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      Volume 129, Issue 4

      April 2017,   pages  414a-513

    • Table of Contents

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    • Sulfated polyborate: A mild, efficient catalyst for synthesis of N-tertbutyl/N-trityl protected amides via Ritter reaction

      KRISHNA S INDALKAR CHETAN K KHATRI GANESH U CHATURBHUJ

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      Rapid, efficient and inexpensive method for synthesis of N-tert-butyl/N-trityl protected amides via Ritter reaction of nitriles with tertiary alcohols in the presence of a sulfated polyborate catalyst under solvent-free conditions is described. The catalyst has the advantage of Lewis as well as Bronsted acidity and recyclability without significant loss in catalytic activity along with easy work-up, short reaction time and good to excellent yields.

    • Cerium(IV) carboxymethylcellulose (CMC−CeIV) as an efficient and reusable catalyst for the one-pot pseudo-four component synthesis of 2,4,6-triphenylpyridines

      YANG CHEN TIANZHU ZHANG DONGYANG WANG JUNBIN ZHOU YIZONG ZHANG YIQUN LI

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      Cerium(IV) carboxymethylcellulose (CMC−CeIV) was found to be a highly efficient, eco-friendly and recyclable heterogeneous catalyst for the synthesis of 2,4,6-triarylpyridine derivatives in excellent yields via one-pot multicomponent reaction of various benzaldehydes, acetophenones, and ammonium acetate under solvent-free condition. Moreover, the present protocol has the merits of easy work-up, short reaction times, and high yields.

    • Copper(II) complex as a precursor for formation of cyano-bridged pentanuclear FeIII-CuII bimetallic assembly: Synthesis, characterization, crystal structure and antibacterial activity

      SURACHAI KONGCHOO KITTIPONG CHAINOK ANOB KANTACHA SUMPUN WONGNAWA

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      [CuL(ClO ₄) ₂] (1) (L = 3,10-diisobutyl-1,3,5,8,10,12-hexaazacyclotetradecane) was synthesized by condensation reaction of ethylenediamine, formaldehyde and iso-butylamine in absolute ethanol. Characterization of 1 utilized various spectroscopic techniques, viz. elemental analysis, electrospray ionization-mass spectrometry (ESI-MS), Fourier-transform infrared spectroscopy (FT-IR), ultraviolet-visible spectroscopy (UV-Vis), diffuse reflectance spectroscopy (DRS) and thermogravimetric analysis (TGA). Based on these techniques, the structure of 1 was proposed as Cu(II) ion occupying octahedral geometry with four secondary amine nitrogens of the hexaazamacrocyclic ligand and two perchlorato anions. 1 was used as a precursor in the preparation of cyano-bridged bimetallic compound, [CuL] ₃ [Fe(CN) ₆] ₂•5H ₂O (2), by reaction with K ₃ [Fe(CN) ₆] in aqueous solution. Single-crystal X-ray analysis indicated that 2 crystallized in the monoclinic system with space group P21/n. The structure of 2 consisted of cyano-bridged FeIII-CuII pentanuclear molecules having two [Fe(CN) ₆] ³⁻ anions connected to three cis-[CuL] ²⁺ cations via two cis-cyanide ligands from each ferrate unit. In each of pentanuclear unit, the central [CuL] ²⁺ cation exhibited a distorted octahedral geometry while the other two units exhibited a distorted square pyramidal geometry. The room temperature magnetic moments of both complexes were measured to be 1.92 B.M. for 1 and 5.61 B.M. for 2. The in vitro antibacterial activity of 1 against Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, and Pseudomonas aeruginosa ATCC 27853 strains were studied and compared with standard drugs, which showed moderate antibacterial activity compared with Penicillin and Gentamicin.

