Excellent alkene epoxidation catalytic activity of macrocyclic-based complex of dioxo-Mo(VI) on supermagnetic separable nanocatalyst

Received: 2 May 2017

DOI: 10.1002/aoc.3986

Revised: 17 June 2017

Accepted: 21 June 2017

F U L L P A P E R

Excellent alkene epoxidation catalytic activity of

macrocyclic‐based complex of dioxo‐Mo(VI) on

supermagnetic separable nanocatalyst

Fatemeh Payami | Abolfazl Bezaatpour

| Habibollah Eskandari

Department of Chemistry, Faculty of Basic

A phenoxybutane‐based Schiff base complex of cis‐dioxo‐Mo(VI) was sup-

ported on paramagnetic nanoparticles and characterized using powder X‐

ray diffraction, infrared, diffuse reflectance and atomic absorption spectros-

copies, scanning and transmission electron microscopies and vibrating sam-

ple magnetometry. The separable nanocatalyst was tested for the selective

epoxidation of cyclohexene, cyclooctene, styrene, indene, α‐pinene, 1‐octene,

1‐heptene, 1‐dodecene and trans‐stilbene using tert‐butyl hydroperoxide

(80% in di‐tert‐butyl peroxide–water, 3:2) as oxidant in chloroform. The cat-

alyst was efficient for oxidation of cyclooctene with 100% selectivity for

epoxidation with 98% conversion in 10 min. We were able to separate mag-

netically the nanocatalyst using an external magnetic field and used the cat-

alyst at least six successive times without significant decrease in conversion.

The turnover frequency of the catalyst was remarkable (2556 h⁻¹for

cyclooctene). The proposed nanomagnetic catalyst has advantages in terms

of catalytic activity, selectivity, catalytic reaction time and reusability by

easy separation.

Science, University of Mohaghegh,

Ardabili 179, Ardabil, Iran

Correspondence

Abolfazl Bezaatpour, Department of

Chemistry, Faculty of Basic Science,

University of Mohaghegh Ardabili 179,

Ardabil, Iran.

Email: bezaatpour@uma.ac.ir

Funding information

University of Mohaghegh Ardabili, Grant/

Award Number: 4562; Research Council of

Mohaghegh‐e‐Ardabili University

KEYWORDS

epoxidation, macrocyclic, molybdenum, nanocatalyst, Schiff base

1 | INTRODUCTION

and causes additional waste. Furthermore, insufficient

chemical and thermal stability, leaching of active metal

Over the past two decades, production of epoxides from

olefins has given beneficial starting chemical materials

for access to industrially valuable products such as drugs,

epoxy resins, intermediates and surfactants.^[1–3]

Molybdenum(VI) Schiff base complexes have significant

advantages such as stability, economy, commercial avail-

ability and environmental friendliness in epoxidation of

olefins compounds.^[4–7]tert‐Butyl hydroperoxide (TBHP)

is an environmentally friendly organic peroxide widely

used in a variety of epoxidation processes with good ther-

mal stability.^[8–11]The recovery of a homogeneous catalyst

from a reaction mixture is often difficult with high costs

into solvent and recycling of catalyst remain scientific

challenges.^[12,13]These problems may be solved by

replacement of homogeneous oxidation catalysts by

environmentally friendly heterogeneous catalysts.^[14]

Therefore, supporting of metal complexes has been the

subject of a lot of research in catalytic fields.^[15–18]A main

idea for supporting of metal complexes is to anchor the

metal complexes onto large‐surface‐area inorganic mate-

rials such as zeolites and metal oxides.^[16,19–25]

Nowadays, magnetite nanoparticles are of particular

interest because of their unique properties including high

surface area, low toxicity, ability to be separated and

Appl Organometal Chem. 2017;e3986.

wileyonlinelibrary.com/journal/aoc

1 of 10

https://doi.org/10.1002/aoc.3986

2 of 10

PAYAMI ET AL.

biocompatibility.^[16,26–30]Magnetic separation renders the

recycling of catalysts from solution using external mag-

netic fields much easier than filtration and centrifugation.

In continuation of our previous investigation of

catalytic activity of Schiff base complexes,^{[6,9–11,15,19]}

herein we report the anchoring of novel cis‐

dioxomolybdenum(VI) macrocyclic Schiff base complex

by reaction of 1,4‐bis(2‐carboxyaldehydephenoxy)butane,

α‐pinene, indene, trans‐stilbene) and terminal alkenes (1‐

heptene, 1‐octene, 1‐dodecene, styrene) with TBHP (80%

in di‐tert‐butyl peroxide–water, 3:2) as oxidant. The reus-

ability of Fe₃O₄@SiO₂‐(CH₂)₃‐PBSB/MoO₂was also stud-

ied in the epoxidation of cyclooctene with TBHP in

chloroform for six successive reactions.

