[Mn(salophen)Cl] supported on modified polystyrene as a selective heterogeneous catalyst for oxidation of sulfides under ultrasonic irradiation

Article abstract of DOI:10.1007/BF03246056

The use of ultrasonic irradiation for the selective synthesis of sulfone in the oxidation of sulfides with NaIO4 catalyzed by Mn(Salophen) supported on chloromethylated polystyrene-bound imidazole, [Mn(Salophene)-PSI], is reported. This heterogeneous cata

Full text of DOI:10.1007/BF03246056

J. Iran. Chem. Soc., Vol. 7, No. 3, September 2010, pp. 673-677.
JOUIRrNaAnLiaOnF THE
Chemical Society
[Mn(salophen)Cl] Supported on Modified Polystyrene as a Selective Heterogeneous
Catalyst for Oxidation of Sulfides under Ultrasonic Irradiation
V. Mirkhani*, S. Tangestaninejad, M. Moghadam, I. Mohammadpoor-Baltork and Z. Saedi
Department of Chemistry, Catalysis Division, University of Isfahan, Isfahan, 81746-73441, Iran
(Received 12 June 2008, Accepted 30 September 2009)
The use of ultrasonic irradiation for the selective synthesis of sulfone in the oxidation of sulfides with NaIO4 catalyzed by
Mn(Salophen) supported on chloromethylated polystyrene-bound imidazole, [Mn(Salophene)-PSI], is reported. This
heterogeneous catalyst efficiently catalyzed selective oxidation of sulfides to sulfones under ultrasonic irradiation and no
sulfoxide was detected in the reaction mixture.
Keywords: Oxidation, Ultrasonic irradiation, Heterogeneous catalyst, Sulfone, Sodium periodate
INTRODUCTION
Ultrasonic waves are known to play a vital role in the
synthesis of organic compounds. The spectacular effects of the
ultrasonic waves are due to the cavitation phenomena which
lead to the production of free radicals and generation of local
hot spots (local conditions of high temperature and pressure)
[24]. Ultrasound can be successfully utilized to enhance the
selectivity as well as conversion of the desired product by
enhancing the rate of the reaction [25].
Oxidation of sulfides under ambient conditions is the most
straightforward method for the synthesis of sulfoxides and
sulfones [26,27]. The synthesis of sulfones has attracted much
attention in fine organic synthesis due to their increasing use
as agrochemicals, pharmaceutical products and lubricants
[26,28].
Transition
metal
complexes
of
porphyrins,
phthallocyanines and Schiff bases have been used for
mimicking the function of P-450 enzymes [1]. The catalytic
activity of these homogeneous catalysts decreases in the
reaction media due to the ligand oxidation or formation of
dimeric oxo- and peroxo-bridged complexes [2,3]. On the
other hand, these catalysts can not be recovered and reused.
One practical way to overcome these problems is the
immobilization of transition metal complexes on solid
supports. Such immobilization makes catalysts recoverable,
reusable and desirable for commercial applications. Schiff
base complexes (salen or salophen) can be immobilized on
supports by non-covalent immobilization in diatomites, clay,
zeolite, activated carbon and siloxane membranes, covalent
grafting onto inorganic supports such as silica or MCM-41,
co-polymerization of a functionalized salen monomer into an
organic polymer and attachment or build-up of a salen
structure to a preformed polymer [4-23].
In the present work, oxidation of sulfides to sulfones with
sodium periodate in the presence of [Mn(salophen)Cl]-PSI, as
a heterogeneous catalyst and under ultrasonic irradiation is
reported (Scheme 1).
EXPERIMENTAL
*Corresponding author. E-mail: mirkhani@sci.ui.ac.ir
All materials were commercial
reagent grade.

