Stepwise Assembly of [(C5H5)4(C5Me5)4Co4Rh4(CN)12]4+, an “Organometallic Box”

A volume of 132 Å3 is enclosed by the title compound 1, which thus offers plenty of room for potential guest molecules. The synthesis from 2 [{Cp*RhCl2}2] and 4 [CpCo(CN)3]− begins with the construction of a “molecular square” whose corners are alternately occupied by Co and Rh centers. Two squares react with one another to give a “molecular box” without cleavage of any M–C bonds. Cp=C5H5, Cp*=C5Me5.