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 AuI -AuIII complex 1, supported by monoanionic diarylamido-diphosphine ligand PNPPr 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 AuI -AuI complex 2 requires the intermediacy of AuI -AuI dimers 5 and 7 as well as the unique AuIII -AuIII 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*PPr 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. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

Citation

Vincent Vreeken, Maxime A Siegler, Jarl Ivar van der Vlugt. Controlled Interconversion of a Dinuclear Au Species Supported by a Redox-Active Bridging PNP Ligand Facilitates Ligand-to-Gold Electron Transfer. Chemistry (Weinheim an der Bergstrasse, Germany). 2017 Apr 24;23(23):5585-5594

PMID: 28248000

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