Entangled Coordination Polymers Research Articles

Solvothermal synthesis and crystal structures of two Holmium(III)-5-Hydroxyisophthalate entangled coordination polymers and theoretical studies on the importance of π•••π stacking interactions

Two new Ho(III)-5-hydroxyisophthalates with the formulae; {[Ho(hip)(H2O)5].(NO2).H2O}n (1) and {[Ho4(hip)4(H2O)20].2(hip2−).8H2O}n (2) were solvothermally synthesized by self-assembly of Ho(III)-nitrate with rigid 5-hydroxyisophthalic acid (H2hip) linker. The coordination polymers (CPs) 1 and 2 crystallize in monoclinic P21/c and P21/n space groups, respectively. Both the CPs 1 and 2, shows 1D linear ladder shaped extension with the linkage having the backbone of hip2− moieties. In the both CPs 1 and 2, the Ho centers are nine coordinated. In CP 1, Ho shows distorted tricapped trigonal prismatic geometry while in CP 2, four Ho centres display three different geometries (monocapped square antiprismatic geometry around Ho1 and Ho3; distorted tricapped trigonal prismatic geometry around Ho2 and; distorted monocapped square antiprismatic geometry around Ho4). The organic linker hip2− exhibits only one coordination mode (μ2-κO,O:κO,O). Theoretical calculations have been performed to analyze the antiparallel and parallel π stacking interactions observed in the solid-state structures of coordination polymers1 and 2, respectively. The DFT study is focused on the energetic features of the π-stacking, the influence of the ligand coordination to Ho upon the π-stacking strength and their characterization by the noncovalent interaction plot (NCIplot) index computational tool.

Reversible Switching of Frameworks through Single-Crystal-to-Single-Crystal Structural Transformation in Two Entangled Coordination Polymers and Their Impact on Adsorption Properties

Two coordination polymers (CPs) with a different framework entanglement, namely, a triply interpenetrated two-dimensional (2D) sheet of {[Zn(bpe)(pim)]·(bpe)0.5(H2O)3}n (1) and a doubly interpenetr...

Self-assembly of three novel entangled polyoxometalate-based coordination polymers with redox properties

Three novel entangled coordination polymers (CPs), namely, [Cu4(BPB)5(HPW12O40)2]·2H2O (JOU-15), [Cu3(BPB)3PW12O40] (JOU-16), and [Cu3(BPBP)3PW12O40] (JOU-17), have been successfully synthesized by combining flexible N-donor ligands and Keggin type polyoxometalates with copper ion under hydrothermal conditions. Structural characterizations show that JOU-15 features an unusual 1D + 1D → 2D entangled network with the coexistence of polycatenation and interdigitation. JOU-16 exhibits a fascinating self-catenated three-dimensional framework with a new point symbol of (44·610·8)(65·8)(66). JOU-17 displays a novel 1D + 3D + 3D → 3D entangled framework with features of both polycatenation and polythreading. In addition, the electrochemical properties of these compounds have also been studied.

Effect of ligand on the assembly of two entangled coordination polymers: Structures and photocatalytic properties

Two new Cd(II) coordination polymers, namely [Cd(L)(bbi)] (1) and [Cd(L)(bpz] (2) (H2L = 4,4′-{[1,2-phenylenebis-(methylene)]bis(oxy) dibenzoic acid, bbi = 1,1′-(1,4-butanediyl)bis(imidazole) and bpz = 3,3′,5,5′-tetramethyl-4,4′-bipyrazole), were prepared and structurally characterized. 1 shows a 2D channel-like architecture with a self-threaded feature. 2 holds a 2D layer structure, having a 2D + 2D → 2D network. The results demonstrate that the flexibilities of the ligands make an impact on the structural diversities of the entangled coordination polymers. Moreover, 1 and 2 possess catalytic efficiency for the photodecomposition of methyl violet (MV).

