Design of a photosystem to harvest visible-light into electrons: Photosensitised one electron redox reactions in organic synthesis
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Strong optical second-harmonic generation in a chiral diaminodicyanoquinodimethane system
A series of amine donor-substituted dicyanoquinodimethane molecules with large calculated hyperpolarizabilities has been investigated. Molecular and crystal structure details of a prototypical system are presented. Moderate to strong phase-matched powder second-harmonic generation is observed in chiral amine-substitut…
Thermal degradation of polymers in the melt, 2. Kinetic approach to the formation of volatile oligomers by thermal degradation of polyisobutylene
Abstract The thermal degradation of polyisobutylene is characterized by kinetics consisting of four types of intramolecular hydrogen abstraction (back‐biting) of primary (p) and tertiary (t) terminal macroradicals (R and R ) and the successive β scission at the inner position of the main chain. This reaction affords f…
New aspects of the synthesis of polymercaptals
Abstract The proton‐catalyzed polycondensation of aromatic aldehydes with aliphatic and aromatic α,ω‐dithiols leads to polymercaptals. The reaction may be carried out in bulk or solution. The bulk polycondensation was catalyzed by hexafluorophosphorous acid (HPF 6 ), formed photochemically by irradiation of the sample…
FTIR study of the adsorption of chromium carbonyl complexes on silica
IR spectra are reported of Cr(CO)6, (C6H6)Cr(CO)3 and (Me4C6H2)Cr(CO)3 adsorbed on silica which had been pretreated in vacuum at temperatures in the range 250–800 °C or in H2O or D2O vapour at 700 °C. Surface isolated silanol groups formed hydrogen bonds with arene rings in Cr complexes which also interacted with the…
Antiferromagnetic and hard-magnetic stabilization schemes for magnetoresistive sensors
Antiferromagnetic Ni-Mn and hard-magnetic CoPt-Cr stabilization schemes for magnetoresistive (MR) sensors are evaluated in this paper. Magnetic properties of Ni-Fe(bottom)/Ni-Mn(top), Ni-Mn/Ni-Fe, Co-Pt-Cr, Ni-Fe/Co-Pt-Cr and Co-Pt-Cr/Ni-Fe films used in various types of MR sensors are characterized, and the read perf…
Effects of tungsten on pitting corrosion resistance and impact toughness in the HAZ of duplex stainless steel ‐ study of weldability of high‐tungsten duplex stainless steel (1st Report)
Summary This paper describes an investigation of the effect of tungsten on the HAZ properties of duplex stainless steel in a programme to develop highly pitting corrosion resistant duplex stainless steel. The steels tested were modified SUS329J4L duplex stainless steel containing added tungsten. The welded joints prod…
Characterization of electrochemically prepared polyaminopyridines
Abstract Polymer‐modified electrodes have been prepared by electrochemical oxidation of 2‐aminopyridine and 4‐aminopyridine in acetonitrile and their chemical properties have been characterized. The polymer films thus prepared were insulators but can be doped with Ag + or Fe(CN) to produce semiconducting films. The do…
FT-IR spectroscopic studies of polyurethanes: IV. Studies of the effect of the presence of processing aids on the hemocompatibility of polyurethanes
Many types of proprietary processing aids are used by the manufacturers of polymer medical devices, which are difficult to completely eliminate from the end product. In such cases, it is important to investigate how such processing aids affect the properties of the materials. One such material is Pellethane and a most…
Novel Polyaromatic Quinone Imines. 2. Synthesis of Model Compounds and Stereoregular Poly(quinone imines) from Disubstituted Anthraquinones
Novel poly(quinone diimines) from anthraquinones symmetrically disubstituted with solubilizing ethyleneoxy or long chain alkoxy groups have been synthesized and characterized. The disubstituted anthraquinones 1,5-bis(2-methoxyethoxy)anthraquinone (EO 1 AQ), 1,5-bis(2-(2-methoxyethoxy)ethoxy)anthraquinone (EO 2 AQ), 1,…
