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Theoretical research on the direct carboxylation of benzene with CO 2 catalyzed by different carbene‐CuOH compounds
Author(s) -
Liu Cong
Publication year - 2021
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.4137
Subject(s) - chemistry , carbene , carboxylation , catalysis , reactivity (psychology) , substituent , photochemistry , transition metal carbene complex , medicinal chemistry , steric effects , benzene , carboxylate , organic chemistry , medicine , alternative medicine , pathology
The direct carboxylation between the benzene C–H and CO 2 is a long‐standing challenge in catalysis. Based on the known experimental process for the direct carboxylation of fluorobenzene, herein, a theoretical design of efficient carbene‐copper catalysts for the direct carboxylation of benzene was reported. It was found that the reaction included two steps: C–H bond breaking and CO 2 insertion into Cu‐phenyl. C–H breaking is the rate‐determining step. To find out a more effective catalyst, totally, 16 carbene‐copper compounds with different electronic and steric structures were investigated. The energy barriers for the C–H bond breaking range from 104.2 to 153.7 kJ/mol. Two effective methods are proposed for improving the catalytic reactivity: reducing the electronically active substituent on carbene and introducing interaction to stabilize the transition state (TS). Based on these findings, adopting a well‐known (amino)(silyl)carbene modified by a –NH 2 group gives the most effective catalyst for the direct carboxylation of benzene. Using –NH 2 group can introduce two strong interactions (O OH ···H NH2 and N NH2 ···Cu) during the formation of TS, which can greatly stabilize the structure of TS and dramatically reduce the energy barrier. The catalytic reactivity of the most effective carbene‐copper catalyst is comparable with the noble metal‐based ruthenium pincer carboxylate complexes.