Theoretical reactivity indices based on the conceptual Density Functional Theory (DFT) have become a powerful tool for the semiquantitative study of organic reactivity. A large number of reactivity indices have been proposed in the literature. Herein, global quantities like the electronic chemical potential μ, the electrophilicity ω and the nucleophilicity N indices, and local condensed indices like the electrophilic P k + and nucleophilic P k − Parr functions, as the most relevant indices for the study of organic reactivity, are discussed.

Applications of the Conceptual Density Functional Theory Indices to Organic Chemistry Reactivity.

A Calculation of Atomic Structures. By D. R. Hartree Pp. xiii, 181. 40s. 1957. (Wiley, New York)

Building upon our recent studies devoted to the bonding changes in polar reactions [RSC Advances, 2012, 2, 1334 and Org. Biomol. Chem., 2012, 10, 3841], we propose herein two new electrophilic, P+k, and nucleophilic, P−k, Parr functions based on the spin density distribution at the radical anion and at the radical cation of a neutral molecule. These local functions allow for the characterisation of the most electrophilic and nucleophilic centres of molecules, and for the establishment of the regio- and chemoselectivity in polar reactions. The proposed Parr functions are compared with both, the Parr–Yang Fukui functions [J. Am. Chem. Soc. 1984, 106, 4049] based on frontier molecular orbitals, and Yang–Mortier condensed Fukui functions [J. Am. Chem. Soc. 1986, 108, 5708] based on Mulliken charges.

Understanding the local reactivity in polar organic reactions through electrophilic and nucleophilic Parr functions

This review describes the current state of magnetic criteria of aromaticity. The introduction contains the fundamentals of ring currents in aromatic and antiaromatic systems, followed by a brief description of experimental and computational tools: NMR, diamagnetic susceptibility exaltation, current density analyses (CDA) and nucleus independent chemical shifts (NICS). This is followed by more comprehensive chapters: NMR – focusing on the work of R. Mitchell – NICS and CDA – describing the progress and development of the methods to their current state and presenting some examples of representative work.

Magnetic criteria of aromaticity

6.1. Molecular Vibrations PR58 6.2. Molecular Internal Rotations PR58 6.3. Chemical Reactions PR58 7. Dynamical Variants PR62 7.1. Quantum Fluid Density Functional Theory PR62 7.2. Atom-Field Interactions PR62 7.3. Ion-Atom Collisions PR62 7.4. Chemical Kinetics PR62 8. Spin Dependent Generalizations PR63 8.1. {N, Ns, v(r b)} Representation PR63 8.2. {NR, N , v(r b)} Representation PR64 9. Conclusions PR65 10. Abbreviations and Symbols of Some Important Subjects/Quantities PR

Update 2 of: Electrophilicity Index

A local reactivity difference index Rk is shown to be able to predict the local electrophilic and/or nucleophilic activation within an organic molecule. Together with the electrophilic and/or nucleophilic behavior of the center k given by the sign, the magnitude of the Rk index accounts for the extent of the electronic activation, a behavior that allows for the use of the Rk index as a measure of the molecular reactivity especially in polar processes.

Understanding local electrophilicity/nucleophilicity activation through a single reactivity difference index

A new electronic structure principle, namely, the principle of electrophilicity equalization, is proposed. A qualitative rationale as well as numerical support for the same is provided. Equalization of electronegativity and hardness implies that of electrophilicity. Molecular electrophilicity may be expressed roughly as the geometric mean of the electrophilicities of the isolated atoms.

Electrophilicity Equalization Principle

A new electronic structure principle, viz., the principle of electrophilicity equalization is proposed. An analytical justification as well as a numerical support for the same is provided.

The electron affinity, electronegativity, and electrophilicity of several neutral atoms and their positive and negative ions are calculated at various levels of theory using different basis sets in the gas phase as well as in the presence of solvent and counterions. The electron affinity and electronegativity of all of the anions and dianions are negative in gas phase, and accordingly the electrophilicity is unexpectedly large vis-a-vis its quadratic definition. Many of these trends get altered in case the effects of solvent and counterions are taken into account.

Soma Duley

Papers

Update 2 of: Electrophilicity Index

Understanding local electrophilicity/nucleophilicity activation through a single reactivity difference index

Electrophilicity Equalization Principle

Electrophilicity Equalization Principle

Electron Affinity, Electronegativity, and Electrophilicity of Atoms and Ions†