A rapid and simple route for the synthesis of lead and palladium nanoparticles in tetrazolium based ionic liquid

Article abstract of DOI:10.1016/j.saa.2010.11.039

In the present work, we report a novel method for the synthesis of palladium and lead nanoparticles by the reduction method in tetrazolium ring based ionic liquid. Palladium and lead nanoparticles so-prepared were well characterized by powder X-ray diffraction measurements (pXRD), transmission electron microscopy (TEM) and quasi elastic light scattering (QELS) techniques. Powder X-ray diffraction (pXRD) analysis revealed all relevant Bragg's reflection for crystal structure of palladium and lead. Powder X-ray diffraction plots also revealed no oxidized material of palladium and lead nanoparticles. TEM showed nearly uniform distribution of the particles in methanol and confirmed by QELS. Typical applications of palladium nanoparticles include in vitro use and sensor design applications. Palladium nanoparticles is also ideal for spin coating, self-assembly and monolayer formation. Palladium nanoparticles can also be considered as potential new catalysts.

Full text of DOI:10.1016/j.saa.2010.11.039

Spectrochimica Acta Part A 78 (2011) 909–912
Contents lists available at ScienceDirect
Spectrochimica Acta Part A: Molecular and
Biomolecular Spectroscopy
journal homepage: www.elsevier.com/locate/saa
Short communication
A rapid and simple route for the synthesis of lead and palladium nanoparticles in
tetrazolium based ionic liquid
Prashant Singha,∗, Pradeep Kumarb, Kamlesh Kumaric, Pankaj Sharmaa, Subho Mozumdarb,
Ramesh Chandrab
a A. R. S. D. College, University of Delhi, Delhi-110007, India
b Department of Chemistry, University of Delhi, Delhi-110007, India
c Department of Chemistry, Jamia Hamdard, New Delhi-110062, India
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 2 June 2010
Received in revised form 28 October 2010
Accepted 30 November 2010
In the present work, we report a novel method for the synthesis of palladium and lead nanoparticles
by the reduction method in tetrazolium ring based ionic liquid. Palladium and lead nanoparticles so-
prepared were well characterized by powder X-ray diffraction measurements (pXRD), transmission
electron microscopy (TEM) and quasi elastic light scattering (QELS) techniques. Powder X-ray diffrac-
tion (pXRD) analysis revealed all relevant Bragg’s reflection for crystal structure of palladium and lead.
Powder X-ray diffraction plots also revealed no oxidized material of palladium and lead nanoparticles.
TEM showed nearly uniform distribution of the particles in methanol and confirmed by QELS. Typical
applications of palladium nanoparticles include in vitro use and sensor design applications. Palladium
nanoparticles is also ideal for spin coating, self-assembly and monolayer formation. Palladium nanopar-
ticles can also be considered as potential new catalysts.
Keywords:
Palladium and lead
Green synthesis
pXRD
TEM and QELS
© 2010 Elsevier B.V. All rights reserved.
1. Introduction
Because of their tunable polarity and hydrophobicity, they can
solvate various organic, inorganic, and polymeric compounds, and
Over the past few years, research has been directed towards
the synthesis and application of metal nanoparticles in view of
their unique properties compared to the bulk metals [1,2]. Lead
and palladium nanoparticles have received considerable attention
because of their unusual properties and potential applications in
diverse fields especially chemical reactions [3]. The various syn-
thetic procedures for their synthesis includes micro emulsion, [4]
reverse micelles, [5] reduction of aqueous lead and palladium salts,
[6] UV-light irradiation, [7–9]. The core–shell particles are of great
interest due to their potential applications in diverse fields includ-
ing catalysis, reductions etc. [7–10]. There is considerable interest
in the use of room temperature ionic liquids as promising substi-
tutes for volatile organic solvents. Ionic liquids have been employed
as reaction media for several organic reactions, namely alkylation
[11], hydrogenation [12], oxidation [13].
have been used as green solvents for liquid–liquid separations,
extractions, and recycling in homogeneous catalysis. Along with
these qualities ionic liquids provides stability to metal nanoparti-
cles and give small size particles. Palladium and lead are widely
used materials in the world. It has a great significance in all indus-
tries, particularly in the pharmaceutical sector. Palladium and lead
nanoparticles have been synthesized and characterized by differ-
ent methods. Stability and reactivity are the two important factors
that impede the use and development of the metal cluster [22–26].
Ionic liquid have very important in the preparation of Pb and Pd
nanoparticles as they acts as solvent as well as they provide stabil-
ity to the nanoparticles. We cannot prepare these nanoparticles in
aqueous system because they get oxidized and forms metal oxide.
The fields that have recently been greatly impacted by the
advancement in nanostructured materials are biology, biophysics,
and medicine. The nanobiology toolkit has been greatly enhanced
by noble metal nanostructures, which have proven to be highly ver-
satile and tunable materials for a range of bioapplications including
biophysical studies, biological sensing, imaging, medical diagnos-
tics, and cancer therapy. In this account, we describe the interesting
optical properties of noble metal nanostructures and discuss recent
research advances in their bioapplications.
Palladium nanostructures have been known as catalysts for the
reactions such as oxidation of hydrocarbon in automobiles (three-
way catalyst), Heck reaction, Suzuki reaction, Stille coupling and
C–N coupling. Also, Pd nanoparticles with preferentially exposed
(1 1 1) show high catalytic activity for the hydrogenation of 1,3-
butadiene [14–21].
Some of the methods are sonochemical, ꢀ-irradiation, UV-
irradiation, microemulsion technique and polyol reduction.
However, the facile, cost-effective and large-scale synthetic meth-
∗
Corresponding author. Tel.: +91 11 24113436.
E-mail address: arsdchemistry@yahoo.in (P. Singh).
1386-1425/$ – see front matter © 2010 Elsevier B.V. All rights reserved.
doi:10.1016/j.saa.2010.11.039

