NiO@CuO@Cu bilayered electrode: two-step electrochemical synthesis supercapacitor properties

Present work deals with a two-step synthesis and electrochemical properties of nickel oxide @copper oxide@copper (NiO@CuO@Cu) bilayered electrode. In the first step, anodization (40 V for 25 min) of Cu foil has been carried out for forming Cu-hydroxide@Cu which when annealed at 300 °C for 1 h produces CuO@Cu. In the second step, Ni-hydroxide is deposited onto CuO@Cu by applying current density of 0.03 A/cm² for 3 min which when re-annealed at 300 °C for 1 h gives out NiO@CuO@Cu bilayered electrode. Obtained NiO@CuO@Cu bilayered electrode demonstrates separate CuO and NiO phases. The electrochemical properties have obtained using cyclic voltammetry, galvonostatic charge-discharge, and Nyquist plot measurements that reveal an importance of NiO@CuO@Cu as a potential electrode material in the electrochemical supercapacitor application with 58.14, 51.25, and 4.73 F g^?1 values in 0.5 M, NaOH, KOH, and Na₂SO₄ electrolytes, respectively, measured at 2 mVs^?1 scan rate.     

Novel core-corona hybrid nanomaterials based on the conjugation of amphiphilic polymeric diblocks to the surface of multifunctional nanodiamond anchors

The poor aqueous solubility and the physicochemical instability of many marketed drugs and new chemical entities is one of the most challenging issues in pharmaceutical research and development. Polymeric micelles (PMs) are produced by the self-assembly of polymeric amphiphiles and they represent one of the most extensively investigated nanotechnology platforms for encapsulation, delivery and targeting of hydrophobic drugs. However, a main challenge is preventing their disassembly under extreme dilution in the body fluids, which leads to uncontrolled release of the encapsulated cargo. In this work, we developed an amphiphilic nanomaterial that resembles the core-corona architecture of a PM with superior stability in the body fluids. Specifically, we utilized carboxylated nanodiamonds (cNDs) as particulate anchors to covalently link amphiphilic diblock copolymers consisting of poly(epsilon-caprolactone) (PCL) and poly(ethylene glycol) monomethyl ether (PEG) as hydrophobic and hydrophilic components, respectively. We confirmed a successful core-corona nanostructure using various characterization techniques. In addition, TEM revealed the presence of a thin polymeric layer. Then, the cell compatibility was evaluated in Caco2 cell monolayers, an in vitro model of the intestinal epithelium. Finally, the encapsulation of the hydrophobic anti-helmintic drug nitazoxanide was studied. Cargoes as high as 17.5% w/w were achieved and the sustained release of the cargo according to the Korsmeyer-Peppas model demonstrated in vitro. Overall, preliminary results highlight the potential of this novel approach to extend the applicability of PMs in drug delivery.     

A coumarin-based fluorescent PET sensor utilizing supramolecular pKa shifts

A new coumarin derivative containing benzothiazole and piperazine substituents was synthesized. Preferential inclusion of the benzothiazole group, over the coumarin and piperazine groups, inside the cavity of the molecular container cucurbit[7]uril (CB7) was evidenced by using optical and NMR techniques. The binding constant of the new complex with CB7 is higher in its protonated forms (e.g., K = 2.8 × 10⁶ M⁻¹) than in its neutral forms, which led to an increase in the pK_a value associated with protonation of the aza nitrogen on the benzothiazole ring of ca. 2.5 units. Such CB7-induced protonation disabled the photoinduced electron transfer (PET) in the included molecule, enhancing its coumarin fluorescence up to ca. 45-fold (pH 3.5, 410 nm). The results are discussed in the context of designing sensitive analytical tools for reversible monitoring of optically inactive analytes by competitive displacement experiments.     

Quenching of the luminescence of upconverting luminescent nanoparticles by heavy metal ions

We report that the luminescence of upconverting luminescent nanoparticles (UCLNPs) is quenched by heavy metal ions and halide ions in aqueous solution. The UCLNPs consist of hexagonal NaYF₄ nanocrystals doped with trivalent rare earth ions and were synthesized by both the oleic acid (solvothermal) method and the ethylenediaminetetraacetic acid (co‐precipitation) method. Quenching was studied for the Cu^II, Hg^II, Pb^II, Cd^II, Co^II, Ag^I, Fe^III, Zn^II, bromide, and iodide ions and is found to be particularly strong for Hg^II. Stern–Volmer plots are virtually linear up to quencher concentrations of 10–25 mM , but deviate from linearity at higher quencher concentrations, because static quenching causes an additional effect. The UCLNPs display two main emission bands (blue, green, red or near‐infrared), and the quenching efficiencies for these are found to be different. The effect seems to be generally associated with UCLNPs because it was observed for all UCLNPs doped with trivalent lanthanide ions including Yb^III, Er^III, Ho^III, and Tm^III. The results are discussed in terms of quenching mechanisms and with respect to potential applications such as optical sensing.     

Reassignment of the structures of products produced by reactions of the product believed to be 2-(1-phenyl-2-thiocyanatoethylidene)-malononitrile with electrophiles

The reactivity of the product believed to be 2-(1-phenyl-2-thiocyanato-ethylidene)malononitrile toward a variety of electrophilic and nucleophilic reagents is reported.     

