Resulting Coordination Polymer Research Articles

Loading of a coordination polymer nanobelt on a functional carbon fiber: a feasible strategy for visible-light-active and highly efficient coordination-polymer-based photocatalysts.

To improve the photocatalytic properties of coordination polymers under irradiation in the visible-light region, coordination polymer nanobelts (CPNB) were loaded on functional carbon fiber (FCF) through the use of a simple colloidal blending process. The resulting coordination polymer nanobelt loaded functional carbon fiber composite material (CPNB/FCF) exhibited dramatically improved photocatalytic activity for the degradation of rhodamine B (RhB) under visible-light irradiation. Optical and electrochemical methods illustrated the enhanced photocatalytic activity of CPNB/FCF originated from high separation efficiency of photogenerated electrons and holes on the interface of CPNB and FCF, which was produced by the synergy effect between them. In the composite material, the role of FCF could be described as photosensitizer and good electron transporter. For FCF, the number of functional groups on its surface has a significant influence on the photocatalytic performance of the resulting CPNB/FCF composite material, and an ideal FCF carrier was obtained as a highly efficient CPNB/FCF photocatalyst. CPNB/FCF showed outstanding stability during the degradation of rhodamine B (RhB); thus, the material is suitable for use as a photocatalyst in the treatment of organic dyes in water.

Distinct 3D CdII Coordination Polymers with 1,2-Naphthalenedicarboxylate Regulated by Dipyridyl Co-Ligands with Different Spacers

Two distinct three-dimensional (3D) CdII coordination polymers with 1,2-naphthalenedicarboxylate (ndc2–) and dipyridyl co-ligands have been synthesized under hydrothermal conditions. Interestingly, the slight difference in the two 4,4′-dipyridyl building blocks, namely, 1,2-bi(4-pyridyl)ethane (bpp) and 1,2-bi(4-pyridyl)ethene (bpe) with C–C or C=C spacers, results in the significant structural divergence of the resultant coordination polymers. Structural analysis reveals that complexes [Cd(ndc)(bpp)(H2O)]n (1) and {[Cd5(ndc)4(bpe)2(OH)2](H2O)1.5}n (2) are constructed by discrete metal–carboxylate dimeric units and metal–carboxylate chains, respectively, which are further extended by bpp or bpe linkers to form the inclined interpenetrated two-dimensional (2D)→3D network for 1 and the 3D porous framework for 2. This result reveals that the flexibility of auxiliary ligands plays an important role in the structural assemblies of coordination networks. The thermal and luminescence properties of both complexes were also investigated in solid state.

Tuning CuII Coordination Polymers Derived from a Bis(pyrazolecarboxylate) Ligand by Solvothermal C–H Bond Activation: Synthesis, Structures, Catalysis, and Magnetic Properties

AbstractA new bis(pyrazolecarboxylate) ligand, 1,3‐phenylenebis(1H‐pyrazole‐5‐carboxylic acid) (H2PBPC) has been synthesized to study the structure and intriguing properties of the resultant coordination polymers synthesized under solvothermal conditions. The reaction of H2PBPC with Cu(ClO4)2 in the presence of NaOH at two different temperatures (80 and 120 °C) resulted in two coordination polymers, namely, [{Cu2Na(H2OPBPC)}]∞ (1) and [{Cu4Na2(H2OPBPC)2}]∞ (2), which display 2D corrugated sheet and 3D staircase architectures, respectively; in these structures, the aromatic C–H bond flanked by the pyrazolecarboxylate moieties was oxidized to form a C–O bond. When 2,2′‐bipyridine (2,2′‐bpy) was used instead of NaOH, [{Cu2(2,2′‐bpy)2(H2PBPC)}(H2O)]∞ (3) formed, and such C–H bond activation was not observed. Interestingly, one of the coordination polymers, namely, 1, displayed catecholase and phosphatase activity. Variable‐temperature magnetic susceptibility data in the range 2–300 K showed that there is antiferromagnetic coupling between the metal centers of 1 and 2 that is mediated through the phenoxo and pyrazole bridges, whereas 3 revealed dominant ferromagnetic interactions between the bis(pyrazolato)‐bridged CuII centers owing to its very unusual Cu–N–N–Cu torsion angles of 75.28 and 69.52°.

