Guo-Wang Diao

Temperature and auxiliary ligand-controlled supramolecular assembly in a series of Zn(II)-organic frameworks: syntheses, structures and properties

Two temperature-dependent structures of 2D and 3D Zn(II)-organic frameworks (ZOFs) with a new 5-substituted benzene-1, 3-dicarboxylic ligand, 5-iodoisophthalic acid (H2IIP), and an auxiliary flexible ligand, 1,4-bis(1,2,4-triazol-1-yl)butane (btb), with different motifs, have been investigated. Results show that when the reaction was carried out at room temperature, a undulating 2D (4,4)-network, {[Zn(IIP)(btb)]·4H2O}n (1), which further extends into a novel “soft” 3D supramolecular microporous framework with two kinds of 1D nanochannels supported by face to face π⋯π stacking interactions and C–I⋯I halogen bonds, was generated. Under hydrothermal condition at 170 °C, however, a two-fold interpenetrated 3D framework with α-Po network topology, [Zn(IIP)(btb)]n (2), would be obtained. Interestingly, both the right- and left-handed 21 helical water chains lie in one kind of the nanochannels in 1. When the auxiliary ligand was replaced by a less flexible one with a shorter spacer length, 1,3-bis(1,2,4-triazol-1-yl)propane (btp), a novel temperature-independent single-walled discrete coordination tube, {[Zn(IIP)(btp)]·2H2O}n (3), was obtained at the same two temperatures. Inside the tube is found the 21 helical water chain. Interestingly, the reversible desorption/adsorption behavior to water is significantly observed in the frameworks 1 and 3. The framework 1 falls within the category of “recoverable collapsing” and “guest-induced re-formation” frameworks. The result shows their potential application as late-model water absorbents in the field of adsorption materials. Remarkably, the first discrete single-walled Zn(II) coordination tube 3 shows high framework stability and exhibits reversible desorption/adsorption to some small guest organic molecules (methanol, ethanol and isopropanol). Furthermore, these compounds exhibit blue fluorescence in the solid state.

Effect of N-donor auxiliary ligands on the engineering of crystalline architectures of a series of lead(II) complexes with 5-amino-2,4,6-triiodoisophthalic acid

The aqueous medium reactions of lead(II) nitrate with H2ATIBDC as a main ligand and bipy or biim as an auxiliary ligand lead to the two fascinating coordination polymers: [Pb(ATIBDC)(bipy)(H2O)]·3H2O (1) and [Pb(ATIBDC)(biim)]·H2O (2) [bipy = 2,2′-bipyridine, biim = 2,2′-biimidazole, and H2ATIBDC = 5-amino-2,4,6-triiodoisophthalic acid]. The interesting chiral three-dimensional (3D) network [Pb(ATIBDC)] (3) is obtained in the absence of any auxiliary ligands. Complex 1 is a one-dimensional (1D) helical chain, which further arrays into a 3D supramolecular metal–organic framework (MOF) with a 1D channel through the hydrogen-bonding and strong offset π⋯π stacking interactions. Furthermore, a 1D hydrogen-bonded helical water chain was found in 1. Interestingly, complex 1 exhibits reversible adsorption/desorption to water molecules. Framework 1 falls within the category of “recoverable collapsing” and “guest-induced re-formation” frameworks. Complex 2 features a fascinating 3D MOF. It displays a novel four-connected 4668-SOD (sodalite) zeotype network structure with 1D nanotubular channels. Complex 3 crystallizes in the chiral space group P31 and possesses a 3D honeycomb-like structure built up from a 1D Pb(II)-carboxylate-bridged helical chain with a 31 helix and ATIBDC2− ligand. The coordination modes of the ATIBDC2− ligand and crystalline architectures of the complexes are greatly dependent on the auxiliary ligands. The thermal stability and solid state fluorescent properties have been studied. Adsorption/desorption properties reveal that 2 may be used as an adsorbent material for some guest molecules. The study broadens the still very limited use of H2ATIBDC as a spacer and lead(II) ion for crystal engineering of MOFs with channels and cavities. These compounds represent the first examples of lead(II) complexes with H2ATIBDC.

