Synthesis, characterization, photophysical and photochemical properties of 7-oxy-3-methyl-4-phenylcoumarin-substituted indium phthalocyanines

Article abstract of DOI:10.1016/j.ica.2011.03.066

The synthesis of tetra- and octa-(7-oxy-3-methyl-4-phenylcoumarin)- substituted indium(III) phthalocyanine complexes obtained from 3-nitrophthalonitrile, 4-nitrophthalonitrile and 4,5-dichlorophthalonitrile substituted with 7-oxy-3-methyl-4-phenylcoumarin

Full text of DOI:10.1016/j.ica.2011.03.066

Inorganica Chimica Acta 373 (2011) 107–116
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Inorganica Chimica Acta
journal homepage: www.elsevier.com/locate/ica
Synthesis, characterization, photophysical and photochemical properties
of 7-oxy-3-methyl-4-phenylcoumarin-substituted indium phthalocyanines
Mehmet Pisßkin a, Mahmut Durmusß b, Mustafa Bulut a,
⇑
a Marmara University, Faculty of Art and Science, Department of Chemistry, 34722 Kadikoy, Istanbul, Turkey
b Gebze Institute of Technology, Department of Chemistry, P.O. Box 141, Gebze 41400, Kocaeli, Turkey
a r t i c l e i n f o
a b s t r a c t
Article history:
The synthesis of tetra- and octa-(7-oxy-3-methyl-4-phenylcoumarin)-substituted indium(III) phthalocy-
anine complexes obtained from 3-nitrophthalonitrile, 4-nitrophthalonitrile and 4,5-dichlorophthalonitri-
le substituted with 7-oxy-3-methyl-4-phenylcoumarin are described for the first time in this study. The
new compounds have been characterized by elemental analysis, IR, 1H NMR, electronic spectroscopy and
mass spectra. The photophysical and photochemical properties of the compounds are also studied in
dimethylformamide (DMF). The effects of the number of the substitution and the position on the photo-
physical and photochemical parameters of the substituted indium(III) phthalocyanine complexes are also
reported. Photophysical and photochemical properties of phthalocyanine complexes are very useful for
photodynamic therapy (PDT) of cancer applications. In particular, high singlet-oxygen quantum yields
are very important for Type II mechanisms. These complexes have good singlet-oxygen quantum yields
and show potential as Type II photosensitizers.
Received 8 December 2010
Received in revised form 18 March 2011
Accepted 28 March 2011
Available online 3 April 2011
Keywords:
Coumarin (2H-chromen-2-one)
Fluorescence
Phthalocyanine
Quantum yield
Singlet oxygen
Indium
Ó 2011 Elsevier B.V. All rights reserved.
1. Introduction
a plethora of ways by changing the peripherally or non-peripher-
ally substitution, tetra or octa-substituents on the Pc ring in addi-
Coumarin and its derivatives have been found to show a wide
range of bioactivities such as anticoagulant, estrogenic, dermal
photosensitizing, vasodilator, molluscacidal, anthelmintic, sedative,
hypnotic, analgesic, hypothermic [1], antimicrobial [2], anti-inflam-
matory [3], antifungal [4] and antiulcer [5]. 7-Hydroxycoumarin,
also known as umbelliferone is a major biotransformed product of
coumarin (1,2-benzopyrone), which is a widely distributed natural
product [6]. Coumarins and 7-hydroxycoumarins have been also
found to exhibit cytotoxic effects against the lung adenocarcinoma
cell lines KB [4], A549 [7], SK-LU-1,1.3.15, 3A5A and A-427 [8].
Phthalocyanines are used in a number of applications due to
their increased stability, architectural flexibility, diverse coordina-
tion properties and improved spectroscopic characteristics. Metall-
ophthalocyanines (MPcs), a family of aromatic macrocycles based
tion to changing the central metal and the axial ligands. Their
physicochemical properties can be fine-tuned by changing the me-
tal and/or nature of substituents [13].
Although metallophthalocyanine complexes have been exten-
sively studied, their properties cannot be fully exploited as they
have low solubility in most organic solvents and they aggregate.
Depending on the polarity of the substituents, Pcs become more
soluble in polar or non-polar solvents. Pcs soluble in polar solvents
have strong influence on bioavailability whereas Pcs soluble in non-
polar solvents have a higher tumor affinity [14]. The solubility can
be increased, however, by introducing alkyl or alkoxy groups into
the peripheral and non-peripheral positions of the phthalocyanine
framework [15]. Tetra-substituted phthalocyanines are usually
more soluble than the corresponding octa-substituted phthalocya-
nines due to the formation of constitutional isomers and the high
dipole moment that results from the unsymmetrical arrangement
of the substituents at the periphery [15,16]. According to their sub-
stituent positions, two types of tetra-substituted macrocycles,
which show significant differences in their chemical and physical
behaviors can be distinguished. Substitution at the more sterically
crowded non-peripheral position causes reduced aggregation ten-
dencies more than substitution at peripheral position [17].
on an extensive delocalized 18
p electron system, are known not
only as classical dyes in practical use but also as modern functional
materials in scientific research. Some technological applications in
fields, such as chemical sensors [9], liquid crystals [10], semicon-
ductors [9b], non-linear optics [11], as photosensitizers in photo-
dynamic therapy (PDT) [12], have shown the increased
importance of these macrocycles. The MPcs can be modulated in
Metallophthalocyanine complexes have proved to be highly
promising as photosensitizers for photodynamic therapy (PDT),
due to their intense absorption in the red region of the visible light.
⇑
Corresponding author. Tel.: +90 216 3479641/1370; fax: +90 216 3478783.
E-mail addresses: mbulut@marmara.edu.tr, mustafabulut50@gmail.com
(M. Bulut).
0020-1693/$ - see front matter Ó 2011 Elsevier B.V. All rights reserved.
doi:10.1016/j.ica.2011.03.066

108
M. Pißskin et al. / Inorganica Chimica Acta 373 (2011) 107–116
High triplet state quantum yields and long triplet lifetimes are re-
quired for an efficient sensitization. The photophysical properties
of the phthalocyanine dyes are strongly influenced by the presence
and nature of the central metal ion. Complexation of phthalocya-
nine with transition metals gives dyes short triplet lifetimes.
Closed shell, diamagnetic ions, such as Zn2+, Al3+ and In3+, give
phthalocyanine complexes both high triplet yields and singlet oxy-
gen generation [18]. Heavy metals, especially diamagnetic metals,
play a major role in photosensitizing and optical limiting mecha-
nisms because they enhance intersystem crossing through spin–
orbit coupling. This is desirable because it improves the chances
of getting a large population in the triplet state. Axial ligands in
MPcs are useful in preventing or minimizing intermolecular inter-
actions which result in aggregation in solution. Aggregation can re-
sult in the fast decay of the excited states. Indium is a useful
central metal in MPc complexes since it is diamagnetic and able
to host axial ligands. Indium phthalocyanines have been reported
to have good photosensitizing and optical limiting properties [19].
