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131.
Tetrakis(permethyl-beta-cyclodextrin)-modified zinc(II) porphyrin (1) and tetra(beta-cyclodextrin)-modified zinc(II) porphyrin (2) were synthesized via "click chemistry". Intermolecular inclusion complexation of these structurally similar 1 and 2 with tetrasodium tetraphenylporphyrintetrasulfonate (3) led to formation of two distinctly different nanoarchitectures with alternate porphyrin and cyclodextrin arrays, which were proven to be network and nanorod aggregates, respectively, by using transmission electron microscopy, atomic force microscopy, and scanning electron microscopy. From the results of comparative studies in different solutions, we elucidated the mechanisms that result in nanorod to network aggregates transition, concluding that the complexation strength of porphyrin with cyclodextrin is a crucial factor to activate the potential binding sites of a molecular building block. 相似文献
132.
Qiuyu Ding Zhen Lu Rui Zhao Longqiang Xiao Linxi Hou 《Journal of polymer science. Part A, Polymer chemistry》2024,62(9):1842-1852
Photo-induced reversible complexation-mediated polymerization (RCMP) is a green and economical method to prepare polymers with precise molecular weights, narrow molecular weight distributions and functionally active chain ends. Covalent organic frameworks (COFs) are a promising heterogeneous photocatalyst for mediating RCMP due to their adjustable structure, band gap, and porosity. In this work, 1,3,5-triformylphloroglucinol (Tp) and p-azoaniline (Azo) were selected to construct 2D β-ketoenamine linked Tp-Azo-COF as a heterogeneous photocatalyst to trigger RCMP under white light irradiation. A series of polymers with controllable molecular weight and narrow molecular weight distribution were successfully prepared by using Tp-Azo-COF as photocatalysis. On/off light experiments confirmed the good spatiotemporal control feature, and chain expansion experiments demonstrated the high “activity” of polymer chain ends. Furthermore, the mechanistic research elucidated that electron transfer between Tp-Azo-COF and initiator occurred, allowing the formation of reactive radicals to mediate RCMP. Density functional theory calculations revealed that the coordination of iodine on the initiator to catalyst obviously reduced the bond dissociation energy, leading to enhance in the polymerization rate. This work provides a platform for constructing heterogeneous photocatalysts with more efficient and stable to mediate RCMP. 相似文献
133.
Dong‐E Wang Feng Wang Xiang‐Gao Meng Yu Ding Li‐Li Wen Dr. Dong‐Feng Li Prof. Dr. She‐Ming Lan 《无机化学与普通化学杂志》2008,634(14):2643-2648
Three inorganic‐organic hybrid frameworks [Mn(HIMDC)(4,4′‐bipyo)0.5(H2O)]n (1) , [Cd(H2IMDC)2(2,2′‐bipyo)] (2) and [Ca(HIMDC)(H2O)2·H2O]n (3) (H3IMDC = 4,5‐imidazoledicarboxylate; 4,4′‐bipyo = 4,4′‐bipyridine‐N,N′‐dioxide; 2,2′‐bipyo= 2,2′‐bipyridine‐N,N′‐dioxide) have been hydrothermally synthesized and characterized by the elemental analyses, IR spectra, TG analysis and the single crystal diffraction. Both compounds 1 and 3 exhibit 2D layers while 2 is a monomer. It is noteworthy that compound 2 exhibits strong fluorescent emission in the solid state at room temperature. 相似文献
134.
Xiang-Zhu Wei Tian-Yu Ding Dr. Yang Wang Dr. Bing Yang Dr. Qing-Qing Yang Prof. Dr. Shengfa Ye Prof. Dr. Chen-Ho Tung Prof. Dr. Li-Zhu Wu 《Angewandte Chemie (International ed. in English)》2023,62(36):e202308192
High-valent iron-oxo species are appealing for conducting O−O bond formation for water oxidation reactions. However, their high reactivity poses a great challenge to the dissection of their chemical transformations. Herein, we introduce an electron-rich and oxidation-resistant ligand, 2-[(2,2′-bipyridin)-6-yl]propan-2-ol to stabilize such fleeting intermediates. Advanced spectroscopies and electrochemical studies demonstrate a high-valent FeV(O) species formation in water. Combining kinetic and oxygen isotope labelling experiments and organic reactions indicates that the FeV(O) species is responsible for O−O bond formation via water nucleophilic attack under the real catalytic water oxidation conditions. 相似文献
135.
