Diferrocenylcyclopropenyl cations. Synthesis, structures, and some chemical properties

Article abstract of DOI:10.1016/j.jorganchem.2005.04.014

Synthesis of diferrocenylcyclopropenyl tetrafluoroborates with hetero-substituents in the three-membered ring, viz., ethoxy, trityloxy, ferrocenyl(phenyl)methoxy, N,N-diethylamino, piperidino, and morpholino, is described. The spatial structure of diferrocenyl(morpholino)cyclopropenyl tetrafluoroborate was established based on the data from X-ray diffraction analysis. Under the action of potassium tert-butoxide, all the diferrocenylcyclopropenyl tetrafluoroborates undergo three-membered ring-opening with formation of the corresponding 2,3-diferrocenylacrylic acid derivatives. A mechanism of the ring-opening is suggested.

Full text of DOI:10.1016/j.jorganchem.2005.04.014

Journal of Organometallic Chemistry 690 (2005) 3333–3339
www.elsevier.com/locate/jorganchem
Diferrocenylcyclopropenyl cations. Synthesis, structures,
and some chemical properties
a,
Elena I. Klimova , Tatiana Klimova Berestneva , Simon Hernandez Ortega ,
a
b
*
´
Daniel Mendez Iturbide , Alfonso Garcıa Marquez , Marcos Martınez Garcıa
c
b
b
´
´
´
´
a
´
´
´
´
´
Facultad de Quımica, Universidad Nacional Autonoma de Mexico, Cd. Universitaria, Coyoacan, C.P. 04510, Mexico D.F., Mexico
´ ´ ´ ´ ´
Instituto de Quımica, Universidad Nacional Autonoma de Mexico, Cd. Universitaria, Coyoacan, C.P. 04510, Mexico D.F., Mexico
b
c
´
Departamento de Ciencias de la Salud, Universidad Autonoma de Tlaxcala, Av. Xicotencatl No 1,Tlaxcala, Tlaxcala, C.P. 90070, Mexico
Received 10 March 2005; accepted 5 April 2005
Available online 2 June 2005
Abstract
Synthesis of diferrocenylcyclopropenyl tetrafluoroborates with hetero-substituents in the three-membered ring, viz., ethoxy, tri-
tyloxy, ferrocenyl(phenyl)methoxy, N,N-diethylamino, piperidino, and morpholino, is described. The spatial structure of diferroce-
nyl(morpholino)cyclopropenyl tetrafluoroborate was established based on the data from X-ray diffraction analysis. Under the
action of potassium tert-butoxide, all the diferrocenylcyclopropenyl tetrafluoroborates undergo three-membered ring-opening with
formation of the corresponding 2,3-diferrocenylacrylic acid derivatives. A mechanism of the ring-opening is suggested.
Ó 2005 Elsevier B.V. All rights reserved.
Keywords: Ferrocene; Diferrocenylcyclopropenes; Diferrocenylcyclopropenyl tetrafluoroborates; Derivatives of 2,3-diferrocenylacrylic acid; Ring
opening; X-ray structural analysis
1. Introduction
Cyclopropenyl cations are the subject of many studies
in theoretical, physical, and synthetic organic chemistry
[4,5]. The possibility of the use of cyclopropenyl cations
in the synthesis of organic compounds with unusual
structural fragments accounts for the theoretical and
practical interest in these species [4].
The first syntheses of metallocenyl-substituted cyclo-
propenylium derivatives, viz., ferrocenyldiphenyl- and tri-
ferrocenylcyclopropenyl tetrachloroaluminates (1 and 2),
starting from tetrachlorocyclopropene were described in
1967 [6] and 1975 [7], respectively. Their reactions with
nucleophilic reagents afforded ferrocenyl-substituted
cyclopropenes (3–5) [8] (Scheme 1).
