Synthesis of new functionalized compounds related to π-extended tetrathiafulvalenes with quinonoidal structures bearing a ferrocene moiety

Article abstract of DOI:10.1007/s007060200074

A number of π-extended conjugated tetrathiafulvalene (TTF) analogues were synthesized as new π-donors, and their structures and physical properties were determined. UV/Vis spectra and cyclic voltammetry of the π-extended ferrocenyl donors were studied in comparison with ferrocene, ferrocenylquinone, and the parent donor. A three-electron redox behaviour was observed. The absorption spectrum of the new donor 16 showed a slight red-shift and a slight increase in intensity relative to the compared compounds.

Full text of DOI:10.1007/s007060200074

Monatshefte fuÈr Chemie 133, 1055±1066 ꢀ2002)
Synthesis of New Functionalized
Compounds Related to p-Extended
Tetrathiafulvalenes with Quinonoidal
Structures Bearinga Ferrocene Moiety
Ã
Abd El-Wareth A. O. Sarhan , Makoto Murakami, and Taeko Izumi
Department of Chemistry and Chemical Engineering, Faculty of Engineering,
Yamagata University, Yonezawa 992-8510, Japan
Summary. A number of ꢀ-extended conjugated tetrathiafulvalene ꢀTTF) analogues were synthesized
as new ꢀ-donors, and their structures and physical properties were determined. UV=Vis spectra and
cyclic voltammetry of the ꢀ-extended ferrocenyl donors were studied in comparison with ferrocene,
ferrocenylquinone, and the parent donor. A three-electron redox behaviour was observed. The ab-
sorption spectrum of the new donor 16 showed a slight red-shift and a slight increase in intensity
relative to the compared compounds.
Keywords. Ferrocenyl quinone; Electrical properties; Cyclic voltammetry; Absorption intensity.
Introduction
Recently, tetrathiafulvalenes TTFs have become an interesting topic of research
due to their highly electrical conductivity and superconducting properties [1, 2]. It
has also been reported that tetrathiafulvalenes show good ꢀ-donor properties [3].
The synthesis of two dithiole rings separated by a conjugated spacer has received
great attention as a consequence of the potential of these compounds in the prep-
aration of substances with nonlinear optical properties or as semiconductors. The
synthesis of derivatives and analogues of dithiafulvalene ꢀDTF) and tetrathiaful-
valene ꢀTTF) is of considerable interest [4, 5]. Due to the structural and electro-
chemical properties of ferrocene-containing tetrathiafulvalene derivatives, several
ferrocene-tetrathiafulvalenes were constructed as donors for conducting charge
transfer complexes. Ueno et al. have reported on the ®rst compound belonging to
this class of donor conducting materials [6]. A very similar type of donor molecules
has recently been introduced by Bryce and co-workers [7]. Several charge transfer
complexes of metal bis-arene compounds containing, among others, the familiar
organic acceptor TCNQ have been also reported. Recently, Togni et al. have syn-
thesized mono- and 1,10-disubstituted ferrocene derivatives like 1 and 2 as novel
donors for the preparation of charge transfer complexes which, structurally and
Ã
Corresponding author. E-mail: sarhan@chem.yz.yamagata-u.ac.jp

1056
A. E.-W. A. O. Sarhan et al.
Scheme 1
Scheme 2
electronically related to the TTFs, were conjugated with a ferrocene moiety [8]
ꢀScheme 1). Togni has also mentioned that none of these materials has been shown
to display physical properties superior to those of the metallocene systems [9]
ꢀScheme 1).
Extended TTF ꢀ4) derivatives like 5±8 having a p-quinodimethane structure
have been used as strong electron donors. Due to their extended conjugation they
exhibit a decrease of the intramolecular on-site Coulomb repulsion [10]. The for-
mation of monostoichiometric complexes with acceptor molecules is due to their
different sizes [11] ꢀScheme 2).
In contrast to 4 and its derivatives, the p-quinodimethane analogues of 4 form
stable dication species which constitute CT complexes with interesting electrical and
magnetic properties [11±13]. In spite of the importance of these ꢀ-extended p-
quinodimethane analogues of 4 in the search for new opto-electronic properties, the
synthesis of ꢀ-extended p-quinodimethanes connected directly to a ferrocene moiety
ꢀ3) in addition to highly conjugated TTF units has not yet been described.
Results and Discussion
Synthesis
In this work we focused on the synthesis of novel donors based on ferrocene-
tetrathiafulvalenes separated by conjugated spacers like p-benzoquinone or
anthraquinone derivatives. We used new derivatives of quinones connected directly
to the ferrocene moiety without a conjugated spacer between the quinodimethane
and ferrocene moieties. Ferrocene is known to show only a single one-electron
redox process at potentials near to the ®rst oxidation step of TTF compounds [9].
Comparison of the electrochemical properties of the new ꢀ-donors with those of

