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131.
Ya-Hang Wu Prof. Dr. Hongyan Xiao Prof. Dr. Bin Chen Prof. Dr. Richard G. Weiss Prof. Dr. Yu-Zhe Chen Prof. Dr. Chen-Ho Tung Prof. Dr. Li-Zhu Wu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(25):10259-10264
Three rigid and structurally simple heterocyclic stilbene derivatives, (E)-3H,3′H-[1,1′-biisobenzofuranylidene]-3,3′-dione, (E)-3-(3-oxobenzo[c] thiophen-1(3H)-ylidene)isobenzofuran-1(3H)-one, and (E)-3H,3′H-[1,1′-bibenzo[c] thiophenylidene]-3,3′-dione, are found to fluoresce in their neat solid phases, from upper (S2) and lowest (S1) singlet excited states, even at room temperature in air. Photophysical studies, single-crystal structures, and theoretical calculations indicate that large energy gaps between S2 and S1 states (T2 and T1 states) as well as an abundance of intra and intermolecular hydrogen bonds suppress internal conversions of the upper excited states in the solids and make possible the fluorescence from S2 excited states (phosphorescence from T2 excited states). These results, including unprecedented fluorescence quantum yields (2.3–9.6 %) from the S2 states in the neat solids, establish a unique molecular skeleton for achieving multi-colored emissions from upper excited states by “suppressing” Kasha's rule. 相似文献
132.
Xiaokai Ding Dr. Dong Luo Jiaxiang Cui Huixian Xie Dr. Qingqing Ren Prof. Zhan Lin 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(20):7852-7856
Voltage decay and capacity fading are the main challenges for the commercialization of Li-rich Mn-based layered oxides (LLOs). Now, a three-in-one surface treatment is designed via the pyrolysis of urea to improve the voltage and capacity stability of Li1.2Mn0.6Ni0.2O2 (LMNO), by which oxygen vacancies, spinel phase integration, and N-doped carbon nanolayers are synchronously built on the surface of LMNO microspheres. Oxygen vacancies and spinel phase integration suppress irreversible O2 release and help lithium ion diffusion, while N-doped carbon nanolayer mitigates the corrosion of electrolyte with excellent conductivity. The electrochemical performance of LMNO after the treatment improves significantly; the capacity retention rate after 500 cycles at 1 C is still as high as 89.9 % with a very small voltage fading rate of 1.09 mV cycle−1. This three-in-one surface treatment strategy can suppress the voltage decay and capacity fading of LLOs. 相似文献
133.
Dr. Chao Wang Min Hu Dr. Yueying Chu Xue Zhou Dr. Qiang Wang Dr. Guodong Qi Dr. Shenhui Li Prof. Dr. Jun Xu Prof. Dr. Feng Deng 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(18):7265-7269
The understanding of catalyst deactivation represents one of the major challenges for the methanol-to-hydrocarbon (MTH) reaction over acidic zeolites. Here we report the critical role of intermolecular π-interactions in catalyst deactivation in the MTH reaction on zeolites H-SSZ-13 and H-ZSM-5. π-interaction-induced spatial proximities between cyclopentenyl cations and aromatics in the confined channels and/or cages of zeolites are revealed by two-dimensional solid-state NMR spectroscopy. The formation of naphtalene as a precursor to coke species is favored due to the reaction of aromatics with the nearby cyclopentenyl cations and correlates with both acid density and zeolite topology. 相似文献
134.
Shuyuan Zheng Tianwen Zhu Yunzhong Wang Tianjia Yang Prof. Wang Zhang Yuan 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(25):10104-10108
Nonaromatic, cross-conjugated, and highly twisted luminogens consisting of acylated succinimides demonstrate aggregation-induced emission characteristics along with tunable multicolor photoluminescence and afterglows in their single crystals. Effective through-space conjugation among different moieties bearing n/π electrons promote the spin–orbit coupling and intersystem crossing and lead to diverse emissive clusters with concurrently rigidified conformations, thus allowing readily tunable emissions. Derived from it, the proof-of-concept application for advanced anti-counterfeiting is illustrated. These results should spur the rational design of novel nonaromatic AIEgens, and moreover advance understandings of the non-traditional intrinsic luminescence and the origin of tunable multicolor afterglows. 相似文献
135.
