Novel [3]ferrocenophanes: Syntheses, redox properties and molecular structures of [Fe{(η5-C5H4)CMe 2}2PR] (R = Ph, Cy)

Article abstract of DOI:10.1016/j.poly.2005.04.026

6,6-Dimethylfulvene reacts with Li₂PR to give Li ₂[{(C₅H₄)CMe₂}₂PR] [R = Ph (1), Cy (2)]. The ferrocenophanes [Fe{(η⁵-C₅H ₄)CMe₂}₂PR] [R = Ph (3), Cy (4)] are obtained in good yield from the lithium reagents 1 and 2 and FeCl₂. Compounds 3 and 4 were characterised spectroscopically (¹H, ¹³C, ³¹P, IR, MS), and by crystal structure determination. Electrochemical investigation shows that 3 undergoes a one-electron oxidation in CH ₂Cl₂ solution, which is chemically reversible on the short timescale of cyclic voltammetry, but in the longer time frame of macroelectrolysis the monocation [3]⁺ forms a new species that we tentatively assign as [Fe{(η⁵-C₅H₄)CMe ₂}₂P(O)Ph].

Full text of DOI:10.1016/j.poly.2005.04.026

Polyhedron 24 (2005) 1340–1346
www.elsevier.com/locate/poly
Novel [3]ferrocenophanes: Syntheses, redox properties and
molecular structures of [Fe{(g5-C5H4)CMe2}2PR] (R = Ph, Cy)
a
Thomas Ho¨cher , Arnaldo Cinquantini , Piero Zanello , Evamarie Hey-Hawkins
b
b
a,
*
a
Institut fu¨r Anorganische Chemie, Universita¨t Leipzig, Johannisallee 29, D-04103 Leipzig, Germany
b
`
Dipartimento di Chimica dellꢀUniversita di Siena, Via Aldo Moro, 53100 Siena, Italy
Received 18 March 2005; accepted 6 April 2005
Available online 23 June 2005
Abstract
6,6-Dimethylfulvene reacts with Li2PR to give Li2[{(C5H4)CMe2}2PR] [R = Ph (1), Cy (2)]. The ferrocenophanes [Fe{(g5-
C5H4)CMe2}2PR] [R = Ph (3), Cy (4)] are obtained in good yield from the lithium reagents 1 and 2 and FeCl2. Compounds 3
and 4 were characterised spectroscopically (1H, 13C, 31P, IR, MS), and by crystal structure determination. Electrochemical investi-
gation shows that 3 undergoes a one-electron oxidation in CH2Cl2 solution, which is chemically reversible on the short timescale of
cyclic voltammetry, but in the longer time frame of macroelectrolysis the monocation [3]+ forms a new species that we tentatively
assign as [Fe{(g5-C5H4)CMe2}2P(O)Ph].
ꢀ 2005 Elsevier Ltd. All rights reserved.
Keywords: [3]Ferrocenophanes; P ligands; Electrochemistry
1. Introduction
During our work on P-functionalised cyclopentadi-
enes [14–39] we observed the formation of
Li2[{(C5H4)CMe2}2PR] [R = Ph (1), Cy (2)] as a by-
product in the preparation of Li[(C5H4)CMe2PHR]
[R = Ph, Cy], and we have now developed a high yield
synthesis of the former product. Here we report the first
[3]ferrocenophanes of these ligands, namely, [Fe{(g5-
C5H4)CMe2}2PR] [R = Ph (3), Cy (4)].
Ferrocene derivatives usually show high stability and
are generally non-toxic. Thus, their industrial applica-
tions include additives for heating oil to reduce formation
of soot, iron-containing fertilizer, UV absorbers and pro-
tective coatings for rockets and satellites [1]. While
numerous ferrocenophanes have been reported, the num-
ber of structurally characterised compounds in which the
cyclopentadienyl ligands are linked by a P-functionalised
bridge is limited to [1]ferrocenophanes [2–11], the [2]fer-
rocenophane [Fe{(C5Me4)(C5H4)}CH2PPh] [12], and
some adducts of the [5]ferrocenophane [Fe{(g5-
C5H4)CH2CH2}2PPh] and the corresponding phosphine
oxide [Fe{(g5-C5H4)CH2CH2}2P(O)Ph] [13]. To our
knowledge no crystal structures of [3]ferrocenophanes
with a C–P–C bridge have been reported to date.
2. Results and discussion
2.1. Synthesis of Li2[{(C5H4)CMe2}2PR] [R = Ph (1),
Cy (2)] and [Fe{(C5H4)CMe2}2PR] [R = Ph (3), Cy
(4)]
The reaction of Li2PR with two equivalents of 6,6-
dimethylfulvene gave Li2[{(C5H4)CMe2}2PR] [R = Ph
(1), Cy (2)] as extremely air-sensitive colourless powders
(Eq. (1)).
*
Corresponding author. Tel.: +493419736151; fax: +493419739319.
E-mail address: hey@rz.uni-leipzig.de (E. Hey-Hawkins).
0277-5387/$ - see front matter ꢀ 2005 Elsevier Ltd. All rights reserved.
doi:10.1016/j.poly.2005.04.026

T. Ho¨cher et al. / Polyhedron 24 (2005) 1340–1346
1341
the 13C NMR spectrum, a large P–C coupling constant
is observed for the ipso carbon atom and two signals for
the ortho carbon atoms of the phenyl ring. The latter
suggest hindered rotation about the P–C(Ph) bond.
