Synthesis, structures and some chemical and electrochemical properties of E-1,2-diferrocenyl-3-methylthioprop-2-enone and its ketals

Article abstract of DOI:10.1016/j.jorganchem.2006.02.024

2,3-Diferrocenyl-1-methylthiocyclopropenylium iodide reacts with water, metal alkoxides, phenolates and with alcohols in the presence of Et₃N to give E-1,2-diferrocenyl-3-methylthioprop-2-enone or its ketals. Their structures were established b

Full text of DOI:10.1016/j.jorganchem.2006.02.024

Journal of Organometallic Chemistry 691 (2006) 2872–2882
www.elsevier.com/locate/jorganchem
Synthesis, structures and some chemical and electrochemical
properties of E-1,2-diferrocenyl-3-methylthioprop-2-enone and its ketals
a,
b
a
*
Tatiana Klimova Berestneva , Marcos Mart ´ı nez Garc ´ı a , Luis Ortiz-Frade ,
b
b
a
Simon Hern a´ ndez Ortega , Ruben A. Toscano , Elena Klimova
a
Facultad de Qu ı´ mica, Universidad Nacional Aut o´ noma de M e´ xico, Cd. Universitaria, Coyoac a´ n, C.P. 04510, M e´ xico D.F., Mexico
Instituto de Qu ı´ mica, Universidad Nacional Aut o´ noma de M e´ xico, Cd. Universitaria, Coyoac a´ n, C.P. 04510, M e´ xico D.F., Mexico
b
Received 7 December 2005; received in revised form 20 February 2006; accepted 21 February 2006
Available online 28 February 2006
Abstract
,3-Diferrocenyl-1-methylthiocyclopropenylium iodide reacts with water, metal alkoxides, phenolates and with alcohols in the pres-
2
1
3
ence of Et N to give E-1,2-diferrocenyl-3-methylthioprop-2-enone or its ketals. Their structures were established based on data from H
and C NMR spectroscopy and X-ray diffraction analysis. The mechanistic aspects of these reactions are discussed. Electrochemical
1
3
properties of 8 and 13b have been studied. The compounds present two oxidation processes (I–II), attributed to the oxidations of the
0
0
0
0
0
0
ferrocenes groups, E (I), E (II), DE (II–I) and comproportionation constant Kcom are reported.
2006 Elsevier B.V. All rights reserved.
ꢀ
Keywords: Ferrocene; Diferrocenyl(methylthio)cyclopropenilium; 3,3-Dimethylthio-cyclopropene; 1,2-Diferrocenyl-3-methylthioprop-2-enone; Three-
membered ring opening
1
. Introduction
Diferrocenylcyclopropenylium cations with heterosub-
stituents in the small ring have recently been described
[8–10]. These include 1-ethoxy-, 1-diethylamino-, 1-mor-
pholino-, 1-piperidino-2,3-diferrocenylcyclopropenylium
tetrafluoroborates (4a-d) and 2,3-diferrocenyl-1-methyl-
thiocyclopropenylium iodide (4e). Their chemical pro-
perties are being currently investigated. Thus, it was
established that the tetrafluoroborate (4a) reacts with
organolithium compounds to yield 3,3-dialkyl-1,2-di-
ferrocenylcyclopropenes (5a,b) [8] (Scheme 3).
Analogous compounds (5a,c–e) are obtained in low
yields (ꢀ10–20%) in reactions of the iodide (4e) with RLi
and RMgX, the major products being diferrocenyl-substi-
tuted (methylthio)polyenes (6a,c–e) (ꢀ60–70%) [10]
(Scheme 4).
It is well known, that one of the basic reactions of carb-
ocations is the cation–anion combination reaction [1,2].
Thus, the reactions of cyclopropenylium cation (1a) with
various carbon nucleophiles (RMgX, RLi, R Cd) result
2
in high yields (ꢀ70–95%) of the corresponding 3,3-disubsti-
tuted cyclopropenes (2a) and (2b) [2–4] (Scheme 1).
At the same time, the Grignard reaction of 1-methyl-
thio-substituted cyclopropenylium cation (1b) involves the
attack of the anionic reagents at the carbon atom bearing
the phenyl group to give 1-methylthiocycloprop-1-ene
derivatives (2c) [5–7], which afford metylthio-substituted
indene derivatives (3) in good yields upon thermolysis
(
Scheme 2).
Thus, the nucleophilic attacks of the anionic reagents on
2,3-diferrocenyl-1-methylthiocyclopropenylium iodide (4e)
are directed at both C-1 and C-2 centers of the three-
carbon ring, which allows the use of di(ferrocenyl)alkyl-
thiocyclopropenyl cations as the starting material for the
preparation of different classes of diferrocenyl-containing
*
Corresponding author. Tel./fax: +52 55 56225371.
E-mail address: klimova@servidor.unam.mx (T.K. Berestneva).
0
022-328X/$ - see front matter ꢀ 2006 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2006.02.024

T.K. Berestneva et al. / Journal of Organometallic Chemistry 691 (2006) 2872–2882
2873
R1
2. Results and discussion
R1
R2
Ph
R2
R M
2
X
2
,3-Diferrocenyl-1-methylthiocyclopropenylium iodide
+
4
e was prepared [10] starting from 2,3-diferrocenylcyclop-
ropenone according to Scheme 5.
Ph
Ph
Ph
Ph
Ph
R1
1
a
2
a
2b
This is sedimented as a red-violet precipitate upon treat-
ment of a solution of cyclopropenethione (7a) in benzene
R = Ph, Me, Pri
Fc = C H FeC H
M = Li, Mg
R = Ph, Me, Fc
2
1
13
with methyl iodide, its H and C NMR spectroscopic
characteristics are given in the Experimental section. The
iodide 4e is stable when stored in a dry inert atmosphere.
