Response Of Cu Research Articles

Preparation of biomass carbon dots/carboxymethyl cellulose-based fluorescent hydrogel: Combines selective detection and visual adsorption for Copper(II)

Abstract In this study, we used nitrogen-doped carbon dots (NCDs), which were synthesized via the hydrothermal method of corn-stover biomass as raw material and polyethyleneimine (PEI) as the nitrogen source, introduced them into the carboxymethyl cellulose-based hydrogel to prepare an environmentally friendly fluorescent cellulose-based hydrogel (NCDs/CMC-PAM). NCDs/CMC-PAM was also used for simultaneous fluorescence monitoring and removal of Cu (II) in aqueous solution. The chemical and physical structures, adsorption behaviors and fluorescent properties of NCDs/CMC-PAM were investigated. The results showed that NCDs/CMC-PAM exhibited a well-linear response range of fluorescence response for Cu (II) (0∼100 μM, detection limit of 3.42 μM). NCDs/CMC-PAM showed maximum adsorption capacities of 237.71 mg/g for Cu (II), the adsorption process followed the Langmuir isotherm model and pseudo-second-order kinetic model, which is an exothermic spontaneous reaction with an increase in entropy. It can still maintain 79.03% of the original adsorption capacity after six cycles (pH=6). The adsorption mechanisms of NCDs/CMC-PAM for Cu (II) are intraparticle diffusion, electrostatic attraction, ion exchange, and ligand interaction. Hence, the present study provides a new green way to synthesize an adsorbent that can be applied for the adsorption and detection of heavy metal ions.

An AIE dynamic a highly selective and expeditious benzothiazole-pyrazine based colorimetric chemosensor for Ni2+and fluorogenic chemosensor for Cu2+ and Al3+ detection

Considerable research focus has been devoted to the advancement of single-component sensors that can identify several analytes. In this regard, a complex chemosensor called BPA was created by building an imine link between benzothiazole and pyrazine. On the flexible imine link, the nitrogen atoms with lone pair electrons were arranged as possible coordination sites to enable changes in molecular configurations and charge transfer. In the aqueous acetonitrile environment, BPA displayed the discriminative identification of Ni2+ by a chromogenic response (color transition from colorless to yellow) and a fluorescence “decreasing” response for Cu2+ via ligand–metal charge transfer. Additionally, BPA exhibited recognition of Al3+ through a “turn-on” fluorogenic response facilitated by the chelation-enhanced fluorescence effect. The detection limits for Ni2+, Al3+, and Cu2+ were remarkably low, measuring 5.19 nM, 16 nM, and 214 nM, respectively. A 1:1 binding stoichiometry and precise complex modes between BPA and the target metal ions were successfully determined using extensive investigations, which encompassed the utilization of Job's plot, mass spectra, NMR, and DFT analysis. The deduced coordination mechanisms were corroborated by computational and experimental methodologies. BPA's potential practical uses were demonstrated by subsequently evaluating its ability to identify Ni2+, Al3+, and Cu2+ in actual water samples and validating its performance on-site using test strips.

Role of geometry and coherent twin boundaries in mechanical response of Cu〈110〉 nanopillars under tensile loading: insights from molecular dynamics simulations

Role of geometry and coherent twin boundaries in mechanical response of Cu〈110〉 nanopillars under tensile loading: insights from molecular dynamics simulations

Molecular imprinting technology for electrochemical sensing of kasugamycin in food products based on Cu2+/Cu+ stripping current.

