Lanthanide-Based Coordination Polymers for the Size-Selective Detection of Nitroaromatics

Isomorphous and isostructural lanthanide coordination polymers based on 2-(4-chlorobenzoyl)benzoic acid: Synthesis, structure, characterization, and luminescent properties

Two novel lanthanide (Nd, Gd) coordination polymers with chromate anion as building block of the 2D metal oxide

Eight new 2D isostructural lanthanide coordination polymers (Ln-CPs), [Ln(HL)(H2O)2(NO3)]·NO3 (1-Ln), Ln = NdIII, SmIII, EuIII, GdIII, TbIII, DyIII, HoIII, and YbIII ions, H2L = 4-(3,5-dicarboxylphenyl)-2-methylpyridine, were synthesized by using solvothermal methods and studied by structural analyses, magnetic analyses and luminescent probes. Crystallographic studies revealed that these compounds are 2D frameworks in which dinuclear units with double μ-syn,syn-carboxylate bridges are interlinked by single μ-trans,trans-carboxylate bridges from organic spacers. The layers are further stabilized and combined into 3D architectures through intra- and interlayer ππ stacking interactions and hydrogen bonding, respectively. Magnetic investigations indicated that the carboxylate bridges transmit intralayer antiferromagnetic coupling in 1-Nd, 1-Gd and 1-Ho but transmit intralayer ferromagnetic coupling in 1-Dy. Furthermore, 1-Dy also displays slow magnetic relaxation behavior with a high relaxation energy barrier (ΔUeff) of 100.7 K and a pre-exponential factor (τ0) of 1.4 × 10-8 s under zero dc field. The luminescence investigations showed that CPs 1-Eu and 1-Tb can serve as highly selective and recyclable sensing materials for Fe3+, Cr2O72- and nitrobenzene. Thus, both 1-Eu and 1-Tb should be excellent candidates for multifunctional sensors.

Three series of lanthanide coordination polymers of {[Ln2(HIDC)2(SO4)(H2O)5]·H2O}n (CPs-1Ln, Ln = Sm, Eu, Tb, Dy, Ho, Er, and Yb), {(H2prz)[Ln2(HIDC)2(SO4)2]}n (CPs-2Ln, Ln = Sm and Eu), and [Ln2(HIDC)2(SO4)(H2O)2]n (CPs-3Ln, Ln = Tb, Dy, Ho, Er, and Yb) have been hydrothermally synthesized by the reactions of Ln(NO3)3·6H2O with imidazole-4,5-dicarboxylic acid (H3IDC) and sulfuric acid (H2SO4) in the presence of piperazine (prz) at different temperatures. The results of the single-crystal X-ray diffraction analysis reveal that CPs-1Ln presents a three-dimensional (3D) architecture, in which alternating one-dimensional (1D) right-/left-handed helical chains of [Ln2(HIDC)2]∞ are interlinked by μ3-SO42– anions. CPs-2Ln assumes a H2prz2+ templated 3D anionic layer-pillared metal–organic framework (MOF) of {[Ln2(HIDC)2(SO4)2]}n2n–, in which two-dimensional (2D) (6,3) network layers of [Ln2(HIDC)2]n2n+ are pillared by μ2-SO42– anions. CPs-3Ln is a 2D layer structure, in which two 2D (6,3) monolayers of [Ln2(HIDC)2(H2O)2]n2n+ are connected by μ2-SO42– anions to form a 2D double-layer structure. The adjacent 2D double-layers are further stacked together via strong hydrogen bonding interactions to generate a 3D supramolecular framework. In addition, the results of photoluminescent measurements for Sm (1Sm and 2Sm), Eu (1Eu and 2Eu), Tb (1Tb and 3Tb), and Dy (1Dy and 3Dy) compounds in the solid state at room temperature indicate that different structural types have a different influence on their characteristic photoluminescences.

Two new PbII metal‐organic coordination polymers [Pb(3‐pdip)(glu)]·H2O (1) and [Pb(3‐pdip)2(odc)]·2H2O (2) [3‐pdip = 2‐(3‐pyridine)imidazo[4,5‐f]1,10‐ phenanthroline, H2glu = glutaric acid, H2odc = octanedioic acid], were synthesized by hydrothermal reactions of varying fatty acid ligands, and structurally characterized by single‐crystal X‐ray diffraction. Complex 1 exhibits a one dimensional (1D) chain structure, in which 3‐pdip ligands are attached to one side of the 1D chain. Complex 2 exhibits also a 1D chain structure, in which some paired 3‐pdip ligands are affiliated on both sides of the 1D chain. In the title complexes, the π–π stacking and hydrogen‐bonding interactions extend the 1D chain into a 3D supramolecular framework, respectively. The structural differences between the title complexes indicate the importance of fatty acid length for the creation of molecular architectures. Moreover, the thermal and fluorescence properties of title complexes are also reported.

