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      Volume 131, Issue 6

      June 2019

    • Table of Contents

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    • Elucidation of the oxidation-reduction reactions in the synthesis of Co-based nanoparticles through polyol process using 1, 2-butanediol (BEG): a theoretical study

      KHOULOUD MRAD NOURA KHEMIRI FRÉDÉRIC SCHOENSTEIN SILVANA MERCONE MHAMED BEN MESSAOUDA MANEF ABDERRABBA SABRI MESSAOUDI

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      The role of BEG 1,2-butanediol as a reducing agent in Co-based nanoparticle synthesis in the polyol process has not been well-detailed yet. So, we focused on the determination of the main active species derived from 1,2-butanediol (BEG) in Co-based nanoparticle synthesis and their reducing abilities through density functional theory (DFT) calculations. In the reaction medium, BEG is deprotonated by the hydroxyl ions introduced in the solution then oxidized by the metal ions. The progression of reduction and dissociation reactions of metal ions is relatively related to the reducing ability of polyols. Three species which are: dianion, monoanion and neutral molecule of BEG were considered in our investigation. The highest occupied orbital energy was estimated for the different configurations. Considering the experimental and theoretical studies, themonoanion state was suggested as the most active form. A comparative study was carried out between three polyols: BEG, PEG (1, 2-propanediol) and EG (Ethylen glycol), which are the most used solvents in Co-based nanoparticle synthesis.We showed that the highest occupied orbital energy of BEG monoanion state is relatively high compared to PEG and EG ones. Thus, BEG could reduce metal ions more easily by giving its electrons and its use can make the reaction kinetics faster

    • Design, synthesis, and molecular docking of new 5-HT reuptake inhibitors based on modified 1,2-dihydrocyclopenta[b] indol-3(4H)-one scaffold

      MILENA SZEWCZYK PAWEŁ PUNDA KAROLINA JANIKOWSKA SłAWOMIR MAKOWIEC

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      A new group of serotonin reuptake inhibitors containing 1,2-dihydrocyclopenta[b]indol-3(4H)-one scaffoldwas synthesized, starting from indole 5-((1H-indol-3-yl)(1,3-dioxane-4,6-diones as a key intermediates.Following three transformations including intramolecular cyclization and formation of imines, a series of new ligand for human serotonin transporter was obtained. The ability of these ligands to inhibit human TS3 serotonin transporter as well as selectivity toward human D3 dopamine receptor and dopamine transporter were tested in silico using docking software.

    • Potassium iodate (KIO3) as a novel reagent for the synthesis of isoxazolines: evaluation of antimicrobial activity of the products

      SUMANA Y KOTIAN P M ABISHAD K BYRAPPA K M LOKANATHA RAI

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      A novel reagent for the synthesis of isoxazolines has been reported. Aryl aldoximes were made to react with alkenes in the presence of KIO3 as the oxidising agent. This new reagent has been useful as an oxidant in the synthesis of isoxazoline and its function is attributed to the generation of nitrile oxide, which is an important intermediate for the synthesis of the valuable heterocycle like isoxazoline

    • New self-assembled archetypes in crown ether substituted ∆ZPhe containing tripeptides

      KALPANA TOMAR GURUNATH RAMANATHAN

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      We examine the effect of crown ether ring sizes on structure and properties of three terminally protected tripeptides containing substituted dehydrophenylalanine residues; Bz-∆Phe(12-crown-4)-Phe-Phe-OMe, Bz-∆Phe(15-crown-5)-Phe-Phe-OMe, Bz-∆Phe(18-crown-6)-Phe-Phe-OMe. The resultant self-assembly of the peptides generates nano-vesicles, which further alter into the necklace type of structures that were characterized via their SEM, LRTEM, and AFM images.We also report the disruption of these vesicles in the presence of different metal ions.

    • A simple, fast and excellent protocol for the synthesis of phenols using CuFe2O4 magnetic nanoparticles

      RITUPARNA CHUTIA BOLIN CHETIA

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      This paper describes a very mild, quick and simple protocol for the synthesis of phenols using CuFe2O4 magnetic nanoparticles as a catalyst. The nanosized catalyst has an average diameter of 17.63 nm. The magnetic nanoparticles were characterized by SEM, EDX, VSM, XRD and TEM analysis. The synthesisof phenols from phenylboronic acids using H2O2 as an oxidant proceeded very well with excellent yields. Heterogeneous catalyst, easy recyclability, mild reaction conditions, short reaction time added as an advantage for the present protocol.

