Construction of monomers and chains assembled by 3d/4f metals and 4′-(4-carboxyphenyl)-2,2′:6′,2″-terpyridine

A series of transition metal and lanthanide complexes of 4′-(4-carboxyphenyl)-2,2′:6′,2″-terpyridine (HL, 1), namely [M(L)2]·5H2O (M=Ni, 2; Co, 3), [Zn(L)2]n·0.5nH2O (4) and [Ln(L)3]n (Ln=Nd, 5; Gd, 6; Er, 7) were hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction. Isomorphic compounds 2 and 3 are mononuclear molecules with two ligand chelating to the metal centers via tridentate terpyridyl, while compound 4 adopts 1D chain-like structure, in which five-coordinate zinc centers are surrounded by three ligands. Compounds 5–7 also display 1D chain-like structure, but the nine-coordinate lanthanide centers bonded by four ligands. Luminescent property indicates that compound 4 exhibits photoluminescence in the solid state at room temperature.