Syntheses,crystal structures,and optical properties of a series of transition metal coordination polymers with chelidamic acid and 4,4′-bipyridine

A series of transition metal (Zn, Cu, Mn) complexes with chelidamic acid (2,6-dicarboxy-4-hydroxypyridine, H₃CAM) and 4,4′-bipyridine (bipy), [Zn₂(bipy)Cl₂] _n (1), {[Zn₂(HCAM)(H₂CAM)₂]?·?(bipy)?·?3.5H₂O} _n (2), [Mn₃(HCAM)₃(H₂O)₇]?·?(bipy)?·?3H₂O (3), [Mn₂(HCAM)₂(bipy)?·?(H₂O)₂]?·?4H₂O (4), [Cu₂(HCAM)₂(bipy)?·?(H₂O)₂]?·?4H₂O (5), and Cu₂(HCAM)₂(bipy)?·?(H₂O)₂ (6), have been synthesized by hydrothermal or solution methods and characterized by single-crystal X-ray diffraction. The structural analyses reveal that 1 exhibits a zigzag chain of Zn(II), Cl^?, and 4,4′-bipyridine. In 2, a 1-D polymeric [Zn₂(HCAM)(H₂CAM)₂] _n chain and a discrete 4,4′-bipyridine assemble into a 2-D supramolecular network via H-bonds. Complex 3 consists of asymmetric units of Mn₃(HCAM)₃(H₂O)₇ that are linked by hydrogen bonds to form a 2-D H-bonded network. Complexes 4–6 are isomorphous and possess discrete structures. The photoluminescent properties of 1–6 at room temperature were studied.     

Syntheses and characterization of four coordination compounds derived from 10,11,12,13-tetrahydro-4,5,9,14-tetraaza-benzo[b]triphenylene and benzene-dicarboxylic acids

[Co₂(TTBT)₄(1,2-BDC)₂] _n ?·?4nH₂O (1), [Pb₂(TTBT)₂(1,3-BDC)₂] _n ?·?nTTBT?·?2nH₂O (2), [Fe(TTBT)(1,4-BDC)(H₂O)] _n (3), and [Zn(TTBT)(1,4-BDC)(H₂O)] _n (4) have been hydrothermally synthesized by self-assembly of TTBT (TTBT?=?10,11,12,13-tetrahydro-4,5,9,14-tetraaza-benzo[b]triphenylene), benzene-dicarboxylic acid ligands 1,2-H₂BDC, 1,3-H₂BDC or 1,4-H₂BDC (1,2-H₂BDC?=?1,2-benzenedicarboxylic acid, 1,3-H₂BDC?=?1,3-benzenedicarboxylic acid, 1,4-H₂BDC?=?1,4-benzenedicarboxylic acid), and various metal salts. Compound 1 has dinuclear cluster units, four dimeric Co₂ units connected to form a 32-membered ring via weak offset π–π interactions, which are further stacked via strong π–π interactions to form a 3-D supramolecular framework. Complex 2 contains 2-D layers with rhombohedral grids, which are connected to a 3-D structure by π–π interactions. 3 and 4 feature 1-D infinite chains, which are further extended by strong π–π interactions and O–H···O hydrogen bonds resulting in 3-D supramolecular architectures. The photoluminescent properties of 2 and 4 have also been investigated.     

Three new coordination frameworks based on 2-ethyl-imidazole-4,5-dicarboxylate and 1,10-phenanthroline: syntheses,crystal structures,and luminescence

