Binuclear, 2D grid and 3D interlocking coordination polymers based on 1,2,4,5-benzenetetracarboxylic acid and 4,4′-azobispyridine

Three new nickel(II) complexes [Ni₂(btec)(azopy)₂(H₂O)₈]·2H₂O (1), {[Ni(H₂btec)(azopy)(H₂O)₂]·(azopy)}_n (2) and {[Ni₄(btec)₂(azopy)₃(H₂O)₁₀]·8H₂O}_n (3) (H₄btec = 1,2,4,5-benzenetetracarboxylic acid; azopy = 4,4′-azobispyridine) have been synthesized by tuning the reaction temperature and the metal–ligand ratio. They were characterized by single-crystal X-ray diffraction and elemental analysis. 1 shows a binuclear structure, 2 exhibits a 2D grid, and 3 features an interesting 3D framework with (6³)(4.6²)(4².6².8²) topology formed by two types of interlocked 2D layers.     

Syntheses,crystal structures,and magnetic studies of two cobalt(II) coordination polymers based on concurrent ligand extension

An ether bridged tetracarboxylic acid ligand, 5-(3′,4′-Dicarboxylphenoxy)-isophthalic acid (H₄L) was used to construct two Co(II) coordination polymers in presence of different nitrogen donor ligands such as 4,4′-bipyridine (4,4′-bpy) and 4,4′-bis(pyrid-4-yl)biphenyl (bpbp). The products formed under hydrothermal conditions are formulated as [Co₂L(4,4′-bpy)₂(H₂O)₃]_n (1) and {[Co(bpbp)₂(H₂L)]·H₂O}_n (2). The compounds were characterized by single-crystal X-ray diffraction, IR spectroscopy, elemental analysis, and powder X-ray diffraction (PXRD) measurement. Compound 1 shows an intriguing (3,4,5)-connected 3D framework with a point symbol of (4² · 6² · 8²)(4² · 6⁵ · 8³)(6² · 8). Compound 2 is an unusual 3D supramolecular framework generated by the one-dimensional [Co(bpbp)(H₂L)]_n polymer chain. The magnetic properties of compounds 1 and 2 were examined, indicating antiferromagnetic interactions between the cobalt(II) ions in the temperature range of 2–300 K.     

An uncommon 3D Co5-cluster-based metal-organic framework: Synthesis,structure and magnetism

A highly connected metal–organic framework (MOF), namely, [Co₅(μ₃-OH)₂(iapt)₄(4,4′-bipy)_0.5(H₂O)·CH₃CN·3H₂O] (1) (H₂iapt = 5-aminoisophthalic acid and 4,4′-bipy = 4,4′-bipyridine), is reported. 1 shows a complicated pentanodal 4,4,4,4,13-c 3D net with (4³)(4³)(4³)(4³)(4²⁰·5¹⁴·6²³·7⁸·8¹³) topology based on an uncommon Co₅ cluster. The magnetic analysis reveals antiferromagnetic interactions in 1, and both the local spin–orbit coupling of octahedral Co(II) ions and the antiferromagnetic interactions are the primary factors in the magnetic behaviour.     

Two corrugated 2D bilayer (63)(658) topological coordination polymers: Synthesis,structure, and water-induced reversible transformation

Two stable supramolecular microporous polymers with double-layer structures, [Co(AIP)(BPY)_0.5 · H₂O]_n · 2nH₂O (1) and [Ni(AIP)(BPY)_0.5 · H₂O]_n · 2nH₂O (2), were constructed from AIP (5-aminoisophthalate) and BPY (4,4′-bipyridine) under hydrothermal conditions. Both of them exhibit rarely reported (3,4)-connected (6³)(6⁵8) topology and interesting water-induced reversible transformation properties that are confirmed by PXRD studies.     

