Materials Literature
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A series of novel meso-(8-substituted naphth-1-yl)porphyrins has been synthesized creating derivatives with a tight recognition environment above the porphyrin plane. The selective synthesis of single atropisomers is discussed. Condensation of bisnaphthaldehyde 12 with phenyldipyrromethane unexpectedly led to selectiv…
In this paper a high efficiency and flexible hybrid system representing a new total energy concept for the distributed power market is presented. The hybrid system is composed of a very small size (5 kW) micro gas turbine (named personal turbine—PT) presented in a companion paper by the authors coupled to a small size…
A survey of the October 2001 release of the Cambridge Structural Database [Cambridge Structural Database (1992). Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge, England] has uncovered approximately 675 separate apparently reliable entries under space groups P3, P3(1), P3(2) and R3; in approximately 1…
We consider the problem of nonlinear convection in horizontal mushy layers during the solidification of binary alloys. We analyse the oscillatory modes of convection in the form of two- and three-dimensional travelling and standing waves. Under a near-eutectic approximation and the limit of large far-field temperature…
Abstract Polyaniline (PAN), poly( o ‐bromoaniline) (POBA), and poly(aniline‐ co‐o ‐bromoaniline) (PABA) were synthesized by oxidative coupling. These polymers are protonated by 10–20% methane sulfonic acid (MSA) and 1 M HCl. The new polymer bases have greater solubility than that of PAN in common polar organic solvent…
Abstract The synthesis of chitosan methylcarbamate (ChMC) and ethylcarbamate (ChEC) is described by using a new methodology. Polymers with substitution degrees up to 63% for ChEC and 68.5% for ChMC were obtained. Derivatives with lower substitutions were acid soluble but those with higher ones were completely insolubl…
Computer animation of center of mass coordinates obtained from 800 ps molecular dynamics simulations of Cs-smectite hydrates (1/3 and 2/3 water monolayers) provided information concerning the structure and dynamics of the interlayer region that could not be obtained through traditional simulation analysis methods. Cs…
Antimony telluride doped with small concentrations of vanadium was recently identified as a diluted magnetic semiconductor. We present a study of the heat transport in single crystals of ${\mathrm{Sb}}_{2\ensuremath{-}x}{\mathrm{V}}_{x}{\mathrm{Te}}_{3}$ with $x=0,$ 0.01, 0.02, and 0.03. Thermopower and thermal conduc…
[reaction: see text] A dendrimer with rotaxane-like characteristics has been assembled under thermodynamic control from complementary wedge-shaped precursors by slippage in CH(2)Cl(2). The driving force for the self-assembly process is the molecular recognition that exists as a result of [N(+)-H.O] and [C-H.O] hydroge…
This paper reports a simple method for the multilayer immobilization of conjugated polymers, gold nanoparticles on solid supports. Poly(phenyenevinylene) functionalized with aldehyde and aminooxy groups was chemoselectively immobilized onto both glass and gold substrates via layer-by-layer deposition. The physical pro…
We describe a two-step conversion of C-alkylated zinc chlorins to zinc oxochlorins wherein the keto group is located in the reduced ring (17-position) of the macrocycle. The transformation proceeds by hydroxylation upon exposure to alumina followed by dehydrogenation with DDQ. The reactions are compatible with ethyne,…
An efficient procedure is described for catalyst recycling and easy product isolation in alkene epoxidation with hydrogen peroxide catalyzed by water-soluble iron(III) porphyrins in environmentally benign and ambient temperature ionic liquids.
The electronic absorption spectra of the bis(porphyrin) sandwich complexes of the metals Zr, Ce, and Th are studied with time-dependent density functional theory (TDDFT). A ground-state electronic structure analysis reveals that the highest occupied one-electron levels are, as expected, composed of the porphyrin a(1u)…
Ortho-carborane molecules have been inserted into single walled carbon nanotubes (SWNTs) and imaged directly by high resolution transmission electron microscopy (HRTEM); both discrete molecules and 'zig-zag' 1D chains of o-carborane 'petit pois' were observed to pack into the tubule capillaries.
The crystal structures of M(C(8)H(4)O(4))(H(2)O)(2), M = Mg, Mn, Fe and Co, have been determined by applying Monte Carlo simulated annealing techniques to synchrotron powder diffraction data and refined by the Rietveld method using both synchrotron and laboratory powder data. These isostructural compounds crystallize…
Abstract Clays are the most complicated objects in quantitative mineral analysis of sedimentary rocks. Complex quantitative analysis of clays comprises four major steps: measuring bulk quantities, quantifying the mixed layering, determining the three-dimensional organization, and measuring the particle size. Computeri…
Composite $({\mathrm{La}}_{0.67}{\mathrm{Ca}}_{0.33}{\mathrm{MnO}}_{3}{)}_{1\ensuremath{-}x}:(\mathrm{MgO}{)}_{x}$ films were prepared by metalorganic aerosol deposition on a (100)MgO substrate for different concentrations of the (MgO) phase $(0<~x<~0.8).$ At $x\ensuremath{\approx}0.3$ a percolation threshold in…
The hydrophobic channels in the structure of the dipeptide L-alanyl-L-valine act as supramolecular hosts for organic solvent molecules. In a series of data collections, it is demonstrated that small molecules like acetonitrile, methanol and acetone can be removed from the channels by drying without impairing the struc…
The tensile deformation behavior of poly(1-butene) and two of its ethylene copoloymers was studied at room temperature. This was done by investigating true stress−strain curves at constant strain rates, elastic recovery properties, and in-situ WAXS patterns during the deformation process. All samples showed a common r…
The structural chemistry of nanoscale materials encapsulated within single-walled carbon nanotubes (SWNTs) is reviewed. SWNTs form atomically thin channels within a restricted diameter range, and their internal van der Waals surfaces regulate the growth behavior of encapsulated crystals in a precise fashion, leading t…