Ultrasonic and bio-assisted synthesis of Ag@HNTs-T as a novel heterogeneous catalyst for the green synthesis of propargylamines: A combination of experimental and computational study

Article abstract of DOI:10.1002/aoc.4291

A novel heterogeneous catalyst is prepared through functionalization of halloysite nanotube with 1H-1,2,3-triazole-5-methanol and subsequent immobilization of silver nanoparticles through bio-assisted approach using Arctiumplatylepis extract. The resulting catalyst, Ag@HNTs-T, was characterized by using SEM/EDX, BET, XRD, FTIR, ICP-AES, TGA, DTGA and elemental mapping analysis. Moreover, we computationally assessed metal-ligand interactions in Ag@HNTs-T complex model to interpret the immobilization behavior of silver nanoparticles on HNTs surface via quantum chemistry computations. The catalytic activity of the catalyst was studied for the synthesis of propargylamines via A³ and KA² coupling reactions under ultrasonic irradiation. The results demonstrated that Ag@HNTs-T could efficiently promote these reactions to furnish the corresponding products in high yields and short reaction times. The study of the recyclability of the catalyst and Ag(0) leaching confirmed that the catalyst was recyclability up to four reaction runs with slight Ag(0) leaching.

Full text of DOI:10.1002/aoc.4291

Received: 14 October 2017
DOI: 10.1002/aoc.4291
Revised: 28 December 2017
Accepted: 29 December 2017
F U L L P A P E R
Ultrasonic and bio‐assisted synthesis of Ag@HNTs‐T as a
novel heterogeneous catalyst for the green synthesis of
propargylamines: A combination of experimental and
computational study
Masoumeh Malmir1 | Majid M. Heravi1
| Samahe Sadjadi2
| Tayebeh Hosseinnejad1
1 Department of Chemistry, School of
A novel heterogeneous catalyst is prepared through functionalization of
halloysite nanotube with 1H‐1,2,3‐triazole‐5‐methanol and subsequent immo-
bilization of silver nanoparticles through bio‐assisted approach using
Arctiumplatylepis extract. The resulting catalyst, Ag@HNTs‐T, was character-
ized by using SEM/EDX, BET, XRD, FTIR, ICP‐AES, TGA, DTGA and elemen-
tal mapping analysis. Moreover, we computationally assessed metal‐ligand
interactions in Ag@HNTs‐T complex model to interpret the immobilization
behavior of silver nanoparticles on HNTs surface via quantum chemistry com-
putations. The catalytic activity of the catalyst was studied for the synthesis of
propargylamines via A3 and KA2 coupling reactions under ultrasonic irradia-
tion. The results demonstrated that Ag@HNTs‐T could efficiently promote
these reactions to furnish the corresponding products in high yields and short
reaction times. The study of the recyclability of the catalyst and Ag(0) leaching
confirmed that the catalyst was recyclability up to four reaction runs with slight
Ag(0) leaching.
Science, Alzahra University, PO Box
1993891176 Vanak, Tehran, Iran
2 Gas Conversion Department, Faculty of
Petrochemicals, Iran Polymer and
Petrochemicals Institute, PO Box 14975‐
112, Tehran, Iran
Correspondence
Majid M. Heravi, Department of
Chemistry, School of Science, Alzahra
University, Vanak, Tehran, Iran, PO Box
1993891176.
Email: mmh1331@yahoo.com;
mmheravi@alzahra.ac.ir
KEYWORDS
A3 and KA2 coupling reactions, bio‐synthesis, DFT and PCM calculations, halloysite, silver
nanoparticles
1 | INTRODUCTION
of propargylamines, some issues such as using toxic sol-
vents, costly catalysts and reaction media, have been still
A3 and KA2 coupling reactions are three‐component reac-
tions of amines, acetylenes and aldehydes or ketones
respectively. These reactions precede through activation
of terminal alkyne C–H bond in the presence of a catalyst
such as Ni, Cu, Ir, Ag, Cu, Fe and Au‐based catalysts,[1–6]
followed by reaction with carbonyl and amine compounds
and lead to the formation of propargylamines, which are
important synthetic versatile intermediates with utility
for the preparation of complicated heterocycles and natu-
ral products.[1,7] Although these reactions are superior to
many previously reported protocols[1,8,9] for the synthesis
unsolved.
Halloysite nanotubes, HNTs, is a naturally occurring
phyllosilicate with Al: Si ratio of 1:1, similar to the platy
kaolinite and general formula of (Al2(OH)4Si2O5·2H2O).
Pristine HNTs, which can be found in regions such as
[10]
china, USA, France and New Zealand in large scale,
has tubular morphology with the external diameters vary-
ing between 30 to 190 nm, internal diameters ranging
between 10‐100 nm and length of about 100 nm to
4000 nm.[11,12] Recently, the use of HNTs in various
research fields including catalysis and photo
Appl Organometal Chem. 2018;e4291.
wileyonlinelibrary.com/journal/aoc
Copyright © 2018 John Wiley & Sons, Ltd.
1 of 16
https://doi.org/10.1002/aoc.4291

