A direct comparison of the aggregation behavior of phthalocyanines and 2,3-naphthalocyanines

Article abstract of DOI:10.1016/S0040-4020(00)00326-4

Two pairs of analogous zinc(II) phthalocyanines and 2,3- naphthalocyanines with eight butylthio or 3,6-dioxa-1-decylthio substituents have been synthesized and shown to exhibit a substantial aggregation tendency in organic solvents. The visible spectra of the octakis(3,6-dioxa-1- decylthio) naphthalocyanine 7 have been recorded in THF with different concentrations and the data have been analyzed using a nonlinear least- squares fitting procedure giving ε(m) (777 nm), ε(d) (777 nm), and K(d) at 1.95 x 10⁶ M^-1 cm^-1, 1.29 x 10⁵ M^-1 cm^-1, and 2.72 x 10⁵ M^-1, respectively. Simulated visible spectra for the pure monomeric and dimeric 7 have also been obtained. By variable-concentration and variable-temperature visible spectroscopic studies, the heats of aggregation of all these in toluene have also been determined (-17.1 to -105.0 kJ mol^-1). These values depend-largely on the additional interactions due to the substituents. (C) 2000 Elsevier Science Ltd.

Full text of DOI:10.1016/S0040-4020(00)00326-4

TETRAHEDRON
Pergamon
Tetrahedron 56 (2000) 3881±3887
A Direct Comparison of the Aggregation Behavior of
Phthalocyanines and 2,3-Naphthalocyanines
*
Michael T. M. Choi, Pearl P. S. Li and Dennis K. P. Ng
Department of Chemistry, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, People's Republic of China
Received 2 February 2000; revised 28 March 2000; accepted 13 April 2000
AbstractÐTwo pairs of analogous zinc(II) phthalocyanines and 2,3-naphthalocyanines with eight butylthio or 3,6-dioxa-1-decylthio
substituents have been synthesized and shown to exhibit a substantial aggregation tendency in organic solvents. The visible spectra of
the octakis(3,6-dioxa-1-decylthio) naphthalocyanine 7 have been recorded in THF with different concentrations and the data have been
analyzed using a nonlinear least-squares ®tting procedure giving em (777 nm), ed (777 nm), and Kd at 1.95£106 M21 cm21, 1.29£
105 M21 cm21, and 2.72£105 M21, respectively. Simulated visible spectra for the pure monomeric and dimeric 7 have also been obtained.
By variable-concentration and variable-temperature visible spectroscopic studies, the heats of aggregation of all these macrocycles in toluene
have also been determined (217.1 to 2105.0 kJ mol21). These values depend largely on the additional interactions due to the substituents.
q 2000 Elsevier Science Ltd. All rights reserved.
Introduction
entry to allow a more detailed examination of the character-
istics of these larger macrocyclic p system and a
comparison with those of their phthalocyanine analogues.
Phthalocyanines are one of the major types of tetrapyrrole
derivative showing a wide range of applications in materials
science, medicine, and catalysis.1 Owing to the extended p
system, it is well-known that these macrocyclic compounds
exhibit a high aggregation tendency forming dimeric and
oligomeric species in solutions.2 It has been shown that
this molecular association greatly in¯uences the intrinsic
nature of the macrocycles including their spectroscopic,2,3
photophysical,4 electrochemical,5 and conducting proper-
ties,6 and eventually their performance as superior molecu-
lar materials. The strong intermolecular interactions also
hinder the puri®cation and characterization processes.
Phthalocyanines that are not substituted appropriately
have a poor mobility in silica gel and alumina columns
and puri®cation can only be performed by the less ef®cient
Soxhlet extraction procedure and re-precipitation.
This paper reports the preparation of two pairs of phthalo-
cyanines and 2,3-naphthalocyanines containing alkylthio or
dioxaalkylthio side chains. The aggregation behavior of
these compounds, as probed by variable-concentration and
temperature UV±Vis spectroscopy, is discussed and
compared.
