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

• Divalent metal coordination polymers with pyromellitate ligands.
• Bis(4-pyridylformyl)piperazine (4-bpfp) coligands.
• Uncommon 3-D binodal fsc network or 1-D chain topologies.
• Metal or pH level determines topology choice.

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.

Hydrothermal synthesis has yielded four divalent metal coordination polymers containing both bis(4-pyridylformyl)piperazine (4-bpfp) and pyromellitate (pyro) ligands. {[Cd(pyroH2)(4-bpfp)]·2H2O}n has an uncommon 3-D fsc network, while {[Zn2(pyro)(4-bpfp)(H2O)8]·4H2O}n shows aggregated 1-D coordination polymer chains.Figure optionsDownload as PowerPoint slide