The three crystallographic structures consist of nearly identical 3D coordination frameworks. These frameworks consist of two types of continuous helical 1D hexagonal and trigonal channels with diameters of 8.8 Å and 12.5 Å, respectively. The inner structures of these two different channels have the same handedness and pitches of 1.8 nm (threefold) and 3.6 nm (sixfold) and run parallel to the crystallographic c-axis. The a and b axes pass through two tips of the flower (Figure ). The metal centers are arranged in planes perpendicular to the orientation of the channels; the distance between these planes is 1.8 nm. The metal centers have an octahedral coordination geometry. Four AdDB molecules are each coordinated with one pyridine group to one metal center in equatorial positions.