Design, syntheses, spectroscopic, aggregation properties of novel peripheral octa-substituted zinc(II), magnesium(II) and lead(II) phthalocyanines and investigation of their photocatalytic properties on the photooxidation of 4-nitrophenol

Article abstract of DOI:10.1016/j.inoche.2020.107998

In the present paper, the syntheses, spectroscopic characterization, aggregation behaviours and photocatalytic properties of phthalocyanine compounds were searched. Octa-substituted phthalocyanines (Zn^II (Pc-Zn), Mg^II (Pc-Mg) and Pb^II (Pc-Pb)) with eight peripheral (E)-3-(3-hydroxyphenyl)-1-(2,4,5-trimethoxyphenyl)prop-2-en-1-one groups were synthesized by cyclotetramerization. The spectral properties of these compounds were carried out that used widespread spectroscopic techniques. Later on, aggregation properties of synthesized phthalocyanines were examined in polar and apolar solvents. In addition to this, the photocatalytic activities of new synthesized metallophthalocyanines containing various central metal ions (zinc (II), magnesium (II) and lead (II)) were investigated. Three different metal centered phthalocyanines have been prepared for the photodegradation of 4-nitrophenol. In the photodegradation reactions that carried out in the photoreactor for 1 h without using any oxidant, 4-nitrophenol compound was completed with 90% (for Pb^II (Pc-Pb)), 56% (for Zn^II (Pc-Zn)) and 12% (for Mg^II (Pc-Mg)) conversion from toxic species to non-harmful species and unknown intermediates. The turnover numbers were determined as 1500 for Pb^II (Pc-Pb), 933 for Zn^II (Pc-Zn).

Full text of DOI:10.1016/j.inoche.2020.107998

Inorganic Chemistry Communications 118 (2020) 107998
Contents lists available at ScienceDirect
Inorganic Chemistry Communications
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Short communication
Design, syntheses, spectroscopic, aggregation properties of novel peripheral
octa-substituted zinc(II), magnesium(II) and lead(II) phthalocyanines and
investigation of their photocatalytic properties on the photooxidation of 4-
nitrophenol
Halise Yalazan, Kader Tekintas, Vildan Serdaroğlu, Ece Tugba Saka, Nuran Kahriman,
⁎
Halit Kantekin
Department of Chemistry, Faculty of Sciences, Karadeniz Technical University, Trabzon, Turkey
G R A P H I C A L A B S T R A C T
A R T I C L E I N F O
A B S T R A C T
Keywords:
Syntheses
Chalcone
In the present paper, the syntheses, spectroscopic characterization, aggregation behaviours and photocatalytic
II
II
properties of phthalocyanine compounds were searched. Octa-substituted phthalocyanines (Zn (Pc-Zn), Mg
II
(
Pc-Mg) and Pb (Pc-Pb)) with eight peripheral (E)-3-(3-hydroxyphenyl)-1-(2,4,5-trimethoxyphenyl)prop-2-en-
4
-nitrophenol
1
-one groups were synthesized by cyclotetramerization. The spectral properties of these compounds were carried
Phthalocyanines
Photodegradation
out that used widespread spectroscopic techniques. Later on, aggregation properties of synthesized phthalo-
cyanines were examined in polar and apolar solvents. In addition to this, the photocatalytic activities of new
synthesized metallophthalocyanines containing various central metal ions (zinc (II), magnesium (II) and lead
(
II)) were investigated. Three different metal centered phthalocyanines have been prepared for the photo-
degradation of 4-nitrophenol. In the photodegradation reactions that carried out in the photoreactor for 1 h
II
II
without using any oxidant, 4-nitrophenol compound was completed with 90% (for Pb (Pc-Pb)), 56% (for Zn
II
(
Pc-Zn)) and 12% (for Mg (Pc-Mg)) conversion from toxic species to non-harmful species and unknown in-
II
II
termediates. The turnover numbers were determined as 1500 for Pb (Pc-Pb), 933 for Zn (Pc-Zn).
