Qingfu Zhang

DMF/H2O Volume-Ratio-Controlled Assembly of 2D and 3D Ln-MOFs with 5-(Pyridin-4-yl)isophthalic Acid Ligand

Through middle-temperature solvothermal reactions of Ln(NO3)3·6H2O (Ln = Tb and Eu) with 5-(pyridin-4-yl)isophthalic acid (H2PIA), three Ln-MOFs [Tb(HPIA)(PIA)(H2O)2]n·0.5nH2O (1), [Eu(HPIA)(PIA)(H2O)2]n·0.5nH2O (2), and [Tb2(PIA)3(H2O)4]n·3nH2O (3) were obtained using DMF/H2O volume ratios of 1 : 54, 1 : 54, and 1 : 7, respectively. Single-crystal X-ray diffraction analysis reveals that complexes 1 and 2 are isostructural and display a 2D uninodal 4-connected undulated sql topology with Ln3+ ions as nodes, while complex 3 exhibits a 3D uninodal 6-connected pcu topology with dinuclear octahedral [Tb2(CO2)6] secondary building units as nodes. Obviously, the DMF/H2O volume ratio plays an essential role in the crystallisation and construction of these coordination frameworks with distinct dimensionality and connectivity. The thermal and photoluminescence properties of complexes 1–3 in the solid state are also discussed.

A Chain-Based 2 D Cobalt(II) Coordination Polymer with a “Crab-Like” Flexible Dicarboxylate Ligand: A Weak Ferromagnetic Single-Chain Magnet

Chain gang: A chain-based 2D Co(II) coordination polymer was prepared by hydrothermal reaction of Co(NO3)2⋅6 H2O, H2L and bpa in the presence of sodium hydroxide. Magnetic investigation revealed canted antiferromagnetism, magnetic hysteresis, and slow magnetic relaxation. Thus, this complex could be considered as a new homospin weak ferromagnetic single-chain magnet.

Formation and properties of wormlike micelles in solutions of a cationic surfactant with a 2-hydroxypropoxy insertion group

The rheological properties of aqueous solutions of a cationic surfactant, 3-hexadecyloxy-2-hydroxypropyl trimethyl ammonium bromide (R16HTAB), and its mixed solution system with sodium salicylate (NaSal) have been studied by using steady state and frequency sweep rheological measurements. The microstructure of the formed wormlike micelles has been ascertained by transmission electronic microscopy and 1H NMR technology. The effects of the surfactant concentration, added salt, temperature and different counterions on the viscoelastic solutions have been systematically investigated. In a salt-free state, the η0 and R16HTAB concentrations obey the relationship of the power law, i.e. η0 ∝ C2.53, in the examined concentration range. The addition of NaSal greatly promoted the micellar growth in R16HTAB aqueous solution and resulted in the generation of wormlike micelles. The causes of the formation of wormlike micelles and the strong network structure have been analyzed.

A Water-Stable 3D Luminescent Metal−Organic Framework Based on Heterometallic [EuIII6ZnII] Clusters Showing Highly Sensitive, Selective, and Reversible Detection of Ronidazole

A water-stable 3D luminescent metal-organic framework (MOF), [Eu6Zn(μ3-OH)8(NDC)6(H2O)6]n (1), constructed from heterometallic [EuIII6ZnII] clusters and electron-rich π-conjugated 1,4-naphthalenedicarboxylic acid (H2NDC) ligands exhibits highly sensitive, selective, and reversible detection of ronidazole, which represents the first example of luminescent MOFs based on Ln-TM heterometallic clusters for the detection of antibiotics in aqueous solution.

Formation and characteristics of aqueous two-phase systems formed by a cationic surfactant and a series of ionic liquids

Aqueous two-phase systems (ATPS) were obtained in the aqueous mixtures of a cationic surfactant and a series of ionic liquids (ILs). The effects of IL structure, temperature and additives on the phase separation were systematically investigated. The microstructures of some ATPS were observed by freeze-fracture replication technique. Lyotropic liquid crystal was found in the bottom phase besides micelles under different conditions. Remarkably, both IL structure and additives profoundly affected the formation and properties of the ATPSs. The phase separation can be attributed to the existence of different aggregates and the cation-π interactions of the cationic surfactant with the ILs, which has a significant role in the formation of ATPS. The extraction capacity of the studied ATPS was also evaluated through their application in the extraction of two biosubstances. The results indicate that the ILs with BF4(-) as anion show much better extraction efficiencies than the corresponding ILs with Br(-) as anion do under the same conditions. l-Tryptophan was mainly distributed into the NPTAB-rich phase, while methylene blue and capsochrome were mainly in the IL-rich phase.

