Binuclear iron(III) octakis(perfluorophenyl)tetraazaporphyrin μ-oxodimer: A highly efficient catalyst for biomimetic oxygenation reactions

Article abstract of DOI:10.1016/j.tetlet.2014.08.070

Binuclear iron(III) octakis(perfluorophenyl)tetraazaporphyrin μ-oxodimer complex was prepared by the reaction of bis(perfluorophenyl)maleonitrile and Fe(CO)₅and tested in catalytic oxygenation reactions of several hydrocarbons in comparison with the analogous non-fluorinated phthalocyanine complexes. Results of the study demonstrate that this complex is a highly efficient catalyst for the oxygenation of anthracene, 2-tert-butylanthracene, naphthalene, 2-methylnaphthalene, phenanthrene, adamantane, and toluene using iodosylbenzene, oligomeric iodosylbenzene sulfate, or Oxone as stoichiometric oxidants.

Full text of DOI:10.1016/j.tetlet.2014.08.070

Accepted Manuscript
Binuclear iron(III) octakis(perfluorophenyl)tetraazaporphyrin μ-oxodimer: a
highly efficient catalyst for biomimetic oxygenation reactions
Mekhman S. Yusubov, Cumali Celik, Margarita R. Geraskina, Akira
Yoshimura, Viktor V. Zhdankin, Victor N. Nemykin
PII:
S0040-4039(14)01413-0
DOI:
http://dx.doi.org/10.1016/j.tetlet.2014.08.070
TETL 45037
Reference:
To appear in:
Tetrahedron Letters
Received Date:
Revised Date:
Accepted Date:
1 August 2014
17 August 2014
18 August 2014
Please cite this article as: Yusubov, M.S., Celik, C., Geraskina, M.R., Yoshimura, A., Zhdankin, V.V., Nemykin,
V.N., Binuclear iron(III) octakis(perfluorophenyl)tetraazaporphyrin μ-oxodimer: a highly efficient catalyst for
biomimetic oxygenation reactions, Tetrahedron Letters (2014), doi: http://dx.doi.org/10.1016/j.tetlet.2014.08.070
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Binuclear iron(III) perfluoro(tetraazaporphyrin) µ-
oxodimer: a highly efficient catalyst for biomimetic
oxygenation reactions
Leave this area blank for abstract info.
Mekhman S. Yusubov∗, Cumali Celik, Margarita R. Geraskina, Akira Yoshimura, Viktor V. Zhdankin∗ and Victor N.
Nemykin∗

1
Tetrahedron Letters
journal homepage: www.els evier.com
Binuclear iron(III) octakis(perfluorophenyl)tetraazaporphyrin µ-oxodimer: a highly
efficient catalyst for biomimetic oxygenation reactions
a,
b,c
b
Mekhman S. Yusubov ∗, Cumali Celik , Margarita R. Geraskina , Akira Yoshimura , Viktor V.
b
b,
Zhdankin ∗ and Victor N. Nemykin ∗
b,
a
Tomsk Polytechnic University and Siberian State Medical University, 634050 Tomsk, Russian Federation
b
Department of Chemistry and Biochemistry, University of Minnesota Duluth, 1039 University Dr., Duluth, Minnesota 55812, USA
c
Yalova University, Yalova Community College, 77200, Yalova, Turkey
ARTICLE INFO
ABSTRACT
Article history:
Received
Binuclear iron(III) octakis(perfluorophenyl)tetraazaporphyrin µ-oxodimer complex was
prepared by the reaction of bis(perfluorophenyl)maleonitrile and Fe(CO) and tested in catalytic
5
Received in revised form
Accepted
oxygenation reactions of several hydrocarbons in comparison with the analogous non-
fluorinated phthalocyanine complexes. Results of the study demonstrate that this complex is a
highly efficient catalyst for oxygenation of anthracene, 2-tert-butylanthracene, naphthalene, 2-
methylnaphthalene, phenanthrene, adamantane, and toluene using iodosylbenzene, oligomeric
iodosylbenzene sulfate, or Oxone as stoichiometric oxidants.