In a contact with water or moist solvents this is trans-
formed into 2,3-diferrocenylcyclopropenone 7, 1,2-diferro-
cenyl-3-methylthioprop-2-enone (8) as a single geometric
isomer, presumably with E-configuration, 2,3-diferroce-
nyl-1,1-dimethylthiocyclopropene (9) and 1,2-diferroce-
nyl-1,1,3-trimethylthio-2-propene (10) (Scheme 6).
1
5
5
5
4
Scheme 1.
SMe
Ph
R
RMgBr
X
Ph
Ph
Ph
SMe
The structure of this enone 8 was established based on
1
b
2c
1
13
the data from H and C NMR spectra and X-ray diffrac-
1
tion analysis. Thus, the H NMR spectrum contained sig-
R
nals for two ferrocenyl substituents, a signal for the
methyl group, and one signal for the olefinic proton. The
1
3
Ph
presence in the C NMR spectrum of compound 8 of sig-
nals for one methyl group, two ferrocenyl fragments, one
CH@ and C@O groups, and two CipsoFc carbon atoms cor-
roborates completely the suggested structure. X-ray diffrac-
tion analysis of a single crystal of compound 8 obtained by
crystallization from CH Cl allowed elucidation of its spa-
SMe
3
Scheme 2.
2
2
tial structure. The general view of the molecule 8 is shown
in Fig. 1a and the crystal packing is shown in Fig. 1b.
Selected bond lengths and bond angles are given in the leg-
ends to these figures.
OEt
R
R
RLi
BF4
Fc
A tentative mechanism of this transformation is outlined
in Scheme 7. The nucleophilic attack by water on the C-1
and C-2 atoms of the three-membered ring results in
an unstable intermediate addition products, viz., 2,3-di-
ferrocenyl-1-hydroxy-1-methylthio- and 2,3-diferrocenyl-3-
hydroxy-1-methylthiocyclopropenes A and B, respectively.
Intramolecular transformation of A affords diferrocenyl-
cyclopropenone 7 and methanethiol, intramolecular trans-
formation of B occurs with opening of the small ring into a
carbenoid intermediate C and results in the final enone 8.
The methanethiol molecule as a nucleophile attack on the
carbon atoms C-1 and C-2 of the iodide 4e results in the
dimethylthiocyclopropene 9 and dithioketal 10 (Scheme 7).
We also found that diferrocenylpropenone 8 also
formed upon reaction of the iodide 4e with metal alkoxides
derived from alcohols containing a b hydrogen atom. The
alkoxides tested comprised potassium tert-butoxide,
sodium ethoxide, lithium 1-ferrocenylethoxide, and lithium
Fc
Fc
Fc
4
a
5a,b
n
R = Me (a); Bu (b)
Scheme 3.
R
Fc
C
SMe
Fc
SMe
R
C
C
C
RCH2M
I
+
H
R
H
Fc
Fc
Fc
Fc
4
e
5a,c-e
6a,c-e
R = H (a); Me (c); Ph (d); CH=CH (e)
2
M = Li, Mg
Scheme 4.
1-ferrocenylisobutoxide (Scheme 8 and 9).
compounds both with retention of the alkylthio-substitu-
ents and devoid of them.
In all cases, compound 8 was isolated in high yields
(ꢀ75–90%). In addition to the enone 8, each reaction affor-
ded the corresponding olefins (11a–d). The evolution of gas-
eous isobutylene 11a and ethylene 11b (Scheme 8) was
proved by identification of the respective dibromides, which
were obtained upon passing the evolving gases through bro-
mine water. Vinylferrocene 11c and isopropenylferrocene
In the present work, we studied the reactions of 2,3-di-
ferrocenyl-1-methylthiocyclopropenylium iodide (4e) with
water, metal alkoxides and aryloxides, and alcohols and
investigated some chemical and electrochemical properties
of the reaction products.

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T.K. Berestneva et al. / Journal of Organometallic Chemistry 691 (2006) 2872–2882
O
OEt
SMe
S
HN
N
NaHS
Et O BF
MeI
3
4
BF4
BF4
I
Fc
Fc
Fc
Fc
Fc
Fc
Fc
Fc
Fc
Fc
4
a
4d
7a
4e
7
Scheme 5.
Fc
C
SMe
MeS
SMe
Fc
SMe
SMe
H O / C H
2
6
6
C
I
Fc
Fc
C
C
+
C
O
H
7 +
+
C
H
MeS
SMe
10
Fc
Fc
Fc
Fc
4
e
9
8
(E)
Scheme 6.
˚
Fig. 1. Molecular structure of 8. Selected bond lengths (A): C(1)–C(4) = 1.472(2), C(1)–O(1) = 1.217(2), C(1)–C(2) = 1.497(2), C(2)–C(3) = 1.340(2),
C(3)–S(1) = 1.7288(18), S(1)–C(24) = 1.789(2), C(2)–C(14) = 1.472(2), C(4)–C(5) = 1.427(3), C(14)–C(15) = 1.423(3). Selected bond angles (ꢁ): C(4)–
C(1)–C(2) = 117.39(16), C(1)–C(2)–C(3) = 115.17(15), C(2)–C(3)–S(1) = 127.11(14), C(3)–S(1)–C(24) = 100.44(10), O(1)–C(1)–C(2) = 121.19(17), O(1)–
C(1)–C(4) = 121.39(17), C(1)–C(2)–C(14) = 117.06(15); C(1)–C(4)–C(5) = 127.42(17).
1
1d were isolated in individual states by chromatography,
ide and sodium benzyloxide form ketals (13a) and (13b),
respectively (Scheme 11).
1
their m.p.’s and H NMR spectroscopic characteristics
coincided with the literature data [11,12].
A tentative mechanism of the reaction of the salt 4e with
metal alkoxides (Scheme 10) should include intramolecular
transformations of carbene-like intermediates (12a–d)
The structures of the ketals 13a and 13b were established
1
13
based on the data from H and C NMR spectroscopy,
1
and X-ray analysis (for 13b). The H MMR spectrum of
compound 13a contained two singlets for the protons of
three methyl groups in a ratio 1:2, one singlet for the ole-
finic proton and signals for the protons of the ferrocenyl
substituents. There were one singlet for the methyl group,
one singlet for the protons of two methylene groups and
(
Scheme 10).
