Synthesis, characterization and antimicrobial studies of a new mannich base N-[morpholino (phenyl)methyl]acetamide and Its cobalt(II), nickel(II) and copper(II) metal complexes

Article abstract of DOI:10.1155/2012/767941

A new Mannich base N-[morpholino(phenyl)methyl]acetamide (MBA), was synthesized and characterized by spectral studies. Chelates of MBA with cobalt(II), nickel(II) and copper(II) ions were prepared and characterized by elemental analyses, IR and UV spectral studies. MBA was found to act as a bidentate lig and , bonding through the carbonyl oxygen of acetamide group and CNC nitrogen of morpholine moiety in all the complexes. Based on the magnetic moment values and UV-Visible spectral data, tetracoordinate geometry for nitrato complexes and hexacoordinate geometry for sulphato complexes were assigned. The antimicrobial studies show that the Co(II) nitrato complex is more active than the other complexes.

Full text of DOI:10.1155/2012/767941

ISSN: 0973-4945; CODEN ECJHAO
E-Journal of Chemistry
http://www.ejchem.net
2012, 9(2), 875-882
Synthesis, Characterization and Antimicrobial
Studies of a New Mannich Base N-[Morpholino
(phenyl)methyl]acetamide and Its Cobalt(II),
Nickel(II) and Copper(II) Metal Complexes
L. MURUGANANDAMA* and K. KRISHNAKUMARB
aDepartment of Chemistry,
Saranathan college of Engineering, Tiruchirapalli-12, India
bDepartment of Chemistry,
National Institute of Technology, Tiruchirapalli-15, India
lmuruganandam@yahoo.co.in
Received 6 August 2011; Accepted 21 October 2011
Abstract: A new Mannich base N-[morpholino(phenyl)methyl]acetamide
(MBA), was synthesized and characterized by spectral studies. Chelates of
MBA with cobalt(II), nickel(II) and copper(II) ions were prepared and
characterized by elemental analyses, IR and UV spectral studies. MBA was
found to act as a bidentate ligand, bonding through the carbonyl oxygen of
acetamide group and CNC nitrogen of morpholine moiety in all the complexes.
Based on the magnetic moment values and UV-Visible spectral data,
tetracoordinate geometry for nitrato complexes and hexacoordinate geometry
for sulphato complexes were assigned. The antimicrobial studies show that the
Co(II) nitrato complex is more active than the other complexes.
Keywords: Chelates, Inhibition, Stoichiometry, Multiplet, Stereochemistry, Fungitoxicity.
Introduction
Metal chelates of Mannich bases form an interesting class of compounds, which find extensive
applications in various fields1,2. Among the very few number and variety of transition, inner
transition and main group metal complexes of Mannich bases, those formed from bivalent
transition metals are of particular interest, because of their synthetic flexibility, structural
diversities, bonding interactions, biological significance, and other multiple applications3-5. We
report here, the synthesis of the Mannich base MBA, which is a bidentate ligand. For, it
contains two donor atoms: carbonyl oxygen and CNC nitrogen. With this ligand CoII, NiII, and
CuII (in the molar ratio 1:2) complexes have been prepared.

876 L. MURUGANANDAM et al.
Experimental
High purity acetamide(Merk), benzaldehdye(Merk), morpholine(Merk) were used as
supplied. All other solvents and metal salts used were of A.R. grade and used as received.
Synthesis of the Ligand
N-[Morpholino(phenyl)methyl]acetamide(MBA) was synthesized by employing the
Mannich synthetic route7: Acetamide (5.90 g, 0.1 mol) was dissolved in minimum quantity
of ethanol. To this solution, benzaldehdye (10 mL, 0.1 mol) followed by morpholine (9 mL,
0.1 mol) were added in small quantities with constant stirring in an ice bath. After 28 days, a
yellow solid was obtained. It was washed with water and with acetone. The compound was
dried in air and then at 60oC in an air oven and recrystallised from ethanol. The percentage
yield of the compound was 73 and its melting temperature was 148-150oC.