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P. Singh et al. / Spectrochimica Acta Part A 78 (2011) 909–912
Scheme 1. Synthesis of tetrazolium ring based ionic liquid.
ods are still elusive. Herein, we report a simple, rapid and room
temperature synthesis of Pd nanoparticles in tetrazolium based
ionic liquid and characterized by powder X-ray diffraction, TEM
and QELS techniques.
compound and 15 mmol of bromobutane were taken in 100 ml
round bottom flask having 25 ml of acetonitrile. Reflux the mix-
ture for 6 h and evaporate the solvent and excess of bromobutane
under reduced pressure as in Scheme 1 [22–26].
2. Experimental
2.2.2. Synthesis of palladium nanoparticles in ionic liquid (A)
In a round bottom flask, 5 ml of the synthesized ionic liquid
was taken and 25 mg of palladium acetate was added then excess
of methanolic solution of sodium borohydride (20 mg in 10 ml of
methanol) was added in the flask. Suddenly a brownish-black color
solution was obtained indicates the Pd (0) particles (Scheme 2).
The stirring was continued for 3 h. The above solution was taken in
2.1. Reagents and analysis
All reactions were carried out at ambient temperature in oven-
dried glassware. The materials were purchased from Sigma–Aldrich
and Merck used. The metal nanoparticles were systematically char-
acterized by powder X-ray diffraction, TEM and QELS techniques.
Nanosize and morphology of the palladium and lead nanoparticles
were observed under Philips TECNAI-FE12 Transmission Electron
Microscope (120 kV). The particles were dispersed in methanol and
a drop of it was placed on Formvar-coated copper grid followed
by air-drying. The X-ray diffraction patterns were recorded using
a RIGAKU ROTAFLEX RAD-B by Rigaku corporation Japan diffrac-
tometer using Cu target Cu K␣ 1 radiation with tube voltage 40 kV
and 60 mA in 2ꢁ ranging from 5◦ to 60◦.
Powder XRD of Palladium
400
a
300
200
100
0
2.2. Synthesis of catalyst
2.2.1. Synthesis of ionic liquid (A)
First Step, in a 50 ml round bottom flask, 10 mmol of 1H-
tetrazole-5-acetic acid and 15 mmol of acrylonitrile in 20 ml of
acetonitrile was taken. The mixture was stirred for 2 h approxi-
mately. Completion of the reaction was checked with thin layer
chromatography. Evaporate the solvent and excess of acrylonitrile
under reduced pressure. Second step, now 10 mmol of the above
5
10 15 20 25 30 35 40 45 50 55 60 65 70
2 Theta
Powder XRD of lead nanopaticles
600
500
400
300
200
100
0
b
Ionic liquid
Pb (CH3COO)2
Pd (0)
Methanolic solution of NaBH4
Scheme 2. Synthesis of palladium nanoparticles in ionic liquid.
Ionic liquid
Pd (NO3)2
Pb (0)
5
10 15 20 25 30 35 40 45 50 55 60 65 70
2 Theta
Methanolic solution of NaBH4
Scheme 3. Synthesis of lead nanoparticles in ionic liquid.
Fig. 1. Powder X-ray diffraction curve of (a) palladium and (b) lead nanoparticles.

