Copper Metal Ions Research Articles

The Sulfur Rich Fluorothiophosphate Dianions [S5 P2 F2 ]2- and [S3 PF]2- : Cluster and Chelation Control of P-S Heterolysis.

The sulfur rich difluoropentathiodiphosphate dianion [S5 P2 F2 ]2- , from fluoride addition to P4 S10 , has a somewhat checkered history and proves to be the main product of the reaction in acetonitrile. Its optimized synthesis, and structural characterization, as either a tetraphenylphosphonium or a tetrapropylammonium salt, [Nn Pr4 ]2 [S5 P2 F2 ] allows for the first coordination chemistry for this dianion. Reactions of [S5 P2 F2 ]2- with d10 metal ions of zinc(II), and cadmium(II), and d9 copper(II) resulted in a surprising diverse array of binding modes and structural motifs. In addition to the simple bis-chelate coordination of [S5 P2 F2 ]2- with zinc, cleavage of the P-S bond resulted in complexes with the unusual [S3 PF]2- fluorotrithiophosphate dianion. This was observed in two cluster complexes: a trinuclear cadmium complex with mixed [S5 P2 F2 ]2- /[S3 PF]2- ligands, [Cd3 (S5 P2 F2 )3 (S3 PF)2 ]4- as well as an octanuclear copper cluster, [Cu8 (S3 PF)6 ]4- which form rapidly at room temperature. These new metal/sulfur/ligand clusters are of relevance to understanding multimetal binding to metallothionines, and to potential capping strategies for the condensed nanoparticulate cadmium chalcogenide semiconductors CdS and CdSe.

Lead and copper metal ion uptake by a novel nanoscale hydroxy-terminated dendritic macromolecules

A rapidly growing global population has prompted a pressing concern about how to maintain a safe environment for future generations as a result of massive growth in agricultural, industrial, and economic activities. Environment harmful metals are found in industrial wastewater, which can harm living organisms. Because of heavy metals' strong recalcitrance and long-term existence in the environment, it's crucial to create novel materials for their adsorption. A dendrimer is a good way to adsorb heavy metals. The current work's purpose is to design dendritic macromolecules up to generation three using 1,3-bis(4,6-Dichloro-1,3,5-triazine-2-yl)thiourea as a structural core. Dendrimer structure was characterized by FT-IR and 1H NMR measurements. The adsorption properties of synthesized dendrimer were investigated using different pH, contact duration and generation number for the removal of Pb+2 and Cu+2 metal ions from aqueous systems. Dendrimer-metal complexes were analysed using FT-IR methods to confirm their metal content. In this Research study, divergent growth of dendrimers was successfully used to synthesize different generations of hydrophilic triazine-based dendritic macromolecules. We aimed to investigate the capability of synthesized dendrimer as an adsorbent to remove Pb+2 and Cu+2 metal ion in aqueous systems. According to the study data, products synthesized with higher generations of dendrimers have greater adsorption capability than products synthesized with lower generations of dendrimers.

A Low-Cost Resilient Chalcogenide Ion-Sensitive Electrode for Copper Sensing With an LoD $< $20 ppb

A solid-state ion-sensitive electrode for the monitoring of copper metal ions in water based on a CdS chalcogenide thin film is fabricated using a low-temperature process. This sensor exhibits a limit of detection of 18.7 ppb. A sensing layer consisting of a chalcogenide material was deposited over a conducting substrate using a low-temperature chemical bath deposition process. Electrochemical impedance spectroscopy and potentiometric measurements were carried out to analyze the response of the sensing layer to the copper ions in water samples. The sensor yields a monotonic response in the concentration range of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${1\times 10^{-3}}$</tex-math></inline-formula> to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${1\times 10^{-7}}\ \mathrm{M}$</tex-math></inline-formula> with a response time of a few seconds. The resulting sensor is compatible with large-area fabrication techniques on flexible substrates.

