Materials Literature
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Magnetic and electrochemical interactions between two redox-active, paramagnetic {Mo(Tp*)(NO)Cl} fragments [Tp* = tris(3,5-dimethylpyrazolyl)hydroborate] attached to either end of various bis(pyridyl) bridging ligands may be related to the substitution pattern, conformation, length, and symmetry of the bridge. The sig…
Several unsymmetrically substituted TTFs bearing the S(CH2)2CN protecting group have been prepared by standard cross coupling in triethyl phosphite from the key intermediate 4,5-bis(2′-cyanoethylsulfanyl)1,3-dithiol-2-one 1 and an appropriate 1,3-dichalcogenole-2-chalcogenone, 2–8. TTFs 10, 11 and 12 of type I have be…
The stability of weakly flocculated, nonaqueous suspensions of aluminum oxide with adsorbed poly(methyl methacrylate) (PMMA) layers as a function of nonadsorbed PMMA volume fraction was studied through rheological measurements and optical microscopy. In the absence of nonadsorbed polymer, suspensions exhibited strong…
Both discharge capacity and charge–discharge cycle life of MgNi negative electrodes prepared by mechanical alloying (MA) are greatly improved by surface modification with graphite using a planetary mill.
A general theoretical framework for the study of anisotropic composition fluctuations about an ordered block copolymer phase is developed. The approach is based on the idea that, in order to study the effects of fluctuations around an ordered broken symmetry phase, the theory must be formulated as a self-consistent ex…
The three-dimensional structure of amyloid beta peptide (25-35), which has neurotoxic activity, in lithium dodecyl sulfate micelles was determined by two-dimensional 1H NMR spectroscopy with simulated annealing calculations. A total of 20 converged amyloid beta peptide structures were obtained on the basis of 110 expe…
The lattice cluster theory (LCT) is used to study the influence of monomer structure, i.e., short chain branching, on the miscibility of binary polymer blends. The systems are chosen as corresponding to united atom models of the monomer structures in the binary polyolefin blends studied by Graessley and co-workers. We…
The mechanism of polymerization of ε-caprolactone (εCL) initiated with aluminum isopropoxide (Al(O i Pr) 3 ) trimer (A 3 ) and/or tetramer (A 4 ) carried out in the presence of ethanol, 2-propanol, 1,2-ethanediol, 1,5-pentanediol (PD), and poly(ethylene glycol) as chain-transfer agents was studied. It has been establi…
Poly( l, l -lactide) microspheres were synthesized directly during the ring-opening precipitation polymerizations of l, l -lactide. The polymerizations were carried out in heptane−1,4-dioxane (4:1 v/v) mixed solvent in the presence of various poly(dodecyl acrylate)- g -poly(ε-caprolactone) copolymers (poly(DA−CL)) use…
A novel manganese(IV) monomer, [Mn(IV)(Me(3)TACN)(OMe)(3)](PF(6)), has been synthesized in methanol by the reaction of MnCl(2) with the ligand, N,N',N"-trimethyl-1,4,7-triazacyclononane (Me(3)TACN), in the presence of Na(2)O(2). The resulting product was isolated as the red/brown crystalline hexafluorophosphate salt.…
The electrochemical synthesis of linear symmetrical octaethylporphyrin−octaethylporphyrin and unsymmetrical tetraphenylporphyrin−octaethylporphyrin dimeric porphyrins with one viologen as a spacer and of their precursor porphyrin monomers is reported. The mechanism of the electrochemical substitution leading to the di…
Abstract The principal objectives and methods of surface modification of polymers are reviewed in this paper. The techniques covered include physical, chemical, mechanical and biological methods.
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTMechanism of Rate Enhancement Using Organic Acids in Nitroxide-Mediated Living Free-Radical PolymerizationsRichard P. N. Veregin, Peter G. Odell, Lora M. Michalak, and Michael K. GeorgesView Author Information Xerox Research Centre…
The reaction of tungstate ions with the gamma-10-tungstosilicate in mixed water-ethanol (v/v) yields the corresponding isomer of the 12-tungstosilicate isolated as its tetrabutylammonium salt. It was characterized by means of (183)W NMR, infrared, Raman, and UV spectroscopies and was identified with the isomer resulti…
The relative arrangement of sodium and lithium ions in mixed-alkali silicate glases of composition [(Li 2 O) 1- y (Na 2 O) y ] x [SiO 2 ] 1- x ( y = 0.25, 0.50, and 0.75; x = 0.40 and 0.50) is studied by 23 Na−{ 7 Li} spin echo double-resonance (SEDOR) NMR spectroscopy, supplemented by additional 23 Na−{ 6 Li} experim…
Solid-state properties of the stoichiometric complexes formed by sodium poly(α, l -glutamate) and oppositely charged low molecular weight surfactants (alkyltrimethylammonium bromides) were examined by circular dichroism, infrared, and X-ray diffraction techniques. The polypeptide chains in the complexes were shown to…
Core and valence level photoemission and electron energy loss (EELs) spectra of MoO2 and WO2 have been measured. Metal–metal bonding in these distorted rutile dioxides splits the metal 4d or 5d conduction band into two components, with a significantly bigger splitting for WO2 than MoO2. The O 2p bandwidth is also foun…
The kinetics of hydrogen plasma in an afterglow region has been simulated to distinguish remote plasma treatment from conventional (direct) plasma treatment. A simulation shows the possibility that remote hydrogen plasma treatment can enhance interaction reactions with hydrogen radicals relative to those with electron…
A series of homo- and heterotrinuclear complexes containing three face-sharing octahedra has been synthesized by using the pendent arm macrocyclic ligands 1,4,7-tris(3,5-dimethyl-2-hydroxybenzyl)-1,4,7-triazacyclononane, L 0 H 3, and 1,4,7-tris(4- tert -butyl-2-mercaptobenzyl)-1,4,7-triazacyclononane, LH 3: [{L 0 Ni I…
The synthesis, optical spectroscopy, photophysical properties, electrochemistry, and X-ray photoelectron spectroscopy of a series of [5,10,15,20-tetrakis(perfluoroalkyl)porphinato]zinc(II) complexes and their free base analogs are reported. The title compounds were prepared by a condensation methodology that utilizes…