⁎
Corresponding author at: Department of Chemistry, Karadeniz Technical University, 61080 Trabzon, Turkey.
E-mail address: halit@ktu.edu.tr (H. Kantekin).
https://doi.org/10.1016/j.inoche.2020.107998
Received 4 April 2020; Received in revised form 21 May 2020; Accepted 2 June 2020
Available online 04 June 2020
1387-7003/ © 2020 Elsevier B.V. All rights reserved.

H. Yalazan, et al.
Inorganic Chemistry Communications 118 (2020) 107998
1
. Introduction
portion-wise over a period of 30 min to the mixture. The obtained
mixture was heated to 55 °C and left to stir for 5 days under the ni-
trogen stream in a Schlenk system. During the entire reaction, mixture
was controlled with TLC used chloroform/ethanol (10:1) solvent system
and accordingly, the progress of the reaction was terminated. The
mixture was poured into crushed ice and mixed under room conditions
for about 1 h. Immediately after, the formed solid precipitates were
filtered and dried in vacuo. Purification of the formed solid phthalo-
nitrile was carried out by column chromatography method. In conclu-
sion, title product (3) was obtained as yellow solid.
Phthalocyanines (Pcs) containing four isoiminoindole units are
planar aromatic macrocyclic compounds having 18-π electron system
[
1]. Because of their unique optical, electronic, structural and catalytic
properties, Pcs have been examined comprehensively in recent years
[
2]. In addition, phthalocyanines have many technological application
areas such as photodynamic therapy, catalyst and photocatalytic, liquid
crystals, antimicrobial properties, DNA photocleavage and anti-cancer
activity [3–9].
Aggregation is an important factor for phthalocyanine compounds,
because it prevents the usage of phthalocyanine in many application
areas. Two types aggregation is observed in the substituted phthalo-
cyanines. These are called H-aggregation (face-to-face) and J-aggrega-
tion (side-to-side) [1,10]. In general, while aggregation ensues in a
decrease in intensity of the Q band a new, broader and blue-shifted or
red-shifted band is seen to increase in intensity. The H-aggregation is
seen a lower wavelength shift in Pcs. On the contrary, the J-aggregation
corresponding to red-shifted is observed a higher wavelength shift and
is rarely seen in phthalocyanines [11–15]. The insolubility of phthalo-
cyanines in common organic solvents is another important factor. The
solubility of phthalocyanines can be enhanced by binding bulky sub-
stituents such as crown ether, long chain groups, phenoxy, alkylthio,
alkoxy, and alkyl groups on the non-peripheral and peripheral positions
to phthalocyanine ring [16–18]. Therefore, methoxylated chalcone
group was chosen to hinder the aggregation behavior and to enhance
solubility of the Pcs compounds in this work [19].
Yield: 74% (1.32 g), solvent of column chromatography: chloro-
−1
form, m.p: 123–125 °C. FT–IR (ATR), υmax (cm ): 3075(AreH),
2934–2835 (Aliph. CeH), 2228 (C^N), 1650, 1573, 1501, 1464, 1437,
1
1353, 1267, 1207–1142 (AreOeAr), 1075, 972, 858, 787, 753.
H
NMR (400 MHz, DMSO‑d ), (δ:ppm): 7.88–7.83 (d, 2H, ]CHe), 7.63
6
(d, 2H, eCH]), 7.59 (s, 1H, AreH), 7.56 (s, 1H, AreH), 7.54 (s, 1H,
AreH), 7.50 (s, 1H, AreH), 7.49–7.45 (m, 2H, AreH), 7.18–7.15 (m,
2H, AreH), 6.79 (s, 2H, AreH), 6.77–6.76 (d, 2H, AreH), 6.73 (s, 2H,
AreH), 3.88 (s, 12H, eOeCH
3
), 3.74 (s, 6H, eOeCH
3
).
