Synthesis of Fe3O4-supported Schiff base Cu (II) complex: a novel efficient and recyclable magnetic nanocatalyst for one-pot three-component synthesis of quinolin-5-one, chromene-3-carbonitrile and phthalazine-5,10-dione derivatives

Article abstract of DOI:10.1007/s11164-020-04293-7

In this research, synthesis and characterization of a novel Schiff base Cu (II) complex immobilized on Fe₃O₄@SiO₂ nanoparticles are reported. Then, the catalytic activity of these nanoparticles as magnetic recyclable nanocatalyst was explored for the one-pot three-component synthesis of quinolin-5-one, chromene-3-carbonitrile and phthalazine-5,10-dione derivatives. The reactions proceeded smoothly to provide the respective products in excellent yields under green conditions. Facile preparation of the catalyst, high yields of the products, low reaction times, and use of water as green solvent are the main advantages of the present protocol. Moreover, the catalyst can be easily separated from the reaction mixture in a magnetic field, recycled and reused for six consecutive fresh runs without considerable loss of catalytic activity. Graphic abstract: [Figure not available: see fulltext.]

Full text of DOI:10.1007/s11164-020-04293-7

Research on Chemical Intermediates
https://doi.org/10.1007/s11164-020-04293-7
Synthesis of Fe3O4‑supported Schif base Cu (II) complex:
a novel efcient and recyclable magnetic nanocatalyst
for one‑pot three‑component synthesis of quinolin‑5‑one,
chromene‑3‑carbonitrile and phthalazine‑5,10‑dione
derivatives
Hakimeh Ebrahimiasl1 · Davood Azarifar1 · Mahsa Mohammadi1,2,3
Hassan Keypour1 · Masoumeh Mahmood abadi1
·
Received: 4 August 2020 / Accepted: 3 October 2020
© Springer Nature B.V. 2020
Abstract
In this research, synthesis and characterization of a novel Schif base Cu (II) com-
plex immobilized on Fe3O4@SiO2 nanoparticles are reported. Then, the catalytic
activity of these nanoparticles as magnetic recyclable nanocatalyst was explored for
the one-pot three-component synthesis of quinolin-5-one, chromene-3-carbonitrile
and phthalazine-5,10-dione derivatives. The reactions proceeded smoothly to pro-
vide the respective products in excellent yields under green conditions. Facile prepa-
ration of the catalyst, high yields of the products, low reaction times, and use of
water as green solvent are the main advantages of the present protocol. Moreover,
the catalyst can be easily separated from the reaction mixture in a magnetic feld,
recycled and reused for six consecutive fresh runs without considerable loss of cata-
lytic activity.
Electronic supplementary material The online version of this article (https://doi.org/10.1007/s1116
4-020-04293-7) contains supplementary material, which is available to authorized users.
*
Hakimeh Ebrahimiasl
h_ebrahimiasl64@yahoo.com
1
2
Department of Chemistry, Bu-Ali Sina University, 65178 Hamedan, Iran
Pharmaceutical Sciences Research Center, School of Pharmacy, Health Institute, Kermanshah
University of Medical Sciences, Kermanshah, Iran
3
Department of Medicinal Chemistry, Faculty of Pharmacy, Kermanshah University of Medical
Sciences, Kermanshah, Iran
Vol.:(0123456789)
1 3

H. Ebrahimiasl et al.
Graphic abstract
Keywords Fe3O4-supported cu (II) Schif–base complex · Magnetic nanoparticles ·
Multicomponent reaction · Quinolin-5-one · Chromene-3-carbonitrile · Phthalazine-
5,10-dione
Introduction
In chemistry, quite often, ligands include with a ring size of nine or more atoms
(containing hetero atoms) and contain at least three donor sites [1]. So far, a vari-
ety of synthetic and natural compounds such as crown ethers, Schif bases and por-
phyrins have been investigated [2]. Several compounds and their derivatives exhibit
high afnity for metal ions and host various neutral molecules and organic cation
guests and are also useful in phase transfer catalysis and biological studies [3, 4].
In recent years, the chemistry of transition metal ion-based complexes of ligands
has attracted enormous interest in the feld of coordination chemistry [5–7]. Many
transition metals prompted Schif base complexes have been reported to perform
the excellent catalytic activity in various homogeneous and heterogeneous reactions
[8]. However, these Schif base complexes generally sufer from certain drawbacks
including instability, expensive and tedious purifcation steps, inefcient recycling
1 3

Synthesis of Fe3O4‑supported Schif base Cu (II) complex:…
and reusability. One recently emerged useful strategy to overcome these drawbacks
is the immobilization of Schif base complexes and other homogeneous catalysts
onto diferent support materials such as inorganic silica, organic polymers and nano-
sized metal oxides [9, 10]. The immobilization incorporates all the advantages of
both heterogeneous and homogeneous catalysts to provide the catalysts with highly
improved stability and catalytic activity [9]. Among the frequently used nano-sup-
ports, magnetic nanoparticles (MNPs) have emerged as excellent candidates because
of their heterogeneous and magnetic nature, high surface area, environmental benig-
nity, facile magnetic separation and efcient recyclability [11–14].
Schif bases are well-reported compounds carrying imine or azomethine (C=N)
functional group and form an important class of the most widely used organic com-
pounds [15, 16]. Schif bases have gained growing importance due to their broad
spectrum of biological activities and wide applications in many diferent felds
including medicinal, pharmaceutical, analytical, and inorganic chemistry [17–19].
Besides, Schif bases are used as catalysts, intermediates in organic synthesis and
the preparation of several industrial products like dyes, pigments, polymer stabiliz-
ers [16], and corrosion inhibitors [20]. Within the last few decades, several tran-
sition metal Schif base complexes have been synthesized and their importance in
biochemical, catalytic and industrial processes has been widely investigated [1, 2,
21–27]. Moreover, transition metal Schif base complexes have gained enormous
interest owing to their biological activities as anticarcinogenic, antiviral [28], antif-
ertile [29], antifungal and antibacterial agents [30]. Many diferent Cu (II) Schif
base complexes, such as Cu (II) isatin Schif base complexes, have been known as
potential antitumor agents [31]. Among several transition metals vitally important to
the chemistry of living systems, copper is by far the most familiar and widespread
example which performs an important biological function in living organisms and
found in plants and numerous proteins. Moreover, a large number of nanoparti-
cles based on the earth-abundant and inexpensive copper metal have found wide
applications in the feld of catalysis due to their interesting features including low
price, facile separation and high catalytic performance [32, 33]. Copper complexes
immobilized on Fe3O4 nanoparticles have exhibited high catalytic performance for a
wide range of organic transformations like oxidation, C–C coupling and condensa-
tion reactions [34–37]. A variety of Cu complexes supported on the magnetic nano-
particles as catalysts such as γ‐Fe2O3–Cu‐complex [38], Cu-SPATB/Fe3O4 [39],
Cu/imine@Fe3O4 MNPs [40], and Cu-HB@AS-MNPs [41] have been reported
in the literature. Based on these reports, it is understood that a new window has
been opened on the Fe3O4-supported Schif base complexes of Cu as catalysts in
one-pot multicomponent reactions. Multicomponent reactions (MCRs) have gained
enormous interest as an especially useful synthetic strategy with high diversity in
the reactions combining economic aspects with environmental anxiety [42]. MCRs
involve two or more steps that accomplish by successive reactions between three or
more reactants without separation of the intermediates. As a result, the MCRs ben-
eft from several advantages such as waste prevention, atom-economy, energy ef-
ciency, yield improvement, and short reaction times [43].
In the last few decades, the one-pot multicomponent reactions have found wide
applications in synthetic chemistry particularly for the synthesis of a wide variety
1 3

