1070-4272/01/7402-0316 $25.00 C 2001 MAIK [Nauka/Interperiodica]
Russian Journal of Applied Chemistry, Vol. 74, No. 2, 2001, pp. 316!324. Translated from Zhurnal Prikladnoi Khimii, Vol. 74, No. 2, 2001,
Original Russian Text Copyright + 2001 by Ardasheva, Shagisultanova.
AND POLYMERIC MATERIALS
Redox Activity of Poly-[PdSalpn-1,2] as Influenced
by Thickness of Its Film and Composition
of Supporting Electrolyte
L. P. Ardasheva and G. A. Shagisultanova
Herzen State Pedagogical University, St. Petersburg, Russia
Received February 29, 2000
Abstract-The electron transfer rate in the bulk of a [PdSalpn-1,2] polymeric film was studied as influenced
by its thickness and the composition of the supporting electrolyte.
Procedures for preparing metal-containing polymeric
films have been under development recently. Previ-
ously, brightly colored electrochromic heteronuclear
and heteroligand Pd(II) complexes with bis(salicyl-
idene)-1,2-propylenediamine ([PdSalpn-1,2]), bis(sa-
licylidene)-1,3-propylenediamine ([PdSalpn-1,3]), and
have been prepared by electrochemical oxidative poly-
merization  and their physicochemical properties
(among which the most important are the electrical
conductivity and photosensitivity) have been studied.
It should be noted that the properties of these poly-
mers can be studied both in solutions of supporting
electrolyte and in the solid state. Further study of
the systems in question will give semiconductor char-
acteristics of substances belongind to this class.
In this work the rate of electro-stimulated charge
transfer in the polymers immersed in a solution of
supporting electrolyte was studied as influenced by its
composition and properties. In this case we deal with
a system of three interrelated components: electrode,
polymeric complexes immobilized on the electrode,
and supporting electrolyte. A change in the properties
of each component affects the properties of the whole
It is known that redox transformations of polymeric
systems prepared by oxidative polymerization are ac-
companied by migration of anions of the supporting
electrolyte inside and outside the polymeric matrix to
maintain its electroneutrality. Such an overall process
and the ions providing electroneutrality of the poly-
mer are commonly termed  doping and dopants, re-
Levi et al.  found that the molecular structure
of electron-conducting organic polymers is labile and
may undergo conformational transformations caused
by doping, swelling, and mechanical or electrochem-
ical interactions of counterions and electrical charges
of the polymeric chains. These transformations change
the redox activity of the polymers.
The influence of various factors on the redox activ-
ity of organic polymers has been extensively studied
. However, polymeric metal complexes have not
been investigated in this regard.
In this work, we studied the rate of electron diffu-
sion in the bulk of the polymer as influenced by exter-
nal factors (nature of the counterion and solvent and
the concentration of the supporting electrolyte) and
the thickness of the polymeric layer, one of the most
important parameters of the polymer.
Poly-[PdSalpn-1,2] was prepared by the procedure
described in . The polymer was identified by
electronic absorption spectroscopy and X-ray photo-
electron spectroscopy [16, 17]. The electrochemical
experiments were performed in a three-electrode cell
with separated compartments of the working, auxilia-
ry, and reference electrodes.
A 0.1 M solution of tetrabutylammonium perchlo-
) in acetonitrile, deaerated with high-
purity argon, was used as the supporting electrolyte.
Acetonitrile (AN) was purified by the procedure de-
scribed in . To study the dependence of the re-
dox conductivity of the polymer on the counterion