Electrophilic Aromatic Substitution: theoretical insight into halonium ion self-existence in catalytic system

Abstract

Potential Energy Scan (PES) has already proven to be a powerful tool in computational chemistry to detect critical points in the energy path of a system, such as transition states and local minima/maxima in energy convergence. Previous studies showed a wide application of PES in many different fields of physical-chemical sciences, such as materials, supramolecular, and catalysis chemistry. Moreover, the evaluation of the basic PES algorithms at a reasonably affordable level of theory has in principle revealed good basic statistical relationships that allow further investigations in this research area. Herein, a simple and fast graphical method for accurate PES evaluation was proposed, performed at the PM7 semiempirical level of theory for catalytic systems in electrophilic aromatic substitution processes. The results presented in this case study showed a relative error ranging from 1.5 to 27.1% for most catalytic-electrophiloid systems. The treatment of such systems with PES algorithms led to novel iron(V) species and opened a completely new field in tandem transition metal-nonmetal catalysis, implying entirely new insights. Moreover, the basic statistical analysis showed that there are no significant outliers, and therefore it can be concluded that the graphical analysis approach can be used in further detailed treatment of PES results in the search for saddle points and prediction of transition state properties under known conditions in the DFT and MP2 functions discussed here. The novel graphical methodology has been introduced by two applied graphical methods, and its accuracy demonstrated in semiempirical methods provides solid results in view of future development and application in a wide range of chemical sciences.