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1.
在富勒佛被合成后不久,Smalley等人就开始利用B、N、St等元素制备非碳富勒烯和骨架掺杂富勒烯的研究,合成出了骨架掺氮富勒佛一C59N,在质谱中观察到了微观量的骨架接棚富勒烯C。。B等[’-’],但迄今尚未见非碳富勒烯和骨架掺棚富勒烯宏观是合成的报导.用础部分取代富勒  相似文献   

2.
对3种电化学方法合成的新型结构富勒烯衍生物进行了激光质谱表征,确认了1,2加成以及[5,6]开环富勒烯衍生物结构.质谱结果发现了富勒烯以及富勒烯衍生物与氧的结合峰,核磁共振结果进一步证明了富勒烯衍生物的结构,为含有C60结构衍生物的研究提供了有力的表征手段.  相似文献   

3.
孙大勇  刘子阳 《分析化学》1997,25(6):663-666
采用解析电子轰击质谱对电弧法合成的稀土富勒烯衍生物的提取液进行了质谱分析,有效地检测到富勒烯,稀土富勒烯单电荷、双电荷的分子离子峰。利用同位素贡献确证了某些稀土富勒烯的生成。采用高电流瞬间解析样品,使得谱图中的谱峰强度更加真实地反应出提取液中各组分的相对含量。  相似文献   

4.
金属富勒烯的合成及结构研究是当前富勒烯化学研究的重要内容[1].一些稀土金属元素,如Sc[2]、Y[3]及大部分斓系元素(La、Ce、Nd、Sin、Eu、Gd、Tb、Ho)[4]形成的金属富勒烯已被合成出来.但仍有一些稀土富勒烯的合成尚未见报道,使人们难以对金属富勒烯的形成机制及物化性能作出全面的判断.本文采用原位活化、交换电极回放电弧放电及两步提取法首次得到含锡金属富勒烯.通过空白对比实验确定了Tin@C。怕9生成.对甲苯及毗院提取液的质谱研究表明含镀金属富勒烯具有区别于其它金属富勒烯的特殊的溶解性能,显示出其可能具有独特的…  相似文献   

5.
由冶金焦制备富勒烯的研究   总被引:2,自引:0,他引:2  
以冶金焦为原料用电弧法制备富勒烯,所得烟灰用甲苯索氏萃取。用质谱,高压液相色谱和紫外光谱技术表征富勒烯产品。研究了实验操作条件及冶金焦性质与富协烯产率间的关系。结果表明,粗富勒烯的产率及组成与资金焦的挥发分密切相关;冶金焦的挥发分愈高粗富勒烯的产率愈低。  相似文献   

6.
采用二硫化碳重结晶富勒烯混合物或二硫化碳二次抽提烟灰以提取高富勒烯(higherfulerenes,Cn,n>70)。产物经高效液相色谱分析,高富勒烯的含量从1%分别提高到4%和6%;经激光飞行时间质谱证明,产物中除含主要成分C60和C70以外,还含有C76、C78、C82、C84以及更高碳原子的富勒烯。  相似文献   

7.
中性富勒烯分子的直接电喷雾质谱分析   总被引:1,自引:0,他引:1  
电喷雾电离是新近发展的一种质谱技术, 适用于分析在溶液中呈离子状态的物质, 具有无碎片的特点。本文根据富勒烯分子的电子亲和性能, 将富勒烯混合物的甲苯溶液直接进行电喷雾质谱分析, 检出了C60, C70, C76, C80, C82, C84, C86,C88, C90, C92, C94和C96等的负离子峰。并用萘钾作还原剂,将富勒烯混合物预先还原, 制得富勒烯负离子溶液后再作电喷雾质谱分析, 得到相同的结果。表明各类富勒烯分子在电喷雾过程中俘获电子的能力与被萘钾还原的能力相一致。  相似文献   

8.
首次利用富勒烯谷氨酸苄酯的游离氨基引发谷氨酸苄酯-NCA开环聚合,得到了一种新的富勒烯封端的聚谷氨酸苄酯.利用核磁共振(1HNMR)、红外光谱、紫外可见光谱、基质辅助激光解吸电离飞行时间质谱(MALDI-TOF-MS)和热重分析等对产物进行了表征.  相似文献   