Construction of a novel double network polymer composite and evaluation of its highly efficient adsorption properties for copper ions

AbstractTo explore more efficient heavy metal copper ions adsorbents with double network polymers, this work has presented the novel fabrication processes of the polymer composite diatomaceous earth/polydopamine‐polyethyleneimine/alginate DE@PDA‐PEI@SA, which was characterized by FT‐IR, SEM, EDS, XPS, and was efficiently utilized for copper ions adsorption. The relevant adsorption behaviors of DE@PDA‐PEI@SA for copper ions such as the effect of pH, the effect of adsorbent dosage, adsorption kinetics, adsorption isotherm etc. have been investigated. The results reveal that the adsorption kinetics of DE@PDA‐PEI@SA for copper ions at different temperatures can be modeled by the pseudo second‐order rate equation, the experimental data fit well with the Langmuir isotherm model, indicating a homogeneous monolayer adsorption, and the maximum adsorption capacity of DE@PDA‐PEI@SA for copper ions could reach 454.55 mg/g at 35°C that is very high compared to other reported adsorbent materials. The research results indicate that DE@PDA‐PEI@SA is a novel efficient adsorbent with high efficiency in wastewater treatment and water purification, which could provide a facile processing for copper adsorption.

Design and synthesis of novel heterocyclic pivalamide ligands and their copper(II) complexes: Structure, BSA/DNA interactions and SOD synzyme activity

Four new heterocyclic pivalamide based ligands (L1-L4) and their respective mononuclear copper(II) complexes (C1 = [Cu(N-(thiazol-2-yl)pivalamide)2], C2 = [Cu(N-(5-methylthiazol-2-yl)pivalamide)2], C3 = [Cu(N-(benzothiazol-2-yl)pivalamide)2], C4 = [Cu(N-(benzoimidazol-2-yl)pivalamide)2]) were synthesized to serve as low molecular weight SOD mimics. The complexes were characterized by single crystal XRD, Hirshfeld surface analysis, FT-IR, UV–vis, EPR and ESI-MS studies. C1 crystallizes out in a triclinic system with P-1 space group, while C2 and C4 belong to P21/c and P21/n space groups respectively, from monoclinic system. The crystal structures indicate nearly square planar geometry where mononuclear copper(II) metal ions have coordinated with O and N donor atoms of the pivalamide ligands in trans fashion. All the complexes can scavenge superoxide concentration at low concentrations, in the order C2 < C3 < C1 < C4. The interaction of all the complexes with BSA (bovine serum albumin) protein investigated using fluorescence titration method indicated a static quenching mechanism (KBSA values of the order 105 M−1). The ability of the complexes to bind with calf thymus DNA were also evaluated using absorption and fluorescence titration methods and an intercalative interaction mode of the complexes with DNA was established (Kb values of the order 104 M−1). The complexes have a strong ability to cleave supercoiled plasmid DNA.

Self-assembly of 2D coordination complex of cytidine monophosphate to boost up the optical phenomena

The cytosine 5ʹ-monophosphate (CMP) is significantly distributed in nature due to the existence of deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) as a nucleotide. It is doped with the copper (II) metal ion in the presence of 4,4-bipyridine (4,4ʹ-BIPY) to develop 2D-Nucleotied metal-organic frame (NMOF) work. Cytosine 5ʹ-monophosphate has significant potential in the Pharmacophore due to its promising application in medicine but did not study for NLO properties yet. Keeping in view, the present quantum chemical investigation for the first time, shed light on the promising structure, charge transport, and comparative study of nonlinear properties (NLO) of complex-1 (Di [(2R,3S,4R,5R)-5-(4-Amino-2-oxopyrimidin-1(2H)-yl)-3,4-dihydroxyoxolan-2-yl] methyl dihydrogen phosphate-di-4-pyridin-4-ylpyridine-di-aqua copper (0) nonaaqua) and its ligands [CMP]2− and BPE. Density functional theory (DFT) is used to find structural parameters and NLO properties at the LANL2DZ/B3LYP and LANL2DZ/CAM-B3LYP level of theory. At the same time, Harish field analysis gives information about donor and acceptor within the coordination complex-1 and self-assembly of 2D-layer, respectively. NLO behavior of designated complex-1 showed excellent response compared to [CMP]2− and BPE that was revealed via NBO analysis, the density of states (DOS), HOMO–LUMO gap, molecular electrostatic potential, hyperpolarizability, transition dipole moment density, frontier molecular orbital. Moreover, the result showed that the first, second, and third-order hyperpolarizability was tremendously obtained. This experimental Work gives researchers and genetic engineers a direction to understand electronic behavior. It gives us the right choice about 2D complex-1, which considerably impacts the nonlinear optical property.

