Heterometallic Coordination Polymers Research Articles

Visible light photocatalytic performance of Co/Ag bimetallic coordination polymer catalysts designed from hard and soft acid-base theory

Heterometallic coordination polymers have promising applications in photocatalysis, and the design and selection of suitable organic ligands and coordination metals is the key to improve the catalytic activity of polymer photocatalysts. Herein, a novel Co/Ag bimetallic coordination photocatalyst, designed based on the hard and soft acid-base (HSAB) theory, has been successfully prepared by a stepwise method with Ag-S coordination as the main component and Co-N/Co-S as the complementary component. The obtained Co/Ag photocatalyst demonstrates excellent performance in the photocatalytic degradation (visible light) of halogenated phenolic pollutants. Degradation of 10 ppm of 4-chlorophenol could reach 100 % in 4 h, and 70 % degradation of 4-fluorophenol, which is even more difficult to degrade, could also be achieved. In addition, hydrogen production experiments conducted under visible light irradiation showed that the hydrogen production could reach 36.95 μmol h−1 g−1 for 6 h, which strongly demonstrated the excellent reduction ability of Co/Ag photocatalysts. The photocatalyst exhibits enhanced photocatalytic activity which is ascribed to the formation of Ag-S and Co-N/Co-S coordination, which greatly increases the charge density and facilitates charge transfer. Thus, the photogenerated electrons can induce both the conversion of O2 to •O2- for oxidation reactions, as well as the direct attack of the C-Cl bond for reduction reactions. This study demonstrates the successful design of the synergistic Co/Ag bimetallic coordination photocatalysts based on the HSAB theory, thereby offering a promising research avenue for the fabrication of heterometallic coordination photocatalysts.

Structural characterization of a new samarium–sodium heterometallic coordination polymer

Lanthanide-containing materials are of interest in the field of crystal engineering because of their unique properties and distinct structure types. In this context, a new samarium–sodium heterometallic coordination polymer, poly[tetrakis(μ2-2-formyl-6-methoxyphenolato)samarium(III)sodium(I)], {[SmNa(C8H7O3)4]·solvent} n (Sm-1), was synthesized and crystallized via slow evaporation from a mixture of ethanol and acetonitrile. The compound features alternating SmIII and NaI ions, which are linked by ortho-vanillin (o-vanillin) ligands to form a mono-periodic chain-like coordination polymer. The chains propagate along the [001] direction. Residual electron density of disordered solvent molecules in the void space could not be reasonably modeled, thus the SQUEEZE function was applied. The structural, vibrational, and optical properties are reported.

Dual emissive Ln(iii)–Ag(i) heterometallic chains based on tris(2-pyridyl)phosphine oxide

Tris(2-pyridyl)phosphine oxide has been successfully used to assemble novel 1D Ln(iii)–Ag(i) heterometallic coordination polymers demonstrating dual emission behavior and excitation wavelength dependent photoluminescence.

The application of Na-Bi MOF as a heterometallic coordination polymer and 2,2-dimethoxypropane as an in-situ-generating ternary solvent for the extraction and preconcentration of some phthalate and adipate esters from tap, well, surface, and river water samples

In this study, the first-ever attempt was done to apply a heterometallic metal–organic framework (MOF) called Na-Bi MOF for the extraction and preconcentration of some phthalate and adipate esters. Also for the first time, 2,2-dimethoxypropane was adopted as an efficient in-situ generating ternary solvent for the desorption aim. Diverse real samples including tap, well, surface, and river waters underwent the developed extraction procedure. For performing the process of extraction, only 5 mg of Na-Bi MOF was added into a sodium sulfate-enriched aqueous solution containing the target compounds and vortexed. So, the analytes were adsorbed onto the MOF particles. Centrifugation separated the analyte-loaded MOF from the aqueous solution. The MOF was treated with only 500 µL of 2,2-dimethoxypropane. By centrifugation, the organic phase was separated and subjected to evaporation using a gas splitter device. After the complete evaporation of the organic phase, only 5 µL of 1,2-dibromoethane was applied for the elution of the inner perimeter of the conical bottom glass test tube by vortexing. Eventually, two microliters of the organic phase were injected into a gas chromatograph equipped with flame ionization detection. High enrichment factors (520–800), satisfactory extraction recoveries (52–80 %), low limits of detection and quantification (0.66–1.20 and 2.18–3.97 µg/L, respectively), favorable relative recoveries without dilution (86–117 %), wide linear ranges (3.97–500 µg/L), and high coefficients of determination (0.9903–0.9944) were recorded for the developed method. Low amount use of the MOF and organic solvents, diversity of real samples, no need for dilution, and short chromatographic run (a quarter) are the highlights of the developed method.