Metal alkoxides derived from alcohols devoid of b
hydrogen atoms react with the iodide 4e only in the pres-
ence of the corresponding alcohols. Thus, sodium methox-

T.K. Berestneva et al. / Journal of Organometallic Chemistry 691 (2006) 2872–2882
2875
MeS
O
H
+
4e
7
+
MeSH
9
10
+
Fc
Fc
SMe
A
H O
2
I
SMe
Fc
C
Fc
Fc
Fc
SMe
4e
SMe
C C
Fc
OH
Fc
Fc
C
C
O
H
O
H
Fc
B
C
8 (E)
Scheme 7.
tBuOK
NMR spectroscopic data suggested that these ketals
CH3
CH3
8
8
+
+
C
CH2
represented single geometric isomers. The results of X-ray
diffraction analysis of a single crystal of compound 13b
obtained by crystallization from chloroform show that
the double bond in this ketal has E configuration. Presum-
ably, this holds for compound 13a as well. The general view
of the molecule 13b is shown in Fig. 2a and the crystal
packing is shown in Fig. 2b. Selected bond lengths and
bond angles are given in the legends to these figures.
11a
4e
EtONa
CH2 CH2
1
1b
Scheme 8.
C H
6
6
Fc CH CH3
OLi
4
e
+
8
8
+
Fc CH CH2
11c
OMe Fc
SMe
CH3
C H
6 6
+
C H
6 6
MeOH
BnOH
Fc
C
C
C
Fc
C
CH2
4
e
+ Fc
C
CH3
+
4e
CH ONa
3
+
H
CH3
1d
OMe
OLi
13a (E)
1
PhCH O
2
Fc
C
Scheme 9.
+
SMe
C H
6
6
Fc
C
C
4e
+ PhCH2ONa
H
signals for the protons of two ferrocenyl and two phenyl
PhCH2O
1
13b (E)
substituents in the H NMR spectrum of the ketal 13b.
1
3
C NMR spectra of the ketals 13a and 13b corroborate
Scheme 11.
completely their structures.
SMe
I
SMe
R
H
R
H
O
C
C R2
O
C
C R2
R2
R1
R2
Fc
Fc
R1
Fc
Fc
4e
Fc
9b
C
SMe
Fc
R
R2
R2
C
O
C
C
C
8
+
R1
H
C
C
R
R2
11a-d
R1 R2
12a-d
R= R = CH , R = H (a); R = R = R = H (b); R= R = H, R = Fc (c); R= H, R = Fc, R = CH (d)
1
3
2
1
2
2
1
1
2
3
Scheme 10.

2876
T.K. Berestneva et al. / Journal of Organometallic Chemistry 691 (2006) 2872–2882
(
a)
(
b)
˚
Fig. 2. (a) Molecular structure of 13b. Selected bond lengths (A): C(1)–O(1) = 1.414(2), C(1)–O(2) = 1.419(2), O(1)–C(5) = 1.427(2), C(12)–
O(2) = 1.440(2), C(1)–C(2) = 1.544(3), C(2)–C(29) = 1.485(3), C(2)–C(3) = 1.331(3), S(1)–C(3) = 1.739(2), S(1)–C(4) = 1.791(2). Selected bond angles
(
ꢁ): C(4)–S(1)–C(3) = 99.94(11), S(1)–C(3)–C(2) = 128.13(17), C(3)–C(2)–C(1) = 117.87(17), C(2)–C(1)–O(2) = 106.79(15), C(2)–C(1)–O(1) = 112.25(15),
C(1)–O(1)–C(5) = 114.29(14), C(1)–O(2)–C(12) = 116.07(14). (b) Crystal packing of 13b.
The reactions of the iodide 4e with metal phenolates
occur analogously. Thus, sodium p-cresolate opens the
three-membered ring to give compound 13c (Scheme 12).
It was found further that di(ferrocenyl)methylthiocyclo-
propenylium iodide 4e reacted with various alcohols in the
presence of triethylamine (Scheme 13).
In these cases, the reactions seem to follow the mecha-
nisms involving intermolecular transformations of car-
bene-like intermediates (14a–c) and (12a–d) (Scheme 14).
Compounds 8 and 13a–c were found to react with
hydrazine hydrate on heating to yield 3,4-diferrocenylpy-
razole (15) (Scheme 15).

T.K. Berestneva et al. / Journal of Organometallic Chemistry 691 (2006) 2872–2882
2877
CH3
O
Fc
C
SMe
+
C H EtOH
6
6
Fc
C
C
4
e
+ CH3
ONa
O
H
CH3
1
3c (E)
Scheme 12.
SMe
tBuOH, EtOH
MeOH, BnOH, ArOH
Et3N
I
13a-c
8
+ Olefins
Et N
3
Fc
Fc
4e
Scheme 13.
SMe
4e +
RO M (or ROH + Et N)
3
OR
Fc
Fc
9c
Fc
Fc
C
SMe
RO
Fc
Fc
C
SMe
C
C
13a-c
C
C
OR
H O R
OR
H
15a-c
14a-c
R = Me (a); R = Bn (b); R = p-CH C H (c)
3
6 4
Scheme 14.
ꢁ
3
ꢁ3
Fc
H
Fc
a 1.0 · 10 mol dm solution of each compound in sup-
porting electrolyte (0.1 M TBABF4 in acetonitrile) was
used. Fig. 3 shows a typical voltammogram of compound
8 obtained in a platinum electrode. When the potential
scan was initiated in the positive direction, two oxidation
signals (I and II ) were observed, and when the potential
N
8
, 13a-c
H N NH
2
+
2
N
H
1
6
a
a
scan was reversed E+k two reduction signals (I and II )
c
c
Scheme 15.
were detected. On the other hand, when the potential scan
was started in the negative direction, the same behaviour is
presented. The independence of the oxidation signals (Ia
Its structure was established based on the data from ele-
1
13
mental analysis and H and C NMR spectroscopy.
