Lai-Ping Zhang

A series of 2D and 3D metal–organic frameworks based on different polycarboxylate anions and a flexible 2,2′-bis(1H-imidazolyl)ether ligand

Eight new coordination polymers, namely [Ni(L1)(BIE)] (1), [Cu(L1)(BIE)] (2), [Cu(L2)(BIE)] (3), [Co(L3)(BIE)] (4), [Cu(L4)0.5(BIE)] (5), [Co2(L4)(BIE)2]·H2O (6), [Cu5(L5)4(μ3-O)2(BIE)2(H2O)2] (7) and [Cu3(L6)2(BIE)2(H2O)3] (8), where L1 = p-phthalate, L2 = o-phthalate, L3 = oxalate, L4 = 1,2,4,5-benzenetetracarboxylate, L5 = m-phthalate, L6 = 1,3,5-benzenetricarboxylate and BIE = 2,2′-bis(1H-imidazolyl)ether, were successfully synthesized under hydrothermal conditions. Polymers1–4 display 2D layer structures. 1, 2 and 3 hold the similar 4-connected 44-sql nets, while 4 exhibits a 3-connected 63-hcb net. 5 possesses an unusual 4-connected Kagome net with two kinds of connected nodes. 6 shows a rare 3,4-connected (83)2(85·10) topology with 3-connected nodes and square-planar 4-connected nodes. 7 exhibits an α-Po topology based on pentanuclear Cu(II) cluster. 8 is a unique self-penetrating 2D network with 3,4-connected (6·72)(6·7·8)(62·7·82·9) topology. The structural differences of 1–8 suggest the importance of polycarboxylate ligands and central metals in the network construction of the coordination polymers.

Four novel topological frameworks based on 4,4′-(hexafluoroisopropylidene)diphthalic acid and 1,1′-(1,4-butanediyl)bis(imidazole) ligand

Four new coordination polymers, constructed from 4,4′-(hexafluoroisopropylidene)diphthalic acid (H4L) and 1,1′-(1,4-butanediyl)bis(imidazole) (biim-4) ligand, have been synthesized: [Cd(HL)(Hbiim-4)(biim-4)0.5(H2O)]·2H2O (1), [Cd2(L)(biim-4)0.5(H2O)2]·0.5H2O (2), [Mn2(L)(biim-4)0.5(H2O)2]·0.5H2O (3), and [Zn2(L)(biim-4)1.5]·(CH3CH2OH) (4), where H4L = 4,4′-(hexafluoroisopropylidene)diphthalic acid, and biim-4 = 1,1′-(1,4-butanediyl)bis(imidazole). Compound 1 displays a 1D chain structure, which is extended by intermolecular hydrogen-bonding interactions to give a novel trinodal (4,5)-connected (4·64·8)(42·63·8)(43·64·83) topology. Compounds 2 and 3 are nearly isostructural with the same uncommon (5,6)-connected frameworks. Compound 4 shows an unprecedented self-penetrating (4,5)-connected net with Schlafli symbol of (42·6·72·8)(62·72·82)(42·63·73·82). The structural and topological differences of these four compounds indicate that the pH values and the central metals have significant effects on producing novel structures and topologies of the coordination complexes. The thermogravimetric and photoluminescent properties were also investigated for the compounds.

