Institution
Xi'an Jiaotong University
Education•Xi'an, China•
About: Xi'an Jiaotong University is a education organization based out in Xi'an, China. It is known for research contribution in the topics: Heat transfer & Dielectric. The organization has 85440 authors who have published 99682 publications receiving 1579683 citations. The organization is also known as: '''Xi'an Jiaotong University''' & Xi'an Jiao Tong University.
Papers published on a yearly basis
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TL;DR: In this paper, the authors explore how four types of justice (distributive, procedural, interpersonal, and informational) influence dyadic relationship performance in the buyer-supplier context.
249 citations
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TL;DR: In this article, the development of the effective thermal conductivity models for the nanoporous silica aerogel insulation material was summarized, and the procedure of establishing the effective heat transfer model of the aerogels insulation material from nanoscale to macroscale was introduced by taking their previous work as an illustration.
249 citations
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TL;DR: An unprecedented trifluoromethylation-initiated radical 1,2-aryl migration(“neophyl rearrangement”) in a,adiaryl allylic alcohols utilizing 1, leading to a wide variety of acyclic b-triflu oromethyle ketones 3, which would provide important insight into the reaction mechanism.
Abstract: The trifluoromethyl (CF3) group is an important structural motif in many pharmaceutically relevant molecules because of its unique chemical and metabolic stability, lipophilicity, and binding selectivity. Consequently, much effort has been directed toward the development of efficient methods for the introduction of the trifluoromethyl group into small molecules. While a variety of processes have been reported to generate aromatic C(sp) CF3 bonds, the analogous direct trifluoromethylation of alkenes and their derivatives has received less attention. In 2011, the groups of Buchwald, Liu, and Wang independently reported efficient allylic trifluoromethylation of unactivated alkenes with copper catalysts under mild conditions. The trifluoromethylation of allylsilanes, vinyltrifluoroborates, and enamides has since been disclosed by several groups, allowing the effective formation of compounds with a CF3 group in an allylic or vinylic position. Furthermore, oxytrifluoromethylation, carbotrifluoromethylation, and hydrotrifluoromethylation of alkenes have been achieved with and without transition-metal catalysis. These reactions provide a valuable array of highly regioselective C CF3 bond-forming methods under mild conditions. However, the mechanism of these copper-catalyzed trifluoromethylation reactions is not fully understood. Addition of both the trifluoromethyl cation or radical have been suggested as routes to the observed products. Buchwald reported the efficient formation of CF3-containing epoxides from secondary allylic alcohols, possibly via intermediate A [Eq. (1)]. Thus, we envisioned that the trifluoromethylation of a,a-diaryl allylic alcohols 2 with the Togni reagent (1) would lead to the analogous intermediates B, which could undergo 1,2-aryl migration to provide btrifluoromethyl ketones 3 [Eq. (2)]. Importantly, electronrich aryl groups migrate preferentially in cationic (semipinacol) rearrangements, whereas electron-poor aryl groups migrate preferentially in radical (“neophyl”) rearrangements. Therefore, the structures of the products from unsymmetrical substrates would provide important insight into the reaction mechanism. b-Trifluoromethyl ketones such as 3 are difficult to prepare. Nucleophilic trifluoromethylating reagents typically undergo 1,2-addition to enones, affording trifluoromethyl allylic alcohols rather than b-trifluoromethyl ketones by 1,4addition. Only a few cyclic b-trifluoromethyl ketones have been prepared by 1,4-addition of a nucleophilic CF3 group to