H. Ebrahimiasl et al.
of biologically active heterocyclic compounds [44]. The most frequently used
therapeutic pharmaceuticals worldwide contain certain heterocyclic scafolds as
the key structural units. Among the heterocyclic compounds of biological impor-
tance, coumarin, pyrroloquinoline and phthalazine nucleus are of considerable
signifcance owing to their presence in biologically active compounds, pharma-
ceuticals, the broad range of natural products and functional materials [45–48].
Considering the broad range applications of the coumarin, pyrroloquinoline
and phthalazine derivatives, a great interest has been focused on the development
of more efcient and eco-friendly protocols for the synthesis of these compounds.
This prompted us to synthesis a novel nanomagnetic copper (II) complex using
Schif base ligand as a heterogeneous and reusable catalyst in the synthesis of
organic compounds. In continuation of our research program in developing more
efcient and recyclable catalysts and, also environmentally friendly protocols for
the synthesis of heterocyclic compounds, herein, we report the design, synthesis
and characterization of the Schif base Cu (II) complex immobilized on the sur-
face of Fe3O4@SiO2 MNPs (Scheme 1) and its application as a reusable nano-
catalyst for one-pot three-component and solvent-free synthesis of [3,2-c]quin-
olin-5-one, [3,2-c]chromene-3-carbonitrile and [1,2-b]phthalazine-5,10-dione
derivatives (Scheme 2). Also, thanks to facile synthesis of catalyst support, easy
accessibility and low price of copper (Cu) source, we were able to synthesize this
new nanocatalyst on a large scale.
Scheme 1 Immobilization process of Schif base and its Cu(II) complex on Fe3O4–SiO2
1 3

Synthesis of Fe3O4‑supported Schif base Cu (II) complex:…
Scheme 2 Three-component synthesis of various [3,2-c]quinolin-5-one, [3,2-c]chromene-3-carbonitrile
and [1,2-b]phthalazine-5,10-dione derivatives catalyzed by Fe3O4@SiO2@CPTES@Cu(II) Schif base
complex MNPs
Experimental
Materials
Starting materials and used solvents were purchased from Merck Chemical Com-
pany and used without further purifcation.
Characterization techniques
Melting points were determined in open capillary tubes using a BUCHI 510 appara-
tus. Fourier transform infrared (FT-IR) spectra were recorded from KBr pellets on a
PerkinElmer GX FT-IR spectrometer. 1H NMR and 13C NMR spectra were recorded
for samples in DMSO-d6 on 90, 400 and 500 MHz Bruker Avance instruments at
ambient temperature using tetramethylsilane (TMS) as the internal standard. Scan-
ning electron microscopy (SEM) images were obtained on EM3200 instrument
operated at 30 kV accelerating voltage. Energy-dispersive X-ray (EDX) analysis
was carried out using a FESEM-SIGM (German) instrument. The curves obtained
from thermo-gravimetric analysis (TGA) were recorded in the air using TGA/DTA
Pyris Diamond instrument. Magnetic measurement of the catalyst was taken using a
vibrating sample magnetometer (VSM) instrument MDKFT. Moreover, transmission
1 3

H. Ebrahimiasl et al.
electron microscopy (TEM) was performed using a Zeiss‐EM10C‐100kv CM30,
(300KV) instrument. Wavelength‐ dispersive X‐ray spectroscopy (WDX) was per-
formed using a TESCAN mira3. Inductively coupled plasma optical emission spec-
troscopy (ICP‐OES) was performed by Arcos EOP, 32 Linear CCD simultaneous
ICP analyzer.
Synthesis
Synthesis of the Schif base ligand (III)
For the synthesis of the Schif base ligand (III), 2-((4-(2-aminobenzyl)-1,4-diazepan-
1-yl)methyl)benzenamine ( 0.31 g, 1 mmol) dissolved in ethanol (20 mL) was added
dropwise with stirring to a solution of 2-Pyridinecarboxaldehyde ( 0.2 g, 2 mmol)
in ethanol (20 mL) (Scheme 3) [49]. The mixture was stirred and refuxed for 24 h.
After the completion of the reaction, the orange Schif base (III) was recovered by
simple fltration and then repeatedly washed with cold methanol, and dried in vac-
uum to yield the desired product (Scheme 2). Yield: 0.26 g (86%). M.p: 112 °C.
Anal. Calc. for C31H32N6 (M. W: 488.27): C, 76.20; H, 6.60; N, 17.20. Found: C,
76.32; H, 6.45; N, 17.33%. EI-MS (m/z): 488.27. IR (KBr, cm−1) ν: 1628 (C=N),
1
1606, 1587 [(C=C) and (C=N)Py]. H NMR (DMSO-d6, ppm) δc: 1.762–1.795 (m,
2Ha), 2.708–2.727 (t, 4Hb), 3.595–3.609 (d, 4Hc), 3.812 (s, 4Hd), 6.940–8.260 (m,
16HAro), 8.515 (s, 2Hk).13C NMR (DMSO-d6, ppm) δc: 27.5 (Ca), 56.7 (Cb), 59.71
(Cc), 59.13(Cd), 118.47–149.1 (CAro), 151.9 (Ck).
Synthesis of the Fe3O4 and Fe3O4@SiO2
Nano-magnetic Fe3O4 were prepared by co-precipitation of Fe3+ and Fe2+ ions with
[Fe3+]/[Fe2+] molar ratio of 2:1 as described according to the reported method [50].
Briefy, FeCl3.6H2O (5.4 g, 0.02 mol) and FeCl2.4H2O (2.0 g, 0.01 mol) were stir-
ring and dissolved in deionized water (80 mL) under N2 fow and vigorous stirring
Scheme 3 Synthesis of the Schif base ligand (III)
1 3

