Self-association of a 1,3,4-oxadiazole-containing dendrimer
A first-generation dendrimer, which consists of electron-deficient benzene and oxadiazole rings, forms π-stacks in solution as evidenced by NMR and vapour-pressure osmometry.
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The Formation of Se2-: A New Resonance Raman Feature in the Photochemistry of Zeolite-Encapsulated Selenium
This Raman spectroscopic study on selenium incorporated in Nd−Y zeolite presents new aspects of the photochemistry of selenium. The formation of the Se 2 - radical anion has been established from its resonance Raman spectrum, consisting of ten almost equidistant bands between 328 and 3220 cm - 1 on the low-energy side…
Assembly of Amphiphilic Phenylacetylene Macrocycles at the Air−Water Interface and on Solid Surfaces
The assembly of amphiphilic phenylacetylene macrocycles (PAMs), with molecular structures that vary in terms of the nature and orientation of their pendant functional groups, has been studied on a Langmuir−Blodgett trough and after transfer onto solid substrates. These monolayer films are of interest as two-dimensiona…
The Synthesis of η2-β-Vinylpyrrole Complexes and Their Conversion to Highly Substituted Indoles
A series of 4,5-η 2 -Os(II)pentaammine-3-vinylpyrrole complexes are synthesized from the corresponding 1-methylpyrrole complex by an electrophilic addition at the β-carbon, C(3), of the pyrrole ring. Four independent synthetic routes to β-vinylpyrrole complexes are described, each introducing different functionality o…
Endothelial cell seeding improves patency of synthetic vascular grafts: manual versus automatized method
Lack of an endothelial surface is the most important variable causing the relatively poor patency of synthetic bypass grafts. This study was designed to investigate the effect of endothelial cell seeding on small-diameter Dacron grafts seeded with microvascular endothelial cells from omentum, and to evaluate two metho…
Study of ‘wet’ polymer latex systems in environmental scanning electron microscopy: some imaging considerations
Environmental scanning electron microscopy has been used to study ‘wet’ polymer latex films. Comparison of the results obtained by imaging in nitrogen and nitrous oxide gas and water vapour has provided insight into a variety of different contrast phenomena. Notably, it was found that edge definition and fine features…
Deformation and Relaxation Processes of Mono- and Bilayer Domains of Liquid Crystalline Langmuir Films on Water
Flow deformation and relaxation of mono- and bilayer domains of a thermotropic liquid crystal at the air−water interface have been studied by means of simultaneous application of extensional flow fields and Brewster angle microscopy measurements. In an extentional flow, mono- and bilayer domains are found to be distor…
Communication between Porphyrin Rings in the Butadiyne-Bridged Dimer Ni(OEP)(μ-C4)Ni(OEP): A Density Functional Study
The electronic structure and spectra of a family of nickel porphyrin complexes are analyzed using approximate density functional theory (DFT). The three complexes, Ni(OEP), Ni(OEP-C 4 SiMe 3 ), and Ni(OEP)(μ-C 4 )Ni(OEP) represent a logical increase in complexity starting from a simple metalloporphyrin. The spectra of…
Effects of Radiation on Materials: 17th International Symposium
Description STP 1270 features the latest information from the world's leading experts on how radiation impacts a wide range of metals. This extensive volume includes 68 peer-reviewed papers organized into 8 comprehensive categories: Modeling of Controlling Mechanisms -- 8 papers explore mechanisms controlling the beha…
Surface-Chlorinated Ceria and Chlorine-Containing Reduced Pd/CeO2 Catalysts. A FTIR Study
Adsorption of CO, used as infrared molecule probe, was performed at room temperature or at low temperature (140 K), on either chlorine-free or chlorine-containing ceria, in order to investigate both the chlorine effect and the ceria reduction state. On ceria and Pd/ceria catalysts, chlorine acts as an electronegative…
A Class of Halide-Supported Trinuclear Nickel Clusters [Ni3(μ3-L)(μ3-X)(μ2-dppm)3]n+(L = I-, Br-, CO, CNR; X = I-, Br-;n= 0, 1; dppm = Ph2PCH2PPh2): Novel Physical Properties and the Fermi Resonance of Symmetric μ3-η1Bound Isocyanide Ligands