According to the Huckel rule [1], the cyclopropenyl
¨
cation represents the simplest aromatic system, this is
built of three carbon atoms with two p electrons delocal-
ized over three 2p orbitals. The first representative of
this class of compounds, viz., triphenylcyclopropenyl
tetrafluoroborate, was synthesized by Breslow in 1957
[2]. It manifested high thermodynamic stability; neither
ring-opening reactions typical of cyclopropane, viz.,
brominolysis or catalytic hydrogenolysis, nor addition
to the double bond typical of cyclopropenes, could be
effected. In 1959, VolÕpin et al. [3] reported the prepara-
tion of hydroxydiphenylcyclopenylium.
No detailed studies dealing with the preparation and
application of ferrocenylcyclopropenyl cations were car-
ried out. Hitherto, no ferrocenylcyclopropenylium with
hetero-substituents in the three-membered ring was
reported.
*
Corresponding author. Tel./fax: +52 55 5622 5371.
E-mail address: klimova@servidor.unam.mx (E.I. Klimova).
0022-328X/$ - see front matter Ó 2005 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2005.04.014

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E.I. Klimova et al. / Journal of Organometallic Chemistry 690 (2005) 3333–3339
Fc
Fc
Cl
Cl
PhH (AlCl )
1)
2)
FcH (AlCl3)
3
AlCl4
Ph
AlCl4
Fc
FcH (AlCl )
3
Ph
Fc
Cl
Cl
2
1
Nu
Fc
Nu
Fc
Nu
Fc
Nu
Nu
Fc
Fc
Ph
Ph
5
Ph
Fc
3
4
Fc= C5H5FeC5H4
Scheme 1.
NR2
In the present work, we describe synthesis of alkoxy-
and dialkylamino-diferrocenylcyclopropenyl cations and
studies of some of their chemical properties.
HNR2
BF4
Fc
7- 9
Fc
10-12
2. Results and discussion
NR2= Et2N
, (CH ) N
, O[(CH ) ] N
(11)
(10)
(12)
2 5
2 2 2
Diferrocenylcyclopropenone 6 easily obtainable by
alkylation of ferrocene with tetrachlorocyclopropene in
the presence of AlCl3 in ca. 90% yield [9] was used as
the starting compound for the preparation of hetero-
substituted diferrocenylcyclopropenyl tetrafluoroborates.
We have found that diferrocenylcyclopropenone 6 re-
acts with triethyloxonium, triphenylmethylium, and
ferrocenyl(phenyl)methylium tetrafluoroborates to give
crystalline alkoxy(diferrocenyl)cyclopropenylium tetra-
fluoroborates (7–9) (Scheme 2).
Scheme 3.
N,N-diethylamino- (10), piperidino- (11), and mor-
pholino-diferrocenylcyclopropenylium (12) tetrafluo-
roborates are red-violet crystalline compounds that are
storage-stable under ordinary conditions for a long
time. Their structures were determined based on the
data from 1H and 13C NMR spectra and elemental
analyses.
The spatial configuration of compound 12 was estab-
lished by X-ray diffraction analysis of a single crystal
prepared by crystallization from ethanol. The general
view of the molecule of diferrocenyl(morpholino)cyclo-
propenylium tetrafluoroborate 12 is shown in Fig.
1(a), the crystal packing, in Fig. 1(b), and selected bond
lengths and bond angles are listed in Table 1. The three-
membered ring in the structure 12 represents a virtually
equilateral triangle with the carbon–carbon bond
These dark violet salts are stable on storage in a dry
1
inert atmosphere, they are characterized by H and 13C
NMR spectra and data from elemental analyses.
In reactions with secondary amines, compounds 7–9
produce amino(diferrocenyl)cyclopropenylium tetraflu-
oroborates 10–12 (Scheme 3).
