Synthesis, XRD, EXAFS and XANES study of Cu(II) complexes of aniline dithiocarbamate

Article abstract of DOI:10.14233/ajchem.2020.22456

In present investigation, seven copper(II) complexes were synthesized using various aniline dithiocarbamate. The synthesized Cu(II) complexes were studied for different structural and chemical parameters using XRD, EXAFS and XANES. The output obtained fro

Full text of DOI:10.14233/ajchem.2020.22456

Asian Journal of Chemistry; Vol. 32, No. 3 (2020), 627-633
A
SIAN
J
OURNAL OF HEMISTRY
C
https://doi.org/10.14233/ajchem.2020.22456
Synthesis, XRD, EXAFS and XANES Study of Cu(II) Complexes of Aniline Dithiocarbamate
1,*
2
3
ANURAG GEETE , B.D. SHRIVASTAVA and ASHUTOSH MISHRA
1Department of Physics, Shri Rewa Gurjar Bal Niketan College, Sanawad, Khargone-451111, India
2Department of Physics, Maharaja Bhoj Government P.G. College, Dhar-454001, India
3School of Physics, Devi Ahilya University, Indore-452001, India
*Corresponding author: E-mail: anuraggeete.21@gmail.com
Received: 17 September 2019;
Accepted: 5 November 2019;
Published online: 31 January 2020;
AJC-19770
In present investigation, seven copper(II) complexes were synthesized using various aniline dithiocarbamate. The synthesized Cu(II)
complexes were studied for different structural and chemical parameters using XRD, EXAFS and XANES. The output obtained from
X-ray studies was synthesized using Athena and Origin 6.0 software. The results of the investigation were used in determining the
structures of the synthesized complexes. The particle size of the synthesized complexes ranged between 46.7 and 125.3 nm. The lattice
constant of Cu(II) complexes was found 3.61-3.62 Å.
Keywords: Aniline dithiocarbamate, Cu(II) complex, EXAFS, Ligands, XRD, XANES.
are easily prepared, a wide range of chemistry has been deve-
loped. Complexes of dithiocarbamate ligands like dithiocar-
bamate themselves have practical applications in agriculture and
in the synthesis of adducts, nanoparticles and nanocomposites
[7,8]. Recently gold(III) dithiocarbamate complexes have been
prepared and used for treatment of human cancer by suppress
tumor growth via direct inhibition of the proteasome activity
[9]. Transition metal complexes with mixed ligands, S and N
as donor atoms have found great interest among other coordi-
nation complexes [10-12]. Considering these facts, present
study was conducted to synthesize copper(II) complexes with
aniline dithiocarbamate ligands and their properties were studied
using XRD, EXAFS and XANES techniques.
INTRODUCTION
Copper is a soft, malleable and ductile metal with very
high thermal and electrical conductivity [1]. Copper is used
as a conductor of heat and electricity, as a building material
and as a constituent of various metal alloys, such as sterling
silver used in jewellery, cupronickel used to make marine
hardware and coins and constantan used in strain gauges and
thermocouples for temperature measurement [2,3]. Copper
compounds, whether organic complexes or organo-metallics,
promote or catalyse numerous chemical and biological pro-
cesses. Copper forms coordination complexes with ligands [4].
In aqueous solution, copper(II) exists as [Cu(H2O)6]2+. This
complex exhibits the fastest water exchange rate (speed of
water ligands attaching and detaching) for any transition metal
aquo complex. Compounds that contain a carbon-copper bond
are known as organocopper compounds [4]. They are very
reactive towards oxygen to form copper(I) oxide and have
many uses in chemistry. Copper(I) forms a variety of weak
complexes with alkenes and carbon monoxide, especially in
the presence of amine ligands [5,6].
EXPERIMENTAL
Preparation of ligands: In present investigation chloro
aniline dithiocarbamate, nitro aniline dithiocarbamate, fluoro
aniline dithiocarbamate and toluidine dithiocarbamate ligands
were synthesized and used as complexing agent for Cu(II).
The ligands were prepared by adding 0.01 M of anilines to 0.016
M solution of NaOH in 15 mL distilled water with continuous
stirring [13,14]. The mixture was refluxed for 2 h and further
it was cooled in ice. The ligands were precipitated by drop
Dithiocarbamates were discovered as a class of chemical
compounds in the history of organosulfur chemistry. These are
a versatile class of monoanionic 1,1-dithio ligands and as they
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628 Geete et al.
Asian J. Chem.
wise addition of carbon disulphide. The formed ligands were
extracted by ether, filtered, washed with acetone and dried in
vacuum.
EXAFS and XANES studies: The XANES study was
carried out using synchrotron radiation beam line (BL-08) of
the Indus-2 [15]. All the samples have been studied in powder
form. The EXAFS studies of copper complexes were carried
out and from the position of maxima and minima, bond lengths
have been estimated using various methods viz., Levy’s, Lytle’s,
LSS (Levy, Sayers and Stern) and Fourier Transform (FT) [16].
The XANES results of Cu(II) complexes viz. chemical shift,
shift of absorption maximum and edge structure have been
provided. The analysis EXAFS and XANES results were carried
out using Athena and Origin 6.0 software.
Synthesis of Cu(II) complexes: Copper(II) complexes
with dithiocarbamates were prepared by mixing 1:2 molar
quantities of metal salt and ligand. The copper salt (CuSO4)
was dissolved in distilled water and dithiocarbamate was dis-
solved in ethanol [13,14]. The two solutions were mixed with
continuous stirring. The complex produced in the form of
precipitate was filtered off, washed with acetone and water in
equal quantities (1:1). The product was dried in vacuum. The
fine powder of the formed complexes was used for further
analytical studies.
RESULTS AND DISCUSSION
XRD studies: XRD measurements were obtained by using
Bruker D8 Advance X-ray diffractometer. Monochromatic
X-rays, in an exceedingly narrow, well-collimated beam were
used. The X-rays were created employing a sealed tube and
the wavelength of X-rays was 1.54 Å [15]. The results of all
the copper(II) complexes were interpreted using Origin 6.0
software.
XRD of Cu(II) complexes: The X-ray diffraction data
of copper(II) complexes are given in Fig. 1. The X-ray pattern
have been indexed by using computer software and applying
interactive trial and error method keeping in mind the charac-
teristic of the various symmetry system, till a good fit was
obtained between the observed and the calculated in 2θ values.
3000
300
3000
Cu-1
Cu-2
Cu-3
2500
2000
1500
1000
500
250
200
150
100
50
2500
2000
1500
1000
500
0
0
0
10
20
30
40
50
60
70
10
20
30
40
50
60
10
20
30
40
50
60
2
θ
(°)
2
θ
(°)
2θ (°)
3000
2500
2000
1500
1000
500
700
600
500
400
300
200
100
0
1400
1200
1000
800
600
400
200
0
Cu-4
Cu-5
Cu-6
0
10
20
30
40
50
60
70
10
20
30
40
50
60
70
10
20
30
40
50
60
2
θ
(°)
2
θ
(°)
2θ (°)
2500
2000
1500
1000
500
Cu-7
0
10
20
30
40
50
60
2θ (°)
Fig. 1. XRD spectra of synthesized copper(II) complexes

