Molecular quadrangles: Cyanide bridged tetranuclear complexes with Fe, Ni, and Zn constituents

Using cis-(bpy)(2)FeX2 building blocks the stepwise formation of molecular quadrangles with Fe2M2(mu-CN)(4) frameworks was achieved. Intermediates were dinuclear complexes with Fe-CN-M units (M = Ni, Cu) and trinuclear complexes with Zn(NC-Fe)(2) and Fe(CN-M)(2) units (M = Ni, Cu). Spectroscopic and electrochemical data were obtained. The structures of the trinuclear Fe(CN-CU)(2) complex and the tetranuclear Fe-4(mu-CN)(4) complex were determined.