Synthesis and crystal structures of 3D supramolecular compounds: [ M (4,4′-bipy)2(H2O)4] · (4,4′-bipy)2 · (3,5-daba)2 · 8H2O ( M =Zn,Mn)

Two new supramolecular compounds [M(4,4′-bipy)₂ (H₂O)₄] ·?(4,4′-bipy)₂ ·?(3,5-daba)₂ ·?8H₂O (M=Zn(1) or Mn(2), 4,4′-bipy =?4,4′-bipyridine, 3,5-daba =?3,5-diaminobenzoic acid anion) were synthesized and characterized by elemental analysis and X-ray crystal diffraction. In [M(4,4′-bipy)₂(H₂O)₄]²⁺, the M(II) is coordinated by two nitrogen atoms from two 4,4′-bipy molecules and four oxygen atoms from four waters to form an octahedral configuration. There exist uncoordinated 4,4′-bipy molecules, 3,5-diaminobenzolate counterions and water guests in the compounds. The 3D structures of the title supramolecular compounds are constructed by rich hydrogen bonds among [M(4,4′-bipy)₂(H₂O)₄]²⁺, uncoordinated 4,4′-bipy molecules, water molecules and 3,5-daba, containing a diverting hexa-member water ring.     

Metal–organic Coordination Polymers Assembled from Divalent Transition Salts with a Flexible Spacer Ligand: Hydrothermal Syntheses,Crystal Structures,and Luminescent and Magnetic Properties

Seven new metal-organic coordination polymers, [M(tzda)(H₂O)₄] _n [M = Co(1), Ni (2) and Zn(3)], [Zn(tzda)(4,4′-bipy)] _n (4), [Cd(tzda)(4,4′-bipy)_0.5(H₂O)] _n (5) and [M(tzda)(4,4′-bipy)(H₂O)] _n [M = Co(6), Ni(7)] [H₂tzda = (1,3,4-thiadiazole-2,5-diyldithio)diacetic acid, 4,4′-bipy = 4,4′-bipyridine] have been hydrothermally synthesized and structurally characterized by X-ray single crystal diffraction. Compounds 1–3 display similar 1D zigzag chain structure. Compound 4 possesses a 2D-layered architecture generated from [Zn(tzda)] _n moiety with double-chain structure cross-linking 4,4′-bipy spacers, while compound 5 consists of –Cd–OCO–Cd–OCO– chains cross-linked through –CH₂SC₂N₂SSCH₂– spacers of tzda anions and 4,4′-bipy, also showing a 2D-layered structure. The structures of 6 and 7 seem more complicated, in which the [M(tzda)] _n layered subunits are extended to unique 3D framework by the bridging 4,4′-bipy ligand. Photoluminescence investigations reveal that 4 and 5 both display strong blue emissions in the solid state at room temperature, which could be significant in the field of luminescent materials. The magnetic studies of 6 and 7 show both display the characteristics of a weak antiferromagnetic coupling between metal ions in the system mediated by carboxylate bridges.     

The assembly of POM-induced inorganic–organic hybrids based on copper ions and mixed ligands

