玻碳电极表面氧化物的现场红外反射光谱电化学研究

碳材料是广泛使用的电极材料之一,其表面氧化物的存在与性质对电极性能有很大的影响;有人曾对此进行过不少的研究,但对现场振动光谱电化学的研究报道尚少,文献上只见到有关拉曼光谱的实验结果。本文报道利用现场红外反射光谱电化学方法研究玻碳电极表面氧化物所得到的一些结果。实验方法及条件     

金属碳笼

概要地综述了碳笼物理化学的新进展：金属碳笼（Ｍｅｔａｌｌｏ－Ｃａｒｂｏｈｅｄｒｅｎｅｓ），包括金属碳笼在实验上的发现、结构和稳定性、生长机理、化学反应性质等。     

C60CH2结构和电子光谱的理论研究

用ＩＮＤＯ系列方法研究Ｃ６０ＣＨ２的两种结构，ＣＨ２加在两个六元环之间的键上为Ｃ２０构型，ＣＨ２加在一个五元环和一个六元环之间的键上为Ｃ５构型，计算表明，从总能量和ＬＵＭＯ－ＨＯＭＯ能级差看，Ｃ６０ＣＨ２的稳定结构应是Ｃ２０构型，该Ｃ２０异构体有类环丙结构（Ｃ１５－Ｃ３０桥键键长为０．１５５６ｎｍ，键序等于０．８６６３），其电子光谱计算结果与实验值符合较好。     

红外法测定稀土金属及氧化物中碳硫

介绍高频红外法测定稀土金属和氧化物中碳硫量的一种快速，灵敏方法，并对试样制备，处理和保存条件作了探讨，对助熔剂，分析时间及称样量作了较详细的研究，获得最佳条件，测定结果的ＲＳＤ碳〈１．３％，硫〈１．８％。     

C59O的结构,电子光谱及NMR谱的理论预测

用ＩＮＤＯ系列方法对Ｃ６０的取代产物Ｃ５９Ｏ进行几何构型优化，得到Ｃｓ对称性的稳定构型，以此构型为基础，计算并预测了Ｃ５９Ｏ的电子光谱和ＮＭＲ谱。最后与Ｃ５９Ｏ的等电子分子体Ｃ＾２－６０及Ｃ６０Ｏ进行了比较。     

碳笼烯C32和碳笼烷C32H32的量子化学研究

用量子化学计算方法ＭＮＤＯ和ＡＭ１研究了具有Ｏｈ对称性的碳笼烯Ｃ３２和碳笼烷Ｃ３２Ｈ３２的几何结构和电子结构及其稳定性，ＡＭ１水平下，评论Ｃ３２的基态性质和分子振动。     

含羞草中新黄酮碳苷的结构鉴定

研究了海南含羞草(Mimosa pudica)的化学成分,利用Diaion HP-20、Toyopearl HW-40、MCI-Gel CHP-20、Sephadex LH-20、RP18及硅胶等柱色谱法对海南含羞草成分进行分离纯化。根据理化性质和波谱方法(1H-NMR、13C-NMR、1H-1HCOSY、HSQC、HMBC、ESI-MS、IR等)鉴定化合物的结构。结果表明,新化合物为5,7,3′,4′-四羟基-6-C-[β-D-芹糖-(1→4)]-β-D-葡糖黄酮碳苷;另一已知化合物5,7,4′-三羟基-8-C-β-D-葡糖黄酮碳苷为首次从该植物中分离得到。     

C120O2的分子结构和光谱性质的理论研究

用INDO系列方法研究双笼氧化物C₁₂₀O₂分子可能异构体的结构,两个氧以桥键形式分别加成到两个碳笼上,在两个碳笼中间形成呋喃型五元环结构,有6/6连接和6/5连接两种C₂v构型.计算表明,C₁₂₀O₂两种构型中6/6连接的C₂v构型更稳定,其光谱与实验值相符.双笼氧化物C₁₂₀O₂的形成既缓解了C₆₀O环氧处的角张力,又比C₁₂₀O分子获得了更强的笼间相互作用,两个C₆₀靠两个呋喃型五元环连接在一起.两个碳笼的多位置直接键连使两碳笼距离较近,有较强的相互作用,但仍各自表现出一定的独立性.C₁₂₀O₂可发生分解生成新的化合物.     

