Synthetic and electrochemical studies on 1,1′-dithia-substituted derivatives of ferrocene and structure of 1,3-dithia[3]ferrocenophane [Fe(C5H4S)2CH2]

Article abstract of DOI:10.1021/om020041z

The bimetallic complexes fc(μ₂-S)₂TiCp₂2 (1, fc = 1,1′-ferrpcenyl, Cp = cyclopentadienyl) and fc(μ₂-S₂)(μ₂-S)TiCp₂ (2) were synthesized by reaction of fc(SH)₂ with Cp₂TiCl₂, and from fcS₃ and Cp₂Ti(CO)₂, respectively. The novel tetrasulfane fcS₄ was obtained from 2 and SCl₂. 1,3-Dithia[3]ferrocenophane fcS₂CH₂ was obtained from fc(SH)₂ and CH₂Cl₂ in the presence of Cp₂TiCl₂ and KOH. The molecular and crystal structure of fcS₂CH₂ was determined by X-ray crystallography; the molecular symmetry is C_s. Electrochemical studies on the recently prepared ferrocenophanes fcS₂-1-SO, fcS₂-1-SO₂, and fcS₂-2-SO show that, with respect to fcS₃, the progressive oxidation of the trisulfane bridge makes more and more difficult the fc/fc⁺ oxidation, whereas insertion of a Cp₂Ti fragment exerts the opposite effect.

Full text of DOI:10.1021/om020041z

2604
Organometallics 2002, 21, 2604-2608
Articles
Syn th etic a n d Electr och em ica l Stu d ies on
1,1′-Dith ia -Su bstitu ted Der iva tives of F er r ocen e a n d
Str u ctu r e of 1,3-Dith ia [3]fer r ocen op h a n e
[F e(C5H4S)2CH2]
Ralf Steudel,* Karin Hassenberg, and J oachim Pickardt
Institut fu¨r Chemie, Technische Universita¨t Berlin, D-10623 Berlin, Germany
Emanuela Grigiotti and Piero Zanello*
Dipartimento di Chimica dell’Universita` di Siena, Via Aldo Moro, 53100 Siena, Italy
Received J anuary 17, 2002
The bimetallic complexes fc(µ2-S)2TiCp2 (1, fc ) 1,1′-ferrocenyl, Cp ) cyclopentadienyl)
and fc(µ2-S2)(µ2-S)TiCp2 (2) were synthesized by reaction of fc(SH)2 with Cp2TiCl2, and from
fcS3 and Cp2Ti(CO)2, respectively. The novel tetrasulfane fcS4 was obtained from 2 and SCl2.
1,3-Dithia[3]ferrocenophane fcS2CH2 was obtained from fc(SH)2 and CH2Cl2 in the presence
of Cp2TiCl2 and KOH. The molecular and crystal structure of fcS2CH2 was determined by
X-ray crystallography; the molecular symmetry is Cs. Electrochemical studies on the recently
prepared ferrocenophanes fcS2-1-SO, fcS2-1-SO2, and fcS2-2-SO show that, with respect to
fcS3, the progressive oxidation of the trisulfane bridge makes more and more difficult the
fc/fc+ oxidation, whereas insertion of a Cp2Ti fragment exerts the opposite effect.
1,2,3-Trithia[3]ferrocenophane fcS3 has been known
synthesized the bimetallic ferrocenophanes fcS2TiCp2 (1)
and fcS3TiCp2 (2) as potential precursors (Cp ) η5-C5H5)
which should react with sulfur chlorides and organic
sulfenyl chlorides to provide the corresponding novel
ferrocene derivatives. In fact, the formerly unknown
tetrasulfane fcS4 was obtained from 2. We also found a
novel synthetic access to fcS2CH2, the molecular struc-
ture of which is reported for the first time. In addition,
we report on the electronic effects caused by the replace-
ment of the bridging S3 chain for the sulfane oxide units
S-S(dO)-S, S-S-S(dO), and S-S-S(dO)2, respec-
tively, as derived from electrochemical studies.