An electrochemical sensing approach was developed for the detection of the agricultural antibiotic drug kasugamycin. The method involves the construction of an electrochemical sensor comprising molecularly imprinted polymers (MIPs) embedded within a carbon paste (CP) matrix. The MIPs are designed to have imprinted sites that match the size and geometry of the Cu(II)-kasugamycin coordinated complex. Upon removal of kasugamycin, cavities suitable for the drug's entrance are formed within the MIPs. The presence of Cu(II) facilitates the detection of the drug by generating a redox signal of Cu(II)-Cu(I), which can be easily detected using differential pulse voltammetry (DPV). The signal response of Cu(II)-Cu(I) increases in the presence of the drug, promoting the accumulation of Cu(II) ions within the imprinted cavities. Under optimized conditions, the anodic peak (Ipa) signal of Cu(II)-Cu(I) exhibits an increase proportional to the concentration of kasugamycin within the range of 0.15-140 μM. The detection limit (LOD, S/N = 3) achieved is 0.046 μM. The proposed sensor demonstrates several characteristic features including good stability, reliable performance, a low detection limit, and excellent selectivity. The Cu(II)-MIP@CP sensor proved effective in detecting kasugamycin within complex samples like meat, milk, and cucumber, yielding recovery% ranging from 96.0 to 103.8%. Additionally, the relative standard deviation % (RSD%) fell within the range of 2.2% to 4.0%, indicating good precision and reliability.

Influence of Vanadium substitution on electronic, thermoelectric and optical response of Cu2O

Cu2O semiconductor attained much research interest due to excellent electronic and optical response. In this work, Vanadium-doped Cu2O compositions were studied for electronic, thermoelectric, and optical response using density functional theory. The thin films were experimentally fabricated using the chemically derived spin coating method. The x-ray diffraction analysis revealed the growth of crystalline thin films with cubic structure having space-group 224-Pn-3m. The scanning electron micrographs exhibit the uniform grain growth with well-defined grain boundaries for pure Cu2O films. Density of states spectra display the maxima for O-2p and Cu-3d while V-3d states occupied the conduction band. The value of the experimental band gap for pure Cu2O is estimated as 2.02 eV and found to decrease with V-doping. The Seebeck coefficient and specific heat are found to increase with the increment in V-doping content due to thermal fluctuations. A steady increase is observed in real epsilon with the increase in energy and dopant concentration.

Site-specific Cu clustering and precipitation in laser powder-bed fusion 17–4 PH stainless steel

Thermal gyrations inherent to metal additive manufacturing (AM) result in complex microstructural heterogeneities that are linked to the process parameters, geometry, and alloy composition. AM 17–4 precipitation hardened (PH) stainless steel displays heterogeneities due to its multi-phase microstructure where different as-built phases have been reported. These phases include austenite, martensite, and ferrite, as well as varying degrees of AM induced Cu clustering and/or precipitation. To enable a systematic study of the evolution of these strengthening phases, we utilize a non-standard concentric scan strategy to achieve variations in thermal conditions across a build. Using atom probe microscopy and thermal modeling, we show that the response of Cu varies across the build from no clustering at the outer regions to an increased tendency for Cu precipitation towards the center. Our results will enable the tuning of processing parameters to achieve homogenous Cu precipitation, and thus improve mechanical properties of AM 17–4 PH.

Plasmon-Induced Polarity Inversion of Magnetic Circular Dichroism (MCD) Responses of Cu–Fe–S Bornite Nanodots upon Oxidation

Plasmon-Induced Polarity Inversion of Magnetic Circular Dichroism (MCD) Responses of Cu–Fe–S Bornite Nanodots upon Oxidation

Optical and Magnetic Response of Pure and CU-Ions Substituted Dysprosium Oxide Thin Films for Various Applications

Dysprosium oxide (Dy2O3) and Cu/Dy2O3 thin films of thickness 117.14 nm and 258.30 nm, respectively were successfully deposited via a well-known DC-magnetron sputtering technique. Field emission scanning electron microscopy clarifies the growth of uniform and fine granular particles on silicon substrate. The hexagonal closed pack structure for both the thin films has been observed by the x-ray diffraction analysis and it was observed that by inclusion of copper the HCP structure of thin film was retain with a slight shift in the main peak. The reduction from 3.9 eV to 3.8 eV in the energy band gap value was observed by incorporation of copper ions Dy2O3 thin films. The M-H loops obtained through Vibrating Sample Magnetometer (VSM) shows that Dy2O3 thin film behave ferromagnetically at low temperature with a saturation magnetization value of 2860 emu/cc and evolves through its phase transition temperatures and behave paramagnetically at room temperature. In Cu/Dy2O3 case, the diamagnetic response of Cu dominates and produces reverse hysteresis loop at both temperatures make it a suitable candidate for energy and memory storage devices applications.