Three new coordination polymers based on 2-ethyl-imidazole-4,5-dicarboxylate with 1,10-phenanthroline as ligands, Pb(HEIDC)(phen)₂ (1), [Zn(EIDC)(phen)] _n (2), and {[Ba(H₂EIDC)₂(phen)]?·?(phen)₂?·?[Ba(H₂EIDC)(HEIDC)(phen)]} _n (3) (H₃EIDC?=?2-ethyl-1-Himidazole-4,5-dicarboxylate; phen?=?1,10-phenanthroline), have been synthesized under hydrothermal conditions and characterized by elemental analysis, infrared spectroscopy, thermogravimetric analysis, and single-crystal X-ray diffraction. Complex 1 displays a tetranuclear square constructed of four Pb(II) centers, four HEIDC, and eight phen, resulting in a 3-D network with a 1-D open channel along the c-axis via C–H?···?O hydrogen bonds, C–H?···?π, and π–π stacking interactions. Complex 2 is an infinite zigzag chain resulting in the final 3-D supramolecular framework via C–H?···?O and π–π stacking interactions. Complex 3 is composed of two individual Ba chains, exhibiting a 3-D framework via O–H?···?O, O–H?···?N hydrogen bonds, and π–π stacking interactions. The photoluminescence spectra of 1 and 2 in the solid state have been investigated, 1 exhibits green photoluminescence in the solid state at room temperature.     

Syntheses,crystal structures,and catalytic activities of three new Cu(II) coordination polymers based on 2-(1H-1,2,4-triazole)-1-acetic acid

Three new coordination polymers, {[Cu(trza)(2,2′-bipy)(H₂O)]?·?(ClO₄)} _n (1), {[Cu(trza)(2,2′-bipy)(H₂O)]?·?(BF₄)} _n (2), and {[Cu(trza)(4,4′-bipy)]?·?(H₂O)?·?(ClO₄)} _n (3) (Htrza?=?2-(1H-1,2,4-triazole)-1-acetic acid), have been synthesized and characterized by single-crystal X-ray diffraction analysis. Both 1 and 2 exhibit 1-D chain structure while 3 displays 2-D layer structure. The catalytic activities of 1 and 3 in the green oxidative coupling of 2,6-dimethylphenol have been investigated.     

Syntheses,structures, and magnetism of two coordination compounds with 3,3′,4,4′-biphenyltetracarboxylic acid and 1,10-phenanthroline

Two coordination polymers, {[Mn(1,10-phen)₂(3,4-H₂bptc)]?·?(H₂O)}_{2 n} (1) and {[Co₂(1,10-phen)(3,4-bptc)(H₂O)₂]?·?H₂O} _n (2) (3,4-H₄bptc = 3,3′,4,4′-biphenyltetracarboxylic acid, 1,10-phen?=?1,10-phenanthroline), have been prepared and structurally characterized. In both compounds, 3,4-H₂bptc^2– and 3,4-bptc^4? exhibit different coordination modes and lead to various architectures. Compound 1 displays 1-D zigzag chains constructed with hydrogen bonds. Compound 2 exhibits a 2-D layer constructed from bpta^4? between the dinuclear Co(II) units. The thermal stabilities and magnetic properties are also reported. In addition, 1 was explored as a luminescent material. The carboxylic oxygen atoms act as H-bond acceptors and donors forming a 1-D ladder-like arrangement.     

Four Zn(II)/Cd(II) coordination polymers derived from isomeric benzenedicarboxylates and 1,6-bis(triazol)hexane ligand: synthesis,crystal structure,and luminescent properties

Four coordination polymers, [Zn(o-bdc)(bth)_0.5(H₂O)] _n (1), [Cd(o-bdc)(bth)_0.5(H₂O)] _n (2), [Zn(m-bdc)(bth)] _n (3), and [Cd(p-bdc)(bth)?·?(H₂O)₂] _n (4) (where o-bdc?=?1,2-benzenedicarboxylate, m-bdc?=?1,3-benzenedicarboxylate, p-bdc?=?1,4-benzenedicarboxylate, and bth?=?1,6-bis(triazol)hexane), have been hydrothermally synthesized and structurally characterized. Both 1 and 2 are isostructural, featuring two binodal architectures: (6³)(6⁵·8) topology in terms of o-bdc and Zn^II/Cd^II as three- and four-connected nodes. Complex 3 shows a 2-D (4,4) network with the Zn?···?Zn?···?Zn angle of 57.84°, whereas 4 exhibits planar 2-D (4,4) network. These 2-D networks of 3 and 4 are extended by supramolecular interactions, such as CH?···?π/π–π stacking and hydrogen-bonding into 3-D architecture. A structural comparison of these complexes demonstrates that the dicarboxylate building blocks with different dispositions of the carboxyl site play a key role in governing the coordination motifs as well as 3-D supramolecular lattices. Solid-state properties such as photoluminescence and thermal stabilities of 1–4 have also been studied.     

