Utilizing diruthenium components for the design of cyanide-linked tri- and tetranuclear organometallic complexes with multistep one-electron redox processes

Reactions between the acetate-bridged diruthenium complex Ru-2(O2CCH3)(4)Cl and the cyanide-containing organometallic complex Cp(dppe)FeCN or Cp(PPh3)(2)RuCN brought about the isolation of the cyanide-linked tetranuclear complexes [{Cp(dppe)FeCN}(2)Ru-2(O2CCH3)(4)](SbF6) (1SbF(6)) and [{Cp(PPh3)(2)RuCN}(2)Ru-2(O2CCH3)(4)](SbF6) (2SbF(6)), while the similar reactions of the ap- or Fap-bridged (ap = 2-anilinopyridinate anion, Fap = 2-(2-fluoroanilino)pyridinate anion) diruthenium complex Ru-2(ap)(4)Cl or Ru-2(Fap)(4)Cl with Cp(dppe)FeCN or Cp(PPh3)(2)RuCN gave the cyanide-linked trinuclear complexes [Cp(dppe)FeCNRu2(ap)41 (SbF6) (3SbF(6) [Cp(PPh3)(2)RuCNRu2(ap)(4)](SbF6) (4SbF(6)), [Cp(dppe)FeCNRu2(Fap)(4)](SbF6) (5SbF(6)), and [Cp(PPh3)(2)RuCNRu2(Fap)(4)](SbF6) (6SbF(6)). The structural analyses indicate that the steric effect is the predominant factor to govern the nuclelarity of the cyanide-linked "species. The steric hindrance derived from (4, 0) (for Ru-2(ap)(4)) or (3,1) (for Ru-2(Fap)(4)) orientation in the diruthenium. components is extremely unfavorable for the. formation of the tetranuclear arrays MCNRu2(ap)(4)NCM or MCNRu2(Fap)(4)NCM (M = Fe or Ru) so as to afford the trinuclear assembly MCNRu2(ap)(4) or, MCNRu2(Fap)(4) instead. The cyanide-linked complexes possess rich redox chemistry to afford two or more reversible redox processes. The complexes were characterized by elemental analysis, IR, UV-vis, P-31 NMR, and ES-MS spectroscopy, and cyclic voltammetry. The crystal structures of 2SbF(6)-5SbF(6) were determined by X-ray, crystallography.