9.
高富勒烯的含量很低,在总的富勒烯混合物中仅点1%左右,将其分离出来一般要经过提取、富集、高效液相色谱分离三个步骤。目前,高富勒烯的富集用得较多是Diederich等采用的方法[1~4],他们将富勒烯混合物在三根中性氧化铝柱中,用正己烷和甲苯(95/5...  相似文献   

10.
电喷雾电离质谱在富勒烯化学中的应用进展   总被引:2,自引:0,他引:2  
电喷才电离质谱(ESI-MS)是本世纪发展的一种非常重要的质谱,具有软电离、无碎片的特点,可用于分析检测非挥发性的,极性的、热不稳定的化合物,在富勒烯化学研究中起了重要作用。本文对ESI-MS在富勒烯化学中的应用进展作一概要评述。  相似文献   

11.
应用气相色谱-质谱法(GC-MS)研究了光促进温和条件下环己烯与CO2羰基化反应中与丙酮有关的副产物,这有助于对反应进行深入的研究和优化。在光促进温和条件下环己烯与CO2进行羰基化反应的同时,环己烯也可以与反应体系中的CH3COCH3发生光化学反应,生成副产物。分别用CH3COCH3和CD3COCD3进行实验,对反应产物进行GC-MS分析,通过对不同反应情况下的MS图中同位素效应的比较,可以分析出副产物中是否有来自CH3COCH3中的—CH3。研究表明丙酮与底物环己烯之间生成了环氧丁烷衍生物、cyclo-C6H9-C(CH3)2OH和cyclo-C6H11-C(CH3)2OH等3种副产物。  相似文献   

12.
氮气氛中合成杂氮球烯、碳纳米管及纳米晶体的研究詹梦熊,余荣清,王育煌,杨士姚,程大典,刘朝阳,郑兰荪(厦门大学化学系,厦门,361005)关键词杂氮球烯,碳纳米管,纳米晶体,氮气氛自球烯及碳纳米管常规制备方法问世以来[1,2],制备方法的改进一直成为...  相似文献   

13.
煤沥青成分极其复杂,其中含有分子量较大的多环芳烃及其氧化产物等组分。不同来源的原料煤及生产工艺得到的煤沥青在芳构化程度、组成、性质、分子结构等方面皆差别很大。该文分别采用气相色谱-质谱(GC-MS)、裂解/气相色谱-质谱(Py/GC-MS)和高效液相色谱(HPLC)手段,为煤沥青指纹图谱库的构建发展了普适、稳定、简单的分析方法。在GC-MS方法中采用常用的HP-5MS柱,在线性温度梯度条件下分析,得到33个组分的色谱图,方法对不同样品的稳定性良好。采用裂解/气相色谱-质谱方法研究探讨了较高温度下组分结构和组成的变化,对于沥青产品的加工以及老化研究具有借鉴意义。在HPLC方法建立过程中,采用最常用的C_(18)柱反相色谱分离模式,以甲醇/水为流动相,在线性梯度条件下建立方法,针对不同样品可以得到41个组分的稳定色谱峰。基于该文的方法,可为进一步建立煤沥青的指纹谱图库,以及进一步完善煤沥青的评价方法,开发煤沥青的新用途提供理论基础数据。  相似文献   

14.
王贤纯  梁宋平 《分析化学》2004,32(9):1219-1222
利用RP—HPLC/ESI—MS直接分析用芴甲氧羰基(Fmoc)固相多肽合成方法在PHB树脂上偶联合成的一个七肽(H2N—Tyr—Val—Asn-Thr-Asn—Met—Gly—COOH,Mr797.3)粗产物。RP—HPLC显示合成粗产物含有1个主成分,4个次要成分和多个微量成分;与之联用的电喷雾质谱则同步准确地测定出各成分的分子量(m/z)并自动对各主要成分的化学结构进行了串联质谱分析。结果证明,粗产物中的主成分即为目标七肽,另外几个主要副产物为七肽的氧化产物或残缺肽。  相似文献   

