Synthesis, photophysical and photochemical properties of novel tetra substituted metal free and metallophthalocyanines bearing triazine units

Article abstract of DOI:10.1016/j.jorganchem.2012.11.001

The synthesis and characterization of peripherally tetra 2-(4,6-diphenyl-1,3,5-triazine-2-yl)-5-(hexyloxy)phenoxy substituted metal-free (4), zinc(II) (5), oxotitanium(IV) (6), lead(II) (7), nickel(II) (8), copper(II) (9) and cobalt(II) (10) were describe

Full text of DOI:10.1016/j.jorganchem.2012.11.001

Journal of Organometallic Chemistry 724 (2013) 225e234
Contents lists available at SciVerse ScienceDirect
Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
Synthesis, photophysical and photochemical properties of novel tetra substituted
metal free and metallophthalocyanines bearing triazine units
a
c
Ümit Demirbas¸ , Rıza Bayrak a, Mehmet Pis¸ kin b, Hakkı Türker Akçaya, Mahmut Durmus¸ ,
Halit Kantekin a
,
*
a Department of Chemistry, Faculty of Sciences, Karadeniz Technical University, 61080 Trabzon, Turkey
b Marmara University, Faculty of Art and Science, Department of Chemistry, 34722 Kadikoy, Istanbul, Turkey
c Gebze Institute of Technology, Department of Chemistry, P.O. Box 141, 41400 Gebze, 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 and characterization of peripherally tetra 2-(4,6-diphenyl-1,3,5-triazine-2-yl)-5-(hexyloxy)
phenoxy substituted metal-free (4), zinc(II) (5), oxotitanium(IV) (6), lead(II) (7), nickel(II) (8), copper(II)
(9) and cobalt(II) (10) were described for the first time in this study. The photophysical and photo-
chemical properties of metal-free (4), zinc(II) (5), oxotitanium(IV) (6) and lead(II) (7) phthalocyanines
were investigated in toluene. The synthesized nickel(II) (8), copper(II) (9) and cobalt(II) (10) phthalo-
cyanines were not evaluated for this purpose because of paramagnetic behavior of the central transition
metals in the cavity for these complexes. General trends were described for photodegradation, singlet
oxygen and fluorescence quantum yields, and fluorescence lifetimes of these compounds in toluene. The
influence of the variety of central metal ions in phthalocyanine cavity on the spectroscopic, photo-
physical and photochemical properties were also determined. The fluorescence quenching behavior of
the studied peripherally tetra 2-(4,6-diphenyl-1,3,5-triazine-2-yl)-5-(hexyloxy)phenoxy substituted
metal-free (4), zinc(II) (5), oxotitanium(IV) (6) and lead(II) (7) by the addition of 1,4-benzoquinone were
also studied.
Received 23 July 2012
Received in revised form
30 October 2012
Accepted 2 November 2012
Keywords:
Phthalocyanine
Triazine
Photophysical
Photochemical
Singlet oxygen
Ó 2012 Elsevier B.V. All rights reserved.
1. Introduction
phthalocyanines. This interaction results in aggregation that
decreases solubility of Pcs and causes low-broad electronic
After accidental preparation of phthalocyanine (Pc) by Braun
and Tcherniac in 1907, people used Pc molecules as dyes and
pigments [1]. At the present day, Pcs are utilized in various scien-
tific and technological areas from electronics [1] to medicine [2],
thus scientists endeavor to synthesize new compounds that have
purposive properties. Pcs have many technological applications in
different scientific areas such as chemical sensors [3e5], electro-
chromic displaying systems [6], non-linear optics [7], solar cells [8],
molecular electronics [9], semiconductors [10], liquid crystals [11],
optical storage devices [12], laser dyes [13], catalyst [14] and
photodynamic therapy (PDT) [15].
absorption band in UVevis spectrum. The aggregation tendency of
phthalocyanines in solution also decreases the photosensing
ability. Axially and bulky peripheral/non-peripheral substitution
can hinder
pep stacking between planar macrocycle rings of Pcs
and decrease aggregation [17,18].
The aim of this research was to produce new soluble and non-
aggregated Pc compounds and to investigate their photophysical
and photochemical properties. The investigation of photophysical
and photochemical properties is worthy for usability of compounds
as photocatalytic applications such as photodynamic therapy (PDT)
of cancer. To the best of our knowledge, there have been a few
literature containing triazine bearing Pcs, but their photophysical
and photochemical properties have not been investigated, so
triazine group was chosen as peripheral substituent on the
phthalocyanine [19,20].
The solubility of phthalocyanines is very important for their
efficiency in their field of application. The solubility of Pcs may be
enhanced by nature of the substituent and/or central metal ion [16].
In addition intermolecular interaction of the Pc macrocycles is
a
crowning problem for the technological application of
In this study, the syntheses of metal free (4), Zn(II) (5), Ti(IV) (6),
Pb(II) (7), Ni(II) (8), Cu(II) (9) and Co(II) (10) phthalocyanine
compounds which are tetra-substituted with 2-(4,6-diphenyl-
1,3,5-triazine-2-yl)-5-(hexyloxy)phenoxy groups. The character-
ization, aggregation behavior, photophysical and photochemical
* Corresponding author. Tel.: þ90 462 377 25 25; fax: þ90 462 325 31 96.
E-mail address: halit@ktu.edu.tr (H. Kantekin).
0022-328X/$ e see front matter Ó 2012 Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.jorganchem.2012.11.001

226
Ü. Demirbas¸ et al. / Journal of Organometallic Chemistry 724 (2013) 225e234
properties of new compounds have been investigated and the
2.4. Photochemical parameters
results were reported for the first time.
2.4.1. Singlet oxygen quantum yields
Singlet-oxygen quantum yield
(FD) determinations were
2. Experimental
carried out using the experimental setup described in the literature
[26e28]. Typically, a 2 mL portion of the respective Pc compounds
bearing triazine groups (4e7) solutions (absorbance ca. 1.8 at the
irradiation wavelength) that contained the singlet oxygen scav-
enger was irradiated in the Q-band region with the photo irradia-
tion setup described in the literature. The FD values were
determined in air using the relative method with DPBF as a singlet
oxygen chemical scavenger in toluene using Equation (3)
2.1. Materials
All reactions were carried out under dry and oxygen-free
nitrogen atmosphere using standard Schlenk techniques. 1,3-
diphenylisobenzofuran (DPBF) and 1,8-diazabycyclo[5.4.0]undec-
7-ene (DBU) were purchased from Fluka. 2-(4,6-diphenyl-1,3,5-
triazin-2-yl)-5-(hexyloxy)phenol (1) and unsubstituted ZnPc
were purchased from Aldrich. All solvents were dried and
purified as described by Perrin and Armarego [21] before use. 4-
Nitrophthalonitrile (2) [22] was prepared according to the literature.