Vol. 32, No. 3 (2020)
Synthesis, XRD, EXAFS and XANES Study of Cu(II) Complexes of Aniline Dithiocarbamate 629
The unit cell parameters were calculated from the indexed data
[13]. The observed values are good fit for tetrahedral to give
lattice constant that have been found to be the tetrahedral type
(Table-1). The experimental value of density of the ligand and
complex determined has been found to be in good agreement
within the limits of the experimental error. In XRD analysis,
total 20, 16 and 12 diffractograms and XRD spectra record
for copper complexes are shown in Fig. 1. Comparison values
revealed that there was good agreement between values of 2θ
and d-values. The powder X-ray diffraction data showed iden-
tical features with very poor crystallinity. The patterns were
qualitative and dispersive in intensity for copper metal comp-
lexes. The results of several researchers [15-17] are in good
agreement with the present findings.
Suggested structures of Cu(II) complexes: Based upon
the XRD investigation of the synthesized Cu(II) metal comp-
lexes. The structures of the complexes have been suggested
and presented in Fig. 2.
EXAFS and XANES investigation of Cu(II) complexes:
The chemical shift ∆Ek ranged 8.3-9.5 for Cu(II) complexes
synthesized with aniline/toluidine dithiocarbamate ligands
(Table-2). Similarly, the edge width ranged between 10.3 and
12.7 eV for different complexes under study whereas the edge
width for Cu(II) metal was found 14.5 eV (Fig. 3). Similar
findings were recorded by several researchers [15-17].
The wave factor (k) data for various complexes at various
n has been shown in Table-3. The wave factor (k) ranged 1.55-
5.0 Å at initial stage. It was found 4.55-4.7 Å at second level
of n. The EXAFS maxima and minima at the k-absorption
edge of Cu(II) has been reported for four different levels of Q
and presented in Table-4. The EXAFS maxima and minima at
the k-absorption edge ranged 18.61-21.43 and 39.48-49.06
eV, respectively for Q = 2.04 (Fig. 4-6). The EXAFS investi-
gation was used for determining the bond length of Cu(II)
complexes. The obtained data was processed in Athena and
Origin 6.0 software. The bond length was determined by four
different methods viz. LSS, FT, Lytle and Levy and shown
in Table-5. The bond length of various Cu(II) complexes
synthesized using aniline/toluidine dithiocarbamate ligands
calculate by LSS, FT, Lytle and Levy methods were ranged
1.38-2.81, 1.01-2.97, 1.61-2.02 and 1.26-3.75 Å, respectively.
All the methods employed for determing the bond length
showed the similar trend for all seven complexes studied.
The binding energies for 1s electron of Cu atom in diffe-
rent oxidation stage (+1 to +6) and shift in binding energy has
been presented in Table-6. The data revealed that the shift in
binding energy ranged 8.59-130.72 eV for +1 to +6 oxidation
stage of Cu atom (Fig. 6). Similar findings were also recorded
by researchers previously [15-17].
TABLE-1
PARTICLE SIZE AND LATTICE CONSTANT F SYNTHESIZED COPPER(II) COMPLEXES
Complex name
m.f.
Cu(C7H4S2NCl)2
Cu(C8H7NS2)2
Cu(C7H4N2S2O2)2
Cu(C7H4S2NF)2
Cu(C7H4S2NCl)2
Cu(C7H4N2S2O2)2
Cu(C8H7NS2)2
Particle size (nm)
Lattice constant (Å)
[Cu(o-chloroaniline dithiocarbamate)2] (Cu-1)
[Cu(o-toluidine dithiocarbamate)2] (Cu-2)
[Cu(o-nitroaniline dithiocarbamate)2] (Cu-3)
[Cu(4-fluoroaniline dithiocarbamate)2] (Cu-4)
[Cu(p-chloroaniline dithiocarbamate)2] (Cu-5)
[Cu(p-nitroaniline dithiocarbamate)2] (Cu-6)
[Cu(p-toludinedithiocarbamate)2] (Cu-7)
46.7
69.4
65.4
69.4
125.3
73.7
48.9
3.62
3.62
3.62
3.61
3.62
3.61
3.61
S
S
S
S
S
S
S
S
S
S
Cu2+
Cu2+
Cu2+
N
N
N
N
N
N
S
S
Cl
Cl
O2N
NO2
H3C
CH3
Cu-1
Cu-3
Cu-2
S
S
S
S
S
S
S
S
S
S
S
S
Cu2+
Cu2+
Cu2+
N
N
N
N
N
N
Cl
Cl
F
F
NO2
NO2
Cu-5
Cu-4
Cu-6
S
S
S
S
Cu2+
N
N
CH3
CH3
Cu-7
Fig. 2. Suggested structures of synthesized copper complexes

