Hydrothermal Syntheses,Crystal Structure and Luminescent Properties of Two New Zn(II) Coordination Polymers

Two new zinc(II) coordination polymers; namely, [Zn(BDC)(L)_0.5]_n (1) and {[Zn(BDC)(L)]·3H₂O}(2), were successfully synthesized by the assembly of Zn(II) ion, 1.2-benzene-dicarboxylate acid (H₂BDC) and 1,4-bis(2-methylimidazole-3-ium-1-yl) biphenyl (L). A change in the pH values resulted in complexes with different compositions and dimensionalities. Formed at the lower pH, 1 exhibits a three-dimensional structure with mab topology. At a higher pH, 2 shows a two-dimensional structure, which contains one-dimensional helical chains. The luminescent properties for 1 and 2 were investigated in the solid state at room temperature.     

Synthesis,Crystal Structures and Fluorescent Properties of Two Bimetallic Coordination Polymers

Two novel 2D and 3D bimetallic Cd^IINi^II coordination polymers, Cd(2Mpz)(H₂O)Ni(CN)₄ (I) (2Mpz: 2-methylpyrazine) and Cd(2Epz)(H₂O)Ni(CN)₄ (II) (2Epz: 2-ethylpyrazine), have been synthesized and characterized by elemental analysis, powder X-ray diffraction, IR spectra, fluorescent spectra, single crystal X-ray diffraction and thermogravimetric analysis. Based on the analysis of structures, it can be found that the Cd(II) ions in the two complexes have the similar octahedral coordination geometry of CdN₅O, which are linked by [Ni(CN)₄]²⁻ units at the equatorial plane to form 2D sheet layers [CdNi(CN)₄] _n . However, it’s noted that the coordination environment of Ni(II) ions and action of ligands are different. All the Ni(II) ions in I are the five-coordinated pentahedron configuration and 2-methylpyrazine acts as a bridging ligand linking the Cd(II) and Ni(II) ions of the adjacent layers, leading to the 3D metal–organic framework. The structure of II indicates all the Ni(II) ions are the four-coordinated square plane and 2-ethylpyrazine is a terminal ligand coordinated to Cd(II) ions, forming the 2D layer structure. Moreover, the two complexes display significant thermal stability and fluorescent properties.     

Synthesis, Crystal Structures and Fluorescence Properties of Two One-Dimensional Cadmium(II) Coordination Polymers Containing Flexible Bis(benzimidazole) Ligands

Two one-dimensional Cd(II) coordination polymers constructed by ribbon-like molecules, {[Cd(L₁)₂(NO₃)]·NO₃} _n (1) (L₁ = 1,3-bis(5,6-dimethylbenzimidazol-1-yl)benzene) and [Cd(L₂)₂(NO₃)₂] _n (2) (L₂ = 1,3-bis(benzimidazol-1-yl)benzene) have been obtained through assembly of the two structurally similar flexible bis(benzimidazole)-based ligands and cadmium nitrate tetrahydrate. The cadmium(II) centers display different coordination environments with trigonal-bipyramidal geometry in 1, and a octahedral geometry in 2. Weak C–H···O interactions in 1 result in a two-dimensional supramolecular layer; two π–π interactions are present in 2 forming a three-dimensional supramolecular network structure. The solid state fluorescence properties of 1 and 2 were investigated.     

Hydrothermal Synthesis, Crystal Structures and Photoluminescent Properties of Two New Co(II) Coordination Polymers Derived from Dicarboxylate and N-Donor Ligands

Two new Co(II) coordination polymers with 5-position substituted 1,3-benzenedicarboxylate and N-donor auxiliary ligands, [Co(5-OH-ip)(L₁)_1.5(H₂O)]_n (1) and [Co(5-NO₂-ip)(L₂)_1.5]_n (2) (5-OH-ip = 5-hydroxyisophthalic acid, 5-NO₂-ip = nitroisophthalic acid, L₁ = 1,4-bis(imidazol-1-yl) benzene and L₂ = 1,4-bis(1-imidazol-yl)-2,5-dimethyl benzene), were synthesized by hydrothermal reactions. Complex 1 shows a 3-fold interpenetrating 3D framework with the topological symbol of (4⁴·6⁶). Complex 2 exhibits a 3D framework with the vertex symbol of (4²·6⁸). Furthermore the luminescent properties of 1 and 2 were investigated.     

