N-Assisted Carbon−Hydrogen Bond Activation by Cobalt(I) Complexes

Reactions of 2-(4′-R-phenylazo)-4-methylphenols (R = Me ( 1 ), Br ( 2 )) with Co(PMe 3 ) 3 Cl afford two organocobalt(III) complexes, Co(PMe 3 ) 2 Cl(Me(C 6 H 3 O∩N═NC 6 H 3 R)·(H 2 NC 6 H 4 R)) (R = Me ( 3 ), Br ( 4 )), whereas the reactions of 1 and 2 with Co(PMe 3 ) 4 and Co(PMe 3 ) 4 Me afford the dinuclear complex [Co 2 (PMe 3 ) 4 (MeC 6 H 3 O ∩ NH) 2 ] ( 7 ) with the cleavage of the N═N bond. Crystal structures of 3, 4, and 7 were determined by X-ray crystallography.