˚
lengths of 1.351–1.381 A and bond angles of 59.1–
˚
OTr
O
OEt
61.3°. The C(1)–N(1) bond length (d = 1.288(7) A) is
˚
Tr BF4
Et3O BF4
close to the C@N double bond length (d = 1.29 A)
BF4
Fc
BF4
Fc
[10,11], which suggests the considerable contribution
of the free electron pair on the nitrogen atom to the
delocalization of the positive charge of the three-mem-
bered ring. Hence, the equilibrium between the meso-
meric forms 12a and 12b is largely shifted towards the
iminium salt 12b (Scheme 4).
Fc
Fc
Fc
Fc
7
8
6
Fc(Ph)CH BF4
Tr= CPh3
OCH(Ph)Fc
The substituted cyclopentadienyl rings of the ferroce-
nyl fragments in compound 12 are coplanar with the
small ring, the ferrocenyl sandwiches are oppositely ori-
ented (Fig. 1(b)). The morpholine substituent has the
chair conformation. The Fe–C bond lengths and the
BF4
Fc
Fc
9
Scheme 2.

E.I. Klimova et al. / Journal of Organometallic Chemistry 690 (2005) 3333–3339
3335
Fig. 1. (a) Crystal structure of compound 12; (b) crystal packing of 12.
geometry of the ferrocene sandwiches are close to stan-
dard characteristics [10,12].
Apparently, the structures of cyclopropenylium tetra-
fluoroborates 7–11 are similar to those of compound 12
(Scheme 5).
This follows from the 13C NMR spectra of the cat-
ions 7–12, where the signals for the CipsoFc carbon
atoms resonate in a high-field region (d = 60–69 ppm),
which is uncommon for compounds of the ferrocene ser-
ies [9,11,13,14].

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E.I. Klimova et al. / Journal of Organometallic Chemistry 690 (2005) 3333–3339
Table 1
Selected bond lengths and bond angles for 12
H
H
O
X
O H
X
˚
Selected bond lengths, r (A)
Selected bond angles, x (°)
H2O
H
-
7- 12
C(1)–C(2)
C(1)–C(3)
C(2)–C(3)
C(1)–N(1)
C(24)–N(1)
C(27)–N(1)
C(2)–C(14)
C(4)–C(3)
B(1)–F(1)
1.381(8)
1.359(7)
1.351(8)
1.288(7)
1.497(8)
1.499(7)
1.464(8)
1.404(8)
1.375(16)
C(3)–C(1)–C(2)
C(3)–C(2)–C(1)
C(2)–C(3)–C(1)
N(1)–C(1)–C(3)
N(1)–C(1)–C(2)
C(1)–N(1)–C(24)
C(1)–N(1)–C(27)
C(3)–C(4)–C(5)
C(1)–C(3)–C(4)
59.1(4)
59.6(4)
61.3(4)
Fc
Fc
Fc
Fc
14a- f
150.4(6)
150.6(6)
122.8(5)
122.0(6)
126.6(6)
152.1(6)
Scheme 7.
O
H
X
O
HX
-
O
N
O
N
O
Fc
Fc
Fc
Fc
14a- f
6
N
BF4
Fc
BF4
BF4
Fc
Scheme 8.
Fc
Fc
Fc
Fc
12b
12a
12
Fc
Scheme 4.
H
X
O
X
Fc
13a- f
O
H
Fc
Fc
X
X
(7);
(8);
OCH(Fc)Ph
14a- f
15a- f
Scheme 9.
X= OEt
OTr
BF4
Fc
BF4
Fc
(9);
NEt2
(10);
N(CH2)5
Fc
Fc
(11);
N(CH2CH2)2O
7a- 11a
7b- 11b
(12);
To exclude the formation of cyclopropenone 6 one
should presumably employ nucleophiles, e.g., metal alk-
oxides, which would afford the intermediate addition
products 16a–f (Scheme 10).
Presumably, in this case it would be possible to iso-
late either the nucleophilic addition products (e.g., dif-
errocenylcyclopropenone ketals) or intramolecular
transformation products resulting from the small-ring
opening.
Scheme 5.
