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。     

C78O异构体的电子结构和光谱

The semi-empirical INDO method was used to study the electronic structures and the spectra of all of the 34 possible isomers of C78O based on C78 with group C2v. This calculation can simulate positions of an additional oxygen atom in C78 and predict the spectroscopic characteristics of the isomers. The most stable geometry of C78O is the 73,78-C78O molecule with an epoxide structure. The added 73,78-bond is located between two hexagons (6-6) and is intersected by the shortest C2 axis in C78 with group C2v. Atomic orbitals of the oxygen atom play an important role in lowering HOMO energy of 73,78-C78O. Compared with C78 with group C2v, the blue-shift in the electronic absorption spectrum for 73,78-C78O was observed.The reason of the blue-shift effect was discussed, and the electronic transitions were assigned based on the theoretical calculations.     

C_(78)~n(C_(2v))的电子结构和UV谱

用INDO (Intermediateneglectdifferentialoverlap)系列方法对Cn78进行系统研究 .结果表明 ,C78(C2v)比C78(C2v′)稳定 ;Cn78(C2v)和Cn78(C2v′)未发生Jahn Teller畸变 ;Cn78随n绝对值增大 ,体系能量升高 .以优化构型为基础 ,首次计算Cn78电子光谱 ,对电子跃迁进行理论指认 ,讨论Cn78光谱特征吸收与C78相比发生红移的原因 .     

C77N+异构体的稳定性和电子光谱研究

All of the possible 21 isomers for C77N+, an isoelectronic molecule of C78, were investigated by the INDO methods based on C78(C2V). It indicates from optimization that the most stable isomer is that the nitrogen atom substitutes C(78) located at the C(78)-C(73) bond passed through by the Y shortest axis and the atoms near the Z longest axis are also easy to substitute, whereas the atoms near the X shortest axis are relatively difficult to substitute. At the same time, C78 was compressed a little and ready to perform the further reaction to form C77 NR at the location of substitution. Electronic spectra of C77N+ were calculated by INDO/SCI method and electronic transition was theoretically assigned. The red shift of absorption peaks for electronic spectra of C77N+ took place compared with that of C78(C2V) because of its narrower LUMO HOMO energy gap. There are great differences in characteristic absorptions among C77N+ isomers, which can be considered as evidence of the formation for each isomer.     

几种C70^n离子的Jahn-Teller畸变和单态的电子光谱

用INDO系列方法对C70^n(n=+2, +1, -1, -2, -3, -4)进行系统研究, 表明除C70^n三态具有D5h对称性, 其余均发生Jahn-Teller畸变, 导致明显的对称性降低(C2v), 产生30种键长和21种不等同C原子。以优化构型为基础, 计算C70^4^-单态的电子光谱, 其近红外吸收与实验值一致, 同时预测了C70^2^+单态的光谱。     

C60O结构和电子光谱的理论研究

用ＩＮＤＯ系列方法研究Ｃ６０Ｏ的两种结构：一是桥氧加在２个六元环之间的键上为Ｃ２ｖ构型；另一个是桥氧加在１个五元环和１个六元环之间的键上为Ｃｓ构型。计算表明，从总能量、ＨＯＭＯ－ＬＵＭＯ能级差和光谱性质看，Ｃ６０Ｏ的稳定构型都应是Ｃ２ｖ构型，该Ｃ２ｖ异构体具有环氧结构（桥Ｃ１５－Ｃ３０键长为０．１５１８ｎｍ，键序为０．８７４４），其电子光谱计算结果与实验值较好地符合。     

C_(76)及C_(76)~n离子的电子结构和单态的电子光谱

Kx C76 不同于 K3C6 0 的半导体行为 [1]引起了我们对 Cn- 76 的研究兴趣 .自 Ettl[2 ]分离表征 C76 以来 ,相应的实验及理论研究已经开始 [3,4 ] ,但对 C- 76 以外其它离子的电子结构和光谱的理论研究尚未见报道 .本文用 INDO系列方法对 Cn76 进行系统研究 ,考察其是否发生 Jahn-Teller畸变 ,首次计算了 Cn76 单态离子的电子光谱 ,对电子跃迁进行理论指认 ,讨论了 Cn76 光谱的特征吸收与 C76 相比发生红移的原因 .1　研究方法以球心为坐标原点 ,将 C76 椭球体水平放置 ,取最短轴为 z轴 ,按 D2 [2 ]对称性作出 C76 的初始坐标 ,用 …     

C76及Cn76离子的电子结构和单态的电子光谱

KxC76不同于K3C60的半导体行为[1]引起了我们对Cn-76的研究兴趣. 自Ettl[2]分离表征C76以来, 相应的实验及理论研究已经开始[3,4], 但对C-76以外其它离子的电子结构和光谱的理论研究尚未见报道. 本文用INDO系列方法对Cn76进行系统研究, 考察其是否发生Jahn-Teller畸变, 首次计算了Cn76单态离子的电子光谱, 对电子跃迁进行理论指认, 讨论了Cn76光谱的特征吸收与C76相比发生红移的原因.     

