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Three novel structural diversiform lead(II) complexes, formulated as [Pb(HDBB)(dppz)] (1), [Pb(HDBB)(H2O)]·H2O(2), [Pb4Na(DBB)3(o-phen)3](3), have been synthesized under hydrothermal conditions based on 4-(3,5-dicarboxylatobenzyloxy) benzoic acid (H3DBB) and two N-donor ligands: dipyrido (3,2-a:2′,3′-c) phenazine (dppz) and 1,10-phenanthroline (o-phen). Structural analyses reveal complex 1 possesses 1D double-helical ladder-like chain sharing a common axis, and then the π···π interactions between adjacent dppz ligands give rise to supramolecular architecture. 2 features 2D (4,4) network based on 1D double-stranded slight helixes chains and the bridging of DBB ligands. For 3, a 3D framework arises from a hexagonal unit with the trinuclear central groups. The structural diversity from 1D to 3D of these complexes might be attributed to the coordination of auxiliary ligands. Solid-state fluorescence properties for these crystalline materials are also presented.

Three novel coordination polymers, namely, [Cd(2-Hstp)(1,4-bbi)(H 2 O) 2 ]·3H 2 O ( 1 ), [Cd 1.5 (2-stp)(1,4-bbi)(H 2 O) 2 ]·H 2 O ( 2 ) and [Zn 2 (2-stp)( μ 2 -OH)(1,4-bbi) 1.5 (H 2 O)]·6H 2 O ( 3 ) (2-H 3 stp is equal to 2-sulfoterephthalate and 1,4-bisbenzimidazole is equal to 1,4-bbi), have been synthesized by hydrothermal reaction. The structural analyses show that 1 and 2 possess different structural features despite the same raw materials, which are 1D chain structure featuring 6-member-water H-bonds cluster and 3D bbi-pillared wavy-like layer framework, respectively. As changing the metal ion to zinc ion, 3 exhibits 3D stp-pillared layer architecture, which discovers the effect of the central metal ions on the formation of metal–organic frameworks. The fluorescence studies show that the emissions of the coordination polymers are attributed to the ligand π–π * transition, which means they could be potential fluorescence materials.

A novel Eu-MOF sensor, named as [Eu5(DBA)3]n (1), has been prepared based on 3,5-di(2′,4′-dicarboxylphenyl) benozoic acid (H5DBA) and europium nitrate under solvothermal condition. Structural analysis shows that the binuclear and polynuclear inorganic building untis to form stable microporous structure based on the wholly deprotonated DBA ligands. The microporous structure of 1 has been verified by the gas adsorption experiment of N2. Fluorescence studies show that Eu-MOF can detect acetone molecules, Cu2+ ion and Cr2O72− anion with high sensitivity and selectivity, and can also be used for electrochemical detection of exposed 2,4,6-trinitrophenol (TNP) in water. The high selective and sensitive detection ability of complex 1 might make it a potential multifunctional sensor in the future.

Hydrothermal reactions of manganese (II)/cadmium(II) salts with 1,2,4-trimellitic acid (H3tma) and 2,2′:6′,2-terpyridine (tpy) result in two novel complexes formulated with [M(Htma)(tpy)]·H2O (M = Mn(1) and Cd(2)). X-ray diffraction structural analyses of two complexes reveal they are isomorphic except for the different center metal ions and crystallize in the monoclinic crystal system of P(2)/n space group. The metal ion lies in a six-coordinated distorted octahedral environment coordinated with three Htma2− anions and one tpy ligand. There is an infinite two-dimensional rhombic network based on the metallic dimmers and Htma2− anions with the tpy ligands in void. Furthermore, the tpy ligands from the adjacent network weakly interact each other by π⋯π packing interactions into 3D supramolecular structure. The fluorescence properties could be assigned to the π – π* transition of organic ligands.

Two novel lanthanide coordination polymers, {[Ln(stp)(bipy)(H2O)]·(H2O)}n [Ln = Eu (1) and Dy (2)], were synthesized by hydrothermal reactions of 2-sulfoterephthalate (stp) and 4,4′-bipyridine (bipy) ligands with europium/dysprosium(III) salts. Structural analyses show that both complexes 1 and 2 are isomorphic and crystallize in the monoclinic crystal system with space group P21/n. Complex 1 exhibits a two-dimensional grid-like structure from europium(III) ions bridged by the carboxyl and sulfonate groups of stp ligands. Notably, the stretching 4,4′-bipyridine ligands besides the 2D grid-like layers form π···π interactions and interpenetrate into the empty voids of another adjacent layer into a twofold interpenetrated structure. Fluorescence analysis show that the emission of two complexes exhibit the characteristic peaks of lanthanide ions.