2 | EXPERIMENTAL

MoO₂Cl₂(DMF)₂

and

amino‐modified

magnetite

nanoparticles (Scheme 1). The new nanocatalyst

(Fe₃O₄@SiO₂‐(CH₂)₃‐PBSB/MoO₂) was characterized

using Fourier transform infrared (FT‐IR) spectroscopy,

scanning electron microscopy (SEM), transmission

electron microscopy (TEM), diffuse reflectance

spectroscopy (DRS), vibrating sample magnetometry

(VSM), energy‐dispersive X‐ray spectroscopy (EDX) and

powder X‐ray diffraction (XRD), and tested for

epoxidation of internal alkenes (cyclohexene, cyclooctene,

2.1 | Materials and instrumentation

1,4‐Dibromobutane,

2‐hydroxybenzaldehyde,

N,N′‐

dimethylformamide, styrene, cyclohexene, α‐pinene,

cyclooctene, indene, 1‐dodecene, 1‐heptene, 1‐octene,

trans‐stilbene, ferrous chloride, ferric chloride, 3‐

aminopropyltrimethoxysilane(APTMS) and ammonia

(25% w/w) were purchased from Merck Chemical

1

Company. NMR spectra were recorded using a Bruker

SCHEME 1 Preparation of heterogeneous nanocatalyst: (i) tetraethoxysilane/EtOH, (ii) 3‐aminopropyltrimethoxysilane/EtOH, (iii)

K₂CO₃/DMF, (iv) stirring at 70 °C for 48 h/EtOH, (v) MoO₂Cl₂(DMF)₂/EtOH

PAYAMI ET AL.

3 of 10

NMR 400 (400 MHz) spectrophotometer in CDCl₃solvent.

CHNS analyses were performed using an elemental

analyser (CHNSO‐A PE 2400 series II system). Atomic

absorption analysis was carried out with an Analytik Jena

spectrometer. Analysis of oxidation products was

determined by GC using an Agilent 7890 A with a capil-

lary column and flame ionization detector. Column

temperature was programmed between 180 and 200°C at

a rate of 2°C min⁻¹. Nitrogen was used as carrier gas at

20 ml min⁻¹. FT‐IR spectra were obtained with a Fourier

transform infrared spectrometer using KBr pellets over

the range 400–4000 cm⁻¹. VSM was conducted with an

MDKF‐FORC/VSM) Megnatis‐Daghigh‐Kashan Co.).

DRS data were recorded with a Scinco 4100 in the range

200–900 nm using barium sulfate as reference. Powder

small‐angle XRD studies were done with a Philips X⁰Pert

with Cu Kα radiation (k = 1.54 Å). Surface morphology

and distribution of nanoparticles were investigated via

SEM with a LEO 1430 VP instrument.

2.2 | Preparation of Fe₃O₄@SiO₂‐

(CH₂)₃NH₂

Fe₃O₄nanoparticles and Fe₃O₄@SiO₂were prepared

using the chemical co‐precipitation method reported in

the literature.^[13,31,32]To a mixture of Fe₃O₄@SiO₂

(0.5 g) in ethanol (50 ml) was added dropwise APTES

(2.5 ml) dissolved in 50 ml of ethanol. After 12 h stirring

of the mixture at 70 °C, the aminated magnetic

nanoparticles were collected with an external magnetic

field and washed with water three times. FT‐IR (KBr,

cm⁻¹): 3406 [ν(O―H)], 2924 [ν(C―H) aliphatic], 998

[ν(Si―O)], 610 [ν(Fe―O)].

2.3 | Synthesis of 1,4‐Bis(2‐

carboxyaldehydephenoxy)butane

1,4‐Bis(2‐carboxyaldehydephenoxy)butane was synthe-

sized via

a

previously reported method.^[33]1,4‐

Dibromobutane (1.08 g, 5 mmol) was dissolved in 5 ml

of dimethylformamide which was added dropwise to a

solution of 2‐hydroxybenzaldehyde (1.22 g, 10 mmol)

and potassium carbonate (0.691 g, 5.0 mmol) in

dimethylformamide (30 ml). The mixture was refluxed

for 15 h and then cooled to room temperature. Then,

distilled water (70 ml) was added to the mixture and

was kept at 0–4°C for2 h. The creamy precipitated solids

were filtered and washed with water and dried in air.

The powder was crystallized from ethanol for

characterization. Yield 1.19 g (80%); m.p. 108°C. Anal.