C70R2（R=OH,CH30的结构和电子光谱

用ＩＮＤＯ方法研究了Ｃ７０Ｒ２（Ｒ＝ＯＨ，ＣＨ３）４种异构体的结构和稳定性，表明１，９－Ｃ７０（ＯＨ）２比７，８－Ｃ７０（ＯＨ）２稳定，两者能量差为３８．５ｋＪ／ｍｏｌ，而７，８－Ｃ７０（ＣＨ３）２比１，９－Ｃ７０（ＣＨ３）２能量低２３．０ｋＪ／ｍｏｌ。以优化构型为基础，对Ｃ７０Ｒ２（Ｒ＝ＯＨ，ＣＨ３）的电子光谱进行了理论预测。     

C70O2可能异构体的结构和电子光谱的理论研究

用AM1、PM3及INDO系列方法研究了C₇₀O₂可能异构体的结构和稳定性.在C₇₀O稳定构型的基础上,考察了C₇₀O₂的45种异构体.结果表明,两个O原子加在碳球极端处同一个六元环内不等价的6/6键上形成环氧结构的构型最稳定.在优化构型的基础上,进行电子光谱计算,并与C₇₀和C₇₀O进行了比较.     

Stabilities and Electronic Spectra for C78O2 Isomers

1 INTRODUCTION Functional derivatives of fullerenes have aroused chemists’ interest and monofunctional products are accompanied by difunctional derivatives[1～3]. Diede- rich[1] prepared and detected C70O2 by the FAB mass spectrum. Kalsbeck[2] synthesized C60On (n = 1～4) by electrochemical oxidation of C60. Wood[3] investi- gated photolysis of a crude fullerene mixture and obtained C60On (n = 2～5) and C70O2. Menon[4] stu- died the optimized structures and electronic proper- ties o…     

C80n(D2,Ih)的Jahn-Teller畸变和电子光谱

Jahn-Teller distortion of C80n(D2,Ih) was studied by the INDO method. It shows that C80(D2) is more stable than C80(Ih), which is in agreement with the experiment. Jahn-Teller distortion did not take place in C80n(D2) but happened in some of ions for C80n(Ih). Total energy of C80n was affected by the increase in absolute values of electric charges. Electronic spectra of C80 were calculated for the first time. Not only spectrum data of C80 consistent with the experiment were obtained but also electronic spectra of C80n were predicted where the electronic transition was assigned theoretically. The reason for the red shift of UV bands for C80n(D2) compared with that of C80(D2) and the blue-shift of peaks for C80n(Ih) relative to C80(Ih) is that the LUMO-HOMO energy gap of C80n(D2) is less than that of C80(D2) whereas the energy gap of C80n(Ih) is bigger than that of C80(Ih).     

Theoretical Studies on Electronic Structures and Spectra for C80^n （D5d,C2v） Singlet

1INTRODUCTIONC80iscalledthemissingfullereneduetoitsinstabilityinkineticsandlowerLUMO-HOMOenergygap[1],aswellasthelowerabundanceintheexperimentandthedifficultyinsynthesis[1~5].However,thestableexistenceofcomplexLa2@-C80[2]stimulatestheresearchinterestinionsofC80.Zhang[3]performedtheoreticalstudiesonthestabi-lityandNMRspectraforC80isomers.Nakao[4]cal-culatedtheLUMO-HOMOenergygapofC80byusingabinitiomolecularorbital.Hennrich[5]syn-thesizedC80(D5)fromfullerenesootextractionbydHPLC.…     

C_（60）~＋的Jahn－Teller结构畸变

用ＩＮＤＯ系列方法对Ｃ_（６０）的阳离子自由基Ｃ_（６０）~＋进行几何构型优化，得到Ｄ_（５ｄ）对称性的构型，表明Ｃ_（６０）~＋确实发生了Ｊａｈｎ－Ｔｅｌｌｅｒ结构畸变，形成７种键和４种不等同Ｃ原子，且单键变短，双键变长，键长趋于平均化，体系的正电荷和单电子主要分布在赤道附近，从而导致了赤道附近Ｃ原子的高反应活性。     

Cn78(C2v)的电子结构和UV谱

用INDO(Intermediate neglect differential overlap)系列方法对Cn78进行系统研究.结果表明,Cn78(G2v)比Cn78(C2v')稳定;Cn78(C2v)和Cn78(C2v')未发生Jahn-Teller畸变;Cn78随n绝对值增大,体系能量升高.以优化构型为基础,首次计算Cn78电子光谱,对电子跃迁进行理论指认,讨论Cn78光谱特征吸收与C78相比发生红移的原因.     

Studies of equilibrium geometries and electronic spectra for C78O4

Equilibrium geometries and relative stabilities of 24 possible isomers for C₇₈O₄ based on C₇₈ (C_2v) were studied by intermediate neglect of differential overlap (INDO) calculations. It was indicated that the most stable geometry is 28,29,30,31,52,53,73,78‐C₇₈O₄, where three oxygen atoms are added to the same hexagon, through which the longest axis of C₇₈ (C_2v) goes, and the forth oxygen atom is added to the C(73)? C(78) bond intersected by the shortest axis of C₇₈ (C_2v), and epoxide structures are formed. Electronic spectra of C₇₈O₄ isomers were investigated based on the optimized geometries. The blue shift of the first absorption for 28,29,30,31,52,53,73,78‐C₇₈O₄ compared with that of C₇₈ (C_2v) was rationalized and nature of transition for the peaks discussed. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2006     

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…