Two temperature-dependent Cd(II)-based coordination polymers with mixed adenine nucleobase and benzene-1,4-dicarboxylic acid: synthesis, structures and fluorescence properties

Two Hade-based Cd(II) polymers, [Cd(Hade)(tp)](n)(1) and {[Cd-6(Hade)(6)(tp)(6)]center dot 9H(2)O}(n)(2) (Hade = adenine, H(2)tp = benzene-1,4-dicarboxylic acid), were obtained from the same reaction system at different temperatures which have been characterized by single-crystal X-ray diffraction, elemental analysis, FT-IR spectroscopy, thermogravimetric analysis, and luminescence spectroscopy. Significantly resulting from the synergistic coordination of nucleobase and bicarboxylate groups, they are a 3-D pillared-layer structure for1and a 2-D grid structure where the dicadmium paddle-wheel motifs are double bridged by benzene-1,4-dicarboxylate anions for2.The supramolecular architecture of2is essentially knitted by hydrogen bonding interactions produced by the exocyclic amino/endocyclic imino groups of the nucleobase and the carboxylate groups of the co-ligand to favorably stabilize the high-dimensional supramolecular architectures. At room temperature,1and2exhibit intense luminescent emissions originating from a Hade-based intraligand and/or photoinduced charge transfer upon adenine binding mode.