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131.
氯代甲苯双电荷离子的单分子解离反应研究 总被引:1,自引:0,他引:1
研究了在70 eV电子轰击电离条件下,氯代甲苯及氯化苄产生的双电荷离子[C_7H_7Cl]~(2+)、[C_7H_6Cl]~(2+·)和[C_7H_5Cl]~(2+)为母体的两种类型单分子解离反应.主要讨论了亚稳双电荷离子的异构化反应、失H解高的“偶电子规则”以及单分子电荷分离过渡态的结构. 相似文献
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Liu L Qiu S Wang B Zhang W Lu P Xie Z Hanif M Ma Y Shen J 《The journal of physical chemistry. B》2005,109(49):23366-23370
We have investigated the thermal degradation in air by Fourier transform infrared spectroscopy of a ladder-type copolymer containing fluorene units in the backbone (Me-LPF), to reveal the formation of the ketonic defects. As thermal treatment of Me-LPF film at 200 degrees C in air proceeds, a new group of complex absorption bands due to degradation products arises in the range between 1800 and 1600 cm(-1). The observed overlapping bands were separated and assigned by utilizing the second-derivative IR spectral analysis, which can narrow the peak width to one-third of the originals and thereby eases the analysis. The degraded products were assigned as fluorenone (1718 cm(-1)) and benzophenone (Ar-(C=O)-Ar) (1665 cm(-1)), formed by the oxidation of the backbone, and acylphenone (Ar-(C=O)-R) (1685 cm(-1)) from the side chain. The fluorenone was found to be the major component among the degraded products in the main chain, and the time and temperature dependence indicated that the oxidation is a kind of autocatalytic radical-chain process. The oxidation can reach a very high degree (approximately 30% for 6 h oxidation at 240 degrees C estimated by absorption of the alkyl). Our results suggest the possibility of the oxidation of the 9-bialkylfluorene sites. We propose that the degradation of the alkyl in the side chain can help the radicals to propagate in the chain reaction. 相似文献
135.
The additive Pummerer reaction of several heteroaromatic sulfilimines has been investigated. The overall process involves the reaction of the sulfilimine with TFAA to produce a transient N-tosyl-N-trifluoroacetyl sulfonium ion. Nucleophilic attack at the adjacent vinyl carbon results in the ejection of the sulfonamide group and the resulting thionium ion loses a proton to give the observed product. 相似文献
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Fang Q Zhu G Xue M Sun J Tian G Wu G Qiu S 《Dalton transactions (Cambridge, England : 2003)》2004,(14):2202-2207
Four three-dimensional non-interpenetrating open coordination frameworks constructed from the CTC ligand (CTC =cis,cis-1,3,5-cyclohexanetricarboxylate) coordinated to metal ions (Mn(II) and Cd(II)): Mn(3)(CTC)(2)(DMF)(2)(1); Cd(3)(CTC)(2)(H(2)O)(3).H(2)O (2); Cd(3)(CTC)(2)(4,4'-bpy)(2)(EG)(2)(3); Cd(3)(CTC)(2)(mu(2)-hmt)(DMF)(C(2)H(5)OH)(H(2)O).2H(2)O (4)(DMF = dimethylformamide and EG = ethylene glycol) have been synthesized by slow evaporation of DMF-C(2)H(5)OH-H(2)O solutions of M(II)(Mn(II) or Cd(II)) and CTC in the presence of the organic bases TEA (triethylamine), TEA, 4,4'-bpy (4,4'-bipyridine) and hmt (hexamethylenetetramine), respectively, and structurally characterized by X-ray crystallography. The polymer constructed by CTC and Mn(II) exhibits a 3-D architecture with 5 x 9 A channels; the polymer formed by CTC and Cd(II) exists a 3-D extended framework with 9 x 9 A channels; wave-like sheet subunits of the polymer are upheld by 4,4'-bpy ligands resulting in a 3-D framework with 4 x 10 A channels; two-fold alternate sheet subunits of the polymer are interlinked by mu(2)-hmt ligands to form a novel 3-D architecture with 7 x 8 A channels. Polymers exhibit their strongest excitation peaks at 391, 390 and 394 nm, respectively, and their main strong emission peaks are at 543, 460 (with a shoulder peak at about 570 nm) and 557 nm, respectively. 相似文献
138.
Zou B Wang M Qiu D Zhang X Chi L Fuchs H 《Chemical communications (Cambridge, England)》2002,(9):1008-1009
Stable surface nanostructures with different morphology have been successfully constructed by modifying the chemical structure of synthetic amphiphiles; by introducing mesogenic groups into bolaform amphiphiles, stable spaghetti-like or stripe-like nanostructures can be obtained; it is believed that such a kind of surface structure could be used for templating synthesis and assembly. 相似文献
139.
Michael Woolman Jimmy Qiu Claudia M. Kuzan-Fischer Isabelle Ferry Delaram Dara Lauren Katz Fowad Daud Megan Wu Manuela Ventura Nicholas Bernards Harley Chan Inga Fricke Mark Zaidi Brad G. Wouters James T. Rutka Sunit Das Jonathan Irish Robert Weersink Howard J. Ginsberg David A. Jaffray Arash Zarrine-Afsar 《Chemical science》2020,11(33):8723
Integration between a hand-held mass spectrometry desorption probe based on picosecond infrared laser technology (PIRL-MS) and an optical surgical tracking system demonstrates in situ tissue pathology from point-sampled mass spectrometry data. Spatially encoded pathology classifications are displayed at the site of laser sampling as color-coded pixels in an augmented reality video feed of the surgical field of view. This is enabled by two-way communication between surgical navigation and mass spectrometry data analysis platforms through a custom-built interface. Performance of the system was evaluated using murine models of human cancers sampled in situ in the presence of body fluids with a technical pixel error of 1.0 ± 0.2 mm, suggesting a 84% or 92% (excluding one outlier) cancer type classification rate across different molecular models that distinguish cell-lines of each class of breast, brain, head and neck murine models. Further, through end-point immunohistochemical staining for DNA damage, cell death and neuronal viability, spatially encoded PIRL-MS sampling is shown to produce classifiable mass spectral data from living murine brain tissue, with levels of neuronal damage that are comparable to those induced by a surgical scalpel. This highlights the potential of spatially encoded PIRL-MS analysis for in vivo use during neurosurgical applications of cancer type determination or point-sampling in vivo tissue during tumor bed examination to assess cancer removal. The interface developed herein for the analysis and the display of spatially encoded PIRL-MS data can be adapted to other hand-held mass spectrometry analysis probes currently available.Integration between a hand-held mass spectrometry desorption probe based on picosecond infrared laser technology (PIRL-MS) and an optical surgical tracking system demonstrates in situ tissue pathology from point-sampled mass spectrometry data. 相似文献
140.
煤粉在热分解过程中比表面积和孔隙结构的变化 总被引:17,自引:7,他引:17
用氮气等温吸附(77K)方法测量了四种不同煤粉在热分解过程中的BET比表面积和孔隙结构。结果表明,不同煤种的比表面积在热分解过程中其变化有着相似的规律。在热分解温度低于500℃时,煤粉所释放的挥发份主要来自煤粒外表面。当热分解温度高于500℃后,煤粉释放出的挥发份主要来自煤粒内部深处。在800℃时,由于煤的塑性,煤粒的部分孔减小和关闭,使其比表面积以及孔隙明显减少。在热分解温度高于850℃后,煤粉的比表面积随温度升高而急剧增大。 相似文献