Bio-derived ZnO nanoflower: A highly efficient catalyst for the synthesis of chalcone derivatives

Article abstract of DOI:10.1039/c4ra14225j

The green, eco-friendly synthesis of ZnO nanoparticles using the peel of Musa balbisiana and their use as nanocatalysts in the synthesis of chalcones derivatives is reported here. Bio-derived ZnO nanoparticles were characterized by XRD, XPS, FTIR, SEM, BET and TEM techniques. The single step condensation of substituted aryl carbonyls is an attractive feature to obtain substituted chalcones in 88-98% yields in less than 2 min under microwave irradiation in solvent free conditions. A short reaction time with excellent yields of chalcones is the main advantage of our study.

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Graphical Abstract
Green, eco-friendly synthesis of ZnO nanoparticles using peel of Musa balbisiana and its utility as
nanocatalyst in synthesis of chalcone derivatives is reported
Zn(NO3)2
ZnO nanoflower
O
O
O
H
CH3
+
R
R

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Paper
Bio-derived ZnO nanoflower: A highly efficient catalyst for synthesis of chalcones
derivatives
Chandan Tamulya*, Indranirekha Saikiaa, Moushumi Hazarikaa, Manobjyoti Bordoloib, Najrul Hussainc, Manash R Dasc
Received (in XXX, XXX) Xth XXXXXXXXX 20XX, Accepted Xth XXXXXXXXX 20XX
5
DOI: 10.1039/b000000x
Green, ecoꢀfriendly synthesis of ZnO nanoparticles using peel of Musa balbisiana and its utility as nanocatalyst in synthesis of
chalcones derivatives is reported here. Bioꢀderived ZnO nanoparticles were characterized by XRD, XPS, FTIR, SEM, BET and TEM
techniques. The single step condensation of substituted aryl carbonyls is an attractive feature to obtain substituted chalcones with 88ꢀ98%
yield in less than 2 min under microwave irradiation in solvent free condition. Short time period with excellent yield of chalcones is the
10 main privilege in our study.
In this present investigation we synthesized ZnO nanoparticles,
50 a green and low cost method using peel of Musa balbisiana. This
procedure is environmentally benign for production of well
characterized nanoparticles without use of harsh, toxic and
expensive chemicals.
Furthermore, this procedure is more valuable due to its cost
55 effectiveness. Besides the green synthesis, the catalytic activity of
ZnO in the microwave synthesis of chalcones in solvent free
condition is reported.
1.Introduction
Among various metal oxides, ZnO nanoparticles have come to
the limelight for its semiconducting properties, unique
antibacterial, antifungal, wound healing and UV filtering
1
15 properties, high catalytic and photochemical activity . Over the
past several years, plants and different natural sources have come
up as a low cost, energyꢀefficient, ecoꢀfriendly and nonꢀtoxic
approach for synthesis of nanomaterials.2-3 These synthesized
nanoparticles have the advantage of good polydispersity,
20 dimensions and stability with a negligible synthesizing cost.
Moreover, using plants extract for nanoparticles synthesis can be
advantageous over other biological processes because it
eliminates the elaborate process of maintaining cell cultures and
can also be suitably scaled up for largeꢀscale nanoparticles
25 synthesis 4. Many examples are found in literature for ecoꢀ
2. Experimental Section
60
2.1. Materials
Materials used for the synthesis of ZnO nanoparticles are Zinc
nitrate [Zn(NO3)2.2H2O] (Merck, India) and Musa balbisiana
peel extract which was prepared by burning the peel of the plant.
65
friendly synthesis of ZnO nanoparticles using leaf extract such as
Corriandrum Sativum with Zn(CH3CO)2׳2H2O as precursor
Calotropis procera , seaweeds such as green Caulerpa peltata,
5
,
2.2. Synthesis of ZnO nanoparticles
6
In this method, the peel of Musa balbisiana was dried and then
burnt. To the 1 gm of ash of the peel, 10 ml of distilled water was
added and filtered. 4ml 1M Zn(NO3)2.2H2O solution was added to
70 the filtrate and stirred for 20 min. White precipitate was obtained.