Supramolecular networks constructed by cationic copper(II) complexes incorporating hybrid water–anionic polymeric assemblies

Two complexes, [Cu₂(TFSA)(2,2′-bpy)₄]?·?TFSA?·?8H₂O (1) and {[Cu(4,4′-bpy)(H₂O)₂]?·?TFSA?·?6H₂O} _n (2) (H₂TFSA?=?tetrafluorosuccinic acid, 2,2′-bpy?=?2,2′-bipyridine, and 4,4′-bpy?=?4,4′-bipyridine), have been synthesized and structurally characterized by X-ray structural analyses. Complex 1 is a binuclear molecule bridged by TFSA ligands; 2 is a 1-D chain bridged by 4,4′-bpy ligands. The asymmetric units of the two complexes are composed of cationic complexes [Cu₂(TFSA)(2,2′-bpy)₄]²⁺ (1) and [Cu(4,4′-bpy)(H₂O)₂]²⁺ (2), free TFSA anion, and independent crystallization water molecules. A unique 2-D hybrid water–TFSA anionic layer by linkage of {[(H₂O)₈(TFSA)]^2?} _n fragments consisting of 1-D T6(0)A2 water tape and TFSA anionic units by hydrogen bonds in 1 was observed. Unique 2-D hybrid water–TFSA anionic layer generated by the linkage of {[(H₂O)₆(TFSA)]^2?} _n fragments consisting of cyclic water tetramers with appended water molecules and TFSA anionic units, and 1-D metal–water tape [Cu–H₂O?···?(H₂O)₆?···?H₂O^?] _n in 2 were found. 3-D supramolecular networks of the two complexes consist of cationic complexes and water–TFSA anionic assemblies connected by hydrogen bonds.     

Synthesis,structures, and properties of lead(II) and cobalt(II) metal-organic frameworks based on a flexible benzophenone-2,4′-dicarboxylic acid (H2bpdc)

Two new coordination polymers, [Pb(bpdc)] _n (1) and [Co(bpdc)(phen)] _n (2) [H₂bpdc?=?benzophenone-2,4′-dicarboxylic acid, phen?=?1,10-phenanthroline], have been synthesized and structurally characterized. Hydrogen bonding and π?···?π stacking extend 1 and 2 into 3-D supramolecular architectures, where 1 exhibits a 3-D framework with 1-D hairpin-like helicates based on Pb–O covalent bonds and 2 displays a 3-D network with 1-D zipper-like chains based on Co–O and Co–N covalent bonds. The FT-IR spectra, PXRD and TG analyses are discussed for 1 and 2. Fluorescence spectra and luminescent lifetime are studied for 1.     

Formation of a 1-D metal–water chain and a 2-D water–sulfate layer containing cyclic water octamers in a 3-D supramolecular network

A new tetranuclear complex, {[Cu(phen)(OH)]₄(H₂O)₂}?·?(SO₄)₂?·?8H₂O (1) (phen = 1,10-phenanthroline), has been synthesized and characterized by elemental analysis, UV-Vis, IR, TG, and single-crystal X-ray diffraction. Complex 1 exhibits a 3-D supramolecular network with a 1-D metal–water chain consisting of tetranuclear hydroxo-bridged copper(II) clusters and water octamers and a 2-D water–sulfate layer containing cyclic water octamers with five types of O–H?···?O hydrogen-bonding motifs. The free ligand and its complex were screened for antibacterial activity against Gram-positive and Gram-negative bacteria.     

