Nitrogen–Nitrogen Bond Formation via a Substrate-Bound Anion at a Mononuclear Nickel Platform

The
nickel-C4F8 fragment coordinates an aminoaryl
N–H ketimine to form a stable complex, which upon treatment
with base and oxidant leads to an N–N bond-forming reaction
and the release of indazole product. A key and previously unidentified
intermediate in the formation of the indazole was a diimine complex
of nickel bearing significant charge on the aryl ring that initially
contained the amine substituent. The C4F8 coligand
was key for the redox transformation and for stabilization of the
intermediate for characterization.