Dong-Yu Lv

Synthesis, structural versatility, luminescent and magnetic properties of a series of coordination polymers constructed from biphenyl-2,4,4′-tricarboxylate and different N-donor ligands

Eight new coordination polymers [Mn(H2btc)2(4,4′-bpy)2]n (1), {[Cd(Hbtc)(phen)(H2O)]·H2O}n (2), [Pb(Hbtc)(phen)]n (3), {[Cd3(btc)2(H2O)5]·4H2O}n (4), {[Cd3(btc)2(phen)2(H2O)]·H2O}n (5), [Mn3(btc)2(2,2′-bpy)2]n (6), {[Ni3(btc)2(4,4′-bpy)2.5(μ2-H2O)(H2O)3]·3H2O}n (7), and {[Co2(btc)(μ3-OH)(μ2-H2O) (8), were assembled from different metal(II) chlorides and biphenyl-2,4,4′-tricarboxylic acid (H3btc) as a main building block, and various aromatic N-donors (phen = 1,10-phenanthroline, 4,4′-bpy = 4,4′-bipyridine, 2,2′-bpy = 2,2′-bipyridine) as supporting ligands. By adjusting the reaction pH, H3btc undergoes a partial deprotonation to give the H2btc− form in 1, and the Hbtc2− moiety in 2 and 3, and the fully deprotonated btc3− form in 4–8. All the products were fully characterized by single crystal X-ray diffraction analysis. Compounds 1 and 2 possess the double helical chain and wheel chain 1D coordination networks, respectively, which are further extended into the 3D supramolecular architectures via hydrogen bonds. The 2D and 3D metal–organic networks of 6 and 3 were topologically classified, revealing the trinodal 3,6,6-connected and uninodal 4-connected nets with the 3,6,6L3 and sra topologies, respectively. Compounds 4, 5, 7, and 8 feature the very complex 3D metal–organic framework structures, generating either pentanodal 3,4,5,6,6- (4), 3,3,4,5,5- (5), and 4,4,4,5,6-connected (7), or tetranodal 3,5,6,6-connected (8) underlying nets with the hitherto undocumented topologies. The obtained data revealed that different coordination modes of the H2btc−/Hbtc2−/btc3− ligands and the resulting crystal architectures depend on a variety of factors, such as the solution pH and the nature of metal ions and N-donor auxiliary ligands. Magnetic susceptibility measurements indicate that 1 and 8 show a dominating ferromagnetic coupling, while 6 and 7 exhibit an antiferromagnetic coupling between the metal centers. Furthermore, thermal stability of 1–8 and luminescent properties of 2–5 were also studied and discussed.

Lanthanide coordination polymers based on 5-(2′-carboxylphenyl) nicotinate: syntheses, structure diversity, dehydration/hydration, luminescence and magnetic properties

Twelve lanthanide coordination polymers associated with the organic ligand 5-(2′-carboxylphenyl) nicotinic acid (H2cpna): {[Ln(Hcpna)(cpna)(phen)]·H2O}n (Ln = Sm (1), Tb (2), Ho (3), phen = 1,10-phenanthroline), {[Sm(Hcpna)(cpna)(phen)]·2H2O}n (4), {[Ln2(cpna)3(H2O)3]·4H2O}n (Ln = Y (5), Tb(6), Dy (7), Ho (8)), [Lu2(cpna)3(H2O)2]n (9), {[Y2(cpna)3(phen)2(H2O)]·H2O}n (10), and [Ln(cpna)(phen)(NO3)]n (Ln = Tm (11), Lu (12)) have been prepared by hydrothermal methods and structurally characterized. The structure analyses reveal that complexes 1–3 are isostructural and possess unique three-dimensional (3D) frameworks based on the dodecanuclear Sm/Tb/Ho macrocycles. Complex 4 exhibits a one-dimensional (1D) wheel-chain structure, which further builds three-dimensional (3D) supramolecular architecture via O–HN hydrogen-bonding interactions. Complexes 5–8 are also isostructural and display three-dimensional (3D) open frameworks, which possess two types of channels along the a- and b-axis, respectively. Complexes 9 and 10 feature three-dimensional (3D) frameworks and are created from tetranuclear and dinuclear units, respectively. Complexes 11 and 12 are isostructural and demonstrate one-dimensional (1D) double chain structures, which further build three-dimensional (3D) supramolecular architecture via C–H···O hydrogen-bonding. The results show that the pH value of the reaction system, anion, auxiliary ligand and lanthanide contraction play a significant role in determining the structures of the complexes. In addition, the results of luminescent measurements for compounds 2 and 6 in the solid state at room temperature indicate that the different types of structures have a dissimilar influence on their characteristic luminescence. The magnetic properties of compounds 1, 3, 4, 7 and 11 have been investigated. Furthermore, thermal stabilities for 1–12 and the dehydration/hydration properties of compound 6 have also been studied.

