Synthesis,molecular conformation,vibrational, electronic transition,and chemical shift assignments of 4-(thiophene-3-ylmethoxy)phthalonitrile: a combined experimental and theoretical analysis

This work presents the synthesis and characterization of a novel compound, 4-(thiophene-3-ylmethoxy)phthalonitrile (TMP). The spectroscopic properties of the compound were examined by FT-IR, FT-Raman, NMR, and UV techniques. FT-IR and FT-Raman spectra in solid state were observed in the region 4000–400 cm⁻¹ and 3500–50 cm⁻¹, respectively. The ¹H and ¹³C NMR spectra were recorded in CDCl₃ solution. The UV absorption spectrum of the compound that dissolved in THF was recorded in the range of 200–800 nm. The structural and spectroscopic data of the molecule in the ground state were calculated using density functional theory (DFT) employing B3LYP exchange correlation and the 6-311++G(d,p) basis set. The vibrational wavenumbers were calculated and scaled values were compared with experimental FT-IR and FT-Raman spectra. The complete assignments were performed on the basis of the experimental results and total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method. Isotropic chemical shifts (¹³C NMR and ¹H NMR) were calculated using the gauge-invariant atomic orbital (GIAO) method. A study on the electronic properties, such as HOMO and LUMO energies, were performed by time-dependent DFT (TD-DFT) approach. The HOMO and LUMO analyses have been used to elucidate information regarding charge transfer within the molecule. Comparison of the calculated frequencies, NMR chemical shifts, absorption wavelengths with the experimental values revealed that DFT method produces good results.     

Natural Melanin Nanoparticle‐decorated Screen‐printed Carbon Electrode: Performance Test for Amperometric Determination of Hexavalent Chromium as Model Trace

A biosensor was prepared with natural melanin nanoparticles (MNP) decorated on a screen‐printed carbon electrode (SPCE). Hexavalent chromium was selected as a well‐known heavy metal ion to be detected for testing the performance of novel biosensor. Natural MNP was extracted from cuttlefish (Sepia officinalis) ink. Surface decoration of SPCEs with MNP was performed by two different methods. The first one was layer‐by‐layer assembly (LBL‐A) for different cycle times(n). In the second one, plasma treatment of SPCE incorporated with evaporation‐induced self‐assembly (EI‐SA) techniques including different incubation times in MNP solutions. The performance of both modified SPCEs were tested for amperometric detection of Cr(VI) in various water samples, and peak reduction of Cr(VI) was determined at 0.33 V. Amperometric results showed wide linear ranges of 0.1–2 μM and 0.1–5 μM of Cr(VI) for SPCEs modified with 14n‐LBL‐A and 12h‐EI‐SA, respectively. The sensitivities of SPCEs modified with 14n‐LBL‐A and 12h‐EI‐SA techniques were 0.27 μA μM^?1 and 0.52 μA μM^?1, respectively. In addition, both modified SPCEs selectively detected Cr(VI) in a model aqueous system composed of certain other heavy metals and minerals, and tap and lake water samples. The LOD and LOQ values for 12h‐EI‐SA were 0.03 μM and 0.1 μM, respectively. This showed that MNP‐modified‐SPCEs generated via EI‐SA techniques have the potential to be an alternative to conventional detection methods such as ICP‐MS.     

Thermal characterization of Er-doped and Er–Gd co-doped ceria-based electrolyte materials for SOFC

Ce_1?xEr_xO₂ and Ce_1?2xEr_xGd_xO₂ co-doped ceria electrolyte nanopowder materials were successfully prepared by sol–gel method. Depending on the temperature, the crystal structure changes were analyzed by X-ray diffraction. It was observed that the crystal size of the electrolytes decreased depending on the temperature and the time. X-ray diffraction results confirmed cubic fluorite structure in the samples. The microstructural properties of the samples were analyzed by scanning electron microscopy, and thermal stability measurement was performed by thermogravimetric and differential thermal analyses. The total electrical conductivity of the nanopowder electrolytes was determined by the dc four-point probe technique in air at temperatures ranging from room temperature to 1373 K. The four-probe conductivity results revealed that Ce_0.8Er_0.1Gd_0.1O₂ has a higher ionic conductivity compared to Ce_0.83Er_0.17O₂ at 1123 K. The four-probe conductivity results show that both Ce_1?xEr_xO₂ and Ce_1?2xEr_xGd_xO₂ solid electrolytes have potential application to oxide ionic conductor for solid oxide fuel cells.     