2 of 16
MALMIR ET AL.
catalysis,[13,14] waste treatment, polymeric matrices, sepa-
ration technology,[15] drug delivery,[13] nanomaterial and
optical, magnetic and electrical applications[16] has been
rapidly increased. Between several applications, the utility
of HNTs as a support for immobilization of the catalytic
species gained growing attention.[11] Recently, Riela,
Lazzara et al. have published an excellent review article
in 1H‐1,2,3‐triazole‐5‐methanol functionalized HNTs
silver complex model (Ag@HNTs‐T) using density func-
tional theory (DFT)[46] and polarized continuum
(PCM)[47] methods and more importantly we employed
our calculated results to interpret some of our experimen-
tal elucidations.
Motivated by the excellent catalytic performance of
HNTs and in attempt to further disclose the interactions
of HNT and the catalytically active species, herein, we
report design and synthesis of a novel catalyst, in
which HNTs was functionalized with 1H‐1,2,3‐triazole‐5‐
methanol and used as a support for the immobilization
of bio‐reduced silver nanoparticles. The catalytic activity
of the novel catalyst, Ag@HNTs‐T, was studied for pro-
moting A3 and KA2 coupling reactions via a green proto-
col, i.e., using ultrasonic irradiations in aqueous media
(Scheme 1). The recyclability of Ag@HNTs‐T and Ag(0)
leaching were also studied.
[10]
on the use of HNT as a support for developing
metal‐based catalysts. In recent advances in this topic,
surface functionalization of HNTs has been introduced
as a potent way to manipulate the properties of HNTs
and improve the immobilization of the catalytic species
such as metal nanoparticles.[10,17–22]
Following our attempt for disclosing efficient and eco‐
friendly protocols for the synthesis of chemicals through
applying novel heterogeneous catalysts,[23–25] we have
recently focused our attention on the functionalization
of HNTs with various functionalization agents and study-
ing the utility of functionalized HNTs as efficient support
for immobilization of catalytically active species such as
heteropolyacid[26,27] and ionic liquids.[28] The results of
our researches as well as other research groups[10] clearly
established that the functionality on the surface of HNTs
has a significant role in efficient immobilization and sup-
pressing the leaching of the catalytic species. To shed
more light to the interactions of HNT and the catalytic
species, we also exploited theoretical chemistry[29] and
proved that the number and nature of the heteroatoms
on the functionality crucially affect the interaction of cat-
alytic species with HNTs.
Based on our focus on combined experimental and
computational design of heterogeneous nanocatalysts
and their applications in organic reactions,[30,31] we have
recently analysed and reported metal‐ligand interactions
between metal nanoparticles and several amine function-
alized polymeric and silica bonded mesoporous supports
from the structural, electronic and thermochemical view-
points.[32–41] Regarding the importance of information
about the physicochemical properties of support surfaces
in their computational design and applications,[42–45] in
this research we investigated computationally the immo-
bilization behaviour of silver nanoparticles on 1H‐1,2,3‐
triazole‐5‐methanol functionalized HNTs surface. For
being more astute, we assessed metal‐ligand interactions
2 | EXPERIMENTAL
2.1 | Materials
Reagents and chemicals used for the synthesis of the cat-
alyst and investigation of its catalytic activity included
aliphatic and aromatic aldehydes, cyclic ketone, amines,
acetylenes, sodium azide, 3‐chloropropyltriethoxysilane,
AgNO3, HNTs, toluene, EtOH, chloroform and 1H‐
1,2,3‐triazole‐5‐methanol. The latter was provided from
china and other chemicals were purchased from Sigma‐
Aldrich.
The as‐prepared catalyst was successfully character-
ized by using various characterization techniques includ-
ing FTIR, XRD, SEM/EDX, TGA, DTGA, ICP‐AES and
BET. The FTIR spectra were recorded by using PERKIN‐
ELMER‐ Spectrum 65 instrument. Room temperature
powder X‐ray diffraction patterns were obtained by using
a Siemens, D5000. CuKα radiation from a sealed tube.
SEM/EDX images were provided by applying a Tescan
instrument, using Au‐coated samples and acceleration
voltage of 20 kV. The BET analyses were achieved by
BELSORP Mini II instrument. Prior to BET analyses, the
catalyst and pristine HNTs were degassed at 423 K for
3 h. All organic products were known and identified by
SCHEME 1 A3 and KA2 coupling
reactions

MALMIR ET AL.
3 of 16
comparing their melting points (measured by using the
capillary tube method with an electro thermal 9200 appa-
ratus) and FTIR spectra with authentic propargylamines.
For some selected propargylamines, 1HNMR and
13CNMR spectra were also provided to prove the forma-
tion of the desired products.
2.3 | Incorporation of 1H‐1,2,3‐triazole‐5‐
methanol: Synthesis of HNTs‐T (2)
To synthesis HNTs‐T,1H‐1,2,3‐triazole‐5‐methanol (0.5 g)
was introduced to a suspension of HNTs‐Cl (1 g in 50 ml
dried toluene) and reacted under reflux condition at
110 °C overnight. Upon completion of the reaction, the
cream product 2 was filtered, washed with dry toluene
three times and dried at 100 °C in oven overnight.
2.2 | Synthesis of Cl‐functionalized HNTs:
HNTs‐Cl (1)
2.4 | Preparation of Arctiumplatylepis
flowering plant extracts (3)
To prepare HNTs‐Cl, 4 ml of 3‐chloropropyltriethoxysilane
and 1.2 g of HNTs were mixed in 50 ml dry toluene. Then,
the obtained mixture was sonicated and homogenized
under ultrasonic irradiation of power 100 W. After half
an hour, the mixture was heated under reflux condition
at 110 °C overnight. Finally, the cream solid was filtered
off, washed for three times with dried toluene and dried
at 100 °C overnight.
Generally, the leaves of Arctiumplatylepis were collected
from Tehran city, Iran. First, the violet flower of
Arctiumplatylepis was washed with distilled water and
crushed in porcelain mortar into powder. The aqueous
Arctiumplatylepis extract was prepared by boiling 2 g of
powder with 100 ml distilled water for 60 min. The extract
FIGURE 1 Preparation of Ag@HNTs‐T catalyst

4 of 16
MALMIR ET AL.
was cooled to room temperature and filtered through fil-
ter paper. Then, the filtrate was collected and the extract
3 was used for the reduction of silver salt and synthesis
of Ag NPs.
stirring. After 12 h, the product 4 was collected, washed
with EtOH/H2O for three times and dried at 60 °C for
12 h. The general synthetic procedure of Ag@HNTs‐T is
illustrated in Figure 1.
2.5 | Reduction of Ag(II) to Ag(0) and
Loading of Ag nanoparticles on HNTs‐T:
Synthesis of Ag@HNTs‐T (4)
2.6 | Typical Procedure of A3 and KA2
Coupling Reactions
Synthesis and immobilization of Ag nanoparticles were
carried out through reaction of HNTs‐T (1 g) and aqueous
solution of AgNO3 (0.1 gin 20 ml of water) under vigorous
stirring at room temperature for 0.5 h followed by reduc-
tion of silver salt to the Ag(0) nanoparticles by using the
Arctiumplatylepis extract as a reducing and stabilizing
agent. In a typical procedure, the fresh extract (2 ml)
was dissolved in 20 mL water and then added into the
as‐prepared mixture of HNTs‐T and AgNO3 under
In the solution of aldehyde or ketone (1 mmol), alkyne
(1.1 mmol) and amine (1 mmol) in water (20 ml) as sol-
vent, 25 mg of Ag@HNTs‐T was added. The reaction mix-
ture was then sonicated for appropriate reaction time at
100 W and room temperature. After completion of the
reaction (monitored by TLC), the reaction mixture was
diluted with hot EtOH (15 ml) and the catalyst was
filtered off. The filtrate was then cooled to room
temperature to allow the products to precipitate. Finally,
FIGURE 2 The SEM images of Ag@HNTs‐T (A) and EDX image of Ag@HNTs‐T (B)