A multifunctional quinoxaline-based chemosensor for colorimetric detection of Fe3+ and highly selective fluorescence turn-off response of Cu+2 and their practical application

A new dual responsive colorimetric and fluorescent turn-off sensor for Fe3+ and Cu2+ was designed and synthesized based on quinoxaline derivative by a simple procedure reaction. 2,3-bis(6-bromopyridin-2-yl)-6-methoxyquinoxaline (BMQ) was fabricated and characterized using ATR-IR, 13C and 1H NMR, and Mass spectroscopy. The interaction of BMQ with Fe3+ caused a significant color change from colorless to yellow. The sensing complex BMQ-Fe3+ with high selectivity was described to be 1:1 by the molar ratio plot. In this experiment, iron was detected by naked-eye using a recently synthesized ligand (BMQ). This color change was unexpectedly observed in iron-overloaded plasma, which had previously been admitted by AAS (Atomic Absorption Spectroscopy). Normal plasma, however, did not exhibit this color change. Interestingly, Cu2+ ions cause a quench at the local emission around 565 nm. On the other hand, receptor-binding selectivity for Cu2+ over a wide linear concentration range was observed through changes in the emission spectra. BMQ-Cu2+ was characterized to be 1:1 by the Job's plot. The emission intensity of BMQ–Cu2+ complex was balanced within only 1 min. various mineral water samples were analyzed for detecting Cu2+. The results show the great potential of the developed probe BMQ for the sensing of Cu2+ ions in mineral and drinking water samples.

Effect of non-local hybrid functional on electronic band structure, manipulation of photocatalytic properties and optical response of Cu alloyed NaMgF3

In the context of eco-friendly renewable hydrogen energy production, it is imperative to compute the band edges positions and the effect of dopant concentration on the energy-harnessing capability of a designed photocatalyst. Ergo we investigated NaMgF3 fluoro-perovskite due to its novel and intriguing optical properties using Density functional theory (DFT). The impact of Cu on the band edge positions of NaMgF3, structural, electronic, and optical features is explored herein using Perdew-Burke-Ernzerhof generalized gradient approximation (GGA-PBE) and Ultrasoft pseudo potential (USSP) method. Electronic properties have been computed with Heyd–Scuseria– Ernzerhof (HSE03) hybrid functional to get experimentally comparable results, when sodium was replaced by Cu in NaMgF3 fluoro-perovskite up to 100%. The lattice parameters (a = b) show a quasi-linear increasing trend while alloying with Cu unlike the c-lattice parameter, which first increases and then decreases for Cu concentration above 40%. A cubic to pseudocubic tetragonal transition was also seen as a result of Cu inclusion at the Na site. The Bandgap enhancement of 7.393 eV is observed for HSE03 hybrid potential for pristine NaMgF3, in contrast with its GGA-PBE counterpart (5.75 eV). In addition, the band gap topology is found to be consistent for local and nonlocal hybrid potentials and shows decreasing trend upon alloying with Cu. The reduction in band gap infers the location of CBE just below the reduction edge of NHE for 33% Cu inclusion in NaMgF3 and hence is considered a suitable alloying concentration for the photodegradation of chemical dyes. Optical properties such as absorption, reflectivity, refractive index, dielectric function, and energy loss function were computed and an apparent red shift was observed after Cu inclusion. The static refractive index and dielectric function for pure NaMgF3 were found to be 1.45 and 1.95 respectively, and a linear behavior was observed after alloying in all optical parameters. Hence Cu alloyed NaMgF3 can possess possible future applications in optoelectronic and energy devices.

Research on synthesis of Cu<sub>3</sub>Mo<sub>2</sub>O<sub>9</sub>/MoO<sub>3</sub> nanocomposite and trimethylamine gas sensing properties

