Self-assembly Of Cu Research Articles

Utilizing Nanozymatic Activity of Copper-Functionlized Mesoporous C3N5 for Sensing of Biomolecules.

Designing unique nanomaterials for the selective sensing of biomolecules is of significant interest in the field of nanobiotechnology. In this work, we demonstrated the synthesis of ordered and Cu nanoparticles functionalized mesoporous C3N5 with unique peroxidase like nanozymatic activity for the ultrasensitive and selective detection of glucose and glutathione. A nano hard-templating technique together with the in-situ polymerization and self-assembly of Cu and high N-containing CN precursor was adopted to introduce mesoporosity as well as high N and Cu content in mesoporous C3N5. Due to the ordered structure and highly dispersed Cu in the mesoporous C3N5, a large enhancement of the peroxidase mimetic activity in the oxidation of a redox dye in the presence of hydrogen peroxide could be obtained. Additionally, the optimized Cu functionalized mesoporous C3N5 exhibited excellent sensitivity to glutathione with a low detection limit of 2.0 ppm. The strong peroxidase activity of the Cu functionalized mesoporous C3N5 was also effectively used for the sensing of glucose with the detection limit of 0.4 mM through glucose oxidation with glucose oxidase. This unique Cu functionalized mesoporous C3N5 has the potential for detecting various molecules in the environment as well as for next-generation glucose and glutathione diagnostic devices.

Regulated Adaptive Self-Assembly of Cu3I3 Supramolecular Clusters and their Photocatalytic Properties

Regulated Adaptive Self-Assembly of Cu₃I₃ Supramolecular Clusters and their Photocatalytic Properties

Integration of Trinuclear Triangle Copper(II) Secondary Building Units in Octacyanidometallates(IV)-Based Frameworks.

The design and synthesis of high-dimensional materials based on secondary building blocks (SBUs) play a pivotal role in the further development of functional molecular materials. Herein, the self-assembly of Cu(II) ions, pyrazole (Hpz), and octacyanidometallate(IV) anions in the presence of water produced two new isostructural three-dimensional systems {[Cu3(μ3-OH)(μ-pz)3(H2O)3]2[M(CN)8]}·nH2O (M = W, 1, and Mo, 2). 1 and 2 consist of trinuclear triangle copper(II) (TTC) SBUs and octacyanidometallates(IV). At room temperature, both assemblies display strong antiferromagnetic interactions within the TTC entities with an average CuII···CuII isotropic magnetic coupling constant of about -145 cm-1. Moreover, a detailed analysis of magnetic data revealed the presence of spin frustration with antisymmetric magnetic exchange-coupling constants of around +32 and +46 cm-1 for 1 and 2, respectively. Finally, quantum chemical calculations explained their magnetic and optical properties.

Synthesis and characterization of CoFe2O4@TiO2@HKUST-1 as a novel metal-organic framework nanocomposite

A novel metal–organic framework-based nanocomposite has been designed and synthesized via a two-step procedure. First, CoFe2O4@TiO2 nanoparticles have been prepared through initial formation of CoFe2O4 nanoparticles, followed by introduction of TiO2 by using titanium tetraisopropoxide. Subsequently, HKUST-1 metal–organic framework has been formed through self-assembly of Cu(NO3)2·3H2O and trimesic acid in the presence of CoFe2O4@TiO2 nanoparticles. The properties of the resultant nanocomposite, CoFe2O4@TiO2@HKUST-1, have been analyzed via XRD, TGA, TEM, SEM, BET, VSM and FTIR and compared with those of HKUST-1, CoFe2O4@TiO2 and CoFe2O4. It was found that the nanocomposite showed lower specific surface area compared to HKUST-1. Moreover, incorporation of CoFe2O4@TiO2 resulted in significant morphological change. VSM analysis implied that the magnetic properties of CoFe2O4@TiO2 and the nanocomposite were lower than that of CoFe2O4. However, they could be magnetically separated by using an external magnet.

