The Pd(0) Nanoparticles Stabilized by Collagen Fibers as a Recyclable
Letters in Organic Chemistry, 2013, Vol. 10, No. 7 525
by drying in an oven. In every experiment, more than 98% of
the catalyst was easily recovered from the reaction mixture.
The catalyst was separated and was reused as such for sub-
sequent experiments under similar reaction conditions.
Yields of the product decreased only slightly after five times
reuse of catalyst (Table 3).
tion of aryl nitriles was confirmed by IR spectra, which
showed one characteristic peak for the CN stretching band
between 2225-2360 cm-1.
CONFLICT OF INTEREST
The author(s) confirm that this article content has no con-
flict of interest.
Table 3. Reusability of the Pd(0)-EGCG-CF catalyst.a
Recovery of Pd(0)-
EGCG-CF (%)
ACKNOWLEDGEMENTS
Entry
Yieldb (%)
We gratefully acknowledge from the Iranian Nano Coun-
cil and Islamic Azad University, Ahar Branch for the support
of this work.
Refresh
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92
92
90
90
88
99
99
99
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96
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3
4
5
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CONCLUSION
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S-N
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In conclusion, we have developed a simple and highly ef-
ficient method for the preparation of aryl nitriles using
Pd(0)-EGCG-CF as a recoverable and reusable catalyst. The
significant advantages of this methodology are high yields,
elimination of dangerous and harmful reagents and a simple
work-up procedure. Compared with previous procedures for
the cyanation of aryl bromides, the catalyst is inexpensive,
and the use of stoichiometric amounts of palladium and
K4Fe(CN)6 is avoided. Also, the catalyst was separated from
the reaction mixture and reused five times without signifi-
cant loss of catalytic activity.
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Preparation of Pd(0) Nanoparticles Stabilized by EGCG-
CF
The catalyst was prepared according to the literature [9e].
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Characterization of Catalyst
The catalyst was characterized by using powder XRD,
XPS, SEM, TEM and FT-IR spectroscopy [9e].
General Procedure for the Cyanation of Aryl Bromides
Under a dry nitrogen atmosphere, a mixture of aryl bro-
mide (1.0 mmol), K4Fe(CN)6 (0.22 mmol), base (1.0 mmol)
and Pd(0)-EGCG-CF (2.0 mol%) in DMF (5 mL) was stirred
at 130 °C for 8 h (Table 2). After completion (as monitored
by TLC), H2O was added and the organic layer was extracted
with EtOAc, washed with brine, dried over MgSO4, filtered
and evaporated under reduced pressure. The residue was
purified by column chromatography. All of the desired prod-
uct(s) were characterized by comparison of their physical
data with those of known compounds [4,5c,7]. The forma-
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