Two d10 coordination polymers based on 4,4′-(hexafluoroisopropylidene)diphthalic acid: Syntheses,structures and physical properties

Two novel coordination polymers, [Zn₂(FA)(4,4′-bipy)₂]·2H₂O (1) and Cd₂(FA)(2,2′-bipy) (2), (H₄FA = 4,4′-(hexafluoroisopropylidene)diphthalic acid, 4,4′-bipy = 4,4′-bipyridine, 2,2′-bipy = 2,2′-bipyridine), have been synthesized under hydrothermal conditions, and their structures were determined by single-crystal X-ray diffraction. Polymer 1 features an unusual three-dimensional (3D) network with (4 · 6² · 8³)(4² · 6² · 8²) topology. Polymer 2 has a complicated 3D framework and crystallizes in non-centrosymmetric space group (Fdd2) belonging to polar point group (C_2v), which displays a strong SHG response and ferroelectric properties. Moreover, the luminescent properties of 1 and 2 have also been investigated.     

Three 3D Cu(II) coordination polymers constructed from 1,2,4,5-benzenetetracarboxylate acid and three positional isomeric ligands

Based on 1,2,4,5-benzenetetracarboxylate acid (H₄btc), and mixed with three isomeric dipyridyl ligands, three novel 3D Cu(II) coordination polymers [Cu₂(btc)(4,4′-bpt)]·2H₂O (1) [4,4′-bpt = 1H-3,5-bis(4-pyridyl)-1,2,4-triazole], [Cu(btc)_0.5(3,4′-bpt)]·0.5H₂O (2) [3,4′-bpt = 1H-3-(3-pyridyl)-5-(4-pyridyl)-1,2,4- triazole] and [Cu(btc)_0.5(3,3′-bpt)]·2H₂O (3) [3,3′-bpt = 1H-3,5-bis(3-pyridyl)-1,2,4-triazole] have been synthesized and characterized, respectively. 1 is a 3D pillared double-layer complex containing a novel bilayer unit; 2 is a 3D pillared-layer architecture with (4,4)-sql layer; 3 exhibits a 3D structure containing 3D [Cu(btc)]_∞ motif and 1D [Cu(bpt)]_∞ chain. The topological analysis shows that 1 can be simplified to a (4,6)-connected network with the Schläfli symbol of (4²·6⁴)₂(4⁸·6⁷), 2 a (4,6)-connected network with the symbol of (4⁴·6²)(4⁴·6¹⁰·8), and 3 a four-connected topology with the symbol of (3²·10³·11)₂(3²·10⁴).     

Three d10 coordination polymers based on rigid ligands with flexible functional groups: Syntheses,structures and luminescence

Three coordination polymers, namely, {[Zn(L)(BPY)]·DMF·H₂O}_n (1), {[Zn(L)(TPY)]·0.5H₂BDC·H₂O}_n (2), {[Cd(L)(H₂O)₂]·DMF}_n (3), have been synthesized based on a rigid linear carboxylate ligand (H₂L = 2′,5′-dimethoxy-[1,1′:4′,1″-terphenyl]-4,4″-dicarboxylic acid) and different lengths of pyridine ligands (TPY = 4,3′:5′,4″-terpyridine; BPY = 4,4′-bipyridine). These complexes have been characterized by single crystal X-ray diffraction, infrared spectroscopy, thermogravimetry, elemental analysis, and powder X-ray diffraction measurements. Complex 1 is a 6-connected 3-fold interpenetrating pcu net with point symbol {4¹² ∙ 6³}, 2 and 3 can be simplified as 4-connected sql nets with point symbol {4⁴ ∙ 6²}. In addition, their photoluminescent properties are also investigated in detail.     

Two new luminescent Cd(II)/Zn(II) metal–organic frameworks for exceptionally selective detection of picric acid explosives

Two new coordination polymers, {[Cd(BIDPT)(oba)]·0.5H₂O}_n (1) and {[Zn(BIDPT)(4,4′-sdb)]·2.25H₂O}_n (2) (BIDPT = 4,4′-bis(imidazol-l-yl)diphenyl thioether, H₂oba = 4,4′-oxydibenzoic acid, 4,4′-H₂sdb = 4,4′-sulfonyldibenzoic acid), have been solvothermally synthesized and characterized. Both 1 and 2 show 2-fold interpenetrating 3D frameworks with {6⁵ ∙ 8} cds and {6⁶} dia topology, respectively. These two coordination polymers show strong luminescence and their luminescence could be quenched by a series of nitro explosives. Importantly, they exhibit very highly sensitive and selective detection of picric acid compared to other nitro explosives.     

