Formation of 2‑Azaallyl Cobalt(I) Complexes by Csp3–H Bond Activation

Three novel unsymmetrical η3-2-azaallyl cobalt­(I) complexes, [(2-PPh2)­C6H4]­CHN­[CHC6H4­(4-R)]­Co­(PMe3)2 (4–6) (R = H (4); Cl (5); and OMe (6)), were synthesized by the reactions of Schiff base ligands [(2-PPh2)­C6H4]­CHN­[CH2C6H4­(4-R)] (1–3) (R = H (1); Cl (2); and OMe (3)) with CoMe­(PMe3)4 via sp3 C–H bond activation under mild reaction conditions. Complex {[(2-PPh2)­C6H4]­CHNCH3­[CHC6H4­(4-R)]­Co­(PMe3)2}I (7) as an 18e cobalt­(III) salt was obtained through the reaction of 4 with iodomethane. The substitution reaction of complex 4 with carbon monoxide afforded the dicarbonyl cobalt­(I) complex [(2-PPh2)­C6H4]­CH­[NCHC6H4­(4-R)]­Co­(CO)2­(PMe3) (8). The molecular structures of complexes 4–8 were determined by single crystal X-ray diffraction.