Metabolomics and Physiological Insights into the Ability of Exogenously Applied Chlorogenic Acid and Hesperidin to Modulate Salt Stress in Lettuce Distinctively

Recent studies in the agronomic field indicate that the exogenous application of polyphenols can provide tolerance against various stresses in plants. However, the molecular processes underlying stress mitigation remain unclear, and little is known about the impact of exogenously applied phenolics, especially in combination with salinity. In this work, the impacts of exogenously applied chlorogenic acid (CA), hesperidin (HES), and their combination (HES + CA) have been investigated in lettuce (Lactuca sativa L.) through untargeted metabolomics to evaluate mitigation effects against salinity. Growth parameters, physiological measurements, leaf relative water content, and osmotic potential as well as gas exchange parameters were also measured. As expected, salinity produced a significant decline in the physiological and biochemical parameters of lettuce. However, the treatments with exogenous phenolics, particularly HES and HES + CA, allowed lettuce to cope with salt stress condition. Interestingly, the treatments triggered a broad metabolic reprogramming that involved secondary metabolism and small molecules such as electron carriers, enzyme cofactors, and vitamins. Under salinity conditions, CA and HES + CA distinctively elicited secondary metabolism, nitrogen-containing compounds, osmoprotectants, and polyamines.     

A novel amperometric glucose biosensor based on poly(glycidyl methacrylate-co-(3-thienylmethylmethacrylate))

Two novel glucose oxidase (GOx) enzyme electrodes based on the copolymer of glycidyl methacrylate with 3-thienylmethyl methacrylate (poly(GMA-co-MTM)) with and without polypyrrole (PPyr) coating were prepared and employed in the amperometric determination of glucose levels. The effect of PPyr coating on the electrode properties was investigated in detail. Cyclic voltammetry studies showed that electrical conductivity of electrode B with PPyr coating (poly(GMA-co-MTM)/GOx/PPyr) was substantially higher than that of electrode A (poly(GMA-co-MTM)/GOx). On the other hand, electrode A showed better results in terms of sensitivity (10 nA/mM), limit of detection (50.2 μM), and response time (5 s). Electrodes A and B gave linear responses to the glucose concentrations in the range of 2–20 and 2–14 mM, respectively. The ranges of linearity for both enzyme electrodes are sufficient for the determination of physiological glucose concentrations in human blood. Moreover, PPyr coating of electrode B did not result in further stabilization of the enzyme electrode.     

Complexity from Simplicity: Unique Polymer Capsules,Rods, Monoliths,and Liquid Marbles Prepared via HIPE in Microfluidics

Existing methods for preparing complex particles, i.e., hollow porous, depend on either multiple steps or a complex reactor design. Here, a straightforward method to prepare unique polymer particles with complex shapes via the use of simple equipment and readily available chemicals is reported. Beads, capsules, and rods with uniform size and interconnected pores are obtained through the formation of high internal phase emulsion (HIPE) droplets in a microfluidic channel. The method is applicable to a broad range of (meth)acralates. Controlling physical properties, such as viscosity and emulsion stability, is key to control the shape of the resulting particles. Post‐modification of the particles via click chemistry, their application in liquid marble formation, and their use as droplet reactors are also demonstrated.     

Asymmetric synthesis of aminocyclooctenecarbonitriles: Cyclooctene β-lactam and hydroxyaminocyclooctene carboxylic precursors

Enantiopure β-aminocyclooctenenitriles, as precursors of β-amino acids and β-lactams, were synthesized from a readily available chloroalkene nitrile and (S)-methylbenzylamine via a straightforward substitution reaction and purified by crystallization. Acidic hydrolysis of the nitrile groups to their corresponding amides followed by DCC assisted carbonyl group activation gave novel α,β-unsaturated lactams. The treatment of 3-bromo-8-chlorocyclooctenecarbonitrile with (S)-methylbenzylamine furnished a diastereomeric mixture of bromoaminocyclooctenecarbonitriles via an S_N2′ pathway rather than bromide substitution via an S_N2 pathway. The diastereomeric mixture of bromoaminocyclooctanecarbonitriles provided two novel aziridines upon heating. TFA catalyzed aziridine ring opening gave γ-hydroxyl-β-aminocyclooctenecarbonitriles and γ-amino-β-hydroxycyclooctenecarbonitriles.     

Star polymers by photoinduced copper‐catalyzed azide–alkyne cycloaddition click chemistry

Well‐defined star polymers consisting of tri‐, tetra‐, or octa‐arms have been prepared via coupling‐onto strategy using photoinduced copper(I)‐catalyzed 1,3‐dipolar cycloaddition click reaction. An azide end‐functionalized polystyrene and poly(methyl methacrylate), and an alkyne end‐functionalized poly(ε‐caprolactone) as the integrating arms of the star polymers are prepared by the combination of controlled polymerization and nucleophilic substitution reactions; whereas, multifunctional cores containing either azide or alkyne functionalities were synthesized in quantitatively via etherification and ring‐opening reactions. By using photoinduced copper‐catalyzed azide–alkyne cycloaddition (CuAAC) click reaction, reactive linear polymers are simply attached onto multifunctional cores to form corresponding star polymers via coupling‐onto methodology. The chromatographic, spectroscopic, and thermal analyses have clearly demonstrated that successful star formations can be obtained via photoinduced CuAAC click reaction. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 1687–1695