Synthesis and structures of two cobalt(II) coordination networks formed from aromatic polycarboxylates and 1,4-bis(imidazole-1-ylmethyl)benzene

Two Co(II) coordination polymers, [Co(Hbtc)(bix)]n, (1) and [Co(1,4-bdc)(bix)H2O]n (2) (bix = 1,4-bis(imidazole-1-ylmethyl)benzene; H3btc = benzene-1,3,5-tricarboxylic acid; 1,4-H2bdc = benzene-1,4-dicarboxylic acid) have been synthesized under hydrothermal conditions and structurally characterized. X-ray structure analysis reveals that in polymer 1, 2D infinite grid-like frameworks are interconnected by hydrogen-bond interactions to result in a 3D supramolecular architecture, in which the three carboxylate groups of the H3btc molecule adopt three different coordination modes. In polymer 2, 1,4-bdc ligands with cobalt atoms construct 1D zigzag chains which are bridged by bix ligands to form a 3D framework.