+
MALDI–TOF–MS m/z: Calculated: 752.76; Found: 752.725 [M]
.
2.1.2. Synthesis method of metallophthalocyanine compounds (Pc-Zn,Pc-
Mg and Pc-Pb)
Anhydrous metal salt Zn(OAc) (12 mg, 0.066 mmol for Pc-Zn) or
2
MgCl
2
(6.32 mg, 0.066 mmol for Pc-Mg) or Pb(OAc)
2
(21 mg,
0.066 mmol for Pc-Pb) and the phthalonitrile (3) (0.1 g, 0.133 mmol)
were solved in 3 mL n-amyl alcohol and immediately after, 5 drops DBU
for each was attached in mixture. This mixture was heated to boiling
Chalcones area medically privileged compounds [20]. They are used
in many modern applications such as photodynamic therapy, nonlinear
optical devices, electrochemistry, biomedical, catalytic and applica-
tions. [21–25].
point of the solvent in a prevalent Schlenk tube for 22 h under N at-
2
mosphere. At the end of this period, the mixture was cooled to room
conditions and precipitated by the addition of ethyl alcohol. The pre-
cipitated crude product was filtered and purification of the formed solid
Photocatalysis has been acknowledged as hopeful method for water
and air purification and since then, it has been examined comprehen-
sively as an alternative to presently used technologies [26,27]. 4-Ni-
trophenol (4-NP) is a precedence pollutant listed by the USEPA on ac-
count of its great toxicity to the global environment and human health,
even at low concentrations [28,29]. Of date, diverse techniques for the
degradation of 4-NP from wastewater have been notified such as wet air
oxidation degradation, biodegradation and photocatalytic degradation
II
II
products (Zn (Pc-Zn) and Mg (Pc-Mg)) were carried out by column
II
chromatography method, but Pb (Pc-Pb) phthalocyanine, till the fil-
trate was colorless, it was washed with ethyl alcohol and diethyl ether.
II
II
Finally, Zn (Pc-Zn) and Mg (Pc-Mg) metallophthalocyanines were
II
obtained as turquoise blue solids, but Pb (Pc-Pb) was obtained as
grass-green solid.
[
30,31]. Phthalocyanine compounds become promising candidate as
2.1.2.1. Zinc(II) phthalocyanine (Pc-Zn). Yield: 80% (41 mg), solvent
the metal centers as well as nitrogen active sites are responsible for
redox reactions that give rise to the pseudo capacitive behavior
system of column chromatography: chloroform/ethyl alcohol (50:1),
−1
m.p. > 300 °C. FT–IR (ATR), υmax (cm ): 3066 (AreH), 2930–2850
[
32–38].
(Aliph. CeH), 1723, 1644, 1578, 1509, 1438, 1267–1207–1176
1
In our previous studies, we synthesized phthalocyanine compounds
(AreOeAr), 1085, 974, 875, 787, 746. H NMR (400 MHz, DMSO‑d
6
),
peripheral and non-peripheral tetra substituted with methoxylated
chalcone group [39,40]. We wondered how substitution different po-
sitions of methoxy group on the chalcone skeleton impress photo-
catalytic properties of phthalocyanine compounds. Hence, in present
study, we synthesized nonaggregated, organo-soluble, octa-substituted
(δ:ppm): 7.65–7.54 (m, 44H, AreH and ]CHe), 7.53–7.33 (m, 14H,
AreH and eCH]), 7.25–7.19 (m, 8H, AreH), 6.78–6.58 (m, 6H,
AreH), 3.66 (s, 18H, eOeCH
3
), 3.37 (s, 54H, eOeCH ). UV–vis
3
(DMF),
λ
max
, nm (logε): 680 (4.96), 614 (4.30), 354 (4.88).