Synthesis of the Complexes
The hot methanolic solution of the metal salt was added slowly with constant stirring to the
hot ethanolic solution of the ligand in 2:1 mol ratio. The insoluble complexes8 formed, were
filtered, washed with methanol and ethanol to remove the unreacted metal and ligand, dried
in air and then in an air oven at 80oC.
Instruments
Micro elemental (C, H, and N) data were obtained with Carlo Erba 1108 elemental
analyzer at RSIC, CDRI, Lucknow. Metal contents were estimated by usual procedure,
after digesting the complexes with con. HNO3. Sulphate was estimated gravimetrically
as BaSO4 and chlorides were estimated volumetrically by Volhard’s method6. The
conductance data were obtained in ~10-3 M DMF solutions of the complexes at room
temperature using a Systronics direct reading digital conductivity meter-304 with dip
type conductivity cell. IR spectra were recorded using a spectrum-one Perkin Elmer FT-
IR spectrometer employing KBr pellets. The UV-Visible regions were recorded in DMF
solutions using double beam UV-Visible spectrometer, Perkin EZ-301 of working range
1
1100-190 nm. The H and 13C NMR of the ligand were recorded on a Bruker instrument
and on a JEOL-GSX 400 spectrometer employing TMS as internal reference and
DMSO-d6 as solvent. The FAB mass recorded for the ligand was carried out using a
JEOL GC mate mass spectrometer. Electrochemical studies were performed on a Bio-
Analytical System CV-50W electrochemical analyzer with three-electrode system of a
glassy carbon electrode as the working electrode, a platinum wire as auxiliary electrode
and Ag/AgCl as the reference electrode. The room temperature magnetic susceptibility
measurements of the complexes were made by using a Gouy magnetic balance
calibrated using mercury(II)tetrathiocyanatocobaltate(II).
Antimicrobial Studies
Antimicrobial activities9 of MBA and their metal complexes, such as CoII, NiII, and CuII
were tested in vitro against six bacterial species E.coli, P.aeruginosa, S.typhi, B.subtilis,
S. pyogenes, and S.aureus and the fungal species A. niger and A.flavus by disc diffusion
method using agar nutrient as medium and gentamycin as control. The paper disc
containing the compound (10, 20, and 30 μg/disc) was placed on the surface of the
nutrient agar plate previously spread with 0.1 mL of sterilized culture of
microorganism. After incubating this at 37oC for 24 h, the diameter of inhibition zone
around the paper disc was measured.

Synthesis, Characterization and Antimicrobial Metal Complexes
877
Results and Discussion
Characterization of the Ligand
Infrared spectrum of MBA shows a sharp peak at 3297 cm-1, which may be assigned to the
νNH of the secondary amide group10. The strong band at 1647 cm-1 may be attributed to the
νC=O stretching mode. The other strong bands appearing at 1493, 1449, and 1206 cm-1 are
indicative of bending vibrations of the methylene (δCH2) group and stretching vibration of
the morpholine ring (νring). The medium absorption band at 1116 cm-1 suggests the presence
of new C-N-C bond pertaining to the formation of Mannich base by the insertion of
morpholinobenzyl group on acetamide. The absorption band present at 1140 and 1072 cm-1
may be assigned to the C-N-C frequency of morpholine. The strong bands at 1049 and
1034 cm-1 may be attributed to νC-O-C frequency of morpholine group. The band at 749 cm-1
indicates the presence of monosubstitution of morpholine in MBA.
The UV-Visible spectrum11 in DMF registers two intense split bands centered at 286 nm
and 242 nm, which are presumably due to n→π* transition of the carbonyl group and π→π*
transition of the carbonyl group and the benzene ring.
The IH NMR signal at δ=8.44 ppm may be assigned to the secondary amide NH proton.