Syn th eses. It was our aim to develop a synthetic ac-
cess to the hitherto unknown 1,1′-ferrocene polysulfanes
fcSn with n > 3. Since sulfur-rich organic polysulfanes
are best prepared from suitable titanocene precursors
by reaction with sulfur chlorides,6 we tried the same
route for the wanted ferrocene derivatives. The first step
is the preparation of a suitable bimetallic double-
sandwich complex like fc(µ2-S)2TiCp2 (1) and fc(µ2-S2)-
(µ2-S)TiCp2 (2) according to eqs 1 and 2, respectively.
for a long time from chemical,1 structural,2 and elec-
trochemical studies.3 Recently, the peroxo acid oxidation
of fcS3 afforded both the trisulfane-1-oxide fcS2-1-SO and
the corresponding sulfone fcS2-1-SO2, depending on the
stoichiometry of the reactants.4 The isomeric trisulfane-
2-oxide fcS2-2-SO was obtained from the dithiol fc(SH)2
and thionyl chloride.5 In an attempt to obtain access to
more sulfur-rich derivatives fcSn with n > 3 we have
* Corresponding authors. E-mail: steudel@schwefel.chem.tu-ber-
lin.de and zanello@unisi.it.
(1) See, for example: (a) Brandt, P. F.; Rauchfuss, T. B. J . Am.
Chem. Soc. 1992, 114, 1926. (b) Galloway, C. P.; Rauchfuss, T. B.
Angew. Chem. 1993, 105, 1407; Angew. Chem., Int. Ed. Engl. 1993,
32, 1319. (c) J ohnston, E. R.; Brandt, P. F. Organometallics 1998, 17,
1460. (d) Brandt, P. F.; Compton, D. L.; Rauchfuss, T. B. Organome-
tallics 1998, 17, 2702.
(2) Davis, B. R.; Bernal, I. J . Cryst. Mol. Struct. 1972, 2, 107.
(3) (a) Sato, M.; Tanaka, S.; Ebine, S.; Morinaga, K.; Akabori, S. J .
Organomet. Chem. 1985, 282, 247. (b) Beer, P. D.; Charlsley, S. M.;
J ones, C. J .; McCleverty, J . A. J . Organomet. Chem. 1986, 307, C19.
(c) Sidebotham, R. P.; Beer, P. D.; Hamor, T. A.; J ones, C. J .;
McCleverty, J . A. J . Organomet. Chem. 1989, 371, C31. (d) Osborne,
A. G.; Hollands, R. E.; Nagy, A. G. J . Organomet. Chem. 1989, 373,
229. (e) Ushijima, H.; Akiyama, T.; Kajitani, M.; Shimizu, K.; Aoyama,
M.; Masuda, S.; Harada, Y.; Sugimori, A. Bull. Chem. Soc. J pn. 1990,
63, 1015. (f) Zanello, P.; Opromolla, G.; Casarin, M.; Herberhold, M.;
Leitner, P. J . Organomet. Chem. 1993, 443, 199. (g) Galloway, C. P.;
Rauchfuss, T. B. Angew. Chem. 1993, 105, 1407; Angew. Chem., Int.
Ed. Engl. 1993, 32, 1319. (h) Long, N. J .; Raithby, P. R.; Zanello, P. J .
Chem. Soc., Dalton Trans. 1995, 1245.
Complexes 1 and 2 should then react with certain
sulfur chlorides according to eq 3 to produce the corre-
(5) Steudel, R.; Hassenberg, K.; Pickardt, J . Organometallics 1999,
18, 2910.
(4) Hassenberg, K.; Pickardt, J .; Steudel, R. Organometallics 2000,
19, 5244.
(6) Steudel, R.; Kustos, M. In Encyclopedia of Inorganic Chemistry;
King, R. B., Ed.; Wiley: Chichester, 1994; Vol. 7, pp 4009-4038.
10.1021/om020041z CCC: $22.00 © 2002 American Chemical Society
Publication on Web 05/24/2002

1,1′-Dithia-Substituted Derivatives of Ferrocene
Organometallics, Vol. 21, No. 13, 2002 2605
tetrathia[4]ferrocenophane fcS4 in 27% yield (after
chromatographic purification) as a yellow solid, eq 5.
Both in solution and in the solid state fcS4 slowly
decomposes at room temperature to fcS3 and S8. The
decomposition in the solid state can be slowed by
cooling, but even at -55 °C some decomposition oc-
curred.