MALDI–TOF–MS m/z: Calculated for (Pc-Zn):3076.45; Found:3304.42
II
II
II
[M+DIT+2H]+
metallophthalocyanines (Zn (Pc-Zn), Mg (Pc-Mg) and Pb (Pc-Pb))
.
(
see Scheme 1). We have also researched the photocatalytic activities of
these new metallophthalocyanines.
2.1.2.2. Magnesium(II) phthalocyanine (Pc-Mg). Yield: 66% (33 mg),
solvent system of column chromatography: chloroform/ethyl alcohol
−1
2
. Experimental
(50:2), m.p. > 300 °C. FT–IR (ATR), υmax (cm ): 3066 (AreH),
2
930–2851 (Aliph. CeH), 1721, 1604, 1578, 1508, 1438,
1
The photodegradation procedure, equipment, the remaining figures
1268–1203–1176 (AreOeAr), 1080, 975, 870, 785, 752. H NMR
and materials were given as Supplementary Information.
(400 MHz, DMSO‑d
.54–7.33 (m, 16H, AreH and eCH]), 7.28–7.02 (m, 8H, AreH),
6.64–6.53 (m, 6H, AreH), 3.69 (s, 18H, eOeCH ), 3.37 (s, 54H,
eOeCH ). UV–vis (DMF), λmax, nm (logε): 680 (4.79), 613 (4.16), 346
6
), (δ:ppm): 7.94–7.62 (m, 42H, AreH and ]CHe),
7
2.1. Syntheses
3
3
2
.1.1. 4,5-bis(3-((E)-3-oxo-3-(2,4,5-trimethoxyphenyl)prop-1-enyl)
(4.85). MALDI–TOF–MS m/z: Calculated for (Pc-Mg): 3035.37;
phenoxy)phthalonitrile (3)
Found:3260.28 [M+DIT–H]+
.
(
E)-3-(3-hydroxyphenyl)-1-(2,4,5-trimethoxyphenyl)prop-2-en-1-
one (1) (1.50 g, 4.77 mmol) and 4,5-dichlorophthalonitrile (2) (0.47 g,
.39 mmol) were dissolved in 10 mL dry dimethylformamide. Then by,
finely ground anhydrous K CO (1.97 g, 14.30 mmol) was added
2.1.2.3. Lead(II) phthalocyanine (Pc-Pb). Yield: 87% (46 mg),
−1
2
m.p. > 300 °C. FT–IR (ATR), υmax (cm ): 3061 (AreH), 2931–2842
(Aliph. CeH), 1721, 1647, 1575, 1508, 1437, 1265–1206–1176
2
3
2

H. Yalazan, et al.
Inorganic Chemistry Communications 118 (2020) 107998
II
Scheme 1. Syntheses of (E)-3-(3-hydroxyphenyl)-1-(2,4,5-trimethoxyphenyl)prop-2-en-1-onesubstituted phthalonitrile (3) and metallophthalocyanines (Zn (Pc-Zn),
II
II
Mg (Pc-Mg) and Pb (Pc-Pb)). Reagents and conditions (i) N
2
, K
2
CO
3
, DMF, 55 °C (ii) N
2
, n-amyl alcohol, DBU, Zn(OAc)
2
, MgCl
2
, Pb(OAc) , reflux temperature.
2
Fig. 1. FT-IR spectrums of phthalonitrile and metallophthalocyanines (ZnII (Pc-Zn), MgII (Pc-Mg) and PbII (Pc-Pb)).