Results and Discussion
The naphthalocyanines 6 and 7 were prepared by the
method reported by us9c,d and Kitahara et al.,10 which
involves the aromatic nucleophilic substitution of dibromo-
naphthalene 1 with the corresponding thiolate ions,
followed by
a
typical base-promoted cyclization
A substantial number of investigations have been focused
on the aggregation behavior of substituted phthalocyanines
in various solvent systems in which the aggregation number
and some thermodynamic parameters have been deter-
mined.2,7 Being larger p systems, 2,3-naphthalocyanines
are expected to have an even higher aggregation tendency.
Studies in this area, however, have been extremely rare.8 As
synthetic routes to differently substituted 2,3-naphthalo-
cyanines have been recently developed,9 these open up an
(Scheme 1). The ®rst step of these reactions is promoted
by copper(I) oxide, which increases the yield of the
dinitriles 4 and 5 from ca. 30 to 70%. Two types of sub-
stituents, namely butylthio (SC4H9) and 3,6-dioxa-1-
decylthio [S(CH2CH2O)2C4H9] groups, which have very
different chain length and polarity were selected. To
compare directly the aggregation behavior of naphthalo-
cyanines and phthalocyanines, the phthalocyanine
analogues with identical substituents were also prepared
by similar methodology. Thus treatment of dichlorobenzene
8 with thiols 2 and 3, in the presence of sodium hydride and
copper(I) oxide, afforded the dinitriles 9 and 10, respec-
tively, which underwent cyclization to give the respective
phthalocyanines 11 and 12 (Scheme 2). The former
Keywords: aggregation; phthalocyanine; naphthalocyanine; electronic
spectra.
* Corresponding author. Tel.: 1852-2609-6375; fax: 1852-2603-5057;
e-mail: dkpn@cuhk.edu.hk
0040±4020/00/$ - see front matter q 2000 Elsevier Science Ltd. All rights reserved.
PII: S0040-4020(00)00326-4

3882
M. T. M. Choi et al. / Tetrahedron 56 (2000) 3881±3887
Scheme 1.
macrocycle was synthesized previously by metallation of
the metal-free analogue which was prepared from 1,2-
dibutylthiobenzene using a different synthetic route.11
1H NMR spectra of the naphthalocyanines 6 and 7 were
recorded in CDCl3 and showed only broad signals for the
substituents while the aromatic protons' signals were not
observed. However, in the presence of pyridine-d5, the latter
emerged as two relatively broad bands at d 8.87±9.00 and
7.85±8.04, which could be assigned to the Ha and Hb
protons, respectively, and the aliphatic protons' signals
were better resolved. This observation suggests that the
p±p interactions of these macrocycles are signi®cant in
chloroform and can be partially disrupted by pyridine as
described previously.9d,13 The phthalocyanine analogues
11 and 12 have similar spectral properties. The down®eld
aromatic proton signal was clearly seen at d 9.28 [for 11
(7.8 mM)] or d 9.61 [for 12 (1.5 mM)] in pyridine-d5. As the
latter signal was much broader than the former, even though
it was recorded at a lower concentration, compound 12
seems to be more strongly aggregated than the thiobutyl
counterpart 11.
Due to the eight peripheral substituents, all macrocycles
possessed good solubility in common organic solvents and
could be puri®ed by column chromatography using THF as
a co-eluent, which breaks up the molecular aggregation and
increases the mobility of these compounds on silica gel
columns.9d All new compounds were characterized using
various spectroscopic methods and elemental analyses.12
The UV±Vis spectra of all these macrocycles in THF
displayed a typical B band (354±366 nm) and Q band
(775±778 nm for 6 and 7, 701±709 nm for 11 and 12),
along with up to two vibronic bands near the latter. Due
to the extended conjugation, the Q band of the naphthalo-
cyanines 6 and 7 was red-shifted by ca. 70 nm compared
with that of the phthalocyanine analogues. As the effects of
aggregation on the spectral properties of phthalocyanines
have been well-documented,2±4 special emphasis was
placed on the naphthalocyanine system. Fig. 1 shows the
changes in the visible spectrum of 7 in THF with concentra-
tion. It can be seen that the molar absorptivity of the Q band
increases from 9.8£105 to 2.2£106 M21 cm21 as the concen-
tration decreases from 4.20£1026 to 7.31£1028 M which
can be attributed to the effect of aggregation. In contrast
with the phthalocyanine system in which the Q band due
to the aggregated (mainly dimeric) species is normally blue-
shifted by ca. 30 nm compared with that of the monomeric
Scheme 2.