Aquatic products contain an incredibly high nutritional value for the human body and gradually become indispensable ingredients on the Chinese table. Trimethylamine (TMA) from the deterioration of aquatic products can serve as an indicator to measure fish freshness. It is a challenge to develop an instant, fast, convenient, and efficient gas sensor for fish freshness. In this study, a novel Cu<sub>3</sub>Mo<sub>2</sub>O<sub>9</sub>/MoO<sub>3</sub> composite gas sensing material is prepared by introducing Cu<sub>3</sub>Mo<sub>2</sub>O<sub>9</sub> nanoparticles on the surface of MoO<sub>3</sub> nanobelts. The results of SEM and TEM images show that the Cu<sub>3</sub>Mo<sub>2</sub>O<sub>9</sub> nanoparticles are uniformly dispersed. Then, the TMA sensing performance of a resistance-type gas sensor based the prepared Cu<sub>3</sub>Mo<sub>2</sub>O<sub>9</sub>/MoO<sub>3</sub> composite is tested at optimal operating temperature (240 °C). the results show that the sensor possesses good response (13.9) at low concentration (5×10<sup>–6</sup>), with excellent low detection limit (2×10<sup>–7</sup>). The response time is also significantly shortened. The high sensing performance of Cu<sub>3</sub>Mo<sub>2</sub>O<sub>9</sub>/MoO<sub>3</sub> composite is attributed to the heterojunction interface, which promotes the separation of electrons from holes through its strong oxygen adsorption and catalytic effect. This significantly improves the electron transport properties and gas sensing characteristics of the composite material. Electrons flow from MoO<sub>3</sub> nanoribbons to Cu<sub>3</sub>Mo<sub>2</sub>O<sub>9</sub>, and the Fermi level reaches equilibrium. This process results in the formation of an electron loss layer underneath MoO<sub>3</sub>, and the charge transfer channel narrows, which is consistent with previous result. When trimethylamine dissociates on the nanoribbons to release electrons, the balance of the fermi lever is disrupted, and electrons flow from MoO<sub>3</sub> to Cu<sub>3</sub>Mo<sub>2</sub>O<sub>9</sub>. As a result, the charge transfer channel becomes thinner, resulting in resistance modulation and increased sensitivity. In addition, the enhancement of trimethylamine sensing performance of Cu<sub>3</sub>Mo<sub>2</sub>O<sub>9</sub>/MoO<sub>3</sub> nanocomposite can be explained by the enhancement of gas adsorption and diffusion: MoO<sub>3</sub> nanoribbons as a skeleton can effectively disperse Cu<sub>3</sub>Mo<sub>2</sub>O<sub>9</sub> particles and increase the adsorption capacity of gas molecules. And the enhanced response of Cu<sub>3</sub>Mo<sub>2</sub>O<sub>9</sub>/MoO<sub>3</sub> may be due to the good catalytic effect of Cu<sub>3</sub>Mo<sub>2</sub>O<sub>9</sub>, which is conducive to oxygen adsorption. This work provides a new strategy for preparing high-performance MoO<sub>3</sub>-based gas sensing materials.

A Matter of Metals: Copper but Not Cadmium Affects the Microbial Alpha-Diversity of Soils and Sediments — a Meta-analysis

Heavy metal (HM) accumulation in soil affects plants and soil fauna, yet the effect on microbial alpha-diversity remains unclear, mainly due to the absence of dedicated research synthesis (e.g. meta-analysis). Here, we report the first meta-analysis of the response of soil microbial alpha-diversity to the experimental addition of cadmium (Cd) and copper (Cu). We considered studies conducted between 2013 and 2022 using DNA metabarcoding of bacterial and fungal communities to overcome limitations of other cultivation- and electrophoresis-based techniques. Fungi were discarded due to the limited study number (i.e. 6 studies). Bacterial studies resulted in 66 independent experiments reported in 32 primary papers from four continents. We found a negative dose-dependent response for Cu but not for Cd for bacterial alpha-diversity in the environments, only for Cu additions exceeding 29.6 mg kg−1 (first loss of − 0.06% at 30 mg kg−1). The maximal loss of bacterial alpha-diversity registered was 13.89% at 3837 mg kg−1. Our results first highlight that bacterial communities behave differently to soil pollution depending on the metal. Secondly, our study suggests that even extreme doses of Cu do not cause a dramatic loss in alpha-diversity, highlighting how the behaviour of bacterial communities diverges from soil macro-organisms.Graphical abstract

D-A-D based reversible fluorescent probe for selective detection and cell imaging of copper ion

