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1.
分子拓扑指数在晶格能中的应用凌天才(重庆师范学院化学系重庆630047)关键词拓扑指数,晶格能分子拓扑指数实际上是分子图的不变量。自wiener ̄[1]于1947年首次提出wiener指数并用以关联烃类的沸点等数据以来,分子拓扑指数广泛用于关联与预测...  相似文献   

2.
顺反异构键参数拓扑指数及其在相关顺反异构分子性质中的应用张宏光,辛厚文(中国科技大学近代化学系,合肥230026)关键词:顺反异构分子,键参数拓扑指数分子的拓扑指数是近几十年来发展起来的一种重要的分子图不变量。自1947年Winner提出第一个分子拓...  相似文献   

3.
氢化物的酸性与分子拓扑指数的关系   总被引:47,自引:2,他引:47  
氢化物的酸性与分子拓扑指数的关系余训民杭义萍(湖北荆州师专化学系荆州市434100)毛明现(广西梧州师专化学系贺县542800)分子的拓扑性质是分子在内外因素连续变化过程中始终保持不变的几何性质,它是分子的固有的性质之一。自1947年Wiener提出...  相似文献   

4.
烷烃物理化学性质的四参数方程   总被引:2,自引:0,他引:2  
烷烃物理化学性质的四参数方程张向东,詹庆云,赵立群(辽宁大学化学系,沈阳110036)(丽水师专,323000)(沈阳化工学院,110021)在物性与结构的定量关系(QSPR)的研究中,受到普遍关注的是拓扑指数法,这是由于拓扑指数由分子拓扑图得到不依...  相似文献   

5.
分子轨道图形理论的应用(Ⅲ)──估算E_π的断键法赵洪刚,杨开海,王长生,张继才,曹阳(辽宁师范大学化学系,大连,116022)(苏州大学化学系,苏州)关键词π电子总能量,矩,分子拓扑在分子轨道图形理论中,对一般的应用,π电子总能量Eπ的近似表达式就?..  相似文献   

6.
无机化学实验(Ⅱ)结合科研选题的尝试陈慧兰,吴琴媛,徐培珍(南京大学化学系210008)1989年以来,南京大学化学系为化学专业三年级学生开设了无机化学实验(Ⅱ)必修课(学时72)。学生通过选做几个综合性的研究课题,综合应用四大基础化学实验的原理和操...  相似文献   

7.
烯烃的热力学性质与价键拓扑指数的关系研究   总被引:8,自引:0,他引:8  
烯烃的热力学性质与价键拓扑指数的关系研究倪才华冯志云*(荆州师专化学系434100)在有机化合物结构与性能研究中,用拓扑指数研究饱和烷烃的物理化学性质已有了较多尝试。因为饱和烷烃分子中键的类型只有C-Cσ单键和C-Hσ单键,在省氢分子图上,任意一根化...  相似文献   

8.
脂肪酯结构与摩尔体积关系的拓扑化学研究王克强(洛阳师范高等专科学校化学系,471022)分子结构与性能关系的研究,是化学中一个十分活跃的研究领域。近年来,拓扑学的发展及其向化学领域的渗透为结构性能关系的深入研究提供了一种有力的研究工具,引起了国内外学...  相似文献   

9.
新型无机离子交换剂的研究Ⅴ.偏磷酸铈的离子交换色谱法应用苏政权(广东药学院预防医学系卫生化学教研室广州510224)封惠侠(河南信阳教育学院化学系河南464000)张秀莲(广东教育学院化学系广州510303关键词离子色谱偏磷酸铈分离中图分类号O657...  相似文献   

10.
线叶紫菀中一个单萜酸的化学结构王明安,陈耀祖(北京农业大学应用化学系,北京,100094)(兰州大学化学系)关键词线叶紫菀,单萜,结构分析线叶紫菀(AsterfarreriW.W.SmithetJ.F.Jeffery)系菊科紫菀属多年生草本植物,用于...  相似文献   

11.
The reactions of N-substituted hydroxylamines with alkenals serve as a method for the synthesis of the corresponding 2-substituted 3(5)-hydroxyisoxazolidines. The reaction pathway is determined by the nature of the substituent attached to the nitrogen atom. Ring-chain isomerism has been detected in these newly obtained compoundsTranslated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1270–1276, September, 1987.  相似文献   

