Reactions of 3,5,8-tris(polyfluoroalkyl)-2,6,7-trioxa-1,4-diphosphabicyclo[2.2.2]octanes with electrophilic reagents

3,5,8-Tris(polyfluoroalkyl)-2,6,7-trioxa-1,4-diphosphabicyclo-[2.2.2]octanes were found to react with chlorine and bromine to form adducts at the phosphite phosphorus that are stable below -600C and have a dihalophosphorane structure. The stabilization of pentacoordinated phosphorus in these compounds is due to the increased electron acceptor properties of the bicyclooctane segment with polyfluoroalkyl substituents as compared with acyclic polyfluoroalkoxy substituents. The thermal stability of bicyclic dihalophosphoranes increases with increasing bulk of the polyhaloalkyl groups in the bicyclooctane segment. This follows from comparison of the polyfluoroalkyl phosphoranes with the dihalophosphoranes obtained from 3,5,8-tris(trichloromethyl)-2,6,7-trioxa-1,4-diphosphabicyclo-[2.2.2]octane