Experimental and ab initio studies on solid-state hydrogen isotope exchange with spillover tritium

This study utilizes ab initio calculations to investigate the reaction of h igh-temperature solid-state catalytic isotope exchange (HSCIE) between amin o acids and spillover tritium. The Hartree-Fock approximation and second-or der Moller-Plesset perturbation theory in conjunction with 6-31G* and aug-c c-pVDZ basis sets were used to calculate potential energy surfaces for the interactions between CH4, alanine, hydroxyproline, and the H3O+ ion. Ab ini tio calculations were used to estimate the activation energies and structur es of the transition states of these reactions. The hydrogen exchange react ion occurs by a synchronous mechanism, with a transition state that is char acterized by pentacoordinated carbon. The proposed one-center mechanism is in good agreement with observed retention of configuration of the asymmetri c carbon atoms in the HSCIE reaction with spillover tritium in experiments. The regioselectivity and stereoselectivity of hydrogen isotope exchange in amino acids with spillover tritium can be predicted on the basis of ab ini tio calculations of interaction of this compound with a model acidic center , taking the H3O+ ion as an example.