Further studies of [Ni4(DAniDANy)4] (DAniDANy2− = N,N’-bis-p-anisyl-2,7-diamido-1,8-naphthyridine) and its one-electron oxidation product: Metal-metal sigma bonding in Ni49+ complex

The linear tetranickel strings, [Ni4(DAniDANy)4] (1), and its one-electron oxidation product, [Ni4(DAniDANy)4](PF6) (2), have been synthesized and studied extensively (DAniDANy2− = N,N’-bis-p-anisyl-2,7-diamido-1,8-naphthyridine). Crystal structural analyses and DFT calculations suggest that the chemical oxidation of 1 involves removal of an electron from the σ* antibonding orbital, which results in the formation of Ni-Ni bonds in 2.