1
(
AreOeAr), 1078, 974, 856, 786, 744. H NMR (400 MHz, DMSO‑d
6
),
3. Results and discussion
(
δ:ppm): 7.61–7.55 (m, 46H, AreH and ]CHe), 7.51–7.30 (m, 12H,
AreH and eCH]), 7.26–7.09 (m, 8H, Ar–H), 6.71–6.61 (m, 6H,
3.1. Syntheses and characterization
AreH), 3.73 (s, 9H, eOeCH
3
), 3.67 (s, 9H, eOeCH
3
), 3.37 (s, 54H,
eOeCH
3
). UV–vis (DMF), λmax, nm (logε): 711 (4.57), 642 (3.99), 344
Common synthesis route of the obtained phthalonitrile (3) and
II II II
(
4.90). MALDI–TOF–MS m/z: Calculated for (Pc-Pb): 3218.27; Found:
peripheral octa-substituted Zn (Pc-Zn), Mg (Pc-Mg) and Pb (Pc-Pb)
phthalocyanines are exhibited in Scheme 1.The phthalonitrile (3) was
attained by the aromatic nucleophilic substitution reaction of 4,5-di-
chlorophthalonitrile (2) with (E)-3-(3-hydroxyphenyl)-1-(2,4,5-
+
3
412.12 [M+DIT–OCH –H] .
3
3

H. Yalazan, et al.
Inorganic Chemistry Communications 118 (2020) 107998
trimethoxyphenyl)prop-2-en-1-one (1) using
K
2
CO
3
in dry di-
spectra of MPcs were measured by the MALDI–TOF spectral data, the
+
methylformamide at 55 °C under N
2
atmosphere for 5 days. Me-
molecular ion peaks were observed at m/z: 3304.42 [M+DIT+2H] for
II
+
tallophthalocyanines representing the result compounds (Zn (Pc-Zn),
(Pc-Zn), 3260.28 [M+DIT–H] for (Pc-Mg) and 3412.12 [M+DI-
II
II
+
Mg (Pc-Mg) and Pb (Pc-Pb)) were accomplished by the cyclote-
tramerization of phthalonitrile (3), in the presence of anhydrous metal
TeOCH
3
eH] for (Pc-Pb) (see Figs. S2–S4).
The UV–vis spectra of the novel peripheral octa-substituted me-
salts (Zn(OAc)
2
, MgCl
2
, Pb(OAc)
2
) and DBU in n-amyl alcohol for 22 h.
tallophthalocyanines (Pc-Zn, Pc-Mg and Pc-Pb) were recorded at a
−5
Purification of the obtained metallophthalocyanines was carried out by
concentration of 1.0 × 10
M in DMF. The Q band absorptions of
column chromatography method. These novel MPcs (Pc-Zn, Pc-Mg and
these compounds were observed at 680 nm (logε = 4.96) for Pc-Zn,
680 nm (logε = 4.79) for Pc-Mg and 711 nm (logε = 4.57) for Pc-Pb
and lower wavelength vibronic band at 614 nm (logε = 4.30) for Pc-
Zn, 613 nm (logε = 4.16) for Pc-Mg and 642 nm (logε = 3.39) for Pc-
Pb, respectively. Also, the B–band absorptions were exhibited at
354 nm (logε = 4.88) for Pc-Zn, 346 nm (logε = 4.85) for Pc-Mg and
344 nm (logε = 4.90) for Pc-Pb, respectively in the UV region.
Pc-Pb) demonstrated good solubility in chloroform (CHCl ), di-
3
chloromethane (CH
2
2
Cl ), dimethylformamide (DMF), dimethylsulph-
oxide (DMSO) and tetrahydrofurane (THF). The structures of phthalo-
nitrile and metallophthalocyanines were proved using spectroscopic
techniques such as FT–IR, MALDI–TOF, UV–vis (for phthalocyanines),
1
H NMR.
