Phthalocyanines prepared from 4-chloro-/4-hexylthio-5-(4-phenyloxyacetic acid)phthalonitriles and functionalization of the related phthalocyanines with hydroxymethylferrocene

Article abstract of DOI:10.1016/j.jorganchem.2009.09.025

The phthalonitrile derivative chosen for the synthesis of substituted phthalocyanines [M: 2H, Zn(II), Co(II)] with four chloro and four phenyloxyacetic acid substituents on the periphery is 4-chloro-5-(4-phenyloxyacetic acid)phthalonitrile. The sodium sal

Full text of DOI:10.1016/j.jorganchem.2009.09.025

Journal of Organometallic Chemistry 695 (2010) 45–52
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Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
Phthalocyanines prepared from 4-chloro-/4-hexylthio-5-(4-phenyloxyacetic
acid)phthalonitriles and functionalization of the related phthalocyanines
with hydroxymethylferrocene
*
Meryem Çamur, Mustafa Bulut
Marmara University, Department of Chemistry, 34722 Goztepe-Istanbul, Turkey
a r t i c l e i n f o
a b s t r a c t
Article history:
The phthalonitrile derivative chosen for the synthesis of substituted phthalocyanines [M: 2H, Zn(II),
Co(II)] with four chloro and four phenyloxyacetic acid substituents on the periphery is 4-chloro-5-(4-
phenyloxyacetic acid)phthalonitrile. The sodium salt of carboxyl substituted zinc phthalocyanine is good
soluble in water. Further reactions of zinc and cobalt phthalocyanines bearing phenyloxyacetic acid with
thionylchloride gave the corresponding acylchlorides. This functional group reacted with hydroxymeth-
ylferrocene in dry DMF to obtain ferrocenyl substituted phthalocyanines. Also chloro substituent in new
phthalonitrile was substituted with hexylsulfanyl substituent and its cyclotetramerization in the pres-
ence of Zn(AcO)2Á2H2O and 2-(dimethylamino)ethanol resulted with zinc phthalocyanine. The com-
pounds have been characterized by elemental analysis, MALDI-TOF mass, FT-IR, 1H NMR, UV–Vis and
fluorescence data. Aggregations properties of phthalocyanines were investigated at different concentra-
tions in tetrahydrofuran, dimethylformamide, dimethylsulfoxide, water, and water/ethanol mixture. Also
fluorescence spectral properties are reported.
Received 17 August 2009
Received in revised form 10 September
2009
Accepted 22 September 2009
Available online 29 September 2009
Keywords:
Water-soluble zinc phthalocyanine
Aggregation
Hydroxymethylferrocene
Fluorescence
Ó 2009 Elsevier B.V. All rights reserved.
1. Introduction
clude sulfonates [9–11], carboxylates [2,5,10,12], phosphonates
[13], and quaternarized amino groups [14–16].
Phthalocyanines (Pcs) have been under systematic study more
than 70 years; however, researchers are still interested in this class
of compounds [1]. Pc complexes are potential functional materials
for use as sensitizers, gas sensors, catalysis and electrocatalysis be-
cause of their high electron-transfer abilities [2]. Other technolog-
ical applications of these macrocycles have been intensively
investigated, such as electrophotography, photovoltaic and solar
cells, semiconductor devices, molecular electronics, Langmuir–
Blodgett films (LB), electrochromic display devices, low-dimen-
sional conductors and synthetic metals, liquid crystals, non-linear
optics, and optical disk [1,3]. Remarkable progress has been made
in recent years in the use of pc derivatives as sensitizers for photo-
dynamic therapy (PDT) of cancer [4,5]. A decisive disadvantage of
pcs is their low solubility in organic solvents or water. The solubil-
ity can be increased, however, by introducing bulky or long chain
groups, e.g. alkyl, alkoxy/alkylthio into the peripheral positions of
the pc framework [6–8]. For aqueous solutions it is necessary to
introduce hydrophilic chemical functional groups into benzene
rings of the basic pc skeleton [9]. The hydrophilic moieties which
have been incorporated on the peripheral positions of pc ring in-
Although the symmetrically octasubstituted (where all the
eight substituents are the same) and tetrasubstituted pcs have
been frequently encountered, octasubstituted pcs obtained from
disubstituted phthalonitrile derivatives with two different substit-
uents in the 4,5-positions are relatively less studied and only a few
well characterized species well known [17–19]. This new class of
substituted pcs usually exhibit high solubility [20]. In a sense,
these types of derivatives might be considered as alternatives to
asymmetrically substituted pcs which are getting more and more
important for their non-linear optical properties, Langmuir–Blodg-
ett film (LB) formation and mesogenic tendencies [21,22].
