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Controlled Interconversion of a Dinuclear Au Species Supported by a Redox‐Active Bridging PNP Ligand Facilitates Ligand‐to‐Gold Electron Transfer
Author(s) -
Vreeken Vincent,
Siegler Maxime A.,
van der Vlugt Jarl Ivar
Publication year - 2017
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201700360
Subject(s) - chemistry , redox , ligand (biochemistry) , non innocent ligand , bridging ligand , reactivity (psychology) , metal , electron transfer , photochemistry , combinatorial chemistry , stereochemistry , inorganic chemistry , organic chemistry , medicine , biochemistry , receptor , alternative medicine , pathology
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.