Inquiry of the electron density transfers in chemical Q1 Q2 reactions: a complete reaction path for the denitrogenation process of 2,3-diazabicyclo- 2.2.1hept-2-ene derivatives

摘要

A detailed study on all stages associated with the reaction mechanisms for the denitrogenation of2,3-diazabicyclo[2.2.1]hept-2-ene derivatives (DBX, with X substituents at the methano-bridge carbon atom,X = H and OH) is presented. In particular, we have characterized the processes leading to cycloalkenederivatives through migration-type mechanisms as well as the processes leading to cyclopentil-1,3-diradicalspecies along concerted or stepwise pathways. The reaction mechanisms have been further analysed withinthe bonding evolution theory framework at B3LYP and M05-2X/6-311+G(2d,p) levels of theory. Analysis ofthe results allows us to obtain the intimate electronic mechanism for the studied processes, providing a newtopological picture of processes underlying the correlation between the experimental measurementsobtained by few-optical-cycle visible pulse radiation and the quantum topological analysis of the electronlocalization function (ELF) in terms of breaking/forming processes along this chemical rearrangement. Theevolution of the population of the disynaptic basin V(N1,N2) can be related to the experimental observationassociated with the NQN stretching mode evolution, relative to the N2 release, along the reaction process.This result allows us to determine why the N2 release is easier for the DBH case via a concerted mechanismcompared to the stepwise mechanism found in the DBOH system. This holds the key to unprecedentedinsight into the mapping of the electrons making/breaking the bonds while the bonds change.