Phthalocyanine-based multicomponent systems have been ex-
plored, including porphyrins, ferrocenes, crown ethers, tetra-
thiafulvalenes, oligopridyl–metal complexes, dendrimers, and C60
[23]. Pcs have long been known to undergo electron-transfer reac-
tions, both to and from their excited states, and strong electron do-
nors such as ferrocene are able to quench the Pc fluorescence by
intermolecular electron-transfer [24,25]. The fascinating structural
properties of ferrocene and its derivatives have been the subject of
increasing interest in all fields of organometallic chemistry, since
the discovery of ferrocene in 1950 [26–28]. Therefore, synthesis
and investigation of novel phthalocyanine–ferrocene conjugates
are worthwhile.
* Corresponding author. Tel.: +90 216 3479641x1370; fax: +90 216 3478783.
E-mail address: mbulut@marmara.edu.tr (M. Bulut).
0022-328X/$ - see front matter Ó 2009 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2009.09.025

46
M. Çamur, M. Bulut / Journal of Organometallic Chemistry 695 (2010) 45–52
Recently, we have reported on the synthesis and characteriza-
(THF), methanol, dimethylformamide (DMF) and dimethyl sulfox-
tion of water-soluble symmetrical pcs bearing four 4-phenyloxy-
acetic acid functionalities [29]. We report here the synthesis of
two different singly substituted phthalonitriles with a phenyloxy-
acetic acid group. In these displacement reactions; one of two
chloro groups was replaced only. Metal-free and divalent metal
pcs [Zn(II) and Co(II)] with four peripheral chloro and four phenyl-
oxyacetic acid substituents have been synthesized from this pht-
halonitrile derivative. The phenyloxyacetic acid carries carboxyl
group that enables solubility in water (as a sodium salts) and, is
also suitable for a conjugation to the biomolecules. Zinc metallo
phthalocyanine’s sodium salt was prepared using sodium hydrox-
ide solution. Aggregation properties of this salt were investigated
in water and water/ethanol mixture. Pcs containing ferrocenylm-
ethyl 4-phenyloxyacetate moieties on the periphery have been
prepared with the reaction of hydroxymethylferrocene and octa-
substituted zinc and cobalt metallo pcs carrying four chloro and
phenyloxyacetic acid substituents. Also a new phthalonitrile with
a phenyloxyacetic acid and hexylsulfanyl substituents was synthe-
sized and the corresponding zinc metallo pc was prepared. The
bulky hexylsulfanyl substituent was chosen to prevent the aggre-
gation [5].
ide (DMSO). Yield: 1.31 g (83%). M.p. 202–205 °C. FT-IR (KBr),
m
2970–2916 (aliphatic CH), 2226 (C„N), 1709 (C@O), 1582–1481
(Ar C@C), 1281 (Ar–O–Ar). 1H NMR (d-DMSO 400 MHz): 12.40 (s,
1H, COOH), 8.57 (s, 1H, Ar–H), 7.65 (s, 1H, Ar–H), 7.38 (dd, 2H,
J = 8 Hz, Ar–H), 7.13 (dd, 2H, J = 8 Hz, Ar–H), 3.68 (s, 2H, CH2COOH).
max/(cmÀ1): 3449 (carboxylic acid OH), 3098–3028 (Ar–CH),
UV–Vis kmax (nm) (log e) in DMF: 281 (3.97).
2.2.2. 2,9,16,23-Tetra(chloro)-3,10,17,24-tetra(4-phenyloxyacetic
acid)-phthalocyanine (2)
A mixture of 1 (0.250 g, 0.80 mmol) and lithium metal (0.080 g,
11.43 mmol) was heated and stirred at 170 °C for 5 h under N2
atmosphere in the mixture of 1,2-dichlorobenzene (1.5 cm3) and
hexanole (1.5 cm3). After cooling to room temperature the green
mixture was treated with acetone to precipitate the product com-
pletely. The green precipitate was collected by centrifuging and
then washed with acetone. It was dissolved in a small amount of
methanol and precipitated by diluted HCl. In this mixture, the Li2pc
formed was converted into H2pc. The green precipitate was centri-
fuged and washed several times with water, hot ethanol, hot meth-
anol, ethyl acetate, acetone and diethyl ether, and dried in vacuo. It
is soluble in THF, DMF, DMSO, pyridine and water (at pH > 7).
Yield: 0.135 g (54%). M.p. >300 °C. FT-IR (KBr), m
max/(cmÀ1): 3425
(carboxylic acid OH), 3283 (NH), 3036 (Ar–CH), 2932–2843 (ali-
2. Experimental
phatic CH), 1732 (C@O), 1601–1435 (Ar C@C), 1250 (Ar–O–Ar).
