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991.
Shen‐Yi Guo Qing‐Hui Guo Shuo Tong Mei‐Xiang Wang 《Angewandte Chemie (International ed. in English)》2020,59(21):8078-8083
Reported here are the syntheses, conformational structures, electrochemical properties, and noncovalent anion binding of corona[5]arenes. A (3+2) fragment coupling reaction proceeded efficiently under mild reaction conditions to produce a number of novel heteroatom‐ and methylene‐bridged corona[3]arene[2]tetrazine macrocycles. Selective oxidation of the sulfur atom between two phenylene rings afforded sulfoxide‐ and sulfone‐linked corona[5]arenes in good yields. All corona[5]arenes synthesized adopted similar 1,2,4‐alternate conformational structures, forming pentagonal cavities. The cavity sizes and the electronic properties such as redox potentials, were measured with CV and DPV, and were influenced by the different bridging units. As electron‐deficient macrocycles, the acquired corona[3]arene[2]tetrazines served as highly selective hosts, forming complexes with the hydrogen‐bonded dimer of dihydrogen phosphate through cooperative anion–π interactions. 相似文献
992.
Guangwu Li Taisuke Matsuno Yi Han Hoa Phan Shaofei Wu Qing Jiang Ya Zou Hiroyuki Isobe Jishan Wu 《Angewandte Chemie (International ed. in English)》2020,59(24):9727-9735
Synthesis of fully conjugated cyclophanes containing large‐size polycyclic aromatics is challenging. Now, three benzidine‐linked, hexa‐peri‐hexabenzocoronene (superbenzene)‐based ortho‐, para‐, and meta‐cyclophanes are synthesized through intermolecular Yamamoto coupling reaction of structurally pre‐organized precursors. Subsequent oxidative dehydrogenation gave the corresponding quinoidal benzidine‐linked cyclophanes. Their geometries were confirmed by X‐ray crystallographic analysis and their electronic properties were investigated by electronic absorption, cyclic voltammetry, and DFT calculations. The quinoidal benzidine‐linked cyclophanes show thermally populated paramagnetic activity with a relatively large singlet‐triplet energy gap. Two enantiomers for the ortho‐cyclophanes ( 1‐NH and 1‐N ) were isolated and their chiral figure‐of‐eight macrocyclic structures were identified. The cage‐like cyclophanes 2‐NH and 3‐NH with concave surface can selectively encapsulate fullerene C70. 相似文献
993.
Xiao Sun Dong Pei Wen‐Da Duan Jian‐Fei Liu Duo‐Long Di Xin‐Yi Huang 《Journal of separation science》2020,43(17):3573-3584
Elution‐extrusion counter current chromatography extrudes the most solute retained in the column with the highest possible peak resolution. It can greatly improve the hydrophobic window. In recent years, elution‐extrusion counter current chromatography has received extensive attention in the separation of complex samples. This article first reviews the development and application of elution‐extrusion counter current chromatography, including its origin, mechanism, advantages and disadvantages, and some representative applications. At the same time, this review also shared our visions and ideas on how to improve the elution‐extrusion mode. This article aims to provide certain reference for the research of this technology. 相似文献
994.
Wuqian Guo Xitao Liu Shiguo Han Yi Liu Zhiyun Xu Maochun Hong Junhua Luo Zhihua Sun 《Angewandte Chemie (International ed. in English)》2020,59(33):13879-13884
Although two‐dimensional (2D) metal–halide double perovskites display versatile physical properties due to their huge structural compatibility, room‐temperature ferroelectric behavior has not yet been reported for this fascinating family. Here, we designed a room‐temperature ferroelectric material composed of 2D halide double perovskites, (chloropropylammonium)4AgBiBr8, using an organic asymmetric dipolar ligand. It exhibits concrete ferroelectricity, including a Curie temperature of 305 K and a notable spontaneous polarization of ≈3.2 μC cm?2, triggered by dynamic ordering of the organic cation and the tilting motion of heterometallic AgBr6/BiBr6 octahedra. Besides, the alternating array of inorganic perovskite sheets and organic cations endows large mobility‐lifetime product (μτ=1.0×10?3 cm2 V?1) for detecting X‐ray photons, which is almost tenfold higher than that of CH3NH3PbI3 wafers. As far as we know, this is the first study on an X‐ray‐sensitive ferroelectric material composed of 2D halide double perovskites. Our findings afford a promising platform for exploring new ferroelectric materials toward further device applications. 相似文献
995.
