Hydrogen transfer reaction: Bond formation and bond cleavage through the eyes of interacting quantum atoms

Abstract

Hydrogen transfer from hydroquinone to the methoxy radical was studied using the density functional theory. The energy decomposition technique, interacting quantum atoms, was employed for a detailed investigation of the changes that the bonds of interest go through along the minimum energy path in the vicinity of the transition state. The whole system was divided either into two or three fragments. The two-fragment analysis enabled investigation of the bond that is formed or the one that is cleaved by defining the fragments as reactants and as products, respectively. The three-fragment analysis (the fragments being semiquinone, hydrogen atom and methoxy radical) was used for the simultaneous analysis of the two phenomena, bond cleavage and bond formation. Additionally, it enabled the interaction between the particle that donates the hydrogen atom and the one that accepts it to be investigated. This interaction is characterized by attractive non-classical and repulsive classical interactions. It was demonstrated that the transferring hydrogen atom undergoes the most pronounced energy changes and gives the largest contribution to the deformation energy.

Proton leap: shuttling of protons onto benzonitrile

“…Some of us 73 recently applied the interacting quantum fragments procedure to analyze hydrogen abstraction from hydroquinone by methoxy radical. Depending on the choice of the fragments, the reaction advancement was investigated either from the viewpoint of the reactants or the products.…”

Hydroboration of imines: intermolecularvs.intramolecular hydride transfer

“…IQA 13 is an energy decomposition procedure which was successfully applied on diverse systems, [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] whereas REG approach 31 enables identification of IQA energy components that drive the studied process. [31][32][33][34][35][36][37][38][39][40][41][42][43] We performed a thorough investigation according to two mechanisms: a rearrangement within a single imine-BH 3 species, and hydride transfer which involves two adducts. Additionally, the influence of substituents' size on the corresponding barrier heights is studied.…”

The performance of exchange—correlation functionals in describing electron density parameters of saddle point structures along chemical reactions

“…Furthermore, there is a recent effort in analyzing reactions using the Interacting Quantum Atom (IQA) tools, 16,17 as represented by the studies from Milovanović et al, 18 focused on hydrogen transfer processes, from Viegas and Jensen, 19 who considered tropospheric reactions between the OH radical and α,ω‐dihydrofluoropolyethers, and also from López‐Fernández and collaborators, 20 investigating the Curtius rearrangement. Another example is illustrated by the work of Alkorta et al, 21 which uses the IQA partition for SN2 reactions with halogens.…”