Mass Spectra of Substituted Butenolides

The mass spectra of a series of substituted butenolides were studied. Their fragmentations in the mass spectrometer strongly depend upon the nature of the substitutents. The fragment's ions include the lactone skeletons, substituents, and resultant derived from the loss of a carbon dioxide from lactone.     

噻二唑基取代硫脲化合物的低分辨质谱研究

研究了两类１９种取代硫脲类化合物的低分辨ＥＩ质谱。其主要裂解方式为噻二唑环开裂，硫代羰基裂解及中性丢失。杂原子的存在对质谱裂解有重要影响     

四种新型火药的场解吸和解吸电子轰击质谱研究

本文采用FDMS和DElMS对4种新型火药进行了质谱分析,均得到了很强的分子离子峰和特征碎片峰,并对样品A进行了DEIMS的亚稳分析,得出了该类化合物的裂解规律为:M-n(NO),M-n(O),M-n(NO_2),M-n(HNO_2),M-n(OH)等。     

Peculiarities of Mass Spectra of Substituted Pyrroloquinolines

Moscow University Chemistry Bulletin - The results of the mass spectrometric studies of a series of substituted isomeric pyrrolo[2,3-g], [3,2-f], [3,2-g], and [2,3-f]quinolines are presented and...     

Mass Spectra of Substituted N-Alkylpyrroles and Related Compounds

Under El conditions, substituents on N-alkylpyrroles affect fragmentation of the alkyl groups. The electron-withdrawing character of the cyano group retarded formation of a N-methylene cation, and a labile substituent, i.e., -CHO, -CH₂COOMe, competed with an N-alkyl group to be a initial fragmentation center, MNDO calculation of the heat of formation of possible fragment ions showed that protonated pyridine is the most stable among the isobaric ions.     

多硝基多甲基取代苯的核磁共振氢谱及质谱研究

报道了4个多硝基取代苯的核磁共振氢谱及电子轰击质谱,结果表明,苯环上的氢由于受硝基的强吸电子诱导效应的影响,其质子化学位移出现于低场,同时苯环的甲基取代基也因受到负电性的影响,其化学位移值变大.在TPX、DPX、TMX、TNTM 的EIMS中,消去OH基的'邻位效应'和CNO2键的裂分及出现相同的最终裂解碎片是此类化合物的质谱特征.     

大位阻取代环戊二烯基钛,锆化合物的合成及光谱性质

通过１－环己烯基锂与６，６－二烷基富烯发生环外双键的加成反应形成大位阻取代茂锂盐；后者再与ＭＣｌ４（Ｍ＝Ｔｉ，Ｚｒ）反应，合成了７个含或不含手性碳的大位阻取代茂金属有机化合物，并研究了它们的１ＨＮＭＲ、ＥＩＭＳ和ＩＲ．     

羟甲基取代香豆素化合物的质谱

羟甲基取代香豆素化合物是亮菌甲素的同类物,由于亮菌甲素治疗胆道感染有较好的效果,而引起医学和化学界的重视,对从天然产物中提取和分离亮菌甲素及香豆素衍生物的合成进行了很多研究工作,关于香豆素及其衍生物的质谱亦有报道。     

Microwave-Assisted Rapid Preparation of Substituted Carbazole-9-acetic and Propionic Acids and their Absorption and Fluorescence Spectra

Summary.  A rapid one-pot synthesis of substituted carbazole-9-acetic and -propionic acids under microwave irradiation is described. N-Alkylation and hydrolysis was carried out in DMF without catalyst. The absorption and fluorescence spectroscopic characteristics of the title compounds are discussed. Received January 31, 2000. Accepted (revised) March 7, 2000     

Electronic Structures and Spectra of the Bases and Base Pairs of Nucleic Acids

The present paper covers electronic structures and spectra of the bases and the base pairs of nucleic acids calculated by using the INDO/S method. For free bases we give the energy levels of ground states and transition energies of low-lying excited states and discuss the band characters. The results indicate that the calculated spectra are in good agreement with experimental values. On the other hand, our calculations for A-T and G-C pairs are very beneficial to understanding hydrogen bond properties of these pairs.     

轴向为烷氧基配位的萘酞菁硅配合物的光谱及光稳定性

轴向为烷氧基配位的萘酞菁硅配合物的光谱及光稳定性;萘酞菁硅;轴向烷氧基配位;光谱性质;光稳定性     

巴比妥酸苯胺取代衍生物二阶非线性光学性质和电子光谱的INDO/CI研究

利用量子化学密度泛函理论（DFT）B3LYP方法，在6-31G~*基组下对巴比妥酸 苯胺取代衍生物体系BA1～BA5进行几何结构优化，以优化后的构型为基础，应用 INDO/CI方法进行电子光谱计算，并结合实验数据进行了分析，同时应用完全态求 和（SOS）公式计算二阶非线性光学（NLO）系数β_μ,设计的系列体系中β_μ最 大值可达到65.47×10~(-30)esu。进一步探讨了体系的共轭性和烷基取代基链的长 度对二者的影响，结果表明，体系的共轭程度越高，烷基取代基的链长度赵长，体 系β_μ值越大，而λ_max红移。     

Novel Method for Selective Debenzylation Under Maintenance of Fluoro Atom Substituted on β-Amino Acids

tert-Butyl (R)-3-amino-3-(3-fluorophenyl)propanoate(5) was prepared with conventional debenzylation method. However, the tert-butyl (R)-3-[(S)-1-phenylethyl-amino]-3-(3-fluorophenyl) propanoate(6) and tert-butyl (R)-3-amino-3-phenylpropanoate(7) were generated as the byproducts under the general catalytic hydrogenation Pd(OH)2/C-H2 conditions. So a series of experiments was performed to optimize the reaction conditions so that product 5 could be obtained with high purity and yield. Finally an effective cata...     

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…     

溶剂中微量水对取代酞菁锌吸收光谱的影响

测定了6种烷氧基取代酞菁锌在不同溶剂中的电子吸收光谱. 在一些溶剂(如甲苯、氯仿和二氯甲烷)中, 除了存在典型的Q带吸收峰外, 在其长波长一侧还可观测到一个新的吸收峰, 结合对其荧光、核磁共振谱、添加强碱性溶剂(吡啶)以及对溶剂除水后的光谱的研究, 证实了新产生的吸收峰与溶剂中的微量水有关, 探讨了该吸收峰产生的原因.     

用高分辨质谱研究二茂铁类化合物

研究了八种N－二茂铁甲基苯胺衍生物的电子电离质谱（EI－MS），并与快原子轰击质谱（FAB－MS）作了比较，讨论了这些化合物的质谱特征。通过精确质量测量，确认了M^ -2 OH离子，并采用碰撞诱导裂解（CID）探讨了化合物质谱中主要离子间的关系。