依碳氯替泼诺的结构分析研究

对依碳氯替泼诺的红外光谱(IR)、紫外光谱(UV)、质谱(MS)、氢-氢相关谱(^1H-^1HCOSY)、碳谱(DEPT-45、DEPT-90、DEPT-135)、碳氢相关谱(HMQC)数据和解析进行了全面的报道。对所有的^1H NMR、^17C NMR谱的信号进行了归属，讨论了质谱的主要碎片离子的可能裂解方式和红外所对应的官能团的振动吸收形式、紫外特征吸收峰所对应的不饱和共轭体系电子跃迁能量。     

碳笼化合物的高效液相色谱研究

采用化学键合固定相（ＤＮＡＰ－ＳＰ）及二元混合流动相（５０％苯－正已烷），对碳笼化合物Ｃ６０与Ｃ７０的高效液相色谱（ＨＰＬＣ）分析及分离进行了研究。比较了多种流动相对Ｃ６０、Ｃ７０分离效果的影响，苯／正已烷混合体系是最好的流动相。     

富勒烯离子Jahn-Teller畸变和光谱研究进展

M_xC₆₀ (M= K、Cs、Rb) 具有的超导性启发人们对C₆₀^n- 和C₇₀^n- 展开了深入研究。本文综述了富勒烯离子C₆₀^n±、C₇₀^n±、C₇₆^n±、C₇₈^n±及C₈₀^n±的结构畸变和光谱研究进展,介绍了国内外近十几年来众多研究小组的有关工作,从实验检测到理论计算, 从结构探讨到谱学性质研究, 并结合作者在此方面的理论研究成果,进一步探索富勒烯离子Jahn-Teller 畸变的特点和产生原因以及其电子光谱的规律性。     

Semi-Empirical and DFT Studies on Structures and Spectra for C78（CH2）2

Eighteen possible isomers of C78（CH2）2 weTe investigated by the INDO method. It was indicated that the most stable isomer was 42,43,62,63-C78（CH2）2, where the -CH2 groups were added to the 6/6 bonds located at the same hexagon passed by the longest axis of C78 （C2v）, to form cyclopropane structures. Based on the most stable four geometries of C78（CH2）2 optimized at B3LYP/3-21G level, the first absorptions in the electronic spectra calculated with the INDO/CIS method and the IR frequencies of the C-C bonds on the carbon cage computed using the AM1 method were blue-shifted compared with those of C78 （C2v） because of the bigger LUMO-HOMO energy gap and the less conjugated carbon cage after the addition. The chemical shifts of ^13C NMR for the carbon atoms on the added bonds calculated at B3LYP/3-21G level were moved upfield thanks to the conversion from sp^2-C to sp^3-C.     

Monometallic cyanide cluster fullerene YCN@C78: A theoretical prediction

Stimulated by the recent experimental success in production and characterization of YCN@C_s(6)‐C₈₂, the possibility of encapsulating YCN cluster in the C₇₈ fullerene has been performed using density functional theory. Six isomers of YCN@C₇₈ are considered based on six lowest energy C₇₈^2? isomers. The results reveal that YCN@D_3h(24109)‐C₇₈ and YCN@C_2v(24107)‐C₇₈, both of which satisfy the isolated‐pentagon rule, present excellent thermodynamic stability with very small energy differences. Moreover, the large HOMO‐LUMO gaps (1.55 and 1.47 eV for YCN@D_3h(24109)‐C₇₈ and YCN@C_2v(24107)‐C₇₈, respectively) indicate their high kinetic stabilities. Significantly, in both the structures, the encapsulated YCN cluster is triangular, similar to the cases of YCN@C_s(6)‐C₈₂ and TbCN@C₂(5)‐C₈₂. In addition, electronic absorption spectra, infrared spectra, and ¹³C nuclear magnetic resonance spectra of two stable structures have also been explored to further disclose the molecular structures and properties. © 2015 Wiley Periodicals, Inc.     