Mirkhani et al.
reaction conditions.
N
Since the best solvent in the alkene epoxidation was
CH3CN/H2O mixture, the oxidation of diphenyl sulfide was
studied in different rations of acetonitrile/ water as solvent at
room temperature (Table 1) where upon the 1:2 ratio of
acetonitrile/water mixture was chosen as the desired reaction
medium.
N
N
O
N
O
Mn
Cl
O
S
S
R
R
R
R
NaIO4/CH3CN/H2O
O
Sulfide Oxidation with NaIO4 Ccatalyzed by
[Mn(salophen)Cl]-PSI under Ultrasonic Irradiation
It is well-known that the catalytic ability of manganese
Schiff-bases is improved by the use of a nitrogen base as a
cocatalyst [31,32]. In this study, the polystyrene-bound
imidazole functions not only as a support, but also plays the
axial ligand role in the catalytic system. Reactions took place
under ultrasonic irradiation in CH3CN/H2O containing the
sulfide, the oxidant and the catalyst. The results which are
summarized in Table 2 showed that this catalytic system was
able to catalyze the oxidation of various sulfides such as
aromatic, linear cyclic and heterocyclic sulfides with NaIO4
under ultrasonic irradiation and the corresponding sulfones
were obtained in excellent yields (80-100%). Previously, we
had reported the sulfide oxidation with homogeneous
Mn(salophen)Cl/NaIO4 catalytic system [33]. The obtained
results showed that the products were sulfoxide and sulfone,
while in the present system, sulfones were obtained selectively
under ultrasonic irradiation. The use of different amounts of
oxidant could not change the reaction product and no
sulfoxide was detected in the reaction mixture.
.
)
)
)
)
Scheme 1
Chloromethylated polystyrene (4-5% Cl content and 2% cross-
linked with divinylbenzene) was a product of Merck. The
Schiff base ligand was prepared by the standard procedure of
refluxing ethanolic solutions of the corresponding diamine and
salicylaldehyde derivative in a 1:2 molar ratio [29,30].
[Mn(salophen)Cl-PSI] was synthesized according to our
previously reported method [22]. A UP 400S ultrasonic
processor equipped with a 3 mm wide and 140-mm long
probe, which was immersed directly in the reaction mixture,
was used for sonication.
General Procedure for the Catalytic Oxidation of
Sulfides with Sodium Periodate Catalyzed by
[Mn(salophen)Cl]-PSI under Ultrasonic Irradiation
All of the reactions took place under ultrasonic irradiation
in a 25 ml flask. A solution of NaIO4 (2 mmol) in H2O (10 ml)
was added to
a
mixture of sulfide (1 mmol),
Catalyst Reuse and Stability
[Mn(salophen)Cl]-PSI (0.096 mmol) in CH3CN (5 ml). The
mixture was exposed to ultrasonic irradiation. The progress of
the reaction was monitored by TLC. At the end of the reaction,
the catalyst was filtered and the reaction products were
extracted with Et2O (2 × 10 ml) and purified on a silica-gel
The stability of [Mn(salophen)Cl]-PSI catalyst was studied
in repeated oxidation reactions under ultrasonic irradiation.
The oxidation of diphenyl sulfide was chosen as a model
substrate to study the catalyst reuse and stability. The catalyst
was separated from the reaction mixture after each experiment
by filtration, washed with methanol and dried carefully before
using it in the subsequent run. After the use of the catalyst for
four consecutive times, the sulfone yield was 95%.
1
plate or a silica-gel column. H NMR and IR spectral data
confirmed the identity of the product (Table 1).
RESULTS AND DISCUSSION
The filtrates were used for the determination of manganese
leached by atomic absorption spectroscopy. The results
showed that only a small amount of the catalyst had been
leached in the two first runs (Table 3). Such a finding
The catalytic activity of [Mn(salophen)Cl]-PSI was studied
in the oxidation of diphenyl sulfide in order to optimize
674

[Mn(salophen)Cl] Supported on Modified Polystyrene
Table 1. Effect of Solvent on the Oxidation of Diphenyl Sulfide with NaIO4 Catalyzed by
[Mn(salophen)Cl]-PSI under Ultrasonic Irradiationa
Solvent
Conversion (%)
Sulfone (%)
Time (min)
CH3CN/H2O (1:2)
CH3CN/H2O (1:1)
CH3CN/H2O (2:1)
100
100
100
100
100
100
7
15
25
aDiphenyl sulfide (1 mmol), NaIO4 (2 mmol), catalyst (0.096 mmol), CH3CN (5 ml), H2O
(10 ml).
Table 2. Oxidation of Sulfides with NaIO4 Catalyzed by [Mn(salophen)Cl]-PSI under Ultrasonic Irradiationa
Entry
1
Sulfide
Conversion (%)
100
Sulfone (%)
100
Time (min)
7
S
S
CH3
2
100
100
25
S
3
4
100
80
100
80
15
25
S
H
N
5
6
7
100
100
100
100
100
100
10
85
75
S
N
H
N
S
S
C
Br
H2
N
O
C
H2
N
aSulfide (1 mmol), NaIO4 (2 mmol), catalyst (0.096 mmol), CH3CN (5 ml), H2O (10 ml).
confirmed the strong covalent bonding of the polymer and the
metallosalophen, in which the [Mn(salophen)Cl] catalyst was
not leached from the polymer during the oxidation reaction.
and elegant techniques for the oxo functionalization of organic
substrates. Mn(salophen)Cl supported on polystyrene bound
imidazole, ([Mn(salophen)Cl]-PSI is an efficient catalyst for
oxidation of sulfides with NaIO4 under ultrasonic irradiation.
The results showed that the ultrasonic irradiation enhanced the
product yield and selectivity. Moreover, the catalyst could be
reused several times without significant loss of its catalytic
activity.
CONCLUSIONS
The selective oxygenation of organic compounds catalyzed
by transition metal copmounds is one of the most productive
675

