ISSN 0012-5016, Doklady Physical Chemistry, 2014, Vol. 455, Part 2, pp. 56–59. © Pleiades Publishing, Ltd., 2014.
Original Russian Text © I.V. Lunev, A.A. Khamzin, I.I. Popov, M.N. Ovchinnikov, I.S. Ryzhkina, O.M. Mishina, Yu.V. Kiseleva, A.I. Konovalov, 2014, published in Doklady Akademii
Nauk, 2014, Vol. 455, No. 6, pp. 656–660.
56
A previously unknown phenomenon consisting in
the formation of nanosized molecular ensembles,
referred to as nanoassociates, in aqueous solutions of
low concentrations (down to 10
–20
mol/L) have been
studied [1–6]. Concentration dependences of nanoas-
sociate size are nonmonotonic. This size changes from
a few tens to a few hundreds of nanometers. Although
the appearance of nanoassociates is initiated by a sol-
ute, they are mainly composed of ordered water struc-
tures. Prerequisites for the nanoassociate formation in
aqueous solutions are the action of external physical
fields (geomagnetic field and low-frequency electro-
magnetic fields) and a definite structure of a solute [2].
A correlation has been found between nanoassociate
parameters (the size and ζ-potential) and physico-
chemical properties of solutions (electric conductivity,
pH surface tension), as well as between nanoassociate
parameters and the bioeffects of solutions [3, 4, 10].
A combined study of low-concentration solutions
(10
–7
–10
–11
mol/L) of membranotropic amphiphilic
calix[4]resorcinarene with tris(hydroxymethyl)meth-
ylamide groups (1) by dynamic light scattering (DLS)
and atomic force microscopy (AFM) has demon-
strated that nanoassociates are capable to further self-
organize into structures the size (1–3 μm) and shape
of which changes as a function of concentration of 1.
The emergence of optical activity in solutions of sur-
face-inactive compound 1 in the range of low concen-
trations with a maximum at 1 × 10
–10
mol/L has been
revealed for the first time. It has been suggested that
the appearance of unique physicochemical properties,
in particular, optical activity, of low-concentration
solutions is due to formation, by nanoassociates, of
more complex spatial structures [5].
Thus, by now, experimental data on the correlation
between concentration-induced nanoassociate rear-
rangements and the appearance of unique physicochem-
ical properties of low-concentration solutions have been
accumulated and, for an understanding of these data, the
nature of nanoassociates should be known.
Among physicochemical methods used for study-
ing intermolecular interactions in liquids, an impor-
tant place is occupied by dielectric spectroscopy,
which provides information on the structure of solu-
tions [7].
In this context, the present work is aimed at study-
ing solutions of 1 by the dielectric spectroscopy
method, namely, at measuring the dielectric permittiv-
ity as a function of frequency, the alternating current
(ac) conductivity, and concentration dependences of
the direct current (dc) conductivity of low concentra-
tion solutions of 1 (1 × 10
–6
–1 × 10
–12
mol/L).
Solutions were prepared with the use of double dis-
tilled water; the quality of the latter was monitored by
measuring the conductivity, surface tension, and DLS.
1
O O
O O
NH HN
OH
HO
OH
OH
HO
O
O
O
O
N
N
OH
OH
OH
OH
O O
O O
HN NH
OH
HO
HO
OH
O
O
O
O
N
N HO
HO
OH
HO
OH
OH
OH
HO
OH
HO
HO
H H
H H
PHYSICAL
CHEMISTRY
Dielectric Spectroscopy Study of Low-Concentration Aqueous
Solutions of a Calix[4]resorcinarene Derivative
I. V. Lunev
a
, A. A. Khamzin
a
, I. I. Popov
a
, M. N. Ovchinnikov
a
, I. S. Ryzhkina
b
,
O. M. Mishina
b
, Yu. V. Kiseleva
b
, and Academician A. I. Konovalov
b
Received December 5, 2013
DOI: 10.1134/S0012501614060013
a
Kazan (Volga) Federal University,
ul. Kremlevskaya 18, Kazan, 420008 Tatarstan, Russia
e-mail: airat.khamzin@rambler.ru
b
Arbuzov Institute of Organic and Physical Chemistry,
Kazan Scientific Center, Russian Academy of Sciences,
ul. Akademika Arbuzova 8, Kazan, 420083 Tatarstan, Russia