Synthesis and properties of polymeric copper complexes with schiff bases

Article abstract of DOI:10.1007/s11167-005-0524-4

The electrochemical synthesis and properties of polymeric copper complexes with tetradentate (N₂O₂) Schiff bases were studied. The effects of the metal center and ligand surrounding of the starting compounds on the mechanism and kinetics of the charge transport in the polymers are discussed.

Full text of DOI:10.1007/s11167-005-0524-4

Russian Journal of Applied Chemistry, Vol. 78, No. 9, 2005, pp. 1391 1397. Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 9,
2005, pp. 1416 1422.
Original Russian Text Copyright
2005 by Rodyagina, Chepurnaya, Vasil’eva, Timonov.
INORGANIC SYNTHESIS
AND INDUSTRIAL INORGANIC CHEMISTRY
Synthesis and Properties of Polymeric Copper Complexes
with Schiff Bases
T. Yu. Rodyagina, I. A. Chepurnaya, S. V. Vasil’eva, and A. M. Timonov
Herzen Russian State Pedagogical University, St. Petersburg, Russia
Received April 7, 2005
Abstract The electrochemical synthesis and properties of polymeric copper complexes with tetradentate
(N2O2) Schiff bases were studied. The effects of the metal center and ligand surrounding of the starting
compounds on the mechanism and kinetics of the charge transport in the polymers are discussed.
Polymeric complexes of transition metals (M) with
tetradentate (N O ) Schiff bases {poly-[M(Schiff)]}
[Cu(SaltmEn)] and [Cu(CH O SaltmEn)], by the fol-
lowing procedure.
3
2
2
have a number of unique properties, such as directed
redox conductivity, electrochromism, and the capabil-
ity of selective catalysis of important chemical proc-
esses involving organic compounds [1 3]. This set
of properties of poly-[M(Schiff)] polymers makes
them promising for development of new optoelectron-
ic and sensory devices and energy-storing and catalyt-
ic systems.
The ligands H SaltmEn and H CH O SaltmEn
2
2
3
were prepared by mixing hot saturated alcoholic solu-
tions containing stoichiometric amounts of the corre-
sponding aldehydes and diamino derivatives: salicyl-
aldehyde (Aldrich) and 2,3-diamino-2,3-dimethyl-
butane (H SaltmEn) or o-vanillin (Aldrich, 97%) and
2
2,3-diamino-2,3-dimethylbutane (H CH O SaltmEn).
2
3
2,3-Diamino-2,3-dimethylbutane was obtained by the
reduction of 2,3-dimethyl-2,3-dinitrobutane (Aldrich)
with hydrogen [8]. The resulting ligands were filtered
under vacuum, washed with cold distilled water and
ethanol, and dried in air.
Nickel(II) and copper(II) compounds are the most
practically significant among poly-[M(Schiff)] poly-
mers owing to a relatively low cost. Papers devoted
to nickel-containing polymers are numerous, but
only a few studies [4 6] concerned poly-[Cu(SalEn)]
polymers
To prepare the complexes, a saturated acetonitrile
solution of appropriate ligand was added to a saturated
aqueous solution of Cu(CH COO) (Vekton, chemi-
R R
R R
3
2
cally pure grade); the solutions contained stoichiomet-
ric amounts of the reactants. Then the mixture of the
reactants was refluxed for 20 30 min; the precipitates
were washed with water and acetonitrile, filtered off,
and recrystallized from acetonitrile. The yield of
N
N
M
O
O
R
R
where M is Cu; R, R = H, [Cu(SalEn)]; R = OCH ,
R = H, [Cu(CH O SalEn)]; R = H, R = CH ,
[Cu(SaltmEn)]; R = OCH , R = CH [Cu(CH O
[Cu(CH O SaltmEn)] and [Cu(SaltmEn)] was 44 and
3
3
3
49%, respectively.
3
3
3
3
All the complexes were identified by X-ray diffrac-
tion analysis using a Bruker D-5000 diffractometer.
The composition and structure of the synthesized com-
SaltmEn)].
