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1.
C60和C70的分子及晶体结构   总被引:1,自引:0,他引:1  
本文较详细地介绍了C60、C70的各种光谱、波谱、X射线衍射结果及C60、C70单晶体的培养方法,说明了C60、C70的分子构型及晶体结构和相变特点。  相似文献   

2.
C1化学   总被引:2,自引:0,他引:2  
以CO/H2、CH3OH、CH4、CO2为主要原料的C1化学,将在本世纪末或下世纪初兴起,发展C1化学可以缓解日趋枯褐的石油资源危机,延续人类不可缺少的能源及化工生产。本文概述了C1化学的发展现状及研究方向,展现了C1化学的基本框架。同时,还从能源、资源、经济、生态等方面论述了发展C1化学的重要意义:未来的世界必须发展C1化学,C1化学必将为未来世界造福。  相似文献   

3.
C_(60)、C_(70)与过氧苯甲酰反应的动力学研究胡波,薛万华,张法义,尚振锋,马克勤,臧雅茹,赵学庄(南开大学化学系,天津,300071)关键词C_(60),C_(70),动力学Kratschmer等人[1]的发现使制备宏观量的C(60)和C(70...  相似文献   

4.
用量子化学从头算方法研究了C40、Nb@C40^+,La^@C40^+的几何构型和电子结构,C40最稳定构型具有D2对称性。La和N原子内含于C40笼中,形成金属夹心碳笼Nb@C40^+、La@C40^+。C40结合能大于M@C40^+(M=Nb,La)。  相似文献   

5.
球烯-C_(60)和C_(70)的纸制模型曹玲华,刘育亭(新疆大学化学系830046)球烯-C60和C70是具有固定组成和特殊结构的碳素多面体原子簇,是继金刚石和石墨之后,新发现的碳的同素异形体[1,2]。由于它特殊的结构和形态,已引起人们高度的重视。...  相似文献   

6.
B4C2,B2C4簇的从头算研究   总被引:3,自引:2,他引:3  
用量子化学从头计算方法研究了B4C2,B2C4簇各种可能的几何构型,计算了相应的振动光谱。B4C2的稳定构型除直线,平面构型外还有三维模型,而B2C4的稳定构型均为直线、平面构型,因此,B4C2与B6接近,B2C4与C6接近。B-C和C-C多重键及强共轭效应是B4C2和B2C4簇稳定的重要因素。  相似文献   

7.
富勒烯C60/C70的制备化学   总被引:4,自引:0,他引:4  
评价了富勒烯制备化学的研究与进展,阐述了未来工业规模生产富勒烯的发展动向与前景,着重对有机合成制备C60的研究进行了探讨。  相似文献   

8.
C60与聚苯乙烯活性种的反应   总被引:2,自引:0,他引:2  
C_(60)与聚苯乙烯活性种的反应汪长春,潘宝荣,府寿宽(复旦大学高分子科学系,上海,200433)关键词高分子C_(60)衍生物,聚苯乙烯阴离子活性种,C_(60)自从C60被常规量制备出以后[1]许多C60的衍生物也已合成出来。研究发现,C60及其?..  相似文献   

9.
本文用紧束缚法的EHMO三维晶体轨道程序进行计算求得了C60,K3C60和K6C60的能带结构,并得到了一系列过去未曾见过报导的原子投影态密度、轨道、原子重叠布据、原子电荷、轨道矢量等数据。从这些能带图中可以充分说明三种物质的区别,并可解释K3C60的超导性和C60与K6C60的绝缘性。  相似文献   

10.
C_(60)硫衍生物──C_(60)S~+的气相合成刘子阳,郝国仑,郭兴华,刘淑莹(中国科学院长春应用化学研究所,长春,130022)关键词C_(60),CS_2,离子-分子反应自实现C(60)的宏观量合成以来[1],通过将C(60)进行化学衍生进而改变?..  相似文献   

11.
The coupling of organolithium reagents, including strongly hindered examples, at cryogenic temperatures (as low as −78 °C) has been achieved with high-reactivity Pd-NHC catalysts. A temperature-dependent chemoselectivity trigger has been developed for the selective coupling of aryl bromides in the presence of chlorides. Building on this, a one-pot, sequential coupling strategy is presented for the rapid construction of advanced building blocks. Importantly, one-shot addition of alkyllithium compounds to Pd cross-coupling reactions has been achieved, eliminating the need for slow addition by syringe pump.  相似文献   

12.
9-Substituted carbazoles are widely used units in materials science, and their oxidative reactions have been utilized for the synthesis and characterization of polymers. Though the oxidative mechanism of carbazoles has been known for a few decades, structural definition has remained difficult, because their polymers are generally insoluble with incomplete characterization and unknown dependence of the electrochemical potentials. The oxidative reactions of 9-substituted carbazoles should be carefully considered under specific oxidative conditions; otherwise, structure definitions could be wrong, because the IR and NMR spectra used previously cannot quantitatively analyze 3,3′-coupling and 6,6′-coupling of carbazoles. In this review, the best understanding of the C3−C3′ and C6−C6′ oxidative couplings of 9-substituted carbazoles is presented, and the benefit of these oxidative reactions from the viewpoints of electrochemical synthesis, film engineering, and the synthesis and processing of polymers is highlighted.  相似文献   

