Secondary Alpha Isotope Effects on Deuterium Tunneling in Triplet o-Methylanthrones:Extraordinary Sensitivity to Barrier Width

摘要

Quantum mechanical tunneling (QMT) has been invoked in reactions that occur under cryogenic conditions,enzymatic processes involving proton and hydride transfer,hydrogen-bonded networks,gas phase,and interstellar chemistry.In the past few years,we have analyzed the structural and electronic factors that affect the rate of photoinduced H-atom tunneling in ortho-methyl ketones prepared with natural abundance (la) and trideuterated methyl groups (Id,Scheme I).