Interplay between disorder and electronic correlations in compositionally complex alloys.

Owing to their exceptional mechanical, electronic, and phononic transport properties, compositionally complex alloys, including high-entropy alloys, represent an important class of materials. However, the interplay between chemical disorder and electronic correlations, and its influence on electronic structure-derived properties, remains largely unexplored. This is addressed for the archetypal CrMnFeCoNi alloy using resonant and valence band photoemission spectroscopy, electrical resistivity, and optical conductivity measurements, complemented by linear response calculations based on density functional theory.

High-Pressure Synthesis of Rare-Earth Borate-Nitrate Crystals for Second Harmonic Generation.

The crystals of a novel family of rare-earth borate-nitrate compounds, (BO)(NO)NO ( = Pr, Nd), were grown at high-pressure in KAs flux and their crystal structure was determined. The new type of the crystalline structure consists of parallel chains of octahedra connected by common faces and forming the channels with the NO triangular planar motifs in the center, and isolated O tetrahedra separated from each other by N triangular motifs. Each NO triangle is in fact a part of rather unusual (NBO) block consisting of 3 distorted BO tetrahedra around central nitrogen atom.

New refinement of the crystal structure of Zn(NH)Cl at 100 K.

The crystal structure of [ZnCl(NH)], diamminedi-chlorido-zinc, was re-investigated at low temperature, revealing the positions of the hydrogen atoms and thus a deeper insight into the hydrogen-bonding scheme in the crystal packing. In comparison with previous crystal structure determinations [MacGillavry & Bijvoet (1936 ▸). , 249-255; Yamaguchi & Lindqvist (1981 ▸).

Chiral Discrimination in Rhodium(I) Catalysis by 2,5-Disubstituted 1,3,4,6-Tetrahydropenatalene Ligands-More Than Just a Twist of the Olefins?

Chiral dienes are useful ligands in a number of asymmetric transition-metal-catalyzed reactions. Here, we evaluate the efficiency of 2,5-disubstituted 1,3,4,6-tetrahydropentalenes as ligands to rhodium(I). 2,5-Dibenzyl and diphenyl tetrahydropentalenes were synthesized in two steps and resolved, either chromatographically, or through fractional crystallization of diastereomeric rhodium(I) salts.

Control of Enantioselectivity in Rhodium(I) Catalysis by Planar Chiral Dibenzo[a,e]cyclooctatetraenes.

Planar chiral 5,11-disubstiuted dibenzo[a,e]cyclo-octatetraenes (dbCOTs) have been developed as the first useful chiral homologs to dbCOT-ligands for asymmetric applications. Methods enabling the preparation of such compounds on a gram-scale in enantiomerically pure form are described. Evaluated as ligands in rhodium(I)-catalyzed 1,4- and 1,2-arylation reactions, tertiary and quarternary stereogenic centers were formed with excellent yields and selectivities of up to >99 % ee.

Three Sesquiterpenoid Dimers from Chloranthus japonicus: Absolute Configuration of Chlorahololide A and Related Compounds.

A novel sesquiterpenoid dimer, named multistalide C (1), together with two known congeners, shizukaols C (2) and D (3), was isolated from the whole plant of Chloranthus japonicus Sieb. The structures of compounds 1-3 were elucidated by extensive HR-ESI-MS, 1D, and 2D NMR spectroscopic analysis. Compounds 1-3 exhibited significant toxic effects on brine shrimp larvae (Artemia salina).

Milestone in the NTB phase investigation and beyond: direct insight into molecular self-assembly.

Although liquid-crystalline materials are most widely exploited for flat-panel displays, their ability to self-organize into periodically ordered nanostructures gives rise to a broad variety of additional applications. The recently discovered low-temperature nematic phase (N(TB)) with unusual characteristics generated considerable attention within the scientific community: despite the fact that the molecules from which the phase is composed are not chiral, the helicoidal structure of the phase is strongly implicated. Here we report on combined experimental, computational and spectroscopic studies of the structural aspects influencing formation of the N(TB) phase as well as on the molecular organization within the phase.

Effects of geometry and electronic structure on the molecular self-assembly of naphthyl-based dimers.

Three new series of symmetric dimers containing a naphthoyloxybenzyl (NB), benzoyloxynaphthyl (BN), and naphthoyloxysalicyl (NS) mesogenic core linked to an alkylene spacer via an imino group were synthesized. The effects of the variant spacer parity as well as the variant core structure on the mesomorphic properties have been studied. The dimers having NB and BN mesogenic units display intercalated smectic structures regardless of the spacer parity.

Determination of surface potentials from the electrode potentials of a single-crystal electrode.

Determination of surface potentials Psi0 at the metal oxide/aqueous solution interface from measured electrode potentials of a metal oxide single-crystal electrode (SCrE) is described. The proposed method is based on the surface complexation model and evaluates the surface potential at the isoelectric point, i.e.