The X-ray crystal structures, molecular docking and biological activities of two novel Cu(II) and Zn(II) complexes with a ligand having a potentially N4O2 donor set and two nitro phenyl rings as pendant arms

A new ligand (L) containing two nitro phenyl rings as side chains was synthesized. The reaction of this ligand with copper(II) and zinc(II) metal ions gave complexes with different coordination environments. The free ligand and the metal complexes were characterized using a number of spectroscopic methods. The crystal structure of [ZnLBr]ClO4 showed that the Zn(II) ion was in a distorted square pyramidal environment. The crystal structure of [CuL](ClO4)2 showed that the Cu(II) ion is in a tetragonally distorted octahedral environment. Molecular docking studies with DNA indicated that the binding of L, [ZnLBr]ClO4 and [CuL](ClO4)2 involved the major groove of DNA, H-bonds and Vander Waals interactions. In contrast, the molecular docking of L, [ZnLBr]ClO4 and [CuL](ClO4)2 with human glutathione reductase (GR) showed that the dominant interactions of these compounds with GR were H-bonding, vander Waals and hydrophobic interactions. The antioxidant activity of the synthesized complexes was analyzed by the free radical scavenging activity using 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay with [CuL](ClO4)2 showing maximum activity. In addition, in vitro anticancer activity of the complexes against human breast MCF-7 cancer cell line was confirmed through 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium (MTT) assay. All compounds showed a dose-dependent inhibitory effect on the growth of breast cancer cells with the inhibition activity of [CuL](ClO4)2 being more active than the other synthesized compounds. Furthermore, results from the antibacterial activity screening of the compounds against two Gram-positive and Gram-negative pathogenic bacteria by the micro-broth dilution and disk diffusion methods indicated that [CuL](ClO4)2 complex had the strongest antibacterial potential.

Wastewater treatment using coconut fibre ash as an adsorbent for removal of heavy metals

The study aimed at evaluating the performance of coconut fibre ash as an alternative low-cost adsorbent to the synthetic adsorbents used in wastewater treatment. This research aims to identify the optimum condition for the adsorption process, considering the effect of particle size, adsorbent dosage, and contact time of adsorbents of coconut fibre ash in removing lead (Pb), copper (Cu), and zinc (Zn) metal ions from electroplating wastewater. The adsorbents coconut fibre ash was prepared through activation of carbon at 450º C after following proper cleaning and drying process. The experiments were conducted at varying adsorbent dosages (0.2 g, 0.6 g, and 1 g), particle size (50 to 200 microns), and contact times (40 minutes, 80 minutes, and 120 minutes). The result shows that adsorbents show less efficiency in removing Zn metal ions, which is not more than 34% in the case of 1g adsorbent dosage, particle size ranges 100-200 microns, and 120 minute contact time. The maximum removal efficiency of 95.04% and 80% was obtained at the optimum amount (1g) of adsorbent dosage for Pb and Cu respectively. In the case of contact time, it was identified that the optimum condition for maximum removal efficiency is 120 minutes with a 1g adsorbent dosage both for Pb and Cu ions. To ensure maximum removal of metal avoiding any desorption of the metal ion from the adsorbent surface, it was identified that a maximum contact time of 120 minutes should be allowed for adsorption. However, it could be concluded that adsorbents of coconut fibre ash can be used in treating wastewater facilitating good adsorption capacity in removing heavy metals, low cost and availability.