MALMIR ET AL.
5 of 16
the pure products were furnished by re‐crystallization
with EtOH.
the catalyst, are present in the EDX analysis. The immobi-
lization of silver nanoparticles can also be confirmed by
observation of Ag in EDX analysis.
To study the dispersion of Ag(0) nanoparticles on the
functionalized HNTs, elemental mapping analysis of
Ag@HNTs‐T was performed, Figure 3. As depicted in
Figure 3, silver nanoparticles are dispersed on the
HNTs‐T almost uniformly. Notably, C and N atoms exhib-
ited good dispersion, indicating that the surface of HNTs
was uniformly functionalized with organic moiety.
The XRD pattern of the catalyst is depicted in Figure 4
. As shown, the XRD pattern exhibited the characteristic
peaks of both Ag nanoparticles and HNT structure,
Figure 4. The peaks denoted as star are the characteristic
peaks of silver nanoparticle (JCPDS card no. 04‐0783) and
the speaks labeled as circle (at 2θ = 8°, 13°, 23°, 28°, 31°,
3 | RESULT AND DISCUSSION
3.1 | Characterization of Ag@HNTs‐T
catalyst
The morphology of the catalyst was studied by using SEM
analysis, Figure 2. It can be seen that the final catalyst
preserved the tubular morphology of the HNTs. However,
the short tubes packed together to form aggregates. The
compact morphology of the catalyst can be assigned to
the presence of the electrostatic interactions between the
organic functionalities and silver nanoparticles which
can get the particles closer and form the aggregates.
The EDX images of the Ag@HNTs‐T, Figure 2, clearly
exhibited the presence of Al, Si and O atoms which can be
representative of HNTs framework. Moreover, C and N
atoms, which can be attributed to the organic moiety of
58° and 67°) are indicative of HNTs structure (JCPDS No.
[11,48]
29‐1487).
This observation confirmed that HNTs
structure is preserved in Ag@HNTs‐T. Considering the
similarity of interlayer distances of pristine HNTs and
FIGURE 3 The elemental mapping analysis of the Ag@HNTs‐T

6 of 16
MALMIR ET AL.
FIGURE 4 The XRD pattern of
Ag@HNTs‐T
Ag@HNTs‐T, it can be concluded that the silver nanopar-
ticles were placed on the surface and the edges of the
HNTs tubes. This is in good agreement with previous
reports.[11]
be assigned to the C=N overlapped with the characteristic
bands of HNT are clearly observable. In addition to the
FTIR data, incorporating of organic functionalities were
confirmed by using other characterization methods such
as EDX.
To calculate the content of Ag(0) nanoparticles in the
catalyst, ICP‐AES analysis was applied. Prior to the anal-
ysis, the digestion of Ag@HNTs‐T was accomplished by
using concentrated HCl and HNO3 solution. ICP‐AES
analysis of the resulting extract established that the con-
tent of silver nanoparticles was 5 %w/w.
To further confirm the formation of the catalyst, FTIR
spectra of pristine HNTs, Ag@HNTs‐T and HNTs‐T were
recorded and compared, Figure 5. As depicted in Figure 5
the FTIR spectra are almost similar and in three of them
the characteristic bands of HNT, i.e. the bands at
3692 cm‐1 and 3618 cm‐1, which are representative of
internal hydroxyl groups of HNTs and the band at
672 cm‐1 1029 cm‐1 that are indicative of Al‐O‐Si vibration
and Si–O stretching as well as the band at 1620 cm‐1 (the
bending of OH groups on interstitial water) and 2905 cm‐1
can be observed. In the FTIR spectra of Ag@HNTs‐T and
HNTs‐T, the characteristic bands of the organic function-
alities, i.e. the band at 2905 cm‐1 which can be assigned to
the –CH2 stretching and the band at 1620 cm‐1 which can
Nitrogen
adsorption–desorption
isotherm
of
Ag@HNTs‐T is illustrated in Figure 6. As depicted, the
shape of the isotherm of Ag@HNTs‐T is of type II nitro-
gen adsorption–desorption isotherm with H3 hysteresis
loops,[11,27] indicating the porous entity of the catalyst.
To provide more insight into the textural properties of
the catalyst and elucidate how functionalization of HNTs
FIGURE 5 The FTIR spectrum of
pristine HNTs (a), Ag@HNTs‐T catalyst
(b) and HNTs‐T (c)

MALMIR ET AL.
7 of 16
FIGURE 7 The TGA (a) and DTGA (b) analysis of Ag@HNTs
nanocatalyst,[32–35] copper (I) and (II) ‐aminated
KIT‐5[37,40] and N‐sulfamic‐aminated KIT‐5 catalysts.[39]
Armed with these experiences, we present a quantitative
model for description of immobilization behavior of Ag
NPs on functionalized HNTs support via DFT[46,49] and
PCM[47] computational approaches.
In this content, metal‐ligand interactions in 1H‐1,2,3‐
triazole‐5‐methanol functionalized HNTs‐supported Ag
complex (denoted as Ag@HNTs‐T) was investigated from
the structural and electronic viewpoints in the gas and
two solution phases.
In this respect, we first designed an effective structural
model for HNTs‐T ligand as 1:1 layered alumino silicates
and its complex with silver NPs, (displayed in Scheme 1).
In the illustrated coordination mode, Ag coordinates to
nitrogen of 1,2,3‐triazole ring and concurrently can coor-
dinates to oxygen of hydroxyl functional group. It is
important to mention that we have shown in our previous
research that this size of structural model for an alumino
silica supported catalyst has a reliable comport between
accuracy and time saving efficiency of computational
procedure.
In Figure 8, we have displayed the optimized geome-
tries of HNTs‐T ligand and Ag@HNTs‐T complex calcu-
lated at M06‐2X/6‐311G** level of theory[50] together
with the calculated values of bond order and bond length
for Ag‐N and Ag‐O interactions. It is worthwhile to note
that M06‐2X has been introduced as a Global hybrid func-
tional with intermediate HF exchange contribution. It is
also the top performer within the 06 functional for main
group thermochemistry, kinetics and non‐covalent inter-
actions. The harmonic frequency analysis was applied to
confirm that the found structures correspond to minima.
FIGURE 6 N2 adsorption‐desorption isotherms of Ag@HNTs‐T
with 1H‐1,2,3‐triazole‐5‐methanol and immobilization of
silver nanoparticles affect the textural features of pristine
HNTs, total pore volume, average pore diameter and sur-
face area of the catalyst were compared with those of pris-
tine HNTs, Table 1. As tabulated in Table 1, upon
functionalization of HNTs and incorporation of Ag(0)
nanoparticles, the surface area decreased compared to
pristine HNTs while, the average pore diameter increased.
Furthermore, the total pore volume slightly reduced.
According to the previous reports, the decrease in the sur-
face area can be attributed to the surface functionalization
of HNTs.[27]
Ag@HNTs‐T was also subjected to TGA and DTGA
analyses. The results of thermal analysis over the range
of 35‐550 °C, Figure 7, demonstrated that two main degra-
dation occurred over this range. First, the degradation
about 200 °C, which can be due to loss of water and sec-
ond one, about 450 °C, which can be assigned to the loss
of organic functional group. Notably, the content of the
functionality was estimated to be about 10 % w/w.
3.2 | Computational section
As it was discussed earlier, we have recently focused
on the joint experimental and computational assessment
of heterogeneous catalysts including modified poly
(styrene‐co‐maleic anhydride) palladium and copper
TABLE 1 Textural property of the Ag@HNTs‐T
Catalyst
SBET (m2 g‐1)
Total pore volume (cm3 g‐1)
Average pore diameter (nm)
Ag@HNTs‐T
36.2
0.19
0.2
21.4
HNTs
51
15