Here we made a first systematic study of the for-
mation and properties of [Cu(Schiff)] polymeric com-
plexes. These results make it possible to carry out
a purposeful synthesis of materials with preset proper-
ties for various applications.
plexes [Cu(SaltmEn)] (a) and [Cu(CH O SaltmEn)]
3
(b) are shown below.
To prepare supporting electrolyte solutions, we
used the following salts: tetraethylammonium tetra-
fluoroborate (Et N)BF , tetraethylammonium per-
4
4
EXPERIMENTAL
chlorate (Et N)ClO , and tetraethylammonium hexa-
4
4
fluorophosphate (Et N)PF (all purchased from
The complexes [Cu(CH O SalEn)] and [Cu(SalEn)]
were synthesized by the procedures from [5, 7], and
4
6
3
Merck, 97%). Before preparing the solutions, the salts
1070-4272/05/7809-1391 2005 Pleiades Publishing, Inc.

1392
RODYAGINA et al.
(a)
(b)
were dried at 125 C for 12 h in an inert atmosphere.
Solvents were acetonitrile (AN, Kriokhrome, 0 grade)
and dimethylformamide (DMF, Merck, 98%).
tials are given relative to this reference electrode.
An auxiliary electrode was a platinum grid (surface
area about 5 cm ). The voltammograms of the proc-
2
esses involving some of the complexes under study in
acetonitrile solutions are given as an example in
Fig. 1. The voltammograms were recorded by single
scanning of the potential from 0 to the anode region
up to 1.2 1.4 V and back. The anode part of the
voltammograms is the most informative for studying
electrolytic oxidation of the compounds under con-
sideration, as the reverse potential scanning is accom-
panied by reduction of the forming polymeric com-
plexes immobilized on the electrode surface, which is
described by the relationships characteristic of thin-
layer voltammetry. The voltammograms of all the
complexes under study are characterized by the pres-
ence of two anode maxima; the overall shape of the
anode branches of the voltammograms corresponds to
the EEC [9] mechanism of the electrolytic oxidation
To determine the number of electrons participating
in electrochemical processes, we used ferrocene
Fe(C H ) (Merck, 98%) as a reference.
5
5 2
We used a computerized complex based on an
Epsilon 2 (BAS) potentiostat for electrochemical ex-
periments, which were carried out in a hermetically
sealed three-electrode cell with separated electrode
compartments. A working electrode was a BAS MF
2012 glassy graphite disk 3 mm in diameter (surface
2
area 0.07 cm ). The surface of the working electrode
was polished prior to the experiments using diamond
powders with particle sizes of 3 and 1 m (BASi PK-4
polishing kit), washed with acetonitrile, and dried in
air. The reference electrode was AgCl/Ag filled with
a saturated NaCl solution (RE-5B BAS). All poten-
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 78 No. 9 2005

SYNTHESIS AND PROPERTIES OF POLYMERIC COPPER COMPLEXES
1393
I, A
I, A
(a)
(b)
E, V
E, V
Fig. 1. Voltammograms of redox processes involving (1) complexes and (2) ferrocene, recorded with a glassy graphite electrode
2
1
(S = 0.07 cm ) in an AN solution. Potential scanning rate V = 0.05 V s ; the same for Fig. 2. Concentration (M): complexes
s
3
and ferrocene 1 10 , (Et N)BF 0.1. (I) current strength and (E) potential; the same for Fig. 2. (a) [Cu(SaltmEn)] and
(b) [Cu(CH O SaltmEn)]; the same for Fig. 2.
4
4
3
(E is an electrochemical stage, and C, a chemical
reaction conjugated with it). Comparison of the oxida-
tion voltammograms of the copper complexes and fer-
rocene used as a reference shows that both electro-
chemical steps are one-electron. The potentials of the
anode maxima in the voltammograms of the com-
plexes and individual ligands in AN and DMF solu-
tions are given in Table 1.
when a polymer is formed, the two-electron oxidation
of the starting complex is accompanied by a chemical
reaction of the coordination of a [Cu(Schiff)] molecule
to the product of the electrolytic oxidation.