630 Geete et al.
Asian J. Chem.
TABLE-2
XANES DATA FOR K-ABSORPTION EDGE OF COPPER MIXED LIGAND COMPLEXES
Chemical shift
Shift of the principal
Absorption maximum (eV)
Edge-width
(EA-Ek) (eV)
14.5
Complex
Ek1 (eV)
EA (eV)
ENC
∆Ek= (Ecomplex-Emetal) (eV)
Cu metal
Cu-1
Cu-2
Cu-3
Cu-4
Cu-5
Cu-6
Cu-7
8980.5
8990.0
8988.8
8989.6
8989.5
8988.6
8989.5
8989.0
8995.0
9001.5
8999.2
9002.3
9001.6
8998.9
9001.1
8999.5
–
–
–
9.5
8.3
9.1
9.0
8.1
9.0
8.5
0.67
0.70
0.75
0.80
0.82
0.84
0.86
6.5
4.2
7.3
6.6
3.9
6.1
4.5
11.5
10.4
12.7
12.1
10.3
11.6
10.5
2.0
1.5
1.0
0.5
0.0
1.8
3
2
1
0
Cu-1
Cu-2
Cu-3
1.5
1.2
0.9
0.6
0.3
0.0
9000
9200
Energy (E)
9400
9600
9000
9200
Energy (E)
9400
9600
9800
9800
8800
9000
9200
Energy (E)
9400
9600
1.6
1.2
0.8
0.4
0.0
2.4
1.8
1.2
0.6
0.0
2.0
Cu-4
Cu-5
Cu-6
1.5
1.0
0.5
0.0
8800
9000
9200
Energy (E)
9400
9600
9800
8800
9000
9200
Energy (E)
9400
9600
8800
9000
9200
Energy (E)
9400
9600
9800
1.2
0.9
0.6
0.3
0.0
-0.3
Cu-7
8800
9000
9200
9400
9600
Energy (E)
Fig. 3. Normalized µ(E) versus E spectra of Cu(II) complexes
TABLE-3
WAVE VECTOR k (Å-1) FOR EXAFS MAXIMA AND MINIMA AT THE K-ABSORPTION
EDGE OF COPPER(II) COMPLEXES AND THEIR CORRESPONDING VALUES OF n
k (Å-1)
Cu-4
2.85
4
5.55
6.2
6.85
7.3
8.15
8.45
9.1
9.7
10.2
10.7
n
Cu-1
5.0
6.3
6.9
7.5
Cu-2
3.8
4.25
4.8
6.25
6.9
7.5
8.2
8.5
9.15
9.75
10.25
10.7
Cu-3
3.75
4.1
4.55
5.35
5.65
6.45
6.95
7.5
8.2
8.5
9.15
9.75
Cu-5
1.95
2.95
3.75
4.25
4.8
6.25
6.9
7.5
8.2
8.5
9.15
9.65
Cu-6
Cu-7
2.4
3.4
4.7
5.7
6.85
7.45
8.2
0
1
2
3
4
5
6
7
8
1.55
3.1
4.7
6.4
6.85
7.3
8.15
9.75
11.2
–
8.2
8.5
9.15
9.65
10.25
10.7
11.25
–
9.6
10.2
10.7
11.2
12.1
9
10
11
–
–