To our knowledge, coumarin tetra-substitution and octa-substi-
tution on indium acetate based phthalocyanines has not been re-
ported before. The rarity of these phthalocyanines has thus
prompted us to synthesize coumarin substituted indium phthalo-
cyanines (9–12) because the development and elucidation of
photophysical and photochemical properties of new phthalocya-
nine complexes are of fundamental importance. Specific phthalo-
cyanines can thus be tailored such that they have certain
properties, which are required for various applications, since the
possibility of combining an unlimited number and type of substit-
uents with a great number of central metals is infinite.
The syntheses of indium(III) Pc complexes (9–12) were achieved
by treatment of 7-oxy-3-methyl-4-phenylcoumarin-substituted
phthalonitriles (5–8) with anhydrous indium(III) acetate in N,N-
dimethylaminoethanol (DMAE) (Scheme 1). Column chromatogra-
phy with silica gel was employed to obtain the pure products from
the reaction mixtures. Generally, phthalocyanine complexes are
insoluble in most organic solvents; however introduction of sub-
stituents on the ring increases the solubility. All phthalocyanine
complexes (9–12) exhibited excellent solubility in organic solvents
such as dichloromethane, chloroform, THF, DMF and DMSO. The
new compounds were characterized by UV–Vis, FT-IR and NMR
spectroscopies, MALDI-TOF mass spectra and elemental analysis.
The analyses are consistent with the predicted structures as shown
in Section 3.
Comparison of the IR spectra at each step gave some insights on
the nature of the products. The –OH stretching band of 7-hydroxy-
3-methyl-4-phenylcoumarin group at 3141 cmꢀ1 disappeared for
all the dinitrile compounds in the IR spectra. The IR spectra of
the all dinitrile compounds showed a sharp peak at around
2230–2245 cmꢀ1 for C„N stretching. These peaks disappeared
and the color changed to green after conversion, indicative of
phthalocyanines formation.
The 1H NMR spectra of substituted dinitrile compounds (5–8)
were recorded in CDCl3. We were able to obtain good aromatic
and methyl protons signals for 1H NMR spectroscopy. In the 1H
NMR spectra of substituted dinitrile compounds (5–8), the aro-
matic protons were observed at between 7.65 and 6.87 ppm for
compound 5, 7.78–6.84 ppm for compound 6, 7.92–6.82 ppm for
compound 7 and 7.55–6.80 ppm for compound 8 integrating to-
tally 11 protons for compounds 5 and 6, 10 protons for compounds
7 and 18 protons for compound 8. The aliphatic methyl protons
were observed at ꢁ2 ppm for all dinitrile compounds integrating
3 protons for each compound.
The aim of our ongoing research is to synthesize indium phthal-
ocyanines as potential PDT agents. Photophysical and photochem-
ical properties of InPcs are very useful in applications involving
PDT, non-linear optics and optical limiters as these indium macro-
cycles are known to have remarkable properties [20]. Herein, we
report the synthesis, spectroscopic, photophysical and photochem-
ical properties of InPc tetra-substituted at the non-peripheral (9),
peripheral (10) and octa-substituted (11 and 12) at the peripheral
positions with 7-oxy-3-methyl-4-phenylcoumarin (Scheme 1).
In the mass spectra of phthalonitriles obtained by the MALDI-
TOF technique, the molecular ion peaks were observed at m/z:
378.1 [M]+ for 5, 378.7 [M]+ for 6, 412.0 [M]+ for 7 and 628.9
[M]+ for 8.
The C„N stretching peaks of the dinitrile compounds at around
2230–2245 cmꢀ1 disappeared after formation of the phthalocya-
nine complexes. In the IR spectra for Pc complexes (9–12), vibra-
tions bands were observed at: 3038–3075 cmꢀ1 for aromatic C–H
stretchinꢀg1, 2840–2923 cmꢀ1 for aliphatic C–H stretching, 1710–
2. Results and discussion
2.1. Synthesis and characterization
1720 cm
for C@O vibration of the ester groups, 1582–
1678 cmꢀ1 for aromatic C@C stretching and 1237–1278 cmꢀ1 for
Ar–O–Ar stretching. The C@O and C@C bands for indium(III) phtha-
locyanine complexes (9–12) in IR spectra were broader and shorter
than those of dinitrile compounds (5–8) because of the H-type
aggregation of coumarin moiety.
Tetra- and octa-substituted indium(III) phthalocyanine com-
plexes (9–12) are prepared by cyclotetramerization of 7-hydoxy-
3-methyl-4-phenylcoumarin-substituted phthalonitriles (5–8). In
both cases, a mixture of four possible structural isomers is ob-
tained. The four probable isomers can be designed by their molec-
ular symmetry as C4h, C2v, Cs and D2h. In this study, synthesized
tetra-(7-oxy-3-methyl-4-phenyl)coumarin-substituted indium(III)
Pc complexes are obtained as isomer mixtures as expected. No at-
tempt was made to separate the isomers of complexes 9 and 10.
The preparation of substituted phthalonitriles from 3-nitropht-
halonitrile (2), 4-nitrophthalonitrile (3) and 4,5-dichlorophthalo-
nitrile (4) were recently used to prepare 3-monosubstituted,
4-monosubstituted and 4,5-disubstituted phthalonitrile deriva-
tives, respectively, through base catalyzed nucleophilic aromatic
displacement [21]. The same route was applied to prepare 7-oxy-
3-methyl-4-phenylcoumarin-substituted phthalonitriles from
7-hydroxy-3-methyl-4-phenylcoumarin (1) and 3-nitrophthalonit-
rile (2), 4-nitrophthalonitrile (3) or 4,5-dichlorophthalonitrile (4)
(Scheme 1). The reactions were carried out in dimethylformamide
(DMF) at room temperature and gave yields of about 80–90%.
The preparation of phthalocyanine derivatives from the aro-
matic 1,2-dinitriles occurs under different reaction conditions.