8 of 16
MALMIR ET AL.
FIGURE 8 The energy‐minimized
structure of HNTs‐T ligand and
Ag@HNTs‐T complex together with the
calculated Ag‐O and Ag‐N bond orders
(bond lengths) obtained at M06‐2X/6‐
311G** level of theory
TABLE 2 The calculated values of some selected bond orders
(bond lengths) in HNTs‐T ligand and Ag@HNTs‐T complex
obtained at M06‐2X/6‐311G** level of theory. Note that numbering
of atoms is in accordance with Figure 8
In the case of silver atom, LANL2TZ effective core poten-
tials (ECPs) were used together with the accompanying
basis sets to describe the valence electron density.[51]
Moreover, the solvent effects have been examined from
the electronic viewpoint on the basis of a continuum rep-
resentation of solvent surrounding the substances via
polarized continuum model.[47] All DFT computations
have been performed using GAMESS suite of programs.[52]
To evaluate the variation of bond orders via coordina-
tion, we have calculated the bond order and bond length
of some key bonds in HNTs‐T ligand with their correspond-
ing bonds in Ag@HNTs‐T which have been listed in Table 2.
The reported results of Table 2 demonstrate that the
calculated values of bond order of C‐OH and C‐N1
HNTs‐T ligand
Ag@HNTs‐T complex
C‐OH
C‐N1
O‐H
1.084 (135.2 pm)
0.835 (142.5 pm)
1.339 (135.4 pm)
0.939 (96.2 pm)
0.985 (154.1 pm)
0.888 (97.4 pm)
decrease from 1.08 and 1.33 in HNTs‐T ligand to 0.83
and 0.98 in Ag@HNTs‐T complex indication the coordina-
tion of 1H‐1,2,3‐triazole‐5‐methanol species to the metal.
This behavior can be mainly ascribed to the donation of

MALMIR ET AL.
9 of 16
shared electrons from this chemical bond to silver atom
through the complexation that is further supported with
our FT‐IR spectroscopic observations. Moreover, compari-
son of the calculated bond order values of Ag‐N and Ag‐O
in Ag@HNTs‐T complex reveals that interaction of silver
atom with nitrogen is stronger than the interaction of
silver atom with oxygen (0.253 and 0.192 for Ag‐N and
Ag‐O in Ag@HNTs‐T complex, respectively.
Precisely speaking, the main bands of the Ag@HNTs‐T
appeared at 3692 and 3618 cm‐1 were attributed to O‐H and
N‐H stretching, 1620 cm‐1 was assigned to C‐N stretching
and 1365 cm‐1 was assigned to C‐O stretching. Compara-
tively, the FT‐IR spectrum of HNTs‐T also shows the main
bands around 3692 and 3618 cm‐1 assigned to O‐H and
N‐H stretching, respectively (as displayed in Figure 5).
More importantly, the band at 1637 cm‐1 attributed to the
stretching vibration of the C‐N groups has been shifted to
1620 cm‐1 in the Ag@HNTs‐T which can be mainly associ-
ated with Ag‐HNTs‐T interaction. Furthermore, FT‐IR
spectrum of HNTs‐T exhibited a typical band at 1374 cm‐1
corresponding to the stretching mode of C‐O which shifts
to the smaller wave numbers (1365 cm‐1) after immobili-
zation of Ag NPs in Ag@HNTs‐T. Worthy to mention
that the similar comparative interpretations between
FT‐IR bands and calculated metal‐ligand interactions
are generally considered and reported, previously.[53–56]
In Table 3, we have presented comparatively M06‐2X/
6‐311G**calculated bond orders of Ag‐N and Ag‐O chemi-
cal bonds in the presence of water and toluene as solvents.
As it can be seen in Table 3, Ag‐N and Ag‐O bond orders in
Ag@HNTs‐T complex has larger calculated values in water
solution compared with those obtained in toluene which
corroborate the more efficiency of water as solvent rather
than toluene. It should be mentioned that effective immo-
bilization and smaller size of silver NPs on functionalized
FIGURE 9 Frontier molecular orbital of Ag@HNTs‐T complex
obtained at M06‐2X/6‐311G** level of theory
between filled non‐bonding orbitals (HOMO) on N and O
atoms and an empty dσ orbital (LUMO) on metal atom.
On the basis of these electronic and structural features
of Ag@HNTs‐T complex, it can be claimed that silver NPs
are immobilized on functionalized HNTs majorly at nitro-
gen of triazole ring sites in the presence of water as pre-
ferred solvent.
HNTs have been elucidated in water solution in compari-
[57,58]
son with toluene.
Finally, we have presented
the Highest Occupied Molecular Orbital (HOMO) and
the Lowest Unoccupied Molecular Orbital (LUMO) of
Ag@HNTs‐T complex calculated at M06‐2X/6‐311G** level
of theory (displayed in Figure 9). As we expect from the
typical organometallic frontier molecular orbital (FMO)
theory,[59] silver neutral atom primarily coordinates to
nitrogen and oxygen of ligand through interactions
3.3 | Catalytic activity investigation
In the next step, the catalytic activity of Ag@HNTs‐T was
investigated. In this line, synthesis of propargylamines
through three‐component reaction of aldehydes or ketones,
amines and acetylenes, A3 and KA2 coupling reactions was
selected as a chemical transformation. The reason behind
this choice was the importance of propargylamines as
key intermediates for the synthesis of diverse range of
organic compounds with utility for drug industry.
Initially, the reaction of phenyl acetylene, benzalde-
hyde and morpholine was selected as a model reaction
and performed in the presence and absence of the catalyst.
It was found that no product was furnished in the absence
of the catalyst, indicating the necessity of use of the catalyst
TABLE 3 The obtained values of Ag‐O and Ag‐N bond orders in
Ag@HNTs‐T complex complex in water and toluene solution
phases, calculated at M06‐2X/6‐311G** level of theory via PCM
approach
Water
Toluene
Ag‐O
Ag‐N
0.179
0.158
0.238
0.210