Thus, di(ferrocenyl)methylthiocyclopropenylium iodide
reacts with O-nucleophiles in a stereospecific manner to
give the three-membered ring-opening products, viz.,
propenone and its ketals, with trisubstituted E olefinic
fragments.
and II ) was established by modifying the switching poten-
a
tials (E+k). Each oxidation signal has, respectively, a corre-
sponding reduction signal (I and II ).
c
c
The anodic peak potential value E (I) obtained for sig-
pa
+
nal I was 0.049 V/Fc–Fc , and the corresponding cathodic
a
peak potential value E (I) for signal I was ꢁ0.010 V/Fc–
pc
c
+
Fc ; a reversible electrochemical behaviour is presented.
3
. Electrochemistry
The DE was 0.059 V and independent of scan rate (0.1–
p
ꢁ
1
1
V s ), the cathodic peak current was proportional to
1
/2
The electrochemical behaviour of compounds 8 and 13b
v
, indicating that process I is a diffusion-controlled pro-
was investigated by cyclic voltammetry. In all experiments,
cess [13].

2878
T.K. Berestneva et al. / Journal of Organometallic Chemistry 691 (2006) 2872–2882
ΙΙ
1
1
1
4
2
0
8
6
4
2
0
2
4
6
8
a
Ι
a
E
+
λ
E
-
λ
-
-
-
-
ΙΙ
c
Ι
c
-
10
-0.8
-0.6
-0.4
-0.2
0.0
0.2
0.4
0.6
0.8
+
E(V/Fc-Fc )
ꢁ
3
ꢁ3
Fig. 3. Cyclic voltammograms for a solution 1.0 · 10 mol dm of compound 8 in the presence of 0.1 M TBABF
4
in acetonitrile. The scan potential was
ꢁ1
initiated from Eocp to positive direction. Scan rate 0.1 V s . The working electrode used was platinum.
The anodic and cathodic peak potential values for
attacks at the C-1 or C-2 positions of 4e, the initially
formed intermediates A and B (Scheme 7) usually from
products that retain the original tree-membered ring or
undergo CAC bond cleavage to give ring-opened products.
Note that obtained products (the main process) that retain
the methylthio-substituent dominate in the reaction prod-
ucts. This behavior of diferrocenyl(methylthio)cycloprope-
nylium 4e is substantially different to that of its ethoxy
analog 4a [9].
signals IIa and IIc E (II) and E (II) are 0.277 and
pa
pc
+
0
.215 V/Fc–Fc , respectively. The DE was also indepen-
p
dent of scan rate (0.1–1 V s ), and the cathodic peak current
was proportional to v . Process I and II are attributed for a
two consecutives one-electron transfer. A similar behaviour
was reported for diferrocenyl compounds [14–16].
ꢁ1
1
/2
The formal electrode potential was evaluated with the
half sum of the anodic and cathodic peak potentials,
0
0
E = (E + E ), for the electrochemical processes I and
pa
pc
0
0
+
II. The values obtained were E (I) = 0.019 V/Fc–Fc and
5. Experimental
0
0
0
0
+
E (II) = 0.246 V/Fc–Fc , DE (II–I) = 0.227 V. The value
of comproportionation constant Kcom evaluated according
to the literature for a EE mechanism [13–16] was 7038.
The electrochemical behaviour for compounds 13b is
very similar to that observed for 8, though there are slight
changes in the values of peak potentials. The formal elec-
All the solvents were dried according to the standard
procedures and were freshly distilled before use. IR spectra
of compound 8 was obtained for samples as KBr pellets on
a Specord IR-75 instrument. UV spectra of compound 8
was recorded on a Specord UV–Vis spectrophotometer.
The mass spectrum of compounds 8, 13a-c, 15 were
obtained on a Varian-MAT CH-6 instrument (EI, 70 eV).
0
0
trode potential of processes I and II, were E (I) =
0
+
0
+
0
.007 V/Fc–Fc and E (II) = 0.237 V/Fc–Fc . The values
0
0
1
13
of DE (II–I) and comproportionation constant K
were
The H and C NMR spectra were recorded on a Unity
Inova Varian spectrometer (300 and 75 MHz) for solutions
in CDCl and CD Cl with Me Si as the internal standard.
com
0
.230 V and 70912, respectively.
The similar values of DE (II–I) and Kcom for com-
0
3
2
2
4
pounds 8 and 13b can be attributed for the same stability
of the mixed valence state Fc–Fc in both compounds
Chemical shifts are given in ppm and J values in Hz. An
Elemental Analysis System GmbH was used for elemental
analyses. Columns chromatography was carried out on
alumina (Brockmann activity III).
+
[
17]. The values of Kcom suggests that the electronic charge
is slightly delocalized in the mixed valence compound gen-
erated electrochemically, according to the Robin-Day clas-
sification (class II) [16,17].
The unit cell parameters and the X-ray diffraction
intensities were recorded on a Bruker Smart Apex CCD
area detector/x diffractometer. The crystallographic data,
the experimental conditions, and corrections are given in
Table 1. The structures of compounds 8 and 13b were
solved by direct method (SHELXS) and refined using full-
4
. Conclusion
Thus, the results of this study support our previous con-
clusion [10] that, depending on whether the nucleophile
2
matrix least-squares on F .