Synthesis and characterization of nickel phosphonopropionate hybrid materials

Hydrothermal reaction of nickel acetate with 3-phosphonopropionic acid and 4,4′-bipyridine resulted in two novel phosphonate compounds Ni(HO₃PC₂H₄COO)(4,4′-bpy)(H₂O) · 0.5(4,4′-bpy) (bpy = bipyridine) (I) and Ni(O₃PC₂H₄COOH)(4,4′-bpy)(H₂O)₃ · H₂O (II). Single-crystal X-ray studies reveal that self-assemblies between the ligands and metal ion result in layer (I) and chain (II) structures. Magnetic measurement of I indicate there are ferromagnetic couplings between adjacent Ni²⁺ ions (C = 1.29 cm³ mol⁻¹ K and θ = 2.25 K).     

Two 2-D 4-connected lanthanide coordination framework based on benzimidazole-5,6-dicarboxylate and acetate mixed ligands

Two 2-D polymers, [Ln(bidc)(Ac)·H₂O]_n (Ln = Tb(1), Dy(2) H₂bidc = benzimidazole-5,6-dicarboxylic acid, HAc = acetic acid), have been successfully synthesized under hydrothermal conditions at 150 °C and characterized by elemental analysis, infrared spectra and single-crystal X-ray diffraction. Single crystal X-ray diffraction analyses reveal that the two compounds are isomorphous and exhibit one new (4,4)-connected 2-nodal (4⁴·6²)(4⁴·6²) layer-like net, stabilized by the interchain hydrogen bonding N–H?O, O–H?O and π?π stacking interactions between two benzimidazole rings. 2-D layers are further connected by the interlayer O–H?O hydrogen-bonding interactions to form a 3-D supermoleculaer network. Moreover, the luminescent property of compound 1 and thermogravimetric analyses of the two complexes 1–2 are discussed in detail.     

Construction of a new 3D Zn(II) coordination polymer with (4,6)-connected topology: Synthesis,structure and luminescence

A new coordination polymer of {[Zn₂(odpa)(IP)]·4H₂O}_n (1) (H₄odpa = 3,3′,4,4′-oxydiphthalic acid and IP = 1-H-imidazo[4,5-f][1,10]-phenanthroline), is reported. The 3D (4,6)-connected {4⁴∙6²∙8⁸∙12}{4⁴∙6²} topology net is formed by IP and odpa ligands in 1. Interestingly, the IP ligand acts as a tridentate mode and extends the resulting 3D feature. The luminescence study indicates that the title compound emits bright red fluorescence.     

Assembly of one 2D layer and two 3D pillared-layer structures derived from metal ions and 5-(pyridin-4-yl)isophthalic acid with or without pillars

Three new coordination polymers, [Mn(L)(H₂O)₂]₂·5H₂O (1), [Cu(L)(4,4′-bipy)]₂·H₂O (2) and [Pb(L)(4,4′-bipy)_0.5] (3) (H₂L = 5-(pyridin-4-yl)isophthalic acid; 4,4′-bipy = 4,4′-bipyridine) have been synthesized and characterized by IR, thermogravimetric analysis, X-ray powder diffraction and X-ray single crystal diffraction. Complex 1 shows a 2D layer structure which stacks with the other ones to form 1D channels to hold 1D water chains. Complex 2 displays a 3D + 3D → 3D polycatenation network. 3 shows a unique 2D + 2D → 3D polycatenation net in which each Pb center has a hemidirected coordination geometry due to the existence of “inert pair effect”. The thermal and luminescent properties of 1–3 were also examined.     