When we tried to synthesize 1 from fc(SH)2 and Cp2-
TiCl2 in dichloromethane in the presence of KOH, we
surprisingly obtained fcS2CH2 instead (yield 35%), eq
6.
sponding ferrocene polysulfanes:
fcSxTiCp2 + SnCl2 f fcSx+n + Cp2TiCl2
(3)
The reaction according to eq 1 was carried out in
toluene using the dithiol fc(SH)2 prepared by reduction
of fcS3 with LiAlH4.7 Addition of NEt3 to the red solution
of fc(SH)2 and Cp2TiCl2 resulted in a color change to
dark green. After filtration the solvent was evaporated,
leaving the crude product 1 as a black-green powder
(yield 95%). This product produced a peak of relative
intensity 35 for the molecular ion in the EI mass
spectrum (base peak 100: Cp2TiS+). On reversed-phase
HPLC analysis, one major and two much smaller peaks
were observed. However, attempts to further purify the
crude product on a preparative scale by conventional
chromatographic separation resulted in decomposition.
Nevertheless, the spectroscopic data support the for-
mula, and the connectivity was established by reaction
with SOCl2, which produced the known trisulfane-2-
oxide fcS3O, as identified by IR, MS, and HPLC analysis
and comparison to an authentic sample,4 eq 4.
For this reaction to occur, the presence of Cp2TiCl2 is
not mandatory but the reaction is much slower without
Cp2TiCl2, which evidently functions as a catalyst. 1,3-
Dithia[3]ferrocenophane fcS2CH2 had previously been
synthesized from fc(SH)2 and CH2I29 and characterized
spectroscopically. The product was described as orange
crystals9,10 Our crude product from reaction 6, precipi-
tated at -55 °C, was dark green, obviously owing to
some admixed fcS2TiCp2 1, which is a likely byproduct.
Recrystallization of the crude product from CS2 pro-
duced yellow crystals. When the synthesis was carried
out in the absence of Cp2TiCl2, the yield was much lower
and the crude product was orange-yellow. The melting
temperature (182 °C) agrees with the literature values,
1
as does the H NMR spectrum.9,10 Even at the melting
temperature no decomposition was observed. Since the
crystal structure of fcS2CH2 had remained unknown, we
performed an X-ray diffraction analysis on single crys-
tals.
X-r a y Str u ctu r a l An a lysis of fcS2CH2. Orthorhom-
bic crystals of fcS2CH2 were obtained by partial evapo-
ration of a solution in CS2 at 4 °C. The molecular
structure is depicted in Figure 1. The molecular sym-
metry is Cs. The two cyclopentadienyl rings are eclipsed
and almost parallel (interplanar angle 4.59°, closing
toward the bridge). The molecular parameters all seem
to have normal values.
Electr och em istr y. Figure 2 compares the cyclic
voltammetric response given by the precursor fcS3 with
those of trisulfane-1-oxide, fc[3]S2-1-SO, and trisulfane-
1,1-dioxide, fc[3]S2-1-SO2, in dichloromethane solution.
Because of the instability of 1, we prepared complex
2 by the reaction shown in eq 2, which is in analogy
with the many known insertion reactions of the ti-
tanocene unit into S-S bonds, using the dicarbonyl.8
The brown solid of 2 (57% yield) was characterized by
1H NMR, UV-vis, and MS spectroscopy. Reaction of 2
with 1 equiv of SCl2 in carbon disulfide afforded 1,2,3,4-
(7) Bishop, J . J .; Davison, A.; Katcher, M. L.; Lichtenberg, D. W.;
Merrill, R. E.; Smart, J . C. J . Organomet. Chem. 1971, 27, 241.
(8) See, for example: (a) Bergemann, K.; Kustos, M.; Kru¨ger, P.;
Steudel, R. Angew. Chem. 1995, 107, 1481; Angew. Chem., Int. Ed.
Engl. 1995, 34, 1330. (b) Steudel, R.; Kustos, M.; Mu¨nchow, V.;
Westphal, U. Chem. Ber./ Recl. 1997, 130, 757. (c) Steudel, R.;
Schumann, O.; Buschmann, J .; Luger, P. Angew. Chem. 1998, 110,
515; Angew. Chem., Int. Ed. 1998, 37, 492.
(9) Davison, A.; Smart, J . C. J . Organomet. Chem. 1979, 174, 321.
(10) Abel, E. W.; Booth, M.; Brown, C. A.; Orrell, K. G.; Woodford,
R. L. J . Organomet. Chem. 1981, 214, 93.

2606 Organometallics, Vol. 21, No. 13, 2002
Steudel et al.
