Structure Of Coordination Polymer Research Articles

Competition in formation of stimuli-responsive metallogel and coordination polymers from a single precursor: synthesis, characterization and catalytic application

The synthesis, structure, and catalytic properties of a new 2D crystalline coordination polymer (Zn-CP1) as well as a stable new low molecular weight metallogel (Zn-G1) are reported. Interestingly, both types of materials can be synthesized using the same amino acid based chiral ligand (PV) and Zn2+ ion. Precisely, pure organic solvent (MeOH) prompts gelation while DMF-water medium favours the formation of coordination polymer (CP). Hence, the nature of the solvents and metal counter anion used, play a crucial role in gel formation. Both the CP and gel were characterized by various spectroscopic and analytical techniques such as PXRD, FT-IR, TGA, SEM, and dynamic rheology. Structural analysis of Zn-G1 reveals an entangled spongy-like fibrous network in which spongy patches consist of micro fibres within the matrix of the supramolecular metallogel, while the structural analysis of Zn-CP1 revealed the formation of a 2D sheet-like structure. The Zn-G1 exhibits remarkable stimuli-responsive behaviour towards temperature, mechanical force, and chemicals; however, the Zn-CP1 was found to exhibit promising catalytic activity over Zn-G1 for the conversion of CO2 to cyclic carbonate from various epoxides.

Synthesis, characterization and crystal structures of heteronuclear coordination polymers with 4-methylpyridine

Synthesis, characterization and crystal structures of heteronuclear coordination polymers with 4-methylpyridine

Anisotropic Thermal Expansion of Structurally Related Lanthanide-Mercury(II) Cyanide Coordination Polymers.

Three sets of related lanthanide-mercury(II) cyanide coordination polymers were synthesized by the reaction of LnCl3·xH2O (Ln = Ce, Nd, Eu, Gd, Tb, Dy, Ho, Tm, Yb, and Lu) with Hg(CN)2 and structurally characterized. [Ce(OH2)5][Hg(CN)2Cl]3·2H2O is a 3-D material with sheet-based architecture; its thermal expansion behavior shows uniaxial negative thermal expansion (-18.3(8), 39(2), and 68.3(16) ppm K-1 along the a, b, and c axes, respectively). This anisotropic thermal behavior is postulated to be driven elastically by weak Hg···Cl interactions: large area expansion of the sheets causes negative thermal expansion in the perpendicular direction. Using lanthanides heavier than Ce yielded 2-D sheet-based compounds with the formula [Ln(OH2)x]2[Hg(CN)2]5Cl6·2H2O (Ln = Nd and Eu, x = 7; Ln = Gd, Tb, Dy, Ho, Tm, Yb, and Lu, x = 6). Although there was also evidence for elastic behavior within these materials, both showed uniaxial zero thermal expansion (Ln = Nd: 27.9(17), 22.4(10), and 0.6(12) ppm K-1 along the I, II, and III principal axes, respectively; Ln = Tb: 39.6(12), 1.1(17), and 36.1(7) ppm K-1 along the a, b, and c axes, respectively). Despite their similar structural architecture, this zero thermal expansion was found to occur in different directions─within the plane of the 2-D sheets for [Nd(OH2)7]2[Hg(CN)2]5Cl6·2H2O but in the direction perpendicular to the 2-D sheets for [Tb(OH2)6]2[Hg(CN)2]5Cl6·2H2O. Overall, this system of compounds reveals the delicate relationship between coordination polymer structure and thermal expansion.

