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Five novel Zn(II)/Cd(II) coordination polymers (CPs) based on the V-shaped ligand 1H-3,5-bisIJpyrazinyl)- 1,2,4-triazole (Hbpt) and different polycarboxylates, {[Cd(bpt)(H2O)]·ClO4·H2O} (1), {[Cd4(bpt)2(suc)2.5(OH)]· 3H2O} (2), {[Cd4(bpt)3)1,3-bdc)2.5]·4H2O} (3), {[Cd9(bpt)6(1,4-bdc)6(H2O)2]·4H2O} (4) and {[Zn2(bpt)(H3bhc)- (H2O)6]·H2O} (5) (H2suc = succinic acid, 1,3-H2bdc = isophthalic acid, 1,4-H2bdc = terephthalic acid, H6bhc = benzene-1,2,3,4,5,6-hexacarboxylic acid), have been successfully synthesized. Their structures have been characterized using single-crystal X-ray crystallography, powder X-ray diffraction (PXRD) analyses, elemental analyses, IR spectroscopy, and thermogravimetric analyses (TGA). Complex 1 bears a two-dimensional (2D) layered (3,3) network, which is further extended into the resulting three-dimensional (3D) supramolecular architecture via π...π stacking interactions between the terminal pyrazine groups of bpt- ligands. In 2, Cd(II) ions and bpt- ligands construct a 2D Cd-bpt layer and two 1D zigzag chains, which are further connected by suc2- ligands to form a 2D + 1D → 3D (4,5)-connected framework. Complex 3 contains two kinds of grids, and their alternating arrangement gives a final complicated 3,4,5-connected network with a stoichiometry of (3-c)6(4-c)9(5-c)2. In 4, the bpt- ligands act as tetradentate ones to connect neighbouring Cd(II) ions into an infinite 1D Cd-bpt chain. The completely deprotonated 1,4-bdc2- ligands further link the adjacent Cd-bpt chains to generate a novel 3,4,6-connected 3D topological network with (3-c)2(4-c)14(6-c). Complex 5 displays an infinite 1D coordination chain. There are strong π...π stacking interactions between adjacent chains in 5 with a centroid-centroid distance of 3.860 Å and 3.862 Å, resulting in a 3D supramolecular structure. The results show that Hbpt can act as a versatile building block for the construction of various coordination polymers. Moreover, the fluorescence properties of 1-5 in the solid state have also been investigated. [ABSTRACT FROM AUTHOR]

A series of luminescent lanthanide coordination complexes, [Eu2(hqc)6(H2O)4]·8H2O (1), [Ln2(hqc)6(H2O)2(DMF)2]·2H2O (Ln = Eu (2), Dy (3), Ho (4)), and [Ln2(hqc)6(H2O)4]·2H2O·2DMF (Ln = Ce (5), La (6), Pr (7); Hhqc =2-hydroxyquinoline-4-carboxylic acid), have been synthesized via evaporative crystallization and then characterized by single-crystal X-ray diffraction. Complexes 1−7are nine-coordinated lanthanide(III) complexes with distorted tricapped trigonal prism geometry around each metal center. The dinuclear units in 1−7form the two-dimensional square networks and further extend to three-dimensional supramolecular frameworks through the π−π stacking and strong hydrogen bonding interactions. The optical properties of complexes 1−7in both the solid state and solution state were investigated in detail at room temperature and 10 K. The results show that the Eu3+ions in 1and 2could be highly sensitized by the hqc−ligands and thus emit intense red luminescence with long lifetimes, while complexes 3and 5−7exhibit the characteristic blue luminescence. Furthermore, X-ray diffraction and thermogravimetric analysis of 1−7are also studied, which demonstrate their high purities and good thermal stabilities. [ABSTRACT FROM AUTHOR]

Two MMOFs with double-walled tubular structures have been presented: [In(aip)(µ2-OH)]n·3nH2O (1) and [In2(Hsip)2(µ2-OH)2(H2O)]n·2nH2O (2) (H2aip = 5-aminoisophthalic acid, NaH2sip = 5-sulfoisophthalic acid monosodium salt), which both consisted of alternatively arranged left- and right-handed nested coaxial bi-strand helices interconnected by the ligands. The channels in complex 2are functionalized by the unligated sulfonate anion groups as Lewis base functional groups which also act as windows of the channels. [ABSTRACT FROM AUTHOR]

A series of novel two-dimensional (2D) lanthanide coordination polymers with 4-hydroxyquinoline-2-carboxylate (H2hqc) ligands, [Ln(Hhqc)3 (H2O)]n.3nH2O (Ln=Eu (1), Tb (2), Sm (3), Nd (4), and Gd (5)) and [Ln(Hhqc)(ox)(H2O)2]n (Ln=Eu (6), Tb (7), Sm (8), Tm (9), Dy (10), Nd (11), Yb (12), and Gd (13); H2Ox=oxalic acid), have been synthesized under hydrothermal conditions. Complexes 1--5 are isomorphous, which can be described as a two-dimensional (2D) hxl/Shubnikov network based on Ln2(C02)4 paddle-wheel units, and the isomorphous complexes 6--13 feature a 2D decker layer architecture constructed by Ln-ox infinite chains cross-linked alternatively by bridging Hhqc- ligands. The room-temperature photoluminescence spectra of complexes EuIII (l and 6), TbIII (2 and 7), and SmIII (3 and 8) exhibit strong characteristic emissions in the visible region, whereas NdIII (4 and 11) and YbIII (12) complexes display NIR luminescence upon irradiation at the ligand band. Moreover, the triplet state of H2hqc matches well with the emission level of EuIII, TbIII, and SmIII ions, which allows the preparation of new optical materials with enhanced luminescence properties. [ABSTRACT FROM AUTHOR]