Synthesis, characterization and investigation of homogeneous oxidation activities of peripherally tetra-substituted Co(II) and Fe(II) phthalocyanines: Oxidation of cyclohexene

Article abstract of DOI:10.1016/j.molcata.2013.06.009

The synthesis and characterization of novel peripherally tetra-substituted iron(II) 4 and cobalt(II) 5 phthalocyanines are described for the first time in this study. All the new compounds are characterized by a combination of IR, ¹H and ¹³C NMR, mass and UV-vis spectroscopy techniques. Complexes 4 and 5 served as catalyst for the oxidation of cyclohexene using different types of oxidants, such as tert-butyl hydroperoxide (TBHP), m-chloroperoxybenzoic acid (m-CPBA), aerobic oxygen and hydrogen peroxide (H₂O₂). During the oxidation process the products formed are 2-cyclohexene-1-ol, 2-cyclohexene-1-one and cyclohexene oxide. The selectivity for 2-cyclohexene-1-ol is favored when iron(II) and cobalt(II) phthalocyanine catalysts are employed. The higher conversion is obtained as catalyst iron(II) phthalocyanine (96%). TBHP was determined as the successful oxidant with the minimum demolition of the catalyst, superior selectivity and conversion in the oxidation products.

Full text of DOI:10.1016/j.molcata.2013.06.009

Journal of Molecular Catalysis A: Chemical 378 (2013) 156–163
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Journal of Molecular Catalysis A: Chemical
journal homepage: www.elsevier.com/locate/molcata
Synthesis, characterization and investigation of homogeneous
oxidation activities of peripherally tetra-substituted Co(II) and Fe(II)
phthalocyanines: Oxidation of cyclohexene
Zekeriya Bıyıklıog˘lu∗, Ece Tug˘ba Saka, Serpil Gökc¸ e, Halit Kantekin
Department of Chemistry, Faculty of Science, Karadeniz Technical University, 61080 Trabzon, 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 novel peripherally tetra-substituted iron(II) 4 and cobalt(II) 5
phthalocyanines are described for the first time in this study. All the new compounds are characterized
by a combination of IR, 1H and 13C NMR, mass and UV–vis spectroscopy techniques. Complexes 4 and 5
served as catalyst for the oxidation of cyclohexene using different types of oxidants, such as tert-butyl
hydroperoxide (TBHP), m-chloroperoxybenzoic acid (m-CPBA), aerobic oxygen and hydrogen peroxide
(H2O2). During the oxidation process the products formed are 2-cyclohexene-1-ol, 2-cyclohexene-1-one
and cyclohexene oxide. The selectivity for 2-cyclohexene-1-ol is favored when iron(II) and cobalt(II)
phthalocyanine catalysts are employed. The higher conversion is obtained as catalyst iron(II) phthalo-
cyanine (96%). TBHP was determined as the successful oxidant with the minimum demolition of the
catalyst, superior selectivity and conversion in the oxidation products.
Received 7 March 2013
Received in revised form 6 May 2013
Accepted 17 June 2013
Available online xxx
Keywords:
Phthalocyanine
Iron
Cobalt
Cyclohexene
Oxidation
© 2013 Elsevier B.V. All rights reserved.
Tert-butyl hydroperoxide
1. Introduction
the oxidation products of cyclohexene and derivatives of cyclohex-
ene that present highly reactive carbonyl groups in cycloaddition
Phthalocyanines are a kind of N4-macrocycles known for their
very interesting industrial applications due to their high stabil-
ity, structural flexibility, diverse coordination properties, excellent
spectroscopic characteristics, and rich and reversible redox chem-
istry. Phthalocyanines have been extensively studied in many
applications such as catalysts, liquid crystals, electrochromic and
photochromic substances, data storage systems, photodynamic
cancer therapy agents, photoactive units, chemical sensors, and
nonlinear optical devices [1–3].
Due to ␲-stacking unsubstituted phthalocyanines are insolu-
ble in common organic solvents which limits the processability,
derivatization and the characterization of this type of compounds.
By introduction of bulky substituents at the ligand periphery
intermolecular interaction of the p systems can be reduced,
phthalocyanines become soluble and 13C NMR spectra are available
in common organic solvents. As a result, a variety of phthalonitriles
bearing alkyl, alkoxy and other functional groups have been syn-
thesized and employed in cyclotetramerization reactions [4–14].
In the oxidation of cyclohexene, transition metal complexes as
catalysts have attracted much attention in recent years, mainly for
reactions [15]. Of the currently available various ligands, remark-
able examples include porphyrin derivatives, phthalocyanine, and
Schiff base [16–19]. Among these substrates, metallophthalocya-
nine complexes are attractive oxidation catalysts and can be
prepared simply and cheaply for industrial applications. The cat-
alytic oxidation of cyclohexene is attracting attention because its
oxidation products (e.g. 2-cyclohexen-1-one, 2-cyclohexen-1-ol,
epoxide) are very useful synthetic intermediates [20].