12.
Triazenide [M(eta2-1,3-ArNNNAr)P4]BPh4 [M = Ru, Os; Ar = Ph, p-tolyl; P = P(OMe)3, P(OEt)3, PPh(OEt)2] complexes were prepared by allowing triflate [M(kappa2-OTf)P4]OTf species to react first with 1,3-ArN=NN(H)Ar triazene and then with an excess of triethylamine. Alternatively, ruthenium triazenide [Ru(eta2-1,3-ArNNNAr)P4]BPh4 derivatives were obtained by reacting hydride [RuH(eta2-H2)P4]+ and RuH(kappa1-OTf)P4 compounds with 1,3-diaryltriazene. The complexes were characterized by spectroscopy and X-ray crystallography of the [Ru(eta2-1,3-PhNNNPh){P(OEt)3}4]BPh4 derivative. Hydride triazene [OsH(eta1-1,3-ArN=NN(H)Ar)P4]BPh4 [P = P(OEt)3, PPh(OEt)2; Ar = Ph, p-tolyl] and [RuH{eta1-1,3-p-tolyl-N=NN(H)-p-tolyl}{PPh(OEt)2}4]BPh4 derivatives were prepared by allowing kappa1-triflate MH(kappa1-OTf)P4 to react with 1,3-diaryltriazene. The [Os(kappa1-OTf){eta1-1,3-PhN=NN(H)Ph}{P(OEt)3}4]BPh4 intermediate was also obtained. Variable-temperature NMR studies were carried out using 15N-labeled triazene complexes prepared from the 1,3-Ph15N=N15N(H)Ph ligand. Osmium dihydrogen [OsH(eta2-H2)P4]BPh4 complexes [P = P(OEt)3, PPh(OEt)2] react with 1,3-ArN=NN(H)Ar triazene to give the hydride-diazene [OsH(ArN=NH)P4]BPh4 derivatives. The X-ray crystal structure determination of the [OsH(PhN=NH){PPh(OEt)2}4]BPh4 complex is reported. A reaction path to explain the formation of the diazene complexes is also reported.  相似文献   

13.
14.
Conclusions The mass and NMR spectra of haplophyllidine, perforine, and their derivatives have been studied. The influence of the open and cyclic forms of the molecular ion on the nature of the fragmentation has been discussed. The main routes of fragmentation of the compounds considered are due to the presence of substituents at C8 and C4.Khimiya Prirodnykh Soedinenii, Vol. 5, No. 4, pp. 273–279, 1969  相似文献   

15.
The values of activation parameters in uncured and cured epoxy resins, rubbers, and blends thereof are investigated. The dependences of activation energy and adhesion strength of epoxy-rubber compositions on rubber content are determined. The correlation of adhesion and activation energy values for polyurethane rubber and epoxy-rubber compositions is shown.  相似文献   

16.
Aroyl- and acetylhydrazones of acet- (I) and benzaldehydes (IV) and benzoylhydrazones of acet- (II) and benzaldehydes (III) were studied by x-ray structural and quantum-chemical methods in order to establish their structures. Compund (I) was the EEZ structure in the crystal. Calculations and spectral data showed that the EEE form occurs in nonpolar solvents and in the gas phase. According to crystallographic data molecules (I)–(IV) are the E-isomers (relative to the N-N bond) and the hydrazone fragments are planar. Intermolecular N-H...O H-bonds from in the crystals. The data obtained suggest that the majority of acylhydrazones are conformationally rigid on dissolution although exceptions do occur. Apparently the reasons for the difference of acetyl- and benzoylhydrazones in electrocarboxylation reactions are electronic and not steric factors.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 75–81, January, 1991.  相似文献   