Cytosine as a root to a nonconventional layered hydroxide nanostructure

A self-assembled layered compound of formula {[Cu5(OH)8Cyt2]·2ClO4} n (1) was obtained from the direct reaction between copper perchlorate and cytosine. Thanks to its peculiar structural features, this coordination compound can be classified as an intermediate nonconventional analog of Layered Simple Hydroxides (LSHs) and Layered Double Hydroxides (LDHs), two fascinating classes of inorganic materials with variable chemical composition and structures. Like LDHs, 1 consists of positively charged layers of metal hydroxides and non-framework charge-balancing anions located between the layers. However, the hydroxide layers, similar to LSHs, contain only divalent copper(II) metal ions, supported by cytosine molecules with long contacts. Cytosine coordinates to the metal centers adopting an unusual µ3 coordination mode, the exocyclic oxygen atom simultaneously binding to three adjacent copper(II) centers. This coordination mode has not been observed with transition metal ions. This work further demonstrates that nucleobases and their derivatives, despite presenting a limited pool of molecules, can potentially afford a significantly expanded set of compounds with diverse nanostructures, owing to their multiple metal binding sites of different coordination properties and their ability to direct assembly of highly ordered structures. Their potential as building blocks should be further explored for the preparation of new bio-inorganic hybrid materials.

Selective Removal of Iron, Lead, and Copper Metal Ions from Industrial Wastewater by a Novel Cross-Linked Carbazole-Piperazine Copolymer.

A novel cross-linked Copolymer (MXM) was synthesized by the polycondensation reaction of 3,6-Diaminocarbazole and piperazine with p-formaldehyde as a cross-linker. The Copolymer was fully characterized by solid 13C-NMR and FT-IR. The thermal stability of MXM was investigated by TGA and showed that the Copolymer was stable up to 300 °C. The synthesized polyamine was tested for the removal of iron (Fe2+), lead (Pb2+), and copper (Cu2+) ions from aqueous and industrial wastewater solutions. The effect of pH, concentration and time on the adsorption of iron (Fe2+), lead (Pb2+), and copper (Cu2+) ions was investigated. The adsorption of the studied ions from aqueous solutions onto the MXM polymer occurs following the Freundlich isotherm and pseudo-second-order kinetic models. The intraparticle diffusion model showed that the adsorption mechanism is controlled by film diffusion. The regeneration of MXM showed practical reusability with a loss in capacity of 2–5% in the case of Fe2+ and Cu2+ ions. The molecular simulation investigations revealed similarities between experimental and theoretical calculations. Industrial wastewater treatment revealed the excellent capabilities and design of MXM to be a potential adsorbent for the removal of heavy metal ions.

Modified low cost engineered biochar prepared from neem de-oiled cake for heavy metal sorption

In this work, the sorption of nickel, chromium, and copper metal ions from an aqueous solution was tested using low-cost engineered neem de-oiled cake biochar (ENDCB). The characterization of ENDCB was performed by BET and SEM techniques. The potential parameters effects such as adsorbent dosage (1–5 g/L), temperature (25–60 °C), contact time (15–120 min), and metal ion concentration (25–150 mg/L) of copper, chromium, and nickel were performed on the batch mode. The greater removal percentageof copper, nickel, and chromium was noticed at a contact time of 60 min, initial concentration of 100 mg/L, the adsorbent dosage of 5 g/l, and temperature of 30 °C as 93.3%, 85.4%, and 96.6% respectively. Among various regenerating agents, maximum desorption percentage (92.3% copper, 84.23% nickel, and 95.5% chromium) was noticed at 0.8 M H2SO4.The ENDCB showed stability up to 3 cycles.

