Synthesis and characterization of novel substituted and cyclic benzoquinone derivatives

Novel substituted benzoquinone compounds were synthesized from the reactions of p-chloranil and p-fluoranil with some thiols, amines, and diols in different reaction media. Interesting cyclic compounds like crown ether structures were obtained. The structures of all compounds were characterized by spectroscopic methods and microanalysis.     

XPS characterization of Au (Core)/SiO2 (shell) nanoparticles

Core-shell nanoparticles with ca. 15-nm gold core and 6-nm silica shell were prepared and characterized by XPS. The Au/Si atomic ratio determined by XPS is independent of the electron takeoff angle because of the concentric spherical shape of the nanoparticles. The formula given by Wertheim and DiCenzo (Phys. Rev. B 1988, 37, 844) for spherical nanoparticles and the modified one by Yang et. al. (J. Appl. Phys. 2005, 97, 024303) for core-shell nanoparticles are used to correlate the XPS-derived composition with the geometry of the nanoparticles only after significantly modifying either the bulk density of the silica shell or the attenuation length of the photoelectrons.     

Stability to vector Liénard equation with constant deviating argument

In this paper, we consider the vector Liénard equation with the constant deviating argument, τ>0, $$X''(t) + F\bigl(X(t),X'(t) \bigr)X'(t) + H\bigl(X(t - \tau)\bigr) = P(t) $$ in two cases: (i) P(.)≡0, (ii) P(.)≠0. Based on the Lyapunov–Krasovskii functional approach, the asymptotic stability of the zero solution and the boundedness of all solutions are discussed for these cases. We give an example to illustrate the theoretical analysis made in this work and to show the effectiveness of the method utilized here.     

一类三阶向量微分方程解的有界性和周期性

对某一类三阶向量微分方程周期解的存在性和解的毕竟有界性给出了充分条件。     

Neuroactive Peptide Nanofibers for Regeneration of Spinal Cord after Injury

The highly complex nature of spinal cord injuries (SCIs) requires design of novel biomaterials that can stimulate cellular regeneration and functional recovery. Promising SCI treatments use biomaterial scaffolds, which provide bioactive cues to the cells in order to trigger neural regeneration in the spinal cord. In this work, the use of peptide nanofibers is demonstrated, presenting protein binding and cellular adhesion epitopes in a rat model of SCI. The self‐assembling peptide molecules are designed to form nanofibers, which display heparan sulfate mimetic and laminin mimetic epitopes to the cells in the spinal cord. These neuroactive nanofibers are found to support adhesion and viability of dorsal root ganglion neurons as well as neurite outgrowth in vitro and enhance tissue integrity after 6 weeks of injury in vivo. Treatment with the peptide nanofiber scaffolds also show significant behavioral improvement. These results demonstrate that it is possible to facilitate regeneration especially in the white matter of the spinal cord, which is usually damaged during the accidents using bioactive 3D nanostructures displaying high densities of laminin and heparan sulfate‐mimetic epitopes on their surfaces.     

ON STABILITY OF SOLUTIONS OF CERTAIN FOURTH-ORDER DELAY DIFFERENTIAL EQUATIONS

By the use of the Liapunov functional approach, a new result is obtained to ascertain the asymptotic stability of zero solution of a certain fourth-order non-linear differential equation with delay. The established result is less restrictive than those reported in the literature.     

Synthesis,characterization, and electrical properties of a diazodiphenylene‐bridged Cu–phthalocyanine polymer

A diazodiphenylene‐bridged Cu–phthalocyanine polymer was synthesized from the diazonium salt of bensidine and the Cu(II) 1,8,15,22‐tetraaminophthalocyanine complex and characterized with Fourier transform infrared, ultraviolet–visible spectroscopy, and elemental analysis. The polymer was partially soluble in organic solvents such as dimethylformamide and tetrahydrofuran. The molecular weight of the soluble part of the polymer was investigated with ebullioscopy and viscosimetry methods in tetrahydrofuran. Both methods showed that the molecular weight of the polymer was much larger than that of the complex. The conductivity of the samples was measured with a four‐prop conductivity measuring device. Iodine and hydrogen chloride were doped to the polymer, and an increase of about 10⁴ S cm^?1 in the electrical conductivity was observed. The cyclic voltammogram of the diazodiphenylene‐bridged Cu–phthalocyanine polymer in contact with a LiClO₄ electrolyte exhibited two reductions and two reoxidations with high reversibility and electrochemical stability. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 5692–5698, 2006     

A Solution‐processible,n‐dopable polypyrrole derivative

In this study, soluble, n‐dopable, florescent, electrochromic polypyrrole derivative was synthesized through both chemical and electrochemical polymerization of 2‐[6‐(1H‐pyrrol‐1‐yl)hexyl]‐1H‐benzo[de]isoquinoline‐1,3(2H)‐dione (PyNI). The polymer synthesized through chemical polymerization had PL emission maxima at 471 and 543 nm and exhibited two redox couples at E_1/2,p = ?1.48 V and E_1/2,p = 1.12 V due to n‐type and p‐type doping, respectively. Electrochromic properties of electrochemically synthesized poly(PyNI) (PPyNI) were investigated via spectroelectrochemistry, kinetic studies, coloration efficiency, and colorimetry measurements. The optical band gap of PPyNI was calculated as 2.99 and 2.37 eV. Spectroelectrochemistry analysis of PPyNI reflected electronic transitions at 330–418 nm and 704 nm due to π–π* transition and charge carrier band formation, respectively. The polymer exhibited a switching time of 1.63 s and an optical contrast of 33.37%. Furthermore, dual‐type, complementary‐colored polymer electrochromic device in ITO/PPyNI/PEDOT/ITO configuration was assembled and characterized. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

New N,S-Substituted Dienes from Mono(thio)substituted-2-nitrohalo-1,3-diene and Some Amines

Mono(thio)substituted nitrodiene compound 1 reacted with 2a–f and yielded 3a–f in methylene chloride. Compound 1 gave 7 by the reaction with 6. Compounds 5a–c were obtained by the reactions of 4a–c with 1. 3a also has been structurally characterized using single-crystal X-ray diffraction analyses.     

Neue Thiosubstituierte Butadien- Und Butenin Verbindungen Aus Hexachlorbutenen Und Thiolen

2,3-Di-H-butene compound 1 gave compounds 3a-f , 4a , 4e , and 5a-d in the presence of thiols 2a-f and Et 3 N (or NaOH). Compound 7e was obtained from the reaction of 1,3-Di-H-butene 6 with naphthylthiol in DMF. In the presence of NaOH, compound 6 and 2 mmol of thiol 2g in EtOH gave compounds 8 , 9 , 10 , and 11 .