Immobilized molybdenum-thiosemicarbazide Schiff base complex on the surface of magnetite nanoparticles as a new nanocatalyst for the epoxidation of olefins

Article abstract of DOI:10.1016/j.jmmm.2013.11.013

In this work, a new magnetically recoverable nanocatalyst was developed by immobilization of thiosemicarbazide ligand on the surface of silica coated magnetite nanoparticles (SCMNPs) through Schiff base condensation and followed complexation with MoO₂(acac)₂. Characterization of the prepared nanocatalyst was performed with different physicochemical methods such as Fourier transform infrared (FT-IR) and atomic absorption spectroscopies, X-ray diffraction (XRD), vibrating sample magnetometry (VSM), thermogravimetric analysis (TGA), field-emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM). The prepared catalyst catalyzed the epoxidation of olefins and allyl alcohols with tert-butyl hydroperoxide (TBHP) and cumene hydroperoxide (CHP) quantitatively with excellent selectivity toward the corresponding epoxides under mild reaction conditions.

Full text of DOI:10.1016/j.jmmm.2013.11.013

Journal of Magnetism and Magnetic Materials 354 (2014) 317–323
Contents lists available at ScienceDirect
Journal of Magnetism and Magnetic Materials
journal homepage: www.elsevier.com/locate/jmmm
Immobilized molybdenum–thiosemicarbazide Schiff base complex
on the surface of magnetite nanoparticles as a new nanocatalyst
for the epoxidation of olefins
b
b
M. Mohammadikish a, , M. Masteri-Farahani , S. Mahdavi
n
a Department of Chemistry, Faculty of Sciences, Kermanshah Branch, Islamic Azad University, Kermanshah, Islamic Republic of Iran
b Faculty of Chemistry, Kharazmi University, Tehran, Islamic Republic of Iran
a r t i c l e i n f o
a b s t r a c t
Article history:
In this work, a new magnetically recoverable nanocatalyst was developed by immobilization of thiosemi-
carbazide ligand on the surface of silica coated magnetite nanoparticles (SCMNPs) through Schiff base
condensation and followed complexation with MoO2(acac)2. Characterization of the prepared nanocatalyst
was performed with different physicochemical methods such as Fourier transform infrared (FT-IR) and
atomic absorption spectroscopies, X-ray diffraction (XRD), vibrating sample magnetometry (VSM), thermo-
gravimetric analysis (TGA), field-emission scanning electron microscopy (FE-SEM), and transmission electron
microscopy (TEM). The prepared catalyst catalyzed the epoxidation of olefins and allyl alcohols with tert-
butyl hydroperoxide (TBHP) and cumene hydroperoxide (CHP) quantitatively with excellent selectivity
toward the corresponding epoxides under mild reaction conditions.
Received 20 September 2013
Received in revised form
31 October 2013
Available online 21 November 2013
Keywords:
Magnetite
Thiosemicarbazide
Molybdenum
Immobilization
Epoxidation
& 2013 Elsevier B.V. All rights reserved.
1. Introduction
Thus, design of new hybrid nanomaterials which have appropriate
interactions between the support and active components is of
Design and construction of hybrid nanomaterials with tunable
physical properties have attracted extensive interest in material
chemistry [1–6]. This field of research bridges different types of
chemistry (organic, inorganic, and coordination) to materials
science and also opens many possibilities for physical properties.
These materials embody the desirable features of both inorganic
and organic materials. The ability to integrate the chemical
functionality and diversity of soft matter onto a mechanically
robust inorganic scaffold has long been of interest in numerous
applications especially catalysis [7–9].
Soluble transition metal complexes (i.e. homogeneous cata-
lysts) catalyze numerous interesting chemical reactions including
C–C bond formation, oxidation reactions, etc. [10–12]. However,
recovering these catalysts from solution poses a considerable
challenge. Catalyst separation and recycling are essential steps in
catalytic processes and affect the overall process economy. Attach-
ing these homogeneous catalysts to solid supports that are easy to
recover and retain the activity of the homogeneous catalysts
would have numerous benefits in terms of process design and
environmental factors. Facile recovery and reuse while maintain-
ing high catalytic activity of the supported homogeneous catalysts
offer a particularly efficient catalyst for a wide variety of reactions.
great importance for catalytic purposes [7–9,13].