The 1H NMR spectra of Pcs (9–12) were recorded in CDCl3. The
1H NMR spectra of tetra-substituted phthalocyanine complexes (9–
12) have broad absorptions when compared with that of corre-
sponding phthalonitrile derivatives (5–8). It is likely that broad-
ness is due to both chemical exchange caused by aggregation–
disaggregation equilibrium in CDCl3 and the fact that the product
obtained in this reaction is a mixture of four positional isomers
(for tetra-substituted complexes) which are expected to show
chemical shifts which slightly differ from each other. The 7-oxy-
3-methyl-4-phenylcoumarin-substituted indium(III) Pc complexes
were found to be pure by 1H NMR with all the substituents and
ring protons observed in their respective regions. In the 1H NMR
spectra of Pcs (9–12), the aromatic protons were observed at be-
tween 8.01 and 6.92 ppm for compound 9, 8.25–6.72 ppm for com-
pound 10, 7.91–6.98 ppm for compound 11 and 7.98–6.76 ppm for
compound 12 integrating totally 44, 44, 40, 72 protons for each Pcs,
respectively. The aliphatic methyl protons were observed at 2.55,
2.81, 2.54, 2.59 ppm for all Pcs, respectively, integrating 12 protons

M. Pißskin et al. / Inorganica Chimica Acta 373 (2011) 107–116
109
OR
OOCCH3
OR
NO2
OR
N
N
N
N
N
CN
CN
CN
CN
O
OH
O
i
ii
N
+
In
N
N
OR
5
2
RO
9
1
OR
N
OOCCH3
N
CN
CN
N
N
N
RO
O
OH O2N
CN
CN
O
i
ii
RO
+
In
N
N
N
OR
6
3
10
1
OR
Cl
OR
OOCCH3
N
O
OH
O
N
N
N
N
Cl
CN
CN
CN
CN
RO
Cl
RO
Cl
i
ii
+
In
N
N
Cl
Cl
OR
N
4
7
11
1
RO
RO
Cl
OR
OOCCH3
OR
N
N
N
N
N
Cl
Cl
CN
CN
O
OH
+
RO
RO
CN
CN
O
RO
RO
ii
i
N
N
In
N
OR
4
8
12
O
O
O
RO
OR
1
R =
Scheme 1. Synthesis of tetra- and octa-(7-oxy-3-methyl-4-phenylcoumarin)-substituted indium(III) phthalocyanine complexes (9–12). (i) DMF, K2CO3, RT; (ii) DMAE,
In(OAc)3, reflux.
for each Pcs (9, 10 and 11) and 24 protons (12). The indium(III) ace-
tate protons were observed at 2.51, 2.81, 2.60 and 2.12 ppm for all
Pcs, respectively, integrating 3 protons for each Pcs (9, 10, 11 and
12).
In the mass spectra of phthalocyanines obtained by the MALDI-
TOF technique, the molecular ion peaks were observed at m/z:
1627.5 for 9, 1627.4 for 10, 1766.1 for 11 and 2628.5 for 12 as
without axially substituted acetate groups.
DMF, Table 1. The B bands were observed at around 320 nm
(Fig. 1). The spectra showed monomeric behavior evidenced by a
single (narrow) Q band, typical of metallated phthalocyanine com-
plexes in DMF [22]. In DMF, the Q bands were observed at: 705 nm
for 9, 687 nm for 10, 677 nm for 11 and 683 nm for 12, Table 1. The
red-shifts were observed for indium(III) Pc complexes following
substitution. The Q band of the non-peripherally substituted com-
plex (9) is red-shifted when compared to the corresponding
peripherally tetra-(10) and octa-(11 and 12) substituted complexes
in DMF (Fig. 1). The red-shifts are 18 nm between 9 and 10, 28 nm
between 9 and 11 and 22 nm between 9 and 12. The observed red
spectral shifts are typical of Pcs with substituents at the non-
peripheral positions and have been explained in the literature
[23], due to linear combination of the atomic orbitals (LCAO)
2.2. Ground state electronic absorption spectra
The electronic spectra of the 7-oxy-3-methyl-4-phenylcouma-
rin-substituted indium(III) Pc complexes (9–12) showed character-
istic absorption in the Q band region at around 677–705 nm in

110
M. Pißskin et al. / Inorganica Chimica Acta 373 (2011) 107–116
Table 1
Absorption, excitation and emission spectral data for unsubstituted (InPc) and substituted indium phthalocyanines (9–12) in DMF.
Compound
Q band kmax (nm)
(log
e
)
Excitation kEx (nm)
Emission kEm (nm)
Stokes shift DStokes (nm)
InPca
9
10
11
12
681
705
687
677
683
5.04
5.01
4.68
4.30
4.86
681
713
689
679
682
696
721
698
684
686
15
16
11
7
3
a
Data from Ref. [29].
1.2
0.8
0.4
9
12
10
11
0
300
400
500
600
700
800
Wavelength (nm)
Fig. 1. Absorption spectra of substituted indium phthalocyanine complexes (9, 10, 11 and 12) in DMF. Concentration = 1 ꢂ 10ꢀ5 M.
coefficients at the non-peripheral positions of the highest occupied
molecular orbital (HOMO) being greater than those at the periph-
eral positions. As a result, the HOMO level is more destabilized
upon non-peripherally substitution than peripherally substitution.
ples of the studied indium(III) Pc complexes. Fluorescence
emission peaks were listed in Table 1. All indium(III) Pc complexes
(9–12) showed similar fluorescence behavior in DMF (Fig. 3 as an
example for complexes 10 and 11). The excitation spectra were
similar to absorption spectra and both were mirror images of the
fluorescent spectra for all indium(III) Pc complexes in DMF. The
proximity of the wavelength of each component of the Q-band
absorption to the Q band maxima of the excitation spectra for all
indium(III) Pc complexes suggest that the nuclear configurations
of the ground and excited states are similar and not affected by
excitation. The fluorescence emission of the chloro octa-substi-
tuted indium(III) Pc complex (11) is more intense than other stud-
ied indium(III) phthalocyanine complexes (9, 10 and 12) in DMF,
suggesting that heavy atom effect of the chlorine atoms on the
Pc framework instead of H atoms.
Essentially, the energy gap (DE) between the HOMO and lowest
unoccupied molecular orbital (LUMO) becomes smaller, resulting
in a ꢁ20 nm bathochromic shift. The shoulder between 360 and
370 nm may be due to charge transfer from the electron-rich ring
to the electron-poor metal. The B-bands are broad due to the
superimposition of the B1 and B2 bands in the ꢁ320 nm region.
2.3. Aggregation studies
Aggregation is usually depicted as a coplanar association of
rings progressing from monomer to dimer and higher order com-
plexes. It is dependent on the concentration, nature of the solvent,
nature of the substituents, complexed metal ions and temperature
[24]. In the aggregated state the electronic structure of the com-
plexed phthalocyanine rings are perturbed resulting in alternation
of the ground and excited state electronic structures [25]. In this
study, the aggregation behavior of 7-oxy-3-methyl-4-phenylcoum-
arin-substituted indium(III) Pc complexes (9–12) were investi-
gated at different concentrations in DMF (Fig. 2, for complex 10
as an example). The Beer–Lambert law was obeyed for all of these
compounds at concentrations ranging from 1.4 ꢂ 10ꢀ5 to
4 ꢂ 10ꢀ6 M. The 7-oxy-3-methyl-4-phenylcoumarin-substituted
indium(III) Pc complexes did not show aggregation at these con-
centration ranging in DMF.