Ferrocene Containing ꢀ-Extended Tetrathiafulvalene Analogues
1057
Scheme 3
ferrocene and tetrathiafulvalene homologues previously prepared is important for
the molecular design of novel donor systems. We therefore synthesized and inves-
tigated the electronic interactions of a new ꢀ-extended donor in which the extended
TTF is directly attached to the strong electron donor ferrocene without spacer. 2-
Ferrocenylanthraquinone ꢀ11) was prepared in 21% yield via diazotation of 2-
aminoanthraquinone ꢀ9) followed by coupling with ferrocene in acetic acid at 0ꢀC
ꢀScheme 3).
Compound 11 exhibited a deep violet color, and its UV=Vis spectrum in EtOH
showed the presence of broad low-energy band at 598 nm which can be accounted
as an intramolecular charge transfer band resulting from the strong electron donor
ferrocene and the electron acceptor anthraquinone.
2-Dimethoxyphosphinyl-1,3-benzodithiole ꢀ15) was prepared following well-
established procedures from anthranilic acid ꢀ12) [14]. Thus, 2-butoxy-1,3-
benzodithiole ꢀ13) was obtained through four reaction steps. Aprotic diazotation of
anthranilic acid ꢀ12) by alkyl nitrite gave the corresponding benzendiazonium-2-
carboxylate. Its thermal decomposition to benzyne and reaction with carbon disul®de
led to the 1,3-dithiole-2-carbene and subsequently to 13 by addition of 2-methyl-
butanol which either resulted from the diazotation of 12 by alkyl nitrite or was
added prior to the reaction. 13 was reacted with HBF4 in acetic anhydride to give 1,3-
benzodithiolylium ¯uoroborate ꢀ14) in good yield. Re¯uxing of 14 with PꢀOMe)3 in
acetonitrile in presence of NaI gave 2-dimethoxyphosphinyl-1,3-benzdithiole ꢀ15) in
high yield [14] ꢀScheme 4).
Synthesis of the target molecule 16 was carried out by Wittig-Horner ole®nation
as shown in Scheme 5. The 2-ferrocenylquinone 11 was reacted with 15 in the
presence of n-BuLi at À78ꢀC in dry THF. 16 was obtained after chromatography
as orange crystals in 28% yield; in addition, the starting compound 11 was isolated
in very low yield. 17 could not be isolated in pure form and good yield; it
1
was characterized by H and 13C NMR spectroscopy and by FAB mass spectra

1058
A. E.-W. A. O. Sarhan et al.
Scheme 4
Scheme 5
‡
ꢀM : m=z ˆ 528). In addition, the unexpected racemic anthrone derivative 18 was
obtained as yellow orange crystals in 24% yield ꢀScheme 5).
The IR spectra of 16 lacked the carbonyl group of the 2-ferrocenylquinone ꢀ11)
at 1666 cmÀ1. The 13C NMR spectrum also proved the absence of a CO group.
Mass spectroscopic analysis gave the expected molecular ion peak at m=z ˆ 664.
The structure of compound 18 was determined by spectroscopic analysis. The FAB mass spectra
1
gave a molecular mass of 450, which agreed with the suggested structure. The H NMR spectrum
revealed 7 aromatic protons ꢀbesides ferrocene), butyl protons, and one hydroxy proton. The 13C
NMR spectrum showed only one carbonyl group at ꢁ ˆ 183.27 ppm. The IR spectrum indicated the
presence of a OH group ꢀꢂ ˆ 3467 cmÀ1) and a carbonyl group ꢀꢂ ˆ 1650 cmÀ1).
For comparison with the ꢀ-extended donor 16, 19 was prepared by a Wittig-
Horner reaction ꢀn-BuLi=THF, À78ꢀC) as yellow crystals in 97% yield [14c, 17]
ꢀScheme 6).