10 of 16
MALMIR ET AL.
for promoting this reaction. Next, the utility of ultrasonic
irradiation for developing an efficient and rapid protocol
for this transformation was studied. To this purpose, the
model reaction in the presence of 25 mg (1 mol%) of the
catalyst was performed in aqueous media under ultrasonic
irradiation. The results established that ultrasonic irradia-
tion could promote the reaction rapidly to furnish the
desired product in high yield. Notably, the comparison of
the efficiency of ultrasonic irradiation with conventional
procedures including reflux and stirring condition, proved
the superior performance of the former. According to the
previous reports, the effect of ultrasonic irradiation can
be explained based on the cavitation effect. In other word,
ultrasonic irradiation can induce generation, growth and
collapse of cavities which can result in the formation of
spots with high pressure and temperature.[60]
Confirming the efficiency of the ultrasonic irradiation,
the reaction variables including the catalyst amount, reac-
tion solvent and the power of ultrasonic irradiation were
optimized by varying these values and studying their effect
on the yield of the desired product, Figure 10. As shown in
Figure 10, among various solvents used examined for this
reaction (toluene, water, ethanol and chloroform), use of
water as a solvent resulted in the highest yield of the prod-
uct. It is also clear that the amount of the catalyst could
affect the yield of the desired product. Increasing the
amount of the catalyst from 15 to 25 mg significantly
improved the yield of the product. However, more increase
of this value to 35 mg exerted different effects depending
on the ultrasonic power. As obvious in Figure 8, in the case
of using ultrasonic power of 120 W increase of the catalyst
amount to 35 mg had no effect on the yield of the product
while, in the case of using ultrasonic power of 50 W and
100 W, the increase in the catalyst amount led to the
increase and decrease of the product yield respectively.
Regarding the ultrasonic power, it was found that increas-
ing the power of ultrasonic irradiation from 50 to 100 W
positively affected the yield of the product, while further
increase of this value had detrimental effect on the yield
of the product. This observation can be attributed to the
promotion of various side‐reactions and formation of by‐
products as confirmed by GC‐MSS analysis. Considering
all discussed results, the optimum reaction condition was
selected as use of 25 mg of the catalyst, water as solvent
and ultrasonic of power 100 W.
Armed with the optimum reaction condition, the gen-
erality of this protocol was examined by using various
substrates with different steric and electronic properties,
Table 4. As tabulated in Table 4, all reactions could be
proceed in relatively short reaction times (15‐40 min) to
afford the corresponding products in high yields. Notably,
A3 coupling reactions were more facile compared to the
KA2 reactions and led to the slightly higher yields in
shorter reaction times.
Although the main aim of this research was disclos-
ing the utility of HNTs for developing a novel heteroge-
neous Ag(0) catalyst and synthesis of propargylamines
was selected as a model chemical transformation to
establish the catalytic utility of this catalyst, the out-
standing efficiency of Ag@HNTs‐T, motivated us to
study whether using this catalyst under ultrasonic irradi-
ation can be considered as an efficient methodology for
these organic reactions. To this purpose, the efficiency
of this protocol for the synthesis of the model product
was compared with those of Ag NPs, Ag@HNTs and
some of previously reported ones (Table 5). Compared
to many previously reported catalysts, Table 5, such as
AgI‐Pc‐L, Ag‐CIN‐1, sulfonate‐based Cu(I) metal‐organic
frameworks, Cu(I)MOF, Cu2O/nano‐CuFe2O4, ZnS,
ZnO nano particles and immobilized silver on the
FIGURE 10 Effects of loading of
catalyst, duration of reaction and solvent
for the synthesis of propargylamine

MALMIR ET AL.
11 of 16
TABLE 4 Synthesis of three‐component reaction of derivatives aldehyde or cyclic ketone, secondary‐ amines and terminal alkynes cata-
lyzed by Ag@HNTs‐Ta [1,61–66]
R1
R2
R3
R4
R5
Product
6a
Time (min)
Yieldb (%)
1a: C6H5
H
4a: ‐(CH2)5‐
5a: C6H5
20
90
1b: p‐Cl‐C6H4
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
H
H
H
H
H
H
H
H
H
4a
4a
4a
4a
4a
4a
4a
4a
4a
4a
5a
6b
6c
18
20
22
15
15
20
15
18
22
27
17
20
22
19
17
20
30
30
20
22
20
15
20
22
20
28
18
27
19
20
25
20
17
25
18
30
35
37
35
91
93
89
90
90
83
93
92
94
85
95
88
82
90
88
89
90
92
93
80
92
90
85
90
92
82
92
80
90
84
80
90
85
86
83
80
88
90
92
1c: p‐NO2‐C6H4
5a
1d: p‐Me‐C6H4
5a
6d
6e
6f
1e:p‐MeO‐C6H4
5a
1f:o‐OH‐C6H4
5a
1 g:Furfuryl
5a
6 g
6 h
6i
1 h: p‐OHCC6H4
5a
1i: o‐Naphthyl
5a
1a
5b:p‐CH3‐C6H4
6j
1a
5c:p‐F‐C6H4
6 k
6 l
6 m
6n
6o
6p
6q
6r
1a
4b:‐(CH2)2‐O‐(CH2)2‐
5a
5a
5a
5a
5a
5a
5a
5a
5b
5a
5a
5a
5b
5a
5a
5a
5a
5b
5a
5a
5a
5a
5a
5a
5a
5a
5a
5a
5a
1b
4b
1c
4b
1d
4b
1e
4b
1f
4b
1 g
4b
1j: m‐NO2‐C6H4
4b
6 s
6 t
6u
6v
7a
7b
7c
1a
4b
1a
4c: ‐(CH2)4‐
1a
4d:C2H5
4a
C2H5
2ac: H
2a
4a
2a
4b
4c
2a
7d
7e
7f
2a
4d
4a
2b: C6H11
2b
4b
4b
4c
7 g
7 h
7i
2b
2b
2b
4d
4a
7j
2c: ‐(CH2)2‐Me
7 l
7 m
7n
7o
8a
8b
8c
2c
4b
4c
2c
2c
4d
4a
3a: ‐(CH2)4‐
3a
4b
4c
3a
3b: ‐(CH2)5‐
4a
8d
(Continues)