(5-Amino­isophthalato-κN)triaqua­(1,10-phenanthroline-κ2 N,N′)cobalt(II) trihydrate

The NiII atom in the title compound, [Ni(C8H5NO4)(C12H8N2)(H2O)3]·3H2O, is six-coordinated in an NiN3O3 octahedral geometry. The triply water-coordinated NiII atom is chelated by the phenantroline ligand and is additionally coordinated by the amino group of the 5-aminoisophtalate anion. The anion, the coordinated and the uncoordinated water molecules interact through an extensive O—H⋯O and N—H⋯O hydrogen-bonding network, generating a three-dimensional cage-like network.

4-(4-Pyrid-yl)pyridinium 3-amino-5-carb-oxy-2,4,6-triiodo-benzoate-5-amino-2,4,6-triiodo-isophthalic acid (1/1).

In the title ammonium carboxylate–carboxylic acid co-cystal, C10H9N2 +·C8H3I3NO4 −.C8H4I3NO4, the carboxylate anion and carboxylic acid molecule are linked by O—H⋯O and N—H⋯O hydrogen bonds to form a chain running along the c axis of the monoclinic unit cell. The chains are linked by pyridinum and pyridine N—H⋯O hydrogen bonds, generating a layer motif. O—H⋯N and O—H⋯O hydrogen bonds are also observed.

Polymorphism and solvates of 1-acetyl-3-(phenyl)-5-(1-pyrenyl)pyrazoline: the structures, thermal and optical-physical properties

Single crystals of the β polymorph, formic acid and propanoic acid solvates of the title compound (abbreviation APPP) have been obtained. Single-crystal X-ray analysis revealed that the APPP molecules in the β polymorph construct the homochiral helical chains and the pyrene fluorophores adopt a monomer arrangement. Analogous structures were also found in the two solvates, while a small π-overlap exists between the pyrene fluorophores. Moreover, apart from the acetic acid solvate (form I) in a previous report, a new crystalline form (form II) was discovered through a rapid crystallization method and confirmed by PXRD patterns. The thermal and optical-physical properties of these crystals were investigated. All the three solvates could transform into the β polymorph after desolvation, but the pure β polymorph could be isolated only from the formic acid solvate. The optical properties are closely related to the pyrene fluorophore stacking modes and intermolecular interactions in the solid-state. The immobilization of pyrene fluorophores may be responsible for the high quantum yields.

Tetrakis(1H-imidazole-κN3)(2-phenylpropanedioato-κ2O1,O3)nickel(II)

In the title complex, [Ni(C9H6O4)(C3H4N2)4], the NiII ion is O,O′-chelated by the phenylmalonato ligand and coordinated by four imidazole ligands in a slightly distorted octahedral geometry. In the crystal structure, symmetry-related molecules are linked by N—H⋯O hydrogen bonds, generating a three-dimensional network.

Tetra­kis(1H-imidazole-κN 3)(2-phenyl­propanedioato-κ2 O 1,O 3)nickel(II)

In the title complex, [Ni(C9H6O4)(C3H4N2)4], the NiII ion is O,O′-chelated by the phenylmalonato ligand and coordinated by four imidazole ligands in a slightly distorted octahedral geometry. In the crystal structure, symmetry-related molecules are linked by N—H⋯O hydrogen bonds, generating a three-dimensional network.

Tetra-kis(1H-imidazole-κN)(2-phenyl-propanedioato-κO,O)nickel(II).

In the title complex, [Ni(C9H6O4)(C3H4N2)4], the NiII ion is O,O′-chelated by the phenylmalonato ligand and coordinated by four imidazole ligands in a slightly distorted octahedral geometry. In the crystal structure, symmetry-related molecules are linked by N—H⋯O hydrogen bonds, generating a three-dimensional network.

Tetra­kis(1H-imidazole-κN3)(2-phenyl­propanedioato-κ2O1,O3)nickel(II)

In the title complex, [Ni(C9H6O4)(C3H4N2)4], the NiII ion is O,O′-chelated by the phenylmalonato ligand and coordinated by four imidazole ligands in a slightly distorted octahedral geometry. In the crystal structure, symmetry-related molecules are linked by N—H⋯O hydrogen bonds, generating a three-dimensional network.