Synthesis,Crystal Structure and Luminescent Property of a New Zn(II) Coordination Polymer with Twofold Interpenetrated pcu Topology

A new Zn(II) coordination polymer; namely, [Zn(FA)(bmix)_0.5] _n ·nH₂O (1, H₂FA = fumaric acid, bmix = 1,4-bis(2-methyl-1H-imidazol-1-ylmethyl)benzene) was synthesized with fumaric acid and flexible 2-methylimidazole-based ligands with Zn(II) salts under hydrothermal conditions. Single-crystal X-ray diffraction reveals that 1 features a twofold interpenetrating three-dimensional pillar-layered framework based on paddle-wheel shaped [Zn₂(COO)₄] subunits. The structure may be simplified to a 6-connected pcu topological network. Luminescent investigation reveals that 1 exhibits intense ligand-centered fluorescence at room temperature.     

Four New Ag(I) Coordination Polymers: Synthesis, Crystal Structures and Thermal Stability

Four silver(I) coordination polymers of composition [Ag₆(bptp)₃(OOCCF₂CF₂COO)₃]_∞ (1), [Ag₅(bptp)₂(CF₃SO₃)₅(CH₃COCH₃)₂]_∞ (2), [Ag(bmtm)(C₁₀H₇SO₃)]_∞ (3), and [Ag₁₀(bpte)₄(NO₃)₁₀]_∞ (4) (bmtm = bis(methylthio)methane, bpte = 1,2-bis(phenylthio)ethane, bptp = 1,3-bis(phenylthio)propane) have been synthesized and structurally characterized. The 2D-coordination networks of both 1 and 2 consist of two meshed networks, (Ag-anion)_∞ and (Ag-ligand)_∞, which share their silver atoms. The 1D-coordination polymers of 3 are associated through weak van der Waals interactions into 2D network while polymer 4 forms a tubular structure. Relatively short Ag···Ag interactions are found in both 1 and 3. The stoichiometries of the obtained polymers were found to be independent of the starting materials metal-to-ligand ratio except for coordination polymer 4. Thermogravimetric analyses of 1 and 2 revealed that they decompose in a single step to metallic silver while 3 and 4 showed a two-step weight loss.     

Syntheses, Structures, and Luminescent Properties of Two Novel Coordination Polymers with Mixed Ligands

Two novel metal–organic coordination polymers {[Pb₂(MIP)₂(BDC)₂]·H₂O} _n 1 and [Cd(MIP)(NDC)] _n 2 [MIP = 2-(3-methoxyphenyl)-1H-imidazo [4,5-f] [1, 10] phenanthroline, BDC = terephthalic acid, NDC = naphthalene-1,4-dicarboxylic acid] were obtained from hydrothermal reaction and characterized by elemental analysis, thermogravimetric (TG) analysis, infrared spectrum (IR) and single-crystal X-ray diffraction. The coordination polymers crystallize in triclinic, space group P-1 with a = 1.0335(2), b = 1.4224(3), c = 1.8156(4) nm, β = 106.088(3)° for complex 1 and the complex 2 crystallizes in monoclinic, space group P2(1)/n with a = 1.2562(8), b = 1.4800(9), c = 1.3723(8) nm, β = 97.257(1)°, respectively. The metal ions Pb(II) are located in [:PbN2O4] pentagonal bipyramidal geometry in complex 1. The metal ions Cd(II) in complex 2 act as distorted octahedral geometry, being surrounded by four carboxylate oxygen atoms from three NDC ligands and two donor nitrogen atoms from one MIP molecule. Moreover, there are hydrogen bonds in the two complexes, and it is noteworthy that the existence of hydrogen bonds and π–π interactions reinforce the structural stability of the title complexes, which have been proved by TG analysis. The luminescent properties for the ligand MIP, NDC and complex 2 are also discussed in detail.     

Two New Zn(II) Coordination Polymers Constructed from Asymmetric Biphenyl-Dicarboxylate and Imidazole-Containing Ligands: Structures and Photoluminescent Properties

Two new coordination polymers, [Zn(2,4′-bpdc) (L₁)_0.5·(H₂O)] _n (1) and {[Zn(3,4′-bpdc) (L₁)]·(H₂O)} _n (2), have been obtained from hydrothermal reactions of zinc (II) nitrate with the ligands 1,4-bis(imidazol-1-yl)benzene (L) and two asymmetric biphenyl-dicarboxylate [biphenyl-2,4′-dicarboxylate (2,4′-bpdc) and biphenyl-3,4′-dicarboxylate (3,4′-bpdc)]. Single-crystal X-ray diffraction analysis the two coordination polymer show different structures due to the different dicarboxylate ligands. Complex 1 features a 3D mab topological net. Complex 2 is unusual case that has 3D frameworks constructed from 2D 4⁴-sql layers by parallel polycatenation. The photoluminescent properties of 1 and 2 have also been investigated.     

