Abstract: 1-Phenyl-4-(2&apos;-hydroxyphenyl-1-yl)di-imino azine, {1P-4-(2&apos; HPDA)} 1, 4(2&apos;-hydroxyphenyl-1-yl)di-imino azine, {1, 4-(2&apos; HPDA)} are derived from benzophenone hydrozone with different aldehydes in presence of few drops of concentrated hydrochloric acid in alcoholic medium. Metal(II) complexes have been prepared by salts of CoCl 2 , CuCl 2 , NiCl 2 and CdCl 2 reacting with azine ligands dissolved in alcohol in the molar ratio of (1:2). The prepared complexes were characterized by using various physical methods viz. elemental, molar conductance, magnetic susceptibility, IR, NMR, XRD and UV-Visible. Conductivity of the powder samples were measured by two probe method. Measured electrical conductivities of Co(II), Cu(II), Ni(II) and Cd(II) complexes of azines are reported in this paper. It is found that at room temperature these complexes show insulator behavior. At higher temperature conductivity increases linearly, showing semi conducting behavior

C Basavaraja

M Revanasiddappa

S C Raghavendra

S D Angadi

Syed Khasim

T Suresh

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ISSN: 0973-4945;   CODEN   ECJHAO 
  E-Journal of Chemistry 
http://www.e-journals.net                                          Vol. 5, No.4, pp. 797-801, October 2008 
Electrical Conductivity Studies on Co(II), Cu(II), 
Ni(II) and Cd(II) Complexes of Azines 
M. REVANASIDDAPPA
*
, SYED KHASIM
§
, S. C.
 
RAGHAVENDRA
#
, 
 C. BASAVARAJA
‡
, T. SURESH
¶
 and S. D. ANGADI
†
 
*
Department of Chemistry, 
§
Department of Physics,  
#
Department of Electronics and Communications,  
PES School of Engineering,  Bangalore - 560 100, Karnataka, India. 
¶
Department of Chemistry, 
 Gulbarga University P G  Center, Bellary -583 104, Karnataka, India. 
†
Department of Studies in Chemistry,  
Gulbarga  University, Gulbarga- 585 106, Karnataka, India. 
 ‡
Department of Chemistry, Inje University, Kimhae – 621749, South Korea. 
revum@rediffmail.com 
Received 21 November 2007; Accepted 20 January 2008 
Abstract: 1-Phenyl-4-(2'-hydroxyphenyl-1-yl)di-imino azine, {1P-4-(2' 
HPDA)} 1, 4(2'-hydroxyphenyl-1-yl)di-imino azine, {1, 4-(2' HPDA)} are 
derived from benzophenone hydrozone with different aldehydes in presence of 
few drops of concentrated hydrochloric acid in alcoholic medium. Metal(II) 
complexes have been prepared by salts of CoCl2, CuCl2, NiCl2 and CdCl2 
reacting with azine ligands dissolved in alcohol in the molar ratio of (1:2). The 
prepared complexes were characterized by using various physical methods viz. 
elemental, molar conductance, magnetic susceptibility, IR, NMR, XRD and 
UV-Visible. Conductivity of the powder samples were measured by two probe 
method. Measured electrical conductivities of Co(II), Cu(II), Ni(II) and Cd(II) 
complexes of azines are reported in this paper. It is found that at room 
temperature these complexes show insulator behavior. At higher temperature 
conductivity increases linearly, showing semi conducting behavior.    
Keywords: Electrical conductivity, Complexes of Azines, Benzophenone hydrozone  
Introduction 
One of the most interesting areas of research is that of electrically conducting 
organometallic polymers
1-2
. The method of choice for producing conducting organometallic 
polymers    involves    complexing   transition   metals   with   conjugated   bridging  ligands.    
Electrical Conductivity Studies on Complexes of Azines 798 
The ability to alter the oxidation state of the metal ion, and thus the charge density along the 
polymer backbone, provides an alternative route to charge carrier creation as opposed to 
redox doping. Polyamides and their poly chelates have σ values at 298K of about 10
– 6
-10
-11
 
