N-Atom transfer via thermal or photolytic activation of a Co-azido complex with a PNP pincer ligand.

Thermal or photolytic activation of well-defined mononuclear [Co(N3)(PNP)] (PNP = 2,2'-bis(diisopropylphosphino)-4,4'-ditolylamido) results in the structurally characterized dinuclear species [Co(μ-N;κ3-P,N,N-PNPN)]2 (3), with two N-bridging phosphiniminato bridgeheads. Density Functional Theory (DFT) calculations indicate the intermediacy of a mononuclear cobalt-nitrido complex, followed by N-migratory insertion into a Co-P bond. Reaction of 3 with two equiv. HCl leads to rupture of the dimer with formation of mononuclear [CoCl(PNPNH)] (4) by protonation of the N-bridges.