Synthesis,structures, luminescent and magnetic properties of four coordination polymers based on biphenyl-2,4′,5-tricarboxylic acid and different N-donor ligands

Four new coordination polymers [Zn(HL)(bibp)]_n (1: H₃L = biphenyl-2,4′,5-tricarboxylic acid, bibp = 4,4′-bis(imidazolyl)biphenyl), [Co(HL)(bibp)]_n (2), [Co(HL)(bib)]_n·4nH₂O (3: bib = 1,4-bis(1-imidazoly)-benzene), [Co_1.5(L)(bib)_1.5(H₂O)]_n·3nH₂O (4), have been synthesized under solvo/hydrothermal conditions, and have been fully characterized by single-crystal X-ray diffraction, powder X-ray diffraction (PXRD), IR spectra, elemental analysis and thermogravimetric analysis (TGA). Structural analyses reveal that both 1 and 2 display a 4-fold interpenetrated framework. Complex 3 possesses a 2D (4,4) network. Complex 4 exhibits a 3D framework with the point symbol of {3²·4·6⁷}₂{3²·6¹⁰·7²·8}. Moreover, photoluminescence properties of 1 and magnetic properties of 2–4 have also been studied in detail.     

A new self-penetrating amine-decorated microporous metal–organic framework: Crystal structure,adsorption selectivity,and luminescence properties

A new microporous metal–organic framework, [Cd(bpdc)_0.5(atz)(DMF)]·0.5DMF (1) (H₂bpdc = 4,4′-biphenyldicarboxylic acid, Hatz = 3-amino-1,2,4-triazole, DMF = N,N-dimethylformamide) has been solvothermally synthesized by employing the mixed H₂bpdc and Hatz ligands. 1 is a 3D pillared-layer framework, consisting of Cd–triazolate layer and dicarboxylate pillar, which exhibits a 6-connected (4⁶ · 6⁸ · 8) self-penetrating net. Because of the pore system functionalized by amino groups and open metal sites, this material shows high CO₂ adsorption selectivity over H₂ and N₂. In addition, 1 exhibits blue emission at ambient temperature.     

A 3D heterometallic Pb(II)-Na(I) coordination polymer as a sensitive and selective fluorescent sensor for detecting Fe3 +

A Pb(II)-Na(I) coordination polymer, {[Pb₃NaL₃](Me₂NH₂)₂(C₂H₅OH)_1.5(H₂O)_10.5}_n (1) (H₃L = 4,4′,4″-s-triazine-2,4,6-triyl-tribenzoic acid), was synthesized under solvothermal condition. This structure crystallizes in the orthorhombic system and shows a 3D pillar-layer network. Topologically, it shows complicate (3,4,5,6,7)-connected net with Schläfli symbol of (4²·6⁸·8⁹·10²)(4³·6²·8)₂(4³·6⁶·8)₂(4⁸·6⁶·8)(6³). Luminescent investigations reveal that 1 can detect Fe^3 + with relative high sensitivity and selectivity, and show broad linear range of 0–1000 μM, as well as low detection limits of 8.65 nM for Fe^3 +.     

Selective sensing of 2,4,6-trinitrophenol and detection of the ultralow temperature based on a dual-functional MOF as a luminescent sensor

A novel 3D Cd(II) MOF, {[Cd(Ccbp⁻)(4.4′-bpy)·H₂O]·(ClO₄⁻)·2H₂O} (1), (Ccbp⁻ = 3-carboxy-1-(4-carboxybenzyl)pyridin-1-ium, 4.4′-bpy = 4.4′-bipyridine), has been successfully synthesized and characterized. Complex 1 possesses a 3D 4-fold interpenetrating dia network with a pyridine cation basic skeleton. This Cd-MOF 1 can be applied as the first potential dual-functional luminescent sensing material for high selective and recyclable sensing of 2,4,6-trinitrophenol and quantitatively detecting the ultralow temperature from 10 to 60 K.     