On the other hand, it was known that molybdenum (VI) based
catalysts, especially the cis-dioxomolybdenum species, have high
catalytic activities for the selective epoxidation of olefins. Although
great efforts have been made to immobilize homogeneous molyb-
denum catalysts on the surface of various supports such as functio-
nalized polymers [14–17], zeolites [18–21], mesoporous molecular
sieves [22–30], and multi-walled carbon nanotubes (MWCNTs)
surfaces [31–33] there are a little reports in the literature regarding
covalent attachment of molybdenum complexes on the silica coated
magnetite nanoparticles [34–36].
Surface modified magnetite nanoparticles can be used as
support to prepare heterogenized catalysts that are more acces-
sible to the reagents as compared to classic heterogeneous systems
[34–44]. Magnetite nanoparticles which can be easily produced by
the co-precipitation of Fe(II) and Fe(III) salts in basic conditions
have superparamagnetic properties that give it exceptional beha-
viors suitable both for catalytic reactions in solution and for
magnetic recovery. These nanoparticles are easily dispersible and
have no tendency to aggregate in solution, but are readily
magnetized by an external magnetic field which favors their easy
separation from the reaction mixture. In addition, internal diffu-
sion limitations of porous supports can be avoided, because all of
the available surface area of the nonporous magnetite nanoparti-
cles is external. The surface of magnetite nanoparticles can be
functionalized to protect the magnetite core from chemical
n
Corresponding author. Tel./fax: + 98 831 725 2218.
E-mail address: mohammadikish@yahoo.com (M. Mohammadikish).
0304-8853/$ - see front matter & 2013 Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.jmmm.2013.11.013

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M. Mohammadikish et al. / Journal of Magnetism and Magnetic Materials 354 (2014) 317–323
reactions and also provide functional groups for immobilization of
desired catalytic species.
atmosphere. The mixture was refluxed for 12 h and the resultant
solid was magnetically separated, washed with methanol to
remove the unreacted residue of silylating reagent and then
vacuum dried at 80 1C.
Our current interest in the immobilization of molybdenum
complexes on different supports [25–29,33–35] led us to investi-
gate the preparation and characterization of a new covalently
attached molybdenum hybrid nanomaterial on the surface of silica
coated magnetite nanoparticles. The preparation of this hybrid
nanomaterial is based on successive Schiff base condensation of
amine modified silica coated magnetite nanoparticles with ter-
ephthaldehyde and thiosemicarbazide to give a supporting ligand
to which molybdenum was coordinated in final step. The main
advantage of the system is relatively strong interaction of molyb-
denum complex attached on the surface of magnetite nanoparti-
cles which prevent from leaching to reaction mixture during
catalytic reactions. The presence of thiosemicarbazide as good
donor ligand enhances the catalytic activity of the prepared
nanomaterial in the epoxidation of olefins. On the other hand,
due to the presence of magnetite core, the prepared hybrid
nanomaterial has superparamagnetic properties which make its
easy recovery and reuse in catalytic reactions.
2.1.2. Immobilization of thiosemicarbazide on the surface of silica
coated magnetite nanoparticles
The prepared AmpSCMNPs (2 g) suspended in 100 ml of
ethanol with sonication were mixed with excess of terephthalde-
hyde (4 mmol) and the resultant mixture was refluxed for 24 h.
The resultant solid (named as tereph-SCMNPs) was separated mag-
netically and washed with ethanol several times to remove the
unreacted residue of the terephthaldehyde. Afterwards, the
obtained tereph-SCMNPs (2 g) were suspended in ethanol
(100 ml) and thiosemicarbazide (4 mmol) was added under dry
nitrogen atmosphere. The mixture was refluxed for 24 h and the
resultant solid, named as thio-SCMNPs, was magnetically separated,
washed with methanol to remove the unreacted reagents and then
vacuum dried at 80 1C.