M. T. M. Choi et al. / Tetrahedron 56 (2000) 3881±3887
3883
Figure 1. Concentration dependence of visible spectrum of 7 in THF.
species, the Q band of 7 remains essentially unshifted as
monomer and dimer, respectively, at a given wavelength,
with ed expressed in terms of the monomer, and [m] and [d]
being concentrations (M) of monomer and dimer, respec-
tively. The dimerization constant (Kd) and the total concen-
tration [Ct] can be expressed as:
observed previously in other naphthalocyanines.8,9c
These spectral data were analyzed using a nonlinear least-
squares ®tting method, which assumes that no higher aggre-
gates than dimers are formed.14 According to some previous
studies,2a,7a,14,15 this assumption is normally valid, in par-
ticular in such dilute solutions. In this case, the observed
absorbance, A, of a solution in a 1-cm cell can be written as:
2
Kd ˆ ‰dŠ=‰mŠ
ꢀ2†
ꢀ3†
‰CtŠ ˆ ‰mŠ 1 2‰dŠ
Eqs. (1)±(3) can be combined and rearranged to give:
A ˆ em‰mŠ 1 2ed‰dŠ
ꢀ1†
p
where em and ed are molar absorptivities (M21 cm21) of
A ˆ ed‰CtŠ 1 ꢀem 2 ed†‰21 1 ꢀ1 1 8Kd‰CtŠ†Š=4Kd
ꢀ4†
Figure 2. Plots of experimental (V) and calculated (B) absorbances vs. the concentration of 7 in THF. The inset shows an expansion of the lower-concentration
region.

3884
M. T. M. Choi et al. / Tetrahedron 56 (2000) 3881±3887
Figure 3. Simulated visible spectra for pure monomeric (V) and dimeric (B) 7 in THF.
in which A and [Ct] are measurable quantities and the three
variables em, ed and Kd can be determined by a nonlinear
least-squares ®tting procedure using a series of absorbances
at a given wavelength measured at different concentrations.
By recording the visible spectra of 7 in THF at concentra-
tions ranging from 7.31£1028 to 4.20£1026 M and using the
observed absorbance at the Q band (777 nm), the best-®tted
values of em (777 nm), ed (777 nm), and Kd were deter-
observed values and the aggregation causes a deviation
from the Beer±Lambert law. The former two e values are
higher than the corresponding values for phthalocyanines by
ca. one order of magnitude,2b,14 while the dimerization
constant falls into the region (104±106 M21) which is typical
for other phthalocyanines and naphthalocyanines in various
solvent systems.2b,8,14,15
mined to be 1.95£106 M21 cm21, 1.29£105 M21 cm21
,
By repeating this procedure at different wavelengths (from
650 to 820 nm) with a ®xed value of Kd (2.72£105 M21), a
series of (em, ed) values were obtained which could be used
and 2.72£105 M21, respectively. As shown in Fig. 2, the
calculated values of absorbance are very close to the
Figure 4. Variation of molar absorptivity at 775 nm for 7 in toluene with concentration and temperature.

M. T. M. Choi et al. / Tetrahedron 56 (2000) 3881±3887
3885
compounds were also determined to be 226.4, 217.1, and
2105.0 kJ mol21, respectively. It is clear that the sub-
stituents greatly affect the aggregation tendency of these
p systems. With nonpolar butylthio substituents, the
naphthalocyanine system appears to be slightly more aggre-
gated and releases more thermal energy as the molecules
associate. This is expected due to the larger p system of
naphthalocyanines. The value is comparable with those of
tetrasulfonated phthalocyanines in water.17 But with longer
and more polar 3,6-dioxa-1-decylthio groups, a reversed
order is observed showing that the dipole±dipole inter-
actions associated with the side chains play a crucial role.
