Large Temperature Dependence of Large Kinetic Isotope Effects of Multistep Hydride Reduction of p -Chloranil by NADH Models in Acetonitrile: Proton Tunneling within Loose Radical Ion-Pairs
Year: 2025
Type: article
Abstract: High Resolution Image Download MS PowerPoint Slide The temperature dependence of H/D kinetic isotope effects (KIEs) was determined for electron-transfer initiated multistep hydride-transfer reactions of NADH models in acetonitrile to investigate our hypothesis that more rigid systems exhibit smaller isotopic activation energy differences (Δ E a = E aD – E aH ). Proton-tunneling occurs in close contact or partially solvent-separated radical ion-pair intermediates. Large KIEs and large Δ E a ’s were observed, in contrast to the relatively small KIEs and Δ E a ’s typically observed for one-step mechanisms where hydride-tunneling occurs within much tighter charge-transfer complexes. Results support the hypothesis.
Source: The Journal of Organic Chemistry
Authors: Bibesh Pokhrel, Jessica Sager, Pratichhya Adhikari, Grishma Singh, Bikram Dhakal, Yun Lu
Institution: Southern Illinois University Edwardsville
Language: English
Topic: Chemical Reaction Mechanisms
Subfield: Organic Chemistry
Field: Chemistry
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,500
OpenAlex ID: W4416231338