Enhanced fluorescence of coumarin laser dye in the restricted geometry of a porous nanocomposite
We report here the dramatic increase in fluorescence intensity of 7-diethylamino-4-methylcoumarin (coumarin 1) laser dye in the restricted geometry of a pillared clay nanocomposite. The fluorescence intensity of the alumina-pillared fluorphlogopite– coumarin complex is about 6 times greater than that of the fluorphlog…
Stresses in a circular ring under two forces acting along a diameter
This paper analyses the stress state in a circular ring under two opposite forces on its outer boundary. The solution is obtained by using the complex variable method and the principle of superposition. Stress concentration factors are calculated for the ratio of inner and outer radii in the range 0–0.95 and are prese…
Conformational and Packing Energy Calculations for Isotactic Poly(vinylcyclohexane): Crystal Structure of Form I
The polymorphic behavior of poly(vinylcyclohexane) is discussed on the basis of conformational energy calculations on an isolated chain. The presence of two different modifications is in accordance with the energy minima present in the conformational energy maps. The packing of the chains in form I is analyzed on the…
Fine Structure of the Glass Transition in Amorphous Polymers: Slight Shoulder in the Shear H Spectrum at the L Peak
A slight shoulder in the shear relaxation spectrum ( H ) at the relaxation time for the main maximum of the retardation spectrum ( L ) was detected for three amorphous polymers: polystyrene, poly(vinyl acetate), and a slightly vulcanized natural rubber. This finding is discussed in terms of a distinctive manifestation…
Covalency in metal complexes of 1,4-diazabutadiene (dab). A density functional investigation of the electronic structures of [M(dab)2](M = Li, Ga or Co) and [Th(NH3)(NH2)3(dab)]
Density functional methods have been used to investigate the valence electronic structures of four complexes containing 1,4-diazabutadiene (dab) ligands. One compound was chosen from each of the four ‘blocks’ of the Periodic Table, viz.[Li(dab)2], [Ga(dab)2], [Co(dab)2] and [Th(dab)(NH3)(NH2)3]. The well documented st…
Interpenetrating Liquid Crystalline Polymer Networks
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTInterpenetrating Liquid Crystalline Polymer NetworksYue Zhao and Guoxiong YuanView Author Information Département de Chimie, Université de Sherbrooke, Sherbrooke, Québec, Canada J1K 2R1Cite this: Macromolecules 1996, 29, 3, 1067–106…
Molecular dynamics studies of titanylphthalocyanine crystals
Molecular dynamics calculations have been used to study the stability of a titanylphthalocyanine (TiOPc) crystal called Y-form. This crystal is of interest as a photoconductive material. A Parrinello–Rahman molecular dynamics calculation and a rigid-molecule intermolecular potential have been used in this study. The p…
Biofilms in freshwater ecosystems and their use as a pollutant monitor
A simple biofilm sampling device is used to collect representative microcoenoses from the River Alb in Germany. The samples are analyzed for their copper, cadmium and lead contents and the results are shown to be comparable to those from the techniques.
Oligo(furan-2,5-diylvinylene)s as π-conjugating spacers in linearly extended hybrid tetrathiafulvalene analogues
The synthesis of a new series of push–push systems based on furan-2,5-diylvinylene oligomers end-capped with l,3-dithiol-2-ylidene electron-releasing groups is described. 1H NMR spectroscopy and X-ray diffraction reveal that the molecules adopt a planar conformation stabilized by strong intramolecular interactions. El…
An interstitial pyrochlore formed by chemical intercalation of oxygen
Oxygen is intercalated, using a solution-based route at ambient temperature, into a pyrochlore oxide, thus establishing a new class of pyrochlore-based interstitial solid solutions: the specific system studied is Ce2Zr2O7 and compositions in the range Ce2Zr2O7 +x, 0 < x < 0.36 are obtained; the structure of the most o…