Nuclephilic ring opening of epoxides promoted by multi-site phase-transfer catalyst:An efficient and eco-friendly route to synthesis of b-hydroxy-thiocyanate

A highly effective and mild protocol for ring opening of epoxides with NH ₄ SCN in the presence of catalytic amount of a multisite phase-transfer catalyst, α,α',α" -N-hexakis(triethylammoniummethylene chloride)-melamine, is developed. A variety of b-hydroxy thiocyanates as important intermediates in agricultural and pharmaceutical chemistry were obtained in high yields with excellent regioselectivity and in short reaction times.     

Mechanical properties of diboron-porphyrin sheet under strain: A density functional theory study

The mechanical properties of a new two-dimensional semiconductor material named diboron-porphyrin (DP) are studied based on density functional theory. The behavior of DP monolayer under uniaxial and biaxial loadings as well as shear stress is investigated. The in-plane stiffness, Poisson's ratio, bulk and shear moduli of the DP monolayer are found to be close to those of a graphene sheet. It can be concluded that the DP monolayer has stiffness close to the graphene sheet. The difference in magnitude of in-plane stiffness and Poisson's ratio along x- and y-directions shows slightly anisotropic mechanical properties of DP monolayer. It is also observed that DP monolayers can bear high tensile strains before failure. The high stability and hardly deformable structure of DP monolayer are due to its high planar packing density which is comparable with graphene sheet. The fantastic mechanical properties of DP show these materials are desirable for application in nanomechanical devices.     

ZnS nanoparticles incorporated in polyaniline composite: Preparation and optical characterization

Hybrid polyaniline based composites incorporating zinc sulfide nanoparticles have been synthesized by using chemical oxidation technique. Morphological and optical properties of the nanocomposite were characterized by scanning electron microscopy, Fourier transform infrared and UV–Vis spectroscopy measurement. The results were compared with pure polyaniline. The characteristic FTIR peaks of polyaniline were found to shift to lower wave-number in nanocomposite. The band gap of nanocomposites increases and the refractive index of the nanocomposites decreases with increasing content of ZnS nanoparticles. These results showed the interaction between ZnS nanoparticles and polyaniline.     

Sulfonated Honeycomb Coral (HC-SO<Subscript>3</Subscript>H): a new,green and highly efficient heterogeneous catalyst for the rapid one-pot pseudo-five component synthesis of 4,4′-(aryl methylene) bis(3-methyl-1<Emphasis Type="Italic">H</Emphasis>-pyrazol-5-ol)s

Sulfonated Honeycomb Coral (HC-SO₃H), has been synthesized from the reaction of Honeycomb Coral with chlorosulfonic acid as sulfonating agent. The as-synthesized catalyst was characterized via XRF, FT-IR, TGA, SEM–EDS, XRD, BET and pH analysis. The superior catalytic activity of HC-SO₃H was investigated for the synthesis of 4,4′-(aryl methylene)bis(3-methyl-1H-pyrazol-5-ol) derivatives through the one-pot pseudo-five component reactions. The main advantages of this protocol include simple procedure, excellent yields and short reaction times besides the non-toxicity, high stability and reusability of the catalyst.     

The first urea‐based ionic liquid‐stabilized magnetic nanoparticles: an efficient catalyst for the synthesis of bis(indolyl)methanes and pyrano[2,3‐d]pyrimidinone derivatives

Urea‐based ionic liquid stabilized on silica‐coated Fe₃O₄ magnetic nanoparticles, {Fe₃O₄@SiO₂@(CH₂)₃‐Urea‐SO₃H/HCl}, as an unexceptionable and smooth releasing urea fertilizer in alkali soils was synthesized and fully characterized using Fourier transform infrared, UV–visible and energy‐dispersive X‐ray spectroscopies, X‐ray diffraction, scanning and transmission electron microscopies, atomic force microscopy and thermogravimetric analysis. The nanostructure catalyst as a novel, green and efficient catalyst was applied for the synthesis of bis(indolyl)methane derivatives via the condensation reaction between 2‐methylindole and aldehydes at room temperature under solvent‐free conditions. Also, pyrano[2,3‐d]pyrimidinone derivatives were prepared in the presence of the nanomagnetic urea‐based catalyst by the one‐pot three‐component condensation reaction of 1,3‐dimethylbarbituric acid, aldehydes and malononitrile under solvent‐free conditions at 60 °C. To the best of our knowledge, this is the first report of the synthesis of urea‐based ionic liquid stabilized on silica‐coated Fe₃O₄ magnetic nanoparticles. So the present work can open up a new and promising insight in the course of rational design, synthesis and applications of task‐specific fertilizer‐based nanomagnetic ionic liquids with desirable properties as unexceptionable substances for sustainable processes. Copyright © 2016 John Wiley & Sons, Ltd.     

