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961.
Yanan Jiang Wenjie Ma Yujuan Qiao Yifei Xue Jiahao Lu Jun Gao Nannan Liu Fei Wu Prof. Ping Yu Prof. Lei Jiang Prof. Lanqun Mao 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(31):12895-12899
Biological ion channels and ion pumps with sub-nanometer sizes modulate ion transport in response to external stimuli. Realizing such functions with sub-nanometer solid-state nanopores has been an important topic with wide practical applications. Herein, we demonstrate a biomimetic photoresponsive ion channel and photodriven ion pump using a porphyrin-based metal–organic framework membrane with pore sizes comparable to hydrated ions. We show that the molecular-size pores enable precise and robust optoelectronic ion transport modulation in a broad range of concentrations, unparalleled with conventional solid-state nanopores. Upon decoration with platinum nanoparticles to form a Schottky barrier photodiode, photovoltage across the membrane is generated with “uphill” ion transport from low concentration to high concentration. These results may spark applications in energy conversion, ion sieving, and artificial photosynthesis. 相似文献
962.
Yue Sun Dr. Tiandu Dong Dr. Chunxin Lu Weiwen Xin Linsen Yang Pei Liu Yongchao Qian Yuanyuan Zhao Dr. Xiang-Yu Kong Prof. Liping Wen Prof. Lei Jiang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(40):17576-17581
Osmotic energy, obtained through different concentrations of salt solutions, is recognized as a form of a sustainable energy source. In the past years, membranes derived from asymmetric aromatic compounds have attracted attention because of their low cost and high performance in osmotic energy conversion. The membrane formation process, charging state, functional groups, membrane thickness, and the ion-exchange capacity of the membrane could affect the power generation performance. Among asymmetric membranes, a bipolar membrane could largely promote the ion transport. Here, two polymers with the same poly(ether sulfone) main chain but opposite charges were synthesized to prepare bipolar membranes by a nonsolvent-induced phase separation (NIPS) and spin-coating (SC) method. The maximum power density of the bipolar membrane reaches about 6.2 W m−2 under a 50-fold salinity gradient, and this result can serve as a reference for the design of bipolar membranes for osmotic energy conversion systems. 相似文献
963.
Jiancheng Rao Liuqing Yang Xuefei Li Dr. Lei Zhao Dr. Shumeng Wang Prof. Junqiao Ding Prof. Lixiang Wang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(41):18059-18065
The meta junction is proposed to realize efficient thermally activated delayed fluorescence (TADF) in donor–acceptor (D-A) conjugated polymers. Based on triphenylamine as D and dicyanobenzene as A, as a proof of concept, a series of D-A conjugated polymers has been developed by changing their connection sites. When the junction between D and A is tuned from para to meta, the singlet–triplet energy splitting (ΔEST) is found to be significantly decreased from 0.44 to 0.10 eV because of the increasing hole–electron separation. Unlike the para-linked analogue with no TADF, consequently, the meta-linked polymer shows a strong delayed fluorescence. Its corresponding solution-processed organic light-emitting diodes (OLEDs) achieve a promising external quantum efficiency (EQE) of 15.4 % (51.9 cd A−1, 50.9 lm W−1) and CIE coordinates of (0.34, 0.57). The results highlight the bright future of D-A conjugated polymers used for TADF OLEDs. 相似文献
964.
Dr. Xiao-Gang Wang Lei Xu Min-Jie Li Prof. Dr. Xian-Zheng Zhang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(41):18234-18242
Multi-component MOFs contain multiple sets of unique and hierarchical pores, with different functions for different applications, distributed in their inter-linked domains. Herein, we report the construction of a class of precisely aligned flexible-on-rigid hybrid-phase MOFs with a unique rods-on-octahedron morphology. We demonstrated that hybrid-phase MOFs can be constructed based on two prerequisites: the partially matched topology at the interface of the two frameworks, and the structural flexibility of MOFs with acs topology, which can compensate for the differences in lattice parameters. Furthermore, we achieved domain selective loading of multiple guest molecules into the hybrid-phase MOF, as observed by scanning transmission electron microscopy–energy-dispersive X-ray spectrometry elemental mapping. Most importantly, we successfully applied the constructed hybrid-phase MOF to develop a dual-drug delivery system with controllable loading ratio and release kinetics. 相似文献
965.
Meng Lv Yang Yu María E. Sandoval-Salinas Prof. Jianhua Xu Dr. Zuhai Lei Prof. David Casanova Prof. Youjun Yang Prof. Jinquan Chen 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(49):22363-22368
Spiro conjugation has been proposed to dictate the efficiency of charge transfer, which could directly affect the spin–orbit charge transfer intersystem crossing (SOCT-ISC) process. However, this process has yet to be exemplified. Herein, we prepared three spirobis[anthracene]diones, in which two benzophenone moieties are locked in close proximity and differentially functionalized to fine-tune the charge transfer state. Its feasibility for SOCT-ISC was theoretically predicted, then experimentally evaluated. Through fine-tuning the spiro conjugation coupling and varying the solvent dielectric constants, ISC rate constants were engineered to vary in a dynamic range of three orders of magnitude, from 7.8×108 s−1 to 1.0×1011 s−1, which is the highest ISC rate reported for SOCT-ISC system to our knowledge. Our findings substantiate the key factors for effective SOCT-ISC and offer a new avenue for the rational design of heavy atom free triplet sensitizers. 相似文献
966.
