Preparation and optical and electrochemical properties of octaethylphthalocyanines fused with several tetrathiafulvalene units

Article abstract of DOI:10.1002/hc.20694

3,6-Diethylphthalonitrile (3) with a tetrathiafulvalene (TTF) unit at 4,5-positions was prepared from 4,5-xylylenedithio-3,6-diethylphthalonitrile (1a) via elimination of the xylylene group, connection of a carbonyl group to benzenedithiolate generated, and condensation of 4,5-bis(methylthio)-1,3- dithiole-2-thione with benzo-1,3-dithiole-2-one (2-O) produced. A 1:1 mixture of phthalonitrile (3) and 4,5-bis(benzylthio)-3,6-diethylphthalonitrile (1b) was treated with lithium in n-hexanol at 120°C to produce hexakis (benzylthio)mono(tetrathiafulvaleno)phthalocyanine (5), tetrakis(benzylthio) bis(tetrathiafulvaleno)phthalocyanine (6), and bis(benzylthio) tris(tetrathiafulvaleno)phthalocyanine (7). The structures of 5, 6, and 7 were determined by ¹H NMR, FAB MS, MALDI-TOF MS (matrix assisted laser desorption ionization time-of-flight mass spectrometry), and UV - vis spectroscopy. Compound 6 is a mixture of trans and cis isomers (6-trans and 6-cis). The UV - vis spectrum of 5 measured in chloroform changed by addition of trifluoroacetic acid (TFA). The Q band absorption at λ_max = 755 nm (chloroform) decreased in intensity and resulted in a new absorption at λ_max = 740 nm (chloroform/TFA). The electrochemical properties of 5, 6, and 7 were determined by cyclic voltammetry using Ag/AgNO₃ as a reference electrode. Copyright

Full text of DOI:10.1002/hc.20694

Heteroatom Chemistry
Volume 22, Number 5, 2011
Preparation and Optical and Electrochemical
Properties of Octaethylphthalocyanines Fused
with Several Tetrathiafulvalene Units
Takeshi Kimura, Dai Watanabe, and Toshiharu Namauo
Center for Instrumental Analysis, Iwate University, Morioka, Iwate 020-8551, Japan
Received 7 December 2010; revised 25 January 2011
Chem 22:605–611, 2011; View this article online at
ABSTRACT: 3,6-Diethylphthalonitrile (3) with
wileyonlinelibrary.com. DOI 10.1002/hc.20694
a
tetrathiafulvalene (TTF) unit at 4,5-positions
was prepared from 4,5-xylylenedithio-3,6-
diethylphthalonitrile (1a) via elimination of the
xylylene group, connection of a carbonyl group
to benzenedithiolate generated, and condensation
of 4,5-bis(methylthio)-1,3-dithiole-2-thione with
INTRODUCTION
Phthalocyanines and related compounds have at-
tracted considerable attention for their actual and
potential applications in many fields including
catalysis, new functional materials, and sensitiz-
ers for photodynamic therapy [1–3]. It is signifi-
cant that Q-band absorption lies at the near in-
frared region to apply these molecules to new
functional materials. Redshift of the Q-band ab-
sorption of phthalocyanines can be efficiently per-
formed by attaching substituents at the α-positions
of the macrocycles [4]. Introducing several het-
eroatoms in the benzene rings of phthalocyanine
is also a procedure for improving its characteris-
tics [5]. As a related study, we recently reported the
preparation of octakis(benzylthio)phthalocyanine
[PcSBn] and its selenium derivative [6]. Fur-
thermore, tetrakis(trithiolo)phthalocyanines and
double-decker phthalocyanine were prepared from
tetrakis(o-xylylenedithio)phthalocyanines and oc-
takis(methylthio)phthalocyaninato titanium (IV) ox-
ide, respectively [7].
benzo-1,3-dithiole-2-one (2-O) produced.
