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the product was extracted with dichloromethane. The catalyst
was separated by centrifuge and carefully washed with
ꢁ
dichloromethane. The catalyst was dried under vacuum at 70 C
and then re-used in the cross-coupling reaction.
Characterization
Scanning electron microscopic (SEM) images were recorded on
a Hitachi S-4800 led emission scanning electron microscope
(FE-SEM). Transmission electron microscopic (TEM) and
elemental mapping images were taken by a JEM-2100F with an
accelerating voltage of 200 kV. FT-IR spectra were obtained by
a Shimadzu IR-460 spectrometer. Aer separation of the catalyst
Fig. 1 General pathway for the synthesis of Pd@TU-PMO.
4
with centrifuge, the organic liquor was dried over MgSO ,
evaporated in vacuo and the organic residue was (if necessary, it
1
was puried by column chromatography) analyzed by H and
3
2
0 min. Aer complete evolution of H S gas from reaction
1
3
1
13
C NMR. H and C NMR spectra were obtained on a JEOL
mixture, indicating completion of the reaction, the mixture was
cooled to room temperature and the nal product was produced
as a dark yellow liquid. This product was characterized by both
2
9
Delta, 300 MHz spectrometer. Si magic-angle spinning (MAS)
1
3
NMR spectra and C cross-polarized (CP) MAS NMR spectra
were recorded at 119.17 MHz on a Varian 600PS solid-state NMR
spectrometer using a 6 mm diameter zirconia rotor. Low-angle
XRD patterns were collected on a Rigaku NANO-Viewer (Cu Ka).
1
13
H-NMR and C-NMR and was used as-is in the next step
Fig. S2 and S3†).
(
N
2
adsorption–desorption isotherms were measured using
Preparation of TU-PMO
a Quantachrome Autosorb at 77 K. X-ray photoelectron spec-
Typically, 2 g of P123 was dissolved in 75 mL HCl(aq) (2 M) and troscopy (XPS) spectra were obtained on a 8025-BesTec twin
allowed to stir for several hours to obtain a clear solution. Then, anode XR3E2 X-ray source system at room temperature; all
ꢁ
the solution was warmed to 40 C for 4 h. Aer this time, spectra were calibrated to C1s (285.0 eV) as a reference. The Pd
a mixture of the bis-thiourea prepared above (2 mmol) and loading amount was determined by inductively coupled plasma
TEOS (16 mmol, 3.7 mL) was added to the solution drop-wise atomic emission spectroscopy (ICP-AES) on a Perkin Elmer
and the reaction allowed to stir for 24 h. Aer this time, the 2100DV.
ꢁ
reaction was stopped and aged at 100 C with the same liquor
for 24 h. Aerwards, the resulting yellow solid was collected by
Results and discussion
ltration and extracted in a Soxhlet for 3 days with EtOH as an
eluent. CHN analysis of TU-PMO was obtained and results
showed that the percentage of organic loading is 19 wt%.
Aer synthesis of Pd@TU-PMO, its Pd content was calculated to
be 3.7 wt% according to ICP-AES analysis. XPS measurement
was carried out for the Pd supported TU-PMO before and aer
Synthesis of Pd@TU-PMO
reduction with NaBH
terized peaks at 337.9 and 334.1 eV can be assigned to Pd in the
2 oxidation state before reduction with NaBH . A small peak
4
(Fig. S4†). The presence of two charac-
4
NaPdCl (0.10 g) was dissolved in distilled water (5 mL) and this
solution was added to a suspension of TU-PMO (1 g) in EtOH (20
mL). Aer stirring for 1 h at rt, the resulting solid was collected,
+
4
shi aer reduction with NaBH
been reduced to its metallic form.
The N adsorption–desorption isotherm for TU-PMO shows
4
shows that the Pd species has
washed with EtOH and dried in a vacuum oven for 60 min at
ꢁ
2
6
0 C. The resulting solid was then dispersed in MeOH (20 mL)
a typical type IV isotherm, which has been seen in SBA-15 type
mesoporous silica (Fig. 2a). The BET surface area was calculated
and a solution of NaBH (19 mg) in MeOH (10 mL) was added
4
dropwise. Aer stirring for 30 min at room temperature, the
2
ꢀ1
to be ca. 410 m g (Table S1†). Even aer deposition of Pd
nanoparticles, the high surface area still remained (Table S1†).
The average pore sizes were estimated to be ca. 6.1 nm. Low-
nal resulting solid was collected by ltration, washed and
ꢁ
dried at 60 C in vacuum oven. The nal product was named
Pd@TU-PMO.
angle XRD patterns for TU-PMO shows one sharp peak at
ꢁ
2
q ¼ 0.92 (d10 ¼ 9.60 nm), which originates from the period-
General procedure for Suzuki–Miyaura reactions
icity of the mesoporous structure (Fig. 2b). Aer the Pd depo-
In a typical procedure, an aryl halide (2 mmol) and arylboronic sition, this peak was maintained and slightly shied to higher
ꢁ
acid (2.1 mmol) were added to a mixture of K
Pd@TU-PMO (57 mg) in 5 mL H
to stir at room temperature and monitored by GC. The reaction band at 3265 cm can be attributed to N–H stretching and two
2
CO
3
(4 mmol) and degree (2q ¼ 0.95 , d10 ¼ 9.30 nm). The framework of TU-PMO
2
O. The reactions were allowed was characterized by FT-IR analysis (Fig. 2c). A broad and small
ꢀ
1
ꢀ1
conversion and product yield were also determined using GC sharp peaks at 2974 and 2928 cm can be attributed to the
with biphenyl as an internal standard. For the recycling study, asymmetric and symmetric stretching mode of aliphatic C–H
7
ꢀ1
aer reaction completion, the reaction mixture was diluted and bonds in propyl chain, respectively. A small peak at 2887 cm
This journal is © The Royal Society of Chemistry 2017
RSC Adv., 2017, 7, 56306–56310 | 56307