Controlled Assembly of Dinuclear Metallacycles into a Three-Dimensional Helical Array

The new angular bridging ligand 2,4′-(1,4-phenylene)bispyridine toposelectively forms dinuclear metallacycles with Cd(NO3)2 and Zn(NO3)2. The CdII helicates associate into an unprecedented three-dimensional zeolite-like helical coordination polymer with hexagonal hydrophobic channels with a diameter of about 10 Å (see scheme). These channels, initially occupied by uncoordinated ligand molecules, can be emptied to afford a guest-free coordination polymer.