A Non-Planar Iodinated Pyrrole Study
- PDF / 637,108 Bytes
- 7 Pages / 612 x 792 pts (letter) Page_size
- 94 Downloads / 174 Views
A Non-Planar Iodinated Pyrrole Study E.A. Valenzuela-Hermosillo1, J.H. Pacheco-Sánchez1 1
División de Estudios de Posgrado e Investigación. Instituto Tecnológico de Toluca. Metepec 52149. México. ABSTRACT Non-planar iodinated pyrrole structures were found through DFT calculations of geometry optimization, when doping one pyrrole molecule with iodine atoms. This take us to a new mono-iodinated pyrrole structure in which one pyrrole molecule is attacked with one iodine atom in a pyramidal configuration. Then, the pyrrole molecule was attacked with two and until four optimized linear iodine atoms in a pyramidal structure configuration. The corresponding potential energy curves were also constructed in order to know what kind of adsorption (physisorption or chemisorption) is obtained, considering physisorption as lower than ten kcal/mol, and chemisorption greater than twenty kcal/mol according to the literature. Finally, it is known that halogenated pyrrole is a highly conductive material required in several fields.
INTRODUCTION In this work, doping (adsorption) a pyrrole molecule with linear iodine atoms perpendicularly to the pyrrole plane is achieved. It is studied by geometry optimization technique based on methods of quantum molecular modeling. Energy calculations are based on the separation distance between pyrrole and a number of iodine atoms ranging from one to four. Potential energy curves were constructed, in order to obtain wells of potential. For this purpose the density functional theory (DFT) was used [1]. It is noteworthy that for the behavior of the potential energy obtained for different structures among iodine and pyrrole atoms, changes in each one were found. When an iodine atom faces a pyrrole molecule, the equilibrium point is 3.2 Å of distance and -8.1 kcal/mol of energy in a pyramidal geometry configuration. When it increased up to two iodine atoms and one molecule of pyrrole, the equilibrium point was found in (3.5 Å, -8.9 kcal / mol). Increasing up to three and four iodine atoms leads to the following equilibrium points: (3.4 Å - 6.6 kcal/mol) and (3.6 Å 8.7 kcal/mol), respectively. Pyrrole (C4H5N) is an aromatic and heterocyclic organic chemical compound, a fivemembered ring having low basicity; when it is doped with another element, in this case iodine, alters its electronic structure [2]. Pyrrole is ionic with an N-H group weakly acidic instead of basic. Activated structures have much lower energy than the activated structures in benzene. Then pyrrole is more reactive than benzene. When pyrrole is treated with bromine, chlorine or iodine, in dilute solution, the mono-alpha derivative is formed first. If excess halogen is used, the tetrahalogenated pyrrole is formed more readily than monohalogenated benzenes [3]. Planar tetrahalogenated pyrrole has been found to be highly conductive [4, 5]
Downloaded from https:/www.cambridge.org/core. University of Arizona, on 25 Apr 2017 at 02:41:22, subject to the Cambridge Core terms of use, available at https:/www.cambridge.org/core/terms. https://doi.
Data Loading...
