η1-alkynyl chemistry for the higher oxidation states of palladium and platinum

Abstract

This chapter reviews the organometallic chemistry of palladium and platinum, in which the metal atom is bonded to alkynyl ligands and the formal oxidation state of the metal atom is greater than two. Several synthetic methods have been reported, where the most generally applicable involve oxidation of alkynylmetal(II) complexes and reactions of organometal(II) complexes with alkynyl(aryl)iodine(III) reagents. Metal(IV) complexes obtained have octahedral geometry and some have been shown to decompose via reductive elimination reductive elimination processes to generate carbon-carbon bonds. Unsymmetrical metal-metal bonded species formally represented as PtIII-Pt III ↔ PtIV-PtII have been characterised as intermediates in oxidation of PtII to PtIV. Potential implications for mechanisms of organic reactions mediated by higher oxidation state metal centres are discussed. © 2011 Springer-Verlag Berlin Heidelberg.