Supramolecular Self-Assembly of Zigzag Coordination Polymer Chains: A Fascinating Three-Dimensional Polycatenated Network Featuring an Uneven “Density of Catenations” and a Three-Dimensional Porous Network

Reaction of ZnII or CdII nitrate with mixed ligands biphenylethene-4,4‘-dicarboxylate (bpea) and 1,10-phenanthroline (phen) under the same conditions affords two zigzag polymer chains [Zn(bpea)(phen)] (1) and [Cd(bpea)(phen)(H2O)]·H2O (2). The zigzag chains in 1 propagate in two non-coplanar directions (rotated by 73°) that are assembled by supramolecular forces into an intriguing three-dimensional (3D) polycatenated network featuring an uneven “density of catenation” for an individual interlocked component. In 2, however, all the zigzag chains extend in the same direction and are linked to one another by supramolecular forces into a 3D porous network featuring rectangular channels. Thermal stability of the two compounds also was studied in this paper.