ISSN 1070-4272, Russian Journal of Applied Chemistry, 2008, Vol. 81, No. 5, pp. 906!908. + Pleiades Publishing, Ltd., 2008.
Original Russian Text + O.T. Torebekov, T.K. Dzhumadilov, E.A. Bekturov, 2008, published in Zhurnal Prikladnoi Khimii, 2008, Vol. 81, No. 5,
Molecular Complexes of Polyethylene Glycol (MW 15000)
with Sodium Tetraphenylborate in Aprotic Solvents
O. T. Torebekov, T. K. Dzhumadilov, and E. A. Bekturov
Bekturov Institute for Chemical Research, Ministry of Education and Science of Kazakhstan Republic,
Received March 23, 2007
Abstract-The melting point and crystallinity of molecular complexes are studied in aprotic solvents in
relation to the solvent donor number.
It is well known that, in chemical reactions in
solutions, a solvent is not only a medium, but also
a reagent. The contribution of a solvent is complex.
Basic parameters characterizing properties of solv-
ents are the dielectric constant, dipole moment,
donor3acceptor power, etc. However, Fialkov et al.
 have pointed out that, in complexation, the key
factor is the specific character of solvation of ions
rather than the dielectric constant of a solvent.
Donor3acceptor properties of solvents character-
ize their chemical activity responsible for the solvent
effect on reactions in solutions. In this respect, it was
interesting to study the solvent effect on structure
and phase formation of complexes of polyethers
with low-molecular-weight salts and their properties.
Previously we examined the solvent effect on
these systems for several aprotic solvents using
optical microscopy and X-ray diffraction analysis.
In this work, we studied the structure and com-
position of complexes polyethylene glycol3sodium
tetraphenylborate in one more aprotic solvent, di-
methyl sulfoxide (DMSO), and discussed the results
obtained for a series of aprotic solvents.
Sodium tetraphenylborate NaB(C
ally pure grade) was dried prior to use. Polyethylene
glycol (PEG) (MW 15000) (Schuchardt, Germany)
was dried in a low vacuum. DMSO was purified
using the standard procedure .
The complexes were synthesized by mixing solu-
tions of individual components under ambient con-
ditions. The solvent was removed in a vacuum at
room temperature. Then, samples were vacuum-
dried to constant weight at 3033308 K for several
The melting points of the starting components
and their molecular complexes were determined on
a Boetius optical microscope (Rapido, Germany) at
a magnification of 16.
Large-angle X-ray diffraction patterns were ob-
tained on a DRON-3 instrument with CuK
tion (35 kV, 20 mA).
Based on the X-ray diffraction data, a structural
diagram for the system PEG3NaBPh
which consists of five sections (Fig. 1). Curves 1
and 2 show the correspond to NaBPh
PEG : NaBPh
Fig. 1. Structural diagram of the system PEG!NaBPh
in DMSO: (1) NaBPh
,(2) PEG, and (3!5) molecular