In the IR spectra, the C^N stretching vibration band of phthaloni-
−
1
trile (3) at 2229 cm
exhibited. Other characteristic vibration bands
−1
3.2. Aggregation studies
were demonstrated at 3075 cm
for aromatic CeH stretching; be-
for aliphatic CeH stretching;
−
1
tween 2934 and 2835 cm
In this research paper, the aggregation behaviors of the peripheral
−
1
1
207–1142 cm for AreOeAr group stretching (see Fig. 1). When the
octa-substituted MPcs (Pc-Zn, Pc-Mg and Pc-Pb) were investigated in
1
H NMR spectrum taken in DMSO‑d
6
were examined, the protons of
various organic solvents such as chloroform (CHCl ), dichloromethane
3
aromatic ring of phthalonitrile compound (3) were exhibited among
(
CH
2
Cl ), dimethylformamide (DMF), dimethylsulphoxide (DMSO) and
2
7
3
.59–6.73 ppm, methoxy groups protons were observed 3.89–3.88 and
tetrahydrofurane (THF). This study was carried out to select a solvent
suitable to photocatalytic study. The absorption intensities of the Q
bands did not show significant changes in these solvents. When ag-
.74 ppm (see Fig. S1). Also, the mass spectra of phthalonitrile (3) was
measured by the MALDI–TOF spectral data and molecular ion peak was
+
noticed at m/z: 752.725 [M] (see Fig. 2).
II
gregation studies of these compounds were examined, the Zn (Pc-Zn),
When the infrared spectra of metal phthalocyanines was examined,
II
II
Mg (Pc-Mg) and Pb (Pc-Pb) phthalocyanines did not exhibit any
aggregation in all studied solvents on account of sharp Q band in-
tensities (see Fig. 3).
−
1
characteristic vibration bands were observed at 3066 cm (for Pc-Zn),
−
1
−1
3
066 cm
(for Pc-Mg) and 3061 cm (for Pc-Pb) for aromatic CeH
−
1
stretching; between 2930 and 2850 cm
−1
(for Pc-Zn),
(for Pc-Pb) for
The aggregation properties of the MPcs (Pc-Zn, Pc-Mg and Pc-Pb)
were investigated at different concentrations in DMF (see Fig. 4). When
the concentration augmented, the intensity of absorption of the Q band
also enhanced and no new band due to the formation of aggregated
species in DMF was observed. Beer–Lambert law was implemented for
all studied MPcs in the concentrations ranging from 1 μM–10 μM. The
studied MPcs (Pc-Zn, Pc-Mg andPc-Pb) did not exhibit any aggregation
at these concentration ranges in DMF.
−
1
2
930–2851 cm
(for Pc-Mg) and 2931–2842 cm
−
1
aliphatic CeH stretching; between 1267 and 1207–1176 cm (for Pc-
−
1
−1
Zn), 1268–1203–1176 cm
(for Pc-Mg) and1265–1206–1176 cm
1
(
for Pc-Pb) for AreOeAr group stretching (see Fig. 1). The H NMR
II
II
II
spectra of the obtained Zn (Pc-Zn), Mg (Pc-Mg) and Pb (Pc-Pb) were
registered in DMSO‑d and also these compounds demonstrated broad
6
absorptions when compared with the of corresponding phthalonitrile
1
derivative 3. In the H NMR spectra, the aromatic protons (AreH) and
]
CHe/eCH] bonds were indicated between 7.65 and 6.58 ppm for
3.3. Catalytic studies
(
Pc-Zn), 7.94–6.53 ppm for (Pc-Mg) and 7.61–6.61 ppm for (Pc-Pb),
also methoxy groups protons were showed between 3.66 ppm for (Pc-
Zn), 3.69 ppm for (Pc-Mg), 3.73 and 3.67 ppm for (Pc-Pb). The mass
II
II
II
Photocatalytic properties of Zn (Pc-Zn), Mg (Pc-Mg) and Pb (Pc-
Pb) were examined on 4-nitrophenol oxidation by photoreactor
Fig. 2. Mass spectra of phthalonitrile compound (3).
4

H. Yalazan, et al.
Inorganic Chemistry Communications 118 (2020) 107998
Fig. 3. UV–vis spectrums of metallophthalocyanines (Zn (Pc-Zn), Mg (Pc-Mg) and PbII (Pc-Pb)) in different solvents.
