Formation of a Large Confined Spherical Space with a Small Aperture Using Flexible Hexasubstituted Sumanene

Two sumanene-based porous coordination networks were successfully prepared by the complexation of hexa­pyridyl­sumanene with Zn­(NO3)2·6H2O or Cd­(NO3)2·4H2O. X-ray single crystal analysis unambiguously revealed that the curved structure of the central sumanene skeleton of the ligand resulted in the formation of a large confined space with a small aperture size. In the Zn2+ network, the beltlike trimer units were connected to each other to form a 1D channel separated by the counteranion to afford isolated spaces. The Cd2+ network formed spherical tetramer units, which also eventually afforded a 1D channel with open windows smaller than the kinetic diameter of helium. The investigation of the structural parameters of the ligand in both networks revealed the unique feature of hexa­pyridyl­sumanene, which flexibly changed its bond length and angles depending on the structural requirements for the network formations.