Synthesis, structure characterization, and properties of a new heterometallic coordination polymer containing two μ3-bridging tridentate ligands

Synthesis, structure characterization, and properties of a new heterometallic coordination polymer containing two μ3-bridging tridentate ligands

Statement of Retraction: Synthesis and anti-breast cancer activity on osteogenic sarcoma of a in/Na heterometallic coordination polymer

Statement of Retraction: Synthesis and anti-breast cancer activity on osteogenic sarcoma of a in/Na heterometallic coordination polymer

Three Ca(II)-Dy(III) heterometallic coordination polymers with different topologies and different water clusters: Synthesis and properties

Three new heterometallic polymers [DyL4Ca2(H2O)2.5(C2H5OH)0.5]·Him·H2O (1), [Dy2L6Ca3(H2O)12]·6H2O (2) and [Dy0.67L2Ca(H2O)2]·4H2O (3) (H2L = 4-chloropyridine-2,6-dicarboxylic acid, im = imidazole) were prepared under solvothermal conditions. The single crystal determination showed that polymers 1 and 3 are two-dimensional structures and polymer 2 is three-dimensional structure. It was found that different types of water clusters were present in these three polymers. They exhibit different topologies with the topological symbols {43}2{46·66·83}, {42·6·123}2{42·6}2 and {63}, where polymer 2 is a new topological type. A series of characterizations, such as XRD, IR, TGA, and solid-state fluorescence, were carried out on these three crystalline materials. They all show characteristic emission spectra of Dy(III) ions. Their quantum yields Фtotal are 4.01% (1), 2.25% (2), 2.88% (3), respectively.

High Proton Conductivity of Magnetically Ordered 2D Oxalate-Bridged [MnIICrIII] Coordination Polymers with Irregular Topology.

Two heterometallic coordination polymers {[NH(CH3)2(C2H5)]8[Mn4Cl4Cr4(C2O4)12]}n (1) and {[NH(CH3)-(C2H5)2]8[Mn4Cl4Cr4(C2O4)12]}n (2) were obtained by slow evaporation of an aqueous solution containing the building block [A]3[Cr(C2O4)3] [A = (CH3)2(C2H5)NH+ or (CH3)(C2H5)2NH+] and MnCl2·2H2O. The isostructural compounds comprise irregular two-dimensional (2D) oxalate-bridged anionic layers [Mn4Cl4Cr4(C2O4)12]n8n- with a Shubnikov plane net fes topology designated as (4·82), interleaved by the hydrogen-bonded templating cations (CH3)2(C2H5)NH+ (1) or (CH3)(C2H5)2NH+ (2). They exhibit remarkable humidity-sensing properties and very high proton conductivity at room temperature [1.60 × 10-3 (Ω·cm)-1 at 90% relative humidity (RH) of 1 and 9.6 × 10-4 (Ω·cm)-1 at 94% RH of 2]. The layered structure facilitates the uptake of water molecules, which contributes to the enhancement of proton conductivity at high RH. The better proton transport observed in 1 compared to that in 2 can be tentatively attributed to the higher hydrophilicity of the cations (CH3)2(C2H5)NH+, which is closely related to their affinity for water molecules. The original topology of the anionic networks in both compounds leads to the development of interesting magnetic phases upon cooling. The magnetically ordered ground state can be described as the coupling of ferromagnetic spin chains in which Mn2+ and Cr3+ ions are bridged by bis(bidentate) oxalate groups into antiferromagnetic planes through monodentate-bidentate oxalate bridges in the layers, which are triggered to long-range order below temperature 4.45 K via weaker interlayer interactions.