Synthesis and Crystal Structure of Three New Zn(II), Ni(II) and Mn(II) Coordination Polymers Based on Asymmetric Dicarboxylate Ligand

Three new coordination polymers [Zn(pda)(H₂O)]_n (1), [Ni(pda)(bib)_1.5]_n (2) and [Mn₂(pda)₂(bimb)]_n (3) [H₂pda?=?3,4′-biphenyl-dicarboxylic acid, bib?=?4,4′-bis (2-imidazol-1-ylmethyl) biphenyl and bmib?=?4,4′-bis (2-methylimidazol-1-ylmethyl)biphenyl] have been synthesized and structurally characterized by elemental analysis, IR and X-ray diffraction. Single-crystal X-ray analyses revealed that that pda ligand acts as bridging ligand, exhibiting rich coordination modes to link metal ions: monodentate, bidentate chelating, bis-monodentate and chelating/bridging fashions. Compound 1 and 2 demonstrate a one-dimensional chain. Compound 3 is a two-dimensional (4,4) layer structure. Furthermore, the solid state luminescence spectrum of compound 1 is investigated at room temperature.     

Synthesis,Structures, and Catalytic Properties of Two Zinc(II) Coordination Polymers Constructed from Polycarboxylate and Bis(Benzimidazole) Ligands

Two Zn(II) coordination polymers, formulated as {[Zn(L1)_0.5(btc)_0.5(H₂O)]·H₂O} _n (1) and {[Zn(L2)(1,4-ndc)]·2H₂O} _n (2) [L1 = 1,4-bis(2-methylbenzimidazole-1-ylmethyl)benzene, L2 = 1,4-bis(2-methylbenzimidazole)butane, H₄btc = butane-1,2,3,4-tetracarboxylic acid, 1,4-H₂ndc = 1,4-naphthalenedicarboxylic acid] have been synthesized and structurally characterized by single crystal X-ray diffraction. Complex 1 features a 3D (3,4)-connected network with the topology of fsh-3,4-P2₁/c. Complex 2 is a 2D (4,4) grid with sql topology and further extends into a 3D supramolecular framework by π–π stacking interactions. In addition, the thermal stability, fluorescence, and catalytic properties of two complexes for degrading methyl orange dye in a Fenton-like process were investigated.     

Imidazole-Containing Ligands Assisted Self Assembly of Two New Cd(II) Coordination Polymers: Syntheses, Crystal Structures and Photoluminescent Properties

Two new coordination polymers, {[Cd₂(PDC)₂(H₂O)₂(L₁)]·2H₂O}_n (1) and {[Cd (2,5-PDC)(H₂O)(L₂)]·H₂O}_n (2), have been obtained from hydrothermal reactions of Cd²⁺ ion with the 2,5-pyridinedicarboxylic acid (H₂PDC) and two imidazole-containing ligands [L₁ = 1,4-bis(imidazol-1-yl)benzene and L₂ = 1,4-bis(1-imidazol-yl)-2,5-dimethylbenzene]. Complex 1 features a three-dimensional 6-connected rob topological net. Complex 2 shows a two-dimensional 6-connected hxl topological net. The structural differences between 1 and 2 demonstrate that the different imidazole-containing ligands play critical roles in the formation of the resulting frameworks. The photoluminescent properties of 1 and 2 have also been investigated.     

Syntheses, Structures, and Luminescent Properties of Two Novel Coordination Polymers with Poly-Carboxylate and N-Heterocyclic Ligands

Two novel metal–organic coordination polymers {[Pb(CIPT)(1,4-BDC)]·2H₂O} _n 1 and {[Zn₂(IPDT)₂(1,4-BDC)₂(H₂O)].3H₂O} _n 2 [CIPT = 2-(3-chlorophenyl)-1H-imidazo[4,5-f][1,10]phenanthroline, 1,4-BDC = terephthalic acid, IPDT = 4-(1H-imidazo[4,5-f][1,10]phenanthroline-2-yl)-2,6-dimethoxyphenol] were obtained from hydrothermal reaction and characterized by elemental analysis, thermogravimetric (TG) analysis, IR and single-crystal X-ray diffraction. Both of the two coordination polymers exhibit one-dimensional (1D) infinite chain structures through non-covalent interactions, and the existence of hydrogen bonds interactions lead the 1D chain to 2D layer structures. It is noteworthy that the existence of hydrogen bonds reinforces the structural stability of the complexes 1 and 2, which can be proved by TG analysis. The photoluminescent study of coordination polymer 1 shows that it exhibits fluorescent emission band at 637 nm, which is red-shifted by 46 nm relative to the free ligand CIPT.