It seems that the macrocycle 12, under the in¯uence of the
substituents, has a better molecular contact than the
naphthalocyanine analogue 7. The results are in accord
with the NMR data as described above. It is worth noting
that the DHa value of 12 is comparable with that of the
metal-free phthalocyanine prepared by Nolte et al.,7b
which contains four fused benzo 18-crown-6 moieties
(2125 kJ mol21). As 12 does not contain peripheral
benzene rings, the extraordinary high DHa value of the
Nolte's phthalocyanine may not be due to the additional
p±p interactions arising from the peripheral benzene
rings as suggested by the authors, but rather may arise
from the interactions due to the oligo(oxyethylene) units.
Figure 5. Plot of ln c vs. 1/T£103 for 7 in toluene.
to simulate the visible spectra of pure monomeric 7 and
dimeric 7 in THF (Fig. 3). It can be seen that the monomeric
spectrum shows a typical and very intense Q band and two
well-resolved vibronic bands, while the dimeric spectrum
exhibits three relatively weak bands at 720, 755 and 790 nm.
This spectrum resembles the simulated dimeric spectra of
the tetrahalophthalocyanine analogues,14b which also
display three absorption bands from ca. 620±700 nm but
with lower absorptivities. As the differences in absorp-
tivities between the monomeric and dimeric species are
much larger in the naphthalocyanine system than in the
phthalocyanine counterpart, this may explain why the Q
band of naphthalocyanines remains essentially unshifted
even in the presence of a signi®cant amount of dimeric
species.
In summary, we have prepared two pairs of phthalocyanine
and naphthalocyanine analogues for a direct comparison of
their aggregation behavior. Both classes of tetrapyrrole
derivatives show a substantial aggregation tendency in solu-
tion and the degree of association depends largely on the
additional interactions due to the substituents.
Experimental
The visible spectra of these macrocycles were found to be
not only concentration dependent but also temperature
dependent. Fig. 4 shows the variation of the molar absorp-
tivity at 775 nm (the apparent Q band maximum) for 7 in
toluene with concentration and temperature. It can be seen
that a higher temperature, similar to the effect of lower
concentration, can also reduce the extent of aggregation
leading to a higher absorptivity. At a ®xed value of eobs
which can be achieved by changing the concentration and
temperature of the solutions, the weight fraction of the
monomer is constant and the following relationship
holds:7b,16
General
Reactions were performed under an atmosphere of nitrogen.
THF was distilled from sodium benzophenone ketyl. Butan-
1-ol and hexan-1-ol were distilled from sodium prior to use.
N,N-Dimethylformamide (DMF) was pre-dried over barium
oxide and distilled under reduced pressure. Chromatographic
puri®cations were performed on silica gel columns (Merck,
Kieselgel 60, 70±230 mesh) with the indicated eluents. The
hexane used in chromatography was distilled from anhy-
drous CaCl2. All other reagents and solvents were of reagent
grade and used as received. 2,3-Dibromo-6,7-dicyano-
naphthalene (1)18 and 1,2-dichloro-4,5-dicyanobenzene
(8)19 were prepared according to literature procedures.
DHa ˆ R D ln c=Dꢀ1=T†
ꢀ5†
where DHa is the heat of association, R is the gas constant, c
and T are the concentration and temperature, respectively.
Based on the data in Fig. 4, there are six pairs of (c, T )
values at an arbitrary value of eobs which can be used to
generate a plot of ln c vs. 1/T. As shown in Fig. 5, a best-
®tted straight line is obtained from which the DHa value for
7 in toluene can be estimated to be 238.4 kJ mol21. Since
the spectral features were more susceptible to concentration
than to temperature, a rather narrow concentration range had
to be maintained; otherwise, the spectral changes could not
be restored within attainable temperatures. The other three
macrocycles 6, 11 and 12 behaved similarly and by using a
similar treatment, the heats of association for these
1
Melting points are uncorrected. H and 13C NMR spectra
were recorded on a Bruker DPX 300 spectrometer (1H, 300;
13C, 75.4 MHz) or a Bruker ARX 500 spectrometer (1H,
500 MHz) with SiMe4 as an internal reference. IR spectra
were measured on a Nicolet Magna 550 FT-IR spectrometer
as KBr pellets. UV±Vis spectra were taken on a Hitachi
U-3300 spectrophotometer equipped with a temperature
controller. Electron impact (EI) and liquid secondary-ion
(LSI) mass spectra were recorded on a Hewlett±Packard
5989B mass spectrometer and Bruker APEX 47e Fourier
transform ion cyclotron resonance (FTICR) mass spectro-
meter, respectively. The latter employed 3-nitrobenzyl

3886
M. T. M. Choi et al. / Tetrahedron 56 (2000) 3881±3887
alcohol as the matrix. Elemental analyses were performed
by the Shanghai Institute of Organic Chemistry, Chinese
Academy of Sciences.