T.K. Berestneva et al. / Journal of Organometallic Chemistry 691 (2006) 2872–2882
2879
Table 1
Crystal data and structure refinement parameters for compounds 8 and 13b
Data
8
13b
Molecular formula
Formula weight (g mol
Temperature (K)
Crystal system
C
470.18
293(2)
24
H
22Fe
2
OS
38 2 2
C H36Fe O S
ꢁ1
)
668.43
291(2)
Triclinic
Triclinic
ꢀ
ꢀ
Space group
P1
P1
˚
a (A)
7.6252(4)
10.5927(6)
11.1169(6)
14.0025(8)
85.042(1)
86.678(1)
68.941(1)
1532.4(2)
2
˚
b (A)
10.6547(6)
12.9373(7)
85.724(1)
74.659(1)
79.913(1)
997.52(9)
2
˚
c (A)
a (ꢁ)
b (ꢁ)
c (ꢁ)
˚
3
V (A )
Z
ꢁ3
D
calc (Mg mm
)
1.565
1.571
1.449
1.049
ꢁ1
Absorption coefficient (mm
)
F(000)
Radiation, k(Mo Ka) (A)
Monochromator
h range (ꢁ)
Reflections collected
Reflections independent
484
696
˚
0.71073
Graphite
1.94–25.01
13850
0.71073
Graphite
1.97–25.00
12710
7053
5411
R
int
0.0385
0.0314
Final R indices [I > 2r(I)]
R indices (all data)
Refinable parameters
Goodness-of-fit
Refinement method
Minimum/maximum residual electron density (e A
R
R
1
1
= 0.0465, wR
= 0.0725, wR
2
2
= 0.0718
= 0.0768
R
R
1
= 0.0318, wR
= 0.0424, wR
2
= 0.0641
= 0.0665
1
2
254
1.009
389
0.895
2
2
Full-matrix-least-squares on F
ꢁ0.366/0.716
Full-matrix-least-squares on F
ꢁ0.207/0.321
˚
ꢁ3
)
The following reagents were purchased from Aldrich:
ferrocene, 98%; aluminum chloride, 99.99%; tetrachlorocy-
clopropene, 98%; triethyloxonium tetrafluoroborate, 1.0 M
solution in dichloromethane; piperidine, 99%; potassium
tert-butoxide, 95%; sodium ethoxide, 96%; sodium methox-
ide, 95%; sodium benzyloxide, 1.0 M solution in benzyl
alcohol; p-cresol, 99%; iodomethane, 99.5%; sodium
benzene with equivalent amounts of n-bytyllithium. 2,3-
Diferrocenylcyclopropenone was obtained from the ferro-
cene and tetrachlorocyclopropene in the presence of AlCl3
according to the standard procedure [19,20]. Ethoxy(di-
ferrocenyl)cyclopropenylium tetrafluoroborate 4a was
obtained from the 2,3-diferrocenylcyclopropenone 7 in
the presence of triethyloxonium tetrafluoroborate (1.0 M
solution in dichloromethane) [8].
hydrosulfide hydrate NaHS Æ xH O.
2
All electrochemical measurements were performed in ace-
tonitrile (HPLC grade) solution containing 0.1 M tetra-N-
5.1. Diferrocenyl(piperidino)cyclopropenylium
tetrafluoroborate (4b)
butylammonium tetrafluoroborate (TBABF ) as supporting
4
electrolyte. A potentiostat/galvanostat EG&G PAR model
2
63 controlled by a PC software was used. A typical three-
Piperidine (4.0 ml) was added dropwise to a solution of
salt 4a (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 stir-
red for 30 min, concentrated in vacuo to 30 ml, and left
overnight at 20 ꢁC. 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 precipitate that
formed was filtered off, washed with dry ethanol, and dried
in a vacuum desiccator 4b that formed was filtered off,
washed with dry ethanol, and dried in a vacuum desiccator,
yield 77%, red-violet crystals, m.p. 204–205 ꢁC (lit. [8]: 204–
electrode array was employed for all electrochemical mea-
surements: platinum disk as working electrode, platinum
wire as counter-electrode, and a pseudo reference electrode
of silver wire immersed in an acetonitrile solution with
0
.1 M tetra-N-butylammonium chloride (TBACl). All solu-
tions were bubbled with nitrogen prior to each measurement.
All voltammograms were initiated from open circuit poten-
tial (Eocp) and the scan potential was obtained in both posi-
tive and negative directions. All potentials were reported
+
versus the couple Fc–Fc according to IUPAC convention
+
[
18]. The formal electrode potential for (Fc–Fc ) redox pair,
1
determined by voltamperometric studies, was 0.743 V versus
Ag|AgCl (MeCN).
205 ꢁC). H NMR: (CD Cl ): d 1.76 (2H, m, CH ), 2.75
2
2
2
(2H, m, CH ), 2.95–3.41 (4H, m, 2CH ), 3.64 (2H, m,
2
2
Lithium 1-ferrocenylethoxide and lithium 2-ferrocenyl-
isopropoxide were prepared by treating solutions of 1-fer-
rocenylethanol and 2-ferrocenylpropanol, respectively, in
CH ), 4. 26 (10H, s, 2C H ), 4.31 (2H, m, C H ), 4.49
2 5 5 5 4
(2H, m, C H ), 4.69 (2H, m, C H ), 4.87 (2H, m, C H ).
5
4
5
4
5
4
1
3
C NMR (CD Cl ): d 30.87, 43.58, 48.93 (5CH ), 60.31
2
2
2

2880
T.K. Berestneva et al. / Journal of Organometallic Chemistry 691 (2006) 2872–2882
(
(
2CipsoFc), 70.72 (2C H ), 71.68, 74.20 (2C H ), 130.19
m, C H ), 4.48 (2H, m, C H ), 4.68 (2H, m, C H ), 4.73
5 4 5 4 5 4
5
5
5
4
1
3
2C), 138.89 (C–N). Anal. Calc. for C H BF Fe N: C,
(2H, m, C H ), 7.05 (1H, s, CH@). C NMR (CDCl ): d
2
8
28
4
2
5
4
3
5
5
8.28; H, 4.89; F, 13.17; Fe, 19.36; N, 2.43. Found: C,
8.44; H, 4.68; F, 13.29, Fe 19.18; N, 2.59%. MS m/z
18.86 (CH ), 69.38, 70.10 (2C H ), 68.33, 68.80, 71.34,
3 5 5
71.84 (2C H ), 79. 25, 80.06 (2CipsoFc), 135.16 (CH@),
5
4
(
%): 577 (89), 491 (100).