The synergistic optical, electronic, and chemical properties of metal nanoparticles present in close proximity have potential applications in energy, medicine, and sustainability. Fundamental studies and application development based on spontaneous self-assembly of one-dimensional (1D) chains of metal nanoparticles without external organization agencies have been pursued for over four decades. The spontaneous formation of 1D chains in a solution of stabilized spherical nanoparticles may be driven by the emergence of local anisotropy due to dipolar interaction, representing a trapped non-equilibrium state. Here, the kinetics of this broken symmetry in the "directed" self-assembly of spherical particles is studied to form a 1D chain. The 1D chain assembly of 10 nm Au particles that had been stabilized by electrostatic repulsion is initiated by adding a small amount of divalent cation salt. A phenomenological model is presented to explain the transition state controlling the kinetics of the 1D self-assembly. Experimental and simulation studies were combined to measure the kinetics of the chain growth over time which revealed a sharp transition between two growth processes that were analogous to addition and condensation polymerization.

Three new coordination polymers, namely, {[Cu2(bcpmba)(μ4-OH)]·2H2O}n (1), [Mn(Hbcpmba)]n (2), and [Co2(bcpmba)(μ3-OH)·H2O]n (3) (H3bcpmba = 3,5-bi(4-carboxy-phenylene-methylene-oxy)-benzoic acid) have been prepared under solvothermal conditions. The complexes were characterized by physico-chemical and spectroscopic methods. All of the compounds 1–3 contain one-dimensional (1D) chains extended via the bcpmba3− bridge to generate 2D porous layers which are further connected by bcpmba3− ligands to form 3D porous coordination polymers. The result shows configurations of the ligand have an important influence on the structure. Magnetic susceptibility measurements indicate that compounds 1–3 exhibit antiferromagnetic coupling between adjacent metal ions, with the corresponding J value of − 2.76 cm−1 for compound 2. Three porous coordination polymers, namely, {[Cu2(bcpmba)(μ4-OH)]·2H2O}n (1), [Mn(Hbcpmba)]n (2) and [Co2(bcpmba)(μ3-OH)·H2O]n (3) have been synthesized by employing a semi-rigid aromatic multicarboxylate acid (3,5-bi(4-carboxy-phenylene-methylene-oxy)-benzoic acid, H3bcpmba) under solvothermal conditions. Porous coordination polymers 1–3 consisted of 1D chain extended via the bridge of bcpmba3– to generate 2D porous layers and further connected by bcpmba3– to provide a 3D porous frameworks. The results reveal that different coordination modes of the ligand play an important role in the self-assembly processes to form metal-organic frameworks with different structures. Moreover, compounds 1–3 exhibited antiferromagnetic properties.

Abstract. Two bis‐triazole‐bis‐amide‐based copper(II) pyridine‐2,3‐dicarboxylate coordination polymers (CPs), [Cu(2,3‐pydc)(dtb)0.5(DMF)]·2H2O (1) and [Cu(2,3‐pydc)(dth)0.5(DMF)]·2H2O (2) (2,3‐H2pydc = pyridine‐2,3‐dicarboxylic acid, dtb = N,N′‐bis(4H‐1,2,4‐triazole)butanamide, and dth = N,N′‐bis(4H‐1,2,4‐triazole)hexanamide), were synthesized under solvothermal conditions. CPs 1 and 2 show similar two‐dimensional (2D) structures. In 1, the 2,3‐pydc anions bridge the CuII ions into a one‐dimensional (1D) chain. Such 1D chains are linked by the dtb ligands to form a 2D layer. The adjacent 2D layers are extended into a three‐dimensional (3D) supramolecular architecture by hydrogen‐bonding interactions. The electrochemical properties of 1 and 2 were investigated.

Four new metal coordination polymers, [Cd(pybma)2]n (1), [Zn(pybma)(C2O4)0.5·0.5H2O]n (2), [Co(pybma)(C2O4)0.5]n (3), and [Zn3(pybma)2(HBTC)2(H2O)4]n (4) [pybma = 2-(2-pyridinyl-benzimidazolyl) acetic anion; H3BTC =1,3,5-benzenetricarboxylate], have been synthesized under hydrothermal conditions and structurally characterized by element analyses, IR spectroscopy, and single-crystal X-ray diffraction analyses. 1 has a one-dimensional (1D) chain structure, which contains two kinds of rings. Interestingly, 2 has a two-dimensional (2D) metal−organic framework and can be seen as the unity of two parallel double-stranded helices, in which the helices are bridged by oxalate ligands. 3 has a 2D framework built from 1D chains and ox bridges. 4 has 2D layer framework which is assembled into a three-dimensional (3D) framework with two kinds of channels. Polymers 1, 2, and 4 exhibit obvious fluorescent emissions in the solid state at room temperature; no fluorescent emission is observed in polymer 3.

