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1.
通过直接进样方式,采用电喷雾电离质谱技术分析了8个合成的富勒烯-N-甲基吡咯烷衍生物,详细研究了其在电喷雾条件下的质谱行为。由结果可知,该类化合物在电喷雾电离过程中易得到电子而负离子化;当衍生物结构中有相对易质子化基团或有活泼氢时,则可获得质子化和去质子的正负离子谱图;衍生物在负离子模式下容易失去吡咯环产生富勒烯负离子,且在合适能量碰撞下易发生衍生化基团内部的逆环加成反应,通过失去1个中性小分子物质CH2‖N—CH3,产生新的一取代亚甲基富勒烯衍生物。基于电喷雾电离源技术联合离子阱分析器建立的质谱分析方法,不但能提供准确的分子量信息,还能通过获得高分辨同位素谱峰和丰富的二级碎片离子峰,进一步确认化合物的分子结构,是一种先进、快速的富勒烯吡咯烷衍生物定性分析方法。  相似文献   

2.
论述了用激光解吸电离谱法分析富勒烯。因在电离过程中富勒分子不发生裂解,因此这种方法可直接用于富勒烯混合物的分析而勿需任何预分离。还给出了用本法分析较大、较稳定富勒烯分子的质谱图。  相似文献   

3.
阿屈酸的极性很强且热稳定性很差,因此不适合用电子轰击质谱来研究,该文研究了它的正离子和负离子电喷雾质谱的行为,结果表明阿屈酸既可作负离子电喷雾质谱分析,也可作正离子电喷雾质谱分析,且正离子电喷雾质谱分析的灵敏度高于负离子;电喷雾源内碰撞诱导解离分析时正离子和负离子的裂解方式相似,但不完全相同,且正离子有明显的[M Na]^ 峰和[M H]^ 及[M Na]^ 与M的非共价键簇离子峰,这对确定类似未知物的相对分子质量有很大的帮助。  相似文献   

4.
脱水淫羊藿素的电喷雾多级串联质谱研究   总被引:1,自引:0,他引:1  
窦建鹏  刘志强  刘淑莹 《分析化学》2003,31(12):1433-1436
研究了脱水淫羊藿素的电喷雾质谱行为,结果表明:该化合物在正、负离子模式下,均可得到较好的电喷雾质谱信息,且在负离子模式下电喷雾质谱分析的灵敏度较高;运用电喷雾碰撞诱导解离技术,发现正离子和负离子模式下的裂解方式虽有相似之处但并不完全相同;分别阐明了该化合物在正、负离子模式下的电喷雾质谱碎裂规律。  相似文献   

5.
郑岩  王英武  周慧  顾景凯 《分析化学》2004,32(2):183-186
在分析青霉素类药物负离子质谱裂解规律中,应用电喷雾四级杆飞行时间质谱(ESI-QqTOF MS),利用质谱的高分辨能力获得丰富的碎片离子信息,证实了一些裂解过程推测的正确性,得出了青霉素类药物在负离子质谱条件下裂解规律:β-内酰胺环在C(6)-C(7)和N(1)-C(5)处断裂;侧链上的C-N键在合适的条件下有可能发生断裂。  相似文献   

6.
电喷雾质谱在非共价生物—有机分子复合物研究中的应用   总被引:5,自引:0,他引:5  
孙维星  刘志强 《分析化学》1998,26(1):111-116
大量实验证明能够准确测定生物大分子分子量(20,000Da)的电喷雾质谱在分析溶液中生物化学作用方面有着巨大的潜力。本文综述了电喷雾质谱在分析液中特异性非共价生物-有机分子复合物方面的应用。  相似文献   

7.
车前草中苯乙醇苷化合物的电喷雾多级串联质谱研究   总被引:4,自引:0,他引:4  
利用电喷雾多级串联质谱技术研究了车前草药材中的苯乙醇苷化合物, 根据其在负离子条件下表现出的特征质谱行为, 提出了车前草中的苯乙醇苷类化合物可能的电喷雾质谱碎裂规律, 建立了车前草中苯乙醇苷化合物的快速分析、鉴定方法.  相似文献   

8.
淫羊藿苷的电喷雾质谱研究   总被引:4,自引:0,他引:4  
研究了淫羊藿苷的电喷雾质谱行为.结果表明,该化合物在正、负离子模式下均可得到较好的质谱信息,在负离子模式下,采用H/D交换方法,证明淫羊藿苷易形成加合2个水分子的准分子离子.利用电喷雾碰撞诱导解离方法,分别阐明了该化合物在正、负离子模式下的电喷雾质谱碎裂规律.  相似文献   