PLD-assisted VLS growth of aligned ferrite nanorods, nanowires, and nanobelts-synthesis, and properties 总被引:4,自引:0,他引:4
Morber JR Ding Y Haluska MS Li Y Liu JP Wang ZL Snyder RL 《The journal of physical chemistry. B》2006,110(43):21672-21679
We report here a systematic synthesis and characterization of aligned alpha-Fe2O3 (hematite), epsilon-Fe2O3, and Fe3O4 (magnetite) nanorods, nanobelts, and nanowires on alumina substrates using a pulsed laser deposition (PLD) method. The presence of spherical gold catalyst particles at the tips of the nanostructures indicates selective growth via the vapor-liquid-solid (VLS) mechanism. Through a series of experiments, we have produced a primitive "phase diagram" for growing these structures based on several designed pressure and temperature parameters. Transmission electron microscopy (TEM) analysis has shown that the rods, wires, and belts are single-crystalline and grow along <111>m or <110>h directions. X-ray diffraction (XRD) measurements confirm phase and structural analysis. Superconducting quantum interference device (SQUID) measurements show that the iron oxide structures exhibit interesting magnetic behavior, particularly at room temperature. This work is the first known report of magnetite 1D nanostructure growth via the vapor-liquid-solid (VLS) mechanism without using a template, as well as the first known synthesis of long epsilon-Fe2O3 nanobelts and nanowires. 相似文献
136.
Ding S Dudley E Song Q Plummer S Tang J Newton RP Brenton AG 《Rapid communications in mass spectrometry : RCM》2008,22(6):766-772
Terpene lactones are a family of compounds with unique chemical structures, first recognised in an extract of Ginkgo biloba. The discovery of terpene lactone derivatives has recently been reported in more and more plant extracts and even food products. In this study, mass spectrometric characteristics of the standard terpene lactones in Ginkgo biloba were comprehensively studied using both an ion trap and a quadrupole time-of-flight (QTOF) mass spectrometer. The mass spectral fragmentation data from both techniques was compared to obtain the mass spectrometric fragmentation pathways of the terpene lactones with high confidence. The data obtained will facilitate the analysis and identification of terpene lactones in future plant research via the fragmentation knowledge reported here. 相似文献
137.
The sofid-state ECL behavior of a water-insoluble bis-cyclometalated (pq)2Ir(N-phMA) complex is presented, in which pq is a 2-phenylquinoline anion and N-phMA is N-phenyl methacrylamide, a monoanionic bidentate ligand. The MWNTs/(pq)2Ir(N-phMA) film, MWNTs/Ru(bpy)32+ film and (pq)2Ir(N-phMA) directly modified glassy carbon electrode were fabricated; only the MWNTs/(pq)2Ir(N-phMA) film can produce steady ECL in the presence of tri-n-propylamine as a coreactant. 相似文献
138.
Jianjun Zou Dingwei Wu Dawei Xiao Dan Qi Li Liu Li Ding Guangji Wang 《Chromatographia》2009,69(5-6):453-458
A sensitive and specific liquid chromatography–electrospray ionization–tandem mass spectrometry method has been developed and validated for the quantification of huperzine A in human plasma. After the addition of trimetazidine, the internal standard (IS) and sodium hydroxide, plasma samples were extracted using 5 mL ethyl acetate. The compounds were separated on an Agilent Zorbax SB C18 column (100 mm × 2.1 mm ID, dp 3.5 μm) using an elution system of 10 mM ammonium acetate solution–methanol–formic acid (18:82:0.1, v/v) as the mobile phase. The quantification of target compounds was obtained by using multiple reaction monitoring (MRM) transitions: m/z 243.1, 210.1 and 267.2, 166.0 were measured in positive mode for huperzine A and IS. Linearity was established for the range of concentrations 0.01–4.0 ng mL?1 with a coefficient of correlation (r) of 0.9991. The lower limit of quantification (LLOQ) was identifiable and reproducible at 0.01 ng mL?1. The method has been successfully applied to study the pharmacokinetics of huperzine A in healthy male Chinese volunteers. 相似文献
139.
The promotion effects of nickel catalyst of dry reforming with methane were extensively investigated by means of XRD, SEM, EDX, N2‐adsorption and H2‐adsorption. XRD characterization indicated that good dispersion of nickel oxide and MgO promoter is achieved over γ‐Al2O3 support. Addition of MgO promoter effectively retards the formation of NiAl2O4 phase. SEM and EDX analysis exhibited that the addition of rare‐earth metal oxide CeO2 effectively promotes the Ni metal dispersion on the surface of the catalysts despite of undesirable self‐dispersion of CeO2 promoter. Furthermore, the nickel component is gradually dispersed on the surface of the support following the exposure to reaction gas mixture for a period of time. The addition of MgO inhibited the self‐dispersion and promotion effect of CeO2 on Ni dispersion on the catalysts. H2 chemisorption revealed that the addition of the alkaline oxide MgO promoter significantly prohibits the metal dispersion on the catalyst. Inappropriate promoter addition can result in sharp decrease of the metal dispersion, N2‐adsorption indicated that oxide promoter was mostly concentrated on the outer layer of the alumina support while the nickel metal was generally dispersed in the support pores. Addition of promoters contributed to more reduction in mesopore volume. 相似文献
140.