Synthetic metalloporphyrins, that are similar structure as
cytochrome P-450, are highly efficient homogeneous and hetero-
geneous catalysts for cyclohexene oxidation by various oxidants
such as iodosylbenzene [21], hydrogen peroxide and tert-butyl
hydroperoxide [22]. The aerobic oxidation of olefins catalyzed by
metalloporphyrins and metallophthalocyanines is earning inter-
est from economic and environmental visions [23]. In addition,
cobalt(II) phthalocyanines have been used catalysts for the oxi-
dation of aromatic compounds [24]. Oxidation products of these
aromatic compounds are probably aldehyde, ketones and alcohols
that are commonly applied in the industrial factories and in the
scientific area. In this work, cyclohexene is handled as aromatic
compound and its oxidation products are stated as 2-cyclohexene-
1-one, 2-cyclohexene-1-ol and cyclohexene oxide. The oxidation
products of cyclohexene carry big value due to their usage in indus-
trial field and chemical workings. Because of the importance of both
∗
Corresponding author. Tel.: +90 462 377 3664; fax: +90 462 325 3196.
E-mail address: zekeriya 61@yahoo.com (Z. Bıyıklıog˘lu).
1381-1169/$ – see front matter © 2013 Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.molcata.2013.06.009

Z. Bıyıklıog˘lu et al. / Journal of Molecular Catalysis A: Chemical 378 (2013) 156–163
157
Fig. 1. The synthetic route of the phthalonitrile, cobalt phthalocyanine and iron phthalocyanine. Reagents and conditions: (i) EtOH, NaOH, 90 ◦C; (ii) dry DMF, K2CO3, 50 ◦C,
96 h; (ii) n-pentanol, DBU, 160 ◦C, Fe(CH3COO)2, CoCl2.
itself and its products, phthalocyanines with different substituted
groups (such as electron-acceptor groups such as halogenated and
phenyl groups) have been largely worked in oxidation of cyclohex-
ene [25].
[5.4.0]undec-7-ene (DBU) (0.4 ml) in 3 ml of n-pentanol and anhy-
drous Fe(CH3COO)2 (57 mg, 0.32 mmol) was heated and stirred at
160 ◦C for 12 h under N2. Then the reaction mixture was cooled pre-
cipitated by adding ethanol. The precipitated green solid product
was filtered off, and then dried in vacuo over P2O5. The obtained
green solid product was purified from the column chromatography
which is placed aluminum oxide using CHCl3/MeOH (100:1) as sol-
vent system. Yield: 122 mg (58%). IR (KBr pellet) ꢀmax/cm−1: 3068
(Ar H), 2922–2870 (Aliph. C H), 1607, 1573, 1498, 1448, 1399,
1339, 1276, 1232, 1126, 1078, 998, 958, 824, 746, 685. 1H NMR
(CDCl3), (ı:ppm): 7.56 (m, 8H, Ar H), 7.29 (m, 8H, Ar H), 6.45
(m, 12H, Ar H), 4.41 (m, 16H, CH2 O), 2.94 (s, 24H, CH3). UV–vis
(THF), ꢁmaks(log ε) nm: 603 (4.24), 652 (4.49). MS (ESI), (m/z): 1286
[M+H]+.
Fe(II) and Co(II) phthalocyanines are often used as oxidation
catalysts due to their oxygen transfer ability from various oxy-
gen donors to alkanes, alkenes, phenols and thiols in various
studies [26–37,25,38]. In this report, we report the synthesis
and characterization of {2-[3-(dimethylamino)phenoxy]ethoxy}
group-substituted iron and cobalt phthalocyanines 4 and 5. Addi-
tionally, it is also aimed that Fe(II) and Co(II) phthalocyanines 4 and
5 are used as catalysts for the oxidation of cyclohexene, with the
purpose of developing product selectivity and increasing the range
of products.
2. Experimental
2.1.2. Synthesis of cobalt(II) phthalocyanine (5)
Synthesized similarly to 4 from 3 by using anhydrous CoCl2.
Purification was achieved using column chromatography with
basic alumina as column material and chloroform:methanol
(100:3) solvent system as eluent. Yield: 160 mg (51%). IR (KBr
tablet) ꢀmax/cm−1: 3068 (Ar H), 2922–2870 (Aliph. C H), 1610,
1573, 1500, 1480, 1447, 1349, 1280, 1233, 1127, 1095, 1065, 998,
2.1. Synthesis
2.1.1. Synthesis of iron(II) phthalocyanine (4)
A mixture of 4-{2-[3-(dimethylamino)phenoxy]ethoxy}phtha-
lonitrile 3 (0.2 g, 0.65 mmol) and 0.65 mmol of 1.8-diazabicyclo

158
Z. Bıyıklıog˘lu et al. / Journal of Molecular Catalysis A: Chemical 378 (2013) 156–163
Fig. 2. UV–vis spectrum in THF for complexes 4 and 5. (For interpretation of the
references to color in this figure legend, the reader is referred to the web version of
this article.)
Fig. 3. UV–vis spectrum of iron(II) phthalocyanine 4 in different solvents (concen-
tration = 10 × 10−6 mol dm−3). (For interpretation of the references to color in this
figure legend, the reader is referred to the web version of this article.)