Determination of L-aspartic acid by using the Cu(II)-catalyzed oscillating reaction

A convenient procedure by means of oscillating chemical system as an analytical tool to determine the L-aspartic acid (L-Asp) is proposed. The system involves the Cu(II)-catalyzed reaction between hydrogen peroxide and sodium thiocyanate in an alkaline medium. The method relies on the linear relationship between the changes in the oscillation period and the logarithm of concentration of L-aspartic acid. Optimized conditions were further validated to ensure the reliability of the method. Under optimum conditions, the calibration plot is linearly proportional to the concentration of L-aspartic acid over the range from 1.17 × 10-5 mol L-1 to 7.10 × 10-8 mol L-1 with a corresponding regression coefficient of 0.9990 (RSD 2.75%). A lower limit of determination (LOD) was 5.58 × 10-8 mol L-1. The proposed method has been used to determine L-aspartic acid in drug sample. Additionally, the HPLC technique was also used to confirm the determination results.

Poly[[triaqua­(μ3-4-oxidopyridine-2,6-dicarboxyl­ato)thulium(III)] monohydrate]

In the title coordination polymer, {[Tb(C7H2NO5)(H2O)3]·H2O}n, the TbIII atom is eight-coordinated by a tridentate 4-oxidopyridine-2,6-dicarboxylate trianion, two adjacent monodentate anions and three water molecules, forming a distorted bicapped trigonal–prismatic TbNO7 coordination environment. The anions bridge adjacent TbIII ions into double chains. Adjacent chains are further connected into sheets parallel to (10). O—H⋯O hydrogen bonds involving both coordinated and uncoordinated water molecules generate a three-dimensional network.

Determination of sulfanilamide based on the Mn(II)-catalyzed oscillating chemical reaction

A convenient and sensitive method for determination of sulfanilamide (SNA) was described based on the Mn(II)-catalyzed oscillating chemical reaction. Under optimum conditions, a linear relationship existed between the changes of oscillating period or amplitude and the negative of logarithm of SNA concentration in the range of 4.27 × 10−8 mol ·L−1 ∼ 7.41 × 10−6 mol ·L−1 (RSD, 0.85%) and 9.33 × 10−8 mol ·L−1 ∼ 3.02 × 10−6 mol ·L−1 (RSD, 1.08%), respectively. The lower limit of detection was found to be 2.69 × 10−8 mol ·L−1 and 6.03 × 10−8 mol ·L−1, respectively.

Two Lanthanide Coordination Polymers Constructed from Diphenic Acid: Syntheses, Crystal Structures, and Magnetic Properties

Two lanthanide(III) coordination polymers, [Ln2(dpa)3 (H2O)2]n (Ln = Pr, 1; Ce, 2), were self-assembled from diphenic acid (H2dpa) and corresponding lanthanide(III) salts under hydrothermal conditions. The compounds were found to be isostructural. Single-crystal X-ray diffraction studies show that both compounds are one-dimensional chain structures, which are further extended into three-dimensional supramolecular frameworks through π − π interactions. Magnetic studies for complex 1 show weaker antiferromagnetic coupling between the Pr(III) ions.

Poly[[triaqua-(μ(3)-4-oxidopyridine-2,6-dicarboxyl-ato)europium(III)] monohydrate].

In the title coordination polymer, {[Ho(C7H2NO5)(H2O)3]·H2O}n, the HoIII atom is eight-coordinated by a tridentate 4-oxidopyridine-2,6-dicarboxylate trianion, two monodentate anions and three water molecules, forming a distorted bicapped trigonal–prismatic HoNO7 coordination geometry. The anions bridge adjacent HoIII ions into double chains. Adjacent chains are further connected into sheets. O—H⋯O hydrogen bonds involving both coordinated and uncoordinated water molecules generate a three-dimensional supramolecular framework.

Poly[diaqua-tris-(μ(4)-1,3-phenyl-enediacetato)-dineodymium(III)].

In the title coordination polymer, [Nd2(C10H8O4)3(H2O)2]n, each of the two NdIII ions is nine-coordinated by eight O atoms from six different 2,2′-(m-phenylene)diacetate (pda) bivalent anions and by one O atom from a water molecule, forming a distorted tricapped trigonal–prismatic coordination geometry. Eight NdIII ions and 12 pda ligands form a large [Nd8(pda)12] ring, and four NdIII ions and six pda ligands form a small [Nd4(pda)6] ring. These rings are further connected by the coordination interactions of pda ligands and NdIII, generating a three-dimensional supramolecular framework.