Effect of substituent on dimensionality and properties in divalent metal isophthalate coordination polymers with a conformationally flexible dipyridylamide coligand

Hydrothermal reaction of divalent metal nitrates and 3-pyridylmethylnicotinamide (3-pmna) with either isophthalic acid (H2iph) or 5-nitroisophthalic acid (H2nip) has afforded a series of four coordination polymer solids that were structurally characterized via single-crystal X-ray crystallography. [Ni(iph)(3-pmna)]n (1) and [Cd(iph)(3-pmna)]n (2) both exhibit a {M2(OCO)2} dimer-based 1-D ribbon topology with metal–metal contacts bridged by both ip and 3-pmna ligands. [Ni(nip)(3-pmna)]n (3) has the same topology as its unsubstituted congener 1, showing a null effect on the part of the nip nitro group. On the other hand [Cd(nip)(3-pmna)]n (4) exhibits a {Cd2O2} dimer-based 2-D (4,4) layer topology, a rare example of the nitro group imposing a higher dimensionality in the resulting coordination polymer. While 2 showed strong blue–violet luminescence, quenching mechanisms due to the nitro group rendered 4 non-luminescent. Thermal properties of these new materials are also investigated.

Modulating the M II /Pyrimidine‐4,6‐dicarboxylato System by Metal, Solvent and Temperature Variation

We report herein the synthesis and physicochemical characterisation of seven new compounds employing divalent metal ions and pyrimidine-4,6-dicarboxylato ligand (pmdc): {[Cd(μ-pmdc)(H2O)3]·2H2O}n (1), [Cd(phen)(μ3-pmdc)]n (2), [Cd(μ5-pmdc)]n (3), {[Ca(μ3-pmdc)(H2O)3]·H2O}n (4), {[Mn(μ-pmdc)(form)(H2O)]·2H2O}n (5), [Cu(μ-pmdc)(DMSO)2]n (6), and {[Zn(μ-pmdc)(DMF)(H2O)]·DMF}n (7) (where phen = 1,10-phenanthroline, form = formamide, DMSO = dimethyl sulfoxide, DMF = dimethylformamide). These compounds are the result of three different approaches that share a common aim: to replace/eliminate coordination solvent molecules to force unusual coordination modes of pmdc that render MII-pmdc polymers with different structural motifs. To this end, we have employed either metal ions that permit high coordination numbers or organic aprotic solvents that can also act as terminal ligands, while different thermal treatments have been applied to both the reaction mixtures as well as solid compounds. The crystal structure of compound 1 contains zig-zag polymeric chains in which mer-[Cd(H2O)3]2+ units are sequentially joined by means of bis-chelating pmdc ligands. Compound 2 is made up of stacked neutral layers that are built up from the fusion of two independent centrosymmetric [Cd2(phen)2(μ3-pmdc)2] dinuclear units. Hydrothermal treatment at higher temperature led to compound 3, which presents a three-dimensional framework in which the pmdc ligand exhibits an unprecedented μ5-κ2N,O:κ2N′,O′:κO′:κO″:κO″′ coordination mode. Moreover, thermogravimetric and thermodiffractometric analyses of 1 have also provided access to an alternative route to obtain higher dimensional frameworks with crystal structures that differ from those crystallised in dissolution. Compound 4 consists of neutral 2D [Ca(μ3-pmdc)(H2O)3] sheets that are formed by the junction of calcium-pmdc chains through carboxylate oxygen bridges, exhibiting a herringbone pattern. On the other hand, formamide, dimethyl sulfoxide, and dimethylformamide have been employed in compounds 5–7 to evaluate their effect on the resulting coordination polymer. A common feature in these compounds is the one-dimensional structure displayed and the fact that at least one solvent molecule is coordinated to the metal atoms. Whereas the manganese and zinc compounds exhibit corrugated MII-pmdc chains, the copper compound adopts the more typical planar arrangement. The disposition of the chains of compounds 5–7 has been rationalised on the basis of the steric hindrance imposed by the coordination of the ligands, which determines the more stable geometrical isomer in each case.

