Reactions of RSe− (R = Me,Ph) Groups in [RSeFe(CO)4I and [RSeCr(CO)5−]

The anionic [MeSeFe(CO)₄] and [MeSeCr(CO)₅] complexes were synthesized by reaction of [PPN][HFe(CO)₄] and [PPN][HCr(CO)₅] with MeSeSeMe respectively via nucleophilic cleavage of the Se-Se bond. The ease of cleavage of the Se-Se bond follows the nucleophilic strength of metal-hydride complexes. Methylation of [RSeCr(CO)₅^?] by the soft alkylating agent MeI resulted in the formation of neutral (MeSeMe)Cr(CO)₅ in THF at 0°C. In contrast, the [ICr(CO)₅^?] was isolated at ambient temperature. Reaction of [MeSeFe(CO)₄^?] or [MeSeCr(CO)₅^?] with HBF₄ yielded (CO)₃Fc(μ-SeMe)₂Fe(CO)₃ dimer and anionic [(CO )₅Cr (μ-SeMe)Cr(CO)₅^?] respectively, and no neutral (HSeMe)Fe(CO)₄ and (HSeMe)Cr(CO)₅ were detected spectrally (IR) even at low temperature. Reaction of NOBF₄ or [Ph₃C][BF₄] and [MeSeCr(CO)₅^?] resulted in the neutral monodentate (MeSeSeMe)Cr(CO)₅ complex. Addition of 1 equiv CpFe(CO)₂I to 2 equiv [MeSeCr(CO)₅^?] gave CpFe(CO)₂(SeMe) and the anionic [(CO)₅Cr(μ-SeMe)Cr(CO)₅^?] in THF at ambient temperature.     

离子注入修饰电极检测硝基苯

离子注入是一种新技术，可按人们的意愿和需要，将不同的离子注入不同的基本电极表面，制成具有催化活性强，稳定性高，重现性好等特点的修饰电极。作者研究了离子注入钴和注入镍的玻碳电极在０．１ｍｏｌ／ＬＨＡｃ－ＮａＡｃ缓冲溶液中硝基苯的行为及测定。     

ChemInform Abstract: Aromatic Metal‐Centered Monocyclic Boron Rings: Co@B‐8 and Ru@B‐9.

Co@B^‐₈, Ru@B^‐₉, Co@B₈, and Ru@B₉ clusters are characterized by photoelectron spectroscopy and DFT calculations.     

Enhancements of rate capability and cyclic performance of spinel LiNi0.5Mn1.5O4 by trace Ru-doping

The rate capability and cyclic performance of the LiNi_0.5Mn_1.5O₄ under high current density have been significantly improved by doping a small amount of ruthenium (Ru). Specifically, Li_1.1Ni_0.35Ru_0.05Mn_1.5O₄ and LiNi_0.4Ru_0.05Mn_1.5O₄ synthesized by solid state reaction can respectively deliver a discharge capacity of 108 and 117 mAh g^?1 at 10 C rate between 3 and 5 V. At 10 C charge/discharge rate, Li_1.1Ni_0.35Ru_0.05Mn_1.5O₄ and LiNi_0.4Ru_0.05Mn_1.5O₄ can respectively maintain 91% and 84% of their initial capacity after 500 cycles, demonstrating that Ru-doping could be a way to enhance the electrochemical performance of spinel LiNi_0.5Mn_1.5O₄.     

Electrophoretic deposition of titanate nanotube films with extremely large wetting contrast

A facile electrophoretic deposition (EPD) process has been developed to prepare thin films consisting of titanate nanotubes (TNTs) that were synthesized by a hydrothermal approach. Such an EPD process offers easy control in the film thickness and the adhesion to the substrate was found to be strong. The chemical composition and structure of the products have been characterized by XRD, HRTEM, and FESEM. It was found that the functionalization of TNTs plays a key role on the electrolyte stability and the formation of a uniform TNT film with good adhesion. The as-prepared TNT films show exceptional superhydrophilic behavior with ultra-fast spreading, while it converts to superhydrophobicity yet with strong adhesion after 1H,1H,2H,2H-perfluorooctyl-triethoxysilane modification. This study provides an interesting method to prepare films with extremely high wettability contrast that are useful for producing different types of functional materials.     

Multiple reaction monitoring-based determination of bovine α-lactalbumin in infant formulas and whey protein concentrates by ultra-high performance liquid chromatography–tandem mass spectrometry using tryptic signature peptides and synthetic peptide standards

The determination of α-lactalbumin in various dairy products attracts wide attention in multidiscipline fields because of its nutritional and biological functions. In the present study, we quantified the bovine α-lactalbumin in various infant formulas and whey protein concentrates using ultra-high performance liquid chromatography coupled to tandem mass spectrometer in multiple reaction monitoring mode. Bovine α-lactalbumin was quantified by employing the synthetic internal standard based on the molar equivalent relationship among the internal standard, bovine α-lactalbumin and their signature peptides. This study especially focused on the recovery rates of the sample preparation procedure and robust quantification of total bovine α-lactalbumin in its native and thermally denatured form with a synthetic internal standard KILDKVGINNYWLAHKALCSE. The observed recovery rates of bovine α-lactalbumin ranged from 95.8 to 100.6% and the reproducibility was excellent (RSD < 6%) at different spiking levels. The limit of quantitation is 10 mg/100 g for infant formulas and whey protein concentrates. In order to validate the applicability of the method, 21 brands of infant formulas were analyzed. The acquired contents of bovine α-lactalbumin were 0.67–1.84 g/100 g in these infant formulas in agreement with their label claimed values. The experiment of heat treatment time showed that the loss of native α-lactalbumin enhanced with an increasing intensity of heat treatment. Comparing with Ren's previous method by analysis of only native bovine α-lactalbumin, the present method at the peptide level proved to be highly suitable for measuring bovine α-lactalbumin in infant formulas and whey protein concentrates, avoiding forgoing the thermally induced denatured α-lactalbumin caused by the technological processing.     

Poly(l-glutamic acid)-based star-block copolymers as pH-responsive nanocarriers for cationic drugs

Star-block copolymers PEI-g-(PLG-b-PEG), which consist of a hyperbranched polyethylenimine (PEI) core, a poly(l-glutamic acid) (PLG) inner shell, and a poly(ethylene glycol) (PEG) outer shell, were synthesised and evaluated as nanocarriers for cationic drugs. The synthesised star-block copolymers were characterised by ¹H NMR, gel permeation chromatography (GPC), dynamic light scattering (DLS), and transmission electron microscopy (TEM). Crystal violet (CV), as a model cationic dye, and doxorubicin hydrochloride (DOX), as a model anticancer drug, could be efficiently entrapped by the synthesised star-block copolymers at physiological pH as a result of electrostatic interactions between the cationic guest molecules and the negatively charged PLG segments in the PEI-g-(PLG-b-PEG) host. The drug–polymer complexes showed relatively high temporal stability at physiological pH and sustained release of the encapsulated drugs was observed. The entrapped model compounds demonstrated accelerated release as the pH was gradually decreased.