Ferrocene Containing ꢀ-Extended Tetrathiafulvalene Analogues
1059
Scheme 6
Scheme 7
2-Ferrocenyl-5-methyl-p-benzoquinone ꢀ20) was obtained in 20% overall yield
via several steps following the method reported by Izumi et al. [15]. Reaction of 20
with 2-dimethoxyphosphinyl-1,3-benzodithiole ꢀ15) using n-BuLi in THF at À78ꢀC
followed by stirring at room temperature overnight gave a mixture of unidenti®ed
products; neither the dithiafulvalenes 21 and 22 nor the tetrathiafulvalene 23 were
formed. Several other attempts to synthesize the TTF 23 were also unsuccessful
ꢀScheme 7).
Presently, attempts are made to synthesize 2-ferrocenyl-1,4-benzoquinone, 2-
ferrocenyl-1,4-naphthoquinone, and 6-ferrocenyl-1,4-naphthoquinone and to react
them with 15 to obtain different ꢀ-extended donors for electrochemical studies.
Electrochemical properties
The electrochemical properties of 16, 19, and 11 in comparison to ferrocene ꢀ3)
were investigated by cyclic voltammetry in CH2Cl2 in the presence of 0.1 M tetra-
n-butylammonium perchlorate ꢀTBAP) as the supporting electrolyte using a Pt
‡
working electrode and a Ag =AgCl reference electrode at ambient temperature.
The donors 16 and 19 displayed one pair of redox waves corresponding to a one-
electron transfer process; the redox potentials are summarized in Table 1.

1060
A. E.-W. A. O. Sarhan et al.
Table 1. Formal electrode potentials for the redox changes in CH2Cl2; scan rate: 20 mV Á sÀ1
supporting electrolyte: TBAP ꢀ0.1 M)
;
Oxidation ꢀE1=2=V)
Reduction ꢀE1=2=V)
3
16
19
‡ 0.51
‡ 0.58
‡ 0.67
‡ 0.54
‡ 0.60
±
Fig. 1. Cyclic voltammograms of 3, 16 and 19 in CH2Cl2 on a platinum electrode; c ˆ 1.0  10À3 M,
scan rate: 20 mV Á sÀ1, base electrolyte: TBAP, 0.1 M
Comparison of the redox potentials reveals that the oxidation potential of 16
is different from the oxidation potential of 19: E1=2ꢀ19)ÀE1=2ꢀ16) ˆ 0.09 V.
E
1=2ꢀ19)ÀE1=2ꢀ16) is a measure of the on-site Coulomb repulsion and suggests
the direct connection of the ferrocene to the ꢀ-extended donor 16, thereby chang-
ing the electron donating ability of the donor. Considering all variables, 16 ex-
hibited a single electrochemically reversible three-electron oxidation process at
ambient temperature, whereas 19 showed a single electrochemically irreversible
two-electron oxidation process under the same conditions ꢀFig. 1).
Increasing the scan rates gave the same peak pattern, but resulted in a signi®-
cant increase of Epa and a decrease of Epc, indicative of a slow heterogeneous
electron transfer process as shown in Fig. 2.
A striking feature of 16 is that this molecule undergoes a three-electron redox
process observed as a single wave. The oxidation peaks could not be resolved by
reducing the scan rate from 600 to 20 mV Á sÀ1 ꢀFig. 2) or by using different solvents
ꢀFig. 3). The redox wave of 16 is chemically reversible but electrochemically
irreversible; the peak-to-peak potential varies from 190 to 100 mV depending on
scan rate and solvent. The oxidation peak potential in CH3CN=CH2Cl2 was lower
than that in either CH2Cl2 or THF ꢀCH3CN=CH2Cl2 < CH2Cl2 < THF) on the same
electrodes at a scan rate of 20 mV Á sÀ1 ꢀFig. 3).
The oxidation wave of ferrocene is reversible and occurs at the potential of the
FeII=III redox couple. The coalescence of the two different oxidation processes into
one reveals the in¯uence of the ferrocene moiety and the quinonoid structure

