High-valent Pd coordination compounds

In summary, we have provided a comprehensive overview of the structurally characterized Pd^III and Pd^IV complexes that have been isolated and characterized by various groups since 2003. This chapter showcases the first reported organometallic dinuclear Pd^III complexes, published in 2006, and the first mononuclear organometallic Pd^III complexes, published in 2010. Brief synthesis methodologies, structural properties, and the reactivity of these organometallic complexes have also been discussed. Furthermore, we also included various examples of dinuclear and molecular 1D chain bearing Pd^III backbones that have been well-characterized using X-ray crystallography and traditional spectroscopic techniques. We have also discussed the strategies employed behind the isolation of Pd^IV complexes, which have been proposed as intermediates in various organic transformations. A range of ligand frameworks have been successfully employed to arrest the reductive elimination reactions which usually limit the stability of these Pd^IV complexes. Overall, the judicious choice of chelating ligands and their steric and electronic properties seems to be paramount for the stabilization of such high-valent Pd complexes. Moreover, we expect that the structural insights gained from the detailed characterization of these intermediates will lead to the development of more specific uses of high-valent Pd species in catalysis and other applications.