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Vargas Carrillo posted an update 6 months ago
A family of helical dinuclear copper(i) pyridylphospholane complexes X (X = BF4-, Cl- and Br-) was prepared. The family includes the first examples of this type of complex based on copper(i) chloride and copper(i) bromide. The two isomers typical of this class of compounds, namely head-to-head and head-to-tail complexes, were studied in solution by spectroscopic and optical methods, and in the solid state by X-ray diffraction. Furthermore, the solid-state luminescence of the complexes at different temperatures was studied, and the results were interpreted using quantum-chemical calculations. It was shown that the luminescence of the complexes is attributed to the 3(M + X)LCT transitions.Polyphenolic antioxidants may effectively reduce acrylamide contents in processed foods. However, few studies focused on their detoxification effects via estimating the profile change of internal exposure biomarkers. Here we showed the protective effect of a water-soluble flavone-C-glycoside-rich antioxidant from bamboo leaves (AOB-w) against acrylamide-induced toxicity in college students. The participants were randomly assigned to either the AOB-w or control group and served potato chips, corresponding to 12.6 μg per kg·bw of dietary exposure to acrylamide, followed by capsules containing 350 mg AOB-w or equivalent placebo. The kinetics of acrylamide, glycidamide, and mercapturic acid metabolites was profiled, and their hemoglobin adducts were measured. The toxicokinetic study showed that AOB-w promoted the excretion of acrylamide and shortened the distribution but prolonged the excretion of N-acetyl-S-(2-carbamoylethyl)-l-cysteine (AAMA) and N-acetyl-S-(2-carbamoyl-2-hydroxyethyl)-l-cysteine. The intervention with AOB-w reduced the peak concentration and area under curve of AAMA by 42.1% and 49.8%, respectively. Besides, AOB-w gender-dependently altered the toxicokinetic profile and reduced the amount of a human-specific urinary biomarker, N-acetyl-S-(2-carbamoylethyl)-l-cysteine-sulfoxide in women. AOB-w accelerated the metabolism of hemoglobin adducts of acrylamide and glycidamide in blood of women. Compared with the baseline levels on the beginning day, we observed a significant enhancement of hemoglobin adducts on the 10th day after serving them potato chips, showing 54.5% and 20.9% higher levels of the hemoglobin adducts of acrylamide and glycidamide, respectively, which thus indicated a lower level of glycidamide-to-acrylamide ratio in blood of participants. Overall AOB-w could effectively reduce the internal exposure to acrylamide in college students, which provides advanced insights into protective functions of natural antioxidants against in vivo toxicity of chemical contaminants from diet.The McLafferty rearrangement is a well-known process in mass spectrometry. In ionization of organic molecules containing a carbonyl group, β cleavage occurs following transfer of a hydrogen atom of aliphatic CH at the γ position to the carbonyl group. Although the McLafferty rearrangement has undergone numerous mass spectrometric investigations, no spectroscopic investigation of the enolized radical cation generated in the hydrogen atom transfer has been carried out. 2-Pentanone is the simplest ketone containing CH bonds at the γ position. In this study, infrared predissociation spectroscopy for both neutral and ionized 2-pentanone in the gas phase through vacuum ultraviolet ionization detection is performed to investigate the ionization-induced isomerization and to observe the enolized product. An OH stretch band is observed in the infrared spectrum of ionized 2-pentanone, and this demonstrates its enolization accompanying the rearrangement of an alkyl hydrogen. The enolization of ionized 2-pentanone is theoretically supported by the reaction path search based on the anharmonic downward distortion following method.Hydrogen production from electrocatalytic water splitting in electrolyzers is a key process to store excess electric energy produced from intermittent renewable energy sources. For proton exchange membrane (PEM) electrolyzers, carbon supported platinum particles exhibit the highest rates for the hydrogen evolution reaction (HER); however, high Pt costs limit the wide spread use of this technology. By employing a graphene layer grown on a Ru(0001) single crystal as a template for Pt nanocluster (NC) growth, we studied the dependence of the HER activity on the NC size using NCs of different sizes. We provide clear quantitative experimental evidence for a volcano-like relationship between the HER activity and the NC size which has been missing so far. For Pt NCs with very low sizes below 2 nm, we found stunningly improved exchange HER current densities. The highest exchange current density was observed for Pt NCs with an average size of ca. 38 atoms. These Pt38 NCs do not only surpass the Pt-mass-specific activity of commercial Pt electrode materials by well above three orders of magnitude, also their exchange current density is located close to the maximum exchange current density for the HER predicted theoretically for transition metal surfaces. The present work provides a strong stimulus for future research towards technically feasible Pt NC catalysts with cluster sizes in the range of few tens of Pt atoms.A novel reactivity-triggering strategy for inert organic molecules was developed via the chemical properties of a crystal-solution interface. Upon self-assembling to form a 002 crystal interface, inactive 9-anthracene boric acid was transformed into an ultra-high active state, triggering a catalyst-free, environmentally benign, aromatic substitution and oxidation reaction, which achieved 99% yield in 1 h under ambient conditions.The properties of adamantane render it an attractive building block towards the synthesis of robust frameworks. This work describes the synthesis of the L-shaped 1,3-bis(3′-carboxypyridine)adamantane (L1) ligand and the corresponding Li(i), Zn(ii) and Cu(ii) frameworks. Three topologically analogous Li(i) frameworks LiMOF12, LiMOF30 and LiMOF50 are reported, with calculated solvent accessible void volumes of 46, 43 and 36%, respectively. Nanchangmycin The reaction between the carboxylate groups of L1 and the Li(i) cations resulted in the formation of Li-carboxylate rods. The Li-carboxylate rods contributed to the formation of a double-walled MOF with large, open one dimensional channels. The synergistic effect of the double wall, lithium-carboxylate rods and the adamantane core itself, resulted in the formation of a robust network stable up to temperatures of 300-350 °C and a minimum of three months stability in air. Furthermore, complexation of L1 with Cu(BF4)2·H2O and Zn(CF3SO3)2 provided a 2D → 3D interpenetrated network containing a classic dimeric copper paddle-wheel SBU, and an infinite 1D chain which extended into a 3D structure facilitated by hydrogen-bonding interactions, respectively.
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