Materials Literature
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Hyperbranched poly(ether ketones), with a variety of chain end functional groups and controllable degrees of branching, are prepared by the polymerization of AB 2, AB 3, and AB 4 monomers. It is found that the choice of A and B, or the incorporation of dendritic and linear units into the AB x monomer structure, dramat…
Surface adsorptive properties of nanoscale MgO particles have been compared with more conventional samples. Morphologically the nanoparticles (autoclave prepared = AP-MgO) are unique and very different from the conventional samples (conventionally prepared = CP-MgO), and AP-MgO possesses more defects, edge and corner…
Optimized geometries, vibrational frequencies, and scale factors were calculated for furan and thiophene with the HF, MP2, LDA, BVWN, BLYP, and B3LYP methods of theory using the 6-31G**, cc-pVDZ, and cc-pVTZ basis sets. The agreement between the optimized and experimental geometries was in the order B3LYP, MP2, LDA, B…
Mechanistic studies of the oxidation of olefins by dioxygen plus aldehyde in the presence of metal complexes such as metalloporphyrins and metal cyclam complexes have been carried out. Epoxides were the predominant products, with trace amounts of allylic oxidation products. cis-Stilbene was oxidized to a mixture of ci…
The semiempirical tight-binding method was used to study the electronic structure of spherical PbS nanocrystals. The effects of spin−orbit coupling were included, and the calculated band gaps were found to agree well with previously published experimental values for PbS clusters. The size dependence of the band gaps w…
New graphite-like materials of composition BC 0.9-1.3 N 0.8-0.9 H 0.4-0.7 and BC 3.0-3.2 N 0.8-1.0 H 0.2-2, which are described as BCN(H) and BC 3 N(H), have been prepared by the interaction of acetonitrile with boron trichloride in a hydrogen and nitrogen atmosphere and acrylonitrile with boron trichloride, respectiv…
Thermochromism of a series of cast films of poly(3-alkylthiophenes) (P3ATs, A = hexyl, octyl, dodecyl, and hexadecyl) with different head-to-tail (HT) diad content (70−100%) was studied. The thermochromic behavior is found to be controlled by the HT diad content and the side chain length. P3ATs with moderate HT diad c…
The unusually strong, irreversible adsorption of monolayer quantities of the P 2 Mo 18 O 62 6 - anion on glassy carbon, highly ordered pyrolytic graphite, indium tin oxide, and gold-coated quartz electrodes was examined by electrochemical, spectroelectrochemical, and quartz crystal microgravimetric techniques. A very…
Diffuse reflectance FTIR spectra, X-ray diffraction patterns, and BET surface areas of La(NO 3 ) 3, La 2 (CO 3 ) 3, and La 2 O 3 have been obtained after various stages of thermal decomposition in the presence and absence of O 2 . In situ DRIFTS provided information about the surface chemistry taking place during the…
New chiral Schiff base complexes have been obtained by condensation of 2,2'-diamino-1,1'-binaphthalene or 1,2-diaminocyclohexane and various salicylaldehydes and by subsequent metalation with manganese, iron, cobalt, nickel, copper, or zinc. The complete (1)H and (13)C NMR characterization of the ligands is reported,…
Crystallization in oriented diblock copolymers containing poly(ethylene) (PE) has been investigated using simultaneous small-angle and wide-angle X-ray scattering (SAXS/WAXS). The orientation of the crystallized PE stems was deduced from the orientation of peaks in the WAXS pattern with respect to those in the SAXS to…
Nanoparticles of copper sulfide have been synthesized by reacting a copper ammonia complex with an equimolar thiourea solution in Triton-X 100/cyclohexane water-in-oil microemulsions. The presence of an exceptionally sharp and blue-shifted peak at 475 ± 2 nm in the UV−vis spectrum reveals the formation of quasi-monodi…
Results are presented from a variable-temperature solution-phase laser photolysis study of the 5 T 2 → 1 A 1 intersystem crossing in a series of related complexes: [Fe(tpen)](ClO 4 ) 2, [Fe(tppn)](ClO 4 ) 2, [Fe(tptn)](ClO 4 ) 2, [Fe( t -tpchxn)](ClO 4 ) 2, and [Fe(dpa) 2 ](ClO 4 ) 2 . The hexadentate ligands are form…
A diblock copolymer of deuterated styrene and isoprene (dPS−PI) with a small volume fraction of isoprene was chemically modified to incorporate pendant fluorinated side chains (“fingers”). The composition distribution of the diblock copolymers within a high molecular weight polystyrene (PS) homopolymer was determined…
Cubic platinum nanoparticles (4−18 nm) have been synthesized for the first time in solution by the controlled reduction of K2PtCl4 with hydrogen gas in the presence of sodium polyacrylate as a capping material. The nanoparticles are found to have fcc structures, similar to the bulk metal with {100} facets.
J. H. Clark and D. J. Macquarrie, Chem. Soc. Rev., 1996, 25, 303 DOI: 10.1039/CS9962500303
The segmental ligand 2-{6-[ N, N -diethylcarbamoyl]pyridin-2-yl}-1,1‘-dimethyl-5,5‘-methylene-2‘-(5-methylpyridin-2-yl)bis[1 H -benzimidazole] (L 2 ) reacts with stoichiometric amounts of Ln(III) (Ln = La−Nd, Sm−Tb, Tm−Lu, Y) and Zn(II) in acetonitrile to yield quantitatively and selectively the heterodinuclear triple…
Emeraldine refers to the semi-oxidized state of polyaniline and it can exist in the base form or the protonated form (salt) generated by treatment of the base form with an acid. Using a newly applied doping system NaReO4/HReO4, the investigation of the base–acid transition process of emeraldine has been carried out by…
The location and coordination of titanium in the titanosilicate mesoporous molecular sieve MCM-41 prepared from Ti(IV) ethoxide as the source of titanium was studied by XRD, IR spectroscopy, 29 Si MAS NMR, and XANES. The results are interpreted on the basis of isomorphous substitution of Ti for Si. XANES shows that ti…
Iron(III) binding to the DOPA-containing Mytilus edulis adhesive protein (Mefp1) has been studied by spectrophotometric titrations, electron paramagnetic resonance (EPR), and resonance Raman spectroscopies. At pH 7.0, two different forms of the iron−protein complex exist: one purple (λ max = 548 nm) and one pink (λ ma…