The potentials E for [Cu(SalEn)] and [Cu(Saltm-
pa1
En)] and E for [Cu(CH O SalEn)] and [Cu(CH O
pa2
3
3
SaltmEn)] in the voltammograms of the complexes in
acetonitrile solutions are close to each other (1.00
1.12 V), irrespective of the presence of electron-donor
methoxy groups in the phenyl moiety. A similar fact
is observed also in the voltammograms recorded in
DMF (1.05 1.08 V).
An electrochemical study of the oxidation of
[Cu(Schiff)] complexes revealed the following facts.
The formation of polymeric compounds on the
electrode surface was observed only when the com-
plexes were oxidized in a solvent with a low coordina-
ting power (AN). As shown previously [10, 11] for
the related nickel and palladium complexes, passing
from AN to DMF having a higher donor number [10]
favors stabilization of the electrochemical oxidation
products in the form of inert octahedral complexes
containing axially coordinated solvent molecules.
Table 1. Potentials of anode maxima Epa1 and Epa2 of
voltammograms of the complexes [Cu(Schiff)] and ligands
1
H2(Schiff). Vs = 0.05 V s
AN
DMF
Complex, ligand
Epa1
Epa2
Epa1
Epa2
Using the reference compound, we found that the
electrolytic oxidation of all the complexes under study
is a two-electron process in both acetonitrile and DMF.
When the complexes [Cu(SalEn)] and [Cu(SaltmEn)]
are oxidized in DMF solutions, the potentials of the
maxima of both oxidation waves are close to each
other, and, as a result, only one anodic current maxi-
mum is observed in the voltammograms. At the same
time, it was found by in situ microgravimetry [12]
that the electrochemical oxidation of the copper com-
plexes under consideration in acetonitrile solutions
involves one electron per fragment of a [Cu(Schiff)]
polymer. The whole set of these facts indicates that,
V
[Cu(SalEn)]
H2(SalEn)
[Cu(CH3)O SalEn)]
H2(CH3O SalEn)
[Cu(SaltmEn)]
H2(SaltmEn)
1.00
1.22
1.24
1.10
0.96
1.27
1.44
1.12
1.09
1.08
1.34
0.99
1.01
1.05
1.31
0.99
0.99
1.10*
0.83
0.86
1.01
1.13
1.07
[Cu(CH3O SaltmEn)] 0.86
H2(CH3O SaltmEn)
1.07
1.05
0.83
* Shoulder.
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 78 No. 9 2005

1394
RODYAGINA et al.
and [Cu(SaltmEn)] are close to each other. The same
is also true for [Cu(CH O SalEn)] and [Cu(CH O
SaltmEn)].
I, A
(a)
3
3
The limiting step of the polymerization of the
complexes under study is the diffusion of the starting
compounds to the electrode surface, which is con-
firmed by the fact that the currents of the anode
maxima in the voltammograms increase linearly as the
concentration of the starting substances in solution in-
4
3
creases (in the range 1 10 3 10 M).
On the whole, the experimental data for the com-
plexes [Cu(Schiff)] agree with the general mechanism
of the electrochemical oxidation of complexes
[M(Schiff)] suggested previously [10, 11].
E, V
I, A
(b)
The formation of the polymeric complexes poly-
[Cu(SaltmEn)] and poly-[Cu(CH O SaltmEn)] on the
3
surface of a glassy graphite electrode in the case of
potential cycling is shown in Fig. 2. The voltammo-
grams of the polymers recorded after the polymeriza-
tion was complete and the modified electrode was
transferred into the supporting electrolyte are also
shown in Fig. 2 for comparison.
