Copper-based Coordination Polymer Research Articles

Fabrication of second auxiliary ligand-induced copper-based coordination polymers as urease inhibitors

Urease inhibitors (UIs) can improve soil nutrients, reduce soil nitrogen loss, increase nitrate nitrogen content, and help soil maintain nutrients. Because the already available inhibitors were harmful and inefficient, it was critical to develop and manufacture a new family of UIs with high efficiency. In this paper, two copper-based coordination polymers (Cu-CPs) were prepared and served as UIs, which showed that the Cu-CPs had good inhibitory effects on urease and the inhibitory rates were 0.83 ± 0.01 μM and 4.22 ± 0.51 μM. The kinetics of the UIs were determined that the Cu-CPs were anti-competitive inhibition modes with corresponding dissociation constants Ki of 1.52 μM and 5.32 μM. The results of molecular docking show that the two series of active compounds have obvious binding effect on the active site of urease. Furthermore, the oxygen atoms of –COO and μ2-OH groups play critical roles in urease inhibition action.

Fabrication of Substituent-Regulated Two-Dimensional Copper-Based Coordination Polymers as Urease Inhibitors

Fabrication of Substituent-Regulated Two-Dimensional Copper-Based Coordination Polymers as Urease Inhibitors

Dimensional Crossover and Proton Conductivity in Copper-Based Coordination Polymers by Coordinative Guest Insertion

Dimensional Crossover and Proton Conductivity in Copper-Based Coordination Polymers by Coordinative Guest Insertion

Water-stable Cu-based coordination polymer for ratiometric fluorescence detection of riboflavin

Riboflavin was first isolated from milk and widely used in food, biological and pharmaceutical fields. Accurate detection of riboflavin content is of great significance for the treatment of related diseases and the supervision of food/drug quality. In this paper, a 1D chain copper-based coordination polymer with excellent water stability was synthesized by hydrothermal method using rigid ligand 1,10-phenanthroline and flexible ligand 1,4-phenylenedioxydiacetic acid, named Cu-phen-PEDA. Based on the Förster resonance energy transfer (FRET) and dynamic quenching detection mechanism, the emission spectrum of Cu-phen-PEDA overlaps with the absorption spectrum of riboflavin. As an energy donor in this case, Cu-phen-PEDA significantly increases the fluorescence intensity of riboflavin (energy acceptor), while simultaneously decreasing its own fluorescence intensity, which is an effective proportional-building strategy. In the lower concentration range, riboflavin can be specifically recognized by ratiometric fluorescence with a good linear relationship, and the detection limit is as low as 23 nM. The potential aspects of its specificity, stability, reusability and practical application were explored.

Influence of bridging atoms in copper-based coordination polymers for enhancing urease inhibition activity

By using different O-donor second auxiliary ligands, we have designed and synthesized two Cu-based CPs with different bridging atoms to operate as urease inhibitors which show excellent urease inhibitory activity.

Stepwise Growth of Copper-Based Coordination Polymer on α-MnO2 Nanorods for Sustainable Reduction of Nitroarenes

Metal oxide/coordination polymer composites have gained great attraction due to their synergistic effects to increase their efficiency in various fields. In this work, a Cu-based coordination polymer (Cu-CP) was grown on the surface of α-MnO2 nanorods via stepwise assembly of benzene-1,4-dicarboxylic acid (H2BDC) as a ligand and a Cu(II) ion as a metal center. Comprehensive characterization techniques confirmed the successful growth of Cu-CP on the surface of α-MnO2 without affecting the morphology of pristine α-MnO2 nanorods. The obtained nanocomposite (α-MnO2/Cu-CP) revealed outstanding activity in the catalytic reduction of nitroarenes to aminoarenes under mild reaction conditions and afforded wide substrate applicability (more than 99% for nitrobenzene and 70–99% for other substituted nitroarenes during 1 h at room temperature). Importantly, α-MnO2/Cu-CP served as a better catalyst than bare α-MnO2 and Cu-CP due to the synergistic effects between building components. In addition, α-MnO2/Cu-CP was easily separable by centrifugation and its catalytic activity remained unaffected over five cycles. The use of water as a sustainable and green solvent and non-toxic and inexpensive metals used for the synthesis of the catalyst along with easy recovery and stability of the catalyst make the present protocol economical and sustainable. The time-dependent reduction kinetics followed pseudo-first-order kinetics with respect to the substrates.