Syntheses and crystal structures of two Co(II) coordination polymers based on 4,6-bis(4-methylbenzoyl)isophthalic acid and 4,4′-bipyridine

Two coordination complexes, [Co₂L₂(4,4′-bpy)₂(H₂O)₄]?·?6H₂O (1) and [CoL(4,4′-bpy)] (2) (H₂L?=?4,6-bis(4-methylbenzoyl)isophthalic acid and 4,4′-bpy?=?4,4′-bipyridine), have been synthesized with the same starting materials under conventional and hydrothermal condition, respectively. Their structures have been characterized by X-ray diffraction, elemental analysis, IR spectra, and thermogravimetric analysis. Complex 1 features a 2-D sheet structure (space group C2/c) with (4,4) grid units. The non-covalent interactions (O–H?·?·?·?O, C–H?·?·?·?π, and weak π??·?·?·?π interactions) extend 1 into a 3-D supramolecular network. Complex 2 displays a (3,5)-connected network (space group P 1) with a (4²?·?6)(4²?·?6⁸) topology.     

Construction of Zn(II)-ferrocenyl carboxylate coordination complexes via changing adjuvant ligands

Five Zn(II)-ferrocenyl carboxylate complexes, {[Zn(OOCClH₃C₆Fc)(η ²OOCClH₃C₆Fc)(dpa)]?·?(H₂O)} (1), [Zn(η ²-OOCClH₃C₆Fc)₂(2,2′-dip)]?·?(H₂O)_0.25} (2), {[Zn(η-OOCClH₃C₆Fc)₂(bix)]₂?·?(THF)} (3), [Zn(η-OOCClH₃C₆Fc)₂?·?(Hfcz)] _n (4) and {[Zn(η-OOCClH₃C₆Fc)₂(H₂L₁)]?·?(DMF)₂} _n (5) [dpa?=?2,2′-dipyridylamine, 2,2′-dip?=?2,2′-bipyridine, bix?=?1,4-bis(imidazol-1-ylmethyl)benzene, Hfcz?=?α-(2,4-difluorophenyl)-α-(1H-1,2,4-triazol-l-ylmethyl)-1H-1,2,4-triazole-l-ethanol, H₂L₁?=?N,N′-bis(pyridin-4-yl)pyridine-2,6-dicarboxamide, Fc?=?ferrocene, FcC₆H₃ClCOONa?=?sodium 2-chloro-4-ferrocenylbenzoic], have been synthesized and characterized. Single-crystal X-ray analysis reveals that 1 and 2 are mononuclear structures, 3 is a dimer, and 4 and 5 are 1-D structures. The five complexes exhibit some differences in their conformations, which can be attributed to the influence of adjuvant ligands. Notably, various π–π interactions as well as CH/π interactions are discovered in 1–5, and they have significant contributions to self-assembly. The electrochemical properties of 1–5 indicate that half-wave potentials shift to positive potential compared with that of 2-chloro-4-ferrocenylbenzoic acid.     

The construction of two lanthanide coordination polymers based on 5-hydroxyisophthalate and bipyridine

Two lanthanide coordination polymers, [Tm₂·(5-IPA)₄·(2,2′-Hbipy)₂]·3H₂O (1, 5-H₂IPA?=?5-hydroxyisophthalic acid, 2,2′-bipy?=?2,2′-bipyridine) and [Er·(5-HIPA)₃·(4,4′-bipy)₃·(H₂O)₂]·3H₂O (2, 4,4′-bipy?=?4,4′-bipyridine), have formed by hydrothermal synthesis. Complex 1 exhibits a 2-D coordination network containing parallelepiped-shaped voids occupied by guest 2′2-bipy molecules. Complex 2 possesses a 1-D linear chain structure. The 1-D chains are linked by 4,4′-bipy molecules to form a 3-D supramolecular framework. IR spectroscopy, elemental analysis, and thermogravimetric analysis were also investigated.     

Zinc(ΙΙ) complexes with 5,6-dihydro-1,4-dithiin-2,3-dicarboxylic anhydrate and different N-donors: syntheses,crystal structures,and emission properties