Available online
Keywords:
oxygenation
2
009 Elsevier Ltd. All rights reserved.
catalytic oxidation
phthalocyanines
tetraazaporphyrin
Transition-metal porphyrins, phthalocyanines, and related
compounds are widely used as catalysts in the reactions
mimicking natural oxidations performed by the heme-containing
commercially available catalyst which has a relatively high
resistance toward oxidative degradation. However, the resistance
of
5,10,15,20-tetrakis(pentafluorophenyl)porphyrin
toward
1
cytochrome P-450 class of enzymes. It has also been
2
oxidative degradation is limited due to the presence of C–H
bonds in the four pyrrole units of the porphyrine ring. In present
communication, we describe the preparation and catalytic activity
of the first example of a transition-metal fully fluorinated
tetraazaporphyrin complex, the binuclear iron(III) octakis-
(perfluorophenyl)tetraazaporphyrin µ-oxodimer 1 (Figure 1),
which does not have any C–H bonds in its structure and exhibits
an exceptional resistance to oxidative degradation.
a-c
demonstrated that porphyrin and phthalocyanine iron µ-oxo-,
2
d-f
and µ-nitridodimers,
which were earlier considered as
catalytically inactive compounds, have high catalytic activity in
different oxidation reactions. In particular, iron phthalocyanine-
(µ-oxodimer) complexes have been found to be active catalysts
in biomimetic oxygenations of aromatic hydrocarbons using
iodosylbenzene, 2-iodylbenzoate ester, and oligomeric
4
iodosylbenzene sulfate (PhIO) SO , as terminal oxidants.
3 3
Complex 1 was synthesized using direct high-temperature
reaction between bis(perfluorophenyl)maleonitrile and Fe(CO)
(see experimental details in Supplementary Material).
In spite of the high catalytic activity, synthetic application of
iron(III) phthalocyanine(µ-oxodimer)complexes is limited due to
their low stability toward oxidative degradation under reaction
conditions. It is known that the introduction of fluorine atoms
into the molecule significantly increase stability of the porphyrin
5
Catalytic activity of perfluoro(tetraazaporphyrin) complex 1
towards oxygenations of aromatic hydrocarbons was investigated
in comparison with the analogous non-fluorinated phthalocyanine
2a-c,4
moiety;
tetrakis(pentafluorophenyl)porphyrin is a well known,
for
example,
5,10,15,20-
complexes 2 and 3.
The results of catalytic oxidations of
anthracene 4, 2-tert-butylanthracene 7, naphthalene 9, 2-
methylnaphthalene 11, phenanthrene 16, adamantane 18 and
—
——
∗
Corresponding author.
E-mal address: vzhdanki@d.umn.edu
Fax: 1-218-726-7394

2
Tetrahedron Letters
toluene using iodosylbenzene or oligomeric iodosylbenzene
5
sulfate as sources of oxygen and catalyst 1 are summarized in
Table 1.
The complete conversion of a less reactive substrate, 2-tert-
butylanthracene 6, to give product 7 was reached in 1 hour in
At first, a set of preliminary experiments was performed to
test the appropriate amount of catalyst needed for efficient
oxygenation of anthracene, which is the most commonly used
aromatic substrate for catalytic oxygenations (Table 1, entries 1-
CH
catalyst 1 (1 mol%) and oligomeric iodosylbenzene sulfate,
(PhIO) SO , as the more reactive source of oxygen (entries 6 and
7). A similar oxygenation with catalyst 2 (15 mol%) and PhIO
2 2
Cl using catalyst 1 (5 mol%) and PhIO or in 6 min with
3
3
4c
3
). The oxidation of anthracene 4 was carried out in dry
requires 20 hours at room temperature (entry 8). Likewise, the
oxygenation of naphthalene 8 and 2-methylnaphthalene 10 with
the catalyst 1/PhIO system proceeds very fast with the low
catalyst loading of 1-2 mol%, which is much more efficient
compared to catalyst 2 (entries 9-11). The oxidation of 2-
methylnaphthalene 10 gives a mixture of products 11 and 12,
which is in agreement with the previously reported oxygenations
dichloromethane with complex 1 and PhIO (10 equiv) under
stirring at room temperature. Samples of the reaction mixture
were collected at every 5 minutes, filtered through silica gel,
washed with a mixture of ethyl acetate and hexanes (2:3, v:v),
and analyzed by GC-MS. This study has demonstrated that the
oxygenation of anthracene with
a 100% conversion to
2
,6
anthraquinone 5 was observed when 2 mol% of catalyst 1 was
used with full conversion of the substrate in 2 hours (entry 3).
For comparison, 10 mol% of catalyst is required for a similar
oxygenation using phthalocyanine-(µ-oxodimer) complexes 2
and 3 (entries 4 and 5).
of this substrate.
