Light driven photodegradation of 4-nitrophenol with novel Co and Cu phthalocyanine in aqueous media

Article abstract of DOI:10.1016/j.molstruc.2020.128189

In this work, we have used two different metal centered water soluble phthalocyanines for the degradation of 4-nitrophenol in water media. In the photodegradation reactions that took place in the photoreactor for 1 h without using any oxidant, 4-nitrophenol compound was completed with 95% (for CoPc) and 97% (for CuPc) conversion to toxic and non-harmful species. The hydroquinone compound was identified as the main product and the benzoquinone compound as the by-product. The turnover number for Cu phthalocyanine was 1896 and for Co phthalocyanine was 2101. Finally, recovery studies were carried out for water soluble Cu phthalocyanine used as photocatalyst and the number of cycles was determined as 7.

Full text of DOI:10.1016/j.molstruc.2020.128189

Journal Pre-proof
Light driven photodegradation of 4-nitrophenol with novel Co and Cu phthalocyanine
in aqueous media
Ece Tugba Saka, Kader Tekintas
PII:
S0022-2860(20)30514-7
DOI:
https://doi.org/10.1016/j.molstruc.2020.128189
MOLSTR 128189
Reference:
To appear in: Journal of Molecular Structure
Received Date: 13 February 2020
Revised Date: 31 March 2020
Accepted Date: 1 April 2020
Please cite this article as: E. Tugba Saka, K. Tekintas, Light driven photodegradation of 4-nitrophenol
with novel Co and Cu phthalocyanine in aqueous media, Journal of Molecular Structure (2020), doi:
https://doi.org/10.1016/j.molstruc.2020.128189.
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CRediT authorship contribution statement
Ece Tugba Saka: Conceptualization, Formal analysis, Data curation, Funding acquisition,
Investigation,
Methodology,
Project
administration,
Resources,
Supervision,
Validation,Visualization, Writing - original draft, Writing - review&editing.
Kader Tekintas: Formal analysis, Data curation, Funding acquisition, Investigation, Methodology,
Writing - original draft, Writing - review&editing