Layered dipyridylamide coordination polymers from in situ lactonization of 2-carboxycinnamic acid

Hydrothermal reaction of divalent metal nitrates with 2-carboxycinnamic acid (H2cca) and 3-pyridylisonicotinamide (3-pina) caused in situ rearrangement of the acid precursor to the anionic lactone 1,3-dihydro-3-oxo-1-isobenzofuranacetate (dibf). This resulted in generation of a series of coordination polymer solids of the form [M(3-pina)2(dibf)2]n (M=Zn, 1; Cd, 2; Co, 3; Mn, 4; Ni, 5). Single-crystal X-ray diffraction revealed that 1–5 are isostructural, manifesting (4,4) grid motifs with capping dibf ligands. Use of the structurally related 3-(2-carboxyphenyl)propionic acid (H2cpp) as a precursor avoided any in situ rearrangement. Still, the resulting coordination polymer [Co(3-pina)2(Hcpp)2]n (6) shows a topology virtually identical to 1–5, but with protonated Hcpp carboxylate hydrogen bonding patterns within the grid apertures. Luminescence properties of the d10 derivatives 1 and 2 are also presented, along with thermal degradation behavior.

Poly[[chlorido(1,10-phenanthroline-κ2N,N′)copper(II)]-μ3-1,1,3,3-tetracyano-2-ethoxypropenido-κ3N:N′:N′′]: coordination polymer sheets linked into bilayers by hydrogen bonds

In the title compound, [Cu(C9H5N4O)Cl(C12H8N2)]n or [Cu(tcnoet)Cl(phen)]n, where phen is 1,10-phenanthroline and tcnoet is 1,1,3,3-tetracyano-2-ethoxypropenide, the axially elongated (4 + 2) coordination polyhedron around the Cu(II) centre contains N atoms from three different tcnoet ligands. The resulting coordination polymer takes the form of sheets which are linked in pairs by a single C-H...N hydrogen bond to form bilayers. The bond lengths provide evidence for significant bond fixation in the phen ligand and extensive electronic delocalization in the tcnoet ligand, where the two -C(CN)2 units are rotated, in conrotatory fashion, out of the plane of the central C3O fragment.

Complexation of Uranyl and Rare-Earth Ions by a Fluorinated Tetracarboxylate. Formation of a Layered Assembly and Three-Dimensional Frameworks

The reaction of uranyl and rare-earth nitrates with 4,4′-(1,1,1,3,3,3-hexafluoroisopropylidene)diphthalic acid (H4L) under hydro-/solvo-thermal conditions (2:1 water/acetonitrile at 180 °C) gives a series of complexes, most of which have been crystallographically characterized. In the lattice of the uranyl complex [(UO2)2(L)(H2O)2]·2H2O (1), the metal atoms are chelated by two adjacent carboxylate groups, each of the latter being bridging bidentate, and the resulting coordination polymer is two-dimensional. The ∼14 Å thick layers comprise two uranyl-covered faces linked to one another by L4– pillars, a claylike architecture likely due to the hydrophobic interactions between the organic ligands. The complexes [Ce(HL)(H2O)]·1.5H2O (2) and [Nd(HL)(H2O)]·2.5H2O (3) are isomorphous and they display a high degree of connectivity, with the metal atoms in ten- or eleven-coordinate environments being bound to five or six HL3– ligands. The three-dimensional (3D) framework formed contains one-dimensional subunits of adjacent metal ions with each coordination polyhedron sharing two triangular faces with its neighbors. The hydrophobic CF3 groups are oriented divergently from the exterior of wide channels (∼22 × 8 Å), which are occupied by the solvent water molecules. The complexes with rare-earth ions of smaller ionic radii, [M4(L)3(H2O)9]·7H2O with M = Er (4), Yb (5), and Y (6), are isomorphous to the previously reported terbium(III) complex, and they crystallize as 3D frameworks containing di- and tetra-nuclear subunits. In the visible region, only the uranyl and europium (and terbium) complexes display significant solid-state luminescence.

Crystal Engineering of FeII Spin Crossover Coordination Polymers Derived from Triazole or Tetrazole Ligands

The past decade has witnessed intense research activity in the area of Fe(II) spin crossover coordination polymers, which are structurally diverse and functionally intriguing materials. In this endeavor, a less exploited series of ligands have been selected among various N-donor triazole and tetrazole molecules. Developing conventions that allow the tailoring of such functional materials with predictable architecture and properties is an important objective and current interest in crystal engineering. However, detailed knowledge on the structure-property correlation is still scanty due to the small number of crystal structures of such compounds. The principal focus is to decipher the effect of various supramolecular factors such as intermolecular interactions, hydrogen bonding etc., on the resultant Fe(II) coordination polymers. This tutorial review aims at highlighting some of the developments of such structurally diverse and functionally intriguing 1D polymeric chains, 2D and 3D networks built from triazole or tetrazole ligands exhibiting fascinating spin crossover phenomena.

