BH_4~-,CH_4,NH_4~ ,AlH_4~-,SiH_4,PH_4~ ,GeH_4的SCF-X_a计算方法研究

本文通过球半径比的优化选择,给出了七个含氢正四面等价电子分子的SCF-X。方法非重叠近似方案的计算结果.就中性分子CH_4,SiH_4及GeH_4而言,总能量和结合能计算值有了显著改进,使SiH_4和GeH_4的成键稳定性得到了合理说明.对离子计算,同时给出了Watson球存在和不存在的计算结果,通过对比,说明自由离子是一种更不稳定的状态,而Watson球确是稳定离子的环境的合理模拟.对离子的结合能也作了讨论,并联系了有关晶体化合物的热稳定性作出了解释.与此同时,还发现优化球半径比与中央原子的电负性存在线性关系,且符合于Virial定理的要求。     

AN SCF-X_αSW STUDY OF BH_4~-, CH_4,NH_4~ , AlH_4~-, SiH_4, PH_4~ AND GeH_4

Through the optimization of sphere radii ratios, seven tetrahedral hydrides species withequal valence electrons are investigated by means of SCF-X_αSW method in muffin-tin ap-proximation scheme. In comparison with those published results, the calculated total statis-tical energies and the corresponding binding energies of neutral molecules concerned have beenmuch better improved, which offers reasonable interpretation of their bonding stabilities, no-tably for SiH_4 and GeH_4. For ionic species, attention is focused on the role of Watson sphere,thus two kinds of calculation with and withcut Watson sphere are simultaneously given for com-parison. It reveals that free ions always behave more unstably and Watson sphere seems tobe a suitable model for describing the environment of a stabilized ion. The calculated bind-ing energies of ions have been utilized to correlate the thermostability trend for a few crystalcompounds. Also, an empirical linear relationship between optimized sphere radii ratios andelee     

Crystal Structure of 3, 4-trans-4, 5-trans-2-Amino-3-cyano-1, 3-diethyloxy carbonyl- 4, 5-di (4-chlorophenyl)cyclopentene

1INTRoDUCT1oNThechemistriesofsamariumdiiodideandlow-valenttitaniumareofcurrentin--.terestinorganicSynthesis.Theyhavebeenwidelyusedinsyntheticreactions(l.2i.Thereactivityofthereagentstowardsvariousnitrogen-containingcomPOundshasal-readybeenexamined.Thereare,toourknowledge,noliteratureexamplesforthereductionofafylidenecyanoacetatederivativeswiththesereagents.Recently,wefoundthatthetitlecompoundisobtainedbycyclodimerizationreactionofpchlorObenzylidenecyanoacetatewithsamariumdiiodideorlow-va…     

A Novel Fused Phosphorus Heterocycle: 4-(1'''',2'''',3'''',4-Tetrahydro-1, 3, 2-benzodiazaphosphorin-2''''-sulfide)-3, 4b, 4a-thiazphosphaphenanthridine Derivative

Organophosphorus compounds are ubiquitous in nature and they have broad applications in the fields of agriculture and medicine1-4. There has been a considerably growing interest in heterocyclic compounds due to their pharmaceutical importance and extensive application in organic synthesis, and the application of heterocycles is suggested to enhance the biological activity and/or offer other diverse properties5-7. In the previous work8, we have reported that 11-ethoxycarbonylmethyl-6-oxo-3, 4…     

Preparation and Electrochemical Properties of 3-Pyridinyl-6-aryl-1, 2, 4-triazolo [3, 4-b][1, 3, 4]thiadiazoles

A series of 3-pyridinyl-6-aryl-1, 2, 4-triazolo[3, 4-b][1, 3, 4]thiadiazoles(PATT) were prepared, the structures were confirmed by 1R and ^1H NMR spectra. The results of cyclic voltammetry measurements imply that all these compounds have a higher electron affinity (EA) than 2-(4-biphenyl)-5-(4-tert-butyl phenyl)-1, 3. 4-oxadiazole (PBD) which implies that PATT could be acting as better electron acceptors than widely used electron transporting material PBD.     

