Russian Journal of Applied Chemistry, 2011, Vol. 84, No. 9, pp. 1626−1628.
Pleiades Publishing, Ltd., 2011.
Original Russian Text © N.P. Rusakova, V.V. Turovtsev, Yu.D. Orlov, 2011, published in Zhurnal Prikladnoi Khimii, 2011, Vol. 84, No. 9, pp. 1578−1580.
Comparison of Electronegativities of Groups of Certain
Organic and Inorganic Molecules
N. P. Rusakova, V. V. Turovtsev, and Yu. D. Orlov
Tver State University, Tver, Russia
Received May 25, 2010
Abstract—For functional groups containing oxygen and sulfur atoms qualitative relationships were obtained and
a row of electronegativities was set up within the limits of the “quantum theory of atoms in molecules.” Possibilities
of forecasting composition-property correlations on a speciﬁ ed basis were discussed.
Physicochemical, biological, and many other proper-
ties of compounds can be forecasted on the basis of their
geometrical structures and distribution of electronic
density [1, 2]. This proposition forms the basis for quan-
titative structure-activity (QSAR) and structure-property
(QSPR) relationships. The main factor, which affects
correctness of chemical models, is the uncertainty in the
transferability of functional groups forming a molecule
(a methodical error). It results in increasing errors in the
calculation of derived characteristics. Therefore the ways
of improvement of QSAR and QSPR forecasting power
should include procedures of minimization of methodical
errors based on the analysis of intramolecular interactions.
An important tool of the qualitative and quantitative
description of intramolecular interactions is the inductive
effect (I-effect)  and the concept of electronegativity
χ connected to it [4–9]. Electronegativity is the property
of atoms or groups in a molecule to donate (+I) or to
accept (–I) electronic density of substituents. From the
viewpoint of classical chemistry, arising redistribution
of electronic density of groups results in the appearance
and localization of nucleophilic and electrophilic ﬁ elds
within the limits of a single molecule. Therefore concepts
and space assignment of nucleophility and electrophility
should naturally follow from the comparison of electro-
negativities of groups. The charge of an atom or a group
arising under the action of neighboring structural parts can
serve as the quantitative measure of χ, and the variation
of charges upon the replacement of atomic groups allows
comparing values of χ of replaced groups. Knowledge
of the distribution of partial (group) charges allows us
to surmise a possible reactive center of a molecule, its
orientation relative to a reagent and thus to carry out «the
molecular design» of organic compounds of various types
 deﬁ ned by electronic effects of substituents.
It was shown earlier that the inductive effect of a wide
range of atomic groups rapidly damps out and extends
no more than through three chemical bonds . There-
fore a predicted extensive property of a molecule can
be presented in the form of the sum of contributions of
partial properties of groups [11–13] with corresponding
corrections for the inductive effect . The transferability
of group properties is equivalent to the transferability of
electronic density related to these groups and should be re-
ﬂ ected on the transferability of their charges, which in turn
can be estimated from comparison of electronegativities.
Earlier a qualitative and quantitative comparison of
electronegativities for a great number of substituents
has been carried out on the basis of comparison of their
natural (according to the nomenclature of ) charges.
Differences of electronegativities of a number of groups
R and R' [i.e. Δχ = χ(R) – χ(R')] found by numerical dif-
ferentiation of total energy with respect to a number of
electrons are given in . Comparison of χ values for
hydrocarbons and their radicals was fulﬁ lled within the
limits of the “quantum theory of atoms in molecules”
(QTАIМ) [16–18]. However certain important atomic
groups containing sulfur and oxygen have not been con-
sidered in this case.
The aim of the present work was to create a qualita-