2.1.3. Immobilization of molybdenum complex on the surface of
magnetite nanoparticles
2. Experimental
Excess of MoO2(acac)2 (4 mmol) was dissolved in ethanol
(50 ml). The prepared thio-SCMNPs (2 g, dried in vacuum oven
at 80 1C) was then added to this solution with sonication and the
mixture was refluxed for 12 h. After separation with an external
magnet, the product was washed with methanol to remove
unreacted MoO2(acac)2. The resultant MoO2–thio-SCMNPs material
was then dried under vacuum at 80 1C.
2.1. Materials and instrumentation
All chemicals were purchased from Merck chemical company
and used without further purification. MoO2(acac)2 was prepared
according to literature [45] and its structure was confirmed by
spectroscopic methods.
Fourier transform infrared (FT-IR) spectra were recorded on
Rayleigh WQF-510 spectrophotometer using pellets of the materials
diluted with KBr. Chemical analyses of the samples were carried out
with VARIAN VISTA-MPX ICP-AES atomic absorption spectrometer.
The crystalline phase of the prepared nanomaterial was identified by
means of X-ray diffraction measurements using Cu Kα radiation
(λ¼1.54 Å) on a SIEFERT XRD 3003 PTS diffractometer in the 2θ range
of 10–801. Magnetic susceptibility measurements were carried out
using a vibrating sample magnetometer (VSM) (BHV-55, Riken, Japan)
in the magnetic field range of ꢀ8000 Oe to 8000 Oe at room
temperature. Thermogravimetric measurements were made on a
Perkin Elmer Diamond Thermogravimeter. The temperature was
increased to 700 1C using a rate of 10 1C/min in static air. The
transmission electron micrographs (TEM) of the nanoparticles were
recorded using a Philips EM 208 S instrument with an accelerating
voltage of 100 kV. Samples were prepared for TEM by placing droplets
of a suspension of the sample in acetone on a polymer microgrid
supported on a Cu grid. Scanning electron micrographs (SEM) of the
samples were taken with ZEISS-DSM 960A microscope with attached
camera.
2.2. Catalytic epoxidation of olefins in the presence of MoO2–thio-
SCMNPs
Epoxidation of olefins was carried out in a 25 ml round
bottomed flask equipped with a condenser and a magnetic stirrer.
Tert-butylhydroperoxide (80% in di-tertiary butyl peroxide) or
cumene hydroperoxide (80% in cumene) were used as oxidants.
In a typical procedure, to a mixture of catalyst (100 mg) and olefin
(8 mmol) in chloroform (10 ml) oxidant was added (14.4 mmol)
under nitrogen atmosphere and the mixture was refluxed for
appropriate time. Samples were withdrawn periodically and after
dilution with chloroform and cooling were analyzed using a gas
chromatograph (HP, Agilent 6890N) equipped with a capillary
column (HP-5) and a FID detector. Products were quantified using
isooctane (1 g, 8.75 mmol) as internal standard. GC–MS of pro-
ducts were recorded using a Shimadzu-14A fitted with a capillary
column (CBP5-M25). In order to perform the recovery test, the
epoxidation of cyclooctene was allowed to proceed 2 h. The
catalyst was then recovered magnetically at the reaction tempera-
ture and the solution was decanted into a clean 25 ml flask and
refluxed for 24 h. The conversions and selectivities were deter-
mined after 2 and 24 h.
2.1.1. Preparation of silica coated magnetite nanoparticles (SCMNPs)
and aminoropropyl modified SCMNPs (AmpSCMNPs)
The molybdenum content of recycled catalyst was measured
with above mentioned atomic absorption spectrometer after
digestion of the filtered catalyst in hydrochloric acid solution.
Magnetite nanoparticles (MNPs) were prepared according to
reported method [42]. For preparation of SCMNPs, the magnetite
nanoparticles (1 g) were dispersed in deionized water in a 250 ml
round-bottom flask with sonication and then an aqueous solution
of TEOS (10% (v/v), 80 ml) was added, followed by glycerol (50 ml).