822, 751, 685. UV–vis (THF), ꢁmaks(log ε) nm: 333 (4.68), 605 (4.27),
668 (4.61). MS (ESI), (m/z): 1168 [M-C6H4-N(CH3)2]+.
in different solvents (CHCl3, CH2Cl2, THF, DMF, DMSO, EtOAc)
(Fig. 3 for complex 4). While iron phthalocyanine 4 showed little
aggregation in CHCl3, CH2Cl2, THF, DMF, EtOAc, DMSO showed full
aggregation. The absence of aggregated species in solution of 4 in
DMSO, DMF may be attributed to the axial coordination ability of
Fe(II) center. It is well known that the nature of solvent has a great
influence on the aggregation behavior of phthalocyanines [48,49].
On the other hand, the complex 5 showed little aggregation only in
EtOAc but cobalt phthalocyanine 5 did not show any aggregation
in CHCl3, CH2Cl2, THF, DMF, and DMSO.
3. Results and discussion
3.1. Synthesis and characterization
The synthesis route for the compounds is described in Fig. 1. In
this study, the initial phthalonitrile derivative 3 [39] was obtained
from the reaction between 2-[3-(dimethylamino)phenoxy]ethanol
1 and 4-nitrophthalonitrile 2 [40] in dry DMF at 50 ◦C [41,42]. Dry
K2CO3 was used to supply the basic reaction conditions. Cyclote-
tramerization of the phthalonitrile derivative 3 to the iron(II) and
cobalt(II) phthalocyanines 4 and 5 was accomplished in the pres-
ence of anhydrous Fe(CH3COO)2, CoCl2 in n-pentanol and DBU and
the crude product chromatographed on basic alumina. The struc-
The aggregation behavior of iron and cobalt phthalocyanine
complexes 4 and 5 were also investigated at different concen-
trations in DMSO. In DMSO, as the concentration increased, the
intensity of absorption of the Q band also increased and there were
no new bands (normally blue shifted) due to the aggregated species
for all phthalocyanines (Fig. 4 for complex 4). Beer–Lambert law
was obeyed for all of the compounds in the concentrations ranging
tures of the target compounds were confirmed using UV–vis, IR, 1
H
NMR, 13C NMR, MS spectroscopic data. The analyses are consistent
with the predicted structures as shown in Section 2.
from 12 × 10−6 to 2 × 10−6 mol dm−3
.
The IR spectrum of the iron and cobalt phthalocyanines 4
and 5 clearly indicates the cyclotetramerization of the phthaloni-
trile derivative 3 with the disappearance of the C N peak at
2232 cm−1, respectively. The 1H NMR spectrum of iron(II) phthalo-
cyanine 4 indicated the aromatic protons at 7.56, 7.29, 6.45 ppm
and aliphatic protons at 4.41, 2.94 ppm. The 1H NMR spectrum of
cobalt phthalocyanine 5 could not be taken due to the paramagnetic
cobalt(II) centers [43,44]. The mass spectra of tetra-substituted
phthalocyanines 4 and 5 confirmed the proposed structure, with
the molecular ion being easily identified at 1286 [M+H]+, 1168
[M−C6H4-N(CH3)2]+, respectively.
3.3. Catalytic studies
3.3.1. Oxidation of cyclohexene with 4 and 5
As shown in Tables 1–4, all oxidation experiments to evalu-
ate the catalytic effect of complexes 4 and 5 on the oxidation
of cyclohexene were performed under different reaction condi-
tions. Schlenk tube was filled with cyclohexene (1.16 × 10−3 mol),
complex 4 (3.88 × 10−6 mol) or complex 5 (3.89 × 10−6 mol) and
The metallophthalocyanines display typical electronic spectra
with two strong absorption regions, one of them in the UV region at
about 300–350 nm (B band) and the other one in the visible region
at 600–700 nm (Q band). The electronic absorption spectra of the
iron and cobalt phthalocyanines 4 and 5, in THF at room temper-
ature are shown in Fig. 2. UV–vis spectra of iron phthalocyanine
4 (in THF) split Q bands appeared at 652, 603 nm. UV–vis spectra
of cobalt phthalocyanine 5 (in THF) split Q bands appeared at 668,
605 nm, while the split B band remained at 333 nm.
3.2. Aggregation studies
Aggregation is usually depicted as a coplanar association of
rings progressing from monomer to dimer and higher order
complexes. It is dependent on the concentration, nature of the
solvent, nature of the substituents, complexed metal ions and
temperature [45–47]. In this study, the aggregation behavior of the
iron and cobalt phthalocyanine complexes 4 and 5 are investigated
Fig. 4. UV–vis spectrum of cobalt phthalocyanine 5 in DMSO at different concen-
trations, 12 × 10−6, 10 × 10−6, 8 × 10−6, 6 × 10−6, 4 × 10−6, 2 × 10−6 mol dm−3. (For
interpretation of the references to color in this figure legend, the reader is referred
to the web version of this article.)

Z. Bıyıklıog˘lu et al. / Journal of Molecular Catalysis A: Chemical 378 (2013) 156–163
159
O
OH
Oxidant
Catalyst (MPc)
O
Cyclohexene
2-cyclohexene-1-one
2-cyclohexene-1-ol
cyclohexenoxide
Fig. 5. Product formed through oxidation of cyclohexene by TBHP, m-CPBA and H2O2 in the presence of complexes 4 and 5.
