Controlled Interconversion of a Dinuclear Au Species Supported by a Redox‐Active Bridging PNP Ligand Facilitates Ligand‐to‐Gold Electron Transfer

Redox non‐innocent ligands have recently emerged as interesting tools to obtain new reactivity with a wide variety of metals. However, gold has almost been neglected in this respect. Here, we report mechanistic investigations related to a rare example of ligand‐based redox chemistry in the coordination sphere of gold. The dinuclear metal‐centered mixed‐valent Au(I)–Au(III) complex 1, supported by monoanionic diarylamido‐diphosphine ligand PNP(Pr) and with three chlorido ligands overall, undergoes a complex series of reactions upon halide abstraction by silver salt or Lewis acids such as gallium trichloride. Formation of the ultimate Au(I)–Au(I) complex 2 requires the intermediacy of Au(I)–Au(I) dimers 5 and 7 as well as the unique Au(III)–Au(III) complex 6, both of which are interconverted in a feedback loop. Finally, unprecedented ortho‐selective C−H activation of the redox‐active PNP ligand results in the carbazolyldiphosphine derivative PN*P(Pr) via ligand‐to‐metal two‐electron transfer. This work demonstrates that the redox‐chemistry of gold may be significantly expanded and modified when using a reactive ligand scaffold.