Std
R$I
FSDtd
(3)
abs
FD
¼
RStd$Iabs
FSDtd is the singlet oxygen quantum yield for the standard
2.2. Equipment
unsubstituted ZnPc (FDStd ¼ 0:58 in toluene) [29]. R and RStd are the
DPBF photobleaching rates in the presence of the respective Pc
compounds bearing triazine groups (4e7) and standard, respec-
tively; Iabs and IStd are the rates of light absorption by the samples
(4e7) and standaabrsd, respectively. The concentrations of DPBF in the
solutions were calculated using the determined value of
1H NMR and 13C NMR (for phthalonitrile compound) spectra
were recorded on a Varian XL-200 NMR spectrophotometer in
CDCl3, and chemical shifts were reported (d) relative to Me4Si as
internal standard. FT-IR spectra were recorded on a PerkineElmer
Spectrum one FT-IR spectrometer in KBr pellets. The mass spectra
were measured with a Micromass Quattro LC/ULTIMA LC-MS/MS
spectrometer using chloroformemethanol as solvent system. All
experiments were performed in the positive ion mode. Elemental
analyses were performed on a Costech ECS 4010 instrument; the
obtained values agreed with the calculated ones. Melting points
were measured on an electrothermal apparatus and are uncor-
rected. Absorption spectra in the UVevisible region were recorded
with a Shimadzu 2101 UVevis spectrophotometer. Fluorescence
excitation and emission spectra were recorded on a Varian Eclipse
spectrofluorometer using 1 cm path length cuvette at room
temperature. General Electric quartz line lamp (300 W) was used
for photo-irradiations studies. A 600 nm glass cut off filter (Intor)
and a water filter were used to filter off ultraviolet and infrared
radiations, respectively. An interference filter (Intor, 670 nm for
compounds 4e6 and 700 nm for compound 7 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 (Mole-
lectron detector incorporated) power meter.
log
3
¼ 4.36 at 417 nm (DPBF in toluene). The light intensity used for
FD determinations was found to be 6.60 ꢀ 1015 photons sꢁ1 cmꢁ2
.
2.4.2. Photodegradation quantum yields
Photodegradation quantum yield (Fd) determinations were
carried out using the experimental set-up described in literature
[26e28]. Photodegradation quantum yields were determined using
Equation (4),
ðC0 ꢁ CtÞ$V$NA
Fd
¼
(4)
I
abs$S$t
where C0 and Ct are the samples (4e7) 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 (4e7). A light
intensity of 2.15 ꢀ 1016 photons sꢁ1 cmꢁ2 was employed for Fd
determinations.
2.3. Photophysical parameters
2.4.3. Fluorescence quenching studies by 1,4-benzoquinone (BQ)
Fluorescence quenching experiments on the tetra-2-(4,6-
diphenyl-1,3,5-triazine-2-yl)-5-(hexyloxy)phenoxy substituted Pc
compounds (4e7) were carried out by the addition of different
concentrations of BQ to a fixed concentration of the compounds,
and the concentrations of BQ in the resulting mixtures were 0,
0.008, 0.016, 0.024 and 0.032 M. The fluorescence spectra of the
tetra substituted Pc compounds (4e7) at each BQ concentration
were recorded, and the changes in fluorescence intensity related to
BQ concentration by the SterneVolmer (SV) equation [30]
(eqn (5)):
2.3.1. Fluorescence quantum yields and lifetimes
Fluorescence quantum yields (FF) of studied phthalocyanine
compounds (4e7) were determined by the comparative method
using Equation (1) [23],
F$AStd$n2
FF
¼
FFðStdÞ
(1)
F
Std$A$n2Std
where F and FStd are the areas under the fluorescence emission
curves of the samples (4e7) and the standard, respectively. A and
AStd are the respective absorbances (which was w0.05) of the
samples and standard at the excitation wavelengths and n and nstd
are the refractive indices of solvents used for the sample and
standard, respectively. Unsubstituted ZnPc (FF ¼ 0.07) [24] was
employed as the standard in toluene.
I0
I
¼ 1 þ KSV½BQꢂ
(5)
I0 and I are the fluorescence intensities of fluorophore in the
absence and presence of quencher, respectively. [BQ] is the
concentration of the quencher and KSV is the SterneVolmer
constant; and this is the product of the bimolecular quenching
Natural radiative lifetimes (
chemCAD program which uses the StricklereBerg equation [25].
s0) were determined using Photo-
The fluorescence lifetimes (
s
F) were evaluated using Equation (2).
(2)
constant (kq) and the fluorescence lifetime
sF (Equation (6)):
sF
FF
¼
KSV ¼ kqsF
(6)
s0

Ü. Demirbas¸ et al. / Journal of Organometallic Chemistry 724 (2013) 225e234
227
The ratios I0/I were calculated and plotted against [BQ] accord-
ing to Equation (5), and KSV determined from the slope.
1H NMR (CDCl3), (
d: ppm): 8.54e8.35 (m 20H/AreH), 7.68e7.34
(m, 20H/AreH), 7.14e7.09 (m, 24H/AreH), 4.03e4.01 (t, 8H/OCH2),
1.74e1.72 (m, 8H/OCH2CH2), 1.39e1.27 (m, 24H/CH2), 0.93e0.88
2.5. Synthesis
(t, 12H/CH3). UVevis (Chloroform): lmax/nm (log ): 685 (5.13), 615
3
(4.40), 345 (4.85). MS (ESI), (m/z): Calculated: 2269.86; Found:
2.5.1. 4-(2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-(hexyloxy)phenoxy)
phthalonitrile (3)
2270.51 [M þ H]þ.
To a solution of 4-nitrophthalonitrile (2) (0.4069 g, 2.35 mmol)
in dry DMF (20 cm3) compound 1 (1 g, 2.35 mmol) was added and
the temperature was increased up to 55 ꢃC. Finely powdered dry
K2CO3 (0.3243 g, 2.35 mmol) was added to the reaction in eight
equal portions at 15 min intervals with efficient stirring and the
reaction was stirred at the same temperature for 5 days. The
reaction mixture was poured into ice-water. The precipitate was
filtered and dried in vacuum over P2O5 and recrystallized from
ethanol to give light yellow crystalline powder. Yield: 0.7 g, (54%),
mp: 151e153 ꢃC. Anal. Calc. for C35H29N5O2: C, 76.20; H, 5.30; N,
2.5.2.3. Oxotitanium (IV) phthalocyanine (6). Solvent system for
column chromatography: Chloroform:methanol (100:5). Yield:
50 mg, (24%), mp: >300 ꢃC (decomposition). Anal. Calc. for
C
140H116N20O9Ti: C, 74.06; H, 5.15; N,12.34; Found: C, 74.17; H, 5.03;
N, 12.45. FT-IR (KBr tablet) ymax/cmꢁ1: 3067
(AreCH), 2922e2857
(aliph. CH), 1617e1561 (C]C), 1525 (AreC]N), 1369e1245
(CH), 1027 : ppm): 8.47e8.32 (m
(CeOeC). 1H NMR (CDCl3), (
y
y
y
y
d
y
d
20H/AreH), 7.64e7.22 (bm, 20H/AreH), 7.10e7.09 (m, 24H/AreH),
4.03e3.95 (bt, 8H/OCH2), 1.66e1.54 (bm, 8H/OCH2CH2), 1.33e1.22
(m, 24H/CH2), 0.89e0.77 (bt, 12H/CH3). UVevis (Chloroform):
12.70, Found: C, 76.17; H, 5.26; N, 12.74. FT-IR (KBr tablet) ymax
cmꢁ1: 3067
(AreCH), 2928e2855 (aliph. CH), 2231 (C^N), 1613e
1567 (C]C), 1519 (AreC]N), 1365e1243 (CH), 1026 (CeOeC).