13.
A numerical simulation was done to check the possibility of using planar C/C/C multilayers with density contrast 0.2 and 0.7 g/cm3 as an X-ray waveguide. After an optimization procedure, suitable waveguide layer thicknesses were found which provide a high degree of resonant standing wave field intensity enhancement in the core layer at incident beam energy of 13 keV. The obtained results were compared with those of the Mo/Be/Mo waveguide, whose high waveguiding capability at the same energy value was reported in the 1990s. The comparison shows that standing wave field intensity resonant enhancement provided by C/C/C planar multilayers is very high and, consequently, a guided beam can be well detected.  相似文献   

14.
Reaction of red phosphorus with RfI in a 1:2 molar ratio at 230 degrees C led to the formation of a mixture of (Rf)2PI and (Rf)PI2 (Rf = C6F13, C7F15, C8F17) in about a 70:30 ratio, respectively. These mixtures were separated by vacuum distillation. (Rf)2PI (Rf = C6F13, C7F15) are yellow liquids whereas (C8F17)2PI is a yellow solid. Oxidation of (Rf)2PI with excess NO2 led to (Rf)2P(O)OH (Rf = C6F13, C7F15, C8F17) in > 90% isolated yields after aqueous hydrolysis of the anhydride intermediates. These highly fluorinated phosphinic acids are white solids with sharp melting points and are highly soluble in methyl sulfoxide (DMSO) and 1,1,2-trichlorotrifluoroethane. However, solubility in chloroform and methylene dichloride is low. These perfluoroalkylphosphinic acids were characterized by IR, NMR (1H, 19F, and 31P), and mass spectra and elemental analysis.  相似文献   

15.
Different from C60 dianion which readily reacts with electrophiles, supramolecular C60 dianion (2) generated from gamma-cyclodextrin-bicapped C60 (1) and NaBH4 (or diborate) in DMSO-H2O (9:1, v/v) is able to reduce N-N+, C=C-EWG and C=O bonds to provide the respective dihydro derivatives; 1-mediated reduction of acetophenone with NaBH4 in the presence of (Me2N)2CH2 and EtONa gives turn over frequency (TOF)/h of 400.  相似文献   

16.
17.
A semiempirical (AM1) calculation on the structures and stabilities of isomers of the fullerene derivatives C60O and C70O is carried out. The ozonolysis reaction mechanism and the thermodynamics of the compounds are studied. The two isomers of C60O (56 bond and 66 bond) formed by an oxygen atom bridging across a C-C bond have an epoxide-like or an annulene-like structure. According to the ozonolysis reaction mechanism and kinetic factor analysis, the possible products of this ozonolysis reaction are C60O with oxygen bridging over the 66 bond (C2v) as an epoxide-like isomer and that with oxygen bridging over the 56 bond (Cs) as an annulene-like isomer. Further, the sixteen isomers of C70O (both epoxide-like and annulene-like structures) have been studied with respect to the same reaction mechanism. The most possible product in this ozonolysis reaction contains oxygen bridging across in the upper part (66 bond in C70O-2 or C70O-4) as an epoxide-like structure. The other possible product is C70O-8 (annulene-like structure), in which oxygen bridges across an broken equatorial CC bond in C70 (D5h). The vibrational frequency analysis and the electronic structure of the selected C60O and C70O isomers are generated for experimental characterisation. The experimental results indicate that C60O and C70O may decompose into the odd number fullerenes C59 and C69. We therefore studied the structures of C59 and C69 also.  相似文献   

18.
19.
The material formed by depositing C(2)(-) anions onto/into thin C(60) films (on graphite) at room temperature has been studied by means of thermal desorption mass spectroscopy, ultraviolet photoionization spectroscopy, atomic force microscopy (AFM), and surface enhanced Raman spectroscopy. As-prepared, C(2)/C(60) films manifest thermal desorption behaviour which differs significantly from pure C(60) films. Whereas the latter can be fully sublimed, we observe decomposition of C(2)/C(60) films to a high-temperature-stable material while predominantly C(60), C(62), and C(64) are desorbed in parallel. Deposition of C(2)(-) also leads to significantly modified electronic and vibrational properties. Based on DFT model calculations of the Raman spectra, we suggest that as-prepared C(2)/C(60) films contain appreciable amounts of polymeric networks comprising -C(2)-C(60)-C(2)-C(60)- chains. Detection of sublimed C(62) and C(64) upon heating implies that thermal decomposition of C(2)/C(60) films involves addition/uptake of C(2) units into individual fullerene cages. Correspondingly, annealing films up to various intermediate temperatures results in significant modifications to valence-band UP spectra as well as to surface topographies as imaged by AFM. The novel carbonaceous material obtained by heating to T > 950 K has a finite density of states at the Fermi level in contrast to as-prepared C(2)/C(60). It comprises fused fullerene cages.  相似文献   

20.
Aryliminopropadienethiones 9 have been generated by flash vacuum thermolysis of isoxazolones of the type 5 and characterized by mass spectrometry and matrix isolation IR spectroscopy in conjunction with DFT calculations and chemical trapping.  相似文献   

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