The phospha-2-allyl-system: electrochemical and quantum chemical investigations

Electrochemical investigations on some substituted phospha-2-allyl cations are performed. The phospha-2-allyl cation prefers a bent rather than a linear allene-type structure. According to quantum chemical calculations, in the lowest energy doublet state the single electron resides in the non-bonding orbital of the π-system. The electrochemical investigations on some substituted substrates indicate irreversible oxidation to the radical dication as well as one-electron and two-electron reduction to the radical and anion. The various substituent effects as well as the electronic properties of the parent cation, radical and anion and its valence isomers are rationalized by quantum chemical calculations.