Graphical Abstract

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Light Driven Photodegradation of 4-nitrophenol with Novel Co
and Cu Phthalocyanine in Aqueous Media
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Ece Tugba SAKA *a and Kader Tekintasa
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aDepartment of Chemistry, Faculty of Sciences, Karadeniz Technical University, 61080
Trabzon, Turkey
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In this work, we have used two different metal centered water soluble phthalocyanines for
the degradation of 4-nitrophenol in water media. In the photodegradation reactions that
took place in the photoreactor for 1 hours without using any oxidant, 4-nitrophenol
compound was completed with 95% (for CoPc) and 97% (for CuPc) conversion to toxic
and non-harmful species. The hydroquinone compound was identified as the main product
and the benzoquinone compound as the by-product. The turnover number for Cu
phthalocyanine was 1896 and for Co phthalocyanine was 2101. Finally, recovery studies
were carried out for water soluble Cu phthalocyanine used as photocatalyst and the
number of cycles was determined as 7.
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Keywords: Degradation, Light, Phthalocyanine; Cobalt; Copper; 4-nitrophenol.
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Corresponding author. Tel.: +90 462 377 2492; fax: +90 462 325 3196.
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E-mail address: ece_t_saka@hotmail.com (E.T. SAKA).
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1. Introduction
In recent decades, wastewater release from industries have unveiled a difficult issue of
environmental pollution. The wastewater/effluent released, particularly from the textile
industries, mostly contains organic dyes, that are hazardous to human health [1-2].
Therefore, it is very important to remove substituted phenols from aquatic environments,
but, it is not an easy task. Hence, the industries require an effective and cheap system or
method to tackle this issue. It is commonly known that many technologies such as
biodegradation, physical adsorption, and chemical oxidation methods have been used to
degrade these harmful chemicals into environment friendly materials [3–5]. Conventional
methods such as coagulation, microbial degradation, absorption on activated carbon,
biosorption, filtration and sedimentation have been used to treat the polluted water.
However, these methods may end up in producing incomplete degraded by products [6–8].
Recently, one of the most promising methods, photocatalytic degradation, was abundantly
applied in this type of application (water purification) due to its simplicity, mild reaction
conditions, low energy consumption, and more importantly it is an efficient method to
degrade the dyes completely into harmless compounds [9-11]. Nitrophenols, especially 4-
nitrophenol (4- NP), are classified as high toxic pollutants by the US Environmental
Protection Agency (USEPA) due to their chemical stability in the environment,
bioaccumulation, carcinogenicity, and toxicity [12]. The main uses of 4-NP are raw
materials or synthetic intermediates in the production of paracetamol drug, fungicides,
indicators, and leather preservative [13-14].
Phthalocyanine compounds become promising candidate as the metal centers as well as
nitrogen active sites are responsible for redox reactions that give rise to the pseudo
capacitive behavior [15-16]. Cobalt and copper Phthalocyanine (CoPc and CuPc), a
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transition metal complex catalysts with M-N4 active center, is one of the most promising
catalysts for this task owning to its high selectivity and activity of oxidation processes
[17–21].
In this study, the solubility in organic solvents with 4-pyridine-4-ylphenoxy groups and
conversion of these groups to quaternary derivatives provided solubility in water and
alcohol. It was aimed to design an ideal photocatalyst using a cheap and low cost metal
having different oxidation steps as the central atom in the phthalocyanine compound. The
photocatalytic activities of the water-soluble Co and Cu phthalocyanines were
investigated in the disintegration reaction of 4-nitrophenol which is an important
environmental pollutant and recovery studies of photocatalysts were performed.
2. Experimental
2.1. Materials
The used materials, equipments and general procedure of phthalonitrile precursor,
metallophthalocyanines and water soluble derivatives were supplied as supplementary
information.
2.2. Synthesis
2.2.1. Synthesis of 4-(pyridine-4-ylphenoxy)phthalonitrile 3
Yield: 900 mg (74%), m.p.: 193-195 ºC. IR (KBr pellet), νmax/cm-1: 3074, 3046 (Ar-H), 2987,
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2837 (Alifatik C-H), 2234 (C≡N), 1664, 1589, 1567, 1487, 1403, 1334, 1304, 1278, 1245,
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1204, 1173, 1083, 1030, 1017, 993, 950, 858, 811, 746, 669. H-NMR. (CDCl3), (δ:ppm):
8.33 (d, 2H, Ar-H), 8.06 (d, 2H, Ar-H), 7.85 (d, 2H, Ar-H), 7.63 (d, 2H, Ar-H), 7.51 (d, 2H,
Ar-H), 7.38 (d, 1H, Ar-H), 7.16 (d, 1H, Ar-H) 13C-NMR. (CDCl3), (δ:ppm): 158.10 (ArC-N),
155.17 (ArC-N), 148.07 (ArC), 146.25 (ArC), 138.11 (ArC), 135.13 (ArC), 130.60 (ArC),
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127.43 (ArC), 124.52 (ArC), 123.03 (ArC), 121.03 (ArC), 120.33 (ArC), 117.25 (C≡N),
116.77 (C≡N), 110.56 (ArC),
MALDI-TOF-MS, (m/z): Hesaplanan: 297.31; Bulunan:
298.40 [M+H]+.
2.2.2. Synthesis of Cobalt(II) phthalocyanine (4)
Yield: 820 mg (45%), M.p. >300oC. IR (KBr pellet), νmax/cm-1: 3092, 3058 (Ar-H), 2978,
2912 (Alifatik C-H), 1597, 1510, 1475, 1403, 1382, 1354, 1282, 1248, 1243, 1172, 1091, 951,
813, 746, 708. UV-Vis (CHCI3): λmax, nm (log ε): 680 (4.68), 608 (4.62), 308 (4.57).
MALDI-TOF-MS, (m/z): Calculated: 1248.17; Found: 1249.20 [M+H]+. Solubility: CHCl3,
CH2Cl2, DMF, DMSO.
2.2.3. Synthesis of Copper(II) phthalocyanine (5)
Yield: 780 mg (43%), M.p. >300oC. IR (KBr pellet), νmax/cm-1: 3090, 3037 (Ar-H), 2981,
2942, 2856 (Alifatik C-H), 1580, 1523, 1482, 1426, 1391, 1363, 1292, 1273, 1213, 1182,
1051, 991, 853, 846, 735, 608. UV-Vis (CHCI3): λmax, nm (log ε): 712 (4.70), 618 (4.45),
324(4.66). MALDI-TOF-MS, (m/z): Calculated: 1252.78; Found: 1252.62 [M]+. Solubility:
CHCl3, CH2Cl2, DMF, DMSO.
2.2.4. Synthesis of Water Soluble Cobalt(II) phthalocyanine (4a)
Yield: 35 mg (83%), m.p. > 300 °C. IR (ATR) ν (cm−1): 3008 (Ar-H), 2931–2870 (Aliph.
CeH), 1607, 1473, 1343, 1322, 1281, 1232, 1114, 1096, 1051, 1016, 973, 949, 893, 827, 746.
UV–Vis (water) λmax nm (log ε): 692 (5.06), 614 (4.62), 329 (4.06). MALDI-TOF-MS m/z
calc. 1815.78; found: 327.04 [M-4I]+4.
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2.2.5. Synthesis of Water Soluble Copper(II) phthalocyanine (5a)
Yield: 35 mg (83%), m.p. > 300 °C. IR (ATR) ν (cm−1): 3008 (Ar-H), 2931–2870 (Aliph. C-
H), 1607, 1473, 1343, 1322, 1281, 1232, 1114, 1096, 1051, 1016, 973, 949, 893, 827, 746.
UV–Vis (water) λmax nm (log ε): 669 (5.02), 635 (4.72), 336 (5.02). MALDI-TOF-MS m/z
calc. 1820.39; found: 328.19 [M-4I]+4.
2.3. Photooxidation Studies
The photocatalytic activity of water soluble Co and Cu phthalocyanine on photooxidation
reactions of the 4-nitrophenol compound using a photoreactor during the catalysis processes
will be examined. For the photooxidation study in which water is used as the solvent, firstly a
specified amount of substrate, a calculated amount of catalyst and a total of 10 ml of solvent
will be added to the Schlenk container. The reaction time was determined as 1 hours. This
point will be taken as the starting time of the reaction by taking some sample from the
reaction medium by pipetting into the glass tube. When the specified reaction time is
completed, the samples taken from the reaction vessel will be analyzed on a gas
chromatography device and the time dependent change profile of the product will be obtained.
119 3. Results and discussion
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3.1. Synthesis and characterization
Figure 1 and 2 shows the common synthesis routes for the novel phthalonitrile 3,
peripheral substituted non-ionic cobalt and copper phthalocyanines (4 and 5) and their
quaternized derivatives (4a and 5a). 4-pyridine-4-ylphenol was reacted with 4-
nitrophtahlonitrile giving the novel phthalonitrile 3 in the presence of dry K2CO3 in
dehydrated DMF. After the purification of phthalonitrile 3 by crystallization, the non-ionic
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cobalt and copper 4 and 5 were prepared using metal salts [CoCl2 or CuCl2] and phthalonitrile
3 in dry 1- hexanol and 1,8-Diazabicyclo(5.4.0)undec-7-ene. Quaternized ionic cobalt and