Cu(II)-based coordination polymer encapsulated formate: Unveiling efficient photocatalytic degradation of Rose Bengal dye and remarkable sensing of DMF, acetone and acetonitrile

In this work, we have designed a new copper based coordination polymer (CP), {[Cu5(Bimb)10(H2O)2(HCOO)2]·(H2O)16(HCOO)8}n (KA@CP-S2) (Bimb = 1,4-bis[(1H-imidazol-1-yl)methyl]benzene) for the degradation of organic dyes and detection of small organic solvents. KA@CP-S2 has a two-dimensional (2D)network structure.4-connected uninodal 2D sqltopologyis depicted by KA@CP-S2with the point symbol of (44.62).KS@CP-S2exhibits effectivephoto-catalyst for the degradation of harmful dyes with degradation efficiencies of 97.7% (Rose Bengal), 95.8% (Bromophenol Blue) and 94.8%(Congo Red)from aqueous solutions under exposure of visible sun light.Importantly, sensing measurements shows that KS@CP-S2 can be employed as a luminescent sensor for accurately and consistently detectingof DMF, Acetone and CH3CNamong various solvents. The fluorescence quenching pathway for the solvent was established by the spectral overlap and nature of Stern-Volmer plots. Their stability and recyclability after sensing measurements are found to be excellent. The potentialdetection limits for DMF, Acetone and CH3CN was determined to be as low as 0.037, 0.027, 0.014 vol%, respectively.

Coordination-Induced NIR Photothermal Conversion and Laser Detonation Based on a Quasi-Diamond Interpenetrated Structure

In this work, a copper-based coordination polymer of [Cu3(dhba)2(OH)2(H2O)4] (Cu-dhba, H2dhba = 3,5-dinitro-4-hydroxybenzoic acid) has been constructed by the crystal-engineering approach, featuring a three-dimensional quasi-diamond interpenetrated structure. Impressively, due to the introduction of the d–d transition of the Cu2+ ion, Cu-dhba shows a broad absorption band with the maximum centered at the NIR section. As a result, Cu-dhba exhibits a remarkable photothermal conversion performance under 808 nm light; the temperature of the sample surface could be increased up to 115 °C within seconds. Benefiting from its high structure density and abundant hydrogen-bonding interactions, Cu-dhba shows no obvious performance decay after several photothermal cycling experiments. Moreover, due to the high density of energetic nitro groups periodically confined in its structure, Cu-dhba exhibits a drastic explosion under 808 nm laser irradiation, making Cu-dhba a promising laser-responsive energetic material.

A bioinspired copper-based coordination polymer for the detection of pheochromocytoma biomarkers

Oxidase-mimicking (catechol oxidase/laccase) nanozymes provide outstanding specificity in the detection of epinephrine (Epi) for the assessment of pheochromocytoma; however, epinephrine (Epi) and norepinephrine (NE) co-existing in the same systems will reduce the selectivity of the biosensor. In the current study, we synthesized copper-based coordination polymer (Cu-CP) nanozymes capable of accelerating the oxidation of Epi with high specificity. Furthermore, the Cu-CP is able to detect Epi over a wide linear range of 0.5–100 μM with a low detection limit of 0.36 μM while providing excellent stability and recyclability. Furthermore, we employed colorimetric and fluorescence signals for sequential detection of the coexistence of Epi and NE for use in tracking the treatment outcomes of patients with pheochromocytoma. Experiments using artificial urine further confirmed the efficacy of the proposed system.

