Coordination polymers of flexible tetracarboxylic acids with metal ions. I. Synthesis of CH2- and (CH2)2-spaced bis(oxy)isophthalic acid ligands, and structural characterization of their polymeric adducts with lanthanoid ions

We report herein on the synthesis and structure of new tetracarboxylic ligands, 5,5'-methylene-bis(oxy)diisophthalic acid and 5,5'-(ethane-1,2-diyl)-bis(oxy) diisophthalic acid, bearing flexible spacers between the two isophthalic acid fragments, as well as of the coordination polymers of these two ligands with various lanthanoid metal ions. The formed compounds were characterized by X-ray crystallography, IR spectroscopy and thermal analysis. The nine hybrid organic-inorganic supramolecular assemblies reveal polymeric architectures of either two-dimensional or three-dimensional connectivity.