Transition Metal Complexes Bearing a Phosphenium Ligand

Abstract

Publisher Summary Many cationic phosphenium complexes have been investigated because a phosphenium may serve as a σ-donor and also as a π-acceptor due to the lone pair electrons and a vacant p orbital. [L n M(PR 2 )], being an electrically neutral transition metal complex, is sometimes treated as a phosphenium complex because it can consist of L n M - and PR 2 + . This chapter focuses on electrically cationic transition metal complexes described as [L n M(PRR′)] + . A phosphenium cation is a two-coordinate phosphorus compound with a high degree of cationic charge accumulation at the phosphorus center. Phosphines and their derivatives are known to be very useful ligands toward transition metals and a variety of complexes with phosphine as a ligand have been prepared for all kinds of transition metals. The chapter also shows some interesting reactivities involving 1, 3-OR, -SR, and -NR2 migration from a tertiary phosphorus ligand to phosphenium P, 1,2-alkyl migration from a transition metal to phosphenium P, and 1,3-alkyl migration from a stannyl ligand to phosphenium P.