Studies of the chemical properties of the salts 7–12 re-
vealed, that upon contact with water or moist solvents
(on heating) they decompose to form 2,3-diferrocenylcy-
clopropene 6 (60–70%) together with the corresponding
2,3-diferrocenylacrylic acid derivatives 13a–f (8–10%)
(Scheme 6).
In our opinion, this reaction involves the nucleophilic
addition of water to the electron-deficient carbon atom
of the three-membered ring bearing the heteroatom to
afford unstable addition products 14a–f (Scheme 7).
These undergo intramolecular transformations with
retention of the small ring leading to cyclopropenone 6
(Scheme 8) or with small-ring opening into carbenoid
intermediates 15a–f resulting in 2,3-diferrocenylacrylic
acid derivatives 13a–f (Scheme 9).
To check this assumption, we studied the reactions of
the salts 7–12 with potassium tert-butoxide. It was
found that the reactions occur with evolution of isobu-
tylene (this followed from decoloration of bromine
water and appearance of heavy oil droplets) and forma-
tion of the corresponding 2,3-diferrocenylacrylates and
-acrylamides 13a–f in high yields (Scheme 11).
1
According to the data from H and 13C NMR spec-
troscopy, these derivatives were formed as single
geometrical isomers, presumably, with cis-arranged
ferrocenyl groups, which is in keeping with the spatial
Fc
O
R
X
O
FcCH
H2O
RO M
7- 12
+
O
7-12
X
Fc
Fc
13a- f
6
Fc
Fc
= OEt (a), OTr (b), OCH(Ph)Fc (c), NEt2 (d), N(CH2)5 (e), N[(CH2)2]2O (f)
16a- f
Scheme 6.
Scheme 10.

E.I. Klimova et al. / Journal of Organometallic Chemistry 690 (2005) 3333–3339
3337
Fc
X
CH3
C
CH3
X
O
Fc
CH3
CH3
t-BuO K
CH3
O
CH2
13a- f
7- 12
+
H
CH3
Fc
Fc
17a- f
CH3
16a- f
Scheme 11.
Table 2
Crystal data, data collection and refinement parameters for 12
orientation of the ferrocenyl sandwiches in the molecule
of isopropyl 2,3-diferrocenylacrylate [9]. However, we
could not obtain crystals of compounds 13a–f suitable
for unambiguous determination of their absolute config-
urations by X-ray diffraction analysis.
Data
12
Molecular formula
Formula weight (g molÀ1
Temperature (K)
Crystal system
C
579.00
27H26BF4Fe2NO
)
291(2)
Orthorhombic
Space group
˚
P21212
14.721(1)
3. Experimental
a (A)
˚
b (A)
˚
c (A)
24.683(2)
7.6412(6)
All the solvents were dried according to standard pro-
cedures [14] and were freshly distilled before use. Col-
umn chromatography was carried out on alumina
(Brockmann activity III). The 1H and 13C NMR spectra
of the tetrafluoroborates 7–12 were recorded on a Unity
Inova Varian spectrometer (300 and 75 MHz) for solu-
tions in CD2Cl2 with Me4Si as the internal standard.
a (°)
b (°)
c (°)
90.0
90.0
90.0
2776.4(4)
3
˚
V (A )
Z
4
1.385
Dcalc(Mg mmÀ3
)
Absorption coefficient (mmÀ1
F(0 0 0)
)
1.091
1184
1
The H and 13C NMR spectra of the compounds 13a–
˚
Radiation, k (A)
Monochromator
Mo Ka, 0.71073
Graphite
2.67–25.00
f were recorded for solutions in CDCl3. An Elemental
Analysis System GmbH was used for elemental analy-
ses. Mass spectra (EI, 70 eV) were obtained on a Varian
MAT CH-6 mass spectrometer. The unit cell parameters
and the X-ray diffraction intensities were recorded on a
Bruker Smart Apex CCD area detector/x diffractome-
ter. The crystallographic data, parameters of the X-ray
experiment, and refinements for 12 are listed in Table 2.
