hfc),
4.47–4.52 (m, 2H, Hfc), 4.92–4.97 (m, 2H, Hfc), 7.38–
7.85 (m, 5H). 13C-NMR (CDCl3): l=9.8 (s), 29.6 (d,
1
M.p. 96°C. H-NMR (C6D6): l=0.86 (s, 3H), 0.99
(s, 3H), 1.02 (s, 3H), 1.19–1.34 (m, 2H), 1.45–1.54 (m,
1H), 1.59–1.63 (m, 1H), 1.67–1.77 (m, 1H), 2.06–2.16
(m, 1H), 2.47–2.55 (m, 1H), 2.73–2.79 (m, 1H), 4.18–
4.22 (m, 2H, Hfc), 4.24–4.29 (m, 3H, Hfc), 4.35–4.37
1JCP=13.6 Hz), 76.4 (d, JCP=4.1 Hz), 76.5 (d, JCP
=
6.3 Hz), 77.4 (d, JCP=3.5 Hz), 78.0 (d, JCP=8.1 Hz),
93.0 (s), 128.3 (d, JCP=8.8 Hz), 129.3 (d, JCP=1.9
Table 6
Crystallographic data and experimental parameters for compound 2, 4, 5 and 6
Compound
2
4
5
6
Empirical formula
Formula weight (g mol−1
Crystal system
Space group
C20H27FeP
354.24
Monoclinic
P21
C28H28FeMnO2P
538.25
Monoclinic
P21/n
C40H54Cl2Fe2P2Pd
885.79
Trigonal
P3221
C40H54Fe2P2
708.47
Monoclinic
P21
)
Z
2
4
3
2
,
a (A)
8.3397(8)
10.1177(9)
10.6392(10)
104.992(11)
867.16
1.357
0.956
376
8.4816(5)
20.5252(14)
13.7331(14)
92.643(8)
2388.2(3)
1.479
13.6152(6)
13.6152(6)
18.8645(6)
90
3028.5
1.457
10.0800(7)
12.6670(10)
14.7759(10)
109.563(7)
1777.7(2)
1.324
,
b (A)
,
c (A)
i (°)
3
,
V (A )
Dcalc (Mg m−3
)
Absorption coefficient (mm−1
F(000)
)
1.2
1112
1.39
1368
0.933
752
Theta range (°)
Reflections
2.53–28.05
14876
1.79–25.66
32678
1.73–25.77
42585
2.1–25.8
24734
Rint
0.0410
0.077
0.0761
0.057
Data/parameters
Goodness-of-fit on F2
R1/wR2 [I\2|(I)]
R1/wR2 (all data)
4117/307
0.997
0.0289/0.0615
0.0372/0.0642
0.365/−0.291
4502/350
0.999
0.0339/0.0719
0.0422/0.0748
0.434/−0.299
3858/277
0.856
0.0248/0.0413
0.0382/0.0434
0.305/−0.211
6744/525
0.913
0.0347/0.0677
0.0489/0.0705
0.492/−0.254
−3
,
Largest difference peak and hole (e A
)

218
H. Brunner et al. / Journal of Organometallic Chemistry 601 (2000) 211–219
1
Hz), 130.4 (d, JCP=10.0 Hz), 138.2 (d, JCP=37.3 Hz),
3.7. Thermal ring-opening polymerization of 1, 2 and 3
234.7 (d, JCP=23.8 Hz, CO). 31P-NMR (CDCl3): l=
2
109.7 (s). IR (KBr): 1922, 1855 (CꢁO) cm−1. MS (FD,
CHCl3), m/z: 538.1 [M]. Anal. Calc. for
C28H28FeMnO2P (538.3): C, 62.48; H, 5.25. Found: C,
62.19; H, 5.38%.
The thermal ROP of 1, 2 and 3 was carried out as
described for the synthesis of polymer 8.
A small tube was charged with 2 (192 mg, 0.54 mol)
and sealed under vacuum (0.01 mmHg). It was heated
to 195°C for 2 h. The initially molten sample became
immobile after 15 min. After cooling down, the con-
tents were washed with hexanes and dissolved in
CH2Cl2. The resulting solution was filtered and the
solvent was removed to give 8 (125 mg, 0.35 mol, 65%).