UV–Vis kmax (nm) (log e) in THF: 286 (4.41), 339 (4.56), 604
2.1. Materials and equipment
(4.26), 631 (4.41), 663 (4.64), 697 (4.63). MS (MALDI-TOF, DHB
as matrix): m/z 1252.09 [M]+, 1253.08 [M+1]+, 1254.28 [M+2]+,
1324.05 [M+4H2O]+. Anal. Calc. for C64H38N8Cl4O12: C, 61.34; H,
3.04; N, 8.95. Found: C, 61.48; H, 3.01; N, 8.91%.
Infrared spectra (IR) were recorded on a Shimadzu FTIR-8300
Fourier Transform Infrared Spectrophotometer using KBr pellets,
electronic spectra on a Shimadzu UV-2450 UV–Vis Spectropho-
tometer. Elemental analyses were performed by the Instrumental
Analysis Laboratory of the TUBITAK Marmara Research Centre. 1H
NMR spectra were recorded on a Varian Mercury-VX 400 MHz
spectrometer using TMS as an internal standard. Mass spectra were
performed on a Bruker Autoflex III MALDI-TOF spectrometer. A 2,5-
dihydroxybenzoic acid (DHB, 20 mg/mL in THF) matrix was used.
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
2.2.3. 2,9,16,23-Tetra(chloro)-3,10,17,24-tetra(4-phenyloxyacetic
acid)-phthalocyaninatozinc(II) (3)
The compound 1 (0.100 g, 0.32 mmol) was dissolved in dry DMF
(1.5 cm3) and Zn(AcO)2Á2H2O (0.013 g, 0.06 mmol) was added and
the mixture was heated under stirring for 24 h at 160 °C under N2
atmosphere in a sealed glass tube. After cooling to room tempera-
ture, the reaction mixture was treated with diluted HCl to precip-
itate the product. The green solid was centrifuged and washed
several times successively with water, hot methanol, hot ethanol,
ethyl acetate, acetone and diethyl ether, and dried in vacuo. It is
soluble in DMF, DMSO, pyridine and water (at pH > 7). Yield:
micro tube. Finally, 1
ple plate, dried at room temperature and then analyzed. Fluores-
cence excitation and emission spectra were recorded on
lL of this mixture was deposited on the sam-
a
HITACHI F-7000 Fluorescence Spectrophotometer using 1 cm path
length cuvettes at room temperatures. 4,5-Dichlorophthalonitrile
was prepared according to the reported procedure [30] and 4-
hydroxyphenylacetic acid was purchased from Fluka Chemical
Company, and was used as purchased. All reagents and solvents
were of reagent-grade quality obtained from commercial suppliers.
All solvents were dried and purified. The solvents were stored over
molecular sieves (4 Å). The homogeneity of the products was
tested in each step using TLC (SiO2).
0.021 g (20%). M.p. >300 °C. FT-IR (KBr), m
max/(cmÀ1): 3379 (car-
boxylic acid OH), 3067–3036 (Ar–CH), 2947–2916 (aliphatic CH),
1728 (C@O), 1601–1458 (Ar C@C), 1242 (Ar–O–Ar). 1H NMR (d-
DMSO 400 MHz): 12.34 (br, s, 4H, COOH), 8.11–7.08 (br, 24H,
Ar–H), 3.70 (s, 8H, CH2COOH). UV–Vis kmax (nm) (log e) in DMF:
348 (4.33), 618 (4.03), 677 (4.54). MS (MALDI-TOF, DHB as matrix):
m/z 1315.21 [M]+, 1316.14 [M+1]+, 1317.31 [M+2]+, 1318.03
[M+3]+, 1319.35 [M+4]+, 1387.24 [M+4H2O]+, 1459.51 [M+8H2O]+.
Anal. Calc. for C64H36N8Cl4O12Zn: C, 58.40; H, 2.74; N, 8.52. Found:
C, 58.36; H, 2.71; N, 8.55%.
2.2. Synthesis
2.2.1. 4-Chloro-5-(4-phenyloxyacetic acid)phthalonitrile (1)
2.2.4. 2,9,16,23-Tetra(chloro)-3,10,17,24-tetra(4-phenyloxyacetic
acid)-phthalocyaninatocobalt(II) (4)
4,5-Dichlorophthalonitrile (1.00 g, 5.08 mmol) and 4-hydroxy-
phenylacetic acid (1.54 g, 10.16 mmol) were dissolved in anhy-
drous dimethylformamide (20 cm3) under N2 atmosphere. After
stirring for 10 min; finely ground anhydrous K2CO3 (2.80 g,
20.29 mmol) was added with stirring. The reaction mixture was
stirred at room temperature for 6 days under vacuum. Then the
mixture was treated with diluted HCl under ice cooling and the ob-
tained precipitate was filtered off, washed with water until the
washings were neutral. After drying in vacuo at 50 °C, the crude
product was purified by column chromatography with chloroform.
