Synthesis and Characterization of Linear and Square-Planar Nickel Complexes with Primary Amido Ligands

The synthesis and characterization of the two homoleptic mononuclear nickel complexes (2,6-Dipp2C6H3NH)2Ni (1) and [2-C(H)NDippC6H4NH]2Ni (2) (Dipp = 2,6-Pri2C6H3) are described. 1 is formally two-coordinate and adopts a strictly linear geometry, while 2 features a slightly distorted square-planar geometry. Electrochemistry of 1 and 2 shows that they can be reduced to the corresponding nickel(I) species and oxidized to the corresponding nickel(III) species reversibly or quasi-reversibly. A solid-state magnetic measurement (μeff = 2.79 μB) for paramagnetic 1 indicates the presence of two unpaired electrons on the nickel center.