1, 4-氧硫杂萘-4, 4-二氧化物含氟衍生物的合成

以含氟的2-(2-氯-4-硝基苯磺酰基)-1-芳基乙酮为原料, 在K2CO3/TEBA/DMF体系中, 与烷基化试剂发生烷基化-环化反应。合成六种未经文献报道的1, 4-氧硫杂萘-4, 4-二氧化物的含氟衍生物,利用元素分析、IR、1H NMR、MS对其结构进行了表征。     

An Efficient Preparation of 4, 4′-Dicarboxy-2, 2′-Bipyridine

A convenient and high yield preparation of 4, 4′-dicarboxy-2, 2′-bipyridine from the oxidation 4, 4′-dimethyl-2, 2′-bipyridine with potassium dichromate in sulfuric acid is reported.     

Synthesis and oxidative polycondensation of 4, 4−diethynylbiphenyl

Summary 4,4-Diethynylbiphenyl was synthesized. By polycondensing it an oligomer with alternating biphenyl (-4,4) and diacetylene chains was obtained.     

4S,3d,后面呢?

在教电子构型一节时,学生们往往感到难于记住轨道的填充次序,许多教科书(也有不少教师)对此也没有给出有效的解决办法。本文介绍一个简便实用的方法,将有助于对这一问题的学习和记忆。做法如下: 1.画一张7×7的方格子图。2.在对角线上算出已知的各S轨道。     

SYNTHESIS AND STRUCTURE OF ADDUCT OF 1, 9-DIHYDRO-8,9-DIPHENYL-1, 2, 4-TRIAZOLO [4, 3-d] 1, 2, 4-TRIAZINE-3, 5-DITHIONE WITH TRIETHYLAMINE

<正> C16H13N5S2· (C2H5)3N: Mr = 440. 64, monoclinic, space group C2/c with a = 18.956(7)(?), b = 12. 866(7)(?), c = 20. 830(9)(?) , β=115. 63(3)°; Z=8; V = 4580(7)(?)3; Dc = 1. 278gcm-3; F (000) = 1872, μ= 2. 423cm-1 (MoKa). Final R is 0. 069. C16H13N5S2is non-planar with two rings, a five-member and a six-member with conformations of envelope and twist boat forms respectively, and the two substituted phenyl groups are in equatorial and axial positions.     

STUDIES ON STEREOSELECTIVE SYNTHESIS OF 4R,6R,4-ACETOXY-6-PENTYLVALEROLACTONE

The title compound has been synthesized from the chiralbuilding block 2 through five steps.     

Crystal Structure of Loliolide (5, 6,7a-Tetrahydro-6-hydroxy-4, 4, 7a-trimethyl-2 (4H)-benzofuranones)

1INTRODUCTIONThetitlecompound,C,,H,,O,(mp:146～148'C),forthefirsttime,wasiso-latedfromClinopodiumpolycephalum(Vant-)byC.Y.WuetHsuancalled"DuanXueliu"inChinesethatisusedinfolkmedicineforthetreatmentofhaemorrhagiadisease[1i.Itsstructurehasalreadybeendeterminedt2ibymeansofUV,lR,NMRandchemicalsynthesis.Sinceloliolideappearedtohaveantitumoractivity"'andim-munosuppressiveactivity'#'inrecentyears,weaffirmedthestructurebyX-raydiffractionanalysis.2EXPERIMENTALApaleyellowtransparentcry…     

面包酵母对1, 4, 4α, 8α-四氢-1, 4-亚甲基萘-5, 8-二酮的催化异构化

文章描述了面包酵母将1, 4, 4α, 8α-四氢-1, 4-亚甲基萘-5, 8-二酮催化异构化为1, 4-二氢-5, 8-二羟基-1, 4-亚甲基萘, 而不是还原为相应的羟基化合物。     

Crystal Structure of 4, 5-trans-2-Amino-1, 3, 3-tricyano-4, 5-di (4-chlorophenyl)cyclopentene. Ethanol. Monohydrate

