O2‐mediated dehydrogenative amination of phenols

A method was developed for the direct dehydrogenative construction of C? N bonds between unprotected phenols and a series of cyclic anilines without resorting to any kind of metal activation of either substrate and without the use of halides. The resulting process relies on the exclusively organic activation of molecular oxygen and the subsequent oxidation of the aniline substrate. This allows the coupling of ubiquitous phenols, thus furnishing aminophenols through an atom‐economical and most sustainable dehydrogenative amination method. This new reactivity, which relies on the intrinsic organic reactivity of cumene in what can be seen as a modified Hock activation process of oxygen, is expected to have a large impact on the formation of C? N bonds in organic synthesis.     

Fluorescent In Situ Targeting Probes for Rapid Imaging of Ovarian‐Cancer‐Specific γ‐Glutamyltranspeptidase

γ‐Glutamyltranspeptidase (GGT) is a tumor biomarker that selectively catalyzes the cleavage of glutamate overexpressed on the plasma membrane of tumor cells. Here, we developed two novel fluorescent in situ targeting (FIST) probes that specifically target GGT in tumor cells, which comprise 1) a GGT‐specific substrate unit (GSH), and 2) a boron–dipyrromethene (BODIPY) moiety for fluorescent signalling. In the presence of GGT, sulfur‐substituted BODIPY was converted to amino‐substituted BODIPY, resulting in dramatic fluorescence variations. By exploiting this enzyme‐triggered photophysical property, we employed these FIST probes to monitor the GGT activity in living cells, which showed remarkable differentiation between ovarian cancer cells and normal cells. These probes represent two first‐generation chemodosimeters featuring enzyme‐mediated rapid, irreversible aromatic hydrocarbon transfer between the sulfur and nitrogen atoms accompanied by switching of photophysical properties.     

Barium‐Mediated Cross‐Dehydrocoupling of Hydrosilanes with Amines: A Theoretical and Experimental Approach

Alkaline‐earth (most prominently barium) complexes of the type [Ae{N(SiMe₃)₂}₂?(THF)_x] and [{N^N}Ae{N(SiMe₃)₂}?(THF)_x] are very active and productive precatalysts (TON=396, TOF up to 3600 h^?1; Ca相似文献   

Boron‐Containing Polycyclic Aromatic Hydrocarbons: Facile Synthesis of Stable,Redox‐Active Luminophores

Herein we show that replacing the two meso carbon atoms of the polycyclic aromatic hydrocarbon (PAH) bisanthene by boron atoms transforms a near‐infrared dye into an efficient blue luminophore. This observation impressively illustrates the impact of boron doping on the frontier orbitals of PAHs. To take full advantage of this tool for the targeted design of organic electronic materials, the underlying structure–property relationships need to be further elucidated. We therefore developed a modular synthesis sequence based on a Peterson olefination, a stilbene‐type photocyclization, and an Si–B exchange reaction to substantially broaden the palette of accessible polycyclic aromatic organoboranes and to permit a direct comparison with their PAH congeners.     

The Transition States for CO2 Capture by Substituted Ethanolamines

Quantum chemical studies are used to understand the electronic and steric effects on the mechanisms of the reaction of substituted ethanolamines with CO₂. SCS‐MP2/6‐311+G(2d,2p) calculations are used to obtain the activation energy barriers and reaction energies for both the carbamate and bicarbonate formation. Implicit solvent effects are included with the universal solvation model SMD. Carbamate formation is more favorable than bicarbonate formation for monoethanolamine (MEA) both kinetically and thermodynamically. Increase of the steric hindrance on the C atoms around the N atom in substituted ethanolamines favors bicarbonate formation over carbamate formation with lower activation barriers and thereby higher reaction rates. In contrast, substitution by an N‐methyl or N‐ethyl group on MEA leads to a lower activation barrier for both carbamate formation and bicarbonate formation. As a result, higher reaction rates are expected as compared to MEA, and therefore these compounds have significant potential as industrial CO₂ capturing solvents.     

The Mediterranean aromatic plants and their culinary use.

Over the centuries, aromatic plants have acquired both practical relevance and socio-cultural meanings that have influenced the evolution of humanity itself and created relevant economic value. In fact, since a long time ago spices were promoted to a leading economic role, and their profitability has been often comparable to that of other commodities traded in much larger volumes. Many geographical discoveries, explorations, worldwide relationships between populations in different continents, were undertaken in order to meet the quest for new flavours, new tastes, new medicinal plants or to find new markets for those already known. While the use of plants in medicine offers an extensive written documentation produced by most ancient human civilizations, the same can not be said for food herbs and flavouring spices. However, without the adequate selection of edible, reliable and valuable plants from the whole biodiversity pool operated by folk cultures everywhere in the world, their proper combination would have never been elaborated and cuisines, like the Mediterranean ones, would have not attained such unique mix of flavour, taste and nutrient content that has no equal in the world. Therefore, any consideration on herbs and aromatic plants in the kitchen leads inequivocally to a journey into tradition.     

Development of a magnetic solid‐phase extraction coupled with high‐performance liquid chromatography method for the analysis of polyaromatic hydrocarbons

A novel magnetic solid phase extraction coupled with high‐performance liquid chromatography method was established to analyze polyaromatic hydrocarbons in environmental water samples. The extraction conditions, including the amount of extraction agent, extraction time, pH and the surface structure of the magnetic extraction agent, were optimized. The results showed that the amount of extraction agent and extraction time significantly influenced the extraction performance. The increase in the specific surface area, the enlargement of pore size, and the reduction of particle size could enhance the extraction performance of the magnetic microsphere. The optimized magnetic extraction agent possessed a high surface area of 1311 m²/g, a large pore size of 6–9 nm, and a small particle size of 6–9 μm. The limit of detection for phenanthrene and benzo[g,h,i]perylene in the developed analysis method was 3.2 and 10.5 ng/L, respectively. When applied to river water samples, the spiked recovery of phenanthrene and benzo[g,h,i]perylene ranged from 89.5–98.6% and 82.9–89.1%, respectively. Phenanthrene was detected over a concentration range of 89–117 ng/L in three water samples withdrawn from the midstream of the Huai River, and benzo[g,h,i]perylene was below the detection limit.     

分光光度法测定亚甲基蓝溶液浓度线上实验设计

基于朗伯-比尔定律与互补色原理,利用QQ截图读取色块RGB三原色组成的功能,获得不同亚甲基蓝浓度色阶对应的红色和绿色信号,设计了亚甲基蓝测定的简易紫外-可见分光光度法实验方案。该方案包括标准色阶制作、颜色信号读取、标准曲线绘制,以及待测样品测试等。通过学生实验,获得了满意的可靠性。该实验方案尤其适用于线上教学或缺少分光光度计的线下教学。     

高中“化学反应与电能”跨学科项目式教学*——探究原电池电动势的影响因素

以“探究原电池电动势的影响因素”为项目学习主题,以探讨化学电源的应用、探究原电池的工作原理、测量原电池的电动势、搭建高电动势原电池等4个任务为关键项目任务,呈现高中“化学反应与电能”跨学科项目式教学设计思路和教学实践过程。