Two new Zn^II complexes, {[Zn(L)(phen)(H₂O)]?·?H₂O}_∞ (1) and {[Zn(L)(4bpy)(H₂O)]?·?H₂O}_∞ (2) (L?=?5,6-dihydro-1,4-dithiin-2,3-dicarboxylate, phen?=?1,10-phenanthroline, and 4bpy?=?4,4′-bipyridine), have been prepared by in situ reaction of Zn(ClO₄)₂?·?6H₂O with 5,6-dihydro-1,4-dithiin-2,3-dicarboxylic anhydrate in the presence of lithium hydroxide, together with incorporating chelating phen or bridging 4bpy as co-ligands. Their structures were determined by single-crystal X-ray diffraction. Complex 1 takes a 1-D helical structure that is further assembled into a 2-D network by O–H?···?O, C–H?···?O hydrogen bonds, and weak S?···?S interactions, and then an overall 3-D supramolecular framework was formed by π?···?π stacking interactions. Complex 2 possesses a 2-D (4,4)-layered structure. The structural difference between 1 and 2 can be attributed to the different N-donor auxiliary co-ligands. Both 1 and 2 are photoluminescent materials whose emission properties are closely related to their intrinsic structure.     

Three double- or triple-stranded chains constructed from different cobalt(II) salts and a flexible bis-triazole ligand

Three coordination compounds, {[Co(btrp)₂(H₂O)₂]?·?NO₃?·?H₂O} _n (1), {[Co(btrp)₂(H₂O)₂]?·?H₂O?·?2H₂btc} _n (2), and {[Co(btrp)₃]?·?2ClO₄} _n (3) (btrp?=?1,3-bis(1,2,4-triazol-1-yl)propane; H₃btc?=?benzene-1,3,5-tricarboxylic acid), have been prepared via solvothermal method and characterized by single-crystal X-ray diffraction and elemental analyses. Compound 1 possesses a 1-D double-stranded chain composed of ribbons of 20-membered cycles. Binuclear water clusters link adjacent nitrate anions to form a 1-D supramolecular helix in the structure. Compound 2 has a 1-D double-stranded chain wherein free H₂btc ligands constitute 1-D negative chains through classical hydrogen-bonding interactions (O–H?···?O). Compound 3 exhibits a triple-stranded 1-D chain. For 1–3, 3-D supramolecular structures are consolidated by interchain weak hydrogen-bonding interactions as well as electrostatic interactions.     

Syntheses,structures, and luminescence of coordination compounds based on N-containing polycarboxylates

Six coordination compounds constructed by two structurally related flexible nitrogen-containing polycarboxylate ligands 2,2′-(2,2′-(ethane-1,2-diylbis(oxy))bis(2,1-phenylene))bis(methylene)bis(azanediyl)dibenzoic acid (H₂L1) and 5,5′-(2,2′-(ethane-1,2-diylbis(oxy))bis(2,1-phenylene))bis(methylene)bis(azanediyl)diisophthalic acid (H₄L2) have been synthesized: [Ni(H₂O)₆]?·?L1?·?(C₂H₅OH)_0.5?·?H₂O (1), [Co(L1)(L3)]?·?CH₃OH (2), [Ni(L1)(L3)]?·?CH₃OH (3), [Zn(L1)(L3)]?·?CH₃OH (4), [Cd(L1)(L3)]?·?CH₃OH (5), and [Zn(L2)_0.5(phen)]?·?C₂H₅OH (6), where L3?=?3,4?:?9,10?:?17,18?:?23,24-tetrabenzo-1,12,15,26-tetraaza-5,8,19,22-tetraoxacyclooctacosan and phen?=?1,10-phenanthroline. The crystal structures have been determined by single-crystal X-ray diffraction. Compound 1 displays a discrete structure, which is further linked by hydrogen bonds to form a 2-D supramolecular layer. Compounds 2–5 display similar structures. These compounds possess 1-D meso-chain structures linked by L1 and metals. The C–H?···?π interactions from neighboring chains extend the chains in different directions, giving a 3-D plywood network. Compound 6 possesses 2-D layers, which are further linked by hydrogen-bonding interactions to generate a 3-D supramolecular architecture.     

