Yu-Ling Wang

Two novel luminescent silver(I) coordination polymers containing octanuclear silver cluster units or ligand unsupported Ag⋯Ag interactions constructed from 5-sulfoisophthalic acid (H3SIP) and organic amine

Self-assembly of Ag(NO3)2 with 5-sulfoisophthalic acid monosodium salt (NaH2SIP) in the presence of piperazine (pip) or 4,4′-bipyridyl (bpy) produced two new silver(I) coordination polymers, {(H2pip)2[Ag8(SIP)4(H2O)4](H2O)4}n (1) and {[Ag(bpy)][Ag(HSIP)(bpy)](H2O)2}n (2), respectively. Single-crystal X-ray diffraction reveals that compound 1 has a 2D silver carboxylate-sulfonate layered structure containing an uncommon octanuclear [Ag8(CO2)8] cluster wherein the eight silver(I) atoms form two intersecting Ag4 planes. The 2D layers are further linked by the H2pip molecules through hydrogen bonds into a 3D supramolecular structure. Compound 2 features a 2D supramolecular network formed by silver(I)-bpy double chains and HSIP ligands through the combination of coordination bonds, ligand unsupported Ag⋯Ag interactions and weak Ag⋯O coordinative interactions. In the solid state at room temperature, compound 1 exhibits blue photoluminescence with a maximum at 450 nm upon excitation at 365 nm. Compound 2 shows green photoluminescence with a maximum at 564 nm upon excitation at 392 nm.

Diversity of lanthanide(III)-2,5-dihydroxy-1,4-benzenedicarboxylate extended frameworks: syntheses, structures, and magnetic properties.

Six lanthanide(III)-2,5-dihydroxy-1,4-benzenedicarboxylate frameworks, namely, [Ln(H(2)-DHBDC)(1.5)(H(2)O)(2)](n) (Ln = La (1) and Pr (2); H(4)-DHBDC = 2,5-dihydroxy-1,4-benzenedicarboxylic acid), {[Nd(H(2)-DHBDC)(1.5)(H(2)O)(3)](H(2)O)}(n) (3), {[Eu(H(2)-DHBDC)(NO(3))(H(2)O)(4)](H(2)O)(2)}(n) (4), and {[Ln(2)(H(2)-DHBDC)(2)(DHBDC)(0.5)(H(2)O)(3)](H(2)O)(4)}(n) (Ln = Gd (5) and Dy (6)), with four different structural types ranging from 1D chain, 2D layer to 3D networks have been synthesized and structurally characterized. Compounds La (1) and Pr (2) are isomorphous and exhibit 3D frameworks with the unique 1D tubular channels. Compounds Nd (3) and Eu (4) are 2D layer and 1D zigzag chain, respectively, which are further extended to 3D supramolecular frameworks through extensive hydrogen bonds. Isomorphous compounds of Gd (5) and Dy (6) are 3D frameworks constructed from secondary infinite rod-shaped metal-carboxylate/hydroxyl building blocks. While the hydroxyl groups as secondary functional groups in the 1D chain of Eu (4) and 2D layer of Nd (3) are not bonded to the lanthanide centers, the hydroxyl groups in the 3D frameworks of La (1), Pr (2), Gd (5), and Dy (6) participate in coordinating to lanthanide centers and thus modify the structural types of theses compounds. The magnetic data of compounds Pr (2), Nd (3), Gd (5), and Dy (6) have been investigated in detail. In addition, elemental analysis, IR spectra, powder X-ray diffraction (PXRD) patterns and thermogravimetric analysis of these compounds are described.

Metal oxo cluster-based coordination polymers with rigid 1,4-naphthalenedicarboxylate and semirigid 1,3-di(4-pyridyl)propane ligands: syntheses, structural topologies, and luminescent properties

Hydrothermal reactions of Zn(NO3)2 or Pb(NO3)2 with 1,4-naphthalenedicarboxylic acid (1,4-H2ndc) and 1,3-di(4-pyridyl)propane (dpp) lead to two novel metal oxo cluster-based coordination polymers, namely, [Zn5(μ3-OH)2(1,4-ndc)4(dpp)2]n (1) and [Pb5(μ4-O)(1,4-ndc)4(dpp)]n (2). The structures exhibit different cluster motifs depending on the nature of the metal ions. Compound 1 features a 3D structure based on the pentanuclear [Zn5(μ3-OH)2] secondary building unit (SBU) where the five zinc atoms are coplanar; its topological structure is an uninodal 10-connected network of (36.434.53.62) topology. The zinc ions in 1 have a coordination number varying from 4 to 6 and are accompanied by a variety of coordination geometries such as tetrahedral, trigonal bipyramidal, and octahedral. Compound 2 has a 3D architecture containing an unusual hexanuclear [Pb6(μ4-O)2] cluster unit composed of two edge-sharing oxygen-centred [Pb4(μ4-O)] tetrahedrons. One explanation for the presence of the centred bridging oxide ligands in 2 is that owing to steric constraints sufficient carboxylate ligands cannot coordinate to the Pb(II) centers to satisfy the positive charges of the Pb(II) cations. The Pb(II) ions in 2 exhibit diverse hemidirected coordination geometries with coordination numbers of 6 and 7. In the solid state, compounds 1 and 2 exhibit photoluminescence with emission maximum at 495 and 420 nm, respectively.

