Binuclear 1,2,4,5-tetraimino-3,6-diketocyclohexane bis[bis(bipyridine)ruthenium(II)] redox series

The reaction of the [Ru(bpy)(2)(MeOH)(2)](2+) cation (bpy = 2,2'-bipyridine) with 1,2,4,5-tetraaminobenzene in the presence of trace water and oxygen yields the cation [(bpy)(2)Ru(1,2,4,5-tetraimino-3,5-diketocyclohexane)Ru(bpy)(2)](4+). This binuclear species undergoes ligand-based reductions, giving the 3+ and 2+ charged species. The X-ray structure, electrochemistry, ZINDO calculations, and NMR, ESR, UV/vis, and IR spectra were analyzed where possible, giving an electronic model of the binuclear species and some of its redox products. The X-ray structure reveals the [(bpy)(2)Ru] fragments symmetrically disposed across the 1,2,4,5-tetraimino-3,5-diketocyclohexane bridge in a molecule with C(s) symmetry.