Poly[[[μ-1,4-bis-(pyridin-4-ylcarbon-yl)piperazine-κ:'][μ-2-(2-carboxyl-atoeth-1-en-1-yl)benzoato-κ:]zinc(II)] 2.5 hydrate]: a tri-periodic coordination polymer with a dimer-based six-connected pcu topology.

The title compound, {[Zn(CHO)(CHNO]·2.5HO}, contains five-coordinate Zn ions inter-mediate between square-pyramidal and trigonal-bipyramidal coordination environments. The Zn ions are connected by 2-carb-oxy-cinnamate (cca) ligands and ,'-bis-(pyridine-4-carboxamido)-piperazine (4-pcap) ligands to construct a non-inter-penetrated, tri-periodic coordination polymer with embedded [Zn(OCO)] dimeric units. Treating these as six-connected nodes reveals an overall (46) topology. One of the 4-pcap piperazinyl rings is disordered equally over two sets of crystallographic positions.