Divalent metal pyromellitate coordination polymers containing bis(4-pyridylformyl)piperazine: Selection between simple chain and rare fsc network topologies

Hydrothermal synthesis has yielded four divalent metal coordination polymers containing both bis(4-pyridylformyl)piperazine (4-bpfp) and pyromellitate (pyro, 1,2,4,5-benzenetetracarboxylate) ligands, which were structurally characterized by single-crystal X-ray diffraction. Various topologies were obtained depending on specific metal used and level of base in the reaction mixture. {[Cd(pyroH2)(4-bpfp)]·2H2O}n (1) displays an uncommon 3-D binodal fsc network, while {[Zn2(pyro)(4-bpfp)(H2O)8]·4H2O}n (2) and {[Co2(pyro)(4-bpfp)(H2O)8]·4H2O}n (3) manifest aggregated 1-D coordination polymer chains. A decrease in amount of added base from that used in the preparation of 3 resulted in the generation of {[Co(pyroH2)(4-bpfp)]·2H2O}n (4), which has the same 3-D fsc topology as 1. The closed shell complexes 1 and 2 emit blue-violet and blue light, respectively, upon ultraviolet irradiation. Dehydration and decomposition behavior of these four new materials is also presented.