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1.
C60CH2结构和电子光谱的理论研究   总被引:1,自引:1,他引:1  
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。  相似文献   

2.
用INDO系列方法研究C60NH^+2的2种构型,一是NH^+2加在2个六元环之间的键上,为C2构型,另一个是NH^+2加在五元和六元环之间的键上,为Cs构型,计算表明,C60NH^+2的稳定构型应是C2,且该C2V异构体有质子化的环乙亚胺结构(桥C15-C30为0.1520nm键序为0.9097),同时计算了C60NH^+22种构型的电子吸收光谱,讨论了其NMR谱,属于理论预测性质。  相似文献   

3.
用INDO系列方法研究C60O2可能异构体的结构,两个氧原子分别加在两个六元环相邻边或五六元环相邻边形成环氧结构,为Cs对称性,得6种可能构型,计算表明,两个氧原子加在同个六元环的六六元环相邻边所形成环氧结构Cs构型最稳定,环氧处C-C键不断开,与实验结果一致,其电子光谱计算结果亦与实验值相吻合,这种Cs构环氧结构所在六元环上的另一个C-C键有大的键序,为高活性位置,因此C60O2可能有较好的化学  相似文献   

4.
用密度泛函方法研究了LaC3n(n=-1,0,+1)分子簇的结构和稳定性,对这个四原子体系,提出了5种可能构型,其中3种具有C2v对称性,2种为C∞v对称性.在C2v对称性结构中,其中1个为La接在弯曲的C3链上,第2个是La通过2个键与C3环相链,第3个是La通过1个键与C3环相连;在C∞v对称性中,第1个La接在C3链的一端,而在第2个构型中,La被插入在C3链中.结果表明,环状结构当La接在弯曲的C3链上的是局域极小值并且最稳定  相似文献   

5.
用密度泛含方法研究了LaC5n(n=-1,0,+1)分子簇的结构和稳定性及振动光谱,对这个六原子体系提出了三种可能构型,点群结构为C2v对称性.第一个构型为La接在弯曲的C5链上,第二个是La通过二个键与C5环相连第三个是La通过一个键与C5环相连;结果表明,第一个构型即当La接在弯曲的C5链上时能量最低.振动光谱分析指出,当n=-1时,第二个构型为局域极小值;当n=+1时,第一个和第二个构型为局域极小值;对n=0,局域极小值没有找到.  相似文献   

6.
合成了[Mn_2(bzacen)_2(MeOH)_2(μ-4,4′-bipy)](ClO_4)_2化合物,并测定其晶体结构。该晶体属单斜晶系,空间群P2_1/n,晶胞参数:a=1.3082(3)nm,b=1.2713(3)nm,c=1.8006(5)nm,β=110.91(2)°,Z=2,μ=5.97cm-1,R=0.0580,GOF=1.66.在配合物阳离子中,4,4′-联吡啶桥联2个[Mn(bzacen)(MeOH)]+,而锰原子具有3个N原子和3个O原子形成的扭曲八面体配位构型。红外光谱和拉曼光谱均表明,形成配合物后,v_(C=N)、v(C=O)、和v(C=C)移向低频。红外光谱的1110cm ̄(-1)谱带表明ClO_4 ̄-未与Mn(Ⅲ)配位,812cm ̄(-1)振动说明4,4′-bipy充当桥联二齿配体。拉曼光谱中的463cm ̄(-1)和401cm ̄(-1)别为Mn-O和Mn-N的振动带。电子光谱证明存在d-d、d-π和π-π跃迁。电极电位测定显示该配合物Mn(Ⅲ)的价态是稳定的。  相似文献   

7.
用INDO系列方法研究了由C60^2-制备的衍生物HC60CH2C6H5的结构和UV光谱。结果表明,六元环上的1,2-异构体具有Cs对称性,1,4-异构体具有C1对称性。以优化构型为基础,计算两种加成产物的UV光谱,表明1,2-异构体的特征吸收与实验值相符;同时,对1,4-异构体的UV光谱进行了理论预测,对电子跃迁进行了理论指认,并分析了光谱红移的原因。  相似文献   

8.
用SCF-MO-AM1方法计算研究了1,3,3-三硝基氮杂环丁烷和它的三个衍生物的分子几何构型,电子结构和热解机理,分子中连结偕二硝基的两个C-N键级较小,均裂该建所需活化能较低,可能是优先发生的主要热解引发反应,四个标题物均裂该键的活化能和该键的Wiberg键级之间存在良好的线性关系,线性相关系数为0.99。  相似文献   

9.
三羰基环戊二烯基钼负离子与1,3-二卤丙烷在一缩二乙二醇二甲醚介质中反应,生成环卡宾配合物CpMoX(CO2)CO(CH2)2CH2(X=Br.I)硅桥连双环戊二烯基三羰基钼负离子与1,3-二卤丙烷顺利地进行类似反应,生成相应的硅桥连双(环卡宾钼配合物)-E(C5H1MoX(CO)2CO(CH2)2CH2)2(E=Me2Si,Me2SiSiMe2,Me2SiOSiMe2),化合物硅氧硅桥联二茂二钼  相似文献   

10.
用密度泛函方法研究了LaCn及La2Cn(n=-1,0,+1)分子簇的结构和稳定性.对La2Cn体系,提出了两种可能构型,其中一种具有C2v对称性,另一种具有D∞h对称性.计算结果表明,对La2Cn,当n=+1,-1时,线状结构最稳定,并且在n=+1时,C2v结构极不稳定有收敛向线状结构的趋势.而当n=0时,C2v结构最稳定.最后还计算了LaC和La2C分子簇的电子亲和势和离化能.  相似文献   

