Oxidative Addition Reactions of Bis-Aminophosphine and Bis-Phosphinite Nickel(0) Pincer Complexes

The tridentate ligands S­(CH₂CH₂NHP<i>i</i>Pr₂)₂ and S­(CH₂CH₂OP<i>i</i>Pr₂)₂ undergo C–S oxidative addition to give (SCH₂CH₂EP<i>i</i>Pr₂)­Ni­(CH₂CH₂EP<i>i</i>Pr₂) (E = NH (<b>2</b>), O (<b>4</b>)). The corresponding reaction of the aminophosphine ligand HN­(CH₂CH₂NHP<i>i</i>Pr₂)₂ is reversible, affording access to a transient Ni(0) synthon that undergoes oxidative addition with HCl, MeI, or <i>o</i>-ClC₆H₄F to give the Ni­(II) complexes [HN­(CH₂CH₂NHP<i>i</i>Pr₂)₂NiR]­X (R = H, X = Cl (<b>7</b>), PF₆ (<b>8</b>); R = Me, X = I (<b>9</b>); R = <i>o</i>-C₆H₄F, X = Cl (<b>10</b>)). These observations are supported via computations