Two temperature-dependent 2D heterometallic Cd(II)–Dy(III) coordination polymers exhibiting slow magnetic relaxation and luminescence properties

Two unique two-dimensional (2D) Cd(II)–Dy(III) heterometallic coordination polymers, {[DyCd(HPMA)(PMA)2(H2O)4]·2H2O}n (1) and [DyCd(PAA)(PMA)2(H2O)3]n (2, PAA– = phenylacetate), were prepared successfully based on the phenylmalonic acid (H2PMA). The construction of two polymers is sensitive to the reaction temperature and can be synthesized directionally at room temperature and 90 °C, respectively. Complexes 1 and 2 display 2D layer structures that include dinuclear [Dy2] cluster node and Dy(III)-based 1D zigzag chain motif severally. The Dy(III)-based units in two structures both are spaced well with the adjacent ones by the diamagnetic Cd(II)-based moieties. The magnetic studies reveal that 1 and 2 both display slow magnetic relaxation with temperature-dependent relaxation peaks producing an effective energy barrier (Δτ) of 74.5 and 32.1 K, separately. Furthermore, the solid-state photophysical properties of 1 and 2 show strong characteristic luminescent emissions of Dy(III) ion in the visible region.

Anion-Induced Structural Diversity and Optical Chromism in a Series of Cyano-Bridged Heterometallic 3d-4f Coordination Polymers.

The self-assembly reaction of the neutral dicyano-bis(1,10-phenanthroline) iron(II) complex with lanthanide ions (Ln = Eu(III), Gd(III), Er(III)) provided two different classes of heterometallic cyano-bridged 3d-4f architectures depending on the nature of the counteranion, irrespective of the size of the 4f metal ion. Tetranuclear oligomers with a squared Fe2Ln2 core were isolated when using nitrate salts, whereas unusual 1D polymeric chains were obtained when resorting to triflate salts under the same synthetic conditions. It is shown that the different structural motifs have a remarkable impact on the thermal stability and the optical properties of the compounds, which display a notable optical ipsochromism of the parent Fe(II) complex upon coordination with the Ln ion. This effect is significantly more pronounced in the polymeric chain than in the Fe2Ln2 oligomer both in solution and in the solid state. Structural evidence suggests that this behavior is likely related to the geometry of the CN-Ln bridge. On the other hand, more extended π-stacking interactions in the oligomer give rise to a broad charge-transfer absorption (600-1500 nm), making this compound promising as NIR absorber. Density Functional Theory calculations and electrochemical studies demonstrate that the observed negative chromism originates from the stabilization of a mixed metal/cyanide character HOMO with respect to a phenanthroline-centered LUMO.

Tunable structures and magnetic / optical properties of six Cd(II)-based coordination polymers by introducing different para- or dia-magnetic metal ions

One monometallic and five heterometallic coordination polymers (HCPs) based on homophthalic acid (H2HPA), [Cd2(HPA)2(H2O)2]·H2O (1), [CdMn(HPA)2(H2O)2]·H2O (2), [Cd3Co(HPA)4(H2O)4]·2H2O (3), [CdCo(HPA)2(DMSO)(H2O)2] (4), [CdNa2(HPA)2(μ2-H2O)(H2O)] (5) and [Cd2Na2(HPA)3(μ2-H2O)(H2O)2] (6), were synthesized solvothermally. Complexes 1-3 have similar two-dimensional (2D) layer structures except that all or part six-coordinated Cd(II) ions in 1 were replaced by the six-coordinated Mn(II) or Co (II) ion in 2 and 3, respectively. Complex 4 shows an 1D ladderlike structure, and 5 and 6 exhibit different 2D layer structures. The different structures of 3/4 and 5/6 could be assembled directly by controlling the different pH values with other same reaction conditions, respectively. Magnetic studies reveal that the introducing of para-magnetic Mn(II) and Co(II) ions endow antiferromagnetic interarions between the neigboring spins in 2–4, and 2 with isotropic Mn(II) ion displays a significant cryogenic magnetocaloric effect with a maximum −ΔSm value of 19.29 J K−1 kg−1 at 2 K and ΔH = 7 T. In addition, the solid-state photophysical properties of 1, 5 and 6 display blue emissions centered at ca. 453 nm, 448 nm and 428 nm, respectively.