135.59 (C), 197.57(C@O). Anal. Calc. for C H Fe OS:
2
4
22
2
C, 61.30; H, 4.72; Fe, 23.75; S, 6.83. Found: C, 59.88; H,
+
5
.2. 2,3-Diferrocenylcyclopropenethione (7a)
4.82; Fe, 22.47; S, 12.89%. MS: m/z 500 [M] . 0.063 g
(15%) of the diferrocenylcyclopropenone (7), m.p. 182–
A solution of NaHS Æ xH O (1.0 g) in water (10 ml) was
183 ꢁC (lit. [19]: m.p. 182–183 ꢁC) and 0.033 g (6%) of the
2
added to a stirred suspension of salts 4b (5 mmol) in etha-
nol (100 ml) at 20 ꢁC and stirred for 6 h. The precipitate
that formed was filtered off, washed with water, and dried
in air. The yield of the title compound was ꢀ2.0 g (91%),
dark red fine crystals, m.p. 208–209 ꢁC. Following purifica-
tion by chromatography on alumina (hexane–dichloro-
1,2-diferrocenyl-1,1,3-trimethylthio-2-propene (10), red-
1
brown powder, m.p. 193–194 ꢁC. H NMR (CDCl ): d
3
2.60 (6H, s, 2CH ), 2.77 (3H, s, CH ), 4.08 (5H, s,
3
3
C H ), 14.10 (5H, s, C H ), 4.03 (2H, m, C H ), 4.14
5
5
5
5
5
4
(2H, m, C H ), 4.28 (2H, m, C H ), 4.39 (2H, m, C H ),
5
4
5
4
5
4
6.31 (1H, s, CH@). Anal. Calc. for C H Fe S : C,
2
6
28
2 3
1
methane, 5:1), thione 7a had m.p. 209–210 ꢁC. H NMR
56.96; H, 5.15; Fe, 20.38; S, 17.51. Found: C, 57.09; H,
+
(
CDCl ): d 4.27 (10H, s, 2C H ), 4.69 (4H, m, C H ),
5.21; Fe, 20.42; S, 17.40%. MS: m/z 548 [M] .
3
5
5
5
4
1
3
4
7
1
4
.98 (4H, m, C H ). C NMR (CDCl ): d 63.25 (2CipsoFc),
5 4 3
0.14 (2C H ), 71.29, 72.95 (2C H ), 152.66 (2C),
5.5. Reactions of salt (4e) with potassium tert-butoxide
5
5
5
4
71.15(C@S). Anal. Calc. for C H Fe S: C, 63.05; H,
2
3
18
2
.14; Fe, 25.49. Found: C, 62.83; H, 4.19; Fe, 25.57%.
Salt 4e (0.58 g, 1.0 mmol) was refluxed in a mixture of
potassium tert-butoxide (0.34 g, 3.0 mmol) and benzene
+
MS: m/z 438 [M] .
(50 ml) for 3 h. The solvent was evaporated in vacuo and
5
.3. Diferrocenyl(methylthio)cyclopropenylium iodide (4e)
the residue was chromatographed on alumina (hexane–
diethyl ether, 4:1) to afford 0.39 g (82%) of the 3-methyl-
thio-1,2-diferrocenylpropenone (8), red crystals, m.p.
Methyl iodide (0.5 ml) was added dropwise to a solution
+
of cyclopropenethione 7a (0.88 g, 2.0 mmol) in dry benzene
50 ml) and the mixture was stirred in an inert dry atmo-
157–159 ꢁC. MS: m/z 470 [M] .
(
sphere for 3 h. The red-violet precipitate of the salt 4e
5.6. Reactions of salt (4e) with sodium ethoxide
was filtered off, washed with benzene, and dried in a vac-
uum-dessicator. The yield of the iodide 4e was 0.93 g
Salt 4e (0.58 g, 1.0 mmol) was refluxed in a mixture of
sodium ethoxide (0.2 g, 3.0 mmol) and benzene (50 ml)
for 3 h. The solvent was evaporated in vacuo and the resi-
due was chromatographed on alumina (hexane–diethyl
ether, 4:1) to afford 0.37 g (79%) of the 3-methylthio-1,2-
diferrocenylpropenone (8), red-brown crystals, m.p. 158–
1
(
80%), m.p. 248–250 ꢁC. H NMR (CD Cl ): d 3.25 (3H,
2
2
1
3
s, CH ), 4.49 (10H, s, 2C H ), 5.09 (8H, m, 2C H ).
C
3
5
5
5
4
NMR (CD Cl ): d 21.26 (CH ), 58.79 (2CipsoFc), 72.26
2
2
3
(
2C H ), 74.32, 77.50 (2C H ), 151.27 (2C), 152.30(C–S).
5 5 5 4
Anal. Calc. for C H Fe IS: C, 49.69; H, 3.65; Fe, 19.24;
2
4
21
2
+
I, 21.88%. Found: C, 49.48; H, 3.71; Fe, 19.17; I 21.97%.
159 ꢁC. MS: m/z 470 [M] .
5
.4. Reactions of salt (4e) with water
5.7. Reactions of salt (4e) with lithium ferrocenylethoxide
Salt 4e (0.58 g, 1.0 mmol) was refluxed in a mixture of
This was carried out analogously using salt 4e (1.16 g,
2.0 mmol), lithium ferrocenylethoxide (0.6 g, 2.5 mmol)
and benzene (50 ml). The reaction mixture was worked
up as described above, subsequent chromatography on
Al O (hexane–diethyl ether, 6:1) gave vinylferrocene
water (0.5 ml) and benzene (50 ml) for 2 h. The solvent
was evaporated in vacuo and the residue was chromato-
graphed on alumina (hexane–diethyl ether, 4:1) to afford
0
.025 g (5%) of the 2,3-diferrocenyl-1,1-dimethylthiocyclo-
2
3
propene (9), orange crystals, m.p. 136–137 ꢁC. MS: m/z 500
(11c), yield 0.29 g (72%), and 3-methylthio-1,2-diferroce-
nylpropenone (8), yield 0.75 g (80%).
