Computational chemistry: a tool to studies of mass spectrometry, reactivity and fragmentation/reaction mechanisms of organic compounds

Abstract

In recent years, the gas-phase chemistry has been the subject of numerous scientific papers and has climbed prominence due to two main events. The development of computational models, improvement of existing ones and advances in data processing, allowing obtaining thermochemical quantities with high accuracy. and the development of current mass spectrometry analysis (MS), which allowed the ionization of molecules, sequential analysis and ion-molecule reaction. The combination between these events has become a useful tool for the growth of many areas of modern chemistry, which further contributes to the understanding of phenomena, per hour, unknown. The computational chemistry in combination with mass spectrometry allows comprises several chemical events which may occur during the ionization and dissociation of a particular compound, through appropriated descriptors, for instance, gas-phase basicity, proton affinities, electron affinities and proton transfers. A provides a quantitative understanding of the structural and energy variations of the ions formed during the possible ionization of the sample, and also the possible pathways of dissociation of ions formed by collision-induced dissociation (CID), thus the indicative of intermediates and transition states. The current project aims developed through the application of current mass spectrometry techniques, such as electrospray ionization (ESI) in combination with computational chemistry for understanding of the reactivity of organic molecules in the gas phase and its mechanisms of fragmentation, thus interpreting their spectra MS/MS by combination with energy, geometric and topological data, which will contribute to the expansion of the results described in the literature and its application by non-specialists and users of different ionization techniques. Nevertheless, the results will be combined with pka values obtained from computational methods in order to suggest the reactivity of compounds in solution. (AU)