3D supramolecular open-framework constructed by inorganic [B5O6(OH)4]− and organic [CH3COO]− anions

A borate compound [Ni(en)₃][B₅O₆(OH)₄][CH₃COO] (1) has been synthesized under mild hydrothermal conditions. The newly synthesized compound was characterized by single-crystal X-ray diffraction, elemental analysis and thermogravimetry. The three-dimensional (3D) supramolecular open-framework of compound 1 is constructed by inorganic [B₅O₆(OH)₄]⁻ building units and organic [CH₃COO]⁻ anions through hydrogen bonds, and the charge-balancing [Ni(en)₃]^2 + cations are located in 3D channels. It is very interesting that there exist two helical chains formed by [B₅O₆(OH)₄]⁻ building units and organic [CH₃COO]⁻ anions through hydrogen bonds in compound 1 along different axes. Magnetic measurement indicates that compound 1 exhibits paramagnetic behavior down to 4 K.     

Syntheses,structures and luminescence of two cadmium entangled coordination polymers based on bis(imidazole) and biscarboxylate ligands

Two entangled coordination polymers [Cd₂(bib)(bdc)₂]_n (1) and [Cd₂(bib)(bda)₂]_n (2) were synthesized by the hydrothermal reaction (bib = 1,4-bis(2-methyl-imidazol-1-yl)butane, bdc = 1,2-benzenedicarboxylate, bda = 1,4-benzenediacetate). 1 exhibits an unusual 6-connected self-catenated 3D network based on Cd₂(COO)₂ dimer with the point symbol of (4⁴·6¹⁰·8). 2 exhibits a 3-fold interpenetrating 3D pcu network based on Cd₂(COO)₂ dimer. The different conformations of bib ligands (the anti–anti–anti conformation in 1 and gauche–anti–gauche conformation in 2) play the key role in the construction of different structures in 1 and 2. The luminescence and thermal stability were investigated.     

Two new carboxylate–oxygen bridged trinuclear M(II) (MMn and Co) compounds with zwitterionic dicarboxylate ligands: crystal structures and magnetism

Two new Mn(II) and Co(II) coordination polymers with azide and zwitterionic dicarboxylate ligands L¹ and L² (L¹ = [4-((1-carboxylatobenzyl)pyridimium-3-yl) benzoic acid] chloride, L² = [1,1′-bis(4-carboxylatobenzyl)-4,4′-bipyridinium] dichloride) were synthesized and structurally and magnetically characterized. They are formulated as [Mn₃(L¹)₄(N₃)(CH₃CH₂OH)(H₂O)]ClO₄·4H₂O (1) and [Co₃(L²)₄(N₃)₂(H₂O)₂]·4NO₃ (2). Compound 1 contains two different linear trinuclear [Mn₃(COO)₈(CH₃CH₂OH)₂]^2 − and [Mn₃(COO)₆(H₂O)₂(N₃)₂]^2 − units built from the mixed bridges of (μ-COO)₂(μ₂-O_carboxylate). The trinuclear units are alternately linked into 1D chains by L¹. Compound 2 contains linear trinuclear [Co₃(N₃)₂(COO)₄(H₂O)₂] units built from the mixed bridges (μ-COO)₂(μ-H₂O). Magnetic studies demonstrated that the mixed triple bridges are antiferromagnetic in compounds 1 and 2.     

Hydrothermal synthesis,crystal structure,and thermal stability of a novel 3D cadmium phosphonate with double-stranded helical channels

In the presence of ethylenediamine template agents, a novel 3D cadmium phosphonate with double-stranded helical channels, [enH₂]_0.5[Cd₂(HL)(L)] 1(H₃L =  2-hydroxyphosphonoacetic acid; en = ethylenediamine) has been synthesized by hydrothermal reaction at 140 °C and characterized by single-crystal X-ray diffraction as well as by infrared spectroscopy, elemental and thermogravimetric analysis. The structure of compound 1 comprises right-handed double-stranded helical channels, left-handed double-stranded helical channels and achiral channels that are connected through cadmium atoms and L³⁻ligands to form a meso compound, and the protonated ethylenediamine cations are located inside the achiral channels.     