Ta ble 1. F or m a l Electr od e P oten tia ls (V, vs SCE),
P ea k -to-P ea k Sep a r a tion s (m V), a n d Ma xim u m
Wa velen gth (n m ) for th e F er r ocen e-Cen ter ed
Red ox P r ocesses Exh ibited by th e P r esen t
F er r ocen op h a n es
a
a,b
c
complex
fcS3
E°′(0/+) ∆Ep
Ep
λmax solvent reference
+0.67
+0.69
+0.86
+0.82
+1.05
85
375 CH2Cl2 3h
MeCN 3e
fcS2-1-SO
fcS2-2-SO
fcS2-1-SO2
fcS2-2-CH2
72 -1.31
78 -1.42
72 -1.46
630 CH2Cl2 this work
665 CH2Cl2 this work
620 CH2Cl2 this work
690 CH2Cl2 this work
MeCN 3e
F igu r e 1. Molecular structure of fcS2CH2 in the crystal.
Selected internuclear distances (Å) and angles (deg): S(1)-
C(11) ) 1.817(3), S(2)-C(11) ) 1.812(2), S(1)-C(10) )
1.755(2), S(2)-C(2) ) 1.756(2), C(11)-H(1a) ) 0.970,
C(10)-S(1)-C(11) ) 101.7(1), S(1)-C(11)-S(2) ) 115.8-
(1), C(11)-S(2)-C(2) ) 102.25, S(1)-C(11)-H(11a) )
108.3, C(10)-S(1)-C(11)-S(2) ) -74.8(1).
+0.66 100
+0.60
fc(CH2)2-2-S
fc(CH2)3
fc(CH2)2-1-CO +0.62
fcS3TiCp2
fcH
+0.41
+0.33
MeCN 3e
MeCN 11
MeCN 11
+0.20
+0.39
+0.38
78 -1.31d
78
64
CH2Cl2 this work
620 CH2Cl2 this work
620 MeCN this work
a
Measured at 0.2 V s-1
.
bPeak-potential value for irreversible
c
processes. Absorbance of the electrogenerated ferrocenium con-
geners. dFormal electrode potential measured at 2.0 V s-1
.
process more and more difficult.3e It is however also
evident that a similar inductive effect takes place upon
progressive oxygenation of the bridging sulfur atoms
according to the sequence fc[3]S3/fc[3]S2-1-SO (or, fc[3]-
S2-2-SO)/fc[3]S2-1-SO2. Such a remarkable electron-
withdrawing effect played by the oxygen atoms on the
other hand agrees well with the results obtained upon
substitution of one methylene group for a carbonyl group
in 1,2,3-trimethylene[3]ferrocenophane.11
It is also interesting to note that in the series
fc[3](CH2)3-nSn a linear trend exists as far as the
oxidation potentials and number of sulfur atoms are
concerned (correlation coefficient 0.99). Under the as-
sumption that the same additive electronic effects hold
in the series fc[4](CH2)4-nSn, from the known oxidation
potentials of the two members fc[4](CH2)4 (+0.30 V, in
MeCN)11,12 and fc[4](CH2)2(1,4-S)2 (+0.61 V, in MeCN)3a
an oxidation potential of 0.92 V (in MeCN) can be
predicted for the labile fc[4]S4.
It deserves attention that exhaustive one-electron
oxidation of fcS3 does not induce color changes with
respect to the original yellow solution, whereas the
electrogenerated monocations [fc[3]S2-1-SO]+, [fc[3]S2-
2-SO]+, and [fc[3]S2-1-SO2]+ assume a pale green color.
Taking into account that iron-centered ferrocenium
species are green to blue colored (λmax ≈ 620 nm), it can
be speculated that while the trisulfur bridge highly
contributes to the HOMO level of fcS3, thus to prevail
over the iron contribution, oxygen functionalization
seems to restore the iron-centered character of the
HOMO levels. In fact, the oxygenated monocations
display a flat band in the region from 620 to 670 nm,
assignable to their partial iron-centered character.
Finally, Figure 3 shows the cyclic voltammetric
behavior of fcS3-2-TiCp2.
F igu r e 2. Cyclic voltammograms recorded at a platinum
electrode on CH2Cl2 solutions containing [NBu4][PF6] (0.2
mol dm-3) and (a) fcS3 (1.1 × 10-3 mol dm-3); (b) fcS2-1-
SO (1.3 × 10-3 mol dm-3); and (c) fcS2-1-SO2 (1.2 × 10-3
mol dm-3). Scan rate 0.2 V s-1
.
