Two Elongated Octahedral Coordination Cages Constructed by M₄‑TC4A Secondary Building Units (M = Co^II and Fe^II) and 2,2′-Bipyridine-4,4′-dicarboxylic Acids

Two nanoscale coordination cages based on M4-TC4A (M = CoII and FeII; 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.