Ding Yi Fei Lu Fengchu Zhang Shoujie Liu Bo Zhou Denglei Gao Xi Wang Jiannian Yao 《Angewandte Chemie (International ed. in English)》2020,59(37):15855-15859
Single‐atom catalysts have attracted much attention. Reported herein is that regulating charge transfer of lattice oxygen atoms in serial single‐atom‐doped titania enables tunable hydrogen evolution reaction (HER) activity. First‐principles calculations disclose that the activity of lattice oxygen for the HER can be regularly promoted by substituting its nearest metal atom, and doping‐induced charge transfer plays an essential role. Besides, the realm of the charge transfer of the active site can be enlarged to the second nearest atom by creating oxygen vacancies, resulting in further optimization for the HER. Various single‐atom‐doped titania nanosheets were fabricated to validate the proposed model. Taking advantage of the localized charge transfer to the lattice atom is demonstrated to be feasible for realizing precise regulation of the electronic structures and thus catalytic activity of the nanosheets. 相似文献
996.
Siyuan Li Weidong Zhang Qiang Wu Lei Fan Xinyang Wang Xiao Wang Zeyu Shen Yi He Yingying Lu 《Angewandte Chemie (International ed. in English)》2020,59(35):14935-14941
A rechargeable Li metal anode coupled with a high‐voltage cathode is a promising approach to high‐energy‐density batteries exceeding 300 Wh kg?1. Reported here is an advanced dual‐additive electrolyte containing a unique solvation structure and it comprises a tris(pentafluorophenyl)borane additive and LiNO3 in a carbonate‐based electrolyte. This system generates a robust outer Li2O solid electrolyte interface and F‐ and B‐containing conformal cathode electrolyte interphase. The resulting stable ion transport kinetics enables excellent cycling of Li/LiNi0.8Mn0.1Co0.1O2 for 140 cycles with 80 % capacity retention under highly challenging conditions (≈295.1 Wh kg?1 at cell‐level). The electrolyte also exhibits high cycling stability for a 4.6 V LiCoO2 (160 cycles with 89.8 % capacity retention) cathode and 4.95 V LiNi0.5Mn1.5O4 cathode. 相似文献
997.
Hai‐Dong Xia Zhong‐Liang Li Qiang‐Shuai Gu Xiao‐Yang Dong Jia‐Heng Fang Xuan‐Yi Du Li‐Lei Wang Xin‐Yuan Liu 《Angewandte Chemie (International ed. in English)》2020,59(39):16926-16932
We describe a photoinduced copper‐catalyzed asymmetric radical decarboxylative alkynylation of bench‐stable N‐hydroxyphthalimide(NHP)‐type esters of racemic alkyl carboxylic acids with terminal alkynes, which provides a flexible platform for the construction of chiral C(sp3)?C(sp) bonds. Critical to the success of this process are not only the use of the copper catalyst as a dual photo‐ and cross‐coupling catalyst but also tuning of the NHP‐type esters to inhibit the facile homodimerization of the alkyl radical and terminal alkyne, respectively. Owing to the use of stable and easily available NHP‐type esters, the reaction features a broader substrate scope compared with reactions using the alkyl halide counterparts, covering (hetero)benzyl‐, allyl‐, and aminocarbonyl‐substituted carboxylic acid derivatives, and (hetero)aryl and alkyl as well as silyl alkynes, thus providing a vital complementary approach to the previously reported method. 相似文献
998.