Coordination Polymers Based on Heterohexanuclear Rare Earth Complexes: Toward Independent Luminescence Brightness and Color Tuning

Reactions in solvothermal conditions between hexanuclear rare earth complexes and H2bdc, where H2bdc symbolizes terephthalic acid, lead to a family of monodimensional coordination polymers in which hexanuclear complexes act as metallic nodes. The hexanuclear cores can be either homometallic with general chemical formula [Ln6O(OH)8(NO3)6](2+) (Ln = Pr-Lu plus Y) or heterometallic with general chemical formula [Ln(6x)Ln'(6-6x)O(OH)8(NO3)6](2+) (Ln and Ln' = Pr-Lu plus Y). Whatever the hexanuclear entity is, the resulting coordination polymer is iso-structural to [Y6O(OH)8(NO3)2(bdc)(Hbdc)2·2NO3·H2bdc]∞, a coordination polymer that we have previously reported. The random distribution of the lanthanide ions over the six metallic sites of the hexanuclear entities is demonstrated by (89)Y solid state NMR, X-ray diffraction (XRD), and luminescent measurements. The luminescent and colorimetric properties of selected compounds that belong to this family have been studied. These studies demonstrate that some of these compounds exhibit very promising optical properties and that there are two ways of modulating the luminescent properties: (i) playing with the composition of the heterohexanuclear entities or (ii) playing with the relative ratio between two different hexanuclear entities. This enables the independent tuning of luminescence intensity and color.

Dipyridylamide isomer influenced dimensionality in luminescent cadmium phthalate coordination polymers with similar tetranuclear clusters and ribbon motifs

Hydrothermal reaction of cadmium nitrate, potassium hydrogen phthalate (KHphth), and either 4-pyridylnicotinamide (4-pna) or 3-pyridylisonicotinamide (3-pina) afforded two new luminescent coordination polymers with similar structural components but different dimensionality. {[Cd2(phth)2(4-pna)(H2O)]·0.25H2O}n (1, phth=phthalate) manifests [Cd4(phth)4(H2O)2] ribbons based on tetranuclear clusters, connected to two others by pairs of tethering 4-pna ligands to afford 4-connected 2D (4,4) layers. [Cd2(phth)2(3-pina)(H2O)]n (2) has similar tetranuclear clusters and [Cd4(phth)4(H2O)2] ribbons, which are linked to four others by 3-pina tethers to construct a 6-connected 3D 41263pcu network. Subtle differences in phth binding and bridging mode, along with changes in coordination environment, serve to influence the dimensionality of the resulting coordination polymer. Thermal decomposition behavior is also discussed.

Manganese(II)-promoted ligand oxidation during the formation of a coordination polymer

Abstract During the synthesis of Mn(II) compounds from fluorene-2,7-dicarboxylate, the ligand undergoes in situ oxidation to generate a Mn(II) coordination polymer with the ligand fluorenone-2,7-dicarboxylate (FODC2 −). It was demonstrated that the transformation occurs with dioxygen as reactant and Mn(II) as catalyst. The resulting coordination polymer, [Mn3(FODC)3(DMA)4]⋅2.5DMA, displays a 2D network based on the [Mn3(COO)6(DMA)4] unit with triple carboxylate bridges. Magnetic analyses were performed not only on temperature-variable susceptibility but also on field-variable magnetization, indicating weak antiferromagnetic interactions through the triple bridges.