Even more impressive results were obtained in the
oxygenation of the least reactive aromatic substrate,
phenanthrene 13, to give product 14 (entries 12 and 13). A
complete oxygenation of phenanthrene with 2 mol% of catalyst 1
occurs in 2 hours, while no reaction is observed in the presence
of catalyst 2 (15 mol%).
In contrast with the non-fluorinated catalysts 2 and 3, iron(III)
octakis(perfluorophenyl)tetraazaporphyrin µ-oxodimer 1 is an
3
efficient catalyst for the oxidation of C–H bonds at sp -
hybridized carbon. When adamantane 15 was used as a substrate
with 2 mol% of catalyst 1, the mixture of products 1-
adamantanol 16 and 2-adamantanone 17 was obtained in high
yield (entry 14). For comparison, no reaction was observed with
catalyst 2 (entry 15), and only 2.4% conversion was achieved in
24 hours with catalyst 3 (15 mol%) giving 1-adamantanol as the
product (entry 16).
Figure 1. Binuclear iron(III) perfluoro(tetraazaporphyrin) µ-oxodimer 1.
The oxidation of toluene in the presence of catalyst 1 (5
mol%) gave a mixture of oxygenated products (mainly, quinone
1
8) with a 100% conversion in 30 min (entry 17). This is an
impressive proof of high reactivity of catalyst 1, as toluene
previously has been commonly used as a nonreactive organic
solvent for similar metalloporphyrin-catalyzed oxygenation
reactions (cf. entry 18).
Figure 2. Iron(III) phthalocyanine-(µ-oxodimer) complexes 2 and 3.
Table 1. Catalytic activity of iron(III) octakis(perfluorophenyl)tetraazaporphyrin 1 in oxygenation reactions in comparison with
phthalocyanine complexes 2 and 3.
Entry
Catalyst
mol%)
Substrate
Time to 100%
conversion (h)
Product distribution (%)
(
1
1 (10)
0.5
2
3
1 (5)
1 (2)
2 (10)
3 (10)
1 (5)
4
4
4
4
1
2
5
2
1
5 (100%)
5 (100%)
5 (100%)
5 (100%)
b
4
c
5
6
d
7
1 (1)
6
6
0.1
20
7 (100%)
7 (100%)
e
8
2 (15)

3
9
1 (2)
1
f
1
0
1 (1)
0.3
e
1
1
1
2
2 (30)
1 (2)
10
24
2
11 (55%) + 12 (45%)
e
f
1
1
3
4
2 (15)
1 (2)
13
-
none
1
g
1
1
1
5
6
7
2 (15)
3 (15)
1 (5)
15
-
none
c,d
15
24
16 (2.4%) + 15 (97.6%)
PhCH
3
0.5
g
-
1
8
2 (30)
PhCH
3
none
a
b
c
d
e
f
Reactions were performed in dichloromethane at room temperature using iodosylbenzene (10 equiv) as source of oxygen unless otherwise noted.
4c
Toluene was used as solvent; data from literature.
4c
Methanol was used as solvent; data from literature.
Oligomeric iodosylbenzene sulfate, (PhIO)
3
3
SO , was used as source of oxygen.
4c
Toluene was used as solvent and (PhIO) SO
3
3
as source of oxygen; data from literature.
The presence of several regioisomeric products of hydroxylation was also detected by GC-MS in this reaction.
g
4c
No reaction observed under these conditions in the presence of catalyst 2.
.
Table 2. Oxygenations of 2-tert-butylanthracene 6 in the
a
presence of catalyst 1 with different oxidants.
Time (min)
At the next step, we investigated oxygenations in the presence
Entry
Oxidant
Conversion
of catalyst 1 and different common oxidants (oligomeric
iodosylbenzene sulfate, Oxone, peracetic acid, hydrogen
peroxide) in aqueous acetonitrile using 2-tert-butylanthracene 6
as the standard substrate (Table 2). 2-tert-Butylanthracene was
selected because it is oxidized relatively slow, probably due to
the steric hindrance caused by the tert-butyl group, selectively
producing anthraquinone 7 as a single product (Table 1, entries
of 6 to 7
1
2
3
(PhIO)
Oxone
3
SO
3
5
100
100
44
5
CH CO H/CH CO H
3
3
3
2
1440
4320
4
30% aq H
2
O
2
0
6-8). The oxygenation of 2-tert-butylanthracene 6 in dry
dichloromethane with catalyst 1 (1 mol%) using oligomeric
iodosylbenzene sulfate gives 100% conversion in 6 minutes
a
Reactions were performed in acetonitrile-water (1:1) at room temperature
with terminal oxidant (6 equiv of active O) and 0.5 mol% of catalyst 1.