Three inorganic–organic hybrid materials based on Keggin-type polyoxometalates (POMs), [Cu^II₂(phen)₂(4,4′-bipy)(H4,4′-bipy)₂(H₂O)₂][PMo₁₂O₄₀]₂·2H₂O (1), [Cu^II(phen)₂(H4,4′bipy)][PW₁₂O₄₀]·H₂O (2), and [Cu^II₂(phen)₂(4,4′-bipy)(BW₁₂O₄₀)(H₂O)₂](H₂4,4′-bipy)_0.5·3H₂O (3) (phen = 1,10-phenanthroline, 4,4′-bipy = 4,4′-bipyridine), were synthesized using different POMs in the hydrothermal conditions. Compounds 1–3 were characterized by single-crystal X-ray diffraction, IR spectra, elemental analyses, powder X-ray diffraction analyses, and thermogravimetric analyses. Compound 1 presents a two-dimensional (2-D) network containing the Keggin-type [PMo₁₂O₄₀]^3? anion and dinuclear metal–organic units [Cu^II₂(phen)₂(4,4′-bipy)(H4,4′-bipy)₂(H₂O)₂]³⁺. Compound 2 is a 2-D architecture constructed from a [PW₁₂O₄₀]^3? and mononuclear metal–organic units [Cu^II(phen)₂(H4,4′-bipy)]³⁺. In 3, the [BW₁₂O₄₀]^5? anions link [Cu^II₂(phen)₂(4,4′-bipy)] units to form a one-dimensional (1-D) chain [Cu^II₂(phen)₂(4,4′-bipy)(BW₁₂O₄₀)(H₂O)₂]; the 1-D chain connects with protonated 4,4′-bipy ligands and lattice waters, yielding a 2-D layer. Fluorescence spectra, UV–vis spectra, and electrochemical properties of 1–3 have been investigated.     

Synthesis,structure, and character of two rare earth carboxylic acid complexes

Two rare earth carboxylic acid complexes, [Sm(MeBA)₃(2,2′-bipy)]₂·2(2,2′-bipy) (MeBA = 3-methylbenzoic acid; 2,2′-bipy = 2,2′-bipyridine) (1) and [Pr(MeBA)₃(H₂O)₂]_n?n(4,4′-bipy) (4,4′-bipy = 4,4′-bipyridine) (2), have been synthesized under hydrothermal conditions and structurally determined by single-crystal X-ray diffraction. Compound 1 is a dimer and further assembles into an infinite chain, two-dimensional net and three-dimensional supramolecular structure via weak π–π and C–H···π interactions. Some 2,2′-bipy coordinates with Sm and some exist by non-covalent C–H···π interactions. Compound 2 is a 1D infinite chain structure, with adjacent 1D chains connected into a 2D layer structure by O–H···N hydrogen bonds. The two complexes were characterized by elemental analyses, IR, photoluminescence, and TGA. In order to illustrate subtle structural characteristics of intermolecular interactions and magnetic sensitivity of the complex, 2D-IR correlation spectra (2D-IR COS) under magnetic perturbation for 1 were performed.     

Syntheses,structures, and properties of four coordination compounds constructed from asymmetric semi-rigid V-shaped multicarboxylate ligand

Four new compounds, [Mn(HL)(phen)₂(H₂O)] (1), [Ni(HL)(phen)₂(H₂O)] (2), [Zn(HL)(4,4′-bipy)_1.5(H₂O)] _n ?·?2nH₂O (3) and [Zn₂(HL)₂(H₂O)₆] (4), have been synthesized from an asymmetric semi-rigid V-shaped multicarboxylate 4-(4-carboxy-phenoxy)-phthalic acid (H₃L) with 1,10-phenanthroline (phen), or 4,4′-bipyridine (4,4′-bipy) as auxiliary ligands. Single-crystal X-ray diffraction analysis reveals that 1, 2 and 4 have 0-D structures with 3-D supramolecular frameworks formed by intermolecular hydrogen bonds. Compound 3 shows a 1-D infinite ribbon bridged by 4,4′-bipy, which further forms a 3-D supramolecular architecture by π–π stacking interactions and hydrogen bonds. Thermal stabilities of 1–4 and luminescence properties of 3 and 4 have also been investigated.     