Synthesis and structure of two-dimensional coordination polymer based on 2,2′-bithiophene-5,5′-dicarboxylic acid

Synthesis and structure of two-dimensional coordination polymer based on 2,2′-bithiophene-5,5′-dicarboxylic acid

Introduction of manganese-iron phosphide as hydrogen evolution reaction electrocatalyst based on their poly aspartic acid complexes

Electrocatalysts play an important role in water splitting into hydrogen and oxygen, resulting in a clean and sustainable source of hydrogen energy. However, to make this process affordable and efficient, electrocatalysts that are highly active and low-cost are necessary. This study describes the use of poly aspartic acid ligand to coordinate the metal ions Fe3+ and Mn2+, which are then precipitated, carbonized, and phosphorized to create MnFe/P/C coordination polymer structures. These structures serve as electrocatalysts for HER and exhibit effective activity, with an overpotential of 143 mV at the current density of 10 mA/cm2 and a Tafel slope of 58.4 mVdec−1. This performance surpasses that of oxide electrocatalysts. The high surface area of the MnFe/P/C nanocomposite contributes to its durability and efficiency. This study suggests that using transition metals and amino acids to construct electrocatalysts could lead to further advancements in HER electrocatalysts.

1D Mn coordination polymer derived from sulfanilic acid: Synthesis, structure, adsorption properties and Hirshfeld surfaces analysis

A one-dimensional Mn coordination polymer formulated; [Mn2(C6H7NO3S)2Cl4O4]n (1) (where = C6H7NO3S is sulfanilic acid) was synthesized via the hydrothermal method by reacting aqueous solutions of MnCl2·4H2O and sulfanilic acid. The X-ray studies demonstrate layered arrangement of monomers in the coordination polymer interconnected by weak hydrogen bonds. The vibrational frequencies of functional groups and bonds within the polymer were analyzed using infrared spectroscopy. The thermal degradation of the coordination polymer structure was studied under non-isothermal conditions in an argon atmosphere using thermogravimetric (TG) and differential thermal analysis (DTA), revealing a decomposition process occurring in four to five distinct stages. The sorption properties of the coordination polymer were investigated using N2 gas in an Autosorb IQ device at 77 K, resulting in a surface area of 318.4642 m²/g. Additionally, the sorption behavior of benzene and water vapor on the polymer was investigated at room temperature, yielding a result of 70.82 m²/g for benzene vapor and 172.66 m²/g for water vapor. The molecular fragment, [Mn2(C6H7NO3S)2Cl4O4] as the monomer unit are used for calculating the Hirshfeld surface of this compound that reveals strong N-H∙∙∙Cl intermolecular hydrogen bonding and π–π interactions.

Cage-like Cu5Cs4-Phenylsilsesquioxanes: Synthesis, Supramolecular Structures, and Catalytic Activity.

A small family of nonanuclear Cu5Cs4-based phenylsilsesquioxanes 1-2 were prepared by a convenient self-assembly approach and characterized by X-ray diffraction studies. The compounds 1 and 2 show some unprecedented structural features such as the presence of a [Ph14Si14O28]14- silsesquioxane ligand and a CuII5CsI4 nuclearity in which the metal cations occupy unusual positions within the cluster. Copper ions are "wrapped" into a silsesquioxane matrix, while cesium ions are located in external positions. This resulted in cesium-involved aggregation of coordination polymer structures. Both compounds 1 and 2 realize specific metallocene (cesium-phenyl) linkage between neighboring cages. Compound 2 is evaluated as a catalyst in the Baeyer-Villiger (B-V) oxidation of cyclohexanone and tandem cyclohexane oxidation/B-V oxidation of cyclohexanone with m-chloroperoxybenzoic acid (mCPBA) as an oxidant, in an aqueous acetonitrile medium, and HNO3 as the promoter. A quantitative yield of ε-caprolactone was achieved under conventional heating at 50 °C for 4 h or MW irradiation for 30 min (for cyclohexanone as substrate); 17 and 19% yields of lactone upon MW irradiation at 80 °C for 30 min and heating at 50 °C for 4 h, respectively (for cyclohexane as a substrate), were achieved. Complex 2 was evaluated as a catalyst for the oxidation of alkanes to alkyl hydroperoxides and alcohols to ketones with peroxides at 60 °C in acetonitrile. The maximum yield of cyclohexane oxidation products was 30%. Complex 2 exhibits high activity in the oxidation of alcohols.