Diferrocenylcyclopropenone 6 was prepared by alkyl-
ation of ferrocene with tetrachlorocyclopropene in the
presence of AlCl3 [9]; ferrocenyl(phenyl)methylium tet-
rafluoroborate was obtained by treatment of ferro-
cenyl(phenyl)methanol with tetrafluoroboric acid
etherate [13,14].
The following reagents were purchased from
Aldrich: ferrocene, 98%; aluminum chloride, 99.99%;
tetrachlorocyclopropene, 98%; triethyloxonium tetra-
fluoroborate, 1.0 M solution in dichloromethane;
triphenylcarbenium tetrafluoroborate; diethylamine,
99.5%; piperidine, 99%; morpholine, 99+%; potassium
tert-butoxide, 95%. Tetrafluoroboric acid etherate (50–
52%) was purchased from Alfa AESAR.
h Range (°)
Reflections collected
Reflections independent
Rint
22,796
4879
0.0653
Final R indices [I > 2r(I)]
R indices (all data)
Data/restraints/parameters
Refinement method
Goodness-of-fit
R1 = 0.0485, wR2 = 0.1095
R1 = 0.0744, wR2 = 0.1149
6373/0/479
Full-matrix-least-squares on F2
0.943
À0.280/0.566
Minimum/maximum reÀsi3dual
˚
electron density (e A
)
(50 ml). Stirring was continued for 2 h and dry diethyl
ether (100 ml) was added. The violet precipitate was fil-
tered off, washed with dry ether, and dried in vacuo. The
yield of the title compound was 0.88 g (82%), m.p. 209–
211 °C; MS m/z (%): 538 (71), 452 (100); dH (300 MHz,
CD2Cl2): 2.96 (3H, t, J = 7.2 Hz, CH3), 6.12 (10H, s,
2C5H5), 6.48 (2H, q, J = 7.2 Hz, CH2), 6.62 (4H, m,
C5H4), 6.83 (4H, m, C5H4). Found: C, 55.73; H, 4.50;
F, 14.09; Fe, 20.93%. Calc. for C25H23BF4Fe2O: C,
55.81; H, 4.31; F, 14.13; Fe, 20.77.
3.1. Ethoxy(diferrocenyl)cyclopropenylium
tetrafluoroborate (7)
3.2. Diferrocenyl(trityloxy)cyclopropenylium
tetrafluoroborate (8)
Triethyloxonium tetrafluoroborate (1.0 M solution in
dichloromethane, 5 mmol) was added in a dry inert
atmosphere with stirring to a solution of diferrocenyl-
cyclopropenone 6 (0.85 g, 2 mmol) in dichloromethane
A solution of triphenylcarbenium tetrafluoroborate
(0.99 g, 3 mmol) in CH2Cl2 (20 ml) was added to a solu-
tion of diferrocenylcyclopropenone 6 (0.85 g, 2 mmol) in

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E.I. Klimova et al. / Journal of Organometallic Chemistry 690 (2005) 3333–3339
dichloromethane (50 ml). The mixture was stirred in an
atmosphere of dry nitrogen for 1 h at 20 °C and dry
diethyl ether (100 ml) was added. The precipitate was fil-
tered off, washed with dry ether, and dried in vacuo. The
yield of the title compound was 1.3 g (85%), violet crys-
tals, m.p. 314–317 °C; MS m/z (%): 752 (68), 666 (98); dH
(300 MHz, CD2Cl2): 5.66 (10H, s, 2C5H5), 6.42 (4H, m,
C5H4), 6.53 (4H, m, C5H4), 7.38–7.99 (15H, m, 3Ph).
Found: C, 66.84; H, 4.49; F, 10.25; Fe, 15.01%. Calc.
for C42H33BF4Fe2O: C, 87.06; H, 4.42; F, 10.10; Fe,
14.85.