The novel ligand 4′-phenyl-3,2′:6′,3′′-terpyridine (L) and the supramolecular structure of the dinuclear complex [Zn2(μ-L)(acac)4] · H2O (acac = acetylacetonato)

The new terpyridyl ligand 4′-phenyl-3,2′:6′,3′′-terpyridine (L) reacts with Zn(acac)₂ to produce the dizinc complex [Zn₂(μ-L)(acac)₄] · H₂O (1) (acac = acetylacetonato). The analysis of the crystal structure of this zero-dimensional (0D) complex shows the existence of two Zn(acac)₂ centers bridged symmetrically by one μ-L ligand. The key role played by the acac and L ligands and the guest water molecule allows the generation of a series of intermolecular hydrogen bonds of the O–H/O, C–H/O and C–H/π type which give raise to a 3D supramolecular array. The observed C–H/π interactions are so widespread that all the π-rings present in the structure, viz., those belonging to the L ligand as well as the acetylacetonato chelate rings, participate as hydrogen bond acceptors.     

Hydrothermal syntheses and crystal structures of PbII coordination polymers based on a N,O-donor ligand

In this article, four new lead(II) coordination polymers based on a N,O-donor ligand 2′-(1 H-1,3,7,8-tetraaza-cyclopenta[l]phenanthren-2-yl)biphenyl-2-carboxylic acid (HL) have been hydrothermally synthesized, namely, [PbL₂]·2H₂O (1), [PbL₂]·2H₂O·CH₃CH₂OH (2), [Pb₅L₂(m-BDC)₄]·3H₂O (3) and [Pb₂L₂(p-BDC)] (4), where m-BDC = 1,3-benzenedicarboxylate and p-BDC = 1,4-benzenedicarboxylate. Compound 1 shows a 2D bilayer structure, which is further extended into a 3D supramolecular structure through π–π stacking interactions. Compound 2 shows a 3D supramolecular structure based on a zero-dimensional molecule by π–π stacking interactions of neighboring molecules. Compound 3 shows a 2D layer structure. Compound 4 displays a 1D chain-like structure, which is then stacked by π–π interactions to result in a 2D supramolecular structure. Solid-state luminescent spectra of four lead(II) complexes indicate intense fluorescent emissions.     

A new helical coordination polymer constructed on flexible dicarboxylate ligand and CdII center: Structure and luminescence

A novel cadmium coordination polymer [Cd₂L₂(bpp)₂]_n (1) (H₂L = 1,3-adamantanediacetic acid and bpp = 1,3-di-4-pyridylpropane) was prepared under hydrothermal condition. The three-dimensional (3D) structure is built from the interlinking lamellars. The Cd^II ions are six- and seven-coordinated and linked by L^2? ligands, which results in the right- and left-handed helical chains. The layers are stacked with each other via bpp to generate a 3D architecture. At room temperature, the complex 1 shows the strong fluorescent emission bands in the solid state.     

Six-, seven- and eight-coordinated Cd(II) ions with N-heterocyclic multicarboxylic acids

Two novel cadmium complexes [Cd₃(pta)₂(H₂O)₄]_n (1) (H₃pta = 2,4,6-pyridinetricarboxylic acid) and {[Cd(H₂pza)(H₂O)₂] · 2H₂O}_n (2) (H₄pza = 2,3,5,6-pyrazinetetracarboxylic acid) were synthesized. In both complexes, Cd(II) ions show three different coordination numbers of six and seven in 1 and eight in 2, respectively. Complex 1 displays a three-dimensional network structure and 2 shows a one-dimensional chain structure. The one-dimensional chains in 2 are vertical or parallel to each other and form a three-dimensional network structure by hydrogen bonds. In addition, 1 emits intense fluorescence on excitation of 342 nm.     

1D chain lanthanide coordination polymers with 6-hydroxynicotinic acid: Crystal structures and luminescent properties

Four new lanthanide coordination polymers {[Ln(HL)₂(H₂O)₅] · HL ·  H₂O}_n (Ln = Sm for 1, Eu for 2, Tb for 3 and Dy for 4) (H₂L = 6-hydroxynicotinic acid) have been synthesized and characterized by elemental analysis, FT-IR spectra and X-ray single-crystal diffraction. They all exhibit 1D chain structure, which are further linked via hydrogen bonds to form 3D supramolecular architecture. Luminescent properties of these lanthanide coordination polymers are studied.     

Solvothermal synthesis,crystal structure and photoluminescent property of a novel 3D cadmium(II) coordination polymer containing [Cd5(μ3-OH)2(μ3-OAc)2]6+ cores

A novel 3D coordination polymer, {[Cd₅(μ₃-OAc)₂(μ₂-OAc)₂(μ₃- OH)₂(pam)₂(4,4′-bpy)₂] · CH₃CH₂OH}_n (1) (H₂pam = pamoic acid, HOAc = acetic acid, 4,4′-bpy = 4,4′-bipyridyl), was solvothermally synthesized and characterized by the single crystal X-ray diffraction. The title compound contains unprecedented [Cd₅(μ₃-OH)₂(μ₃-OAc)₂]⁶⁺ pentanuclear building units which are linked through pam and 4,4′-bpy ligands to afford a three-dimensional structure. The infrared spectroscopy, thermal stability and photoluminescence of the complex were studied.     