Coexistence of self- and interpenetration in two (3,6)-connected porous coordination polymers

Two isostructural (3,6)-connected porous coordination polymers topologically featuring both self- and interpenetration have been successfully synthesized. The porous material shows a reversible crystalline-to-amorphous transition associated with the removal and recapture of guest molecules. Particularly, the porous material demonstrates selective detection of nitrobenzene through fluorescence quenching.

A twofold interpenetrated 3-D Cu(II) coordination polymer based on 5-(pyridin-4-yl)isophthalic acid: synthesis, crystal structure, and magnetic properties

Abstract A new copper(II) coordination polymer, [Cu(PIA)·2H2O]n (1) [H2PIA = 5-(pyridin-4-yl)isophthalic acid], has been synthesized and characterized by elemental analysis, IR spectroscopy, TGA, powder, and single-crystal X-ray diffraction. Structural analysis shows that each PIA2− in 1 bridges three Cu(II) ions, and likewise each Cu(II) ion connects to three PIA2− ligands, giving a 3-D framework with utp topology and left-/right-handed helical channels. Interestingly, two such identical frameworks interlock with each other to generate a twofold interpenetrated structure that is stabilized by hydrogen bonding and π–π interactions. In addition, the thermal stability and the magnetic properties of 1 have been investigated. Graphical abstract

A two-dimensional cadmium(II) coordination polymer based on 5-(pyridin-4-yl)isophthalic acid: poly[[tetraaquabis[μ₃-5-(pyridin-4-yl)isophthalato]dicadmium(II)] pentahydrate].

The title Cd(II) compound, {[Cd2(C13H7NO4)2(H2O)4]·5H2O}n, was synthesized by the hydrothermal reaction of Cd(NO3)2·4H2O and 5-(pyridin-4-yl)isophthalic acid (H2L). The asymmetric unit contains two crystallographically independent Cd(II) cations, two deprotonated L(2-) ligands, four coordinated water molecules and five isolated water molecules. One of the Cd(II) cations adopts a six-coordinate octahedral coordination geometry involving three O atoms from one bidentate chelating and one monodentate carboxylate group of two different L(2-) ligands, one N atom of another L(2-) ligand and two coordinated water molecules. The second Cd(II) cation adopts a seven-coordinate pentagonal-bipyramidal coordination geometry involving four O atoms from two bidentate chelating carboxylate groups of two different L(2-) ligands, one N atom of another L(2-) ligand and two coordinated water molecules. Each L(2-) ligand bridges three Cd(II) cations and, likewise, each Cd(II) cation connects to three L(2-) ligands, giving rise to a two-dimensional graphite-like 6(3) layer structure. These two-dimensional layers are further linked by O-H···O hydrogen-bonding interactions to form a three-dimensional supramolecular architecture. The photoluminescence properties of the title compound were also investigated.

A one-dimensional silver(I) coordination polymer based on an asymmetric flexible N-donor carboxylate ligand: catena-poly[(μ3-4-{[(1-phenyl-1H-tetrazol-5-yl)sulfanyl]methyl}benzoato-κ(3)O:O':N(4))silver(I)].

The title compound, [Ag(C15H11N4O2S)]n, was synthesized by the reaction of 4-{[(1-phenyl-1H-tetrazol-5-yl)sulfanyl]methyl}benzoic acid (Hptmba) with silver nitrate and triethylamine at room temperature. The asymmetric unit contains one crystallographically independent Ag(I) cation and one ptmba(-) ligand. Each Ag(I) cation is tricoordinated by two carboxylate O atoms and one tetrazole N atom from three different ptmba(-) ligands, displaying a distorted T-shaped geometry. Three Ag(I) cations are linked by tris-monodentate bridging ptmba(-) ligands to form a one-dimensional double chain along the c axis, which is further consolidated by an intrachain π-π contact with an offset face-to-face distance of 4.176 (3) Å between the centroids of two adjacent aromatic rings in neighbouring benzoate groups. The one-dimensional chains are linked into a three-dimensional supramolecular framework by additional π-π interchain interactions, viz. of 3.753 (3) Å between two phenyl substituents of the tetrazole rings and of 4.326 (2) Å between a benzoate ring and a tetrazole ring. Thermogravimetric analysis and the fluorescence spectrum of the title compound reveal its good thermal stability and a strong green luminescence at room temperature.

CCDC 806037: Experimental Crystal Structure Determination

Related Article: Suna Wang, Ruirui Yun, Yanqiang Peng, Qingfu Zhang, Jing Lu, Jianmin Dou, Junfeng Bai, Dacheng Li, Daqi Wang|2012|Cryst.Growth Des.|12|79|doi:10.1021/cg2008057