In the 1H NMR spectra of 3 and 4, two doublets with
Li2PR
2
+
R
P
3
3
(2 Li+)
different JP–H coupling constants [1.09 ppm, JP–H
3
=
16.8 Hz and 1.65 ppm, JP–H = 2.8 Hz (3); 1.39 ppm,
3
3JP–H = 15.0 Hz and 1.55 ppm, JP–H = 2.4 Hz (4)] are
observed for the two inequivalent methyl groups, one
of which has a trans and the other a cis orientation to
the lone pair of electrons of the phosphorus atom.
1 (R = Ph)
2 (R = Cy)
ð1Þ
The compounds Li[(C5H4)CMe2PHR] (R = Ph, Cy)
2.3. Molecular structures of [Fe{(C5H4)CMe2}2PR]
[R = Ph (3), Cy (4)]
are always obtained as by-products in ca. 40% yield.
We assume that Li2PR attacks the methyl groups of
6,6-dimethylfulvene to give LiPHR, which then reacts
with dimethylfulvene to give the observed by-products.
The amount of Li[(C5H4)CMe2PHR] was determined
by 31P NMR spectroscopy and a corresponding amount
of BuLi was added followed by 6,6-dimethylfulvene to
give 1 in high yield and purity (97%) and 2 as a mixture
with the monolithio salt (ca. 70% purity).
Attempts to further purify 2 failed. Therefore, prepa-
ration of the [3]ferrocenophane was carried out with the
mixture of 2 and Li[(C5H4)CMe2PHR], and [3]ferroce-
nophane 4 was purified by recrystallisation from tolu-
ene, while 3 was obtained from pure 1 and FeCl2 in
THF (Eq. (2)). The [3]ferrocenophanes are obtained as
orange-yellow powders.
Yellow needles of 3 and 4 were obtained after recrys-
tallisation from n-hexane. Compound 3 (Fig. 1) crystal-
lises in the monoclinic space group P21/n with four
molecules in the unit cell, and compound 4 (Fig. 2) in
the monoclinic space group C2/c with eight molecules
in the unit cell. Selected bond lengths and angles are gi-
ven in Table 1. In both [3]ferrocenophanes, the cyclo-
pentadienyl rings are almost synperiplanar and are
nearly parallel [deviation 3.9ꢁ (3) and 4.6ꢁ (4)]. The small
deviation from being parallel is presumably caused by
the phosphanylalkyl bridge. The two methyl groups
are inequivalent; one has a trans and the other a cis ori-
entation to the lone pair of electrons of the phosphorus
atom. In 3 the phenyl ring and the cyclopentadienyl
rings are almost parallel (deviations: 9.6ꢁ and 8.0ꢁ).
n
R
(2 Li+)
+
FeCl2
P
1 (R = Ph)
2 (R = Cy)
C16
ð2Þ
C8
C7
- 2 LiCl
Fe
P
R
Error
C9
C15
C6
Fe1
C2
C10
C14
C17
3 (R = Ph)
4 (R = Cy)
C18
C19
P1
2.2. Spectroscopic properties of
Li2[{(C5H4)CMe2}2PR] [R = Ph (1), Cy (2)] and of
[Fe{(C5H4)CMe2}2PR] [R = Ph (3), Cy (4)]
C3
C22
C11
C21
Error
C20
C4
Compound 1 was characterised by H, 13C, 31P and
1
C1
C5
7Li NMR spectroscopy, and 2 only by 31P NMR spec-
C12
1
troscopy. In the H NMR spectrum, the methyl groups
of the CMe2 group in 1 are inequivalent and exhibit dif-
ferent chemical shifts and coupling constants (0.95 ppm,
C13
3
3JP–H = 15.5 Hz and 1.79 ppm, JP–H = 2.6 Hz). Two
Fig. 1. Molecular structure of [Fe({(g5-C5H4)CMe2}2PPh)] (3) show-
ing the atom-numbering scheme employed (ORTEP plot, 50%
probability, SHELXTL PLUS; XP). Hydrogen atoms are omitted for clarity.
multipletts are observed at 5.21 and 5.52 ppm for the ex-
pected AA0BB0 coupling pattern of the C5H4 rings. In

1342
T. Ho¨cher et al. / Polyhedron 24 (2005) 1340–1346
Table 1
Selected distances (A) and bond angles (ꢁ) for 3 and 4
C12
˚
3
C13
C17
Fe(1)–C(2)
Fe(1)–C(10)
Fe(1)–C(7)
Fe(1)–C(6)
Fe(1)–C(4)
Fe(1)–C(5)
Fe(1)–C(9)
Fe(1)–C(8)
Fe(1)–C(1)
Fe(1)–C(3)
P(1)–C(17)
P(1)–C(11)
P(1)–C(14)
C(1)–C(5)
C(1)–C(2)
C(1)–C(11)
C(2)–C(3)
C(4)–C(5)
C(14)–C(15)
C(14)–C(16)
C(6)–C(10)
C(6)–C(7)
C(6)–C(14)
C(7)–C(8)
C(8)–C(9)
C(9)–C(10)
C(11)–C(12)
C(11)–C(13)
C(17)–C(22)
C(17)–C(18)
C(18)–C(19)
C(19)–C(20)
C(20)–C(21)
C(21)–C(22)
2.034(2)
2.035(2)
2.035(2)
2.034(2)
2.037(2)
2.039(2)
2.040(2)
2.042(3)
2.045(2)
2.045(2)
1.844(2)
1.899(2)
1.900(2)
1.430(3)
1.435(3)
1.516(3)
1.421(3)
1.431(4)
1.534(3)
1.544(3)
1.428(3)
1.437(3)
1.516(3)
1.422(3)
1.402(4)
1.425(4)
1.524(3)
1.549(3)
1.389(3)
1.402(3)
1.382(3)
1.369(4)
1.380(4)
1.387(4)
C2
C11
C3
C1
Error
C5
C4
C19
C18
P1
Fe1
C21
C22
C20
C14
C7
C6
C8
Error
C15
C16
C10
C9
Fig. 2. Molecular structure of [Fe({(g5-C5H4)CMe2}2PCy)] (4) show-
ing the atom-numbering scheme employed (ORTEP plot, 50%
probability, SHELXTL PLUS; XP). Hydrogen atoms are omitted for clarity.