17.
Reaction of the proligand Ph2PN(SiMe3)2 (L1) with WCl6 gives the oligomeric phosphazene complex [WCl4(NPPh2)]n, 1 and subsequent reaction with PMe2Ph or NBu4Cl gives [WCl4(NPPh2)(PMe2Ph)] (2) or [WCl5(NPPh2)][NBu4] (3), respectively. DF calculations on [WCl5(NPPh2)][NBu4] show a W=N double bond (1.756 A) and a P-N bond distance of 1.701 A, which combined with the geometry about the P atom suggests, there is no P-N multiple bonding. Reaction of L1 with [ReOX3(PPh3)2] in MeCN (X = Cl or Br) gives [ReX2(NC(CH3)P(O)Ph2)(MeCN)(PPh3)](X = Cl, 4, X = Br, 5) which contains the new phosphorylketimido ligand. It is bound to the rhenium centre with a virtually linear Re-N-C arrangement (Re-N-C angle = 176.6 degrees, when X = Cl) and there is multiple bonding between Re and N (Re-N = 1.809(7) A when X = Cl). The proligand Ph2PNHNMe2(L2H) reacts with [(C5H5)TiCl3] to give [(C5H5)TiCl2(Me2NNPPh2)] (6). An X-ray crystal structure of the complex shows the ligand (L2) is bound by both nitrogen atoms. Reaction of the proligands Ph2PNHNR2[R2 = Me2 (L2H), -(CH2CH2)2NCH3 (L3H), (CH2CH2)2CH2 (L4H)] with [{RuCl(mu-Cl)(eta6-p-MeC6H4iPr)}2] gave [RuCl2(eta6-p-MeC6H4iPr)L] {L = L2H (7), L3H (8), L4H (9)}. The X-ray crystal structures of 7-9 confirmed that the phosphinohydrazine ligand is neutral and bound via the phosphorus only. Reaction of complexes 7-9 with AgBF4 resulted in chloride ion abstraction and the formation of the cationic species [RuCl(6-p-MeC6H4iPr)(L)]+ BF4- {(L = L2H (10), L3H (11), L4H (12)}. Finally, reaction of complex 6 with [{RuCl(mu-Cl)(eta6-p-MeC6H4iPr)}2] gave the binuclear species [(eta6-p-MeC6H4iPr)Cl2Ru(mu2,eta3-Ph2PNNMe2)TiCl2(C5H5)], 13.  相似文献   

18.
朱劲波  马立群  梁飞  苗迎春  王立民 《应用化学》2015,32(11):1221-1230
Ti-V基储氢合金在室温、常压下即可表现出良好的储氢特性,且质量储氢容量明显高于传统AB5型储氢合金,从而在氢气的精制和回收、运输和储存及热泵等方面有较早的应用。 此外,在混合气体分离、核反应堆中处理氢的同位素、镍氢电池及燃料电池负极材料等方面也得到了广泛的研究与关注。 基于目前Ti-V基储氢合金的研究现状,概述了该类合金的优势、限制性因素(包括成因)及改性手段。 此外,为了进一步理解Ti-V基合金储氢机理、构建合金组分与储氢特性之间的对应关系,本工作重点围绕Ti-V基储氢合金及其氢化物的结构、组分优化设计展开综述,并对其未来研究方向做出展望。  相似文献   

19.
Chlorine dioxide oxidation of cysteine (CSH) is investigated under pseudo-first-order conditions (with excess CSH) in buffered aqueous solutions, p[H+] 2.7-9.5 at 25.0 degrees C. The rates of chlorine dioxide decay are first order in both ClO2 and CSH concentrations and increase rapidly as the pH increases. The proposed mechanism is an electron transfer from CS- to ClO2 (1.03 x 10(8) M(-1) s(-1)) with a subsequent rapid reaction of the CS* radical and a second ClO2 to form a cysteinyl-ClO2 adduct (CSOClO). This highly reactive adduct decays via two pathways. In acidic solutions, it hydrolyzes to give CSO(2)H (sulfinic acid) and HOCl, which in turn rapidly react to form CSO3H (cysteic acid) and Cl-. As the pH increases, the (CSOClO) adduct reacts with CS- by a second pathway to form cystine (CSSC) and chlorite ion (ClO2-). The reaction stoichiometry changes from 6 ClO2:5 CSH at low pH to 2 ClO2:10 CSH at high pH. The ClO2 oxidation of glutathione anion (GS-) is also rapid with a second-order rate constant of 1.40 x 10(8) M(-1) s(-1). The reaction of ClO2 with CSSC is 7 orders of magnitude slower than the corresponding reaction with cysteinyl anion (CS-) at pH 6.7. Chlorite ion reacts with CSH; however, at p[H+] 6.7, the observed rate of this reaction is slower than the ClO2/CSH reaction by 6 orders of magnitude. Chlorite ion oxidizes CSH while being reduced to HOCl, which in turn reacts rapidly with CSH to form Cl-. The reaction products are CSSC and CSO3H with a pH-dependent distribution similar to the ClO2/CSH system.  相似文献   

20.
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