Crystal structures and luminescence of two cadmium(II) polymers constructed from aromatic polycarboxylate and bis(1,2,4-triazol-1-yl)methane ligands

Two new coordination compounds, {[Cd₂(btrm)(ip)₂(H₂O)₂]?·?2H₂O} _n (1) and {[Cd₂(btrm)(hip)₂(H₂O)₄]?·?3H₂O} _n (2) (btrm?=?bis(1,2,4-triazol-1-yl)methane, H₂ip?=?isophthalic acid, H₂hip?=?5-hydroxy isophthalic acid), have been synthesized and structurally characterized. Compound 1 is a 3-D network with CdSO₄ topology. Compound 2 contains 1-D ladder structures, which are interconnected by classical hydrogen-bonding interactions (O–H?···?O) to lead to 3-D supramolecular architectures. Luminescence was performed on 1 and 2, both of which showed strong fluorescent emissions in the solid state at room temperature.     

Two solvent directed zinc(II) coordination polymers with 1-D single-zigzag chain and 1-D double-zigzag chains

Two coordination polymers, {[Zn(NiL)(DMA)(H₂O)₂] (DMA)(H₂O)} _n (1) (DMA?=?N,N-dimethylacetamide) and {[Zn₂(NiL)₂(DMF)(H₂O)₄]?·?3DMF} _n (2) (DMF?=?N,N-dimethylformamide), have been prepared by reactions of Zn(NO₃)₂?·?6H₂O and NiL in CH₂Cl₂-DMA–H₂O and CH₂Cl₂-DMF–H₂O, respectively. H₂L denotes dimethyl 5,6,7,8,15,16-hexahydro-6,7-dioxodibenzo-9,10-benzo-[1,4,8,11]tetraazacyclotetradecine-13,18-dicarboxylate. Single-crystal X-ray diffraction analyses reveal that coordination geometries around Ni(II) are identical with slightly distorted square planar and all Ni–N bonds are very short. Complex 1 shows 1-D zigzag chain structure, while 2 has 1-D double-zigzag chains. The chains, which are packed parallel in 1 and 2, are interconnected by lattice solvent through O–H···O and C–H···O hydrogen bonds to form 3-D supramolecular networks. We discuss solvent effects on assembly of the two coordination polymers. The results reveal that coordinated solvent has influence on the assembly procedure.     

Syntheses and structural determinations of the nine-coordinate rare earth metal: Na4[DyIII(dtpa)(H2O)]2·16H2O,Na[DyIII(edta)(H2O)3]·3.25H2O and Na3[DyIII(nta)2(H2O)]·5.5H2O

Three complexes, Na₄[Dy^III(dtpa)(H₂O)]₂?·?16H₂O, Na[Dy^III(edta)(H₂O)₃]?·?3.25H₂O and Na₃[Dy^III (nta)₂(H₂O)]?·?5.5H₂O, have been synthesized in aqueous solution and characterized by FT–IR, elemental analyses, TG–DTA and single-crystal X-ray diffraction. Na₄[Dy^III(dtpa)(H₂O)]₂?·?16H₂O crystallizes in the monoclinic system with P2₁/n space group, a?=?18.158(10)?Å, b?=?14.968(9)?Å, c?=?20.769(12)?Å, β?=?108.552(9)°, V?=?5351(5)?ų, Z?=?4, M?=?1517.87?g?mol^?1, D _c?=?1.879?g?cm^?3, μ?=?2.914?mm^?1, F(000)?=?3032, and its structure is refined to R ₁(F)?=?0.0500 for 9384 observed reflections [I?>?2σ(I)]. Na[Dy^III(edta)(H₂O)₃]?·?3.25H₂O crystallizes in the orthorhombic system with Fdd2 space group, a?=?19.338(7)?Å, b?=?35.378(13)?Å, c?=?12.137(5)?Å, β?=?90°, V?=?8303(5)?ų, Z?=?16, M?=?586.31?g?mol^?1, D _c?=?1.876?g?cm^?3, μ?=?3.690?mm^?1, F(000)?=?4632, and its structure is refined to R ₁(F)?=?0.0307 for 4027 observed reflections [I?>?2σ(I)]. Na₃[Dy^III(nta)₂(H₂O)]?·?5.5H₂O crystallizes in the orthorhombic system with Pccn space group, a?=?15.964(12)?Å, b?=?19.665(15)?Å, c?=?14.552(11)?Å, β?=?90°, V?=?4568(6)?ų, Z?=?8, M?=?724.81?g?mol^?1, D _c?=?2.102?g?cm^?3, μ?=?3.422?mm^?1, F(000)?=?2848, and its structure is refined to R ₁(F)?=?0.0449 for 4033 observed reflections [I?>?2?σ(I)]. The coordination polyhedra are tricapped trigonal prism for Na₄[Dy^III(dtpa)(H₂O)]₂?·?16H₂O and Na₃[Dy^III(nta)₂(H₂O)]?·?5.5H₂O, but monocapped square antiprism for Na[Dy^III(edta)(H₂O)₃]?·?3.25H₂O. The crystal structures of these three complexes are completely different from one another. The three-dimensional geometries of three polymers are 3-D layer-shaped structure for Na₄[Dy^III(dtpa)(H₂O)]₂?·?16H₂O, 1-D zigzag type structure for Na[Dy^III(edta)(H₂O)₃]?·?3.25H₂O and a 2-D parallelogram for Na₃[Dy^III(nta)₂(H₂O)]?·?5.5H₂O. According to thermal analyses, the collapsing temperatures are 356°C for Na₄[Dy^III(dtpa)(H₂O)]₂?·?16H₂O, 371°C for Na[Dy^III(edta)(H₂O)₃]?·?3.25H₂O and 387°C for Na₃[Dy^III(nta)₂(H₂O)]?·?5.5H₂O, which indicates that their crystal structures are very stable.     