copper phthalocyanines 4a and 5a were prepared by the reaction of non-ionic Pcs 4 and 5 with
methyl iodide in chloroform. The synthesized non-ionic Pcs are soluble in DMF and DMSO;
moreover they displayed great solubility in aqueous media after quaternization. The novel
compounds were described by MALDI-TOF, FT-IR and UV-Vis spectroscopies. Whole
spectroscopic data were compatible with the predicted structure of the compounds. The C=N
frequency of the pyridine ring was seemed at 1589 cm−1 and C≡N vibration peak at 2234
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cm−1. The H NMR spectra of 3 in CDCl3 was presented aromatic proton signals around at
8.33–7.16 ppm for compound 3 as doublet, triplet or double doublet in accordance with the
structure. The molecular ion peak seen at m/z = 298.40 [M+H]+ also proved the structures of
phthalonitrile 3. After conversion of the phthalonitrile 3 into non-ionic Pc complexes (4 and
5), the missing strong nitrile (C≡N) vibration peaks is the sign of the genesis of the Pcs. Due
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to Co+2 and Cu+2 are paramagnetic metals, H-NMR spectra of 4 and 5 cannot be taken [22-
23]. Molecular ions of the non-ionic (4 and 5) and quaternized ionic (4a and 5a) Pcs were
simply detected at m/z: 1249.20 [M+H]+ for 4, 1252.62 [M]+ for 5, 327.04 [M-4I]+4 for 4a and
328.19 [M-4I]+4 for 5a.
In substituted Pc complexes, characteristic two strong absorption bands are detected: Q band
at around 600–700 nm (in the visible region) and B band at around 300–350 nm (in the UV
region). Studied non-ionic Pc complexes 4 and 5 and their quaternized ionic derivatives 4a
and 5a showed Q bands as intense and single between 680 nm for 4, 712 nm for 5 in
chloroform (Figure 3). In Figure 4, 692 nm for 4a and 669 nm for 5a in water.
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3.2. Catalytic Studies
Photocatalytic properties of water soluble Co and Cu phthalocyanines 4a and 5a were
examined on 4-nitrophenol oxidation by photoreactor equipped with 8 pieces 16W lamps at
room temperature. The contents of the samples that are taken from the reaction medium for 60
minutes were examined by gas chromatography and product conversions were determined.
According to these results, hydroquinone was determined as the main product and
benzoquinone as the by-product (Figure 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 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 to 95% for
4a and 97% for 5a. Table 1 shows that 5a is good selectivity (%74) for degradation of 4-
nitrophenol with giving hydroquinone (71%) and benzoquinone (26%). Table 1 summarizes
all photocatalytic results with selectivity, TON and TOF values for 4a and 5a. At the end of
the photooxidation studies, the amount of photodegradation of 4-nitrophenol was determined
in the presence of both photocatalysts 4a and 5a. For this, the equation given below is used.
X(t) = Co- C(t)/ 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 to the photocatalytic degradation of other dyes
[24-25]. For this purpose, 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 for 1 hours. During the
photocatalytic reaction, all samples from the reaction medium were diluted with
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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 minutes. Data on
photocatalytic degradation of 4-nitrophenol sensitized with both photocatalysts under visible
light are presented in Figure 6.
Recycling studies have been carried out considering the importance of recyclability of
photocatalysts for the environment. For this application, water-soluble copper phthalocyanine
compound 5a was used as photocatalyst. 100 ml of 0.015 M 4-nitrophenol solution, 5 mg of
compound 5a were treated with UV irradiation in the photoreactor for 60 minutes. At the end
of each reaction, the catalyst was removed by extraction with water 3 times and made ready
for use in the new photooxidation reaction. It was determined that photocatalytic activity
gradually decreased from 97% to 80.3% in reuse and 72% in 7th time use. This reduction can
be explained by the fact that the phthalocyanine compound 5a also degrades during
photooxidation and forms different species. As a result, compound 5a gives 72% yield
conversion even after 7 cycles (Figure 7).
Cobalt (II), iron (II), aluminum (III), copper (II) and metal-free phthalocyanines in
which different groups have been substituted for the photooxidation of different pollutants
have been studied [26-32]. Nyokong et al. studied the photocatalytic activity of seven octane
substituted thio and aryloxy palladium and platinum phthalocyanines in the breakdown of 4-
nitrophenol [33]. According to the kinetic studies of this study, two reaction pathways have
been identified for the degradation of 4-nitrophenol with phthalocyanine catalyst (Figure
8)[33]. In another study by T. Nyokong, quantitative yields of singlet oxygen and
photodissection of 4-nitrophenol in the presence of zinc tetrasulfiphthalocyanine (ZnPcS4),
zinc octacarboxyphthalocyanine (ZnPcS4 (COOH) 8) were investigated [34]. In the literature,
although many studies on the catalytic activities of phthalocyanine [35-40] are available, only
a few have examined photooxidation reactions using UV radiation. Table 2 summarizes some
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of these literature. My previous work clearly shows that silicone phthalocyanine employes
effective catalyst (88% product conversion) in 4-nitrophenol oxidation with H2O2 [41]. But in
this study, it is the first time in this field to investigate the photooxidation of 4-nitrophenol
using novel water soluble cobalt and copper phthalocyanine as photocatalyst without any
oxygen source in aqueous media. The results of photocatalytic experiments can generate
promising new research and micro-scale application.
4. Conclusion
In the study, peripherally 4-pyridine-4-ylphenoxy groups substituted cobalt and copper
phthalocyanine 4 and 5 and its water-soluble quaternized derivatives 4a and 5a were
synthesized for the first time and their structures were illuminated by spectroscopic data.
Compounds 4a and 5a used as photocatalysts in the photooxidation reaction of 4-nitrophenol,
an important environmental pollutant, yielded 95% and 97% yield conversion, respectively.
Hydroquinone (main product) was obtained as benzoquinone (by-product) in the product
distribution. The high conversion of 4-nitrophenol into non-toxic species by photooxidation
makes the study important. The high product conversion and selectivity of the obtained
photocatalysts in homogeneous and heterogeneous solvent systems makes this study
innovative in terms of shedding light on new studies on developing environmentally cleaner
and more efficient systems.
Acknowledgment
This study was supported by the Research Fund of Karadeniz Technical University, (Project
no: 7687), Trabzon-Turkey.
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References
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[1] M.D Hernando, S.D. Vettori, M.J.M. Bueno, A.R.F. Alba, Toxicity evaluation
with Vibrio fischeri test of organic chemicals used in aquaculture, Chemosphere 68 (2007)
724-730.
[2] R. Jain, M. Mathur, S. Sikarwar, A. Mittal, Removal of the hazardous dye rhodamine B
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
through photocatalytic and adsorption treatments, J. Environ. Manage. 85 (2007) 956-964.
[3] M. Derudi, G. Venturini, G. Lombardi, G. Nano, R. Rota, Biodegradation combined with
ozone for the remediation of contaminated soils, Eur. J. Soil Biol. 43 (2007) 297-303.
[4] A.L. Ahmad, S.W. Puasa, Reactive dyes decolourization from an aqueous solution by
combined coagulation/micellar-enhanced ultrafiltration process, Chem. Eng. J. 132 (2007)
257-265.
[5] J.H. Mo, Y.H. Lee, J. Kim, J.Y. Jeong, J. Jegal, Treatment of dye aqueous solutions using
nanofiltration polyamide composite membranes for the dye wastewater reuse, Dyes Pigm. 76
(2008) 429-434.
[6] A. Roy, M. Pradhan, C. Ray, R. Sahoo, S. Dutta, T. Pal, Facile synthesis of pyridine
intercalated ultra-long V2O5 nanowire from commercial V2O5: catalytic applications in
selective dye degradation, Cryst. Eng. Comm. 16 (2014) 7738-7744.
[7] O. Hamdaoui, Intensification of the sorption of Rhodamine B from aqueous phase by
loquat seeds using ultrasound, Desalination 271 (2011) 279-286.
[8] W.L. Zhang, Y. Li, C. Wang, P.F. Wang, Kinetics of heterogeneous photocatalytic
degradation of rhodamine B by TiO2-coated activated carbon: Roles of TiO2 content and light
intensity, Desalination 266 (2011) 40-45.
[9] K. Rajeshwar, A. Thomas, C. Janaky, Photocatalytic Activity of Inorganic Semiconductor
Surfaces: Myths, Hype, and Reality, J. Phys. Chem. Lett. 6 (2015) 139-147.
10