Ze‐Fan Yao Zi‐Yuan Wang Hao‐Tian Wu Yang Lu Qi‐Yi Li Lin Zou Jie‐Yu Wang Jian Pei 《Angewandte Chemie (International ed. in English)》2020,59(40):17467-17471
Controlling the solution‐state aggregation of conjugated polymers for producing specific microstructures remains challenging. Herein, a practical approach is developed to finely tune the solid‐state microstructures through temperature‐controlled solution‐state aggregation and polymer crystallization. High temperature generates significant conformation fluctuation of conjugated backbones in solution, which facilitates the polymer crystallization from solvated aggregates to orderly packed structures. The polymer films deposited at high temperatures exhibit less structural disorders and higher electron mobilities (up to two orders of magnitude) in field‐effect transistors, compared to those deposited at low temperatures. This work provides an effective strategy to tune the solution‐state aggregation to reveal the relationship between solution‐state aggregation and solid‐state microstructures of conjugated polymers. 相似文献
999.
Fei Lu Ding Yi Shoujie Liu Fei Zhan Bo Zhou Lin Gu Dmitri Golberg Xi Wang Jiannian Yao 《Angewandte Chemie (International ed. in English)》2020,59(40):17712-17718
A dual‐site catalyst allows for a synergetic reaction in the close proximity to enhance catalysis. It is highly desirable to create dual‐site interfaces in single‐atom system to maximize the effect. Herein, we report a cation‐deficient electrostatic anchorage route to fabricate an atomically dispersed platinum–titania catalyst (Pt1O1/Ti1?xO2), which shows greatly enhanced hydrogen evolution activity, surpassing that of the commercial Pt/C catalyst in mass by a factor of 53.2. Operando techniques and density functional calculations reveal that Pt1O1/Ti1?xO2 experiences a Pt?O dual‐site catalytic pathway, where the inherent charge transfer within the dual sites encourages the jointly coupling protons and plays the key role during the Volmer–Tafel process. There is almost no decay in the activity of Pt1O1/Ti1?xO2 over 300 000 cycles, meaning 30 times of enhancement in stability compared to the commercial Pt/C catalysts (10 000 cycles). 相似文献
1000.
Li‐Ming Zhao Xia‐Qiang Shen Qian Liu Wei Wu Hao‐Hong Li Zhi‐Rong Chen Yi Li 《化学:亚洲杂志》2020,15(1):136-147
Host‐guest encapsulation of functional organic dye into a porous metal‐organic framework can give rise to the development of new functional materials. In this work, by intercalating the stilbazolium‐type dye (DEAST)I (4′‐diethylamino‐N‐methyl stilbazolium) into four lanthanide layered metal‐organic complexes (Ln‐LMOCs), i. e. {[Ln(BTB)(H2O)2]?3(DMF)?2(H2O)}n (Ln=La (1), Nd (2), Sm (3), Er (4)), four responsive (DEAST)I@Ln‐LMOC composites have been prepared, serving as multifunctional performance platform. The core–shell structures of (DEAST)I@Ln‐LMOC composites have been fully characterized by IR, UV/Vis, PXRD, SEM, TEM, TGA and ESR. Significantly, after intercalation of dyes, the (DEAST)I@Ln‐LMOC composites exhibit enhanced luminescent sensing properties in detecting Fe3+ with much higher water stabilities. The luminescent sensing behavior stems from the fluorescence resonance energy transfer (FRET) from the π‐electron‐rich BTB ligands to the Fe3+, and their higher water stabilities are induced by electrostatic interactions and lower porosity. Specially, the characteristic emissions of Sm3+ will not be affected after the encapsulation guest dyes, which provide a theoretical guide for the modulation of luminescence devices. Finally, better ion conductivities and diminished photocurrents can be achieved after the embedding of the functional organic dye. In all, the formation of (DEAST)I@Ln‐LMOC composites with core–shell structures can be utilized as a multifunctional platform with good stability. 相似文献