1,2-Dicyano-4,5-bis(3,6-dioxa-1-decylthio)benzene (10).
By using compound 8 (0.39 g, 2.0 mmol) and 3,6-dioxa-1-
decanethiol (3) (0.75 g, 4.2 mmol) as the starting materials
and following the general procedure, compound 10 was
obtained as a white solid after being puri®ed by chromato-
graphy with hexane/ethyl acetate (9:1) as eluent. Yield:
General procedure for the preparation of dinitriles
1
0.87 g (90%), mp 40±418C. H NMR (CDCl3, 300 MHz):
1-Butanethiol (2) or 3,6-dioxa-1-decanethiol (3) (2.1 equiv.)
was added slowly to an ice-cooled suspension of NaH (60%
dispersion in mineral oil, 2.5 equiv.) in DMF. The mixture
was stirred for a few minutes until the evolution of hydrogen
gas was complete. 2,3-Dibromo-6,7-dicyanonaphthalene (1)
or 1,2-dichloro-4,5-dicyanobenzene (8) (1.0 equiv.) and
copper(I) oxide (2.0 equiv.) were then added and the
mixture was re¯uxed for 3 h. The cooled mixture was
poured into ice then extracted with diethyl ether. The
combined organic portions were washed with ammonia
solution (35%) and water, then dried over anhydrous
CaCl2. The volatiles were removed by rotary evaporation
and the residue was puri®ed by column chromatography.
d 7.63 (s, 2H, ArH), 3.80 (t, Jˆ7.5 Hz, 4H, OCH2), 3.63±
3.66 (m, 4H, OCH2), 3.56±3.59 (m, 4H, OCH2), 3.46 (t,
Jˆ7.5 Hz, 4H, OCH2), 3.24 (t, Jˆ7.5 Hz, 4H, SCH2), 1.57
(quintet, Jˆ7.5 Hz, 4H, CH2), 1.35 (sextet, Jˆ7.5 Hz, 4H,
CH2), 0.92 (t, Jˆ7.5 Hz, 6H, CH3). 13C{1H} NMR (CDCl3,
75.4 MHz): d 144.0, 129.4, 115.5, 111.5, 71.3, 70.8, 70.0,
69.3, 32.7, 31.7, 19.2, 13.9. MS (EI): m/z 480 (M1). Anal.
Calcd for C24H36N2O4S2: C, 59.97; H, 7.55; N, 5.83. Found:
C, 59.45; H, 7.88; N, 5.35.
General procedure for the cyclization of dinitriles
A mixture of dinitrile (2.6 equiv.) and Zn(OAc)2´2H2O
(1.0 equiv.) in butan-1-ol or hexan-1-ol was heated to
908C, then 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) (ca.
0.5 mL) was added and the mixture was stirred at 1408C for
3 h. The mixture was cooled then added dropwise to a
mixture of methanol/water (1:1). The precipitate formed
was ®ltered and washed with water, acetone and methanol
successively. The crude product was then puri®ed by
chromatography giving a green solid.
2,3-Dibutylthio-6,7-dicyanonaphthalene (4). According
to the general procedure, compound 1 (0.68 g, 2.0 mmol)
was treated with 1-butanethiol (2) (0.45 mL, 4.2 mmol) in
DMF (50 mL) to give 4, which was puri®ed by chromato-
graphy with CHCl3 as eluent. A yellow solid was obtained.
