REDOX BEHAVIOR OF FERROCENE DERIVATIVES .8. 1,1'-BIS(DIPHENYLPHOSPHINO) FERROCENES

A study has been made of the possibility of increasing the stability o f the 1,1'-bis(diphenylphosphino)ferrocenium monocation by introductio n of appropriate substituents into the cyclopentadienyl ligands. The e lectrochemical behaviour of a series of 1,1-bis(diphenylphosphino)ferr ocenes bearing substituents with a range of electronic properties has been examined. The results reveal that, the higher the electron-donati ng ability of the substituents, the longer is the lifetime of the corr esponding 1,1'-bis(diphenylphosphino)ferrocenium monocation. However, no stable ferrocenium cation has been obtained; mass spectrometry show s that mixtures of mono- and di-bis(diphenylphosphine)oxides are ultim ately formed as products resulting from decomposition of the initially electrogenerated 1,1'-bis(diphenylphosphino)ferrocenium species.