2.4. Electrochemistry
Fig. 3 shows the cyclic voltammetric behaviour of
[Fe{(g5-C5H4)CMe2}2PPh] (3) in CH2Cl2 solution.
As expected for a monoferrocene complex, it under-
goes an oxidation process (Eo = +0.37 V, versus SCE)
0
with features of chemical reversibility. In fact, analysis
of the cyclic voltammetric responses with scan rate
increasing from 0.02 to 2.0 V sꢀ1 shows that: (i) the cur-
rent function ipa Æ vꢀ1/2 decreases by about 10% for each
10-fold increase of the scan rate; (ii) the current ratio ipc/
ipa remains constantly equal to 1; and (iii) the peak-to-
peak separation progressively increases from 76 to 182
mV. These parameters are diagnostic for an electro-
chemically quasireversible one-electron process which
is chemically reversible on the short timescale of cyclic
voltammetry [40]. In reality, as deducible from Fig.
3(b)–(d), in the longer timeframe of controlled potential
coulometry (Ew = +0.7 V) the process is accompanied by
the formation of a new species which in turn undergoes
C(1)–C(11)–C(13)
C(12)–C(11)–C(13)
C(6)–C(14)–C(15)
C(6)–C(14)–C(16)
C(10)–C(6)–C(7)
C(8)–C(7)–C(6)
108.2(2)
107.2(2)
110.3(2)
108.6(2)
106.5(2)
108.8(2)
107.7(2)
121.3(2)
106.6(2)
107.9(2)
108.8(2)
107.9(2)
107.7(2)
126.3(2)
127.2(2)
117.2(2)
119.3(3)
108.2(3)
C(9)–C(8)–C(7)
C(19)–C(18)–C(17)
C(5)–C(1)–C(2)
C(4)–C(3)–C(2)
C(3)–C(4)–C(5)
C(1)–C(5)–C(4)
oxidation at higher potential (Eo = +0.80 V). On step-
0
wise oxidation, the original yellow solution (kmax = 440
nm) tends to become blue after consumption of 0.7 elec-
trons per molecule (kmax = 690 nm) (Fig. 4); then, after
consumption of about 1 electron per molecule, the solu-
tion remains blue but the band shows overlap of two
close absorptions (kmax = 660 and 690 nm); finally, after
consumption of 1.1 electrons per molecule the solution
again takes on a yellow colour but absorbs at different
wavelengths from the original solution (kmax = 360
nm). On further exhaustive oxidation in correspondence
of the second anodic process (Ew = +1.0 V), about two
electrons per molecule are consumed. The final solution
turns blue again and the spectrum only shows an
absorption at kmax = 690 nm.
C(15)–C(14)–C(16)
C(10)–C(6)–C(14)
C(7)–C(6)–C(14)
C(22)–C(17)–C(18)
C(19)–C(20)–C(21)
C(6)–C(10)–C(9)
C(2)–C(1)–C(11)
C(1)–C(11)–C(12)
C(8)–C(9)–C(10)
C(11)–P(1)–C(14)
C(12)–C(11)–P(1)
C(13)–C(11)–P(1)
C(15)–C(14)–P(1)
C(22)–C(17)–P(1)
C(17)–P(1)–C(11)
126.9(2)
110.9(2)
108.9(2)
109.16(9)
119.2(2)
104.5(2)
118.5(2)
115.2(2)
106.26(9)

T. Ho¨cher et al. / Polyhedron 24 (2005) 1340–1346
1343
Table 1 (continued)
Table 1 (continued)
3
4
C(21)–C(22)–C(17)
C(3)–C(2)–C(1)
C(20)–C(19)–C(18)
C(5)–C(1)–C(11)
C(1)–C(11)–P(1)
C(6)–C(14)–P(1)
C(16)–C(14)–P(1)
C(18)–C(17)–P(1)
C(17)–P(1)–C(14)
121.1(2)
108.8(2)
120.6(2)
126.4(2)
106.3(1)
106.5(1)
104.8(2)
127.5(2)
103.44(9)
C(2)–C(1)–C(5)
C(8)–C(9)–C(10)
C(2)–C(1)–C(11)
C(5)–C(1)–C(11)
C(8)–C(7)–C(6)
C(9)–C(8)–C(7)
C(9)–C(10)–C(6)
C(3)–C(2)–C(1)
C(3)–C(4)–C(5)
C(4)–C(5)–C(1)
C(20)–C(21)–C(22)
C(20)–C(19)–C(18)
C(14)–P(1)–C(11)
C(17)–P(1)–C(14)