Facile and environmentally friendly one-step synthesis of hexanuclear Cu(II)–Ni(II) and Cu(II)–Co(II) clusters and their binding interactions with bovine serum albumin

The novel hexanuclear {K6[Cu4Co2(μ3-OH)4(μ4-O)(OAc)8][Cu(OAc)4](OH)2}·3H2O (1) and {K6[Cu4Ni2(μ3-OH)4(μ4-O)(OAc)8][Cu(OAc)4](OH)2}·3H2O (2) clusters have been prepared. The clusters were synthesized by the self-assembly of Cu(OAc)2 and M(OAc)2 (M ​= ​Co, Ni) in aqueous solution without any additional other organic ligands. The two clusters were well-characterized with single-crystal X-ray diffraction, FT-IR spectra and elemental analyses. Crystallographic studies revealed that the molecular core type was M6(μ3-OH)4(μ4-O) in both 1 and 2. Solid-state DC magnetization indicated that 2 exhibited strong Ni–O–Ni associated antiferromagnetic interaction, while 1 displayed merely weak antiferromagnetic interaction. The protein binding affinity of two clusters was tested with bovine serum albumin (BSA). Both two clusters showed good affinity with BSA, with a binding constant (Kb) of 4.97 ​× ​104 ​M−1and 2.14 ​× ​104 ​M−1, respectively. Cytotoxic activity was performed by MTT assay. It was observed that the complex exhibited low toxicity against the SH-SY5Y and A549 cancer cells.

2D Metal-Organic Framework Derived CuCo Alloy Nanoparticles Encapsulated by Nitrogen-Doped Carbonaceous Nanoleaves for Efficient Bifunctional Oxygen Electrocatalyst and Zinc-Air Batteries.

The development of efficient bifunctional electrocatalysts for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) still remains a challenge in a wide range of renewable energy technologies. Herein, CuCo alloy nanoparticles encapsulated by nitrogen-doped carbonaceous nanoleaves (CuCo-NC) have been synthesized from a Cu(OH)2 /2D leaf-like zeolitic imidazolate framework (ZIF-L)-pyrolysis approach. Leaf-like Cu(OH)2 is first prepared by the ultrasound-induced self-assembly of Cu(OH)2 nanowires. The efficient encapsulation of Cu(OH)2 in ZIF-L is obtained owing to the morphology fitting between the leaf-like Cu(OH)2 and ZIF-L. CuCo-NC catalysts present superior electrocatalytic activity and stability toward ORR and OER over the commercial Pt/C and IrO2 , respectively, which are further used as bifunctional oxygen electrocatalysts in Zn-air batteries and exhibit impressive performance, with a high peak power density of 303.7 mW cm-2 , large specific capacity of up to 751.4 mAh g-1 at 20 mA cm-2 , and a superior recharge stability.

Self-assembly of Cu(I) metallomacrocycle and coordination polymers with 2,2′:5′,4″-terpyridine directed by anions and solvents

The reaction of [Cu(MeCN)4]X (X = BF4, PF6) with 2,2′:5′,4″-terpyridine (2,2′:5′,4″-terpy) in MeOH/MeCN under Ar/C2H4 afforded 1-D Cu(I) coordination polymers {[Cu(2,2′:5′,4″-terpy)(MeCN)]BF4}n (1) and {{[Cu(2,2′:5′,4″-terpy)(MeCN)]PF6}2·H2O}n (2). In complex 1, the tetrahedral Cu(I) atoms are bridged by 2,2′:5′,4″-terpy in the head-to-tail fashion to form an infinite 1-D zigzag chain structure. In complex 2, there are two independent infinite 1-D zigzag chain structures along the b- and c-axises in the unit cell. The weak intermolecular π⋯π stacking interactions exist between opposite 2,2′:5′,4″-terpy ligands. The PF6– anions are surrounded by four opposite MeCN molecules in two crossed zigzag chains. In contrast, the reaction of [Cu(MeCN)4]PF6 with 2,2′:5′,4″-terpy in Me2CO/MeCN under Ar/C2H4 afforded Cu(I) metallomacrocycle [Cu4(2,2′:5′,4″-terpy)4](PF6)4·5Me2CO (3). Four Cu(I) atoms are bridged by the four 2,2′:5′,4″-terpy in a head-to-tail fashion to afford a rhombic Cu(I) metallomacrocycle. One distorted Me2CO molecule is encapsulated in the central vacant space of [Cu4(2,2′:5′,4″-terpy)4]4+ core and two PF6– anions are sandwiched between the rhombic Cu(I) metallomacrocyclic layers. The reactions of Cu(NO3)2·3H2O and Cu turnings with 2,2′:5′,4″-terpy in MeOH/MeCN under Ar afforded 1-D Cu(I) coordination polymer {[Cu(2,2′:5′,4″-terpy)(MeCN)]NO3}n (4). It has been proved that complex 4 could be induced by the autoreduction of Cu(II) species to Cu(I) species.