The precipitate was then filtered and washed three/four times
with distilled water. The precipitate was heated for 2 h at 120ºC
temperature for the formation of powder ZnO nanoparticles. It is
the first report of ecoꢀfriendly green synthesis of ZnO
75 nanoparticles by using peel of Musa balbisiana.
7
red Hypnea Valencia and brown Sargassum myriocystum,
30 orange juice 8, Calotropis procera latex 9, aqueous leaf extract of
Acalypha indica 10, and leaf extract of Calotropis Gigantea 11
.
The Musa balbisiana is a medicinal and economic plant in
North East India. The peel of the plant is a food additive and
helps in normalizing digestive disorder of stomach. It is widely
35 used as soaps and detergents for washing clothes and shampooing
hairs 12-13
.
a Natural Product Chemistry Section, CSIR-North East Institute of
Science and Technology. Branch Itanagar Arunachal Pradesh-
791110, India, e-mail: c.tamuly@gmail.com, Telefax:
40 +913602244220
2.3. Characterization:
Scanning electron microscopy (SEM) characterization was
performed on JEOL JSM ꢀ 6360 at 15 kV. Xꢀray diffraction
80 (XRD) measurement were carried out by Rigaku Xꢀray
diffractometer (Model: ULTIMA IV, Rigaku, Japan) with CuꢀKα
Xꢀray source (λ = 1.54056 Å) at voltage 40 kV. Xꢀray
photoelectron spectroscopy (XPS) analysis was carried out on an
ESCALAB 300 (ThermoꢀVG Scientific). The high resolution
85 transmission electron microscopy (HRꢀTEM) images were
b Natural Product Chemistry Division, CSIR-North East Institute
of Science and Technology. Jorhat, Assam-785006, India
c Material Science Division, CSIR-North East Institute of Science
and Technology. Jorhat, Assam-785006, India
45 † Electronic Supplementary Information (ESI) available: [details of any
supplementary information available should be included here]. See
DOI:xxxxxxxx
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recorded by a JEOL Model 2100 EX, Japan operated at voltage of
as reported data 14
.
200 kV. Specific surface area, pore volume, average pore
diameter were measured with the Autosorbꢀ1 (Quantachrome,
USA). Specific surface area of the samples was measured by
adsorption of nitrogen gas at 77 K and applying the Brunauer–
Emmett–Teller (BET) calculation. Pore size distributions were
derived from desorption isotherms using the Barrett–Joyner–
Halenda (BJH) method. The 1H & 13C NMR spectra were
recorded at room temperature in CDCl3 solution on a Bruker
A
240000
220000
200000
180000
160000
140000
Zn 2p3/2
60
65
70
75
80
85
Zn 2p1/3
5
1020
1025
1030
1035
1040
1045
1050
1055
1060
Binding Energy(eV)
10 DPXꢀ300 spectrometer and chemical shifts were reported relative
to SiMe4
100000
95000
90000
85000
80000
75000
70000
65000
O 1 s
B
2.4. Claisen Schmidt condensation
Acetophenone (10 mmol), benzaldehyde (10 mmol) mixed with
15 ZnO nanoparticles (5mol %). Then the mixture was irradiated in
a microwave reactor for 1 min after setting reaction power at 40%
(maximum output 400 W) at 100ºC. After cooling to room
temperature ethyl acetate (15 ml) was added to the reaction
mixture and filtered the mixture through filter paper to separate
20 the solid catalyst. The ZnO catalyst could be used consecutively
for five times for the condensation of acetophenone and
benzaldehyde. After washing the filtrate the separated organic
layer was concentrated under reduced pressure and the product
was purified by column chromatography using hexane/ethyl
25 acetate as solvent system in different concentration to obtain the
pure compound.