As expected, all investigated complexes exhibit the
reversible ferrocene/ferrocenium oxidation. In fact, con-
trolled potential coulometry in correspondence to the
respective anodic processes consume one electron per
molecule. In each case the resulting solutions exhibit
voltammetric profiles quite complementary to the origi-
nal ones, thus testifying to the chemical reversibility of
the respective one-electron removals.
Analysis of the cyclic voltammetric responses with a
scan rate varying from 0.02 to 1.00 V s-1 shows that
the current ratio ipc/ipa is constantly equal to 1 (in
agreement with controlled potential coulometric re-
sults), the current function ipav-1/2 stays constant, and
the peak-to-peak separation ∆Ep is around 70-80 mV
at low scan rates (from 0.02 to 0.1 V s-1) and slightly
increases to 90-100 mV at higher scan rates. Taking
into account that under the same experimental condi-
tions unsubstituted ferrocene displays a similar volta-
mmetric trend, we assume that the oxidation process
of the present ferrocenophanes is substantially revers-
ible from the electrochemical viewpoint, which implies
that no significant geometrical reorganization would
follow the electron removal processes.
As can be seen from the voltammetric profile in Figure
3a, the presence of the TiCp2 fragment in the bridge
significantly affects the redox pattern with respect to
those discussed above. Let us first discuss the anodic
part. A first anodic process, with features of chemical
In Table 1 the formal electrode potentials of the
mentioned processes are compiled. These data confirm
the previous finding that in the sequence fc[3](CH2)3/
fc[3]S2-2-CH2/fc[3]S3 the progressive substitution of
methylene groups for sulfur atoms makes the oxidation
(11) Toma, Sˇ.; Solcˇa´niova´, E.; Nagy, A. G. J . Organomet. Chem.
1985, 288, 331.
(12) Fujita, E.; Gordon, B.; Hilmann, M.; Nagy, A. G. J . Organomet.
Chem. 1981, 218, 105.

1,1′-Dithia-Substituted Derivatives of Ferrocene
Organometallics, Vol. 21, No. 13, 2002 2607
preparation of many novel ferrocene derivatives by
reaction with suitable sulfur-chlorine compounds, as has
been shown for other titanocene dithiolato complexes.6,15
Exp er im en ta l Section
Gen er a l Con sid er a tion s. All syntheses were performed
under an atmosphere of nitrogen. Solvents were dried and
1
distilled prior to use. H and 13C NMR spectra were recorded
at room temperature on Bruker ARX200 and ARX400 instru-
ments. Mass spectra were measured with an AMS Intectra
instrument, based on Varian MAT 311A equipment. UV-vis
spectra were obtained with a Waters 990 diode-array detector
(190-800 nm) connected on-line to the HPLC equipment.
Elemental analyses were performed on a Perkin-Elmer 2700
CHNS analyzer. Materials and apparatus for electrochemistry
have been described elsewhere.16 All potential values refer to
the saturated calomel electrode (SCE).
P r ep a r a tion of [fc(µ2-S)2TiCp 2] (1). To a solution of Cp2-
TiCl2 (309 mg, 1.24 mmol) in 80 mL of toluene are added 331
mg of fc(SH)2 (1.24 mmol) and 250 mg of Et3N (2.48 mmol).
After stirring for 4 h at room temperature the dark green
solution is filtered and the solvent evaporated in a vacuum,
resulting in a black-green residue of crude 1 (497 mg). 1H NMR
(C6D6): δ 3.94 (dt, 2H), 4.08 (m, 2H), 4.14 (dt, 2H), 4.25 (m,
2H), 5.80 (s, 10H). UV-vis (methanol): 215, 240, 303, 432,
640 nm. MS (249 °C, m/z): 426 (35, M+), 361 (40, M - Cp+),
248 (30, fcS2+), 209 (100, Cp2TiS - H+), 186 (44, Cp2Fe+), 178
(31, Cp2Ti+).