Construction of a porous Cu(II)-coordinated framework for the catalytic properties of cycloaddition of carbon dioxide to epoxides

A new porous material {[Cu2(acc)1.5(phen)2]}n (denoted as 1) was synthesized by the self-assembly of Cu(II) ions with two mixed ligands, 4-carboxycinnamic acid (H2acc) and phenanthroline (phen), and further structurally characterized. The single crystal X-ray diffraction indicated that 1 contained a two-dimensional network with bimetallic Cu(II) clusters. The magnetic susceptibility experiments showed the antiferromagnetic interactions between the two Cu(II) cores. Additionally, 1 could serve as an effective heterogeneous catalyst for cyclic carbonates reactions between epoxides and CO2, achieving a high yield of above 99% in a mild condition.

Unprecedented coordination solvate effects of bimetallic copper(II) cages on catechol oxidation catalysis

Self-assembly of Cu(OTf)2 with a new N,N′,N″-((benzene-1,3,5-triyltris(oxy))tris(benzene-2,1-diyl))trinicotinamide ligand (L) in a mixed solution gives rise to single crystal of [Cu2L2(OTf)3(Sol)(H2O)2]OTf (Sol = Me2CO, H2O, MeOH) cages. Their skeletal structure is a bimetallic cage with copper (II) (Cu(II)) sites of corresponding coordinated solvate molecules. These crystals have been employed as hetero-catalysts for 3,5-di-tert-butylcatechol oxidation, showing significant and different catalytic effects in dichloromethane according to the coordinated solvate molecules in the order Sol = Me2CO > MeOH > H2O. Such notable catalytic effects can be explained by the dissociation ability of coordinated solvate molecules at the catalytic center.

Self-Assembly of Cu2O Monolayer Colloidal Particle Film Allows the Fabrication of CuO Sensor with Superselectivity for Hydrogen Sulfide.

CuO monolayer colloidal particle films with controllable thickness and homogeneous microstructure were prepared by self-assembly and subsequent calcination based on Cu2O colloidal particles. Large-scale CuO monolayer colloidal particle films have the particle size of 300-500 nm, and CuO colloidal particles are hollow. It was found that such a structure exhibits excellent room-temperature H2S-gas-sensing properties. It not only has high sensing response and excellent selectivity, but also has a low limit of detection of 100 ppb. The sensors exhibit different sensitive characteristics at low and high concentrations of H2S. At low concentration (100-500 ppb), the sensor can be recovered with the increase of gas response, although it takes a longer recovery time at room temperature. At medium concentration (1-100 ppm), although the gas response still increases, the sensor is irreversible at room temperature. When the concentration continues to increase (>100 ppm), the sensor is irreversible at room temperature, and the gas response first increases and then decreases. Two reaction mechanisms are proposed to explain the above-mentioned sensing behavior. More importantly, quasi in situ X-ray photoelectron spectra confirm the existence of CuS. The CuO sensor with room-temperature response and superselectivity will find potential applications in industry, environment, or intelligent electronics.

Enhanced photothermal behavior derived from controllable self-assembly of Cu1.94S microstructures.

New ordered architectures or morphologies could be obtained through the self-assembly process and usually generate new physical and chemical properties. Here we report an adjustable self-assembly research study on copper sulphide nanocrystals (Cu1.94S NCs) forming five kinds of plant-like morphologies. Hydrophobic Cu1.94S quantum dots were prepared in the CHCl3 phase and transferred to the aqueous phase and capped with cysteine or penicillamine through a ligand exchange technique. Afterwards, a facile and eco-friendly self-assembly process (without using any template or surfactant) was employed. Through regulating the conditions including the solvent composition, surface ligand and starting concentration of Cu1.94S NCs, five delicate architectures were obtained. In addition, the possible formation process and growth mechanism of the obtained three-dimensional (3D) Cu1.94S architectures was also proposed and discussed. The assembled Cu1.94S architectures show improved molar extinction coefficients compared with individual Cu1.94S NCs, and in this way, better photothermal performance is achieved.

