Synthesis of halogeno, pseudohalogeno, and carboxylatopalladium(IV) complexes by halogen exchange. Crystal structure of azido(2,2'-bipyridyl)- benzylpalladium(II), formed on reductive elimination of ethane from Pd(N3)Me2(CH2Ph)(bpy)

The first examples of fluoro, pseudohalogeno, and carboxylatopalladium(IV) complexes have been obtained by the exchange of the bromo ligand in PdBrMe2(CH2Ph)(bpy) (bpy = 2,2'-bipyridyl) on addition of a silver salt, or silver nitrate and the appropriate anion, in acetonitrile. The syntheses have permitted a study of the effect of groups X on the selectivity in reductive elimination of ethane and ethylbenzene from PdXMe2(CH2Ph)(bpy). For X = Br, N3, SCN, or O2CPh, reductive elimination from the unstable palladium(IV) complexes in acetone gives ethane and PdX(CH2Ph)(bpy) only, but these products together with ca. 10% of ethylbenzene and PdXMe(bpy) are formed from the complexes PdXMe2(CH2Ph)(bpy) (X = F, Cl, I, OCN, SeCN, O2CCF3). The binding mode of the ambidentate pseudohalides OCN-, SCN- and SeCN- has not been determined.