C(18)–C(17)–P(1)
C(22)–C(17)–P(1)
106.0(2)
108.4(2)
126.1(2)
127.9(2)
108.6(2)
108.3(2)
108.2(2)
108.8(2)
108.6(2)
108.5(2)
111.9(2)
111.3(2)
108.89(8)
108.50(8)
121.3(1)
109.6(1)
4
Fe(1)–C(4)
Fe(1)–C(2)
Fe(1)–C(7)
Fe(1)–C(10)
Fe(1)–C(3)
Fe(1)–C(5)
Fe(1)–C(8)
Fe(1)–C(9)
Fe(1)–C(1)
P(1)–C(17)
P(1)–C(14)
P(1)–C(11)
C(14)–C(6)
C(14)–C(15)
C(14)–C(16)
C(17)–C(18)
C(6)–C(10)
C(3)–C(4)
C(1)–C(2)
C(1)–C(5)
C(7)–C(8)
C(9)–C(8)
C(9)–C(10)
C(2)–C(3)
C(18)–C(19)
C(11)–C(12)
C(20)–C(21)
C(22)–C(21)
C(17)–C(22)
C(5)–C(4)
C(11)–C(1)
C(11)–C(13)
2.031(2)
2.031(2)
2.033(2)
2.035(2)
2.038(2)
2.040(2)
2.046(2)
2.046(2)
2.051(2)
1.887(2)
1.905(2)
1.907(2)
1.518(3)
1.527(3)
1.548(3)
1.535(3)
1.441(3)
1.393(4)
1.433(3)
1.434(3)
1.426(3)
1.404(4)
1.428(3)
1.422(3)
1.527(3)
1.547(3)
1.514(4)
1.528(3)
1.534(3)
1.422(3)
1.515(3)
1.530(3)
Fig. 3. Cyclic voltammetric responses recorded at a platinum electrode
for a CH2Cl2 solution of [Fe{(g5-C5H4)CMe2}2PPh] (3) (1.9 · 10ꢀ3
mol dmꢀ3
) before and after controlled potential coulometry.
[NBu4][PF6] (0.2 mol dmꢀ3) supporting electrolyte. (a) Original solu-
tion; (b) after consumption of 0.7 electrons per molecule; (c) after
consumption of 0.9/1.0 electrons per molecule; (d) after consumption
of 1.1 electrons per molecule. (d) Starting potential. Scan rate: 0.2
C(1)–C(11)–C(13)
C(1)–C(11)–C(12)
C(13)–C(11)–C(12)
C(1)–C(11)–P(1)
C(13)–C(11)–P(1)
C(12)–C(11)–P(1)
C(7)–C(6)–C(10)
C(7)–C(6)–C(14)
C(10)–C(6)–C(14)
C(21)–C(22)–C(17)
C(6)–C(14)–C(15)
C(6)–C(14)–C(16)
C(15)–C(14)–C(16)
C(19)–C(18)–C(17)
C(18)–C(17)–C(22)
C(17)–P(1)–C(11)
C(6)–C(14)–P(1)
C(15)–C(14)–P(1)
C(16)–C(14)–P(1)
C(19)–C(20)–C(21)
C(4)–C(3)–C(2)
111.3(2)
107.2(2)
107.5(2)
108.5(1)
116.9(1)
104.9(1)
106.5(2)
126.8(2)
126.7(2)
112.2(2)
109.5(2)
107.4(2)
108.8(2)
111.6(2)
109.6(2)
102.95(8)
106.1(1)
119.0(1)
105.4(1)
110.8(2)
108.1(2)
V sꢀ1
.
In an attempt to account for such electrochemical
behaviour, it is useful to note that the formation of
uncharacterised products was also observed in the irre-
versible oxidation of both the [1]ferrocenophane
[Fe(g5-C5H4)2PPhMe]+ [41] and the [5]ferrocenophane
[Fe{(g5-C5H4)CH2CH2}2PPh] [13]. In particular, in the
latter case, this has been attributed to a dimerisation
reaction (with formation of a P–P bond) rather than
to formation of the corresponding phosphine oxide
[Fe{(g5-C5H4)CH2CH2}2P(O)Ph] [13], since the oxida-
tion potential of the by-product arising from the pri-
mary process [Fe{(g5-C5H4)CH2CH2}2PPh]0/+ looks
different from that of a crystallographically character-
ised sample of [Fe{(g5-C5H4)CH2CH2}2P(O)Ph]. We

1344
T. Ho¨cher et al. / Polyhedron 24 (2005) 1340–1346
Table 3
Formal electrode potentials (V, vs. SCE) for the one-electron oxidation
of different phosphaferrocenophanes
Eo
Solvent
Ref.
0
Complex
[Fe(C5Me4)2PPh]
+0.37
+0.50
+1.11a
+0.26
+0.37
+0.04a
+0.39
CH2Cl2
THF
[45]
[45]
[41]
[Fe(C5H4)2PPhMe]+
[Fe{(C5Me4)(C5H4)}CH2PPh]
[Fe{(C5H4)CMe2}2PPh]
[Fe{(C5H4)CH2CH2}2PPh]
[Fe(C5H5)2]
CH2Cl2
CH2Cl2
CH2Cl2
MeCN
CH2Cl2
[12]
b
[13]
b
a
Peak potential for irreversible processes.
