Syntheses, crystal structures, and photoluminescence of two new coordination polymers derived from dicarboxylate and N-donor ligands

Two metal-organic coordination polymers, [Co(tda)(ip)(H2O)2] n (1) and [Mn(tda)(ip)(H2O)] n (2) [H2tda = thiophene-2,5-dicarboxylic acid, ip = 1H-imidazo[4,5-f][1,10]-phenanthroline], have been synthesized and characterized by elemental analyses, IR, PXRD, and X-ray diffraction. Single-crystal X-ray analyses reveal that 2,5-tda is a bridging ligand, exhibiting two coordination modes to link metal ions: μ1-η1 : η0/μ1-η1 : η0 and μ2-η1 : η1/μ1-η1 : η0. Compound 1 demonstrates a 1-D structure in which Co2+ centers are connected via tda anions into 1-D chains; the chains are further connected via hydrogen-bonding and π ··· π interactions. Compound 2 displays a 2-D structure in which tda connects two Mn ions forming a dinuclear molecule. In 2 the 3-D supramolecular structure arrays through hydrogen-bonding and π ··· π interactions. In addition, photoluminescence for 1 and 2 is also investigated in the solid state at room temperature.