Incorporation of Switchable Inorganic Building Blocks into Heterometallic Coordination Polymers

A new terpyridine-based ligand with a pyridyl-1,2,4-triazoyl bidentate pocket “out the back” has been used to synthesize monometallic CoII, FeII, and RuII complexes where the octahedral metal is bound in a N6 bis-terpyridine coordination sphere. All four complexes ([MII(Lpyrtz-tpy)2](X)2 where MII = FeII, RuII, CoII with X = BF4–, or MII = CoII with X = PF6–) were structurally characterized confirming the expected bis-terpyridine coordination sphere. The monometallic complexes all show reversible MII/III redox processes, while the CoII complexes also undergo a slow spin crossover over the temperature range 50 K – 350 K. Utilizing the free triazole-pyridine bidentate pocket we show the ability of these complexes to act as supramolecular building blocks able to form 1D and 2D coordination polymers, {[MIIMI(Lpyrtz-tpy)2(MeCN)m]X3}n, with MI being CuI or AgI metal ions, MII = CoII, FeII, or RuII, X = BF4 or PF6, and m = 0 or 1, all five of which were structurally characterized.

A new 3D heterometallic coordination polymer: luminescent property and nursing application value on acute cerebral infarction

ABSTRACT With the solvothermal reactions of flexible tetracarboxylic acid ligand with the Cd(II) and Ca(II) ions, we acquired a new heterometallic coordination polymer formulated as {[Cd2Ca2(L)2(DMF)2(H2O)7]·(DMF)·2(H2O)}n (1, H4L is 5-(bis(4-carboxybenzyl)amino)isophthalic acid, DMF is N,N’-Dimethylformamide). Furthermore, the solids of 1 shows ligand-centered luminescence at room temperature. It not only evaluated the treatment and nursing application value on acute cerebral infarction, but also explored the related mechanism. Above of all, ELISA assay measured the content of the MMP-9 released into the cerebrospinal fluid, and the real time RT-PCR was implemented and the NF-κB activation in the brain tissue was measured.

Synergistic Effect of FeII and MnII Ions in Cyano-Bridged Heterometallic Coordination Polymers on Catalytic Selectivity of Benzene Oxygenation to Phenol

A cyano-bridged heterometallic coordination polymer with partial deficiencies of CN- ligands, [MnII(H2O)8/3]3/2[FeII(CN)5(NH3)], forms open metal sites both on MnII and FeII ions by liberation of monodentate ligands such as NH3 and H2O. [MnII(H2O)8/3]3/2[FeII(CN)5(NH3)] exhibits high catalytic activity and selectivity of benzene oxygenation to phenol in the presence of m-chloroperoxybenzoic acid as an oxidant. The postcatalytic spectroscopy of [MnII(H2O)8/3]3/2[FeII(CN)5(NH3)] and catalysis comparison with a physical mixture of [MnII(H2O)3]2[FeII(CN)6] and [Fe(H2O)3/2]4/3[Fe(CN)6], which has open metal sites on both MnII and Fe ions separately, indicated that the high activity resulted from high oxidation ability and phenol adsorption ability of FeII and MnII ions, respectively.

Simpler is better: A heterometallic (Mn-Na) metal organic framework (MOF) with a rare myc topology synthesized from bench chemicals for selective adsorption and separation of organic dyes

