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991.
992.
993.
Hai Huang Junzhen Fan Dr. Guangke He Zhimin Yang Xiaodong Jin Qi Liu Prof. Dr. Hongjun Zhu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(7):2532-2538
A novel method for metal‐free oxothiolation of ynamides to construct oxazolidine‐2,4‐diones bearing sulfur‐substituted quaternary carbon atoms has been developed. It represents a rare C?O bond cleavage of ynamides, as well as a facile and tandem approach for the formation of C?O, C?S, and C?Cl bonds. This redox‐neutral protocol can be applied to the synthesis of multisubstituted oxazolidine‐2,4‐diones with good chemoselectivity and good yields of isolated products under mild conditions. 相似文献
994.
Prof. Dr. Yu Feng Hui Chen Zhi‐Xiong Liu Yan‐Mei He Prof. Dr. Qing‐Hua Fan 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(14):4980-4990
An interesting halogen‐substituent effect on the organogelation properties of poly(benzyl ether) dendrons is reported. A new class of poly(benzyl ether) dendrons with halo substituents decorating their periphery was synthesized and fully characterized. A systematic study on the gelation abilities, thermotropic behaviors, aggregated microstructures, and mechanical properties of self‐assembled organogels was performed to elucidate the halogen‐substituent effects on their organogelation propensity. It was found that the exact halogen substitutions on the periphery of dendrons exert a profound effect on the organogelation propensity, and dendrons G n ‐Cl (n=2, 3) and G2‐I proved to be highly efficient organogelators. The cooperation of multiple π–π, dispersive halogen, CH–π, and weak C?H ??? X hydrogen‐bonding interactions were found to be the key contributor to forming the self‐assembled gels. Dendritic organogels formed from G n ‐Cl (n=2, 3) in 1,2‐dichloroethane exhibited thixotropic‐responsive properties, and such thixotropic organogels are promising materials for future research and applications. 相似文献
995.
Prof. Dr. Dawei Wang Xiaoli Yu Prof. Dr. Xiang Xu Bingyang Ge Xiaoli Wang Yaxuan Zhang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(25):8663-8668
An Rh‐catalyzed selective C?H bond activation of diaryl‐substituted anilides is described. In an attempt to achieve C?H activation of C‐aryl rings, we unexpectedly obtained an N‐aryl ring product under non‐coordinating anion conditions, whereas the C‐aryl ring product was obtained in the absence of a non‐coordinating anion. This methodology has proved to be an excellent means of tuning and adjusting selective C?H bond activation of C‐aryl and N‐aryl rings. The approach has been rationalized by mechanistic studies and theoretical calculations. In addition, it has been found and verified that the catalytic activity of the rhodium catalyst is obviously improved by non‐coordinating anions, which provides an efficient strategy for obtaining a highly chemoselective catalyst. Mechanistic experiments also unequivocally ruled out the possibility of a so‐called “silver effect” in this transformation involving silver. 相似文献
996.
Hierarchical NiCo2S4 Nanotube@NiCo2S4 Nanosheet Arrays on Ni Foam for High‐Performance Supercapacitors 下载免费PDF全文
Dr. Haichao Chen Si Chen Hongyan Shao Dr. Chao Li Dr. Meiqiang Fan Dr. Da Chen Dr. Guanglei Tian Prof. Dr. Kangying Shu 《化学:亚洲杂志》2016,11(2):248-255
Hierarchical NiCo2S4 nanotube@NiCo2S4 nanosheet arrays on Ni foam have been successfully synthesized. Owing to the unique hierarchical structure, enhanced capacitive performance can be attained. A specific capacitance up to 4.38 F cm?2 is attained at 5 mA cm?2, which is much higher than the specific capacitance values of NiCo2O4 nanosheet arrays, NiCo2S4 nanosheet arrays and NiCo2S4 nanotube arrays on Ni foam. The hierarchical NiCo2S4 nanostructure shows superior cycling stability; after 5000 cycles, the specific capacitance still maintains 3.5 F cm?2. In addition, through the morphology and crystal structure measurement after cycling stability test, it is found that the NiCo2S4 electroactive materials are gradually corroded; however, the NiCo2S4 phase can still be well‐maintained. Our results show that hierarchical NiCo2S4 nanostructures are suitable electroactive materials for high performance supercapacitors. 相似文献
997.
An Enantioselective Assembly of Dihydropyranones through an NHC/LiCl‐Mediated in situ Activation of α,β‐Unsaturated Carboxylic Acids 下载免费PDF全文
Yonglei Que Yinan Lu Wenjing Wang Yuhong Wang Haotian Wang Chenxia Yu Tuanjie Li Xiang‐Shan Wang Shide Shen Changsheng Yao 《化学:亚洲杂志》2016,11(5):678-681
A straightforward N‐heterocyclic carbene (NHC)/LiCl‐mediated synthesis of dihydropyranones from α,β‐unsaturated carboxylic acids and 1,3‐dicarbonyl compounds was realized through the in situ activation strategy. The key advantages of this protocol include ready availability and high stability of starting materials, good yields, and excellent enantioselectivity. 相似文献
998.