Ferrocene Containing ꢀ-Extended Tetrathiafulvalene Analogues
1061
Fig. 2. Cyclic voltammograms of 16 in CH2Cl2 on a Pt electrode; c ˆ 1.0  10À3 M, scan rate: 20±
600 mV Á sÀ1, base electrolyte: TBAP, 0.1 M
Fig. 3. Cyclic voltammograms of 16 in CH2Cl2, THF and CH3CN=CH2Cl2 on a Pt electrode;
c ˆ 1.0  10À3 M, scan rate: 20 mV Á sÀ1, base electrolyte: TBAP, 0.1 M
between the two 1,3-dithiole rings. Three one-electron processes lead directly to
‡
the formation of a tricationic state Fc -exTTF2 ‡ as described in the literature
[9b]. The electrochemical data of 16 recorded in different solvents are shown in
Fig. 3 and Table 2.
Bryce et al. [11] have reported that the X-ray analysis of the analogue of 19 was found to show a
highly distorted geometry in the neutral state, whereas Liu et al. [10b] have suggested that this
geometric distortion could be hold responsible for the coalescence of the oxidation wave of the
anthracene moiety with that of the two 1,3-dithiole rings.

1062
A. E.-W. A. O. Sarhan et al.
Table 2. Formal electrode potentials for the redox changes of the ꢀ-extended donor 16 on a Pt
electrode; scan rate: 20 mV Á sÀ1, base electrolyte: TBAP ꢀ0.1 M)
Solvent
Oxidation ꢀE1=2=V)
Reduction ꢀE1=2=V)
CH3CN=CH2Cl2
THF
‡ 0.50
‡ 0.63
‡ 0.58
‡ 0.53
‡ 0.57
‡ 0.60
CH2Cl2
The coalescence behaviour of 16 indicated a planar aromatic hydrocarbon
skeleton in the extended TTF moiety. It is known that these unstable radical cations
easily form stable dications upon further oxidation in which the Coulomb repulsion
is remarkably decreased [1, 10b, 12b].
Electronic spectroscopy
As shown in Fig. 4, the UV=Vis spectra of 16 and comparable compounds in
ethanol are mainly dominated by the absorption of the exTTF moiety in the region
of 220±250 nm. Because of the weak intensity of the ferrocene spectrum, the log"
scale is used for comparison. The absorptions of 16 were observed at 241 ꢀlog" ˆ
4.78), 352 ꢀlog" ˆ 4.32), and 416 ꢀlog" ˆ 4.47) nm. Upon comparison of the ꢃmax
values of donors 16 and 19, a slight red-shift and an increase of the absorption
intensities were observed. This means that ground-state intramolecular electronic
interactions are observed in the case of 16 ꢀTable 3).
To account for the electrochemical observations, the molecular geometry of 16
was optimized using Win-MOPAC at the AM1 level. The minimum energy con-
formation of 16 is shown in Figure 5. The donor molecule adopts a butter¯y shape
with the central ring in a boat conformation, which is in good agreement with data
Fig. 4. UV=Vis spectra of 3, 11, 16, and 19 in EtOH ꢀc ˆ 4.05  10À5 M)

Ferrocene Containing ꢀ-Extended Tetrathiafulvalene Analogues
1063
Fig. 5. AM1 optimized geometry of 16
Table 3. Absorption maxima in the electronic spectra of quinones 11 and 20 and donors 16 and 19 in
EtOH
ꢃmax=nm ꢀlog")
3
20
11
16
19
440 ꢀ2.01), 326 ꢀ1.77)
396 ꢀ2.82), 276 ꢀ4.01)
562 ꢀ2.77), 363 ꢀ3.4), 272 ꢀ4.01), 250 ꢀ4.06)
416 ꢀ4.47), 352 ꢀ4.32), 241 ꢀ4.78)
410 ꢀ4.15), 345 ꢀ3.95), 234 ꢀ4.32)
reported for analogues published recently [1, 8, 9a]. The conjugation between
the donor and the ferrocene moiety ꢀꢄ ˆ 130.1ꢀ) is rather pronounced.
Conclusions
The novel compound 16 was synthesized as a new ꢀ-donor, and its structure was
con®rmed by spectroscopic analyses. The electrochemical properties of 16 were
studied using cyclic voltammetry at ambient temperatures on a Pt working electrode
with TBAP as the supporting electrolyte. A three-electron redox behavior was
observed as a single wave. The advantage of introducing ferrocene into the donor is
that ferrocene has only a single one-electron redox process. Considering the fact that
the ꢀ-extended donor 16 contains two different types of donor moieties, it was
important to determine which is easier to oxidize by changing the solvent or using
different scan rates. A single quasireversible three-electron oxidation process was
observed in CH2Cl2, THF, or a mixture of CH2Cl2 and CH3CN, whereas 19 exhibited
a single electrochemically irreversible two-electron oxidation process under the
same conditions. It is important to recognize that both ferrocene ꢀ3) and 16 showed
typical electrochemically reversible redox processes with redox potentials. A com-
parison of the absorption bands of 16 and 19 showed a slight red-shift and a slight
increase in the absorption intensities for 19.
Experimental
Solvents were distilled before use. 2-Aminoanthraquinone is commercially available; ferrocene was
prepared according to Ref. [19]. 2-Ferrocenyl-5-methyl-1,4-benzoquinone ꢀ20) was obtained
according to a method previously described [15]. Melting points were recorded on a Gallencamp