52 2
524
526
528
530
532
534
536
538
540
B in d in g En erg y (eV )
Figure 2: XPS spectra of (A) Zn 2p and (B) O 1s of ZnO
nanoparticles
Results and Discussion
3.1. Characterization of ZnO nanoparticles
(A)
(B)
30 In the present investigation, ZnO nanoparticles are synthesized
using the peel of Musa balbisiana. It contained 233.60 gm of K+,
Figure 3: SEM images (AꢀB) of ZnO synthesized using Musa
2.00 gm of Na+, 161.40 gm of CO3 and 6.62 gm of Clꢀ when
2ꢀ
90 balbisiana
prepared from 1 kg of the ash 12-13. So, these ions may be
responsible for synthesis of ZnO nanoparticles [Scheme 1S,
35 supporting information (SI)].
In XPS analysis, the instrument was standardized against the C1s
spectral line at 284.6 eV. The binding energy of the Zn 2p3/2 and
Zn 2p1/2 component is recorded to be 1028.6 eV and 1051.8 eV
95 respectively (Figure 2A). The binding energy of O 1s is found at
530.16 eV (Figure 2B). Such results suggested that there is no
impurity existing within the sample. The result is supported by
reported data 15-16. In FTIR analysis, the peak observed at
3452.30 and 1119.15 cmꢀ1 may be due to OꢀH stretching and
100 deformation respectively of atmospheric vapours. The peaks at
1634.00 and 620.93 cmꢀ1 are corresponds to ZnꢀO stretching and
deformation vibration, respectively (Figure 1S, SI). The metalꢀ
oxygen frequencies observed for the respective metal oxide are in
3000
(101)
2500
(002)
(100)
2000
1500
40
(110)
1000
(112)
(103)
(102)
500
0
20
40
60
80
100
2Theta(degree)
45
accordance with literature values 17-18
.
Figure 1: XRD pattern of ZnO nanoparticles
105
The formation of ZnO nanoparticles was confirmed using
XRD, XPS, FTIR, SEM and TEM analysis. In XRD analysis, the
50 2θ values 31.7°, 34.4°, 36.3°, 47.4°, 56.6°, 62.8° and 67.9°
assigned (100), (002), (101), (102), (110), (103) and (112) plane
indicate the wurtzite structure of ZnO nanoparticles (JCPDS card
No. 36–1451). The corresponding ‘d’ spacing value of ZnO
nanoparticles are 2.87, 2.71, 2.49, 1.91, 1.54 and 1.35
55 respectively (Figure 1). All diffraction peaks of sample
correspond to the characteristic hexagonal wurtzite structure of
ZnO nanoparticles (a = 0.315 nm and c = 0.529 nm). It is similar
110
(A)
(B)
115 Figure 4: TEM image (AꢀB) of ZnO synthesized using Musa
2
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balbisiana
35 formation of pentagonal, hexagonal ZnO nanoparticless. The size
of the nanoparticles ranged 8.0±0.2–30.0±1.1 nm [Figure 3S, SI].
The average size of particles was 18.2±0.2 nm. In FTIR analysis
the peak at 3378 cmꢀ1, 1620 cmꢀ1, and 1122 cmꢀ1 accountable for
H2O and CO2 which usually take up from the environment
The SEM images indicate the formation of flower like
morphology of ZnO. The size of petal of ZnO nano flower is in
the range of 100ꢀ400 nm (Figure 3AꢀB). The flower like
5
morphology consists of petal like small nanosheets. However, it 40 [Figure 4S, SI]. The results supported by reported data 18. The
is difficult to examine the surface structure of the nanosheets by
SEM images and therefore it was examined by HRꢀTEM
analysis. The results showed the formation of flower like cluster
size and shape of the nanoparticless similar as synthesized using
peel extract of Musa balbisiana. So, from the observation it
revealed that the ions like K+, CO32ꢀ, Na+, Clꢀ etc may responsible
for synthesis of ZnO nanoparticles.
10 of ZnO nanostructure. The nanoparticles overlap each other
which strongly support the formation of flower like nanostructure
along with oval shape nanoparticles (Figure 4AꢀB). The size of
ZnO nanoparticles was found in the range of 5.0±0.2 – 22.0±1.2
nm. The average size of the particles is 10.5±0.8 nm. The
15 distance between the two atomic layers is 0.26 nm. The formation
of flower like structure of nanoparticles may be due to synergic
effect of ions like K+, CO32ꢀ, Na+, Clꢀ etc which are available in
the extract during synthesis of nanoparticles. Similar result was
45
3.2. Claisen Schmidt Condensation reaction
Table 1: Claisen Schmidt Condensation reaction
O
O
O
i) 5mol% ZnO NPs
CH3
H
+
ii) 100ºC
iii) MW
R
R
R= H, NO2, OH, F, Cl, OCH3, CH3
observed in other metal oxide with same precursors 12-13
.