Charge Transfer Through Dithieno[2,3‐a:3′,2′‐c]phenazine: Effect of Substitution Pattern on the Optoelectronic Properties of Regioisomeric Luminophores 下载免费PDF全文
Two series of regioisomeric luminophores that contained a dithieno[2,3‐a:3′,2′‐c]phenazine (DTP) unit as an electron acceptor have been designed and synthesized. To investigate the effect of substitution pattern on the optoelectronic properties of these luminophores, electron donors (N,N‐dihexylaniline or N,N‐dihexyl‐4‐vinylaniline) were incorporated at the 2,5‐, 8,11‐, and 9,10‐positions of the DTP unit. We found that the optoelectronic properties of the regioisomeric luminophores were greatly affected by the substitution pattern: functionalization at the 8,11‐positions of the DTP unit was superior to the other two substitution patterns in extending the effective π‐conjugation and strengthening the intramolecular charge‐transfer interactions. Moreover, the insertion of vinyl groups between the DTP and N,N‐dihexylaniline units narrowed the energy band‐gap for isomers 4 and 5 . However, hypsochromically shifted absorption and photoluminescence maxima were observed for isomeric luminophore 6 , in which electron donors were substituted at the 2,5‐positions of the DTP unit. These results should facilitate greater understanding of the structure–property relationships in regioisomeric semiconductors and present a new way to design optoelectronic materials with effective substitution patterns. 相似文献
999.
A Study of Different Doped Metal Cations on the Physicochemical Properties and Catalytic Activities of Ce20M1Ox (M=Zr,Cr, Mn,Fe, Co,Sn) Composite Oxides for Nitric Oxide Reduction by Carbon Monoxide 下载免费PDF全文
Changshun Deng Min Li Junning Qian Qun Hu Dr. Meina Huang Qingjin Lin Yongshun Ruan Dr. Lihui Dong Prof. Bin Li Prof. Minguang Fan 《化学:亚洲杂志》2016,11(15):2144-2156
This work is mainly focused on investigating the effects of different doped metal cations on the formation of Ce20M1Ox (M=Zr, Cr, Mn, Fe, Co, Sn) composite oxides and their physicochemical and catalytic properties for NO reduction by CO as a model reaction. The obtained samples were characterized by using N2 physisorption, X‐ray diffraction, laser Raman spectroscopy, UV/Vis diffuse reflectance spectroscopy, inductively coupled plasma atomic emission spectroscopy, X‐ray photoelectron spectroscopy, temperature‐programmed reduction by hydrogen and by oxygen (H2‐TPR and O2‐TPD), in situ diffuse reflectance infrared Fourier transform spectroscopy, and the NO+CO model reaction. The results imply that the introduction of Mx+ into the lattice of CeO2 increases the specific surface area and pore volume, especially for variable valence metal cations, and enhances the catalytic performance to a great extent. In this regard, increases in the oxygen vacancies, reduction properties, and chemisorbed O2? (and/or O?) species of these Ce20M1Ox composite oxides (M refers to variable valence metals) play significant roles in this reaction. Among the samples, Ce20Cr1Ox exhibited the best catalytic performance, mainly because it has the best reducibility and more chemisorbed oxygen, and significant reasons for these attributes may be closely related to favorable synergistic interactions of the vacancies and near‐surface Ce3+ and Cr3+. Finally, a possible reaction mechanism was tentatively proposed to understand the reactions. 相似文献
1000.
6‐TIPS‐β‐Cyclodextrin‐Modified Fe3O4 for Facile Enantioseparation of 1‐(1‐Naphthyl)ethylamine 下载免费PDF全文
Lu Wang Xiang‐Yong Liang Prof. Dr. Li‐Sheng Ding Prof. Dr. Sheng Zhang Prof. Dr. Bang‐Jing Li 《化学:亚洲杂志》2016,11(24):3513-3519
A new type of chiral magnetic nanoparticle was prepared from covalently linked magnetic nanoparticles (Fe3O4) and heptakis‐(6‐O‐triisopropylsilyl)‐β‐cyclodextrin (6‐TIPS‐β‐CD). The resulting selectors (TIPS‐β‐CD‐MNPs) combined the good magnetic properties Fe3O4 and efficient chiral recognition ability of 6‐TIPS‐β‐CD. The enantioselectivity of TIPS‐β‐CD‐MNPs towards 1‐(1‐naphthyl)ethylamine was six times higher than that of the parent β‐CD modified Fe3O4 particles. 相似文献