    • Synthesis, thermal properties and photoisomerization of trans-[Ru(NO)Py₂Cl₂(H₂O)]H₂PO₄·H₂O

      ALEXANDER N MAKHINYA ILYA V KOROLKOV MAXIM A IL’IN IRAIDA A BAIDINA PAVEL E PLUSNIN EUGENI A MAXIMOVSKI ELIZAVETA A BELETSKAYA NINA I ALFEROVA

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      The reaction of trans-[Ru(NO)Py₂Cl₂ (OH)] with concentrated o-phosphoric acid, after washing the mixture with diethyl ether, gave trans-[Ru(NO)Py₂Cl₂(H₂O)]H₂PO₄•2H₃PO₄•H₂O (I) in nearly quantitative yield. The structure of this compound was determined by X-ray diffraction analysis: space group P-1. Washing of I with ethanol afforded the dihydrophosphate salt trans-[Ru(NO)Py₂Cl₂ (H₂O)]H₂PO₄•H₂O (II) (yield 97%). The thermal decomposition of I and II in a helium atmosphere resulted in the formation of ruthenium phosphide RuP as a predominant component along with Ru₂P or RuP₂. Preliminary photoisomerization experiments for trans-[Ru(NO)Py₂Cl₂ (OH)] and trans-[Ru(NO)Py₂Cl₂ (H₂O)]H₂PO₄•H₂O suggested the presenceof metastable states. DSC experiments have been carried out for both compounds. The measured kinetic parameters for the metastable decay for trans-[Ru(NO)Py₂Cl₂ (H₂O)]H₂PO₄•H₂Owere Ea = 90.7± 2.4 kJ/mol, log10(k0/sec−1) = 18.9±0.6, and Td = 217 K.

    • Magnesium Trimethoxyphenylporphyrin Chain Controls Energy Dissipation in the presence of Cholesterol

      KARISHMA DEVI BORAH N GHANASHYAM SINGH JAGANNATH BHUYAN

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      A magnesium porphyrin compound, [Mg(TMPP)(H ₂O)].(CH ₃COCH ₃)2H ₂O 1 (TMPP = 5,10,15,20-tetrakis(3,4,5-trimethoxyphenyl)porphyrin) has been synthesized and characterized using single crystal X-ray diffraction and other spectroscopic analysis. The luminescence properties of compound 1 were studied at different concentrations. At higher concentration (3×10 ⁻³ M), treatment of 1 with cholesterol enhanced the luminescence when excited at Soret band, demonstrating the role of lipid in controlling porphyrin-porphyrin interaction for tuning the bulk photophysical properties. However, at lower concentration (10 ⁻⁵ M) of porphyrin, there was no significant change in luminescence intensity in the presence of cholesterol. It suggests some role of lipids in light harvesting systems where chlorophyll is present at higher concentration.

    • Preparation and application of a magnetic organic-inorganic hybrid nanocatalyst for the synthesis of α-aminonitriles

      ALI MALEKI RAZIEH FIROUZI HAJI MINA GHASSEMI HOSSEIN GHAFURI

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      This article is the first report of the catalytic application of copper ferrite-coated chitosan in organic reactions as a bio-nanocomposite. CuFe2O4/chitosan was used as a hybrid nanocatalyst for the multicomponent Strecker synthesis of α-aminonitriles by using aryl aldehydes, trimethylsilyl cyanide (TMSCN) and aromatic amines at room temperature in ethanol as a green solvent. The catalyst was characterized by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), field-emission scanning electron microscopy (FE-SEM) and energy-dispersive X-ray spectroscopy (EDX) analyses. The nanocatalyst was recovered and reused several times without significant loss of catalytic activity. The organic products were obtained easily without need for column chromatography in good-to-excellent yields.

    • A simple hydrazine based molecule for selective detection of Fluoride ion in DMSO

      ADDITI ROY CHOWDHURY PRIYABRATA BANERJEE

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      A newly synthesized hydrazine-functionalized Schiff base chemoreceptor [N¹N³−bis(4-cyanobenzylidene) isophthalahydrazide], NBCBIH has been prepared and successfully utilized for selective detection of Fluoride ion. Herein, NH and C=N-like functional units have been incorporated which providebetter colorimetric response compared to systems where such kind of units are absent. On exposure to F⁻, NBCBIH turns from almost colorless to yellow. The recognition is well-supported by UV-Vis, fluorescence and ¹H-NMR in DMSO. The fluorescence quenching is well-explained by photoinduced electron transfer mechanism (PET). The limit of detection of F− with NBCBIH is 0.7 × 10⁻⁴M.