Controlling pore size and interlayer space by ring rotation and electron-withdrawing effects in a 2D MOF

The 1D polymer chain, Cu(L1)BDC(Cl)2 constructed from copper(II) and 2,2′-(1H-imidazole-4,5-diyl)di-1,4,5,6-tetrahydropyrimidine (H-L1), reacts with terephthalic acid (H2BDC) to form a hydrogen-bonded 2D layered framework. Three hydrogen-bonded isoreticular 2D copper-based coordination polymers were constructed using different BDC analogues. Control of the pore size and interlayer distance was achieved by using different electron-withdrawing groups on the BDC linker. The reaction of Cu(L1)(Cl)2 with the perfluorinated terephthalic acid analogue, resulted in Cu(L1)BDC-F4. This showed a six-time shorter gas adsorption time with only a slight increase in the channel size between the layers. The pore volume of Cu(L1)BDC-F4 increased three times after modification of rotated tetrafluoro substituted aryl rings. The Cu(L1)BDC-Br and Cu(L1)BDC-NO2 analogues increased the interlayer distance of the hydrogen-bonded 2D coordination polymers. The Cu(L1)BDC family was characterized by PXRD, SCXRD, TGA, FT-IR, etc.

Two Cu(I\II) Coordination Polymers for Photocatalytic Degradation of Organic Dyes and Efficient Detection of Fe3+ Ions

In this work, two new copper-based coordination polymers (CPs), {[CuI(H2PO4)(dpe)]5(dpe)0.5(H2O)7}n (Cu-dpe(I)) and {[CuII(HPO4)(dpe)(H2O)](H2O)3}n (Cu-dpe(II)) (dpe = 1,2-di(4-pyridyl)ethylene), had been successfully constructed by hydrothermal method and solvent evaporation method, respectively, and their crystal structures were determined by single crystal X-ray diffraction. The differences of structure and properties between these two coordination polymers were discussed. The synthetic temperature caused their structure differences. They both exhibit excellent photocatalytic activity toward the degradation of methylene blue (MB) under visible light. The degradation rates of Cu-dpe(I) and Cu-dpe(II) to MB in 120 min under visible light were 88.1% and 97.2%, respectively. Some active free radicals such as ·OH, ·O2−, e− played an important role in degradation of MB. In addition, luminescent experiment revealed Cu-dpe(I) exhibits a relatively high sensitive and selective detection of Fe3+ ions in water solution via fluorescence quenching which was caused by competitive absorption of excitation wavelength energy between Fe3+ and Cu-dpe(I).Graphical Abstract

Copper-based coordination polymer as a fast and efficient dye adsorbent from aqueous solutions

Green synthesis of a copper-based coordination polymer (Cu-CP) is reported utilizing a simple precipitation method. The prepared coordination polymer was characterized and used as a potent adsorbent for the elimination of organic dyes from aqueous solutions. The results of zeta potential analysis showed that the surface charge of the Cu-CP was −33.6 mV. In spite of negative surface charge and moderate specific surface area (99 m2·g−1), the prepared Cu-CP was a good adsorbent for removal of cationic e.g., malachite green (MG) and methylene blue (MB) as well as an anionic dye e.g., Congo red (CR). This efficiency could be attributed to π-π interaction and hydrogen bonding between adsorbent and adsorbate as the major forces leading to uptake of the dyes. However, MG with high removal efficiency (85.44%) at 2 min was chosen as a targeted dye for further consideration. Then, the effect of various parameters for adsorption of the MG e.g., adsorbent amount, pH, and initial concentration of dye were optimized. The adsorption isotherm and kinetic model for MG adsorption were also investigated. Finally, the adsorbent was reused after recycling which indicated high MG removal efficiency in successive tests.

Alumina beads decorated copper-based coordination polymer particle filter for commercial indoor air cleaner

