Stable mixed-valence octanickel (I/II) tris-naphthyridyldiamido complexes

Stable Nickel(I) complexes are rare, however, air stable collinear octanickel (I/II) complexes (4), (5) and (6) have been synthesized successfully by using the novel multidentate ligand trisnaphthyridyldiamine (2, H2tnda). The physical properties and the X-ray single crystal structures of these metal complexes have been characterized. The structures exhibit their corresponding redox relationships and reveal that the nickel centers are arranged linearly through the helical coordination of four ligands (2).