The regular increase in the currents of the anode
and cathode maxima in the voltammograms corre-
spond to the growth of polymeric compounds on the
electrode. In the course of the formation of polymers,
starting from the second cycle, a new broad anodic
wave of the oxidation of polymers on the electrode
surface is observed in the voltammograms at poten-
E, V
Fig. 2. Voltammograms of redox processes involving
complexes, recorded with a glassy graphite electrode (S =
0.07 cm ) in acetonitrile solutions. Concentration (M):
2
3
complexes 1 10 , (Et N)BF 0.1. (a) [Cu(SaltmEn)] and
4
4
(b) [Cu(CH O SaltmEn)]. Numbers at curves correspond to
3
successive cycles. Dashed lines: voltammograms of poly-
mers recorded after polymerization termination (20 cycles)
and transfer of the modified electrode into a supporting
tials more negative than E . At the same time, the
pa1
anode wave corresponding to the transfer of the sec-
ond electron, after which the formation of the polymer
was observed according to [13], is absent from the
voltammograms recorded in the supporting electrolyte
solution with electrodes modified with the polymers
(Fig. 2, dashed curves). The common trend for all
the polymers studied is a shift of the region of redox
processes to the side of less positive potentials when
donor methoxy groups are introduced into the ligand.
The introduction of methyl groups into the diamine
bridges between phenyl moieties does not noticeably
affect the shape and position of the voltammograms of
the polymers. Thus, the voltammograms of the poly-
meric complexes poly-[Cu(SalEn)] and [Cu(SaltmEn)]
only slightly differ from each other in the specified
parameters.
1
electrolyte [0.1 M (Et N)BF , AN, V = 0.05 V s ].
4
4
s
Presumably, these oxidation waves correspond
to the electron transfer from predominantly metal-
centered orbitals of the complexes. Apparently, the
second oxidation waves of the complexes [Cu(SalEn)]
and [Cu(SaltmEn)] and the first oxidation waves of
[Cu(CH O SalEn)] and [Cu(CH O SaltmEn)] are
determined by the electron transfer from predominant-
ly metal-centered orbitals. This is proved by the fact
that the maxima of potentials of these waves are con-
siderably shifted toward the negative region when
electron-donor methoxy groups are introduced into
the phenyl moieties.
3
3
The introduction of four methyl groups into the di-
amine bridge connecting the phenyl moieties does not
result in a noticeable change in the electron density on
the ligands, as methyl groups are weak donors. There-
fore, the potentials of the current maxima in the oxi-
dation voltammograms of the complexes [Cu(SalEn)]
Two pairs of anode and cathode waves are ob-
served in the voltammograms of all the polymeric
complexes studied. At the same time, it was found
previously for nickel [14] and copper [12] polymeric
complexes that the reduction oxidation of polymers
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 78 No. 9 2005

SYNTHESIS AND PROPERTIES OF POLYMERIC COPPER COMPLEXES
1395
in the range of potentials 0 1.3 V is characterized by
the transfer of one electron per fragment. At present,
the nature of processes giving rise to two pairs of
waves in the voltammograms of the polymeric com-
plexes under discussion is not determined unambigu-
ously. A possible reason for the observed shape of
the voltammograms can be the presence of two poly-
meric forms on the electrode surface, which are bound
to the surface owing to the interaction between pre-
dominantly metal- or ligand-centered orbitals of the
surface fragments of stacks and are correspondingly
oxidized (or reduced) at different potentials. The other
probable reason for the appearance of the broadened
oxidation waves corresponding to the redox processes
in the polymers can be the presence of polymeric
stacks of different length on the surface, having dif-
ferent resistance to charge transfer.
transfer rates in various polymers. Nevertheless, the
resulting D values can be used for comparison of
ct
charge transfer rates in the same polymer formed
under different conditions.
The resulting D values for all the complexes
ct
under study are close to each other and fall into the
10
2
1
range (1 0.5) 10
cm s for the range of the
formation potential 1.00 1.10 V. This range of the
polymer formation potentials is more positive than
the potential of the first anodic maximum in the oxi-
dation voltammograms of the starting complexes and,
at the same time, overlaps with the range of potentials
of the second oxidation process (Table 1). The forma-
tion of polymers at potentials lower than 0.95 V ap-
parently results in the fact that the primary product of
the electrolytic oxidation of the starting compound is
partially stabilized owing to side processes involving
a solvent, instead of the transfer of the second conduc-
tion electron. Monomeric and oligomeric fragments
forming by the side processes can be captured by the
growing polymeric film, which disturbs its structure
and results in a decrease in the efficiency of the
motion of charge carriers (in this case, the resulting
Polymeric complexes can be formed also in a static
mode when an electrode is polarized in a solution of
the starting compound at a constant potential. In this
case, the most important parameter is the polymer
formation potential providing, on the one hand, a suf-
ficient rate of the electrochemical process and, on
the other hand, the absence of side reactions resulting
in the degradation of the polymer or in the loss of its
electrochemical activity. The criterion for choosing
the optimal potential of the formation of polymers can
11
2
1
D
values are close to 10
cm s ).