    • A high-performance gel polymer electrolyte based on poly(vinylidene fluoride)/thermoplastic polyurethane/poly(propylene carbonate) for lithium-ion batteries

      JIANGLAN XU YUEWEN LIU QI CAO BO JING XIANYOU WANG LI TAN

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      Fibrous membranes of composites of poly(vinylidene fluoride (PVDF)/thermoplastic polyurethane (TPU)/poly(propylene carbonate) (PPC) are prepared with different concentrations by electrospinning method. The physical properties of the films are characterized, such as morphology, porosity, thermal stability and mechanical properties. After electrospun films with different concentrations are activated to gel polymer electrolyte (GPE), we test their electrochemical properties. The morphology and the thermal stability of thePVDF/TPU/PPC nanofibers (NFs) with a concentration of 12% are the best. It shows the high tensile strength of 9.9MPa and the maximum elongation of 110.8%. The ionic conductivity of its corresponding GPE is as highas 5.32 mS cm−1, and the electrochemical stability window is up to 5.4 V at room temperature. In addition, it shows a high initial charge capacity of 165.8mAh g−1 and a high initial discharge capacity of 165.1 mAh g−1. The excellent properties make the PVDF/TPU/PPC based GPE (12%) more suitable for lithium-ion batteries

    • Tuning the adsorption properties of UiO-66 via acetic acid modulation

      NAIWANG LIU LI SHI XUAN MENG

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      UiO-66 (Universitetet i Oslo) is one of the most known metal-organic frameworks with high hydrothermal stability. In this work, a series of UiO-66 were prepared using acetic acid as a modulator to produce linker defects. Samples were characterized by X-ray powder diffraction, nitrogen adsorption-desorptionisotherms, thermogravimetric analysis and adsorptive desulfurization test. Results indicated that increasing the amount of acetic acid to 30% equivalent with respect to terephthalic acid did not have an obvious negative effect on the structure. At the same time, surface area and micropore pore volume are further increased from 988 m2/g, 0.34 cm3/g to 1424 m2/g, 0.54 cm3/g. Adsorptive desulfurization performance is also significantly improved from 6.0 mg/g to 7.9 mg/g. So, the linker defects produced by acetic acid can remarkably enhance the adsorptionability. Adsorptive desulfurization kinetics indicates that while indicating the monomolecular layer, chemical adsorption occupies the dominant position, and there is no special chemical force formed between the defects and dibenzothiophene

    • Active bismuth mediated allylation of carbonyls/N-tosyl aldimines and propargylation of aldehydes in water

      MICKY LANSTER SAWKMIE DIPANKAR PAUL SNEHADRINARAYAN KHATUA PARESH NATH CHATTERJEE

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      Active bismuth is synthesized by the chemical reduction of bismuth trichloride using freshly prepared sodium stannite solution as the reducing agent at room temperature. The as-synthesized active bismuth is applied as a reagent for the synthesis of homoallyl alcohol/homopropargyl alcohol from allyl bromide/propargyl bromide and carbonyl compounds in water at 50◦C. The homoallyl amines are also synthesized from N-tosyl aldimines and allyl bromide using active bismuth reagent in good yields. No assistance of organic co-solvent, co-reagent, phase transfer catalyst or inert atmosphere is required for this reaction. The waste bismuth material obtained after the completion of the organic reaction can be reduced to active bismuth by sodium stannite solution andsuccessfully reused for mediating the allylation of aldehydes.

    • Dimeric conformation sensitive electronic excited states of tetracene congeners and their unconventional non-fluorescent behaviour

      N AGGARWAL A PATNAIK

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      Unconventional non-fluorescent J-aggregates of Tetracene (TC) and Naphtho[2,1,8-qra]tetracene (NT) were witnessed and their consequent dramatic quenching was unravelled by a steady state, time-resolved and transient spectroscopy in conjunctionwith excited state density functional calculations. The TC O-aggregate with slippage angle θ = 22.3◦ ˂ 54.7◦ exhibited substantial transition dipole moment (TDM) for both lower (2.79 D) and higher (1.59 D) energy singlet excitations, while, NT formed an ideal J-aggregate (polarizationangle, α ~ 0◦ ) with a predominant TDM to only a lower excitonic state (2.69 D). Subsequently, their unusual quenching was quantified with large drops in the photoluminescence quantum yields (PLQY) from 0.116 to 0.002 upon TC O-aggregation and from 0.478 to 0.038 upon NT J-aggregation. These intense PL drops were systematically investigated for possible occurrence of excimer-like emission quenching and/or photodegradation of the TC core unit. In view of the TC O-aggregates exhibiting a perfect energetic balance between the singlet (2.34 eV) and triplet (1.28 eV) energies for singlet fission (SF) and a concomitant delayed fluorescence signal, their S1 decay characteristics were attributed to SF followed by an inverse triplet-triplet recombination.In contrast, the energetic imbalance (E(S1) ˂ 2xE(T1)) in NT J-aggregates permitted only forward processof SF and the resulting long-lived triplet formation was traced with a positive transient absorption (T1 → Tn) band at 500 nm. Accordingly, the singlet excited state (S1) dynamics of TC O- and NT J-aggregates, being largely dominated by SF, depicted a depleted S1 population, accounting for the large deviation from aggregation induced enhanced emission, exhibited by classical dye J-aggregates.

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