This paper provided an insight into the dual functionalities of air filter for the removal of multiple volatile organic compounds (VOCs) and Escherichia coli (E. coli) pathogen pollutants. In this regard, a cost-effective and eco-friendly method was developed to grow copper coordination polymer particles (Cu-CPP) onto porous alumina (Al2O3) support, resulting in the formation of Cu-CPP /Al2O3 composite beads. The use of coordination polymer particles can allow more control of the physical and chemical properties of the adsorptive materials at a molecular level through rational selection of metal nodes and organic ligands. Notably, excellent toluene adsorption capacities (256.97 mg g−1) and breakthrough behaviors were observed in Cu-CPP/Al2O3 beads. For the first time, the Cu-CPP/Al2O3 beads air filter was successfully scaled up and installed on a commercial air cleaner with 1 m3 test chamber for various VOCs adsorption. The Cu-CPP/Al2O3 beads air filter exhibited removal efficiency for formaldehyde (99.5%), toluene (99.5%), acetic acid (100%) and ammonia (100%), which are superior to conventional activated carbon. The E. coli was chosen as a model for testing the inactivation performance. The Cu-CPP/Al2O3 beads showed an efficiency of 97.02%, which was substantially higher than that of activated carbon (43.78%) after 120 min of exposure. This research paves the way for the development of multifunctional air filters based on copper coordination polymer particles, which would be excellent for commercial indoor air cleaner applications.

A copper-based coordination polymer formed through synergistic bridging of 1,2,4-triazole and acetate anions: synthesis, crystal structure and magnetic properties

A Cu(II) coordination polymer, [Cu2(pztrz)2(μ-CH3COO)(CH3COO)]·3H2O (1), derived from mono-substituted 1,2,4-triazole derivative 3-(pyrazinyl)-1,2,4-triazole (Hpztrz) is isolated and structurally characterized. X-ray structural analysis shows that Hpztrz ligands and acetate anions demonstrate different coordination modes in complex 1. The two Cu(II) ions are bridged by the 1,2,4-triazole ring of Hpztrz to form a dinuclear unit, which is further linked by two bridging acetate anions to form a tetranuclear Cu4 unit. Interestingly, each Cu4 unit is connected to another four Cu4 units through the outer pyrazinyl of Hpztrz, resulting in a two-dimensional (2D) layer structure. Consecutive layers are further packed into three-dimensional (3D) structures through interlayer hydrogen-bonding interactions. Furthermore, variable-temperature magnetic susceptibility studies reveal that the antiferromagnetic interactions are mediated through 1,2,4-triazole-N1,N2 bridges and acetate bridges with coupling constants of J1 = − 69.98 cm−1 and J2 = − 2.15 cm−1. Synergistic co-coordination of 1,2,4-triazole and acetate ions with Cu(II) ions led to a dinuclear unit, then to a Cu4 unit and finally to a 2D layer. Consecutive layers are further packed into a 3D framework through interlayer hydrogen-bonding interactions. Furthermore, variable-temperature magnetic susceptibility studies indicated the existence of antiferromagnetic coupling between the Cu(II) ions.

Hirshfeld Surface Analysis and Fingerprint Plots in Determining the Resemblance of a New Copper Coordination Polymer Synthesized by Two Different Methods

The syntheses and crystal structure of a new copper-based coordination polymer {[Cu(2,2′-bipy)(H2O)××(3,4-pydc)]·2.5H2O}n, is here described for the first time. This compound is obtained through two different synthetic methods: hydrothermal and conventional. According to the literature, different methods may result in different products. After X-ray diffraction measurements, it is observed that the same crystal structure was obtained. However, sometimes, even if the asymmetric unit is the same, the packing arrangement may be different, characterizing polymorphs. In order to define whether these two structures represent the same compound, the Hirshfeld surface analysis and fingerprint plots are used since they compare not only the asymmetric structure itself, but the intermolecular interactions as well. After these analyses it is stated that different synthetic methods give the same structure for the describet coordination polymer.

Hirshfeld surface analysis and fingerprint plots in determining the resemblance of a new copper coordination polymer synthesized by two different methods

The syntheses and crystal structure of a new copper-based coordination polymer {[Cu(2,2'-bipy)(H2O)(3,4-pydc)]·2.5H2O}n, is here described for the first time. This compound is obtained through two different synthetic methods: hydrothermal and conventional. According to the literature, different methods may result in different products. After X-ray diffraction measu­rements, it is observed that the same crystal structure was obtained. However, sometimes, even if the asymmetric unit is the same, the packing arrangement may be different, characterizing polymorphs. In order to define whether these two structures represent the same compound, the Hirshfeld surface analysis and fingerprint plots are used since they compare not only the asymmetric structure itself, but the intermolecular interactions as well. After these analyses it is stated that different synthetic methods give the same structure for the herein described coordination polymer.