The pH of the suspension was adjusted to 4.5 using glacial acetic
acid, and the mixture was then stirred and heated at 90 1C for 2 h
under a nitrogen atmosphere. After cooling to room temperature,
the silica coated magnetite nanoparticles was separated from the
reaction mixture using a permanent magnet and washed several
times with distilled water and methanol. The obtained SCMNPs
(2 g) were suspended in ethanol (100 ml) and then aminoropro-
pyltrimethoxysilane (2 ml) was added under dry nitrogen
3. Results and discussion
3.1. Preparation of MoO2–thio-SCMNPs nanomaterial
The sequence of reactions in the functionalization of magnetite
nanoparticles (MNPs) with molybdenum thiosemicarbazide derived
Schiff base complex has been shown in Fig. 1. First, the external
surface of MNPs was coated with a silica shell to obtain silica
coated magnetite nanoparticles (SCMNPs). Then, treatment of

M. Mohammadikish et al. / Journal of Magnetism and Magnetic Materials 354 (2014) 317–323
319
Fig. 1. The sequence of events in the preparation of MoO2–thio-SCMNPs.
120
100
80
60
40
20
0
silanol (Si-OH) groups of SCMNPs with aminoropropyltrimethox-
thio-SCMNPs
ysilane afforded aminoropropylated silica coated magnetite nano-
particles (AmpSCMNPs). During this reaction, the silylating reagent
reacts with the Si-OH groups on the surface of SCMNPs to form a
stable Si-O-Si bond through which the aminopropyl chain was
attached to the surface of SCMNPs. The next step involves Schiff
base condensation reaction of amino groups in AmpSCMNPs with
carbonyl groups of terephthaldehyde to yield the tereph-SCMNPs
[46]. Binding of thiosemicarbazide molecules to modified magnetite
nanoparticles is achieved through the next Schiff base condensation
reaction between remained carbonyl group in the tereph-SCMNPs
and the amine groups of the thiosemicarbazide molecules. In the
final step, complexation of the thio-SCMNPs was performed with
excess of MoO2(acac)2 to afford MoO2–thio-SCMNPs. Soxhlet extrac-
tion of the product was carried out subsequently in order to remove
the unreacted MoO2(acac)2 from the resultant nanomaterial.
MoO -thio-SCMNPs
2
1363
806
904
1522
1601
937
584
461
1086
3900
3400
2900
2400
1900
1400
900
400
Wave number (cm-1)
Fig. 2. FT-IR spectra of (a) thio-SCMNPs and (b) MoO2–thio-SCMNPs nanomaterials.
3.2. Characterization of the prepared MoO2–thio-SCMNPs
nanomaterial
The strong and broad absorption band at about 1000–1100 cm ꢀ1
revealed the presence of Si-O-Si and Si–O–H stretching vibrations
and confirmed the presence of silica shell on the surface of
magnetite nanoparticles. The presence of anchored propyl chain
was confirmed by C-H stretching vibrations appearing at about
2923 cmꢀ1). In the FT-IR spectrum of thio-SCMNPs, the bands
observed at 3256 and 3423 cmꢀ1 were assigned to N–H vibrations
In order to verify the functionalization of the magnetite surface,
the FT-IR spectra of the prepared thio-SCMNPs and MoO2–thio-
SCMNPs nanomaterials were obtained and have been shown in
Fig. 2. The observation of two broad bands at around 450–
590 cmꢀ1 indicates the characteristic absorption bands of the Fe-O
bonds in the magnetite core of the prepared nanomaterials [47].

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M. Mohammadikish et al. / Journal of Magnetism and Magnetic Materials 354 (2014) 317–323
which indicate that the ligand remained in the thione form. The
possibility of thione–thiol tautomerism in the ligand was ruled out
as no band around 2700–2500 cmꢀ1, characteristic of the thiol
group, was observed in the FT-IR spectrum. The bands at 1522 and
1601 cmꢀ1 can be assigned to C¼N stretching vibrations, and
some weak bands at 1400–1500 cmꢀ1 assigned to stretching
vibrations of aromatic rings of thio-SCMNPs were observed that
were not present in parent SCMNPs. The appearance of two
adjacent bands at 904 and 937 cmꢀ1 in the FT-IR spectrum of
complexed material is characteristic of the presence of cis-MoO2
group [48] and formation of MoO2–thio-SCMNPs nanomaterial.
Molybdenum content of the prepared nanomaterial was found
to be 0.064 mmol gꢀ1 on the basis of ICP-AES chemical analysis
and further confirmed the presence of molybdenum complex in
the final product.