This work.
b
On this basis, a tentative explanation of the electro-
chemical data would be that the primarily generated
ferrocenium ion [3]+ reacts with traces of air (or water
from the nominally anhydrous solvent) to give
[Fe{(g5-C5H4)CMe2}2P(O)Ph]+, which, because of the
inappropriate potential, is reduced to the corresponding
ferrocene [Fe{(g5-C5H4)CMe2}2P(O)Ph]; on application
of the proper potential, the latter is again oxidised to the
corresponding monocation.
Fig. 4. UV/Vis spectral profiles obtained on stepwise oxidation of
[Fe{(g5-C5H4)CMe2}2PPh] (3) (1.9 · 10ꢀ3 mol dmꢀ3) in correspon-
dence of the primary anodic process. CH2Cl2 solution containing
[NBu4][PF6] (0.2 mol dmꢀ3) as supporting electrolyte. (a) Original
solution; (b) after 0.7 electrons/molecule; (c) after 0.9/1.0 electrons/
molecule; (d) after 1.1 electrons/molecule.
note, however, that the comparison of the two oxidation
processes was done in different solvents. In our case we
are inclined to assign the secondary step as due to
Table 3 compiles the redox potentials for the
ferrocene/ferrocenium process in
phosphaferrocenophanes.
the process [Fe{(g5-C5H4)CMe2}2P(O)Ph]0/+
,
since
a
series of
[Fe{(g5-C5H4)CMe2}2PPh], even in the solid state,
proved to be air-sensitive. This assumption is also sup-
ported by the observation that a powdered sample that
was not maintained under strictly anaerobic conditions
(for about one month) also showed this second oxida-
tion step.
We note that the oxidation of methylated derivatives
such as [Fe{(C5H4)CMe2}2PPh], [Fe(C5Me4)2PPh] and
[Fe{(C5Me4)(C5H4)}CH2PPh] occurs at potentials simi-
lar to that of unsubstituted ferrocene, and this suggests
that the electron-donating ability of the bridging carbon
atoms or the cyclopentadienyl methyl groups is attenu-
ated by the electron-withdrawing ability of the PPh
group.
Table 2
Crystal data and structure refinement for 3 and 4
3
4
Empirical formula
Mr
C
376.24
22H25FeP
C22H31FeP
382.29
210(2)
3. Experimental
Temperature (K)
Crystal system
Space group
220(2)
monoclinic
P21/n
3.1. General
monoclinic
C2/c
Unit cell dimensions
˚
All experiments were carried out under purified dry
nitrogen. Solvents were dried and freshly distilled under
argon. The NMR spectra were recorded with an
a (A)
˚
15.7183(6)
8.5450(3)
15.7434(6)
117.916(1)
1868.5(1)
4
35.053(5)
6.386(5)
18.088(5)
111.124(5)
3777(3)
8
b (A)
˚
c (A)
1
AVANCE DRX 400 spectrometer (Bruker), H NMR:
b (ꢁ)
internal standard TMS; 13C NMR: internal standard
TMS; 31P NMR: external standard 85% H3PO4. The
IR spectra were recorded on an FT-IR spectrometer
Perkin–Elmer System 2000 in the range 350–4000
cmꢀ1. MS: MAT 8230 (Finnigan) 70 eV. The melting
points were determined in sealed capillaries under nitro-
gen and are uncorrected (BOETIUS). Materials and
apparatus for electrochemistry and spectroelectrochem-
istry have been described elsewhere [42]. Potential values
are referred to the saturated calomel electrode (SCE).
Li2PR (R = Ph, Cy) were prepared from PH2R and
two equivalents of MeLi. FeCl2 is commercially
available.
3
˚
V (A )
Z
qcalc. (Mg mꢀ3
F(000)
)
1.337
792
1.345
1632
Crystal size (mm)
Absorption coefficient (mmꢀ1
H range (ꢁ)
Reflections collected
Independent reflections
Rint
0.50 · 0.30 · 0.20 0.40 · 0.20 · 0.10
0.892
)
0.884
1.51–28.28
11382
4446
1.25–28.95
14839
4628
0.0255
317
0.0332
341
Parameters
R[I > 2r(I)]
0.0362
0.1124
0.475
0.0314
0.0978
0.299
wR2 (all datꢀa3)
˚
D/qmin. (e Aꢀ3
)
˚
D/qmax. (e A
)
ꢀ0.743
ꢀ0.356

T. Ho¨cher et al. / Polyhedron 24 (2005) 1340–1346
1345
3.2. Synthesis of dilithiumphenylphosphinobis(dimethyl-
methylcyclopentadienide), Li2[{(C5H4)CMe2}2PPh]
(1)
3.4. Synthesis of [bis(cyclopentadienyldimethylmethyl)-
phenylphosphino]ferrocenophane,
[Fe{(C5H4)CMe2}2PPh] (3)
6,6-Dimethylfulvene (4.33 ml, 36 mmol) was added
dropwise to a suspension of Li2PPh (2.2 g, 18 mmol)
in 50 ml of Et2O and stirred for at least 12 h, during
which time the yellow suspension turned colourless.
