Two elongated octahedral coordination cages constructed by M4-TC4A secondary building units (M = CoII and FeII) and 2,2'-bipyridine-4,4'-dicarboxylic acids.

Two nanoscale coordination cages based on M4-TC4A (M = Co(II) and Fe(II); H4TC4A = p-tert-butylthiacalix[4]arene) and 2,2'-bipyridine-4,4'-dicarboxylic acid (H2bpdc) have been synthesized and characterized. In these isostructural structures, there are two kinds of shuttlecock-like M4-TC4A secondary building units, {M4(TC4A)(Cl)} and {M4(TC4A)(SO4)}, which have different coordination environments and are bridged by bpdc molecules into an elongated octahedron through a [6 + 8] condensation. The gas sorption and magnetic properties were studied.