Cu@furfural imine-decorated halloysite as an efficient heterogeneous catalyst for promoting ultrasonic-assisted A3 and KA2 coupling reactions: A combination of experimental and computational study

Article abstract of DOI:10.1039/c7nj02272g

Halloysite nanoclays (HNTs) were functionalized with (3-chloropropyl) trimethoxysilan and subsequently reacted with thiosemicarbazide and furfural to furnish furfural imine functionalized HNTs, which could serve as an efficient support for immobilization

Full text of DOI:10.1039/c7nj02272g

View Article Online
View Journal
NJC
Accepted Manuscript
This article can be cited before page numbers have been issued, to do this please use: S. Sadjadi, T.
Hosseinnejad, M. Malmir and M. M. Heravi, New J. Chem., 2017, DOI: 10.1039/C7NJ02272G.
This is an Accepted Manuscript, which has been through the
Volume 40 Number
1 January 2016 Pages 1–846
Royal Society of Chemistry peer review process and has been
accepted for publication.
NJC
Accepted Manuscripts are published online shortly after
New Journal of Chemistry
www.rsc.org/njc
A journal for new directions in chemistry
acceptance, before technical editing, formatting and proof reading.
Using this free service, authors can make their results available
to the community, in citable form, before we publish the edited
article. We will replace this Accepted Manuscript with the edited
and formatted Advance Article as soon as it is available.
You can find more information about Accepted Manuscripts in the
author guidelines.
Please note that technical editing may introduce minor changes
to the text and/or graphics, which may alter content. The journal’s
standard Terms & Conditions and the ethical guidelines, outlined
in our author and reviewer resource centre, still apply. In no
event shall the Royal Society of Chemistry be held responsible
for any errors or omissions in this Accepted Manuscript or any
consequences arising from the use of any information it contains.
ISSN 1144-0546
PAPER
Jason B. Benedict et al.
The role of atropisomers on the photo-reactivity and fatigue of
diarylethene-based metal–organic frameworks
rsc.li/njc

Please do not adjust margins
New Journal of Chemistry
Page 1 of 19
View Article Online
DOI: 10.1039/C7NJ02272G
Journal Name
ARTICLE
Cu@Furfural Imine-Decorated Halloysite as an Efficient
Heterogeneous Catalyst for Promoting Ultrasonic-Assisted A3 and
KA2 Coupling Reactions: A Combination of Experimental and
Computational Study
Received 00th January 20xx,
Accepted 00th January 20xx
DOI: 10.1039/x0xx00000x
Samahe Sadjadi *a, Tayebeh Hosseinnejad*b, Masoumeh Malmirb, Majid M. Heravi b
www.rsc.org/
Halloysite nanoclay (HNTs) was functionalized with (3-chloropropyl) trimethoxysilan and subsequently reacted with
thiosemicarbazide and furfural to furnish furfural imine functionalized HNTs, which could serve as an efficient support for
immobilization of copper species. The obtained catalyst, Cu@HNTs-T-F, was fully characterized using SEM/EDX, FTIR, ICP,
TGA, XRD and BET. To present a theoretical description for experimental features of Cu@HNTs-T-F nano catalyst, we
modeled and computationally assessed two coordination modes between copper acetate and HNTs-T-F ligand in the gas
and solution phases. In this line, the mathematical properties of electron density functions were calculated and analyzed
topologically via density functional theory (DFT) and quantum theory of atoms in molecules (QTAIM) approaches.
Encouraged by our computational results, the catalytic activity of this new catalyst was studied for A3 and KA2 coupling
reactions of aldehydes or ketone, phenyl acetylene and amines under green, ultrasonic-assisted condition. The results
established that the catalyst could promote the reaction to furnish the corresponding propargylamine derivatives in high
yields in very short reaction times. Studying the reusability of the catalyst confirmed that the catalyst could be recovered
and reused up to four times with only a negligible loss of the catalytic activity, indication the efficiency of the
functionalized HNTs on anchoring the copper species. ICP-AES analysis established very low leaching of copper species
upon reusing. This observation was attributed to the interactions of heteroatoms in functionalized HNTs with copper.
Moreover, the results confirmed the heterogeneous nature of the catalysis.
Introduction
The importance of propargylamines arise from their utility as metals render this process costly. Many studies have been
synthetic versatile intermediates for the synthesis of broad focused on developing an efficient and green strategy due to the
range of chemicals such as natural products, peptide isosteres, significance of this class of compounds 8-9
.
polyfunctional amino derivatives and different N-heterocycles Halloysite nanoclay (HNTs), with general formula of
such as β-lactams 1-2. To date various protocols and catalysts (Al2(OH)4Si2O5·2H2O) possess high surface area, tubular
such as silver, zinc, nickel, cobalt, iron, gold and copper-based morphology and high mechanical strength. They belongs to the
catalysts have been used for promoting terminal alkyne C–H class of kaolinite group hydrated layered aluminosilicate 10-11. In
bond activation and subsequently the reaction of activated HNTs a monolayer of water separates the unite layers in HNTs.
alkyne with amines and aldehydes, referred as A3 coupling Moreover, the exterior and interior surfaces of HNTs are
reaction, to furnish the corresponding propargylamines2-6
Although A3 coupling reaction is a superior method compared to outer surface while the octahedral gibbsite Al(OH)3 sheet forms
traditional protocols for the synthesis of propargylamines, i.e. the inner surface 12
.
chemically different. Tetrahedral SiO4 groups are located in the
.
direct amination of propargyl halides, propargylic triflates, Recently, functionalization of the surface of the HNTs is
propargylic phosphates 2-4, or addition of alkynylmetal reagents considered as a potent method for modification of the features
to imines 7, it is a log process that mostly need high temperature of HNTs and expanding their applications. Notably, both surfaces
or inert atmosphere. Moreover, using transition or precious of HNTs can be chemically modified. As an example Kepert et al.
functionalized the surface of the HNTs by using γ-
aminopropyltriethoxysilane (APTES)
characteristics. In another attempt, HNTs was amine-
functionalized by N-β-aminoethyl-γ-aminopropyl
trimethoxysilane and then used for deposition of ultrafine noble
13
and studied its
a.Gas Conversion Department, Faculty of Petrochemicals, Iran Polymer and
Petrochemical Institute, Tehran, Iran. PO Box
samahesadjadi@yahoo.com. and s.sadjadi@ippi.ac.ir
14975-112, E-mail:
b.Department of Chemistry, Alzahra University, Vanak, Tehran, Iran. PO Box
1993891176, E-mail: tayebeh.hosseinnejad@alzahra.ac.ir.
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 1
Please do not adjust margins

Please do not adjust margins
New Journal of Chemistry
Page 2 of 19
View Article Online
DOI: 10.1039/C7NJ02272G
ARTICLE
Journal Name
metallic nanoparticles such as Pd, Pt and Rh 14. In this line, Du et al. reported immobilization of Pt nanoparticles on HNTs amine
functionalized with APTES for catalytic purposes 15. Moreover, aluminum-backed plates of silica gel 60 F254, visualized, using
APTES functionalized HNTs was used for introduction of PVP- ultraviolet light. Melting points were determined in open
PdCl2 and subsequent reduction for formation of Pd (0) capillaries using an Electrothermal 9100 without further
nanoparticles for using in catalysis 16. More sophisticated corrections. 1H NMR and 13C NMR spectra were recorded on
functionalities such as poly(N-isopropylacrylamide) (PNIPAAM) Bruker DRX-400 spectrometer at 400 and 100 MHz respectively.
was also covalently grafted on HNTs for supporting Pd Catalyst characterization was carried out by applying various
nanoparticles 17. All these reports are indicative of the promising
techniques including SEM/EDX, TGA, FTIR, XRD, BET and ICP-AES.
utility of functionalized HNTs for immobilization of various
FTIR spectra were obtained by employing PERKIN-ELMER- Spectrum
nanoparticles 11, 18. The pure HNTs as well as its functionalized
65 instrument. SEM/EDX analyses were recorded by a Tescan
form are propitious materials for using as drug and enzyme
19
carriers and catalyst supports 20-21. Additionally, HNTs proved
instrument, using Au-coated samples and acceleration voltage of 20
their utilities for membrane for gas separation 22, photo
kV. Room temperature powder X-ray diffraction patterns were
degradation 23, water treatment
and optical, magnetic and
24-25
obtained by using a Siemens, D5000. CuKα radiation from a sealed
electrical applications 20
.
tube. The BET analyses were performed using BELSORP Mini II
instrument. Prior to BET analyses, the samples were degassed at
423 K for 3 h. Thermo gravimetric analysis (TGA) was performed on
a METTLER TOLEDO thermo gravimetric analysis apparatus with a
heating rate of 10 °C min-1 from 50 to 600 °C under N2 atmosphere.