1mTRODUCT10NSincethetimeKaganhasdem0nstratedasimplepreparationofsamariumdiio-didefromsamariummetaland1,2-diiodoethanet1),SmI2hasbeenwidelyusedinsyntheticreactionst23.Thereactivityofsamariumdiiodidetowardsvariousnitrogen-containingcomP0undshasalreadybeenexamined.Thereare,toourknowledge,noliteratureexamplesforthereductionofcyanogrouptoproduceaminowiththisreagent.Inthispaper,wediscussedthecrystalstructureofthetitlecomP0undsyn-thesizedbythereactionofsamariumdii0didereagentwithp-chloroben-zyli…     

Crystal Structure of 3-methyl-1, 2, 3, 4, 4a, 4b, 9a, 15, 15a,15b-decahydro-(4,5);(4a,15)-dimethano-tricyclo(4, 3, 1, 0~(2,7)) deca 〔8, 9, 1, 10-a,b, c〕pyrido〔4,3-a〕-acridin-6-en-9-ol-8-one

1INTRODUCTIONIntheO-demethyIationof7a-o-amino-phenyl-6,14-endo-ethenotetrahydrothe-baine,catalyzedbyhydrobromicacid,ifinhightemperatureandprolongedtime,anewcomPoundwithyie1dof17.9%wasfound,whosestructurecannotbedeferredfromthepreviousacid-catalyzedrearrangementof6,14-endo-ethnotetrahydrothe-baines(1-33.ItwascrystallizedfromanhydrousethanolsolutionanditsstructurewasdeterminedbyX-raycrystallography.2EXPERmENTALAcrystalwithdimensionsofO.3mmXO.4mmXO.5mmwasmountedonanEnraf-NoniusCAD4d…     

Über das 2, 4, 6-Trichlor-3-Bromphenol und das 2-Chlor-4, 6-Dibromphenol

Ohne Zusammenfassung     

Phase equilibria in the quaternary systems Li‖F,Cl,Br,CrO4 and Li‖F,Cl,Br,WO4

Phase equilibria in the quaternary systems Li‖F,Cl,Br,CrO₄ and Li‖F,Cl,Br,WO₄ were studied by differential thermal analysis. In these systems, the stability of continuous series of solid solutions based on lithium chloride and bromide is preserved. The number and compositions of crystallizing phases in the systems Li‖F,Cl,Br,CrO₄ and Li‖F,Cl,Br,WO₄ were confirmed by X-ray powder diffraction analysis.     

4-氯苯氧乙酸及4, 4′-bipy=4, 4′-联吡啶构筑的层状锌配合物的合成、晶体结构

水热条件下, 合成了一个新的锌(Ⅱ)配位聚合物[Zn(PCPA)₂(4, 4′-bipy)(H₂O)]_n(PCPA=4-氯苯氧乙酸, 4, 4′-bipy=4, 4′-联吡啶), 并通过元素分析、红外光谱、紫外光谱、热重分析、X-射线粉末衍射和X-射线单晶衍射对其进行了表征。锌(Ⅱ)分别与来自2个4, 4′-bipy的2个氮原子、3个4-氯苯氧乙酸的3个氧原子和1个水分子中的1个氧原子配位, 形成变形的八面体的配位构型。由于4-氯苯氧乙酸和4, 4′-bipy的桥联作用, 配合物在空间形成了二维层状结构, 在此二维层状结构中存在的O-H…O氢键起到了稳定结构的作用。     

Electrochemical determination of N,N-dimethyl-4-amino-4′-aminoazobenzene

N,N-Dimethyl-4-amino-4′-aminoazobenzene has been determined using differential pulse polarography. Fast-scan modification and linear-scan voltammetry at a hanging mercury drop electrode was used with a detection limit of less than 10⁻⁸ mol liter⁻¹. Differential pulse polarography was then used to analyze mixtures of the above depolarizer with azobenzene and N,N-dimethyl-4-aminoazobenzene, either directly, or after a TLC separation.