Data for polymer 7: thermal ROP conditions for 1
(from DSC) with 1 h at 120°C; 1H-NMR (CD2Cl2):
l=3.6–4.7 (br, 8H, Cp), 6.8–7.9 (br, 5H, Ph). 31P-
NMR (CD2Cl2): l= −33.3 (br).
Data for polymer 8: thermal ROP conditions (from
DSC) for 2 with 2 h at 195°C; 31P-NMR (CDCl3):
l= −29.3 (br). MS (FD, CH2Cl2): 708.3 [M]2, 1062.2
[M]3, 1416.2 [M]4, 1770.9 [M]5. Anal. Calc. for
C20H27FeP ([354.2]n): C, 67.80; H, 7.70. Found: C,
66.05; H, 7.57%.
3.5. Preparation of
(−)-trans-PdCl2[Fe(p5-C5H4)2PMen]2 (5)
A solution of 2 (150 mg, 0.42 mmol) in toluene (30
ml) was added to a slurry of Pd(cod)Cl2 (61 mg, 0.21
mmol) in 60 ml of toluene. The mixture was stirred for
12 h and the solvent was removed. Recrystallization
from CH2Cl2 gave small red crystals (125 mg, 0.14
mmol, 68%).
1
M.p. 115°C (dec.). H-NMR (CDCl3): l=0.83 (d,
3J=6.6 Hz, 6H), 0.96 (d, J=6.5 Hz, 6H), 1.03 (d,
3
3J=6.6 Hz, 6H), 1.00–1.12 (m, 2H), 1.19–1.31 (m,
2H), 1.38–1.49 (m, 2H), 1.80–1.89 (m, 2H), 1.90–2.06
(m, 4H), 2.14–2.22 (m, 2H), 2.28–2.39 (m, 2H), 2.48–
2.58 (m, 2H), 2.79–2.87 (m, 2H), 4.48–4.50 (m, 2H,
Hfc), 4.51–4.55 (m, 8H, Hfc), 4.63–4.65 (m, 2H, Hfc),
4.97–4.99 (m, 2H, Hfc), 5.09–5.11 (m, 2H, Hfc). 31P-
NMR (CDCl3): l=49.2 (s). MS (FD, CH2Cl2), m/z:
886.3 (100) [M]. [h]D (c=1.6, CHCl3)= −97°. Anal.
Calc. for C40H54Cl2Fe2P2Pd (885.8): C, 54.20; H, 6.15.
Found: C, 54.43; H, 6.22%.
Data for polymer 9: thermal ROP conditions for 3
(from DSC) with 2 h at 190°C; 31P-NMR (CDCl3):
l= −34.4 (br). MS (FD, CH2Cl2): 704.2 [M]2, 1056.9
[M]3 to 2818.0 [M]8. Anal. Calc. for C20H25FeP
([352.2]n): C, 68.19; H, 7.17. Found: C, 67.12; H,
6.99%.
4. Supplementary material
3.6. Preparation of [Fe(p5-C5H4)2PMen]2 (6)
Crystallographic data for the X-ray structure analy-
ses have been deposited with the Cambridge Crystallo-
graphic Data Centre, CCDC nos. 136996 (2), 136993
(4), 136995 (5), 136994 (6). Copies can be obtained free
of charge from The Director, CCDC, 12 Union Road,
Cambridge, CB2 1EZ, UK (fax: +44-1223-336033;
In freshly distilled hexanes (100 ml), fcLi2(TMEDA)
(0.79 g, 2.5 mmol) was suspended with stirring and
cooled to ca. −40°C. To this mixture were added
dropwise by cannula 200 ml of a solution of Cl2PMen
(0.60 g, 2.5 mmol) in hexanes. Stirring was continued as
the reaction solution slowly warmed to r.t. After 3 h,
the slightly reddish mixture was filtered over Celite®
and the solvent was removed. The resulting solid was
dissolved in CH2Cl2 and loaded on an Al2O3 column. A
yellow band eluting with 1:2 hexanes–CH2Cl2 was col-
lected. Purification of the product 6 was achieved with
MLC on Merck–Lobar® columns of type B (310×25
mm ¥). Recrystallization from 10:1 CH2Cl2–hexanes
gave small yellow crystals (36 mg, 51 mmol, 2%).
e-mail:
deposit@ccdc.ac.uk
or
www:
http//
www.ccdc.cam.ac.uk).
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