Architectural diversity of six coordination compounds based on (S)-(+)-mandelic acid and different N-donor auxiliary ligands: syntheses,structures, and luminescent properties

Six transition metal coordination compounds with H₂mand and different N-donor ligands, [Co(Hmand)₂(2,2′-bipy)]·H₂O (1), [Ni(Hmand)₂(2,2′-bipy)]·H₂O (2), [Ni(Hmand)₂(bpe)] (3), [Zn(Hmand)₂(2,4′-bipy)(H₂O)]·2H₂O (4), [Zn(Hmand)(bpe)(H₂O)]_n[(ClO₄)]_n·nH₂O (5), and [Zn(Hmand)(4,4′-bipy)(H₂O)]_n[(ClO₄)]_n (6), were synthesized under different conditions (H₂mand = (S)-(+)-mandelic acid, bpe = 1,2-di(4-pyridyl)ethane, 4,4′-bipy = 4,4′-bipyridine, 2,4′-bipy = 2,4′-bipyridine, 2,2′-bipy = 2,2′-bipyridine). Their structures were determined by single-crystal X-ray diffraction analysis and further characterized by elemental analysis, infrared spectra, thermogravimetric analysis, powder X-ray diffraction, and circular dichroism. Compounds 1 and 2 are isostructural (0-D structures), which are extended to supramolecular 1-D chains by hydrogen bonding. Compound 3 exhibits 1-D straight chain structures, which are further linked via hydrogen bond interactions to generate a 3-D supramolecular architecture. Compound 4 displays a discrete molecular unit. Neighboring units are further linked by hydrogen bonds and π–π interactions to form a 3-D supramolecular architecture. Compound 5 displays a 2-D undulated network, further extended into a 3-D supramolecular architecture through hydrogen bond interactions. Compound 6 possesses a 2-D sheet structure. Auxiliary ligands and counteranions play an important role in the formation of final frameworks, and the hydrogen-bonding interactions and π–π stacking interactions contributed to the formation of the diverse supramolecular architectures. Compounds 1, 2, 4, 5, and 6 crystallize in chiral space groups, with the circular dichroism spectra exhibiting positive cotton effects. Furthermore, the luminescent properties of 4–6 have been examined in the solid state at room temperature, and the different crystal structures influence emission spectra significantly.     

Zinc(II) and manganese(II) coordination polymers constructed by 2-naphthyl imidazole dicarboxylate: syntheses,structures and properties

Three coordination polymers [Zn(μ₃-HNIDC)(CH₃OH)]_n (H₃NIDC = 2-(2-naphthyl)-1H-imidazole-4,5-dicarboxylic acid) (1), [Mn(μ₂-HNIDC)(4,4′-bipy)]_n (4,4′-bipy = 4,4′-bipyridine) (2) and [Mn₂(μ₂-HNIDC)₂(phen)₂]_n (phen = 1,10-phenanthroline) (3) have been solvothermally synthesised and structurally characterised by single-crystal X-ray diffraction, elemental analyses, thermal analyses and IR spectra. Polymer 1 displays a three-dimensional open architecture with one-dimensional (1D) channels. Polymer 2 exhibits a sheet structure containing infinite rectangles. Polymer 3 presents a 1D wave chain structure. The solid-state photoluminescence of 1 has been investigated as well.     

Two zinc(II) complexes based on indole-3-acetic acid: crystal structures,fluorescence sensors,and ion exchange with mercury(II)

Two new coordination complexes, [Zn(IA)₂(phen)] (1) and [Zn(IA)₂(4,4′-bipy)] _n ?·?C₂H₅OH (2) (IAH?=?indole-3-acetic acid, phen?=?1,10-phenanthroline, 4,4′-bipy?=?4,4′-bipyridine), have been prepared and characterized by single-crystal X-ray diffraction. Complex 1 is mononuclear and 2 presents a 1-D zigzag chain, in which 4,4′-bipy connects the Zn(II) ions. Both complexes show fluorescence emissions and exhibit fluorescence quenching when Hg²⁺ ions are present. ICP, EDS, and SEM experiments reveal that zinc in both complexes can be exchanged by toxic mercury ions.     