The Highly Connected MOFs Constructed from Nonanuclear and Trinuclear Lanthanide-Carboxylate Clusters: Selective Gas Adsorption and Luminescent pH Sensing

The highly odd-numbered 15-connected nonanuclear [Ln9(μ3-O)2(μ3-OH)12(O2C-)12(HCO2)3] and 9-connected trinuclear [Ln3(μ3-O)(O2C-)6(HCO2)3] lanthanide-carboxylate clusters with triangular and linear carboxylate bridging ligands were synergistically combined into Ln-MOFs, [(CH3)2NH2]3{[Ln9(μ3-O)2(μ3-OH)12(H2O)6][Ln3(μ3-O)(H2O)3](HCO2)3(BTB)6}·(solvent)x (abbreviated as JXNU-3, Ln = Gd, Tb, Er; BTB3- = benzene-1,3,5-tris(4-benzoate)), displaying a (3,9,15)-connected topological net. The JXNU-3(Tb) exhibits highly selective CO2 adsorption capacity over CH4 that resulted from the high localized charge density induced by the presence of the nonanuclear and trinuclear cluster units. In addition, JXNU-3(Tb) with high chemical stability and characteristic bright green color exhibits fluorescent pH sensing, which is pertinent to the different protonation levels of the carboxylate groups of the benzene-1,3,5-tris(4-benzoate) ligand with varying pH.

3D metal–organic frameworks constructed of 2D metal aromatic sulfonate–carboxylate layers and 1,3-di(4-pyridyl)propane pillars: syntheses, structural topologies, and luminescent properties

Two metal–organic frameworks {[Zn2(DSBDC)(dpp)2](H2O)2}n (1) (H4DSBDC = 2,5-disulfonylterephthalate acid and dpp = 1,3-di(4-pyridyl)propane) and [Cd2(SBTC)(dpp)1.5]n (2) (H4SBTC = 5-sulfonyl-1,2,4-benzenetricarboxylic acid) with novel sulfonate–carboxylate ligands have been synthesized and structurally characterized. The in situ formation of the H4DSBDC ligand derived from H4SBTC is unprecedented and involves a fundamentally new substitution of sulfonate for carboxylate in the in situ ligand synthesis reaction. The solid state structures of 1 and 2 consist of neutral 2D metal aromatic sulfonate–carboxylate layers, which are pillared by the dpp ligands to generate different 3D architectures. The topological structure of 1 is a trinodal net based on three kinds of topologically equivalent 4-connected nodes with the Schlafli symbol of (64.82). The framework of 2 can be classified as a 4,5,6-connected 3D net with the Schlafli symbol of (43.63) (43.65.82) (46.66.83). In the solid state, compounds 1 and 2 exhibit white-ish and blue photoluminescences, respectively.

Evolution from linear tetranuclear clusters into one-dimensional chains of Dy(III) single-molecule magnets with an enhanced energy barrier

Reactions of DyCl3·6H2O or Dy2O3 with 2-quinolinecarboxylic acid (H-QLC) yielded two compounds, namely, [Dy4(QLC)12(H2O)6]·4H2O (1) and [Dy(QLC)3(H2O)2]n (2). Compound 1 is a linear tetranuclear structure with one central [Dy2(QLC)4(H2O)4] subunit and two terminal [Dy(QLC)3(H2O)] subunits linked by bridging QLC− ligands. Compound 2 has a one-dimensional (1D) chain wherein the [Dy(QLC)2] unit formed by two QLC− ligands chelating a Dy(III) ion is connected by the bridging QLC− ligands. Compounds 1 and 2 exhibit slow magnetic relaxation behaviour in the absence of a static magnetic field, which is rarely observed in lanthanide-carboxylate compounds. During the structural evolution from a linear Dy4 cluster of 1 into a 1D chain of 2, the anisotropy energy barrier (Ueff) is enhanced from 45.4(2) to 144.2(1) K. Though the Dy(III) centers in 1 and 2 all are eight-coordinated with square antiprismatic coordination environments, the higher energy barrier observed for 2 could be the result of a more favorable crystal field for the Dy(III) ions in 2.