A
1:1
mixture of phthalonitrile (3) and 4,5-bis(benzylthio)-
3,6-diethylphthalonitrile (1b) was treated with
lithium in n-hexanol at 120◦C to produce hexakis
(benzylthio)mono(tetrathiafulvaleno)phthalocyanine
(5), tetrakis(benzylthio)bis(tetrathiafulvaleno)phtha-
locyanine (6), and bis(benzylthio)tris(tetrathiaful-
valeno)phthalocyanine (7). The structures of 5, 6,
and 7 were determined by 1H NMR, FAB MS,
MALDI-TOF MS (matrix assisted laser desorption
ionization time-of-flight mass spectrometry), and
UV–vis spectroscopy. Compound 6 is a mixture of
trans and cis isomers (6-trans and 6-cis). The UV–vis
spectrum of 5 measured in chloroform changed by
addition of trifluoroacetic acid (TFA). The Q band
absorption at λmax = 755 nm (chloroform) decreased
in intensity and resulted in a new absorption at
λmax = 740 nm (chloroform/TFA). The electrochem-
ical properties of 5, 6, and 7 were determined by
cyclic voltammetry using Ag/AgNO3 as a reference
ꢀ
C
On the other hand, tetrathiafulvalene (TTF) has
been known to be an excellent electron donor and
has been applied to a variety of functional substances
[8]. There are several reports that the TTF units are
combined with phthalocyanines by means of con-
necting them through some linkers in the peripheral
electrode.
2011 Wiley Periodicals, Inc. Heteroatom
Correspondence to: Takeshi Kimura; e-mail: kimura@
iwate-u.ac.jp.
c
ꢀ
2011 Wiley Periodicals, Inc.
605

606 Kimura, Watanabe, and Namauo
or axial directions [9]. In contrast, Becher reported
that porphyrin and calixphyrin derivatives fused
with one or four TTF units [10], whereas Decurtins
prepared phthalocyanines with four TTF scaffolds
[11]. Recently, unsymmetrically substituted phthalo-
cyanine with one TTF part was reported [12]. To pre-
pare phthalocyanine with eight alkyl groups at the
α-positions and several TTF units at the β-positions,
3,6-diethylphthalonitrile (3) with the TTF skele-
ton at 4,5-positions was prepared and mixed with
4,5-bis(benzylthio)-3,6-diethylphthalonitrile (1b) in
a 1:1 ratio and treated with lithium in n-hexanol.
This paper reports the preparation, structure deter-
mination, and optical and electrochemical proper-
ties of unsymmetrically substituted phthalocyanines
with eight ethyl groups at the α-positions and one
through three TTF units at the β-positions.
Et
S
S
NC
NC
Et
1a
AlCl3/toluene, 2 h
X
: 79%
: 61%
X = O
N
N
N
N
X = S
Reflux,1 h
Et
Et
Et
NC
NC
NC
NC
SBn
SBn
S
S
AlCl3/toluene, 2 h
X
S
N
N
N
N
Et
1b
2-O (X = O)
2-S
60°C, 30 min
(X = S)
48%
2
SMe
SMe
S
S
Y
P(OEt)3, 120°C, 3 h
RESULTS AND DISCUSSION
Et
Et
Et
Et
Et
As starting compounds, 4,5-xylylenedithio-3,6-
diethylphthalonitrile (1a) and 4,5-bis(benzylthio)-
3,6-diethylphthalonitrile (1b) were prepared from
1,4-diethyltetrabromobenzene via several step reac-
tions by the procedure reported previously [6,7].
Compound 1a was treated with AlCl3 in toluene at
room temperature and then with carbonyldiimida-
zole or thiocarbonyldiimidazole at reflux tempera-
ture, which gave benzo-1,3-dithiole-2-one (2-O) and
benzo-1,3-dithiole-2-thione (2-S) in 79% and 61%
yields, respectively (Scheme 1). Similarly, 2-S was
prepared from 1b in 48% yield on treatment with
AlCl3 and thiocarbonyldiimidazole. Compound 2-O
was further treated with 4,5-bis(methylthio)-1,3-
dithiole-2-thione in triethylphosphite at 120◦C for
4 h to produce phthalonitrile (3) with the TTF unit
in 65% yield as red-orange crystals, whereas 2-S
gave 3 in 28% yield after the reaction with 4,5-
bis(methylthio)-1,3-dithiole-2-one under similar re-
action conditions. In these treatments, tetracyan-
odibenzotetrathiafulvalene (4) was produced by the
self-condensation of 2-O or 2-S in 10% and 11%
yields, respectively. The 1H NMR spectrum of 4
can be measured in chloroform-d at room tempera-
ture, but the solubility of the compound is not high
enough in the usual organic solvents.