2.5. Fluorescence quantum yields and lifetimes
The fluorescence quantum yields (UF) of the studied indium Pc
complexes are given in Table 2. The UF values of indium(III) Pc
complexes are lower than other MPc complexes because of the in-
dium is very heavy metal, Table 2. The UF values of the indium Pc
complexes are similar and typical of other studied indium Pc com-
plexes in DMF [26], except for chloro octa-substituted indium(III)
Pc complex (11). This complex showed higher UF value due to
the heavy atom effect of the chlorine atom on the Pc framework
(Table 2). The UF values of the substituted indium Pc complexes
(9–12) are higher compared to unsubstituted indium Pc complex
(InPc) in DMF, which implies that the presence of the 7-oxy-3-
methyl-4-phenylcoumarin substituents reduced the fluorescence
quenching of the molecules. For comparison among the studied in-
dium(III) Pc complexes, the UF values of the octa-substituted in-
dium(III) Pc complexes are higher than tetra-substituted
indium(III) Pc complexes which suggesting that the increasing of
2.4. Fluorescence spectra
Fig. 3 shows fluorescence emission, absorption and excitation
spectra of 7-oxy-3-methyl-4-phenylcoumarin-substituted indiu-
m(III) Pc complexes 10 (Fig. 3a) and 11 (Fig. 3b) in DMF as exam-

M. Pißskin et al. / Inorganica Chimica Acta 373 (2011) 107–116
111
0.8
0.6
0.4
0.2
0
0.8
0.6
0.4
0.2
0
y = 48400x + 0.0427
R2 = 0.9997
A
B
C
D
E
F
0.00E+00 2.00E-06 4.00E-06 6.00E-06 8.00E-06 1.00E-05 1.20E-05 1.40E-05 1.60E-05
Concentration
300
400
500
600
Wavelength (nm)
700
800
Fig. 2. Aggregation behavior of 10 in DMF at different concentrations: 14 ꢂ 10ꢀ6 (A), 12 ꢂ 10ꢀ6 (B), 10 ꢂ 10ꢀ6 (C), 8 ꢂ 10ꢀ6 (D), 6 ꢂ 10ꢀ6 (E) and 4 ꢂ 10ꢀ6 (F) M. (Inset: plot of
absorbance vs. concentration.)
300
250
200
150
100
50
0.3
0.25
0.2
0.15
0.1
0.05
0
Excitation
Absorption
(a)
Emission
0
500
550
600
650
700
750
800
Wavelength (nm)
700
600
500
400
300
200
100
0
0.25
0.2
0.15
0.1
0.05
0
(b)
Emission
Excitation
Absorption
500
550
600
650
700
750
800
Wavelength (nm)
Fig. 3. Absorption, excitation and emission spectra of the compound 10 (a) and 11 (b) in DMF. Excitation wavelength = 655 nm for 10 and 650 nm for 11.
the number of the substituents reduced fluorescence quenching of
the Pc molecules.
lifetime of a fluorophore indirectly reduces the value of UF. Such fac-
tors include internal conversion and intersystem crossing. As a re-
sult, the nature and the environment of a fluorophore determine
its fluorescence lifetime. sF values (Table 2) were calculated using
the Strickler–Berg equation. The sF values of the substituted
indium(III) Pc complexes are higher compared to unsubstituted
Fluorescence lifetime (sF) refers to the average time a molecule
stays in its excited state before fluorescing, and its value is directly
related to that of UF; i.e. the longer the lifetime, the higher the quan-
tum yield of fluorescence. Any factor that shortens the fluorescence

112
M. Pißskin et al. / Inorganica Chimica Acta 373 (2011) 107–116
Table 2
11 and 12) are given in Table 2. The UD values of the substituted in-
dium(III) Pc complexes (9, 10 and 12) are higher when compared to
unsubstituted indium(III) Pc (InPc) complex, except for chloro octa-
substituted complex (11) in DMF. The UD value of chloro octa-
substituted complex (11) is lower than other substituted indiu-
m(III) Pc complexes in DMF, because this complex contains heavy
chlorine atoms and these chlorine atoms reduce intersystem cross-
ing. The non-peripherally tetra-substituted indium(III) Pc complex
(9) showed the highest UD value among the studied indium(III) Pc
complexes (Table 2) may be due to their absorption of light at long-
er wavelength than peripherally substitution.
Photophysical and photochemical data for unsubstituted (InPc) and substituted
indium phthalocyanines (9–12) in DMF.
kF (sꢀ1
)
Ud
(ꢂ 10ꢀ3
0.01
1.16
1.10
0.23
0.73
UD
a
Compound UF
sF
(ns)
s0
(ns)
(ꢂ 107)
)
InPcb
9
10
11
12
0.017
0.018
0.033
0.11
0.26
0.87
12.89
14.53
26.26
75.06
17.13
15.5
6.88
3.80
1.33
5.84
0.70
0.83
0.62
0.30
0.76
0.141 10.51
0.055 0.94
a
kF is the rate constant for fluorescence. Values calculated using kF = UF/sF.
Data from Ref. [29].
b
2.7. Photodegradation studies
indium(III) Pc complexes in DMF, suggesting less quenching by sub-
stitution. sF values are lower for tetra-substituted indium Pc com-
plexes (9 and 10) when compared to octa-substituted indium Pc
complexes (11 and 12), Table 2, suggesting more quenching by tet-
Degradation of the molecules under irradiation can be used to
study their stability and this is especially important for those mol-
ecules intended for use as photocatalysts. The collapse of the
absorption spectra without any distortion of the shape confirms
clean photodegradation not associated with photochemical reac-
tion into different forms of MPc absorbing in the visible region.
The spectral changes observed for all the substituted indium Pc
(9–12) during irradiation are as shown in Fig. 5 (using complex 9 as
an example in DMF) and hence confirm photodegradation occurred
without phototransformation. All the complexes showed about the
same stability with Ud of the order of 10ꢀ3. The Ud values, found in
this study, are higher than phthalocyanine derivatives having dif-
ferent metals and substituents on the phthalocyanine ring in the
literature [28]. Stable zinc phthalocyanine molecules show Ud val-
ues as low as 10ꢀ6 and for unstable molecules, values of the order
of 10ꢀ3 have been reported [28]. The Ud values of the substituted
indium(III) Pc complexes (9–12) are also higher than unsubstituted
indium(III) Pc complex in DMF [29]. It seems indium(III) metal and
7-oxy-3-methyl-4-phenylcoumarin groups increases the Ud values
and decreases the stability of complexes.
ra-substitution compared to octa-substitution. However the sF val-
ues are typical for indium(III) Pc complexes [26], the sF value of
chloro octa-substituted indium(III) Pc complex (11) is higher than
other substituted indium(III) Pc complexes (9, 10 and 12) because
of the heavy atom effects of the chlorine atom, again.