Solvothermal synthesis, crystal structures and properties of two new magnesium coordination polymers of (l)-malic acid

Abstract Two new three dimensional magnesium coordination polymers of formula, [Mg 4 (HL-MA) 2 (HCO 2 ) 2 (OH) 2 ]∙(EtOH)∙2(H 2 O) ( 1 ), and [Mg(HL-MA)(H 2 O)] ( 2 ), (H 3 L-MA = l -malic acid) have been solvothermally synthesized in order to study the coordination properties of (L)-malic acid and the structural features of the resulting coordination polymers (CPs). The structures of the newly synthesized CPs have been determined by single-crystal X-ray diffraction analysis and further characterized by various analytical and spectroscopic techniques. The single crystal structure analysis showed that the complexes, 1 and 2 form three-dimensional frameworks. Topological analysis revealed that the 1 can be described as a new 4-nodal net with Schlafli symbol of {4 3 .6 2 .8}{4 3 }{4 7 .6 3 }{4 7 .6 5 .8 2 .10} and 2 can be described as a ‘ sra ’ net. The ligand acted as a bi-anionic hepta-dentate and bi-anionic penta-dentate in 1 and 2 respectively. Moreover, the solid-state luminescent spectra of the two Mg(II) complexes indicated that the two complexes emitted their own characteristic sensitized luminescence.

A Polyoxometalate‐Based Coordination Polymer with the Diamondoid Topology

AbstractThe new coordination polymer [ϵ‐PMo12O37(OH)3{La(H2O)3}4(L)]·28H2O [H4L = tetrakis(4‐carboxyphenyl)silane] can be synthesized by combining equal quantities of two types of 4‐connecting building blocks: organic L4– ligands and inorganic polyoxometalate‐derived [ϵ‐PMo12O37(OH)3{La(H2O)4}4]4+ polyoxocations. The resulting coordination polymer exhibits the diamondoid topology, where both building blocks act as pseudotetrahedral nodes. The structural and spectroscopic characteristics of the parent polyoxocation are retained in the coordination polymer.

Hydrate Isomerism in Coordination Polymers of Bismuth and Acetylenedicarboxylate

AbstractSingle crystals of $\rm^{2}_{\infty}$[Bi(ADC)2/4(ADC)3/3(H2O)2]·2H2O (P$\bar{1}$, Z = 2) and $\rm^{3}_{\infty}$[Bi(ADC)2/4(ADC)3/3(H2O)3]·H2O (P$\bar{1}$, Z = 2) were obtained by isothermal evaporation of aqueous solutions containing acetylenedicarboxylic acid (H2ADC) and Bi(NO3)3·5H2O. Their crystal structures were solved and refined from X‐ray single crystal data. They are hydrate isomers with respect to the central Bi3+ ion, which leads to completely different topologies of the resulting coordination polymers.

Counterion and Steric Effects in Self-Assembled HgX2–Thioether Coordination Polymers

A series of mercury dithioether coordination polymers were synthesized from mercury dihalides and rigid xylyl dithioethers containing methyl, t-butyl, and benzyl pendant groups (ligands 3a–c). The resulting coordination polymers were examined by X-ray crystallography. Changes in sterics surrounding mercury result in structures ranging from one-dimensional polymers (e.g., (3a·HgI2)∞, (3b·Hg2Cl4)∞, (3b·HgBr2)∞) to two-dimensional sheets (e.g., (3c·HgCl2)∞) and three-dimensional extended networks (e.g., [(3c)2(HgBr2)3]∞) from crystallizations which were conducted under identical conditions with the same 1:1 stoichiometry. Bridging mercury–halide bonds were found to play a surprisingly large role in governing the final structures.

Suppression of Realgar Cage Degradation during Complexation: Formation of Hybrid Coordination Polymers with As4S4, PAs3S3, and Cu(I) Halide Building Blocks

Realgar, As(4)S(4), reacts with Cr(CO)(5)THF under cage degradation to give As(4)S(3)·Cr(CO)(5) (1). The reverse structural change is found if solutions of 1 in CH(2)Cl(2) react with equimolar amounts of PAs(3)S(3)·W(CO)(5) and CuX (X = Cl, Br, I) in CH(3)CN under biphasic diffusion conditions. The resulting coordination polymers 2-4 contain a reconstituted realgar molecule along with the PAs(3)S(3) cage. The crystal structures of (CuX)(As(4)S(4))(PAs(3)S(3)) (X = Cl: 2; Br: 3) are characterized by one-dimensional (1D) (CuX)(As(4)S(4)) strands, which are formed by alternating As(4)S(4) cages and CuX dumbbells. Terminal PAs(3)S(3) molecules are coordinated to copper by apical phosphorus and bridging realgar through sulfur. The As(3) triangles of the resulting (CuX)(As(4)S(4))(PAs(3)S(3)) strands interact with halides of neighbored strands to give a folded three-dimensional (3D) network. The structure of (CuI)(3)(As(4)S(4))(PAs(3)S(3)) (4) contains 1D (Cu(3)I(3))(n) strands as backbones, which are bridged by sulfur atoms of two η(1:2)-As(4)S(4) molecules while PAs(3)S(3) confines the resulting sheet. The As(3) triangles at the surface of the layers interact with iodide of the next layer to form a layered 3D network.