The solid was isolated by filtration, washed 3 times with
30 ml of Et2O and dried in vacuo. The amount of
Li[(C5H4)CMe2PHPh] was determined by 31P NMR
spectroscopy. The mixture was dissolved in 30 ml of
THF and the appropriate amount of nBuLi (correspond-
ing to the amount of Li[(C5H4)CMe2PHPh]) was added.
The solvent was evaporated, the residue was suspended
in Et2O and the appropriate amount of 6,6-dimethylful-
vene was added. After stirring for 12 h the colourless so-
lid was isolated by filtration, washed with Et2O and
n-hexane and dried. Yield: 4.9 g (81.5%) of 1 as a colour-
less air-sensitive powder. M.p.: 256 ꢁC (decomp.).
Solid 1 (1.2 g, 3.6 mmol) was added in small portions
to a suspension of FeCl2 (0.46 g, 3.6 mmol) in 50 ml of
THF. The solution turned yellow to brown. After stir-
ring overnight the solvent was evaporated and 50 ml
of Et2O was added to the remaining brown oil, giving
a brown solid and an orange solution. The solution
was filtered over dry Al2O3, and the residue washed
repeatedly with Et2O until the washings were colourless.
The Et2O fractions were combined and the solvent evap-
orated. Fifty millilitres of hexane was added to the res-
idue, filtered and the hexane evaporated leaving 1.0 g
(74%) of 3 as an orange powder. Yellow crystals were
obtained from a concentrated solution of 3 in n-hexane
at ꢀ20 ꢁC. M.p.: 143 ꢁC.
3
1H NMR (CDCl3): d 1.09 (d, JP–H = 16.8, 6H, CH3
3
in CMe2), 1.65 (d, JP–H = 2.8, 6H, CH3 in CMe2),
1H NMR (THF-d8): d 0.95 (d, 3JP–H = 15.5, 6H, CH3
4.05 (s, 2H, CH in C5H4), 4.16 (s, 2H, CH in C5H4),
4.19 (s, 2H, CH in C5H4), 4.41 (s, 2H, CH in C5H4),
7.42 (m, 3H, o- and p-CH in Ph), 7.86 (m, 2H, m-CH
3
in CMe2), 1.79 (d, JP–H = 2.6, 6H, CH3 in CMe2), 5.21
(m, 4H, CH in C5H4), 5.52 (m, 4H, CH in C5H4), 7.26
(m, 3H, o- and p-CH in Ph), 7.93 (m, 2H, m-CH in
2
in Ph). 13C{1H} NMR (CDCl3): d 24.3 (d, JP–C = 5.0,
2
2
C–CH3), 31.7 (d, JP–C = 33.9, C–CH3), 32.1 (d, JP–C
1
Ph). 13C{1H} NMR (THF-d8): d 26.20 (d, JP–C = 4.1,
C–CH3), 35.50 (d, 2JP–C = 26.5, C–CH3), 37.40 (d, 1JP–C
= 39.4, C–CH3), 102.30 (s, m-C in C5H4), 104.10 (d,
4
= 22.3, C–CH3), 67.0 (d, JP–C = 2.1, CH in C5H4),
4
67.2 (d, JP–C = 2.5, CH in C5H4), 68.8 (d, JP–C = 6.2,
3
2
2
CH in C5H4), 95.0 (d, JP–C = 12.4, ipso-C in C5H4),
3JP–C = 6.6, o-C in C5H4), 127.58 (d, JP–C = 14.1, ipso-
3
C in C5H4), 127.64 (d, JP–C = 8.4, m-C in Ph), 128.50
3
127.8 (d, JP–C = 8.3, m-C in Ph), 129.0 (s, p-C in Ph),
2
(s, p-C in Ph), 136.00 (d, JP–C = 14.1, o-C in Ph), 138
2
1
136.7 (d, JP–C = 23.9, o-C in Ph), 137.8 (d, JP–C
= 34.7, ipso-C in Ph). 31P NMR (CDCl3): d = 50.5, s.
2
1
(d, br, JP–C = 14.0, o-C in Ph), 143.80 (d, JP–C
= 41.9, ipso-C in Ph). 31P NMR (THF-d8): d 42.9, s.
IR (KBr), m (cmꢀ1): 3077 m (m(CH) aryl), 2969 s
~
7
Li NMR (THF-d8): d = ꢀ7.2, s. IR m (cmꢀ1): 3074 w
(m(CH3)), 1431 br, m (d(CH3)), 1359 m (m(CC) in
C5H4). EI-MS: m/z = 376 (100%, M+), 268 (69%,
M+ ꢀ PPh), and fragmentation products thereof. Anal.
Calc. for C22H25PFe (376): C, 70.2; H, 6.7; P, 8.2.
Found: C, 70.1; H, 5.1; P, 7.6%.
~
(m(CH) aryl), 2864 m (m(CH3)), 1462–1360 m (d(CH3)).
3.3. Synthesis of dilithiumcyclohexylphosphinobis-
(dimethylmethylcyclopentadienide),
Li2[{(C5H4)CMe2}2PCy] (2)
3.5. Synthesis of [bis(cyclopentadienyldimethylmethyl)-
cyclohexylphosphino]ferrocenophane,
[Fe{(C5H4)CMe2}2PCy] (4)
Analogously to the synthesis of 1 from Li2PCy (1 g,
7.8 mmol) in 50 ml Et2O and 6,6-dimethylfulvene (1.9
ml, 15.6 mmol). The amount of Li[(C5H4)CMe2PHCy]
was determined by 31P NMR spectroscopy. The mixture
was dissolved in 30 ml of THF and the appropriate
amount of nBuLi (corresponding to the amount of
Li[(C5H4)CMe2PHCy]) was added. The solvent was
evaporated, the residue suspended in Et2O and the
appropriate amount of 6,6-dimethylfulvene added. After
stirring for 12 h the colourless solid was isolated by fil-
tration, washed with Et2O and n-hexane and dried.