15.
Soot (sometimes referred to as black carbon) is produced when hydrocarbon fuels are burned. Our hypothesis is that polynuclear aromatic hydrocarbon (PAH) molecules are the dominant component of soot, with individual PAH molecules forming ordered stacks that agglomerate into primary particles (PP). Here we show that the PAH composition of soot can be exactly determined and spatially resolved by low‐fluence laser desorption ionization, coupled with high‐resolution mass spectrometry imaging. This analysis revealed that PAHs of 239–838 Da, containing few oxygenated species, comprise the soot observed in an ethylene diffusion flame. As informed by chemical graph theory (CGT), the vast majority of species observed in the sampled particulate matter may be described as benzenoids, consisting of only fused 6‐membered rings. Within that limit, there is clear evidence for the presence of radical PAH in the particulate samples. Further, for benzenoid structures the observed empirical formulae limit the observed isomers to those which are nearly circular with high aromatic conjugation lengths for a given aromatic ring count. These results stand in contrast to recent reports that suggest higher aliphatic composition of primary particles.  相似文献   

16.
Although all fullerenes do not satisfy the classical aromaticity condition, as a result of their nonplanar nature, they experience effective stabilization due to extensive cyclic π-electron delocalization and exhibit pronounced "spherical aromaticity". This feature has raised the question of the opposite phenomenon, that is, the existence of antiaromatic carbon cages. Here the first experimental evidence of the existence of antiaromatic fullerenes is reported. The elusive (#6094)C(68) was effectively captured as C(68)Cl(8) by in situ chlorination in the gas phase during radio-frequency synthesis. The chlorinated cage was separated by means of multistage HPLC, and its connectivity unambiguously determined by single-crystal X-ray analysis. Halogen-stripped pristine (#6094)C(68) was monitored by mass spectrometry of the chlorinated C(68)Cl(8) cage. Quantum chemical calculations reveal the highly antiaromatic character of (#6094)C(68), in accordance with all geometric, energetic, and magnetic criteria of aromaticity. Chlorine addition leads to substantial stabilization of the cage owing to aromatization in the resulting C(68)Cl(8), which explains its high abundance in the primary fullerene soot. This work provides new insights into the process of fullerene formation and better understanding of aromaticity phenomena in general.  相似文献   

17.
The smallest fullerene to form in condensing carbon vapor has received considerable interest since the discovery of Buckminsterfullerene, C(60). Smaller fullerenes remain a largely unexplored class of all-carbon molecules that are predicted to exhibit fascinating properties due to the large degree of curvature and resulting highly pyramidalized carbon atoms in their structures. However, that curvature also renders the smallest fullerenes highly reactive, making them difficult to detect experimentally. Gas-phase attempts to investigate the smallest fullerene by stabilization through cage encapsulation of a metal have been hindered by the complexity of mass spectra that result from vaporization experiments which include non-fullerene clusters, empty cages, and metallofullerenes. We use high-resolution FT-ICR mass spectrometry to overcome that problem and investigate formation of the smallest fullerene by use of a pulsed laser vaporization cluster source. Here, we report that the C(28) fullerene stabilized by encapsulation with an appropriate metal forms directly from carbon vapor as the smallest fullerene under our conditions. Its stabilization is investigated, and we show that M@C(28) is formed by a bottom-up growth mechanism and is a precursor to larger metallofullerenes. In fact, it appears that the encapsulating metal species may catalyze or nucleate endohedral fullerene formation.  相似文献   

18.
We present follow-up studies on the formation mechanism of fullerene molecules from random ensembles of C2 molecules using quantum chemical molecular dynamics. Two possible roadmaps are investigated as to how buckminsterfullerene C60 and higher fullerenes could be formed. In a "size-up" scenario, fullerenes of the cage size of C72-C96 were found to form directly from high concentrations of C2 molecules at 2000 K with periodic supply of batches of additional C2's. In a "size-down" approach, smaller fullerenes are sometimes formed by losing carbon fragments in "fall-off" or "pop-out" annealing processes under prolonged heating of giant fullerenes, which were self-assembled at initial stages from C2's with lower concentrations. Both roadmaps are found to provide explanations for the appearance of C60 and larger fullerenes in combustion and carbon arc experiments.  相似文献   

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