Two New Entangled Zn and Cd Coordination Polymers Based on a Rich “Mix” Feature of the O- and N-Donor Ligand System: Synthesis, Structure, and Fluorescent Properties

A prominent mixed-ligand system with rich “mix” features, which are rigid multicarboxylate O-donor ligands cooperating with flexible bisazole N-donor linkers, is explored to coordinate with Zn2+/Cd2+ centers. Two new entangled coordination polymers ([Cd(Hbtc)(bbi)] (1) and [Zn(btec)0.5(dtp)]·5H2O (2)) are gained. Complex 1 exhibits a fascinating 3D (3,5)-connected net with a Schlafli symbol of the (63.610) topology, and 3D nets penetrate into each other to give rise to twofold interpenetrations. Complex 2 displays a 2D layer with similar 9.9×12.0 A2 hexagonal channels, the adjacent layers stacking with each other to form a 3D supramolecular structure. The effects and functions of the ligands in the complexes are discussed. Moreover, the thermal stabilities and fluorescence properties of complexes 1 and 2 are investigated.

A 3D interpenetrated Co(II)-glutarate coordination polymer: Synthesis, crystal structure, magnetic and adsorption properties

A 3D entangled coordination polymer {[Co4(glu)4(bpp)2]}n1 was synthesized from a solvothermal reaction between Co(II), glutaric acid (H2glu) and 1,3-bis(4-pyridyl)propane (bpp). The crystal structure was determined by single crystal X-ray diffraction and the topological description indicates a 3D → 3D interpenetration in the pcu-coordination polymer, pillared by bpp ligands. Crystal structure presents four crystallographically distinct Co(II) metal centers conferring different coordination environments: tetrahedral, octahedral and trigonal bipyramidal. Spectroscopic (FTIR and Raman), thermal analysis and magnetic studies were employed to chemical characterization. SQUID magnetometry analysis indicated weak overall antiferromagnetic interactions between the Co(II) ions. High-Field Electron Paramagnetic Resonance (HFEPR) spectra suggest that the Co(II) ions in compound 1 are high-spin (S = 3/2). The material showed good thermal stability decomposing above 300 °C. CO2 adsorption studies carried out in the pressure range of 0 to 40 bar at room temperature revealed a favorable solid-gas interaction at low pressure. The amount of CO2 adsorbed on compound 1 continuously increased as the pressure increased and no gas saturation is observed suggesting a multilayer phenomenon of CO2 uptake. Powder X-ray diffraction analysis of compound 1 after CO2 measurements at 40 bar revealed no structural change.

Two new entangled Zn and Cd coordination polymers based on a rich «mix» feature of the O- and N-donor ligand system: Synthesis, structure, and fluorescent properties

A prominent mixed-ligand system with rich «mix» features, which are rigid multicarboxylate O-donor ligands cooperating with flexible bisazole N-donor linkers, is explored to coordinate with Zn2+/Cd2+ centers. Two new entangled coordination polymers ([Cd(Hbtc)(bbi)] (1) and [Zn(btec)0.5(dtp)]×5H2O (2)) are gained. Complex 1 exhibits a fascinating 3D (3,5)-connected net with a Schläfli symbol of the (63.610) topology, and 3D nets penetrate into each other to give rise to twofold interpenetrations. Complex 2 displays a 2D layer with similar 9.9·12.0 Å2 hexagonal channels, the adjacent layers stacking with each other to form a 3D supramolecular structure. The effects and functions of the ligands in the complexes are discussed. Moreover, the thermal stabilities and fluorescence properties of complexes 1 and 2 are investigated.

Construction of a magnetic chiral coordination polymer based on a semi-rigid carboxylic acid

A 2-D chiral entangled coordination polymer, {Mn3(2,2′-bpy)2(3-cpta)2·H2O}n (1) (3-H3cpta=3-(3′-carboxyphenoxy)phthalic acid, 2,2′-bpy=2,2′-bipyridine), has been synthesized via the solvothermal method. X-ray diffraction analysis reveals that 1 consists of one right-handed helical chain and one wavelike 2-D plane, which are connected with each other through hydrogen bonds and π···π interactions to generate a 3-D supra-molecule. Thermal gravimetric analysis shows that 1 possesses good thermal stability. Temperature dependent magnetic susceptibilities have also been measured from 1.8 to 300 K, which shows 1 to be anti-ferromagnetic.

Structural diversity of six metal–organic frameworks from a rigid bisimidazole ligand and their adsorption of organic dyes

Six entangled coordination polymers from a bisimidazole ligand and versatile carboxylate acids have been synthesized and structurally characterized. Their adsorption behaviors to organic dyes have also been evaluated.

