Chun-Hua Zhang

Adsorption of uranium(VI) from aqueous solution by diethylenetriamine-functionalized magnetic chitosan

In this paper, the modified magnetic chitosan resin containing diethylenetriamine functional groups (DETA-MCS) was used for the adsorption of uranium ions from aqueous solutions. The influence of experimental conditions such as contact time, pH value and initial uranium(VI) concentration was studied. The Langmuir, Freundlich, Sips and Dubinin–Radushkevich equations were used to check the fitting of adsorption data to the equilibrium isotherm. The best fit for U(VI) was obtained with the Sips model. Adsorption kinetics data were tested using pseudo-first-order and pseudo-second-order models. Kinetic studies showed that the adsorption followed the pseudo-second-order kinetic model, indicating that the chemical adsorption was the rate-limiting step. The present results suggest that DETA-MCS is an adsorbent for the efficient removal of uranium(VI) from aqueous solution.

Hydrothermal syntheses, crystal structures and properties of two cobalt(II) complexes constructed from 5-(isonicotinamido)isophthalic acid

Two Co(II) complexes, [Co(INAIP)(dib)]·4H2O and [Co(INAIP)(phen)(H2O)]·H2O have been synthesized by the reaction of 5-(isonicotinamido)isophthalic acid (H2INAIP) and CoSO4·7H2O, as well as N-donor ligands, namely 1,4-di(1-imidazolyl)benzene (dib) and 1,10-phenanthroline (phen) under hydrothermal conditions. Single-crystal X-ray diffraction analysis indicates that [Co(INAIP)(dib)]·4H2O has a two-dimensional (2D) double-layer network structure with a (4, 4) topology, while [Co(INAIP)(phen)(H2O)]·H2O displays a one-dimensional chain structure, extending to a 2D net through the π–π interactions. In addition, the photoluminescence and degradation of methyl orange in a Fenton-like process using the complexes as catalysts were investigated.

Hydrothermal Synthesis, Crystal Structure, and Luminescence Property of an Mn-Tb Complex Based on 5-(isonicotinamido)-isophthalate

A 3d-4f heterometallic coordination polymer, [Mn0.5Tb (INAIP)2(H2O)2]·2H2O (1) has been prepared by hydrothermal reactions of the corresponding lanthanide salt with 5-(isonicotinamido)isophthalic acid (H2INAIP) in the presence of MnSO4·H2O and NaOH. X-ray single-crystal structural analysis reveals that 1 features non-interpenetrated three-dimensional (3D) coordination framework containing two-dimensional (2D) (4, 4) Tb-carboxylate layers. In addition, 1 also displayed photoluminescent properties in the green range at room temperature.

Poly[[tetra-aquatetrakis-[μ(3)-5-(pyridine-4-carboxamido)-isophthalato]cobalt(II)digadolinium(III)] tetra-hydrate].

In the centrosymmetric polymeric title compound, {[CoGd2(C14H8N2O5)4(H2O)4]·4H2O}n, the GdIII cation is coordinated by one water molecule and four pyridine-4-carboxamidoisophthalate (L) anions in a distorted square-antiprismatic arrangement, while the CoII cation, located on an inversion center, is coordinated by two pyridyl-N atoms, two carboxylate-O atoms and two water molecules in a distorted octahedral geometry. The asymmetric unit contains two anionic L ligands: one bridges two Gd cations and one Co cation through two carboxyl groups and one pyridine-N atom; the other bridges two Gd cations and one Co cation through two carboxyl groups and the uncoordinated pyridine-N atom is hydrogen-bonded to the adjacent coordinated water molecule. Extensive O—H⋯O and N—H⋯O hydrogen bonds are present in the crystal structure.

Syntheses, crystal structures and properties of two nickel(II) coordination polymers constructed from 5-(isonicotinamido)isophthalic acid

Two Ni(II) metal–organic frameworks, [Ni(INAIP)(DMF)]·0.5DMF and [Ni(INAIP)(H2O)]·2H2O, have been synthesized by the reaction of 5-(isonicotinamido)isophthalic acid (H2INAIP) with NiSO4·6H2O using different reaction solvents. Single-crystal X-ray diffraction analysis indicates that [Ni(INAIP)(DMF)]·0.5DMF has a twofold interpenetrated three-dimensional (3D) framework with sra topology, while [Ni(INAIP)(H2O)]·2H2O has a two-dimensional (2D) network structure with a 4-connected (43·63) topology. In addition, the magnetic and adsorption properties of the complexes were explored.

