10,000 publications from this institution
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
Abstract The formation of flexible self‐assembled monolayers (SAMs) in which an external trigger modifies the geometry of surface‐anchored molecules is essential for the development of functional materials with tunable properties. In this work, it is demonstrated that NO 2 ‐functionalized N‐heterocyclic carbene molecules (NHCs), which were anchored on Au (111) surface, change their orientation from tilted into flat‐lying position following trigger‐induced reduction of their nitro groups. DFT calculations identified that the energetic driving force for reorientation was the lower steric hindrance and stronger interactions between the chemically reduced NHCs and the Au surface. The trigger‐induced changes in the NHCs′ anchoring geometry and chemical functionality modified the work function and the hydrophobicity of the NHC‐decorated Au surface, demonstrating the impact of a chemically tunable NHC‐based SAM on the properties of the metal surface.
ZACKAY et al.1 have discussed the increase in fracture toughness of untempered ultra-high strength steels resulting from the use of high austenizing temperatures for solution treatment. Their results indicate that the toughness is increased suddenly and dramatically, by a factor of more than two, when the steels are austenized at temperatures greater than 1,100° C (Fig. 1). The effect is promoted by fast quenching rates. They show further that a two-step quenching procedure from high austenizing temperatures (for example, 1,200° C→870° C→quench) can eliminate any danger of quench cracking, whilst causing only a small (7%) reduction in fracture toughness. This improvement in toughness, obtained by using high austenizing temperatures, was attributed to the retardation of grain boundary nucleation of a second phase when high energy grain boundaries, associated with small grains, are eliminated by grain growth.
I am grateful to my four critics for taking kindly to my intrusion into the social science of race and human brutality in history and for responding to my sketch of “The Checkerboard of Ethnoracial Violence” (Wacquant 2023a) with earnest and productive comments. In the spirit of their articles, I will rejoin to their propositions and then enroll them to suggest further pathways to a better understanding of the specificity and historicity of racialized violence, individual and collective.
We present a physical implementation of the twist-and-flip circuit containing a nonlinear gyrator. Many phase portraits and their associated Poincare maps are observed experimentally from this circuit and presented in this paper.
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Aryl tosylates are attractive substrates for Pd-catalyzed cross-coupling reactions, but they are much less reactive than the more commonly used aryl triflates. We report the oxidative addition of aryl tosylates to Pd(PPF-t-Bu)[P(o-tolyl)3] and to Pd(CyPF-t-Bu)[P(o-tolyl)3] at room temperature to produce the corresponding palladium(II) aryl tosylate complexes. In the presence of added bromide ions, arylpalladium(II) bromide complexes were formed. The rate of oxidative addition was accelerated by addition of either coordinating or weakly coordinating anions, and the reactions were faster in more polar solvents. The mild conditions for oxidative addition allowed for the development of Pd-catalyzed Kumada couplings and amination reactions of unactivated aryl tosylates at room temperature. The catalysts for these mild couplings of aryl tosylates were generated from palladium precursors and the sterically hindered Josiphos-type ligands that induced oxidative addition of aryl tosylates to Pd(0) at room temperature.
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
The surface composition of the H2SO4/H2O binary system in the temperature range (298−170 K) has been studied using differentially pumped Auger electron and X-ray photoelectron spectrometers designed to perform under equilibrium conditions (PH2O ≈ 10-6−10-4 Torr). Both spectroscopies have been calibrated on pure sulfuric acid solutions to illustrate their ability to provide accurate atomic stoichiometries within the near-surface region. In the case of AES this ability has also been extended as a tool for the study of the surface composition in the H2SO4/H2O binary system under equilibrium conditions. Compositional analysis of this acidified surface indicates that under these experimental conditions the chemical compositions of the bulk and near-surface region are equal within experimental error. Mass spectrometric analysis of the vapor composition indicates equilibration between the acid solution and D2O.
A mixed potential model (MPM) has been developed for calculating electrochemical potential (ECP) data for boiling water reactor (BWR) in-vessel components and recirculation piping using compositional data obtained from radiolysis water chemistry models. The calculated core component ECPs for the Duane-Arnold BWR are in good agreement with limited in-plant data. The calculated ECP data suggest that hydrogen water chemistry (HWC) will be effective in protecting the core inlet and the recirculation system of Duane-Arnold against intergranular stress corrosion cracking (IGSCC) but that it may not be effective for this purpose in Dresden-2 because of the higher concentrations of radiolysis products (notable O2 and H2O2) predicted to exist in this reactor. Furthermore, the MPM predicts that HWC will be ineffective in protecting various in-vessel components such as the upper plenum, fuel channels, core bypass structure, and the downcomer. Electrocatalysis of the redox reactions shows promise as a means of enhancing the effectiveness of HWC, and it is also predicted to be viable under NWC conditions provided that hydrogen oxidation alone can be catalyzed. However, in this case, the exchange current density for hydrogen oxidation must be enhanced by a factor in excess of 104 for protection to be achieved.
