Some Studies On Bonding, Reactivity, Aromaticity And Toxicity:A Conceptual DFT Approach: Ever since Thomas and Fermi introduced the electron density as a basic variable to express the total energy as an alternative way to the wavefunction approach, researchers are devoted to formulate the various theories based on the electron density. The density functional theory (DFT) has come into the fore through the landmark work by Hohenberg and Kohn in 1964. In this thesis various reactivity descriptors based on DFT, e.g. electronegativity, hardness, polarizability, electrophilicity etc. and their associated electronic structure principles, e.g. electronegativity equalization principle, maximum hardness principle, minimum polarizability principle, minimum electrophilicity principle etc. are applied to understand the bonding, reactivity, stability, aromaticity and toxicity of diverse classes of chemical compounds. Behavior of the various DFT based local reactivity descriptors along the reaction path of different thermochemical reactions is analyzed. Stability, reactivity and aromaticity of the all-metal aluminum and beryllium clusters are analyzed using DFT and some new all-metal complexes are predicted. The usefulness of the various all-metal species in the field of molecular electronics is analyzed. Stability and aromaticity in the polyacene analogues of various inorganic ring compounds are investigated and the validity of different DFT based electronic structure principles is tested. Various quantum chemical descriptors based on DFT, e.g. electrophilicity index, philicity etc. are developed to explain the toxicity of diverse classes of aliphatic and aromatic compounds including the highly toxic polyaromatic hydrocarbons (PAHs) on ciliated protozoa Tetrahymena pyriformis and Ah receptor in rat liver. Biological activity of male and female hormones, viz. testosterone and estrogen derivatives are modeled successfully using electrophilicity index and the number of atoms in a molecule.
DEBESH RANJAN ROY, Guide:PROFESSOR PRATIM KUMAR CHATTARAJ and CO-GUIDE: DR. VENKATESAN SUBRAMANIAN, DEPARTMENT OF CHEMISTRY, INDIAN INSTITUTE OF TECHNOLOGY, KHARAGPUR, 2008