Systematic assembly of the double molecular boxes: [Cs subset [CpCo(CN)(3)](4)[Cp*Ru](3)] as a tridentate ligand.

Cubic cage compounds composed of Co-CN-Ru linkages have been prepared which illustrate the following features: (i) new motifs for alkali metal ion complexation (i.e., cationic receptors for cations), (ii) a new family of triaza-metalloligands, and (iii) a double box-like cage. The cages are synthesized by the condensation of [CpCo(CN)(3)](-) and [Cp*Ru(NCMe)(3)](+) (cyclopentadienyl, Cp; pentamethylcyclopentadienyl, Cp*) the presence of Cs(+). The species [Cs subset[[CpCo(CN)(3)](4)[Cp*Ru](4)](+) and [Cs subset[[CpCo(CN)(3)](4)[Cp*Ru](3)[Cp*Rh]](2+) illustrate the box-completion reaction Cs subset Co(4)Ru(3) + M (M = Cp*Rh(2+), Cp*Ru(+)). With the naked ion precursors [Na(NCMe)(6)](+) and [Fe(NCMe)(6)](2+), the box-completion reactions afforded [Na[Cs subset[CpCo(CN)(3)](4)[Cp*Ru](3)]](2)](+) and [Fe[Cs subset [CpCo(CN)(3)](4)[Cp*Ru](3)]](2)](2+). These cages provide the first examples, to our knowledge, of the double-box motif.