1H NMR (CDCl3), (
/
lmax/nm (log ): 710 (5.16), 684 (4.83), 645 (4.58), 346 (5.31). MS
3
y
y
(ESI), (m/z): Calculated: 2269.88; Found: 2270.85 [M þ H]þ.
y
y
d
y
d
: ppm): 8.55e8.51 (d, J ¼ 7.81 Hz, 2H/AreH),
2.5.2.4. Lead (II) phthalocyanine (7). Solvent system for column
chromatography: Chloroform:methanol (100:6). Yield: 80 mg, (39%),
mp: >300 ꢃC (decomposition). Anal. Calc. for C140H116N20O8Pb: C,
69.66; H, 4.84; N, 11.61; Found: C, 69.58; H, 4.73; N, 11.52. FT-IR (KBr
8.33e8.30 (d, J ¼ 6.64 Hz, 2H/AreH), 7.73e7.08 (m, 9H/AreH),
6.68 (s, 1H/AreH), 6.60e6.50 (t, J ¼ 7.88 Hz, 2H/ArH), 4.04e4.01
(t, J ¼ 6.21 Hz, 2H/OCH2), 1.79e1.82 (m, 2H/OCH2CH2), 1.35e1.40
(m, 6H/CH2), 0.95e0.91 (t, J ¼ 6.77 Hz, 3H/CH3). 13C NMR (CDCl3),
tablet) ymax/cmꢁ1: 3072
1562 (C]C), 1525 (AreC]N), 1372e1243
1H NMR (CDCl3), (
: ppm): 8.45e8.41 (m 20H/AreH), 7.84e7.77 (m,
y(AreCH), 2921e2863
y(aliph. CH), 1615e
(d
: ppm): 171.61, 164.21, 163.83, 163.18, 153.61, 135.98, 135.52,
y
y
d(CH), 1032
y(CeOeC).
134.71, 132.98, 128.93, 128.81, 122.62, 121.56, 121.06, 117.68, 115.28,
113.67, 109.51, 108.84, 69.08, 31.82, 29.28, 25.93, 22.87, 14.35. MS
(ESI), (m/z): Calculated: 551.23; Found: 552.35 [M þ H]þ.
d
20H/AreH), 7.20e7.12 (m, 24H/AreH), 4.07e3.94 (bt, 8H/OCH2),
1.79e1.68 (m, 8H/OCH2CH2), 1.27e1.21 (m, 24H/CH2), 0.91e0.88 (bt,
12H/CH3). UVevis (Chloroform): lmax/nm (log ): 726 (5.15), 651
3
2.5.2. General procedure for synthesis of metal free (4) and
metallophthalocyanines (5e10)
(4.54), 391 (4.76), 366 (4.78). MS (ESI), (m/z): Calculated: 2413.91;
Found: 2414.84 [M þ H]þ.
In a glass sealed tube, the mixture of compound (3) (0.20 g,
0.363 mmol), for metallophthalocyanines related metal salts
[(Zn(Ac)2 (17 mg, 0.091 mmol); Ti(OBu)4 (0.04 cm3, 0.812 mmol);
PbO (20 mg, 0.091 mmol); NiCl2 (12 mg, 0.091 mmol); CuCl2
(12 mg, 0.091 mmol); CoCl2 (12 mg, 0.091 mmol)] in dry n-pentanol
(3 cm3) were heated to 90 ꢃC and 3 drops of 1,8-diazabycyclo[5.4.0]
undec-7-ene (DBU) was added and the temperature was increased
to 160 ꢃC for 24 h. Then they were precipitated by ethanol and then
filtered. After washing with hot water, ethanol, acetone and diethyl
ether the pure phthalocyanines (4e10) were isolated through silica
gel column for removing impurities. The chemical and physical
spectral characteristics of these products are given below.
2.5.2.5. Nickel(II) phthalocyanine (8). Solvent system for column
chromatography: Chloroform:methanol (100:5). Yield: 90 mg, (44%),
mp: >300 ꢃC (decomposition). Anal. Calc. for C140H116N20O8Ni: C,
74.23; H, 5.16; N, 12.37; Found: C, 74.33; H, 5.06; N, 12.49. FT-IR (KBr
tablet) ymax/cmꢁ1: 3071
1561 (C]C), 1522 (AreC]N), 1372e1243
1H NMR (CDCl3), (
: ppm): 8.50e8.44 (m 20H/AreH), 7.82e7.66
y
(AreCH), 2921e2863
y
(aliph. CH), 1615e
(CeOeC).
y
y
d(CH), 1031
y
d
(bm, 20H/AreH), 7.19e7.13 (m, 24H/AreH), 4.02e3.91 (bt, 8H/
OCH2), 1.69e1.64 (m, 8H/OCH2CH2), 1.39e1.11 (bm, 24H/CH2), 0.91e
0.87 (t, 12H/CH3). UVevis (Chloroform): lmax/nm (log ): 677 (5.13),
3
650 (4.72), 609 (4.53), 381 (5.10). MS (ESI), (m/z): Calculated:
2263.87; Found: 2264.52 [M þ H]þ.