Entry
1
Substrate
Product
Temp (ºC)
100
Time a (min)
0.8
Yield b (%)
98
TON
TOF(hꢀ1)
147.3
O
O
H
1.96
O
O
H
2
100
100
1.2
1.0
92
94
1.84
1.88
92.6
O2N
O2N
O
O
117.4
H
3
4
5
HO
HO
O
O
H
100
100
0.9
1.2
92
90
1.86
1.8
124.0
90.0
F
F
O
O
H
H3CO
H3CO
O
O
H
6
7
100
100
1.1
1.3
91
88
1.82
1.76
99.4
81.4
H3
C
H3C
O
O
H
Cl
Cl
Cl
Cl
a
20 Reactions performed at 80ºC
&
100ºC and monitored using TLC until all
50
the aldehyde and acetophenone were found to be consumed. b Isolated yield after
column chromatography with 2% standard deviation.
As we were emphasizing solvent less single step synthesis of
chalcones without using any protecting group, the reaction
between benzaldehyde (A) and acetophenone (B) was studied in
In order to understand the role of ions like K+, CO32ꢀ etc we have
25 performed an experiment using commercially available reagent. 55 detail taking equimolar mixtures of A and B under microwave
In this experiment ZnO nanoparticles was synthesized using
1mM K2CO3 with 1 mM Zn(NO3)2.2H2O then heated the
synthesized product at about 120ºC for 1 h. The synthesized
nanoparticles were characterized using XRD, TEM and FTIR
30 analysis.
In XRD analysis, the 2θ values 31.6°, 34.4°, 36.4°, 47.4°,
56.6°, 62.8° and 67.9° assigned (100), (002), (101), (102), (110),
(103) and (112) plane strongly indicated formation of ZnO
nanoparticless [Figure 2S, SI] The TEM image indicated the
irradiation in different conditions to optimize the reaction
We studied the reaction using ZnSO4, Zn(NO3)2, ZnCl2,
commercial ZnO nanopowder (characterized by XRD and TEM
analysis, supporting information Figure 5S& 6S), ZnO
60 nanocatalyst and without any catalyst. The results are presented
in Table 1S, SI. The reaction was carried out under solvent free
condition by mixing benzaldehyde and acetophenone in
microwave run at 100ºC and power at 40% (maximum output 400
W). No product was formed when catalyst was not used at 80°C
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and 100°C keeping the other reaction conditions unchanged as a
H3C
R'
control reaction (Table 1S, entries 1ꢀ2). From the table 1S, it was
observed that use of 5 mol% ZnO produce the best result (98%)
with in 0.8 min microwave irradiation at 100°C. Thereafter
reactions were carried out with different substituted aldehydes
and ketones [Table 1]. The electron donating and withdrawing
substituent in the aryl ring were well tolerated to give moderate
high yield of the desired chalcones. The result was found
significant and yield ranged 88ꢀ98 %. The isolated compounds
55
O
H
H
H
O
H
H
R
H
R
H
R'
R
H
R'
R
R'
H2C
R'
5
ꢀH+
H+
O-
-
O
OH
O
H
O
O
H
2-O
60
Zn2+ O2-
Zn2+ O2-
Zn2+ O2-
Zn2+ O2-
Zn2+ O2-
Zn2+ O2-
Zn2+ O2-
O
H
H
10 were characterised by 1H NMR, 13C NMR analysis. These data of
all products were comparable with the commercialized
compounds (Scheme 2S, SI).