ct
The formation of polymers at potentials higher than
1.2 V is accompanied by the irreversible oxidation of
the ligand surrounding of the complexes and results
in the loss of the polymer electrochemical activity.
be the charge diffusion coefficient D reflecting the
ct
redox conductivity of the polymeric compounds.
The nature of the limiting step of charge transfer
processes in the films of the polymers under study
was determined by studying the effect of the size of
charge-compensating ions (BF , ClO , and PF ) [17]
To choose an optimal formation potential, we have
prepared polymer films at various potentials in the
range 0.9 1.2 V. The coefficients of charge diffusion
in polymers were calculated by the Randles Sevcik
equation [15] on the basis of voltammograms recorded
at potential scanning rates that provided the occur-
rence of redox processes in the polymer in the mode
corresponding to the conditions of semiinfinite diffu-
sion of current carriers. The calculation of the charge
diffusion coefficients implies the exact knowledge of
concentration of redox centers in the polymer, i.e., of
the density of the polymeric film [16]. The density of
the polymeric films based on the complexes with the
4
4
6
and concentration of supporting electrolytes (0.05
0.5 M) on D . The experiments showed that the
ct
charge transfer rate in all the polymers studied is
independent of the size of charge-compensating anions
and of their concentration in solution. The results
obtained show that the charge transfer in these films is
limited not by the stage of diffusion of counterions in
them, but by the rate of electron motion along poly-
meric stacks; therefore, the resulting D values char-
ct
acterize the rate of specifically this process.
3
To compare characteristics of the charge transport
in the polymeric complexes with various ligands and
metallic centers, we can use the products of the con-
ligand SalEn, about 1 g cm , was determined previ-
ously by in situ ellipsometry [13]. Certainly, the
density of the polymers depends on the presence of
various substituents in the ligand surrounding, altering
the geometry of the starting monomeric fragments.
The exact values of the density of the polymers con-
3
centrations of redox centers in a polymer c (mol cm )
1/2
by D values dependent on changes in the structure
ct
of polymers with variation of their composition and
on the efficiency of the motion of charge carriers.
taining SaltmEn and CH O SaltmEn ligands are
3
1/2
The cD
values for the poly-[Cu(Schiff)] polymers
unknown; therefore, the density of the polymers in
ct
3
calculated by the Randles Sevcik equation are given
in Table 2; the related characteristics of nickel- and
these calculations was taken equal to 1 g cm . This
assumption does not allow us to compare the charge
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 78 No. 9 2005

1396
RODYAGINA et al.
for poly-[Cu(Schiff)] polymers
1/2
Table 2. Values of cD
ct
1/2
1/2
1/2
1/2
Complex
cD
108, mol cm 2 s
Complex
cD
108, mol cm 2 s
ct
ct
poly-[Ni(SalEn)]
poly-[Pd(SalEn)]
poly-[Cu(SalEn)]
poly-[Ni(CH3O SalEn)]
poly-[Pd(CH3O SalEn)]
poly-[Cu(CH3O SalEn)]
4.0 0.5
2.5 0.5
1.5 0.5
5.0 0.5
3.0 0.5
1.5 0.5
poly-[Ni(SaltmEn)]
poly-[Pd(SaltmEn)]
poly-[Cu(SaltmEn)]
poly-[Ni(CH3O SaltmEn)]
poly-[Pd(CH3O SaltmEn)]
poly-[Cu(CH3O SaltmEn)]
12.0 0.5
5.6 0.5
2.0 0.5
5.5 0.5
4.6 0.5
2.0 0.5
palladiuim-containing polymeric complexes obtained
previously [18] are given for comparison.
