Materials Literature
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Two state-of-the-art computational approaches: quantum Monte Carlo (QMC), based on accurate total energies, and GW with exciton effects (GW-BSE), based on perturbation theory are employed to calculate ionization potentials, electron affinities, and first excited singlet and triplet energies for the silane and methane…
A needle trap device (NTD) and commercial poly(dimethylsiloxane) (PDMS) 7-microm film thickness solid-phase microextraction (SPME) fibers were used for the sampling and analysis of aerosols and airborne particulate matter (PM) from an inhaler-administered drug, spray insect repellant, and tailpipe diesel exhaust. The…
The low-temperature behavior of the selective catalytic reduction (SCR) process with feed gases containing both NO and NO 2 was investigated. The two main reactions are 4NH 3 + 2NO + 2NO 2 → 4N 2 + 6H 2 O and 2NH 3 + 2NO 2 → NH 4 NO 3 + N 2 + H 2 O. The “fast SCR reaction” exhibits a reaction rate at least 10 times hi…
Clinopyroxenes from the Campiglia Marittima skarn range from hedenbergite to johannsenite (Jh(7) to Jh(100)) Twenty single-crystals were selected for structural refinements and electron microprobe analyses. (100) twins were present acid treated using a halved data set. End-member johannsenite is best approximated by t…
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The amino-derivatized cyclotriveratrylene analogue, triaminotrimethoxytribenzocyclononene [CTV(NH2)3(OMe)3], 1, is readily converted into triply substituted imine compounds [CTV(sal)3(OMe)3], 2, in high yield by treatment of the acid salt of 1 with a variety of substituted salicylaldehydes. Cleavage of the protecting…
In connection with a study aimed at the evaluation of electronic effects in spiro-dicorrole (1a) and its binuclear Ni(II) complex (1b) we became interested in gem-dimethyl-substituted cyclotetrapyrrole (2a) and the corresponding Ni(II) complex (2b). Attempts to prepare 2a as the 12,13,16,17-tetraethyl-2,3,7, 8-tetrame…
One of the few examples of molecules with D3 symmetry is the novel P8Se3 cage molecule (see structure). This species was obtained as an adduct to copper iodide. This phosphoselenide cage can be formally derived from the polyphosphide “ufosane” P113− through the substitution of P− by Se.
This paper proposes a general strategy to define molecular orbitals which are especially adapted to the calculation of the energy difference between two states. These orbitals are shown to be eigenvectors of blocks of the difference between the density matrices relative of the two states. They may be used for rational…
Die eindimensionale Ausbreitung eines Multiporphyrinaggregates auf eine Länge von einigen Hundert Nanometern wurde durch die mehrfache komplementäre Koordination eines Imidazol-substituierten Bis-Zinkporphyrins erreicht (siehe Bild). Die Länge des Aggregats hängt zum einen vom Lösungsmittel ab und kann zum anderen dur…
Picosecond to submillisecond photochromic reactions of 2,4-diphenyl-2H-benzopyran and 2,2,4-triphenyl-2H-benzopyran have been investigated by time-resolved absorption spectroscopy. The C−O bond cleavage of the benzopyrans (closed forms) occurs via the first excited singlet state within 2 ps to produce vibrationally ex…
Die eindeutige Zuordnung der 3 dσ*→4 pσ-Metall-Metall-Übergänge anhand spektroskopischer und struktureller Untersuchungen belegt die Existenz cuprophiler CuI⋅⋅⋅CuI-Wechselwirkungen in diskreten zweikernigen, Diphosphan-verbrückten CuI-Komplexen (siehe Bild). Die an den CuI-Zentren beobachtete Lumineszenz hängt in erst…
Nanotube fibers are expected to have a wide range of applications from energy storage to high-strength mechanical devices. But as Baughman explains in his Perspective, methods for making such fibers have been of limited success. In contrast, the process reported by Vigolo et al. shows great promise. Together with a re…
The highest number, so far, of well-resolved, completely reversible reduction waves of a molecular compound is found during the stepwise reduction of the tetranuclear [2×2] Co grid-type complex 1 (R=Ph) by a total of 11 electrons. The associated (differential) cyclic voltammogram (see picture) shows ten reduction wave…
Hohe Quantenausbeuten liefert der Metallocorrol-Prototyp 1, der problemlos aus GaCl3 und Tris(pentafluorphenyl)corrol hergestellt wurde. Die Kristall- und Elektronenstruktur von 1, die Bildung des π-kationischen Radikalkomplexes durch chemische Oxidation und die charakteristischen spektroskopischen Eigenschaften des I…
Was Porphyrine können, können Corrole schon lange! Die einfache Synthese des verhältnismäßig stabilen, spektroskopisch charakterisierten Oxomangan(V)-Corrols 2 gelang aus [Mn(tpfc)] 1 (H3(tpfc)=5,10,15-Tris(pentafluorphenyl)corrol), einem milden Katalysator für die Epoxidierung von Styrol mit Iodosylbenzol.
The miscibility of polypropylene (PP) melts in which the chains differ only in stereochemical composition has been investigated by two different procedures. One approach used detailed local information from a Monte Carlo simulation of a single chain, and the other approach takes this information from a rotational isom…
Vanadium-haltige Polyoxometallate wie PV2Mo10O40 wirken bei der katalysierten Oxygenierung von Kohlenwasserstoffen in homogener Flüssigphase als Sauerstoffüberträger [Gl. (1) und (2)]. Der Verlauf der Reaktion lässt sich mit einem Mars-van Krevelen-Mechanismus beschreiben.
The tripodal ligand tris[(3-hydroxy-1-methyl-2-oxo-1,2- didehydropyridine-4-carboxamido)ethyl]amine (TREN-Me-3,2-HOPO) forms a stable Gd3+ complex that is a promising candidate as a magnetic resonance imaging (MRI) contrast agent. However, its low water solubility prevents detailed magnetic characterization and practi…
Part 1 Review of composite materials: Overview Fundamentals of composites. Part 2 Fundamentals of finite element analysis. Part 3 Finite elements applied to composite materials: Composites and finite element analysis Definition of composite materials in finite element analysis. Part 4 Analytical and numerical modellin…