Four silver-containing coordination polymers based on bis(imidazole) ligands

Four coordination polymers, [Ag(L1)](m-Hbdc) (1), [Ag(L1)]2(p-bdc) · 8H2O (2), [Ag(Hbtc)(L1)][Ag(L1)] · 2H2O (3) and [Ag2(L2)2](OH-bdc)2 · 4H2O (4), where L1 = 1,1′-(1,4-butanediyl)bis(imidazole), L2 = 1,2-bis(imidazol-1-ylmethyl)benzene, m-H2bdc = 1,3-benzenedicarboxylic acid, p-H2bdc = 1,4-benzenedicarboxylic acid, H3btc = 1,3,5-benzenetricarboxylic acid, and OH–H2bdc = 5-hydroxisophthalic acid, were synthesized under hydrothermal conditions. Compound 1 contains a–Ag-L1–Ag-L1–chain and a hydrogen-bonding interaction induced–(m-Hbdc)-(m-Hbdc)–chain. Compound 2 consists of two independent–Ag-L1–Ag-L1–chains. P-bdc anions are not coordinated. Hydrogen bonds form a 3D supramolecular structure. A novel (H2O)16 cluster is formed by lattice water molecules in 2. Compound 3 contains a–Ag-L1–Ag-L1–and a–Ag(Hbtc)-L1–Ag(Hbtc)-L1–chain. The packing diagram shows a 2D criss-cross supramolecular structure, with π ··· π and C–H ··· π interactions stabilizing the framework. Compound 4 contains a [Ag2(L2)2]2+ dimer with hydrogen-bonding, π ··· π, and Ag ··· O interactions forming a 3D supramolecular framework. The luminescent properties for these compounds in the solid state are discussed.

catena-Poly[[[bis­(4-amino­benzoato-κO)copper(II)]-μ-1,1′-(pentane-1,5-di­yl)diimidazole] trihydrate]

In the title compound, {[Cu(C7H6NO2)2(C11H16N4)]·3H2O}n, each CuII atom is coordinated by two O atoms from two 4-aminobenzoate anions, and two N atoms from two different 1,1′-(pentane-1,5-diyl)diimidazole (biim-5) ligands, to furnish a distorted square-planar geometry. The biim-5 ligand coordinates to two copper(II) cations, acting as a bridging ligand; as a result the copper(II) cations are connected to form an infinite chain structure. The polymeric chains are linked through a variety of hydrogen bonds to form a three-dimensional structure.

(5,6:19,20-Dibenzo-1,4,11,14-tetra­oxa-8,17-diaza­cyclo­eicosane-κ4N8,O11,O14,N17)dinitrato-κ4O,O′-cadmium(II)

In the title compound, [Cd(NO3)2(C22H30N2O4)], the CdII atom is eight-coordinated by two amine N atoms and two O atoms from the 5,6:19,20-dibenzo-1,4,11,14-tetraoxa-8,17-diazacycloeicosane ligand and four O atoms from two nitrate groups. The coordination geometry about Cd is antiprismatic. One nitro O atom is disordered equally over two positions.

1,1′-(4-Oxoheptane-1,7-di­yl)bis­(2-methyl-1H-benzimidazole) penta­hydrate

The title compound, C23H26N4O·5H2O, has noncrystallographic twofold rotation symmetry in the solid state. It crystallizes with five solvent water molecules in the asymmetric unit. Four of these water molecules are connected with each other via hydrogen-bonding interactions to form two types of centrosymmetric hexameric (H2O)6 rings. Via edge sharing of the hexamers, the water clusters thus build infinite chains that stretch parallel to the a axis. The fifth water molecule provides an additional connection between the two hexameric (H2O)6 units via hydrogen bonds to both rings. The water molecules in the channels along the a axis are also bonded via O—H⋯N hydrogen bonds to the organic units, and face-to-face π–π interactions [with centroid-to-centroid distances of 3.656 (1) Å and average face-to-face distances of 3.431 (5) Å] between the aromatic rings of adjacent molecules complete the intermolecular interactions in this structure.

(Benzene-1,3-dicarboxyl­ato-κ2O1,O1′)(1,12,15,26-tetra­aza-5,8,19,22-tetra­oxa-3,4:9,10:17,18:23,24-tetra­benzocyclo­octa­cosane-κ4N1,N12,N15,N26)cadmium(II) benzene-1,3-dicarboxylic acid solvate

In the title compound, [Cd(C8H4O4)(C36H44N4O4)]·C8H6O4, the CdII atom is six-coordinated by four N atoms from the macrocyclic ligand and two O atoms from a benzene-1,3-dicarboxylate ligand. The complex molecules are linked by N—H⋯O hydrogen bonds, forming a one-dimensional chain structure along the b axis. The chains are further connected through N—H⋯O and O—H⋯O hydrogen bonds between the complex molecule and an uncoordinated benzene-1,3-dicarboxylic acid molecule, resulting in a two-dimensional supramolecular network.