577 (89), 491 (100); dH (300 MHz, CD2Cl2): 1.76 (2H,
m, CH2), 2.75 (2H, m, CH2), 2.95–3.41 (4H, m,
2CH2), 3.64 (2H, m, CH2), 4.26 (10H, s, 2C5H5), 4.31
(2H, m, C5H4), 4.49 (2H, m, C5H4), 4.69 (2H, m,
C5H4), 4.87 (2H, m, C5H4); dC (75 MHz, CD2Cl2):
30.87, 43.58, 48.93 (5CH2), 60.31 (2CipsoFc), 70.72
(2C5H5), 71.68, 74.20 (2C5H4), 130.19 (2C), 138.89 (C–
N). Found: C, 58.44; H, 4.68; F, 13.29; Fe, 19.18; N,
2.59%. Calc. for C28H28BF4Fe2N: C, 58.28; H, 4.89; F,
13.17; Fe, 19.36; N, 2.43.
3.6. Diferrocenyl(morpholino)cyclopropenylium
tetrafluoroborate (12)
3.3. Diferrocenyl(ferrocenyl(phenyl)methoxy)-
cyclopropenylium tetrafluoroborate (9)
The title compound was obtained analogously, yield
78%, red-violet crystals, m.p. 210–212 °C; MS m/z (%):
579 (82), 493 (100); dH (300 MHz, CD2Cl2): 3.91(4H,
m, 2CH2), 3.99 (4H, m, 2CH2), 4.37 (10H, s, 2C5H5),
4.87 (4H, m, C5H4), 4.91 (4H, m, C5H4); dC (75 MHz,
CD2Cl2): 51.97, 66.61 (4CH2), 60.61 (2CipsoFc), 71.42
(2C5H5), 72.23, 75.23 (2C5H4), 132.51 (2C), 139.47 (C–
N). Found: C, 55.86; H, 4.68; F, 13.24; Fe, 19.40; N,
2.34%. Calc. for C27H26BF4Fe2NO: C, 56.01; H, 4.53;
F, 13.12; Fe, 19.29; N, 2.42.
Analogously, the reaction of diferrocenylcycloprope-
none 6 (0.42 g, 1 mmol) in CH2Cl2 (30 ml) with ferro-
cenyl(phenyl)methylium
tetrafluoroborate
(0.54 g,
1.5 mmol) in dichloromethane (25 ml) (1 h, 20 °C) affor-
ded the title salt, yield 0.61 g (81%), dark violet crystals,
m.p. 323–325 °C; MS m/z (%): 784 (74), 698 (96); dH
(300 MHz, CD2Cl2): 4.28 (5H, s, C5H5), 4.65 (2H, m,
C5H4), 5.43 (10H, s, 2C5H5), 4.76 (2H, m, C5H4), 6.36
(4H, m, C5H4), 6.44 (4H, m, C5H4), 5.62 (1H, s, CH),
7.15–7.48 (5H, m, Ph). Found: C, 61.38; H, 4.13; F,
9.52; Fe, 21.49%. Calc. for C40H33BF4Fe3O: C, 61.27;
H, 4.24; F, 9.70; Fe, 21.37.
3.7. Ethyl 2,3-diferrocenylacrylate (13a)
A stirring mixture of salt 7 (0.54 g, 1 mmol) and t-
BuOK (0.22 g, 2.2 mmol) in dry benzene (50 ml) was
boiled under reflux in an inert dry atmosphere for
3 h. The solvent was evaporated and the residue was
chromatographed on alumina (hexane–ether, 4:1) to
yield 0.33 g (70%) of the title compound, red powder,
m.p. 141–142 °C; MS m/z (%): 468 (100); dH
(300 MHz, CDCl3): 1.47 (3H, t, J = 7.2 Hz, CH3),
4.06 (5H, s, C5H5), 4.07 (5H, s, C5H5), 4.21 (2H, m,
C5H4), 4.24 (4H, m, C5H4), 4.36 (2H, q, J = 7.2 Hz,
CH2), 4.47 (2H, m, C5H4), 7.28 (1H, s, CH@); dC
(75 MHz, CDCl3): 14.47 (CH3), 60.45 (CH2), 69.47,
69.66 (2C5H5), 70.56, 71.24, 71.32, 71.89 (2C5H4),
79.72, 82.20 (2CipsoFc), 136.74 (CH@), 126.77 (–C@),
167.51 (C@O). Found: C, 64.29; H, 5.23; Fe,
24.06%. Calc. for C25H24Fe2O2: C, 64.14; H, 5.17;
Fe, 23.86.