Syntheses,structures, and properties of three MOFs based on tertbutylphenyl imidazole dicarboxylate

By hydrothermal reactions of a newly designed ligand, 2-(p-tert-butylphenyl)-1H-imidazole-4,5-dicarboxylic acid (H₃BuPhIDC) with Cd(II) or Zn(II), three metal-organic frameworks, [Cd(μ₃-HBuPhIDC)(H₂O)]·2H₂O (1), [Cd(μ₃-HBuPhIDC)(4,4′-bipy)_0.5] (4,4′-bipy = 4,4′-bipyridine) (2), and [Zn₂(μ₃-HBuPhIDC)₂(CH₃OH)₂] (3), have been obtained and characterized by elemental analyses, IR spectroscopy, and single-crystal X-ray diffraction. In 1, small countless diamond grids form a mesh structure and then are bridged through μ₃-HBuPhIDC^2? linkers building a 3-D framework. Compared with 1, 4,4′-bipy participates in the construction of a 3-D structure of 2. Polymer 3 shows an interesting 3-D open architecture, which contains infinite 1-D octagonal channels built by left- and right-handed helical chains. Thermal and solid-state photoluminescence properties of the polymers have been investigated.     

Two new Pb(II) coordination polymers, [Pb2(μ-4,4′-bipy) (μ-2-sb)2(DMF)] n and {[Pb2(μ-4,4′-bipy) (μ-2-sb)2(H2O)2] · H2O} n (4,4′-bipy = 4,4′-bipyridine and 2-H2sb = 2-sufobenzoic acid)

Two new 2D Pb₂(μ-4,4′-bipy)(μ-2-sb)₂ coordination polymers, [Pb₂(μ-4,4′-bipy)(μ-2-sb)₂(DMF)] _n (1) and {[Pb₂(μ-4,4′-bipy)(μ-2-sb)₂(H₂O)₂] · H₂O} _n (2), have been synthesized, characterized and studied by X-ray crystallography. The structural studies show the Pb atoms to have seven- and eight-coordinate holodirected geometries.     

Synthesis,structure and photoluminescent properties of a new coordination polymer [Cd2(pzdc)2(4,4′-bpy)(H2O)2] n (H2pzdc = pyrazine-2,3-dicarboxylic acid, 4,4′-bpy = 4,4′-bipyridine)

A new 2D coordination polymer, [Cd₂(pzdc)₂(4,4′-bpy)(H₂O)₂] _n (1) (pzdc = pyrazine-2,3-dicarboxylic acid, 4,4′-bpy = 4,4′-bipyridine), has been hydrothermally synthesized and characterized by elemental analyses, IR spectra and single crystal X-ray diffraction. X-ray diffraction analysis reveals that 1 features an interesting 2D stair-like layer with linear [Cd₂(pzdc)₂(H₂O)₂] _n ribbons linked by 4,4′-bpy bridges. Furthermore, these layers are packed in an ABAB arrangement to give a 3D supramolecular network via hydrogen bonding and π–π packing interactions. Compound 1 displays strong fluorescent emission in the solid state at room temperature.     

New nano-particle La(III) supramolecular compound as a precursor for preparation of lanthanum oxybromide-, hydroxide-, and oxide-nanostructures

Nano-particles of a new La(III) supramolecular compound [La(4,4′-bipy)(H₂O)₂(NO₃)_3.75Br_0.25] · (4,4′-Hbipy) (1), have been synthesized from reaction of 4,4′-bipy with La(NO₃)₃ and NaBr by the sonochemical method. For the first time LaOBr, La(OH)₃ and La₂O₃ nano-structures were prepared from [La(4,4′-bipy)(H₂O)₂(NO₃)_3.75Br_0.25] · (4,4′-Hbipy) (1) by calcination at 400, 500, and 700°C, respectively. The structure of 1 was determined by X-ray crystallography and the nano-structures were characterized by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). Thermal stabilities of nano and crystal samples of 1 were studied and compared with each other.     

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.     