9.
电喷雾电离质谱在化学中应用新进展   总被引:11,自引:0,他引:11  
魏先文  徐正 《有机化学》1999,19(1):97-103
电喷雾电离质谱(ESI-MS)是本世纪发展的非常重要的质谱,具有无碎片的特点,可分析检测非挥发性的、极性的、热不稳定的化合物。评述了ESI-MS在富勒烯化学、无机配合物、簇合物、有机化学反应,金属有机化合物及超分子化学中的应用进展。  相似文献   

10.
芍药苷的电喷雾串联质谱研究   总被引:7,自引:1,他引:7  
采用电喷雾串联质谱(ESI-MSn)技术, 结合H/D交换方法, 在正、负离子检测模式下对白芍药材中主要成分芍药苷的质谱裂解规律进行了系统研究. 实验结果表明, 该化合物在正、负离子模式下均得到较好的质谱信息, 且在正离子模式下, 电喷雾质谱分析的灵敏度更高. 同时获得了其质谱裂解规律, 为白芍中其它化合物的分析鉴定提供了有效的质谱方法.  相似文献   

11.
A soluble hybrid nanomaterial that combines fullerenes and carbon nanohorns (CNHs) has been prepared and fully characterized. Electrochemical investigations revealed that the CNHs modify the electron accepting ability of C(60) in the hybrid material.  相似文献   

12.
Isoxazolino[4,5:1,2][60]- and -[70]fullerenes undergo an efficient retro-cycloaddition reaction to pristine fullerene by thermal treatment in the presence of an excess of a dienophile and Cu(II) catalysis, which can be selectively used in the presence of malonate or pyrrolidine cycloadducts. Trapping experiments using N-phenylmaleimide as dipolarophile have shown that the reaction mechanism occurs by thermal removal of the nitrile oxide 1,3-dipole, in a process which is favored by the presence of Cu(II) as the catalyst. The ESI-MS study supports the observed retro-cycloaddition process for both C60 and C70 derivatives. In contrast to previous electrochemical retro-cycloaddition processes observed in fulleropyrrolidines, isoxazolinofullerenes were stable under oxidative conditions.  相似文献   

13.
报道了C60与1,3-丙二胺和N,N-二甲基-1,3-丙二胺的加合反应,反应产物未经预先离子化处理直接用ESL-MS进行检测。由于反应产物从甲苯溶液中析出,避免了生成多胺基加合物,产物以单加成物为主。当加合反应在空气氛下进行时,有加合氧的产物C60On(NH2—CH2CH2CH2NR2)m(R=H,CH3)存在。实验发现:N,N-二甲基-1,3-丙二胺比1,3-丙二胺更容易与C60发生多胺基加成和氧加成反应。通过控制反应条件可制备C60二胺的单加成产物。  相似文献   

14.
Photosensitized electron-transfer processes of fullerenes hybridized with electron donating or other electron accepting molecules have been surveyed in this review on the basis of the recent results reported mainly from our laboratories. Fullerenes act as photo-sensitizing electron acceptors with respect to a wide variety of electron donors; in addition, fullerenes in the ground state also act as good electron acceptors in the presence of light-absorbing electron donors such as porphyrins. With single-wall carbon nanotubes (SWCNTs), the photoexcited fullerenes act as electron acceptor. In the case of triple fullerene/porphyrin/SWCNT architectures, the photoexcited porphyrins act as electron donors toward the fullerene and SWCNT. These mechanisms are rationalized with the molecular orbital considerations performed for these huge supramolecules. For the confirmation of the electron transfer processes, transient absorption methods have been used, in addition to time-resolved fluorescence spectral measurements. The kinetic data obtained in solution are found to be quite useful to predict the efficiencies of photovoltaic cells.  相似文献   

15.
金属富勒烯的质谱研究   总被引:1,自引:0,他引:1  
利用电孤放电法合成笼内金属富勒烯Gd@C82,Gd2@C80,实验结果表明,两步高温高压法(1,2,4-三甲基苯,吡啶)可有效地提取金属富勒烯Gd@C82.本文分别利用ESI-MS,REC-MS,MALDI-TOF-MS质谱技术研究了Gd@C82,Gd2@C80,Gd@C80和富勒烯Cn(n=60,70,82,84…)的气相负离子特性。结果表明,包人Gd^3 后非极性的C82转变为极性的Gd@C82分子;金属离子Gd^3 处于C82^3-笼中非中心的位置。  相似文献   