A low cost heterometallic (Mn-Na) coordination polymer with rare myc topology is designed and exploited for cationic dye adsorption selectivity and separation. • A low cost new heterometallic ( Mn-Na ) metal organic framework (MOF) is synthesized. • The crystallography reveals presence of two metal ions in the asymmetric unit i.e, Mn and Na. • Topological analysis shows a rare myc topology of the MOF which is very uncommon among the coordination polymers. • The resulting Mn-Na shows excellent selectivity, in the aqueous phase, for adsorption and separation of cationic dye, methylene blue (MB) with adsorption capacity to be 46.22 mg g −1 . • The present material showed excellent structural stability and recyclability with pseudo-second-order kinetics for adsorption. • The plausible mechanism suggests that HSAB concept is responsible for the adsorption process. The present work summarizes the design of a new heterometallic ( Mn-Na ) metal organic framework (MOF) synthesized under solvothermal conditions. The single crystal X-Ray analysis uncovers its composition as [MnNa(HCOO) 3 ] n . The crystallography reveals the presence of two metal ions in the asymmetric unit i.e., Mn and Na which are connected through a bridging formate ligand. Both Mn(II) and Na(I) are coordinated by six oxygen atoms thus forming a distorted octahedral geometry around each metal ion. The HCOO - ligand acts as a bridge to propagate the structure along the three axis resulting in a 3D MOF. Each oxygen of the formate is coordinated to both Mn and Na. Topological analysis shows a rare myc topology of the MOF which is very uncommon among the coordination polymers reported so far. The resulting Mn-Na shows excellent selectivity, in the aqueous phase, for adsorption and separation of cationic dye, methylene blue (MB) with an adsorption capacity to be 46.22 mg g −1 . Moreover, this adsorbent material showed excellent structural stability and recyclability; and the pseudo-second-order kinetics for adsorption. The plausible mechanism suggests that the HSAB concept is responsible for the adsorption process. Hard donors of dye molecules build strong interactions with hard Na + ions embedded in MOF. Thus, the designed MOF is the first example in heterometallic MOF chemistry to show dye adsorption and is established as a simple, easy to prepare and low-cost polymer for environmental protection for future endeavours.

Insight into ground-state spin arrangement and bipartite entanglement of the polymeric coordination compound [Dy[formula omitted]Cu[formula omitted]][formula omitted] through the symmetric spin-1/2 Ising–Heisenberg orthogonal-dimer chain

The ground-state spin arrangement and the bipartite entanglement within Cu2+-Cu2+ dimers across the magnetization process of the 4f-3d heterometallic coordination polymer [Dy(hfac)2(CH3OH)2Cu(dmg)(Hdmg)2]n (H2dmg = dimethylglyoxime, Hhfac = 1,1,1,5,5,5-hexafluoropentane-2,4-dione) are theoretically examined using the symmetric isotropic spin-1/2 Ising–Heisenberg orthogonal-dimer chain. The numerical results point to five possible ground states of the compound with three different degrees of the quantum entanglement within Cu2+-Cu2+. Besides the standard ferrimagnetic and saturated phases without quantum entanglement of Cu2+ ions, which are manifested in low-temperature magnetization curve as wide plateaus at the non-saturated magnetization 16.26μB and at the saturation value 20.82μB, respectively, one also finds an intriguing singlet-like phase with just partial entanglement within Cu2+-Cu2+ and two singlet phases with fully entangled Cu2+-Cu2+ dimers. The former quantum phase can be identified in the low-temperature magnetization process as very narrow intermediate plateau at the magnetization 9.27μB per unit cell, while the latter ones as zero magnetization plateau and intermediate plateau at the magnetization 18.54μB. Non-monotonous temperature variations of the concurrence, through which the entanglement within cooper dimers is quantified, point to the possible temporary thermal activation of the entangled states of Cu2+-Cu2+ also above non-entangled ferrimagnetic and saturated phases.

Fresh hetero-metallic compound as luminescent sensor for detection of CS2 and inhibitory activity on children diabetes.

The combination of the dicarboxylate ligand of 2-aminoterephthalic acid (H2L), Cd(NO3)2·4H2O, and KNO3 under hydrothermal condition formed a fresh hetero-metallic coordination polymer, namely, [CdK2(L)2(H2O)4]n (1). The compound exhibited a high luminescence intensity at normal environment as well as high sensitivity and selectivity in the measurement of CS2. The effect of the fresh compound on childhood diabetes was investigated. A blood glucose monitor was utilized to assess the blood glucose level of the body after the addition of the compound. Moreover, the relative expression level of the insulin recipient on hepatocytes was assessed by real time RT-PCR.

Heterometallic Dual-Liganded AE-Ln-CPs Luminescent Probes for Efficient Sensing of Fe(III) Ions.