(
entry 7). The same reaction in acetonitrile-water (1:1) mixture
requires even smaller quantity of catalyst 1 (0.5 mol%) to give
00% conversion in 5 minutes (Table 2, entry 1). Oxone
2KHSO •KHSO •K SO ) has about the same reactivity as
These results demonstrate that oligomeric iodosylbenzene
sulfate and Oxone are the most powerful oxidants in the iron(III)
octakis(perfluorophenyl)tetraazaporphyrin-catalyzed
oxygenations. In order to further compare reactivity of these two
oxidants, we measured the number of oxygenation cycles that can
be performed using the same initial quantity of catalyst 1 (0.5
mol%) and adding 1 equiv of substrate 6 and excessive oxidant
1
(
5
4
2
4
oligomeric iodosylbenzene sulfate (entry 2), whereas peracetic
acid and hydrogen peroxide are not efficient sources of oxygen in
these reaction (entries 3 and 4).

4
Tetrahedron
(
6 equiv of active O) several times, until conversion of 6 to 7
Government of Russia for support of our cooperative research
program (Russian Science Foundation No. 14-43-
00005)
and the Ministry of Education and Science of Russian
Federation (project "Science" No. 4.2569.2014/K).
falls below 100% and this value stays unchanged (Table 3).
These data in principle allow us to compare stability of the
catalyst toward oxidative degradation in the presence of different
oxidants under reaction conditions.
References and notes
Table 3. Oxygenation cycles in the reactions of 2-tert-
butylanthracene 6 with different oxidants in the presence of
1
.
Representatives books and reviews: (a) Cytochrome P450:
Structure, Mechanism, and Biochemistry; Ortiz de Montellano, P.
R., Ed.; Kluwer Academic/Plenum Publishers: New York, 2005;
(b) Metalloporphyrins in Catalytic Oxidations; Sheldon, R. A.,
Ed.; M. Dekker: New York, 1994; (c) Meunier, B. Chem. Rev.
1992, 92, 1411-1456; (d) Simonneaux, G.; Tagliatesta, P. J.
Porphyrins Phthalocyanines 2004, 8, 1166-1171; (e) Rose, E.;
Andrioletti, B.; Zrig, S.; Quelquejeu-Etheve, M. Chem. Soc. Rev.
a
fixed quantity of catalyst 1 (0.5 mol%).
Entry Oxidant
Cycle
Time (min)
Conversion
of 6 to 7
st
1 addition
1
2
3
4
5
6
7
8
9
1
(PhIO)
(PhIO)
(PhIO)
(PhIO)
(PhIO)
(PhIO)
(PhIO)
(PhIO)
Oxone
Oxone
Oxone
3
3
3
3
3
3
3
3
SO
3
SO
3
SO
3
SO
3
SO
3
SO
3
SO
3
SO
3
5
100
100
100
100
100
100
100
99
nd
2
3
4
5
6
7
8
1
2
3
addition
addition
addition
addition
addition
addition
addition
addition
addition
addition
5
2
005, 34, 573-583; (f) Bernadou, J.; Meunier, B. Adv. Synth.
rd
th
th
th
th
th
st
10
20
20
40
90
240
5
Catal. 2004, 346, 171-184; (g) Vinhado, F. S.; Martins, P. R.;
Iamamoto, Y. Curr. Top. Catal. 2002, 3, 199-213; (h) Meunier,
B.; Robert, A.; Pratviel, G.; Bernadou, J. Porphyrin Handbook
2000, 4, 119-187; (i) Groves, J. T.; Shalyaev, K.; Lee, J.
Porphyrin Handbook 2000, 4, 17-40; (j) Ji, L.; Peng, X.; Huang, J.
Progress in Natural Science 2002, 12, 321-330; (k) Groves, J. T.
J. Porphyrins Phthalocyanines 2000, 4, 350-352; (l) Kimura, M.;
Shirai, H. Porphyrin Handb. 2003, 19, 151-177; (m) Nemykin, V.
N.; Lukyanets, E. A. Handbook of Porphyrin Science, 2010, 3, 1-
323; (n) Nemykin, V. N.; Lukyanets, E. A. J. Porph.
Phthalocyan., 2010, 14, 1-40; (o) Nemykin, V. N.; Lukyanets, E.