Calcd for C₁₈H₁₈O₄(%): C, 72.47; H, 6.08. Found (%): C,

72.1; H, 6.50. FT‐IR (KBr, cm⁻¹): 1678 [ν(C―O)], 2956,

1

2862 [ν(aliphatic C―H)]. H NMR (400 MHz, CDCl₃, δ,

ppm): 10.52 (s, 2H, CH―O), 7–7.80 (m, 8H, aromatic),

4.2 (t, 4H, aliphatic O―CH₂―C), 2.1 (t, 4H, C―CH₂―C)

(supporting information, Figure S1).

FIGURE

1

FT‐IR spectra of (a) Fe₃O₄nanoparticles, (b)

Fe₃O₄@SiO₂‐(CH₂)₃‐NH₂, (c) Fe₃O₄@SiO₂‐(CH₂)₃‐PBSB and (d)

Fe₃O₄@SiO₂‐(CH₂)₃‐PBSB/MoO₂

FIGURE 2 XRD patterns of (a)

magnetite nanoparticles, (b) Fe₃O₄@SiO₂‐

(CH₂)₃‐NH₂and (c) Fe₃O₄@SiO₂‐(CH₂)₃‐

PBSB/MoO₂

4 of 10

PAYAMI ET AL.

PBSB was separated using an external magnet and

washed with water and ethanol several times. FT‐IR

(KBr, cm⁻¹): 623 [ν(Fe―O)], 994 [ν(Si―O)], 1636

[ν(imine C―N)], 2925, 2849 [ν(aliphatic C―H)], 3418

[ν(O―H)].

2.4 | Preparation of Fe₃O₄@SiO₂‐(CH₂)₃‐

PBSB

A solution of 1,4‐bis(2‐carboxyaldehydephenoxy)butane

(1.49 g, 5 mol, in 60 ml of ethanol) was added to a suspen-

sion of Fe₃O₄@SiO₂‐(CH₂)₃NH₂(1.0 g in 60 ml of etha-

nol). The reaction mixture was refluxed with stirring for

2 days. After cooling the mixture, Fe₃O₄@SiO₂(CH₂)₃‐

2.5 | Preparation of Fe₃O₄@SiO₂‐(CH₂)₃‐

PBSB/MoO₂

An amount of 345.2 g (1 mmol) of MoO₂Cl₂(DMF)₂

(prepared by the method in the literature^[34]) dissolved

in 40 ml of dichloromethane was added dropwise to a

suspension of 1 g of Fe₃O₄@SiO₂‐(CH₂)₃‐PBSB in 40 ml

of methanol and the mixture was refluxed for 24 h. Then,

the solid was separated using an external magnetic field

and washed several times with water and ethanol for

removal of unreacted MoO₂Cl₂(DMF)₂and dried in

40 °C. FT‐IR (KBr, cm⁻¹): 588 [ν(Fe―O)], 916, 946

[ν(cis, O―Mo―O)], 1024 [ν(Si―O―Si)], 1652 [ν(C―N)],

2938, 2860 [aliphatic C―H], 3410 [ν(O―H)].

2.6 | Investigation of catalytic activity

Investigation of the catalytic activity of heterogeneous

Fe₃O₄@SiO₂‐(CH₂)₃‐PBSB/MoO₂was carried out using

the epoxidation of various internal and terminal olefins.

For determination of epoxidation catalytic activity,

0.05 g of Fe₃O₄@SiO₂‐(CH₂)₃‐PBSB/MoO₂was sonicated

FIGURE

3

Magnetization response of (a) magnetite

nanoparticles and (b) Fe₃O₄@SiO₂‐(CH₂)₃‐PBSB/MoO₂at 25°C

FIGURE 4 SEM images of (a) magnetite nanoparticles and (b) Fe₃O₄@SiO₂‐(CH₂)₃‐PBSB/MoO₂. TEM images of (c) Fe₃O₄@SiO₂‐(CH₂)₃‐

PBSB/MoO₂

PAYAMI ET AL.

5 of 10

in 5 ml of chloroform as solvent for 20 min. Then

the olefins (10 mmol) and TBHP (15 mmol) were

added with a ratio of 2:3 to the catalyst reactor.

The catalytic system was refluxed with stirring for

15 min and the catalyst was removed using an

external magnetic field. The oxidation products were

monitored using GC.

shifted to 1652 cm⁻¹after coordination with Mo⁶⁺cen-

tre.^[35]So, the appearance of two adjacent bands at 916

and 946 cm⁻¹was characteristic of the presence of

MoO₂group (Figure 1d).^[36]The bands at 2938 and

2860 cm⁻¹can be assigned to the aliphatic group (CH₂)

of APTMS. The FT‐IR spectral data confirm the

supporting of the Schiff base Mo(VI) complex on the mag-

netic nanoparticles.