The compound is soluble in chloroform CHCl3, tetrahydrofuran
The compound 1 (0.100 g, 0.32 mmol) was dissolved in dry DMF
(1.5 cm3) and Co(AcO)2Á4H2O (0.015 g, 0.06 mmol) was added and
the mixture was heated under stirring for 24 h at 160 °C under N2
atmosphere in a sealed glass tube. After cooling to room tempera-
ture, the reaction mixture was treated with diluted HCl to precip-
itate the product. The green solid was centrifuged and washed
several times successively with water, hot methanol, hot ethanol,
ethyl acetate, acetone and diethyl ether, and dried in vacuo. It is
soluble in DMF, DMSO and pyridine. Yield: 0.051 g (48%). M.p.
>300 °C. FT-IR (KBr),
m
max/(cmÀ1): 3410 (carboxylic acid OH),

M. Çamur, M. Bulut / Journal of Organometallic Chemistry 695 (2010) 45–52
47
3065–3030 (Ar–CH), 2924–2876 (aliphatic CH), 1709 (C@O), 1605–
1439 (Ar C@C), 1250 (Ar–O–Ar). UV–Vis kmax (nm) (log ) in DMF:
2101.54 [M]+, 2102.23 [M+1]+. Anal. Calc. for C108H76N8Cl4O12-
CoFe4: C, 61.68; H, 3.62; N, 5.33. Found: C, 61.75; H, 3.68; N, 5.78%.
e
299 (5.01), 321 (5.01), 454 (4.29), 597 (4.58), 659 (4.87). MS (MAL-
DI-TOF, DHB as matrix): m/z 1309.15 [M]+, 1310.24 [M+1]+,
1311.36 [M+2]+, 1312.41 [M+3]+, 1381.04 [M+4H2O]+. Anal. Calc.
for C64H36N8Cl4O12Co: C, 58.67; H, 2.75; N, 8.56. Found: C, 58.93;
H, 2.68; N, 8.51%.
2.2.8. 4-Hexylthio-5-(4-phenyloxyacetic acid)phthalonitrile (8)
4-Chloro-5-(4-phenyloxyacetic acid)phthalonitrile (1) (1.00 g,
3.20 mmol) and n-hexanethiol (0.46 cm3, 3.20 mmol) were dis-
solved in dry DMF (20 cm3). After stirring for 10 min, anhydrous
K2CO3 (0.4416 g, 3.20 mmol) was added portion wise during
15 min with efficient stirring. The reaction mixture was stirred un-
der N2 atmosphere at room temperature for 7 days. Then the mix-
ture was poured into 100 cm3 ice–water. The resulting creamy
solid was collected by filtration and washed with water until the
washings were neutral. After drying in vacuo at 50 °C, the crude
product was purified by column chromatography with chloroform.
The compound is soluble in CHCl3, CH2Cl2, THF, methanol and ace-
2.2.5. Sodium salt of zinc metallo phthalocyanine (5)
Zinc metallo phthalocyanine (3) (0.02 g, 0.015 mmol) was dis-
solved in aqueous sodium hydroxide solution (5 cm3, 2 M), heated
until boiling, and cooled to the room temperature. Finally the solu-
tion was poured into ethanol to precipitate the product. The result-
ing mixture was centrifuged and the precipitate collected. After
washing with ethanol and acetone, the sodium salt of carboxylated
zinc metallo phthalocyanine was dried in vacuo. It is soluble in
tone. Yield: 0.160 g (12.7%). M.p. 106–108 °C. FT-IR (KBr), mmax
/
(cmÀ1): 3092–3038 (Ar–CH), 2965–2864 (aliphatic CH), 2237
(C„N), 1709 (C@O), 1578–1483 (Ar C@C), 1252 (Ar–O–Ar). 1H
NMR (d-DMSO 400 MHz): 12.28 (s, 1H, COOH), 8.04 (s, 1H, Ar–
H), 7.36 (s, 1H, Ar–H), 7.33 (dd, 2H, J = 8 Hz, Ar–H), 7.03 (dd, 2H,
J = 8 Hz, Ar–H), 3.58 (s, 2H, –CH2COOH), 3.11 (t, 2H, J = 6 Hz,
–SCH2R), 1.62 (m, 2H, –SCCH2R), 1.40 (m, 2H, –SCCCH2R), 1.25 (m,
4H, –SCCCCH2CH2CH3), 0.86 (t, 3H, J = 6 Hz, –SCCCCCCH3). UV–Vis
water. Yield: 0.017 g (80%). M.p. >300 °C. FT-IR (KBr), mmax
(cmÀ1): 3441, 3001, 1647, 1566, 1501, 1450, 1412, 1246, 1204.
