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971.
Liangliang Liang Wei Yan Xian Qin Xiao Peng Han Feng Yu Wang Ziyu Zhu Lingmei Liu Yu Han Qinghua Xu Junle Qu Xiaogang Liu 《Angewandte Chemie (International ed. in English)》2020,59(2):746-751
Stimulated emission depletion (STED) microscopy enables ultrastructural imaging of biological samples with high spatiotemporal resolution. STED nanoprobes based on fluorescent organosilica nanohybrids featuring sub‐2 nm size and near‐unity quantum yield are presented. The spin–orbit coupling (SOC) of heavy‐atom‐rich organic fluorophores is mitigated through a silane‐molecule‐mediated condensation/dehalogenation process, resulting in bright fluorescent organosilica nanohybrids with multiple emitters in one hybrid nanodot. When harnessed as STED nanoprobes, these fluorescent nanohybrids show intense photoluminescence, high biocompatibility, and long‐term photostability. Taking advantage of the low‐power excitation (0.5 μW), prolonged singlet‐state lifetime, and negligible depletion‐induced re‐excitation, these STED nanohybrids present high depletion efficiency (>96 %), extremely low saturation intensity (0.54 mW, ca. 0.188 MW cm?2), and ultra‐high lateral resolution (ca. λem/28). 相似文献
972.
Bentian Zhang Gengtao Fu Yutao Li Lecheng Liang Nicholas S. Grundish Yawen Tang John B. Goodenough Zhiming Cui 《Angewandte Chemie (International ed. in English)》2020,59(20):7857-7863
Controllable synthesis of atomically ordered intermetallic nanoparticles (NPs) is crucial to obtain superior electrocatalytic performance for fuel cell reactions, but still remains arduous. Herein, we demonstrate a novel and general hydrogel‐freeze drying strategy for the synthesis of reduced graphene oxide (rGO) supported Pt3M (M=Mn, Cr, Fe, Co, etc.) intermetallic NPs (Pt3M/rGO‐HF) with ultrasmall particle size (about 3 nm) and dramatic monodispersity. The formation of hydrogel prevents the aggregation of graphene oxide and significantly promotes their excellent dispersion, while a freeze‐drying can retain the hydrogel derived three‐dimensionally (3D) porous structure and immobilize the metal precursors with defined atomic ratio on GO support during solvent sublimation, which is not afforded by traditional oven drying. The subsequent annealing process produces rGO supported ultrasmall ordered Pt3M intermetallic NPs (≈3 nm) due to confinement effect of 3D porous structure. Such Pt3M intermetallic NPs exhibit the smallest particle size among the reported ordered Pt‐based intermetallic catalysts. A detailed study of the synthesis of ordered intermetallic Pt3Mn/rGO catalyst is provided as an example of a generally applicable method. This study provides an economical and scalable route for the controlled synthesis of Pt‐based intermetallic catalysts, which can pave a way for the commercialization of fuel cell technologies. 相似文献
973.
Jie Li Shuanglin Qu Wanxiang Zhao 《Angewandte Chemie (International ed. in English)》2020,59(6):2360-2364
A rhodium‐catalyzed remote C(sp3)?H borylation of silyl enol ethers (SEEs, E/Z mixtures) by alkene isomerization and hydroboration is reported. The reaction exhibits mild reaction conditions and excellent functional‐group tolerance. This method is compatible with an array of SEEs, including linear and branched SEEs derived from aldehydes and ketones, and provides direct access to a broad range of structurally diverse 1,n‐borylethers in excellent regioselectivities and good yields. These compounds are precursors to various valuable chemicals, such as 1,n‐diols and aminoalcohols. 相似文献
974.
Russian Journal of Organic Chemistry - A mild and efficient B(C6F5)3-catalyzed conjugate addition of N, N-dialkylanilines to aromatic nitroalkenes is reported. The catalyst shows excellent... 相似文献
975.
Liu Zhimeng Jiang Liang Fu Xiaowei Zhang Junhua Lei Jingxin 《Journal of Thermal Analysis and Calorimetry》2020,140(5):2159-2170
Journal of Thermal Analysis and Calorimetry - In this study, a series of gelators (Gn, n is the number of carbon atoms of used fatty alcohol, n?=?2, 4, 6, 8, 10, 12, 14, 16 and 18) were... 相似文献
976.
Jiang Liang Lei Yuan Liu Qinfeng Wang Yi Zhao Yuanyang Lei Jingxin 《Journal of Thermal Analysis and Calorimetry》2020,139(1):137-146
Journal of Thermal Analysis and Calorimetry - The polyethylene glycol/wood-flour (PEG/WF) composites were synthesized as novel form-stable phase change materials (PCMs) using PEG as phase change... 相似文献
977.
978.
Luzian Porwol Daniel J. Kowalski Alon Henson De‐Liang Long Nicola L. Bell Leroy Cronin 《Angewandte Chemie (International ed. in English)》2020,59(28):11256-11261
We present a chemical discovery robot for the efficient and reliable discovery of supramolecular architectures through the exploration of a huge reaction space exceeding ten billion combinations. The system was designed to search for areas of reactivity found through autonomous selection of the reagent types, amounts, and reaction conditions aiming for combinations that are reactive. The process consists of two parts where reagents are mixed together, choosing from one type of aldehyde, one amine and one azide (from a possible family of two amines, two aldehydes and four azides) with different volumes, ratios, reaction times, and temperatures, whereby the reagents are passed through a copper coil reactor. Next, either cobalt or iron is added, again from a large number of possible quantities. The reactivity was determined by evaluating differences in pH, UV‐Vis, and mass spectra before and after the search was started. The algorithm was focused on the exploration of interesting regions, as defined by the outputs from the sensors, and this led to the discovery of a range of 1‐benzyl‐(1,2,3‐triazol‐4‐yl)‐N‐alkyl‐(2‐pyridinemethanimine) ligands and new complexes: [Fe(L1)2](ClO4)2 ( 1 ); [Fe(L2)2](ClO4)2 ( 2 ); [Co2(L3)2](ClO4)4 ( 3 ); [Fe2(L3)2](ClO4)4 ( 4 ), which were crystallised and their structure confirmed by single‐crystal X‐ray diffraction determination, as well as a range of new supramolecular clusters discovered in solution using high‐resolution mass spectrometry. 相似文献
979.
980.
Jin‐Xia Liang Jian Lin Jingyue Liu Xiaodong Wang Tao Zhang Jun Li 《Angewandte Chemie (International ed. in English)》2020,59(31):12868-12875
Herein, we report a theoretical and experimental study of the water‐gas shift (WGS) reaction on Ir1/FeOx single‐atom catalysts. Water dissociates to OH* on the Ir1 single atom and H* on the first‐neighbour O atom bonded with a Fe site. The adsorbed CO on Ir1 reacts with another adjacent O atom to produce CO2, yielding an oxygen vacancy (Ovac). Then, the formation of H2 becomes feasible due to migration of H from adsorbed OH* toward Ir1 and its subsequent reaction with another H*. The interaction of Ir1 and the second‐neighbouring Fe species demonstrates a new WGS pathway featured by electron transfer at the active site from Fe3+?O???Ir2+?Ovac to Fe2+?Ovac???Ir3+?O with the involvement of Ovac. The redox mechanism for WGS reaction through a dual metal active site (DMAS) is different from the conventional associative mechanism with the formation of formate or carboxyl intermediates. The proposed new reaction mechanism is corroborated by the experimental results with Ir1/FeOx for sequential production of CO2 and H2. 相似文献