Materials Literature
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A series of carbosilane dendrimer generations, G0 to G3, with 4, 12, 36, and 108 end groups, respectively, has been functionalized with perfluorohexyl (C 6 F 13 −) groups on the surface. Quantitative perfluoroalkylation of the dendrimer surface was achieved via free radical addition of 3,3,4,4,5,5,6,6,7,7,8,8,8-tridec…
We have studied the formation of platinum nanoparticles in an ethanol−water mixture with an ethanol volume fraction of 0.6 by ethanol reduction of PtCl 6 2 - in the presence of poly( N -isopropylacrylamide) (PNIPAAm−Pt) by UV−visible spectrophotometry. As predicted by calculation, a maximum at 215 nm in the absorption…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTNoncovalent Synthesis of Layered and Channel Structures involving Sulfur-Mediated Hydrogen BondsV. R. Pedireddi, Swati Chatterjee, Anupama Ranganathan, and C. N. R. RaoView Author Information Chemistry & Physics of Materials Unit Jawaharlal Nehru Centre for Advanced Sc…
Cyclodextrins (CDs) were found to form inclusion complexes with aliphatic polyesters [−O(CH 2 ) x OCO(CH 2 ) 4 CO] n (where x = 2, 3, or 4) to give crystalline compounds. α- and γ-CD formed complexes with these polyesters in high yields, although β-CD gave complexes in moderate yields. Although the yields of the compl…
Bacterial Delta5-3-ketosteroid isomerase (KSI) catalyzes a stereospecific isomerization of steroid substrates at an extremely fast rate, overcoming a large disparity of pKa values between a catalytic residue and its target. The crystal structures of KSI from Pseudomonas putida and of the enzyme in complex with equilen…
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTLarge Dipole Moments of Phosphorus-Containing DendrimersMarie-Laure Lartigue, Bruno Donnadieu, Christophe Galliot, Anne-Marie Caminade, Jean-Pierre Majoral, and Jean-Pierre FayetView Author Information Laboratoire de Chimie de Coord…
The cell wall of a diatom is made up of a silica-based scaffold and organic macromolecules. Proteins located in the cell wall are believed to control morphogenesis of the species-specific silica structures of the scaffold. However, data that correlate distinct silica elements and specific proteins within the diatom ce…
An approach for the construction of diffusion-limited size-selective sensors is described based on the self-assembly of cyclic peptides into tubular channels in organosulfur self-assembled monolayers on gold films. An eight-residue cyclic peptide of alternating units of d -Leu and l -Trp amino acid residues was incorp…
Electrochemical insertion of Li into a series of “nanocomposites” comprised of alternating V 2 O 5 sheets and conductive polymer layers [polypyrrole (PPY) and polyaniline (PANI)] was examined and compared to the pristine V 2 O 5 material in terms of reversibility, Li site occupancy, and Li diffusion coefficients, and…
Genetic research programs such as the human genome project have demonstrated the need for selective detection of nucleic acids at ultralow concentrations (McKusik, V. A. FASEB J. 1991, 5, 12−20. Cui, X.; et al. Proc. Natl. Acad. Sci. U.S.A. 1989, 89, 9389−9393). Current detection techniques require amplification of th…
Using molecular-dynamics computer simulations, we investigate the dynamics of the rotational degrees of freedom in a supercooled system composed of rigid, diatomic molecules. The interaction between the molecules is given by the sum of interaction-site potentials of the Lennard-Jones type. In agreement with mode-coupl…
Packings of spheres serve as useful models of the geometry of many physical systems; in particular, the description of the void region in such packings (the region not occupied by the spheres) is crucial in many studies. The void region is, in general, composed of disconnected cavities. We present an algorithm for dec…
The crystal structures of three porphyrin diacid species, [H 4 OEP](ClO 4 ) 2, [H 4 TPP](ClO 4 ) 2, and [H 4 TMP](ClO 4 ) 2, have been determined from low-temperature X-ray diffraction data to delineate how the peripheral substituents of the porphyrin affect the overall molecular flexibility . [H 4 OEP](ClO 4 ) 2 (|C…
A new method for the patterning of ionic layer-by-layer assembled films with micron-sized features is presented. Self-assembled monolayers (SAMs) were used as templates to direct the deposition of sulfonated polystyrene (SPS) and poly(diallyldimethylammonium chloride) (PDAC) multilayers onto a surface. Both polyelectr…
The homopolymerization of 2-((2-bromopropionyl)oxy)ethyl acrylate (BPEA) by atom transfer radical polymerization (ATRP), a “living”/controlled radical polymerization system, has yielded a hyperbranched polymer. Variation of the reaction conditions and especially the concentration of copper(II) in the polymerization sy…
We use a Monte Carlo algorithm to simulate the director field around a spherical inclusion in a uniform nematic liquid crystal matrix. The resulting structure crucially depends on the relative strength of the nematic bulk elasticity and the director anchoring on the particle surface. When this anchoring is weak, the d…
Extensive studies that have been conducted on the Pb(Mg 1/3 Nb 2/3 )O 3 (PMN) family of relaxor ferroelectrics have led to the establishment and acceptance of the“space‐charge” model as a basis for explaining their structures and dielectric properties. In this model, the arrangement of the metal cations on the octahed…
In order to study the freezing/melting behavior of pore water, we performed x-ray diffraction measurements of water confined inside the cylindrical pores of two kinds of siliceous MCM-41 with different pore size and one kind of aluminosilicate MCM-41 as a function of temperature. The results show that its freezing/mel…
Clustering has an important effect on the tetragonal‐cubic transformation of barium titanate (BaTiO 3 ) particles. Small particles that would be cubic if they were by themselves can be tetragonal if they are in a cluster. The effects of clustering are shown in the behavior of the c/a ratio of the particles and the ent…
The self-condensing vinyl polymerization (SCVP) of 2-((2-bromopropionyl)oxy)ethyl acrylate (BPEA) has resulted in the formation of hyperbranched polyacrylates. The polymerization mechanism used to polymerize the BPEA was atom transfer radical polymerization (ATRP), a “living”/controlled radical polymerization. This pa…