11
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
[10] S. Adhikari, D. Sarkar, G. Madras, Hierarchical Design of CuS Architectures for Visible
Light Photocatalysis of 4-Chlorophenol, ACS Omega 2 (2017) 4009-4021.
[11] J.S. Kumar, P. Thangadurai, Enhanced visible-light-driven photodegradation of Rh-6G
by surface engineered Pd-V2O5 heterostructure nanorods, Journal of Environmental
Chemical Engineering 6 (2018) 5320-5331.
[12] A.F.T. Substances & D. Registry, Public Health Service (1992).
[13] Z. Xiong, H. Zhang, W. Zhang, B. Lai, G. Yao, Removal of nitrophenols and their
derivatives by chemical redox: A review, Chemical Engineering Journal 359 (2019) 13-31.
[14] M. Dinari, F. Dadkhah, Swift reduction of 4-nitrophenol by easy recoverable magnetite-
Ag/layered double hydroxide/starch bionanocomposite, Carbohydrate Polymers 228 (2020)
115392.
[15] K.P. Madhuri, N.S. John, Supercapacitor application of nickel phthalocyanine nanofibres
and its composite with reduced graphene oxide, Appl. Surf. Sci. 449 (2018) 528-536.
[16] R. Ramachandran, Q. Hu, F. Wang, Z.X. Xu, Synthesis of N-CuMe2Pc
nanorods/graphene oxide nanocomposite for symmetric supercapacitor electrode with
excellent cyclic stability, Electrochim. Acta 298 (2019) 770-777.
[17] E.T. Saka, Z. Bıyıklıoğlu, H. Kantekin, Microwave-assisted synthesis and
characterization of Co(II) phthalocyanine and investigation of its catalytic activity on 4-
nitrophenol oxidation, Turkish Journal of Chemistry 38 (2014) 1166-1173.
[18] E.T. Saka, S. Uzun, Y. Çağlar, Synthesis, structural characterization, catalytic activity on
aerobic oxidation of novel Co(II) and Fe(II) phthalocyanines and computational studies of 4-
[2-(2,3-dichlorophenoxy)ethoxy]phthalonitrile, Journal of Organometallic Chemistry 810
(2016) 25-32.
11