Vol. 32, No. 3 (2020)
Synthesis, XRD, EXAFS and XANES Study of Cu(II) Complexes of Aniline Dithiocarbamate 631
TABLE-4
ENERGY E (eV) FOR EXAFS MAXIMA AND MINIMA AT THE K-ABSORPTION EDGE OF
COPPER(II) COMPLEXES THEIR CORRESPONDING VALUES OF ENERGY LEVEL Q
Structure
Q
2.04
–
6.04
–
12.00
–
20.00
–
Cu-1
20.86
41.17
Cu-2
18.61
39.48
Cu-3
21.43
40.04
62.6
118.4
149.4
168.07
189.5
215.44
Cu-4
21.43
49.06
64.29
159.04
191.76
215.4
266.7
285.9
Cu-5
18.61
39.48
63.16
158.48
192.32
215.4
266.7
285.9
Cu-6
20.86
49.06
63.73
158.48
192.32
223.9
266.7
285.9
Cu-7
21.43
49.06
63.73
74.44
97.57
117.87
191.76
223.9
A
α
B
β
C
γ
D
δ
63.73
63.16
159.04
192.32
216.01
266.77
285.94
158.48
192.32
223.9
266.77
285.94
30
15
10
5
Cu-1
Cu-2
Cu-3
20
10
10
5
0
0
0
-10
-20
-30
-5
-5
-10
-10
0
2
4
6
8
k (Å)
10
12
14
-2
0
2
4
6
k (Å)
8
10
12
14
0
2
4
6
k (Å)
8
10
12
1.5
3
2
4
2
Cu-4
Cu-5
Cu-6
1.0
0.5
1
0
0
-2
-4
-6
-8
0.0
-1
-2
-3
-0.5
-1.0
-2
0
2
4
6
8
10
12
14
-2
0
2
4
6
8
10
12
-2
0
2
4
6
8
10
12
14
k (Å)
k (Å)
k (Å)
12
10
8
Cu-7
6
4
2
0
-2
-4
-6
-8
-2
0
2
4
6
8
10
12
14
k (Å)
Fig. 4. k2χ(k) versus k spectra of Cu(II) complexes
TABLE-5
VALUES OF FIRST SHELL BOND LENGTHS (Å)
CALCULATED FROM LSS AND FOURIER TRANSFORM
METHODS FOR COPPER(II) COMPLEXES
TABLE-6
BINDING ENERGIES OF 1s ELECTRONS OF COPPER
ATOM IN DIFFERENT OXIDATION STATES
Oxidation
state
Electronic
B.E. of 1s
Shift in
Shift in
B.E. (eV)
Phase uncorrected first shell radial distance R (Å)
configuration electrons (au) B.E. (au)
Name of
complex
LSS
method
2.65
2.38
2.81
2.27
2.19
1.38
1.76
Fourier transform
Lytle
method
1.62
1.61
1.97
1.62
1.61
1.62
2.02
Levy
method
1.26
0
3d10 4s1
3d10 4s0
3d9 4s0
3d8 4s0
3d7 4s0
3d6 4s0
3d5 4s0
328.79173
329.10745
329.76836
330.55359
331.45117
332.48020
333.59556
–
–
8.59
method
2.76
2.94
2.97
2.88
1.99
1.01
1.85
+1
+2
+3
+4
+5
+6
0.3157
0.9766
1.7618
2.6594
3.6884
4.8038
Cu-1
Cu-2
Cu-3
Cu-4
Cu-5
Cu-6
Cu-7
26.57
47.94
72.37
100.37
130.72
1.26
1.64
1.26
1.26
1.26
3.75