Mirkhani et al.
Table 3. Catalyst Reuse and Stability in the Oxidation of Diphenyl Sulfide under
Ultrasonic Irradiation
Entry
Conversion (%)
Time (min)
Mn leached (%)a
1
2
3
4
100
98
95
7
7
7
7
0.5
0.2
0
95
0
aDetermined by atomic absorption spectroscopy.
ACKNOWLEDGEMENTS
[11] M.R. Maurya, S.J. Titinchi, S. Chand, J. Mol. Catal. A:
Chem. 177 (2002) 1.
The financial support of this work by the Research Council
of the University of Isfahan is gratefully acknowledged
(Project No. 860308).
[12] A. Heckel, D. Seebach, Helvetica Chem. Acta 85
(2002) 913.
[13] D.A. Annis, E.N. Jacobsen, J. Am. Chem. Soc. 121
(1999) 4147.
REFERENCES
[14] H. Zhang, S. Xiang, C. Li, Chem. Commun. (2005)
1209.
[1]
a) T. Katsuki, J. Mol. Catal. A: Chem. 113 (1996) 87;
b) T. Katsuki, Coord. Chem. Rev. 140 (1995) 189; c)
W. Nam, S.E. Park, I.K. Lim, M.H. Lim, J. Hong, J.
Kim, J. Am. Chem. Soc. 125 (2003) 14674.
[15] S. Xiang, Y. Zhang, Q. Xin, C. Li, Chem. Commun.
(2002) 2696.
[16] Y.R. de Miguel, J. Chem. Soc., Perkin Trans. 1 (2000)
4213.
[2]
[3]
[4]
[5]
[6]
[7]
[8]
[9]
K. Srinivasan, P. Michaud, J.K. Kochi, J. Am. Chem.
Soc. 108 (1986) 2309.
[17] G.-J. Kim, S.-H. Kim, Catal. Lett. 57 (1999) 139.
[18] L. Canali, D.C. Sherrington, H. Deleuze, React. Funct.
Polym. 40 (1999) 155.
[19] S.T. Regar, K.D. Janda, J. Am. Chem. Soc. 122 (2000)
6929.
[20] B. Bahramian, V. Mirkhani, M. Moghadam, S.
Tangestaninejad, J. Mol. Catal. A: Chem. 244 (2006)
139.
[21] B. Bahramian, V. Mirkhani, M. Moghadam, S.
Tangestaninejad, Catal. Commun. 7 (2006) 289.
[22] V. Mirkhani, M. Moghadam, S. Tangestaninejad, B.
Bahramian, Appl. Catal. A: Gen. 311 (2006) 43.
[23] V. Mirkhani, M. Moghadam, S. Tangestaninejad, B.
Bahramian, Polyhedron 25 (2006) 2904.
[24] M.A. Kelkar, R.P. Gogate, A.B. Pandit, Ultrason.
Sonochem. 13 (2006) 523.
J.P. Collman, V.J. Lee, C.J. Kellen-Yuen, X. Zhang,
J.A. Brauman, J. Am. Chem. Soc. 117 (1995) 692.
A.R. Silva, C. Freire, B. de Castro, M.M.A. Freitas, J.L.
Figueiredo, Micropor. Mesopor. Mater. 46 (2001) 211.
A.R. Silva, C. Freire, B. de Castro, M.M.A. Freitas, J.L.
Figueiredo, Langmuir 18 (2002) 8017.
A.R. Silva, J. Vital, J.L. Figueiredo, C. Freire, B. de
Castro, New J. Chem. 27 (2003) 1511.
I. Kuzniarska-Biernacka, A.R. Silva, A.P. Carvalho, J.
Pires, C. Freire, J. Mol. Catal. A: Chem. 278 (2007) 82.
S.P. Varkey, C. Ratnasamy, P. Ratnasamy, J. Mol.
Catal. A: Chem. 135 (1998) 295.
M. Silva, C. Freire, B. de Castro, J.L. Figueiredo, J.
Mol. Catal. A: Chem. 258 (2006) 327.
[10] J.M. Fraile, J.I. Garcia, J. Massam, J.A. Mayoral, J.
Mol. Catal. A: Chem. 136 (1998) 47.
[25] N.N. Mahamuni, R.P. Gogate, A.B. Pandit, A.B.
Ultrason. Sonochem. 14 (2007) 135.
676

[Mn(salophen)Cl] Supported on Modified Polystyrene
[26] K. Bahrami, Tetrahedron Lett. 47 (2006) 2009.
[27] D.A. Alonso, C. Najera, M. Varea, Tetrahedron Lett. 43
(2002) 3459.
S. Satish, J. Mol. Catal. 75 (1992) 109.
[31] J.P. Collman, L. Zeng, I.J. Brauman, Inorg. Chem. 43
(2004) 2672.
[28] A. Arcoria, F.P. Ballistreri, J. Mol. Catal. 18 (1983) 177.
[29] G.J. Kim, D.W. Park, Catal. Today 63 (2000) 537.
[30] a) D. Chan, A.E. Martell, Inorg. Chem. 26 (1987) 1026;
b) B.M. Trivedi, P.K. Bhattacharya, P.A. Ganeshpure,
[32] Z. Groos, S. Ini, J. Org. Chem. 62 (1997) 5514.
[33] V. Mirkhani, S. Tangestaninejad, M. Moghadam, I.
Mohammadpoor-Baltork, H. Kargar, J. Mol. Catal. A:
Chem. 242 (2005) 251.
677