Synthesis of Fe3O4‑supported Schif base Cu (II) complex:…
conditions. Then a solution of NH4OH (25%, 15 mL) was rapidly added to the mix-
ture at 80 °C to form black Fe3O4 magnetic nanoparticles. The Fe3O4 NPs were
fltered and washed several times with H2O and EtOH and at the end stored in a
vacuum desiccator at 4 ˚C for using in further. The Fe3O4@SiO2 were prepared
according to the Stober method [51]. Fe3O4 particles (100 mg) were suspended in
a mixture of 100 mL of ethanol 10 mL of deionized water in (25 mL) round-bottom
fask and then tetraethyl orthosilicate (TEOS) was dispersed in the reaction mixture
and stirred for 2 h at room temperature to facilitate TEOS coating. The dark-brown
precipitate was separated using a magnet and washed several times with ethanol to
aford the desired product.
Synthesis of the Fe3O4@SiO2@CPTES
To form Fe3O4@SiO2@CPTES, Fe3O4@SiO2 was modifed with 3-chloropropyltri-
ethoxysilane (CPTES) [52]. In short, 100 mg of the Fe3O4@SiO2 was added to dry
toluene (100 mL) in a round-bottom fask and then to CPTES (3 mL) was put in the
reaction under N2 atmosphere and stirred at 90 °C for 12 h. The product (Fe3O4@
SiO2@CPTES) was obtained by separation with a magnet and washed with toluene
three times and stored for further use.
Synthesis of the Fe3O4@SiO2@CPTES@ Schif base
Functionalization of Fe3O4@SiO2@CPTES was performed by a Schif base ligand
(III). In brief, for the synthesis of Fe3O4@SiO2@CPTES@ Schif base, the Fe3O4@
SiO2@CPTES (100 mg) was dispersed in CH3CN (25 mL). Then, a solution of the
Schif base ligand (III) (1 mmol) in acetonitrile (5 mL) was added to a mixture of
the Fe3O4@SiO2@CPTES and refuxed for 24 h under N2. Ultimately, the Fe3O4@
SiO2@CPTES@ Schif base was separated with an external magnet and washed
with acetonitrile 3 times until the product obtained and dried under vacuum for 24 h.
Synthesis of the Fe3O4@SiO2@CPTES@Cu(II) Schif base complex NPs
Fe3O4@SiO2@CPTES@Cu(II) Schif base complex NPs were prepared by using a
simple refux method. The dissolved solution of Cu(OAc)2 (5% (w/v)) in ethanol
(5 mL) was slowly added to the Fe3O4@SiO2@CPTES@ Schif base (50 mg) solu-
tion in ethanol (20 mL) under constant stirring and refuxed for 24 h. The obtained
product was washed with ethanol to remove unreacted Cu(OAc)2 and dried in a vac-
uum oven at 60 °C for 5 h (Scheme 1).
Overall template synthesis of dihydropyrano[3,2‑c]chromen‑2‑one,
2‑amino‑3‑cyano‑1,4,5,6‑tetrahyropyrano[3,2‑c]quinolin‑5‑one
and 1H‑pyrazolo[1,2‑b]phthalazine‑5,10‑diones derivatives
A
mixture of aromatic aldehyde (1 mmol), malononitrile (1 mmol),
4-hydroxycoumarin/4-hydroxyquinolin-2(1H)-one/ phthalhydrazide (1 mmol)
1 3

H. Ebrahimiasl et al.
and nano-catalyst (30 mg) was stirred at 80 °C under the solvent-free condition
for 10–15 min (Scheme 3). After completion (by TLC), the resulting solid was
diluted with hot ethanol (5 mL) and the catalyst was isolated by an external mag-
net. The obtained precipitate was purifed by simple recrystallization in EtOH to
yield the pure product. The structures of the products were established on their
1
melting points and spectral (FT-IR, H NMR and 13C NMR) analysis and com-
pared with the reported data (Tables 1 and 2). The structure of the synthesized
products was confrmed by 1H NMR, 13C NMR and IR (Supporting Information).
Spectral selected data
2‑Amino‑4,5‑dihydro‑4‑(4‑hydroxyphenyl)‑5‑oxopyrano[3,2‑c]
chromene‑3‑carbonitrile (4b)
Cream solid; m.p. 262‐264 °C; IR (KBr) (νmax/cm−1): 3504, 3407, 3283, 2196,
1696, 1673, 1609 cm−1; H‐NMR (90 MHz, DMSO‐d6) δ: 4.31 (s, 1H, C‐H),
6.62‐7.91 (m, 10H, H‐Ar and NH2), 9.34 (s, 1H, O‐H) ppm.
Table 1 Optimization reaction for the synthesis of 2-amino-5-oxo-4-phenyl-4H,5Hdihydropyrano[3,2-c]
chromene-3-carbonitrile derivatives
NH2
OH
NC
O
CN
CN
Nanocatalyst (?)
O
H
O
O
Temperature (?)
Solvent (?)
O
O
4a
Entry
Catalyst amount (mg)
Solvent
Temperature (°C)
Time (min)
Yield a
1
2
3
4
5
6
7
8
No catalyst
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.02
0.03
0.04
H2O
H2O
EtOH
CH3CN
Solvent-Free
H2O
25
25
25
25
120
120
90
60
50
60
60
60
40
40
15
10
10
–
30
32
50
58
45
62
68
72
75
97
98
85
25
Refux
Refux
Refux
70
100
80
EtOH
CH3CN
9
Solvent-free
Solvent-free
Solvent-free
Solvent-free
Solvent-free
10
11
12
13
80
70
Reaction Condition: benzaldehyde (1 mmol), 4-hydroxycoumarin (1 mmol), malononitrile (1 mmol), sol-
vent (5 ml), aIsolated yields
1 3

Synthesis of Fe3O4‑supported Schif base Cu (II) complex:…
Table 2 Fe3O4@SiO2@CPTES@Cu (II) Schif base complex catalyzed synthesis of synthesis of 5-oxo-
dihydropyrano[3,2-c]chromene and 2-amino-3-cyano-1,4,5,6-tetrahydropyrano[3,2-c]quinolin-5-one
derivatives
NH2
O
CN
OH
O
X
H
Nanocatalyst: 30 mg
Solvent-free, 80 °C
O
x
R
X
O
NC
X
O
CN
Entry
1
R
H
Product
Time (min)
Yieldb (%)
98
M.P (°C) [Lit.]
[53–58]
NH2
10
15
15
252–254
262–264
240–242
CN
O
O
O
4a
NH2
2
3
4-OH
O
O
90
89
CN
O
OH
O
4b
O
NH2
4-OCH3
CN
O
OCH3
O
4c
O
NH2
4
4-CH3
O
15
92
250–252
CN
O
O
CH3
O
4d
NH2
5
6
2-Cl
O
O
10
10
97
97
260–262
252–254
CN
O
Cl
O
4e
O
NH2
2-NO2
CN
O
NO2
O
O
4f
NH2
7
8
4-Br
O
O
10
10
96
97
255–257
254–256
CN
O
Br
O
4g
O
NH2
2,4-Cl2
CN
O
Cl
Cl
O
O
4h
1 3

H. Ebrahimiasl et al.
Table 2 (continued)
NH2
O
CN
OH
O
X
H
Nanocatalyst: 30 mg
Solvent-free, 80 °C
O
x
R
X
O
NC
CN
Entry
9
R
H
X
Product
Time (min)
Yieldb (%)
96
M.P (°C) [Lit.]
[53–58]
NH2
NH
10
>300
CN
O
N
H
O
4i
NH2
10
11
4-CH3
4-Br
NH
NH
15
10
90
97
>300
>300
CN
O
CH3
N
H
4j
O
NH2
CN
O
Br
N
H
O
4k
Conditions: aldehyde (1 mmol), malononitrile (1 mmol), 4-hydroxycoumarin/4-hydroxyquinolin-2(1H)-
one (1 mmol), catalyst (30 mg), 80 °C, aIsolated pure yield
2‑Amino‑4,5‑dihydro‑4‑(4‑methoxyphenyl)‑5‑oxopyrano[3,2‑c]
chromene‑3‑carbonitrile (4c)
Cream solid; m.p. 240‐242 °C; IR (KBr) (νmax/cm−1): 3389, 3293, 2195, 1715, 1676,
1605 cm‐1; 1 H‐NMR (90 MHz, DMSO‐d6) δ: 4.70 (s, 1H, C‐H), 6.78‐7.94 (m, 10H,
H‐Ar and NH2), 3.70 (s, 3H, OCH3) ppm.
2‑Amino‑4‑(2‑chlorophenyl)‑4,5‑dihydro‑5‑oxopyrano[3,2‑c]
chromene‑3‑carbonitrile (4e)
Cream solid; m.p. 260‐262 °C; IR (KBr) (νmax/cm−1): 3407, 3324, 2192, 1711, 1608,
1
1528 cm‐1; H‐NMR (400 MHz, DMSO‐d6) δ: 4.98 (s, 1H, C‐H), 7.35‐7.92 (m,
10H, H‐Ar and NH2) ppm; 13C‐NMR (400 MHz, DMSO‐d6) δ: 36.4, 56.6, 103.1,
112.8, 116.5, 118.6, 122.5, 122.8, 124.6, 128.2, 129.0, 130.6, 132.7, 133.0, 135.5,
152.1, 153.9, 158.0, 159.3 ppm.
1 3