3.4. N,N-diethylamino(diferrocenyl)cyclopropenylium
tetrafluoroborate (10)
Diethylamine (3.0 ml) was added drop wise to a solu-
tion of salt 7 (0.54 g, 1 mmol) in dichloromethane
(50 ml) and the mixture was stirred for 2 h at 20 °C in
an inert atmosphere. Then dry ethanol (100 ml) was
added, the mixture was stirred for 30 min, concentrated
in vacuo to 30 ml, and left overnight at 20 °C. The pre-
cipitate that formed was filtered off, washed with dry
ethanol, and dried in a vacuum desiccator over P2O5.
The yield of the title compound was 0.37 g (74%), red-
violet crystals, m.p. 182–184 °C; MS m/z (%): 565 (86),
479 (100); dH (300 MHz, CD2Cl2): 1.50 (6H, t,
J = 7.2 Hz, 2CH3), 3.84 (4H, q, J = 7.2 Hz, 2CH2),
4.35 (10H, s, 2C5H5), 4.83 (4H, m, C5H4), 4.90 (4H,
m, C5H4); dC (75 MHz, CD2Cl2): 14.62 (2CH3), 49.04
(2CH2), 60.45 (2CipsoFc), 70.82 (2C5H5), 71.81, 74.39
(2C5H4), 132.04 (2C), 139.40 (C–N). Found: C, 57.54;
H, 4.73; F, 13.61; Fe, 19.63; N, 2.52%. Calc. for
C27H28BF4Fe2N: C, 57.39; H, 5.00; F, 13.45; Fe,
19.77; N, 2.48.
3.8. Triphenylmethyl 2,3-diferrocenylacrylate (13b)
This compound was obtained analogously, yield
68%, brown powder, m.p. 173–175 °C; MS m/z (%):
682 (100); dH (300 MHz, CDCl3): 4.09 (5H, s,
C5H5), 4.13 (5H, s, C5H5), 4.28 (2H, m, C5H4), 4.36
(2H, m, C5H4), 4.48 (2H, m, C5H4), 4.59 (2H, m,
C5H4), 7.89 (1H, s, CH@), 7.01–7.15 (3H, m), 7.32–
7.64 (12H, m, 3Ph). Found: C, 74.09; H, 4.88; Fe,
16.48%. Calc. for C42H34Fe2O2: C, 73.92; H, 5.02;
Fe, 16.37.
3.5. Diferrocenyl(piperidino)cyclopropenylium
tetrafluoroborate (11)
The title compound was obtained analogously, yield
77%, red-violet crystals, m.p. 204–205 °C; MS m/z (%):

E.I. Klimova et al. / Journal of Organometallic Chemistry 690 (2005) 3333–3339
3339
3.9. Ferrocenyl(phenyl)methyl 2,3-diferrocenylacrylate
(13c)
128.06 (CH@), 130.57 (C), 170.35 (C@O). Found: C,
63.78; H, 5.44; Fe, 22.07; N, 2.63%. Calc. for C27H27Fe2-
NO2: C, 63.68; H, 5.35; Fe, 21.93; N, 2.75.