2.5.2.1. Metal free phthalocyanine (4). Solvent system for column
chromatography: Chloroform. Yield: 70 mg, (35%), mp: >300 ꢃC
(decomposition). Anal. Calc. for C140H118N20O8: C, 76.14; H, 5.39; N,
2.5.2.6. Copper(II) phthalocyanine (9). Solvent system for
column chromatography: Chloroform:methanol (100:5). Yield:
100 mg, (50%), mp: >300 ꢃC (decomposition). Anal. Calc. for
12.68. Found: C, 76.25; H, 5.48; N, 12.61. FT-IR (KBr tablet) ymax
/
cmꢁ1: 3292 (eNH) 3065
1566 (C]C), 1519 (AreC]N), 1365e1243
1H NMR (CDCl3), (
y(AreCH), 2925e2857
y(aliph. CH), 1611e
C
140H116N20O8Cu: C, 74.07; H, 5.15; N, 12.34; Found: C, 74.15; H,
5.03; N, 12.43. FT-IR (KBr tablet) ymax/cmꢁ1: 3070
(AreCH),
(AreC]N),
(CeOeC). UVevis (Chloroform): lmax
y
y
d
(CH), 1027
y
(CeOeC).
y
d
: ppm): 8.40e8.44 (m 20H/AreH), 7.75e7.45
2922e2864
1370e1241
y
(aliph. CH), 1614e1560
y(C]C), 1519 y
(m, 10H/AreH), 7.28e7.15 (m, 34H/AreH), 4.03e3.98 (t, 8H/
OCH2), 1.74e1.71 (m, 8H/OCH2CH2), 1.30e0.93 (m, 24H/CH2),
0.67e0.65 (t, 12H/CH3), ꢁ3.51 (s, 2H/eNH). UVevis (Chloroform):
d
(CH), 1035
y
/
nm (log ): 686 (5.12), 618 (4.52), 354 (4.84). MS (ESI), (m/z):
3
Calculated: 2268.86; Found: 2269.54 [M þ H]þ.
lmax/nm (log ): 707 (5.08), 671 (5.01), 641 (4.57), 609 (4.36), 344
3
(4.81). MS (ESI), (m/z): Calculated: 2207.95; Found: 2208.42
2.5.2.7. Cobalt(II) phthalocyanine (10). Solvent system for column
chromatography: Chloroform:methanol (100:4). Yield: 88 mg, (43%),
mp: >300 ꢃC (decomposition). Anal. Calc. for C140H116N20O8Co: C,
74.22; H, 5.16; N, 12.37; Found: C, 74.17; H, 5.21; N, 12.26. FT-IR (KBr
[M þ H]þ.
2.5.2.2. Zinc (II) phthalocyanine (5). Solvent system for column
chromatography: Chloroform:methanol (100:7). Yield: 80 mg, (39%),
mp: >300 ꢃC (decomposition). Anal. Calc. for C140H116N20O8Zn: C,
74.01; H, 5.15; N, 12.33; Found: C, 73.94; H, 5.25; N, 12.40. FT-IR (KBr
tablet) ymax/cmꢁ1: 3071
1560 (C]C), 1521 (AreC]N), 1370e1241
UVevis (Chloroform): lmax/nm (log ): 678 (5.12), 618 (4.59), 387
y(AreCH), 2920e2863
y(aliph. CH), 1615e
y
y
d(CH), 1030
y(CeOeC).
3
tablet) ymax/cmꢁ1: 3066
1564 (C]C), 1522 (AreC]N), 1371e1245
y
(AreCH), 2924e2858
y
(aliph. CH), 1614e
(CeOeC).
(4.46). MS (ESI), (m/z): Calculated: 2264.86; Found: 2287.44
y
y
d(CH), 1033 y
[M þ Na]þ.

228
Ü. Demirbas¸ et al. / Journal of Organometallic Chemistry 724 (2013) 225e234
Fig. 1. Synthetic route of new phthalocyanine compounds.
3. Results and discussion
shielded inner core eNH protons was observed at ꢁ3.51 ppm which
was proof of the formation of the metal free Pc. The rest of the
spectrum was not very different than that of the phthalonitrile
derivative (3). The 1H NMR spectra of the MPcs 5, 6, 7 and 8 were
not very different than that of the compound 3 except the broad-
ness of the signals because of probable aggregation at the
concentration for NMR measurements. In the mass spectra of
compounds 4e10, the parent molecular ion peaks were observed at
m/z ¼ 2208.42 [M þ H]þ for 4, 2270.51 [M þ H]þ for 5, 2270.85
[M þ H]þ for 6, 2414.84 [M þ H]þ for 7, 2264.52 [M]þ for 8, 2269.54
[M þ H]þ for 9 and 2287.44 [M þ Na]þ for 10, these peaks have
verified the proposed structures.
3.1. Synthesis and characterization
The synthesis route of 4-(2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-
(hexyloxy) phenoxy)-phthalonitrile (3) and its peripherally tetra-
substituted metal free (4) and metallophthalocyanine (5, 6, 7, 8, 9
and 10) derivatives is shown in Fig. 1. The structures of new
compounds have been characterized by a combination of 1H and
13C NMR (for phthalonitrile compound), FT-IR, UVevis spectros-
copy, elemental analysis and mass spectral data.
Most commonly, phthalonitriles or 1,3-diimino-1H-isoindoles
are used by chemists to prepare phthalocyanines by cyclo-
tetramerization and nucleophilic aromatic nitro substitution reac-
tion of 4-nitrophthalonitrile have been succeeded by many
researchers [31,32], In this context, phthalonitrile derivative (3) was
prepared from the reaction of 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-
5-(hexyloxy)phenol (1) with 4-nitrophthalonitrile (2) in the pres-
ence of anhydrous K2CO3 as a base under N2 atmosphere at 60 ꢃC in
Schlenk system for 5 days in dry DMF. In the FT-IR spectrum of this
compound, the absence of eOH stretching/deformation of
compound 1 and the presence of C^N absorption band at
2231 cmꢁ1 clearly proves the formation of compound 3. In the 1H
NMR spectrum of 3, OH group of compound 1 disappeared as ex-
pected. In the mass spectrum of compound 3, the presence of
molecular ion peaks at m/z ¼ 552.35 [M þ H]þ, confirmed the
proposed structures.
3.2. UVevis absorption spectra
UVevis spectroscopy is one of the best evidences for the
determination of the phthalocyanines. In general, phthalocyanines
have two strong absorptions in the UVevis regions. One around ca.
300 nm is called as the ‘‘B’’ or “Soret” band due to electronic
transitions from deeper
other one at 600e750 nm is called as the ‘‘Q’’ band, due to transi-
tions from -HOMO to *-LUMO energy levels. While the Q bands
p-HOMO to n*-LUMO energy levels and the
p
p
of the metal-free phthalocyanines were observed as splitted two
The metal free (3) and metallophthalocyanine complexes (5e10)
were prepared by cyclotetramerization of the substituted phtha-
lonitrile (3) and corresponding metal salts in the presence of DBU
by heating under reflux temperature for 24 h in n-pentanol. The
newly synthesized phthalocyanine compounds were characterized
1H NMR, FT-IR, elemental analysis, UV/vis and mass spectral
investigations, and the results are in accordance with the proposed
structures. Cyclotetramerization of the substituted phthalonitrile
(3) to Pcs 4, 5, 6, 7, 8, 9 and 10 was confirmed by the disappearance
of the sharp C^N vibration at 2231 cmꢁ1 in their FT-IR spectra.