The methine proton shows a signal at δ=5.61 ppm. The multiplet in the range
δ=7.44-7.28 ppm (7.44 ppm for C at the position 2&6 and the peaks at δ=7.36 and
δ=7.28 ppm for C at 3&5 and 4, respectively) attributed to the protons of the benzene ring12.
The chemical shift of the protons of N(CH2)2 group of morpholine ring occurs at
δ=2.51 ppm. The chemical shift of the protons of O(CH2)2 group of morpholine occurs at
δ=3.58 ppm.
The 13C NMR spectrum13 shows the carbonyl carbon at δ=170.13 ppm. The signals
observed between δ=139.71-127.76 ppm are due to aromatic carbons of benzamide. The
resonance signals at δ=139.71, 128.64, 127.93 and 127.76 ppm are assigned to the carbons
of the phenyl group at 1, 2&6, 3&5 and 4 positions respectively. The signals due to the C1
carbon of benzene ring can be differentiated by its decreased peak height of δ=139.71 ppm.
The signal at δ=66.70ppm is due to the O(CH2)2 group and that at δ=48.98 ppm is due to
N(CH2)2 carbon of morpholine.
The mass spectrum14 of MBA was obtained on electron ionization mode, showing a
very weak molecular ion peak at m/z = 234. This confirms the already assigned molecular
mass to the Mannich base understudy. Thereupon, on fragmentation, intense signals at m/z =
-
143 & m/z = 114 are recorded. They are due to the removal of C6H5CH2 and CHO- groups
respectively. The next m/z signal at 86 is due to morpholine ion.
Characterization of the Complexes
To find out the stoichiometry15 of the complexes, the percentage of the metal ions, anions
and CHN were determined. The molar conductance values reveal that all the complexes are
non-electrolytes. The CHN analyses are also in good agreement with the calculated values
(Table 1).
In the IR spectra16 of all the MBA complexes (Table 2), the stretching frequencies of
C=O and C-N-C bonds are found lowered showing that both carbonyl oxygen and CNC
nitrogen atoms are coordinated to the metal ions. So the ligand acts as ON donor. The IR
spectrum of the sulphato complexes shows the presence of coordinated sulphato group. The
bands at the ranges of 1150, 1000, and 900 cm-1 are due to ‘SO’ stretching mode, ν3 of
sulphato group. The triply degenerate ‘OSO’ bending mode, ν4 splits up into its components
at about 650, 600, and 580 cm-1 in the complexes. The frequencies at 750(ν1) and 500(ν2) are
also observed. These are due to the bidentate chelation17 associated with the coordinated

878 L. MURUGANANDAM et al.
sulphato group. The bands around 3300 - 3500, 1600 - 1650, 800 - 880, 600 - 690 and 460 -
530 cm-1 found only in the spectra of CoII, NiII, and CuII, sulphato complexes of MBA
indicate the presence of coordinated water molecule18.
Table 1. Analytical and Conductance Data for CoII, NiII, and CuII complexes of MBA.
% C
% H
% N
%Metal
%Anion
ΛM ohm-1
Complex
Obs.(Cal.) Obs.(Cal.) Obs.(Cal.) Obs.(Cal.) Obs.(Cal.) cm2 mol-1
30.48
(29.71)
42.00
3.05
(3.43)
4.61
5.81
(5.33)
7.85
10.77
(11.22)
8.13
24.12
(23.62)
12.54
Co(NO3)2.MBA
CoSO4.2MBA
21.39
31.44
(41.66)
(4.81)
(7.48)
(7.87)
(12.82)
29.97
(29.71)
3.31
(3.43)
5.46
(5.33)
11.05
(11.18)
23.78
(23.62)
Ni(NO3)2.MBA
20.97
33.12
(32.77)
41.59
(41.62)
3.98
(3.78)
3.92
(3.85)
6.09
(5.88)
5.23
(5.39)
13.25
(13.35)
12.53
(12.24)
25.84
(26.05)
18.37
(18.50)
Cu(NO3)2.MBA
15.06
08.95
CuSO4.MBA.2H2O
Table 2. Important IR Absorption Bands (cm-1) of MBA and of CoII, NiII, and CuII
complexes.
