Rolf Huisgen explored the Diels‐Alder reactions of 1,3,5‐cycloheptatriene (CHT) and cyclooctatetraene (COT) with dienophiles maleic anhydride and 4‐phenyl‐1,2,4‐triazoline‐3,5‐dione (PTAD) to determine the kinetics and mechanisms of various electrocyclizations and Diels‐Alder reactions. These reactions have been examined with density functional theory. Modern computational chemistry has provided information not previously available by experiment. Transition states for all the reactions have been...
Tue May 05, 2020 22:57
Chemical warfare agents (CWAs) and more specifically, organophosphorous nerve agents, are some of the most acutely toxic chemicals to humans. Despite international treaties designed to ban nerve agents, they continually resurface to cause harm to both civilian and military personnel worldwide. Herein, we report the synthesis of a UiO‐66‐NCS MOF from postsynthetic modification (PSM) of UiO‐ 66‐NH 2 . The UiO‐66‐NCS MOF displays a ~20‐fold increase in activity against the chemical warfare agent simulant...
Tue May 05, 2020 22:54
Attempted preparation of a chelated Co(II) β ‐silylamide resulted in the unprecedented disproportionation to Co(0) and a spirocyclic cobalt(IV) bis( β ‐silyldiamide): [Co[(N t Bu) 2 SiMe 2 ] 2 ] ( 1 ). Compound 1 exhibits a room temperature magnetic moment of 1.8 B.M and a solid state axial EPR spectrum diagnostic of a rare S = 1 / 2 configuration for tetrahedral Co(IV). Semicanonical coupled‐cluster calculations (DLPNO‐CCSD(T)) revealed the doublet state was clearly preferred...
Tue May 05, 2020 22:00
Hypervalent Fe V =O species are implicated in a multitude of oxidative reactions of organic substrates, as well as in catalytic water oxidation, a reaction crucial for artificial photosynthesis. Spectroscopically characterized Fe V species are exceedingly rare and, so far, were produced by the oxidation of Fe complexes with peroxy acids or H 2 O 2 : reactions that entail breaking of the O‐O bond to form a Fe V =O fragment. The key Fe V =O species proposed to initiate the O‐O bond formation...
Tue May 05, 2020 18:59
We report a photochemical flow setup that exploits λ‐orthogonal reactions using two different colours of light (λ 1 = 350 nm and λ 2 = 410 nm) in sequential on‐line irradiation steps. Critically, both photochemically reactive units (a visible light reactive chalcone and a UV‐activated photo‐caged diene) are present in the reaction mixture. We demonstrate the power of two colour photoflow by the wavelength‐selective end group modification of photo‐caged polymer end groups and the subsequent polymer...
Tue May 05, 2020 18:14
Herein, the universal design of high‐efficiency stimuli‐responsive luminous materials endowed with mechanochromic luminescence (MCL) and thermally activated delayed fluorescence (TADF) functions is reported. The origin of the unique stimuli‐triggered TADF switching for a series of carbazole–isophthalonitrile‐based donor–acceptor (D–A) luminogens is demonstrated based on systematic photophysical and X‐ray analyses, coupled with theoretical calculations. It was revealed that a tiny alteration of the...
Tue May 05, 2020 16:24
The generation of carbon‐centered radicals from air‐sensitive organoboron compounds via nucleohomolytic substitution at boron is one of the most general methods to generate non‐functionalized and functionalized radicals. Due to their reduced Lewis acidity, the very popular, air‐stable, and readily available alkylboronic pinacol esters are not suitable substrates for this process. Herein, is reported their in situ conversion to alkylboronic catechol esters by boron‐transesterification with a substoichiometric...
Tue May 05, 2020 15:54
Aromatic organic compounds can be used as electrode materials in rechargeable batteries and are expected to advance the development of both anode and cathode materials for sodium‐ion batteries (SIBs). However, most aromatic organic compounds assessed as anode materials in SIBs to date exhibit significant degradation issues under fast‐charge/discharge conditions and unsatisfying long‐term cycling performance. Here we present a molecular design concept for improving the stability of organic compounds...
Tue May 05, 2020 15:24
Superwetting membranes with responsive property have attracted heightened attention because of their fine‐tunable surface wettability. However, their functional diversity is severely limited by the “black‐or‐white” wettability transition. Here, we develop a coating strategy to fabricate the multifunctional responsive superwetting membranes with SiO2/octadecylamine patterns. The adjustable patterns relating to the responsive region are the key factor for functional diversity. Specifically, the coated...
Tue May 05, 2020 12:54
A general strategy for visible‐light‐enabled site‐selective trifluoromethylative pyridylation of unactivated alkenes has been developed using pyridines and triflic anhydride (Tf 2 O). Intriguingly, the N‐triflylpyridinium salts generated in situ from pyridines and Tf 2 O, serve as effective modular bifunctional reagents to install both CF 3 and pyridyl group to various olefins while controlling C4‐selectivity in radical addition to the pyridine core. This synthetic route exhibited broad substrate...
Tue May 05, 2020 12:29
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