23]. The difference in the nature of bonds between
fragments of stacks in the copper polymeric com-
plexes compared to nickel- and palladium-containing
polymers offers an explanation for the data obtained
in this study, in particular, for a lower electronic con-
ductivity of poly-[Cu(Schiff)] complexes.
Our results allow the following conclusions:
1/2
(i) cD parameters for the copper complexes studied
ct
are lower than those for the polymeric nickel and pal-
ladium complexes; (ii) poly-[Cu(Schiff)] polymers are
characterized by slow electron transport in stacks in
contrast to nickel- and palladium-containing polymers,
in which the limiting step of the charge transport is
the motion of charge-compensating ions [18]; (iii) the
effect of substituents in ligand surroundings on the
behavior of compounds in polymeric complexes poly-
[Cu(Schiff)] essentially differs from that in the nickel-
and palladium-containing polymers owing to a change
in the nature of the limiting step of the charge trans-
CONCLUSIONS
(1) Previously unknown polymeric copper com-
plexes with the ligands N,N -2,3-dimethylbutane-
2,3-diylbis(salicylidenimine) and N,N -2,3-dimethyl-
butane-2,3-diylbis(3-methoxysalicylidenimine) were
prepared. The conditions for the electrochemical syn-
thesis of the polymers with the highest redox conduc-
tivity [optimal potentials of the formation of cop-
per(II) polymeric complexes with Schiff bases, nature
and concentration of the supporting electrolyte] were
determined.
port. In particular, for poly-[Ni,Þd(Schiff)] complexes,
1/2
cD
substantially increases on passing from the
ct
polymers with the SalEn ligand to those with the
SaltmEn ligand. As shown in [19], the introduction of
four methyl groups into the structure of the diamine
bridge between the phenyl moieties results in a notice-
able increase in the repulsive interactions between the
polymer stacks and in the formation of a less compact
polymeric film. For [Cu(Schiff)] polymers, such a
change in the ligand surrounding results in increasing
efficiency of the motion of charge-compensating ions,
but does not noticeably affect the charge-transfer rate.
(2) The oxidation of the poly-[Cu(Schiff)] com-
plexes occurs by the two-electron mechanism with the
subsequent chemical step of the coordination of a
starting complex molecule to the product of the elec-
trochemical oxidation; the limiting step of the poly-
merization is the diffusion of the starting compounds
to the electrode surface.
(3) A study of the mechanism and kinetics of
charge transport showed that the electron transfer in a
stack occurs through an oxygen atom. Therefore, these
polymeric compounds are characterized by a slow
It is known that [Cu(Schiff)] complexes, unlike the
related nickel and palladium compounds, form inter-
molecular associates in the solid phase, in which
copper atoms are bound to each other through the
oxygen atom of a Schiff base. In the associates, the
length of the bond between the copper atom of one
molecule and the oxygen atom of another molecule is
electron transport along stacks, and the parameter
1/2
cD
for the copper(II) complexes studied is lower
ct
than for the related nickel and palladium polymeric
complexes.
2.41
[20]. Presumably, in [Cu(Schiff)] the bonds
between separate fragments in a stack are similar in
nature [21]. At the same time, it was found that in
the nickel and palladium polymeric complexes with
Schiff bases, the bonds between separate fragments
of stacks are formed by interaction of the metallic
centers with the phenyl moieties of the ligands [22,
(4) Variation of the ligand surrounding does not
affect the charge-transfer rate.
(5) The trends revealed in this study allow pur-
poseful synthesis of electroactive polymeric materials
with a preset range of potentials of the electrochemi-
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 78 No. 9 2005

SYNTHESIS AND PROPERTIES OF POLYMERIC COPPER COMPLEXES
1397
cal activity and with the required rate of charge trans-
port.
Elektrokhimiya, 1998, vol. 34, no. 10, pp. 1090 1096.
11. Vasil’eva, S.V., Balashev, K.P., and Timonov, A.M.,
Elektrokhimiya, 2000, vol. 36, no. 1, pp. 85 89.