A family of entangled coordination polymers constructed from a flexible V-shaped long bicarboxylic acid and auxiliary N-donor ligands: Luminescent sensing

Eight Zn(II)-based coordination polymers, namely, [Zn2L2(2,2’-bipy)]n·nH2O (1), [Zn2L2(phen)]n·nH2O (2), [ZnL(phen)(H2O)]n (3), [Zn3L3(4,4’-bipy)]n (4), [Zn2L2(4,4’-bipy)2]n [Zn2L2(H2O)2]n·2nH2O (5), [Zn4L4(bpp)2]n (6), [ZnL(bbi)0.5]n (7), [ZnL(bpz)]n (8) (H2L=4,4’-{[1,2-phenylenebis-(methylene)]bis(oxy)}dibenzoic acid, 2,2’-bipy =2,2’-bipyridine, phen =1,10-phenanthroline, 4,4’-bpy=4,4’-bipyridine, bpp =1,3-bis(4-pyridyl)propane, bbi=1,4-bis(imidazol-1-yl)butane, bpz=3,3′,5,5′-tetramethyl-4,4′-bipyrazole), have been hydrothermally synthesized and structurally characterized. 1–8 display various coordination motifs with different entangled forms and conformations due to the effect of the assistant N-donor ligands. The photoluminescent properties of compounds 1–8 in solid state were studied. Interestingly, 3 exhibits highly efficient luminescent sensing for Cu2+ cations and CrO42- anions, as well as detection ability for the different organic solvents and nitro explosives. These results indicated that it could be utilized as a multi-responsive luminescent sensor. Furthermore, compound 3 also shows good chemical resistance to both acidity and alkalinity solutions with pH ranging from 2 to 13. Thus, multi-photofunctionality and fluorescent response to pH have been combined in the 3, which is the first example in the Zn-based hybrid materials.

Color-tunable entangled coordination polymers based on long flexible bis(imidazole) ligands and phenylenediacetate

Color-tunable coordination polymers with various types of entanglement have been synthesized from flexible phenylenediacetic acid and bis(imidazole) ligands.

A family of entangled coordination polymers constructed from a flexible bisimidazole ligand and versatile polycarboxylic acids: Syntheses, structures and properties

A family of entangled coordination polymers, namely, [Cd(cba)(ibpi)] (1), [Cd(sdc)(ibpi)]·H2O (2), [Cd2(bpdc)2(ibpi)2] (3), [Ni2(sdc)2(ibpi)2(H2O)2]·H2O (4), [Cd2(tdc)2(ibpi)]·H2O (5), [Cd(Hbtc)(ibpi)] (6), [Co2(tdc)2(ibpi)2·H2O]·2H2O (7) and [Cd2(cdc)2(ibpi)2]·2H2O (8). [ibpi=1-(4-(4-(1H-imidazol-1-yl)benzyloxy)phenyl)-1H-imidazole, H2cba=4,4′-carbonyldibenzoic acid, H2sdc=4,4′-sulfonyldibenzoic acid, H2bpdc=biphenyl-4,4′-dicarboxylic acid, H2cdc=1,4-cyclohexanedicarboxylic acid, H2tdc=thiophene-2,5-dicarboxyl acid, and H3btc=1,3,5-benzenetricarboxylic acid], have been synthesized and structurally characterized. Compound 1 exhibits a 2-fold parallel interpenetration of sql networks. Compound 2 presents a 3-fold parallel interpenetration of sql networks. Compound 3 features a parallel polycatenation of 3-fold interpenetrated sql networks. Compound 4 shows a unique type of inclined interpenetration of sql networks. Compound 5 displays a 3-fold interpenetration of pcu network. Compound 6 exhibits a uninodal self-catenating mab network. Compound 7 shows an 8-connected self-catenating framework of 8T10 topology with the point symbol (420·68). Compound 8 presents a unique 8-connected 8T21 self-catenating framework with the point symbol (424·64). The thermal stabilities and photochemical properties of compounds 1, 2, 3, 5, 6and8 have also been studied.

