Detection and Properties of Triplet State Thiiranes

Article abstract of DOI:10.1021/j150609a001

The major primary step in the long wavelength (λ > 240 nm) photolysis of the thiirane is intersystem crossing to the lowest excited triplet (T₁) state with a quantum yield of ca. 0.86.Triplet thiirane has a long radiative lifetime, is highly resistant to collisional deactivation, and is capable of undergoing reversible addition to alkenes and thereby including their geometrical isomerization.Inefficient irreversible addition also occurs.This provides a novel example of an excited triplet molecular sensitization not involving energy transfer.Thiirane T₁ has a cyclic structure which is retained in the alkene adduct and shows strong diradical character.