The natural radiative lifetime (s0) and the rate constants for
fluorescence (kF) values are also given in Table 2. The s0 values of
the substituted indium Pc complexes (9–12) are higher than
unsubstituted indium Pc complex (InPc) in DMF. The chloro
octa-substituted indium(III) Pc complex showed higher s0 value
than other substituted indium(III) Pc complexes in DMF (Table
2). The rate constants for fluorescence (kF) of substituted indiu-
m(III) Pc complexes (9–12) are lower when compared to unsubsti-
tuted indium(III) Pc (InPc) in DMF. The chloro octa-substituted
complex (11) showed the lowest kF value among the substituted
indium(III) Pc complexes in DMF (Table 2).
2.6. Singlet oxygen quantum yields
3. Experimental
An efficient photosensitizer must be generating singlet oxygen
very effectively for application of photodynamic therapy treatment
of cancer. Energy transfer between the triplet state of a photosensi-
tizer molecule (such as phthalocyanines) and the ground state of
molecular oxygen leads to its conversion into singlet oxygen. This
transfer must be as much efficient as possible to generate large
amounts of singlet oxygen. This is determined as the singlet oxygen
quantum yield (UD), a parameter giving an indication of the poten-
tial of molecules using as photosensitizers in applications where
singlet oxygen is required (e.g., for Type II mechanism) [27]. The
UD values were determined in DMF using a chemical method and
1,3-diphenylisobenzofuran (DPBF) as a quencher. The disappear-
ance of DPBF absorbance at 417 nm was monitored using UV–Vis
spectrophotometer (Fig. 4 for complex 10 as an example).
3.1. Materials
All reagents and solvents were of reagent grade quality and
were obtained from commercial suppliers. 7-Hydroxy-3-methyl-
4-phenylcoumarin (1), indium(III)acetate, K2CO3 and unsubstitut-
ed zinc phthalocyanine were purchased from the Aldrich Chemical
Company. 1,3-Diphenylisobenzofuran (DPBF) was purchased from
Fluka. 3-Nitrophthalonitrile (2) [30], 4-nitrophthalonitrile (3) [31]
and 4,5-dichlorophthalonitrile (4) [32] were synthesized and puri-
fied according to well known literature.
3.2. Equipment
Many factors are responsible for the magnitude of the deter-
mined quantum yield of singlet oxygen including; triplet excited
state energy, ability of substituents and solvents to quench the sin-
glet oxygen, the triplet excited state lifetime and the efficiency of
the energy transfer between the triplet excited state and the ground
state of oxygen. It is believed that during photosensitization, the
phthalocyanine molecule is first excited to the singlet state and
through intersystem crossing forms the triplet state, and then
transfers the energy to ground state oxygen, O2(3Rg), generating ex-
cited singlet state oxygen, O2(1Dg), the chief cytotoxic species,
which subsequently oxidizes the substrate by Type II mechanism.
There was no change in the Q band intensity during the UD
determinations, confirming that complexes were not degraded dur-
ing singlet oxygen studies (Fig. 4 as an example for complex 10).
The UD values of the substituted indium(III) Pc complexes (9, 10,
Absorption spectra in the UV–Vis region were recorded with a
Shimadzu 2001 UV spectrophotometer. Fluorescence excitation
and emission spectra were recorded on a Varian Eclipse spectroflu-
orometer using 1 cm pathlength cuvettes at room temperature. IR
spectra (KBr pellets) were recorded on a Bio-Rad FTS 175C FT-IR
spectrometer. Elemental analyses carried out using a LECO CHN
932 was performed by the Instrumental Analysis Laboratory of
TUBITAK Ankara Test and Analysis Laboratory. Mass spectra were
performed on a Bruker Autoflex III MALDI-TOF spectrometer. A
2,5-dihydroxybenzoic acid (DHB, 20 mg/mL in THF) was used as ma-
trix. MALDI samples were prepared by mixing the complex (2 mg/
mL in THF) with the matrix solution (1:10 v/v) in a 0.5 mL Eppendorf
micro tube. Finally, 1
lL of this mixture was deposited on the sample
plate, dried at room temperature and then analyzed. 1H NMR spectra

M. Pißskin et al. / Inorganica Chimica Acta 373 (2011) 107–116
113
1
0.8
0.6
0.4
0.2
0
0 sec
1
5 sec
y = -0.0317x + 0.9352
2 = 0.9858
0.8
0.6
0.4
0.2
0
R
10 sec
15 sec
20 sec
0
5
10
Time (sec)
15
20
300
400
500
600
700
800
Wavelength (nm)
Fig. 4. A typical spectrum for the determination of singlet oxygen quantum yield. This determination was for compound 10 in DMF at a concentration of 1 ꢂ 10ꢀ5 M. (Inset:
plot of DPBF absorbance vs. time.)
1.4
1.4
1.2
1
y = -0.0021x + 1.1843
2 = 0.9949
R
1.2
1
0.8
0.6
0.4
0.2
0
0 sec
60 sec
120 sec
180 sec
240 sec
300 sec
0.8
0.6
0.4
0.2
0
0
50
100
150
200
250
300
Time (sec)
300
400
500
600
700
800
Wavelength (nm)
Fig. 5. The photodegradation of compound 9 in DMF showing the disappearance of the Q-band at 1 min intervals. (Inset: plot of absorbance vs. time.)
and AStd are the respective absorbances of the samples and standard
at the excitation wavelengths, respectively. n2 and nS2td are the
refractive indices of solvents used for the sample and standard,
respectively. Unsubstituted ZnPc (in DMSO) (UF = 0.20) [34] was
employed as the standard. The absorbance of the solutions at the
excitation wavelength ranged between 0.04 and 0.05.
were recorded in CDCl3 for phthalonitriles (5–8) and phthalocyanine
complexes (9–12) on a Varian 500 MHz spectrometer.
Photo-irradiations were done using a General Electric quartz
line lamp (300 W). A 600 nm glass cut off filter (Schott) and a water
filter were used to filter off ultraviolet and infrared radiations,
respectively. An interference filter (Intor, 670 nm with a band
width of 40 nm) was additionally placed in the light path before
the sample. Light intensities were measured with a POWER
MAX5100 (Molelectron detector incorporated) power meter.
Natural radiative (
s0) lifetimes were determined using Photo-
chemCAD program which uses the Strickler–Berg equation [35].