Figure 2 shows the powder XRD patterns of Fe₃O₄

nanoparticles,Fe₃O₄@SiO₂‐(CH₂)₃NH₂and Fe₃O₄@SiO₂‐

(CH₂)₃‐PBSB/MoO₂. Comparing the three patterns and

that of standard Fe₃O₄nanoparticles (reference JCPDS

card no. 87–2334), we observed (220, 2θ = 30.13°), (331,

2θ = 35.65°), (400, 2θ = 43.51°), (422, 2θ = 54.25°), (511,

2θ = 57.19°) and (440, 2θ = 63.13°) diffraction peaks for

Fe₃O₄nanoparticles, Fe₃O₄@SiO₂‐(CH₂)₃NH₂and

Fe₃O₄@SiO₂‐(CH₂)₃‐PBSB/MoO₂. The observed broad

3 | RESULTS AND DISCUSSION

3.1 | Synthesis and characterization

Heterogeneous Fe₃O₄@SiO₂‐(CH₂)₃‐PBSB/MoO₂catalyst

was prepared according to the reaction of 1,4‐bis(2‐

carboxyaldehydephenoxy)butane, MoO₂Cl₂(DMF)₂and

amino‐modified Fe₃O₄@SiO₂nanoparticles. Figure 1

shows the FT‐IR spectra of Fe₃O₄nanoparticles,

Fe₃O₄@SiO₂‐(CH₂)₃NH₂, supporting Schiff base ligand

and Fe₃O₄@SiO₂‐(CH₂)₃‐PBSB/MoO₂. Fe―O and Si―O

stretching bands appeared at 610 and 998 cm⁻¹. As shown

in Figure 1(c,d), the band assigned to C―N stretching

vibration of supporting Schiff base ligand at 1636 cm⁻¹

peak

(2θ

=

22–29°)

of

Fe₃O₄@SiO₂‐

(CH₂)₃NH₂andFe₃O₄@SiO₂‐(CH₂)₃‐PBSB/MoO₂

indi-

cated the existence of amorphous silicon dioxide.

Figure

3

shows the magnetization curves of

synthesized Fe₃O₄nanoparticles and Fe₃O₄@SiO₂‐

FIGURE 5 EDX spectrum of

Fe₃O₄@SiO₂‐(CH₂)₃‐PBSB/MoO₂

SCHEME 2 Proposed mechanism for

catalytic oxidation of cyclooctene

6 of 10

PAYAMI ET AL.

(CH₂)₃‐PBSB/MoO₂. The magnetization curves show no

hysteresis loop and have magnetic saturation at 57.67

and 13.63 emu g⁻¹, respectively. It seems that the silica

layer on the magnetite nanoparticles in Fe₃O₄@SiO₂‐

(CH₂)₃‐PBSB/MoO₂is the main cause of reduced

magnetic saturation. Anyway, the result shows that the

catalyst can be separated from solution using an external

magnetic field.

Figure 4(a,b) shows SEM images of Fe₃O₄

nanoparticles and Fe₃O₄@SiO₂‐(CH₂)₃‐PBSB/MoO₂.

Comparison of the SEM images shows no change in

morphology. Figure 4(c) shows TEM images of

Fe₃O₄@SiO₂‐(CH₂)₃‐PBSB/MoO₂nanocatalyst. The TEM

images of the nanocatalyst show the particle size to be

approximately 15–18 nm. As presented in Figure 5, the

EDX spectrum of Fe₃O₄@SiO₂‐(CH₂)₃‐PBSB/MoO₂

indicates the presence of Mo, Si, C, Cl and other elements

on the catalyst surface.

terminal alkenes (1‐heptene, 1‐octene, 1‐dodecene, sty-

rene) using TBHP. At the beginning of the epoxidation

catalytic process, solvent, amount of catalyst, temperature

of catalytic reactor, reaction time and parameters such as

the kind of oxidant and molar ratio of oxidant to substrate

were optimized. After running the catalytic process for

epoxidation of cyclooctene with TBHP and various sol-

vents, it was found that chloroform was a suitable solvent

among dichloromethane, toluene, acetonitrile, chloro-

form, methanol and 1,2‐dichloroethane with highest con-

version (98%) during 10 min. By considering of

mechanism in Scheme 2, it seems that the competition

between methanol and acetonitrile as a coordinator sol-

vent and (CH₃)₃COO⁻in coordination to Mo(VI) causes

a marked decrease in the catalyst activity.^[37]Apparently,

the lower reflux reaction temperature is the reason for the

lowest epoxidation conversion in CH₂Cl₂(37%). For opti-

mization of reaction temperature, catalytic epoxidation of

cyclooctene was carried out in chloroform with TBHP at

four temperatures (30, 40, 50, 60°C). As evident from

Table 1, the best results were obtained at 60°C. For

selecting a suitable oxidant, hydrogen peroxide–urea,

sodium periodate, hydrogen peroxide and TBHP were

tested in cyclooctene epoxidation in chloroform. As evi-

dent from Table 1, we obtained the best results in the

3.2 | Epoxidation of olefins catalysed by

Fe₃O₄@SiO₂‐(CH₂)₃‐PBSB/MoO₂

The Fe₃O₄@SiO₂‐(CH₂)₃‐PBSB/MoO₂catalyst was tested

for selective oxidation of internal alkenes (cyclohexene,

cyclooctene, α‐pinene, indene, trans‐stilbene) and

a

TABLE 1 Optimization of solvent, oxidant and temperature in epoxidation of cyclooctene catalysed by Fe₃O₄@SiO₂‐(CH₂)₃‐PBSB/MoO₂