12 of 16
MALMIR ET AL.
TABLE 4 (Continued)
R1
3b
3b
3b
3b
3b
R2
R3
4a
4b
4b
4b
4c
R4
R5
5b
5a
5b
5c
5a
Product
Time (min)
Yieldb (%)
8e
8f
40
40
40
35
30
85
88
80
82
88
8 g
8 h
8i
aReaction conditions: arylaldehydes1a‐j (1 mmol) or aliphatic aldehyde 2a‐c (1 mmol) or aliphatic ketone 3a, b(1 mmol), amines 4a‐d (1 mmol), alkynes 5a‐c
(1.1 mmol), H2O (20 ml) and Ag@HNTs‐T (0.025 g or 1 mol%) under ultrasonic irradiation (100 W) at room temperature.
bIsolated yield.
cAqueous formaldehyde (37%, 0.4 ml).
TABLE 5 Comparison of Ag@HNTs‐T with other recently reported metal catalysts for the synthesis of propargylaminea
Reaction
conditions
Time Catalyst
(min) amount
Yieldb
(%)
Entry Catalyst
Ref
1
Ag@HNTs‐T
H2O / r.t./US
S.F./ 90 °C
17
25 mg (1 mol%) 95
This work
[66]
2
h‐Fe2O3@DA/Ag
60
10 mg
96
97
89
89
65
59
91
89
87
95
93
90
95
95
40
75
[23]
[67]
[68]
[4]
3
h‐Fe2O3@SiO2‐CD/Ag
H2O/ r.t./ US
Stirrer/ 90 °C
Reflux/ H2O
H2O/ 40 °C
8
20 mg
4
ZnO nano particles
120
240
720
10 mol%
10 mol%
5 mg
5
Immobilized Silver on Surface‐modified ZnO NPs
Ag‐CIN‐1c
AgI‐Pc‐Ld
6
[69]
[70]
[71]
[72]
[73]
[74]
[72]
[29]
[27]
7
Toluene/MW/ 150 °C 20
3 mol%
0.5 mol%
10 mol%
20 mg
8
CuNPs/TiO2
Neat/ 70 °C
420
9
ZnS
Reflux/ CH3CN
Reflux/EtOH, 90 °C
270
1440
90
10
11
12
13
14
15
16
17
sulfonate‐based Cu(I) metal‐organic frameworks
CuI catalysts supported on protonated trititanate nanotubes Solvent‐free, 70 °C
20 mg
Cu2O/nano‐CuFe2O4
Cu(I)MOF
Solvent‐free, 90 °C
Neat/ 80 °C
40
10 mg
60
2.5 mol%
30 mg
CuI@HNTs‐2 N
Cu@Fur‐SBA‐15
Ag
EtOH/ r.t./ US
Solvent‐free/ r.t.
H2O / r.t./US
10
15
0.5 mol%
25 mg
17
This work
This work
Ag@HNTs
H2O / r.t./US
17
25 mg
aReaction conditions: morpholine (1 mmol), benzaldehyde (1 mmol), phenylacetylene (1.1 mmol) in the presence of different conditions.
bIsolated yield.
cAg‐grafted covalent imine network material.
dAg(I)(Pyridine‐Containing Ligand) Complexes.
eCu(II) immobilized on aminatedepichlorohydrin activated silica.
fbenzylated MCM‐41 solfunic acid.
surface‐modified ZnO nanoparticles, Ag@HNTs‐T exhib-
ited superior catalytic activity and furnished the desired
product in higher yields. Some other catalysts such as
Cu@Fur‐SBA‐15, CuI@HNTs‐2 N, CuI catalysts sup-
ported on protonated trititanate nanotubes, h‐
Fe2O3@DA/Ag, however, exhibited comparative or
slightly higher catalytic activity compared to
Ag@HNTs‐T.
Comparison of the efficiency of Ag@HNTs‐T with
those of Ag NPs, Ag@HNTs proved the higher catalytic
activity of the former. According to the previous reports,
the role of HNT can be described in terms of improvement

MALMIR ET AL.
13 of 16
of the distribution of Ag nanoparticles and reducing their
sizes.[10]
On the other hand, the functionalities on the surface
of HNTs plays an important role in anchoring Ag(0)
nanoparticles and reducing the leaching (as the ICP
results confirmed).
are depicted in Figure 11. As shown in Figure 11, the cat-
alyst could be recovered and recycled for ten reaction runs
with slight loss of the catalytic activity, observed. Notably,
recycling of the catalyst for ten reactions run led to the
significant decrease in the yield of the product of model
reaction (the product was obtained in 78% yield).
To investigate the reason behind this observation, the
leaching of silver nanoparticles was studied by using ICP‐
AES. The obtained results indicated the heterogeneous
nature of the catalyst. The results demonstrated that the
leaching of Ag(0) nanoparticles for the recycled catalyst
for ten reactions run was only 0.0032 %w/w, while this
value for the recycled catalyst for tenth reaction run was
significant.
3.4 | Reaction mechanism
The plausible reaction mechanism for the synthesis of
propargylamines is depicted in Scheme 2. According to
the previous reports[63,66] the reaction initiated by the acti-
vation of the terminal C‐H bond of acetylene by silver
nanoparticles immobilized on the functionalized HNT
and production of an intermediate. The latter then reacted
with imnium ion obtained from the condensation reac-
tion of aldehyde or ketone and amine to furnish the corre-
sponding propargylamine derivative and Ag@HNTs‐T
catalyst.
3.6 | Spectral data for some selected
compounds, supporting information
3.6.1 | 1‐(1,3‐diphenylprop‐2‐ynyl)piperi-
dine (Table 4, 6a)
3.5 | Recyclability of the catalyst
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).
Considering the importance of the recyclability of the het-
erogeneous catalyst from the industrial and economical
points of view and to elucidate whether the immobiliza-
tion of silver nanoparticles was efficiently carried out on
the functionalized HNTs, the recyclability of Ag@HNTs‐
T was investigated for ten cycles. To the purpose, the yield
of the model product in the presence of the fresh
Ag@HNTs‐T was compared with those of recycled cata-
lysts. In this line, the recovered catalyst was washed with
EtOH, dried at 100 °C for 8 h and recycled for consecutive
reaction runs. The results of the recyclability experiments
3.6.2 | 1‐(3‐phenyl‐1‐(4‐(3‐phenyl‐1‐
(piperidin‐1‐yl)prop‐2‐ynyl)phenyl)prop‐2‐
ynyl)piperidine (Table 4, 6 h)
White solid; mp 157‐159 °C (Lit.[66] 158‐160 °C); 1H NMR
(400 MHz, CDCl3, ppm) δ 1.47 (m, 2H), 1.59‐1.63 (m, 4H),
SCHEME 2 The plausible mechanism for the synthesis of propargylamine under the Ag@HNTs‐T catalysis

14 of 16
MALMIR ET AL.
FIGURE 11 The recyclability of the
catalyst
2.59 (m, 4H), 4.81 (s, 1H), 7.33‐7.35 (m, 3H), 7.52‐7.55 (m,
(100 MHz, CDCl3, ppm) δ 24.9, 26.9, 27.1, 28.3, 32.7, 33,
2H), 7.63 (s, 2H).
42.9, 51.1, 61.1, 86.1, 88.9, 125.9, 128.9, 129.8, 132.6.
3.6.3 | 1‐(1‐(naphthalen‐3‐yl)‐3‐
phenylprop‐2‐ynyl)piperidine (Table 4, 6i)
3.6.7 | 4‐(1‐phenylhex‐1‐yn‐3‐yl)
morpholine (Table 4, 7 m)
1
1
Yellow oil; H NMR (400 MHz, CDCl3, ppm): δ 1.47‐1.51
Yellow oil; H NMR (400 MHz, DMSO‐d6, ppm) δ 0.97
(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.
(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).
3.6.8 | 4‐(1‐(2‐phenylethynyl)cyclohexyl)
morpholine (Table 2, 8f)
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.
3.6.4 | N,N‐diethyl‐1,3‐diphenylprop‐2‐yn‐
1‐amine (Table 4, 6v)
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).
3.6.5 | 4‐(3‐phenylprop‐2‐ynyl)morpholine
3.6.9 | 4‐(1‐((4‐fluorophenyl)ethynyl)
(Table 4, 7c)
cyclohexyl)morpholine (Table 4, 8 h)
1
Yellow oil; H NMR (400 MHz, CDCl3, ppm) δ 2.64‐2,67
Yellow oil; 1H NMR (400 MHz, DMSO‐d6, ppm) δ 1.26‐1.34
(m, 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).
(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).
3.6.6 | 1‐(1‐cyclohexyl‐3‐phenylprop‐2‐
ynyl)pyrrolidine (Table 4, 7i)
4 | CONCLUSION
Colorless liquid; 1H NMR (400 MHz, CDCl3, ppm) δ 1.05‐
1.36 (m, 5H), 1.56‐1.63 (m, 2H), 1.75‐1.79 (m, 6H), 1.82‐
2.10 (m, 4H), 2.5‐2.98 (m, 4H), 3.36‐3.38 (d, J =7.6 Hz,
1H), 7.14‐7.33 (m, 3H), 7.50‐7.63 (m, 2H). 13C NMR
In summary, HNTs was successfully functionalized with
1H‐1,2,3‐triazole‐5‐methanol and used as a support for
immobilization of silver nanoparticles and developing a

