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51.
Meiyun Xue Hongxue Huang Yanxiong Ke Changhu Chu Yu jin Xinmiao Liang 《Journal of chromatography. A》2009,1216(49):8623-8629
2D-HPLC is an important technique for the separation of complex samples. Developing new types of stationary phases is of great interest to construct 2D-LC systems with high orthogonality. In this study, a novel stationary phase-Click dipeptide (l-phenylglycine dipeptide) was prepared by immobilization of α-azido l-phenylglycine dipeptide on alkyne-silica via click chemistry. In the preparation of this new material, an efficient, inexpensive and shelf-stable diazo transfer reagent (imidazole-1-sulfonyl azide hydrochloride) was utilized to transfer the amino group of l-phenylglycine to corresponding azido group under mild conditions. The Click dipeptide thus prepared was confirmed by FT-IR, solid state CP/MAS 13C NMR and elemental analysis. The Click dipeptide packing showed high orthogonality with C18, which reached 63.5%. An off-line 2D-RP/RPLC system was developed to analyze a traditional Chinese medicine (TCM)-Rheum Palmatum L. The results showed high orthogonality between Click dipeptide and C18 as well as great separating power in the practical separation of complex samples. 相似文献
52.
Shengjie Zhang Junhao Li Ningyi Jiang Xuqiu Li Sivakumar Pasupath Yanxiong Fang Quanbing Liu Dai Dang 《化学:亚洲杂志》2019,14(16):2810-2814
It is a very urgent and important task to improve the safety and high‐temperature performance of lithium/lithium‐ion batteries (LIBs). Here, a novel ionic liquid, 1‐(2‐ethoxyethyl)‐1‐methylpyrrolidinium bis(trifluoromethylsulfonyl)imide (PYR1(2o2)TFSI), was designed and synthesized, and then mixed with dimethyl carbonate (DMC) as appropriate solvent and LiTFSI lithium salt to produce an electrolyte with high ionic conductivity for safe LIBs. Various characterizations and tests show that the highly flexible ether group could markedly reduce the viscosity and provide coordination sites for Li‐ion, and the DMC could reduce the viscosity and effectively enhance the Li‐ion transport rate and transference number. The electrolyte exhibits excellent electrochemical performance in Li/LiFeO4 cells at room temperature as well as at a high temperature of 60 °C. More importantly, with the addition of DMC, the IL‐based electrolyte remains nonflammable and appropriate DMC can effectively inhibit the growth of lithium dendrites. Our present work may provide an attractive and promising strategy for high performance and safety of both lithium and lithium‐ion batteries. 相似文献
53.
MA Hanze WANG Shaoyu REN Yanxiong WANG Yuhan ZHU Ziting HE Guangwei JIANG Zhongyi 《高等学校化学研究》2022,38(2):325-338
Covalent organic framework(COF) membranes have exhibited great potential to become the next-generation membranes for efficient separations due to the diverse structures, ordered framework pores, tunable functionality and excellent stability. This review presents the microstructure manipulation strategies for separation performance enhancement of COF membranes in recent years. Based on the three mechanisms of molecular sieving, surface diffusion, and facilitated transport, the structural modulation methods to enhance the selectivity of COF membranes are analyzed in detail. Next, strategies of realizing ultrashort mass transfer pathways and ultralow mass transfer resistance for the permeability enhancement are elaborated. Furthermore, the framework stability in COFs, interlayer stability between COF nanosheets and interfacial stability between COF layer and substrate are discussed. Finally, we discuss the existing challenges and perspectives on the future development of COF membranes, targeting at identifying the most promising strategies and directions for the engineering of COF membranes. 相似文献
54.
Preparation and evaluation of novel chiral stationary phases based on quinine derivatives comprising crown ether moieties 下载免费PDF全文
Dongqiang Wang Jianchao Zhao Haixia Wu Haibo Wu Jianfeng Cai Yanxiong Ke Xinmiao Liang 《Journal of separation science》2015,38(2):205-210
The C9‐position of quinine was modified by meta‐ or para‐substituted benzo‐18‐crown‐6, and immobilized on 3‐mercaptopropyl‐modified silica gel through the radical thiol‐ene addition reaction. These two chiral stationary phases were evaluated by chiral acids, amino acids, and chiral primary amines. The crown ether moiety on the quinine anion exchanger provided a ligand‐exchange site for primary amino groups, which played an important role in the retention and enantioselectivity for chiral compounds containing primary amine groups. These two stationary phases showed good selectivity for some amino acids. The complex interaction between crown ether and protonated primary amino group was investigated by the addition of inorganic salts such as LiCl, NH4Cl, NaCl, and KCl to the mobile phase. The resolution results showed that the simultaneous interactions between two function moieties (quinine and crown ether) and amino acids were important for the chiral separation. 相似文献
55.