Solvent

Catalyst

[ox]/[sub]

Oxidant

Temp. (°C)

Conversion (%)

Chloroform

Fe₃O₄@SiO₂‐(CH₂)₃‐PBSB/MoO₂

3/2

TBHP

30

17

Chloroform

1,2‐Dichloroethane

Acetonitrile

Toluene

Fe₃O₄@SiO₂‐(CH₂)₃‐PBSB/MoO₂

3/2

1/2

1/1

2/1^b

5/1^b

3/2

TBHP

UHP

40

30

67

100

70

95

100

76

2

50

60

70

79

6

Dichloromethane

Methanol

Reflux

60

Chloroform

60

0

NaIO₄

H₂O₂

60

0

60

0

c

MoO₂(DMF)₂Cl₂

TBHP

60

76

^aReaction condition: solvent = 5 ml; catalyst = 0.05 g; 10 mmol alkene and 20 mmol oxidant.

^b100% conversion obtained in 15 min.

^cComplex amount used was 2.4 × 10⁻⁵mol).

PAYAMI ET AL.

7 of 10

a

TABLE 2 Results of catalytic epoxidation of various alkenes with TBHP catalysed by Fe₃O₄@SiO₂‐(CH₂)₃‐PBSB/MoO₂

Amount of

catalyst (g)^b

Conversion, %

(reaction time)

Selectivity

of epoxy (%)

Alkene

Main product

0.00

16 (15 min)

100

0.02

0.03

0.04

0.05

90 (15 min)

93 (15 min)

94 (15 min)

100

98 (10 min)

100(15 min)

100

0.05

100 (20 min)

100

0.05

44 (120 min)

30 (60 min)

41

49

0.05

27 (60 min)

45 (180 min)

86

42

0.05

86 (180 min)

87 (180 min)

100

^aCatalytic reaction conditions: chloroform (5 ml), 10 mmol alkene and 15 mmol TBHP.

^bAmount of catalyst loaded on nanoparticles is 4.6% (calculated by EDX and atomic absorption spectroscopy).

presence of TBHP. This oxidant has some significant

advantageous: (1) high selectivity; (2) unreactive towards

substrate without catalyst; (3) high thermal stability; (4)

environmentally friendly. The epoxidation of cyclooctene

was carried out using various of [TBHP]/[cyclooctene]

ratios. For this, we used ratios of 0.5, 1, 1.5, 2 and 5 in sep-

arate catalytic reactions. As summarized in Table 1, an

increase in catalytic activity was proportional to increas-

ing [TBHP]/[cyclooctene] ratio and we obtained the

maximum conversion at a ratio of 1.5. The amount of cat-

alyst was optimized for epoxidation of cyclooctene by

using 0.000, 0.020, 0.030, 0.040 and 0.050

g of

Fe₃O₄@SiO₂‐(CH₂)₃‐PBSB/MoO₂. As presented in

Table 2, the conversion increases with increasing catalyst

amount. Finally, we selected chloroform (5 ml) as solvent,

FIGURE 6 Recycling of catalyst for several runs. Reaction

conditions: Chloroform (5 ml), cyclooctene (10 mmol), TBHP

(15 mmol), 10 min, 60°C

FIGURE 7 FT‐IR spectra of Fe₃O₄@SiO₂‐(CH₂)₃‐PBSB/MoO₂

before catalytic reaction (solid) and after sixth run (dashed)

8 of 10

PAYAMI ET AL.

catalytic oxidation of substrate with TBHP in the blank

run (without catalyst) occurs with 24% conversion. The

chemical and physical stability of catalyst allows its

recycling and reuse several (six) times (Figure 6). The

catalyst was separated easily with a magnet and used

several times for subsequent epoxidation reactions. As

shown in Figure 7, there are no changes in the FT‐

IR spectra for the catalyst before oxidation and after

the sixth run. Also, a comparison between DRS spectra

of the catalyst before and after epoxidation process

shows no change (Figure 8). Considering the conver-

sion results, solvent optimization and the literature,^[38]

it seems that the proposed mechanism proceeds via a

seven‐coordinate intermediate (Scheme 2). In respect

to the mechanism in Scheme 2, it may the competition

between methanol, acetonitrile as a coordinator solvent

and (CH₃)₃COO⁻in coordination to Mo(VI) in step

(II) that causes a marked decrease in the catalyst

activity.^[37]

