Conformational polymorphism in a chiral spiro-cis-ansa-bridged cyclo­triphosphazene derivative

The reaction of spermidine with 2,2,4,4-tetra­chloro-6,6-di­phenyl­cyclo­triphosphazene produces a mixture of products of which one of the fractions is a spiro-cis-ansa deriv­ative, namely 12-chloro-14,14-di­phenyl-2,6,11,13,15,16-hexa­aza-1,12-di­phosphatri­cyclo­[10.3.1.0^1,6]­hexadeca-12,14-diene, C₁₉H₂₆Cl­N₆P₃. Recrystallization of this fraction from different solvents results in the formation of two different crystalline forms. The rod morphology formed in di­chloro­methane–n-hexane (1:1) produces a triclinic structure with three mol­ecules in the asymmetric unit. These three mol­ecules adopt different conformations as a result of two NH groups flipping in an ansa-bridged ring system. The plate morphology crystals, grown in di­chloro­methane–n-hexane–ethyl acetate (1:1:1), produce a C-centred monoclinic structure that adopts a conformation that is essentially the same as one of the forms in the triclinic structure.     

RAFT‐mediated synthesis and temperature‐induced responsive properties of poly(2‐(2‐methoxyethoxy)ethyl methacrylate) brushes

Well‐defined, high‐density poly(2‐(2‐methoxyethoxy)ethyl methacrylate) [poly(MEO₂MA)] brushes were fabricated through a reliable strategy by the combination of self‐assembly of a monolayer of 3‐aminopropyltrimethoxy silane on silicon surface to immobilize 4‐cyano‐4‐(dodecylsulfanylthiocarbonyl)sulfanyl pentanoic acid chain transfer agent and reversible addition‐fragmentation chain transfer‐mediated polymerization of MEO₂MA. The whole fabrication process of the poly(MEO₂MA) brushes was followed by water contact angle, grazing angle‐Fourier transform infrared spectroscopy, X‐ray photoelectron spectroscopy, and atomic force microscopy. Characterization of the poly(MEO₂MA) brushes, such as molecular weight and thickness determination, were measured by gel permeation chromatography and ellipsometry, and the grafting density was estimated. The temperature‐responsive property of the poly(MEO₂MA) brushes was further investigated and the result verified the brush‐to‐mushroom phase transition of the poly(MEO₂MA) chains from low to high temperature. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013     

Crosslinking of recycled polyethylene by gamma and electron beam irradiation

Recycling of polymeric materials is usually accompanied by degradation and deleterious properties. Irradiation crosslinking of recycling low density polyethylene by electron beam and gamma rays could be the solution to improve their properties. This paper presents a comparison on the effects of gamma and electron irradiation on virgin and recycled polyethylene. Their mechanical, thermal and chemical properties were analyzed. VPE samples shown higher crosslinking percentages than RPE samples in all range of doses studied, unirradiated RPE samples had higher values on their tensile properties than VPE. Percentage crystallinity was similar in all range of doses studied.     

On pairwise Lindelöf bitopological spaces

In this paper, we shall continue the study of bitopological separation axioms begun by Kelly and obtained some results. Furthermore, we introduce two concepts of pairwise Lindelöf bitopological spaces and the properties for them are established. We also show that a pairwise Lindelöf space is not hereditary property.     

N‐[Bis(2,4,6‐tri­methyl­phenoxy)­phos­phinoyl]‐P,P,P‐tris(2,4,6‐tri­methyl­phenoxy)phosphazene

The title compound, C₄₅H₅₅NO₆P₂, consists of an acyclic P=N—P(O) monophosphazene chain and five bulky 2,4,6‐tri­methyl­phenoxy side groups which predominantly determine the molecular shape. Although the P—N single [1.586 (3) Å] and P=N double [1.517 (3) Å] bonds are significantly different from each other, both are substantially shorter than the ideal P—N single bond. The P—N—P angle [146.0 (2)°] corresponds to the upper limit reported for acyclic phosphazene derivatives in the literature.     

Synthesis,characterization and photoluminescence studies of new Cu(II) complex

In the current work, a new coordination complex, [Cu(HL)₂], 1 [H₂L = 2–((E)–(2–hydroxypropylimino)methyl)–4–nitrophenol] was successfully synthesized and characterized by IR, UV-vis and photoluminescence spectroscopic techniques, single crystal and powder X-ray diffraction measurements. In the crystalline structure of complex 1, the aliphatic –OH group of the ligand is not coordinated and points away from the metal coordination zone, and also actively participates in intermolecular bifurcated O?H···O hydrogen bonds which link the molecules to form hydrogen-bonded linear chains. C?H···π and π···π contacts also connect the molecules in the structure which form to 3D structure. This hydrogen bonded polymeric networks lie in the bc-plane and stacks along to the a-axis. Furthermore, complex 1 and its ligand H₂L display an intense navy-blue emission and blue emission in the solid state at room temperature, respectively, when they are excited under UV light.     

A multiple exp-function method for the three model equations of shallow water waves

Nonlinear Dynamics - In this study, we consider three model equations of shallow water waves. Shallow water equations model the propagation of strongly nonlinear waves up to breaking and run-up in...     

A Green Protocol for Simple One‐pot Synthesis of New Pyrimidine Derivatives Both Microwave Irradiation and Conventional Heating: Reactions,Characterization, and Theoretical Calculations

In this research, 5‐benzoyl‐6‐phenyl‐4‐(4‐trifluoromethylphenyl)‐2‐{oxo and thioxo}‐3,4‐dihydro‐1H‐pyrimidines ( 1 , 2 ) were synthesized by using multicomponent cyclocondensation reaction under microwave irradiation and classical heating. Compounds 3 , 4 , 6 , 7 , and 8 obtained reactions of 5‐benzoyl‐6‐phenyl‐4‐(4‐trifluoromethylphenyl)‐2‐thioxo‐3,4‐dihydro‐1H‐pyrimidine ( 1 ) and acetic anhydride, diethyl 2‐bromomalonate, bromoacetic acid, 3‐bromopropionic acid, methyl iodide, respectively. Compound 4 was both acetylated and hydrolyzed in acetic acid to give compound 5 . The structures of all compounds were determined by using spectroscopic techniques like FT‐IR, ¹H/¹³C NMR, and elemental analyses, and the structures of compounds 1 and 3 were analyzed by X‐ray crystal analysis. In addition, the quantum chemical parameters and full geometry optimizations for all compounds were computed using density functional theory based on B3LYP and the 6‐31G (d, p) basis set.     

A conventional and solid-state synthesis,biological activity,and molecular docking studies of 6-arylbenzo[4,5]imidazo[1,2-a] [1,8]naphthyridin-10-ols

An effective, practical, and simple approach toward the preparation of highly-substituted 6-arylbenzo[4, 5]imidazo[1,2-a][1,8]naphthyridin-10-ols 6(a-h) by the reaction of 3-aryl-1,8-naphthyridin-2-amines 3(a-h) with benzoquinone 4 in acid catalyzed cyclization under solid-state method, as well as conventional conditions, has been described. The products are obtained in good yields and in a solid of high purity. The major advantages of solid states are easy workup, low costs, short reaction time, good efficacy, and environment-friendly procedure. The newly synthesized compounds were thoroughly characterized using spectral data and elemental analyses. All compounds were screened for their biological evaluation. Predominantly 6b and 6c compounds showed the highest antibacterial activity. Moreover, all the synthesized compounds were docked against topoisomerase II DNA gyrase enzyme.