1064
A. E.-W. A. O. Sarhan et al.
melting point apparatus and are uncorrected. IR spectra were measured on a Hitachi 260-10
spectrometer, 1H and 13C NMR spectra on a Varian Inova 500 MHz spectrometer at room temperature.
Chemical shifts are given in ꢁ units ꢀppm) relative to internal TMS; J values are given in Hz. CDCl3 was
used as solvent unless otherwise stated. Mass spectra were obtained using a Jeol JMS-AX505HA
instrument. UV=Vis Spectra were detected using a Hitashi U-2010 spectrophotometer. Cyclic
voltammetry was performed on a Lawrence Model CS-1090=Model CS-1087 system. Column
chromatography was conducted on silica gel 60 ꢀ230±400 mesh ASTM).
2-Ferrocenylanthraquinone ꢀ11; C24H16O2Fe)
A solution of 2.8 g ꢀ40 mmol) NaNO2 in 40 cm3 H2O was added to a suspension of 8.0 g ꢀ36.0 mmol)
2-aminoanthraquinone ꢀ9) in 200 cm3 conc. HCl at 0ꢀC. The formed diazonium salt was added to a
solution of 6.6 g ꢀ35.0 mmol) ferrocene in 200 cm3 acetic acid under a stream of N2 at 0ꢀC. The
reaction mixture was stirred at room temperature for 10 h and then left overnight. The precipitate was
collected by ®ltration, washed with EtOH, and dried to give 10.5 g of a dark brown product.
Chromatography on silica gel ꢀbenzene) afforded yellow crystals of anthraquinone in the early
fractions, followed by deep-violet crystals of 11 ꢀ3.0 g ꢀ21%), m.p.: 141±143ꢀC). The ®nal fraction
‡
consisted of 0.4 g deep-gray crystals of 1,10-dianthraquinonylferrocene ꢀM : m=z ˆ 598).
IR ꢀKBr): ꢂ ˆ 3072w, 2362m, 1666s, 1589s, 1448s, 1409m, 1328s, 1166m, 1105s, 711s,
669s cmÀ1; 1H NMR ꢀCDCl3, 500 MHz, ꢁ): 8.3 ꢀm, 3 aromatic H), 8.2 ꢀd, J ˆ 8.5 Hz, 1 aromatic H),
7.85 ꢀm, 3 aromatic H), 4.86 ꢀs, 2 ferrocene H), 4.50 ꢀs, 2 ferrocene H), 4.08 ꢀs, 5H, ferrocene H) ppm;
13C NMR ꢀCDCl3, 125 MHz, ꢁ): 183.64, 182.79 ꢀ2 CO), 147.60 ꢀaromatic C), 134.15±123.71
ꢀaromatic C), 82.13, 70.59, 70.04, 67.24 ꢀferrocene C) ppm; MS: m=z ꢀ%) ˆ 392 ꢀ100).
2-)3-Methylbutoxy)-1,3-benzdithiol ꢀ13; C12H16OS2)
The method previously reported by J. Nakayama [14a] was modi®ed as described. A sample of 21 g
anthranilic acid ꢀ1; 0.15 mol) was added portionwise over a period of 40 min to a stirred and gently
re¯uxing solution of 21 g ꢀ0.18 mol) isoamyl nitrite, 26.5 g ꢀ0.3 mol) 3-methylbutanol, and 75 cm3 CS2
in 300 cm3 1,2-dichloroethane:chloroform ˆ 1:1. After the addition was completed, the mixture was
re¯uxed for one further hour. The resulting red reaction mixture was evaporated under vacuum, and the
residue was washed successively with H2O ꢀ5x) and dried over Na2SO4. Solvent and excess reagents
were removed under reduced pressure, and the red viscous oily residue was puri®ed by column
chromatography using hexane as eluent to give pale yellow oils of 13 in the ®rst fractions ꢀ28.6 g, 77%).
Increasing the polarity of the eluent by adding 30% CHCl3 led to the isolation of unidenti®able
polymeric material.
1,3-Benzodithiolium ¯uorborate ꢀ14; C7H5S2BF4)
To a stirred and ice-cooled solution of 3.93 g ꢀ16.0 mmol) 13 in 50 cm3 Ac2O, 7.0 g HBF4 ꢀ79.7 mmol)
was added dropwise over 20 min. After stirring at room temperature for 20 min, anhydrous diethyl
ether ꢀ100 cm3) was added to the mixture, and the resulting precipitate was collected by ®ltration
and washed with 100 cm3 anhydrous diethyl ether to give 2.0 g ꢀ51%) of 14 as colorless crystals. M.p.:
148±150ꢀC ꢀRef. [14b]: 149±150ꢀC ꢀdec.)).
2-Dimethoxyphosphoryl-2-H-1,3-benzdithin ꢀ15; C9H11PO3S2)
A mixture of 0.935 cm3 ꢀ8.0 mmol) PꢀOCH3)3 and 1.2 g ꢀ8.0 mmol) NaI were added successively to a
stirred solution of 1.8 g ꢀ7.5 mmol) 14 in 60 cm3 dry CH3CN at room temperature under a stream of N2.
The mixture was stirred for further 2.5 h at room temperature, the solvent was removed under vacuum,
and H2O was added. The colorless crystals formed were ®ltered off and washed with H2O ꢀ3x) to give
1.6 g ꢀ81.6%) of 15 as colorless crystals.