The inner core eNH vibration was observed at 3292 cmꢁ1 for the
metal free derivative (4) different from other studied metal-
lophthalocyanines (5e7). The rest of the spectra of Pcs were similar
to that of 3. The 1H NMR spectra of 9 and 10 could not be deter-
mined because of the presence of paramagnetic cobalt and copper
atoms [33]. In the 1H NMR spectrum of the metal free Pc (4)
Fig. 2. Absorption spectra of compounds 4, 5 and 6 in CHCl3 at 1 ꢀ 10ꢁ5 M.

Ü. Demirbas¸ et al. / Journal of Organometallic Chemistry 724 (2013) 225e234
229
is dependent on the concentration, nature of the solvent, nature of
the substituents, compound’s metal ions and temperature [34,35].
The aggregation behavior of the studied phthalocyanine
compounds (4e7) was studied at different concentration in
toluene. In toluene, as the concentration was increased, the inten-
sity of absorption of the Q band also increased and there were no
new bands (normally blue shifted) due to the aggregated species
for the compounds (4e7). The BeereLambert law was obeyed for all
of these complexes at concentrations ranging from 1.6 ꢀ 10ꢁ5 to
4 ꢀ 10ꢁ6 M.
3.3. Fluorescence spectra
The shapes of the excitation spectra were similar to absorption
spectra for the metal-free (4) zinc phthalocyanine (5) and titanium
(6) compounds (Fig. 5(A), (B), and (C)) suggesting that the nuclear
configurations of the ground and excited states are similar and not
affected by excitation for these compounds. For the lead phthalo-
cyanine complex (7), the shape of excitation spectra was different
from the absorption spectra in that the Q band of the former
showed two peaks in the Q band region, Fig. 5(D), unlike the
narrow Q band of the latter. This suggests that there are changes in
the molecule following excitation most likely due to the larger lead
metal being out of the plane of the phthalocyanine ring.
Fig. 3. Absorption spectra of compounds 7, 8, 9 and 10 in CHCl3 at 1 ꢀ 10ꢁ5 M.
bands due to D2h symmetry, as Qx and Qy bands, that of metal-
lophthalocyanines were observed as a single band due to D4h
symmetry [31].
The electronic absorption spectrum of compound 4 in chloro-
form solution at room temperature is shown in Fig. 2. The splitting
Q band was observed at lmax 707 and 671 nm, indicating the
structure with non-degenerate D2h symmetry. The electronic
spectra of the metallophthalocyanine compounds (5e10) showed
characteristic absorption in the Q band region at around 677e
726 nm in chloroform (Figs. 2 and 3). The B bands were observed
at around 339e387 nm (Figs. 2 and 3). The spectra showed
monomeric behavior for studied Pc complexes evidenced by
narrow (sharp) Q bands, typical of phthalocyanines. The Q band of
the lead(II) phthalocyanine complex (7) was red-shifted when
compared to the corresponding other studied phthalocyanine
complexes in chloroform (Fig. 3), suggesting that the non-planar
effect of the bigger lead as central atom. The electronic absorp-
tion spectra of studied phthalocyanine complexes in toluene were
also given in Fig. 4.
Fluorescence emission and excitation peaks of studied
compounds (4e7) in toluene were listed in Table 1. The observed
Stokes shifts of the studied phthalocyanine compounds (4e7) are
lower than unsubstituted zinc Pc in toluene (Table 1).
3.4. Fluorescence quantum yields and lifetimes
The fluorescence quantum yields (FF) of the tetra 2-(4,6-
diphenyl-1,3,5-triazine-2-yl)-5-(hexyloxy)phenoxy
substituted
phthalocyanine compounds (5e7) were studied in toluene. The
fluorescence quantum yields (FF) of the studied tetra triazine
substituted Pc compounds (4e7) are given in Table 2. The FF values
of studied phthalocyanine complexes are higher than unsub-
stituted zinc Pc especially FF values of metal-free (4) and lead (II)
Aggregation is usually depicted as a coplanar association of rings
progressing from monomer to dimer and higher order complexes. It
2
1.8
1.6
1.4
1.2
1
4
5
6
7
0.8
0.6
0.4
0.2
0
300
350
400
450
500
550
600
650
700
750
800
Wavelength (nm)
Fig. 4. Absorption spectra of the studied tetra-substituted metal-free (4), zinc(II) (5), oxotitanium(IV) (6) and lead(II) (7) phthalocyanine compounds in toluene.
Concentration ¼ 1 ꢀ 10ꢁ5 M.

230
Ü. Demirbas¸ et al. / Journal of Organometallic Chemistry 724 (2013) 225e234
Fig. 5. Absorption, excitation and emission spectra of the studied tetra-substituted metal-free (4), zinc(II) (5), oxotitanium(IV) (6) and lead(II) (7) phthalocyanine compounds in
toluene. Excitation wavelength ¼ 708 nm for (4), 687 nm for (5), 709 nm for (6) and 708 nm for (7).

Ü. Demirbas¸ et al. / Journal of Organometallic Chemistry 724 (2013) 225e234
231
Table 1
the increasing in the FF value for substituted phthalocyanine
complexes in the presence of the ring substituent suggests that
the substituents less quench the excited singlet state, hence the
fluorescence. The FF value of oxotitanium(IV) phthalocyanine
complex (6) is the lowest among the studied tetra substituted Pc
compounds. The lowest FF value for compound 6 could be due to
the little aggregation behavior of this compound in toluene. The FF
values of metal-free (4) and lead(II) (7) phthalocyanine complexes
look similar in toluene. It could be due to the larger lead metal ion
being out of the plane of the phthalocyanine ring turns into its
metal-free phthalocyanine during the excitation measurements.
Absorption, excitation and emission spectral data for the unsubstituted and the
tetra-2-(4,6-diphenyl-1,3,5-triazine-2-yl)-5-(hexyloxy)phenoxy substituted phtha-
locyanine compounds in toluene.
Compound Q band
lmax, (nm)
706; 670
log
3
Excitation Emission
lEx, (nm) lEm, (nm) DStokes, (nm)
5.20; 5.17 708
Stokes shift
4
5
6
7
712
693
712
710
e
4
684
704
717
676
685
677
672a
5. 24
4.92
5.01
5.24
5.21
5.20
5.14a
687
709
708
e
6
3
2
e
e
e
4b
8
9
10
ZnPc
e
e
e
e
676b
Fluorescence lifetime (sF) refers to the average time a molecule
672
stays in its excited state before fluorescing. Any factors can be effect
the fluorescence lifetime of a fluorophore such as internal conver-
sion and intersystem crossing. As a result, the nature and the
environment of a fluorophore determine its fluorescence lifetime.
a
Data from ref. [36].
Data from ref. [24].
b
Lifetimes of fluorescence (sF) were calculated using the Stricklere
Table 2
Photophysical and photochemical data of the unsubstituted and the tetra triazine
substituted phthalocyanine compounds in toluene.
