Synthesis and characterization of diiridium complexes with a pi-conjugated nanowire chain.

The reaction of the iridium dimer [Ir(ppy)2(micro-Cl)]2 (ppy = 2-pyridiylphenyl) with bis(2,2'-bipyridin-5-yl) ethyne (bpy-C2-bpy), bis(2,2'-bipyridine)-butadiyne (bpy-C4-bpy), and bis(2,2'-bipyridin-5-yl-(Z)-hexa-3-ene-1,5-diyl) (bpy-C6H2-bpy) affords the following diiridium complexes: [ClO4]2 [(ppy)2Ir(bpy-C2-bpy)Ir(ppy)2] (1), [ClO4]2 [(ppy)2Ir(bpy-C4-bpy)Ir(ppy)2 (2), and [ClO4]2 [(ppy)2Ir(bpy-C6H6-bpy)Ir (ppy)2 (3), respectively. Herein, we describe the synthesis, characterization, and physical and electrochemical properties of the diiridium complexes in which the two iridium units are connected by a pi-conjugated nanowire bridge.