MALMIR ET AL.
15 of 16
[13] Y. Zhang, H. Yang, Phys. Chem. Miner. 2012, 39, 789.
novel catalyst, Ag@HNTs‐T. The reduction of silver salt
and capping of Ag(0) nanoparticles were achieved by
using a bio‐assisted approach using Arctiumplatylepis
extract. The catalytic activity of the catalyst was examined
for A3 and KA2 coupling reactions. The results established
that Ag@HNTs‐T could efficiently promote these reac-
tions under ultrasonic irradiation to furnish the corre-
sponding products in high yields. Noteworthy, the
catalyst was recyclable up to ten reaction runs and the sil-
ver leaching was dramatically suppressed. Moreover, our
DFT and PCM computational results are in confirmation
with the experimental observations for the nanocatalyst
from the structural and electronic viewpoints.
[14] Y. Zhang, J. Ouyang, H. Yang, Appl. Clay Scie. 2014, 95, 252.
[15] R. S. Murali, M. Padaki, T. Matsuura, M. S. Abdullah, A. F.
Ismail, Sep.Purif.Technol. 2014, 132, 187.
[16] Y. Zhang, A. Tang, H. Yang, J. Ouyang, Appl. Clay Sci. 2016,
119, 8.
[17] M. Massaro, V. Schembri, V. Campisciano, G. Cavallaro, G.
Lazzara, S. Milioto, R. Noto, F. Parisi, S. Riela, RSC Adv. 2016,
6, 55312.
[18] M. Massaro, S. Riela, G. Cavallaro, C. G. Colletti, S. Milioto, R.
Noto, F. Parisi, G. Lazzara, J. Mol. Catal. A. 2015, 408, 12.
[19] M. Massaro, S. Riela, G. Lazzara, M. Gruttadauria, S. Milioto, R.
Noto, Appl. Organomet. Chem. 2014, 28, 234.
[20] V. A. Vinokurov, A. V. Stavitskaya, Y. A. Chudakov, E. V.
Ivanov, L. K. Shrestha, K. Ariga, Y. A. Darrat, Y. M. Lvov, Sci.
Technol. Adv. Mater. 2017, 18, 147.
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 (INSF) for the given individual research
chair.
[21] S. Battistoni, A. Dimonte, E. Ubaldi, Y. Lvov, V. Erokhin,
J. Nanosci. Nanotechnol. 2017, 17, 5310.
[22] R. Noto, S. Milioto, G. Lazzara, M. Massaro, S. Riela, J. Mater.
Chem. B 2017, 5, 2867.
[23] S. Sadjadi, M. Malmir, M. M. Heravi, RSC Adv. 2017, 7, 36807.
[24] S. Sadjadi, M. M. Heravi, RSC Adv. 2016, 6, 88588.
ORCID
[25] S. Sadjadi, M. M. Heravi, M. Daraie, J. Mol. Liq. 2017, 231, 98.
[26] S. Sadjadi, M. M. Heravi, Res. Chem. Intermed. 2017, 43, 2201.
[27] S. Sadjadi, M. M. Heravi, RSC Adv. 2017, 7, 30815.
Majid M. Heravi http://orcid.org/0000-0003-2978-1157
Samahe Sadjadi http://orcid.org/0000-0002-6884-4328
[28] S. Sadjadi, M. M. Heravib, M. Malmir, B. Masoumi, Appl.
Organomet. Chem. .
REFERENCES
[29] S. Sadjadi, N. Bahri‐Laleh, J. Porous Mater. 2017, In press.
[1] S. V. Katkar, R. V. Jayaram, RSC Adv. 2014, 4, 47958.
[30] M. M. Heravi, M. Tamimi, H. Yahyavi, T. Hosseinnejad, Curr.
Org. Chem. 2016, 20, 1591.
[2] B. J. Borah, S. J. Borah, K. L. Saikia, D. K. Dutta, Catal. Sci.
Technol. 2014, 4, 4001.
[31] T. Hosseinnejad, B. Fattahi, M. M. Heravi, J. Mol. Modeling
2015, 21, 264.
[3] T. Zeng, W.‐W. Chen, C. M. Cirtiu, A. Moores, G. Song, C.‐J. Li,
Green Chem. 2010, 12, 570.
[32] F. Ebrahimpour‐Malamir, T. Hosseinnejad, R. Mirsafaei, M. M.
Heravi, Appl. Organomet. Chem. 2017, e3913.
[4] N. Salam, S. K. Kundu, R. Ali Molla, P. Mondal, A. Bhaumik, S.
Manirul Islam, RSC Adv. 2014, 4, 47593.
[33] T. Baie Lashaki, H. A. Oskooie, T. Hosseinnejad, M. M. Heravi,
[5] H. Naeimi, M. Moradian, Appl. Organometal. Chem. 2013,
27, 300.
J. Coord. Chem. 2017, 70, 1815.
[34] T. Hossiennejad, M. Daraie, M. M. Heravi, N. N. Tajoddin,
[6] N. Salam, S. K. Kundu, A. Singha Roy, P. Mondal, S. Roy, A.
J. Inorg. Organomet. Polym. 2017, 27, 861.
Bhaumik, S. Manirul Islam, Catal. Sci. Technol. 2013, 3, 3303.
[35] M. M. Heravi, T. Hosseinnejad, N. Nazari, Can. J. Chem. 2017,
95, 530.
[7] G. Villaverde, A. Corma, M. Iglesias, F. Sanchez, ACS Catal.
2012, 2, 399.
[36] T. Hosseinnejad, T. Kazemi, Mol. Cryst. Liq. Cryst. 2016, 637, 53.
[8] L. F. Bobadilla, T. Blasco, J. A. Odriozola, Phys. Chem. Chem.
Phys. 2013, 15, 16927.
[37] R. Mirsafaei, M. M. Heravi, T. Hosseinnejad, S. Ahmadi, Appl.
Organomet. Chem. 2016, 30, 823.
[9] M. Hosseini‐Sarvari, F. Moeini, New J. Chem. 2014, 38, 624.
[38] V. Zadsirjan, M. M. Heravi, M. Tajbakhsh, H. A. Oskooie, M.
[10] M. Massaro, C. G. Colletti, G. Lazzara, S. Milioto, R. Noto, S.
Shiri, T. Hosseinnejad, Res. Chem. Inter. 2016, 42, 6407.
Riela, J. Mater. Chem. A 2017, 5, 13276.
[39] R. Mirsafaei, M. M. Heravi, S. Ahmadi, T. Hosseinnejad, Chem.
Pap. 2016, 70, 418.
[11] P. Yuan, P. D. Southon, Z. Liu, M. E. R. Green, J. M. Hook, S. J.
Antill, C. J. Kepert, J. Phys. Chem. C 2008, 112, 15742.
[40] R. Mirsafaei, M. M. Heravi, S. Ahmadi, M. H. Moslemin, T.
[12] S. Barrientos‐Ramírez, E. V. Ramos‐Fernández, J. Silvestre‐
Albero, A. Sepúlveda‐Escribano, M. M. Pastor‐Blas, A.
González‐Montiel, Microporous Mesoporous Mater. 2009,
120, 132.
Hosseinnejad, J. Mol. Catal. A: Chem. 2015, 402, 100.
[41] S. Khaghaninejad, M. M. Heravi, T. Hosseinnejad, H. A.
Oskooie, M. Bakavoli, Res. Chem. Intermed. 2016, 42, 1593.