Tuning of Carbon Microspheres and Graphene Structures with Hetero Atoms for Organic Dye Degradation and Heavy Metal Remediation - Influence of Fructose as a Precursor

In today’s context, there is a tremendous potential for the design of smart nanomaterials of carbon origin for multi-dimensional applications. The role-play of precursor is significant in the design of nanometric carbon materials apart from other experimental parameters. Correlation of the synthetic methodology, the microstructure of the product helps to tune and widen the applications aspect. The present study aimed to tune the simple ketose (reducing monosaccharide) of fructose to functionalize (with O, N, and S atoms) carbon layers, microspheres of carbon, to optimize the experimental conditions, and to establish the mechanism involved in the process. The study further explored the catalytic ability of the carbon samples in the degradation of thiazine and xanthene-based textile dyes and the sensing of heavy metal ions of chromium and copper. A simple hydrothermal process, fructose as a precursor, alkaline pH, and appropriate calcination temperature provided micro and nanostructures of carbon viz. carbon microspheres (CMs), graphene oxide (GO), sulfur doped graphene oxide (S-GO), and nitrogen-doped reduced graphene oxide (N-rGO). In this study a simple mechanism for the conversion process is suggested. Further, the results of the preliminary screening study on the catalytic ability of the sulfur and nitrogen-doped graphene samples in the presence of UV and Visible light upon the degradation of methylene blue (MB), methyl orange (MO), Rhodamine-B (Rh-B) dyes were satisfactory. The adsorbent and the ion exchange capacity of the carbon microspheres were found to be excellent. The results of the study will contribute positively to the treatment and management of industrial wastewater.

Synthesis of bimetallic Metal-Organic Frameworks composite for the removal of Copper(II), Chromium(VI), and Uranium(VI) from the aqueous solution using fixed-bed column adsorption

NiCo(BDC) bimetallic Metal-Organic Framework (MOF) is impregnated with MnO2 particles to synthesize a highly stable NiCo(BDC)@MnO2 composite. This MOF composite is applied for the removal of Copper (II), Chromium (VI), and Uranium (VI) heavy metal ions from aqueous solutions using batch adsorption and the fixed-bed column method. The physicochemical properties of the composite were analyzed by Fourier transform infrared spectrometry (FTIR), powder X-ray Diffraction (PXRD), Scanning Electron Microscope (SEM), and Brunauer−Emmett−Teller (BET) analysis. TG-DTA analysis shown the composite MOF is thermally stable up to 450°C. X-ray Photoelectron Spectroscopy (XPS) analysis confirms the presence of Nickel, Cobalt, and Mn. The fixed-bed column adsorption experiments on Cu(II), Cr(VI), and U(VI) were conducted to understand the effect of bed height, flow rate, and initial concentration on adsorption efficiency. NiCo(BDC)@MnO2 MOF composite showed a high adsorption capacity of 756.82 ​mg/g for Cu(II), 111.22 ​mg/g for Cr(VI), and 365.25 ​mg/g for U(VI) were examined by the Langmuir isotherm model. The equilibrium studies specified that Cu(II), Cr(VI), and U(VI) adsorption follows pseudo-second-order kinetics in the batch adsorption process and Thomas, Yoon-Nelson, Adam, and Bohart model in fixed-bed column adsorption, which indicates that chemisorption and surface complexation are maybe the primary mechanisms.

Tyrosinase inhibitory effects of the peptides from fish scale with the metal copper ions chelating ability

Tyrosinase inhibitors have important applications in the cosmetics, medical and food industries due to they can effectively inhibit the synthesis of melanin. In this study, tilapia scale polypeptides were used as raw materials, and high-purity polypeptides with metal copper ions chelating ability were obtained by enzymatic hydrolysis, column chromatography, and EDTA elution. In vitro cell model analysis showed that the fish squamous peptides could strongly inhibit the activity of tyrosinase. When the sample concentration was 5 mg·mL−1, its inhibition rate of tyrosinase reached to 59.73%, which had a better inhibition of enzyme activity compared with the positive control of the same concentration. The comprehensive results showed that the fish scale polypeptide with metal copper ions chelating ability could be a strong tyrosinase inhibitor, and might be used to prevent food browning in food-related fields, and could also be used for skin whitening in the fields of medicine and cosmetics.