A new lamellar solid trapping water clusters and intercalated organosulfonate guests

The synthesis and X-ray crystal structure of a lamellar framework with water clusters and organosulfonate guests trapped in the interlamellar region, [Co(H₂O)₂(4,4′-bpy)₂] · (ps)₂ · 10H₂O 1 (4,4′-bpy = 4,4′-bipyridine; Hps = pyridine-4-sulfonic acid), are presented. The structure is made up of cationic square-grid cobalt-4,4′-bipyridine layers with lamellar separation of ca. 8 Å, which is comparable to the hydrotalcite-like solids. The structure also contains intercalated charge-compensating ps⁻ anions and water molecules defining it a hydrotalcite analog.     

Structures and photoluminescence of coordination polymers assembled from bifunctional ligand containing both tetrazole and imidazole groups

Three new coordination polymers, namely, {[Cu₂(IPT)(SO₄)(OH)(H₂O)]·H₂O}_n (HIPT = 5-(4-(1H-imidazol-1-yl)phenyl)- 1H-tetrazolate, 1), {[Cd₂(IPT)(NPA)(OH)]·H₂O}_n (H₂NPA = 5-nitroisophthalic acid, 2), and {[Zn₂(IPT)(IDC)(H₂O)]·3H₂O}_n (H₃IDC = 1H-imidazole-4,5-dicarboxylic acid, 3), were assembled from a bifunctional organic ligand containing both tetrazole and imidazole groups with/without the aid of carboxylate coligands. Compound 1 possesses 2D structure built by 1D [Cu₂(IPT)(SO₄)(OH)]_n secondary building blocks and IPT⁻ linkers. The 2D networks are linked into 3D supramolecular framework via water chains in helical conformation. Compound 2 displays 3D pillar-layer framework with 2D layers based on tetranuclear Cd(II) SBUs and NPA^2 − pillars. Compound 3 exhibits a 3D framework constructed from the interconnection of 1D [Zn-IDC]_n chains and binuclear Zn₂(IPT)₂ rings. The thermal stabilities of porous compound 3 and luminescent properties of compounds 2 and 3 have also been studied in detail. They exhibit intense solid-state fluorescent emissions at room temperature.     

An unprecedented 3D honeycomb-shaped cobalt phosphonate containing sixfold helical chains: Synthesis,crystal structure and thermal stability

A new cobalt(II) phosphonate, [Co(aepa)(4,4′-bpy)(H₂O)₂]·2H₂O 1 (H₂aepa = 2-aminoethylphosphonic acid) has been hydrothermally synthesized and characterized by IR, elemental analysis, TGA and single crystal X-ray diffraction analysis. Compound 1 features a 3D alveolate network structure originating from the intertwist of the rare sixfold 1D helical chains, which are assembled from the coordination of the aepa^2? ligands to the cobalt atoms.     

Synthesis,structure and magnetic properties of a copper molybdate hybrid inorganic/organic solid with a novel 10-connected three-dimensional network topology

Hydrothermal reaction of CuCl₂, MoO₃, and 4,4′-dipyridylketone (4,4′-dpk) afforded green crystals of the mixed metal oxide phase {[Cu₂(MoO₄)₂(4,4′-dpk)(H₂O)]·H₂O}_n (1). According to single-crystal X-ray diffraction, {Cu₂O₂} dimers link into 1-D {Cu₂O₂(μ-H₂O)}_n chains via bridging aqua ligands. These chains form [Cu₂(MoO₄)₂(H₂O)]_n slabs via linkage through tetrahedral molybdate anions. In turn, the copper molybdate slabs are pillared through tethering 4,4′-dpk ligands into a 10-connected three-dimensional lattice with an unprecedented 3¹²4³⁰5²6 topology. Variable temperature magnetic data above 140 K were fit to the Curie–Weiss law, with C = 0.17 cm³ K/mol Cu and Θ = 70 K, indicating likely ferromagnetic coupling within the dinuclear kernels of 1; low temperature data points towards the possibility of interdimer antiferromagnetic interactions.