Angelina Osipyan Dr. Shabnam Shaabani Robert Warmerdam Dr. Svitlana V. Shishkina Harry Boltz Prof. Dr. Alexander Dömling 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(30):12523-12527
Miniaturization and acceleration of synthetic chemistry is an emerging area in pharmaceutical, agrochemical, and materials research and development. Herein, we describe the synthesis of iminopyrrolidine-2-carboxylic acid derivatives using chiral glutamine, oxo components, and isocyanide building blocks in an unprecedented Ugi-3-component reaction. We used I-DOT, a positive-pressure-based low-volume and non-contact dispensing technology to prepare more than 1000 different derivatives in a fully automated fashion. In general, the reaction is stereoselective, proceeds in good yields, and tolerates a wide variety of functional groups. We exemplify a pipeline of fast and efficient nanomole-scale scouting to millimole-scale synthesis for the discovery of a useful novel reaction with great scope. 相似文献
136.
Prof. Jen-Shyang Ni Tianliang Min Yaxi Li Menglei Zha Dr. Pengfei Zhang Prof. Chun Loong Ho Prof. Kai Li 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(25):10265-10271
Planar luminogens have encountered difficulties in overcoming intrinsic aggregation-caused emission quenching by intermolecular π-π stacking interactions. Although excited-state double-bond reorganization (ESDBR) can guide us on designing planar aggregation-induced emission (AIE) luminogens (AIEgens), its mechanism has yet been elucidated. Major challenges in the field include methods to efficiently restrict ESDBR and enhance AIE performance without using bulky substituents (e.g., tetraphenylethylene and triphenylamine). In this study, we rationally developed fluoro-substituent AIEgens with stronger intermolecular H-bonding interaction for restricted molecular motions and increased crystal density, leading to decreased nonradiative decay rate by one order of magnitude. The adjusted ESDBR properties also show a corresponding response to variation in viscosity. Furthermore, their aggregation-induced reactive oxygen species (ROS) generations have been discovered. The application of such planar AIEgen in treating multidrug-resistant bacteria has been demonstrated in a mouse model. The relationship between ROS generation and distinct E/Z-configurational stacking behaviors have been further understood, providing a design principle for synthesizing planar AIEgen-based photosensitizers. 相似文献
137.
Jiabin Zhang Ding Liu Varma Saikam Madhusudhan R. Gadi Christopher Gibbons Xuan Fu Heliang Song Jin Yu Shukkoor M. Kondengaden Prof. Dr. Peng G. Wang Prof. Dr. Liuqing Wen 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(45):19997-20001
Historically, researchers have put considerable effort into developing automation systems to prepare natural biopolymers such as peptides and oligonucleotides. The availability of such mature systems has significantly advanced the development of natural science. Over the past twenty years, breakthroughs in automated synthesis of oligosaccharides have also been achieved. A machine-driven platform for glycopeptide synthesis by a reconstructed peptide synthesizer is described. The designed platform is based on the use of an amine-functionalized silica resin to facilitate the chemical synthesis of peptides in organic solvent as well as the enzymatic synthesis of glycan epitopes in the aqueous phase in a single reaction vessel. Both syntheses were performed by a peptide synthesizer in a semiautomated manner. 相似文献
138.
Dr. Weihui Ou Dr. Binbin Zhou Junda Shen Dr. Tsz Wing Lo Prof. Dangyuan Lei Dr. Shengliang Li Jing Zhong Prof. Yang Yang Li Prof. Jian Lu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(17):6856-6859
Hot carriers (HCs) and thermal effects, stemming from plasmon decays, are crucial for most plasmonic applications. However, quantifying these two effects remains extremely challenging due to the experimental difficulty in accurately measuring the temperature at reaction sites. Herein, we provide a novel strategy to disentangle HCs from photothermal effects based on the different traits of heat dissipation (long range) and HCs transport (short range), and quantitatively uncover the dominant and potential-dependent role of photothermal effect by investigating the rapid- and slow-response currents in plasmon-mediated electrochemistry at nanostructured Ag electrode. Furthermore, the plasmoelectric surface potential is found to contribute to the rapid-response currents, which is absent in the previous studies. 相似文献
139.
140.
Tobias Ullrich Piermaria Pinter Julian Messelberger Philipp Haines Ramandeep Kaur Jun.-Prof. Dr. Max M. Hansmann Dr. Dominik Munz Prof. Dr. Dirk M. Guldi 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(20):7980-7988
Herein, we present a new class of singlet fission (SF) materials based on diradicaloids of carbene scaffolds, namely cyclic (alkyl)(amino)carbenes (CAACs). Our modular approach allows the tuning of two key SF criteria: the steric factor and the diradical character. In turn, we modified the energy landscapes of excited states in a systematic manner to accommodate the needs for SF. We report the first example of intermolecular SF in solution by dimer self-assembly at cryogenic temperatures. 相似文献