Examinando por Autor "Guerra, Cristian"
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Ítem A simple topology-based model for predicting the activation barriers of reactive processes at 0 K(Royal Society of Chemistry, 2023-05) Ayarde-Henríquez, Leandro; Guerra, Cristian; Duque-Noreña, Mario; Chamorro, EduardoThis work reveals an underlying correlation between the topology and energetic features of matter configurations/rearrangements by exploiting two topological concepts, namely, structural stability and persistency, leading thus to a model capable of predicting activation energies at 0 K. This finding provides some answers to the difficulties of applying Thom's functions for extracting energetic information of rate processes, which has been a limitation for exact, biological, and technological sciences. A linear relationship between the experimental barriers of 17 chemical reactions and both concepts was found by studying these systems’ topography along the intrinsic reaction coordinate. Such a procedure led to the model , which accurately predicts the activation energy in reacting systems involving organic and organometallic compounds under different conditions, e.g., the gas-phase, solvent media, and temperature. This function was further recalibrated to enhance its predicting capabilities, generating the equation for this procedure, characterized by a squared Pearson correlation coefficient (r2 = 0.9774) 1.1 times higher. Surprisingly, no improvement was observed.Ítem Elucidating the N−N and C−N Bond-breaking Mechanism in the Photoinduced Formation of Nitrile Imine(John Wiley and Sons Inc, 2023-06) Guerra, Cristian; Ayarde-Henríquez, Leandro; Rodríguez-Núñez, Yeray A.; Ensuncho, Adolfo; Chamorro, EduardoIn this study, we revealed the significance of chemical bonding for the photochemically induced mechanism of 2-phenyl tetrazole derivatives generating nitrile imines. The correlated electron localization function shows that the formation of imine nitrile involves two key bond events: (i) the heterolytic C−N breakage taking place in the T1 state and (ii) the homolytic N−N rupture occurring in the T2 excited state. In particular, a cation-radical specie results from the C−N cleavage, whereas the N−N rupture creates a biradical resonant form of imine nitrile. Additionally, we noticed that the substantial pair delocalization of the C−C-N bonded structure could play a significant role in the conversion of the biradical imine nitrile into both the propargylic and allenic forms via the T1→S0 deactivation. © 2023 The Authors. ChemPhysChem published by Wiley-VCH GmbH.Ítem Revisiting the bonding evolution theory: a fresh perspective on the ammonia pyramidal inversion and bond dissociations in ethane and borazane(Royal Society of Chemistry, 2023-10-04) Ayarde-Henríquez, Leandro; Guerra, Cristian; Duque-Noreña, Mario; Chamorro, EduardoThis work offers a comprehensive and fresh perspective on the bonding evolution theory (BET) framework, originally proposed by Silvi and collaborators [X. Krokidis, S. Noury and B. Silvi, Characterization of elementary chemical processes by catastrophe theory, J. Phys. Chem. A, 1997, 101, 7277-7282]. By underscoring Thom's foundational work, we identify the parametric function characterizing bonding events along a reaction pathway through a three-step sequence to establish such association rigorously, namely: (a) computing the determinant of the Hessian matrix at all potentially degenerate critical points, (b) computing the relative distance between these points, and (c) assigning the unfolding based on these computations and considering the maximum number of critical points for each unfolding. In-depth examination of the ammonia inversion and the dissociation of ethane and ammonia borane molecules yields a striking discovery: no elliptic umbilic flag is detected along the reactive coordinate for any of the systems, contradicting previous reports. Our findings indicate that the core mechanisms of these chemical reactions can be understood using only two folds, the simplest polynomial of Thom's theory, leading to considerable simplification. In contrast to previous reports, no signatures of the elliptic umbilic unfolding were detected in any of the systems examined. This finding dramatically simplifies the topological rationalization of electron rearrangements within the BET framework, opening new approaches for investigating complex reactions. © 2023 The Royal Society of Chemistry.