Synthesis of Fe3O4‑supported Schif base Cu (II) complex:…
2‑Amino‑4,5‑dihydro‑4‑(2‑nitrophenyl)‑5‑oxopyrano[3,2‑c]
chromene‑3‑carbonitrile (4f)
Cream solid; m.p. 252‐254 °C; IR (KBr) (νmax/cm−1): 3401, 3312, 2193, 1702, 1674,
1607 cm‐1; 1 H‐NMR (90 MHz, DMSO‐d6) δ: 5.23 (s, 1H, C‐H), 7.56‐8.00 (m, 10H,
H‐Ar and NH2) ppm.
2‑Amino‑4‑(4‑bromophenyl)‑4,5‑dihydro‑5‑oxopyrano[3,2‑c]
chromene‑3‑carbonitrile (4 g)
Cream solid; m.p. 255–257 °C; IR (KBr) (νmax/cm−1): 3386, 3312, 3187, 2191,
1
1716, 1676, 1608; H‐NMR (400 MHz, DMSO‐d6) δ: 4.5 (s, 1H, C-H), 7.28–7.91
(m, 10H, Ar–H and NH2) ppm; 13C NMR (100 MHz, DMSO-d6) δ 34.3, 56.4,
102.9, 103.3, 117.1, 119.3, 123.01, 125.2, 128.3, 129.3, 132.6, 133.6, 133.8, 139.9,
152.7, 154.6, 158.5, 158.4, 159.9 ppm.
2‑Amino‑4‑(2,4‑dichlorophenyl)‑4,5‑dihydro‑5‑oxopyrano[3,2‑c]
chromene‑3‑carbonitrile (4 h)
Cream solid; m.p. 254‐256 °C; IR (KBr) (νmax/cm−1): 3460, 3294, 2200, 1716,
1674, 1630 cm‐1; 1 H‐NMR (400 MHz, DMSO‐d6) δ: 4.98 (s, 1H, C-H), 7.35–7.92
(m, 9H, H-Ar and NH2) ppm; 13C‐NMR (100 MHz, DMSO‐d6) δ: 34.3, 56.4, 102.9,
113.3, 114.1, 119.1, 123.0, 125.2, 128.3, 129.3, 132.5, 132.8, 133.6, 133.8, 139.9,
152.9, 154.6, 158.5, 158.6, 159.9 ppm.
2‑Amino‑5,6‑dihydro‑5‑oxo‑4‑p‑tolyl‑4H‑pyrano[3,2‑c]quinoline‑3‑carbonitrile
(4j)
Pale yellow powder; mp>300; IR (KBr) (νmax/cm−1): 3410, 3284, 3163, 2189,
1668, 1384, 1365 cm‐1; 1 H‐NMR (500 MHz, DMSO‐d6) δ: 2.24 (s, 3H, C-H), 4.44
(s, 1H, C-H), 7.08 (s, 4H, H-Ar), 7.23 (s, 2H, NH2), 7.25–7.38 (m, 2H, H-Ar), 7.58
(t, J=7.7 Hz, 1H, H-Ar), 7.90 (d, J=7.9 Hz, 1H, H-Ar), 11.76 (s, 1H, NH) ppm; 13
C
NMR (125 MHz, DMSO-d6) δ: 21.0, 36.7, 58.4, 110.2, 112.5, 115.7, 120.2, 122.2,
122.3, 127.7, 129.3, 131.5, 136.2, 138.2, 141.8, 151.5, 159.4, 160.9 ppm.
2‑Amino‑4‑(4‑bromophenyl)‑5,6‑dihydro‑5‑oxo‑4H‑pyrano[3,2‑c]
quinoline‑3‑carbonitrile (4 k)
Pale yellow powder; mp>300 °C; IR (KBr) (νmax/cm−1): 3404, 3287, 3173, 2188,
1672, 1321, 1379 cm‐1; 1 H‐NMR (500 MHz, DMSO‐d6) δ: 4.49 (s, 1H, C-H), 7.17
(d, J=8.4 Hz, 4H, H-Ar), 7.28–7.35 (s, 2H NH2), 7.47 (d, J=8.4 Hz, 2H, H-Ar),
7.60 (t, J=16.4, 8.2 Hz, 1H, H-Ar), 7.91 (d, J=7.9 Hz, 1H, H-Ar), 11.80 (s, 1H,
NH) ppm; 13C NMR (125 MHz, DMSO-d6) δ: 36.7, 57.7, 109.4, 112.3, 115.8, 120.0,
120.2, 122.2,122.4, 130.1, 131.6, 131.7, 138.3, 144.2, 151.7, 159.3, 160.8 ppm.
1 3

H. Ebrahimiasl et al.
3‑Amino‑5,10‑dihydro‑5,10‑dioxo‑1‑phenyl‑1H‑pyrazolo[1,2‑b]
phthalazine‑2‑carbonitrile (6a)
Yellow solid; m.p. 272‐274 °C; IR (KBr) (νmax/cm−1): 3361, 3316, 2197, 1682,
1660 cm‐1; 1 H‐NMR (90 MHz, DMSO‐d6) δ: 6.12 (s, 1H, C‐H), 7.37‐8.00 (m, 11H,
H‐Ar and NH2) ppm; 13C NMR (100 MHz, DMSO-d6) δ: 39.5, 61.4, 62.9, 116.0,
126.6, 138.4, 150.6, 153.6, 156.6 ppm.
3‑Amino‑5,10‑dihydro‑5,10‑dioxo‑1‑p‑tolyl‑1H‑pyrazolo[1,2‑b]
phthalazine‑2‑carbonitrile (6b)
Yellow solid; m.p. 256‐258 °C; IR (KBr) (νmax/cm−1): 3363, 3262, 2197, 1656,
1567 cm‐1; 1 H‐NMR (90 MHz, DMSO‐d6) δ: 2.28 (s, 3H, C-H), 6.08 (s, 1H, C‐H),
7.10‐8.20 (m, 10H, H‐Ar and NH2) ppm.
3‑Amino‑5,10‑dihydro‑1‑(4‑methoxyphenyl)‑5,10‑dioxo‑1H‑pyrazolo[1,2‑b]
phthalazine‑2‑carbo‑nitrile (6c)
Yellow solid; m.p. 240‐242 °C; IR (KBr) (νmax/cm−1): 3376, 3308, 2197, 1677,
1
1661 cm‐1; H‐NMR (400 MHz, DMSO‐d6) δ: 3.80 (s, 3H, OCH3), 6.15 (s, 1H,
CH), 6.95–8.31 (m, 10H, H-Ar and NH2) ppm, 13C NMR (100 MHz, DMSO-d6) δ:
55.1, 61.3, 62.6, 113.8, 116.1, 125.1, 126.6, 127.2, 128.5 128.7, 130.1, 132.5, 133.7,
134.6, 150.6, 153.6, 156.6, 159.2 ppm.
3‑Amino‑1‑(2,4‑dichlorophenyl)‑5,10‑dihydro‑5,10‑dioxo‑1H‑pyrazolo[1,2‑b]
phthalazine‑2‑carbo‑nitrile (6d)
Yellow solid; m.p. 246‐248 °C; IR (KBr) (νmax/cm−1): 3370, 3360, 2204, 1676,
1632 cm‐1; 1 H‐NMR (400 MHz, DMSO‐d6) δ: 6.48 (s, 1H, CH), 7.35–8.27 (m, 9H,
H-Ar and NH2) ppm, 13C NMR (100 MHz, DMSO-d6): δ 39.5, 59,7, 60,6, 116.0,
125.5, 135.2, 151.7, 154.0, 157.1 ppm.
3‑Amino‑5,10‑dihydro‑5,10‑dioxo‑1‑(pyridin‑4‑yl)‑1H‑pyrazolo[1,2‑b]
phthalazine‑2‑carbonitrile (4f)
Yellow solid; m.p. 260‐262 °C; IR (KBr) (νmax/cm−1): 3388, 3285, 2198, 1681,
1
1664, 1604, 1579 cm‐1; H‐NMR (400 MHz, DMSO‐d6) δ: 6.21 (s, 1H, CH),
7.57–8.64 (m, 10H, H-Ar and NH2) ppm, 13C NMR (100 MHz, DMSO-d6) δ: 60.1,
61.7, 115.7, 121.3, 126.7, 127.2, 128.3, 128.9, 133.8, 134.6, 147.1, 149.9, 150.9,
153.7, 156.7 ppm.
1 3