Luminescent cadmium phenylenedipropionate coordination polymers with long-spanning dipyridine ligands

Hydrothermal synthesis has generated oxoanion-free divalent cadmium 1,4-phenylenedipropionate (phdp) coordination polymers containing either bis(4-pyridylmethyl)piperazine (bpmp) or bis(4-pyridylformyl)piperazine (bpfp) ligands. The coordination environment at cadmium appears to dictate the overall dimensionality of the resulting coordination polymer crystal structure. {[Cd(phdp)(bpfp)(H 2O)]·4H 2O} n ( 1) possesses pentagonal bipyramidal coordination at cadmium with trans pyridyl donors and displays a simple 2-D (4,4) grid network. {[Cd(phdp)(bpmp)]·5H 2O} n ( 2) exhibits distorted octahedral coordination with cis pyridyl donors, resulting in a 3-D 3-fold interpenetrated diamondoid network. Both 1 and 2 show visible-light luminescence upon ultraviolet excitation, with the emission maximum depending on the nature of the dipyridyl coligand.

Facile synthesis of zinc(ii)-carboxylate coordination polymer particles and their luminescent, biocompatible and antibacterial properties

Four different morphologies, including 1D nanobelts (1), 3D nanorod-flowers (2), fan-like (3) and rhombus-like (4) architectures have been synthesized from the mild reaction of Zn(Ac)2·2H2O and 2,2′-bipyridine-4,4′-dicarboxylic acid (H2L). The shape of the resulting coordination polymer particles (CPPs) was dependent on the amount of solvent and the molar ratio of reactants used in the reaction. In the experimental process, some additives such as triethylamine and acetic acid played a vital role in the formation of CPPs as means of adjusting the deprotonation rate of the organic linker (H2L), and thus affected the morphology of the resulting CPPs. We also investigated the effect of the different morphologies on the luminescent properties and bioactivities.

Tuning of unusual secondary ligands to construct fluorescent zinc coordination polymers of an unsymmetrical pyridylbenzoate ligand from 1D chain to interdigital or porous 2D layers and interpenetrated 3D frameworks

Four dicarboxylic acids and nitrilotriacetic acid as secondary ligands have been used to tune the zinc(II)-organic frameworks constructed by an unsymmetrical pyridylbenzoate ligand, 3-pyrid-4-ylbenzoic acid (HL1). Interestingly, malonic acid (H2L2), nitrilotriacetic acid (H3L3), and succinic acid (H2L4), not coordinating to the metal centers and not even existing in the resultant coordination polymers can, however, tune the coordinating modes of L1 and zinc ions, and then the frameworks of their coordination polymers from interdigital 2D layers of [Zn5(L1)10(H2O)3.5]n (1), to porous 2D distorted square grids of [Zn(L1)2(H2O)1.5]n (2), and 4-fold interpenetrated 3D diamond networks of [Zn(L1)2]n (3), respectively. Especially, the topology of 1 displays an unprecedented (3,4)-connected 2D trilayer net with the Schlafli symbol of (62.8)2(6.84.10). For 2, there are 0.7 × 0.8 nm2 1D channels hosting water molecules. Besides, pimelic acids (H2L5) act as bridges for zinc dimeric constructing units and terminers for the 1D chain constructed by dimeric nodes and antiparallel double L1 spacers for [Zn2(L1)2(L5)]n (4). By contrast, terephthalic acids (H2L6) acting as bridges link similar 1D chains in 4 to construct interdigital 2D layers for [Zn2(L1)2(L6)]n (5). Finally, these five coordination polymers all exhibit strong fluorescent emissions at room temperature and high thermal stabilities.