Compound
MBA
Co(NO3)2.MBA
νNH
νC=O νCNC
ν3
ν4
ν1
ν2
ν5
ν6
3297 1647 1116
3390 1598 1087
-
-
-
-
-
-
-
-
1313 1018 1429 824
CoSO4.2MBA
3337 1630 1099 1144
751
631
574
-
854 461
-
-
1099
984
Ni(NO3)2.MBA
Cu(NO3)2.MBA
3295 1622 1095
3548 1627 1101
-
-
1342 1028 1386 807
1310 1052 1384 802
-
CuSO4.MBA.2H2O 3485 1635 1109 1151
754
641
612
852
490
-
-
1109
987
The CoII nitrato complex exhibits electronic transition bands at 3841 cm-1 due to
4A2(F)→4T2(F)(ν1) transition, at 6719 cm-1 due to 4A2(F)→4T1(F)(ν2) transition,
15086 cm-1 due to 4A2(F)→4T1(P)(ν3) and the band at 28534 cm-1 due to charge
transfer19 transitions respectively. The calculated ν2/ν1 ratio is below 1.75. Also the
effective magnetic moment of nitrato complex is 4.58 B.M. These are the expected
values for tetrahedral geometry. The CoII sulphato complex exhibits electronic transition
4
bands at 6951(ν1), 14982(ν2), and 18576(ν3) cm-1 respectively due to T1g(F)→4T2g
4
4
(F)(ν1), T1g(F)→4A2g(F)(ν2), and T1g(F)→4T1g(P)(ν3) transitions20, respectively. The
band at 24053 cm-1 indicates the charge transfer transition. The calculated ν3/ν1 ratio for
CoII sulphato complex is 2.67. The μeff. value of this complex is 5.08 B.M. These are in
agreement with the values expected for an octahedral CoII complex. The number of
bands, their energy positions and intensity confirm the octahedral stereochemistry for
the sulphato complex.

Synthesis, Characterization and Antimicrobial Metal Complexes
879
3
The NiII nitrato complex exhibits a band at 3945 cm-1 due to T1g(F)→3T2g(F) transition,
3
3
another at 8446 cm-1 due to T1g(F)→3A2g(F) transition and also at 15107 cm-1 due to T1g
(F)→3T2g(P) transition21, respectively. The charge transfer transition bands occur at 24638 &
32471 cm-1. The calculated ν2/ν1 ratio is 2.14. The μeff. value of nitrato complex is 2.26 B.M.
The number of bands, their energy positions and intensity suggest tetrahedral stereochemistry.
Nitrato and sulphato complexes of CuII exhibit electronic absorption bands at 9204&9425 cm-1
due to B1g→2A1g and B1g→2A2g transitions respectively. The bands at 10388&12968 cm-1
2
2
corresponds to B1g→2B2gtransition. The bands at 11915&15317 cm-1 are due to Eg→2T2g(F)
transitions and those appearing at 24062, 32008&35100 cm-1 are characteristic of charge
transfer transitions22 (ligand→metal). The μeff. value of nitrato complex is 2.26 B.M. and for
sulphato complex is 1.83 B.M. The band positions and multi-component nature of the spectra
suggest a geometry for the sulphato complex and a tetragonally distorted tetrahedral geometry
for the nitrato complex respectively.
2
2
The electronic spectral parameters, Dq, B, β, β0% and ligand field stabilization energy
(LFSE)23, were calculated for CoII & NiII complexes. The order of Dq values among the CoII
complexes are found to be Co(NO3)2.MBA < CoSO4.2MBA. The Dq value for the
octahedral sulphato complex is greater than that of the tetrahedral CoII nitrato complex.
From the β0% value, the covalent character of CoII complexes is established. The percentage
covalency24 is more for the tetrahedral nitrato complex. The β0% values are about 29 and 13
for the nitrato and sulphato complex of CoII respectively, when the free ion value for the
inter electronic repulsion parameter is incorporated.