The used ultrasonic apparatus for promoting the organic
transformations was Bandelin HD 3200 with output power of 150 W
and tip TT13. Notably, all of compounds were known and were
identified by comparison of their melting point and spectroscopic
data with those of reliable compounds. 1H and 13C NMR spectra of
chosen compounds are reported and specified as supplementary.
On the other hand, the improvement and extension in the
application of HNTs such as their usage in the encapsulation of
nonpolar chemicals for controlled release and nano-containers
applications depends strongly on their surface chemical and
physicochemical properties. However, the low activity of HNTs
external surface results in weaker interfacial interactions and
lowering the efficiency of HNTs for reinforcement and dispersion
26-29
.
In continuation of our attempt to introduce heterogeneous and
reusable catalysts
30-35
for promoting various organic reactions and
developing green and environmentally benign protocols for
21, 35-40
Cl-Functionalization of HNTs: Synthesis of HNTs-Cl
efficient synthesis of chemicals
and also armed with our
To introduce Cl functionality on HNTs, HNTs (1.2 g) was
dispersed in 60 mL dry toluene and subsequently (3-
chloropropyl) trimethoxysilan (4 mL) was added drop wise. The
resulting mixture was subjected to ultrasonic irradiation of
power 100 W for 0.5 h. The dispersed suspension was then
reflux under inert (N2) atmosphere for 24 h at 110 °C. Upon
completion of the reaction, the precipitate was separated by
simple filtering. The functionalized clay was obtained by washing
with dried toluene repeatedly and drying at 100 °C overnight.
previous computational modeling of structural, electronic and
thermochemical properties of heterogeneous nanocatalysts 1-7, 39, 41-
44, herein, we present a novel heterogeneous catalyst based on
functionalization of HNTs with (3-chloropropyl) trimethoxysilan,
thiosemicarbazide and furfural and incorporation of copper species.
The catalytic activity of the catalyst, Cu@HNTs-T-F, was studied for
A3 and KA2 coupling reaction of aldehydes or ketone, phenyl
acetylene and amines under ultrasonic irradiation in aqueous media
(Scheme 1). Furthermore, the reusability of the catalyst for four
reaction runs was studied. The nature of the catalysis was also
determined by investigating the leaching of the copper species by
using ICP-AES analysis. Considering the importance of
understanding the surface chemical and physicochemical
properties, we also concentrated on the computational
modeling of HNTs surface and their functionalization modes to
describe and predict immobilization behavior of copper on HNTs
surface. Strictly speaking, we concentrated on the quantitative
description of structural and electronic features of interactions
between copper acetate (denoted as Cu(OAc)2) and
thiosemicarbazide functionalized HNTs modified with furfural
Incorporation of thiosemicarbazide: synthesis of HNTs-T
Thiosemicarbazide (0.5 g) was added to a suspension of HNTs-Cl
(1g) in dry toluene (50 mL) in the presence of catalytic amount
of trietylamine (1 mL). The resulting mixture was refluxed at 110
°C for 24 h. Upon completion of the reaction, the precipitate was
filtered off and washed with dry toluene repeatedly. HNTs-T was
obtained after drying at 100 °C overnight.
Imine functionalization of HNTs: Synthesis of HNTs-T-F
The imine functionalization was achieved by dissolving furfural
(5 mL) in the stirring suspension of HNTs-T in MeOH (50 mL)
followed by refluxing for 18 h. The condensation reaction could
be visually detected by changing the color of the mixture into
deep yellow. Upon completion of the reaction, the resulting
solid was filtered off, washed with hot MeOH repeatedly and
dried at 100 °C overnight.
45
(denoted as HNTs-T-F) via density functional theory (DFT) and
quantum theory of atoms in molecules (QTAIM) 46 approaches.
Eexperimental
Introduction of Cu: synthesis of Cu@HNTs-T-F
Materials and instruments
To incorporate copper species, HNTs-T-F (2g) was suspended in
toluene (50 mL) and stirred to furnish a homogeneous
suspension. Subsequently, copper (II) acetate (0.4 g) was added
to the suspension and the resulting mixture was refluxed for 18
h. Upon proceeding the reaction, the change in the color of the
mixture from yellow into green could be observed. After the end
of the reaction, the precipitate was filtered off and washed with
toluene for several times.
All chemicals and reagents, including aldehydes, amines, ketone,
phenyl acetylene, halloysite clay, toluene, tiosemicarbazide,
furfural, ethanol, (3-chloropropyl) trimethoxysilan and Cu(OAc)2
were analytical grade reagents, purchased from Sigma-Aldrich,
and used without further purification. The progress of the
organic reactions were monitored by TLC on commercial
2 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Please do not adjust margins
Page 3 of 19
Journal Name
New Journal of Chemistry
View Article Online
DOI: 10.1039/C7NJ02272G
ARTICLE
Scheme 1. A3 and KA2 coupling reactions
The final catalyst, Cu@HNTs-T-F, was obtained by drying the
precipitated at 100 °C overnight. The schematic procedure for
the synthesis of the catalyst is depicted in Figure 1.
Results and discussion
Catalyst characterization
General procedure for A3 coupling reaction
The SEM/EDX images of Cu@HNTs-T-F are shown in Figure 2. As
obvious, in the hybrid catalyst the tubular morphology of the
pure HNTs is still observable. However, in comparison to pure
HNTs (Figure 1 in supporting information), the catalyst showed
more aggregated morphology. This can establish that
functionalization of HNTs and incorporation of copper species
affects the morphology of HNTs. This observation can be
attributed to the successful functionalization of HNTs and
electrostatic interactions of hetero-atoms in the functionality
with copper species.
Stoichiometric amounts of the reagents including aldehyde (1
mmol), amine (1 mmol) and phenyl acetylene (1 mmol) were
mixed in H2O. Subsequently, catalytic amount of Cu@HNTs-T-F
(0.02 g) was added to the mixture and the resulting mixture was
subjected to ultrasonic irradiation with power of 100 W at
ambient temperature for appropriate reaction time. The
progress of the reaction was monitored by TLC. Upon
completion of the reaction, Cu@HNTs-T-F was simply separated
by filtration. The filtrate was concentrated to furnish a
The EDX analysis of the catalyst indicates the presence of Si, Al
and O atoms, which can be the representative of HNTs
precipitate which was subsequently purified by column framework. Moreover, the presence of C, N, O and S can confirm
the incorporation of organic motifs, i.e. furfural and
thiosemicarbazide. Finally, the observation of Cu atom in EDX
analysis can confirm the successful immobilizing of copper
spices.
chromatography or recrystallized from hot EtOH. Notably, the
recovered catalyst was washed with the mixture (1:1) of
H2O/EtOH and dried at 90 °C overnight for reusing in successive
reaction runs.