Ferrocene Containing ꢀ-Extended Tetrathiafulvalene Analogues
1065
M.p.: 121±123ꢀC ꢀRef. [14c]: 122±123ꢀC); IR ꢀKBr): ꢂ ˆ 3008m, 2954s, 2898s, 2850s, 1625w,
1565w, 1442s, 1255s, 1207s, 1180s, 116s, 1027s, 759s, 740s cmÀ1; 1H NMR ꢀCDCl3, 500 MHz, ꢁ):
7.20 ꢀm, 2H, aromatic H), 7.03 ꢀm, 2H, aromatic H), 4.88 ꢀd, J ˆ 5 Hz, CH2), 3.8 ꢀs, CH3), 3.77
ꢀs, CH3); 13C NMR ꢀCDCl3, 125 MHz, ꢁ): 136.52 ꢀaromatic C), 126.1 ꢀaromatic CH), 122.22
ꢀaromatic CH), 54.80 ꢀCH2), 44.58 ꢀCH3), 43.31 ꢀCH3); FAB-MS: m=z ꢀ%) ˆ 262 ꢀ87).
2-Ferrocenyl-9,10-bis-)1,3-benzdithiol-2-ylidene)-9,10-dihydroanthracene
ꢀ16; C38H24S4Fe)
A sample of 286 mg ꢀ1.1 mmol) 15 was stirred in 40 cm3 dry THF under a stream of N2 at À78ꢀC.
1.2 cm3 n-BuLi solution ꢀ1.6 M in hexane) were added, and the mixture was stirred for 15 min. A
solution of 203 mg ꢀ0.55 mmol) 2-ferrocenylanthraquinone ꢀ11) in 50 cm3 dry THF was added
portionwise. The temperature of the mixture was raised to room temperature, and it was kept
overnight with stirring. The THF was removed under vacuum, and the residue was washed with H2O
and extracted with CHCl3 and dried over Na2SO4. The crude oily product was chromatographed on
silica gel using CHCl3 : hexane ˆ 1 : 2 to give 40 mg of yellow crystals of an unknown compound in
the early fractions, followed by 100 mg of yellow orange crystals of 16 ꢀ28%). With
CHCl3:hexane ˆ 1:1, 108 mg of orange crystals of the racemic anthrone 18 were obtained ꢀ24%).
M.p.: 139±143ꢀC; IR ꢀKBr): ꢂ ˆ 3050w, 2960m, 2923s, 1656m, 1567m, 1523s, 1446s, 1430s,
1261s, 1103s, 1027s, 806s, 736s cmÀ1; 1H NMR ꢀCDCl3, 500 MHz, ꢁ): 7.87 ꢀd, J ˆ 1.5 Hz, 1 aromatic
H), 7.77±7.75 ꢀm, 2 aromatic H), 7.65 ꢀd, J ˆ 8 Hz, 1 aromatic H), 7.44 ꢀdd, J ˆ 8 Hz, J ˆ 1.5 Hz, 1H,
aromatic H), 7.38 ꢀm, 2 aromatic H), 7.23±7.19 ꢀm, 4 aromatic H), 7.08±7.06 ꢀm, 4 aromatic H),
4.776±4.74 ꢀdd, J ˆ 6 Hz, J ˆ 1 Hz, 2 ferrocene H), 4.38±4.36 ꢀm, 2 ferrocene H), 4.15 ꢀs, 5 ferrocene
H) ppm; 13C NMR ꢀCDCl3, 125 MHz, ꢁ): 138.62±121.89 ꢀaromatic C and CH), 85.90 ꢀferrocene C),
70.61, 70.10, 70.00, 67.92, 67.09 ꢀferrocene C) ppm; FAB-MS: m=z ꢀ%) ˆ 664 ꢀ13).
18: M.p.: 151±152ꢀC; IR ꢀKBr): ꢂ ˆ 3467s, 3093w, 3066w, 2954s, 2861s, 1650s, 1600s, 1455s,
1380s, 1326s, 1037s, 765s, 696s cmÀ1; 1H NMR ꢀCDCl3, 500 MHz, ꢁ): 8.25 ꢀd, J ˆ 7.5 Hz, 1 aromatic
H), 8.15 ꢀdd, J ˆ 8 Hz, J ˆ 1 Hz, 1H, aromatic H), 7.97 ꢀd, J ˆ 1.5 Hz, 1 aromatic H), 7.92 ꢀd, J ˆ 8 Hz,
1 aromatic H), 7.68 ꢀdt, J ˆ 1.5 Hz, J ˆ 7.5 Hz, 1 aromatic H), 7.55 ꢀdd, J ˆ 2 Hz, J ˆ 7.5 Hz, 1
aromatic H), 7.50 ꢀdt, J ˆ 1.5 Hz, J ˆ 7.5 Hz, 1 aromatic H), 4.83±4.79 ꢀm, 2 ferrocene H), 4.45 ꢀm, 2
ferrocene H), 4.04 ꢀs, 5 ferrocene H), 2.45 ꢀs, 1 OH), 2.06±2.03 ꢀm, CH2), 1.05±1.02 ꢀm, CH2), 0.72 ꢀm,
CH2), 0.65±0.63 ꢀt, J ˆ 7.5 Hz, CH3) ppm; 13C NMR ꢀCDCl3, 125 MHz, ꢁ): 183.27 ꢀCO), 147.57,
147.31, 146.34, 133.48, 131.13 ꢀaromatic C), 128.53, 128.03, 127.15, 126.74, 125.88, 125.48, 122.73
ꢀaromatic CH), 83.15 ꢀferrocene C), 73.01, 70.20, 70.10, 69.94 ꢀferrocene CH), 48.44 ꢀCH2), 26.14
ꢀCH2), 22.47 ꢀCH2), 13.74 ꢀCH3) ppm; FAB-MS: m=z ꢀ%) ˆ 450 ꢀ100).
9,10-Bis-)1,3-benzdithiol-2-ylidene)-9,10-dihydroanthracene ꢀ19; C28H16S4)
According to the method described for synthesis of 16, 19 was obtained in 98% yield.
IR ꢀKBr): ꢂ ˆ 3052w, 2919w, 1600w, 1567s, 1521s, 1446s, 1430s, 1282s, 1157m, 1122m, 754s,
1
674s cmÀ1; H NMR ꢀCDCl3, 200 MHz, ꢁ): 7.74 ꢀm, 4 aromatic H), 7.37 ꢀm, 4 aromatic H), 7.27±
7.16 ꢀm, 4 aromatic H), 7.07 ꢀm, 4 aromatic H) ppm; 13C NMR ꢀCDCl3, 50 MHz, ꢁ): 136.71, 135.61,
132.51 ꢀaromatic C, anthracene ring), 126.80, 126.20, 126.14 ꢀaromatic C, benzdithiole C), 124.23,
121.42 ꢀCˆC) ppm; FAB-MS: m=z ꢀ%) ˆ 480 ꢀ23).
Acknowledgments
We are grateful to Fujitsu Co. Ltd. for an offer of `Win MOPAC'. This work was partially supported
by a Grant-Aid for Scienti®c Research ꢀNo. 12650844) from the Ministry of Education, Sciences,
Sports, and Culture ꢀJapan).