Catalytic activation of persulfate by 3D Cd(II) coordination polymers based on a flexible cyclotriphosphazene-functionalized ligand

Dye removal in wastewater can be done by catalytic reaction with coordination polymers. Herein, Two 3D Cd(II) coordination polymers, namely, {[Cd3(L)(H2O)4].(H2O)(DMF)}n (GTU-1) and {[Cd3(L)(4,4-bpy))(H2O)2].(H2O)}n (GTU-2), were prepared with a novel hexapod-shaped molecular building block, hexakis(methyl-2-(4-phenoxyphenyl)acetatebenzene) cyclotriphosphazene (H6L), by solvothermal reactions in dimethylformamide with nitric acid as the modulator. Cd(II) coordination polymers were characterized by Fourier transform infrared spectroscopy, thermal analysis, scanning electron microscopy, powder X-ray diffraction analysis and single crystal X-ray diffraction technique. GTU-1 represents a 3D pillared-layered coordination polymer structure containing 2D Cd-carboxylate (Cd(COO)n)-based inorganic building unit (IBU) whereas GTU-2 is a 3D coordination polymer derived from 1D IBU bridged together by deprotonated L6- and judiciously chosen ancillary linker 4,4-bipyridine (4,4-bpy). In both complexes, the flexible multisite cyclotriphosphazene bridging ligand (H6L) is completely deprotonated. GTU-2 exhibited relatively good catalytic activity towards rhodamine B (RhB), Methylen Blue (MB) and Acid Red 17 (AR-17) removal in aqueous solution.

Synthesis, Structure, and Spectroscopic Properties of Luminescent Coordination Polymers Based on the 2,5-Dimethoxyterephthalate Linker

We report on the synthesis and the crystal structure of the solvent-free coordination polymer CoII(2,5-DMT) (1) with 2,5-DMT ≡ 2,5-dimethoxyterephthalate which is isostructural to the already reported MnII and ZnII congeners (C2/c, Z = 4). In contrast, for M = MgII, a MOF with DMF-filled pores is obtained, namely Mg2(2,5-DMT)2(DMF)2 (2) (P1¯, Z = 2). Attempts to remove these solvent molecules to record a gas sorption isotherm did not lead to meaningful results. In a comparative study, the thermal (DSC/TGA) and luminescence properties of all the four compounds were investigated. The compounds of the MII(2,5-DMT) composition show high thermal stability up to more than 300 °C, with the ZnII compound having the lowest decomposition temperature. MII(2,5-DMT) with MII = MnII, ZnII and 2 show a bright luminescence upon blue light irradiation (λ = 405 nm), whereas CoII in 1 quenches the emission. While ZnII in ZnII(2,5-DMT) and MgII in 2 do not significantly influence the (blue) emission and excitation bands compared to the free 2,5-DMT ligand, MnII in MnII(2,5-DMT) shows an additional metal-centred red emission.

Synthesis, Structure, and Property of Noncentrosymmetrical Coordination Polymer Based on Mixed Functional Ligands and Zinc Ions

Synthesis, Structure, and Property of Noncentrosymmetrical Coordination Polymer Based on Mixed Functional Ligands and Zinc Ions

Structure and Magnetic Properties of Pseudo-1D Chromium Thiolate Coordination Polymers

The synthesis, structure, and magnetic properties of two novel, pseudo-one-dimensional (1D) chromium thiolate coordination polymers (CPs), CrBTT and Cr2BDT3, are reported. The structures of these materials were determined using X-ray powder diffraction revealing highly symmetric 1D chains embedded within a CP framework. The magnetic coupling of this chain system was measured by SQUID magnetometry, revealing a switch from antiferromagnetic to ferromagnetic behavior dictated by the angular geometrical constraints within the CP scaffold consistent with the Goodenough-Kanamori-Anderson rules. Intrachain magnetic coupling constants JNN of -32.0 and +5.7 K were found for CrBTT and Cr2BDT3, respectively, using the 1D Bonner-Fisher model of magnetism. The band structure of these materials has also been examined by optical spectroscopy and density functional theory calculations revealing semiconducting behavior. Our findings here demonstrate how CP scaffolds can support idealized low-dimensional structural motifs and dictate magnetic interactions through tuning of geometry and inter-spin couplings.