Temperature-controlled structural diversity of two Cd(II) coordination polymers based on a flexible tripodal multicarboxylate ligand

Two new 3-D Cd(II) coordination polymers (CPs) with 3,5-bi(4-carboxyphenoxy)-benzoic acid (H₃L), namely [Cd₃(L)₂(H₂O)₄]·4H₂O (1) and [Cd₃(L)₂(H₂O)₃]·2H₂O (2), were successfully synthesized under hydrothermal condition at 140 °C and 180 °C, respectively. Complex 1 is constructed from 1-D (–Cd–O–)_∞ rod-shaped SBUs (secondary building units) and ‘Y’-shaped L ligands. In complex 2, the 3-D network is mediated by 2-D [Cd(COO)₂]_n layered motifs and ‘T’ and ‘Y’-shaped L ligands. The results show that the reaction temperature plays a key role on the final structures of the complexes. The luminescent properties of the complexes have also been investigated.     

Porous Cd-carboxylate frameworks tuned by the bulk of linker: Interpenetrated nets,selective CO2 uptakes and high water vapor adsorption

Reported herein are two porous interpenetrated anionic Cd-carboxylate frameworks tuned by the length of organic linker. Shorter BDC linker and [Cd(COO)₄] building blocks in 1 generate a rare 4-connected 2-fold interpenetrating qtz network. But longer NDC linker in 2 produces a self-penetrated 8-connected bcu framework with [Cd₃(COO)₈] SBUs. 1 and 2 both show selective CO₂ adsorption and significantly, 2 exhibits the highest water vapor uptake performance (281 cm³·g^− 1 at 298 K and P/P₀ = 0.95) among all the interpenetrated MOFs.     

An intriguing 4d–4f heterometallic coordination polymer with 1D pseudo-nanotube architectures

A new one-dimensional (1D) 4d–4f heterometallic coordination polymer [ErAg(Himdc)₂(H₂O)₃] (1) (H₃imdc = 4,5-imidazoledicarboxylic acid) is synthesized under hydrothermal condition and characterized by elemental analysis, IR, PXRD and single crystal X-ray diffraction. Complex 1 crystallizes in the triclinic space group P-1, showing a 1D metal–organic pseudo-nanotube with a 4.014 × 12.027 Å² cross-section. Furthermore, it assembles into a 3D supramolecular architecture via hydrogen bonds between pseudo-nanotubes. The complex 1 exhibits solid-state photoluminescence and high thermal stability.     

Hydrogen-bond directed 2D → 3D polythreading of a new luminescent Cd(II) coordination polymer

Solvothermal reactions of Cd(II) salts with biphenyl-3,4′,5-tricarboxylic acid (H₃L) and melamine (MA) afford a new coordination polymer, namely [Cd₃(L)₂(MA)₂(H₂O)₂]_n (1). Single crystal X-ray analysis reveals that compound 1 displays a new 2D → 3D polythreaded motif directed by intermolecular hydrogen bonds, in which large opened windows of each (3,6)-connected layer are threaded by two dangling MA molecules from adjacent layers in the opposite direction. In addition, the luminescent property of 1 was also investigated in the solid state at room temperature.     

Two-dimensional square grid of neutral phosphonate ligands and eight-coordinated metal ions

Two dimensional coordination polymer [CdL₂(NO₃)₂]_n (where L = 4,4′-bis(dimethylphosphonomethyl)biphenyl) has been achieved. The crystal structure and molecular composition are measured using elemental analysis and X-ray crystal structure. Two-dimensional square grid was formed by semi-rigid phosphonate ligands bridge metals, in which the metals adopt rare eight-coordinated geometry. Weak C–H⋯O hydrogen bonds which between coordinated nitrate anion and methyl group of phosphonate ligands link two dimensional grids generating three dimensional supramolecular networks without interpenetration.     

Sandwich type organic-inorganic hybrid of 3d–4f heterometallic containing germanotungstates [{Cu2(1,10-phen)2(μ-CH3COO)2}Ln(α-GeW11O39)2]11 −: Syntheses,crystal structures,magnetic and photoluminescence properties

Alkali salts of organic-inorganic hybrid 3d-4f heterometallic containing derivatives of sandwich type germanotungstates: [{Cu₂(1,10-phen)₂(μ-CH₃COO)₂}Ln(α-GeW₁₁O₃₉)₂]^11 − [Ln = Pr^III (1a), Nd^III (2a), Sm^III (3a), Eu^III (4a), Gd^III (5a); 1,10-phen = 1.10-phenanthroline] have been prepared in the aqueous potassium acetate buffer (pH 4.7) solution. All these compounds were synthesized following by one pot reaction procedure under mild reaction conditions. All compounds were isolated as mixed alkali sodium/potassium salts from the solution and used for further structural characterization by single crystal XRD, powder-XRD, FT-IR, liquid UV/vis, solid state photoluminescence spectroscopy and thermo-gravimetric analysis. FT-IR spectra and powder-XRD pattern suggest that all compounds (1a–5a) are isomorphous. Further single crystal XRD analysis shows that all these compounds exhibit sandwich-type [Ln(α-GeW₁₁O₃₉)₂]^13 − structural feature in the polyoxoanions as the fundamental building block units, and the copper complexes coordinated with 1,10-phen and acetate ligands are coordinated to the terminal oxygen of the polyanion. The compounds 1a, 3a and 4a show good photoluminescence properties at room temperature. The compound 5a shows weak ferromagnetic behavior.     

A polythreaded three-dimensional architecture of undulated layers originated by the contribution of different supramolecular interactions

The structure of compound [Cd₂(NDC)₂(L)₂(H₂O)]·0.5DMF (1) (NDC = 1,4-naphthalenedicarboxylate, L = pyrazino[2,3-f][1,10]phenanthroline and DMF = N,N′-dimethylformamide) is reported. Two independent Cd(II) atoms in a distorted [CdO₄N₂] octahedral environment and three unique NDC ligands showing different coordination modes give strongly undulated two-dimensional grid motifs. Dangling L ligands are chelated to every Cd(II) atom decorating both sides of the layers. Due to the marked undulation of the layers, the large open windows are threaded by the dangling ligands of other layers producing a three-dimensional polythreaded supramolecular array that can be also described as a single three-dimensional framework if the extended columnar face-to-face π–π interactions are considered.     

Unusual metal–organic network constructed from Zn(II), benzenetricarboxylate and bis(1,2,4-triazolyl)pyridine

Hydrothermal reaction of ZnSO₄ · 7H₂O with 1,3,5-benzenetricarboxylic acid (H₃btc) and 2,6-bis(1,2,4-triazolyl)pyridine (btp) afforded a novel metal–organic network {[Zn₃(btc)₂(btp)₂(H₂O)₂] · 4H₂O}_n (1) with a supramolecular cocrystal [H₃btc · btp · H₂O]_n (2). The complex 1 exhibits an unusual network containing two molecular squares and a rectangle. The networks interpenetrate to make a 3D metal–organic framework, which is quite thermal stable. Compound 2 shows a 2D supramolecular network assembled through strong hydrogen bonds.     

Formation of one-dimensional metal–water chain containing discrete water octamers

Discrete water octamers containing 1D metal–water chains have been observed in the complex of [Tb₂(bpdc)(Pic)₂(OH₂)₁₂](Pic)₂ · 4H₂O · (CH₃OH)₂ (Pic = picrate, bpdc = 2,2′-bipyridine-3,3′-dicarboxylate) (1). The water clusters are trapped by the cooperative association of coordinate interactions as well as hydrogen bonds. The intermolecular interaction is robust enough to really act as a ‘supramolecular glue’ to assemble the binuclear coordination complex and picratol into three-dimensional arrays.     

A 3D supramolecular network constructed from {Ni9} cluster and benzotriazole

The solvothermal reaction of Hbta (Hbta = benzotriazole) and Ni(NO₃)₂·6H₂O yielded a blue block crystal, [Ni₉(bta)₁₂(NO₃)₆(DMA)₆]·3DMA (1), (DMA = N,N-dimethylacetamide), which has been characterized by various measurements including elemental analysis, thermogravimetric (TG) analysis, infrared (IR) spectrum, powder X-ray diffraction (PXRD), and X-ray single-crystal diffraction. In compound 1, three crystallographic independent Ni^2 + ions are connected by two types of Hbta ligands to generate a centrosymmetric nine-nuclear {Ni₉} cluster, which could further form a 3D supramolecular network through intra- and intermolecular hydrogen bonds. The TG curve of 1 exhibits a weight loss between 25 and 330 °C, being in accordance with the release of DMA. Furthermore, the variable-temperature magnetic susceptibility of 1 has studied, and the results indicate that antiferromagnetic interactions exist among Ni^2 + ions.