12
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
[19] E.T. Saka, Y. Çağlar, New Co(II) and Cu(II) Phthalocyanine Catalysts Reinforced by
Long Alkyl Chains for the Degradation of Organic Pollutants, Catalysis Letters 147 (2017)
1471-1477.
[20] A. Aktaş, I. Acar, E.T. Saka, Z. Bıyıklıoğlu, H. Kantekin, Fluoro functional groups
substituted cobalt(II), iron(II) phthalocyanines and their catalytic properties on benzyl alcohol
oxidation, Journal of Inclusion Phenomena and Macrocyclic Chemistry 3-4 (2016) 183-190.
[21] E.T. Saka, G. Sarkı, H. Kantekin, Facile synthesis of highly active Co(II) and Fe(II)
phthalocyanine catalysts for aerobic oxidation of phenolic compounds, Journal of
Coordination Chemistry 68 (2015) 1132-1141.
[22] H.Z. Gök, M.K. Yılmaz, Peripherally 1,2-dinaphthyl ethanediol substituted
phthalocyanine complexes: synthesis, characterization, aggregation, and application in benzyl
alcohol oxidation at room temperature, Turkish Journal of Chemistry 43 (2019) 1017-1029.
[23] E.N. Kaya, A. Senocak, D.D. Klyamer, E. Demirbas, T.V. Basova, M. Durmus,
Ammonia sensing performance of thin films of cobalt(II) phthalocyanine bearing fluorinated
substituents, Journal of Materials Science: Materials in Electronics 30 (2019) 7543-7551.
[24] I. Altın, M. Sokmen, Z. Bıyıklıoglu, Quaternized zinc (II) phthalocyanine-sensitized
TiO2: surfactant-modified sol–gel synthesis, characterization and photocatalytic applications,
Desalination and Water Treatment 57 (2016) 16196-16207.
[25] R. Bayrak, C. Albay, M. Koç, I. Altın, İ. Degirmenci, M. Sokmen, Preparation of
phthalocyanine/TiO2 nanocomposites for photocatalytic removal of toxic Cr (VI) ions,
Process Safety and Environmental Protection 102 (2016) 294-302.
[26] S. Mapukata, N. Kobayashi, M. Kimura, T. Nyokong, Asymmetrical and symmetrical
zinc phthalocyanine-cobalt ferrite conjugates embedded in electrospun fibers for dual
photocatalytic degradation of azo dyes: Methyl Orange and Orange G, Journal of
Photochemistry and Photobiology A: Chemistry 379 (2019) 112-122.
12