+
[
M] . Anal. Calc. for C H Fe S : C, 60.03; H, 4.84; Fe,
25 24 2 2
2
1
2.33; S, 12.80. Found: C, 59.88; H, 4.82; Fe, 22.47; S,
Compound 11c, yield 0.29 g (72%), orange crystals, m.p.
+
2.89%. dH (300 MHz, CDCl ): 2.31 (6H, s, 2CH ), 4.29
62 ꢁC (lit. [14]: 62 ꢁC). MS: m/z 212 [M] .
3
3
(
10H, s, 2C H ), 4.43 (4H, m, C H ), 4.55 (4H, m,
Compound 8, yield 0.75 g (80%), red-brown powder,
5
5
5
4
+
C H ); 0.29 g (61%) of the 3-methylthio-1,2-diferrocenyl-
m.p. 158–159 ꢁC. MS: m/z 470 [M] .
5
4
propenone (8), red-brown crystals, mp 157–159 ꢁC. m
max
ꢁ1
(
KBr)/cm : 473, 486, 522, 742, 756, 822, 846, 1002,
5.8. Reactions of salt (4e) with lithium
ferrocenylisopropoxide
1
1
2
027, 1043, 1104, 1219, 1270, 1371, 1442, 1565, 1638,
720, 1859, 2925, 3026, 3079; kmax (CHCl , 20ꢁ)/nm: 207,
51, 298, 449, 455. H NMR (CDCl ): d 2.50 (3H, s,
3
1
Analogous treatment of salt 4e (1.16 g, 2.0 mmol) in dry
3
CH ), 4.18 (5H, s, C H ), 4.19 (5H, s, C H ), 4.27 (2H,
benzene (50 ml) with lithium ferrocenylisopropoxide
3
5
5
5
5

T.K. Berestneva et al. / Journal of Organometallic Chemistry 691 (2006) 2872–2882
2881
(
0
(
0.75 g, 3 mmol) afforded isopropenylferrocene 11d, yield
.34 g (75%), and 3-methylthio-1,2-diferrocenylpropenone
8), yield 0.79 g (83%).
was separated, washed with water (2 · 20 ml) and solvent
was evaporated in vacuo. The residue was chromato-
graphed on Al O (hexane–diethyl ether, 2:1) to give 1,1-
2
3
Compound 11d, yield 0.34 g (75%), orange crystals, m.p.
bis-p-tolyloxy-3-methylthio-1,2-diferrocenylpropene (13c),
1
6
(
4–65 ꢁC (lit. [14]: 64–66 ꢁC). H NMR (CDCl ): d 2.05
yield 0.45 g (67%), as a orange powder, m.p. 183–184 ꢁC.
3
1
3H, bs, CH ), 4.18 (5H, s, C H ), 4.21 (2H, m, C H ),
H NMR (CDCl ): d 2.24 (6H, s, 2CH ), 2.33 (3H, s,
3
5
5
5
4
3
3
4
.38 (2H, m, C H ), 4.82 (1H, bs, CH @), 5.12 (1H, bs,
CH ), 4.09 (5H, s, C H ), 4.30 (5H, s, C H ), 4.19 (1H,
m, C H ), 4.42 (1H, m, C H ), 4.47 (1H, m, C H ), 4.50
5 4 5 4 5 4
5
4
2
3 5 5 5 5
+
CH @). MS: m/z 226 [M] .
2
Compound 8, yield 0.79 g (83%), red-brown crystals,
m.p. 157–159 ꢁC. MS: m/z 470 [M] .
(1H, m, C H ), 4.63 (2H, m, C H ), 5.01 (2H, m, C H ),
5 4 5 4 5 4
7.86 (1H, s, CH@), 6.79–7.17 (8H, m, 2Ar). Anal. Calc.
+
for C H Fe O S: C, 68.28; H, 5.43; Fe 16.71. Found:
3
8
36
2
2
+
5
(
.9. 1,1-Dimethoxy-3-methylthio-1,2-diferrocenylpropene
13a)
C, 68.09; H, 5.51; Fe, 16.67%. MS: m/z 668 [M] .
5.12. Reactions of salt (4e) with 2-methyl-2-propanol,
ethanol, 1-ferrocenylethanol, 2-ferrocenyl-2-propanol
Salt 4e (0.58 g, 1.0 mmol) was refluxed in a mixture of
sodium methoxide (0.22 g, 4.0 mmol), 2 ml methanol and
benzene (50 ml) for 2 h. The solvent was evaporated in
vacuo and the residue was chromatographed on alumina
Salt 4e (0.58 g, 1.0 mmol) was refluxed in a mixture of 2-
methyl-2-propanol (3.0 ml), triethylamine (5.0 ml) and ben-
zene (50 ml) for 3 h. The solvent was evaporated in vacuo
and the residue was chromatographed on alumina (hex-
ane–diethyl ether, 4:1) to afford 0.38 g (81%) of the 3-meth-
ylthio-1,2-diferrocenylpropenone 8, red crystals, m.p. 157–
(
0
(
hexane–diethyl ether, 5:1) to give compound 13a, yield
1
.42 g (80%), orange powder, m.p. 164–165 ꢁC. H NMR
CDCl ): d .47 (3H, s, CH ), 3.25 (6H, s, 2CH ), 4.08
3
3
3
(
5H, s, C H ), 4.21 (5H, s, C H ), 4.07 (2H, m, C H ),
5 5 5 5 5 4
+
4
.19 (2H, m, C H ), 4.23 (2H, m, C H ), 4.73 (2H, m,
159 ꢁC. MS: m/z 470 [M] .
5
4
5
4
1
3
C H ), 6.75 (1H, s, CH@). C NMR (CDCl ): d 19.20
Analogous treatment of salt 4e (1.0 mmol) in dry benzene
(50 ml) with ethanol, 1-ferrocenylethanol or 2-ferrocenyl-2-
propanol afforded 3-methylthio-1,2-diferrocenylpropenone
(8), yield 76–83% and olefins 11c and 11d.
