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61.
The precise location of C C bonds in bioactive molecules is critical for a deep understanding of the relationship between their structures and biological roles. However, the traditional ultraviolet light-based approaches exhibited great limitations. Here, we discovered a new type of visible-light activated [2 + 2] cycloaddition of carbonyl with C C bonds. We found that carbonyl in anthraquinone showed great reactivities towards C C bonds in lipids to form oxetanes under the irradiation of visible-light. Combined with tandem mass spectrometry, this site-specific dissociation of oxetane enabled precisely locating the C C bonds in various kinds of monounsaturated and polyunsaturated lipids. The proof-of-concept applicability of this new type of [2 + 2] photocycloaddition was validated in the global identification of unsaturated lipids in a complex human serum sample. 86 monounsaturated and polyunsaturated lipids were identified with definitive positions of C C bonds, including phospholipids and fatty acids even with up to 6 C C bonds. This study provides new insights into both the photocycloaddition reactions and the structural lipidomics.A new visible-light activated [2 + 2] cycloaddition reaction was discovered and enabled pinpointing carbon–carbon double bonds in lipids. 相似文献
62.
协调政府与社会资本合作的利益分歧,进而实现个体理性向集体理性的趋同,这是纾解PPP项目合作困境的切入点之一。基于合作博弈理论,本文构建PPP项目非完全利益群体的合作形成机制,分析政府与社会资本间“合作共赢”的必要因素。研究表明,由政府与社会资本组成的PPP项目非完全利益群体,可在“理性-效用转移-有效协商”机制的协同作用下主动采取最优合作策略。其中,理性机制验证了政府与社会资本达成合作意向的前提,效用转移机制可实现二者之间的风险-收益对等,有效协商机制将达成政府与社会资本合作的帕累托均衡。 相似文献
63.
In this paper, a tumor immune model with time delay is studied. First, the stability of nonnegative equilibria is analyzed. Then the time delay τ is selected as a bifurcation parameter and the existence of Hopf bifurcation is proved. Finally, by using the canonical method and the central manifold theory, the criteria for judging the direction and stability of Hopf bifurcation are given. 相似文献
64.
65.
The chlorodibenzyltin dithiopiperidylcarbamate was synthesized by the reaction of dibenzyltin dichloride with dithiopiperidylcarbamate and was characterized by elemental analysis, IR and 1H NMR. The crystal structure was determined by X-ray single crystal diffraction. The crystallographic data are as follows: monoclinic, space group P21, a=0.63464(13)nm, b=1.9110(4)nm, c=0.87367(17)nm, β=97.67(3)°, Z=2, V=1.0501(4)nm3,Dc=1.571g·cm-3, μ=1.546mm-1, F(000)=500, R=0.0209, wR=0.0381 [I≥ 2σ(I)]. The str- uctures consist of discrete molecules containing five-coordinate tin atoms in a seriously distorted trigonal bipyramidal configuration. The molecules are packed in the unit cell in one-dimensional chain complex through a weak inter-action between the chlorine atom, the sulfur atom and one of the other sulfurs of an adjacent molecule. CCDC: 180034. 相似文献
66.
The title polymer was prepared from 5-diethylamino-3-thia-pentyl glycidyl ether anddiethylene glycol bisglycidyl ether via ring-opening copolymerization. It was found that thisreaction could be catalyzed by sodium, but not Lewis acid. The obtained polymer can coordinatewith platinum compound, and the platinum complex is a new kind of catalyst for thehydrosilylation of olefins with triethoxysilane. 相似文献
67.
Ye Gao YIN* Willis FORSLING Dan BOSTR諱 Oleg ANTZUTKIN Mats LINDBERG Alexander IVANOV Department of Chemistry Faculty of Science The University of Shantou Shantou Division of Inorganic Chemistry Department of Chemical Metallurgical Engineering Lule?University of Technology. Lule?se- Sweden Department of Chemistry Ume University Ume se-- Sweden 《中国化学快报》2003,14(2)
Owing to the particular affinity toward metal ion and changeable dentation, dialkyldithiophosphates are commonly used ligands in preparation of the transition metal complexes with variable structures1. For instances relevant to this work, the IIB metal complexes defined crystallographically so far have provided the examples as follows2-12 (Scheme 1). Scheme 1 The frameworks of IIB metal complexes of dialkyldithiophosphate MMMMMMMMMM a b c d … 相似文献
68.
A New Technique of Synthesizing 10—Hydroxy—5—methyl—5,10—dihydrophenophosphazine 10—Oxide 总被引:1,自引:0,他引:1
ZhiGangYIN DeFengZHAO 《中国化学快报》2003,14(4):347-350
10-Hydroxy-5-methyl-5,10-dihydrophenophosphazine 10-oxide(1)was prepared by a new technique of treating 10-methoxy-5,10-dihydrophenophosphazine 10-oxide(2)with an equivalent of NaH in anhydrous DMF,and then at 120℃ for 3-4h,which not only avoided poisonous and expensive methyl iodide used in literature,but made the consumption of NaH greatly decrease as well.The possible reaction mechanism was also described.The chemical structure of 1 was confiremed by IR,NMR,and mass spectroscopy. 相似文献
69.
70.
MoS2 nanotube coated SWNT (Single wall carbon nanotube) bundles have been successfully prepared by adsorbing (NH4)2MoS4 onto SWNT bundles and subsequent heat treatment under H2 at 900 ℃ in a tube furnace. The morphologies, structure and composition of the as-prepared sample were investigated by XRD, SEM, HRTEM coupled with EDS. The formation mechanism has also been preliminarily discussed. 相似文献