Redox-active ligands can induce noble metal reactivity upon base metals by acting as an electron reservoir. However, establishing ‘base metal-like’ odd-electron reactivity with closed-shell noble metals using redox-active ligands is very rare. We introduced novel redox-active tridentate ligand designs that form paramagnetic palladium complexes (S = ½) that undergo reversible ligand-based redox-chemistry. Interestingly, the unpaired electron can be transferred to a bound organic substrate, effectively generating a single-electron reduced substrate in the coordination sphere of PdII. This activated intermediate can subsequently react in an intramolecular fashion following an odd-electron pathway. This exciting feature has been exploited to convert alkyl azides into pyrrolidines for the first time using PdII. Following the same protocol, homolytic bond scission of disulfides gives rise to unique ligand mixed-valent dinuclear species. The magnetic properties of related mono-ligated bridged complexes have also been investigated. This presentation will discuss the concepts and potential of this chemistry, including results on base metal catalyzed C-H amination and Ru-mediated azide activation will also be presented, as well as ongoing work on reactive ligand designs that may work in complementary ways to activate substrates for catalysis. We will also discuss cross-roads between both types of ligand platforms.

Redox-active and reactive ligands - new avenues for organometallic chemistry, selective bond activation and homogeneous catalysis

255th National Meeting (2018)

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