Two D-A-D fluorescent probes ( X1 and X2 ) were constructed based on coumarin and 1,3,4-thiadiazole moieties and were used for visual inspection and fluorescent response of Cu 2+ . Both of them demonstrated high selectivity and sensitivity towards Cu 2+ in DMSO-Tris-HCl solution (v/v 3:1, pH = 7.4) through distinct fluorescence and colorimetric variation. The detection limits of X1 and X2 were achieved at 13.6 nM and 12.3 nM. Furthermore, they were proven to be reversible sensors by addition of EDTA into X1/X2 + Cu 2+ solution and were actually applied to test paper inspection and cell imaging. Density functional theory calculations were employed to guide experiments in the development of probes and exploration of detecting mechanism.

Potentiometric determination of copper(II) ions based on a porphyrin derivative

AbstractA novel poly(vinyl chloride; PVC) membrane‐based Cu(II)–selective sensor has been developed using synthesized 5,10,15,20‐tetrakis(4‐methoxycarbonylphenyl)porphyrin as an ionophore. The Cu(II)–selective sensor exhibits a Nernstian response for Cu(II) ion over a wide concentration range of 1.0 × 10−5 to 1.0 × 10−1 mol L−1 with the slope of 27.0 ± 2.5 mV/decade, and a lower limit of detection of 1.88 × 10−6 mol L−1. The novel sensor shows good repeatability and high selectivity for Cu(II) ions over other mono‐, bi‐ and trivalent cations. The sensor potential response remains unaffected by pH in the range of 4.4–10.6 and exhibits a fast response time of less than 10s. Finally the developed Cu(II)–selective sensor has been successfully used as an indicator electrode in the potentiometric titration of Cu2+ against ethylenediaminetetraacetic acid and also in the determination of Cu(II) ion concentration in different water and beverage samples.

Response of fungi-microalgae pellets to copper regulation in the removal of sulfonamides and release of dissolved organic matters

Both sulfonamides (SAs) and copper (Cu(II)) were frequently detected together in swine wastewater. In this study, the regulation of Cu(II) on SAs adsorption and release of dissolved organic matters (DOMs) by fungi-microalgae pellets (FM-pellets) were investigated. Aspergillus oryzae pellets were prepared for combination with Chlorella vulgaris and the optimal conditions were at agitation speed of 130 rpm, fungi to microalgae ratio of 10:1 and the combined time of 3 h with the highest combination efficiency of 98.65%. The results showed that adsorption was the main mechanism for SAs removal. FM-pellets exhibited a high SAs adsorption potential within 6 h, and the adsorption capacity of sulfamethazine (SMZ), sulfamonomethoxine (SMM) and sulfamethoxazole (SMX) was 1.07, 0.94 and 1.67 mg/g, respectively. Furthermore, the removal of SMX, SMZ and SMM was greatly promoted from 62.31% to 85.21%, 58.71–67.91% and 64.17–80.31%, respectively, under the presence of 2 mg/L Cu(II) through ion exchange and adsorption bridging. DOMs were analyzed by the parallel factor (PARAFAC) to demonstrate the response mechanism of FM-pellets to Cu(II). Protein-like substances and NADH in DOMs released by FM-pellets formed complexes with Cu(II) to alleviate the damage on the organism. These findings provide new insights into the mechanism and response of Cu(II) in the removal of SAs by FM-pellets.

Sources and levels of copper affect liver copper profile, intestinal morphology and cecal microbiota population of broiler chickens fed wheat-soybean meal diets

Super dosing copper (Cu) has long been used as an alternative to antibiotic growth-promoters in broiler chickens’ diet to improve gut health. This study was designed to compare nutritional and growth-promoting levels of Cu hydroxychloride (CH) with CuSO4 on gut health bio-markers and liver mineral profile of broiler chickens. Ross 308 chicks (n = 864) were randomly assigned to eight treatments, as basal diet containing no supplemental Cu; the basal diet with 15 or 200 mg/kg Cu as CuSO4; or 15, 50, 100, 150 or 200 mg/kg Cu from CH. The highest liver Cu content was observed in birds fed the diets with 200 mg/kg CuSO4 (P < 0.01). Serum FITC-d concentration as the leaky gut marker, and liver malondialdehyde concentration were not affected. Copper level or source had no effect on cecal short chain fatty acid and the mRNA expression of five jejunal genes involved in gut integrity. Negative linear responses of Cu were observed on Lactobacillus (P = 0.032), Bacteroides (P = 0.033), and Enterobacteriaceae (P = 0.028) counts. The jejunal villus height increased in birds fed CH at 200 and 100 mg/kg (P < 0.05). Increasing Cu levels, linearly and quadratically (P < 0.001), increased Cu excretion.