The X band EPR spectra25 of polycrystalline nitrato and sulphato complexes of CuII is
recorded at LNT (77 K). The g values of the, nitrato and sulphato complexes of CuII are in
the trend, g║ > g┴ > gDPPh suggesting that the unpaired electron lies predominantly in the dx2-
y2 orbital. The nitrato and sulphato complexes of CuII showed EPR spectra of axial symmetry
type indicating planar based distorted octahedral geometry around copper centre. The g║
values of nitrato and sulphato complexes are less than 2.30 indicating the covalent nature.
The higher g║ values may be due to the coordination of H2O to the CuII ion in these
complexes. The axial symmetry parameter26 G value, which is a measure of interaction
between the metal centers in the crystalline solids for the nitrato and sulphato complexes of
CuII, is 7.21 and 7.50. This suggests the lack of change in interaction between two CuII
centres in the unit cell of the complex.
The Cu(II) complex exhibited two quasireversible peaks. A cyclic voltammogram of
Cu(II) displays two reduction peaks, first one at Epc= -0.65 V with an associated oxidation
peak at Epa= -0.5 V and second reduction peak at Epc= -1.58 V with an associated oxidation
peak at Epa = -1.8 V. This corresponds to the Cu(II) / Cu(I) and Cu(I) / Cu(0) respectively at
a scan rate of 0.2 V/s. The value of ΔEp are 1.5 and 2.02 for first and second redox couples
respectively and increase with scan rate giving evidence for quasi-reversible nature
associated with one electron reduction.
Antibacterial Activity
A comparison of diameters of the inhibition zones of the compounds investigated and listed
in Tables 3 and 4 shows that CoII nitrato complex exhibits highest antibacterial and
antifungal activity against all the bacterial and fungal species studied. This is because, they
have larger diameters of inhibition zones than even the control gentamycin at the same
concentration and identical conditions. The complexes have more antibacterial and antifungal
activities than the ligand against all the bacteria and fungi studied. This observation clearly
indicates that the chelation increases the activity. The higher activity of the CoII complex may
be due to the fact that, Co(II) is an essential micronutrient during transcription and

880 L. MURUGANANDAM et al.
transformation of nucleic acids. CoII complexes were shown to inhibit cellular protein and
RNA synthesis. In CoII nitrato complex, the unsaturated metal center present, achieves higher
coordination number by binding with some of the functional groups of the protein. This leads
to the increased uptake of the compound by the bacterium and thereby inhibiting its growth.
Steric constraints are less for a tetrahedral complex than for an octahedral complex. So the
tetrahedral complexes are biologically more active than the octahedral complexes27.
Table 3. Antibacterial activity of ligand and its complexes.
P.
S.
Compound
E. coli
S.typhi
B. subtilis
S. aureus
aeruginosa
pyogenes
Conc.
(μg/disc)
Control
MBA
10 20 30 10 20 30 10 20 30 10 20 30 10 20 30 10 20 30
12 15 20 10 13 18 14 17 22 11 14 18 10 12 16 12 17 20
-
-
08 04 08 09 04 06 06
-
06 09 04 04 06
-
07 10
Co(NO3)2.
MBA
CoSO4.2
MBA
Ni(NO3)2.
MBA
Cu(NO3)2
.MBA
18 21 24 17 22 27 20 28 30 23 26 32 18 24 29 25 28 35
16 18 23 14 19 24 14 19 26 14 19 27 17 23 28 18 23 30
09 12 17 06 09 15 10 12 16 08 14 18 14 19 22 10 10 18
14 20 21 16 16 21 14 15 21 12 18 24 16 21 26 12 19 25
15 19 22 15 18 22 11 16 22 10 19 21 15 18 25 16 18 24
CuSO4.
MBA.2H2O
Table 4. Antifungal Activity of Ligand and its Complexes.