Anion‐Directed Metallocages: A Study on the Tendency of Anion Templation

Self-assembly of Cu(NO3 )2 ⋅3 H2 O and di(3-pyridylmethyl)amine (dpma) with addition of different acids (HNO3 , HOAc, HCl, HClO4 , HOTf, HPF6 , HBF4 , and H2 SO4 ) afforded a family of anion-templated tetragonal metallocages with a cationic prismatic structure of [(Gn- )⊂{Cu2 (Hdpma)4 }](8-n)+ (Gn- =NO3- , PF6- , SiF62- ) with different ligating anions/solvents (NO3- , Cl- , ClO4- , OTf- , H2 O) outside the cage. Systematic competitive experiments have rationalized the tendency of anion templation towards the formation of metallocages [(Gn- )⊂{Cu2 (Hdpma)4 }](8-n)+ as occurring in the order SiF62- ≈PF6- >NO3- >SO42- ≈ClO4- ≈BF4- . This sequence is mostly elucidated by shape control over size selectivity and electrostatic attraction between the cationic {Cu2 (Hdpma)4 }8+ host and the anionic guests. In addition, these results have also roughly ranked the anion coordination ability in the order Cl- , ClO4- , OTf- >NO3- >BF4- , CH3 SO4- . Magnetic studies of metallocages 1 t and 2-4 suggest that the fitted magnetic interaction, being weakly magnetically coupled overall, is interpreted as a result of the combination of intracage ferromagnetic coupling integrals and intercage antiferromagnetic exchange; both contributions are very weak and comparable in strength.

Self-assembly of a novel Cu(ii) coordination complex forms metallo-vesicles that are able to transfect mammalian cells

Coordination-directed self-assembly of a Cu(ii) amphiphilic complex forms homogeneous nanometer-sized metallo-vesicles in water with low toxicity and gene transfection properties.

Surface adsorption and self-assembly of Cu(II) ions on TEMPO-oxidized cellulose nanofibers in aqueous media

TEMPO-mediated oxidized cellulose nanofibers (TOCNFs) have shown potential in the bioremediation of metal ions from contaminated water due to their interaction with positively charged metal ions via electrostatic interactions involving surface carboxyl groups. Copper is one of the most common pollutants in industrial effluents and is thus the target metal in the current study. The specific surface adsorption of Cu(II) was similar for TOCNFs with different degrees of functionalization and directly impacted the zeta potential. SEM imaging of the TOCNF after Cu(II) adsorption revealed interesting nanostructured clusters that were attributable to Cu(II) ions first being adsorbed by carboxylate groups on the TOCNF and subsequently being reduced and self-assembled to Cu(0) nanoparticles (NPs) or copper oxide NPs by microprecipitation. TOCNF turned superhydrophilic and resulted in faster water filtration after copper adsorption due to the stronger polarity of the copper ions or the self-assembled Cu(0) NPs creating voids or highly water-permeable channels at the interface between the interconnected TEMPO-oxidized nanofibers. Thus, the adsorption of Cu(II) ions and self-assembly into the Cu NPs on TOCNF favors a faster water purification process and provides a viable route to reuse/recycle TOCNFs studded with Cu nanoparticles as biocidal materials.

Composition-Dependent Crystal Phase, Optical Properties, and Self-Assembly of Cu–Sn–S Colloidal Nanocrystals

We demonstrate a robust protocol for preparing monodisperse copper–tin–sulfide (CTS) nanocrystals (NCs) of tunable composition and controlled crystal phase. We show that the crystal phase of CTS NCs is determined not only by the reactivity of chalcogenide precursors but also by the cation composition (Cu:Sn ratio) and identity of ligands bound to the NC surface. In contrast to previous studies, we demonstrate broad variation of the Cu:Sn ratio in the product NCs, in both directions from the stoichiometric Cu2SnS3 compound. Localized surface plasmon resonance in the CTS NCs was tuned by varying the Cu:Sn elemental ratio. This demonstrates that the doping level of such alloy semiconductor NCs can be manipulated by varying the cation composition. This result opens new possibilities for applying CTS and related materials for solution-processed photovoltaic devices, by taking advantage of controllable and variable doping. In addition, reversible gelation of colloidal CTS NCs in nonpolar solvents was observed a...