ohm
-1 
cm
-1
. The temperature dependant σ has a typical break point at 410- 450 K with lower 
∆E values at higher temperature Marcu and Dima
3
 have prepared the polymers of dimethyl–
4,4'–[p–phenylene–bis (methylidene nitrilo)] disalicylate with Co(II), Ni(II) and Cu(II) in 
DMF and reported that these polymers are heat stable, semi conducting in nature.  Semis 
conducting properties of poly chelates 2, 5–dihydroxy phthaldehyde and series of di and 
tetra amino compounds and monomaric Schiff bases and their chelates have been reported
4
.  
Coordination polymers of Cu(II) and Ni(II) with ethylene diaminetetrahalato and tetra 
thioazalatotetrathio flavane were prepared and their electrical conductivity has been studied
5-7
. 
In view of the above discussion, the present work deals with electrical conductivity studies 
on Co(II), Cu(II), Ni(II) and Cd(II) complexes of azines derived from benzophenone 
hydrozone with different aldehydes in presence of few drops of concentrated hydrochloric 
acid in alcoholic medium. 
Experimental 
Preparation of {1P-4-(2' HPDA)} and {1, 4-(2' HPDA)} 
1-Phenyl-4-(2'-hydroxyphenyl-1-yl)di-imino azine, {1P-4-(2'-HPDA)} [Mol Formula 
C14H12N2O2, Yield=70%, M.P=216ºC ], 1,4(2'-hydroxyphenyl-1-yl) di-imino azine,{1, 4-(2' 
HPDA)} [Moleuclar formula C14H12N2O, yield=75%, m.p=187ºC] were derived from 
benzophenone hydrozone with different aldehydes in presence of few drops of concentrated 
hydrochloric acid in alcoholic medium has been reported in the literature
8
.  
Preparation of complexes 
Metal complexes of azines were synthesized by adding 0.002 mole of ligand solute ion in 
ethanol and little quantity of dimethyl formamide to 0.001 mole of alcoholic solution 
metal(II) chloride.  The contents were refluxed for about 3-4 hours on a water bath.  Then 
the sodium acetate was added and continued refluxation for half an hour, allowed to cool 
and the reaction mixture was transferred into a beaker and the precipitation of the complex 
was initiated by adding distilled water.  The precipitate was filtered, washed with alcohol 
and dried over fused calcium chloride.  
Electrical measurement 
The powdered complex was palletized isostatistically in a steel disk of specific diameter 
under pressure of 5 – 6 tons per cm
2
 with the help of hydraulic press; the pellet thus 
obtained was crack free and hard. These pellets were coated with silver paste to make 
good electrical contacts. The resistance of the pellets were measured on   BPL – INDIA 
million mega meter R M 160 m K IIIA and D C micro voltmeter by voltage drop 
method
9
.  
Results and Discussion 
The prepared complexes were characterized by using various physical methods viz. 
elemental, molar conductance, magnetic susceptibility, IR, NMR, XRD and UV-Visible. All 
these data reveals that the formation of metal complexes through the donor sites of O- and 
N-atoms
7
.  The measurements of DC resistivity of the complexes were carried out in the 
temperature range of 404 - 540 K.  
 
799 M  REVANASIDDAPPA et al. 
 The DC transport measurements were made on three samples as a function of temperature, 
at 330 – 380 K and the results were indicated in Figure 1- 4. The logarithmic conductivity 
increases linearly with temperature. It was found that conductivity increases with increasing T 
and decreasing as T
-1 / 4
. Whenever an electron moves in an electric field which is disordered, 
as in an amorphous solid and semiconductor, some or all the electrons will be localized 
depending on the degree of disorder. The conductivity variation with increasing temperature in 
a material with partial localization of carriers changes from T
 -1 
behavior to T 
-1/ n
 at low 
temperatures
10
. Accordingly, the mechanism of electrical conduction can be distinguishing as 
follows: (a) conduction due to carriers excited beyond the mobility shoulders into non-
localized or extended states; (b) into the localized states at the band edges; (c) hopping 
(tunneling) between localized states near the Fermi energy. Therefore, the overall conductivity 
of the material in the finite temperature range can be written as:          
σ Overall = σ ext + σ hop                                       (1) 
1 . 8 5 1 . 9 0 1 . 9 5 2 . 0 0 2 . 0 5 2 . 1 0
- 1 9 . 7
- 1 9 . 6
- 1 9 . 5
- 1 9 . 4
- 1 9 . 3
- 1 9 . 2
- 1 9 . 1
- 1 9 . 0
 
 
ln
 σ
1 / T 1 0
- 3
K
- 1
[ N i { 1 P - 4 - ( 2 ' - H P D A ) } ]
2
2 H
2
O
 
Figure 1. Temperature dependence of electrical conductivity 
(The electrical conductivity of Ni[{1P-4-(2' HPDA)}]2 2H2O  varies from 4.857x10
–5  
 
mhos/cm to 2.749 x10
–5 
mhos /cm over the temperature range 474-528 K) 
 At relatively high temperatures, the phonon energy will be very high compared to the 
energy gap between the nearest neighbor states at EF. Hence the contribution to conduction 
by hopping will be considered is thermal excitation of carriers. The conductivity σext  
variation with T is expressed by Arrhenius relation of the type 
σ ext =  σ M  exp   




 ∆−
kT
E       (2) 
 Where σ M is the pre-exponential constant corresponding to 1/T = 0, ∆ E the activation 
energy for electron transfer and k the Boltzmann’s constant. The activation energy ∆ E in eq (2) 
is found to be from Figure 3. The pre-exponential in the conductivity eq (2) is represented as: 
σ M = σ o exp (-γ )                     (3) 
 Where  σ o   is the minimum conductivity at T = 0 of a metal below which undergoes a 
transition in to an insulator. The value of σ o for 3D conduction has been predicated to be 
~ 0.03 e
2
 / ha, where ‘a’ is the lattice constant, ‘e’ is the electron charge and ‘h’ the 
Plank’s   constant. As   shown  in  Figure  4  the   hopping    conductivity  σ hop  vary   with  
Electrical Conductivity Studies on Complexes of Azines 800 
temperature of   T
-1 / 4
. This type of transport behavior is called as variable range hopping 
or phonon assisted quantum mechanical tunneling
10
. Since the hops are phonon assisted, 
the hopping conductivity has a finite value at a finite temperature. The conductivity 
variation in this region can be expressed as:                                                                                                           
σ hop = A exp (- B T 
-1/ n
)                   (4) 
Where ‘A’ is the pre-exponential factor which depends on the hopping distance, phonon 
frequency and the density of states(DOS) at EF , N(EF ); and  B=
4/1
F
3
)E(kN