FIGURE 8 DRS spectra of Fe₃O₄@SiO₂‐(CH₂)₃‐PBSB/MoO₂

before catalytic process (solid) and after sixth run (dashed)

olefin (10 mmol) as substrate, TBHP (15 mmol) as oxidant

and 0.05 g of catalyst (2.4 × 10⁻⁵mol loading of catalyst

calculated by atomic absorption) at 60°C. By monitoring

of the catalytic reactor, the final solution exhibited no col-

our and no significant Mo leaching (detected by atomic

absorption) in the solution after the catalytic procedure.

The results of catalytic epoxidation of olefins are summa-

rized in Table 2. The catalytic investigation demonstrates

98% conversion and 100% epoxidation selectivity for

cyclooctene in 10 min. So the turnover frequency of the

catalyst for cyclooctene epoxidation (3789 h⁻¹) is remark-

able. It seems that the tendency of internal alkenes for

epoxidation is more than that of terminal alkenes. The

Table 3 compares the present catalyst with those

previously reported in the literature. In this work, we

introduced a suitable magnetically separable catalytic

system for epoxidation of olefins. The novel presented

catalyst showed higher epoxidation catalytic activity for

cyclooctene epoxidation (100% conversion) than

previously reported ones (36%,^[39]34%^[42]and 86%^[41]).

Finally, comparing the catalytic reaction time and

conversion of reported works (1 day,^[39,42,44]12 h,^[17]

18 h,^[40]8 h,^[41,46,50]7 h,^[48]5 h,^[45]4 h^[43]) and

Fe₃O₄@SiO₂‐(CH₂)₃‐PBSB/MoO₂(10 min), it is evident

that the present catalyst is efficient, time saving and

paramount.

TABLE 3 Comparison of literature reports for epoxidation of cyclooctene under various conditions

Catalyst

Reaction conditions

Conversion (%)

Ref.

[39]

MoO₂–thio Schiff base

TBHP/CHCl₃/24 h

36

[40]

[41]

[17]

[42]

[43]

[44]

[45]

[46]

[47]

[48]

[49]

[50]

[MoO(O₂)₂(4‐MepyO)₂].H₂O

MoO₂(VI)T

UHP/C₄mim(PF₆)/18 h

TBHP/CH₃Cl/8 h

TBHP/C₂H₄Cl₂/12 h

TBHP/toluene/24 h

TBHP/CH₃Cl/4 h

TBHP/DCE/24 h

TBHP/CCl₄/5 h

90

86

[MoO₂(Salen) (piperazine)]_n

SM‐48ccg

95

34

Dioxo‐Mo(VI) acac‐AmpMCM‐41

[MoO₂Cl₂(oep‐H₂saldpen)]

Mag‐Mo‐Nano catalyst

Schiff base Mo(VI) catalysts

Polymer‐supported Mo

MoO₂Sal/APTSC MNPs

Mo‐APTS‐AC

97

100

99

TBHP/DCE/8 h

100

91

TBHP/CCl₄/3 h

TBHP/CH₃Cl/7 h

TBHP/CH₃Cl/3 h

TBHP/CH₃Cl/8 h

TBHP/CH₃Cl/10 min

99

89

MoO₂acacen@APTS NPs

Fe₃O₄@SiO₂‐(CH₂)₃‐PBSB/MoO₂

95

100

This work

PAYAMI ET AL.

9 of 10

[14] A. Mavrogiorgou, M. Baikousi, V. Costas, E. Mouzourakis, Y.

Deligiannakis, M. Karakassides, M. Louloudi, J. Mol. Catal. A

2016, 413, 40.

4 | CONCLUSIONS

In this work following our researches on catalytic activity,

we have reported the successful covalent anchoring of a

phenoxybutane‐based Mo(VI) tetradentate Schiff base

complex on magnetite nanoparticles. The novel paramag-

netic recoverable catalyst has been studied as

nanocatalyst for selective oxidation of alkenes. The cata-

lyst was recovered successfully using a magnet from the

catalytic reactor and reused as catalyst six times without

[15] A. Bezaatpour, M. Amiri, V. Jahed, J. Coord. Chem. 2011,

64, 1837.

[16] L. Hamidipour, F. Farzaneh, C. R. Chim. 2014, 17, 927.

[17] M. Bagherzadeh, M. Zare, J. Coord. Chem. 2013, 66, 2885.

[18] A. Bezaatpour, S. Khatami, K. Nejati, J. Iran. Chem. Soc. 2017,

https://doi.org/10.1007/s13738 ‐017 ‐1147 ‐4.