Yield: 2.5 g of 2 (m.p.: 257 ꢁC (decomp.)) as a colourless
air-sensitive powder, which contained ca. 30% of
Li[(C5H4)CMe2PHCy]. Attempts to further purify 2
failed. Therefore the mixture was employed in the syn-
thesis of 4.
The mixture containing 2 (0.50 g, 1.47 mmol) and
Li[(C5H4)CMe2PHCy] (0.15 g, 0.65 mmol), obtained as
described above, was added as a solid in small portions
to a suspension of FeCl2 (0.23 g, 1.8 mmol) in 25 ml of
THF. The solution turned yellow, then brown and final-
ly almost black. After stirring overnight the solvent was
evaporated and 50 ml of Et2O was added to the remain-
ing black oil giving a brown solid and an orange solu-
tion. The solution was filtered over dry Al2O3, and the
residue washed repeatedly with Et2O until the washings
were colourless. The Et2O fractions were combined and
the solvent evaporated. The residue was recrystallised
from 10 ml of n-hexane giving 0.27 g (48%) of 4 as yel-
low crystals. M.p.: 188 ꢁC.
31P NMR (THF-d8): d 54.0, s.

1346
T. Ho¨cher et al. / Polyhedron 24 (2005) 1340–1346
1H NMR (CDCl3): d 1.2–1.9 (br, m, 11H, CH and
CH2 in Cy), 1.39 (d, JP–H = 15.0, 6H, CH3 in CMe2),
[6] T. Mizuta, T. Yamasaki, K. Miyoshi, Chem. Lett. (2000) 924.
[7] C.E.B. Evans, A.J. Lough, H. Grondey, I. Manners, New J.
Chem. Nouv. J. Chim. 24 (2000) 447.
3
3
1.55 (d, JP–H = 2.4, 6H, CH3 in CMe2), 3.99 (s, 2H,
[8] T. Mizuta, M. Onishi, K. Miyoshi, Organometallics 19 (2000) 5005.
[9] H. Brunner, J. Klankermayer, M. Zabel, J. Organomet. Chem.
601 (2000) 211.
CH in C5H4), 4.04 (s, 2H, CH in C5H4), 4.09 (s,
2H, CH in C5H4), 4.27 (s, 2H, CH in C5H4).
2
13C{1H} NMR (CDCl3): d 24.92 (d, JP–C = 4.2, C–
CH3), 26.49 (s, C4 in Cy), 28.85 (d, JP–C = 9.3, C3
[10] C.H. Honeyman, D.A. Foucher, F.Y. Dahmen, R. Rulkens, A.J.
Lough, I. Manners, Organometallics 14 (1995) 5503.
[11] T. Mizuta, T. Yamasaki, H. Nakazawa, K. Miyoshi, Organomet-
allics 15 (1996) 1093.
3
2
in Cy), 32.43 (d, JP–C = 31.9, C–CH3), 32.65 (d, C–
2
CH3, JP–C = 26.5), 34.40 (d, JP–C = 15.2, C2 in Cy),
[12] R. Resendes, J.M. Nelson, A. Fischer, F. Ja¨kle, A. Bartole, A.J.
Lough, I. Manners, J. Am. Chem. Soc. 123 (2001) 2116.
[13] J.J. Adams, O.J. Curnow, G. Huttner, S.J. Smail, M.M. Turnbull,
J. Organomet. Chem. 577 (1999) 44.
1
38.84 (d, JP–C = 35.0, C1 in Cy), 66.37 (d, JP–C
4
4
= 2.7, CH in C5H4), 66.86 (d, JP–C = 2.0, CH in
3
C5H4), 68.66 (d, JP–C = 8.4, CH in C5H4), 68.75 (s,
[14] C. Charrier, F. Mathey, Tetrahedron Lett. 19 (1978) 2407.
[15] Review: P. Jutzi, T. Redeker, Eur. J. Inorg. Chem. (1998) 663.
[16] H. Butenscho¨n, Chem. Rev. 100 (2000) 1527.
[17] A.M. Bensley Jr., E.A. Mintz, J. Organomet. Chem. 353 (1988) 93
(and references therein).
2
CH in C5H4), 96.2 (d, JP–C = 11.3, ipso-C in C5H4).
31
P NMR (CDCl3): d 67.8, s. IR (KBr), m (cmꢀ1):
~
2970 s (m(CH3)), 1444 br, m (d(CH3)), 1359 m
(m(CC) in C5H4). EI-MS: m/z = 382 (26%, M+), 267
(100%, M+ ꢀ PCy), and fragmentation products there-
of. Anal. Calc. for C22H31PFe (382): C, 69.1; H, 8.2.
Found: C, 68.5; H, 7.3%.
[18] R.T. Kettenbach, W. Bonrath, H. Butenscho¨n, Chem. Ber. 126
(1993) 1657.
[19] B.E. Bosch, G. Erker, R. Fro¨hlich, O. Meyer, Organometallics 16
(1997) 5449.