Synthesis of the first nanomagnetic particles with semicarbazide‐based acidic ionic liquid tag: an efficient catalyst for the synthesis of 3,3′‐(arylmethylene)bis(4‐hydroxycoumarin) and 1‐carbamato‐alkyl‐2‐naphthol derivatives under mild and green conditions

Semicarbazide functionalized with chlorosulfonic acid on the surface of silica‐coated magnetic nanoparticles, {Fe₃O₄@SiO₂@(CH₂)₃Semicarbazide‐SO₃H/HCl}, as a novel magnetic Brønsted acid catalyst according to the aims of green chemistry was synthesized and fully characterized using Fourier transform infrared, UV–visible and energy‐dispersive X‐ray spectroscopies, X‐ray diffraction, scanning electron, transmission electron and atomic force microscopies and thermogravimetric analysis. The capability and excellent activity of this nanoparticle catalyst were exhibited in the synthesis of two series of compounds with important biological activities, namely 3,3′‐(arylmethylene)bis(4‐hydroxycoumarin) and 1‐carbamato‐alkyl‐2‐naphthol derivatives, under mild, green and solvent‐free conditions. To the best of our knowledge, this is the first study of the synthesis and application of {Fe₃O₄@SiO₂@(CH₂)₃Semicarbazide‐SO₃H/HCl} as Brønsted acid solid magnetic nanoparticles. Consequently the present study can open up a novel and promising intuition in the sequence of logical design, synthesis and applications of task‐specific Brønsted acid magnetic nanoparticle catalyst with favourable properties as a full‐fledged efficient material for sustainable approaches. Copyright © 2016 John Wiley & Sons, Ltd.     

Border collision and fold bifurcations in a family of one-dimensional discontinuous piecewise smooth maps: divergence and bounded dynamics

In this work we continue the study of a family of 1D piecewise smooth maps, defined by a linear function and a power function with negative exponent, proposed in engineering studies. The range in which a point on the right side is necessarily mapped to the left side, and chaotic sets can only be unbounded, has been already considered. In this work we are characterizing the remaining ranges, in which more iterations of the right branch are allowed and in which divergent trajectories occur. We prove that in some regions a bounded chaotic repellor always exists, which may be the only non-divergent set, or it may coexist with an attracting cycle. In another range, in which divergence cannot occur, we prove that unbounded chaotic sets always exist. The role of particular codimension-two points is evidenced, associated with fold bifurcations and border collision bifurcations (BCBs), related to cycles having the same symbolic sequences. We prove that they exist related to the border collision of any admissible cycle. We show that each BCB, each fold bifurcation and each homoclinic bifurcation is a limit set of infinite families of other BCBs.     

Binuclear and polymeric Hg(II) complexes of an ambidentate phosphorus ylide: Synthesis,crystal structure,antibacterial activity,and theoretical studies

The new α-keto-stabilized phosphorus ylide Ph₃PCHC(O)PhCN ( Y ) was synthesized by addition of triphenylphosphine to 2-bromo-4′-cyanoacetophenone, followed by treatment with NaOH 10%. Reaction of ligand ( Y ) with methanolic solution of mercury(II) halides under mild conditions yielded the binuclear complexes [Y·HgX₂]₂ [X=Cl ( 1 ), Br ( 2 ), I ( 3 )]. The new organic/inorganic composite polymer [Hg(NO₃)₂(Y)]_n ( 4 ) was synthesized by the reaction of mercury(II) nitrate with the phosphorus ylide Y . Compounds synthesized were characterized by Fourier-transform infrared, ¹H, ³¹P, and ¹³C nuclear magnetic resonance spectroscopic methods, which confirmed the coordination of ylide to the metal center through the ylidic carbon atom. Single-crystal X-ray structures of phosphorus ylide Y and polymeric complex 4 were also determined and the crystallographic data of complex 4 showed that the title complex has an infinite one-dimensional structure. Furthermore, the electronic and molecular structures of complexes 1 – 3 were investigated at the BP86/def2-SVP level of theory, indicating an increasing trend for C→M bond lengths: Hg₂I₂ > Hg₂Br₂ > Hg₂Cl₂ in [Y→HgX₂]₂ (X = Cl, Br, I) complexes. In addition, the antibacterial activity of ligand Y and all complexes using the agar disc diffusion method was examined against both selected gram-positive and gram-negative bacteria. Results indicated that the ligand Y and complexes 1 and 4 show good antibacterial effect against gram-positive bacteria tested; besides, the inhibition zones of complexes were significantly larger than those of chloramphenicol as standard.     

Investigation of viscoelastic and thermal properties of cyclic carbonate bearing copolymers

In this paper, one-pot reaction of radical copolymerization of glycidyl methacrylate with methyl methacrylate, n-butyl acrylate and styrene under carbon dioxide atmosphere (1 atm) was employed to synthesize cyclic carbonate bearing copolymers. Obtained copolymers were characterized using ¹H NMR and FTIR spectroscopy. The viscoelastic and thermal properties of the resulted copolymers were investigated using dynamic mechanical thermal analysis and thermogravimetric analysis. Copolymer composition and monomer type had a significant effect on the properties of the copolymers. An increase in cyclic carbonate (2-oxo-1,3-dioxolane-4-yl-methyl methacrylate) content in the copolymer composition led to an increase in glass transition temperature, storage modulus and loss tangent as well as the thermal stability of the copolymers.