Fluorescent carbon dots crosslinked cellulose Nanofibril/Chitosan interpenetrating hydrogel system for sensitive detection and efficient adsorption of Cu (II) and Cr (VI)

• One-pot synthesis of carbon dots cross-linked cellulose nanofibril hydrogel. • The introduction of chitosan by solvent displacement forms IPN hydrogel. • Carbon dots provide visual detection during Cu (II) and Cr (VI) adsorption. • Amphoteric biomass and carbon dots provide adsorption sites for Cu (II) and Cr (VI). • The mechanism of Cu (II) and Cr (VI) sorption and sensing was determined. To address the pollution of heavy metal ions in water resources, a novel self-assembled nitrogen-doped carbon dots (NCDs) crosslinked, cellulose nanofibril (CNF) and chitosan (CS) based interpenetrating polymer network (IPN) hydrogel (NCDs-CNF/CSgel) was prepared for simultaneous fluorescent detection and adsorption of Cu (II) cation and Cr (VI) anion. The NCDs cross-linked CNF hydrogel network was synthesized by an environmentally friendly low-temperature hydrothermal process and subsequently, solvent replacement was used to form the second layer of CS network. The morphology, chemical structure, fluorescent properties, and adsorption behaviors of NCDs-CNF/CSgel were analyzed. The results showed that NCDs-CNF/CSgel exhibited a wide linear range of fluorescence response for Cu (II) (50–1000 mg/L, detection limit of 40.3398 mg/L) and superior sensitivity and selectivity of fluorescence response for Cr (VI) (linear range of 1–50 mg/L, detection limit of 0.7093 mg/L). NCDs-CNF/CSgel showed high adsorption capacities of 148.30 mg/g and 294.46 mg/g for Cu (II) and Cr (VI), respectively, and fitted well to the pseudo-second-order model and the Langmuir model. The detection of Cu (II) and Cr (VI) and their adsorption mechanisms onto NCDs-CNF/CSgel were further determined. Hence, this work provides a green and sustainable approach for the synthesis of a functional material which can be applied for the detection and adsorption of heavy metal ions.

Development of a new electrochemical method for the determination of copper(ii) at trace levels in environmental and food samples.

This paper presents the fabrication of a new modified carbon paste electrode (CPE) with N 1-hydroxy-N 1,N 2-diphenylbenzamidine (HDPBA) and functionalized multi-walled carbon nanotubes (MWCNTs) (HDPBA-MWCNTs/CPE) for highly sensitive and selective determination of Cu(ii) using the square wave anodic stripping voltammetry (SWASV) technique. The fabricated electrode was characterized using various spectroscopic techniques to study its morphological, structural, and electrochemical properties. The accumulation of Cu(ii) on the surface of HDPBA-MWCNTs/CPE was done in 0.1 M ammonium chloride (NH4Cl, pH 5) solution at an applied potential of -0.70 V versus Ag/AgCl for 180 s, followed by electrochemical stripping in the positive scan of the voltammetry after a resting time of 10 s. The developed HDPBA-MWCNTs/CPE was found to be highly selective, sensitive and reproducible. At optimal conditions of the experiment, the proposed method exhibited a very low limit of detection (0.0048 nM Cu(ii)), a wide linear dynamic range (0.00007-1.5000 μM Cu(ii)), and good reproducibility with relative standard deviation (RSD) value of 3.7%. The effect of various foreign ions on the voltammetric response of Cu(ii) was investigated and the electrode was found to be highly selective to Cu(ii). The practical applicability of the proposed HDPBA-MWCNTs/CPE was studied by applying the electrode for the quantification of Cu(ii) contents in environmental water (wastewater and tap water), soft drink (Fanta and Sprite), and food supplement (commercially available multi-mineral/vitamin tablets) samples. The present method was validated with atomic absorption spectrometry (AAS). The results found from the two methods are in good agreement with a 95% confidence level.