250
311
200
150
440
100
Fig. 3 depicts the XRD pattern of the MoO2–thio-SCMNPs
nanomaterial. The diffraction peaks can be assigned to the planes
of inverse cubic spinel structured Fe3O4 (JCPDS no. 19-0629).
The broad peaks indicate the nanocrystalline nature of the pre-
pared MoO2–thio-SCMNPs nanomaterial.
To study the magnetic properties of magnetite nanoparticles
before and after modifications the hysteresis loops of magnetite
and functionalized magnetite nanoparticles were investigated at
room temperature using vibrating sample magnetometry (VSM).
220
511
411
50
0
422
533
10
20
30
40
50
60
70
80
2θ / °
Fig. 3. XRD pattern of the prepared MoO2–thio-SCMNPs.
60
40
MNPs
AmpSCMNPs
Mo-thio-SCMNPs
20
0
-8000
-6000
-4000
-2000
0
2000
4000
6000
8000
Applied field (Oe)
-20
-40
-60
Fig. 4. Magnetization curves of (a) MNPs, (b) AmpSCMNPs, and (c) MoO2–thio-SCMNPs.
Fig. 5. TGA curves of the prepared MoO2–thio-SCMNPs.

M. Mohammadikish et al. / Journal of Magnetism and Magnetic Materials 354 (2014) 317–323
321
Magnetization curves of prepared materials are shown in Fig. 4.
The magnetization curve of MNPs exhibited no remanence effect
(superparamagnetic property) with saturation magnetization of
about 60 emu/g. Also, the aminoprpylated silica coated magnetite
nanoparticles (AmpSCMNPs) showed superparamagnetic behavior
with decreased saturation magnetization of about 42 emu/g. The
MoO2–thio-SCMNPs nanomaterial exhibited superparamagnetic
properties with saturation magnetization of about 20 emu/g. The
superparamagnetic properties of the prepared MoO2–thio-
SCMNPs nanomaterial are critical for its application, which pre-
vent aggregation and enables it to redisperse rapidly when the
magnetic field is removed.
The thermal behavior of the MoO2–thio-SCMNPs was investi-
gated by thermogravimetric analysis. Fig. 5 shows the TGA, DTG
and DTA curves for the prepared MoO2–thio-SCMNPs. The TGA
and DTG curves indicate only one stage of mass reduction as a
function of temperature. Due to the hydrophobic nature of the
prepared nanomaterial, the amount of adsorbed water below
200 1C was only 2 wt%. The main weight loss at about 300–
450 1C was assigned to the combustion of organic compounds
which is in good agreement with exothermic DTA peak in this
region.
alcohols in the presence of TBHP in comparison with CHP. This can
be explained with more electrophilic character of the peroxidic
oxygen in TBHP. On the basis of previously reports it has been
indicated that the epoxidation of olefins in the presence of cis-
dioxomolybdenum(VI) complexes involves the coordination of
TBHP to the Lewis acidic molybdenum center in the first step
[49]. The peroxidic oxygen would have electrophilic character and
the catalytic epoxidation goes through electrophilic oxygen atom
transfer from molybdenum alkyl peroxide to the olefin.
100
80
60
40
1-octene-3-ol
Fig. 6a shows the FE-SEM image of the prepared nanomaterial.
The FE-SEM image indicates that the obtained product is com-
posed of spherical nanoparticles. Aggregation gives rise to increase
in the size of observed nanoparticles as seen in the FE-SEM image.
Transmission electron micrograph of the prepared nanomater-
ial has been shown in Fig. 6b. As can be seen, most of the
nanoparticles are aggregated. The particle size is about 15 nm in
the edges of the aggregated nanoparticles.
20
3-methyl-2-butene-1-ol
trans-2-hexene-1-ol
0
0
4
8
12
16
20
24
Time (h)
100
80
60
40
20
0
3.3. Catalytic epoxidation of olefins and allyl alcohols in the presence
of MoO2–thio-SCMNPs
The catalytic activity of the MoO2–thio-SCMNPs nanomaterial
was evaluated in the epoxidation of some olefins and allyl alcohols
with TBHP and CHP as oxidants, and the results are presented in
Figs. 7–9. It was found that the MoO2–thio-SCMNPs nanomaterial
can act as an active catalyst and selectively yielded the corre-
sponding epoxides. It is worth noting that the MoO2–thio-SCMNPs
has comparable catalytic activity to our previous catalysts hetero-
genized on the surface of large surface area MCM-41 [25–29].
