Radiotracers in fluorine chemistry. Part IV. Fluorine-18 exchange between labelled alkylfluorosilanesand fluorides, or fluoride methoxides, of tungsten(VI), molybdenum(VI), tellurium(VI), and iodine(V)

Abstract

Exchange of ¹⁸F between labelled alkylfluorosilanes and fluoride methoxides gives the sequences of rates WF₆ < WF₅(OMe) WF₄(OMe)₂ > WF₃(OMe)₃ > WF₂(OMe)₄, MoF₆ MoF_6–n(OMe)_n, (n= 4 or 5), and IF₄(OMe) > IF₅. Exchange with tellurium compounds is too slow to measure. An associative mechanism is proposed for the ¹⁸F-exchange reactions, and the exchange reactions are compared with similar substitution reactions.