Scheme 1: Plausible mechanism for condensation reaction
65 In the plausible mechanism, it has been observed that nanoꢀZnO
activates the aldehyde and react with the enol form of ketone to
form the condensed product. One H2O molecule was eliminated
from the condensed product to form 1,3ꢀDiphenylꢀ1ꢀ
Table 2: Recycling potential of ZnO nanocatalyst
No of cycle Run 1
Run 2
Run 3
Run 4
Run 5
94
Yield (%)
Time(min)
TON
98
97
96
95
phenylpropenone (chalcones) and its derivatives (Scheme 1) 19
.
0.8
0.8
0.8
0.8
0.8
70
1.96
147.3
1.94
145.8
1.92
144.3
1.90
142.8
1.88
141.3
Table 3: Comparison of NanoꢀZnO catalyst for chalcone
formation from benzaldehyde and acetophenone with earlier
report
TOF(hꢀ1)
15 Reaction condition, 10 mmol benzaldehyde, 10 mmol
acetophenone, 5mol% ZnO nanocatalyst
Sl
No
1
Catalyst
Time Temperature
(min)
Yield(%) Reference
BF3–Et2O/
Dioxane
I2ꢀAl2O3
(neutral)
NH4Cl/
15
1.5
3
Room
tempture
M.W.(300W) 95
60ºC
M.W. (480 95
W)
90
[20]
[19]
[21]
We have tested the reusability of ZnO catalyst in condensation
reaction of benzaldehyde and acetophenone. The ZnO catalyst
20 was recovered by filtration and was washed with hot
water/ethanol to remove any absorbed products. The catalyst was
reused without obvious loss of their catalytic activity, up to five
cycles and efficiency remain almost same (1st recycle 98%, 2nd
recycle 97% and 3rd recycle 96%, 4th recycle 95% and 5th recycle
25 94% chalcones was obtained) (Table 2). It was further confirmed
by using XRD and TEM analysis after 5th recycle [Figure 7S &
8S]. TEM and XRD investigation also showed that the activity,
morphology and size distribution of the ZnO nanocatalyst remain
unchanged after use of 5 times. Further investigation was done
30 for precise evidence through adsorption–desorption of nitrogen
molecule. The BET surface area and total pore volume of ZnO
was found to be 11.402 m2/g and 0.1859 m3/g respectively for the
fresh catalyst. The specific surface area of the recovered catalysts
decrease marginally to 140 (5th run) compared to 237 m2 g−1 of
35 freshly prepared catalyst [Figure 9S, SI]. The decrease of the
surface area of the catalyst after reaction may be due to the partial
destruction of the support by the small amount of base used in the
reaction. It was observed that the adsorption–desorption
hysteresis loop of the catalyst used in the 5th run ranging between
40 P/P0 = 0.3 and 0.9 shifted to P/P0 = 0.6 and 0.9, respectively. This
may be due to the change in the structure of pores. The BJH pore
size distribution curve of the recovered catalyst shows a slight
broadening of the distribution pattern compared to fresh catalyst
[Figure 10S, SI] indicating breakdown of the pore walls forming
45 larger pores. However, it is strongly supported that there is no
loss of efficiency of the catalyst after 5th recycle.
2
3
Solvent free
MW
4
5
6
BiCl3/Solvent 20
free
Phosphonium 150
Ionic Liquid
140 ºC
145ºC
100 ºC
85
80
98
[22]
[23]
NanoꢀZnO
0.8
Present
work
75 The catalytic performance of the chalcones is compared with
earlier supported catalyst and was observed the use of nanoꢀZnO
as catalyst in the reaction between benzaldehyde and
acetophenone under microwave irradiation at 100ºC, showed
highest yield of chalcones (Table 3). So, this is one of suitable,
80 simple, efficient method for synthesis of chalcones and its
derivatives.
4. Conclusion
It is a first report of green, efficient and ecoꢀfriendly synthesis of
85 ZnO nanoparticles using peel of Musa balbisiana. The ions like
2ꢀ
K+, Na+, CO3 etc may be responsible for the synthesis of ZnO
microꢀflower like nanostructure. We have developed a novel,
quick, environmentally safe and clean process for synthesis of
chalcone and its derivatives. The mild reaction conditions, easy
90 workꢀup, clean reaction profiles render this approach as an
interesting alternative to the existing methods.
