Generation of H2 from 2-fluoroaziridine plus ammonia catalysed by an oriented external field

Abstract

In recent years, the use of oriented external electric fields (OEEF) has been investigated for its effect in reactivity and selectivity of chemical reactions. It is stated in the literature that orienting the electric field in reaction axis (axis where the electrons change from reactants-like to products-like) would catalyse or inhibit the reaction depending on the orientation along this axis. However, OEEF not only produces catalytic effects, but also has been reported it changes the mechanism of reactions, controls the selectivity of the reactions, and induce conformational rearrangements. The main goal is to gain insight of the effects of OEEF in a specific organic reaction. The focus will be about the catalytic effects and therefore the method reported in the literature will be followed. To do so, first the reaction profile will be studied in an unperturbed state. The optimized structure of both reactants and product will be computed so this way the minima associated with the potential energy surface (PES) are obtained. The next step will be to find the corresponding TS of the reaction and finally carry out intrinsic reaction coordinate (IRC) calculations to build the reaction path. The same procedure will be done, applying increasing values of strength field (negatives and positives) in the direction that corresponds to reaction axis. At this point the results obtained at each magnitude will be compared to the unperturbed state and in this way the main differences will be found and discussed. The reaction selected for this work is an SN2 of ammonia attacking a 2-fluoroaziridine where the nitrogen will be the leaving group. The ring opening of fluoroaziridines by nucleophiles is a method of great interest due to his applications in the synthesis of fluorinated organic compounds that are so important in industries such as pharmaceutical. This potential together with its size has made it suitable for this work. The results have shown a more complex reaction than just an SN2, that leads to unexpected products. Although the catalysis was the initial focus of this work, the rationalization of the OEEF in chemical reactions under Valence Bond Theory will conduce to a more complex discussion of the effects computationally observed here