Berg equation. Using this equation, a good correlation has been
found [23] for the experimentally and theoretically determined
fluorescence lifetimes for the unaggregated molecules, as is the
case in this work for the tetra-2-(4,6-diphenyl-1,3,5-triazine-2-yl)-
5-(hexyloxy)phenoxy substituted Pc compounds in toluene. Thus,
Compound FF
sF (ns)
s
0 (ns) kFa (sꢁ1) (ꢀ108) Fd (ꢀ10ꢁ3
)
FD
4
5
6
7
0.27
1.82
1.48
1.43
2.47
6.75
7.81
1.48
1.28
0.83
1.06
1.38
0.04
0.20
0.60
0.40
0.42
0.58b
0.19
0.12
0.26
11.97
9.44
4.80
we believe that the
sF values obtained using this equation is a good
23.30
measure of fluorescence lifetimes. Fluorescence lifetime (
s
F) values
ZnPcb
0.07b 0.90c
12.97c 7.70c
0.062d
of the tetra tetra-2-(4,6-diphenyl-1,3,5-triazine-2-yl)-5-(hexyloxy)
phenoxy substituted Pc compounds (4e7) are longer compared to
unsubstituted zinc(II) Pc compound in toluene, suggesting less
quenching by substitution. Thus, the substitution on the phthalo-
cyanine ring increased the sF values. The sF value of the oxotita-
nium(IV) phthalocyanine complex (6) is shorter than the other
studied tetra substituted Pc compounds due to the aggregation
behavior of this compound in toluene.
a
kF is the rate constant for fluorescence. Values calculated using kF
¼
FF/sF.
b
c
Ref [24].
Ref [37].
Ref [38].
d
(7) phthalocyanines are quite higher. An increase in fluorescence
intensity (hence yield) for studied complexes may occur in the
presence of 2-(4,6-diphenyl-1,3,5-triazine-2-yl)-5-(hexyloxy)phe-
noxy groups which decreasing of the fluorescence quenching. Thus
The natural radiative lifetime (
s0) and the rate constants for
fluorescence (kF) values in toluene are also given in Table 2. The s0
Fig. 6. Absorption changes during the determination of singlet oxygen quantum yield. This determination was for the zinc phthalocyanine complex (5) in toluene at a concentration
of 1 ꢀ 10ꢁ5 M (Inset: Plot of DPBF absorbance versus time).

232
Ü. Demirbas¸ et al. / Journal of Organometallic Chemistry 724 (2013) 225e234
Fig. 7. Absorption changes during the photodegradation studies of the compound 4 in toluene showing the disappearance of the Q-band at 10 min intervals. (Inset: Plot of
absorbance versus time).
values of the tetra-2-(4,6-diphenyl-1,3,5-triazine-2-yl)-5-(hex-
yloxy)phenoxy substituted Pc compounds (4e7) are lower than
unsubstituted zinc(II) Pc compound in toluene, being higher for the
oxotitanium (IV) phthalocyanine complex (6) than for the other
studied tetra substituted Pc compounds. On the contrary, the kF
value of the oxotitanium (IV) phthalocyanine complex (6) is lower
than the other studied tetra substituted Pc compounds and
unsubstituted zinc Pc as well. This could be the minimal aggrega-
tion behavior of this complex again.
generate highly singlet oxygen since the d10 configuration of the
central Zn2þ ion, which make them appropriate photosensitizers
for PDT applications. The metal-free phthalocyanine compound (4)
showed the lowest FD value among the studied tetra-substituted Pc
compounds (Table 2). It is suggest that the presence of metal ion in
the phthalocyanine cavity could be enhance intersystem crossing
between excites singlet and triplet states.
3.6. Photodegradation studies
Degradation of the compounds under light irradiation can be
used to study their stability and this is especially important for
those molecules intended for use in photocatalytic reactions. The
collapse of the absorption spectra without any distortion of the
shape confirms photodegradation not associated with photo-
transformation into different forms of MPc absorbing in the visible
region.
The spectral changes observed for all the tetra-2-(4,6-
diphenyl-1,3,5-triazine-2-yl)-5-(hexyloxy)phenoxy substituted Pc
compounds (4e7) during light irradiation are as shown in Fig. 7
(using the substituted metal-free phthalocyanine compound (4)
3.5. Singlet oxygen quantum yields
The quantity of the singlet oxygen quantum yield (FD) is a sign
of the capability of the compounds as photosensitizers in photo-
catalytic applications for instance PDT. In this study, the FD values
were determined in toluene using a chemical method and DPBF
used as a quencher. The disappearance of DPBF absorbance at
417 nm was monitored using UVevis spectrophotometer (Fig. 6 for
compound 5 as an example). There was no change in the Q band
intensity during the FD determinations, confirming that the studied
phthalocyanine compounds were not degraded during singlet
oxygen studies.
Many factors can be responsible for the magnitude of the singlet
oxygen generation such as triplet excited state energy, ability of
substituents and solvents to quench the singlet 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 photosensitizer
molecule is first excited to the singlet state and through inter-
1000
[BQ]=0
800
600
system crossing forms the triplet state, and then transfers the
P
[BQ]=saturated
energy to ground state oxygen, O2(3 g), generating excited singlet
state oxygen, O2(1Dg), the chief cytotoxic species, which subse-
quently oxidizes the substrate by Type II mechanism.
400
200
The FD values of the tetra-2-(4,6-diphenyl-1,3,5-triazine-2-yl)-
5-(hexyloxy)phenoxy substituted Pc compounds (4e7) are given in
Table 2. The studied tetra-substituted phthalocyanine compounds
showed lower FD values (0.20e0.40) than unsubstituted zinc (II) Pc
except for the FD value (0.60) of studied zinc(II) phthalocyanine
complex. The FD value of the complex 7 is higher than the other
studied phthalocyanine complexes in toluene. Generally, zinc
phthalocyanine compounds possess high triplet yields and they can
0
650
700
750
Wavelength (nm)
800
Fig. 8. Fluorescence emission spectral changes of the compound 4 (1.00 ꢀ 10ꢁ5 M) on
addition of different concentrations of BQ in toluene. [BQ] ¼ 0, 0.008, 0.016, 0.024,
0.032 and 0.040 M.

Ü. Demirbas¸ et al. / Journal of Organometallic Chemistry 724 (2013) 225e234
233
Fig. 9. SterneVolmer plots for BQ quenching of tetra-2-(4,6-diphenyl-1,3,5-triazine-2-yl)-5-(hexyloxy)phenoxy substituted Pcs (4e7) (C ¼ w1.00 ꢀ 10ꢁ5 M) in toluene. [BQ] ¼ 0,
0.008, 0.016, 0.024, 0.032 and 0.040 M.
as an example in toluene) and hence confirm photodegradation
occurred without phototransformation.
studied phthalocyanine compounds are also lower than unsub-
stituted ZnPc except for oxotitanium(IV) phthalocyanine complex
in toluene, thus generally substitution of phthalocyanine frame-
work with 2-(4,6-diphenyl-1,3,5-triazine-2-yl)-5-(hexyloxy)phe-
noxy groups seems to decrease the kq values of the compounds. The
highest kq value for complex 6 could be due to aggregation behavior
of this complex in toluene.
