Electrochemical sensors and biosensors based on heterogeneous carbon materials

Abstract  An overview of the use of electrochemical sensors made from heterogeneous carbon materials (carbon paste electrodes, screen-printed carbon electrodes) in the field of food analysis is presented. Sensors for inorganic and organic analytes as well as biosensors are summarized. Graphical abstract        

Micro-solid oxide fuel cells: status,challenges, and chances

Abstract  Micro-solid oxide fuel cells (micro-SOFC) are predicted to be of high energy density and are potential power sources for portable electronic devices. A micro-SOFC system consists of a fuel cell comprising a positive electrode-electrolyte-negative electrode (i.e. PEN) element, a gas-processing unit, and a thermal system where processing is based on micro-electro-mechanical-systems fabrication techniques. A possible system approach is presented. The critical properties of the thin film materials used in the PEN membrane are discussed, and the unsolved subtasks related to micro-SOFC membrane development are pointed out. Such a micro-SOFC system approach seems feasible and offers a promising alternative to state-of-the-art batteries in portable electronics. Graphical abstract  Graphical Abstract text      

Ultra-thin emissive molecular devices: polarized emission of Ln(III) complex films

Abstract  On ultra-thin films, Tb(III) shows polarized ff-emission in the visible wavelength region induced by intramolecular energy transfer from the photoexcited organic ligand, such as phenanthroline. Pr(III) causes polarized ππ* emission from the chromophore in the ultra-thin film (Langmuir–Blodgett film). Here, the unique optical properties of molecular devices with lanthanide complexes are summarized. Graphical Abstract        

Soft matter lithium salt electrolytes: ion conduction and application to rechargeable batteries

Abstract  Soft matter provides diverse opportunities for the development of electrolytes for all solid state lithium batteries. Here we review soft matter solid electrolytes for lithium batteriesthat are primarily obtained starting from liquid electrolytic systems. This concept of solid electrolyte synthesis from liquid is significantly different from prevalent approaches. The novelty of our approach is discussed in the light of various fundamental issues and in relation to its application to rechargeable lithium batteries. Graphical abstract   M. Patel and S. K. Das have contributed equally to the work.     

Practical and general method for the direct synthesis of alkyl fluorides from alcohols under mild conditions: a reinvestigation

Abstract  In contrast to the results presented in a previous report, the direct conversion of alcohols to alkyl fluorides with triphenylphosphine and potassium fluoride in CCl₄/DMF under mild conditions failed. Graphical Abstract        

Structure and conductivity in CeNb<Subscript>3</Subscript>O<Subscript>9-δ</Subscript>

Abstract  In the search of new materials for solid oxide fuel cells, a study of the structure and electrical conductivity of Mg-doped and nominally pure CeNb₃O_9-δ was undertaken. This material exhibits an orthorhombic crystal structure as determined by Rietveld refinement. Through a combined study of 4-point DC and AC impedance spectroscopy, it was determined that the material presents oxygen ion conductivity, electron conductivity and electron-hole conductivity according to the partial pressure of oxygen and temperature in agreement with a simple defect chemistry model. Finally, some experiments seem to indicate the presence of proton conduction. Graphical Abstract        

Use of 3D QSAR to investigate the mode of binding of pyrazinones to HIV-1 RT

Abstract  Comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) based on the docked conformation were performed for 24 pyrazinone derivatives. All compounds were docked into the wild-type HIV-1 RT binding pocket and the lowest-energy docked configurations were used to construct the 3D QSAR models. The CoMFA and CoMSIA models enable good prediction of inhibition by the pyrazinones, with  = 0.703 and 0.735. Results obtained from CoMFA and CoMSIA based on the docking conformation of the pyrazinones are, therefore, powerful means of elucidating the mode of binding of pyrazinones and suggesting the design of new potent NNRTIs. Graphical Abstract        

Interaction of push–pull <Emphasis Type="Italic">tert-</Emphasis>enamines with phenylglyoxal

Abstract  The reaction of push–pull enamines with 1,2-biselectrophilic phenylglyoxal was investigated. Phenylglyoxal was found to react depending on the structure of the push–pull enamine, affording either a hydroxyalkylation product at the methyl group or the cyclic product via participation of the methyl group and the β-carbon of the enamine. Graphical abstract        

A highly efficient and ecofriendly procedure for tetrahydropyranylation of alcohols and phenols in the presence of in-situ generated I2 under heterogeneous and neutral conditions

Abstract  Molecular iodine generated in situ from Fe(NO₃)₃·9H₂O/NaI acts as a highly efficient catalyst for tetrahydropyranylation of various alcohols and phenols with 3,4-dihydro-2H-pyran in almost quantitative yields. The reaction occurs rapidly in dichloromethane at room temperature, and use of toxic molecular iodine is avoided. Graphical Abstract        

Synthesis and study of the fluorescent behavior of 3-pyridinecarbonitriles

Abstract  A series of (2E)-3-(1-chloro-6-methoxy-3,4-dihydronaphthalen-2-yl)-1-(4-aryl)prop-2-en-1-ones (chalcones) have been synthesized by a new synthetic route. The 3-pyridinecarbonitrile derivatives were synthesized by the Michael reaction of malononitrile (in base) and aroylacetonitriles (in acid) with chalcones in one pot. The fluorescent properties and quantum yields of these compounds were studied. Graphical Abstract        

An atomistic simulation study of oxygen-vacancy migration in perovskite electrolytes based on LaGaO3