UV–Vis kmax (nm) (log ) in water: 280 (4.62), 332 (4.62), 609
(4.45). UV–Vis kmax (nm) (log ) in water/EtOH (1/1): 280 (4.20),
/
e
e
341 (4.36), 628 (4.30), 658 (4.22).
2.2.6. 2,9,16,23-Tetra(chloro)-3,10,17,24-tetra(ferrocenylmethyl 4-
phenyloxyaceate)-phthalocyaninatozinc(II) (6)
kmax (nm) (log e) in DMF: 313 (4.19). MS (MALDI-TOF, DHB as ma-
trix): m/z 416.993 [M+Na]+, 432.968 [M+K]+, 466.108 [M+4H2O]+.
Zinc metallo phthalocyanine (3) (0.075 g, 0.057 mmol) was dis-
solved in thionylchloride (2 cm3) and refluxed for 4 h. At the end of
the reaction, thionylchloride was removed under reduced pressure.
The resulting solid was dissolved in 2 cm3 of freshly distilled DMF.
Hydroxymethylferrocene (0.062 g, 0.287 mmol) was dissolved in
dry DMF (1 cm3) and dropped into acid chloride at 0 °C. Triethyl-
amine (0.5 cm3) was added under continuous stirring and the mix-
ture was allowed to react for 24 h at room temperature. The
resulting solution was treated with methanol to precipitate the
product. The green solid was centrifuged and washed several times
successively with water, hot methanol, hot ethanol, ethyl acetate,
acetone and diethyl ether, and dried in vacuo. It is soluble in
DMF, DMSO and pyridine. Yield: 0.082 g (68%). M.p. >300 °C. FT-
2.2.9. 2,9,16,23-Tetra(hexylthio)-3,10,17,24-tetra(4-phenyloxyacetic
acid)-phthalocyaninatozinc (II) (9)
A
mixture of compound 8 (0.100 g, 0.253 mmol), Zn-
(AcO)2Á2H2O (0.0139 g, 0.063 mmol) and dry 2-(dimethylamino)eth-
anol (1.5 cm3) was heated and stirred at 160 °C in a sealed glass
tube for 24 h under N2 atmosphere. After cooling to room temper-
ature, diluted HCl was added in order to precipitate the product.
The green solid was centrifuged and washed with water until the
washings were neutral. It was dissolved in THF and precipitated
with chloroform. The product was washed several times with chlo-
roform. It is soluble in methanol, ethylacetate, THF, acetone, DMF
IR (KBr), m
max/(cmÀ1): 3064–3030 (Ar–CH), 2930–2910 (aliphatic
and DMSO. Yield: 0.026 g (27%). M.p. >300 °C. FT-IR (KBr), mmax
/
CH), 1723 (C@O), 1647–1431 (Ar C@C), 1243 (Ar–O–Ar). 1H NMR
(d-DMSO 400 MHz): 7.68–7.08 (br, 24H, Ar–H), 5.20 (s, 8H, ferro-
cene-CH2), 3.75 (s, 8H, CH2COOH), 4.31 (m, 16H, ferrocene), 4.14
(cmÀ1): 3404 (carboxylic acid OH), 3067–3028 (Ar–CH), 2924–
2857 (aliphatic CH), 1734 (C@O), 1599–1383 (Ar C@C), 1238 (Ar–
O–Ar). 1H NMR (d-DMSO 400 MHz): 12.03 (br, s, 4H, COOH),
8.20–7.03 (br, 24H, Ar–H), 3.61 (s, 8H, –CH2COOH), 2.94 (m, 8H,
–SCH2R), 1.60–1.19 (m, 32H, –SC(CH2)4CH3), 0.81 (m, 12H,
(m, 20H, ferrocene). UV–Vis kmax (nm) (log
609 (4.04), 681 (4.62). MS (MALDI-TOF, DHB as matrix): m/z
2107.06 2108.36 Anal. Calc. for
[M]+, [M+1]+.
e) in DMF: 317 (4.67),
–SCCCCCCH3).UV–Vis kmax (nm) (log e) in DMF: 356 (4.34), 616
C108H76N8Cl4O12ZnFe4: C, 61.51; H, 3.61; N, 5.32. Found: C, 61.64;
H, 3.18; N, 5.35%.
(3.92), 686 (4.61). MS (MALDI-TOF, DHB as matrix): m/z 1641.24
[M]+, 1642.35 [M+1]+, 1643.20 [M+2]+, 1666.26 [M+Na]+. Anal. Calc.
for C88H88N8O12S4Zn: C, 64.35; H, 5.36; N, 6.83. Found: C, 64.31; H,
5.41; N, 6.87%.
