2.4.2. Interpenetrated Ladders 711 2.4.3. Unusual Motifs of Ladders 713 2.4.4. Properties of Ladderlike Chains 713 2.5. Rotaxane Polymers 714 2.5.1. 1D Polyrotaxanes 714 2.5.2. 2D Polyrotaxanes 715 2.5.3. 3D Polyrotaxanes 716 2.5.4. Hydrogen-Bonded Polyrotaxanes 716 2.6. Ribbon/Tape Polymers 717 2.7. Metal Cluster As Building Blocks for 1D CP 718 2.7.1. Metal Carboxylate Clusters 718 2.7.2. Metal Halide Clusters 719 2.7.3. Metal Chalcogenide Clusters 720 2.7.4. Polyoxometalate Clusters 721 2.7.5. Single Molecular Magnets as Building Blocks 722

One-Dimensional Coordination Polymers: Complexity and Diversity in Structures, Properties, and Applications

Hydro(solvo)thermal in situ ligand syntheses

Crystal engineering is the rational design and assembly of solid-state structures with desired properties via the manipulation of intermolecular interactions, hydrogen bonding and metal–ligand complexation in particular. The heart of crystal engineering is to control the ordering of the building blocks, be they molecular or ionic, toward a specific disposition in the solid state. The relatively weak strength of intermolecular forces with respect to chemical bonding renders the assembly of supramolecular constructs sensitive to external physical and chemical stimuli, with pH condition of the reaction mixture being arguably the most prominent and extensively observed. Using selected examples of constructing metal–organic architectures from recent literature, the influences of pH on the specific ligand forms, the generation and metal coordination of hydroxo ligands, ligand transformation promoted by pH condition changes, pH-dependent kinetics of crystallization of a number of metal–organic architectures are discussed. Current status of this particular areas of research in supramolecular chemistry and materials are assessed and personal perspectives as to toward what directions should this chemistry head are elaborated.

pH effect on the assembly of metal-organic architectures

A series of four new coordination polymers, namely, [Co(HL1)(μ-4,4′-bpy)(H2O)3]n·(4,4′-bpy)n·(H2O)2n (1), [Co1.5(L2)(μ-4,4′-bpy)1.5]n·(4,4′-bpy)0.5n (2), [Co3(L3)(HL3)(OH)(H2O)2(μ-4,4′-bpy)2]n·(H2O)2.5n (3), and [Co1.5(L4)(μ-4,4′-bpy)2(H2O)3]n·(H2O)3n (4), have been assembled from four asymmetric semirigid multicarboxylate ligands 3-(4-carboxy-phenoxy)-phthalic acid (H3L1), 3-(2-carboxy-phenoxy)-phthalic acid (H3L2), 4-(2-carboxy-phenoxy)-phthalic acid (H3L3), and 4-(4-carboxy-phenoxy)-phthalic acid (H3L4) with the help of 4,4′-bipyridine (4,4′-bpy) ligand. X-ray single crystal diffraction analysis reveals that compound 1 displays a one-dimensional (1D) zigzag chain structure constructed from 4,4′-bpy ligands and partly deprotonated L1 ligands, which further forms a three-dimensional (3D) supramolecular architecture via hydrogen bonds. Complex 2 possesses a two-dimensional (2D) layered architecture composed of continuous trinuclear Co(II) clusters. Complex 3 also shows a 2D molecular framework assembled f...

Co(II) Metal−Organic Frameworks (MOFs) Assembled from Asymmetric Semirigid Multicarboxylate Ligands: Synthesis, Crystal Structures, and Magnetic Properties

Four new Cu(II)-azido complexes of formula [CuL(N(3))] (1), [CuL(N(3))](2) (2), [Cu(7)L(2)(N(3))(12)](n) (3), and [Cu(2)L(dmen)(N(3))(3)](n) (4) (dmen = N,N-dimethylethylenediamine) have been synthesized using the same tridentate Schiff base ligand HL (2-[1-(2-dimethylaminoethylimino)ethyl]phenol, the condensation product of dmen and 2-hydroxyacetophenone). The four compounds have been characterized by X-ray structural analyses and variable-temperature magnetic susceptibility measurements. Complex 1 is mononuclear, whereas 2 is a single mu-1,1 azido-bridged dinuclear compound. The polymeric compound 3 possesses a 2D structure in which the Cu(II) ions are linked by phenoxo oxygen atoms and two different azide bridges (mu-1,1 and mu-1,1,3). The structure of complex 4 is a double helix in which two mu-1,3-azido-bridged alternating one-dimensional helical chains of CuL(N(3)) and Cu(dmen)(N(3))(2) are joined together by weak mu-1,1 azido bridges and H-bonds. The complexes interconvert in solution and can be obtained in pure form by carefully controlling the conditions. The magnetic properties of compounds 1 and 2 show the presence of very weak antiferromagnetic exchange interactions mediated by a ligand pi overlap (J = -1.77) and by an asymmetric 1,1-N(3) bridge (J = -1.97 cm(-1)), respectively. Compound 3 presents, from the magnetic point of view, a decorated chain structure with both ferro- and antiferromagnetic interactions. Compound 4 is an alternating helicoidal chain with two weak antiferromagnetic exchange interactions (J = -1.35 and -2.64 cm(-1)).

A Unique Example of Structural and Magnetic Diversity in Four Interconvertible Copper(II)―Azide Complexes with the Same Schiff Base Ligand: A Monomer, a Dimer, a Chain, and a Layer

The coordination chemistry of inorganic cobalt salt and the organic ligands H4bbh (=benzene-1,2,4,5-bihydrazide) and H3bcbh (=benzene-4-carboxylate-1,2-bihydrazide) generated through the in situ hydrothermal acylate reaction of H4bta (=benzene-1,2,4,5-tetracarboxylic acid) and H3btc (=benzene-1,2,4-tricarboxylic acid) with hydrazine hydrate, respectively, has been investigated. Three new coordination polymers were prepared and fully characterized by infrared spectroscopy, elemental analysis, and single-crystal X-ray diffraction. The compound [Co(μ3-H2bbh)(phen)]n (1) (triclinic space group P1 with a = 9.762(4) A, b = 10.169(4) A, c = 11.143(4) A, α = 80.96(3)°, β = 64.49(3)°, γ = 71.88(3)°, Z = 2) was synthesized from the reaction of CoCl2·6H2O, H4bta (=benzene-1,2,4,5-tetracarboxylic acid), N2H4·H2O, phen (=1,10-phenanthroline) and H2O, and consists of one-dimensional double-chains. [Co(μ4-H2bbh)(H2O)2]n (2) (monoclinic space group P2(1)/c with a = 6.8687(5) A, b = 7.5943(6) A, c = 10.0401(6) A, β = 95....

A new route for preparing coordination polymers from hydrothermal reactions involving in situ ligand synthesis.

1-D water chains constructed by dimer water clusters and edge-sharing cyclic pentamer have been observed in the compound [Co(C4H4O6)(2,2‘-bipy)·5H2O] (1), in which the water chains join the 1-D coo...

Xiao-Yan Chen

Papers

A new route for preparing coordination polymers from hydrothermal reactions involving in situ ligand synthesis.

Novel self-assembled chain of water molecules in a metal-organic framework structure of Co(II) with tartrate acid.