CN
CN
NC
SMe
SMe
NC
NC
S
S
S
S
S
S
+
S
S
NC
Et
4
3
X = O, Y = S: 3 (65%), 4 (10%)
X = S, Y = O: 3 (28%), 4 (11%)
SCHEME 1
hexakis(benzylthio)mono(tetrathiafulvaleno)phtha -
locyanine (5) in 2% yield together with tetrakis(ben-
zylthio)bis(tetrathiafulvaleno)phthalocyanine
(6)
and bis(benzylthio)tris(tetrathiafulvaleno) phthalo-
cyanine (7) in 4% and 7% yields, respectively. In this
reaction, tetrakis(tetrathiafulvaleno)phthalocyanine
was not obtained. In the 1H NMR spectrum, 5 shows
two broadened and complex triplet signals for the
eight methyl groups in a 1:3 integral ratio, two
broadened signals for the eight methylene groups
in a 1:3 integral ratio, one singlet peak for the six
benzylthio groups, and one singlet peak for the two
methylthio groups, implying that 5 has one TTF
unit and six benzylthio groups on the peripheral
positions.
Although three approaches are known for
preparing unsymmetrically substituted phthalo-
cyanines [13–15], we used the statistical pro-
cedure. Compound 3 was mixed with 1b in a
1:1 ratio and treated with lithium in n-hexanol
at 120◦C for 3 h (Scheme 2). The blue-green
solid that precipitated in the solution was
filtered, dried, and purified by silica gel and
Bio-beads column chromatography, which gave
If unsymmetrically substituted phthalocyanine
consists of two different types of benzopyrrole
components (A) and (B) in a 1:1 ratio, the prod-
uct is a mixture of the ABAB (trans) isomer
and the AABB (cis) isomer, which cannot be
isolated from each other [13]. Since 6 has two
TTF units on the macrocycle, it should consist
of two isomers, 2,3,16,17-tetrakis(benzylthio) bis-
(tetrathiafulvaleno)phthalocyanine (6-trans) and
Heteroatom Chemistry DOI 10.1002/hc

Preparation and Optical and Electrochemical Properties of Octaethylphthalocyanines fused with TTF Units 607
spectrum of 7 at 50◦C showed two broadened triplet
Et
Et
SMe
SMe
NC
NC
NC
NC
SBn
SBn
signals for the eight methyl groups in a 3:1 integral
ratio, two broadened signals for the eight methylene
groups in a 3:1 integral ratio, one singlet peak for
the two benzylthio groups, and one singlet peak for
the six methylthio groups. The results suggest that
7 has three TTF units and two benzylthio groups
on the peripheral positions and possesses aggrega-
tive properties in solution at room temperature. The
structures of 5 and 6 were finally determined with
MALDI-TOF MS (matrix assisted laser desorption
ionization time-of-flight mass spectrometry): m/z =
1740.59 [M+] for 5 and m/z = 1765.14 [M+] for
6. Compound 7 showed the molecular ion peak at
1788.1 [MH+] by FAB MS measurement.
S
S
S
S
+
Et
3
Et
1b
Li/n-hexanol
120°C, 3 h
R1S
R1S
SR2
SR2
X
S
SBn
SBn
Et
Et
β
Et
Et
S
α
N
N
β
N
Et
Et
α
N
NH
Et
Et
N
NH
N
N
+
N
N
HN
N
Et
Et
HN
N
Et
SBn
Et
N
SBn
S
BnS
UV–Visible Absorption Spectroscopy
Et
Et
Et
Et
5
S
SBn
SBn
BnS
X
6
The absorption wavelengths and molar extinction
coefficients of 5, 6, and 7 were determined by UV–vis
spectroscopy (Fig. 1 and Table 1). It is expected that
the shape of absorption of the Q band is different
between the symmetric phthalocyanine and the
unsymmetric one and between the phthalocyanines
with the AABB (cis) form and the ABAB (trans)
form [16]. Interestingly although both 5 and 7 have
an unsymmetrical structure, their absorption wave-
lengths, shapes, and molar extinction coefficients
are similar to those of symmetric phthalocyanine,
2%
R1 = Bn, R2
or
=
(trans)
(cis)
X
X
2 = Bn, R1
=
X
R
X
S
S
Et
Et
4%
S
S
N
Et
Et
N
NH
SMe
SMe
N
N
S
+
X:
HN
N
S
Et
Et
S
N
7
SBn
SBn
Et
Et
S
X
7%
PcSBn (λmax = 755.0 nm, log ε = 5.1); 5 (λmax
=
755.0 nm, log ε = 5.10); 7 (λmax = 757.0 nm, log ε =