This can be interpreted by considering the fact that compared to
the those catalysts with higher surface area but narrow pore size,
the MoO2–thio-SCMNPs has no diffusion limitations, as all of the
molybdenum active sites are located on the external surface area
of SCMNPs. On the other hand, it seems that the presence of S-
donor Schiff base ligand in the final structure of catalyst increases
the catalytic activity of the present catalyst in comparison with
similar catalysts immobilized on the surface of SCMNPs.
1-octene-3-ol
3-methyl-2-butene-1-ol
trans-2-hexene-1-ol
0
4
8
12
16
20
24
Time (h)
Fig. 7. Results of epoxidation of allyl alcohols with (a) TBHP, and (b) CHP in the
presence of MoO2–thio-SCMNPs. Reaction conditions: catalyst (100 mg), olefin
(8 mmol), TBHP (1.6 ml, 14.4 mmol), refluxing chloroform (10 ml).
A noticeable point when comparing the results of the epoxida-
tion reactions is the more reactivities of the olefins and allyl
Fig. 6. (a) FE-SEM and (b) TEM images of prepared MoO2–thio-SCMNPs.

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M. Mohammadikish et al. / Journal of Magnetism and Magnetic Materials 354 (2014) 317–323
Table 1
100
80
60
40
20
0
Results of the epoxidation of cyclooctene with TBHP.
Entry
Time (h)
Conversion (%)
Selectivitya (%)
1b
2c
3d
12
12
2
16
14
31
36
36
41
499
99
24
Reaction conditions: catalyst (100 mg), olefin (8 mmol), TBHP (14.4 mmol), reflux-
a
ing chloroform (10 ml).
Selectivity toward epoxycyclooctane.
b
Reaction was carried out in the presence of SCMNPs.
Reaction was carried out in the absence of catalyst.
Result after filtering the catalyst.
c
cyclooctene
cyclohexene
d
Recovery test was performed on the prepared nanocatalyst to
evaluate whether the catalysis was occurring via surface bound
nanocatalyst. In a separate test epoxidation of cyclooctene was
allowed to proceed 2 h (ca. 31% cyclooctene conversion, Table 1).
The MoO2–thio-SCMNPs was then recovered magnetically at the
reaction temperature to avoid re-adsorption of the solubilized
species and the solution was decanted into a clean 25 ml flask. The
solution was refluxed for 24 h to elucidate whether conversion
resulted from homogeneous catalyst leached from the support or
surface bound molybdenum catalyst. The conversions and selec-
tivities were determined after 2 and 24 h and it was found that
the conversion only slightly increased to 36% and then remains
constant (Table 1).
After using MoO2–thio-SCMNPs as catalyst, no molybdenum
was detected in the solution by ICP-AAS. On the other hand, the
recovered nanocatalyst was reused for the epoxidation of
3-methyl-2-butene-1-ol and the reaction results are presented in
Fig. 9. The results show that the activity and selectivity do not
decrease significantly for at least two uses of the catalyst. So, from
these results it can be concluded that molybdenum species is
strongly bonded to the surface of SCMNPs and the prepared
nanocatalyst is stable in the reaction conditions and that the
epoxidation reaction is truly heterogeneous.
0
4
8
12
16
20
24
Time (h)
100
80
60
40
20
0
cyclooctene
cyclohexene
0
4
8
12
16
20
24
Time (h)
Fig. 8. Results of epoxidation of olefins with (a) TBHP, and (b) CHP in the presence
of MoO2–thio-SCMNPs. Reaction conditions: catalyst (100 mg), olefin (8 mmol),
CHP (14.4 mmol), refluxing chloroform (10 ml).