Hollow fiber liquid phase microextraction as a preconcentration and clean-up step after pressurized hot water extraction for the determination of non-steroidal anti-inflammatory drugs in sewage sludge

A method for the quantitative determination of non-steroidal anti-inflammatory drugs (NSAIDs) in sewage sludge was developed and validated. The target compounds were extracted using pressurized hot water extraction (PHWE) and then purified and preconcentrated by three-phase hollow fiber liquid phase microextraction (HF-LPME) followed by LC–ESI-MS analysis. The PHWE was optimized with regard to the pH of solvent as well as other operational parameters. The optimum conditions were 0.01 M NaOH as the extraction solvent, temperature of 120 °C, pressure of 100 bar, static time 5 min, 5 cycles, flush volume 90% and purge time 60 s. Spike recoveries for sludge samples spiked at 200 ng g⁻¹ were in the range of 101–109% but for the native drugs in non-spiked sludge samples, recoveries were 38.9%, 59.8%, 90.3% and 47.8% for ketoprofen, naproxen, diclofenac and ibuprofen, respectively. Donor phase pH, ionic strength and extraction time were optimized for HF-LPME after PHWE. The optimum conditions were 2 h extraction at pH 1.5 without salt addition. Enrichment factors in the range of 947–1213 times were achieved (extraction recoveries were 23.6–30.3%) for HF-LPME after PHWE. The matrix effect on the ionization of drugs in LC–ESI-MS was also investigated. The results show that there is a smaller matrix effect (−8.9% to +14.6%) in comparison with other published values obtained using solid phase extraction (SPE) for clean-up after pressurized liquid extraction (PLE). Method detection limits (MDLs) and method quantification limits (MQLs) for different drugs were in the range of 0.4–3.7 ng g⁻¹ and 1.5–12.2 ng g⁻¹ in dried sludge samples, respectively. The characteristics of the proposed method were compared with those of other published works. The considerably lower ion suppression/enhancement and minimum use of organic solvents (a few microliters of di-n-hexyl ether) in the sample preparation step are two highlighted advantages of the proposed method in comparison with previously published works. The method was applied to determine NSAIDs in sewage sludge from Källby wastewater treatment plant (Lund, Sweden) in April, June, August and October 2010. The highest concentration level was recorded for ibuprofen in the April sewage sludge sample (588 ng g⁻¹) and all of the selected NSAIDs were detected in all the samples analyzed.     

Study and fabrication of europium picrate triethylene glycol complex

A mononuclear of [Eu(NO3)(Pic)(H2O)2(EO3)](Pic)·(0.73)H2O complex, where EO3=trietraethylene glycol and Pic=picrate anion, shows a red emission when used as an active layer in a single layer of ITO/EO3-Eu-Pic/Al configuration. The crystal structure of the complex consists of [Eu(NO3)(Pic)(H2O)2(EO3)]+ cation and [Pic]- anion. The Eu(III) ion is coordinated to the 10 oxygen atoms from one EO3 ligand, one Pic anion, one nitrate anion, and two water molecules. The complex is crystallized in triclinic with space group P-1. The hybrids in thin films I and II were prepared in the respective order solution concentrations of 15 and 20 mg/mL the emissive center. Comparing the photoluminescence (PL) and electroluminescence (EL) spectra, we can find that all emissions come from the characteristic transitions of the Eu(III) ion. The EL spectra of both thin films showed the occurrence of the most intense red-light emission around at 612 nm. Comparison of organic light-emitting device (OLED) current intensity characteristics as a function of voltage (I-V) show that the thin film I is better than those found for the thin film II. The thickness of the emitting layer is an important factor to control the current-voltage curve. The sharp and intense emission of the complex at low voltage indicates that the complex is a suitable and promising candidate for red-emitting materials.     

Reactions of some new thienothiophene derivatives

Facile and convenient syntheses of bisdimethylthieno[2,3-b]thiophen-2,5-diyl bis(oxazole-2-amine), bis(1H-imidazol-2-amine), bis((3a)-H-indole),[1,2-a]pyrimidine), bis(1H-imidazo[1,2-b][1,2,4]triazole) and bis(9H-benzo[d]imidazo[1,2-a]imidazole) derivatives incorporating a thieno[2,3-b]thiophene moiety from the versatile and readily accessible 1,1'(3,4-dimethylthieno[2,3-b]thiophene-2,5-diyl)-bis(2-bromo-ethanone) (1) are described.     

Theoretical study on the reaction of hydrogen atoms with aniline

The reaction of aniline with hydrogen atom is investigated herein using the hybrid meta-DFT functional of BB1 K. Hydrogen atom is found to preferentially add at an ortho position. However, the fate of the o-(C₆H₅NH₂)H adduct is found to be solely the deactivation of the initial addition channel. The rate constant for the abstraction channel (C₆H₅NH₂ + H → C₆H₅NH + H₂) is fitted by the expression 1.10 × 10⁻¹¹ exp(−4,200/T) cm³ molecule⁻¹ s⁻¹. Our calculated rate constant for the abstraction channel agrees very well with the available experimental measurements. Satisfactory agreement is found between calculated and experimental measurements for the displacement channel (C₆H₅NH₂ + H → C₆H₆ + NH₂). Our detailed analysis for the corresponding displacements in toluene and phenol suggests that the three systems exhibit similar behavior with regard to the relative importance of abstraction and displacement channels.