The fluorescence lifetimes (sF) were evaluated using Eq. (2).
sF
s0
UF
¼
ð2Þ
3.3. Photophysical parameters
3.3.1. Fluorescence quantum yields and lifetimes
Fluorescence quantum yields (UF) were determined by the
comparative method using Eq. (1) [33],
3.4. Photochemical parameters
3.4.1. Singlet oxygen quantum yields
Singlet oxygen (UD) quantum yield determinations were car-
ried out using the experimental set-up described in the literature
[36], in DMF. Typically, a 3 mL portion of the respective substituted
indium(III) phthalocyanine (9–12) solutions (absorbance ꢁ1 at the
irradiation wavelength) containing the singlet oxygen quencher
F ꢃ AStd ꢃ n2
UF
¼
UFðStdÞ
ð1Þ
FStd ꢃ A ꢃ n2Std
where F and FStd are the areas under the fluorescence emission
curves of the samples (9–12) and the standard, respectively. A

114
M. Pißskin et al. / Inorganica Chimica Acta 373 (2011) 107–116
was irradiated in the Q band region with the photo-irradiation set-
up described in references [36]. Singlet oxygen quantum yields
in dry DMF (9 mL) under argon atmosphere. After stirring for
15 min, finely ground anhydrous K2CO3 (0.54 g, 3.91 mmol) was
added portionwise over 2 h and the ensuing mixture was stirred
vigorously at room temperature for a further 48 h. The reaction
mixture was then poured into water (150 mL) and the precipitate
was filtered off and washed with water to the white product. The
compound 6 is soluble in chloroform, dichloromethane, tetrahy-
drofurane, dimethylformamide and dimethylsulfoxide. Yield:
(UD) were determined in air using the relative method with
unsubstituted ZnPc (in DMF) as reference. DPBF was used as
chemical quenchers for singlet oxygen in DMF. Eq. (3) was
employed for the calculations:
Std
R ꢃ I
USDtd
ð3Þ
abs
UD
¼
RStd ꢃ Iabs
0.60 g (%80). Mp 115 °C. FT-IR [(KBr) m
max/cmꢀ1]: 3065 (Ar–CH),
2957–2804 (CH), 2239 (C„N), 1704 (C@O lactone), 1576 and
1470 (C@C), 1254 (Ar–O–Ar). 1H NMR (CDCl3): d, ppm: aromatic
protons, 7.78 (d, 8.30 Hz, 1H), 7.58 (d, 2.44 Hz, 1H), 7.57 (d,
7.81 Hz, 1H), 7.53 (t, 1H), 7.33 (d, 8.54 Hz, 2H), 7.26 (d, 8.05 Hz,
2H), 7.10 (d, 8.54 Hz, 1H), 7.09 (d, 2.20 Hz, 1H), 6.84 (dd, 8.79 Hz,
2.44 Hz, 1H), 2.02 (s, 3H, CH3). Anal. Calc. for C24H14N2O3
(378.38): C, 76.18; H, 3.73; N, 7.40. Found: C, 76.15; H, 3.76; N,
7.37%. MS (MALDI-TOF) m/z: 378.79 [M]+.
where USDtd is the singlet oxygen quantum yields for the standard
ZnPc (USDtd ¼ 0:56 in DMF) [34]. R and RStd are the DPBF photoble-
aching rates in the presence of the respective samples (9–12) and
standards, respectively. Iabs and IStd are the rates of light absorption
abs
by the samples (9–12) and standards, respectively. To avoid chain
reactions induced by DPBF in the presence of singlet oxygen [37],
the concentration of quenchers was lowered to ꢁ3 ꢂ 10ꢀ5 M. Solu-
tions of sensitizer (1 ꢂ 10ꢀ5 M) containing DPBF was prepared in
the dark and irradiated in the Q band region using the set-up de-
scribed above. DPBF degradation at 417 nm was monitored. The
light intensity 6.72 ꢂ 1015 photons sꢀ1 cmꢀ2 was used for UD
determinations.
3.5.3. 4-Chloro-5-(3-methyl-4-phenyl-2H-chromen-7-
yloxy)phthalonitrile (7, Scheme 1)
7-Hydroxy-3-methyl-4-phenylcoumarin (1) (0.5 g, 1.98 mmol)
and 4,5- dichlorophthalonitrile (4) (0.39 g, 1.98 mmol) were dis-
solved in dry DMF (9 mL) under argon atmosphere. After stirring
for 10 min; finely ground anhydrous K2CO3 (0.54 g, 3.96 mmol)
was added with stirring. The reaction mixture was stirred at room
temperature for 48 h under argon atmosphere. The reaction mix-
ture was then poured into water (150 mL) and the precipitate
was filtered off and washed with water to the white product. The
compound 7 is soluble in chloroform, dichloromethane, tetrahy-
drofurane, dimethylformamide and dimethylsulfoxide. Yield:
3.4.2. Photodegradation quantum yields
Photodegradation quantum yield (Ud) determinations were car-
ried out using the experimental set-up described in the literature
[36]. Photodegradation quantum yields were determined using
Eq. (4),
ðC0 ꢀ CtÞ ꢃ V ꢃ NA
Ud
¼
ð4Þ
Iabs ꢃ S ꢃ t
0.65 g (79%). Mp 103 °C. FT-IR [(KBr) m
max/cmꢀ1]: 3062 (Ar–CH),
where C0 and Ct are the samples (9–12) concentrations before and
after irradiation, respectively, V is the reaction volume, NA is the
Avogadro’s constant, S is the irradiated cell area, t is the irradiation
time and Iabs is the overlap integral of the radiation source light
intensity and the absorption of the samples (9–12). A light intensity
2920 (CH), 2245 (C„N), 1730 (C@O lactone), 1580 (C@C), 1252
(Ar–O–Ar). 1H NMR (CDCl3): d, ppm: aromatic protons: 7.92 (s,
1H), 7.58 (d, 8.30 Hz, 2H), 7.54 (d, 8.55 Hz, 2H), 7.52 (t, 1H), 7.19
(s, 1H), 7.12 (d, 8.79 Hz, 1H), 7.08 (d, 1.46 Hz, 1H), 6.82 (dd,
8.79 Hz, 1.46 Hz, 1H), 2.02 (s, 3H, CH3). Anal. Calc. for C24H13ClN2O3
(412.82): C, 69.83; H, 3.17; N, 6.79. Found: C, 69.73; H, 3.19; N,
6.6%. MS (MALDI-TOF) m/z: 412.06 [M]+.
of
2.25 ꢂ 1016 photons sꢀ1 cmꢀ2
was
employed for Ud
determinations.