13
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
[27] W.L. He, C.D. Wu, Incorporation of Fe-phthalocyanines into a porous organic
framework for highly efficient photocatalytic oxidation of arylalkanes, Applied Catalysis
B:Environmental 234 (2018) 290-295.
[28] M. Lu, B. Li, Y. Zhang, Q. Liang, X. Li, S. Xu, Z. Li, Facile synthesis and
characterization of a cobalt phthalocyanine sensitized SnIn4S8 composites toward enhanced
photocatalytic activity, J. Mater. Sci. 29 (2018) 16680-16690.
[29] P. Arunachalam, S. Zhang, T. Abe, M. Komura, T. Iyoda, K. Nagai, Weak visible light
(∼mW/cm2) organophotocatalysis for mineralization of amine, thiol and aldehyde by biphasic
cobalt phthalocyanine/fullerene nanocomposites prepared by wet process, Applied Catalysis
B:Environmental 193 (2016) 240-247.
[30] V. Iliev, D. Tomova, Photocatalytic oxidation of sulfide ion catalyzed by phthalocyanine
modified titania, Catalysis Communications 3 (2002) 287-292.
[31] G. Mele, R. Del Sole, G. Vasapollo, E. García-López, L. Palmisano, M. Schiavello,
Photocatalytic degradation of 4-nitrophenol in aqueous suspension by using polycrystalline
TiO2 impregnated with functionalized Cu(II)–porphyrin or Cu(II)–phthalocyanine, Journal of
Catalysis 217 (2003) 334-342.
[32] Y. Mahmiani, A.M. Sevim, A. Gül, Photocatalytic degradation of 4-chlorophenol under
visible light by using TiO2 catalysts impregnated with Co (II) and Zn (II) phthalocyanine
derivatives, Journal of Photochemistry and Photobiology A: Chemistry 321 (2016) 24-32.
[33] T.B. Ogunbayo, E. Antunes, T. Nyokong, Investigation of homogeneous photosensitized
oxidation activities of palladium and platinum octasubstituted phthalocyanines: Oxidation of
4-nitrophenol, Journal of Molecular Catalysis A: Chemical, 334 (2011) 123-129.
[34] E. Marais, R. Klein, E. Antunes, T. Nyokong, Photocatalysis of 4-nitrophenol using zinc
phthalocyanine complexes, Journal of Molecular Catalysis A: Chemical 261 (2007) 36-42.
13