100
80
4. Conclusion
In conclusion, the use of modified magnetite nanoparticles to
design an efficient magnetically recoverable nanocatalyst for
epoxidation of olefins has been demonstrated. First, the external
surface of silica coated magnetite nanoparticles were modified
with aminopropyltriethoxy silane and terephthaldehyde. After-
wards, Schiff base condensation reaction resulted in immobiliza-
tion of thiosemicarbazide molecules on the surface of modified
magnetite nanoparticles. Subsequent complexation of the sup-
ported ligands with molybdenum precursor afforded a magneti-
cally recoverable truly heterogenized molybdenum nanocatalyst
which is active and selective in catalytic epoxidation of olefins and
allylic alcohols. No contribution from homogeneous catalysis by
molybdenum species leached into reaction mixture during the
course of the reaction was detected.
60
1st use
40
2nd use
20
0
3rd use
0
4
8
12
16
20
24
Time (h)
Fig. 9. Results of epoxidation of 3-methyl-2-butene-1-ol with TBHP in the presence
of recycled MoO2–thio-SCMNPs.
References
[1] G. Kickelbick, Hybrid Materials: Synthesis, Characterization, and Applications,
in: G. Kickelbick (Ed.), Wiley-VCH, Weinheim, 2007.
[2] F. Hoffmann, M. Cornelius, J. Morell, M. Froba, Angew. Chem. Int. Ed. 45 (2006)
3216–3251.
[3] C. Sanchez, B. Julian, P. Belleville, M. Popall, J. Mater. Chem. 15 (2005) 3559–3592.
[4] D. Eder, Chem. Rev. 110 (2010) 1348–1385.
[5] G. Cerveau, R.J.P. Corriu, E. Framery, Chem. Mater. 13 (2001) 3373–3388.
[6] M.F. Ashby, Y.J.M. Brechet, Acta Mater. 51 (2003) 5801–5821.
[7] M.H. Valkenberg, W.F. Holderich, Catal. Rev. 44 (2002) 321–374.
[8] J.J.E. Moreau, M.W.C. Man, Coord. Chem. Rev.178–180 (1998) 1073–1084.
Furthermore, allyl alcohols are more reactive than simple
olefins. This is probably due to the participation of hydroxyl group
in approaching the double bond to the electrophilic oxygen center.
The results of epoxidation of cyclooctene in the absence of the
catalyst are included in Table 1 in order to clear up the catalytic
effect of the prepared MoO2–thio-SCMNPs. As can be seen, no
significant reaction occurred in the absence of the catalyst.

M. Mohammadikish et al. / Journal of Magnetism and Magnetic Materials 354 (2014) 317–323
323
[9] A.P. Wight, M.E. Davis, Chem. Rev. 102 (2002) 3589–3614.
[10] R.A. Sheldon, J.K. Kochi, Metal-Catalyzed Oxidation of Organic Compounds,
Academic Press, New York, 1981.
[11] G.W. Parshall, S.D. Itel, Homogeneous Catalysis: The Application and Chem-
istry of Catalysis by Transition Metal Complexes, 2nd ed., Wiley-Interscience,
New York, 1992.
[12] K.A. Jorgensen, Chem. Rev. 89 (1989) 431–458.
[13] M. Masteri-Farahani, J. Movassagh, F. Taghavi, P. Eghbali, F. Salimi, Chem. Eng.
J. 184 (2012) 342–346.
[14] St.V. Kotov, St. Boneva, T.S. Kolev, J. Mol. Catal. A: Chem. 154 (2000) 121–129.
[15] M.M. Miller, D.C. Sherrington, J. Catal. 152 (1995) 368–376.
[16] S. Tangestaninejad, M.H. Habibi, V. Mirkhani, M. Moghadam, G. Grivani, Inorg.
Chem. Commun. 9 (2006) 575–578.
[17] R. Mbeleck, K. Ambroziak, B. Saha, D.C. Sherrington, React. Funct. Polym. 67
(2007) 1448–1457.
[18] A. Fuerte, M. Iglesias, F. Sanchez, A. Corma, J. Mol. Catal. A: Chem. 211 (2004)
227–235.
[19] A. Antinollo, P. Canizares, F. Carrillo-Hermosilla, Appl. Catal. A 193 (2000)
139–146.
[20] R. Kumar Rana, B. Viswanathan, Catal. Lett. 52 (1998) 25–29.