5.14). The absorption of phthalocyanine (6), which
would be a mixture of cis and trans isomers is also
similar to that of PcSBn; 6 (λmax = 756.0 nm, log ε =
5.12). These results might suggest that since all the
phthalocyanines obtained have eight sulfur atoms
at the β-positions although the functional groups
linked to the sulfur atoms are different, such as the
SCHEME 2
2,3,9,10-tetrakis(benzylthio)bis(tetrathia-fulvaleno)
phthalocyanine (6-cis). It is expected that 6-trans
shows one singlet peak for the four methylthio
groups and one singlet peak for the four benzylthio
groups in the spectrum, whereas two singlet signals
in a 1:1 integral ratio for the four methylthio groups
and two singlet signals for the four benzylthio
groups appear in the spectrum of 6-cis. Compound
6 showed two broadened signals for the eight
methylene groups in a 1:1 integral ratio, and two
complex signals for the eight methyl groups in
the 1H NMR spectrum. In addition, two singlet
peaks with different heights were observed for
the four methylthio groups, in which one signal
could overlay two types of the methylthio groups,
suggesting that 6 contains two isomers 6-trans and
6-cis. These isomers cannot be separated by silica
gel and Bio-beads column chromatography.
When the 1H NMR of 7 was measured in
chloroform-d at 25◦C, broadened and unclear sig-
nals were observed in the spectrum. Measuring the
FIGURE 1 UV–vis spectra for phthalocyanine (5) titrated
with TFA (CHCl3).
Heteroatom Chemistry DOI 10.1002/hc

608 Kimura, Watanabe, and Namauo
TABLE 1 UV–vis Spectra and Redox Potentials of Phthalocyanines
E1/2(V)
Compound
UV–vis λ
(nm) (log ε)
Second Reduction
First Reduction
First Oxidation
Second Oxidation
max
5
755.0 (5.10)
756.0 (5.12)
757.0 (5.14)
755 (5.1)
–
−1.39
−1.30
−1.05
−1.31
–
−1.04
−1.03
−0.79
−1.02
–
0.41
0.38
0.38
0.49
0.55
1.36 (Ep)
0.77
0.73
0.72
0.96
6
7
PcSBn
3
UV–vis spectra were measured in CHCl3; redox potentials were measured in CH2Cl2 (vs. Ag/AgNO3).
TTF unit and the benzyl group, the π-electronic
system on the central phthalocyanine core is not
strongly affected by the difference of the outer func-
tional groups. The electronic effect of the TTF unit
on phthalocyanine through the sulfur atoms might
be similar to that of the benzyl group in the neutral
forms. On the other hand, it was reported that
splitting of the Q band absorption of metal-free ph-
thalocyanines decreases with increasing wavelength
of the absorption [4b]. Since the Q bands of 5, 6,
7, and PcSBn are shifted lower energy than that of
unsubstituted phthalocyanines, they should contain
several splitting absorption in their broadened
Q bands.
It has been previously reported that phthalo-
cyanines and related compounds can be protonated
FIGURE 2 Cyclic voltammogram of 7.
with acids to produce cationic species, which change
the absorption in the UV–vis spectra [16,17]. When
the UV–vis spectra of 5 (1.0 × 105 mol/L) were mea-
sured in the absence and presence of trifluoroacetic
acid (TFA) (0–200 equiv) to examine the effect of acid
concentration, the absorption in the spectra gradu-
ally changed (Fig. 1). Finally 5 was treated with 1
× 102 mol/L of TFA in chloroform, which generated
cationic species in the solution. The major absorp-
tion band at λmax = 755 nm gradually decreased in in-
tensity and resulted in a new band at λmax = 740 nm.
tion potentials (E1/2 = 0.38 and 0.77 V) and two
reversible reduction potentials (E1/2 = −1.03 and
−1.30 V). The first oxidation potentials of 5, 6, and
7 are lower than that of PcSBn. Compound 3 exhib-
ited two reversible oxidation potentials at E1/2 = 0.55
and 0.96 V.