Figure 1. The possible formation process of Cu@HNTs-T-F catalyst
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 3
Please do not adjust margins

Please do not adjust margins
New Journal of Chemistry
Page 4 of 19
View Article Online
DOI: 10.1039/C7NJ02272G
ARTICLE
Journal Name
Figure 2. The SEM-EDX images of Cu@HNTs-T-F
HNTs
Cu(OA)2
Figure 3. The TEM image of fresh Cu@HNTs-T-F
4 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Please do not adjust margins
New Journal of Chemistry
Page 5 of 19
Journal Name
View Article Online
DOI: 10.1039/C7NJ02272G
ARTICLE
identical and the catalyst exhibited the characteristic peaks of
To further characterize the catalyst, the TEM images of HNTs. This observation established that the introduction of
Cu@HNTs-T-F was recorded, Figure 3. As shown in Figure 3, the functionalities to HNTs and incorporation of copper species did
tubular morphology of pure HNTs is preserved upon not induce the collapse of HNTs framework. This was further
functionalization and copper incorporation.
confirmed by BET analysis (vide infra). Notably, the unchanged
interlayer distances of Cu@HNTs-T-F implied that the
The FTIR spectra of HNTs-T-F and Cu@HNTs-T-F are illustrated in intercalation of organic motifs and copper species did not take
Figure 4. Both spectra exhibited bands at 3705 cm-1 and 3685 place within the interlayer of HNTs, but on the surface and the
cm-1 which are the representative of internal and external edges of the HNTs tubes. This fact was previously observed and
hydroxyl groups of HNTs framework. Additionally, the reported by Kepert et al 13
.
characteristic bands of Al-O-Si vibration and the interlayer water Notably, in XRD pattern of Cu@HNTs-T-F no distinguished peak
can be observed at 561 cm-1 and 1656 cm-1 respectively. The was detected for copper. According to the literature, this
presence of bands at 2972 cm-1 and 1085 cm-1 which are the observation can be attributed to the low amount of copper as
representative of –CH2 stretching and Si–O stretching, well as its high dispersion 48
respectively can confirm the successful attachment of (3-
.
chloropropyl) trimethoxysilan.30 The observed band at 1383 cm-1 The TGA thermogram of Cu@HNT-T-F, Figure 6, exhibited four
can be attributed to C=S group. Two bands at 1564 cm-1 and degradation stages over the range of 50-600 °C. The first
1442 cm-1 can be assigned to the asymmetric and symmetric degradation stage can be attributed to the loss of absorbed
vibrations, respectively, of the acetate ions and confirm the water. The next two degradation stages can be observed at 300
incorporation of copper. Furthermore, the band at 1656 cm-1 is and 370 ºC and can be assigned to the thermal decomposition of
representative of imine functional group. according to the organic functionalities.
literature, the shift of imine band to lower wavelength can be
due to the coordination to copper.47
The XRD pattern of Cu@HNTs-T-F was recorded and compared
with that of pure HNTs, Figure 5. As shown, the characteristic
peaks of HNTs can be observed at 8°, 12°, 20°, 25°, 35°, 54° and
62.8° (JCPDS No. 29-1487). The obtained XRD pattern is in good
accordance with the previously reported patterns for HNTs in
the literature 10, 13. The comparison of the XRD patterns of the
catalyst and pure HNTs showed that both patterns were
Figure 4. The FT-IR spectra of (a) HNTs-T-F (b) Cu@HNTs-T-F
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 5
Please do not adjust margins

Please do not adjust margins
New Journal of Chemistry
Page 6 of 19
View Article Online
DOI: 10.1039/C7NJ02272G
ARTICLE
Journal Name
Figure 5. The XRD pattern of Cu@HNT-T-F and pure HNTs
The final degradation stage can be detected at about 500 °C, which HNTs, which can be attributed to the degradation of functionalities.
can be due to the dehydroxylation of the matrix. Notably, the TGA TGA analysis was also applied for estimating the content of organic
thermogram of Cu@HNT-T-F is different from that of pure HNTs, functionality in Cu@HNT-T-F. This value was calculated to be about
Figure 6, in which only two degradation stages were reported for 19.6 wt%. To calculate the content of copper in the catalyst, the
loss of water (about 200 °C) and the rearrangement of ions in the digestion was accomplished in concentrated hydrochloric and nitric
metakaolin state (about 500 °C) 49-50. This observation confirmed acids solution. Subsequently, the analysis of the obtained extract
that functionalization of HNTs and incorporation of copper can alter was performed by using ICP-AES. Using this method, the content of
the TGA of the pure HNTs and more degradation stages were copper was estimated to be about 4 wt%.
observed in thermogaram of the catalyst compared to that of pure
Figure 6. The TGA analysis of pure HNTs (a) and Cu@HNT-T-F (b)
Nitrogen adsorption–desorption isotherm of Cu@HNT-T-F was that of HNTs. As obvious, upon fictionalization and copper
obtained to study the textural features of the catalyst, Figure 7. As incorporation, the textural properties of the catalyst changed
depicted, the shape of the isotherm is of the type II nitrogen remarkably and average pore diameter, specific surface area and
13
adsorption–desorption isotherms with H3 hysteresis loops
and total pore volume increased in Cu@HNT-T-F. According to the
confirms the porous structure of the catalyst. In Table 1, the previous reports, this observation can be attributed to the presence
textural properties of Cu@HNT-T-F is tabulated and compared with of copper species on the surface of HNTs 51
.
6 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Please do not adjust margins
New Journal of Chemistry
Page 7 of 19
View Article Online
DOI: 10.1039/C7NJ02272G
Journal Name
ARTICLE
Computational study
As it was discussed earlier, the detailed information about the
surface chemistry of HNTs and their functionalized moieties plays
an important role in design of immobilization behavior of
nanoparticles to improve their performance and extend their
applications 26-29. In this light, we concentrated on the quantitative
description of structural and electronic features of interactions
between copper acetate (denoted as Cu(OAc)2) and
thiosemicarbazide functionalized HNTs modified with furfural
45
(denoted as HNTs-T-F) via density functional theory (DFT)
and
quantum theory of atoms in molecules (QTAIM) 46 approaches.
In this respect, we have designed an appropriate model for HNTs-T-
F ligand and its complex with copper acetate, (illustrated in Scheme
2). As it is depicted in scheme 2, two coordination modes were
designed to describe the metal-ligand interactions in Cu@HNTs-T-F
complex model, denoted as Cu@O-HNTs-T-F (copper coordinates to
oxygen of furfural ring) and Cu@S-HNTs-T-F (copper coordinates to
sulfur of thiosemicarbazide compound), respectively. It is
worthwhile to note that the proposed structural model for HNTs as
1:1 layered aluminosilicates can be considered as an effective
model for comparative investigation of metal-ligand interaction
strength.
Figure 7. Nitrogen adsorption-desorption isotherms of the catalyst
Table 1. Textural properties of the catalyst and pure HNTs
Sample
Cu@HNT-T-F
HNTs
SBET (m2g-1)
88.6
Average pore
diameter (nm)
Total pore volume
(cm3 g-1)
35.5
0.78
51
15.2
0.19
Scheme 2. The designed model for HNTs-T-F and its two coordinating modes with copper acetate, denoted as Cu@O-HNTs-T-F and Cu@S-
HNTs-T-F, respectively
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 7
Please do not adjust margins

Please do not adjust margins
New Journal of Chemistry
Page 8 of 19
View Article Online
DOI: 10.1039/C7NJ02272G
ARTICLE
Journal Name
Figure 8. The energy-minimized structure of HNTs-T-F ligand, Cu@O-HNTs-T-F and Cu@S-HNTs-T-F complexes obtained at M08HX/6-31G*
level of theory. Note that M08HX/6-311+G** calculated values of bond orders (bond lengths) for some key bonds in the coordination
sphere of Cu@O-HNTs-T-F and Cu@S-HNTs-T-F complexes have been reported.
More importantly, this model has a reliable comprise between This comparative analysis demonstrates that copper acetate has a
52-
accuracy and time saving efficiency of computational procedure
more tendency to bind with nitrogen than oxygen of furfural and
54. In the first step, we determined the optimized structure of HNTs- sulfur of thiosemicarbazide. On the other hand, to investigate the
T-F and two Cu@O-HNTs-T-F, Cu@S-HNTs-T-F complexes at variation of bond orders through the complexation, we reported
M08HX/6-31G* level of theory.
the M08HX/6-311+G** calculated values of some selected bond
orders (bond lengths) in ligand, Cu@O-HNTs-T-F and Cu@S-HNTs-T-
F complexes in Table 2.