[21] M. Masteri-Farahani, F. Farzaneh, M. Ghandi, J. Mol. Catal. A: Chem. 192 (2003)
103–111.
[22] M. Jia, W.R. Thiel, Chem. Commun. (2002) 2392–2393.
[23] M. Jia, A. Siefert, W.R. Thiel, Chem. Mater. 15 (2003) 2174–2185.
[24] C.D. Nones, M. Pillinger, A. Valente, I.S. Goncalves, Chem. Commun. 6 (2003)
1228–1233.
[25] M. Masteri-Farahani, F. Farzaneh, M. Ghandi, J. Mol. Catal. A: Chem. 248 (2006)
53–60.
[26] M. Masteri-Farahani, F. Farzaneh, M. Ghandi, Catal. Commun. 8 (2007) 6–10.
[27] M. Masteri-Farahani, M. Sadeghi, Y. Abdollahi, M.M. Kashani Motlagh,
F. Salimi, J. Nanostruct. 2 (2012) 111–118.
[28] M. Masteri-Farahani, F. Farzaneh, M. Ghandi, J. Mol. Catal. A: Chem. 243 (2006)
170–175.
[29] M. Masteri-Farahani, J. Mol. Catal. A: Chem. 316 (2010) 45–51.
[30] S.M. Bruno, J.A. Fernandes, L.S. Martins, I.S. Goncalves, M. Pillinger, P. Ribeiro-
Claro, J. Rocha, A.A. Valente, Catal. Today 114 (2006) 263–271.
[31] M. Moghadam, S. Tangestaninejad, V. Mirkhani, I. Mohammadpoor-Baltork,
A. Mirjafari, N.S. Mirbagheri, J. Mol. Catal. A: Chem. 329 (2010) 44–49.
[32] M. Salavati-Niasari, M. Bazarganipour, Transit. Met. Chem. 33 (2008) 751–757.
[33] M. Masteri-Farahani, S. Abednatanzi, Inorg. Chem. Commun. 37 (2013) 39–42.
[34] M. Masteri-Farahani, N. Tayyebi, J. Mol. Catal. A: Chem. 348 (2011) 83–87.
[35] M. Masteri-Farahani, Z. Kashef, J. Magn. Magn. Mater. 324 (2012) 1431–1434.
[36] S. Shylesh, J. Schweizer, S. Demeshko, V. Schunmann, S. Ernst, W.R. Thiel, Adv.
Synth. Catal. 351 (2009) 1789–1795.
[37] L.M. Rossi, I.M. Nangoi, N.J.S. Costa, Inorg. Chem. 48 (2009) 4640–4642.
[38] A. Hu, G.T. Yee, W. Lin, J. Am. Chem. Soc. 127 (2005) 12486–12487.
[39] B. Panella, A. Vargas, A. Baiker, J. Catal. 261 (2009) 88–93.
[40] C.S. Gill, B.A. Price, C.W. Jones, J. Catal. 251 (2007) 145–152.
[41] B. Baruwati, D. Guin, S.V. Manorama, Org. Lett. 9 (2007) 5377–5380.
[42] Z. Wang, P. Xiao, B. Shen, N. He, Colloids Surf. A: Physicochem. Eng. Asp. 276
(2006) 116–121.
[43] M.J. Jacinto, R. Landers, L.M. Rossi, Catal. Commun. 10 (2009) 1971–1979.
[44] V. Polshettiwar, R. Luque, A. Fihri, H. Zhu, M. Bouhrara, J.M. Basset, Chem. Rev.
111 (2011) 3036–3075.
[45] G.J.J. Chen, J.W. McDonald, W.E. Newton, Inorg. Chem. 15 (1976) 2612–2615.
[46] J. Chisem, I.C. Chisem, J.S. Rafelt, D.J. Macquarrie, J.H. Clark, Chem. Commun.
(1997) 2203–2204.
[47] M. Ma, Y. Zhang, W. Yu, H. Shen, H. Zhang, N. Gu, Colloids Surf.
A: Physicochem. Eng. Asp. 212 (2003) 219–226.
[48] J. Topich, Inorg. Chem. 20 (1981) 3704–3707.
[49] R.A. Sheldon, J.A. Vandoorn, J. Catal. 31 (1973) 427–437.