%0 Journal Article
%T Theoretical Calculations and Modeling for the Molecular Polarization of Furan and Thiophene under the Action of an Electric Field Using Quantum Similarity
%A Alejandro Morales-Bayuelo
%A Ricardo Vivas-Reyes
%J Journal of Quantum Chemistry
%D 2014
%R 10.1155/2014/585394
%X A theoretical study on the molecular polarization of thiophene and furan under the action of an electric field using Local Quantum Similarity Indexes (LQSI) was performed. This model is based on Hirshfeld partitioning of electron density within the framework of Density Functional Theory (DFT). Six local similarity indexes were used: overlap, overlap-interaction, coulomb, coulomb-interaction, Euclidian distances of overlap, and Euclidean distances of coulomb. In addition Topo-Geometrical Superposition Algorithm (TGSA) was used as a method of alignment. This method provides a straightforward procedure to solve the problem of molecular relative orientation. It provides a tool to evaluate molecular quantum similarity, enabling the study of structural systems, which differ in only one atom such as thiophene and furan (point group ) and cyclopentadienyl molecule (point group ). Additionally, this model can contribute to the interpretation of chemical bonds, and molecular interactions in the framework of the solvent effect theory. 1. Introduction In chemistry the concept of molecular polarization is a key concept often used to rationalize a lot of molecular properties on the basis of their constituent atoms, geometry, or functional groups. Polarizability allows us to make qualitative judgements about structure and translate them into first approximation of expected properties and chemical reactivity. We can expect, for example, that electrophiles to attack positions with relatively high electron density and polarizability. Nucleophiles should attack relatively low electron density and polarizability. Thus a lot of properties such as boiled point, solubility, melting point, softness, and molecular reactivity depend on its polarizability properties. In this study we related quantum molecular similarity to the molecular polarity, in order to find a theoretical model. Thiophene and furan molecules (point group ) and cyclopentadienyl molecule (point group ) were taken as model of this application. In this contribution a local similarity index based on the Hirshfeld partitioning technique was used [1]. This approach provides a tool to evaluate molecular quantum similarity, enabling the study of structural systems, which differ in only one atom. One of the carbon-carbon (C每C) bonds of the cyclopentadienyl and (C每S) bond from thiophene and (C每O) bond of furan were taken as molecular fragments; these three fragments (C每S, C每O, and C每C) were approximated as diatomic molecule. Taking into account this idea which proposed a theoretical model allows us to relate the
%U http://www.hindawi.com/journals/jqc/2014/585394/