Compound
Conc. (μg/disc)
MBA
Co(NO3)2.MBA
CoSO4.2MBA
Ni(NO3)2.MBA
Cu(NO3)2.MBA
CuSO4.MBA.2H2O
A. niger
20
04
19
18
17
15
16
A. flavus
20
05
19
17
14
15
16
10
04
15
14
11
12
10
30
05
26
24
20
21
23
10
04
16
13
10
11
12
30
05
28
25
19
23
24
O
O
S
O
O
O
H2O
A
OH2
N
O
O
N
O
CH4
CH3
NH
CH3
NH
Figure 1. N-[Morpholino(phenyl)methyl]
Figure 2. A.SO4.MBA.2H2O (A=Cu ).
acetamide.

Synthesis, Characterization and Antimicrobial Metal Complexes
881
H3C
O
NH
O
S
ONO2
O2NO
O
O
O
Co
A
N
O
O
O
N
N
O
O
CH3
CH3
NH
NH
Figure 4. CoSO4.2MBA.
Figure 3. A.(NO3)2.MBA (A= Co, Ni and Cu).
Antifungal Activity
The fungi toxicity of the free ligand is less severe than that of the metal chelates. A possible
mechanism of toxicity may be speculated in the light of chelation theory28. Chelation
reduces considerably the polarity of the metal ion, mainly because of partial sharing of its
positive charge with donor groups and a possible π-delocalization of electron over the
chelate ring. This increases the liphophilic character of the neutral chelate, which favours its
permeation through lipoid layers of fungus membranes. Furthermore, the mechanism of
action of the compounds may involve the formation of hydrogen bond through the
uncoordinated heteroatoms viz. O, S, and N with the active centers of the cell constituents,
thus resulting in the interference with the normal cell process29. These compounds have a
greater chance of interaction with either the nucleotide bases or biologically essential metal
ions present in the biosystem and also coordinatively unsaturated metal present in the metal
complexes. The low activity of some of the complexes may be due to a mismatching of the
geometry and charge distribution around the molecule with that around the pores of the
fungal cell wall, preventing penetration and hence toxic reaction within the pores. As a
corollary, the complex cannot reach the desired site of action on the cell wall to interfere
with normal cell activity30.
References
1.
2.
3.
4.
5.
6.
7.
8.
9.
Kasim A N M, Venkappayya D, and Prabhu G V, J Indian Chem Soc., 1999, 67, 76.
Gandhi J B and Kulkarani N D, Polyhedron, 1999, 1735, 18.
Raman N and Ravichandran S, Asian J Chem., 2003, 255, 15.
Pelczar M J, Chan E C S, and Krieg R N, Microbiology, 5th Edn., (New York), 1998.
Haidne L, Coord Chem Rev., 1990, 253, 99.
Vogel A I, Quantitative Chemical Analysis, 6th Edn., 2004, 465.
Tramontini M and Angiolini L, Tetrahedron, 1990, 1791, 46.
Singh B, Singh R N and Aggarwal R C, Polyhedron, 1985, 401, 4.
Chohan Z H, Hassan M U I, Khan K M, and Supuran C T, J Enzyme Med Chem.,
2005, 183, 20.
10. Mishra A P and Srivastava S K, J Indian Council Chem.,1994, 2, 10.
11. Deshmuck M D, Orent J Chem., 1995, 185, 11.
12. Pandit L, J Indian Council Chem., 1995, 57, 11.
13. Seigel H and Martin R B, Chem Rev., 1982, 385, 82.
14. Yongsheng Hu, Zhaoxiang Wang, Hong Li, Xuejie Huang, and Liquan Chen, Int J
Mass Spectr., 2006, 251-264, 255.

882 L. MURUGANANDAM et al.
15. Kasuga N C, Yamamoto R, Hara A, Amano A, and Nomiya K, Inorg Chim Acta.,
2006, 4412, 359.
16. Nakamoto K, “Infrared and Raman spectra of inorganic and coordination
compounds”, 5th Edn., John Wiley & Sons, Toronto, Part B, 1997, 60.