cyclic enones. The use of radical or electrophilic CF3 reagents for this challenging task has been rarely described. Consequently, we wanted to develop new C(sp) CF3 bond-forming reactions to prepare b-trifluoromethyl ketones, and to probe the mechanism of the copper-catalyzed trifluoromethylation of alkenes as discussed above. We report herein an unprecedented trifluoromethylation-initiated radical 1,2-aryl migration(“neophyl rearrangement”) in a,adiaryl allylic alcohols utilizing 1, leading to a wide variety of acyclic b-trifluoromethyl a-aryl ketones 3. We commenced our study with the reaction of 2a with the Togni reagent (1) and [(MeCN)4Cu]PF6 as catalyst (Table 1). To our delight, the reaction in methanol at 50 8C for 14 h afforded the desired rearranged product 3a in 27% yield (entry 1). It also provided 48% of compound 4a, which was probably derived by trapping of the allylic cation of 2a by MeOH. Complex product mixtures were obtained when the reaction was performed in the less nucleophilic alcohols trifluoroethanol or hexafluoroisopropanol (HFIP; entries 2 and 3, respectively). In acetonitrile and dichloromethane, mixtures of the desired ketone 3a (22% and 9%, respectively) and substitution product 4b (23% and 76%, respectively, entries 4 and 5) were formed. In DMSO, the yield of 3a increased to 51%, but the conversion was not complete (entry 6). In DMF, the yield of 3a increased further to 69% [*] X. Liu, F. Xiong, X. Huang, Prof. Dr. X. Wu Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences 190 Kaiyuan Avenue, Guangzhou 510530 (China) E-mail: wu_xiaoxing@gibh.ac.cn
249 citations
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TL;DR: It is found that TFPL possesses potent antioxidant and free radical scavenging activities that could contribute, at least in part, to the traditionally claimed therapeutic benefits of persimmon leaves.
249 citations
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TL;DR: The results demonstrate that side-chain conjugation can tune energy levels, enhance absorption, and electron mobility, and finally enhance photovoltaic performance of nonfullerene acceptors.
Abstract: A side-chain conjugation strategy in the design of nonfullerene electron acceptors is proposed, with the design and synthesis of a side-chain-conjugated acceptor (ITIC2) based on a 4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b′]di(cyclopenta-dithiophene) electron-donating core and 1,1-dicyanomethylene-3-indanone electron-withdrawing end groups. ITIC2 with the conjugated side chains exhibits an absorption peak at 714 nm, which redshifts 12 nm relative to ITIC1. The absorption extinction coefficient of ITIC2 is 2.7 × 105m−1 cm−1, higher than that of ITIC1 (1.5 × 105m−1 cm−1). ITIC2 exhibits slightly higher highest occupied molecular orbital (HOMO) (−5.43 eV) and lowest unoccupied molecular orbital (LUMO) (−3.80 eV) energy levels relative to ITIC1 (HOMO: −5.48 eV; LUMO: −3.84 eV), and higher electron mobility (1.3 × 10−3 cm2 V−1 s−1) than that of ITIC1 (9.6 × 10−4 cm2 V−1 s−1). The power conversion efficiency of ITIC2-based organic solar cells is 11.0%, much higher than that of ITIC1-based control devices (8.54%). Our results demonstrate that side-chain conjugation can tune energy levels, enhance absorption, and electron mobility, and finally enhance photovoltaic performance of nonfullerene acceptors.
249 citations
Authors
Showing all 86109 results
Name | H-index | Papers | Citations |
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Feng Zhang | 172 | 1278 | 181865 |
Yang Yang | 164 | 2704 | 144071 |
Jian Yang | 142 | 1818 | 111166 |
Lei Zhang | 130 | 2312 | 86950 |
Yang Liu | 129 | 2506 | 122380 |
Jian Zhou | 128 | 3007 | 91402 |
Chao Zhang | 127 | 3119 | 84711 |
Bin Wang | 126 | 2226 | 74364 |
Xin Wang | 121 | 1503 | 64930 |
Bo Wang | 119 | 2905 | 84863 |
Xuan Zhang | 119 | 1530 | 65398 |
Jian Liu | 117 | 2090 | 73156 |
Andrey L. Rogach | 117 | 576 | 46820 |
Yadong Yin | 115 | 431 | 64401 |
Xin Li | 114 | 2778 | 71389 |