Cesar H. Zambrano Jorden P. Kass Eric Efrain Dueno Yanxiong Ke Hong-Cai Zhou 《Journal of chemical crystallography》2006,36(1):67-70
The aromatic derivative 2,8,14,20-tetranaphthylpyrogallol[4]arene was synthesized by the acid catalyzed condensation of 2-naphthaldehyde and pyrogallol in refluxing aqueous ethanol. Single crystal X-ray analysis revealed that the molecule crystallizes in a triclinic space group P1(bar) No. 2, with a = 11.3396(7) Å, b = 15.9942(10) Å, c = 26.3653(17) Å, α = 94.309(2)°, β = 91.765(2)°, γ = 93.892(2)°, D
calc = 1.298 g/m3 for Z = 1. Within the unit cell, six methanol molecules of crystallization plus one molecule of pyrazine were found to accompany the pyrogallol macrocycle. In the solid state, the macrocycle is found to adopt the chair conformation. 相似文献
56.
57.
A new two dimensional zinc complex was reported. This compound was synthesized under solvothermal condition by using THF as solvent. The crystal structure was determined by using single crystal X-ray diffraction. Crystal data: Zr', (B DC)( D ABCO)( H 20)z, monoclinic, space group C 2/c,a =10.871(17),b=19.10 (3),c=7.15 5(川,a= 90,口二115.99(3),Y=90,Z 二8,V 二1335(4),Dr二2.085岁cm3,R二0.08 58. This compound has two-dimensional network structure. Each zinc metal center was coordinated by two DABCO, two BDC and one water molecule. DABCO and BDC ligands bridge to two zinc atoms, respectively. The extension of this〔。-ordination result in a two-dimensional network and form a 7.16 x 9.98A zporous structure. It was interesting to find that the 2-dimensional was an interpenetrated structure formed by two coordinate polymer networks. This kind of structure is very rare in the coordinate compounds. The m-m interaction between the phenyl group of BDC was believed to the key of the growth of this coordination network. 相似文献
58.
Let H be a subgroup of a finite group G. H is said to be λ-supplemented in G if G has a subgroup T such that G = HT and H ∩ T ≤ H SE , where H SE denotes the subgroup of H generated by all those subgroups of H, which are S-quasinormally embedded in G. In this article, some results about the λ-supplemented subgroups are obtained, by which we determine the structure of some classes of finite groups. In particular, some new characterizations of p-supersolubility of finite groups are given under the assumption that some primary subgroups are λ-supplemented. As applications, a number of previous known results are generalized. 相似文献
59.
The degree pattern of a finite group G associated with its prime graph has been introduced by Moghaddamfar in 2005 and it is proved that the following simple groups are uniquely determined by their order and degree patterns:All sporadic simple groups,the alternating groups Ap(p≥5 is a twin prime)and some simple groups of the Lie type.In this paper,the authors continue this investigation.In particular,the authors show that the symmetric groups Sp+3,where p+2 is a composite number and p+4 is a prime and 97
相似文献
60.
Qiaoxia Liu Tu Liang Kuiyong Li Yanxiong Ke Yu Jin Xinmiao Liang 《Journal of separation science》2012,35(20):2685-2692
A stationary phase (named QA C10) with quaternary ammonium embedded between a propyl and a decyl chain was synthesized by immobilization of N,N‐dimethyldecylamine on chloropropyl–silica surface. A set of representative neutral, basic, and acidic compounds was employed to evaluate its chromatographic properties. The results illustrated that QA C10 was a mixed‐mode stationary phase possessing both hydrophobic and ionic characteristics. The QA C10 stationary phase was further used for selective separation of alkaloids from Cortex phellodendri. Under acidic condition, alkaloids could be eluted in first 8 min, while other neutral and acidic fractions were retained better on QA C10 column. Then, obtained alkaloid fraction was analyzed by LC‐MS/MS and 22 alkaloids were identified. Our study confirmed the advantages and application potential of the QA C10 stationary phase for alkaloids separation. 相似文献