11.
用INDO系列方法研究了C~6~0SiH~2的两种结构: 一是SiH~2加在两个六元环之间的键上形成C~2~v构型; 另一是SiH~2加在一个五元环和一个六元环之间的键上形成C~s构型。从总能量和LUMO-HOMO能级差看, C~6~0SiH~2的稳定结构应是C~2~v构型, 其中桥C(15)-C(30)的键长为0.1508nm, 键序为0.9369, 说明不开环, 形成类环丙烷结构。文中计算了两种构型的电子吸收光谱和NMR谱, 此类计算是基于对C~6~0SiH~2的等电子体C~6~0O和C~6~0CH~2的研究之上, 且后两者的研究结果与实验相一致。  相似文献   

12.
The spectral analysis indicates that all isomers of C60O, C70O and C60O2 have an epoxide-like structure (an oxygen atom bridging across a C–C bond). According to the geometrical structure analysis, there are two isomers of fullerene monoxide C60O (the 5,6 bond and the 6,6 bond), eight isomers of fullerene monoxide C70O and eight isomers of fullerene dioxide C60O2. In order to simulate the real reaction conditions at 300 K, the calculation of the different isomers of C60O, C60O2 and C70O fullerene oxides was carried out using the semiempirical molecular dynamics method with two different approaches: (a) consideration of the geometries and thermodynamic stabilities, and (b) consideration of the ozonolysis mechanism. According to the semiempirical molecular dynamic calculation analysis, the probable product of this ozonolysis reaction is C60O with oxygen bridging over the 6–6 bond (C2v). The most probable product in this reaction contains oxygen bridging across in the upper part of C70 (6–6 bond in C70O-2 or C70O-4) an epoxide-like structure. C60O2-1, C60O2-3 and C60O2-5 are the most probable products for the fullerene dioxides. All of these reaction products are consistent with the experimental results. It is confirmed that the calculation results with the semiempirical molecular dynamics method are close to the experimental work. The semiempirical molecular dynamics method can offer both the reaction temperature effect by molecular dynamics and electronic structure, dipole moment by quantum chemistry calculation.  相似文献   

13.
C60O3的结构和电子光谱的理论研究   总被引:1,自引:1,他引:0  
用INDO系列方法对C60O3的可能构型进行研究,结果表明:环氧结构邻近的6-6键易发生进一步的加成反应.其中3个氧原子加在同一个六元环的6-6边上,形成环氧结构最稳定的C3v构型,第3个氧原子加在2个环氧结构相邻的六元环的6-6边上的C2、Cs构型也相当稳定,C2、Cs构型的部分13C NMR谱与实验吻合.C60O3可能有较好的反应活性,其电子光谱属于理论预测.  相似文献   

14.
Intermediate neglect of differential overlap (INDO ) calculations were used to study two structures of C60NH: one of C, geometry with a bridging NH across the bond between two fused six-membered rings in C60 and the other of Cs geometry with a bridging NH across the bond between a five- and a six-membered ring. We calculated the most stable isomer of C60NH to be of C, symmetry. It was found that the C isomer has a protonated aziridine structure with a bridging C? C bond length of 0.1520 nm. The electronic spectra of both isomers of C60NH were calculated. Comparisons were made with the isoelectronic molecules C60O and C60CH2, cases in which the calculated electronic spectra for the most stable isomers C60O (C) and C60CH2 (C) are in good agreement with recent experimental results. © 1995 John Wiley & Sons, Inc.  相似文献   

15.
计算了气相反应C60+O3=C6O(C2v)+O2的热力学函数.得到了该反应Gibbs自由能的具体数值,结果表明在所研究的温度范围内Gibbs自由能为负值,从热力学角度来说,该反应可以自发进行,在计算该气相反应热力学函数的基础上,给出了气相C6O(C2v)的标准热力学函数  相似文献   

16.
用半经验的AM1, PM3及ab initio方法对C60NH两种异构体的结构及光谱进行了理论计算。结果表明, 具有开环结构的C60NH的5/6异构体稳定性要高于具有闭环结构的6/6异构体。计算了两种异构体开环与闭环过程的反应坐标, 发现6/6开环异构体是势能面上的一局部最小点, 而5/6闭环异构体不存在6/6异构体的H可以在两种镜面异构体之间快速翻转, 使其核磁共振谱呈现C2v对称性。通过振动分析确认了所优化的构型确实为势能面的能量最低点, 并得到了C60NH各异构体的红外光谱。  相似文献   

17.
王振  张静 《结构化学》2011,30(5):666-671
Quantum chemical calculations on some possible equilibrium geometries of C24O2 isomers derived from C24 (D6) and C24O have been performed using density functional theory (DFT) method. The geometric and electronic structures as well as the relative energies and thermal stabilities of various C24O2 isomers at the ground state have been calculated at the B3LYP/6-31G(d) level of theory. And the 1,4,2,5-C24O2 isomer was found to be the most stable geometry where two oxygen atoms were added to the longest carbon-carbon bonds in the same pentagon from a thermodynamic point of view. Based on the optimized neutral geometries, the vertical ionization potential and vertical electron affinity have been obtained. Meanwhile, the vibrational frequencies, IR spectrum, and 13C chemical shifts of various C24O2 isomers have been calculated and analyzed.  相似文献   

18.
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   

19.
用INDO系列方法研究了C60的哌嗪衍生物C60N2(C2H4)2的结构。结果表明[6,6],异构体具有C2v对称性[6,5],异构体具有Cs对称性,前者能量较低。以优化构型为基础,计算两种加成产物的UV谱,结果表明,[6,6]异构体的特征吸收与实验值相符,同时对[6,5]异构体的UV谱进行理论预测,对电子跃迁进行了理论指认,并分析了光谱红移的原因。  相似文献   

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