Iron ion is widely present in the environment and in biological systems, and are indispensable trace elements in living organisms, so development of an efficient and simple sensor for sensing Fe(III) ions has attracted much attention. Here, six heterometallic AE-Ln coordination polymers (CPs) [Ln2 (pda)4(Hnda)2Ca2(H2O)2]·MeOH (Ln = Eu (1), Tb (2); H2pda = 2,6-pyridinedicarboxylic acid, H2nda = 2,3-naphthalenedicarboxylic acid), [Ln (pda)2 (nda)AE2(HCOO)(H2O)] (AE = Sr, Ln = Eu (3), Tb (4); AE = Ba, Ln = Eu (5), Tb (6)) with two-dimensional (2D) layer structures were synthesized by hydrothermal method. All of them were characterized by elemental analysis, XRD, IR, TG, as well as single crystal X-ray diffraction. They all show infinite 2D network structure, where complexes 1 and 2 are triclinic with space group of , while 3-6 belong to the monoclinic system, space group P21/n . The solid-state fluorescence lifetimes of complexes 1, 3 and 5 are τobs1 = 1930.94, 2049.48 and 2,413.04 µs, respectively, and the quantum yields Ф total are 63.01, 60.61, 87.39%, respectively, which are higher than those of complexes 2, 4 and 6. Complexes 1-6 all exhibited efficient fluorescence quenching response to Fe3+ ions in water, and were not interfered by the following metal ions: Cu2+, Cd2+, Mg2+, Ni2+, Co2+, Ca2+, Ba2+, Sr2+, Li+, Na+, K+, Al3+, Fe2+, Pb2+, Cr3+, Mn2+ and Zn2+. The quenching coefficient K SV for complexes 1-6 is 1.41 × 105 M−1, 7.10 × 104 M−1, 1.70 × 105 M−1, 1.57 × 105 M−1, 9.37 × 104 M−1, 1.27 × 105 M−1, respectively. The fluorescence quenching mechanism of these complexes towards Fe3+ ions was also investigated. It is possible that the weak interaction formed between the complexes and the Fe3+ ions reduce the energy transfer from the ligand to the Ln3+ ion, producing the emission burst effect. This suggests that complexes 1-6 can be candidate for efficient luminescent sensor of Fe3+.

Syntheses, crystal structures and photophysical properties of Ni/Co-Ln coordination polymers

Fourteen isomorphic heterometallic coordination polymers (CPs) with general formulas of {[LnM(2,3-pydc)2(ox)0.5(H2O)3]·3H2O}n (M = Ni, Ln = Pr 1, Nd 2, Sm 3, Eu 4, Gd 5, Tb 6, Dy 7; M = Co, Ln = Pr 8, Nd 9, Sm 10, Eu 11, Gd 12, Tb 13, Dy 14; 2,3-pydc2– = fully deprotonated pyridine-2,3-dicarboxylic acid, ox2– = fully deprotonated oxalic acid) have been synthesized by hydrothermal methods. All the CPs crystallize in triclinic P-1 space group and exhibit a 3D network formed by 2,3-pydc2– and ox2– bridging Ln(III) and Ni(II)/Co(II) ions. Meamwhile the room temperature photoluminescent properties have been explored. Except for CPs 5 and 12, the other CPs exhibit characteristic luminescence of Ln(III) ions.

Heterobimetallic three-dimensional 4d-4f coordination polymers based on 5-methyl-1-(pyridyn-4-ylmethyl)-1H-1,2,3-triazole-3,4-dicarboxylate

Three novel 4f-4d heterometallic coordination polymers (CPs), [Ln(H2O)3CdL2(NO3)]·6H2O (L ​= ​ethyl 5-methyl-1-(pyridin-4-ylmethyl)-1H-1,2,3-triazole-3,4-dicarboxylate; Ln ​= ​Eu, Gd, Tb 1, 2 and 3, respectively) have been successfully synthesized by hydrothermal treatment and slow cooling-down crystallization. These CPs have been structurally characterized by single-crystal X-ray diffraction. 1–3 are isostructural and consist of a three-dimensional network showing channels. The networks are reinforced via hydrogen bonds and π-π stacking interactions. The crystal topology analysis shows an infinite 2D layer topology with net symbol {4,4} (sql). The magnetic behavior of these compounds is explained by the expected contribution of almost isolated Ln (III) ions. An energy gap of 375 ​cm−1 between the 7F0 ground state and the first excited state of compound 1 has been deduced from magnetic data showing an excellent agreement with the spectroscopic data.