TBHP (1.94 × 10−3 mol) in DMF (0.01 L) and refluxed at 90 ◦C with
900 rpm stirring in a typical catalytic reaction. The oxidation exper-
iments were done again with the oxidants without using complexes
4 and 5 as catalyst to prove significant of the catalyst in cyclo-
hexene oxidation. In Tables 1–4, the workings of the catalytic
activity of 4 and 5 were clearly demonstrated for oxidation of cyclo-
hexene. These workings in DMF show that both complexes are
successfully active catalysts in cyclohexene oxidation. At the end of
the cyclohexene oxidation, 2-cyclohexene-1-ol is observed as the
main product and 2-cyclohexen-1-one and cyclohexene epoxide as
minor product by using gas chromatography by both spotting and
comparison with standards (Fig. 5). Some parameters were studied
for getting maximum conversion of cyclohexene such as varying
the reaction temperature, time and different oxidants, subst./cat.
ratio.
Fig. 6a and b shows the variation of product yield with reac-
tion time. Among the oxidation products 2-cyclohexene-1-ol was
obtained with superior yield than the other both products. The con-
version from cyclohexene to these three products has increased
with the increasing time. But after 3 h, no yields of the products
were observed. This situation is probably due to the degradation of
the FePc and CoPc catalyst by oxidant, with time.
constant parameters were 90 ◦C, 1.94 × 10−3 mol TBHP, 0.01 L DMF
for 3 h. Table 1 demonstrates the experimental outcomes. As it is
seen, decreases in the substrate/catalyst molar ratio increases the
reaction rate. According to Table 1, both catalysts give same main
product (2-cyclohexene-1-ol) with selectivity of 65% for complex
4 and 60% for complex 5.
Catalytic activity of metallophthalocyanines and metallopor-
phyrins can be effected with replacing the central metal in the
oxidation reactions. Nam et al. used iron porphyrin with nitrate
or perchlorate as axial ligands with m-CPBA for the oxidation of
cyclohexene. They obtained cyclohexene oxide as main product
with yield (68–78%). On the other hand, same study was car-
ried out with chloride axial ligands, and not more than 2% yield
was obtained [50]. A few studies were also done with porphyrins.
More elevated yields of cyclohexene oxide were obtained by using
chloroperoxybenzoic acid and iodosylbenzene [51,52]. However,
photooxygenation of cyclohexene was achieved with titanium por-
phyrins, and cyclohexene hydroperoxide as a main product and
cyclohexene oxide as the side product were determined [53]. Addi-
tionally, 2-cyclohexene-1-ol was achieved as main product (55%
and 67%) with TBHP as oxidant and cobalt phthalocyanines as in
Ref. [54]. In our study, owing to the usage of complexes 4 and 5,
2-cyclohexene-1-ol was obtained main product with TBHP as an
oxidant.
For the influence of the substrate to iron(II) and cobalt(II)
phthalocyanines, the molar ratio was carried out in the range
of 300–1500 while other parameters were kept constant. The
To investigate the effect of oxidant type, different oxygen
sources were used on cyclohexene oxidation (TBHP, m-CPBA, aer-
obic oxygen and H2O2). Keeping the other parameters of the
oxidation experiments, only the amount of oxidant was changed.
The data are given in Table 2 and Fig. 7.
When H2O2 was immediately added to the reaction media, the
color of reaction solution of the 4 or 5 catalyst turned from the blue-
green color to colorless. This means that complexes 4 and 5 were
not employed as catalysts in the oxidation with H2O2. Thus, it can be
said that fast degradation of the phthalocyanine rings 4 and 5 was
observed with H2O2 as an oxidant. Moreover, degradation of the
phthalocyanine rings 4 and 5 was also determined with m-CPBA.
As TON values were compared, activity with m-CPBA (TON: 420) is
Fig. 6. Time-dependent conversion of cyclohexene oxidation for (a) catalyst 4 and
(b) catalyst 5.
Fig. 7. The oxidant effect on cyclohexene oxidation.

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Z. Bıyıklıog˘lu et al. / Journal of Molecular Catalysis A: Chemical 378 (2013) 156–163
Table 1
Amount of substrate effect of cyclohexene oxidation with complex 4 and 5.
Catalyst
Subs./Cat.
300/1
Alcohola
Ketoneb
Epoxidec
Tot. Conv. (%)
TONd
TOFe (h−1
)
4
5
65
60
20
12
11
8
96
80
288
240
96
80
4
5
600/1
60
53
18
12
11
8
89
75
534
450
178
150
4
5
900/1
53
50
14
11
6
7
73
68
657
612
219
204
4
5
1200/1
1500/1
41
36
14
8
5
5
60
49
720
588
240
196
4
5
35
28
10
4
3
4
48
36
720
541
240
180
a
2-Cyclohexene-1-ol.
2-Cyclohexene-1-one.
Cyclolohexenoxide.
Mole of product/mole of catalyst.
Mole of product/mole of catalyst × time.
b
c
d
e
Conversion was determined by GC.
Table 2
Different oxidant effect of cyclohexene oxidation with complex 4 and 5.