Table 2 shows that the Fd values of tetra-substituted Pc
compounds (4e7) are higher than unsubstituted zinc(II) Pc in
toluene. All the studied phthalocyanine compounds (4e7) less
stable to degradation under light irradiation compared to unsub-
stituted ZnPc in toluene due to electron-donating ability of the
substituted groups. The zinc(II) phthalocyanine complex (5) is the
most stable among the other studied compounds. Thus, the substi-
tution of phthalocyanine framework with 2-(4,6-diphenyl-1,3,5-
triazine-2-yl)-5-(hexyloxy)phenoxy groups seems to decrease the
stability of the compounds in toluene.
4. Conclusions
In conclusion, the 2-(4,6-diphenyl-1,3,5-triazine-2-yl)-5-(hex-
yloxy)phenoxy substituted phthalonitrile (3) and its metal-free (4),
zinc(II) (5), oxotitanium(IV) (6), lead(II) (7), nickel(II) (8), copper(II)
(9) and cobalt(II) (10) phthalocyanine derivatives have been
synthesized and characterized for the first time. The photophysical
and photochemical properties of metal-free (4), zinc(II) (5), oxoti-
tanium(IV) (6) and lead(II) (7) phthalocyanine compounds were
also described in toluene. The synthesized nickel(II) (8), copper(II)
(9) and cobalt(II) (10) phthalocyanines were not evaluated for this
purpose because of transition metal and paramagnetic behavior of
central metals in the cavity for these complexes. The substitution of
phthalocyanine framework with 2-(4,6-diphenyl-1,3,5-triazine-
2-yl)-5-(hexyloxy)phenoxy groups increased the wavelength of the
Q band. The Q bands of the lead phthalocyanine compound (7) are
red-shifted due to the non-planar effect of the bigger lead atom as
central atom. The photophysical and photochemical properties of
newly synthesized phthalocyanine complexes (5e7) were investi-
gated in toluene for comparison of the effect of metal atoms on the
Pc framework. The tetra-substituted metal-free (4), zinc(II) (5) and
oxotitanium(IV) (6) phthalocyanine compounds showed similar
and typical fluorescence behavior in toluene. But the shape of
excitation spectrum was different from the absorption spectrum for
studied lead(II) phthalocyanine compound (7) in toluene most
likely due to the larger lead metal being out of the plane of the
phthalocyanine ring. Only studied zinc(II) phthalocyanine complex
(5) showed higher singlet oxygen quantum yield than unsub-
stituted zinc Pc in toluene, but the singlet oxygen generation of
other studied compounds still enough for photocatalytic applica-
tions. The studied phthalocyanine compounds (5e7) were less
stable than unsubstituted zinc Pc since they showed higher pho-
todegradation quantum yield values than unsubstituted zinc Pc.
The substituted complexes showed lower KSV values when
3.7. Fluorescence quenching studies by 1,4-benzoquinone [BQ]
The fluorescence quenching of the tetra-2-(4,6-diphenyl-1,3,5-
triazine-2-yl)-5-(hexyloxy)phenoxy substituted phthalocyanine
compounds (4e7) by BQ in toluene was found to obey Sterne
Volmer kinetics, which is consistent with diffusion-controlled
bimolecular reactions. Fig. 8 shows the quenching of the metal-
free phthalocyanine compound (4) by BQ in toluene as an
example. The slope of the plots shown at Fig. 9 gave KSV values and
listed in Table 3. The KSV values of the studied tetra-substituted
phthalocyanine compounds (4e7) are lower than unsubstituted
zinc Pc in toluene. The substitution of 2-(4,6-diphenyl-1,3,5-
triazine-2-yl)-5-(hexyloxy)phenoxy groups on the phthalocyanine
framework seems to decrease the KSV values. The metal-free
phthalocyanine compound (4) compound showed the highest KSV
value; while the (7) compound showed the lowest KSV in toluene
could be related to the heavy atom effect of this compound in
toluene. The bimolecular quenching constant (kq) values of the
Table 3
Fluorescence quenching data for the unsubstituted and the tetra triazine substituted
phthalocyanine compounds in toluene.
Compound
KSV (Mꢁ1
)
kq/1010 (dm3 molꢁ1 sꢁ1
)
4
5
6
7
38.35
30.91
33.55
26.03
61.53a
2.11
2.08
3.35
1.05
2.19a
ZnPc
a
Ref. [37].

234
Ü. Demirbas¸ et al. / Journal of Organometallic Chemistry 724 (2013) 225e234
ꢀ
ꢀ
[19] P. S¸ en, F. Dumludag, B. Salih, A.R. Özkaya, Ö. Bekaroglu, Synthesis and elec-
trochemical, electrochromic and electrical properties of novel s-triazine
bridged trinuclear Zn(II), Cu(II) and Lu(III) and a tris double-decker Lu(III)
phthalocyanines, Synth. Met. 161 (2011) 1245e1254.
compared to the unsubstituted zinc(II) Pc in toluene. The substi-
tution of phthalocyanine framework with 2-(4,6-diphenyl-1,3,5-
triazine-2-yl)-5-(hexyloxy)phenoxy groups seems to decrease the
KSV and kq values of the compounds in toluene.
ꢀ
[20] M. Sülü, A. Altındal, Ö. Bekaroglu, Synthesis, characterization and electrical
and CO2 sensing properties of triazine containing three dendritic phthalocy-
anine, Synth. Met. 155 (2005) 211e221.
[21] D.D. Perrin, W.L.F. Armarego, Purification of Laboratory Chemicals, Pergamon,
Oxford, 1989.
Acknowledgment
[22] G.J. Young, W. Onyebuagu, Synthesis and characterization of di-disubstituted
phthalocyanines, J. Org. Chem. 55 (1990) 2155e2159.
[23] D. Maree, T. Nyokong, K. Suhling, D. Phillips, Effects of axial ligands on the
photophysical properties of silicon octaphenoxyphthalocyanine, J. Porphyr.
Phthalocya. 6 (2002) 373e376.
The authors thank to The Research Fund of Karadeniz Technical
University, Projects No: 2010.111.002.1. (Trabzon/Turkey).
References
[24] A. Ogunsipe, D. Maree, T. Nyokong, Solvent effects on the photochemical and
fluorescence properties of zinc phthalocyanine derivative, J. Mol. Struct. 650
(2003) 131e140.
[1] N.B. McKeown, Phthalocyanine Materials e Synthesis, Structure, and Function,
Cambridge University Press, Cambridge, 1998.
