Self-assembly of Two Cobalt(II) Coordination Polymers with 1,2,4,5-benzenetetracarboxylate and 1,3-bi(4-pyridyl)propane Ligands.

Two cobalt(II) coordination polymers [Co(H2O)2(H2btec) (bpp)2]n (1) and {[Co2(H2O)4(bpp)3(btec)]· 4H2O}n (2) were synthesized under ambient conditions with 1,2,4,5-benzenetetracarboxylic acid (btec) and 1,3-bi(4-pyridyl)propane (bpp) as mixed ligands. Complex 1 is characteristic of one-dimensional chains bridged by H2btec ligands, the terminal bpp ligands complete the coordination sphere of the cobalt atoms and are further hydrogen-bonded to neighboring chains via O-H· · · N bonds. Complex 2 features a three-dimensional framework constructed by btec4- and co-bridging bpp ligands. The cobalt ions in 2 are joined together by the btec ligands to generate Co4 squares which link to each other in an corner-sharing mode to form a 3D topology. The terminal bpp ligands filling in the networks further contribute to the stability of the crystal structure. [ABSTRACT FROM AUTHOR]