Hydrothermal syntheses and structural characterization of two organic–inorganic hybrid compounds based on Lindqvist polyanions

Two organic–inorganic hybrid polyoxometalates {[V₂W₄O₁₉{Cu(2,2′-bipy)₂}₂] · (4,4′-bipy)} _n (1) and [Co(2,2′-bipy)₃][W₆O₁₉] · H₂O (2) (2,2′-bipy = 2,2′-bipyridine, 4,4′-bipy = 4,4′-bipyridine), constructed by Lindqvist polyanions and transition metal coordination cations, have been synthesized under hydrothermal conditions and characterized by elemental analysis, IR, UV spectra, thermogravimetric (TG) analyses, X-ray photoelectron spectroscopy (XPS), and single- crystal X-ray diffraction. Compound 1 is a neutral molecule and consists of a di-V^V substituted Lindqvist-type polyanion [V₂W₄O₁₉]^4?, two supporting copper cations [Cu(2,2′-bipy)₂]²⁺ and one free 4,4′-bipy. Neutral molecules of 1 are extended to a 2-D grid-like network by π–π stacking interactions between pyridine groups. The molecular structure of 2 contains one [W₆O₁₉]^2? cluster polyanion and a [Co(2,2′-bipy)₃]²⁺. Inductively coupled plasma (ICP) analysis and XPS spectrum of 1 prove the presence of V^V. TG curves of 1 and 2 indicate two weight loss steps.     

A one-dimensional organic–inorganic hybrid constructed by saturated Keggin polyoxoanions and [CuI(4,4′-bipy)] n n + chains

A one-dimensional (1-D) organic–inorganic hybrid compound {(H₃O)[Cu^I(4,4′-bipy)]₃[SiW₁₂O₄₀]} · 1.5H₂O (1) has been synthesized from hydrothermal reaction of Keggin polyoxometalate, cupric nitrate and 4,4′-bipyridine (4,4′-bipy). Single crystal X-ray diffraction shows 1-D zigzag chains built up of saturated Keggin polyoxoanions and infinite [Cu^I(4,4′-bipy)] _n ^{n +} units. Zipper-like arrangement of adjacent zigzag chains by hydrogen-bonding interactions leads to a 2-D layer and π–π interactions of 4,4′-bipy ligands from adjacent layers further result in the 3-D structure of 1. All Cu atoms in 1 are three-coordinated with “T-type” geometries, indicating they are univalent in the resultant compound. This result has further been confirmed by the absence of signal in the EPR spectrum of 1.     

Five metal imidazole dicarboxylate-based compounds comprising M3(MIDC)2 entities (M = Zn2+, Co2+, Mn2+): syntheses,structures and properties

Five metal imidazole dicarboxylate-based compounds, {[Zn₃(MIDC)₂(4,4′-bipy)₃](4,4′-bipy)·8H₂O}_n (1), {[Co₃(MIDC)₂(4,4′-bipy)₃](4,4′-bipy)·6H₂O}_n (2), {[Co₃(MIDC)₂(py)₂(H₂O)₂]}_n (3), {[Mn₆(MIDC)₄(py)₅(H₂O)₄]}_n (4), and {[Mn₃(MIDC)₂(Phen)₃(H₂O)₂]}_n (5) (H₃MIDC = 2-methyl-1H-imidazole-4,5-dicarboxylic acid; 4,4′-bipy = 4,4′-bipyridine; py = pyridine; Phen = 1,10-phenanthroline), have been synthesized under hydrothermal conditions and characterized by elemental analyses, IR spectroscopy, thermogravimetric analysis, and single-crystal X-ray diffraction. We control the coordination modes of H₃MIDC via hydrazine and obtained a series of coordination compounds containing honeycomb-like [M₃(MIDC)₂]_n layers. We also investigated the effects of different neutral terminal or bridging ligands on [M₃(MIDC)₂]_n layers. Coplanar [M₃(MIDC)₂]_n layers and 4,4-bipy were used to construct 3-D frameworks of 1 and 2. Puckered [M₃(MIDC)₂]_n layers were found in 3–5; 4 is the first [M₃(L)₂]_n layer structure with two crests and troughs during each period (L = imidazole-4,5-dicarboxylic acid or its analog). Compound 5 is the first puckered [M₃(L)₂]_n layer structure decorated by chelating neutral ligands. Compound 1 exhibits weak blue photoluminescence in the solid state at room temperature. Variable-temperature magnetic susceptibility measurements of 2–5 indicate strong antiferromagnetic interactions.     