2.2.7. 2,9,16,23-Tetra(chloro)-3,10,17,24-tetra(ferrocenylmethyl 4-
phenyloxyaceate)-phthalocyaninatocobalt(II) (7)
Cobalt metallo phthalocyanine (4) (0.075 g, 0.057 mmol) was
dissolved in thionylchloride (2 cm3) and refluxed for 4 h. At the
end of the reaction, thionylchloride was removed under reduced
pressure. The resulting solid was dissolved in 2 cm3 of freshly dis-
tilled DMF. Hydroxymethylferrocene (0.062 g, 0.287 mmol) was
dissolved in dry DMF (1 cm3) and dropped into acid chloride at
0 °C. Triethylamine (0.5 cm3) was added under continuous stirring
and the mixture was allowed to react for 24 h at room tempera-
ture. The resulting solution was treated with methanol to precipi-
tate the product. The green solid was centrifuged and washed
several times successively with water, hot methanol, hot ethanol,
ethyl acetate, acetone and diethyl ether, and dried in vacuo. It is
soluble in DMF, DMSO and pyridine. Yield: 0.044 g (36.6%). M.p.
3. Results and discussion
The precursor material chosen for the synthesis of substituted
pcs with four chloro and four phenyloxyacetic acid substituents
on the periphery is 4-chloro-5-(4-phenyloxyacetic acid)phthalo-
nitrile (1). It was synthesized from 4,5-dichlorophthalonitrile by
displacement of the one chloro group by the phenolic -OH function
of the 4-hydroxyphenylacetic acid in DMF at room temperature. In
a study, when K2CO3 was used as a base, the chloro groups were
only partially substituted. However, in the case of Na2CO3, both
of the chloro groups were substituted [18,31]. In this study, accord-
ingly the corresponding compound was obtained when either of
these carbonates was used and the composition and structure of
the singly substituted phthalonitrile derivative is consistent with
all analytical results. The usual synthetic routes were applied to
obtain the metal-free pc (2) and the metallo pcs (3 and 4). Conver-
>300 °C. FT-IR (KBr),
2915 (aliphatic CH), 1719 (C@O), 1641–1435 (Ar C@C), 1249 (Ar–
O–Ar). UV–Vis kmax (nm) (log ) in DMF: 327 (5.11), 465 (4.47),
599 (4.33), 662 (4.78). MS (MALDI-TOF, DHB as matrix): m/z
m
max/(cmÀ1): 3070-3055 (Ar–CH), 2936–
e

48
M. Çamur, M. Bulut / Journal of Organometallic Chemistry 695 (2010) 45–52
sion of 1 into the metal-free pc 2 is accomplished in a mixture of 1,
2-dichlorobenzene and hexanole in the presence of lithium. Dilith-
ium pcs are labile towards water and acids, and can easily be con-
verted to the metal-free pc (2). The metallo pcs [M: Zn (3) and M:
Co (4)] were synthesized directly by cyclotetramerization of the
corresponding dicyano compound 1 in the presence of metal salts
[Zn(AcO)2Á2H2O and Co(AcO)2Á4H2O] in DMF. Sodium salt of zinc pc
(5) was obtained by heating 3 in diluted NaOH. Pcs (2–4) are solu-
ble in DMF, DMSO, pyridine and water (at pH>7). The series of
reactions are outlined in Scheme 1. Further reactions of 4-phenyl-
oxyacetic acid substituted phthalocyanines (3 and 4) first with
thionylchloride and then hydroxymethylferrocene in DMF gave
ferrocenyl substituted phthalocyanines (6 and 7) (Scheme 2). Ferr-
ocenyl substituted pcs (6 and 7) are slightly soluble in DMF and
DMSO.
dinitrile derivative (1) into pcs (2–4), the sharp peak for the
C„N vibrations disappeared. The NH group of the metal-free pc
(2) in the inner core gave a weak absorption peak at 3283 cmÀ1
.
In the IR spectra, C–H stretching vibrations of aliphatic and ferro-
cene methylene groups and C@O vibration of ester appear at ca.
2930–2910, 1723 cmÀ1 for 6 and 2936–2915, 1719 cmÀ1 for 7,
respectively. In the 1H NMR analysis of 1 in d-DMSO, the carboxylic
acid proton appear as a singlet at d 12.40 ppm, the aromatic pro-
tons of phenyloxy group as doublet of doublet at d 7.38 and
7.13 ppm. The aromatic proton ortho to chloro group appears as
a singlet at d 7.65 ppm and the other aromatic proton ortho to phe-
nyloxy group as a singlet at d 8.57 ppm. The 1H NMR spectra of the
pcs are rather broad, owing probably to the aggregation of the pcs
which is frequently encountered at the concentrations used for
NMR spectroscopy. The 1H NMR spectrum of 3 indicates carboxylic
acid protons at d 12.34 ppm as a broad singlet, aromatic protons at
d 8.11–7.08 ppm as broad and aliphatic protons (CH2) d 3.70 ppm
as a singlet. When going from 3 to 6, chemical shifts for the ferro-
cene groups emerge at d 4.31 and 4.14 ppm as multiplets.
