Journal of Organometallic Chemistry
CoFe O @SiO : A magnetically recyclable heterogeneous catalyst for
2
4
2
the synthesis of spirooxindole derivatives
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Kaveh Hemmat , Mohammad Ali Nasseri, Ali Allahresani, Samaneh Ghiami
Department of Chemistry College of Sciences, University of Birjand, Birjand, 97175-615, Iran
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 6 September 2019
Received in revised form
We described the characterization, preparation, and catalytic application of CoFe O @SiO nanoparticle.
2
4
2
The characterization was done using transmission electron microscopy (TEM), vibrating sample
magnetometer (VSM), scanning electron microscopy coupled with energy dispersive X-ray (SEM-EDX),
and Fourier transform infrared (FT-IR) analyses. Using Scherrer’s approximation and powder X-ray
diffractometry (XRD), an average crystallite size is determined from the full width at half the maximum
of the strongest reflection. In the synthesis of spirooxindoles of malononitrile, various isatins with 1,3-
16 October 2019
Accepted 19 October 2019
Available online 22 October 2019
dicarbonyl compounds, The CoFe
observed in the coupling products, which was in result of excellent catalytic activity of the nanocatalyst.
Furthermore, at least five times of the recoverability and reusability of CoFe @SiO without any
2 4 2
O @SiO efficiency is investigated. Good to excellent yields are
Keywords:
Cobalt ferrite-silica
Isatin
O
2 4
2
Malononitrile
Dimedone
Spirooxindole
apparent decrease in the activity and selectivity are confirmed. This confirmed the high efficiency and
stability of the nanocatalyst under the reaction conditions and during the recycling stages.
© 2019 Published by Elsevier B.V.
1. Introduction
effectively protect the inner magnetite core [10e20]. Due to the
frequent presence in numerous natural and synthetic products
Due to their unique advantage of providing different function-
alities into a single entity, Nanocomposites (NCs) with core-shell
structures have attracted much interest. Magnetic core-shell NCs
have been commonly used in catalysis, biosensors, selective sepa-
ration, drug targeting, etc. as an important family of functionalized
materials [1e4]. In the field of magnetic NPs, due to their high
chemical and corrosive stability, moderate saturation magnetiza-
along with useful biological activities, oxindoles are very important
in heterocyclic chemistry. In biologically active and natural com-
pounds such as antibacterial, antiprotozoal, anti-inflammatory ac-
tivities and, progesterone receptors (PR) agonists, oxindole
derivatives are often considered as important structural compo-
.
nents [19e23]. Isatin, malononitrile and dimedone reaction in the
presence of GN/SO
Sodium stearate [28], TEBA [29], AIUM [30], B-CD [31], DES [32], Ni
NPS [33], SBA-PR-NH [34] and NEt [35] are several procedures of
3 2 4
H [24], ZnFe O [25], Borax [26], Al-ITQ-HB [27],
tion [5e7], easy preparation, and rapid separation [8,9], CoFe
nanoparticles (NPs) have received much attention when compared
with some magnetic materials, however, pure CoFe NPs may
2 4
O
2
3
2
O
4
this strategy which have been recently reported in the literatures.
In the present paper, continuing our ongoing research on the
development of eco-friendly organic synthesis, especially by nano-
catalysts [36e46], silica-coated cobalt ferrite nanoparticle
form a large aggregation with fewer activating group. They also
easily dissolved in an acid medium. Coating magnetic NPs with a
suitable biocompatible material, including activated carbons, clays,
silicas, and zeolites, is an important step in applications. A stable
suspension and possession of great biological compatibility are two
important characteristics of these materials. In addition to easy
functionalization of amorphous silica particles with hydroxyl
groups, due to its stability under acidic conditions and inertia to the
2 4 2
(CoFe O @SiO ) is introduced as an efficient, active and recyclable
magnetic nanocatalyst. In green processes, the nanocatalyst can be
used for different organic functional group transformations. Its
catalytic activity is also studied in the spirooxindoles synthesis by
the various isatins coupling with 1,3-dicarbonyl compounds and
malononitrile. It is found that the yield and selectivity of the cor-
responding delivered products are high to excellent. Also, unique
advantages including high magnetic property, simple catalyst
synthesis, easy catalyst separation using a permanent magnet, and
inexpensive and available precursors are also presented. Moreover,
2
redox reaction, SiO is an ideal shell composite that could
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022-328X/© 2019 Published by Elsevier B.V.
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