Synthesis of Fe3O4‑supported Schif base Cu (II) complex:…
Results and discussion
Preparation of the novel copper(II) complexes using Schif base ligand‑coated
Fe3O4 nanoparticles as catalyst
Herein, we report the stepwise synthesis of hitherto unexplored Fe3O4-supported
copper (II) Schif base complex Fe3O4@SiO2@CPTES@Cu(II) Schif base com-
plex NPs as an efcient and recyclable heterogeneous nano-catalyst as explained
above (Scheme 1). In frst, preparation of the Schif base ligand (II) is similar to
the reported method [20] (Scheme 2). Then, the silica-coated Fe3O4 MNPs were
prepared by co‐precipitation of ferrous (Fe2+) and ferric (Fe3+) ions followed
by the reaction of dispersion of the resulted nanoparticles in ethanol and deion-
ized water with tetraethyl orthosilicate (TEOS) in the presence of 25% ammo-
nia solution to obtain the core–shell Fe3O4@SiO2 nanoparticles. In the next step,
the Fe3O4@SiO2 nanoparticles were reacted with (3-chloropropyl)triethoxysilane
(CPTES) in dry toluene under nitrogen atmosphere to obtain the chloro-function-
alized Fe3O4@SiO2@CPTES MNPs. Then, the reaction of Fe3O4@SiO2-(CH2)3-
Cl nanoparticles with Schif base ligand (II) in acetonitrile containing few drops
of triethylamine under a nitrogen atmosphere and refuxed condition furnished
the Fe3O4@SiO2@CPTES@ Schif base nanoparticles. In the last step, copper
(II) was supported on the surface of Schif‐ base‐modifed magnetic nanoparticles
via reaction with Cu(OAc)2 in ethanol under refux conditions.
Characterization of the catalyst Fe3O4@SiO2@CPTES@Cu (II) Schif base complex
NPs
Spectral measurements including FT-IR, XRD, SEM, TEM, EDX, TGA, Map-
ping, ICP and VSM analysis were used to characterize and establish the structure
of the heterogeneous nanocatalyst.
FT‑IR analysis
The infrared spectra of pure Fe3O4 (a), Fe3O4@SiO2 (b), Fe3O4@SiO2@CPTES
(c), Schif base (d), Fe3O4@SiO2@CPTES@ Schif base (e) and Fe3O4@SiO2@
CPTES@Cu (II) Schif base complex NPs (f) are illustrated in Fig. 1. The peak at
582 cm−1 in Fig. 1a was observed, corresponding to the Fe–O vibration at the mag-
netite phase. The Si–O absorption appearing at 1087 cm−1 confrms the successful
functionalization of the Fe3O4 with tetraethyl orthosilicate (Fig. 1b). A new peak
emerges at 2291 cm−1 corresponding to CH2 characteristic stretching band of the
Fe3O4@SiO2@CPTES (see Fig. 1c), indicating that the chloro-functional groups are
successfully grafted onto the surface of the magnetic Fe3O4@SiO2 NPs. There is a
sharp band in 1621, 1580 cm−1, attributed to C=N, indicating that Schif base con-
densation has occurred (see Fig. 1d). Also, the absorption band at about 1620 cm−1
is assigned that the Schif base functional groups are successfully immobilized on
the surface of the magnetic Fe3O4@SiO2@CPTES NPs (Fig. 1e). The C=N band
1 3

H. Ebrahimiasl et al.
Fig. 1 FT-IR spectra of a naked Fe3O4, b Fe3O4@SiO2, c Fe3O4@SiO2@CPTES, d ligand-Schif base, e
Fe3O4@SiO2@CPTES@ Schif base f Fe3O4@SiO2@CPTES@Cu (II) Schif base complex
shifts to a lower frequency in the spectrum 1f and deduces successful complexation
of Schif base to Copper (II) ion.
XRD analysis
X-ray difraction (XRD) patterns of Fe3O4 and Fe3O4@SiO2@CPTES@Cu (II)
Schif base complex NPs separately are identifed in Fig. 2. The obtained com-
parison results of XRD indicated that the crystalline structure of the Fe3O4 is still
maintained after each of immobilization steps (Fig. 2b). The peaks located at the
2θ values of 31.13, 35.69, 43.15, 52.61, 57.11 and 62.78 are attributed to novel
nano-catalyst.
Elemental analysis of the catalyst by EDS and ICP
Using the energy-dispersive X-ray spectroscopy (EDS) analysis, all related compo-
nents of the nano-catalyst including Si, C, O, Fe, Cu, N and Cl are observed (Fig. 3)
and proved that silica and organic layers are successfully loaded onto surface Fe3O4
nanoparticles. Besides, ICP-OES analysis of the catalyst specifed that the weight
percentage of Cu is 10.13%.
Scanning electron microscopy, transmission electron microscopy and mapping
analysis
The structural formation of the nano-catalyst was investigated using SEM, TEM
and mapping techniques discretely (Fig. 4). In the SEM image, Fig. 4a shows SEM
1 3

Synthesis of Fe3O4‑supported Schif base Cu (II) complex:…
Fig. 2 XRD patterns of a naked Fe3O4 MNPs and b Fe3O4@SiO2@CPTES@Cu (II) Schif base complex
Fig. 3 The energy dispersive X-ray (EDX) spectrum of Fe3O4@SiO2@CPTES@Cu (II) Schif base com-
plex
images of surface morphology of the nano-catalyst that the average size of these
MNPs is estimated to be about 40 nm. In the TEM image (Fig. 4b), there can be
seen various layers coated on the surface of the Fe3O4 nanoparticles. Furthermore,
the mapping image confrms the uniform distribution of these elements in the cata-
lyst structure (Fig. 4c).
1 3

