Kinetics of ring opening of propylene sulphide: 1. Alkali metal and cryptated alkali metal carbazyl salts

The reactivities of free ions and ion pairs have been determined for the ring opening of propylene sulphide with carbazyl salts, in THF at ?30°C. A large increase of the ion pair reactivity is observed on increasing the size of the counterion (Na⁺ < Cs⁺ < Na⁺ + |222|). Moreover, cryptated carbazyl ion pairs are three times more reactive than free ions in the same manner as thiolate species for the propagation of propylene sulphide in similar conditions.