The title compound was obtained as described for the
synthesis of 13a, yield 0.50 g (70%), dark red fine crystal-
line powder, m.p. 213–215 °C; MS m/z (%): 714 (100);
dH (300 MHz, CDCl3): 4.02 (1H, s, CH), 4. 08 (5H, s,
C5H5), 4.12 (5H, s, C5H5), 4.19 (5H, s, C5H5), 4.22
(4H, m, C5H4), 4.27 (2H, m, C5H4), 4.35 (2H, m,
C5H4), 4.38 (2H, m, C5H4), 4.42 (2H, m, C5H4), 7.16
(1H, s, CH@), 7.19–7.38 (5H, m, Ph). Found: C,
67.39; H, 4.63; Fe, 23.61%. Calc. for C40H34Fe3O2: C,
67.27; H, 4.80; Fe, 23.46.
4. Supplementary material
Crystallographic data for the structural analysis have
been deposited with the Cambridge Crystallographic
Data Centre, CCDC No. 264421 for compound 12.
Copies of this information may be obtained free of charge
from The Director, CCDC, 12 Union Road, Cambridge
CB2 IEZ, UK (fax: +44 1223 336033; e-mail: deposit@
ccdc.cam.ac.uk or http://www.ccdc.cam.ac.uk).
3.10. N,N-diethyl 2,3-diferrocenylacrylamide (13d)
Yield 65%, orange powder, m.p. 171–172 °C; MS
m/z (%): 495 (100); dH (300 MHz, CDCl3): 1.30 (6H,
t, J = 7.2 Hz, 2CH3), 4.08 (5H, s, C5H5), 4.14 (5H,
s, C5H5), 4.17 (2H, m, C5H4), 4.20 (4H, m, C5H4),
4.27 (4H, q, J = 7.2 Hz, 2CH2), 4.49 (2H, m, C5H4),
6.29 (1H, s, CH@); dC (75 MHz, CDCl3): 12.97,
14.23 (2CH3), 38.54, 43.24 (2CH2), 69.07, 69.32
(2C5H5), 68.03, 68.55, 69.04, 69.65 (2C5H4), 80.59,
80.79 (2CipsoFc), 126.27 (CH@),132.57 (C), 171.02
(C@O). Found: C, 65.35; H, 6.07; Fe, 22.69; N,
2.76%. Calc. for C27H29Fe2NO: C, 65.48; H, 5.91;
Fe, 22.56; N, 2.82.
Acknowledgments
This work was supported by the grant CONACyT
´
(Mexico). Thanks are due to Eduardo Arturo Vazquez
Lopez and Rosa Isela Del Villar Morales for their tech-
´
nical assistance.
References
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3.11. N-(2,3-diferrocenylacryloyl)piperidine (13e)
Yield 70%, dark red powder, m.p. 159–160 °C; MS
m/z (%): 507 (100); dH (300 MHz, CDCl3): 1.69 (6H,
m, 3CH2), 3.44 (2H, m, CH2), 3.78 (2H, m, CH2), 4.09
(5H, s, C5H5), 4.13 (5H, s, C5H5), 4.16 (2H, m, C5H4),
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C5H4), 6.27 (1H, s, CH@); dC (75 MHz, CDCl3):
24.67, 25.64, 26.36, 42.24, 48.60 (5CH2), 69.05, 69.28
(2C5H5), 68.60, 68.65, 69.30, 69.68 (2C5H4), 80.43,
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(C@O). Found: C, 66.17; H, 5.93; Fe, 21.86; N, 2.69%.
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Yield 77%, red-brown powder, m.p. 190–192 °C; MS
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2CH2), 3.82 (4H, m, 2CH2), 4.08 (5H, s, C5H5), 4.14
(5H, s, C5H5), 4.19 (6H, m, C5H4), 4.25 (2H, m,
C5H4), 6.28 (1H, s, CH@); dC (75 MHz, CDCl3): 49.04
(2CH2), 66.87 (2CH2), 69.15, 69.34 (2C5H5), 68.88,
69.17, 69.75, 69.92 (2C5H4), 80.05, 80.26 (2CipsoFc),
´ ´
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´ ´
[14] V.N. Postnov, E.I. Klimova, M. Martınez Garcıa, N.N. Meles-
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