'Inductive' electronegativity scale: 2. 'Inductive' analog of chemical hardness

On the basis of a previously suggested approach to the calculation of 'inductive' electronegativities of atoms and groups a simple method of theoretical estimation of in situ inductive electronegativities is elaborated. The method also allows the determination of inductive local and global chemical hardness parameters on the basis of geometric characteristics of bonded atoms. This made it possible to provide a new 'steric' interpretation for some known chemical rules, such as the principle of maximum hardness. (C) 2000 Elsevier Science B.V

Inductive effect of substituents in the correlation analysis. The problem of quantitative estimation

Systematisation and analysis of the literature data concerning quantitative estimation of inductive interaction of functional groups in organic and organoelement compounds have been carried out. The data of own autor's works devoted to elaboration of new model of inductive effect which permits to calculate theoretically the inductive constants of various substituents at any reactive centers are generalised. The possibility of using the elaborated approach to solve some important theoretical questions connected with the problem of inductive effect, such as inductive influence in organoelement compounds and inductive effect of alkyl groups, is also discussed

Modelling of substituents electronic and steric effects for effective analysis of organoelement and organophosphorus reactivity

For the effective analysis of organic and organoelement reactivity and the reaction mechanisms we have elaborated a simple enough models of steric and inductive substituents effects, which allow to calculate theorically the steric and inductive constants of any substituent at any reactive center. Both of these models possess of clear and comprehensible physical meaning, their correctness was confirmed by a good agreement of theorically calculated constants with well-known experimental steric and inductive scales. The wide possibilities of the suggested models for investigation of reaction mechanisms, organic and organoelement (organophosphorus, in particular) reactivity are discussed on the basis of different important organophosphorus reactions Pudovik, Abramov, Willyamson, Kabachnic-Fields reactions, acidic-basis equilibria, addition and complexation processes, etc.)

'Inductive' electronegativity scale

A new approach to the calculation of group electronegativity is introduced on the basis of previously elaborated additive models for steric and inductive effects. The newly derived 'inductive' group- electronegativities χ1 correlate well with other well-established electronegativity X scales. A firm interrelation between three fundamental substituent characteristics: inductive and steric constants and group electronegativity is suggested

A new approach to the theoretical estimation of inductive constants

A new model of the inductive effect is proposed, allowing highly accurate theoretical calculations of inductive constants for a diversity of substituents, using a simple and readily available system of mathematics. According to this approach, the inductive effect of a substituent is considered in terms of the additive influence of its constituent atoms. A constant inherent capacity for inductive interaction with a reactive center (with a four-coordinate carbon atom chosen for such a center), represented by an atomic constant σA, is ascribed to each atom. Values of σA for a wide variety of atoms are determined, and their physical meaning is revealed to elucidate to a certain extent the physical nature of the inductive effect. In addition, the proposed model permits the convenient use in calculations of group constants σGcharacterizing the inductive power of groups. Values of σGare determined for molecular fragments that are most widely dealt with in organic chemistry, and the use of σAorσG constants and of their superposition is shown to have, in most cases, little or no effect on the accuracy and reproducibility of the results obtained. It is also shown that, in terms of the developed approach, the inductive effect of a substituent is closely associated with its conformation. Theoretical inductive constants were calculated for 427 organic, aromatic, organometallic and charged substituents, and they showed perfect correlation with the corresponding experimental values. © 1998 John Wiley & Sons, Ltd

A new approach to theoretical calculation of group electronegativities and its application for organoelement reactivity

The relationship between the structure and reactivity of compounds is one of the basic problems of organic and organoelement chemistry. On the basis of previously suggested models of steric and inductive substituents effects [1,2] a new theoretical approach has been elaborated which allows to calculate theoretically a numerous atomic and group descriptors called "inductive" reactivity indexes which can be used for the quantitative interpretation of reactivity and physical-chemical properties of various organic and organoelement - organophosphorus in particular - derivatives

Application of a model of inductive effect for analysis of the reactivity of organoelement compounds

Abundant published evidence is presented to show the practical utility of the previously developed model of inductive effect for analysis of the reactivity of organic and organoelement compounds. The universal character and high precision of the approach is demonstrated for 149 reaction series in terms of one- and two-parameter correlations, using calculated inductive and steric constants

Principle of electronegativity. State-of-the art

Modern views on atomic and group electronegativity are classified. Trends in the electronegativity concept development are analysed. Special attention is paid to the latest approaches to the electronegativity determination such as concept of an «orbital» electronegativity and density functional theory A method for determination of «inductive» electronegativities is suggested. This provides tor correct theoretical calculation of a substituent electronegativities based on electronegativities of individual atoms and a substituent spatial structure. It is shown that the approach developed posses a number of important advantages, e.g. allows for the calculation of group electronegativity of isomeric substituents avoiding utilisation of an electronegativity equalisation principle. A utilisation of literature data summary and the method proposed by us allows to formulate a view on electronegativity as invariable fundamental immanent characteristic of a chemical element

"Inductive" Electronegativities of Substituents at Various Reaction Centers

A new method, based on the previously developed model of the inductive effect and on fundamental physical and geometric parameters of atoms and groups, is proposed for calculating the atomic and group electronegativities. This approach allowed refinement of a number of very important theoretical concepts, such as the nature of the group electronegativity and its correlation with the main quantitative characteristics of the substituent, the inductive and steric constants

Electronegativity in the Density Functional Theory. Determination of the Electron Chemical Potential of the Ground State of a System in the Local Density Approximation

An iterative algorithm for simultaneous determination of the ground-state electron chemical potential and electron density of a multielectron system is formulated in terms of the density functional theory. With the energy potential in the local density approximation as an example it is shown that the equality of the electronegativities of the natural orbitals corresponds to the nonphysical electron density