Formal Nickelate(−I) Complexes Supported by Group 13 Ions

Formal nickelate(−I) complexes bearing Group 13 metalloligands (M=Al and Ga) were isolated. These 17 e− complexes were synthesized by one‐electron reduction of the corresponding Ni0→MIII precursors, and were investigated by single‐crystal X‐ray diffraction, EPR spectroscopy, and quantum chemical calculations. Collectively, the experimental and computational data support: 1) the strengthening of the Ni−M bond upon one‐electron reduction, and 2) the delocalization of the unpaired spin across the Ni and M atoms. An intriguing electronic configuration is revealed where three valence electrons occupy two σ‐type bonding interactions: Ni(3dz2 )2→M and σ‐(Ni−M)1. The latter is an unusual Ni−M σ‐bonding molecular orbital that comprises primarily the Ni 4pz and M npz/ns atomic orbitals. Where are the valence electrons? Formally Ni(−I) complexes bearing Group 13 metalloligands were isolated. These complexes feature three‐electron bonding interactions.