Energetics of Electron Pairs in Electrophilic Aromatic Substitutions

Abstract

The interacting quantum atoms approach (IQA) as applied to the electron-pair exhaustive partition of real space induced by the electron localization function (ELF) is used to examine candidate energetic descriptors to rationalize substituent effects in simple electrophilic aromatic substitutions. It is first shown that inductive and mesomeric effects can be recognized from the decay mode of the aromatic valence bond basin populations with the distance to the substituent, and that the fluctuation of the population of adjacent bonds holds also regioselectivity information. With this, the kinetic energy of the electrons in these aromatic basins, as well as their mutual exchange-correlation energies are proposed as suitable energetic indices containing relevant information about substituent effects. We suggest that these descriptors could be used to build future reactive force fields.

Designing Dual-Functional Metal–Organic Frameworks for Photocatalysis

“…The HOMO of 4-chlorobenzenethiol is slightly lower than that of benzenethiol, representing a smaller thermodynamic driving force for hole transfer (Figure S19). Moreover, the lower conversion of 4-chlorobenzenethiol could stem from the deactivating nature of halogens in electrophilic aromatic substitution reactions. , Assuming that the reaction proceeds via a thiyl radical, , the Cl-substituent can deactivate the aromatic ring of one radical, making it less susceptible to electrophilic attack by another thiyl radical, and thereby decreasing the overall reactivity and yield. Despite the reduced yield, Pt/UiO-66-pz is selective in producing bis­(dichlorophenyl)­disulfide, and the dual-functional reaction is still successful.…”

Enhancing catalytic efficiency of carbon dots by modulating their Mn doping and chemical structure with metal salts

“…The coordinated anions can affect the formation of the carbogenic domain owing to their different properties (e.g., electron-withdrawing capability) in various reactions, such as aromatic substitution. [59][60][61] As strong withdrawing groups deactivate aromatic substitution, Mn&N-CD_NO 3 might possess a smaller population of sp 2 domains than other Mn&N-CDs. In addition, strong electron-withdrawing groups may inhibit the coordination of metal ions into CD structures.…”

A Lewis Acid Stabilized Ketenimine in an Unusual Variant of the Electrophilic Aromatic Substitution

“…The formal reaction of the ketenimine adduct 1 b ⋅ 2 B (formed upon treatment of 1 a with B(C 6 F 6 ) 3 ) with aromatic solvents such as benzene or toluene affording amino‐malononitrile‐substituted arenes (Scheme 3 bottom) corresponds to a classical electrophilic aromatic substitution (EAS) reaction: The classic S E Ar mechanism starts with the fast formation of π‐complex and the attack of an electrophile E + on the aromatic system, forming a σ‐(Wheland)‐complex stabilized by mesomerism. A deprotonation‐protonation reaction step results in the restoration of the aromatic system (Scheme 3 top) [19–32] . The S E Ar mechanism has been intensively studied recently and is used to explain halogenations, nitration, sulfonation, Friedel‐Crafts substitutions, and others mechanistically [19–33] .…”

“…A deprotonation‐protonation reaction step results in the restoration of the aromatic system (Scheme 3 top). [ 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 ] The S E Ar mechanism has been intensively studied recently and is used to explain halogenations, nitration, sulfonation, Friedel‐Crafts substitutions, and others mechanistically. [ 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 ] Often a catalyst (Lewis acid) is needed to form the electrophile.…”

“…[ 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 ] The S E Ar mechanism has been intensively studied recently and is used to explain halogenations, nitration, sulfonation, Friedel‐Crafts substitutions, and others mechanistically. [ 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 ] Often a catalyst (Lewis acid) is needed to form the electrophile. Just recently, a variety of concerted mechanisms have been found that surprisingly do not involve the formation of σ‐complex intermediates, which is in apparent contradiction to the generally accepted textbook mechanism.…”