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首次系列报道了9-H咔唑及其系列N-取代衍生物的气相HeI紫外光电子能谱,借助于Gauss-94采用RHF/3-21G基组对它们的几何构型进行优化,并用RHF/6-31G基组计算分子轨道及能级,计算的分子轨道特征和能量很好地反映了各谱带的特点和分子间电离能的变化规律。依计算结果,以及同系列分子间谱带及相应电离能的相互比较,对每个分子的UPS谱带给予指认,讨论了N-烷基化对π分子轨道的选择性去稳定化作用,并讨论了分子之间电离能的变化规律,得到一系列有益的结论。 相似文献
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首次系列报道了9-H咔唑及其系列N-取代衍生物的气相HeI紫外光电子能谱,借助于Gauss-94采用RHF/3-21G基组对它们的几何构型进行优化,并用RHF/6-31G基组计算分子轨道及能级,计算的分子轨道特征和能量很好地反映了各谱带的特点和分子间电离能的变化规律。依计算结果,以及同系列分子间谱带及相应电离能的相互比较,对每个分子的UPS谱带给予指认,讨论了N-烷基化对π分子轨道的选择性去稳定化作用,并讨论了分子之间电离能的变化规律,得到一系列有益的结论。 相似文献
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首次报道了N-(2-澳乙基)咔唑和N-乙烯基咏唑的气相Hel紫外光电子能谱(UPS),借助于Gaussian 94采用RHF/6-3lG基组优化几何构型,并用RHF/6-31G基组计算分子轨道及能级.在对咔唑和N-烷基咔唑系列分子UPS电离能变化规律研究的基础上,对这2个分子的UPS谱带给予指认,并讨论其电子结构.结果表明N-(2-溴乙基)咔唑的UPS谱与N-烷基咔唑的不同之处是在10.295,10.540Ve处出现2个Br原子的孤对轨道;N-乙烯基咔唑的UPS谱带与咔唑的相比,电离能变化的特殊性说明乙烯基与咔唑环共平面. 相似文献
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苯氰基衍生物气相HeI紫外光电子能谱研究 总被引:2,自引:0,他引:2
气相Hel(21.22eV)紫外光电子能谱(UPS)能从孤立分子的分子轨道特性上,给出研究分子的轨道能量、电子结构以及成键特性的大量信息.UPS谱的特性揭示了被电离分子轨道的成键性质,而量子化学计算能正确地指认UPS谱带的归属,从而化合物的UPS研究从分子轨道的属性上提供了研究体系的实验和理论基础.苯基腈(C6H5CN)的UPS已有过研究[1-3],但作为系列分子的间-二氰基苯(1)、对-二氰基苯(2)、1;2,4,5-四氰基苯(3)的HeI光电子能谱未见报道.这一系列分子的特点是-CN取代的数目和位置不同,通过这些分子UPS的研究找… 相似文献
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气体分子的HeI紫外光电子能谱(UPS)可提供分子不同能级的振动结构、能量以及成健类型上的大量信息.其中在探讨稳态分子的UPS研究中,人们对氧分子的研究已十分详尽门,但尚未计及同位素氧-18分子的UPS报导.涉及同位素分子的UPS研究,迄今为止仅有氛分子及其少数由氛原子组成的个别小分子,如DH,D2O和ND3等[2-4].鉴于同位素氧-18在高能物理、生物、医学以及化学等领域的重要作用,近期我国科学工作者已成功地制得高纯度的氧-18分子.研究它的性质及其与电子结构间的关系是十分紧迫的课题.为儿我们在开展与氧一18分子有关的UP… 相似文献
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报导了硫酸系列化合物DMS(二甲基硫酸),DpCPS(二对氯苯硫酸),DpTS(二对甲基苯硫醚)气相HcI紫外光电子能谱(UPs),其中DpCPS,DpTS的UPS谱为首次获得.对各体系利用MNDO方法进行了分子构型优化,对优化得到的优势构型实施RHF/6-31G量子化学计算,并利用计算结果对各个分子体系的UPS谱进行了指认,计算结果分析显示:a)S原子的孤对电厂在DpCPS和DpTS中起到阻碍形成遍及整个分子体系π轨道的阻断作用,故此不存在遍及整个分子体系的π轨道;b)通过对三体系第一电高能的对比分析表明,第一电高能所激发出的电子主要是受S原子的束缚;c)还得到另一个有意义的结论──各分子体系的第一电离能大小与HOMO中3Pz轨道所占成份成有很好的线性关系.表明体系的第一电离出的电子主要是受S原子的3Pz轨道束缚 相似文献
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系列二羰基化合物的HeI紫外光电子能谱(UPS)及量子化学研究 总被引:1,自引:0,他引:1
报道了醌及苯并酸酐等系列二羰基化合物的气相HeI紫外光电子能谱。对各体系利用Gaussian94程序RHF/3-21G进行了构型优化,对得到的优势构型采用STO-6G基组进行了轨道计算。并结合计算结果对各分子体系的UPS谱进行了分析指认。计算结果分析显示:标题化合物的第一个电离峰均是由苯环部分的共轭π键电子电离及羰基的孤对电子电离引起的,且化合物的IP~1值随羰基在HOMO轨道中权重的增大而增大。各化合物的第二、三谱带都与羰基不同类型的孤对电子峰相关联。说明羰基为此类化合物的特征基团。且分子的对称性越高,羰基的孤对电子峰n^-和n^+的平均值越大,分裂值也越大。 相似文献
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GONG Zhi-Juna② LI Qian-Shub a 《结构化学》2006,25(8):927-936
1 INTRODUCTION Since the discovery of one-dimensional metallic behavior of tetrathiafulvalene (TTF) with tetracyano- quinodimethane (TCNQ)[1], organic charge-transfer (CT) complexes and CT salts have been intensively studied in search of electrically conducting and superconducting properties[2 ~ 6] which are most unusual for an organic material. The most intriguing property is that it is excellent metal with conducti- vity similar to that of metals at room temperature[7, 8]. In these… 相似文献
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Theoretical Studies on Electronic Structures and Spectroscopy of Fluorescent Arylamino Fumaronitrile