A new Zn(II) complex of unusual unidentate coordination of 4,4′-bipyridine, a new precursor for the preparation of zinc(II) oxide nanoparticles

A 4,4′-bipyridine Zn(II) complex [Zn(4,4′-bipy)₂(H₂O)₄](ClO₄)₂·4(4,4′-bipy) is synthesized, characterized by elemental analysis, IR, ¹H NMR, ¹³C NMR spectroscopy, and studied by X-ray crystallography. The compound forms monomeric units as a result of unusual unidentate coordination of 4,4′-bipy ligands. The thermal stability of the compound is studied by thermal analyses. Furthermore, the complex is luminescent with emission maxima at 329 nm in the methanol solvent. Different sizes of zinc(II) oxide nanoparticles are prepared by calcination of the [Zn(4,4′-bipy)₂(H₂O)₄](ClO₄)₂·4(4,4′-bipy) compound at two different temperatures. These nanostructures are characterized by X-ray powder diffraction and scanning electron microscopy.     

Three transition-metal polymers from imidazole dicarboxylates-bearing methoxyphenyl groups: syntheses,crystal structures and properties

Three coordination polymers, namely, {[Cu₂(HMOPhIDC)(4,4′-bipy)]}_n (H₃MOPhIDC = 2-(3-methoxyphenyl)-1H-imidazole-4,5-dicarboxylic acid) (1), [Co(HDMOPhIDC)(phen)]_n (H₃DMOPhIDC = 2-(3,4-dimethoxyphenyl)-1H-imidazole-4,5-dicarboxylic acid) (2) and [Ni₂(HDMOPhIDC)₂(H₂O)₄]_n (3) have been prepared under hydrothermal condition and characterised by elemental analyses, infrared spectroscopy and single-crystal X-ray diffraction. Each of the polymers 1–3 is a 1D column-like structure and displays a 3D supramolecular network via the π…π stacking or hydrogen bond interactions. Furthermore, fluorescence and UV–vis spectroscopic properties of the polymers have been studied.     

New complexes of Zn(II) with the anti-inflammatory non-steroidal drug,ibuprofen and nitrogen donor ligands. Synthesis,characterization and biological activity

Complexes of [Zn(ibup)₂(4,4′-bipy)]_n 1, [Zn(ibup)₂(phen)] 2, [Zn(ibup)₂(2,9-dmphen)] 3, [Zn(ibup)₂(1,2-dmimidazole)₂] 4, and [Zn(ibup)₂(2-am-6-picoline)₂] 5 (ibu = ibuprofen, 4,4′-bipy = 4,4′-bipypyridine, phen = 1,10-phenanthroline, 2,9-dmephen = 2,9-dimethyl-1,10-phenanthroline, 1,2-dmimidazole = 1,2-dimethylimidazole, and 2-am-6-picoline = 2-amino-6-picoline) were prepared and characterized. The crystal structure of 1 was determined by single-crystal X-ray diffraction. The in vitro anti-bacterial activities for the complexes against Gram-positive (Micrococcus luteus, Staphylococcus aureus and Bacillus subtilis) and Gram-negative (Escherichia coli, Klebsiella pneumonia and Proteus mirabilis) bacteria were done using the agar well-diffusion method. Complexes 1–3 showed anti-bacterial activity against Gram-positive bacteria, while 4 and 5 did not exhibit anti-bacterial activity. Complexes 2 and 3 were selected for further studies. Complexation of zinc-ibuprofen with phen as in 2 decreased the anti-bacterial activity against most of the bacteria used. The complexation in 3 decreased the anti-bacterial activity in Gram-positive bacteria but for Gram-negative bacteria, the overall anti-bacterial activity of uncoordinated 2,9-dmphen was enhanced upon coordination with zinc ibuprofen.