F igu r e 3. Cyclic voltammograms recorded at a platinum
electrode on a CH2Cl2 solution of fcS3-2-TiCp2 (1.3 × 10-3
mol dm-3). [NBu4][PF6] (0.2 mol dm-3) supporting electro-
lyte. (a,b) Original response; (b) after exhaustive oxidation
at the first anodic step. Scan rate 0.2 V s-1
.
reversibility, is followed by a second irreversible oxida-
tion (Ep ) +1.08 V). In addition, a minor peaks system
(starred) appears after traversing the first, ferrocene-
centered oxidation. Such a profile predicts that the
starred peaks system may be due to a new species
arising from slow chemical complications following the
ferrocene-centered oxidation (in fact, the current ratio
ipc/ipa of the first anodic process is equal to 0.7 at 0.02
V s-1 and then tends to increase with the scan rate,
reaching the unity value at 1.0 V s-1). As a matter of
fact, exhaustive oxidation in correspondence to the first
anodic process (Ew ) +0.5 V) makes the brown color of
the original solution turn yellow, affording concomi-
tantly a new species, which gives rise to a reversible
peaks system (E°′ ) +0.7 V) just coincident with the
above-mentioned starred peaks system in Figure 3b. We
did not succeed in identifying such a new product by
mass spectrometry. In view of the highest oxidation
state of Ti in the TiCp2 fragment, the irreversible
oxidation at high potential values is attributed to a
sulfur-centered electron removal.
As far as the cathodic path is concerned, in agreement
with previous assignments on ferrocene-titanium de-
rivatives,13 the partially chemically reversible reduction
is easily assigned to the Ti(IV)/Ti(III) reduction of the
bridging Ti(IV) fragment. In this case the electron
addition is also complicated by fast degradation reac-
tions. In fact, the relative current ratio, ipa/ipc, is 0.2 at
0.2 V s-1 and tends to increase with the scan rate,
reaching the value of 0.4 at 2.0 V s-1. It is interesting
to note the strong electron-donating effect played by the
TiCp2 fragment, which makes the oxidation of fcS3-2-
TiCp2 easier by about 0.4 V with respect to fcS3.
P r ep a r a tion of [fc(µ2-S)(µ2-S2)TiCp 2] (2). To a solution
of fcS3 (239 mg, 0.854 mmol) in 80 mL of n-hexane is added
dropwise within 1 h a solution of Cp2Ti(CO)2 (200 mg, 0.854
mmol) in 50 mL of n-hexane. The brown precipitate of 2 is
1
isolated and washed twice with n-hexane (223 mg, 57%). H
NMR (CDCl3): δ 3.83 (m, 2H), 4.36 (m, 2H), 4.44 (m, 2H), 4.52
(m, 2H), 6.59 (s, 10H). 13C{1H} NMR (CDCl3): δ 67.92, 69.07,
69.82, 70.60, 76.10, 111.58, 113.66. UV-vis (methanol): 224,
293, 333, 405, 765 nm. Anal. Calcd for C20H18FeTiS3: C, 52.41;
H, 3.95; S, 20.99. Found: C, 51.81; H, 4.20; S, 20.58.
P r ep a r a tion of [fcS4]. To a solution of 2 (230 mg, 0.50
mmol) in 30 mL of CS2 is added a solution of SCl2 (52 mg,
0.50 mmol) in 1.6 mL of CS2. After the color has changed from
brown to orange-red the precipitated Cp2TiCl2 is filtered off
and the solution stirred with a little silica gel to bind residual
Cp2TiCl2 (color change to yellow). After filtration the solvent
is evaporated and the residue purified by column chromatog-
raphy on silica gel (mobile phase: dichloromethane/n-hexane,
1:4 v/v), yielding 42 mg of fcS4 (27%). 1H NMR (CDCl3): δ 4.41
(pt, 4H), 4.75 (pt, 4H). UV-vis (methanol): 220, 293, 392, 450
nm. Anal. Calcd for C10H8FeS4: C, 38.46; H, 2.58; S, 41.07.
Found: C, 37.83; H, 2.60; S, 40.52.
P r ep a r a tion of [fc(µ2-S)2CH2]. To a solution of fc(SH)2
(113 mg, 0.45 mmol) in 15 mL of dichloromethane are added
102 mg of solid Cp2TiCl2 (0.41 mmol) and 4.1 mL of aqueous
KOH (5%), resulting in a color change of the organic phase
from red to almost black while the aqueous phase becomes
red. After stirring at room temperature for 2 h the phases are
separated and the organic layer is dried over MgSO4. After
filtration and partial evaporation of the solvent the product
is precipitated by adding n-hexane and cooling to -55 °C,
1
resulting in a dark green solid of mp 182 °C (38 mg, 35%). H
NMR (CDCl3): δ 4.12 (s br, 4H), 4.17 (s, 2H), 4.35 (m, 4H).