The harmonic frequency analysis was used to confirm the found
structures correspond to minima. It is noteworthy to state that
M08HX functional has been introduced as a modern hybrid meta- The comparison of bond order calculated values in HNTs-T-F ligand
GGA (generalized gradient approximation) exchange-correlation with its corresponding bonds in Cu@O-HNTs-T-F and Cu@S-HNTs-T-
functional combined with Hartree-Fock exchange contribution 55. In F complexes, reveals that the bond order of C-O in furfural ring
the case of copper, the effective core potentials (ECP), LANL2DZ, and also C−N and C-S of thiosemicarbazide decreases through
were used together with the accompanying basis set to describe the complications in Cu@O-HNTs-T-F and Cu@S-HNTs-T-F complexes
valence electron density 56. All DFT computations were performed that is in a reversed trend with the variation of calculated bond
using GAMESS suite of programs 57
.
distance values. This character can be mainly imputed to the
donation of shared electrons from these chemical bonds to copper
ions that also confirm by reported FT-IR spectroscopic data. In the
next step, we concentrated on the computational modeling of the
solvent effect in the synthesis of Cu@HNTs-T-F nanocatalyst. In this
respect, we evaluated comparatively the bond orders of Cu-N, Cu-O
and Cu-S in Cu@O-HNTs-T-F and Cu@S-HNTs-T-F complexes, in the
presence of toluene and ethanol as solvents via polarized
continuum model (PCM) 58. It should be noticed that better
immobilization and smaller size of copper NPs on functionalized
HNTs have been observed in toluene solution in comparison with
ethanol 47, 59. Our comparative assessment on M08HX/6-311+G**
calculated bond orders of Cu-N, Cu-O (in Cu@O-HNTs-T-F complex)
and Cu-S (in Cu@S-HNTs-T-F complex) in toluene and ethanol
The optimized geometry of HNTs-T-F and two Cu@O-HNTs-T-F and
Cu@S-HNTs-T-F complexes calculated at M08HX/6-31G* level of
theory have been shown in Figure 8. Furthermore, we reported
M08HX/6-311+G** bond orders and bond lengths calculated values
for some key bonds in the coordination sphere of Cu@O-HNTs-T-F
and Cu@S-HNTs-T-F complexes. The comparative assessment of the
bond order calculated values in Cu@O-HNTs-T-F and Cu@S-HNTs-T-
F complexes indicate that the Cu-N interaction strength in Cu@O-
HNTs-T-F complex is higher than Cu-O and Cu-S in the Cu@O-HNTs-
T-F and Cu@S-HNTs-T-F complexes (0.82, 0.61 and 0.43 for
calculated Cu-N, Cu-O and Cu-S bond order values in Cu@O-HNTs-T-
F and Cu@S-HNTs-T-F complexes, respectively).
8 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Please do not adjust margins
New Journal of Chemistry
Page 9 of 19
Journal Name
View Article Online
DOI: 10.1039/C7NJ02272G
ARTICLE
solution phases confirmed that Cu-N interaction in Cu@O-HNTs-T-F Cu@S-HNTs-T-F complexes as inputs to AIM2000 program package
complex is stronger than Cu-O and Cu-S in Cu@O-HNTs-T-F and 61. In Table 4, we reported the calculated values of some QTAIM
Cu@S-HNTs-T-F complexes (as was reported in Table 3).
reliable indicators including electron density (ρ_b), its laplacian
(∇^2 ρ_b), electronic kinetic energy density (G_b), electronic
potential energy density (V_b), total electronic energy density
(H_b), |V_b | G_b and delocalizaꢀon index (DI) for some selected
critical points in Cu@O-HNTs-T-F and Cu@S-HNTs-T-F complexes.
We also displayed the QTAIM molecular graphs of Cu@O-HNTs-T-F
and Cu@S-HNTs-T-F complexes including all bond and ring critical
points and their associated bond paths in Figure 9.
Table 2.
The calculated values of some selected bond orders (bond
lengths) in ligand, Cu@O-HNTs-T-F and Cu@S-HNTs-T-F
complexes obtained at M08HX/6-311+G** level of theory.
Note that in Fig.7, we displayed the selected bonds in the
optimized structure of HNTs-T-F ligand.
As it is reported in Table 4, the small calculated values of electron
density and delocalization index in conjunction with the positive
values of ∇^2 ρ_b and small negative values of Hb and also 1<|V_b
Free ligand
Complex
bonded atoms
| G_b<2 calculated values can be aꢁributed to the nature of semi
Cu@O-HNTs-T-F
Complex
62
covalent-electrostatic interactions at Cu-N, Cu-O and Cu-S BCPs
.
However, comparison of the calculated electron density and
delocalization index values of Cu-N, Cu-O and Cu-S BCPs in Cu@O-
HNTs-T-F and Cu@S-HNTs-T-F complexes reveals that interaction of
copper cation with nitrogen is stronger than oxygen of furfural and
sulfur of thiosemicarbazide.
C-O
0.938(138.5 pm)
0.970(128.3 pm)
0.844(1.40.6 pm)
0.826(149.5 pm)
C-N
Cu@S-HNTs-T-F
Complex
C-S
1.184(176.7 pm)
0.970(128.3 pm)
1.136(179.5 pm)
0.942(135.4 pm)
Based on the concept of hard and soft acids and bases (HSAB)
theory, we can state that Cu2+ as a soft acid should bind with more
tendency to sulfur atom as a soft base than nitrogen atom as a hard
base that in an inverse trend with our calculated results. In this
context, it should be noticed that HSAB theory only assessed the
electronic effects of interactions with no consideration on the steric
and structural features of coordination. So, in order to assess the
coordination properties of copper(II) complexes with NSO ligands,
the electronic properties in conjunction with the structural aspects
of complexation should be considered. In x-ray single crystal
structure of these complexes, it has been observed that in the unit
cell-one molecule, there are several coordination modes and
geometries so that SNO ligands can act as a bidentate ligand with
N,O coordination sites with square planar geometry and also as a
tridentate ligand with N, S and O coordination sites and distorted
C-N
Table 3.
The obtained values of Cu-N, Cu-O and Cu-S bond orders in
Cu@O-HNTs-T-F and Cu@S-HNTs-T-F complexes in toluene and
ethanol solution phases, calculated at M08HX/6-311+G** level
of theory via PCM approach
Cu-O
Cu-N
Cu-S
Cu@O-HNTs-T-F
Cu@O-HNTs-
T-F
Cu@O-HNTs-T-F
square pyramidal geometry63-66
.
Toluene
Ethanol
0.932
0.878
0.717
0.695
0.511
0.472
Another important electronic feature that can be deduced via
concise analysis of QTAIM molecular graphs of Cu@O-HNTs-T-F and
Cu@S-HNTs-T-F complexes is the formation of N-H---O-C and C-H---
O-C intra-molecular interactions between acetate group and HNTs-
T-F ligand in Cu@O-HNTs-T-F and Cu@S-HNTs-T-F complexes,
respectively. The QTAIM calculated values of ρ_b (and ∇^2 ρ_b ) for
N-H---O-C and C-H---O-C bond critical points have been obtained
0.040au (0.142au) and 0.020au (0.075au), respectively. More
importantly, it can be seen that N-H---O-C and C-H---O-C intra-
molecular bondings lead to form additional rings with the requisite
ring critical points in Cu@O-HNTs-T-F and Cu@S-HNTs-T-F
complexes (with 0.037au and 0.013au electron density values,
More importantly, Cu-N bond order in Cu@O-HNTs-T-F complex has
larger calculated value in toluene solution in comparison with those
calculated in ethanol and so approves the previously reported
preference of toluene as solvent rather than ethanol in the
synthesis of HNTs catalysts 47, 59. On the other hand, to rationalize
and quantify the metal-ligand interaction strength we assessed the
topological properties of electron densities at the optimized
structure of Cu@HNTs-T-F complex models via QTAIM method 46, 60
.
respectively)
and consequently can stabilize metal-ligand
In this line, we applied the calculated M08HX/6-311+G** wave
function files for the optimized structures of Cu@O-HNTs-T-F and
interactions electronically.
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 9
Please do not adjust margins

Please do not adjust margins
New Journal of Chemistry
Page 10 of 19
View Article Online
DOI: 10.1039/C7NJ02272G
ARTICLE
Journal Name
Cu@O-HNTs-T-F Complex
Cu@S-HNTs-T-F Complex
Figure 9. QTAIM Molecular graph of Cu@O-HNTs-T-F and Cu@S-HNTs-T-F complexes obtained by topological analysis of M08HX/6-
311+G** electron density function. Bond Critical Points: green circles; Ring Critical Points: red circles; Bond Paths: grey lines.
