Materials Literature
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Four dyes (2-DASPI, 4-DASPI, LDS698, and LDS722) derived from the stilbazolium skeleton have been intercalated into optically transparent Na−fluorine mica layers. X-ray diffraction data show that the long axis of DASPI dyes is aligned parallel to the layer, largely maintaining their solution phase structure. On the ot…
The oxidation of sulfides and sulfoxides by permanganate in anhydrous acetone solutions is catalyzed by Lewis acids such as iron(III) chloride, zinc chloride, and mercury(II) chloride. The reaction kinetics unequivocally confirm that the function of these catalysts is to activate the oxidant by forming permanganate/Le…
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTWater-Soluble Self-Doped Conducting Polyaniline CopolymerWusheng Yin and Eli RuckensteinView Author Information Department of Chemical Engineering, State University of New York at Buffalo, Buffalo, New York 14260 Cite this: Macromol…
Hyperbranched polyglycerols (DP n = 23−83; M w / M n = 1.2−1.5) as well as their propoxylated derivatives were esterified to different extents (23%−100%) with various carboxylic acids (C2 to C18, benzoic, biphenylcarboxylic, and benzoic acid). Composition and molecular weight of the hyperbranched polyether scaffolds w…
The condensation of an aldehyde with a dipyrromethane bearing a sterically unhindered aryl substituent at the 5-position typically results in low yield and a mixture of porphyrin products derived from acidolytic scrambling. We have developed a concise nonscrambling synthesis of such trans-porphyrins that takes advanta…
13 C NMR shift and spin−lattice relaxation measurements have been used to investigate 13 CO (ex MeOH) on fuel cell grade Pt electrodes (having average particle diameters of 2, 2.5, and 8.8 nm) in an electrochemical environment from 80 to 293 K at 8.47 and 14.1 T. The temperature dependence of the 13 C spin−lattice rel…
Static electrical and magnetic properties of single crystal BaVS_3 were measured over the structural (T_S=240K), metal-insulator (T_MI=69K), and suspected orbital ordering (T_X=30K) transitions. The resistivity is almost isotropic both in the metallic and insulating states. An anomaly in the magnetic anisotropy at T_X…
The phase diagram of BaVS3 is studied under pressure using resistivity measurements. The temperature of the metal to nonmagnetic Mott insulator transition decreases under pressure, and vanishes at the quantum critical point p_cr=20kbar. We find two kinds of anomalous conducting states. The high-pressure metallic phase…
We calculate the first hyperpolarizability (β) of several thiazole and thiophene analogues of donor−acceptor stilbene compounds using the ZINDO (sum-over-states) formalism. Because of the inherent dipolar nature of thiazole, in which C2 is electron-poor and C5 is electron-rich, the relative orientation of the thiazole…
Single-file diffusion, prevalent in many processes, refers to the restricted motion of interacting particles in narrow micropores with the mutual passage excluded. A single-filing system was developed by confining colloidal spheres in one-dimensional circular channels of micrometer scale. Optical video microscopy stud…
Confocal microscopy was used to directly observe three-dimensional dynamics of particles in colloidal supercooled fluids and colloidal glasses. The fastest particles moved cooperatively; connected clusters of these mobile particles could be identified; and the cluster size distribution, structure, and dynamics were in…
The tensile strengths of individual multiwalled carbon nanotubes (MWCNTs) were measured with a "nanostressing stage" located within a scanning electron microscope. The tensile-loading experiment was prepared and observed entirely within the microscope and was recorded on video. The MWCNTs broke in the outermost layer…
Chemical sensors based on individual single-walled carbon nanotubes (SWNTs) are demonstrated. Upon exposure to gaseous molecules such as NO(2) or NH(3), the electrical resistance of a semiconducting SWNT is found to dramatically increase or decrease. This serves as the basis for nanotube molecular sensors. The nanotub…
A microscopic theory of the structure of compressible associating AB regular heteropolymer fluids is proposed based on polymer integral equation methods. The theory is employed to systematically explore, as a function of temperature, the influence of sticky group attractive energy, concentration, degree of blockiness,…
Al-, Ti-, and Zr-containing silica-based pillars of which Si 4+ is isomorphously substituted by each ion have been formed between the silicate layers of H-ilerite by intercalation of octylamine and mixed alkoxides. The resultant silica-based pillared materials have a BET surface area of about 800 m 2 /g at 600 °C and…
A new manganese(II) phosphate templated by ethylenediamine, (C 2 H 10 N 2 )[Mn 2 (HPO 4 ) 3 (H 2 O)], has been prepared by hydrothermal synthesis and characterized by single-crystal diffraction data and spectroscopic and magnetic techniques. The compound crystallizes in the monoclinic space group P 2 1 / n with a = 21…
The fluorescence spectra of 9-anthracenecarboxylic acid (9ACA) were studied in surfactant solutions of sodium dodecyl sulfate and Triton X-100 as a function of surfactant concentration. In addition to an anthracene-like sharp fluorescence, a broad fluorescence with a peak around 470 nm appeared at 330 nm excitation ab…
A series of polyoxometalates have been synthesized and evaluated for their inhibitory effects on HIV-1(III(B)) and HIV-1(ROD) replication in MT-4 cells. All compounds showed activity against HIV-1 and HIV-2, but the antiviral potency of the heteropolytungstates varied considerably depending on their chemical structure…
A new general approach for improving polymer substratum biocompatibility is proposed. In a first example, polysulfone (PSf) film was modified by covalent end-on grafting of poly(ethylene glycol) (PEG) (2, 5, and 10 kDa) using well-defined, photoreactive α-4-azidobenzoyl β-methoxy PEG conjugates (ABMPEG). After adsorpt…
The formation processes of the silica nanotubes by a surfactant-assisted templating mechanism were elucidated in a laurylamine hydrochloride (LAHC)/tetraethoxysilane (TEOS) system by measuring the evolution of the shape and size of surfactant/silicate molecular assemblies with small-angle X-ray scattering, together wi…