Syntheses and structures of three entangled coordination polymers based on the bifunctional ligand 4-((3-(pyridin-4-yl)-1H-pyrazol-1-yl)methyl)benzoic acid

Self-assembly of transition metal salts with long bifunctional ligand affords three entangled coordination frameworks, namely, [Co(ppmba)2] (1), [Zn(ppmba)2]·0.5H2O (2) and [Cd(ppmba)2]·0.25H2O (3) (Hppmba=4-((3-(pyridin-4-yl)-1H-pyrazol-1-yl)methyl)benzoic acid). Their structures were determined by single-crystal X-ray diffraction analyses and further characterized by element analyses, IR spectra, X-ray powder diffraction, and TG analyses. Compound 1 is a peculiar (2D→3D) interdigitated architecture that is assembled from bilayer motifs. Compounds 2 and 3 exhibit fascinating (2D→3D) entangled frameworks constructed from undulating 44-sql layers, which have both polycatenane and interdigitation characters. In addition, the magnetic properties of compound 1 and the photoluminescence properties of compounds 2 and 3 were studied.

Seven entangled coordination polymers assembled from triphenylamine-based bisimidazole and dicarboxylates: interpenetration, self-penetration and mixed entanglement

Seven entangled coordination polymers constructed from a triphenylamine-based bisimidazole and carboxylic acids have been synthesized and characterized.

Syntheses, structures and properties of five entangled coordination polymers constructed with trigonal N-donor ligands

Five new entangled coordination polymers, which are based on large trigonal N-donor ligands and polycarboxylates, are reported. They display different entangled nets with self-penetrating, polythreading, interdigitation and interpenetration features.

Lanthanide-based entangled coordination polymers connected by thiophene-2,5-dicarboxylate: solvothermal syntheses, crystal structures, luminescence and magnetic properties

Nine novel coordination polymers (CPs) with the formulas [M6(TDA)9(DEF)5(H2O)3]n [M = Ce (1), Pr (2), Nd (3), Sm (4)], [Eu4(TDA)6(DEF)3(H2O)2]n (5), [Gd2(TDA)3(DEF)2]n·H2O (6), [Tb2(TDA)3(DEF)2]n·0.5H2O (7), [Dy2(TDA)3(DEF)2]n·H2O (8) and [Yb2(TDA)3(DEF)2]n·0.5H2O (9) (TDA = 2,5-thiophenedicarboxylate anion and DEF = diethylformamide) have been synthesized at different temperatures in a DEF–H2O solvent system under solvothermal conditions. All the compounds were characterized by single crystal X-ray diffraction analysis (XRD), Fourier transformation vibrational spectroscopy (FT-IR) and thermal analysis (TGA). Structural analyses of CPs 1–4 reveal that the polymers crystallize in the orthorhombic space group Pna21 and form 3D frameworks with large volumes 10 378.1(5), 10 230.5(5), 10 171.9(5) and 10 077.1(11) A3, respectively. The M(III) ions of CPs 1–4 exhibit nine and eight coordination numbers with diverse geometries. Structural analyses of CPs 5 and 6–9 unveil that the polymers crystallize in the monoclinic system, with space groups P21 and P2/c, respectively, forming a 3D network. The TDA ligand exhibits two coordination modes [(κ1-κ1)–(κ1-κ1)-μ4 and (κ2-κ1-μ2)–(κ1-κ1)-μ5] which interconnect the metal ions to generate 3D novel metal–organic frameworks. The luminescence properties of 4, 5, 7 and 8, and the magnetic properties of 6–8 were investigated.

Rigidity versus Flexibility of Ligands in the Assembly of Entangled Coordination Polymers Based on Bi- and Tetra Carboxylates and N-Donor Ligands