Catalyst
Oxidant
TBHP
Alcohola
Ketoneb
Epoxidec
Tot. Conv. (%)
TONd
TOFe (h−1
)
4
5
60
53
18
12
11
8
89
75
534
450
178
150
4
5
H2O2
22
21
12
10
9
7
43
38
258
228
86
76
4
5
m-CPBA
Free oxidant
49
41
15
7
6
3
70
51
420
306
140
102
4
5
–
–
–
–
–
–
–
–
–
–
–
–
a
2-Cyclohexene-1-ol.
2-Cyclohexene-1-one.
Cyclolohexenoxide.
Mole of product/mole of catalyst.
Mole of product/mole of catalyst × time.
b
c
d
e
Conversion was determined by GC.
higher than with H2O2 (TON: 258). When TBHP was used as oxygen
source on cyclohexene oxidation, complexes 4 and 5 show the con-
siderably exalted activity in the experimented oxidant (TON: 534
and 450 for catalysts 4 and 5). The checking studies demonstrate
that the cyclohexene cannot be oxidized without the oxidant.
Another important parameter effecting the results of catalysis
is the ratio of substrate/oxidant. As it is seen in Table 3, we investi-
gated the amount of oxidant by changing oxidant/catalyst ratio on
the cyclohexene oxidation while other parameters were constant.
Until the changing to 800/1, the oxidation rate raised but from this
ratio, total conversion leaned to declining. At this point, the coordi-
nation of the iron(II) and cobalt(II) may change and occur inactive
intermediate species.
In order to design the best catalytic system, the effect of differ-
ent temperatures was examined on the reaction rate of oxidation
of cyclohexene. Investigation of this parameter proved that as the
reaction temperature was increased the catalytic activity of com-
plexes 4 and 5 increased on the oxidation of cyclohexene. The
experiments were performed in the different temperatures (25, 50,
70, 90 ◦C) with ox./subst./cat. = 500/300/1 and TBHP, in DMF during
3 h (Table 4). The differences in the conversion was 46% for complex
4 and 34% for complex 5 when the temperature was raised from 25
to 90 ◦C. The highest conversion (96%) was obtained with TOF = 96
for complex 4 and (80%) with TOF = 80 for complex 5 at 90 ◦C. Based
on the results, temperature of the cyclohexene oxidation with both
complexes (molar ratio subs/ox/cat: 300/500/1) was determined as
90 ◦C.
Table 5 contains the oxidation studies in the literature. Based
on the performances of the Fe-Pc and Co-Pc catalysts 4 and 5
towards the cyclohexene oxidation, it can be said that they are more
successful catalysts than some other metallophthalocyanine and
metalloporphyrin catalysts. The best reported results are obtained
in terms of TOF in literature for homogeneous oxidation of cyclo-
hexene with TBHP as oxidant and FePc and Co-Pc as catalyst. FePc
was determined as successful catalyst on our study by comparing
with Co-Pc.
Lastly, we monitored the oxidation system by UV–vis spec-
troscopy in order to investigate the catalytic mechanism for the
metal-catalyzed cyclohexene in DMF and the results are illustrated
in Fig. 8. The UV–vis spectrum of metal–phthalocyanine (MPc) com-
plexes is commonly known and they consist of an intense band
called the Q band in the visible region [55]. The spectrum in Fig. 8
shows the typical spectrum of monomeric form of CoPc with a
Q band at 665 nm and also the electronic spectral change of this
catalyst during the process of the catalytic reaction in the pres-
ence of TBHP. The Q band shifts to 670 nm for complex 5 and
decreases in the intensity of the Q band. Because of the oxida-
tion state of metal ion from 2+ to 3+, the shift in the Q band is
observed [34]. In the B-band religion no peak can be observed.
Thus addition of TBHP to solutions of Co-Pc resulted in only metal
and not ring oxidation of Co-Pc. As catalysis continued, there
was a gradual decrease in the intensity of the Q band of the Co-
Pc catalyst, suggesting catalyst degradation as is typical [26] of
MPc catalysts in homogeneous catalysis. This degradation of the

Z. Bıyıklıog˘lu et al. / Journal of Molecular Catalysis A: Chemical 378 (2013) 156–163
161
Table 3
Amount of oxidant effect of cyclohexene oxidation with complex 4 and 5.
Catalyst
Oxidant/catalyst
500/1
Alcohola
Ketoneb
Epoxidec
Tot. Conv. (%)
TONd
TOFe (h−1
)
4
5
60
53
18
12
11
8
89
75
534
450
178
150
4
5
800/1
62
56
18
14
12
9
92
79
552
474
184
158
4
5
1000/1
1200/1
1500/1
52
50
15
12
9
7
76
69
456
414
152
138
4
5
46
41
10
10
7
5
63
56
378
336
126
112
4
5
38
32
9
7
4
4
51
43
306
258
102
86
a
2-Cyclohexene-1-ol.
2-Cyclohexene-1-one.
Cyclolohexenoxide.
Mole of product/mole of catalyst.
Mole of product/mole of catalyst × time.
b
c
d
e
Conversion was determined by GC.
Table 4
Temperature effect of cyclohexene oxidation with complex 4 and 5.
Catalyst
T (◦C).
