Russian Journal of Applied Chemistry, 2010, Vol. 83, No. 2, pp. 332−336.
Pleiades Publishing, Ltd., 2010.
Original Russian Text
A.A. Ostroushko, M.O. Tonkushina, A.P. Safronov, V.A. Vazhenin, M.Yu. Artemov, 2010, published in Zhurnal Prikladnoi Khimii,
2010, Vol. 83, No. 2, pp. 334−338.
AND POLYMERIC MATERIALS
Mutual Stabilization of Components in Composites
of Polyoxomolybdates of Buckyball Structure
and Water-Soluble Nonionic Polymers
A. A. Ostroushko, M. O. Tonkushina, A. P. Safronov, V. A. Vazhenin, and M. Yu. Artemov
Research Institute of Physics and Applied Mathematics, Gorky Ural State University, Yekaterinburg, Russia
Received July 9, 2009
Abstract—Thermal degradation of composites consisting of polyoxomolybdates of the buckyball structure (with
acetate and chloroacetate ligands) and water-soluble nonionic polymers was studied. The mutual stabilizing
effect of components of the systems with polyvinyl alcohol and polyvinylpyrrolidone under UV irradiation was
subjected to comparative analysis. The methods of differential scanning calorimetry, mass spectrometry, and
ESR spectroscopy were used.
Nanocluster polyoxomolybdates of buckyball struc-
ture form a novel class of compounds discovered about
10 years ago. By now, representatives of rather diverse
compositions have been prepared. Typical representatives
of buckyballs in which the only metallic component is
molybdenum are water-soluble Mo132 [(NH
 and Mo132 Cl[(NH
O · 15ClCH
Molybdenum compounds whose nanoclusters have
other shapes are also known : tore-shaped structures,
“nanohedgehogs,” etc. Molybdenum can also be replaced
by ions of other metals, e.g., Fe, V [4, 5], that leads to
changes in the chemical properties of the compounds.
Researchers’ attention is attracted by fairly large size
of charged nanocluster particles of polyoxomolybdates,
which are polyanions with internal cavities and windows
through which an exchange of water molecules with
other molecules and ions from the medium is possible [6,
7]. Thus, interaction of buckyballs with other substances
is possible in both outer and inner spheres.
An interesting feature is the possibility of controlled
modiﬁ cation of polyoxomolybdates by varying the nature
of their surfaces. In particular, these species can be made
soluble in organic media, which will allow their use, e.g., for
preparing thin layers suitable for making sensor coatings.
Polyoxometalates are capable of complexation with such
compounds as dimethyldioctadecylammonium salts ,
polyvinyl alcohol (PVAl), and polyvinylpyrrolidone
(PVP) . This fact allows buckyballs to be considered
as potential means for targeted delivery of substances in
a living body . Catalytic and sorption properties of
buckyballs are also of interest [10, 11].
A useful property of composites based on polyvinyl
alcohol and Mo132 is the capability of buckyballs
to stabilize the polymer [9, 12, 13] by blocking the
formation of radical species in the course of thermal
and photochemical aging. Mutual thermal stabilization
of the components of polymer–salt systems was
discovered previously for simpler polyoxometalates
[14, 15] such as ammonium heptamolybdate. In this
connection, it is interesting to perform a comparative
study of processes occurring on heating and irradiation
in composites consisting, along with buckyballs, also of
polymers of different nature such as polyvinyl alcohol
and polyvinylpyrrolidone. Certain basic data required
for such analysis are available, e.g., data on thermal
decomposition of individual polyoxometalates of
the buckyball structure in the crystalline state . It
should be noted that the previously used methods for
studying these processes give adequate information.
Such methods include differential scanning calorimetry