One-, two- and three-dimensional coordination polymers based on copper paddle-wheel SBUs as selective catalysts for benzyl alcohol oxidation

Copper-based coordination polymers, Cu2(μ2-MeCO2)4(DABCO) (1), [Cu(1,4-BDC-Br)(DABCO)0.5]. xDMF.yH2O (2) and Cu(1,4-BDC-OH)(DMF) (3) (1,4-BDC-Br = 2-bromoterephthalate, DABCO = triethylenediamine, 1,4-BDC-OH = 2-hydroxyterephthalate) were solvothermally synthesized. Two polymorphs of 1 (1a and 1b) were obtained which both contain 1-D chains with similar connectivity and different packing. Compound 2 is a 3-D metal-organic framework (MOF) and 3 exhibits a 2-D structure. Structural analyses of the coordination polymers showed that they all have similar paddle-wheel secondary building units (SBUs). The coordination polymers 1–3 were characterized by FT-IR, thermogravimetric analysis (TGA), powder X-ray diffraction (XRD) and atomic absorption spectroscopy. Compound 2 is further analyzed by nitrogen adsorption/desorption technique. The obtained coordination compounds were employed as heterogeneous catalysts for selective oxidation of benzyl alcohol to benzoic acid using CH2Cl2 as solvent and tert-butyl hydroperoxide (TBHP) as oxidant. The catalysts displayed good activity in the oxidation reaction and could be reused without noticeable loss of activity.

Tunable nanochannels enable selective gas adsorption

Typical gas separation nanomaterials such as zeolites and microporous carbon have rigid pores, making it difficult to control gas diffusion within the material. Now, researchers led by Kyoto University’s Susumu Kitagawa have designed a nanoporous soft crystal that can selectively adsorb and store various gas molecules (Science 2019, DOI: 10.1126/science.aar6833). The material consists of a copper-based porous coordination polymer with metal centers linked by butterfly-shaped ligands made from isophthalic acid and phenothiazine 5,5-dioxide (OPTz). This structure forms an array of nanocages connected by diffusion channels. At low temperatures, the entrances to the nanocages are so small that gas molecules can’t fit through. But with increased temperature, the wing tips of the OPTz units flip up, enlarging the nanocage entrances and allowing the gas molecules to move from one nanocage to another. By varying the temperature, researchers can control the size of the cage entrances so that they selectively adsor...

From 1D copper-based metal-organic coordination polymer to 1D multi-walled carbon nanotube: fabrication, characterization and property

A Cu(II) metal-organic coordination polymer (MOCP) based on the a bis-pyridyl-bis-amide N,N′-bis(3-pyridinecarboxamide)-1,2-cyclohexane (3-bpah) ligand, namely, [Cu(3-bpah)(3-nph)(H2O)] (1) (3-H2nph = 3-nitrophthalic acid), has been synthesized under hydrothermal conditions, which was transformed from 1 D copper-based MOCP to 1 D multi-walled carbon nanotube (MWCNT). Furthermore, the structures of MOCP and MWCNT, electrochemical behaviors and dye adsorption properties of the copper-based MOCP and MWCNT have been also studied and discussed.

Copper based coordination polymers based on metalloligands: utilization as heterogeneous oxidation catalysts.

This work presents the synthesis and characterization of two Cu(ii)-based coordination polymers prepared by utilizing two different Co(iii)-based metalloligands offering appended arylcarboxylic acid groups. Both coordination polymers are three-dimensional in nature and present pores and channels filled with water molecules. Both coordination polymers function as heterogeneous catalysts for the epoxidation of various olefins using O2 while employing isobutyraldehyde as the coreductor and for peroxide-mediated oxidation of assorted benzyl alcohols. The catalytic results illustrate efficient oxidation reactions, whereas the hot-fltration test and leaching experiments indicate the true heterogeneous nature of the catalysis.