17. Savinkina E, Albov D, Buravlev E and Zamilatskov I, Russian J Inorg Chem., 2007,
52, 7.
18. Parkin G, Chem Rev., 2004, 699, 104.
19. Cronin C F and Walton P H, Chem Commun., 2003, 1572.
20. Penner-Hahn J E, Indian J Chem (A), 2002, 13, 41.
21. Mondal A, Li Y, Khan M A, Ross J H and Houser R P, Inorg Chem., 2004, 7075, 43.
22. Klein E L, Khan M A and Houser R P, Inorg Chem., 2004, 7272, 43.
23. Szajna-Fuller E, Ingle G K, Watkins R W, Arif A M and Berreau L M, Inorg
Chem., 2007, 2353, 46.
24. Szajna E, Makowska-Grzyska M M, Wasden C C, Arif A M and Berreau L M,
Inorg Chem., 2005, 7595, 44.
25. Wertz J E and Bolton J R, “ESR Elementary Theory and Practical Applications”,
Chapman and Hall, New York, 1986.
26. Kimura E, Gotoh T, Aoki S, and Shiro M, Inorg Chem., 2002, 3239, 41.
27. FilionG J P, Zhenilo S, Salozhin S, Yamada D, Prokhortchouk E and Defossez P A,
Mol Cell Biol., 2006, 169, 26.
28. Hamers R and Casterman C H, J Med Biol., 1972, 166-170, 3.
29. Steiner T and Koellner G, J Mol Biol., 2001, 305, 535.
30. Eichhorn G L, Metal ions in Biological Systems, 1980, 10, 1.

International Journal of
Advances in
Organic Chemistry
International
International Journal of
International Journal of
Photoenergy
Medicinal Chemistry
Analytical Chemistry
Physical Chemistry
Hindawi Publishing Corporation
http://www.hindawi.com
Hindawi Publishing Corporation
Hindawi Publishing Corporation
http://www.hindawi.com
Hindawi Publishing Corporation
Hindawi Publishing Corporation
http://www.hindawi.com
Volume 2014
Volume 2014
http://www.hindawi.com
Volume 2014
http://www.hindawi.com
Volume 2014
Volume 2014
International Journal of
Carbohydrate
Chemistry
Journal of
Quantum Chemistry
Hindawi Publishing Corporation
Hindawi Publishing Corporation
http://www.hindawi.com
http://www.hindawi.com
Volume 2014
Volume 2014
Submit your manuscripts at
http://www.hindawi.com
Journal of
The Scientific
Analytical Methods
in Chemistry
World Journal
Hindawi Publishing Corporation
Hindawi Publishing Corporation
http://www.hindawi.com
http://www.hindawi.com
Volume 2014
Volume 2014
International Journal of
Journal of
Journal of
International Journal of
Bioinorganic Chemistry
Spectroscopy
Inorganic Chemistry
Electrochemistry
Applied Chemistry
and Applications
Hindawi Publishing Corporation
http://www.hindawi.com
Hindawi Publishing Corporation
Hindawi Publishing Corporation
Hindawi Publishing Corporation
Hindawi Publishing Corporation
Volume 2014
http://www.hindawi.com
Volume 2014
http://www.hindawi.com
Volume 2014
http://www.hindawi.com
Volume 2014
http://www.hindawi.com
Volume 2014
Journal of
Journal of
International Journal of
Chromatography
Journal of
Theoretical Chemistry
Catalysts
Research International
Chemistry
Spectroscopy
Hindawi Publishing Corporation
http://www.hindawi.com
Hindawi Publishing Corporation
http://www.hindawi.com
Hindawi Publishing Corporation
http://www.hindawi.com
Hindawi Publishing Corporation
http://www.hindawi.com
Hindawi Publishing Corporation
http://www.hindawi.com
Volume 2014
Volume 2014
Volume 2014
Volume 2014
Volume 2014