采用电喷雾离子化沉积技术, 在氟掺杂锡氧化物(FTO)衬底上制备了均匀的无定形铁镍双金属氢氧化物薄膜. 与浸泡法制备的薄膜相比, 该薄膜具有更高的纯度、 更大的比表面积和较高的电催化水氧化性能, 在10 mA/cm 2时的过电位为290 mV, 并在催化反应中表现出良好的稳定性, 为可控合成高催化活性的过渡金属氢氧化物薄膜提供了一种新方法. 相似文献
967.
采用来源于可再生资源的聚醚酰胺弹性体(PEBA)增韧聚乳酸(PLA)制备超韧聚乳酸(PLA/PEBA-GMA)复合材料.为了提高PEBA与PLA之间的相容性,选择极性单体甲基丙烯酸缩水甘油酯(GMA)、共接枝单体乙烯基吡咯烷酮(NVP)及引发剂过氧化二异丙苯(DCP)对PEBA进行接枝改性制备PEBA-GMA.研究了接枝单体组分的用量(m/g)对PLA/PEBA-GMA复合材料性能的影响.研究发现,随着接枝单体组分用量的提高,复合材料的缺口冲击强度逐渐增大,当接枝单体组分GMA,NVP和DCP的用量分别为2.5,2.5和0.25 g时,复合材料的冲击强度高达88.6 kJ/m2,断裂伸长率为164.1%.研究表明,在熔融共混过程中,聚乳酸的端基(—OH和—COOH)与PEBA-GMA上环氧基团发生反应,有效改善两相间的界面相容性,随着接枝单体组分比例的提高,分散相PEBA-GMA的粒子尺寸逐渐减小且分布均匀. 相似文献
968.
采用程序升温还原法和次磷酸盐歧化法制备了Ni_2P/SiO_2催化剂,结合现代仪器分析表征技术,研究了制备方法对Ni_2P/SiO_2催化剂结构和萘加氢性能的影响。结果表明,两种方法均可制备出仅含Ni_2P活性相的Ni_2P/SiO_2催化剂,在反应温度340℃、氢气压力4 MPa、空速为20.8 h~(-1)下,程序升温还原法制备的Ni_2P/SiO_2催化剂表现出更高的萘加氢活性,这主要是因为程序还原法制备的Ni_2P/SiO_2催化剂中有更多Ni_2P物种生成,提供了较多的活性位点(CO吸附量21.6μmol/g);且催化剂表面弱酸位点多,有利于芳烃吸附。当选用程序升温还原法制备Ni_2P/SiO_2催化剂时,在保证生成纯相Ni_2P的前提下,较低的Ni/P比更有利于合成高加氢活性的Ni_2P/SiO_2催化剂。 相似文献
969.
AbstractA metal-free and base-free strategy was developed in DES to synthesize styrenes for the first time by decarboxylation of cinnamic acid derivatives, which provided a renewable and cost efficiently protocol to access various styrenes including those with functional groups such as 4-vinylphenol and 1-chloro-4-vinylbenzene. 相似文献
970.
Guohai Deng Shujun Lei Dr. Sudip Pan Jiaye Jin Prof. Guanjun Wang Prof. Lili Zhao Prof. Mingfei Zhou Prof. Gernot Frenking 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(46):10487-10500
Homoleptic Group 4 metal carbonyl cation and neutral complexes were prepared in the gas phase and/or in solid neon matrix. Infrared spectroscopy studies reveal that both zirconium and hafnium form eight-coordinate carbonyl neutral and cation complexes. In contrast, titanium forms only the six-coordinate Ti(CO)6+ and seven-coordinate Ti(CO)7. Titanium octacarbonyl Ti(CO)8 is unstable as a result of steric repulsion between the CO ligands. The 20-electron Zr(CO)8 and Hf(CO)8 complexes represent the first experimentally observed homoleptic octacarbonyl neutral complexes of transition metals. The molecules still fulfill the 18-electron rule, because one doubly occupied valence orbital does not mix with any of the metal valence atomic orbitals. Zr(CO)8 and Hf(CO)8 are stable against the loss of one CO because the CO ligands encounter less steric repulsion than Zr(CO)7 and Hf(CO)7. The heptacarbonyl complexes have shorter metal−CO bonds than that of the octacarbonyl complexes due to stronger electrostatic and covalent bonding, but the significantly smaller repulsive Pauli term makes the octacarbonyl complexes stable. 相似文献