3.5. Synthesis
3.5.4. 4,5-Bis(3-methyl-2-oxo-4-phenyl-2H-chromen-7-
yloxy)phthalonitrile (8, Scheme 1)
3.5.1. 3-(3-Methyl-2-oxo-4-phenyl-2H-chromen-7-
7-Hydroxy-3-methyl-4-phenylcoumarin (1) (0.6 g, 2.38 mmol)
and 4,5-dichlorophthalonitrile (4) (0.19 g, 1.19 mmol) were dis-
solved in dry DMF (12 mL) under argon atmosphere. After stirring
for 10 min; finely ground anhydrous K2CO3 (1.09 g, 9.52 mmol)
was added with stirring. The reaction mixture was stirred at room
temperature for 72 h under argon atmosphere. The reaction mix-
ture was then poured into water (150 mL) and the precipitate
was filtered off and washed with water to the white product. The
compound 8 is soluble in chloroform, dichloromethane, tetrahy-
drofurane, dimethylformamide and dimethylsulfoxide. Yield:
yloxy)phthalonitrile (5, Scheme 1)
7-Hydroxy-3-methyl-4-phenycoumarin (1) (0.5 g, 1.98 mmol)
and 3-nitrophthalonitrile (2) (0.34 g, 1.98 mmol) were dissolved in
dry DMF (9 mL) under argon atmosphere. After stirring for 15 min,
finely ground anhydrous K2CO3 (0.54 g, 3.91 mmol) was added por-
tionwise over 2 h and the ensuing mixture was stirred vigorously at
room temperature for a further 48 h. The reaction mixture was then
poured into water (150 mL) and the precipitate was filtered off and
washed with water to the white product. The compound 5 is soluble
in chloroform, dichloromethane, tetrahydrofurane, dimethylform-
amide and dimethylsulfoxide. Yield: 0.59 g (%79). Mp 126 °C. FT-IR
0.58 g (77%). Mp 121 °C. FT-IR [(KBr) m
max/cmꢀ1]: 3040 (Ar–CH),
2880–2946 (CH), 2240 (C„N), 1720 (C@O, lactone), 1480 (C@C),
1254 (Ar–O–Ar). 1H NMR (CDCl3): d, ppm: aromatic protons, 7.55
(d, 7.57 Hz, 4H), 7.51 (t, 2H), 7.35 (s, 2H), 7.26 (d, 8.06 Hz, 4H),
7.07 (d, 8.79, 2H), 7.01 (d, 2.20 Hz, 2H), 6.80 (dd, 8.79 Hz,
2.20 Hz, 2H), 2.00 (s, 6H, CH3). Anal. Calc. for C40H24N2O6
(628.63): C, 76.42; H, 3.85; N, 4.46. Found: C, 75.90; H, 3.92; N,
4.38%. MS (MALDI-TOF) m/z: 628.98 [M]+.
[(KBr) m
max/cmꢀ1]: 3056 (Ar–CH), 2960 (CH), 2229 (C„N), 1724
(C@O lactone), 1460 (C@C), 1265 (Ar–O–Ar). 1H NMR (CDCl3): d,
ppm: aromatic protons, 7.65 (t, 1H), 7.57 (d, 7.33 Hz, 1H), 7.55 (d,
7.57 Hz, 1H), 7.54 (d, 8.79 Hz, 2H), 7.51 (t, 1H), 7.25 (d, 8.05 Hz,
2H), 7.23 (d, 8.79 Hz, 1H), 7.06 (d, 2.19 Hz, 1H,), 6.87 (dd, 8.79 Hz,
2.44 Hz, 1H), 2.00 (s, 3H, CH3). Anal. Calc. for C24H14N2O3 (378.38):
C, 76.18; H, 3.73; N, 7.40. Found: C, 76.14; H, 3.77; N, 7.36%. MS
(MALDI-TOF) m/z: 378.10 [M]+.
3.5.5. 1(4),8(11),15(18),22(25)-Tetrakis(3-methyl-2-oxo-4-phenyl-
2H-chromen-7-yloxy)phthalocyaninato indium(III) acetate (9, Scheme
1)
The compound 5 (0.5 g, 1.32 mmol), anhydrous indium(III)ace-
tate (0.19 g, 0.65 mmol) and dried N,N-dimethylamino ethanol
(2 mL) were refluxed with stirring under argon atmosphere for
3.5.2. 4-(3-Methyl-2-oxo-4-phenyl-2H-chromen-7-
yloxy)phthalonitrile (6, Scheme 1)
7-Hydroxy-3-methyl-4-phenylcoumarin (1) (0.5 g, 1.98 mmol)
and 4-nitrophthalonitrile (3) (0.34 g, 1.98 mmol) were dissolved

M. Pißskin et al. / Inorganica Chimica Acta 373 (2011) 107–116
115
24 h. After cooling to room temperature, the solution was dropped
in the hot methanol and then filtered off. The green solid product
was precipitated and collected by filtration and washed with sev-
eral times with hot methanol, ethanol, ethyl acetate, acetonitrile,
acetone, diethyl ether and dried. The green product was purified
by passing through a silica gel column using chloroform as the
eluting solvent. The compound 9 is soluble in chloroform, dichloro-
methane, tetrahydrofurane, dimethylformamide and dimethylsulf-
3.5.8. 2,3,9,10,16,17,23,24-Octakis(3-methyl-2-oxo-4-phenyl-2H-
chromen-7-yloxy)phthalocyaninato indium(III) acetate (12, Scheme 1)
The compound 8 (0.5 g, 0.79 mmol), anhydrous indium(III) ace-
tate (0.19 g, 0.65 mmol) and dried N,N-dimethylaminoethanol
(2 mL) were refluxed with stirring under argon atmosphere for
24 h. After cooling to room temperature, the solution was dropped
in the hot methanol and then filtered off. The green solid product
was precipitated and collected by filtration and washed several
times with hot methanol, ethanol, ethyl acetate, acetonitrile, ace-
tone, diethyl ether and dried. The green product was purified by
passing through a silica gel column, using chloroform as the eluting
solvent. The compound 12 is soluble in chloroform, dichlorometh-
ane, tetrahydrofurane, dimethylformamide and dimethylsulfoxide.
oxide. Yield: 0.17 g (31%). Mp > 300 °C. UV–Vis kmax (nm) (log
(DMF): 320 (4.81), 632 (4.27), 705 (5.01). FT-IR [(KBr) mmax
e
)
/
cmꢀ1]: 3038 (Ar–H), 2923–2840 (CH), 1710 (C@O, lactone), 1607
(C@C), 1582 (C@C), 1274 (Ar–O–Ar). 1H NMR (CDCl3): d, ppm: aro-
matic protons, at 8.01–6.92 (m, 44H), In-OCOCH3 at 2.55 (s, 12H)
and alkyl protons on the coumarin group at 2.51 (s, 3H). Anal. Calc.
for C98H59InN8O14 (1687.38): C, 69.76; H, 3.52; N, 6.64. Found: C,
70.68; H, 3.57; N, 6.80%. MS (MALDI-TOF) m/z: 1627.46 [M-
acetate]+.
