FORMATION OF DINITROGEN BY OXIDATION OF [(BPY)(2)(NH3)RUORU(NH3)(BPY)(2)](4)

The Ru-O bond distance of the bridge in cis,cis-[(bpy)(2)(NH3)RuORu(NH 3)(bpy)(2)](4+) (2) is 1.8939(15) Angstrom, the Ru-O-Ru angle is 158.2 (4)degrees, the N1(ammonia)-Ru-Ru-N1(ammonia) torsional angle is 28.45 degrees, and the distance between the N atoms of the ammines is 4.816 Angstrom. Electrochemical oxidation of 2 in acid gives N-2 and oxidiz ed forms of cis, cis-[(bpy)(2)(H2O)(RuORuIII)-O-III(OH2) (bpy)(2)](4+) (1). The net reaction shown below occurs by reversible, 1-electron ox idation to [(bpy)(2)(NH3)RuORu(NH3)(5)](5+) followed by irreversible 5 -electron oxidation and proton loss. At pH 12.2, cis,cis-[(bpy)(2)(NO2 )RuORu(NO2) (bpy)(2)(NO2)RuORu(NO2)(bpy)(2)](2+) is formed in 11% yiel d by a competitive pathway involving capture of an oxidized intermedia te by OH-.