    • Hydrazone derivatives appended to diphenylphosphine oxide as anion sensors

      MARUTHAI KUMARAVEL JOEL T MAGUE MARAVANJI S BALAKRISHNA

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      Phosphine substituted hydrazones with or without nitro substituents were synthesized and characterized by multinuclear NMR, FT-IR, UV-Vis spectroscopy and single crystal X-ray diffraction. The anion recognition properties of phosphine oxides {Ph₂P(O)C₆H₄CHNNHPh} (2) and {Ph₂P(O)C₆H₄CHNNHC₆H₃ (2,4-NO₂) ₂} (4) with anions (F⁻, Cl⁻, Br⁻, I⁻, CH₃COO⁻ and H₂PO⁻ ₄ ) were investigated. The selectivity towards these anions is attributed to the hydrogen bonding capability of the NH bond. Competitive titrations have shown that the binding ability of fluoride with 4 is not influenced by the presence of other anions.

    • Synthesis, Spectral, Electrochemical and Theoretical Investigation of indolo[2,3-b]quinoxaline dyes derived from Anthraquinone for n–type materials

      BHARAT K SHARMA AZAM M SHAIKH SAJEEV CHACKO RAJESH M KAMBLE

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      Aseries of five novel dyes based on indolo[2,3-b]quinoxaline skeleton, derived from anthraquinone, have been synthesized through cyclo-condensation reaction in good yield. The photophysical, electrochemical and thermal properties along with computed HOMO-LUMO energy levels were studied for the synthesizedcompounds. Their absorption and photoluminescence properties were investigated in various solvents and in neat solid film and found to possess characteristic electronic absorption and emission spectra which stronglydepend on the nature of solvents used. Compounds show intramolecular charge transfer transitions (ICT) in the range of 501–561 nm with high molar absorption coefficient (ε). These indoloquinoxaline derivatives emit in the range of 580–648 nm in solutions and 672–700 nm (red region) in neat solid films. Electrochemical data indicate that the dyes possess relatively low–lying LUMO levels in the range −3.29 to −3.43 eV. The thermal stability observed for these compounds suggests their use under ambient conditions. The in–built donor– acceptor architecture and HOMO–LUMO energies were further rationalized using DFT calculations. This study suggests that these compounds have potential to be used as n–type materials for optoelectronic devices.

    • Crystal structure and morphology of β-HMX in acetone: A molecular dynamics simulation and experimental study

      JUN TAO XIAOFENG WANG

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      Single crystals of β-Cyclotetramethylene tetranitramine (HMX) were prepared by the solvent evaporation method. The structure was then determined using infrared spectroscopy and single crystal X-ray diffraction. The modified attachment energy (AE) model was used to predict the morphologies of β-HMXin vacuum and in acetone. The morphology and sensitivity of HMX before and after recrystallization were characterized. The results of calculation showed that the (011) and (110) surfaces of β-HMX are of great morphologicalimportance. The predicted β-HMX morphology agreed qualitatively with the SEM result. The sensitivity results show that recrystallization in acetone can effectively reduce the impact and friction sensitivities of β-HMX.

    • DFT study on the mechanism of InBr3-catalyzed [2+2] cycloaddition of allyltrimethylsilane with alkynones

      XING HUI ZHANG

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      Density functional theory calculations at the M06-2X level were done to study the reaction mechanism and regioselectivity for the [2+2] cycloaddition of allyltrimethylsilane with alkynones using InBr₃ as the catalyst. The solvent effect was described by the single-point calculations with SMD model in 1,2-dichloroethane. The calculation results prove that the InBr₃-catalyzed cycloaddition of allyltrimethylsilane to alkynones takes place through two possible pathways and get selective cyclobutenone products. The reaction involves two main steps: attack of unsaturated carbon atoms of the alkynone by the π electrons of allyltrimethylsilane and a closed-loop process. The process of forming cyclobutenone product of silicon in the 2-position of the ketone group is more favored and the barrier is 15.5 kcal/mol, while the energies for the cyclobutenone of 3-position product are relatively high of 21.2 kcal/mol. In addition, we calculated the catalytic activity of the InX₃(X=Cl, Br, I) catalyst for this cycloaddition. This is a good explanation for the experimental data thatInBr₃ and InI₃ would be the most effective catalysts.

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