The dihalide capped trinuclear nickel clusters Ni 3 (μ 3 -X) 2 (μ 2 -dppm) 3 (X = I ( 1a ), Br ( 1b ); dppm = Ph 2 PCH 2 PPh 2 ) were synthesized and converted to their respective monocations [Ni 3 (μ 3 -X) 2 (μ 2 -dppm) 3 ] + (X = I ( 1a + ), Br ( 1b + )) via a single electron oxidation. Clusters 1a and 1a + were cha…
Rheological Model for the Mechanical Properties of Myofibrillar Protein-Based Films
A phenomenological rheological model was developed to describe the molecular interactions and predict the mechanical properties of fish myofibrillar protein-based films, irrespective of their thickness. The model was built of a parallel array of Maxwell and elastic elements in which a fracture element was introduced.…
Effects of Cross-Linking on the Morphology of Structured Latex Particles. 1. Theoretical Considerations
Cross-linking of the seed latex polymer introduces elastic forces into the thermodynamic analysis of the morphology of composite particles. By determining the elastic storage energy necessary to maintain a deformation within the seed latex particle (as in an occlusion of second-stage polymer), it can be combined with…
Novel Thermally Stable Polymer Materials for Second-Order Nonlinear Optics
A novel method of preparing thermally stable thin films with intrinsic second-order nonlinear optical activity is described. Design and synthesis yielded new ferroelectric bifunctional liquid crystalline acrylate monomer mixtures with a fast electro-optical response in the chiral smectic C (SmC*) phase. The ferroelect…
NaCu4S4, a Simple New Low-Dimensional, Metallic Copper Polychalcogenide, Structurally Related to CuS
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTNaCu4S4, a Simple New Low-Dimensional, Metallic Copper Polychalcogenide, Structurally Related to CuSXiang Zhang, Mercouri G. Kanatzidis, Tim Hogan, and Carl R. KannewurfView Author Information Department of Chemistry, Michigan State University East Lansing, Michigan 48…
A Strategy for Total Synthesis of Complex Cardenolides
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTA Strategy for Total Synthesis of Complex CardenolidesWei Deng, Mark S. Jensen, Larry E. Overman, Paul V. Rucker, and Jean-Paul VionnetView Author Information Department of Chemistry, 516 Physical Sciences 1, University of California, Irvine, California 92697-2025 Cite…
Kinetics of esterification of acetic acid with propyl alcohol by heterogeneous catalysis
Kinetic data on the esterification of acetic acid with propyl alcohol catalyzed by the ion exchange resin DOWEX MONOSPHERE 650 C have been obtained using a stirred batch reactor. It was checked if there is an influence of pore diffusion and film resistance on the reaction rate when varying reaction temperature, initia…
Heterobimetallic Clusters of Copper(I) with Trithiotungstate and Trithiomolybdate. Synthesis and Characterization of the Octanuclear Clusters [Et 4 N] 4 [M 4 Cu 4 S 12 O 4 ] (M = Mo, W) and the Dodecanuclear Clusters [M 4 Cu 4 S 12 O 4 (CuTMEN) 4 ] (M = Mo, W; TMEN = N , N , N‘ , N‘ -Tetramethylethylenediamine)
Synthetic methods for [Et(4)N](4)[W(4)Cu(4)S(12)O(4)] (1), [Et(4)N](4)[Mo(4)Cu(4)S(12)O(4)] (2), [W(4)Cu(4)S(12)O(4)(CuTMEN)(4)] (3), and [Mo(4)Cu(4)S(12)O(4)(CuTMEN)(4)] (4) are described. [Et(4)N](2)[MS(4)], [Et(4)N](2)[MS(2)O(2)], Cu(NO(3))(2).3H(2)O, and KBH(4) (or Et(4)NBH(4)) were used as starting materials for…
Direct Energy Transfer Studies of the Domain−Boundary Interface in Polyisoprene−Poly(methyl methacrylate) Block Copolymer Films
Direct nonradiative energy transfer (DET) experiments were carried out on five polyisoprene−poly(methyl methacrylate) diblock copolymers with polyisoprene volume fractions ranging from 0.07 to 0.5 (polyisoprene microdomains dispersed in a poly(methyl methacrylate) matrix). These experiments yield the ratio R /δ of the…
Synthesis of Hyperbranched, Hydrophilic Fluorinated Surface Grafts
The synthesis of 60−1000 Å thick films of fluorinated polymers on gold and silica substrates via amidation of layered, hyperbranched poly(acrylic acid) surface-graft films with a fluorinated octylamine is described. These syntheses proceed either by formation and fluoramidation of layers of poly(acrylic acid) or by st…