II
II
Fig. 4. UV–vis spectrums of metallophthalocyanines (ZnII (Pc-Zn), MgII (Pc-Mg) and PbII (Pc-Pb)) in different concentrations.
equipped with 8 pieces 16 W lamps at room temperature. The contents
of the samples that are taken from the reaction medium for 60 min were
examined by gas chromatography and product conversions were de-
not used during the photooxidation processes.
All reactions for finding optimal conditions of the photooxidation
were carried out with different 4-nitrophenol-to-catalysts molar ratios.
When the catalyst/substrate ratio was increased from 0.01/2000 to 1/
2000, the rate of the reaction increased. In contrast, while the catalytic
oxidation was processing from 1/2000 to 50/2000, the conversion fixed
II
II
II
termined as hydroquinone (42% for Pb (Pc-Pb), 30% for Zn (Pc-Zn)
II
II
and 6% for Mg (Pc-Mg)) and benzoquinone (48% for Pb (Pc-Pb),
II
II
2
3% for Zn (Pc-Zn) and 6% for Mg (Pc-Mg)). According to these
II
II
results, hydroquinone and benzoquinone were determined as reaction
products (see Fig. 5). When the same reactions were repeated at room
temperature in the dark, it was determined that the 4-nitrophenol
compound did not undergo any oxidation. Moreover, any oxidant was
to 90% for Pb (Pc-Pb) and 56% for Zn (Pc-Zn). Table 1 shows that Pb
(Pc-Pb) is good selectivity (58%) for degradation of 4-nitrophenol with
giving hydroquinone (42%) and benzoquinone (48%). Table 1 sum-
II
marizes all photocatalytic results with selectivity, TON value for Pb
II
(
Pc-Pb) and Zn (Pc-Zn). At the end of the photoxidation studies, the
amount of photodegradation of 4-nitrophenol was determined in the
presence of both photocatalysts. For this, the equation given below is
used.
Xt = Co
Ct/Co
In the above equation, X (t) is the molar fraction of 4-nitrophenol,
Co, initial concentration and C (t) is the concentration of 4-nitrophenol
as a function of illumination time. This equation shows a similar profile
Fig. 5. The oxidation products of 4-nitrophenol.
5

H. Yalazan, et al.
Inorganic Chemistry Communications 118 (2020) 107998
Table 1
Selective oxidation of 4-nitrophenol with catalyst Zn (Pc-Zn), Mg (Pc-Mg) and PbII (Pc-Pb).
II
II
o
Selectivitya (%)
PbPc
4
-nitrophenol/Catalyst
Temperature ( C)
Conversion (%)
TON
PbPc
ZnPc
MgPc
ZnPc
MgPc
PbPc
ZnPc
2
2
2
2
2
2
2
000/1
25
25
25
25
25
25
25
90
10
–
56
8
12
–
53
48
–
42
38
–
50
–
1500
166
933
000/free
000/1(in dark)
000/0.01
000/0.1
133
–
–
–
–
–
26
50
56
49
19
30
34
26
8
–
47
46
46
51
38
36
37
45
–
43,356
8337
933
31,683
5002
566
–
000/10
–
–
000/50
–
–
4085
2168
All photocatalytic reaction were done in photoreactor with light.
TON = mole of product / mole of catalyst.
TOF = mole of product / mole of catalyst × time.
Conversion was determined by GC.
−3
mol), catalyst (3.73 × 10−6 mol).
Reaction Conditions: solvent 10 mL DMF, 4-nitrophenol (6.22 × 10
a
=
Selectivity of benzoquinone Reaction time = 1 h.
in dark
PbPc
ZnPc
1
00
9
8
7
6
5
4
3
2
1
0
0
0
0
0
0
0
0
0
0
0
20
40
60
80
100
Time (min)
II
II
Fig. 6. The photocatalytic oxidation of 4-nitrophenol with near visible light irradiation Pb (Pc-Pb), Zn (Pc-Zn) and in dark. (A mixture of 4-nitrophenol
6.22 × 10 mol), catalyst (3.73 × 10 mol), and solvent (0.01 L) at 1 h.).