[19] A. Bezaatpour, M. Behzad, V. Jahed, M. Amiri, Y. Mansoori,

Z. Rajabalizadeh, S. Sarvi, React. Kinet. Mech. Catal. 2012,

107, 367.

a

decrease in conversion and selectivity. The

catalyst exhibited

Fe₃O₄@SiO₂‐(CH₂)₃‐PBSB/MoO₂

higher epoxidation catalytic activity^[39,40,51]and markedly

shorter catalytic reaction time^{[17,39,42–46,52,53]}than previ-

ously reported catalysts. The Fe₃O₄@SiO₂‐(CH₂)₃‐PBSB/

MoO₂catalyst shows a markedly high conversion in

10 min.

[20] A. M. Garcia, V. Moreno, S. X. Delgado, A. E. Ramírez, L. A.

Vargas, M. Á. Vicente, A. Gil, L. A. Galeano, J. Mol. Catal. A

2016, 416, 10.

[21] M. Fadhli, I. Khedher, J. M. Fraile, J. Mol. Catal. A 2016,

420, 282.

[22] S. P. Shylesh, M. Jia, A. Seifert, S. Adappa, S. Ernst, W. R. Thiel,

New J. Chem. 2009, 33, 717.

ACKNOWLEDGEMENT

[23] T. Chattopadhyay, A. Chakraborty, S. Dasgupta, A. Dutta, M. I.

Menéndez, E. Zangrando, Appl. Organometal. Chem. 2017, 31,

e3663.

We acknowledge the Research Council of Mohaghegh‐e‐

Ardabili University for the financial support and funding

of the project.

[24] P. Piaggio, P. McMorn, C. Langham, D. Bethell, P. C.

Bulman‐Page, F. E. Hancock, G. J. Hutchings, New J. Chem.

1998, 22, 1167.

ORCID

[25] Q. Tang, Y. Wang, J. Zhang, R. Qiao, X. Xie, Y. Wang, Y. Yang,

Appl. Organometal. Chem. 2016, 30, 435.

Abolfazl Bezaatpour http://orcid.org/0000-0001-5258-7796

[26] A. Farokhi, H. Hosseini‐Monfared, New J. Chem. 2016, 40, 5032.

[27] P. B. Bhat, B. R. Bhat, New J. Chem. 2015, 39, 273.

REFERENCES

[28] H. Eskandari, A. Bezaatpour, F. Eslami, J. Iran. Chem. Soc.

2017, 14, 457.

[1] O. A. Wong, Y. Shi, Chem. Rev. 2008, 108, 3958.

[2] M. L. Kuznetsov, J. C. Pessoa, Dalton Trans. 2009, 5460.

[29] C. I. Fernandes, M. D. Carvalho, L. P. Ferreira, C. D. Nunes, P.

[3] C. A. Gamelas, A. C. Gomes, S. M. Bruno, F. A. Almeida Paz, A.

A. Valente, M. Pillinger, C. C. Romão, I. S. Gonalves, Dalton

Trans. 2012, 41, 3474.

D. Vaz, J. Organometal. Chem. 2014, 760, 2.

[30] A. Ghorbani‐Choghamarani, M. Norouzi, J. Magn. Magn.

Mater. 2016, 401, 832.

[4] J. Zhang, P. Jiang, Y. Shen, W. Zhang, G. Bian, J. Porous, Mater.

2016, 23, 431.

[31] Z. Peng, K. Hidajat, M. Uddin, J. Colloid Interface Sci. 2004,

271, 277.

[5] G. Fioroni, F. Fringuelli, F. Pizzo, L. Vaccaro, Green Chem.

2003, 5, 425.

[32] X. Huang, W. Guo, G. Wang, M. Yang, Q. Wang, X. Zhang, Y.

Feng, Z. Shi, C. Li, Mater. Chem. Phys. 2012, 135, 985.

[6] A. Bezaatpour, S. Khatami, M. Amiri, RSC Adv. 2016, 6, 27452.

[33] S. Ilhan, H. Temel, A. Kilic, J. Coord. Chem. 2008, 61, 277.

[7] A. Bezaatpour, E. Askarizadeh, S. Akbarpour, M. Amiri, B.

[34] F. J. Arnaiz, R. Aguado, J. Sanz‐Aparicio, M. Martinez‐Ripoll,

Polyhedron 1994, 13, 2745.

Babaei, Mol. Catal. 2017, 436, 199.

[8] S. Akbarpour, A. Bezaatpour, E. Askarizadeh, M. Amiri, Appl.

Organometal. Chem. 2017, https://doi.org/10.1002/aoc.3804.