[20] C. Charrier, F. Mathey, J. Organomet. Chem. 170 (1979) C41.
[21] T. Kauffmann, J. Ennen, H. Lhotak, A. Rensing, F. Steinseifer,
A. Woltermann, Angew. Chem. 92 (1980) 321.
3.6. Data collection and structural refinement of 3 and 4
[22] T.-F. Wang, J.-P. Juang, Y.-S. Wen, J. Organomet. Chem. 503
(1995) 117.
˚
Data (k(Mo Ka) = 0.71073 A) were collected with a
Siemens CCD (SMART) diffractometer. All observed reflec-
tions were used for refinement (SAINT) of the unit cell
parameters. Empirical absorption correction was applied
with SADABS [43]. The structures were solved by direct
methods (SHELXTL PLUS) [44]. Fe, P and C atoms were re-
fined anisotropically; H atoms were located by difference
maps and refined isotropically. Table 2 lists crystallo-
graphic details.
[23] J. Szymoniak, J. Besanc¸on, A. Dormond, C. Mo¨ıse, J. Org.
Chem. 55 (1990) 1429.
[24] N.E. Schore, J. Am. Chem. Soc. 101 (1979) 7410.
[25] N.E. Schore, L.S. Benner, B.E. LaBelle, Inorg. Chem. 20 (1981) 3200.
[26] N.E. Schore, S. Sundar, J. Organomet. Chem. 184 (1980) C44.
[27] S.R. Iyer, D.R. Tueting, N.E. Schore, J. Organomet. Chem. 320
(1987) 339.
[28] N.E. Schore, B.E. LaBelle, J. Org. Chem. 46 (1981) 2306.
[29] T.A. Mobley, R.G. Bergman, J. Am. Chem. Soc. 120 (1998) 3253.
[30] D.M. Bensley Jr., E.A. Mintz, S.J. Sussangkarn, J. Org. Chem. 53
(1988) 4417.
[31] Y. Kataoka, Y. Saito, K. Nagata, K. Kitamura, A. Shibahara,
K. Tani, Chem. Lett. (1995) 833.
4. Supplementary material
[32] M.D. Fryzuk, S.S.H. Mao, M.J. Zaworotko, L.R. MacGillivray,
J. Am. Chem. Soc. 115 (1993) 5336.
CCDC 266919 (3) and 266918 (4) contain the supple-
mentary crystallographic data for this paper. These data
can be obtained free of charge from the Cambridge
Crystallographic Data Centre (CCDC), 12 Union Road,
Cambridge CB2 1EZ, UK via www.ccdc.cam.ac.uk/
data_request/cif, e-mail: deposit@ccdc.cam.ac.uk.
[33] T. Kauffmann, J. Olbrich, Tetrahedron Lett. 25 (1984) 1967.
[34] B. Antelmann, U. Winterhalter, G. Huttner, B.C. Janssen, J.
Vogelgesang, J. Organomet. Chem. 545–546 (1997) 407.
[35] O.J. Curnow, G. Huttner, S.J. Smail, M.M. Turnbull, J. Orga-
nomet. Chem. 524 (1996) 267.
[36] Review: T. Cuenca, P. Royo, Coord. Chem. Rev. 193–195(1999)447.
[37] Review: C.S. Slone, D.A. Weinberger, C.A. Mirkin, Prog. Inorg.
Chem. 48 (1999) 233.
Acknowledgement
[38] T. Koch, E. Hey-Hawkins, Polyhedron 18 (1999) 2113.
[39] T. Koch, S. Blaurock, F.B. Somoza Jr., A. Voigt, R. Kirmse, E.
Hey-Hawkins, Organometallics 19 (2000) 2556.
P.Z. gratefully acknowledges the financial support
from the University of Siena (PAR 2003).
[40] P. Zanello, Inorganic Electrochemistry. Theory, Practice and
Application, RS.C, Cambridge, United Kingdom, 2003.
[41] T.J. Peckham, A.J. Lough, I. Manners, Organometallics 18 (1999)
1030.
References
[42] F. Fabrizi de Biani, M. Corsini, P. Zanello, H. Yao, M.E. Bluhm,
R.N. Grimes, J. Am. Chem. Soc. 126 (2004) 11360.
[43] G.M. Sheldrick, SADABS – A Program for Empirical Absorption
Correction, Go¨ttingen, 1998.
[1] A. Togni, T. Hayashi, Ferrocenes, VCH, Weinheim, 1995.
[2] M. Herberhold, F. Hertel, W. Milius, B. Wrackmeyer, J.
Organomet. Chem. 582 (1999) 352.
[44] SHELXTL PLUS, Siemens Analyt. X-ray Inst. Inc., XS: Program for
Crystal Structure Solution, XL: Program for Crystal Structure
Determination, XP: Interactive Molecular Graphics, 1990.
[45] M. Viotte, B. Gautheron, M.M. Kubicki, Y. Mugnier, R.V.
Parish, Inorg. Chem. 34 (1995) 3465.
[3] I.R. Butler, W.R. Cullen, F.W.B. Einstein, S.J. Rettig, A.J.
Willis, Organometallics 2 (1983) 128.
[4] H. Stoeckli-Evans, A.G. Osborne, R.H. Whiteley, J. Organomet.
Chem. 194 (1980) 91.
[5] I.R. Butler, W.R. Cullen, S.J. Rettig, Organometallics 6 (1987) 872.