Hydrothermal syntheses, crystal structures and luminescence properties of zinc(II) coordination polymers constructed by bifunctional 4′-(4-carboxyphenyl)-3,2′:6′,3″-terpyridine

Four polymeric frameworks, [Zn(cptpy)2(Hcptpy)2]·2H2O (1), [Zn(cptpy)Cl]n (2), [Zn4(cptpy)2(3-btc)2]n·nH2O (3) and [Zn2(cptpy)(2-btc)]n (4), (Hcptpy = 4′-(4-carboxyphenyl)-3,2′:6′,3″-terpyridine, H3(3-btc) = 1,3,5-benzenetricarboxylic acid, H3(2-btc) = 1,2,4-benzenetricarboxylic acid) have been hydrothermally synthesized and characterized by elemental analysis, IR spectroscopy and single crystal X-ray diffraction analyses. Compound 1 has a mononuclear structure, while 2 shows a one-dimensional ladder chain containing 28 member rings with (cptpy)− anions as bridges. For compounds 1 and 2, weak hydrogen bonding and intra- and/or inter-molecular π⋯π stacking interactions link the mononuclear or infinite chain structures into high-dimensional supramolecular structures. Compound 3 reveals a (4,4,4)-connected three-dimensional (3D) framework. Compound 4 is a three dimensional network structure comprised of new tetranuclear zinc clusters, exhibiting a {4·6·8}{42·6·83}{42·62·82}{43·62·85} topological structure. In addition, the thermal stabilities and photoluminescence properties of 1–4 were also studied.

Four new ZnII compounds with the 4′-(4-carboxyphenyl)-3,2′:6′,3″-terpyridine ligand were prepared and characterized. Compound 1 is a mononuclear structure, while 2 shows a ladder chain, suggesting that the pH value has a key impact on the structures. Compounds 3 and 4, with two types of 3D framework, were obtained when different secondary ligands were introduced into the system. The thermal stabilities and photoluminescence properties of 1–4 were also studied.Figure optionsDownload as PowerPoint slide