Z. Nasresfahani and M.Z. Kassaee
2. Experimental
Journal of Organometallic Chemistry 937 (2021) 121703
2.1. Material and instrumentation
Fourier transform infrared (FT-IR) spectra are recorded by a
Nicolet IR-100 infrared spectrometer using KBr pellets in the range
400–4000 cm−1. The nuclear magnetic resonance (NMR) spectra
are recorded using a Brucker DRX 300-Avance spectrometer, op-
erating at 300 and 75 MHz in CDCl3 as solvent in the presence of
tetramethylsilane (TMS) as internal standard. X-ray powder diffrac-
tion (XRD) is performed using Philips XPert (1730 diffractometer).
The latter appears with Cu Kα (α = 1.54056 Ao) and voltage of
40 kV. Surface area and isotherm are tested by N2 adsorption–
desorption (Micrometritics, TriStar II 3020 surface area and poros-
ity analyzer). The particle morphology is examined by scanning
electron microscopy (SEM) [(HITACHI S-4160)], on gold coated
samples. Shimadzu-UV-2550-8030 spectrophotometer is used for
analysis of the UV-Vis diffuse reflectance spectroscopy (DRS) in the
range of 190-800 nm.
2.2. Preparation of the catalyst
The Ni/Cu-MCM-41 is prepared through co-condensation
method [41]. According to this procedure, about 0.65
g of
cetyltrimethylammonium bromide (CTAB) is dissolved in 50 mL of
H2O and ethanol. Afterwards, 4 mL of an aqueous NH3 solution
containing 0.102 g of Cu(NO3)2. 3H2O and 0.5 g of Ni(NO3)2. 6H2O
is added to formation a dark blue color solution. Subsequently,
about 3.2 mL of tetraethyl orthosilicate (TEOS) is added and stirred
for 2 h at room temperature (RT). This procedure is followed by fil-
tering blue color product, washing it with deionized water, drying
at 75°C overnight, and calcination at 540°C, for 18 h.
2.3. General procedure for the Sonogashira coupling reaction in the
presence of the Ni/Cu-MCM-41
A mixture of phenylacetylene (1.2 mmol), aryl halide (1 mmol),
KOH (2 mmol), DMF (5 mL) and Ni/Cu-MCM-41 (20 mg) are added
into a 25 mL flask. The resulting mixture is stirred at 120 °C for ap-
propriate reaction time. Progress of reactions is monitored by TLC.
After completion of the reaction, the catalyst is separated by cen-
trifugation. Then, the reaction mixture is extracted with ethyl ac-
etate and water. The organic phase is dried by addition of MgSO4
and concentrated under reduced pressure. The residue is purified
by column chromatography.
3. Results and discussion
3.1. Characterization of the catalyst
Upon synthesis, Ni/Cu-MCM-41 is characterized by FT-IR, SEM,
XRD, DRS, energy dispersive X-ray spectroscopy (EDX), and nitro-
gen adsorption–desorption analysis.
FT-IR spectra of MCM-41 (Mobil Composition of Matter No. 41)
and Ni/Cu-MCM-41 are recorded in the range of 400–4000 cm−1
(Fig. S1 of the SI). In both spectra, the broad band at around
3430 cm−1 is correlated to the hydroxyl stretching vibrations of
Fig. 1. Nitrogen adsorption–desorption isotherms (a) and pore size distribution (b)
of MCM-41 and Ni/Cu-MCM-41.
the silanols and adsorbed water molecules, also the H O H bend-
ing vibration of water molecules is assigned at around 1635 cm−1
For MCM-41, the band at 1088 cm−1 can be assigned to asymmet-
observed at 459 cm−1. These results demonstrate the successful in-
corporation of transition metals in the framework of MCM-41.
The crystal structure of sample is characterized by XRD mea-
surement (Fig. S2 of the SI). The low angle XRD pattern of Ni/Cu-
MCM-41 exhibits a strong peak in 2θ =1.24, due to the d100 plane,
which is the characteristic diffraction pattern of the ordered hexag-
onal symmetry of mesoporous material. Comparison of XRD pat-
tern of Ni/Cu-MCM-41 with MCM-41 indicates a decrease in 2θ
–
–
.
–
–
ric Si O Si stretching vibration. It can be seen in FT-IR spectra of
Ni/Cu-MCM-41 that this band is shifted to the lower wave num-
ber at 1083 cm−1, because substitution of Si atoms with Cu and Ni
causes the longer bond lengths of Cu–O and Ni–O bonds in com-
–
–
parison with Si–O bonds. In addition, Si O Si bending vibration is
2