The MALDI-TOF mass spectra of 2, 3, 4, 6 and 7 confirmed the
proposed structures; molecular ions were easily indentified at m/
z: 1252 [M]+ for 2, at m/z: 1315 [M]+ for 3 (Fig. 1), at m/z: 1309
[M]+ for 4, at m/z: 2107 [M]+ for 6 and at m/z: 2101 [M]+ for 7.
Comparison of the IR spectra of 1 and 8 gave some hints the nat-
ure of the products. The IR spectrum of 8 clearly indicates the pres-
ence of the alkylsulfanyl substituent by the intense stretching
bands at 2965–2864 cmÀ1 (aliphatic C–H). In addition, the charac-
teristic vibrations of the C„N appear at 2237 cmÀ1. In the 1H NMR
analysis of 8 in d-DMSO, the carboxylic acid proton appear as a sin-
glet at d 12.28 ppm, the aromatic protons of phenyloxy group as a
doublet of doublet at d 7.33 and 7.03 ppm. The aromatic protons
ortho to the cyano group appear as two singlets at d 8.04 and
Compound 1 was reacted with n-hexanethiol in presence of a
base (K2CO3) in anhydrous DMF at room temperature for seven
days to give 4-hexylthio-5-(4-phenyloxyacetic acid)phthalonitrile
(8). In this reaction, the long reaction times were necessary for
good yield. Cyclotetramerization of this new asymmetrically
disubstituted phthalonitrile derivative 8 into zinc metallo pc (9)
was accomplished by reaction with Zn(AcO)2Á2H2O in anhydrous
2-(dimethylamino)ethanol (Scheme 3). The most obvious feature
of the zinc metallo pc (9), when compared with that of the 1-
chloro-3,4-dicyano-6-(4-phenyloxyacetic acid)benzene substi-
tuted analog (2–4) is its extensive solubility in common organic
solvents (e.g. methanol, ethylacetate, acetone, THF, DMF, DMSO).
The structure of each compound was elucidated using elemental
analysis, FT-IR, 1H NMR, UV–Vis and MALDI-TOF methods. All the
analytical and spectral data were consistent with predicted
structures.
The IR spectrum of 1, peaks around 1709 cmÀ1 indicate the
presence of C@O group and the band at 3449 cmÀ1 corresponds
to –OH of the COOH group. In addition, the characteristic vibra-
tions of the C„N appear at 2226 cmÀ1. After conversion of the
7.36 ppm. The aliphatic CH3 protons appear as triplet at
d
0.86 ppm, the –SCH2 protons as triplet at d 3.11 ppm, and the
–CCH2C– in the long chain as multiplets at the range of d 1.25–
Scheme 1. Synthetic pathway of 4-chloro-5-(4-phenyloxyacetic acid)phthalonitrile (1) and phthalocyanines (2-5).

M. Çamur, M. Bulut / Journal of Organometallic Chemistry 695 (2010) 45–52
49
Scheme 2. Synthesis of ferrocenyl substituted phthalocyanines (6 and 7).
Scheme 3. Chemical structure and synthesis of 4-hexylthio-5-(4-phenyloxyacetic acid)phthalonitrile (8), zinc metallo phthalocyanine (9).
1.62 ppm. The 1H NMR spectrum of 9 indicates the carboxylic acid
protons at d 12.03 ppm as a broad singlet, the aromatic protons at d
8.20–7.03 ppm as broad, the –SCH2 protons at d 2.94 ppm as mul-
tiplet, the –SC(CH2)4C– protons in the long chain at d 1.60–
1.19 ppm as multiplet and the –CH3 protons at the end of the chain
at d 0.85 ppm as multiplet. The MALDI-TOF mass spectra of zinc pc
(9) confirmed the proposed structure; molecular ion was easily
identified at m/z: 1641 [M]+.
The ground state electronic spectra of the complexes showed
characteristic absorption in the Q band region at 697 and 663 nm

50
M. Çamur, M. Bulut / Journal of Organometallic Chemistry 695 (2010) 45–52
Fig. 1. Mass spectrum of 3.