Dinuclear Lanthanide–Carboxylate Compounds: Field-Induced Slow Relaxation of Magnetization for Dysprosium(III) Analogue

Three chiral dinuclear lanthanide compounds, Ln(2)(mu(2)-L)(4)(L)(2)(phen)(2) (Ln=Dy (1), Gd (2), and Er (3); phen=1,10-phenanthroline), have been synthesized using the (S)-(+)-2-(6-methoxy-2-naphthyl)propionic acid (HL) ligand. The two lanthanide centres in compound Ln(2)(mu(2)-L)(4)(L)(2)(phen)(2) are bridged by four carboxylate groups to give a dinuclear Ln(2)(mu(2)-L)(4) core. The square antiprismatic coordination environment for each lanthanide centre is further completed by a chelating carboxylate group from another L- ligand and two nitrogen atoms from the phen ligand. A weak antiferromagnetic interaction between the two Gd-III ions is observed in compound 2. The Dy analogue displays field-induced slow magnetic relaxation behaviour with an effective energy barrier U-eff/k of 17.24(2) K and a pre-exponential factor (0) of 2.7(1)x10(-6)s. However, no slow relaxation phenomenon was observed for the Er derivative even in the presence of 2kOe applied field.

Urothermal synthesis of mononuclear lanthanide compounds: slow magnetization relaxation observed in Dy analogue

Two mononuclear compounds Ln(e-urea)8(NO3)3 (Ln = Dy(1) and Tb(2)) have been urothermally synthesized by using the ethyleneurea (e-urea) as an organic ligand and a solvent. The e-urea ligand with a single donor atom is a unique ligand for coordinating to lanthanide ions, which is very different from those commonly observed polytopic ligands with suitable coordination pockets to encapsulate lanthanide(III) ions or chelating organic ligands. The lanthanide center surrounded by eight e-urea ligands is in a square antiprismatic environment with an approximate D4d local symmetry. Magnetic properties of both compounds have been investigated in detail using direct-current and alternating-current susceptibility measurements. The Dy(1) analogue displays slow magnetic relaxation behavior with an effective energy barrier of the magnetic relaxation of 37.68 K and the pre-exponential factor τ0 of 1.47 × 10−9 s in the presence of direct-current field of 2 kOe.

New heterometallic frameworks with flexible sulfonate-carboxylate ligand: syntheses, structures, and properties

Solvothermal reactions of zinc acetate, sodium hydroxide, and sulfosuccinic acid (H3SSC) in alcohol/H2O, afforded two new three-dimensional (3D) heterometallic sulfonate-carboxylate frameworks, namely, [Na2Zn3(μ3-OH)2(SSC)2(H2O)4]n (1) and [Na4Zn(SSC)2(H2O)3.5]n (2). Compound 1 contains 2D anionic [Zn3(μ3-OH)2(SSC)2]2− layers based on the centrosymmetric mononuclear [Zn(SSC)2]4− units, while compound 2 has 2D anionic [NaZn(SSC)2]3− layers based on the [Zn2(SSC)2] macrocycle units. In both compounds, the 2D anionic layers are linked by sodium ions in various manners to generate quite different 3D architectures. Compounds 1 and 2 exhibit violet photoluminescences in the solid state. In addition, IR spectra, powder X-ray diffraction, elemental analysis, and thermogravimetric analysis of compounds 1 and 2 are also investigated.

Silver(I) and Lead(II) Halide Compounds with 4-Methyl-1,2,4-triazole-3-thiol

Four novel silver(i) and lead(ii) halide compounds with the 4-methyl-1,2,4-triazole-3-thiol (Hmptrz) ligand, namely [Ag2(mptrz)(μ3-X)]n (X = I (1) and Br (2)) and [Pb4(μ4-O)(mptrz)4(μ2-X)2] (X = I (3) and Cl (4)), have been synthesized and characterized. The structures exhibit different dimensionality depending on the nature of the metal ions. Compounds 1 and 2 are isomorphous and have 2D layered structures based on inorganic [Ag2X2]n infinite chains (X = I and Br), in which the mptrz– ligand displays a novel pentadentate bridging coordination mode. Compounds 3 and 4 have similar structures and are composed of a discrete tetranuclear lead(ii) cluster featuring an oxygen-centred Pb4(µ4-O) tetrahedron. Compounds 1 and 2 display solid-state photoluminescent emission with the maximum at 589 and 420 nm respectively. Compounds 3 and 4 show solid-state photoluminescent emission with the maximum at 710 and 540 nm respectively. Additionally, compounds 1–4 were characterized by IR, elemental analysis, powder X-ray diffraction and thermogravimetric analysis.