Cálculos de química quântica para funções orgânicas.

Abstract

Organic-physical chemistry is an area that can contribute to the development of new compounds and the understanding of chemical reactions and processes based on quantum chemistry calculations. One of the concepts addressed in this area is the structure-activity relationship of a functional group, an atom or grouping of atoms connected in a specific way in a molecule, providing reactivity and specific chemical and physical properties. Based on this, this work has the general objective of classifying organic functions through intrinsic properties of functional groups with the increase of the carbonic structure. With the aid of molecular computational models, properties were obtained for the following organic functions, in an attempt to classify them: alkanes; alkenes; alkynes; carboxylic acids; aldehydes; ketones; esters; amines and amides. Some of the properties calculated were: Total electronic energy; molar volume; Energy of the HOMO and LUMO orbitals; gap HOMO-LUMO; Kinetic energy of the HOMO and LUMO orbitals; Ionization Energy; Electroaffinity and Electronegativity. The Ionization Energy properties; Electroaffinity and Electronegativity were obtained indirectly from other properties. It was observed that some properties are more satisfactory in the classification of some organic functions. Furthermore, it was possible to establish mathematical relationships that show a pattern for different organic functions: alkanes, carboxylic acids, esters, aldehydes, ketones and amides. However, for alkenes, alkynes and amines another pattern of behavior was noted. Furthermore, the classification of organic functions is more suitable using the energies of the HOMO and LUMO orbitals. In addition, other properties are also good candidates, such as Electronic Energy, Ionization Energy, Electroaffinity and Electronegativity. Finally, alkenes, alkynes and amines had a greater prominence due to having unique behaviors for many calculated properties.