Materials Literature
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Surface molecular aggregation structure and surface molecular motions of high-molecular-weight polystyrene/low-molecular-weight poly(methyl methacrylate) (HMW-PS/LMW-PMMA) blend films were investigated on the basis of X-ray photoelectron spectroscopic measurements and scanning force microscopic observations. Monodispe…
An expression is given for the electronic polarization of an insulating crystal within the ultrasoft pseudopotential scheme. The pseudopotential charge-augmentation terms modify the usual Berry-phase expression, and also give rise to a second term that takes the form of a conventional expectation value.
Atomic force microscopy (AFM), neutron reflection (NR) and secondary ion mass spectroscopy (SIMS) are used to examine phase separation in symmetrically segregating thin polymer blend films (≤1000 Å). Phase separation in the film leads to undulations of the liquid−air interface, provided the film is sufficiently thin t…
Small block copolymers, consisting of a hydrophilic poly(ethylene glycol) block and a second hydrophilic moiety which strongly interacts with alkaline earth ions, were employed to template the precipitation of calcium carbonate from aqueous solution. Depending on the type of polymeric functionalization pattern used, i…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTA Survey of Applications of PolyoxometalatesDimitris E. KatsoulisView Author Information Dow Corning Corporation, Central Research and Development, Midland, Michigan 48686 Cite this: Chem. Rev. 1998, 98, 1, 359–388Publication Date (Web):January 17, 1998Publication History Re…
Ein Metall&ararr;π*(Carben)-Charge-Transfer-Übergang in Lösung bei Raumtemperatur wurde erstmals bei der Titelverbindung nachgewiesen. Dieser ungewöhnliche, sechskernige Platinamakrocyclus entsteht durch Selbstorganisation aus je sechs Dicarben-Platin(II)-Einheiten und Cyanidliganden, wobei die Platinzentren sechs Eck…
The synthesis and characterization of composite inorganic−polyimide films is described by adding diaquotris(2,4-pentanedionato)lanthanum(III) to soluble, low dielectric, colorless polyimides formed from 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride/1,3-bis(3-aminophenoxy)benzene (6FDA/APB), and 6FDA/2,2-bi…
Zwei Pyrrolringe sind Bestandteil der aromatischen Struktur von Porphyrin. Daher sollte es eher als 22π-Elektronensystem (siehe rechts) denn als [18]Annulen beschrieben werden. Dagegen bevorzugen sowohl das Dianion als auch die Metallkomplexe grundlegend andere elektronische Strukturen.
Treatment of titanium tetrachloride (2 equiv) with dimethyl diselenide or diethyl diselenide (1 equiv) in hexane at 0 degrees C, followed by crystallization at -20 degrees C, afforded (TiCl(4))(2)(Se(2)(CH(3))(2)) (78%) and (TiCl(4))(2)(Se(2)(CH(2)CH(3))(2)) (63%), respectively, as red and orange crystalline solids. (…
Gold nanoparticles were generated by ultraviolet irradiation of Langmuir−Blodgett (LB) films of octadecylamine (ODA), 4-hexadecylaniline (HDA), and benzyldimethylstearylammonium chloride monohydrate (BDSAC) deposited from aqueous HAuCl 4 subphases. In contrast, no gold crystals were observed in irradiated LB films pre…
In a combined modeling and experimental study the twin interface in saccharin crystals has been used as the basis for energetic calculations and visualization of the solid−solid interface. A methodology has been developed that has wide applicability to a range of interfaces between crystalline materials.
Reported here are both STM images and spatially resolved tunneling spectra of four different polyoxometalate (POM) structural class members: Keggin structure, H(3)[PW(12)O(40)] (spherical); Finke-Droege (FD) structure, Na(16)[Cu(4)(H(2)O)(2)(P(2)W(15)O(56))(2)] (prolate spheroidal); Wells-Dawson (WD) structure, H(7)[P…
The segmental ligands bis{1-alkyl-2-[6'-(N,N-diethylcarbamoyl)pyridin-2'-yl]benzimidazol-5-yl}methane (alkyl = methyl (L(5)), ethyl (L(6))) react with lanthanide perchlorates (Ln = La, Eu, Gd, Tb) in acetonitrile to yield the f-f dinuclear homotopic triple-stranded helicates [Ln(2)(L(i)())(3)](6+) (i = 5, 6) under the…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTHalf-Integer-Spin Small Molecule Magnet Exhibiting Resonant Magnetization TunnelingSheila M. J. Aubin, Neil R. Dilley, Michael W. Wemple, M. Brian Maple, George Christou, and David N. HendricksonView Author Information Department of Chemistry-0358 University of Califor…
Sehr stabile Dimere einer Klasse leicht zugänglicher selbstkomplementärer Bausteine für supramolekulare Aggregate bilden sich in Lösung und im Festkörper durch Assoziation über eine Donor-Acceptor-Donor-Acceptor-Anordnung von vier H-Brückenköpfen. Eine weitere, intramolekulare H-Brücke in dem rechts gezeigten Molekül…
The high-resolution crystal structure for [Co(OEP)(NO)] shows that the axial Co−N(NO) vector is tilted from the normal to the porphyrin plane. The off-axis tilt is correlated with an asymmetry in the equatorial Co−Np bond distances.
Ultrathin films of two perylene dyes, 3,4,9,10-perylenetetracarboxylicdianhydride (PTCDA) and N, N ‘-di- n -butylperylene-3,4,9,10-bis(dicarboximide) (C4−PTCDI), have been grown on the (001) faces of freshly cleaved single crystal, NaCl, KCl, and KBr. Tapping mode AFM studies of these materials show that their crystal…
The twelve phosphide oxides RZnPO (R = Y, La-Nd, Sm, Gd-Tm) and the nine arsenide oxides (R = Y, La-Nd, Sm, Gd-Dy) have been prepared by reaction of the rare earth elements, ZnO, and phosphorus or arsenic, respectively, in a NaCl/KCl flux. The compounds RZnPO (R = Y, Pr, Nd, Sm, Gd-Tm) crystallize with a new trigonal…
Catalytic activities and deactivation characteristics of oxides-supported nickel catalysts for the reaction of methane reforming with carbon dioxide were investigated. The dynamic carbon deposition on various nickel catalysts was also studied by a thermogravimetric method. Among the catalysts prepared, Ni/La 2 O 3, Ni…
Clavaminate synthase (CS) is one member of a large class of non-heme iron enzymes that require α-ketoglutarate (α-KG) as a cosubstrate. While the majority of this class catalyzes the hydroxylation of unactivated C−H bonds, CS is unusual in that in addition to performing hydroxylation chemistry, it also catalyzes the k…