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排序方式: 共有676条查询结果,搜索用时 171 毫秒
101.
Zudian Dai Mei Wang Yin Zhang Boya Wang Hang Luo Xuemei Zhang Dr. Qian Wang Prof. Yun Zhang Prof. Hao Wu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(40):8784-8793
Lithium–sulfur batteries (LSBs) still suffer from the shuttle effect on the cathode and the lithium dendrite on the anode. Herein, polyacrylonitrile (PAN) is developed into a bifunctional host material to simultaneously address the challenges faced on both the sulfur cathode and lithium anode in LSBs. For the sulfur cathode, PAN is bonded with sulfur to produce sulfurized PAN (SPAN) to avoid the shuttle effect. The SPAN is accommodated into a conductive 3D CNTs-wrapped carbon foam to prepare a self-supporting cathode, which improves the electronic and ionic conductivity, and buffers the volume expansion. Thereby, it delivers reversible capacity, superb rate capability, and outstanding cycling stability. For the Li-metal anode, PAN aerogel is carbonized to give macroporous N-doped cross-linked carbon nanofiber that behaves as a lithiophilic host to regulate Li plating and suppress the growth of Li dendrite. Combining the improvements for both the cathode and anode realizes a remarkable long-term cyclability (765 mAh g−1 after 300 cycles) in a full cell. It provides new opportunity to propel the practical application of advanced LSBs. 相似文献
102.
《中国化学》2018,36(3):241-246
A new multi‐functional penta‐carbazole/benzophenone hybrid compound 5CzBP was designed and synthesized through a simple one‐step catalyst‐free C—N coupling reaction by using 2,3,4,5,6‐pentafluorobenzophenone and carbazole as starting materials. 5CzBP is very soluble in tetrahydrofuran (THF), which brings an environmentally friendly device fabrication for solution‐processed OLEDs instead of most widely used chlorinated solvents when 5CzBP is employed as the bulk‐phase of organic host or non‐doped emitter in the emissive layer. 5CzBP exhibits thermally activated delayed fluorescence (TADF) characteristic with relatively high triplet energy of 2.60 eV and a low ΔEST of 0.01 eV. By using the new TADF material as organic host for another green TADF emitter, maximum external quantum efficiency (EQE) of 12.5% has been achieved in simple solution‐processed OLED device. Besides, a maximum EQE of 8.9% and 5.7% was further obtained in TADF devices based on 5CzBP as dopant and non‐doped emitter, respectively. The simultaneously acting as efficient TADF host and non‐doped TADF emitter provides the potential guidance of the future simple single‐layer two‐color white OLEDs based on low‐cost pure organic TADF materials. 相似文献
103.
Ran Li Dr. Fei Yang Liying Zhang Mengzhen Li Dr. Guo Wang Prof. Weizhi Wang Prof. Yanqing Xu Prof. Wei Wei 《Angewandte Chemie (International ed. in English)》2023,62(17):e202301267
Water-soluble small organic photothermal agents (PTAs) over NIR-II biowindow (1000–1350 nm) are highly desirable, but the rarity greatly limits their applications. Based on a water-soluble double-cavity cyclophane GBox-44+ , we report a class of host–guest charge transfer (CT) complexes as structurally uniform PTAs for NIR-II photothermal therapy. As a result of its high electron-deficiency, GBox-44+ can bind different electron-rich planar guests with a 1 : 2 host/guest stoichiometry to readily tune the CT absorption band that extends to the NIR-II region. When using a diaminofluorene guest substituted with an oligoethylene glycol chain, the host–guest system realized both good biocompatibility and enhanced photothermal conversion at 1064 nm, and was then exploited as a high-efficiency NIR-II PTA for cancer cell and bacterial ablation. This work broadens the potential applications of host–guest cyclophane systems and provides a new access to bio-friendly NIR-II photoabsorbers with well-defined structures. 相似文献
104.
The mechanism for the conformational conversion of 1,3-dioxane guest encapsulated inside a capsular host was theoretically investigated using semiempirical PM3 method and DFT methods. The free-state process of the conformational conversion of 1,3-dioxane was also investigated to make a comparison between the two different states using the same theory. The influences of the inner phase of the capsule on the conformational conversion of guest molecule were discussed via analyzing the comparative results. It was found that the capsular host could accommodate 1,3-dioxane within its cavity by the weak attractive interactions between host and guest, and it responds to the conformational conversion of guest by the deformation of hydrogen-bonding seam at the middle of the capsule. When entrapped in the capsule, the guest molecule undergoes the conformational conversion from chair form to twist-boat form slower than that under the free condition. The deformation of the capsule is favorable to maximize the attractive interactions between host and guest. 相似文献
105.
Ludden MJ Mulder A Schulze K Subramaniam V Tampé R Huskens J 《Chemistry (Weinheim an der Bergstrasse, Germany)》2008,14(7):2044-2051
In this paper the multivalent binding of hexahistidine (His6)-tagged proteins to beta-cyclodextrin (beta-CD) self-assembled monolayers (SAMs) by using the nickel(II) complex of a hetero-divalent orthogonal adamantyl nitrilotriacetate linker (4) is described. Nonspecific interactions were suppressed by using monovalent adamantyl-hexa(ethylene glycol) derivative 3. With the mono-His6-tagged maltose binding protein (His6-MBP), thermodynamic modeling based on surface plasmon resonance (SPR) titration data showed that the MBP molecules in solution were linked, on average, to Ni.4 in 1:1 stoichiometry. On the surface, however, the majority of His(6)-MBP was complexed to surface-immobilized beta-CDs through three Ni.4 complexes. This difference is explained by the high effective beta-CD concentration at the surface and is a new example of supramolecular interfacial expression. In a similar adsorption scheme, SPR proved that the alpha-proteasome could be attached to beta-CD SAMs in a specific manner. Patterning through microcontact printing of (His6)4-DsRed-fluorescent timer (DsRed-FT), which is a tetrameric, visible autofluorescent protein, was carried out in the presence of Ni.4 Fluorescence measurements showed that the (His6)4-DsRed-FT is bound strongly through Ni.4 to the molecular printboard. 相似文献
106.