[25] H. .Du, R.A. Fuh, J. Li, A. Corkan, J.S. Lindsey, PhotochemCAD: a computer-aided
design and research tool in photochemistry, Photochem. Photobiol. 68 (1998)
141e142.
[26] I. Seotsanyana-Mokhosi, N. Kuznetsova, T. Nyokong, Photochemical studies
of tetra-2,3-pyridinoporphyrazines, J. Photochem. Photobiol. A 140 (2001)
215e222.
[27] A. Ogunsipe, T. Nyokong, Effects of substituents and solvents on the photo-
chemical properties of zinc phthalocyanine complexes and their protonated
derivatives, J. Mol. Struct. 689 (2004) 89e97.
[2] R. Bonnett, Chemical Aspects of Photodynamic Therapy, Gordon and Breach
Science, London, 2000.
[3] C.C. Leznoff, A.B.P. Lever, Phthalocyanines Properties and Applications, vol. 1,
VCH Publisher, New York, 1989.
[4] V. Parra, M. Bouvet, J. Brunet, M.L. Rodríguez-Méndez, J.A. Saja, On the effect of
ammonia and wet atmospheres on the conducting properties of different
lutetium bisphthalocyanine thin films, Thin Solid Films 516 (2008) 9012e9019.
[5] M. Bouvet, Phthalocyanine-based field-effect transistors as gas sensors, Anal.
Bioanal. Chem. 384 (2006) 366e373.
[28] J.H. Brannon, D. Magde, Picosecond laser photophysics e group-3a phthalo-
cyanines, J. Am. Chem. Soc. 102 (1980) 62e65.
[6] C.C. Leznoff, A.B.P. Lever, Phthalocyanines Properties and Applications, vol. 3,
VCH Publisher, New York, 1993.
[29] A. Ogunsipe, T. Nyokong, Photophysical and photochemical studies of sul-
phonated non-transition metal phthalocyanines in aqueous and non-aqueous
media, J. Photochem. Photobiol. A 173 (2005) 211e220.
[30] J. Rose, Advanced PhysicoeChemical Experiments, first ed., Sir Isaac Pitman &
Sons Ltd, London, 1964.
[7] G. de la Torre, P. Vazquez, F. Agullo-Lopez, T. Torres, Phthalocyanines and
related compounds: organic targets for nonlinear optical applications,
J. Mater. Chem. 8 (1998) 1671e1683.
[8] F. Yang, S.R. Forrest, Photocurrent generation in nano structured organic solar
cells, ACS Nano 2 (2008) 1022e1032.
[9] S.R. Forrest, Ultrathin organic films grown by organic molecular beam depo-
sition and related techniques, Chem. Rev. 97 (1997) 1793e1896.
[10] C.G. Classens, W.J. Blau, M. Cook, M. Hanack, R.J.M. Nolte, T. Torres, D. Wöhrle,
Phthalocyanines and phthalocyanine analogues: the quest for applicable
optical properties, Monatsh. Chem. 132 (2001) 3e11.
[11] J.A. Duro, G. de la Torre, J. Barber, J.L. Serrano, T. Torres, Synthesis and liquid-
crystal behavior of metal-free and metal-containing phthalocyanines
substituted with long-chain amide groups, Chem. Mater. 8 (1996) 1061e1064.
[12] M. Emmelius, G. Pawlowski, H.W. Vollmann, Materials for optical data storage,
Angew. Chem. Int. Ed. 28 (1989) 1445e1471.
_
ꢀ
ꢀ
[31] I. Degirmencioglu, R. Bayrak, M. Er, K. Serbest, The microwave-assisted
synthesis and structural characterization of novel, dithia-bridged polymeric
phthalocyanines containing a substituted thiophenylamine Schiff base, Dyes
Pigment. 83 (2009) 51e58.
_
ꢀ
ꢀ
[32] Y. Gök, H. Kantekin, I. Degirmencioglu, Synthesis and characterization of new
metal-free and metallophthalocyanines substituted with tetrathiadiazama-
crobicyclic moieties, Supramol. Chem. 15 (2003) 335e343.
_
ꢀ
ꢀ
[33] R. Bayrak, H.T. Akçay, M. Pis¸ kin, M. Durmu&scedil, I. Degirmencioglu, Azine-
bridged binuclear metallophthalocyanines functioning photophysical and
photochemical-responsive, Dyes Pigment. 95 (2012) 330e337.
[34] H. Engelkamp, R.J.M. Nolte, Molecular materials based an crown ether func-
tionalized phthalocyanines, J. Porphyr. Phthalocya. 4 (2000) 454e459.
[35] D.D. Dominguez, A.W. Snow, J.S. Shirk, R.S. Pong, Polyethyleneoxide-capped
phthalocyanines: limiting phthalocyanine aggregation to dimer formation,
J. Porphyr. Phthalocya. 5 (2001) 582e592.
[36] A. Ogunsipe, M. Durmus¸ , D. Atilla, A.G. Gürek, V. Ahsen, T. Nyokong, Synthesis,
photophysical and photochemical studies on long chain zinc phthalocyanine
derivatives, Synth. Met. 158 (2008) 839e847.
[13] C.C. Leznoff, A.B.P. Lever, Phthalocyanines Properties and Applications, vol. 4,
VCH Publisher, New York, 1996.
[14] F. Yılmaz, M. Özer, I. Kani, Ö. Bekaroglu, Catalytic activity of a thermo-
ꢀ
regulated, phase-separable Pd(II)-perfluoroalkylphthalocyanine complex in
an organic/fluorous biphasic system: hydrogenation of olefins, Catal. Lett. 130
(2009) 642e647.
[15] I. Rosenthal, Phthalocyanines as photodynamic sensitizers, Photochem. Pho-
tobiol. 53 (1991) 859e870.
[37] E.T. Saka, M. Durmus¸ , H. Kantekin, Solvent and central metal effects on
the photophysical and photochemical properties of 4-benzyloxybenzoxy
substituted phthalocyanines, Spectrochim. Acta 696 (2011) 913e924.
[38] M. Durmus¸ , T. Nyokong, Photophysicochemical and fluorescence quenching
studies of benzyloxyphenoxy-substituted zinc phthalocyanines, Spectrochim.
Acta A 69 (2008) 1170e1177.
[16] G. Jori, Photosensitised processes in vivo: proposed phototherapeutic appli-
cations, Photochem. Photobiol. 52 (1990) 439e443.
[17] T.J. Dougherty, A brief history of clinical photodynamic therapy development
at Roswell Park Cancer Institute, J. Clin. Laser Med. Surg. 14 (1996) 219e221.
[18] M.L. Yarmush, W.P. Thorpe, L. Strong, S.L. Rakestraw, M. Toner, R.G. Tompkins,
Antibody-targeted photolysis, Crit. Rev. Ther. Drug 10 (1993) 197e252.