Homochiral coordination cages assembled from dinuclear paddlewheel nodes and enantiopure ditopic ligands: syntheses, structures and catalysis.

A series of homochiral metal-organic cages (MOCs) have been obtained from self-assembly of Cu(II) salts with chiral N,N'-(bicyclo[2,2,2]oct-7-ene-tetracarboxylic)-bis-amino acids. Single-crystal X-ray diffraction analyses reveal that these compounds show a lantern-type cage structure, in which one pair of Cu2(CO2)4 paddlewheels is linked by four diacid ligands. The resulting homochiral cages have been fully characterized by EA, TOF-MS, TGA, VTPXRD, IR, UV, and CD measurements. The catalytic tests reveal that these Cu(II) cages are effective in cyclopropanation with excellent diastereoselectivity (up to 99 : 1 E/Z). In addition, the cage catalysts can promote the aziridination reaction with PhI=NNs.

A combined experimental and theoretical study of the supramolecular self-assembly of Cu(II) malonate complex assisted by various weak forces and water dimer

A Cu(II) malonate complex with formula [Cu(C3H2O4)(C6H8N2)(H2O)]2·4H2O (1) [C6H8N2=2-picolylamine, C3H2O42−=malonate dianion] has been synthesized by mixing the reactants in their stoichiometric proportion and its crystal structure has been determined by single-crystal X-ray diffraction. In 1, monomeric neutral metal malonate units [Cu(C3H2O4)(C6H8N2)(H2O)] are interlinked with each other through hydrogen bonds, weak lone pair⋯π and cuprophilic interactions to generate supramolecular dimers, which in turn further associated through hydrogen bonding to form infinite 1D chains. Water dimers, through series of hydrogen bonds and weak π–stacking forces are found to be responsible for interconnection of 1D chains, which resulted in a 3D network. A density functional (DFT) study of the energetic features of several noncovalent interactions observed in the solid state have been analyzed and characterized using Bader׳s theory of “atoms-in-molecules”. We also present here Hirshfeld surface analysis to investigate the close intermolecular contacts.

Effect of non-covalent interaction on the diastereoselective self-assembly of Cu(ii) complexes containing a racemic Schiff base in a chiral self-discriminating process

The effects of π⋯π interactions between benzene–pyridine rings on the diastereoselective self-assembly of Cu(ii) compounds in the chiral self-discrimination process are studied.

Self-assembly of Cu(ii) with amyloid β19–20 peptide: relevant to Alzheimer's disease

Amyloid-β (Aβ) peptide Aβ19–20 tends to self-assemble into well-ordered tubular structures under physiological conditions, while in the presence of equimolar Cu(II), they assembled into homogeneous microvesicles; a chelator can competitively bind to Cu(II) from the Cu(II)–Aβ19–20 complex, resulting in reforming of the peptide tubular structure.

Anion-directed self-assembly of Cu(ii) coordination compounds with tetrazole-1-acetic acid: syntheses in ionic liquids and crystal structures

Reaction of tetrazole-1-acetic acid (1-Htza) with a Cu(II) salt in ionic liquids with different anions, [BMIM]X (BMIM = 1-butyl-3-methylimidazolium; X = Br−, BF4−, NTf2− (NTf2− = bis((trifluoromethyl)sulfonyl)amide)), afforded five Cu(II) coordination compounds, [Cu2(1-tza)4]Br·H3O·1/3H2O (1), [Cu2(1-tza)4]BF4·H3O·H2O (2), [Cu(μ2-Cl)(1-tza)(1-Htza)(H2O)]·0.5H2O (3), [CuCl(μ2-Cl)(1-Htza)2(H2O)]·H2O (4), and [CuCl2(1-Htza)2]·H2O (5). Single-crystal X-ray diffraction analyses reveal that 1–5 display various structures, and the 1-tza− ligand exhibits diverse coordination modes. Compounds 1 and 2 possess higher dimensional structures (a 2-D neutral Kagome topology network for 1 and a 3-D lvt-type topology framework for 2) with fully deprotonated 1-tza− ligands. Compounds 3–5 display lower dimensional structures (1-D, 1-D and 0-D for 3, 4 and 5, respectively) with partly or fully protonated 1-Htza. The anions of ionic liquids have significant influences on the final molecular architectures, which arise from different water miscibility of ionic liquids.