H. Ebrahimiasl et al.
Fig. 4 a SEM, b TEM and c mapping images of the Fe3O4@SiO2@CPTES@Cu (II) Schif base complex
Vibrating‑sample magnetometer (VSM) analysis
The magnetic behavior of the Fe3O4 nanoparticles and the navel nano-catalyst is
shown in Fig. 5. The magnetization curves of Fe3O4 (Fig. 5a) and the navel nano-
catalyst (Fig. 5b) were found at 60 and 42 emu/g, separately. The observed results
elucidated that the magnetization value of Fe3O4 was lower than that of navel nano-
catalyst, due to the presence of silica-coated and surrounding Fe3O4-nanoparticles
cores.
Fig. 5 Magnetization curves of a bare Fe3O4 and b Fe3O4@SiO2@CPTES@Cu (II) Schif base complex
1 3

Synthesis of Fe3O4‑supported Schif base Cu (II) complex:…
Thermogravimetric analysis (TGA‑DTA)
The thermogravimetric analysis (TGA) was carried out from room temperature to
800 °C under atmosphere (Fig. 6) to investigate the thermal stability of the syn-
thesized nano-catalyst. According to the TGA curve, the initial weight loss was
observed at temperatures below 150 °C could be due to the adsorbed solvent or
removal adsorbed water from the nano-catalyst. A further decrease in weight
approximately 12% occurred between 250 and 429 °C which can be attributed to
loss and decompose of the organic groups on Fe3O4 surface. According to these
results, it can be concluded that adequate thermal stability for catalysis applications
is up to 250 °C.
Evaluation of the catalytic activity and recyclability of the Cupper
nano‑catalyst in the multicomponent synthesis via one‑pot reaction
After the design, synthesis and characterization of the nano-catalyst, we used
the nano-catalyst in the one‐pot synthesis of 5-oxo-dihydropyrano[3,2-c]
chromene, 2-amino-3-cyano-1,4,5,6-tetrahydropyrano[3,2-c] quinolin-5-one and
1H-pyrazolo[1,2-b]phthalazine-5,10-dione derivatives using the reaction between
various
aldehydes,
4-hydroxycoumarin/4-hydroxyquinolin-2(1H)-one/phthal-
hydrazide and malononitrile (Scheme 3). Initially, a mixture of benzaldehyde
Fig. 6 TGA-DTG curve of Fe3O4@SiO2@CPTES@Cu (II) Schif base complex MNPs
1 3

H. Ebrahimiasl et al.
(1 mmol), 4‐hydroxycoumarin (1 mmol) and malononitrile (1 mmol) was selected as
a model reaction. Consequently, the infuence of parameters such as catalyst concen-
tration, solvent and temperature was studied meticulously to achieve the best reac-
tion conditions. According to Table 1, the obtained results have shown that the best
conditions were carried out at 80 °C under the solvent‐free condition with using
30 mg of the nano-catalyst (Table 1, entry 12). Thus, optimized reaction conditions
with other aromatic aldehydes conducted were also similarly efective (Table 2).
All reactions were completed within 10–15 min and given excellent isolated yields
of products 4a–k. Similarly, to evaluate the best conditions for the synthesis of
3-amino-5,10-dihydro-5,10-dioxo-1-phenyl-1H-pyrazolo[1,2-b]phthalazine-2-car-
bonitrile, hereby the reaction was examined between benzaldehyde, malononitrile
and phthalhydrazide as model reaction under conditions such as refuxing and stir-
ring under various temperatures with diferent solvents (EtOH, H2O, CH3CN) or
solvent-free conditions using various amounts of the nano-catalyst (Table 3). The
model reaction was conducted with 30 mg of the nano-catalyst at 80 °C for 10 min
and furnished 6a with a 97% yield. Encouraged by these results, it was remarka-
bly realized and approved the important role of the nano-catalyst in this reaction by
conducting the reaction in the absence of the catalyst that obtained in no detectable
Table 3 Optimization reaction for the synthesis of 1H-pyrazolo[1,2-b]phthalazine-5,10-dione derivatives
O
O
NC
NH
NH
CN
O
Nanocatalyst (?)
N
N
CN
Temperature (?)
Solvent (?)
H
O
O
NH2
6a
Entry
Catalyst amount (mg)
Solvent
Temperature (°C)
Time (min)
Yield a
1
2
3
4
5
6
7
8
No catalyst
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.02
0.03
0.04
H2O
H2O
EtOH
CH3CN
Solvent-free
H2O
EtOH
25
25
25
25
120
120
90
60
50
60
60
60
40
40
10
10
10
–
30
35
50
65
45
62
68
72
80
95
97
85
25
Refux
Refux
Refux
70
100
80
CH3CN
9
Solvent-free
Solvent-free
Solvent-free
Solvent-free
Solvent-free
10
11
12
13
80
70
Reaction Condition: benzaldehyde (1 mmol), phthalhydrazide (1 mmol), malononitrile (1 mmol), solvent
(5 ml), aIsolated yields
1 3

Synthesis of Fe3O4‑supported Schif base Cu (II) complex:…
amount of the product after a prolonged reaction time (Table 3, entry 1). Moreover,
the catalytic activity of the Fe3O4@SiO2@CPTES@Cu(II) Schif base nanoparti-
cles was compared with the catalytic activities of the bare Fe3O4, Fe3O4@SiO2 and
Fe3O4@SiO2@CPTES supported Schif base nanoparticles in separate experiments
conducted under the same optimal conditions. The resulting yields given in Table 4
clearly indicated that the Fe3O4@SiO2@CPTES@Cu(II) Schif base nanoparticles
perform relatively higher catalytic activity compared with other three nanoparticles.
To expand the scope of this reaction, the variability of the aromatic aldehydes
was also synthesized in good yields and the short time that the results summarized
in Table 5. fnally, Benzaldehyde derivatives such as 2,4-Cl, 3-NO2, 4-C5H5N and
4-Cl-benzaldehyde undergo the reaction more readily than the aldehydes carrying
electron‐donating groups and aforded the desired products (6d–6 g) in very good
yields relatively (Table 5). All the synthesized molecules are known compounds
which were characterized using the usual spectroscopic techniques and compared
with the data reported in the literature and the experimental section supported our
spectroscopic data for some selected products. Since catalyst recovery and recycla-
bility are remarkable and important for industrial and commercial applications as
well as in green chemistry. Therefore, reusability and recovery of this nano-catalyst
were investigated in the reaction of benzaldehyde (1 mmol), malononitrile (1 mmol),
4-hydroxycoumarin/ phthalhydrazide (1 mmol) and nano-catalyst (30 mg) at 80 °C
under solvent-free (under optimized conditions). At the end of the reaction, the cat-
alyst was magnetically removed the reaction mixture and separated with the help
of an external magnet, washed with hot ethanol and dried. The nano-catalyst was
reused for six runs. The obtained results (FT-IR, EDX, XRD of reused catalyst in
the sixth run) had no distinct change in the structure and activity of the nano-catalyst
(Fig. 7).
Investigation of catalyst recyclability in the synthesis of 4a (I), 6a (II) under opti-
mized conditions.
Table 4 Comparative catalytic
Entry
1
Catalyst
Time (min)
10
Yield (%)
98
activity of Fe3O4@SiO2@
CPTES@ Cu(II) Schif base
nanoparticles under optimal
conditions
Fe3O4@SiO2@
CPTES@Cu(II)
Schif base
2
Fe3O4@SiO2@
CPTES@Schif
base
30
80
3
4
Fe3O4@SiO2
Fe3O4
120
35
58
70
1 3