1
Yield: 0.46 g (65%), mp 148±1508C. H NMR (CDCl3,
300 MHz): d 8.16 (s, 2H, ArH), 7.58 (s, 2H, ArH), 3.09
(t, Jˆ7.5 Hz, 4H, SCH2), 1.79 (quintet, Jˆ7.5 Hz, 4H,
CH2), 1.55 (sextet, Jˆ7.5 Hz, 4H, CH2), 0.99 (t,
Jˆ7.5 Hz, 6H, CH3). 13C{1H} NMR (CDCl3, 75.4 MHz):
d 142.7, 134.1, 130.8, 123.0, 116.1, 109.3, 32.6, 30.1,
22.2, 13.6. MS (EI): m/z 354 (M1). Anal. Calcd for
C20H22N2S2: C, 67.76; H, 6.25; N, 7.90. Found: C, 67.70;
H, 6.24; N, 7.76.
(3,4,12,13,21,22,30,31-Octabutylthio-2,3-naphthalo-
cyaninato)zinc(II) (6). According to the general procedure,
dinitrile 4 (354 mg, 1.0 mmol) was treated with Zn-
(OAc)2´2H2O (82 mg, 0.37 mmol) in butan-1-ol (5 mL) to
give 6, which was puri®ed by chromatography with toluene/
THF (7:3) as eluent. Yield: 236 mg (64%). 1H NMR
[CDCl3/pyridine-d5 (7:3), 300 MHz]: d 8.87 (br. s, 8H,
ArH), 7.85 (br. s, 8H, ArH), 3.04±3.16 (m, 16H, SCH2),
1.70±1.90 (m, 16H, CH2), 1.45±1.65 (m, 16H, CH2), 0.96
(t, Jˆ7.5 Hz, 24H, CH3). UV±Vis (THF, lmax nm): 355,
693, 745, 778. MS (LSI): an isotopic cluster peaking at
m/z 1482.33 (Calcd for M1 1482.42).
2,3-Dicyano-6,7-bis(3,6-dioxa-1-decylthio)naphthalene
(5). By using compound 1 (0.34 g, 1.0 mmol) and 3,6-dioxa-
1-decanethiol (3) (0.37 g, 2.1 mmol) as the starting
materials and following the general procedure, compound
5 was obtained as a yellow solid after being puri®ed by
chromatography with hexane/ethyl acetate (3:2) as eluent.
Yield: 0.38 g (72%), mp 45±478C. 1H NMR (CDCl3,
300 MHz): d 8.18 (s, 2H, ArH), 7.77 (s, 2H, ArH), 3.82
(t, Jˆ7.5 Hz, 4H, OCH2), 3.65±3.68 (m, 4H, OCH2),
3.57±3.60 (m, 4H, OCH2), 3.46 (t, Jˆ7.5 Hz, 4H, OCH2),
3.31 (t, Jˆ7.5 Hz, 4H, SCH2), 1.56 (quintet, Jˆ7.5 Hz, 4H,
CH2), 1.35 (sextet, Jˆ7.5 Hz, 4H, CH2), 0.91 (t, Jˆ7.5 Hz,
6H, CH3). 13C{1H} NMR (CDCl3, 75.4 MHz): d 142.1,
134.2, 131.1, 124.4, 115.9, 109.5, 71.3, 70.7, 70.0, 69.2,
32.7, 31.6, 19.2, 13.9. MS (EI): m/z 530 (M1). Anal.