Table 4.
Mathematical properties of BCPs associated to some selected bonds in Cu@O-HNTs-T-F and Cu@S-HNTs-T-F
complexes. The properties have been obtained via QTAIM analysis on M08HX/6-311+G**calculated wave function
of electron density.
DI
Cu@O-HNTs-T-F
Complex
Cu-N BCP
0.159
0.090
0.653
0.418
0.244
0.139
-0.325
-0.175
-0.080
-0.035
1.330
1.252
0.966
0.318
Cu-O BCP
Cu@S-HNTs-T-F
Complex
Cu-S BCP
Cu-C BCP
0.065
0.140
0.105
0.050
0.113
-0.074
-0.184
-0.023
-0.070
1.476
1.615
0.548
0.740
-0.064
10 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Please do not adjust margins
New Journal of Chemistry
Page 11 of 19
Journal Name
View Article Online
DOI: 10.1039/C7NJ02272G
ARTICLE
explained according to the cavitation phenomena 69-73. That is,
formation, growth and collapse of the cavities which led to the
formation of spots with high temperatures and pressures. This can
concentrate high amount of energy from the conversion of kinetic
energy of liquid motion into heating of the contents of the cavities
74. Notably, ultrasonic irradiation not only can enhance the rate of
Catalytic activity
To study the catalytic activity of the catalyst, the A3 coupling
reaction, which is an important coupling reaction in organic
chemistry, was selected as a model chemical reaction. Initially, to
confirm the necessity of the use of the catalyst, the reaction of
21
the chemical reactions but also influence the reaction pathway
74
and promoting chemical reactivity
.
In the next step, the
generality of this procedure was examined by using diverse range of
aldehydes with electron donating, electron withdrawing groups as
well as heterocyclic aldehydes for the synthesis of various
propargylamine derivatives (Table 5). Gratifyingly, all substrates
tolerated the reaction to furnish the corresponding products in
excellent yields in a very short reaction times (10-25 min). These
results clearly established the broad substrate scope of this
protocol. To elucidate the merit of Cu@HNTs-T-F and our
ultrasonic-assisted protocol, the efficiencies of previously reported
methodologies for promoting the model reaction were compared
with that of Cu@HNTs-T-F (Table 6). As obvious, various catalysts
such as CuI, CuCN and Cu2O-ZnO have been used for catalyzing this
reaction under different reaction conditions. Comparing the yield of
the model product, it can be seen that CuNPs/Mag Silica, Nafion-
NR50 and CuNPs/TiO2 exhibited inferior catalytic activities.
Moreover, the reaction times reported for these cases were very
longer than Cu@HNTs-T-F and the reactions proceeded at elevated
temperatures. In the cases of CuI, h-Fe2O3@DA/Ag, Cu2O-ZnO and
CuCN comparative yields were reported (using CuI led to slightly
higher yield). However, comparing the reaction conditions indicated
that Cu@HNTs-T-F furnishes the desired product in very shorter
reaction times. Furthermore, except CuI, all catalysts required
heating for promoting the reaction.
benzaldehyde, phenyl acetylene and morpholine as
a model
reaction was performed in the absence of the catalyst. The result
indicated that the presence of the catalyst is essential for obtaining
the desired product. Subsequently, in attempt to disclose a green
procedure for the synthesis of propargylamine, the model reaction
was performed under ultrasonic irradiation and the results
compared with those of obtained under solvent-free, refluxing and
stirring condition. The results established that the reaction rate of
the reaction performed under ultrasonic-assisted procedure was
remarkably lower than those of other methodologies. More
precisely, the model reaction under ultrasonic irradiation of power
100 W in the presence of 0.02 g catalyst in water completed in 15
min to furnish the desired product in excellent yield (96 %), while
the rates of this reaction under reflux and stirring condition in
water and the presence of the same amount of the catalyst or
solvent–free condition were 45 min, 60 min and 50 min
respectively. Moreover, the yields of the model product under
solvent-free, refluxing and stirring condition were lower, 90, 92 and
88% respectively. Hence, using ultrasonic irradiations was found as
a best methodology and the reaction condition was then optimized
by altering the reaction variables including solvent, catalyst amount
and the power of ultrasonic irradiation (Figure 10). As obvious, the
optimized solvent, catalyst amount and ultrasonic power were
found to be: water, 0.02 g and 100 W respectively. According to the
21,
literature
67-68, the effect of ultrasonic irradiation can be
Figure 10. Effects of loading of catalyst, duration of reaction and solvent for the synthesis of propargylamine
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 11
Please do not adjust margins

Please do not adjust margins
New Journal of Chemistry
Page 12 of 19
View Article Online
DOI: 10.1039/C7NJ02272G
ARTICLE
Table 5.
Journal Name
Synthesis of three-component reaction of derivatives aldehyde and ketone, secondary-amines and terminal alkynes catalyzed by Cu@HNTs-T-F
1-7
a [Ref]
Time
(min)
15
Yieldb
(%)
95
93
90
91
95
95
87
90
97
90
89
90
93
94
86
89
85
90
88
90
79
85
80
90
94
90
90
92
88
89
90
R1
R2
R3
3a: -(CH2)5-
R4
R5
Product
1a: C6H5
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
4a
4a
4a
4a
4a
4a
4a
4a
4a
4a
4a
4a
4a
4a
4a
4a
4a
4a
4a
4a
4a
4a
4a
4a
4a
4a
4a
4a
4a
5a
5b
5c
5d
5e
5f
5g
5h
5i
1b: p-Cl-C6H4
1c:p-NO2-C6H4
3a
3a
12
15
1d: p-Me-C6H4
3a
17
1e:p-MeO-C6H4
1f: o-OH-C6H4
1g: furfuryl
1h: 1-naphtyl
3a
3a
3a
3a
10
10
15
20
12
12
15
1a
1b
1c
3b:-(CH2)2-O-(CH2)2-
3b
3b
5j
5k
5l
1d
3b
12
1e
3b
5m
5n
5o
5
10
1f
3b
10
1g
3b
3b
15
17
1i: m-NO2-C6H4
1a
3c:C2H5
3a
C2H5
5q
6a
6b
6c
6d
6e
6f
20
1j: H
15
1j
3b
3c
10
15
20
17
22
30
25
25
1j
1k: C6H11
3a
1k
3b
3c
1k
1l: -(CH2)2-Me
3a
6g
6h
6i
1l
1l
3b
3c
2a: -(CH)5-
3a
6j
25
20
30
25
30
2a
2a
2a
2a
3b
3c
6k
6l
3a
4b: p-Me-C6H4
4c: p-F-C6H4
6m
6n
3b
a Reaction conditions: aldehydes 1a-k (1 mmol) or aliphatic ketone 2a (1 mmol), amines 3a-c (1.1 mmol), alkynes 4a-c (1.2 mmol), H2O (20 ml)
and Cu@HNTs-T-F (0.02 g) under ultrasonic irradiation (100 W) at room temperature.
b Isolated yield.
Table 6.
Comparison of Cu@HNTs-T-F with other recently reported acid catalysts for the synthesis of propargylamine (Scheme 1)
Catalyst
amount
CuI (15 mg)
Reaction conditions
(solvent/ temperature)
H2O/ r.t./ U.S
Time
(min)
45
15
60
Entry
Yield (%)
Ref
81
1
2
3
4
5
6
7
8
98
96
96
95
95
91
85
85
Cu@HNTs-T-F (20 mg)
h-Fe2O3@DA/Ag (10 mg)
Cu2O-ZnO (10 mg)
CuCN (2 mol%)
CuNPs/TiO2 (0.5 mol%)
Nafion-NR50 (350 mg)
CuNPs/MagSilica (10 mg)
H2O/ r.t./ 100 W
S.F./ 90 °C
S.F./ 100 °C
This work
82
76
83
84
32
85
60
[bmim]PF6/ S.F./ 120 °C
S.F./ 70 °C
CH3CN/ 70-80 °C/ N2 atm
S.F./ 100 °C/ under air
120
420
300
60
12 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Please do not adjust margins
New Journal of Chemistry
Page 13 of 19
Journal Name
View Article Online
DOI: 10.1039/C7NJ02272G
ARTICLE
structural features of the catalyst did not altered upon reusing.