H. Ebrahimiasl et al.
Table 5 Fe3O4@SiO2@CPTES@Cu (II) Schif base complex catalyzed synthesis of1H-pyrazolo[1,2-b]
phthalazine-5,10-dione derivatives
X
O
O
NC
NH
NH
CN
O
Nanocatalyst: 30 mg
Solvent-free, 80 °C
N
N
CN
H
O
NH2
O
X
Entry
1
X
H
Product
Time (min)
Yielda (%)
97
M.P (°C) [Lit.]
[59–62]
10
272–274
O
N
N
CN
NH2
O
6a
CH3
2
4-CH3
15
90
256–258
O
N
N
CN
NH2
O
6b
OCH3
3
4
4-OCH3
2,4-Cl2
15
10
92
98
240–242
246–248
O
N
CN
N
NH2
O
6c
Cl
Cl
O
N
CN
N
NH2
O
6d
NO2
5
4-NO2
10
95
256–258
O
N
CN
N
NH2
O
6e
N
6
7
4-C5H4N
15
10
96
96
260–262
270–272
O
N
CN
N
NH2
O
6f
Cl
4-Cl
O
N
CN
N
NH2
O
6g
Conditions: aldehyde (1 mmol), malononitrile (1 mmol), phthalhydrazide (1 mmol), catalyst (30 mg),
80 °C, aIsolated pure yield
1 3

Synthesis of Fe3O4‑supported Schif base Cu (II) complex:…
Fig. 7 a The XRD of reused catalyst, b the FT-IR reused catalyst, c the EDX of reused catalyst and d
Recyclability of the catalyst in synthesis of 4a (I), 6a (II) under the optimized conditions
Proposed reaction mechanism
A plausible mechanism for synthesis of 5‑oxo‑dihydropyrano[3,2‑c]chromene,
2‑amino‑3‑ cyano‑1,4,5,6‑tetrahydropyrano[3,2‑c] quinolin‑5‑one derivatives
Scheme
4 shows a plausible mechanism for the synthesis of 5-oxo-
dihydropyrano[3,2-c]chromene, 2-amino-3-cyano-1,4,5,6-tetrahydropyrano[3,2-c]
quinolin-5-one derivatives catalyzed by Fe3O4@SiO2@ CPTES@Cu (II) Schif base
complex NPs. In frst, the aromatic aldehyde is activated by the nano-catalyst. So
that, activated aldehyde reacts with malononitrile via a Knoevenagel condensation
reaction and products the intermediate (1). Next, 4-hydroxycoumarin/4-hydroxyqui-
nolin-2(1H)-one adds to the intermediate (1) to generate the Michael adduct (2) by
the nano-catalyst. Finally, enolization of (II) occurs to yield the intermediate (3)
which undergoes intramolecular nucleophilic cyclization to provide highly respec-
tive products 4(a-k) [53].
1 3

H. Ebrahimiasl et al.
Scheme 4 Proposed mechanism for Fe3O4@SiO2@CPTES@Cu (II) Schif base complex catalyzed syn-
thesis of 5-oxo-dihydropyrano[3,2-c]chromene-2-amino-3-cyano-1,4,5,6-tetrahydropyrano- [3,2-c]quino-
lin-5-one derivatives
Plausible mechanism for synthesis of 1H‑pyrazolo[1,2‑b]phthalazine‑5,10‑dione
derivatives
Based on a literature survey [60], a similar plausible mechanism synthesis of
1H-pyrazolo[1,2-b]phthalazine-5,10-dione derivatives 6(a-g) is shown in Scheme 5.
The frst step involves the formation of ylidenemalononitrile via the condensation
of aromatic aldehydes with malononitrile under the catalytic efect of the nano-
catalyst (Intermediate 1), Then, Michael addition between intermediate (1) and
1 3

Synthesis of Fe3O4‑supported Schif base Cu (II) complex:…
Scheme 5 Proposed mechanism for Fe3O4@SiO2@CPTES@Cu(II) Schif base complex catalyzed syn-
thesis of 1H-pyrazolo[1,2-b]phthalazine-5,10-dione derivatives
phthalhydrazide, followed by intramolecular cyclization, is assisted the nano-cata-
lyst to furnish the desired pure products.
Conclusion
In summary, we designed and synthesized a copper/Schif base complex immobi-
lized on silica MNPs as a novel nanomagnetic catalyst and characterized by diverse
analytical techniques. This nanoparticle has been introduced as an efcient and green
protocol for the one-pot synthesis of dihydropyrano[3,2-c]chromen-2-one, 2-amino-
3-cyano-1,4,5,6-tetrahyropyrano[3,2-c]quinolin-5-one and 1H-pyrazolo[1,2-b]
phthalazine-5,10-dione derivatives. The main advantages of this catalytic method
are high yields of products, short reaction times, high surface area, thermal stability,
1 3

