C-H Activation of Benzene by a Photoactivated NiII(azide): Formation of a Transient Nickel Nitrido Complex

Photochemical activation of nickel‐azido complex  2  [Ni(N3)(PNP)] (PNHP=2,2′‐di(isopropylphosphino)‐4,4′‐ditolylamine) in neat benzene produces diamagnetic complex  3  [Ni(Ph)(PNPNH)], which is crystallographically characterized. DFT calculations support photoinitiated N2‐loss of the azido complex to generate a rare, transient NiIV nitrido species, which bears significant nitridyl radical character. Subsequent trapping of this nitrido through insertion into the Ni—P bond generates a coordinatively unsaturated NiII imidophosphorane P=N donor. This species shows unprecedented reactivity toward 1,2‐addition of a C—H bond of benzene to form  3  . The structurally characterized chlorido complex  4  [Ni(Cl)(PNPNH)] is generated by reaction of  3  with HCl or by direct photolysis of  2  in chlorobenzene. This is the first report of aromatic C—H bond activation by a trapped transient nitrido species of a late transition metal