Multicomponent interpenetrating metal based Alginate-Carrageenan biopolymer hydrogel beads substantiated by graphene oxide for efficient removal of methylene blue from waste water

Sodium alginate beads are usually prepared in the presence of Ca2+ ions. Here we prepared Graphene oxide based Sodium Alginate-Carrageenan (Ala-Car) hydrogel beads using copper metal ions as ionic crosslinker. The hydrogel beads were prepared by injecting bio-polymers into a beaker containing Cu2+ ions following rapid magnetic bead strategy. The shape and mechanical properties of hydrogel beads were influenced by concentration of copper ions and amount of the biopolymers used. Rheological and textural analysis was carried to investigate the mechanical and deformation studies of the hydrogel beads and the concentration of copper ions was optimized accordingly. Structural and morphological characterization was done by using FTIR and FESEM analysis. The hydrogels showed high removal capacity than the reported hydrogels of sodium alginate for methylene blue (MB) removal. Keeping the dosage of the adsorbent concentration constant (Ala:Car:GO = 2:2:1) and pH 9.2 conditions, percent removal ranged between 70% and 80% at lower concentrations and went upto about 90% at 60 mg/L of the initial dye concentration. As per Langmuir model, maximum adsorption was observed to be 132 mg/g for Ala: Car: GO ratio of 2:2:1. The dye absorption followed langmuir adsorption isotherm. The synthesized hydrogel beads show multi-functionalities (double network of polymers and graphene oxide) as such may potentially be used for removal of harmful dyes from the waste water as well as from aqueous waters.

Schiff Base Modified Paper Test Strips for Naked Eye Detection of Copper Ions in Mixed Aqueous Media

A multi responsive Schiff base sensor L with thiophenol moiety was synthesized by the single-step condensation method. The structural analysis of the sensor was proposed by ¹H-NMR, UV- Visible absorption, HRMS and FT-IR spectroscopy. Sensor L exhibited an instant appearance of yellow color on the addition of copper ions. Since copper gave an intense color change, therefore detailed studies were performed for copper sensing w.r.t. designed sensor L. Selectivity and sensitivity of sensor concerning copper metal ions were established by performing various UV-Visible spectroscopic and colorimetric studies. The 1:1 binding framework of the L-Cu^2&#x002B; complex is confirmed by Job&#x2019;s Plot and further supported by DFT studies. With the help of Benesi-Hildebrand equation, the detection limit and the association constants were found to be <inline-formula> <tex-math notation="LaTeX">$3.15 \times 10^{-6}$ </tex-math></inline-formula> M and <inline-formula> <tex-math notation="LaTeX">$1.16 \times 10^{4}$ </tex-math></inline-formula> M^&#x2212;1, respectively. In addition, sensor L was transferred onto solid substrates including silica and paper strips for establishing its utility in the onsite detection of copper ions.

Recent Development in Fluorescent Probes for Copper Ion Detection.

Copper is the third most common heavy metal and an indispensable component of life. Variations of body copper levels, both structural and cellular, are related to a number of disorders; consequently, the pathophysiological importance of copper ions demands the development of sensitivity and selection for detecting these organisms in biological systems. In recent years, the area of fluorescent sensors for detecting copper metal ions has seen revolutionary advances. Consequently, closely related fields have raised awareness of several diseases linked to copper fluctuations. Further developments in this field of analysis could pave the way for new and innovative treatments to combat these diseases. This review reports on recent progress in the advancement of three fields of fluorescent probes; chemodosimeters, near IR fluorescent probes, and ratiometric fluorescent probes. Methods used to develop these fluorescent probes and the mechanisms that govern their reaction to specific analytes and their applications in studying biological systems, are also given.

Synthesis and comparison of two different morphologies of graphitic carbon nitride as adsorbent for preconcentration of heavy metal ions by effervescent salt-assisted dispersive micro solid phase extraction method

