Journal of Molecular Liquids 215 (2016) 612–624
Contents lists available at ScienceDirect
Journal of Molecular Liquids
Spectroscopic, thermal and geometrical structures of Cu(II) azo
rhodanine complexes
b
c
A.Z. El-Sonbati a, , I.M. El-Deen , M.A. El-Bindary
⁎
a
Chemistry Department, Faculty of Science, University of Damietta, Damietta 34517, Egypt
Chemistry Department, Faculty of Science, University of Port Said, Port Said, Egypt
Engineering Chemistry Department, Higher Institute for Engineering and Technology, Damietta, Egypt
b
c
a r t i c l e i n f o
a b s t r a c t
Article history:
Copper(II) complexes of azo rhodanine (1–3) were prepared and characterized by elemental analyses, IR spectra,
X-ray diffraction, thermogravimetric analysis (TGA), molar conductance and magnetic susceptibilities as well as
mass spectra. The IR spectra showed that the ligands act as a monobasic bidentate coordinating via nitrogen atom
of −N = N− group and oxygen atom of enol form. The X-ray diffraction pattern of complex (2) is polycrystalline
phase. Quantum chemical parameters and geometric structural of the complexes were theoretically computed
and the results were studied. The alternating current conductivity (σac) and dielectric properties of Cu(II) com-
plexes (1–3) were investigated in the frequency range of 0.1–100 kHz and temperature range of 303–500 K.
The values of thermal activation energies of electrical conductivity (ΔE1 and ΔE2) for Cu(II) complexes are calcu-
lated and discussed. It was found that the electrical conductivity depends on the nature of substituents of the
complexes. The correlated barrier hopping (CBH) is the dominant conduction mechanism for all complexes.
© 2016 Elsevier B.V. All rights reserved.
Received 7 October 2015
Received in revised form 19 December 2015
Accepted 1 January 2016
Available online xxxx
Keywords:
Copper(II) complexes
X-ray diffraction analysis
Quantum chemical parameters
Dielectric properties
Ac conductivity
1. Introduction
complexes in the range of 0.032–0.164 eV for ΔE1 and 0.170–0.488 eV
for ΔE2 depending on the test frequency and change of substituents
Azo rhodanine derivatives have played an important role in the de-
velopment of coordination chemistry as they readily form stable com-
plexes with most transition metals [1–5]. The variety of coordination
modes of azo rhodanine derivatives has been demonstrated in a number
of complexes. Their biological applications have considerable interest
[4,6]. Rhodanine azo dyes appear to be very important as chelating
agents as far as a large number of metal ions is concerned [1,4], probably
via incorporation of the N\\C_S moiety, the importance of which has
been stressed in many fungicides and bactericides [7]. Azo rhodanine
and its derivatives contain hetero atoms which are considered to be ad-
sorption centers (nitrogen, sulfur, oxygen) and could be used as anti-
corrosion agents for protection of metals [8].
for complexes affects the thermal properties and conductivities of the
complexes. The ligand of 5-(2,3-dimethyl-1-phenylpyrazol-5-one
azo)-2-thioxo-4-thiazolidinone ligand (HL) and its metal complexes
with copper(II), cobalt(II) and nickel(II) have been studied the thermal,
dielectric properties and ac conductivity. In addition the effect of metal
ion variation on the thermal activation energies of decomposition, ther-
mal activation energies of electrical conductivity and conduction mech-
anism was discussed [11].
In continuation to our previous work [9–11], we prepare Cu(II) com-
plexes of some azo rhodanine derivatives. The Cu(II) complexes are sub-
jected to elemental analyses, thermal analysis, molar conductance and
magnetic measurements for the purpose of structural elucidation.
Mass spectrum and X-ray diffraction analysis of Cu(II) complex (2) is
discussed. The ac conductivity, dielectric properties, conduction mecha-
nism and effect of substituents of Cu(II) complexes (1–3) on these prop-
erties are discussed, as well as the thermal analysis (TGA and DTG)
studies.
The dielectric properties and alternating current conductivity (σac
)
of azo rhodanine and its derivatives and their metal complexes were in-
vestigated [9–11]. It was found that the thermal activation energies of
electrical conductivity, ΔE1 and ΔE2, increase according to the following
order p-(NO2 b H bCH3 b OCH3) dependent on the structure of the com-
pounds and the correlated barrier hopping (CBH) is the dominant con-
duction mechanisms for azo rhodanine and its derivatives [9]. El-
Ghamaz et al. [10] investigated the alternating current conductivity
(σac) and dielectric properties of complexes and it was found that the
values of the thermal activation energies of electrical conductivity for
2. Experimental
Aniline (99.5%), 4-derivatives anilines (alkyl: OCH3 (99.0%), NO2
(97.0%) and 2-thioxo-4-thiazolidinone (98.0%); Aldrich Chemical Com-
pany were used without any further purification. CuCl2.2H2O (Sigma)
and organic solvents were spectroscopic pure from British Drug House
(BDH) included ethanol, methanol and dimethyl formamide.
⁎
Corresponding author.
0167-7322/© 2016 Elsevier B.V. All rights reserved.