H. Ebrahimiasl et al.
the use of an inexpensive copper metal and the simple of separation without the
need for column chromatographic, recovery, reuse and eco-friendliness of the nano-
catalyst. Besides, the catalyst is reusable and shows efciency up to 6 cycles with-
out signifcant loss of the catalytic activity or metal loading. We anticipate from the
strategy in our work can provide an attractive catalytic system large-scale degrada-
tion of organic pollutants and other industrially signifcant products.
Acknowledgements The authors wish to thank the Research Council of Bu‐Ali Sina University for fnan-
cial support to carry out this research.
Compliance with ethical standards
Conficts of interest We have no conficts of interest to disclose.
References
1. S. Chandra, L.K. Gupta, S. Agrawal, Trans. Met. Chem. 32, 240 (2007)
2. A.I. Hanafy, A.B.K.T. Maki, M.M. Mostafa, Trans. Met. Chem. 32, 960 (2007)
3. S. Chandra, A. Gautum, M. Tyagi, Trans. Met. Chem. 32, 1079 (2007)
4. L.T. Bozic, E. Marotta, P. Traldi, Polyhedron 26, 1663 (2007)
5. H. Keypour, M. Shayesteh, M. Rezaeivala, F. Chalabian, Y. Elerman, O. Buyukgungor, J. Mol. Str.
1032, 62 (2013)
6. S. Ilhan, H. Temel, Trans. Met. Chem. 32, 1039 (2007)
7. M.C. Fernandez, R. Basitida, A. Macias, L. Valencia, P.P. Lourida, Polyhedron 25, 783 (2006)
8. S. Mahmoudi-GomYek, D. Azarifar, M. Ghaemi, H. Keypour, M. Mahmoudabadi, Appl. Organo-
metal. Chem. 33, e4918 (2019)
9. X. Wu, C. Lu, Z. Zhou, G. Yuan, R. Xiong, X. Zhang, Environ. Sci. NANO 1, 71 (2014)
10. H. Ebrahimiasl, D, Azarifar, Appl. Organometal. Chem. 34, e5359 (2020)
11. L. Ma’mani, M. Sheykhan, A. Heydari, M. Faraji, Y. Yamini, Appl. Catal. A 250, 64 (2010)
12. J. Deng, L.P. Mo, F.Y. Zhao, L.L. Hou, L. Yang, Z.H. Zhang, Green Chem. 254, 2576 (2011)
13. A. Saxena, A. Kumar, S. Mozumdar, J. Mol. Catal. A: Chem. 269, 35 (2007)
14. C. Yuan, Z. Huang, J. Chen, Catal. Commun. 24, 56 (2012)
15. Z. Cimerman, S. Miljanić, N. Galić, Croat. Chem. Acta 73, 81 (2000)
16. D.N. Dhar, C.L. Taploo, J. Sci. Indust. Res. 41, 501 (1982)
17. B.S. Sathe, E. Jaychandran, V.A. Jagtap, G.M. Sreenivasa, Inter. J. Pharm. Res. Dev. 3, 164 (2011)
18. A. Pandey, D. Dewangan, S. Verma, A. Mishra, R.D. Dubey, Inter. J. ChemTech Res. 3, 178 (2011)
19. C. Chandramouli, M.R. Shivanand, T.B. Nayanbhai, B. Bheemachari, R.H. Udupi, J. Chem. Pharm.
Res. 4, 1151 (2012)
20. S. Li, S. Chen, S. Lei, H. Ma, R. Yu, D. Liu, Corros. Sci. 41, 1273 (1999)
21. P. Venkatesh, Asian J. Pharm. Health Sci. 1, 8 (2011)
22. A.K. Chaubey, S.N. Pandeya, Inter. J. ChemTech Res. 4, 590 (2012)
23. K. Mounika, B. Anupama, J. Pragathi, C. Gyanakumari, J. Sci. Res. 2, 513 (2010)
24. R. Miri, N. Razzaghi-asl, M. K. Mohammadi, J. Mol. Model., 19, 727 (2013).
25. D. Wei, N. Li, G. Lu, K. Yao, Sci. China B 49, 225 (2006)
26. G. Avaji, C. H. Vinod Kumar, S. A. Patil, K. N. Shivananda, Eur. J. Med. Chem., 44, 3552 (2009).
27. T. Aboul-Fadl, F.A. Mohammed, E.A. Hassan, Arch. Pharm. Res. 26, 778 (2003)
28. S. Chandra, M. Pundir, Spectrochim. Acta A 69, 1 (2008)
29. S. Chandra, R. Gupta, N. Gupta, S.S. Bawa, Trans. Met. Chem. 31, 147 (2006)
30. S. Chandra, L.K. Gupta, S. Agrawal, Trans. Met. Chem. 32, 558 (2007)
31. G. Cerchiaro, A.M.C. Ferreira, J. Braz. Chem. Soc. 17, 1473 (2006)
32. M. B. Gawande, A. Goswami, F.-X. Felpin, T. Asefa, X. Huang, R. Silva, X. Zou, R. Zboril, R. S.
Varma, Chem. Rev., 116, 6, 3722 (2016).
33. D. Das, Chem. Select., 1, 9, 1959 (2016).
1 3

Synthesis of Fe3O4‑supported Schif base Cu (II) complex:…
34. I. Bertini-H.B. Gray-S.J. Lippard-J.S. Valentine, Bioinorganic chemistry, University Science Books,
1994.
35. M. Norouzi, A. Ghorbani-Choghamarani, M. Nikoorazm, RSC Adv. 6, 92387 (2016)
36. H. Keypour, M. Rezaeivala, L. Valencia, P. Pérez-Lourido, H.R. Khavasi, Polyhedron 28, 3755
(2009)
37. N. Raman, Y. P. Raja, A. Kulandaisamy, J. Chem. Sci., 11, 183 (2001).
38. S. Sobhani, F. Khakzad, Appl. Organome. Chem. 31, e3877 (2017)
39. A. Ghorbani-Choghamarani, B. Tahmasbi, P. Moradi, N. Havasi, Appl. Organome. Chem. 30, 619
(2016)
40. M. Hajjami, S. Kolivand, Appl. Organome. Chem. 30, 282 (2016)
41. R. Zahedi, Z. Asadi, F.D. Firuzabadi, A Highly Active, Cat. Lett., 1 (2019).
42. J. Zhu-H. Bienaymé, Multicomponent reactions, Wiley, New York, 2006.
43. H. Bienaymé, C. Hulme, G. Oddon, P. Schmitt, Chem-Eur. J. 6, 3321 (2000)
44. R.V. Orru, E. Ruijter, Synthesis of heterocycles via multicomponent reactions II, Springer Science &
Business Media, Heidelberg, 2010.
45. M. Khaleghi-Abbasabadi, D. Azarifar, Res. Chem. Intermed. 45, 2095 (2019)
46. D. Azarifar, O. Badalkhani, Y. Abbasi, M. Hasanabadi, J. Iran. Chem. Soc. 14, 403 (2017)
47. M. Piltan, Heterocyclic Commun. 2, 401 (2017)
48. M.-J. Yao, Z. H. Guan, Y. He, Synth. Commun. 43, 2073 (2013)
49. H. Keypour, M. Aidi, M. Mahmoudabadi, R. Karamian, M. Asadbegy, R.W. Gable, J. Mol. Struct.
1198, 126666 (2019)
50. M. Ma, Y. Zhang, X. Li, D. Fu, H. Zhang, N. Gu, Colloids Surf. A. Physicochem. Eng. Asp. 224,
207 (2003)
51. M. Tajbakhsh, M. Farhang, R. Hosseinzadeh, Y. Sarraf, RSC Adv. 4, 23116 (2014)
52. D. Azarifar, H. Ebrahimiasl, R. Karamian, M. Ahmadi-Khoei, J. Iran. Chem. Soc. 16, 341 (2019)
53. K. Tabatabaeian, H. Heidari, M. Mamaghani, N.O. Mahmoodi, Appl. Organomet. Chem. 26, 56
(2012)
54. M. Khoobi, L. Ma’mani, F. Rezazadehb, Z. Zareieb, A. Foroumadia, A. Ramazanib, J. Mol. Catal.
A Chem, 359, 74 (2012).
55. D. Azarifar, O. Badalkhani, Y. Abbasi, M. Hasanabadi, J. Iran. Chem. Soc. 14, 403 (2017)
56. K. Niknam, A. Piran, Curr. Opin. Green Sustain. Chem. 3, 1 (2013)
57. E. Abbaspour-Gilandeh, M. Aghaei-Hashjinb, A. Yahyazadeh, H. Salemi, RSC Adv. 6, 55444
(2016)
58. M. Lei, L. Ma, L.H. Hu, Tetrahedron Lett. 52, 2597 (2011)
59. R. Ghahremanzadeh, Gh Imani Shakibaei, A. Bazgir, Synlett, 1129 (2008).
60. M.R. Nabid, S.J. Tabatabaei Rezaei, R. Ghahremanzadeh, A. Bazgir, Ultrason. Sonochem., 17, 159
(2010).
61. A. Vafaee, A. Davoodnia, M. Pordel, M.R. Bozorgmehr, Orient. J. Chem. 31, 2153 (2015)
62. A. Mulika, M. Deshmukha, D. Chandama, P. Patilb, S. Jagdalea, D. Patila, S. Sankpal, Der Pharma.
Chem. 5, 19 (2013)
Publisher’s Note Springer Nature remains neutral with regard to jurisdictional claims in published
maps and institutional afliations.
1 3