CONCLUSION
3,6-Diethylphthalonitrile (3) was mixed with 1b in
the 1:1 ratio and treated with lithium in n-hexanol
to produce corresponding unsymmetrically substi-
tuted phthalocyanines 5, 6, and 7 with one through
three TTF units, respectively. The UV–vis spectra
of these products show similar absorption wave-
lengths, shapes, and molar extinction coefficients
to those of PcSBn, suggesting that the π-electronic
systems of these phthalocyanines are not strongly
affected by the outer functional groups at the β-
position under neutral conditions. The major ab-
sorption band of the cationic species of 5 generated
in chloroform/TFA shifted to shorter wavelengths by
ca. 15 nm from that of 5 measured in chloroform. It
is expected that the proton alternation on the central
Electrochemical Properties
To determine the electrochemical properties of 5,
6, and 7, their redox potentials were measured by
cyclic voltammetry using Ag/AgNO3 as a reference
electrode (solvent: CH2Cl2, scan rate: 200 mV/s).
As shown in Fig. 2, compound 7 showed two re-
versible oxidation potentials (E1/2 = 0.38 and 0.73
V) and two reversible reduction potentials (E1/2
=
−0.79 and −1.05 V). In the voltammogram of 5, one
reversible and one irreversible oxidation potential
(E1/2 = 0.41 V and Ep = 1.36 V) and two reversible
reduction potentials (E1/2 = −1.04 and −1.39 V) were
observed. Compound 6 shows two reversible oxida-
Heteroatom Chemistry DOI 10.1002/hc

Preparation and Optical and Electrochemical Properties of Octaethylphthalocyanines fused with TTF Units 609
four nitrogen atoms disappears by protonation with
Method B. A mixture of 1b (428.0 mg,
1.00 mmol) and AlCl3 (550 mg, 4.00 mmol) in toluene
(10 mL) was stirred at room temperature for 2 h
under Ar. To the solution, thiocarbonyldiimidazole
(360 mg, 2.00 mmol) was added and the solution was
stirred for 30 min. The reaction mixture was cooled
to 0◦C, and aqueous HCl solution was added after
evaporation of toluene. The product was extracted
with CH2Cl2, and purified with column chromatog-
raphy (n-hexane/CHCl3) to produce 2-S in 40% yield
(110 mg).
TFA in the solution, which changes the Q-band of 5.
The electrochemical properties of 5, 6, and 7 were
determined by cyclic voltammetry.
EXPERIMENTAL
General
NMR spectra were measured with Bruker AC-400
and Avance 500 spectrometers. The mass spectra
were obtained using a JEOL JMS-700 mass spec-
trometer. MALDI-TOF MS was examined with a
Bruker BIFLEX (III) mass spectrometer. UV–vis
spectra were measured with a JASCO Ubest-30 spec-
trometer. A Hokuto Denko Company model HAB-
151 apparatus was used to measure the redox poten-
tials. Bio-beads (S-X1) for column chromatography
were purchased from Nippon Bio-Rad Laboratories.
4,7-Diethyl-5,6-dicyanobenzo-1,3-dithiole-2-one
(2-O)
A mixture of 1a (350 mg, 1.00 mmol) and AlCl3 (568
mg, 4.3 mmol) in toluene (18 mL) was stirred at
room temperature for 2 h under Ar. To the solu-
tion, carbonyldiimidazole (407 mg, 2.5 mmol) was
added and the mixture was stirred at reflux tem-
perature for 1 h. The solution was cooled to room
temperature, and aqueous HCl solution was added.
The product was extracted with toluene and purified
with column chromatography (n-hexane/CHCl3) to
produce 2-O in 79% yield (215.2 mg): colorless crys-
Redox Potentials
All measurements were performed by cyclic voltam-
metry, using Ag/AgNO3 (0.01 mol/L) as a reference
electrode. A solution of 0.1 mol/L n-Bu4NClO4 in
CH2Cl2 was used as an electrolyte.
1
tals mp 171–171.5◦C; H NMR (400 MHz, CDCl3) δ
1.33 (t, J = 7.6 Hz, 6H, CH3), 2.96 (q, J = 7.6 Hz,
4H, CH2Ar); 13C NMR (101 MHz, CDCl3) δ 13.0, 29.3,
113.6, 114.0, 138.4, 141.5, 185.3; HRMS (EI): calcd.
for C13H10N2OS2, 274.0235; found, 274.0242 (M+).