A new series of fluorescent arylamino fumarinitrile derivatives was designed and optimized using density function theory at the B3LYP/6-31G* level. Based on the optimized geometries, the electronic, fluorescent and 13C NMR spectra are calculated with INDO/CIS, CIS-ZINDO TD, and B3LYP/6-31G* methods, respectively. Starting with the first of the series, the LUMO-HOMO energy gaps of the derivatives become wider and the fluorescent wavelengths and the main peaks in the electronic spectra are blue-shifted owing to the large steric effect of naphthyl rings. On the contrary, the energy gaps of the derivatives turn narrow, and the fluorescent wavelengths and the main peaks in the electronic spectra are red-shifted since hydroxyl groups improve the symmetry and extend the conjugation system. The chemical shifts of sp2-C on the phenyl rings are moved upfield, while chemical shifts of carbon atoms on the cyano groups and those connected with the cyano groups are changed downfield in the presence of hydroxyl groups. 相似文献
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OU Ming-Rui LI Jun-Qian 《结构化学》2008,27(1):105-111
The quantitative structure-activity relationship (QSAR) of 14 phenoxybenzoic acid derivatives was studied by ab initio method at the HF/6-31G level using Guassian03 software. The optimized structures together with some characteristic and electric parameters of the title compounds were obtained; some stereo-parameters were calculated by HyperChem software. Stepwise multiple regression and principal component regression methods are adopted to establish multi-parametric models between biological activity and parameters. The results indicated that the lager Ehomo, M, V and LogP, the smaller Etumo and S, and the higher biological activity. A theoretical direction was provided to synthesize some compounds with high activity. 相似文献
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The semi-empirical AM1 and INDO/CIS methods as well as density function theory were used to study equilibrium geometries and spectroscopic properties of the possible isomers of C78O5 based on C2v-C78. The most stable geometry of C78O5 is 28,29,30,31,52,53,70,71,73,78-C78O5(A) with one annulene-like structure and four epoxide structures. Compared with that of C2v-C78, the blue-shift in the electronic absorption spectra of C78O5 isomers is predicted. The reason for the blue-shift effect is discussed and the electronic transitions are assigned. The IR and NMR spectra of C78O5 are explored with the AM1 and B3LYP/6-31G methods based on the B3LYP/6-31G optimized geometries. 相似文献
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Nonempirical quantum-chemical calculations of 2-, 3-, and 4-chloro-substituted tetrahydropyrans by the RHF/6-31G(d) and MP2/6-31G(d) methods showed that their conformational energy increases in the transition from the 4- to the 3-chloro-substituted compound, while in the transition to the 2-substituted compound the sign changes. In each of these isomers the axial C-Cl and C-H bonds, situated in the geminal position in relation to the oxygen atom, are longer, while the electron density at their Cl and H atoms is higher than in the corresponding equatorial bonds.__________Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 196–201, February, 2005. 相似文献