Alcohola
Ketoneb
Epoxidec
Tot. Conv. (%)
TONd
TOFe (h−1
)
4
5
25
32
32
10
9
8
5
50
46
250
230
83
76
4
5
50
70
90
42
49
12
10
11
5
65
54
325
270
108
90
4
5
52
51
18
11
10
7
80
69
400
345
133
115
4
5
65
60
20
12
11
8
96
80
288
240
96
80
a
2-Cyclohexene-1-ol.
2-Cyclohexene-1-one.
Cyclolohexenoxide.
Mole of product/mole of catalyst.
Mole of product/mole of catalyst × time.
b
c
d
e
Conversion was determined by GC.
Table 5
Catalytic activities towards the homogeneous oxidation of cyclohexene of some previously reported catalyst.
Catalyst
Rxn time (h)
24
Rxn temp. (◦C)
rtg
Oxidant
O2
Conv. (%)
Ref.
[56]
a
Mn(tbpcH2
)
∼45
∼55
∼30
89
93
28
29
0
39
45.3
a
Fe(tbpcH2
Co(tbpcH2
Fe(TMPb)Cl
)
)
a
10 min
3
16
25
nrh
rtg
m-CPBA
PhIO
PhIO
[57]
[58]
[59]
Mn(PFTDCPPc)
MnTMpyP
FeTMpyP
MoTMpyP
MnTTAPP
Cl16FePcd
FePcd
nrh
75
8
TBHP
[26]
CoPcd
e
8
H2O2
O2
27.6
43.50
60
[60]
[61]
[62]
ˆ
ˆ
Co[NO]2 Cu[NO ]2
24
8
22
40
40
Cu(II)(l-prolinate)2
20
[Mn(Me2salpnMe2 f)]
[Co(Me2salpnMe2 f)]
[Cu(Me2salpnMe2 f)]
[Ni(Me2salpnMe2 f)]
Co(salen)–POM
TBHP
50.9
42.7
36.9
23.8
91
6
60
H2O2
[63]
a
Tetra-tert-butylphthalocyanine.
Meso-tetramesitylporphinato.
5-(Pentaflorophenyl)-10,15-20-tri(2,6-dichlorophenyl)porhrin.
Phthalocyanine.
2-Pyrazinecarboxylic acid.
N,N -Bis-(˛-methylsalicylidene)-2,2-dimethylpropane-1.
Room temperature.
Not reported.
b
c
d
e
f
g
h

162
Z. Bıyıklıog˘lu et al. / Journal of Molecular Catalysis A: Chemical 378 (2013) 156–163
a
b
c
d
e
Acknowledgement
1,4
1,2
1
This study was supported by The Scientific & Technological
Research Council of Turkey (TÜBITAK, project no: 111T963).
˙
Appendix A. Supplementary data
0,8
0,6
0,4
0,2
0
Supplementary data associated with this article can be
found, in the online version, at http://dx.doi.org/10.1016/j.molcata.
2013.06.009.
References
500
550
600
650
700
750
800
[1] N.B. McKeown, Phthalocyanine Materials: Synthesis, Structure and Function,
Cambridge University Press, Cambridge, 1998.
Wavelength (nm)
[2] F.H. Moser, A.L. Thomas, Properties, in: The Phthalocyanines, vol. 1, CRC Press,
Boca Raton, FL, 1983.
[3] C.C. Leznoff, A.B.P. Lever, Phthalocyanines Properties and Applications, VCH
Publishers, Weinheim, 1989.
[4] M. Hanack, H. Heckmann, R. Polley, Methods of Organic Chemistry, F: Aromatic
and Heteroaromatic Large Rings (Houben-Weyl), vol. 4, Thieme, Stuttgart,
1997, pp. 717–842.
[5] K.M. Kadish, K. Smith, M.R. Guilard, The Porphyrin Handbook, vol. 20, Elsevier
Science, San Diego, CA, USA, 2003.
Fig. 8. Time-dependent changes in the visible spectrum of the oxidized complex
5 observed on addition of. All spectra for the oxidized complex 5 were TBHP
(1.94 × 10−3 mol) to a reaction mixture containing 1.16 × 10−3 mol cyclohexene and
3.89 × 10−6 mol complex 5 catalyst in 10 ml: (b) 45 min; (c) 90 min; (d) 135 min; (e)
180 min after addition of TBHP taken after sixfold dilution with DMF. (a) The visible
spectrum of (non-oxidized) complex 5. (For interpretation of the references to color
in this figure legend, the reader is referred to the web version of this article.)
[6] R.P. Linstead, A.R. Lowe, J. Chem. Soc. 46 (1934) 1016–1018.
[7] N.B. McKeown, Science of Synthesis, vol. 17, Thieme, Stuttgart, 2003.
[8] Z. Bıyıklıog˘lu, A. Koca, H. Kantekin, Polyhedron 28 (2009) 2171–2178.
[9] Z. Bıyıklıog˘lu, H. Kantekin, I. Acar, Inorg. Chem. Commun. 11 (2008) 1448–1451.