Abstract  Static lattice simulation techniques were used to calculate the energetic barriers for oxygen-vacancy migration in the perovskite-type oxide LaGaO₃ substituted with alkaline earth cations. The calculated migration energies are found to vary with the number and size of the substituting cations in the immediate neigbourhood of the migrating defect. It is argued that not only the size but also the charge of the cations constituting the saddle-point configuration play a role in determining the migration energy. Graphical abstract        

Immunochemical tools for mycotoxin detection in food

Abstract  As a result of the deleterious effects of mycotoxins on human and animal health, and the consequently increasing stringency in the determination of food contamination levels, many researchers have focused their efforts on developing new devices for the detection of these compounds. Biosensors merit special mention due to their sensitivity, accuracy, cost-effectiveness and simplicity, not only of the construction, but also of the sample pre-treatment, if necessary, and the measurement step. Furthermore, biosensor arrays offer additional advantages, such as the possibility to measure multiple samples and provide multi-mycotoxin profiles in one assay. In this case, apart from shortening the analysis time, accuracy is improved by the assessment of matrix interferences and synergistic effects among mycotoxins. Biosensors and arrays for mycotoxins are thus promising biotechnological tools for mycotoxin detection in food. Graphical Abstract        

Electrochemical production of novel products from 2,3-dimethylhydroquinone in the presence of some β-diketones

Abstract  Electrochemical oxidation of 2,3-dimethylhydroquinone has been studied in the presence of β-diketones as nucleophiles in aqueous solution using cyclic voltammetry and controlled-potential coulometry. The results indicate that the derivatives of 2,3-dimethylhydroquinone participate in a Michael addition reaction to form the corresponding benzofuran derivatives. The electrochemical synthesis has been successfully performed at pH 7.0 and E = 0.1 V versus an Ag|AgCl|KCl (3 M) in an undivided cell in good yield and purity. Graphical Abstract        

A synthesis of diethyl alkylsulfanylmethylmalonates catalyzed by KOH in an ionic liquid

Abstract  1-Ethyl-3-methylimidazolium bromide was used as a green recyclable alternative to volatile organic solvents for KOH catalyzed three-component synthesis of diethyl alkylsulfanylmethylmalonates from aldehydes, diethyl malonate, and alkylthiols. Graphical Abstract  A synthesis of diethyl alkylsulfanylmethylmalonates catalyzed by KOH in an ionic liquid      

Thermal ring opening of 1,1-dibromo and 1-bromo-2-chloromethylcyclopropanes: observation of a formal debromochlorination

Abstract  When the title compounds are thermolyzed in the gas phase under vacuum or in hot quinoline, several products are formed. A predominant product in all cases is a chlorine-free buta-1,3-diene which has been formed by formal debromochlorination, a reaction not previously observed during thermolysis of chlorinated bromocyclopropanes. Graphical Abstract        

Copper nitrate/acetic acid as an efficient synergistic catalytic system for the chemoselective tetrahydropyranylation of alcohols and phenols

Abstract  Tetrahydropyranylation of alcohols and phenols was accomplished successfully using copper nitrate and acetic acid as a synergistic catalyst at room temperature under solvent-free condition. Compared with other synergistic catalytic systems, copper nitrate/acetic acid proved to be the most efficient. Both alcohols (primary, secondary, tertiary, benzylic, cyclic, allyl, cinnamyl, and furyl) and phenols reacted smoothly in high yields. Graphical abstract        

Amino acid derivatives, X [1]: synthesis and antimicrobial evaluation of α-amino acid esters bearing a N1-protected tryptophan side chain

Abstract  A series of peptide derivatives conjugated with N¹-protected tryptophan residue was synthesized. The prepared compounds were tested for antimicrobial activity against four different bacterial species displaying different degrees of antibacterial activities or inhibitory actions. Graphical Abstract        

Efficient conversion of aldoximes to nitriles using phosphoric acid diethyl ester 2-phenylbenzimidazol-1-yl ester

Abstract  Aromatic aldoximes were converted to the corresponding nitriles in good to excellent yields by employing phosphoric acid diethyl ester 2-phenylbenzimidazol-1-yl ester as reagent. The method was equally effective for oximes bearing electron-donating and electron-withdrawing substituents. Graphical Abstract        

Synthesis of 3-(quinoxalin-2-yl)-2H-chromen-2-ones under microwave irradiation

Abstract  A facile procedure for the synthesis of quinoxalines is being reported starting from 3-(2-bromoacetyl)coumarins or 3-(2-bromobutanoyl)coumarins and substituted o-phenylenediamines. The reactions were carried out under catalyst-free and microwave irradiation conditions producing the title compounds in moderate to excellent yields in a short time with easy workup. The structures of all new compounds have been confirmed on the basis of their IR, ¹H NMR, ¹³C NMR, and HRMS data. Graphical Abstract        

Synthesis and pharmacological activity of some synthesized polyazacyclopenta[<Emphasis Type="Italic">a</Emphasis>]naphthalenes and pyrazolo[3,4-<Emphasis Type="Italic">b</Emphasis>]pyridines using 2-amino-6-methyl-4-phenylnicotinonitrile as synthon

Abstract  A series of pyridines, pyrimidines, and their derivatives were synthesized using 2-amino-6-methyl-4-phenylnicotinonitrile as starting material. Thirteen new heterocyclics containing a pyridine ring were thus prepared. Pharmacological screening showed that many of these compounds have good anti-inflammatory and analgesic activity comparable with those of diclofenac potassium and valdecoxib as reference drugs. Assignment of the structures of the new compounds was based on chemical and spectroscopic evidence. Synthesis, spectroscopic data, and pharmacological properties of the compounds are reported in detail. Graphical Abstract