[35] W. Hill, N. Atabay, C. McAuliffe, F. McCullough, S. Razzoki,

Inorg. Chim. Acta 1979, 35, 35.

[9] J. Rahchamani, M. Behzad, A. Bezaatpour, V. Jahed, G.

[36] J. Topich, Inorg. Chem. 1981, 20, 3704.

Dutkiewicz, M. Kubicki, M. Salehi, Polyhedron 2011, 30, 2611.

[37] M. Bagherzadeh, M. Zare, V. Amani, A. Ellern, L. K. Woo, Poly-

hedron 2013, 53, 223.

[10] D. M. Boghaei, A. Bezaatpour, M. Behzad, J. Mol. Catal. A 2006,

245, 12.

[38] F. E. Kühn, M. Groarke, É. Bencze, E. Herdtweck, A. Prazeres,

A. M. Santos, M. J. Calhorda, C. C. Romão, I. S. Gonçalves, A.

D. Lopes, Chem. Eur. J. 2002, 8, 2370.

[11] A. Bezaatpour, React. Kinet. Mech. Catal. 2014, 112, 453.

[12] R. Dileep, B. Rudresha, RSC Adv. 2015, 5, 65870.

[13] J. Sun, G. Yu, L. Liu, Z. Li, Q. Kan, Q. Huo, J. Guan, Catal. Sci.

Technol. 2014, 4, 1246.

[39] M. Mohammadikish, M. Masteri‐Farahani, S. Mahdavi,

J. Magn. Magn. Mater. 2014, 354, 317.

10 of 10

PAYAMI ET AL.

[40] M. Herbert, F. Montilla, R. Moyano, A. Pastor, E. Álvarez, A.

[50] A. Tadjarodi, S. Mirzakhani, M. Masteri‐Farahani, React. Kinet.

Mech. Catal. 2017, 120, 593.

Galindo, Polyhedron 2009, 28, 3929.

[51] M. Herbert, F. Montilla, A. Galindo, J. Mol. Catal. A 2011,

338, 111.

[41] Z. Li, S. Wu, D. Zheng, H. Liu, J. Hu, H. Su, J. Sun, X. Wang, Q.

Huo, J. Guan, Q. Kan, Appl. Catal. A 2014, 470, 104.

[52] M. Bagherzadeh, M. Zare, M. Amini, T. Salemnoush, S.

[42] A. Sakthivel, J. Zhao, G. Raudaschl‐Sieber, M. Hanzlik, A. S.

Chiang, F. E. Kühn, Appl. Catal. A 2005, 281, 267.

Akbayrak, S. Özkar, J. Mol. Catal. A 2014, 395, 470.

[53] M. Masteri‐Farahani, F. Farzaneh, M. Ghandi, Catal. Commun.

2007, 8, 6.

[43] M. Masteri‐Farahani, F. Farzaneh, M. Ghandi, J. Mol. Catal. A

2006, 248, 53.

[44] S. M. Bruno, S. S. Balula, A. A. Valente, F. A. A. Paz, M.

Pillinger, C. Sousa, J. Klinowski, C. Freire, P. Ribeiro‐Claro, I.

S. Gonçalves, J. Mol. Catal. A 2007, 270, 185.

SUPPORTING INFORMATION

Additional Supporting Information may be found online

in the supporting information tab for this article.

[45] M. Shokouhimehr, Y. Piao, J. Kim, Y. Jang, T. Hyeon, Angew.

Chem. Int. Ed. 2007, 46, 7039.

[46] Y. Li, X. Fu, B. Gong, X. Zou, X. Tu, J. Chen, J. Mol. Catal. A

2010, 322, 55.

How to cite this article: Payami F, Bezaatpour

A, Eskandari H. Excellent alkene epoxidation

catalytic activity of macrocyclic‐based complex of

dioxo‐Mo(VI) on supermagnetic separable

nanocatalyst. Appl Organometal Chem. 2017;e3986.

https://doi.org/10.1002/aoc.3986

[47] G. Grivani, S. Tangestaninejad, M. H. Habibi, V. Mirkhani, M.

Moghadam, Appl. Catal. A 2006, 299, 131.

[48] M. Masteri‐Farahani, Z. Kashef, J. Magn. Magn. Mater. 2012,

324, 1431.

[49] M. Masteri‐Farahani, S. Abednatanzi, Appl. Catal. A 2014,

478, 211.

Article Doi

Excellent alkene epoxidation catalytic activity of macrocyclic-based complex of dioxo-Mo(VI) on supermagnetic separable nanocatalyst

DOI: 10.1002/aoc.3986

Source and publish data:

Authors:

Article abstract of DOI:10.1002/aoc.3986

Full text of DOI:10.1002/aoc.3986

Products guided by the article

R&D Labs maybe for 217320-94-0

Relevant to this article

Hot Product