Smart sensing device for formaldehyde that based on uniform lanthanide CPs microsphere

Formaldehyde is toxic to human body and animals, thus sensing of low concention of formaldehyde is urgent. A new uniform luminescent and stable lanthanide microsphere of europium complex sensor (Eu-MTFBA) towards formaldehyde in water is developed. Single crystal analysis shows the microsphere has a one dimensional (1D) coordination polymer structure. The sensor was further molded into smart detection device of test paper, which is applied to detect formaldehyde through naked eyes. Furthermore, the sensing mechanism is also revealed by luminescence lifetimes measurement.

Front Cover: Metal Doping and Ligand Engineering as Tools for Tailoring the Electronic Structure of Coordination Polymers and their Oxygen Evolution Electrocatalytic Activity (Eur. J. Inorg. Chem. 5/2023)

The Front Cover shows the process of water oxidation to molecular oxygen, which is fundamental for providing electrons and protons for the generation of renewable fuels, electrocatalyzed by coordination polymers (CPs), under basic conditions. The two key components of CPs, namely the metal coordination complexes (orange octahedrons) and the organic linkers, whose suitable selection and engineering are crucial for rationally optimizing their catalytic performance, are evidenced. A thorough understanding of the structure-activity relationships and reaction mechanism underpins the development of electrocatalysts with ever-improving performance for possible large-scale applications. We would like to thank Leonardo Tensi for designing and creating the cover graphic that fully captures the essence of the Review. More information can be found in the Review by G. Menendez Rodriguez and A. Macchioni.

Syntheses, Structural Insight and HirshFeld Surface Analysis of Two Heteroleptic Coordination Polymer of Cu(II)

Using a solvothermal method, we have synthesized two coordination polymers of Cu(II). One is a 1D polymer {[Cu(bpy)(NDC)(H 2 O)].2H 2 O} n (1, 1D) formed with 1,8-naphthalene dicarboxylic acid (H 2 NDC) and 2,2′ -bipyridine (bpy) as an auxiliary ligand, while the other is a 2D polymer {[Cu 3 (TMA)(Imd) 3 ].5H 2 O.2DMF} n (2, 2D) formed with trimellitic acid (H 3TMA) and imidazole (Imd) as an auxiliary ligand. Both coordination polymers 1 and 2 were formed through an in situ hydrolytic ring opening reaction of 1,8-naphthalic anhydride and trimelitic anhydride with bipyridine and imidazole ligands, respectively. The asymmetric unit of polymer 1 contains asymmetric η 1 binding mode (one of the carboxylate) linking distorted square-pyramidal [Cu(NDC)(bpy)(H 2 O)] 2+ coordination units. The syn-syn-η 1 :η 1 linear polymer conformation exist in the 1D coordination polymer with adjacent Cu…Cu distance is 6.849Å. A chain of cyclic tetrameric water clusters is present between the stacked layers of the 3D supramolecular structure. The formation of the 3D supramolecular structure is guided by various weak interactions such as OH…O, CH…O, CH…π and π…π interactions. The coordination polymers 2 forms 3D supramolecular architecture guided by various weak interactions such as OH…O, CH…O and NH…O interactions. The crystal structures of both coordination polymers have been determined using single crystal X-ray diffraction and their structural features are described.