Seven Zn(II) coordination polymers including [Zn(pbda)(p-bimb)]·H2O (1), [Zn(pbda)(bpa)0.5] (2), [Zn(pbda)(bpp)] (3), [Zn(Hpbda)2(bibm)2] (4), [Zn(pbta)0.5(m-bimb)]·H2O (5), [Zn(pbta)0.5(bpp)(H2O)] (6), and [Zn(H2pbta)(bibm)]·H2O (7) (H2pbda = 4,4′-{[1,4-phenylenebis(methylene)]bis(oxy)}dibenzoic acid; p-bimb = 1,4-bis(1H-imidazol-l-yl)methyl)benzene; bpa = 1,2-bis(4-pyridyl)ethane; bpp = 1,3-bis(4-pyridyl)-propane; bibm = 4,4′-di(1H-imidazol-1-yl)-1,1′-biphenyl; m-bimb = 1,3-bis(1H-imidazol-l-yl)methyl)-benzene; H4pbta = 5,5′-phenylenebis(methylene)-1,1′-3,3′-(benzene-tetracarboxylic acid) were prepared under solvothermal conditions and structurally characterized. Compound 1 shows a three-dimensional (3D) channel-like architecture constructed by helical chain subunits. Compound 2 shows a rare 2D + 2D + 2D → 2D network with both polyrotaxane and polycatenane features. 3 holds a 2D layer structure constituted of metal-sharing right- and left-handed helical chains. Compound 4 presents a one-dimensional (1D) chain which is decorated by long side arms around the chain. Compound 5 possesses a 2D wave-like layer formed by [Zn2(m-bimb)]n chains by linear pbta ligands. Compound 6 displays a 3D framework that is stabilized by hydrogen bonding interactions between the coordinated H2O molecules and the neighboring carboxylate oxygen atoms. Compound 7 possesses a 1D + 1D → 2D polycatenation motif. The results demonstrated that the rigidity versus flexibility of the ligands along with the number of carboxyl groups make an impact on the structural diversities of the entangled coordination polymers. Moreover, compounds 3 and 6 as representative examples possessed high catalytic efficiency for the photodecomposition of methyl blue in water using natural sunlight irradiation.

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.

A novel entangled coordination polymer presenting a 10-fold interpenetrating diamondoid network with unprecedented [5 + 5] mode

A novel coordination polymer [AgBF4(bocb)2] (1) (bocb=1,4-bis(4-oxy-1-cyano)benzene) has been synthesized. This compound exhibits a ten-fold diamondoid framework with an unusual [5+5] mode of interpenetration. Its luminescent property was also investigated.

A series of entangled coordination polymers assembled by a V-shaped bisimidazole ligand and various dicarboxylic acids: synthesis, characterization and luminescence properties

Based on a V-shaped bisimidazole ligand and various dicarboxylic acids, nine entangled coordination polymers, namely, [Zn(o-bdc)(bips)]·2H2O (1), [Zn2(cdc)2(bips)2]·2H2O (2), [Zn2(bpedc)2(bips)2] (3), [Zn(odc)(bips)]·H2O (4), [Zn2(sdc)2(bips)2]·5H2O (5), [Co2(sdc)2(bips)2(H2O)]·2H2O (6), [Cd2(bpdc)2(bips)2]·3H2O (7), [Cd2(2,6-ndc)2(bips)2(H2O)2]·2H2O (8) and [Cd(1,4-ndc)(bips)]·DMF·H2O (9) (bips = bis(4-imidazol-ylphenyl)sulfone, o-H2bdc = o-phenyldicarboxylic acid, H2cdc = 1,4-cyclohexanedicarboxylic acid, H2bpedc = 4,4′-stibenedicarboxylic acid, H2odc = 4,4′-oxybisbenzoic acid, H2sdc = 4,4′-sulfonyldibenzoic acid, H2bpdc = biphenyl-4,4′-dicarboxylic acid, 1,4-H2ndc = naphthalene-1,4-dicarboxylic acid, 2,6-H2ndc = naphthalene-1,4-dicarboxylic acid), have been synthesized and structurally characterized. Compound 1 exhibits a 2D → 2D polycatenane of 3-fold interpenetrated sql layers. Compound 2 shows a 2D → 3D polycatenane of 3-fold interpenetrated sql layers. Compound 3 displays a 2D → 3D polycatenane of 5-fold interpenetrated sql layers. Compound 4 exhibits a 2-fold interpenetration of CdSO4 networks. Compound 5 presents a 2D → 3D polycatenane by three-fold interpenetrated {42·63·8}2 layers. Compound 6 features an unusual 2D → 2D polycatenane framework assembled by the entanglement of sql layers containing 2-membered loops. Compound 7 exhibits a 1D → 3D polycatenane by the 3-fold interpenetration of 3-connected ribbons. Compound 8 displays a 3-fold interpenetration of SrAl2 networks. Compound 9 exhibits a 4-fold interpenetration of dia networks in a [2 + 2] mode. Their luminescence properties were also measured.