Ligand effects on the structure, mixed-valence sites and magnetic properties of novel pentanickel string complexes.

We report the syntheses, characterization, electronic structures and magnetic properties of four redox pairs of novel nickel-extended metal-atom chain (EMAC) complexes containing pyridine-, naphthyridine- and sulfonyl-containing ligands (HTspnda and HMspnda) (1-2 and 5-6). We further study the corresponding phenyl-substituted ligands (HTsphpnda and HMsphpnda) (3-4 and 7-8) to examine the details of ligand effects. The X-ray structure of one-electron-reduced [Ni] complexes shows shorter Ni-Ni bond distances (2.