Metal Doping and Ligand Engineering as Tools for Tailoring the Electronic Structure of Coordination Polymers and their Oxygen Evolution Electrocatalytic Activity

AbstractElectrocatalytic production of fuels [green hydrogen from water, C1‐high energy molecules from CO2, NAD(P)H from NAD(P)+], utilizing renewable energy sources, has in the oxygen evolution reaction (OER) its Achilles’ heel. Among the catalysts developed for facilitating OER, those based on coordination polymers (CPs) are attracting considerable interest due to their simplicity of preparation and modularity. In this review, after having recalled the key‐parameters that have to be considered when evaluating and benchmarking electrocatalysts, it is shown how the performance of CP‐based OER catalysts can be rationally improved by a) the suitable selection of the metal ion combination and b) engineering CPs with appropriate organic linkers. It is inferred that the catalytic effect of adding a different metal ion, than that of the CP structure (metal doping), occurs through an indirect alteration of the electronic features of the active metal center, which might be described by considering the energy of the d‐band with respect to that of the Fermi level (Ed), the eg occupancy or the metal ionic electronegativity (MIE). In rare cases, it is assumed that the added metal center can directly and synergistically participate at the catalytic process. The much less explored strategy b) to improve the performance of OER electrocatalysts, by properly engineering organic linkers, is related not only to an alteration of the electron density (acidity) of the metal center but also to a modification of the electron localization and conductivity of CPs.

The syntheses, structural and biological studies of Co(II) complexes of 1,2-Bis(pyridin-4-yl)ethane with 2-aminobenzene-1,4-disulfonic acid and 2,6-pyridinedicarboxylic acid

The newly synthesized salt named 4,4′-(ethane-1,2-diyl)bis(pyridin-1-ium) 2-aminobenzene-1,4-disulfonate, (H2BPE)2+(ADSA)2− (1), was prepared from the reaction of 1,2–bis(pyridin–4–yl)ethane (BPE) and 2–amino-benzene–1,4–disulfonic acid (H2ADSA). Two new metal complexes of 4,4′-(ethane-1,2-diyl)bis(pyridin-1-ium) 2-aminobenzene-1,4-disulfonate were also synthesized: The first complex [Co(BPE)2(H2O)4](ADSA).BPE (2) has been synthesized from the obtained proton transfer salt (1). The second complex, {[Co(BPE)(H2O)4]}n[Co(DPC)2].2H2O (4), is a one–dimensional coordination polymer and was synthesized using proton transfer salt (H2BPE)2+(DPC)2- (3). Elemental analysis, Nuclear Magnetic Resonance, Infrared and Ultraviolet–Visible spectra methods were used to elucidate the structure of 1. Elemental analysis, magnetic moment measurements, spectral (UV–Vis, AAS and IR) and X–ray crystallographic analysis were applied for structural manalysis of 2 and 4. X–ray crystallographic study for 2 and 4 revealed that in both complexes the BPE coordinated the Co(II). In compound 2, the coordination periphery of the Co(II) consists of two nitrogens from two BPE, four oxygens from four H2O molecules and forms the six–coordinated octahedral geometry. X–ray crystallographic analysis of 4 showed that the complex was polymer and the metal ions were linked by BPE ligand bridges. The molecular structure of coordination polymer 4 contains both cationic and anionic complexes, each with an octahedral geometry. The coordination sphere of the cationic complex consists of two nitrogens of two BPE and four oxygens of four aqua molecules. On the other hand, the two DPC2− ligands contribute two nitrogens and four oxygens to the coordination sphere of the anionic complex. The antibacterial and antifungal capabilities of the produced compounds were further investigated, and the MIC (Minimum Inhibitory Concentration) values were compared to those of related control substances.