Poly[diaqua[μ4-4-(isonicotinamido)phthalato]nickel(II)] displaying an sra topology.

In the title compound, [Ni(C14H8N2O5)(H2O)2]n, the Ni(II) cation is six-coordinate with a slightly distorted octahedral coordination geometry and the 4-(isonicotinamido)phthalate ligand links the Ni(II) centres into a three-dimensional structure with sra topology. The structure is also stabilized by N-H···O hydrogen bonding between the uncoordinated amide groups of the ligand and extensive O-H···O hydrogen bonding between the two coordinated water molecules. The magnetic and thermal stability properties of the title compound are also discussed.

Synthesis, structure and properties of a two-dimensional iron(II) metal-organic framework

Reaction of FeSO4·7H2O with 5-(isonicotinamido)isophthalic acid (H2INAIP) in the presence of NaOH results in the formation of a two-dimensional network [Fe(INAIP)(H2O)]n·2nH2O. In the complex, each INAIP2− ligand links three Fe(II) atoms to give a double-chain structure using its two carboxylate groups in μ1–η1:η1 and μ2–η1:η1 coordination modes. The chains are interlinked to form a layer structure through Fe–N interactions, which it is extended to a three-dimensional supramolecular structure by H-bonding interactions. The thermal and magnetic properties of the complex were investigated, and antiferromagnetic interactions were observed. Moreover, the adsorption behavior shows that the title complex has obviously selective adsorption of CO2 over N2 after the removal of the solvent molecules within the pores.

Aqua-(2,2'-bipyridine-κ(2)N,N'){(E)-[(5-chloro-2-oxidobenzyl-idene)amino-κ(2)N,O]methane-sulfonato-κO}zinc.

In the title compound, [Zn(C8H6ClNO4S)(C10H8N2)(H2O)], the ZnII atom is six-coordinated by two O atoms and one N atom from a tridentate Schiff base ligand and two N atoms from a chelating 2,2′-bipyridine ligand and one water molecule, forming a slightly distorted octahedral geometry. In the crystal, O—H⋯O hydrogen bonds link pairs of complex molecules into dimers. An intramolecular O—H⋯O hydrogen bond is also present.

Structure andMagnetic Properties of a Three-dimensional Metal-organic Framework: [Co(L)(H2O)2]·H2O

A unique 3D fourfold interpenetrated metal-organic framework, [Co(L)(H2O)2]・H2O (1), has been synthesized by the solvothermal reaction of H2L with Co(NO3)2・6H2O (H2L = 5-(isonicotinamido) isophthalic acid). Compound 1 crystallizes in the monoclinic space group P21/c, with the cell parameters: a = 81301(8), b = 107711(11), c = 167697(16) Å , β = 92.656(2) °, V = 14669(3) Å3, R1 = 0.0325 and wR2 = 0.0833. Its framework has (10,3)-b topology, where the cobalt atoms are alternately bridged by the pyridyl and the carboxylate groups of the L2− ligands into a three-dimensional network. Compound 1 displays antiferromagnetic interactions. Above 40 K, χm −1 obeys the Curie- Weiss law with C = 3.28 emu Kmol−1 andΘ = −0.66 K. Graphical Abstract Structure andMagnetic Properties of a Three-dimensional Metal-organic Framework: [Co(L)(H2O)2]·H2O

Structure and Magnetic Properties of a Three-dimensional Cobalt Metal-Organic Framework

A new 3D fourfold interpenetrated metal-organic framework, [Co(L)2(SO4)]・H2O (1), has been synthesized by the solvothermal reaction of L with CoSO4・6H2O (L = 1,4-bis(imidazolyl)benzene). Compound 1 crystallizes in the monoclinic space group P21/n, with the cell parameters: a = 9.943(2), b = 21.7104(15), c = 13.2658(18) Å , β = 97.638(3)◦, V = 2838.2(8) Å3, R1 = 0.0566 and wR2 = 0.1035. It represents a novel dia net, in which the cobalt atoms are alternately bridged by the imidazolyl N atoms of the ligands L into a three-dimensional network. Compound 1 displays antiferromagnetic interactions. From 2 to 300 K, χm −1 it obeys the Curie-Weiss law with C =2.68 emu K mol−1 and Θ = −2.59 K Graphical Abstract Structure and Magnetic Properties of a Three-dimensional Cobalt Metal-Organic Framework