The g-C3N4 (GCN) adsorbent with two different morphologies, coral (CGCN) and nano fiber (GCNNF), was synthesized and recruited for extraction and preconcentration of lead and copper metal ions by effervescent salt-assisted dispersive micro solid phase extraction procedure. The structures of the two adsorbents were affirmed by Fourier-transform infrared spectroscopy, X-ray diffraction, field emission scanning electron microscopy and Brunauer–Emmett–Teller analyses. The factors affecting the extraction efficiency were carefully studied and the optimum values of the parameters for both adsorbents were pH 6.5, adsorbent dosage 8 mg, desorption time 3 min, and the elution solvent 300 μL of 2 mol L−1 of HNO3. The detection limits of Pb(II (and Cu(II) ions for CGCN were 0.9 and 0.3 μgL−1 and for GCNNF were 1.56 and 0.7 μgL−1, respectively. The percent relative standard deviations were obtained to be 1.32% and 2.23% for CGCN (n = 3) and 1.24% and 2.29% for GCNNF (n = 3), respectively for the lead and copper metal ions. In addition, the adsorbents could be used up to 7 times without an imperative reduction in the percentages of analytes recovery. Finally, the performance of CGCN and GCNNF were used for preconcentrate of lead and copper ions in honey, canned fish, and human hair samples.

Chirality-Dependent Copper-Diphenylalanine Assemblies with Tough Layered Structure and Enhanced Catalytic Performance.

Chiral regulation to prepare functional materials has aroused considerable interest in recent years. However, little is known on the effect of chirality of ligands in the metal-organic coordination assembly process. We report the self-assembly of diphenylalanine peptide (Phe-Phe, FF), the core fragment of Aβ protein, with metal copper ion (Cu2+) into metal-organic assemblies with chirality-encoded structures and properties. The chirality-dependent metal-dipeptide assembles with different morphologies and supramolecular chirality were obtained by facile changing of the FF chirality. Single-crystal results indicate that (L)-FF coordinated with Cu2+ into a cross-chain structure with a five-coordinated style, while the racemates of (L+D)-FF with Cu2+ crystallized into an (L)-Cu2+-(D)-Cu2+ alternated four-coordinating structure, enabling a higher mechanical and catalytic performance. The Young's modulus of (L+D)-FF-Cu is as high as 34.36 GPa, which is 2.45 times higher than that of (L)-FF-Cu. Furthermore, both of them follow the characteristic enzyme kinetics and show higher catalytic activity than natural laccase at the same mass concentration. Specifically, the calculated catalytic efficiency (kcat/KM) of (L+D)-FF-Cu is 1.14 times higher than that of (L)-FF-Cu, and the (L+D)-FF-Cu shows significantly enhanced stability and reusability compared with (L)-FF-Cu. The results reveal that highly functional materials could be constructed by encoding the chirality of molecular building blocks.

Peculiarities of the Edaphic Cyanobacterium Nostoc linckia Culture Response and Heavy Metal Accumulation from Copper-Containing Multimetal Systems.

Soil and water pollution is a major problem that has a negative impact on ecosystems and human health in particular. In the bioremediation processes, the application of photosynthetic microorganisms, including cyanobacteria, is a direction of action addressed with increasing frequency in the context of further development and improvement of environmentally friendly techniques needed for detoxification of soils and waters polluted with low concentrations of toxic elements, since they pose a challenge for traditional treatment methods. In the present study, the removal of copper and other metal ions from multielement systems by three generations of Nostoc linckia is discussed. Changes in the biochemical composition of the nostoc biomass, which accumulates metal ions, were monitored. Neutron activation analysis was applied to assess Cu, Fe, Ni, and Zn accumulation by biomass, as well as to determine the biochemical composition of biomass after specific biochemical methods were used. The capacity of the accumulation of copper and other metal ions from multi-elemental systems by cyanobacteria Nostoc linckia was high and increased over two cycles of biomass growth in the systems Cu-Fe-Ni and Cu-Fe-Zn and over three cycles in Cu-Fe and Cu-Fe-Ni-Zn systems. It constituted 1720–10,600 µg metal/g depending on the system and cycle of cultivation. The accumulation of Fe, Ni, and Zn also increased over the generations of nostoc. The process of metal accumulation was demonstrated by a significant change in the biomass biochemical composition. Cyanobacteria Nostoc linckia possess a pronounced capacity of copper and other metal ion accumulation from multimetal systems and showed an increased resistance in environments polluted with heavy metals.