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(N 3)Me 2(CH 2Ph)(bpy)

Abstract

The first examples of fluoro, pseudobalogeno, and carboxylatopalladium(IV) complexes have been obtained by the exchange of the bromo ligand in PdBrMe 2(CH 2Ph)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 PdXMe 2(CH 2Ph)bpy). For X  Br, N 3, SCN, or O 2CPh, reductive elimination from the unstable palladium(IV) complexes in acetone gives ethane and PdX(CH 2Ph)(bpy) only, but these products together with ca. 10% of ethylbenzene and PdXMe(bpy) are formed from the complexes PdXMe 2(CH 2Ph) (bpy) (X  F, Cl, I, OCN, SeCN, O 2CCF 3). The binding mode of the ambidentate pseudohalides OCN −, SCN − and SeCN − has not been determined.