Valence non-Lewis density as an approach to describe and measure aromaticity of organic and inorganic molecules.

Based on the linear combination of atomic orbital-molecular orbital by the natural bond orbitals (NBO) theory, the attractive donor-acceptor superposition interaction between filled (Lewis-type) and vacant (non-Lewis-type) orbitals provide a general mechanism for quantal energy lowering. This interaction has a direct impact on the quantity of the second-order stabilization energy. Therefore, the valence non-Lewis density (VNLD) index, the electron density of unoccupied valence nonbonding and antibonding orbitals, is introduced as an approach to describe and measure aromaticity.

Total non-lewis structures: An application to predict the stability and reactivity of linear and angular polyacenes.

In the present work, the total non-Lewis structure (TNLS) is introduced for describing the stability and reactivity of linear and angular polyacenes. TNLS of a molecule is derived from the natural bond orbital theory representing the antibonding orbitals and/or electron delocalization of π orbitals. To verify this application, we obtained the TNLS values of thirteen linear and angular polyacenes and evaluated with other quantitative aromaticity probes based on reactivities, energetics, geometrics, and magnetic properties.

An electronic properties investigation to interpret the substituent constants of monosubstituted benzene derivatives.

In the present work, the π and π-electronic nature of substitution constants (σ) of the twenty-two monosubstituted benzene derivatives (MSBDs) are estimated in terms of the para-delocalization index (PDI) and total non-Lewis structure (TNLS), respectively. Since these compounds are aromatic, the other descriptors of aromaticity such as nuclear independent chemical shifts and aromatic stabilization energy have been examined. Because of no considerable variation for the π and π-electron delocalization in the ring systems, a very weak correlation has been demonstrated between all aromaticity indices.

A simple method for estimating the absolute solvation free energy of monovalent ions in different solvents.

The solvation Gibbs free energies (SGFE) of 39 ions were estimated in protic and aprotic solvents including methanol, ethanol, N,N-dimethylformamide (DMF) and acetonitrile (ACN) using a proposed approach. In this method, the error of the applied computational method, used for estimating the SGFE of a specific ion in water and dimethyl sulfoxide (DMSO) solvents, was used as a reference value to correct the calculated SGFE of the ion in other protic and aprotic solvents, respectively. The estimated values of SGFE of ions, obtained in this work, show good agreement with those obtained using the other methods reported in literature.