In summary, we have evaluated by electrochemical
investigations the electronic effects played by the oxygen
atoms of different sulfane oxides in tri- and dithiafer-
rocenophanes. We have also shown that heterobimetallic
complexes of ferrocene with titanocene can be pre-
pared,14 which should be useful precursors for the
UV-vis (methanol): 214, 268, 414 nm. Anal. Calcd for C11H10
-
FeS2: C, 50.39; H, 3.84; S, 24.45. Found: C, 49.97; H, 3.51; S,
23.82.
(14) For other ferrocene-titanium complexes, see for example: (a)
Gibson, V. C.; Long, N. J .; Martin, J .; Soslan, G. A.; Stichbury, J . C. J .
Organomet. Chem. 1999, 590, 115. (b) Shafir, A.; Arnold, J . J . Am.
Chem. Soc. 2001, 123, 9212.
(13) (a) Hayashi, Y.; Osawa, M.; Wakatsuki, Y. J . Organomet. Chem.
1997, 542, 241. (b) Back, S.; Pritzkow, H.; Lang, H. Organometallics
1998, 17, 41.
(15) Steudel, R. Chem. Rev., in press.
(16) Togni, A.; Hobi, M.; Rihs, G.; Albinati, A.; Zanello, P.; Zech,
D.; Keller, H. Organometallics 1994, 13, 1224.

2608 Organometallics, Vol. 21, No. 13, 2002
Steudel et al.
methods (SHELXS18) and refined with anisotropic thermal
parameters for the non-hydrogen atoms (SHELXL19). Hydro-
gen positions at the ring atoms were refined with a riding
model. The drawing was created with the DIAMOND pro-
gram.20
Ta ble 2. Cr ysta l Da ta , Da ta Collection , a n d
Str u ctu r e Refin em en t for fcS2CH2
formula
C11H10FeS2
262.16
fw
color
yellow
cryst size, mm
cryst syst
space group
temp, K
wavelength, Å
a, Å
b, Å
0.82 × 0.64 × 0.46
orthorhombic
Pcab
293(2)
0.71073
Crystallographic data have been deposited at the Cambridge
Data Center and may be obtained free of charge on quoting
the depository number CCDC 175495 from CCDC, 12 Union
Road, Cambridge CB2 1EZ, UK (fax: +44-1223-336033, e-
mail: deposit@ccdc.cam.ac.uk).
9.61490(10)
11.8570(2)
C, Å
17.87610(10)
2037.94(4)
8
1.709
1.8400
1072
2.28 e 2 e 30.47
17 434
3081 (Rint ) 0.0689)
full matrix, least squares on F2
3081/0/160
Ack n ow led gm en t. This work was supported by the
Deutsche Forschungsgemeinschaft and the Verband der
Chemischen Industrie. P.Z. gratefully acknowledges the
financial support from the University of Siena (PAR
2001).
V, Å3
Z
density (calcd), g cm-3
abs coeff, mm-1
F(000)
scan range, deg
no. of reflns collected
no. of ind reflns
refinement method
no. of data/restraints/params
goodness-of-fit on F2
final R indices [I >2σ(I)]
R indices, all data
largest diff peak and hole,
e Å-3
Su p p or tin g In for m a tion Ava ila ble: Tables with bond
lengths, bond angles, torsion angles and atomic coordinates
have been deposited. This material is available free of charge
via the Internet at http://pubs.acs.org.
0.939
R1 ) 0.0328, wR2 ) 0.0898
R1 ) 0.0424, wR2 ) 0.0989
0.348, -0.308
OM020041Z
(17) Sheldrick, G. M. SADABS, Empirical Absorption Correction
Program; Go¨ttingen, 1996.
X-r a y Diffr a ction Stu d y. The details of the crystal struc-
ture determination and refinement are given in Table 2. Data
were collected on a Siemens Smart CCD diffractometer using
Mo KR radiation (λ ) 0.71069 Å). The structure was solved
after Lp and absorption correction (SADABS17) by direct
(18) Sheldrick, G. M. SHELXS-97, Program for Crystal Structure
Solution; Go¨ttingen, 1997.
(19) Sheldrick, G. M. SHELXL-97, Program for Refinement of
Crystal Structures; Go¨ttingen, 1997.
(20) Bergerhoff, G.; Brandenburg, K.; Berndt, M. DIAMOND,
Visuelles Informationssystem fu¨r Kristallstrukturen; Bonn, 1996.