−
3
−6
(
to the photocatalytic degradation of other dyes [41,42]. For this pur-
pose, 100 mL of a 0.025 M solution of 4-nitrophenol and 5 mg of solid
catalyst were reacted in a photo-reactor under visible light (420 nm) for
1
h. During the photocatalytic reaction, all samples from the reaction
medium were diluted with dichloromethane and injected into the GC
apparatus. As a result, we observed that most of the 4-nitrophenol was
degraded and the rate of degradation was fixed after 60 min. Data on
photocatalytic degradation of 4-nitrophenol sensitized with both pho-
tocatalysts under visible light are presented in Fig. 6.
Cobalt (II), iron (II), aluminum (III), copper (II) and metal-free
phthalocyanines in which different groups have been substituted for the
photoxidation of different pollutants have been studied [43–49]. Nyo-
kong et al. studied the photocatalytic activity of seven octane sub-
stituted thio and aryloxy palladium and platinum phthalocyanines in
the breakdown of 4-nitrophenol [50]. According to the kinetic studies
of this study, two reaction pathways have been identified for the de-
gradation of 4-nitrophenol with phthalocyanine catalyst (see Fig. 7)
Fig. 7. Mechanism of 4-nitrophenol degradation.
[
51]. In another study by T. Nyokong, quantitative yields of singlet
oxygen and photodissection of 4-nitrophenol in the presence of zinc
tetrasulfiphthalocyanine (ZnPcS ), zinc octacarboxyphthalocyanine
ZnPcS4 (COOH) ) were investigated [51]. In the light of this literatures
ZnPc employees as photocatalyst with 56% product conversion and
2% benzoquinone selectivity. Zn is a divalent atom and may produce
singlet oxygen that degrades 4-nitrophenol [51]. On the other hand we
focused that metal centered phthalocyanines show good catalytic acti-
tivites with light for the oxidation of phenols. In the literature, although
many studies on the catalytic activities of phthalocyanine [52–57] are
available, only a few have examined photooxidation reactions using UV
radiation. Table 2 summarizes some of these literature. Our previous
4
(
8
4
6

H. Yalazan, et al.
Inorganic Chemistry Communications 118 (2020) 107998
Table 2
Declaration of Competing Interest
Catalytic activities of phthalocyanines in the photooxidation of different or-
ganic compounds in some previously reported catalyst.
The authors declare that they have no known competing financial
interests or personal relationships that could have appeared to influ-
ence the work reported in this paper.
Catalyst
Substrate
Rxn
Rxn
Oxidant Conv. (%) Ref.
Time
Temp.
o
(
h)
( C)
ZnTsPca
Acknowledgements
Methyl orange-
Orange G
10 min nr
9 h Rt
O
2
Nr
[44]
b
FePc
Ethyl benzene
Malachite green
2-
O
–
2
> 99
99.2
[45]
[46]
[47]
This study was supported by the Research Fund of Karadeniz
Technical University.
c
CoTNPc
30 min nr
d
e
CoPc
2
rt
–
nr
mercaptoethanol
f
Metal free Pc Sülfide ion
1
5
3
rt
O
–
2
2
2
70
[48]
[49]
[50]
Appendix A. Supplementary material
g
ı
h
CuPc
4-nitrophenol
27
rt
nr
CoPc
4-chlorophenol
O
99.99
97.05
88.0
Supplementary data to this article can be found online at https://
doi.org/10.1016/j.inoche.2020.107998.
ZnPcı
SiPcj
4-nitrophenol
3
rt
H
O
2
[56]
a
ZnTs-CoFerrite = 2-[5-(phenoxy)-isophthalic acid] 9(10), 16(17), 23(24)-tris
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