In Figure 13 the XRD patterns of fresh and reused catalysts are
compared. As illustrated, both fresh and reused catalysts
exhibited the characteristic peaks of HNTs, implying that
reusing the catalyst did not diminish the tubular structure of
HNTs and the reused catalyst preserved its structure. Next, to
study the effect of the reuse and recovery on the morphology
of the catalyst, the SEM image of the reused and fresh
catalysts were compared, Figure 14. It was found that both
fresh and reused catalysts possessed almost similar
morphology in which both aggregates and rod like
morphologies could be detectable. This observation clearly
established that the reuse of the catalyst would not cause any
remarkable change on the morphology of the catalyst.
Moreover, the EDX analysis of the reused catalyst, Figure 14,
showed Si, Al, O atoms, which are representative of HNTs
structure as well as S, C and N, which could be attributed to
the organic functionality and Cu atom. This can prove that the
reused catalyst consisted of both organic functionality and
copper (as it was further confirmed by ICP-AES analysis),
indicating that reuse of the catalyst did not result in the
detachment of the organic moiety. Finally, the TEM image of
reused catalyst was obtained, Figure 14, and compared with
that of the fresh catalyst, Figure 3. The similarity of both
images could be considered as another proof for the stability
of the reused catalyst. All these analyses can confirm that the
catalyst was stable upon reusing and can be reused for the
successive reaction runs.
Reaction mechanism
The plausible reaction mechanism is illustrated in Scheme 3. As
depicted, the catalyst can activate the terminal C-H bond of
phenyl acetylene through formation of Cu-acetylide as an
intermediate. The catalyst can also accelerate the formation of
imine derived from reaction of amine and aldehyde by
activation of carbonyl group. The desired propargylamine can
be achieved through reaction of Cu-acetylide and imine.
Catalyst reusability
One of the most important features of a heterogeneous
catalyst is the capability of simple recovery and reusing. To
study the reusability of Cu@HNTs-T-F, the model reaction was
carried out in the presence of the fresh and recovered catalyst.
Precisely, the yield of the model reaction was investigated for
short reaction intervals between 2-12 min. After the first
reaction run, the catalyst was separated by simple filtration
and washed with the mixture (1:1) of H2O/EtOH and dried at
90 °C overnight and subjected for the next reaction run. The
yields of the model product in the presence of the fresh and
reused catalysts were compared, Figure 11. The results clearly
indicate that the catalyst preserved its catalytic activity upon
reusing and only a negligible loss of catalytic activity was
detected.
To investigate the leaching of the copper species and elucidate
whether the catalysis is heterogeneous, quenching experiment
was performed by filtering the reaction mixture and studying
the catalytic activity of the filtrate. It was found that the
reaction did not proceed in the filtrate, indicating the
suppressed leaching of the copper species. This finding was
also confirmed by using ICP-AES analysis, which established
almost no leaching of copper.
To study the stability of the reused catalyst and to see whether
the recovery and reuse of the catalyst can affect the
morphology and composition and phase of the catalyst, the
reused catalyst was characterized by FTIR, TEM, XRD, SEM and
EDX. In Figure 12 the FTIR spectra of both fresh and reused
catalysts are depicted. As shown in Figure 12, the FTIR spectra
of both catalysts are almost identical, indicating that the
Scheme 3. Plausible mechanism for the synthesis of propargylamine by Cu@HNTs-T-F
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 13
Please do not adjust margins

Please do not adjust margins
New Journal of Chemistry
Page 14 of 19
View Article Online
DOI: 10.1039/C7NJ02272G
ARTICLE
Journal Name
Figure 11. Reusability of the Cu@HNTs-T-F catalyst in A3 Coupling
Figure 12. The FTIR spectra of fresh Cu@HNTs-T-F (a) and after four runs (b)
14 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Please do not adjust margins
Page 15 of 19
Journal Name
New Journal of Chemistry
View Article Online
DOI: 10.1039/C7NJ02272G
ARTICLE
Figure 13. The XRD patterns of fresh Cu@HNTs-T-F (a) and after four runs (b)
Figure 14. The SEM (a), TEM (b) and EDX (c) images of Cu@HNTs-T-F catalyst after four runs
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 15
Please do not adjust margins

Please do not adjust margins
New Journal of Chemistry
Page 16 of 19
View Article Online
DOI: 10.1039/C7NJ02272G
ARTICLE
Journal Name
Spectral data for selected compounds
the excellent reusability of the catalyst is the merits of this
methodology.
1-(1,3-diphenylprop-2-ynyl)piperidine (Table 5, 5a): Pale yellow
oily liquid; 1H NMR (400 MHz, CDCl3, ppm) δ 1.45-1.49 (m, 2H),
1.58-1.65 (m, 4H), 2.59 (t, 4H), 4.81 (s, 1H), 7.31-7.40 (m, 6H), 7.53-
7.55 (m, 2H), 7.65-67 (d, J=7.6 Hz, 2H).
On the other hand, we computationally assessed the interaction of
copper acetate with HNTs-T-F via the design of two coordination
modes in Cu@HNTs-T-F complex model. The comparative analysis
of calculated bond orders and all QTAIM indicators demonstrates
that copper acetate has a more tendency to bind with nitrogen than
oxygen of furfural and sulfur of thiosemicarbazide moieties which
can predict and interpret the immobilization behavior of copper
acetate on functionalized HNTs. Moreover, concise analysis of
QTAIM molecular graphs of Cu@O-HNTs-T-F and Cu@S-HNTs-T-F
complexes shows the intra-molecular interactions between acetate
group and HNTs-T-F ligand in Cu@O-HNTs-T-F and Cu@S-HNTs-T-F
complexes that leads the formation of additional ring critical points
with a considerable electronic stabilizing effect on metal-ligand
interaction.
1-(1-(naphthalen-3-yl)-3-phenylprop-2-ynyl)piperidine (Table
5, 5h): Yellow oil; 1H NMR (400 MHz, CDCl3, ppm): δ 1.47-1.51 (m,
2H), 1.60-1.67 (m, 4H), 2.64 (t, 4H), 4.97 (s, 1H), 7.36-7.40 (m, 3H),
7.48-7.52 (m, 2H), 7.58-7.61 (m, 2H), 7.79 (dd, J1=J2=8.4 Hz, 1H),
7.85-7.91 (m, 3H), 8.11 (s, 1H); 13C NMR (100 MHz, CDCl3, ppm) d
24.4, 26.2, 50.8, 62.5, 86, 88.1, 123.3, 125.8, 125.9, 126.7, 127.2,
127.5, 127.7, 128.1, 128.12, 131.8, 132.9, 133.1, 136.3.
N,N-diethyl-1,3-diphenylprop-2-yn-1-amine (Table 5, 5q): Pale
yellow oily liquid; 1H NMR (400 MHz, CDCl3, ppm) δ 1.04 (m, 6H),
2.36-2.62 (m, 4H), 5.19 (s, 1H), 7.15-7.27 (m, 4H), 7.29-7.38 (m, 3H),
7.39-7.41 (m, 2H).
4-(3-phenylprop-2-ynyl)morpholine (Table 5, 6b): yellow oil; 1H
NMR (400 MHz, CDCl3, ppm) δ 2.64-2,67 (m, 6H), 3.52 (s, 3H), 3.69-
3.71 (m, 1H), 3.77-3.79 (m, 6H), 7.28-7.31 (m, 4H), 7.43-7.46 (m,
2H).
Acknowledgements
The authors appreciate partial financial supports from Alzahra
University and Iran Polymer and Petrochemical Institute. MMH is
also thankful to Iran National Science Foundation for the Individual
given grant. S. Sadjadi and M. M. Heravi are thankful to Iran
National Science Foundation (INSF) for supporting this research
under contract No. 95834576.