The structure, molecular recognition, and inclusion effect on the photophysics of guest species are investigated for neutral and ionic cold host‐guest complexes of crown ethers (CEs) in the gas phase. Here, the cold neutral host‐guest complexes are produced by a supersonic expansion technique and the cold ionic complexes are generated by the combination of electrospray ionization (ESI) and a cryogenically cooled ion trap. The host species are 3n‐crown‐n (3nCn; n = 4, 5, 6, 8) and (di)benzo‐3n‐crown‐n ((D)B3nCn; n = 4, 5, 6, 8). For neutral guests, we have chosen water and aromatic molecules, such as phenol and benzenediols, and as ionic species we have chosen alkali‐metal ions (M+). The electronic spectra and isomer‐specific vibrational spectra for the complexes are observed with various laser spectroscopic methods: laser‐induced fluorescence (LIF); ultraviolet‐ultraviolet hole‐burning (UV‐UV HB); and IR‐UV double resonance (IR‐UV DR) spectroscopy. The obtained spectra are analyzed with the aid of quantum chemical calculations. We will discuss how the host and guest species change their flexible structures for forming best‐fit stable complexes (induced fitting) and what kinds of interactions are operating for the stabilization of the complexes. For the alkali metal ion?CE complexes, we investigate the solvation effect by attaching water molecules. In addition to the ground‐state stabilization problem, we will show that the complexation leads to a drastic effect on the excited‐state electronic structure and dynamics of the guest species, which we call a “cage‐like effect”. 相似文献
107.
Solhe F. Alshahateet 《Molecular Crystals and Liquid Crystals》2016,625(1):186-194
The tetrahalo aryl inclusion host 2,4,10,12-tetrabromo-6,7,14,15-tetrahydro-6,14-thiacycloocta[1,2-b:5,6-b’]diquinoline 3 was re-synthesized to explore its ability to trap toxic polychlorinated hydrocarbons such as 1,1,2,2-tetrachloroethane (TCE) in the form of host–guest compound. Host 3 crystallizes from a fresh sample of TCE to form an inclusion compound of the formula (3)2·(TCE) in triclinic system, space group P-1, with a = 7.7732(16) Å, b = 10.739(2) Å, c = 14.816(3) Å, α = 97.329(4)°, β = 98.619(4)°, γ = 103.359(4)°, V = 1172.7(4) Å3, and Z = 2. The X-ray crystal structure of the (3)2·(1,1,2,2-TCE) is described and analyzed in terms of crystal engineering and supramolecular chemistry. The hosts assemble by means of different types of packing motifs. The included TCE molecules are enclosed within host molecular pens. Novel halogen···halogen intermolecular interactions as well as other non-covalent intermolecular interactions involved in the crystal structure are presented and proved to play an important role in linking these host–host, host–guest, and guest–guest building blocks. 相似文献
108.
Tristan A. Geervliet Ionela Gavrila Giuseppe Iasilli Francesco Picchioni Andrea Pucci 《化学:亚洲杂志》2019,14(6):877-883
This study reports for the first time the use of bio‐based alternatives for PMMA as host matrix for luminescent solar concentrators (LSCs). Notably, two types of renewable polyesters were synthesized in varying molar ratios via a two‐step melt‐polycondensation reaction with dibutyl tin oxide as catalyst. The first is a homopolymer of diethyl 2,3:4,5‐di‐O‐methylene galactarate (GxMe) and isosorbide (IGPn), and the second is a random copolymer of GxMe with 1,3‐propanediol and dimethyl terephthalate (GTPn). The two polyesters were found to be optically transparent, totally amorphous with a Tg higher than 45 °C and temperature resistance comparable to PMMA. Lumogen Red (LR) and an aggregation‐induced emission (AIE) fluorophore, TPETPAFN, were utilized as fluorophores and the derived thin polymer films (25 μm) were found highly homogeneous, especially for those prepared from GTPn, possibly due to the presence of compatibilizing terephthalate units in the matrix composition and the higher molecular weight. The spectroscopic characterization and the optical efficiency determination (ηopt) evidenced LSCs performances similar or superior to those collected from LR/PMMA thin films. Noteworthy, ηopt of 7.7 % and 7.1 % were recorded for the GTPn‐based matrix containing LR and TPETPAFN, respectively, thus definitely supporting the bio‐based polyesters as renewable and highly fluorophore‐compatible matrices for high‐performance LSCs. 相似文献
109.
New types of polyurethanes (PUs) were prepared from condensation polymerization of isophorone diisocyanate (IPDI) with various combination of 9-butyl-3,6-bis(4-hydroxyphenyl)carbazole (Cz) and 2,5-bis(4-hydroxyphenyl)-1,3,4-oxadiazole (OXD), and end-capped with 4-tert-butyl phenol. The Cz-OXD PUs can also be used as host for phosphorescent dye. Red EL emission was obtained when Ir(btp)2(acac) or Ir(2-phq)2(acac) was used as the phosphorescent dyes in Cz-OXD (3:1) PU. Maximum brightness of 394 cd/m2 and EL efficiency of 1 cd/A were achieved for the Ir(2-phq)2(acac) base device. In addition, white light PLED was demonstrated when co-dopant of Ir(btp)2(acac) and Firpic were used. 相似文献
110.