16 of 16
MALMIR ET AL.
[42] W. O. Yah, H. Xu, H. Soejima, W. Ma, Y. Lvov, A. Takahara,
[64] J. Safaei‐Ghomi, M. A. Ghasemzadeh, A. Kakavand‐Qalenoei,
J. Saudi, Chem. Soc. 2016, 20, 502.
J. Am. Chem. Soc. 2012, 134, 12134.
[43] F. Yu, H. Deng, H. Bai, Q. Zhang, K. Wang, F. Chen, Q. Fu,
[65] M. Tajbakhsh, M. Farhang, M. Baghbanian, H. Hosseinzadeh,
ACS Appl. Mater. Interfaces 2015, 7, 10178.
M. Tajbakhsh, New J. Chem. 2015, 39, 1827.
[44] M. C. Da Silva, E. C. Dos Santos, M. P. Lourenço, H. A. Duarte,
[66] A. Elhampour, M. Malmir, E. Kowsari, F. A. Boorboor, F.
J. Mol. Model. 2013, 19, 1995.
Nemati, RSC Adv. 2016, 6, 96623.
[45] R. Demichelis, Y. Noel, P. D'arco, L. Maschio, R. Orlando, R.
Dovesi, J. Mater. Chem. 2010, 20, 10417.
[67] K. V. V. Satyanarayana, P. Atchuta Ramaiah, Y. L. N. Murty, M.
R. Chandra, S. V. N. Pammi, Catalysis Commun. 2012, 25, 50.
[46] C. Lee, W. Yang, R. G. Parr, Phys. Rev. B 1988, 37, 785.
[47] V. Barone, M. Cossi, J. Phys. Chem. A. 1998, 102, 1995.
[68] F. Movahedia, H. Masrouria, M. Z. Kassaee, J. Mol. Catal. A.
2014, 395, 52.
[69] M. Trose, M. Dell'Acqua, T. Pedrazzini, V. Pirovano, E. Gallo,
E. Rossi, A. Caselli, G. Abbiati, J. Org. Chem. 2014, 79, 7311.
[48] H. Zhu, M. L. Du, M. L. Zou, C. S. Xu, Y. Q. Fu, Dalton Trans.
2012, 41, 10465.
[70] M. J. Albaladejo, F. Alonso, Y. Moglie, M. Yus, Eur. J. Org.
Chem. 2012, 2012, 3093.
[49] A. D. Becke, J. Chem. Phys. 1993, 98, 1372.
[50] Y. Zhao, D. G. Truhlar, Theor. Chem. Acc. 2008, 120, 215.
[51] P. J. Hay, W. R. Wadt, J. Chem. Phys. 1985, 82, 270.
[71] N. P. Eagalapati, A. Rajack, Y. L. N. Murthy, J. Mol. Catal. A.
2014, 381, 126.
[52] 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, J. A. Montgomery, J. Comput.
Chem. 1993, 14, 1347.
[72] P. Li, S. Regati, H.‐C. Huang, H. D. Arman, B.‐L. Chen, J. C.‐G.
Zhao, Chin. Chem. Lett. 2015, 26, 6.
[73] B. R. Prasad Reddy, P. V. Govardhana Reddy, M. V. Shankar, B.
N. Reddy, Asian J. Org. Chem. 2017, 6, 712.
[53] A. R. Chowdhuri, S. Tripathy, C. Haldar, S. Chandra, B. Das, S.
[74] F. Nemati, A. Elhampour, H. Farrokhi, M. Bagheri Natanzi,
Roy, S. K. Sahu, RCS Adv. 2015, 5, 21515.
Catal. Commun. 2015, 66, 15.
[54] H. Kumar, R. Rani, IJESIT 2013, 3, 344.
[55] C. Dablemont, P. Lang, C. Mangeney, J.‐Y. Piquemal, V.
Petkov, F. Herbst, G. Viau, Langmuir 2008, 24, 5832.
SUPPORTING INFORMATION
[56] S. Sadjadi, T. Hosseinnejad, M. Malmir, M. M. Heravi, New J.
Chem. 2017, 41, 13935.
Additional Supporting Information may be found online
in the supporting information tab for this article.
[57] J. Mondal, A. Modak, A. Dutta, S. Basu, S. N. Jha, D.
Bhattacharyya, A. Bhaumik, Chem. Commun. 2012, 48, 8000.
[58] J. Mondal, A. Modak, A. Dutta, A. Bhaumik, Dalton Trans.
2011, 40, 5228.
How to cite this article: Malmir M, Heravi MM,
Sadjadi S, Hosseinnejad T. Ultrasonic and bio‐
assisted synthesis of Ag@HNTs‐T as a novel
heterogeneous catalyst for the green synthesis of
propargylamines: A combination of experimental
and computational study. Appl Organometal Chem.
2018;e4291. https://doi.org/10.1002/aoc.4291
[59] I. Fleming, London: Wiley 1978, pp. 29.
[60] S. Sadjadi, M. Eskandari, Ultrason. Sonochem. 2013, 20, 640.
[61] M. S. Hosseini, F. Moeini, New J. Chem. 2014, 38, 624.
[62] M. Tajbaksh, M. Farhang, H. R. Mardani, R. Hosseinzadeh, Y.
Sarrafi, Chin. J. Cat. 2013, 34, 2217.
[63] L. Shi, Y.‐Q. Tu, M. Wang, F.‐M. Zhang, C.‐A. Fan, Org. Lett.
2004, 6, 1001.