4-(1-phenylhex-1-yn-3-yl)morpholine (Table 5, 6h):Yellow oil;
1H NMR (400 MHz, DMSO-d6, ppm) δ 0.97 (m, 3H), 1.45-1.75 (m,
4H), 2.67−2.70 (m, 2H), 2.79−2.83 (m, 2H), 3.82-4.13 (m, 1H), 4.15-
4.17 (m, 4H), 7.46−7.50 (m, 3H), 7.62−7.64 (m, 2H).
4-(1-(2-phenylethynyl)cyclohexyl)morpholine (Table 5, 6k):Pale
yellow oily liquid; 1H NMR (400 MHz, CDCl3, ppm) δ 1.28-1.30 (m,
1H), 1.52 (m, 2H), 1.63-1.67 (m, 3H), 1.73 (br.s, 2H), 2.03-2.05 (m,
2H), 2.74 (br.s, 4H), 3.78 (br.s, 4H), 7.27 (m, 3H), 7.44-7.45 (m, 2H),
13C NMR (100 MHz, CDCl3, ppm) δ 22.7, 25.7, 35.4, 46.6, 58.8, 67.4,
86.4, 89.8, 123.4, 127.7, 128.1, 131.7.
Notes and references
1.
G. Villaverde, A. Corma, M. Iglesias and F. Sanchez, ACS
Catal. , 2012, 2, 399−406.
1-(1-(2-p-tolylethynyl)cyclohexyl)piperidine
(Table
5,
2.
S. V. Katkar and R. V. Jayaram, RSC Adv., 2014, 4, 47958–
47964.
L. F. Bobadilla, T. Blasco and J. A. Odriozola, Phys. Chem.
Chem. Phys., 2013, 15, 16927--16934.
M. Hosseini-Sarvari and F. Moeini, New J. Chem., 2014,
38, 624-635.
6m):Yellow oil; 1H NMR (400 MHz, CDCl3, ppm) δ 1.39-1.93 (m,
16H), 2.17-2.20 (m, 2H), 2.53 (s, 3H), 2.73-2.83 (m, 2H), 7.26-7.27
(m, 3H), 7.46-7.48 (m, 2H); 13C NMR (100 MHz, CDCl3, ppm) δ 21.32,
23.4, 24.4, 25, 26.7, 37.6, 47.9, 58.8, 85.4, 92.1, 123, 127.6, 128.3,
133.
3.
4.
5.
B. J. Borah, S. J. Borah, K. l. Saikia and D. K. Dutta, Catal.
Sci. Technol., 2014, 4, 4001-4009.
4-(1-( (4-fluorophenyl)ethynyl)cyclohexyl)morpholine (Table 5,
6n): Yellow oil; H NMR (400 MHz, DMSO-d6, ppm) δ 1.26-1.34 (m,
1
6.
T. Zeng, W.-W. Chen, C. M. Cirtiu, A. Moores, G. Song and
C.-J. Li, Green Chem. , 2010, 12, 570–573.
M. J. Albaladejo, F. Alonso, Y. Moglie and M. Yus, Eur. J.
Org. Chem., 2012, 2012, 3093–3104.
1H), 1.57-1.62 (m, 2H), 1.69-1.78 (m, 3H), 1.80-1.86 (m, 2H), 2.00-
2.02 (m, 2H), 2.78 (s, 4H), 3.70 (br.t, J = 4.2 Hz, 4H), 6.97-7.00 (t, J =
8.6 Hz, 2H), 7.32-7.40 (m, 2H).
7.
8.
N. Salam, S. K. Kundu, R. Ali Molla, P. Mondal, A. Bhaumik
and S. Manirul Islam, RSC Adv., 2014, 4, 47593-47604.
H. Naeimi and M. Moradian, Appl. Organometal. Chem. ,
2013, 27, 300–306.
Conclusions
9.
In summary,
a
novel catalyst has been developed by
10.
11.
12.
13.
H. Zhu, M. L. Du, M. L. Zou, C. S. Xu and Y. Q. Fu, Dalton
Trans., 2012, 41, 10465–10471.
Y. Zhang, J. Ouyang and H. Yang, Appl. Clay Scie., 2014, 95,
252–259.
P. Pasbakhsh and G. J. Churchman, Apple Academic Press,
2015.
P. Yuan, P. D. Southon, Z. Liu, M. E. R. Green, J. M. Hook,
S. J. Antill and C. J. Kepert, J. Phys. Chem. C 2008, 112,
15742–15751.
functionlization of HNTs with (3-chloropropyl) trimethoxysilan,
thiosemicarbazide and furfural and incorporation of copper species.
The utility of this catalyst for A3 and KA2 coupling reactions of
aldehydes and ketone, phenyl acetylene and amines for synthesis of
corresponding propargylamines under ultrasonic irradiation was
confirmed. Besides excellent catalytic activity, the catalyst was
reusable and could be recovered and reused up to four reaction
runs. Notably, the introduced functionality of the HNTs support
could effectively immobilize the copper species and suppress its
leaching. Broad substrate scope, simplicity of the procedure, the
green and environmentally benign nature of the protocol as well as
14.
M. Zou, M. Du, M. Zhang, T. Yang, H. Zhu, P. Wang and S.
Bao, Mater.Res.Bull., 2014, 61, 375–382.
16 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Please do not adjust margins
New Journal of Chemistry
Page 17 of 19
Journal Name
View Article Online
DOI: 10.1039/C7NJ02272G
ARTICLE
15.
16.
17.
T. Yang, M. Du, M. Zhang, H. Zhu, P. Wang and M. Zou,
Nanomater. Nanotech., 2015, 5, 1-9.
Y. Zhang, X. He, J. Ouyang and H. Yang, Sci. Rep. , 2013, 1-
6.
44.
45.
R. Mirsafaei, M. M. Heravi, S. Ahmadi, M. H. Moslemin
and T. Hosseinnejad, J. Mol. Catal. A Chem., 2015, 402,
100-108.
C. Lee, W. Yang and R. G. Parr, Phys. Rev. B., 1988, 37,
785.
M. Massaro, V. Schembri, V. Campisciano, G. Cavallaro, G.
Lazzara, S. Milioto, R. Noto, F. Parisi and S. Riela, RSC Adv., 46.
R. F. W. Bader, Oxford University Press: Oxford, UK, 1990.
J. Mondal, A. Modak, A. Dutta, S. Basu, S. Nath Jha, D.
Bhattacharyya and A. Bhaumik, Chem. Commun., 2012,
48, 8000–8002.
S. Mallik, S. S. Dash, K. M. Parida and B. K. Mohapatra, J.
Colloid Interface Sci., 2006, 300, 237–243.
S. Bordeepong, D. Bhongsuwan, T. Pungrassami and T.
Bhongsuwan, Songklanakarin J. Sci. Technol, 2011, 33,
599-607.
2016, 6, 55312-55318 .
47.
18.
19.
P. Yuan, A. Thill and F. Bergaya, Elsevier, 2016.
Y. Zhang and H. Yang, Phys. Chem. Miner., 2012, 39, 789-
795.
Y. Zhang, A. Tang, H. Yang and J. Ouyang, Appl Clay Sci.,
2016, 119, 8–17.
48.
49.
20.
21.
22.
23.
24.
S. Sadjadi and M. Eskandari, Ultrason. Sonochem., 2013,
20, 640–643.
R. S. Murali, M. Padaki, T. Matsuura, M. S. Abdullah and A. 50.
F. Ismail, Sep.Purif.Technol., 2014, 132, 187–194.
L. Zatta, J. E. F. da Costa Gardolinski and F. Wypych, Appl.
Clay Scie., 2011, 51, 165–169.
S. Kumar-Krishnan, A. Hernandez-Rangel, U. Pal, O.
Ceballos-Sanchez, F. J. Flores-Ruiz, E. Prokhorov, O. Arias
de Fuentes, R. Esparza and M. Meyyappan, J. Mater.
Chem. B, 2016, 4, 2553-2560.
I. Bottero, B. Bonelli, S. E. Ashbrook, P. A. Wright, W.
Zhou, M. Tagliabue, M. Armandi and E. Garrone, Phys.
Chem. Chem. Phys. , 2011, 13, 744-750.