14
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
[35] A.A. Kamıloglu, I. Acar , Z. Bıyıklıoglu, E.T. Saka, Peripherally tetra-{2-(2,3,5,6-
tetrafluorophenoxy)ethoxy} substituted cobalt(II), iron(II) metallophthalocyanines: Synthesis
and their electrochemical, catalytic activity studies, Journal of Organometallic Chemistry 828
(2017) 59-67.
[36] A.A. Kamıloglu, I. Acar , E.T. Saka, Z. Bıyıklıoglu, Synthesis of polyfluoro substituted
Co(II), Fe(II) phthalocyanines and their usage as catalysts for aerobic oxidation of benzyl
alcohol, Journal of Organometallic Chemistry 815-816 (2016) 1-7.
[37] V. Cakır, E.T. Saka, Z. Bıyıklıoglu, H. Kantekin, Highly selective oxidation of benzyl
alcohol catalyzed by new peripherally tetra-substituted Fe(II) and Co(II) phthalocyanines,
Synthetic Metals 197 (2014) 233-239.
[38] A.A. Kamıloglu, E.T. Saka, Z. Bıyıklıoglu, I. Acar, H. Kantekin, Investigation Of
Catalytic Activity Of New Co(Ii) Phthalocyanine Complexes In Cyclohexene Oxidation
Using Different Type Of Oxidants, Journal of Organometallic Chemistry 745-746 (2013) 18-
24.
[39] Z. Bıyıklıoglu, E.T. Saka, S. Gökçe, H. Kantekin, Synthesis, characterization and
investigation of homogeneous oxidation activities of peripherally tetra-substituted Co(II) and
Fe(II) phthalocyanines: Oxidation of cyclohexene, Journal of Molecular Catalysis
A:Chemical 378 (2013) 156-163.
[40] E.T. Saka, G. Sarkı, H. Kantekin and A. Koca, Electrochemical, spectroelectrochemical
and catalytical properties of new Cu(II) and Co(II) phthalocyanines, Synthetic Metals 214
(2016) 82-91.
[41] E.T. Saka, H. Yalazan, Z. Bıyıklıoglu, H. Kantekin, K. Tekintas, Synthesis, aggregation,
photocatalytical and electrochemical properties of axially 1-benzylpiperidin-4-oxy units
substituted silicon phthalocyanine, Journal of Molecular Structure 1199 (2020) 126994.
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15
349
350
351
Table 1. Selective oxidation of p-nitrophenol with catalyst 4a and 5a
4-nitrophenol/Catalyst
Temperature (oC)
Conversion (%)
Selectivitya (%)
TON
4a
95
5a
97
4a
51
5a
74
4a
1896
5a
2102
2000/1
25
25
2000/free
12
8
32
45
6
-
4
2000/1(in dark)
2000/0.01
25
25
4
52
6
59
-
38
-
51
-
10400
15800
9600
11800
2000/0.1
2000/10
2000/50
25
25
25
79
48
28
80
60
44
44
33
22
67
45
37
16000
12000
17600
11200
352
353
354
355
356
357
All photocatalytic reaction were done in photoreactor with light.
TON = mole of product / mole of catalyst
TOF= mole of product / mole of catalyst x time
Conversion was determined by GC.
Reaction Conditions: solvent (water), 4-nitrophenol (5.49×10-3 mol), catalyst (2.75×10-6 mol),
a=Selectivity of hydroquinone Reaction time=1 hours.
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
15

16
381
382
Table 2. Catalytic activities of phthalocyanines in the photooxidation of different organic compounds
in some previously reported catalyst.
Catalyst
Substrate
Rxn
Rxn Temp.
(oC)
Oxidant
Conv.
(%)
Ref.
Time
(h)
ZnTsPca
FePcb
Methyl orange-
Orange G
10min
nr
rt
O2
O2
-
nr
[27]
[28]
[29]
[30]
Ethyl benzene
Malachite green
2-mercaptoethanol
9h
30 min
2
>99
99.2
nre
CoTNPc c
CoPcd
nr
rt
-
Metal free Pcf
CuPcg
Sülfide ion
4-nitrophenol
4-chlorophenol
1
5
3
rt
27
rt
O2
-
70
[31]
[32]
[33]
nrh
CoPcı
ZnPcı
O2
99.99
97.05
SiPcj
4-nitrophenol
H2O2
88.0
[39]
3
rt
383
384
385
386
387
388
389
390
391
392
ZnTs-CoFerritea= 2-[5-(phenoxy)-isophthalic acid] 9(10), 16(17), 23(24)-tris (tertbutyl) phthalocyaninato Zn (II)
FePc-POFb= four-branched tetra-amine FePc-porous organic framework
CoTNPc/SnIn4S8 c = Tetranitrocobalt phthalocyanine/ ternary chalcogenide
CoPcd=Cobaltphthalocyanine/C60
Metal free Pcf=Metal free phthalocyanine/TiO2
CuPcg=Copper phthalocyanine/ TiO2
CoPcı= 2,9,16,23-tetrakis-(4-carboxyphenylsulphanyl) phthalocyaninato cobalt(II) / TiO2
ZnPcı= 2,9,16,23-tetrakis-(4-carboxyphenylsulphanyl) phthalocyaninato zinc(II) / TiO2
SiPcj= 1-benzylpiperidin-4-oxy substituted silicone phthalocyanine
nr= not reported
16