1066 A. E.-W. A. O. Sarhan et al.: Ferrocene Containing ꢀ-Extended Tetrathiafulvalene Analogues
References
[1] Martin N, Sanchez L, Seoane C, Orti E, Viruela PM, Veruela R ꢀ1998) J Org Chem 63: 1268
[2] Yoshida Z, Kawase T, Awaji H, Sugimoto I, Sugimoto T, Yoneda S ꢀ1983) Tetrahedron Lett 24:
3469
[3] Belyasmine A, Gorgues A, Jubault M ꢀ1991) Synthetic Metals 41±43: 2323
[4] Moore AJ, Bryce MR ꢀ1991) Synthesis 26 and references cited therein
[5] Martin N, Sanchez L, Guldi DM ꢀ2000) Chem Commun 113
[6] Ueno Y, Sano H, Okawara M ꢀ1980) J Chem Soc Chem Commun 28
[7] Moore AJ, Skabara PJ, Bryce MR, Batsanov AS, Howard JAK, Daley STAK ꢀ1993) J Chem Soc
Chem Commun 417
[8] Togni A, Hobi M, Rihs G, Rist G, Albinati A, Zanello P, Zech D, Keller H ꢀ1994) Organo-
metallics 13: 1224
[9] a) Togni A ꢀ1995) Ferrocene-Containing Charge Transfer Complexes. Conducting and Magnetic
Materials. In: Togni A, Hayashi T ꢀeds) Ferrocenes. VCH, Weinheim, p 434; b) Liu S, Perez I,
Martin N, Echegoyen L ꢀ2000) J Org Chem 65: 9092
ꢀ
ꢁ
[10] a) Martin N, Perez I, Sanchez L, Seoane C ꢀ1997) J Org Chem 62: 870; b) Yamashita Y,
Kobayashi Y, Migashi T ꢀ1989) Angew Chem Int Ed Engl 28: 1052; c) Kitamura C, Tanaka S,
Yamashita Y ꢀ1996) Adv Mater 8: 570
[11] Bryce MR, Moore AJ, Hasan M, Ashwell GJ, Fraser AT, Clegg W, Hursthouse MB, Karaulov AI
ꢀ1990) Angew Chem Int Ed Engl 29: 1450
[12] a) Bryce MR, Moore AJ ꢀ1988) Synthetic Metals 25: 203; b) Bryce MR, Cof®n MA, Hursthouse

MB, Karaulov AI, Mullen K, Scheich H ꢀ1991) Tetrahedron Lett 32: 6029; c) Bryce MR, Moore
AJ ꢀ1991) J Chem Soc Perkin Trans 1, 157
ꢀ
[13] a) Godbert N, Batsanov AS, Bryce MR, Howard JAK ꢀ2001) J Org Chem 66: 713; b) Perez I, Liu
S, Martin N, Echegoyen L ꢀ2000) J Org Chem 65: 3796; c) Lorcy D, Guerin D, Boubekeur K,
Carlier R, Hascoat P, Tallee A, Robert A ꢀ2000) J Chem Soc Perkin Trans 1, 2719
[14] a) Nakayama J ꢀ1975) Synthesis 38; b) Nakayama J, Fujiwara K, Hoshino M ꢀ1975) Chem Lett
1099; c) Akiba K, Ishikawa K, Inamoto N ꢀ1978) Bull Chem Soc Jpn 51: 2674
[15] Kasahara A, Izumi T, Ogata H, Tano S, Ito Y, Fujisawa T, Ogata T ꢀ1985) Bull Yamagata Univ
ꢀEng) 18: 125
[16] Benitez FM, Grunwell JR ꢀ1978) J Org Chem 43: 2917
[17] Yamashita Y, Miashi T ꢀ1988) Chem Lett 661
[18] Bryce MR, Batsanov AS, Finn T, Hanse TK, Howard JAK, Kamenjicki M, Lednev IK, Asher SA
ꢀ2000) Chem Commun 295
[19] Wilkinson G ꢀ1963) Org Synth 4: 473
Received September 19, 2001. Accepted )revised) October 23, 2001