P. Singh et al. / Spectrochimica Acta Part A 78 (2011) 909–912
911
Fig. 3. QELS picture of (a) palladium and (b) lead nanoparticles.
nature of the sample. Lead nanoparticles were well characterized
with powder-X-ray diffraction, TEM and QELS techniques. Powder
X-ray diffraction pattern of the lead nanoparticles shows signature
for Pb (0) as shown in Fig. 1(b). The peaks at 28.6, 31.2, 36.8, 52.1
and 62.6 in the powder X-ray diffraction plot confirm the presence
of Pb (0) in the sample.
TEM studies of palladium nanoparticles were carried out to
understand the shape and size of the particles. Fig. 2(a) shows
the transmission electron micrographs of palladium nanoparticles
are 35 nm in diameter with spherical shape. TEM studies of lead
nanoparticles were carried out to understand the shape and size of
the particles. Fig. 2(b) shows the transmission electron micrographs
of lead nanoparticles are 70 nm in diameter with spherical shape.
The particles size of palladium and lead nanoparticles was con-
firmed by QELS of palladium and lead nanoparticles as in Fig. 3(a)
and (b).Conclusion
Fig. 2. Transmission electron microscope picture of (a) palladium and (b) lead
nanoparticles.
ethanol and then centrifuges the solutions at 6000 rpm for 20 min
and decants the supernatant and washed it with ethanol (3×) and
dried with nitrogen gas thoroughly. Then the dried material was
weighed and analyzed by powder X-ray diffraction, TEM and QELS
techniques. (Yield = 10.621 mg)
The present study illustrates simple, convenient and signifi-
cant methods for the synthesis of palladium and lead nanoparticles
through the reduction of palladium and lead respectively in ionic
liquid.
2.2.3. Synthesis of lead nanoparticles in ionic liquid (A)
In a round bottom flask, 5 ml of the synthesized ionic liquid was
taken and 25 mg of lead nitrate was added then excess of methano-
lic solution of sodium borohydride (15 mg in 10 ml) was added in
the flask. Suddenly a white color solution was obtained indicates
the lead (0) particles (Scheme 3). The stirring was continued for 2 h.
The above solution was taken in ethanol and then centrifuges the
solutions at 4000 rpm for 20 min and decants the supernatant and
washed it with ethanol (3×) then the left material was dried with
nitrogen gas thoroughly. Then the dried material was weighed and
analyzed by powder X-ray diffraction, TEM and QELS techniques
(Yield = 14.568 mg).
Acknowledgement
This work is dedicated to late Dr. N.N. Ghosh (Dr. Prashant
Singh).
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