for 2, 677 nm for 3, 659 nm for 4, 681 nm for 6, 662 nm for 7 and
686 nm for 9. The B band region was observed around 320–
356 nm (Fig. 2). The spectra showed monomeric behavior evi-
denced by a single Q band, typical of metalled pc complexes for
3, 4, 6, 7 and 9 in DMF which depict the monomeric nature of these
complexes. The metal-free pc 2 gave doublet Q band as a result of
the D2h symmetry. It was found that the Q band of zinc metallo pc
3 is red shifted (18 nm) as compared with that of cobalt metallo pc
4 in DMF. Compared with the corresponding phthalocyanines 3, 4,
the absorption maxima of 6, 7 are bathochromically shifted by
about 3 nm (Fig. 3). It is possible to suggest that the ferrocenyl
group is electronically independent in compound 3 and 4. When
compared with phenyloxyacetic acid and chloro substituted zinc
metallo pc (3), substitution of chloro group with alkylsulfanyl moi-
ety leads to a shift of 9 nm to longer wavelength (Fig. 3). In this
study, the aggregation behavior of the metal-free pc 2 is investi-
gated in THF, DMF and DMSO. While compound 2 did not showed
an aggregation in THF, it showed aggregation in DMF and DMSO as
judged by a blue shift of the Q band [32] (Fig. 4). In general, DMSO
and DMF are strong coordinating solvents since they are known as
the aggregation preventing solvents. However, compound
2
showed aggregation in these solvents and the same effect has been
observed in the literature [33]. The aggregation behavior of the pc
2 was also investigated at different concentrations in THF. In THF,
as the concentration was increased, the intensity of absorption of
the Q band also increased and there were no new bands due to
the aggregated species.
In order to improve the solubility of pcs in water, four hydro-
philic carboxylic acid groups at the periphery of the ring structure
was introduced. The sodium salt of carboxyl substituted pc (5) is
Fig. 2. Absorption spectra of the compounds 2 (in THF), 3 (in DMF) and 4 (in DMF).
Fig. 3. Absorption spectra of the compounds 3, 6 and 9 in DMF.

M. Çamur, M. Bulut / Journal of Organometallic Chemistry 695 (2010) 45–52
51
Table 1
Absorption, excitation and emission spectral data for phthalocyanines 2, 3, 4 and 9.
Compound Q band
kmax (nm)
Log
e
Excitation Emission Stokes shift
kEx (nm) kEm (nm) Dstokes (nm)
2
3
4
9
697, 663
4.63, 4.64 703, 670
709
690
–
12
13
–
677
659
686
4.54
4.87
4.61
684
–
694
701
15
Fig. 4. Absorption spectra of the compound 2 in different solvents.
Fig. 5. Absorption spectra of 5. Thick line: in water; thin line: in aqueous ethanol
solution (v/v = 1/1).
Fig. 7. Fluorescence emission and excitation spectra of
2
in THF. Excitation
wavelength = 630 nm (A); fluorescence emission and excitation spectra of 3 in
DMF. Excitation wavelength = 615 nm (B); fluorescence emission and excitation
spectra of 9 in DMF. Excitation wavelength = 616 nm (C).
soluble in water. However, the absorption band in water and that
in aqueous ethanol solution differs because aggregation takes place
in water [11,34], which makes the Q band blue shifted due to the
exciton coupling effectively raising the energy level of the excited
state [3]. With addition of ethanol to the aqueous solution, disag-
gregation takes place as shown in Fig. 5.
Fig. 6. Emission spectra of 2, 3, 4, 6,
length = 630 nm for 2; 615 nm for 3, 602 nm for 4, 609 nm for 6, 599 nm for 7
and 616 nm for 9.
7 and 9 in DMF. Excitation wave-

52
M. Çamur, M. Bulut / Journal of Organometallic Chemistry 695 (2010) 45–52
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3, 4, 6, 7 and 9. While the pcs 2, 3, 6 and 9 are fluorescent, the pcs 4
and 7 do not show fluorescence at excitation wavelength. The pcs 2,
3 and 9 showed similar fluorescence behavior in DMF. In DMF,
emission peaks were observed at 709 nm (2), 690 nm (3) and
701 nm (9) (Table 1). The excitation spectra were similar to absorp-
tion spectra and both were mirror images of the fluorescence spec-
tra [35] (Fig. 7). In contrast to absorption properties, fluorescence
properties of the phenyloxyacetic acid substituted pc (3) is strongly
affected by the presence of ferrocenyl substituents. Pc 3 possesses
high fluorescence intensity, while the ferrocene-substituted pc 6
is poor fluorescent intensity. In fact, it has been reported that cova-
lently linked ferrocenes substantially quenched the fluorescence
emission of other chromophores, for example; porphyrins, through
an intramolecular electron-transfer process [36,37]. The proximity
of wavelength of each component of the Q band absorption to the Q
band maxima of the excitation spectra for pcs 2, 3 and 9 suggests
that the nuclear configurations of the ground and excited states
are similar and not affected by excitation in DMF. The observed
Stokes shifts (Table 1) were typical of pc complexes in DMF.
Acknowledgement
We are thankful to the Scientific and Research Council of Turkey
(TÜBITAK) (107T347 and 108T623).
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