Yield: 0.14 g (26%). Mp >300 °C. UV–Vis kmax (nm) (log
e) (DMF):
317 (4.86), 620 (4.04), 683 (4.86). FT-IR [(KBr)
m
max/cmꢀ1]: 3063
(Ar–CH), 2920–2851 (CH), 1713 (C@O, lactone), 1678–1600
(C@C), 1278 (Ar–O–Ar). 1H NMR (CDCl3): d, ppm: aromatic protons,
at 7.98–6.76 (m, 72H), In-OCOCH3 at 2.59 (s, 24H) and alkyl protons
on the coumarin group at 2.12 (s, 3H). Anal. Calc. for C162H99InN8O26
(2688.38): C, 73.09; H, 3.68; N, 4.26. Found: C, 72.95; H, 3.74; N,
4.41%. MS (MALDI-TOF) m/z: 2628.55 [M-acetate]+.
3.5.6. 2(3),9(10),16(17),23(24)-Tetrakis(3-methyl-2-oxo-4-phenyl-
2H-chromen-7-yloxy)phthalocyaninato indium(III) acetate (10,
Scheme 1)
The compound 6 (0.5 g, 1.32 mmol), anhydrous indium(III)ace-
tate (0.19 g, 0.65 mmol) and dried N,N-dimethylaminoethanol
(2 mL) were refluxed with stirring under argon atmosphere for
24 h. After cooling to room temperature, the solution was dropped
in the hot methanol and then filtered off. The green solid product
was precipitated and collected by filtration and washed with sev-
eral times with hot methanol, ethanol, ethyl acetate, acetonitrile,
acetone, diethyl ether and dried. The green product was purified
by passing through a silica gel column using chloroform as the
eluting solvent. The compound 10 is soluble in chloroform, dichlo-
romethane, tetrahydrofurane, dimethylformamide and dimethyl-
sulfoxide. Yield: 0.16 g (29%). Mp >300 °C. UV–Vis kmax (nm)
4. Conclusions
In the presented work, the syntheses of new non-peripherally
tetra-(9), peripherally tetra-(10), peripherally chloro octa-(11)
and peripherally octa-(12) 7-oxy-3-methyl-4-phenylcoumarin-
substituted indium(III) phthalocyanine complexes were described
and new compounds were characterized by standard methods
(elemental analysis, 1H NMR, MALDI-TOF, IR, UV–Vis and fluores-
cence spectral data). The photophysical and photochemical proper-
ties of these indium(III) Pc complexes were also described in DMF
for comparison of the effects of the number of the substituents and
their position on the phthalocyanine framework. All the studied in-
dium(III) Pc complexes are soluble in general organic solvents
(such as chloroform, dichloromethane, THF, DMF and DMSO). In
solution, the absorption spectra of the studied indium(III) com-
plexes showed monomeric behavior evidenced by a single (nar-
row) Q band, typical of metallated phthalocyanine complexes in
DMF. All indium(III) Pc complexes (9–12) showed similar fluores-
cence behavior in DMF. The excitation spectra of these complexes
were similar to absorption spectra and both were mirror images of
the fluorescent spectra. Although, the fluorescence quantum yield
of the complexes 9, 10 and 11 are typical for indium(III) Pc com-
plexes, the fluorescence quantum yield of the chloro octa-substi-
tuted complex (11) is higher than indium(III) Pc complexes due
to due to the heavy atom effect of the chlorine atom. The 7-oxy-
3-methyl-4-phenylcoumarin-substituted indium(III) Pc complexes
(9–12) have good singlet oxygen quantum yields (UD), especially
non-peripherally tetra-substituted complex (9) results in the high-
est value. Heavy chlorine atom on the Pc ring decreased the UD va-
lue for complex 11 in DMF. The value of UD ranged from 0.30 to
0.83 gives an indication of the potential of the compounds as
photosensitizers in applications where singlet oxygen is required
such as Type II mechanism. The studied 7-oxy-3-methyl-4-phenyl-
coumarin-substituted indium(III) Pc complexes (9–12) show simi-
lar Ud values and stabilities to the indium(III) Pc complexes
applicable in PDT.
(log
m
e) (DMF): 320 (4.52), 618 (3.98), 687 (4.68). FT-IR [(KBr)
max/cmꢀ1]: 3059 (Ar–CH), 2922–2852 (CH), 1714 (C@O, lactone),
1656 (C@C), 1601(C@C), 1237 (Ar–O–Ar). 1H NMR (CDCl3): d,
ppm: aromatic protons, at 8.25–6.72 (m, 44H), In-OCOCH3 (s, 3H)
at 2.81 and alkyl protons on the coumarin group at 2.51 (s, 12H).
Anal. Calc. for C98H59InN8O14 (1687.38): C, 69.76; H, 3.52; N, 6.64.
Found: C, 70.67; H, 3.55; N, 6.79%. MS (MALDI-TOF) m/z: 1627.50
[M-acetate]+.
3.5.7. Octakis{[2,9,16,23-(3-methyl-2-oxo-4-phenyl-2H-chromen-7-
yloxy)3,10,17,24-chloro]}phthalocyaninato indium(III) acetate (11,
Scheme 1)
The compound 7 (0.5 g, 1.21 mmol), anhydrous indium(III)ace-
tate (0.19 g, 0.65 mmol) and dried N,N-dimethylaminoethanol
(2 mL) were refluxed with stirring under argon atmosphere for
24 h. After cooling to room temperature, the solution was dropped
in the hot methanol and then filtered off. The green solid product
was precipitated and collected by filtration and washed several
times with hot methanol, ethanol, ethyl acetate, acetonitrile, ace-
tone, diethyl ether and dried. The green product was purified by
passing through a silica gel column, using chloroform as the elut-
ing solvent. The compound 11 is soluble in chloroform, dichloro-
methane,
dimethylsulfoxide. Yield: 0.15 g (27%). Mp >300 °C. UV–Vis kmax
(nm) (log ) (DMF): 317 (4.38), 615 (3.86), 677 (4.30). FT-IR
[(KBr)
tetrahydrofurane,
dimethylformamide
and
e
m
max/cmꢀ1]: 3075 (Ar–CH), 2919–2850 (CH), 1717 (C@O, lac-
tone), 1602 (C@C), 1433 (C@C), 1273 (Ar–O–Ar). 1H NMR (CDCl3):
d, ppm: aromatic protons, at 7.91–6.98 (m, 40H), In-OCOCH3 at
2.60 (s, 3H) and alkyl protons at 2.54 (s, 12H). Anal. Calc. for
Acknowledgements
C
98H55Cl4InN8O14 (1825.16): C, 64.49; H, 3.04; N, 6.29. Found: C,
We are thankful to the Research Foundation of Marmara
University, Commission of Scientific Research Project (BAPKO)
[FEN-C-DRP-110908-0232 and FEN-A-090909-0302].
65.13; H, 2.98; N, 6.43%. MS (MALDI-TOF) m/z: 1766.15 [M-
acetate]+.

116
M. Pißskin et al. / Inorganica Chimica Acta 373 (2011) 107–116
(b) Y. Chen, M. Hanack, Y. Araki, O. Ito, Chem. Soc. Rev. 34 (2005) 517;
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