Xylylenedithio-3,6-diethylphthalonitrile (1a)
and 4,5-Bis(benzylthio)-3,6-diethylphthalonitrile
(1b)
Compounds 1a and 1b were prepared from 1,4-
diethylbenzene by a method described previously
[6,7].
4,7-Diethyl-5,6-dicyano-2-(4ꢁ,5ꢁ-bis(methylthio)-
1ꢁ,3ꢁ-dithiole-2ꢁ-ylidene)benzo[d]-1,3-dithiole (3)
Method A. Compound 2-O (200 mg, 0.73
mmol) and 4,5-bis(methylthio)-1,3-dithiole-2-thione
(332 mg, 1.47 mmol) were dissolved in tri-
ethylphosphite (5 mL), and the mixture was stirred
at 120◦C for 4 h. The solution was cooled to
room temperature, and MeOH and brine were
added. The precipitate formed was filtered. The
residue was purified with column chromatogra-
phy (n-hexane/CHCl3) to produce 3 in 65% yield
(214.5 mg) together with 4,4ꢁ,7,7ꢁ-tetraethyl-5,5ꢁ,6,6ꢁ-
tetracyano-2,2ꢁ-bis(benzo-1,3-dithiole-2-ylidene) (4)
in 10% yield (33.5 mg); 3: red crystals; mp 224.5–
225.5◦C; 1H NMR (400 MHz, CDCl3) δ 1.29 (t,
J = 7.6 Hz, 6H, CH3), 2.45 (s, 6H, SCH3), 2.82 (q,
J = 7.6 Hz, 4H, CH2Ar); 13C NMR (101 MHz, CDCl3)
δ 12.7, 19.2, 28.9, 105.8, 113.3, 114.5, 115.4, 127.6,
139.6, 143.6; HRMS (EI): calcd. for C18H16N2S6,
451.9638; found, 451.9643 (M+); 4: yellow powder;
mp. >300◦C; 1H NMR (400 MHz, CDCl3) δ 1.31
(t, J = 7.6 Hz, 12H, CH3), 2.85 (q, J = 7.6 Hz, 8H,
4,7-Diethyl-5,6-dicyanobenzo-1,3-dithiole-2-
thione (2-S)
Method A. A mixture of 1a (365.3.0 mg, 1.04
mmol) and AlCl3 (570 mg, 4.3 mmol) in toluene
(10 mL) was stirred at room temperature for 2 h
under Ar. To the solution, thiocarbonyldiimidazole
(454 mg, 2.55 mmol) was added and the mixture
was stirred at reflux temperature for 1 h. The solu-
tion was cooled to room temperature, and aqueous
HCl solution was added. The product was extracted
with toluene and purified with column chromatog-
raphy (n-hexane/CHCl3) to produce 2-S in 61% yield
(185.1 mg): yellow crystals; mp 150–151◦C; 1H NMR
(400 MHz, CDCl3) δ 1.34 (t, J = 7.6 Hz, 6H, CH3),
2.92 (q, J = 7.6 Hz, 4H, CH2Ar); 13C NMR (101 MHz,
CDCl3) δ 13.1, 28.7, 113.9, 114.2, 140.4, 145.8, 206.9;
HRMS (EI): calcd. for C13H10N2S3, 290.0006; found,
290.0002 (M+).
Heteroatom Chemistry DOI 10.1002/hc

610 Kimura, Watanabe, and Namauo
CH2Ar); HRMS (EI): calcd. for C26H20N4S4, 516.0571;
found, 516.0575 (M+).
(s, 12H, SCH3), 4.23–4.33 (m, 8H, CH2Ar), 4.45(9)
and 4.46(4) (s, 8H, SCH2Ar), 4.57–4.70 (m, 8H,
CH2Ar), 7,13–7.19 (m, 4H, Ar), 7.19–7.24 (m, 8H,
Ar), 7.29–7.37 (m, 8H, Ar); UV–vis (CHCl3) λmax
nm (log ε) 756 (5.12); MALDI-TOF-MS m/z 1766.44
(M+); 7: dark green powder; mp. 110–111◦C; 1H
NMR (400 MHz, CDCl3) δ 1.54 (t, J = 7.4 Hz, 6H,
CH3), 1.58–1.76 (m, 18H, CH3), 2.50 (s, 18H, SCH3),
4.15–4.36 (m, 12H, CH2Ar), 4.47 (s, 4H, SCH2Ar),
4.62–4.78 (m, 4H, CH2Ar), 7,11–7.37 (m, 10H, Ar);
UV–vis (CHCl3) λmax nm (log ε) 757 (5.14); FABMS
m/z 1788.1 (MH+).