5
4
3
(
SCH ), 49.76 (2OCH ), 69.08, 69.26 (2C H ), 66.80,
3 3 5 5
6
7.36, 68.37, 69.61 (2C H ), 82.11, 91.61 (2CipsoFc),
5 4
1
28.99 (CH@), 103.74, 131.33 (2C). Anal. Calc. for
C H Fe O S: C, 60.49; H, 5.47; Fe 21.64. Found: C,
Analogous treatment of salt 4e (1.0 mmol) in dry ben-
zene (50 ml) with methanol, benzyl alcohol or p-cresol
afforded ketals 13a–c, yield 66–72%.
2
6
28
2
2
+
6
0.64; H, 5.38; Fe, 21.47%. MS: m/z 516 [M] .
5
(
.10. 1,1-Dibenzyloxy-3-methylthio-1,2-diferrocenylpropene
13b)
5.13. 3,4-Diferrocenylpyrazole (15)
This was carried out analogously using salt 4e (0.58 g,
.0 mmol), sodium benzyloxide (1.0 M solution in benzyl
This was obtained according to the known procedure
[21] by reactions of the compounds 8 and 13a–c, respec-
tively, with hydrazine hydrate in ethanol. The reaction
product that precipitated was collected by filtration,
washed with ethanol and dried in vacuo. The yield ranged
1
alcohol, 7.0 ml) and benzene (50 ml). The reaction mixture
was worked up as described above, subsequent chromatog-
raphy on Al O (hexane–diethyl ether, 3:1) gave compound
2
3
1
1
1
(
3b, yield 0.48 g (71%), as a orange crystals, m.p. 174–
from 62% to 71%, m.p. 238–239 ꢁC, orange powder. H
1
76 ꢁC. H NMR (CDCl ): d 2.33 (3H, s, CH ), 4.12
NMR (CDCl ): d 4.09 (5H, s, C H ), 4.14 (5H, s,
3
3
3
5
5
5H, s, C H ), 4.18 (5H, s, C H ), 4.10 (2H, m, C H ),
C H ), 4.21 (2H, m, C H ), 4.31 (2H, m, C H ), 4.39
5 5 5 4 5 4
5
5
5
5
5
4
4
.19 (2H, m, C H ), 4.35 (2H, m, C H ), 4.82 (2H, m,
(2H, m, C H ), 4.53 (2H, m, C H ), 6.40 (1H, bs, NH),
5 4 5 4
5
4
5
4
1
3
C H ), 4.67 (4H, bs, 2CH ), 6.86 (1H, s, CH@), 7.25–
7.69 (1H, s, CH@). C NMR (CDCl ): d 69.20, 69.30
5
4
2
3
1
3
7
6
6
1
.42 (10H, m, 2Ph). C NMR (CDCl ): d 19.14 (SCH ),
(2C H ), 67.68, 68.27, 68.49, 68.59 (2C H ), 78.74, 78.40
3
3
5
5
5
4
3.95 (2CH ), 69.17, 69.28 (2C H ), 66.99, 67.49, 68.39,
(2CipsoFc), 116.52 (CH@), 139.20, 140.34 (2C). Anal.
2
5
5
9.77 (2C H ), 82.10, 91.70 (2CipsoFc), 129.04 (CH@),
Calc. for C H Fe N : C, 63.34; H, 4.62; Fe, 25.62; N,
5
4
23 20
2
2
04.23, 131.34 (2C), 126.91, 127.08, 128.33 (2Ph), 138.91
6.42. Found: C, 68.29; H, 4.70; Fe, 25.78; N, 6.31%.
+
(
2Cipso). Anal. Calc. for C H Fe O S: C, 68.28; H, 5.43;
MS: m/z 436 [M] .
38
36
2
2
Fe, 16.71. Found: C, 68.41; H, 5.32; Fe, 16.88%. MS:
+
m/z 668 [M] .
6. Supplementary material
5
.11. Reactions of salt (4e) with sodium p-tolyloxide
Crystallographic data for the structural analysis have
been deposited with the Cambridge Crystallographic Data
Centre, CCDC No. 292194 for compound 8 and CCDC
No. 235195 for compound 13b. Copies of this information
may be obtained free of charge from The Director, CCDC,
12 Union Road, Cambridge CB2 IEZ, UK (fax: +44 1223
A solution 0.33 g (3 mmol) p-cresol, 0.17 g (2.5 mmol)
EtONa in benzene (70 ml) was added 0.58 g (1.0 mmol)
of compound 4e. The mixture was refluxed for 3 h and
quenched by addition of water (100 ml). The organic layer

2882
T.K. Berestneva et al. / Journal of Organometallic Chemistry 691 (2006) 2872–2882
3
36 033; e-mail: deposit@ccdc.cam.ac.uk or www: http://
[8] E.I. Klimova, T. Klimova Berestneva, S. Hernandez Ortega, D.
´
M e´ ndez Iturbide, A. Garc ´ı a Marquez, M. Mart ´ı nez Garc ´ı a, J.
Organomet. Chem. 690 (2005) 3333.
www.ccdc.cam.ac.uk).
[
9] E. Klimova, T. Klimova, S. Betanzos Lara, J. Dominguez Chavez, S.
Hernandez Ortega, A. Toscano, M. Mart ´ı nez Garc ´ı a, J. Organomet.
Chem. 691 (2006) 1.
Acknowledgements
This work was supported by the DGAPA – UNAM
Mexico, Grant IN 207606). Thanks are due to J.M. Mart ´ı -
nez Mendoza, E.A. V a´ zquez L o´ pez, A. Acosta Huerta,
G.A. Duarte Lisci, M. Guti e´ rrez Franco and R.I. Del
Villar Morales for their technical assistance.
[10] T. Klimova Berestneva, E.I. Klimova, A.R. Toscano, C. Alvarez
Toledano, S. Hern a´ ndez Ortega, M. Mart ´ı nez Garc ´ı a, Eur. J. Org.
Chem. (2005) 4406.
(
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