17
393
394
395
396
nre=Turnover number is given as 8.4
nrh=Quantum yield is given as 1.9
397
398
399
400
401
402
403
404
405
406
407
408
Figure Captions:
Figure 1. The synthetic route of the phthalonitrile, cobalt phthalocyanine and copper
phthalocyanine. Reagents and conditions: (i) dry DMF, K2CO3, 60°C, 96 h; (ii) n-pentanol,
DBU, 160 °C, CoCl2, CuCl2.
Figure 2. Synthetic route of water soluble Co and Cu phthalocyanines
Figure 3. UV-Vis Spectrum of complex 4 and 5 in chloroform.
Figure 4. UV-Vis Spectrum of complex 4a and 5a in water.
Figure 5. The oxidation products of 4-nitrophenol.
Figure 6. The photocatalytic oxidation of p-nitrophenol with near visible light irradiation 4a,
5a and in dark. (A mixture of 4-nitrophenol (5.49×10-3 mol), catalyst (2.75×10-6 mol), and
water (0.01 L) at 1 h.)
409
410
411
412
413
414
415
416
417
418
Figure 7. Recycle experiments of compound 5a in 4-nitrophenol oxidation. Reaction
conditions: 5.49×10-3 mol 4-nitrophenol, 2.75×10-6 mol compound 5a and water as solvent
(0.01 L).
Figure 8. Mechanism of 4-nitrophenol degradation
17

18
419
420
421
422
N
OH
1
CN
i
O2N
CN
2
CN
CN
3
ii
N
N
N
N
N
M
N
N
N
=
N
M= Co (4), Cu (5)
423
424
425
426
427
428
429
430
431
Figure 1. The synthetic route of the phthalonitrile, cobalt phthalocyanine and copper
phthalocyanine. Reagents and conditions: (i) dry DMF, K2CO3, 60°C, 96 h; (ii) n-pentanol,
DBU, 160 °C, CoCl2, CuCl2.
18

19
+4
RO
OR'
OR
OR'
N
N
N
N
N
N
CH3-
M
N
N
M
N
N
4
CHCl3, rt
N
N
N
N
N
N
RO
OR
OR'
OR'
M= Co(4a), Cu(5a)
M=Co(4a), Cu(5a)
N
R=
N
R'=
432
433
434
Figure 2. Synthetic route of water soluble Co and Cu phthalocyanines
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
19

20
453
454
455
456
1,2
1
4
5
0,8
0,6
0,4
0,2
0
300
400
500
600
700
800
Wavelength (nm)
457
458
459
460
461
462
463
464
465
466
467
468
Figure 3. UV-Vis Spectrum of complex 4 and 5 in chloroform.
20

21
469
470
471
472
473
Figure 4. UV-Vis Spectrum of complex 4a and 5a in water.
474
475
476
477
478
479
21

22
480
481
Figure 5. The oxidation products of 4-nitrophenol.
482
483
484
485
486
487
488
489
490
491
492
22

23
in dark
5a
4a
100
90
80
70
60
50
40
30
20
10
0
0
20
40
60
80
100
Time (min)
493
494
Figure 6. The photocatalytic oxidation of p-nitrophenol with near visible light irradiation 4a,
5a and in dark. (A mixture of 4-nitrophenol (5.49×10-3 mol), catalyst (2.75×10-6 mol), and
water (0.01 L) at 1 h.)
495
496
497
498
499
500
501
502
503
504
505
23

24
506
100
90
80
70
60
50
40
30
20
10
0
Conversion (%)
Selectivity (%)
1
2
3
4
5
6
7
Cycle number of compound 5a
507
508
509
510
511
512
513
Figure 7. Recycle experiments of compound 5a in 4-nitrophenol oxidation. Reaction
conditions: 5.49×10-3 mol 4-nitrophenol, 2.75×10-6 mol compound 5a and water as solvent
(0.01 L).
514
515
516
517
518
519
520
521
522
523
524
24

25
525
526
527
528
529
530
-
O
O
hv
MPc
NO2
O
4-Nitrophenol
Benzoquinone
MPc
hv
-
-
O
OH
O
.
OH
.
NO2
.
.
OH
Hydroquinone
531
532
Figure 8. Mechanism of 4-nitrophenol degradation
533
25

Highlights of manuscripts
•
Photocatalytic activity of Co and Cu phthalocyanines and their water soluble
derivatives.
•
•
Hydroquinone and benzoquinone are products of 4-nitrophenol photodegradation.
Recovery studies were carried out for water soluble Cu phthalocyanine used as
photocatalyst.
1

Declaration of interests
☐The authors declare that they have no known competing financialinterestsor personal relationships
that could have appeared to influence the work reported in this paper.
☐The authors declare the following financial interests/personal relationships which may be considered
as potential competing interests: