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.     

Two cobalt(II) coordination polymers based on carboxylate ligand: Preparation,crystal structures and magnetic properties

Two new coordination polymers, [Co₂(L)_1.5(OH)(H₂O)₂]·2H₂O (1) and [CoL(bpp)] (2) (H₂L = 2,5-dibenzoylterephthalic acid and bpp = 1,3-bis(4-pyridyl)propane), have been synthesized and characterized by elemental analyses, IR spectra, and thermogravimetric analyses. Their structures were determined by single crystal X-ray diffraction analyses. Complex 1 exhibits a 3D framework assembled from tetra-nuclear cobalt-oxygen bridged by carboxylic O atoms with a (4¹²·6³) topology. Complex 2 possesses a 2D layered structure which extends into a 3D architecture via C–H···π interaction between propane proton and the phenyl ring or pyridine ring of an adjacent sheets. Furthermore, the magnetic properties of them are discussed.     

Syntheses,structures and photocatalytic properties of three copper(II) coordination polymers

Three coordination polymers [Cu₂(obtz)₂(tdc)₂]_n (1), {[Cu(obtz)₂(H₂O)₂][Cu₂(obtz)₂(sip)₂]5.5H₂O}_n (2) and [Cu(obtz)(nip)]_n(3) were synthesized by the hydrothermal reaction (obtz = 1.2-bis(1,2,4-triazol-1-ylmethyl)benzene, tdc = 2.5-thiophenedicarboxylate, sip = 5-sulfoisophthalate, nip = 5-nitroisophthalate). 1 shows a ladder-like one-dimensional chain with two side arms. 2 is comprised of two distinct and crystallographically independent polymeric motifs. The first motif in 2 is the ladder-like one-dimensional anionic chain with two side arms. The second motif in 2 is the cationic chain. 3 exhibits the intriguing 2-fold interpenetrated network based on the undulated 2D (4.4) network. 1, 2 and 3 are good photocatalysts for the degradation of methyl orange (MO) under UV irradiation.     

Two Cd(II) coordination polymers based on 3,6-bis(imidazol-1-yl)carbazole: Syntheses,structures and photocatalytic properties

Hydrothermal reactions of CdCl₂·2.5H₂O with 3,6-bis(imidazol-1-yl)carbazole (bmcz), 2-amine-1,4-benzenedicarboxylic acid (2-NH₂-1,4-H₂BDC) or 1,4-naphthalenedicarboxylic acid (1,4-H₂NDC) afforded two coordination polymers, [Cd(2-NH₂-1,4-BDC)(bmcz)]_n (1) and [Cd(1,4-NDC)(bmcz)]_n (2). Complexes 1 and 2 were characterized by elemental analysis, IR, powder X-ray diffraction, and single-crystal X-ray diffraction. 1 and 2 are isomorphic and exhibit 3D supermolecular structures. The solid state luminescent and optical properties of 1 and 2 at ambient temperature were also investigated. A comparative study on their photocatalytic activity toward the degradation of methylene blue in polluted water was explored.     

Syntheses and crystal structures of novel silver(I) coordination polymers based on linear or tetrahedral coordination environments

Two coordination polymers containing Ag(I) atoms, {[Ag(3-pia)](PF₆)}_n (1) and {[Ag(3-pia)₂](PF₆)}_n (2) (3-pia = N-pyridin-3-yl-isonicotinamide), have been synthesized using different solvents, and characterized by single X-ray analyses. In compound 1, Ag(I) atoms are linearly coordinated by two 3-pia ligands, resulting in one-dimensional chains. On the other hand, in compound 2, Ag(I) atoms are tetrahedrally coordinated by four 3-pia ligands, resulting in two-dimensional sheets.     

Divalent cobalt,zinc, and copper coordination polymers based on a new bifunctional ligand: Syntheses,crystal structures,and properties

Three new coordination polymers, namely, [ML(H₂O)]_n (M = Co (1), Zn (2)) and [CuL(DMF)]_n (3), have been hydrothermally synthesized through the reaction of bifunctional ligand 5-((2-methyl-1H-imidazol-1-yl)methyl)benzene-1,3-dioic acid (H₂L) with divalent cobalt, zinc and copper salts, and structurally characterized by elemental analysis, IR and X-ray diffraction. Both complexes 1 and 2 are two-fold interpenetration 3D frameworks. Complex 3 exhibits (3,6)-connected framework with (4.6²)₂(4².6¹⁰.8³) topology. Furthermore, UV–vis absorption spectra and powder X-ray diffraction (PXRD) were investigated as well.     

Syntheses,crystal structures and magnetic property of two azido-bridged coordination polymers with 1,2-diaminocyclohexane as co-ligand

Two azido-bridged coordination polymers, [Ni(L)(μ_1,1-N₃)₂] (1) and [Cu(L)(μ_1,1,3-N₃)(N₃)] (2) (L = 1,2-diaminocyclohexane), have been synthesized and characterized by elemental analyses, IR spectra and X-ray structural analyses. Complex 1 is a one-dimensional helical chain coordination polymer with both azides as μ_1,1-bridge, which exhibits interesting wheel motif. Complex 2 shows two-dimensional layer network in which an azide acts as μ_1,1,3-bridge and the other azide as monodentate ligand. Cyclic voltammogram gives quasi-reversible redox wave of Cu(II)/Cu(I) pair. Variable-temperature magnetic property of 1 was investigated, which shown strong ferromagnetic interaction arising from the μ_1,1-azido bridging nickel(II) chains.     

Syntheses,structures and photoluminescence properties of two 2D Cd(II) coordination polymers based on a semirigid tridentate N-donor ligand

The assembly of a semirigid tridentate N-donor ligand with Cd(II) ions afforded two novel coordination polymers, [Cd(tipa)(H₂O)₂·2NO₃·2DMF·H₂O]_n (1), [Cd₂(tipa)₂Cl₄·2DMF·6H₂O]_n (2), where tipa = tris(4-(1H-imidazol-1-yl)phenyl) amine. Structural analyses indicate that the two compounds feature 2D layered networks. A 3-connected uninodal net with point symbol of (8²·10) is constructed in compound 1 by the connection of tipa and metal ions, in which the terminally coordinated water molecules prevent further extension of the layer. Compound 2 features [Cd₂Cl₄] motifs, which are bridged by tridentate tipa ligands into a 2D (3,6)-connected layer. The results show that tipa with different dihedral angles between benzene ring and terminal imidazole groups can act as versatile building blocks for the generation of various networks. Moreover, the photoluminescence properties of 1 and 2 in the solid state at room temperature have been investigated.     

Two novel Cd(II)-based coordination polymers constructed from isomeric double betaine ligands: Syntheses,structures and fluorescent properties

Two novel Cd^2 + based coordination compounds based on two isomeric double betaine ligands (1,4-Bis(4-carboxylatopyridinium-1-methylene)benzene (H₂L₁Cl₂) and 1,4-Bis(3-carboxylatopyridinium-1-methylene)benzene (H₂L₂Cl₂)) were synthesized, structurally and optically characterized. Both compounds show two dimensional sheet architectures with different features depending on structural motifs that ranging from helical chain to linear chain, and the spatial arrangements of coordinated ligands as well as their unlike coordination modes. They further exhibit the way how three dimensional supramolecular isomers form via weak interactions. Meanwhile, two compounds exhibit intense fluorescence attributing to the ligands' emissions with stokes shift.     

Syntheses,structures and luminescence of three copper(I) cyanide coordination polymers incorporating flexible N-donor ligands

Three copper(I) cyanide coordination polymers, namely [Cu₈(CN)₈(btmb)₂]_n (1), [Cu(CN)(btmb)_0.5]_n (2) and [Cu₂(CN)₂(dpa)]_n (3) (btmb = 1,4-bis(1,2,4-triazol-1-ylmethyl)benzene, dpa = di(4-pyridyl)amine), were synthesized under hydrothermal conditions and characterized by elemental analyses, IR spectra, PXRD and thermogravimetric analyses. Single-crystal X-ray diffraction analyses reveal that complex 1 is an interesting 2D double-layered network constructing from eight distinct Cu(I) centers, eight μ₂-cyanides and two tetradentate cis-btmb ligands. Complex 2 is a ladder-like coordination polymer assembled by CuCN linear chain and bidentate trans-btmb linker. Complex 3 has a 2D wave-like network constructing from CuCN zigzag chain and V-shape dpa spacer. These coordination polymers are thermally stable up to 270–300 °C. They emit blue luminescence originating from ligand-centered emission.     

Two chiral coordination polymers constructed from (1R,2R)-1,2-diaminocyclohexane derivative: Syntheses,structures and properties

Two chiral coordination polymers were synthesized by using a chiral ligand (1R,2R)-1,2-bis(4-(1,2,4-triazolyl))cyclohexane to assemble with Zn(II)/Ag(I) salts. The different coordination modes of the ligand result in two diverse structures, such as a 0D structure for 1 and a 1D chain for 2, respectively. The chiral nature of compounds 1 and 2 was confirmed by circular dichroism spectra (CD) and second harmonic generation (SHG) efficiency measurements. Furthermore, the photoluminescent properties of compounds 1 and 2 have been investigated in the solid state at ambient temperature.     

A new type of copper coordination polymer based on γ-aminobutyric acid: Syntheses,structures and magnetic properties

A copper coordination polymer with γ-aminobutyric acid (GABA), {[Cu₃(GABA)₂(NO₃)₂(OH)₂(H₂O)₂] (NO₃)₂·2H₂O}_n (1), has been synthesized and characterized by single-crystal X-ray diffraction, IR, PXRD, TGA and elemental analysis. It exhibits a 1D chain structure including μ₃-OH-Cu₃ cluster as a building block. The strong H-bonding links these chains to form 2D sheet structure and the main intermolecular interaction between the 2D sheets is electrostatic interaction. According to the crystal structure of complex 1, the magnetic properties of complex 1 have been investigated by the cluster and cycle magnetic coupling models. There are three different magnetic coupling pathways of Cu(II) (J₁, J₂, J₃) from each method and the resulting fitted curves based on the magnetic parameters of both methods compare well with the experiment values.     

Selective adenine/cytosine cations in one-dimensional coordination polymers of manganese (II) and copper (II) 2,3-pyridinedicarboxylates

One-dimensional coordination polymer {[1H,9H-ade]₂[MnL₂]?4H₂O}_n (1) and {[1H,3H-cyt]₂[CuL₂]?6H₂O}_n (2) (ade = adenine, cyt = cytosine, L = dianion of 2,3-pyridinedicarboxylic acid) are selectively synthesized and variable-temperature magnetic susceptibility measurements revealed weak antiferromagnetic interactions within the chains of 1 and 2 (J = ? 0.29 cm^? 1 for 1 and J = ?0.03 cm^? 1 for 2, according to the ? 2J_ijS_iS_j HDvV Hamiltonian formalism).     

One-dimensional helical Cu(II) coordination polymer: Synthesis,structures, and properties

One new Cu(II) coordination polymer (1) based on 6,6′-dihydroxy-2,2′-bipyridine (H₂dhbp) was successfully prepared, with the formula of [Cu(μ₂-OH)(Hdhbp)]_n (1). Single-crystal X-ray analysis shows that compound 1 crystallizes in orthorhombic chiral space group P2₁2₁2₁ and exhibits a left-handed (L) helical [Cu(μ₂-OH)]_n-chain. Luminescence of 1 exhibits a broad emission around 440 nm, attributing to the metal to ligand charge transfer (MLCT). Magnetic susceptibility shows antiferromagnetic coupling within compound 1. Cyclic voltammetry (CV) experiments indicate a potential water oxidation electrocatalyst.     

Assembly of two ferrous coordination polymers with triazole derivative: Syntheses,structures and magnetic properties

The reactions of Fe(II) salts with 1,4-bis(1,2,4-triazole-1-ylmethyl-benzene) (btx) give two new Fe(II) coordination polymers {[Fe(btx)₃](ClO₄)₂}_n (1) and {[Fe(btx)(SO₄)(H₂O)₂]}_n (2), which have been characterized by element analysis, PXRD, single-crystal X-ray diffraction and magnetic susceptibility. 1 shows infinite plait-like chain structure, while 2 exhibits as 2D grid. Magnetic studies indicate that the Fe(II) ions in the two coordination polymers retain in high-spin ground state upon cooling from 300 to 2 K, showing antiferromagnetic interactions.     

Construction of Zn(II)/Cd(II) coordination polymers derived from a tetrazole derivative: Syntheses,structures and luminescent properties

Three new coordination polymers [Zn(Htip)Cl(H₂O)]_n (1), [Zn(Htip)₂]_n (2) and [Cd(Htip)₂]_n·2nH₂O (3) were synthesized by reactions of Zn(II)/Cd(II) salts with a multidentate tetrazole-based ligand 2-(4-(tetrazol-5-yl)phenyl)imidazo(4,5-f)(1,10)phenanthroline (H₂tip). Complex 1 possesses an infinite 1D coordination chain, and further forms the final 3D supramolecule through π⋯π stacking interactions. Complexes 2 and 3 are isomorphous, and both of them feature an 8-fold interpenetrating 4-connected 3D framework with the dia topological net and the Schläfli symbol of {6⁶}. In 1–3, the Htip⁻ ligand links two metal centers through three terminal N-donors. The structural analyses indicate that the anions and solvents can subtly influence the formation of the resulting network. Moreover, the thermal stabilities and photoluminescent properties of 1–3 are investigated in the solid state.     

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 transition metal coordination polymers constructed from 1,4-naphthalenedicarboxylate and N/O-donor auxiliary ligands: Syntheses,structures and magnetic property

Two transition metal coordination polymers (CPs), namely, Cd(1,4-NDC)(py) (1), Co₂(1,4-NDC)₂(DMF)₂ (2) (1,4-NDCH₂ = 1,4-naphthalenedicarboxylic acid, py = pyridine, DMF = N,N-dimethylformamide) have been synthesized and characterized. Compound 1 contains one-dimensional chains, which are further linked by the NDC^2 − ligands to form a three-dimensional framework with a 5,5T2 topology network. There exist two types of left-hand helical chains interconnected to each other through the Cd(II) center in compound 1. Although compound 2 has been reported previously, in this work the synthetic method of 2 is modified to obtain high quality crystals. In addition, the magnetic property of compound 2 is investigated, which shows the metamagnetic behavior induced by the external field.     

3D Ln–Ag (Ln = Nd; Eu) coordination polymers based on N- and O-donor ligands: Synthesis, crystal structures and luminescence

The self-assembly of isonicotinic acid with metal salts under hydrothermal conditions gave two isostructural 3D 4d–4f coordination polymers, Ln₂Ag₄(OX)(IN)₆(H₂O)_1.5 · 2(ClO₄) [Ln = Nd (1); Eu (2), OX = oxalic acid, IN = isonicotinic acid]. Compounds 1 and 2 are 3D coordination frameworks via 2D layers built by carboxylate groups of isonicotinic acid and oxalate ligands coordinating to metal centers and completing the linear linker by silver ions. Furthermore, the luminescent properties of complex 2 have also been investigated.