Estudo teórico da reação de polimerização do HCN em rotas abiossintéticas dos blocos fundamentais necessários à vida

Abstract

The origin of life is a mystery, making room for ideas and arguments that try to explain how the damage done to our planet. One of the proposals currently in progress is the theory of chemical evolution (EVT), which defends what is the first terrestrial living thing from complex complications, from simple compounds, in an oxygen-free environment. Among these estimates, a polymerization of HCN for the formation of DAMN (diaminomaleonitrile), has a main role in explaining the formation of nitrogenous bases, or nucleic bases, important molecules in the construction and viability of DNA and RNA. Based on this EVT proposal, a molecular modeling of the abiosynthetic routes by the HCN route was performed. Computational calculations for thermodynamic and structural properties were used to assess the spontaneity of the polymerization route. Based on the thermodynamic results obtained, polymerization of HCN, in the gas phase, for the formation of DAMN does not occur spontaneously at room temperature. However, a reaction becomes spontaneous in the initial HCN dimerization stage, there is the presence of HNC as a reagent, at low temperatures. In this context, the presence of the HNC molecule in abiosynthetic routes requires the presence of a non-terrestrial environment - such as the outer space - for its formation, since its natural presence on Earth is impossible due to its high instability. Therefore, it is suggested that HCN polymerization is spontaneous in very specific spatial conditions, and a new route is published in this work. The theoretical model applied suggests that the possibility of formation of DAMN can occur in the liquid phase through the participation of CN- and H + ions. However, complex training requires large amounts of HCN, in specific and controlled environments, capable of generating the necessary conditions to overcome energy barriers of 32 kCal/mol for the formation of the Dimer, and 56 kCal/mol for the formation of the polymer Trimer, to be able to promote as other stages of the abiosynthetic routes.