Two transition metal coordination polymers constructed from 3-aminobenzoate and 4,4′-bipyridine

Two new transition metal coordination polymers, [Zn(abz)(bipy)](ClO₄) (1) and [Mn(bipy)₅(H₂O)₆](ClO₄)_2?·?2(abz)?·?2(H₂O) (2) (bipy?=?4,4′-bipyridine, abz?=?3-aminobenzoate), were prepared and characterized by elemental analysis, FTIR spectroscopy, and single-crystal X-ray diffraction. Complex 1 is a 2-D-layered network with a (4,4) net built up by bipy and 3-aminobenzoate ligands connecting two zinc nodes. Complex 2 is a 3-D supramolecular grid network constructed from close stacking bipy ligands of H-type cation units with large cavities hosting 3-aminobenzoate, perchlorate ions, and water. Solid state photoluminescence for 1 was also investigated.     

Three Cu(II) (R)-2-chloromandelato complexes generated from dipyridyl-type ligands with different spacer lengths: syntheses,crystal structures,and ferroelectric properties

Three Cu(II) complexes, Cu₂(bpy)(H₂O)(Clma)₂ (1), Cu₂(bpe)(H₂O)₂(Clma)₂ (2), and Cu(bpp)(Clma) (3), were synthesized (HClma = (R)-2-Chloromandelic acid, bpy?=?4,4′-dipyridine, bpe?=?1,2-di(4-pyridyl)ethylene, bpp?=?1,3-di(4-pyridyl)propane). Complexes 1, 2, and 3 are constructed from 1-D coordination arrays generated from Cu₂(H₂O)(Clma)₂, Cu₂(H₂O)₂(Clma)₂, and Cu₂(Clma)₂ moieties and linked through bpy, bpe, and bpp co-ligands, respectively. 1 and 2 are assembled into 3-D supramolecular networks via O–H?O hydrogen bonds with topology of (6³)(6⁹·8) and (4¹²·6³), respectively, and 3 is assembled into a 3-D architecture through C–H?O hydrogen bonds with topology of (4³·6³)(4³)(4⁴·6⁵·8)(4⁶·6⁶·8³). Compounds 1, 2, and 3 crystallized in acentric space groups P2₁, P1, and P2₁, which exhibit significant ferroelectricity (remnant polarization Pr?=?0.008?μC?cm^?2, coercive field Ec?=?21.4?kV?cm^?1, the spontaneous saturation polarization Ps?=?0.167?μC?cm^?2 for 1, Pr?=?0.183?μC?cm^?2, Ec?=?1.69?kV?cm^?1, and Ps?=?0.021 μC?cm^?2 for 3). Results from infrared and thermal analyses are also discussed.