[10] Z. Bıyıklıog˘lu, E.T. Güner, S. Topc¸ u, H. Kantekin, Polyhedron 27 (2008)
˙
catalysts is likely a consequence of RO• and ROO• radicals. These
radical species that are formed by oxidant (especially TBHP) easily
attack the phthalocyanine complex. This situation can easily realize
to observe changing reaction color. Before the catalysis, the color of
the solution was blue and then it turned to green as catalysis pro-
gressed. However, the reaction products continued to form even
after the catalyst had turned yellow, suggesting that once reaction
intermediates are formed, the reaction can still progress in the pres-
ence or absence of the original form of the catalyst. The mechanism
for Fe(II)Pc and Co(II)Pc transformation during the catalytic oxida-
tion of cyclohexene (ROOH THBP, m-CPBA, and H2O2).
1707–1713.
˙
[11] Z. Bıyıklıog˘lu, I. Acar, H. Kantekin, Inorg. Chem. Commun. 11 (2008) 630–632.
[12] H. Kantekin, Z. Bıyıklıog˘lu, E. C¸ elenk, Inorg. Chem. Commun. 11 (2008) 633–635.
[13] H. Kantekin, G. Dilber, Z. Bıyıklıog˘lu, J. Organomet. Chem. 693 (2008)
1038–1042.
˙
[14] I. Acar, Z. Bıyıklıog˘lu, A. Koca, H. Kantekin, Polyhedron 29 (2010) 1475–1484.
[15] P. Wu, T. Tatsumi, T. Komatsu, T. Yashima, J. Catal. 202 (2001) 245–255.
[16] A. Sakthivel, S.E. Dapurkar, P. Selvam, Appl. Catal. A: Gen. 246 (2003) 283–293.
[17] H. Kameyama, F. Narumi, T. Hattor, H. Kameyama, J. Mol. Catal. A: Chem. 258
(2006) 172–177.
[18] J.P.M. Niederer, W.F. Holderich, Appl. Catal. A: Gen. 229 (2002) 51–64.
[19] N. Sehlotho, T. Nyokong, J. Mol. Catal. A: Chem. 209 (2004) 51–57.
[20] Z. Bohstrom, I. Rico-Lattes, K. Holmberg, Green Chem. 12 (2010) 1861–1869.
[21] W. Adam, C. Mock-Knoblauch, C.R. Saha-Moller, M. Herderich, J. Am. Chem. Soc.
122 (2000) 11025–11026.
[22] N.A. Stephenson, A.T. Bell, J. Mol. Catal. A: Chem. 275 (2007) 54–62.
[23] O. Vakuliuk, F.G. Mutti, M. Lara, D.T. Gryko, W. Kroutil, Tetrahedron Lett. 52
(2011) 3555–3557.
[24] E.M. Gaigneaux, R. Maggi, P. Ruiz, B. Delmon, J. Mol. Catal. A: Chem. 109 (1996)
67–74.
.
.
-ROO , RO
ROOH
PcMII ROOH
PcMIII
PcMIII-O-IIIMPc
M: Co and Fe
[25] N. Grootboom, T. Nyokong, J. Mol. Catal. A: Chem. 179 (2002) 113–123.
[26] N. Sehlotho, T. Nyokong, J. Mol. Catal. A: Chem. 219 (2004) 201–217.
[27] B. Basu, S. Satapathy, A.K. Bhatnagar, Catal. Rev. Sci. Eng. 35 (1993) 571–609.
[28] M. Chibwe, L. Ukrainczyk, S.A. Boyd, T.J. Pinnavaia, J. Mol. Catal. A: Chem. 113
(1996) 249–256.
[29] S.M.S. Chauhan, B. Kalra, P.P. Mohapatra, J. Mol. Catal. A: Chem. 137 (1999)
85–92.
[30] V.M. Kothari, J.J. Tazuma, J. Catal. 41 (1976) 180–189.
[31] T. Ichinohe, H. Miyasaka, A. Isoda, M. Kimura, K. Hanabusa, H. Shirai, Funct.
Polym. 43 (2000) 63–70.
[32] T.V. Rao, K.N. Rao, S.L. Jain, B. Sain, Synth. Commun. 32 (2002) 1151–1157.
[33] M. Ozer, F. Yılmaz, H. Erer, I. Kani, Ö. Bekaroglu, Appl. Organomet. Chem. 23
(2009) 55–61.
[34] F. Zhao, J. Zhang, T. Abe, D. Wöhrle, M. Kaneko, J. Mol. Catal. A: Chem. 145 (1999)
245–256.
[35] H. Turk, Y. Cimen, J. Mol. Catal. A: Chem. 234 (2005) 19–24.
[36] Y. Cimen, H. Türk, Appl. Catal. A 340 (2008) 52–58.
[37] F. Yılmaz, M. Ozer, I. Kani, O. Bekarog˘lu, Catal. Lett. 130 (2009) 642–647.
[38] Y. C¸ imen, H. Türk, Appl. Catal. A: Gen. 340 (2008) 52–58.
[39] V. C¸ akır, F. Demir, Z. Bıyıklıog˘lu, A. Koca, H. Kantekin, Dyes Pigments 98 (2013)
414–421.
[40] J.G. Young, W.J. Onyebuagu, J. Org. Chem. 55 (1990) 2155–2159.
[41] Z. Bıyıklıog˘lu, M. Durmus¸ , H. Kantekin, J. Photochem. Photobiol. A: Chem. 211
(2010) 32–41.