Two novel hydroxide anions bridged lanthanide coordination polymers based on fluorinated carboxylate ligand: Structures, luminescence and magnetic property

A series of three-dimensional (3D) novel coordination polymers M(bpdc)1.5(H2O) x 0.5DMF (M = Tb (1), Ho (2), Er (3), or Y (4)) have been synthesized by reaction of the rare earth ions (M3+) with 4,4'-biphenyldicarboxylic acid (H2bpdc) in a mixed solution of DMF and C2H5OH. They possess the same 3D architectures and crystallize in monoclinic space group C2/c. Two seven-coordinated metal centers and four dimonodentate bpdc groups construct a paddle-wheel building block. These building blocks connect with two carboxyl groups to lead to a one-dimensional inorganic chain, ---M-O-C-O-M---, along the [001] direction. The inorganic chains are linked with two biphenyl groups to form 25.15 A x 17.09 A rhombic channels along the c axis without interpenetration. These complexes exhibit strong fluorescence in the visible region, and complex 3 shows Er3+ characteristic emission in the range of 1450-1650 nm at room temperature. These complexes could be anticipated as potential fluorescent probes and an IR-emitter, respectively.

Two polymorphic structures of Form II and Form III of agomelatine were determined by single and powder X-ray diffraction, respectively, in which the agomelatine molecules are linked through the intermolecular hydrogen bonding interactions to form a one-dimensional (1D) chain, and the 1D chains are further packed through interchain π···π and C−H···π interactions to generate the three-dimensional (3D) structures. Two agomelatine cocrystals with acetic acid (1) and ethylene glycol (2) were synthesized, and their structures were determined by single and powder X-ray diffraction, respectively, in which the acetic acid molecules in 1 alternately link the agomelatine molecules to form 1D right-handed and left-handed helical chains, while the alternately linking of agomelatine molecules by ethylene glycol molecules in 2 generates the homochiral right-handed helical chains. After the formation of cocrystals of 1 and 2, the melting points dramatically decrease, and the solubility is approximately twice as large as ...

A novel zinc complex formulated as [Zn(Bript)(bpa)(H2O)]n (1) (H2Bript = 4-bromoisophthalic acid, bpa = 1,2-bi(4-pyridyl)ethane) has been synthesized through hydrothermal reaction. It was structurally characterized by elemental analysis and x-ray single-crystal diffraction. The x-ray crystal structure shows that the complex belongs to monoclinic systems, P21/n space group, and a = 10.997(6) Å, b = 14.578(8) Å, c = 12.963(7) Å, β = 105.993(6)°. The adjacent Zn atoms are bridged by Bript to form a one-dimensional (1D) chain. Such 1D chains are further connected by hydrogen bonding to generate a three-dimensional (3D) supramolecular network. Fluorescence measurements show that 1 has medium fluorescent emissions at 404 nm and 468 nm upon excitation at 288 nm.

Selectively sensing and adsorption properties of nickel(II) and cadmium(II) architectures with rigid 1H-imidazol-4-yl containing ligands and 1,3,5-tri(4-carboxyphenyl)benzene

A new family of coordination polymers, [Cu(btm)2(ClO4)2]n (1, btm = 1,2-bis(1,2,4-triazol-1-yl)methane), {[Cu(bte)2(ClO4)(H2O)](ClO4)(H2O)2}n (2, bte = 1,2-bis(1,2,4-triazol-1-yl)ethane), {[Cu(btp)2(H2O)2](ClO4)2(H2O)1.5}n (3, btp = 1,3-bis(1,2,4-triazol-1-yl)propane) and {[Cu(btb)2(H2O)2](ClO4)2}n (4, btb = 1,4-bis(1,2,4-triazol-1-yl)butane) have been prepared under hydrothermal conditions and characterized by elemental analyses, IR, thermogravimetric and X-ray structural analyses. The bis(triazole) ligands with different spacer lengths exhibit conformational flexibility and lead to the generation of diversified architectures. 1 and 2 show as one-dimensional (1D) chains. 3 shows as two-dimensional (2D) rectangular networks with a (4,4) topology, which contain 2D planar nanogrid networks stacked in a step stacking fashion. Weak O⋯H–C and N⋯H–C hydrogen bonds reside among these 2D layers, which link the 2D layers to lead to a 3D supramolecular architecture. 4 is a 3D MOF with large 1D rhombic channels with dimensionalities of 14.16 × 10.92 Å2 accommodating ClO4− anions, which has a 3D diadiamond network with one point, {66}. Their EPR spectra have also been investigated in the solid state.