Self-assembly of nanoscopic coordination cages of D(3h) symmetry.

A family of nanoscale-sized supramolecular cage compounds with a trigonal prismatic framework was prepared by means of spontaneous self-assembly from the combination of a predesigned molecular "clip" with tritopic pyridyl subunits. As confirmed by x-ray crystallography, the smallest structure of the reported series is approximately 1 x 2 nm and possesses a nitrate anion incarcerated inside its molecular cavity. The largest structure has dimensions of approximately 1 x 4 nm.