 α a constant 
depending on the random potential well decay length (α -1) and N (EF).  
2 . 0 0 2 . 0 5 2 . 1 0 2 . 1 5 2 . 2 0 2 . 2 5
- 2 3 . 2
- 2 3 . 0
- 2 2 . 8
- 2 2 . 6
- 2 2 . 4
- 2 2 . 2
- 2 2 . 0
- 2 1 . 8
- 2 1 . 6
- 2 1 . 4
 
ln
σσ σσ
1 / T 1 0
- 3
K
- 1
[ C u [ { 1 ,  4 - ( 2 '  H P D A ) }
2
] 2 H
2
O
 
Figure 2. Temperature dependence of electrical conductivity 
(The electrical conductivity of Cu[{1,4-(2'HPDA)}]2 2H2O varies from 4.842x10
– 6
 mhos/cm 
to 0.9x10– 6 mhos/cm over the temperature range 454-498 K). 
2 . 0 2 . 1 2 . 2 2 . 3
- 1 9 . 4
- 1 9 . 2
- 1 9 . 0
- 1 8 . 8
- 1 8 . 6
- 1 8 . 4
 
 
ln
 σσ σσ
1 / T 1 0
- 3
K
- 1
[ C d { 1 P - 4 - ( 2 '  H P D A ) }
2
]
 
Figure 3. Temperature dependence of electrical conductivity 
 (The electrical conductivity of Cd[{1P-4-(2' HPDA)}] varies from 8.74x10-5 mhos/cm to 
5.12 x10– 5 mhos/cm over the temperature range 444 – 524 K). 
801 M. REVANASIDDAPPA et al. 
1 . 9 2 1 . 9 6 2 . 0 0 2 . 0 4 2 . 0 8
- 1 8 . 0
- 1 7 . 9
- 1 7 . 8
- 1 7 . 7
- 1 7 . 6
- 1 7 . 5
- 1 7 . 4
- 1 7 . 3
- 1 7 . 2
- 1 7 . 1
 
 
ln
 σ
1 / T 1 0
- 3
 K
- 1
[ C o  { 1 P - 4 - ( 2 '  H P D A ) }
2
 ] 2  H
2
O )
 
Figure 4. Temperature dependence of electrical conductivity 
 (The electrical conductivity of Co[{1P-4-(2' HPDA)}]2 2H2O varies from 4.55x10
–4  
 
mhos/cm to 1.4x10 – 4 mhos/cm over the temperature range 478 – 540 K). 
 From the Arrhenius plots clearly indicates the effect of complexation with different transition 
metals on the electrical conductivity of N- azines. The conductivity of metal free ligand is insulator. 
After complexation, the conductivity increases as increase in the temperature when compared to 
that of ligand. At room temperature they behave as an insulator but higher temperature shows semi 
conducting nature. This may be due to the overlap between the electrons in the anti bonding π-
orbitals of the σ donor ligand (N–azines), the empty d-orbitals of the different transition metal 
cation. It leads to delocalization of the π-electronic charges on the azine molecules. Based on 
spectral data and electrical measurement reveals that these complexes are monomeric in nature.   
Conclusion 
Activation energy of different azine metal complexes investigated in the range of 0.21- 
0.63eV.  Figure 1-4 demonstrate the variation of logarithmic conductivity values as a 
function of reciprocal temperature. At lower temperature 25–100°C they behave as insulator, 
where as they show semi conducting behaviour in the temperature range 100–250°C. The 
orders of the activation energy for the metal complexes are as follows: Cu > Co > Cd > Ni. 
Reference 
1. Sheats J E Pittman C U and Carraher C E, Chem Brit., 1984, 709. 
2. Carraher C E, J Chem Ed., 1981, 58, 921. 
3. Marcu M and Dimma M, Rev Roum Chim., 1970, 15, 1465.  
4. Shirai H, Macromol Chem., 1979, 180, 2074.  
5. Manecks G, Wille G W and Kossmeri Die G, Macromol Chem., 1972, 160, 111. 
6. Keller H J, Klutz T, Maensteelt H and G Renner, Springer Ser Solid State Sci., 
1987, 76, 448. 
7. Diaz F R, Tagle L H and Godoy, Bol Soc Chil Quim., 1986, 41(2), 49–52. 
8. Revanasiddappa M, Ph.D. Thesis, Gulbarga University, Gulbarga, India, 2005. 
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Electrical Conductivity Studies on Co(II), Cu(II), Ni(II) and Cd(II) Complexes of Azines

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Electrical Conductivity Studies on Co(II), Cu(II), Ni(II) and Cd(II) Complexes of Azines

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