Structures,stabilities, and IR and 13C-NMR spectra of dihedral fullerenes: A density functional theory study

Dihedral fullerenes are thermodynamically stable molecules with D nd or D nh symmetry.Based on experimental findings,two series of dihedral fullerenes with five-fold(C5) and six-fold(C6) symmetry have been studied using density functional theory(DFT).The DFT calculations showed that for both series the stabilities increased with increasing fullerene size.Structural analyses indicated that the stabilities are related to specific local geometries.In the case of the more abundant C5 series,the presence of approximately planar pentagons and hexagons on the top bowl favors their formation.That is to say,those fullerenes with small dihedral angles within the polygons are readily formed,because planar hexagons lead to strengthened conjugation which lowers average bonding energies(ABE) and increases thermodynamic stabilities.Non-planar hexagons at equatorial positions in tube-shaped fullerenes have an adverse effect on the conjugation and inhibit their formation.Calculations also demonstrated that fullerenes in the two series,including C 50(D 5h),C 60(D 6h),C 80(D 5d),C 96(D 6d),C 110(D 5h),and C 120(D 5d),have thermodynamically stable triplet structures with strong conjugation.The calculated IR and 13 C NMR spectra of the fullerenes show some similarities and regular trends due to their homogenous structures.The electronic structures indicate that short double bonds in hexagons with high electron occupancies are readily attacked by electrophilic agents and can also be coordinated by transition metals.Mechanistic discussions suggested that C 2 additions and C 2 losses constitute reversible processes at high temperature and C 2 additions in pentagonal fusions are crucial to the kinetics of the curvature of structures.C 3 additions lead to the formation of large fullerenes of other types.     

Studies on the Electronic Structures and Spectra of C78（CH2）3

The structures and spectra of 20 possible isomers of C78(CH2)3 have been studied by using AM1,INDO/CIS and DFT methods. The results show that the most stable isomer is 1,2,3,4,5,6-C78(CH2)3 (A) with annulene structures,where three -CH2 groups are added to the 6/6 bonds located at the same hexagon passed by the shortest axis of C78 (C2v). Compared with that of C78 (C2v),the first absorption in the electronic spectrum of C78(CH2)3 (A) is blue-shifted because of its wider LUMO-HOMO energy gap. While the IR frequencies of the C–C bonds on the carbon cage are red-shifted owing to the formation of annulene structures and the extension of the conjugated system. The chemical shifts of the carbon atoms in 13C NMR spectra are moved upfield upon the addition.     

Progress in fullerene fluorination

Fluorofullerenes hold the promise of being useful synthetic intermediates, because of the ease with which they undergo nucleophilic substitution. However, the progress in this field has been hampered by the difficulty in controlling fluorination for the preparation of fluorofullerenes of either low, or specific fluorine content. In this paper, previous work is described together with the latest developments involving the use of metal fluorides as fluorinating species. The availability of specific fluorofullerenes has made it possible to make the first detailed studies of the nucleophilic substitution reactions. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 852–861, May, 1998.     

C74(BN)2的UV和IR 光谱研究

Equilibrium geometries of 16 possible isomers for C74（BN）2 were studied by INDO series of methods, to indicate that the most stable three geometries are those where boron and nitrogen atoms substitute carbon atoms located at the same hexagon near the longest axis of C78 （C2v） to form B-N-B-N unit. Electronic spectra of C74（BN）2 were investigated with INDO/CIS method. The reason for the red shift of UV absorptions for C74（BN）2 compared with those of C78 （C2v） was discussed. IR spectra for 9,8,28,29-C74（BN）2 and 28,29,30,31-C74（BN）2 were calculated on the basis of AM1 geometries.     

Investigation on Electronic Structures and Spectra for the Substituted Fullerene C77B-

1 INTRODUCTION After Guo[1] synthesized and detected C60-nBn and C70-nBn by mass spectra, investigations on fullerenes doped by other atoms became more and more interesting. Andreoni[2] studied the impurity states of the doped fullerenes C59B; Dong[3] calculated the structural and electronic properties of C59B; Wang[4] assessed the stability of heterohedral fullerenes C60-xBx. Lamparth[5] prepared C59N and C69N , and put forward the possible structures for C59N . Sahoo[6] obtained…     

螺旋共轭化合物的结构光谱和二阶非线性光学性质的理论研究

用ＡＭ１和ＩＮＤＯ／ＣＩ方法研究了螺旋共轭化合物（ｎ＝１～５）的结构和电子光谱,并在此基础上,用完全态求和公式（ＳＯＳ）自编程序计算了二阶非线性光学系数,从理论上研究了１,４－环己二烯环数增加时对二阶非线性光学性质的影响