Acknowledgement
The authors thank Director CSIRꢀNorth East Institute of Science
95 & Technology, Jorhat, Assam for providing facilities and
valuable advice. The authors also thankful to SAIF, Shillong for
TEM analysis. The authors thankful to SEED, Division, DST,
50
4
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and CSIR, New Delhi for financial support. IS thanks to CSIR
New Delhi for fellowship.
References
5
[1] E. Selvarajan, V. Mohanasrinivasan, Mater. Lett. 2013,112,
180–182.
[2] J. Huang, T. Kunitake, J. Am. Chem. Soc., 2003, 125 (39),
11834–11835
[3] X. Liu, Y. Gu, J. Huang Chemistry ꢀ A European Journal
10 2010, 16(26), 7730–7740.
[4] C. Krishnaraj, E.G. Jagan, S. Rajasekar, P. Selvakumar, P.T.
Kalaichelvan, N. Mohan, Colloids Surf. B: Biointerfaces 2010,
76, 50ꢀ56.
[5] D. Gnanasangeetha, S. Thambavani D, Res. J. Material Sci.
15 2013, 1, 1ꢀ8.
[6] P.S. Ravindra, K.S. Vineet, S.Y. Raghvendra, K.S. Prashant,
K.S. Prashant, C.P. Avinas, Adv. Mat. Lett., 2011, 2, 313ꢀ317.
[7] S. Nagarajan, K. A. Kuppusamy, J. Nanobiotech. 2013, 11,
39.
20 [8] A.K. Jha, V. Kumar, K. Prasad. J. Bionanosci., 2011, 5, 162–
166.
[9] R.P. Singh, V.K. Shukla, R.S. Yadav, P.K. Sharma, P.K.
Singh, A.C. Pandey, Adv. Mat. Lett. 2011, 2, 313ꢀ317.
[10] D. Gnanasangeetha , D. SaralaThambavani , J. Chem. Bio.
25 Phy. Sci. Sec. B, Nov. 2013ꢀJan .2014, 4, 238ꢀ246.
[11] C. Vidya, S. Hiremath, M.N. Chandraprabha, M.A. Lourdu
Antonyraj, I.Venu Gopal, A. Jain, K. Bansal, Int. J. Current Eng.
Tech. 2013, 1, 118ꢀ120.
[12] C. Tamuly, I. Saikia, M. Hazarika, M.R. Das. RSC Adv.
30 2014, 4, 20636ꢀ20640.
[13] C. Tamuly, I. Saikia, M. Hazarika, M.R. Das. RSC Adv.
2014, 4, 53229ꢀ53236.
[14] SweeꢀYong Pung, WenꢀPie Lee, Azizan Aziz, Int. J. Inorg.
Chem. 2012, 2012, 1ꢀ9.
35 [15] X. Wang, F. Zhao, P. Xie, S. Liang, S. Deng, N. Xu. Opt.
Commun. 2007, 276, 186–190
[16] D.I. Son. J. Korean Phys. Soc. 2009, 55 (5),1973ꢀ1976.
[17] A. Sharma, B.P. Singh, S. Dhar, A. Gondor, M. Spasova,
Surf. Sci. 2012, 606, L13–L17.
40 [18] R. Amutha, G.ꢀJ. Lee, E. Repo, M. Sillanpaa, J.J. Wu, Mater.
Lett. 2013, 107, 64–67
[19] D. Kakati and J.C. Sarma Chemistry Central Journal 2011, 5,
8
[20] T. Narender, K.P. Reddy. Tetrahedron Lett. 2007, 48,
45 3177–3180
[21] R. Pal. IOSR J.Appl. Chem. (IOSRꢀJAC) 2013, 3(4), 74ꢀ80
[22] D. Kumar, Suresh, J. S. Sandhu. Green Chem. Lett. Rev.
2010, 3(4), 283ꢀ286
[23] S.R. Sarda, W.N. Jadhav, S.U. Tekale, G.V. Jadhav, B.R.
50 Patil, G. S. Suryawanshi, Rajendra P. Pawar. Lett. Org. Chem.
2009, 6, 481ꢀ484
This journal is © The Royal Society of Chemistry [2014]
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