4. Conclusion
We have presented the synthesis and characterization of a new
peripherally tetra-substituted Fe(II) and Co(II) phthalocyanines 4
and 5 using spectroscopic methods. The target symmetrical Fe(II)
and Co(II) phthalocyanines 4 and 5 were separated by column chro-
matography and characterized by a combination of UV–vis, IR, 1
H
NMR, 13C NMR, MS spectroscopic data. This work has determined
catalytic activities of Fe(II) and Co(II) phthalocyanines 4 and 5 on
cyclohexene oxidation. There are few reports about catalytic stud-
ies for Fe(II) and Co(II) phthalocyanines. The results show that
cyclohexene was converted to 2-cyclohexene-1-ol as major prod-
uct and 2-cyclohexen-1-one, cyclohexene oxide as minor products
with 96% and 80% with 4 and 5, respectively. The most promising
observation is that cyclohexenol is found to be major product in all
of the catalytic tests. Substrate effect, temperature effect and oxi-
dant effect were also discussed in this work. Control experiments
were done without catalyst precursor, the corresponding metal salt
as catalyst and we did not observe any product in the reaction mix-
ture. Iron(II) and cobalt(II) phthalocyanine complexes 4 and 5 were
also examined as catalyst for this reaction. Milder reaction condi-
tions, higher yields of the products, shorter reaction time, and more
inexpensive reagents make this catalytic system a useful oxidation
method for cyclohexene.
[42] Z. Bıyıklıog˘lu, M. Durmus¸ , H. Kantekin, J. Photochem. Photobiol. A: Chem. 222
(2011) 87–96.
˙
[43] I. Acar, R. Bayrak, E.T. Saka, Z. Bıyıklıog˘lu, H. Kantekin, Polyhedron 50 (2013)
345–353.
[44] Z. Bıyıklıog˘lu, Synth. Met. 161 (2011) 508–515.
[45] H. Yanık, D. Aydın, M. Durmus¸ , V. Ahsen, J. Photochem. Photobiol. 206 (2009)
18–26.
[46] M. Durmus¸ , M.M. Ayhan, A.G. Gürek, V. Ahsen, Dyes Pigments 77 (2008)
570–577.

Z. Bıyıklıog˘lu et al. / Journal of Molecular Catalysis A: Chemical 378 (2013) 156–163
163
[47] H. Engelkamp, R.J.M. Nolte, J. Porphyrins Phthalocyanines 4 (2000) 454–459.
[48] A. Alemdar, A.R. Özkaya, M. Bulut, Synth. Met. 160 (2010) 1556–1565.
[49] A.W. Snow, in: K.M. Kadish, K.M. Smith, R. Guillard (Eds.), The Porphyrin Hand-
book, vol. 17, Academic, San Diego, 2003, p. 129.
[56] K. Kasuga, T. Tsuboi, M. Handa, T. Sugimori, K. Sagobe, Inorg. Chem. Commun.
2 (1999) 507–509.
[57] M.H. Lim, S.W. Jin, Y.J. Lee, G.J. Jhon, W. Nam, C. Kim, Bull. Korean Chem. Soc.
22 (2001) 939–946.
[50] W. Nam, M.H. Lim, S.Y. Oh, J.H. Lee, S.K. Woo, C. Kim, W. Shin, Angew. Chem.
Int. Ed. 39 (2000) 3646–3649.
[58] G.D. Fabio, R.L.S. John, G.F. Antonio, D.A. Marilda, J. Mol. Catal. A: Chem. 164
(2000) 97–108.
[51] F.G. Doro, J.R.L. Smith, A.G. Ferreira, M.D. Assis, J. Mol. Catal. A: Chem. 164 (2000)
97–108.
[59] E.M. Serwickaa, J. Połtowicza, K. Bahranowskib, Z. Olejniczakc, W. Jones, Appl.
Catal. A: Gen. 275 (2004) 9–14.
[52] M.A. Schiavon, Y. Iamamoto, O.R. Nascimento, M.D. Assis, J. Mol. Catal. A: Chem.
174 (2001) 213–222.
[60] C. Pratap, K. Shigeru, K. Toshinori, S. Shigeo, Polyhedron 28 (2009)
370–380.
[53] P.E. Eser, B.D. Drießen-Hölscher, W. Keim, J. Mol. Catal. A: Chem. 140 (1999)
13–24.
[61] S. Goberna-Ferrón, V. Lillo, J.R. Galán-Mascarós, Catal. Commun. 23 (2012)
30–33.
[54] E.T. Saka, Z. Bıyıklıoglu, H. Kantekin, I. Kani, Appl. Organomet. Chem. 27 (2013)
59–67.
[62] M. Salavati-Niasari, P. Salemi, F. Davar, J. Mol. Catal. A: Chem. 238 (2005)
215–222.
[55] M.J. Stillman, T. Nyokong, in: C.C. Leznoff, A.B.P. Lever (Eds.), Phthalocyanines:
Properties and Applications, vol. 1, VCH, New York, 1989, p. 244.
[63] V. Mirkhani, M. Moghadam, S. Tangestaninejad, I. Mohammadpoor-Baltork, N.
Rasouli, Catal. Commun. 9 (2008) 2411–2416.