Kinds Of Coordination Polymers Research Articles

Synthesis of Cu and Zr-based coordination polymers with N/O donors and investigation of their photocatalytic activity against dye

The coordination polymers (CPs) of Cu and Zr were synthesized by the hydrothermal method. The orotic acid potassium salt (H3KL) was used as a linker, which coordinates via O-O. Whereas, 4,4′-trimethylenedipyridine (4,4′-TMDP) was used as a bifunctional monomer, which coordinates via N-N. The synthesized CPs were characterized by FTIR, P-XRD, TGA, DSC and SEM. The photocatalytic activity was investigated against methylene blue (MB) under sunlight irradiation. Both Cu-CP and Zr-CP exhibited potential activity for the degradation of MB, which was 72% for Cu-CP and 93% for Zr-CP. The band gap of the CPs was also investigated, and the observed value was 2.2 eV. The band gap indicates that these compounds could bring breakthroughs as photocatalysts instead of semiconductors. These kinds of CPs could be used for multiple purposes in industry and in a green environment.

Syntheses, Structures, and Properties of Coordination Polymers with 2,5-Dihydroxy-1,4-Benzoquinone and 4,4'-Bipyridyl Synthesized by In Situ Hydrolysis Method.

The coordination polymers (CPs) with binary ligands, including 2,5-dihydroxy-1,4-benzoquinone (H2DHBQ) and 4,4′-bipyridyl (bpy), were synthesized using in situ hydrolysis of 2,5-dimethoxy-1,4-benzoquinone (DMBQ). Three kinds of CPs were obtained depending on the metal ions. For M = Mn and Zn, a 1D zigzag chain structure with cis conformation (cis-1D-M) was obtained, whereas Co, Ni, and Cu compounds afforded a 2D net structure with trans conformation (trans-2D-M) with a 1D pore. A linear chain structure was also obtained for M = Cu. Magnetic susceptibility (χMT) at 300 K in cis-1D-Mn and trans-2D-Co was evaluated to be 4.421 and 2.950 cm3 K mol–1, respectively, indicating that both compounds are in the high-spin state. According to the N2 adsorption isotherms at 77 K, trans-2D-Ni showed microporosity with the BET surface area of 177 m2 g–1, whereas the isomorphic trans-2D-Co rarely adsorbed N2 at 77 K. This phenomenon was explained by the difference of diffusion kinetics of the adsorbent molecules, which was supported by the CO2 adsorption isotherms at 195 K. The optical band gaps of cis-1D-Mn, cis-1D-Zn, trans-2D-Co, and trans-2D-Ni were estimated to be 1.6, 1.8, 1.0, and 1.1 eV, respectively, by using UV–vis–NIR spectroscopy.

Lanthanide ion exchange properties of a coordination polymer consisting of di(2-ethylhexyl) phosphoric acid and trivalent metal ions (Ce3+, Fe3+, or Al3+)

Three kinds of coordination polymers ([M(dehp)3], M = Ce, Fe, or Al) were prepared by mixing the sodium form (Na(dehp)) of di(2-ethylhexyl) phosphoric acid and MCl3 in an ethanol-water binary mixture. They have monoclinic crystalline structure with similar lattice parameters. The lanthanide ion (Ln(3+) = La(3+), Sm(3+), Dy(3+), or Yb(3+)) exchange properties were studied in a 20 : 80 vol% ethanol-water binary mixture containing 2 mM Ln(NO3)3 at room temperature. The rate of Ln(3+) adsorption is relatively slow; it requires over 3 weeks to reach equilibrium. [M(dehp)3] has different Ln(3+) affinities depending on the kind of central metal ions: the affinity order at 3 week adsorption is Yb(3+) < La(3+) < Dy(3+) < Sm(3+) for [Ce(dehp)3], La(3+) < Sm(3+) < Dy(3+) < Yb(3+) for [Fe(dehp)3], and La(3+) < Sm(3+), Dy(3+), Yb(3+) for [Al(dehp)3]. The difference in affinity order can be explained by two factors: the coordination preference and steric strain caused by the polymeric structure. The chemical and structural analyses suggested that the Ln(3+) adsorption progresses first by the central M(3+)/Ln(3+) exchange, followed by a morphological change to a rod-like or fibrous form by a solid phase reaction. In the case of [Fe(dehp)3], the eluted Fe(3+) may be hydrolyzed and precipitated as amorphous iron hydroxide.

Homo-chiral self-assemblies and magnetic studies of M(II)-2,2′-bipyridine-4,4′-dicarboxylate coordination polymers

Abstract Homochiral self-assembly is a challenging task, especially from achiral components without any chiral auxiliary. Based on rational selection of achiral organic ligand, two kinds of chiral coordination polymers, {Mn(o1,o2-μ-bpdc)(H2O)2}n (1) and {Ni(o1,o1′-μ-bpdc)(H2O)2}n (2) (bpdc = 2,2′-bipyridine-4,4′-dicarboxylate), have been successfully synthesized by hydrothermal reaction. The X-ray single crystal determination and the structural insight indicate that the coordination behaviors of both bpdc ligands and metal ions between the two kinds of coordination polymers are distinct. Temperature dependent magnetic studies reveal that Mn(II) ions in 1 show antimagnetic interactions, while Ni(II) ions in 2 show weakly ferromagnetic interactions.

Synthesis and structural determination of three metal-organic frameworks in a Co-3-amino-1,2,4-triazole system

The hydrothermal reactions of cobalt(II) salts with 3-amine-1H-1,2,4-triazole (Hatrz) result in two kinds of coordination polymers, namely, 2D isoreticular layers based on a binuclear unit Co(atrz)Br ( 1) and Co(atrz)I ( 2), and 3D alternating layer architecture of Co 5(atrz) 7(N 3) 3 ( 3), which were structurally characterized by single-crystal X-ray diffraction techniques. Thermostabilities of all compounds were examined by thermogravimetric analysis. Isostructural compounds 1 and 2 display a two-dimensional layer structure where Co centers are linked by μ 1,2,4-atrz anions to form isoreticular layers containing sixteen-membered rings. Compound 3 is a 3D alternating layer architecture, which are based on parallel 1D chains and bimetal unit [N 3Co-(μ 1,4-atrz)-CoN 3]. The thermogravimetric analysis results of compounds 3 show that tremendous heat is released from its thermal decomposition, which indicates that the compound qualifies as a high-energy candidate.

Crystallographic report: Coordination polymers containing Cd(NO3)2 and Cd(H2O)22+ units bridged by btp ligands (btp = 2,6‐bis(N′‐1,2,4‐triazolyl)pyridine)

AbstractThere are two kinds of coordination polymers in the title compound: one contains Cd(NO3)2 units bridged by 2,6‐bis(N′‐1,2,4‐triazolyl)pyridine (btp) ligands and the other contains Cd(H2O)22+ bridged by btp ligands. The two coordination polymers are connected through hydrogen bonds. Copyright © 2004 John Wiley &amp; Sons, Ltd.