Triazole-tethered naphthalimide-ferrocenyl-chalcone based voltammetric and potentiometric sensors for selective electrochemical quantification of Copper(II) ions

• A ferrocene based TNFC was synthesized and found sensitive towards Cu 2+ . • UV, fluorescence, DFT, NMR and HRMS studies confirmed binding of TNFC with Cu 2+ . • TNFC exhibited voltammetric response towards Cu 2+ with LOD 0.09 µM. • TNFC -CPE showed a Nernstian slope of 30.0 mV/decade with LOD 0.79 µM. • TNFC -CPE was successfully applied for estimation of Cu 2+ in water and milk products. A triazole-tethered naphthalimide-ferrocenyl-chalcone ( TNFC ) derivative was synthesized and investigated for its electrochemical behavior with subsequent successful application as a receptor for the development of differential pulse voltammetric (DPV) and potentiometric sensors for quantification of Cu 2+ after receiving confirmatory evidences from UV–Vis, Fluorescence and DFT studies. Cyclic voltammogram of TNFC exhibited two redox peaks at +0.51 V and +0.59 V corresponding to ferrocene/ferrocenium ion redox couple in the potential range of 0–1.0 V vs Ag/Ag + . On addition of Cu 2+ , Cyclic voltammogram of TNFC shifted toward more positive potential (anodic shift), indicating the formation of TNFC -Cu 2+ complex. DPV sensor demonstrated a selective response towards Cu 2+ in the concentration range of 0–26 µM with detection limit of 0.09 µM. The TNFC modified carbon paste electrode (CPE) exhibited a selective response for Cu 2+ with Nernstian slope of 30.0 mV/decade in the concentration range of 1.0 × 10 −6 −1.0 × 10 −1 M and detection limit 0.79 µM. High binding constant (3.2 × 10 4 M −1 ) and negative value of Gibbs free energy (−25.69 kJmol −1 ) calculated using Benesi-Hildebrand (BH) equation confirmed the favorable complexation between TNFC and Cu 2+ which was also validated using 1 H NMR and mass spectrometry. The proposed TNFC- CPE was successfully utilized for quantification of Cu 2+ content in real samples of water and milk products.

Copper(II) complexes of 1,3-dimethyl-5-(4′/3′-pyridylazo)-6-aminouracil: Structures, redox, magnetic and protein binding properties

Two new monomeric copper(II) complexes based on 1,3-dimethyl-5-(4′/3′-pyridylazo)-6-aminouracil (HL1: 4′-pyridylazo, complex 1: cis-CuIIL12.MeOH; HL2: 3′-pyridylazo, complex 2: cis-CuIIL12.H2O) were synthesized, characterized and investigated for redox, magnetic and protein-binding properties. The complex 1 is in monoclinic space group C2/c, Z = 4 whereas the complex 2 is in triclinic space group P-1, Z = 2. The complexes hold similar structure in solid and solution state as could be infered from the EPR spectra of 1 having well-resolved hyperfine features, g|| > g┴ > ge (g|| =2.20 and g┴ =2.05). The E½ values for oxidative response of Cu(III)/Cu(II) couple are 1.030 V (ΔE = 133 mV) for 1 and 0.982 V (ΔE = 128 mV) for 2, indicating high redox stability of Cu(II) ions in the complex environment. Direct current (DC) variable-temperature magnetic susceptibility measurements on polycrystalline sample of 1 were carried out in the temperature range 1.8-300 K. The magnetic behavior indicates a weak antiferromagnetic interaction between Cu(II) ions in the crystal lattice below 25 K. The study of Bovin Serum Albumin (BSA)-complex interactions reveals that the BSA binds the complexes through the sites of tryptophan residues in 1:1 manner (n = 0.9007 & KA = 1.482 × 104M−1 for 1 and 0.7433 & KA =2.394×103M−1 for 2). Thus, the developed complexes could be treated as muti-functional materials.