632 Geete et al.
Asian J. Chem.
0.6
0.5
0.4
0.3
0.2
0.1
0.0
6
5
4
3
2
1
0
3.0
2.5
2.0
1.5
1.0
0.5
0.0
Cu-1
Cu-2
Cu-3
0
2
4
6
8
10
0
2
4
6
8
10
0
2
4
6
8
10
R (Å)
R (Å)
R (Å)
R (Å)
R (Å)
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
14
12
10
8
2.0
1.5
1.0
0.5
0.0
Cu-4
Cu-5
Cu-6
6
4
2
0
0
2
4
6
8
10
0
2
4
6
8
10
0
2
4
6
8
10
R (Å)
R (Å)
3.0
2.5
2.0
1.5
1.0
0.5
0.0
Cu-7
0
2
4
6
8
10
Fig. 5. Magnitude of Fourier transform of the χ(k) versus k spectra of Cu(II) complexes
300
250
200
150
100
50
300
Cu-1
Data1B
200
180
160
140
120
100
80
Cu-3
Data1 Cu-3
Cu-2
Data1 Cu-2
250
200
150
100
50
60
40
20
0
0
0
0
2
4
6
8
10 12 14 16 18 20 22
Q
0
2
4
6
8
10 12 14 16 18 20 22
Q
0
2
4
6
8
10 12 14 16 18 20 22
Q
300
300
250
200
150
100
50
300
250
200
150
100
50
Cu-5
Data1 Cu-5
Cu-4
Data1 Cu-4
Cu-6
Data1 Cu-6
250
200
150
100
50
0
0
0
0
2
4
6
8
10 12 14 16 18 20 22
Q
0
2
4
6
8
10 12 14 16 18 20 22
Q
0
2
4
6
8
10 12 14 16 18 20 22
Q
200
180
160
140
120
100
80
Cu-7
Data1 Cu-7
60
40
20
0
0
2
4
6
8
10 12 14 16 18 20 22
Q
Fig. 6. E vs. Q plot of Cu(II) complexes

Vol. 32, No. 3 (2020)
Synthesis, XRD, EXAFS and XANES Study of Cu(II) Complexes of Aniline Dithiocarbamate 633
6. T.C. Pleger, Proceedings of Twenty-Seventh Annual Meeting of the
Forest History Association of Wisconsin, Oconto, WI, vol. 5, pp. 10-18
Conclusion
The seven copper [Cu(II)] complexes synthesized using
various dithiocarbamate ligands. The XRD, EXAFS and
XANES investigation of copper [Cu(II)] complexes revealed
that the particle size of synthesized complexes ranged between
46.7 and 125.3 nm. The lattice constant of Cu(II) complexes
was found 3.61-3.62 Å. The synthesized metal complexes
behaved as symmetric bidendate ligand during complexation
and carry no charge and were found thermally stable.
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CONFLICT OF INTEREST
The authors declare that there is no conflict of interests
regarding the publication of this article.
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