A. ARKIVOC, 2010, (i), 136-208.
100
100
75
2
.
(a) Zalomaeva, O. V.; Kholdeeva, O. A.; Sorokin, A. B. C. R.
Chim. 2007, 10, 598-603; (b) Kholdeeva, O. A.; Zalomaeva, O.
V.; Sorokin, A. B.; Ivanchikova, I. D.; Della Pina, C.; Rossi, M.
Catal. Today 2007, 121, 58-64; (c) Sorokin, A. B.; Mangematin,
S.; Pergrale, C. J. Mol. Catal. A: Chem. 2002, 182-183, 267-281;
nd
rd
0
1
30
1440
1
a
Reactions were performed in acetonitrile-water (1:1) at room temperature
using the same initial quantity of catalyst 1 (0.5 mol%) and adding 1 equiv of
substrate 6 and excessive oxidant (6 equiv of active O) several times, until
conversion of 6 to 7 falls below 100%.
(
d) Kudrik, E. V.; Sorokin, A. B. Chem. Eur. J. 2008, 14, 7123-
126; (e) Sorokin, A. B.; Kudrik, E. V.; Bouchu, D. Chem.
7
Commun. 2008, 2562-2564; (f) Kudrik, E. V.; Afanasiev, P.;
Bouchu, D.; Millet, J.-M. M.; Sorokin, A. B. J. Porphyrins
Phthalocyanines 2008, 12, 1078-1089. (g) Sorokin, A. B. Chem.
Rev. 2013, 113, 8152-8191.
These data (Table 3) demonstrate that iron(III)
octakis(perfluorophenyl)tetraazaporphyrin µ-oxodimer 1 (0.5
mol%) can work highly efficiently up to 8 cycles in the oxidizing
system 2-tert-butylanthracene 6 - oligomeric iodosylbenzene
sulfate in acetonitrile-water (1:1) solvent system (entry 8). Oxone
is a less efficient oxidant affording after the third addition only
3
4
.
.
Yusubov, M. S.; Nemykin, V. N.; Zhdankin, V. V. Tetrahedron
2
(a) Geraskin, I. M.; Luedtke, M. W.; Neu, H. M.; Nemykin, V. N.;
Zhdankin, V. V. Tetrahedron Lett. 2008, 49, 7410-7412; (b)
Geraskin, I. M.; Pavlova, O.; Neu, H. M.; Yusubov, M. S.;
Nemykin, V. N.; Zhdankin, V. V. Adv. Synth. Catal. 2009, 351,
010, 66, 5745-5752.
7
5% conversion in 24 hours (entry 11). This experiment clearly
7
33-737; (c) Neu, H. M.; Yusubov, M. S.; Zhdankin, V. V.;
indicates that oligomeric iodosylbenzene sulfate is at least twice
more efficient oxidant than Oxone, and has a substantial
advantage over Oxonein this oxidizing system.
Nemykin, V. N. Adv. Synth. Catal. 2009, 351, 3168-3174; (d)
Yoshimura, A.; Neu, H. M.; Nemykin, V. N.; Zhdankin, V. V.
Adv. Synth. Catal. 2010, 352, 1455-1460.
5
6
.
.
(a) Nemykin, V. N.; Koposov, A. Y.; Netzel, B. C.; Yusubov, M.
S.; Zhdankin, V. V. Inorg. Chem. 2009, 48, 4908-4917; (b)
Koposov, A. Y.; Netzel, B. C.; Yusubov, M. S.; Nemykin, V. N.;
Nazarenko, A. Y.; Zhdankin, V. V. Eur. J. Org. Chem. 2007,
In conclusion, we have reported the preparation and catalytic
activity
octakis(perfluorophenyl)tetraazaporphyrin µ-oxodimer complex
, which is the first example of a fully fluorinated transition-
of
binuclear
iron(III)
4
475-4478.
Neu, H. M.; Zhdankin, V. V.; Nemykin, V. N. Tetrahedron Lett.
010, 51, 6545-6548.
1
metal tetraazaporphyrin complex possessing an exceptional
resistance to oxidative degradation. Complex 1 is a highly
efficient catalyst for biomimetic oxidations of hydrocarbons
using iodosylbenzene or Oxone as stoichiometric oxidants.
2
Supplementary Material
Supplementary material (experimental procedures and UV-vis
and MCD spectra for complex 1) associated with this article can
be found, in the online version, at doi: .
Acknowledgments
This work was supported by research grants from the National
Science Foundation (CHE-1262479). We are also thankful to the