Calcd for C28H38N2O4S2: C, 63.37; H, 7.22; N, 5.28; S,
12.08. Found: C, 63.64; H, 7.24; N, 5.49; S, 12.38.
[3,4,12,13,21,22,30,31-Octakis(3,6-dioxa-1-decylthio)-
2,3-naphthalocyaninato]zinc(II) (7). By using the general
procedure, dinitrile 5 (200 mg, 0.38 mmol) was treated with
Zn(OAc)2´2H2O (30 mg, 0.14 mmol) in hexan-1-ol (10 mL)
to give 7, which was puri®ed by chromatography with tolu-
1
ene/THF (1:1) as eluent. Yield: 93 mg (45%). H NMR
[CDCl3/pyridine-d5 (7:3), 300 MHz]: d 9.00 (br. s, 8H,
ArH), 8.04 (br. s, 8H, ArH), 3.90 (t, Jˆ7.5 Hz, 16H,
OCH2), 3.67±3.69 (m, 16H, OCH2), 3.58±3.60 (m, 16H,
OCH2), 3.34±3.45 (m, 32H, OCH2 and SCH2), 1.51
(quintet, Jˆ7.5 Hz, 16H, CH2), 1.28 (sextet, Jˆ7.5 Hz,
16H, CH2), 0.79 (t, Jˆ7.5 Hz, 24H, CH3). 13C{1H} NMR
[CDCl3/pyridine-d5 (7:3), 75.4 MHz]: d 152.0, 135.5,
134.7, 131.4, 128.0, 120.0, 71.0, 70.4, 69.9, 69.4, 32.9,
31.5, 19.0, 13.7. UV±Vis (THF, lmax nm): 354, 702, 740,
777. MS (LSI): an isotopic cluster peaking at m/z 2186.7
(Calcd for M1 2186.8). Anal. Calcd for C112H152N8O16S8Zn:
C, 61.47; H, 7.00; N, 5.12; S, 11.72. Found: C, 60.88; H,
7.35; N, 4.77; S, 10.82.
1,2-Dibutylthio-4,5-dicyanobenzene (9). By using the
general procedure, compound 8 (0.79 g, 4.0 mmol) was
treated with 1-butanethiol (2) (0.9 mL, 8.4 mmol) in DMF
(50 mL) to give 9. The crude product was puri®ed by chro-
matography with CHCl3 as eluent to yield a white solid.
Yield: 1.13 g (93%), mp 109±1118C (lit.11 mp 110±
1128C). 13C{1H} NMR (CDCl3, 75.4 MHz): d 144.2,
128.1, 115.7, 111.0, 32.4, 30.0, 22.0, 13.6. MS (EI): m/z
304 (M1).

M. T. M. Choi et al. / Tetrahedron 56 (2000) 3881±3887
3887
Phillips, D. J. Photochem. Photobiol. A: Chem. 1996, 100, 77.
(c) Howe, L.; Zhang, J. Z. J. Phys. Chem. A 1997, 101, 3207.
(2,3,9,10,16,17,23,24-Octabutylthiophthalocyaninato)-
zinc(II) (11).11 According to the general procedure, dinitrile
9 (0.61 g, 2.0 mmol) was treated with Zn(OAc)2´2H2O
(0.16 g, 0.73 mmol) in butan-1-ol (10 mL) to give 11,
which was puri®ed by chromatography with toluene/THF
(4:1) as eluent. Yield: 0.47 g (73%). 1H NMR [pyridine-d5,
300 MHz]: d 9.28 (s, 8H, ArH), 3.60 (t, Jˆ7.5 Hz, 16H,
SCH2), 2.06 (quintet, Jˆ7.5 Hz, 16H, CH2), 1.76 (sextet,
Jˆ7.5 Hz, 16H, CH2), 1.11 (t, Jˆ7.5 Hz, 24H, CH3).
13C{1H} NMR [CDCl3/pyridine-d5 (7:3), 75.4 MHz]: d
151.4, 138.3, 134.9, 119.9, 33.1, 30.6, 22.1, 13.5. MS
(LSI): an isotopic cluster peaking at m/z 1282.29 (Calcd
for M1 1282.35). Anal. Calcd for C64H80N8S8Zn: C,
59.90; H, 6.28; N, 8.73. Found: C, 58.92; H, 6.33; N, 8.26.
Â
Â
(d) Lang, K.; Kubat, P.; Mosinger, J.; Wagnerova, D. M. J.
Photochem. Photobiol. A: Chem. 1998, 119, 47. (e) Ng, A. C. H.;
Li, X.-Y.; Ng, D. K. P. Macromolecules 1999, 32, 5292.
Â
5. (a) Louati, A.; El Meray, M.; Andre, J. J.; Simon, J.; Kadish,
K. M.; Gross, M.; Giraudeau, A. Inorg. Chem. 1985, 24, 1175.
(b) Isago, H.; Leznoff, C. C.; Ryan, M. F.; Metcalfe, R. A.; Davids,
R.; Lever, A. B. P. Bull. Chem. Soc. Jpn. 1998, 71, 1039.
6. (a) Law, K.-Y. J. Phys. Chem. 1988, 92, 4226. (b) Deng, H.;
Mao, H.; Lu, Z.; Xu, H. Thin Solid Films 1998, 315, 244.
