ROLE OF TUNNELING OF HYDROGEN IN THE NORRISH TYPE-II PROCESSES IN A THIONE AND A KETONE

Intra-molecular hydrogen abstraction reactions were examined in pentan e-2-thione in its lowest triplet state using the AM-1 semiempirical mo lecular orbital method with the geometry optimisation in the unrestric ted Hartree-Fock frame. Results were compared with those of pentane-2- one. The role of tunneling of hydrogen was examined in both the conven tional transition-state approach and in the RRKM theory of unimolecula r reactions. Results reveal that tunneling of hydrogen is less signifi cant to sulfur than to oxygen. (C) 1998 Elsevier Science S.A. All righ ts reserved.