Metal-to-ligand ratio-controlled assembly of two Ca(II) complexes: Synthesis, structures, reactant-induced reversible transformation, and catalytic properties

Hydrothermal reactions of Ca(NO3)2·4H2O and topiroxostat with different metal-to-ligand ratios yielded two new complexes {[Ca2(L)2(H2O)6]·H2O}n (1) and Ca(HL)2(H2O)4 (2) [H2L = 4-(3-(pyridine-4-yl)-1H-1,2,4-triazol-5-yl)picolinic acid], involving ligand in situ formation by hydrolysis of topiroxostat. X-ray structural analysis revealed that complex 1 has a 1D coordination polymeric structure while complex 2 displays a 0D discrete molecule. Both complexes exhibit interesting reactant-induced reversible structural transformation properties. Thermogravimetric analysis and temperature-dependent PXRD patterns indicated that the network of 1 keep high thermal stability up to 400 °C. The catalytic performance of the complexes for the solvent-free ring-opening polymerization of ε-caprolactone has been investigated.

Synthesis, structure, and electrochemical properties of a novel coordination polymer based on a nitrogen-rich ligand

Coordination polymers (CPs) are a kind of inorganic-organic hybrid materials that have received increasing attention recently due to their high porosity, stability, and modifiability. In this work, we have successfully synthesized a new CP based on a N-rich ligand (4,5-di(1H-tetrazol-5-yl)-2H-1,2,3-triazole) under hydrothermal condition. The crystal structure was determined by single-crystal X-ray diffraction. Compound 1 displays a three-dimensional supramolecular structure constructed from the two-dimensional layers, and has been further characterized by powder X-ray diffraction, elemental analysis, infrared spectrum, and thermogravimetric analysis. The electrochemical properties of compound 1 have been studied in detail. The detection performance of compound 1 modified electrodes was determined. The results reveal that compound 1 can be successfully applied as an electrode material to simultaneously detect two heavy-metal ions Cd2+ and Pb2+ with high sensitivity and selectivity. Moreover, compound 1 reveals excellent reversible capacity, cycle stability, and rate performance as an anode material for lithium-ion battery.

The synthesis and crystal structure of novel coordination polymers of cadmium(II) with hexamethylenetetramine ligand

The synthesis and crystal structure of novel coordination polymers of cadmium(II) with hexamethylenetetramine ligand

Synthesis, X-ray crystal structure of Cu(II) 1D coordination Polymer: In View of Hirshfeld surface, FMO, Molecular electrostatic potential (MEP) and Natural Bond orbital (NBO) analyses

A dynamic area in the realm of contemporary scientific research is the synthesis of molecular systems that exhibit binding abilities for the creation of effective coordination polymeric structures. In addition to the varied network architecture, the rational design and synthesis of metal-organic coordination polymers is currently of great interest because these extended polymeric systems are vital to numerous fields of modern research. In this present research, a new 1D coordination polymer of Cu(II) complex [Cu2(mPzA)2(Bz)]n (1) has been synthesized using two different ligands i.e. 5-methyl-pyrazole-3-carboxylic acid (mPzA) and benzoic acid (Bz). X-ray crystallography study reveals that in the solid-state structure of the title complex, Cu(II) exhibits distorted trigonal bipyramidal geometry. Quantum chemical calculations using density functional theory (DFT) method have been carried out for the complex 1. The computed results further support the experimental findings of the complex adopting a square pyramidal geometry. In the basal plane, the copper atom is bonded through two nitrogen atoms and two oxygen atoms which are bridged between two copper atoms. The axial position is occupied by the oxygen atom of a carboxyl group. Frontier molecular orbital analysis using the global reactivity parameters demonstrates the compound to be stable and less reactive. Moreover, molecular electrostatic potential (MEP) is evaluated using the electron density of the compound to predict the reactive sites. The MEP map clearly indicates strong electrophonic reaction potential of this complex. Natural bond orbital (NBO) analysis has been performed to check the hyperconjugation and thereby stability of the complex 1. NBO analysis revealed the charge delocalization from the bridging oxygen atoms towards copper atoms. The Hirshfeld surface analysis demonstrates absence of π…πstacking interaction and significant contribution of H···H (39.7%) and O···H (24.1%) interactions in building the supramolecular crystal packing.