7. See for example: (a) Schelly, Z. A.; Harward, D. J.; Hemmes,
P.; Eyring, E. M. J. Phys. Chem. 1970, 74, 3040. (b) van Nostrum,
C. F.; Picken, S. J.; Schouten, A.-J.; Nolte, R. J. M. J. Am. Chem.
Soc. 1995, 117, 9957. (c) Zhou, J.; Wang, Y.; Qiu, J.; Cai, L.; Ren,
D.; Di, Z. Chem. Commun. 1996, 2555. (d) Amaral, C. L. C.; Politi,
M. J. Langmuir 1997, 13, 4219.
[2,3,9,10,16,17,23,24-Octakis(3,6-dioxa-1-decylthio)-
phthalocyaninato]zinc(II) (12). According to the general
procedure, dinitrile 10 (0.86 g, 1.79 mmol) was treated with
Zn(OAc)2´2H2O (0.14 g, 0.64 mmol) in hexan-1-ol (25 mL)
to give 12, which was puri®ed by chromatography with
toluene/THF (1:1) as eluent. Yield: 0.18 g (20%). 1H
NMR (pyridine-d5, 500 MHz): d 9.61 (br. s, 8H, ArH),
4.24±4.25 (m, 16H, OCH2), 3.89±3.93 (m, 16H, OCH2),
3.77±3.82 (m, 32H, OCH2), 3.53 (t, Jˆ6.3 Hz, 16H,
SCH2), 1.61 (quintet, Jˆ7.0 Hz, 16H, CH2), 1.40 (sextet,
Jˆ7.4 Hz, 16H, CH2), 0.84 (t, Jˆ7.4 Hz, 24H, CH3). UV±
Vis (THF, lmax nm): 366, 632, 701. MS (LSI): an isotopic
cluster peaking at m/z 1986.7 (Calcd for M1 1986.8). Anal.
Calcd for C96H144N8O16S8Zn: C, 58.00; H, 7.30; N, 5.64.
Found: C, 57.01; H, 7.37; N, 5.33.
8. Tai, S.; Hayashi, N. J. Chem. Soc., Perkin Trans. 2 1991, 1275.
9. (a) Polley, R.; Hanack, M. J. Org. Chem. 1995, 60, 8278.
(b) Cammidge, A. N.; Chambrier, I.; Cook, M. J.; Garland, A. D.;
Heeney, M. J.; Welford, K. J. Porphyrins Phthalocyanines 1997, 1,
77. (c) Yeung, Y.-O.; Liu, R. C. W.; Law, W.-F.; Lau, P.-L.; Jiang,
J.; Ng, D. K. P. Tetrahedron 1997, 53, 9087. (d) Ng, D. K. P.;
Yeung, Y.-O.; Chan, W. K.; Yu, S.-C. Tetrahedron Lett. 1997, 38,
6701. (e) Brewis, M.; Clarkson, G. J.; Humberstone, P.; Makhseed,
S.; McKeown, N. B. Chem. Eur. J. 1998, 4, 1633.
10. (a) Kitahara, K.; Asano, T.; Hamano, K.-I.; Tokita, S.; Nishi,
H. J. Heterocycl. Chem. 1990, 27, 2219. (b) Kitahara, K.; Asano,
T.; Kayama, S.; Tokita, S.; Nishi, H. Phosphorus, Sulfur Silicon
1992, 67, 373.
11. Takahashi, K.; Kawashima, M.; Tomita, Y.; Itoh, M. Inorg.
Chim. Acta 1995, 232, 69.
Acknowledgements
12. Satisfactory analytical data for 6 could not be obtained, but it
was deemed to be pure by chromatographic and spectroscopic
analyses. The experimental carbon content for 11 and 12 was
slightly lower than the corresponding calculated value which
could be related to the dif®culty in complete combustion of these
macrocycles (see Hu, M.; Brasseur, N.; Yildiz, S. Z., van Lier, J.
E.; Leznoff, C. C. J. Med. Chem. 1998 41, 1789).
Financial support from the Hong Kong Research Grants
Council and The Chinese University of Hong Kong is
gratefully acknowledged.
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