16.
煤基富勒烯烟灰萃取产物的质谱分析   总被引:2,自引:0,他引:2  
用甲苯等有机溶剂对由煤制得烟灰(soot)进行索氏萃取,用时间飞行质谱及气相色谱-质谱联用(GCMS)技术对所得的萃取产物进行了分析,结果发现,煤基粗富勒烯中除含有大量的C60和C70外,高碳富勒烯(如C74、C78,C82、C84、C100及C106等)的丰度也较高。在煤基粗富勒烯的伴生副产物中存在一些含有苯环结构的芳香性碳氢化合物和少量的长烷烃化合物,由此推测煤基富勒烯的形成过程可能遵循着一条与以石墨为原料时的机制完全不同的途径。  相似文献   

17.
Photosensitized electron-transfer processes of nanocarbon materials hybridized with electron donating or electron accepting molecules have been surveyed in this tutorial review on the basis of the recent results reported mainly from our laboratories. As nano-carbon materials, fullerenes and single wall carbon nanotubes (SWCNTs) have been employed. Fullerenes act as photo-sensitizing electron acceptors with respect to a wide variety of electron donors; in addition, the fullerenes act as good ground state electron acceptors in the presence of light-absorbing electron donors such as porphyrins and phthalocyanines. In the case of SWCNTs, their ground states act as electron acceptor and electron donors, depending on the photosensitizers. For example, with respect to the photoexcited porphyrins and phthalocyanines, SWCNTs usually act as electron acceptors, whereas for the photoexcited fullerenes, SWCNTs act as electron donors. The diameter sorted semi-conductive SWCNTs have been used to verify the size-dependent electron transfer rates. For the confirmation of the electron transfer processes, the transient absorption methods have been widely used, in addition to the time-resolved fluorescence spectral measurements. The kinetic data thus obtained in solution are found to be quite useful to predict the efficiencies of photovoltaic cells constructed on semiconductor nanoparticle modified electrodes and their photocatalytic processes.  相似文献   

18.
利用对叔本基杯「8」芳烃对烟炱中C60的选择性配合作用 烟炱邻二氯苯(ODCB)提取筘的高碳成份得到富集,用高效液相色谱(HPLC)分离,得到C70,C76,C78,C84和五种高碳富勒烯及相应的UV-Vis光谱,实验中发现,ODCB提取物中C78的比例与其它溶剂提取物略有差别,富勒烯的保留时间的对数与富勒烯的碳原子数之间的良好的线性关系,随着富勒烯对称性的降低,UV-Vis光谱吸收极值增多,谱带  相似文献   

19.
Ionic liquids are suitable media which stabilize charged intermediates favoring those mechanisms that occur through charge separation. We have used ionic liquids to develop a photocatalytic system to perform the reduction of a carbonyl group to alcohol, thus mimicking the behavior of the reductase enzymes. The photochemical cycle is based on the well-known electron transfer from the Ru(bpy)(3)2+ complex in its excited state, acting as electron donor to MV2+, which acts as electron acceptor. The initial electron transfer process can be promoted upon selective Ru(bpy)(3)2+ excitation by visible light. By means of laser flash photolysis we have provided evidence of the nature and lifetimes of the intermediates involved in the photocatalytic system. Thus, the initial electron transfer between Ru(bpy)(3)2+ triplets and viologen MV2+ forms the MV*+ radical cation, which upon accepting an H* atom from a suitable hydrogen atom donor, forms the corresponding dihydropyridine MVH+ reducing agent.  相似文献   

20.
The reaction between a bulky N-heterocylic carbene (NHC) and C(60) leads to the formation of a thermally stable zwitterionic Lewis acid-base adduct that is connected via a C-C single bond. Low-energy absorption bands with weak oscillator strengths similar to those of n-doped fullerenes were observed for the product, consistent with a net transfer of electron density to the C(60) core. Corroborating information was obtained using UV photoelectron spectroscopy, which revealed that the adduct has an ionization potential ~1.5 eV lower than that of C(60). Density functional theory calculations showed that the C-C bond is polarized, with a total charge of +0.84e located on the NHC framework and -0.84e delocalized on the C(60) cage. The combination of reactivity, characterization, and theoretical studies demonstrates that fullerenes can behave as Lewis acids that react with C-based Lewis bases and that the overall process describes n-doping via C-C bond formation.  相似文献   

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