ACKNOWLEDGMENTS
12. Rodyagina, T.J., Chepurnaya, I.A., Vasil’eva, S.V.,
and Timonov, A.M., in Trudy XXII Mezhdunarodnoi
Chugaevskoi konferentsii po koordinatsionnoi khimii
(Proc. XXII Int. Chugaev Conf. on Coordination
Chemistry), Chisinau, 2005, p. 217.
This study was financially supported by the Rus-
sian Foundation for Basic Research (project no. 04-
03-32979).
13. Hamnett, A., Abel, J., Eameaim, J., et al., J. Phys.
Chem. Chem. Phys., 1999, vol. 1, pp. 5147 5156.
The authors are grateful to Dr. Dale Svensson
(University of Iowa, the United States) for the assist-
ance in X-ray diffraction analysis of the compounds.
14. Vilas-Boas, M., Freire, C., De Castro, B., and Hill-
man, R., J. Phys. Chem. B., 1998, vol. 102, no. 43,
pp. 8533 8540.
REFERENCES
15. Galus, Zb., Teoretyczue podstawy elektroanalisy
chemicznej, Warsaw: Naukowe, 1971.
1. Popeko, I.E., Timonov, A.M., and Shagisultano-
va, G.A., Zh. Prikl. Khim., 1990, vol. 63, no. 10,
pp. 2207 2210.
16. Khannanov, N.K., Yatsun, T.F., Shafirovich, V.Ya.,
and Strelets, V.V., Izv. Akad. Nauk SSSR, Ser. Khim.,
1983, no. 6, pp. 1282 1290.
2. Dahm, C.E. and Peters, D.G., Anal. Chem., 1994,
17. Hurrell, H.C. and Abruna, H.D., Inorg. Chem., 1990,
vol. 66, p. 3117.
vol. 29, pp. 736 739.
3. Dahm, C.E. and Peters, D.G., J. Electroanal. Chem.,
18. Gaman’kov, P.V., Synthesis and Study of the Proper-
ties of Polymeric Ni and Pd Complexes with Schiff
Bases, Cand. Sci. (Chem.) Dissertation, St. Petersburg,
2004.
19. Dmitrieva, E.A., Logvinov, S.A., Kurdakova, V.V.,
et al., Elektrokhimiya, 2005, vol. 41, no. 4, pp. 433
441.
1996, vol. 406, p. 119.
4. Hoferkamp, L.A. and Goldsby, K.A., Chem. Mater.,
1989, vol. 1, no. 3, pp. 348 352.
5. Audebert, P., Capdevielle, P., and Maumy, M., New J.
Chem., 1992, vol. 16, no. 6, pp. 697 703.
6. Orlova, I.A., Popeko, I.E., Timonov, A.M., et al.,
Zh. Prikl. Khim., 1993, vol. 66, no. 3, pp. 584 589.
20. Hobday, M.D. and Smith, T.D., Coord. Chem. Rev.,
7. Pfeiffer, P., Breith, E., Lubbe, E., and Tsumaki, T.,
Justus Leibigs Ann. Chem., 1933, vol. 503, pp. 84
130.
1972, vol. 3, pp. 311 316.
21. Shagisultanova, G.A. and Kuznetsova, N.N., Koord.
Khim., 2003, vol. 29, no. 10, pp. 760 765.
22. Popeko, I.E., Vasil’ev, V.V., Timonov, A.M., and
Shagisultanova, G.A., Zh. Neorg. Khim., 1990, vol. 35,
no. 4, pp. 933 937.
8. Sayre, R., J. Am. Chem. Soc., 1955, vol. 77, pp. 6689
6692.
9. Polcyn, D.S. and Shain, I., Anal. Chem., 1966, vol. 38,
pp. 370 385.
23. Dahm, C.E., Peters, D.G., and Simonet, J., J. Electro-
anal. Chem., 1996, vol. 410, pp. 163 171.
10. Vasil’eva, S.V., Balashev, K.P., and Timonov, A.M.,
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 78 No. 9 2005