Method B. Compound 2-S (200 mg, 0.73 mmol)
and 4,5-bis(methylthio)-1,3-dithiole-2-one (332 mg,
1.47 mmol) were dissolved in triethylphosphite
(5 mL), and the mixture was stirred at 120◦C
for 4 h. The solution was cooled to room tem-
perature, and MeOH and brine were added.
The precipitate formed was filtered. The residue
was purified with column chromatography (n-
hexane/CHCl3) to produce 3 in 28% yield (77.4 mg)
together with 4,4ꢁ,7,7ꢁ-tetraethyl-5,5ꢁ,6,6ꢁ-tetracyano-
2,2ꢁ-bis(benzo-1,3-dithiole-2-ylidene) (4) in 11%
yield (29.8 mg).
REFERENCES
[1] (a) Kadish, K. M.; Smith, K. M.; Guilard, R. The
Porphyrin Handbook—; Academic Press: San Diego,
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Preparation of 1,4,8,11,15,18,22,25-Octaethyl-2,
3,9,10,16,17-hexakis(benzylthio)-23,24-[4ꢁ,5ꢁ-bis
(methylthio)tetrathiafulvaleno]phthalocyanine
(5), Octaethyltetrakis(benzylthio)bis[4ꢁ,5ꢁ-bis
(methylthio)tetrathiafulvaleno]phthalocyanine
(6), and 1,4,8,11,15,18,22,25-Octaethyl-23,
24-bis(benzylthio)-2,3,9,10,16,17-tris[4ꢁ,5ꢁ-bis
(methylthio)tetrathiafulvaleno]-phthalocyanine
(7)
Lithium (36 mg, 5.2 mmol) was placed in a glass
reactor, and n-hexanol (1.5 mL) was added under
Ar. The solution was stirred at 120◦C for several
minutes. A mixture of 3 (117 mg, 0.26 mmol) and
1a (111 mg, 0.26 mmol) was added, and the solution
was stirred at 120◦C for 3 h. After cooling to room
temperature, a MeOH solution of HCl was added and
the resulting blue-green precipitate was filtered. The
residue was purified by column chromatography
(Wakogel C-400HG, n-hexane/CHCl3) to produce
5 in 2% yield (7.9 mg) together with 6 (9.5 mg,
4%) and 7 (11.2 mg, 7%). It should be noted that 6
may be a mixture of 1,4,8,11,15,18,22,25-octaethyl-
16,17,23,24-tetrakis(benzylthio)-2,3,9,10-bis[4ꢁ,5ꢁ -
bis(methylthio)tetrathiafulvaleno]-phthalocyanine
(6-cis) and 1,4,8,11,15,18,22,25-octaethyl-9,10,23,
24-tetrakis(benzylthio)-2,3,16,17-bis[4ꢁ,5ꢁ-bis(meth-
ylthio)tetrathiafulvaleno]phthalocyanine (6-trans).
However, these isomers could not be isolated from
each other; 5: dark green powder; mp 105–105.5◦C;
1H NMR (400 MHz, CDCl3) δ1.42–1.60 (m, 18H,
CH3), 1.64 (t, J = 7.4 Hz, 6H, CH3), 2.46 (s, 6H,
SCH3), 4.24–4.32 (m, 4H, CH2Ar), 4.45 (s, 12H,
SCH2Ar), 4.53–4.71 (m, 12H, CH2Ar), 7,12–7.17
(m, 6H, Ar), 7.17–7.24 (m, 12H, Ar), 7.29–7.36 (m,
12H, Ar); UV–vis (CHCl3) λmax nm (log ε) 755 (5.10);
MALDI-TOF-MS m/z 1740.59 (M+); 6: dark green
powder; mp. 107–107.5◦C; 1H NMR (400 MHz,
CDCl3) δ 1.44–1.72 (m, 24H, CH3), 2.47 and 2.48
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