L. Guimaraes, A. N. Enyashin, G. Seifert and H. A. Duarte,
J. Phys. Chem. C, 2010, 114, 11358-11363.
L. Guimarães, A. N. Enyashin, J. Frenzel, T. Heine, H. A.
Duarte and G. Seifert, Acs Nano, 2007, 1, 362-368.
Y. Zhao and D. G. Truhlar, J. Chem. Theory Comput. , 2008,
4, 1849-1868.
B. Szczepanik and P. Słomkiewicz, Appl Clay Sci., 2016,
124-125, 31–38.
51.
M. Massaro, C. G. Colletti, G. Lazzara, S. Guernelli, R. Noto
and S. Riela, ACS Sustainable Chem. Eng., 2017, 5, 3346–
3352.
52.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
D. Grabka, M. Raczyńska-Żak, K. Czech, P. M. Słomkiewicz
and M. A. Jóźwiak, Appl Clay Sci., 2015, 114, 321–329.
W. O. Yah, H. Xu, H. Soejima, W. Ma, Y. Lvov and A.
Takahara, J. Am. Chem. Soc., 2012, 134, 12134-12137.
F. Yu, H. Deng, H. Bai, Q. Zhang, K. Wang, F. Chen and Q.
Fu, ACS Appl. Mater. Interfaces, 2015, 7, 10178–10189.
M. C. Da Silva, E. C. Dos Santos, M. P. Lourenc¸o and H. A.
Duarte, J. Mol. Model., 2013, 19, 1995-2005.
R. Demichelis, Y. Noel, P. D’arco, L. Maschio, R. Orlando
and R. Dovesi, J. Mater. Chem. , 2010, 20, 10417–10425.
S. Sadjadi, M. M. Heravi and M. Daraie, Res. Chem.
Intermed., In press.
53.
54.
55.
56.
57.
P. J. Hay and W. R. Wadt, J. Chem. Phys. , 1985, 82, 284-
298.
M. W. Schmidt, K. K. Baldridge, J. A. Boatz, S. T. Elbert, M.
S. Gordon, J. H. Jensen, S. Koseki, N. Matsunaga, K. A.
Nguyen, S. Su, T. L. Windus, M. Dupuis and J. A.
Montgomery Jr, J. Comput. Chem. , 1993, 14, 1347-1363.
V. Barone and M. Cossi, J. Phys. Chem. A., 1998, 102,
1995-2001.
J. Mondal, A. Modak, A. Dutta and A. Bhaumik, Dalton
Trans., 2011, 40, 5228-5235.
R. G. A. Bone and R. F. W. Bader, J. Phys. Chem. , 1996,
100, 10892-10911.
R. F. W. Bader, Hamilton, McMaster University, 2000.
E. Espinosa, I. Alkorta, J. Elguero and E. Molins, J. Phys.
Chem., 2002, 117, 5529-5542.
S. B. Kumar, A. Solanki and S. Kundu, J. Mol. Struc., 2017,
1143, 163-167.
S. Dhar, M. Nethaji and A. R. Chakravarty, Inorg. Chim.
Acta., 2005, 358, 2437-2444.
P. A. Reddy, B. K. Santra, M. Nethaji and A. R. Chakravarty,
J. Inorg. Biochem., 2004, 98, 377-386.
S. Sadjadi, M. M. Heravi and M. Daraie, Res. Chem.
Intermed., 2016, In press.
M. Kidwai and A. Jahan, J. Iran. Chem. Soc. , 2011, 8, 462-
469.
S. Sadjadi, M. M. Heravi and M. Daraie, Res. Chem.
Intermed., 2017, 43, 2201–2214.
N. Hadian, S. Hakim, M. Nekoomanesh -Haghighi and N.
bahri-Laleh, Polyolefins. J., 2014, 1, 33-41.
S. Sadjadi, M. M. Heravi and M. Daraie, J. Mol. Liq. , 2017,
231, 98–105.
58.
59.
60.
61.
62.
S. Sadjadi, M. M. Heravi and D. M., Res. Chem. Intermed.,
2017, 43, 2201–2214.
T. Hossiennejad, M. Darai, M. M. Heravi and N. N.
Tajoddin, J. Inorg. Organomet. Polym. Mater. , 2017, In
press.
R. Mirsafaei, M. M. Heravi, S. Ahmadi, M. H. Moslemin
and T. Hosseinnejad, J.Mol.Cat., 2015, 402, 100–108.
M. M. Heravi, F. Mousavizadeh, N. Ghobadi and M.
Tajbakhsh, Tetrahedron Lett., 2014, 55, 1226–1228.
S. Sadjadi, S. Sadjadi and R. Hekmatshoar, Ultrason.
Sonochem., 2010, 17, 764–767.
63.
64.
65.
66.
38.
39.
40.
41.
42.
43.
B. K. Santra, P. A. N. Reddy, M. Nethaji and A. R.
Chakravarty, J. Chem. Soc., Dalton Trans., 2001, 0, 353-
3555.
H. Naeimi and R. Shaabani, Ultrason. Sonochem., 2017,
34, 246–254.
67.
68.
T. Baie Lashaki, H. A. Oskooie, T. Hosseinnejad and M. M.
Heravi, J. Coord. Chem. , 2017.
K. S. Suslick, D. A. Hammerton and R. E. Cline, J. Am.
Chem. Soc., 1986, 108, 5641-5642.
T. Hossiennejad, M. Daraie, M. M. Heravi and N. N.
Tajoddin, J. Inorg. Organomet. Polym. , 2017.
R. Mirsafaei, M. M. Heravi, T. Hosseinnejad and S.
Ahmadi, Appl. Organometal. Chem., 2016.
69.
70.
71.
72.
73.
T. J. Mason, Chem. Soc. Rev., 1997, 26, 443-451.
B. Banerjee, Ultrason. Sonochem., 2017, 35, 1-14.
B. Banerjee, Ultrason. Sonochem., 2017, 35, 15-35.
B. Banerjee, Aust. J. Chem., 2017, 70, 872-888.
B. Banerjee, J. Serb. Chem. Soc. , 2017.
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 17
Please do not adjust margins

Please do not adjust margins
New Journal of Chemistry
Page 18 of 19
View Article Online
DOI: 10.1039/C7NJ02272G
ARTICLE
74.
Journal Name
S. Sadjadi, M. Malmir and M. M. Heravi, RSC. Adv., 2017,
7, 36807-36818.
A. Elhampour, M. Malmir, E. Kowsari, F. Boorboor ajdari
and F. Nemati, RSC Adv., 2016, 6, 96623-96634.
M. S. Hosseini and F. Moeini, New J. Chem., 2014, 38, 624- 83.
635.
81.
82.
B. Sreedhar, P. R. Surendra, B. P. Veda and A. Ravindra,
Tet. Lett., 2005, 46 7019–7022.
Elhampour, A. Malmir, E. M. Kowsari, F. A. Boorboor and
F. Nemati, RSC Adv., 2016, 6, 96623-96634.
S. B. Park and H. Alper, Chem. Commun., 2005, 1315-
1317.
75.
76.
77.
M. Tajbaksh , M. Farhang, H. R. Mardani, R. Hosseinzadeh 84.
and Y. Sarrafi, Chin. J. Cat., 2013, 34, 2217-2222.
M. J. Albaladejo, F. Alonso, Y. Moglie and M. Yus, Eur. J.
Org. Chem., 2012, 2012, 3093-3104.
78.
L. Shi, Y.-Q. Tu, M. Wang, F.-M. Zhang and C.-A. Fan, Org.
Lett., 2004, 6, 1001-1003.
J. Safaei-Ghomi, M. A. Ghasemzadeh and A. Kakavand-
Qalenoei, J. Saudi Chem. Soc., 2016, 20, 502-509.
M. Tajbakhsh, M. Farhang, M. Baghbanian, H. R. and M.
Tajbakhsh, New J. Chem., 2015, 39, 1827-1839.
85.
F. Nador, M. A. Volpe, F. Alonso, A. Feldhoff, A. Kirschning
and G. Radivoy, Applied Catalysis A: General 2013, 455,
39-45.
79.
80.
18 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Page 19 of 19
New Journal of Chemistry
View Article Online
DOI: 10.1039/C7NJ02272G
Graphical abstract