Preparation and Characterization of Pentafluoro-λ6-sulfanyldifluoromethane and Pentafluoro-λ6-sulfanyl-1,1,2,2-tetrafluoroethane

The pentafluorosulfanyl-λ⁶-perfluoroalkyl halides SF₅CF₂I, SF₅CF₂CF₂Br, and SF₅CF₂CF₂I were prepared for use in the syntheses of other SF₅-containing compounds. For example, new, convenient syntheses were developed for the hydro compounds SF₅CF₂H and SF₅CF₂CF₂H from the reduction of these iodides or bromides with either triethylborane or tributyltin hydride. Herein, more thorough spectroscopic analyses of the hydro compounds are presented, including multinuclear NMR and vibrational spectroscopy, mass spectrometry, and computational chemistry. Unfortunately, under the conditions tried, little to no evidence was obtained for potential SF₅(CF₂)_n- (where n=1 or 2) transfer reagents such as SF₅(CF₂)_nSi(CH₃)₃ or Cu(CF₂)_nSF₅.     

Organic Phosphorus-Suflur Compounds Derived from 1,3,2λ5,4λ5-Dithiaphosphetane 2,4-Disulfides. Synthesis and Properties

The results of author's research into the thiophosphorylating ability of 1,3,2⁵,4⁵-dithiadiphosphetane 2,4-disulfides in reactions with Group II, IV, V, and VI p-element derivatives containing E-X bonds (X = O, S, N) are summarized. New syntheses of organic phosphorus-sulfur compounds with P(S)SE (E = B, Al, C, Si, Ge, Sn, Ph, P, As, Sb, Bi, S) structural fragments are developed. Structural peculiarities and spectral and chemical properties of a series of representatives of these classes of organophosphorus compounds are discussed.     

Rearrangements in Spiro-λ4-sulfane Chemistry

The reactions of possible spiro-λ⁴-sulfane precursor diaryl sulfoxides with dehydrating agents have been studied resulting in the formation of cyclic anhydride, spiro-λ⁴-sulfane, cyclic sulfonium-ylide, lactam-sulfoxide, cyclic sulfonimide and cyclic sulfilimine type of intermediates or products. The structures of the intermediates or products depend on the functional groups attached to the aryl rings at ortho positions and on the reaction conditions applied.     

10-Oxo-10H-5λ,10λ-thianthren-5-ylideneamine as a probe for stereochemistry in the formation and amination of fluoro-λ-sulfanenitriles

The fluorination of 10-oxo-10H-5λ⁴,10λ⁴-thianthren-5-ylideneamine (2) with Selectfluor™ affords 5-fluoro-10-oxo-5,10-dihydro-5λ⁶,10λ⁴-thianthren-5-nitrile (4). The amination of 4 with morpholine gives 5-morpholino-10-oxo-5,10-dihydro-5λ⁶,10λ⁴-thianthren-5-nitrile (5). The stereochemical course of both reactions has been studied, while the configurations of their products, cis-isomer 4 and trans-5-morpholino-10-oxo-5,10-dihydro-5λ⁶,10λ⁴-thianthren-5-nitrile (trans-5) are elucidated by the use of X-ray crystallographic analyses.     

Highly Diastereoselective Synthesis of Anomeric β-O-Glycopyranosyl σ3λ3-and σ4λ5-Phosphorus Compounds

Abstract

A new method for the highly stereoselective synthesis of β-O-σ³λ³ and σ⁴λ⁴ phosphorus-substituted 2,3,4,6-tetrabcnzylglucose is presented. The β-diastereoselective synthesis of the carbohydrates containing σ³λ³ and σ⁴λ⁵ phosphorus groups could be accomplished via two main synthetic routes. The first involves the addition of the σ³λ³-phosphorus derivative 3 to the 2,3,4,6-tetrabenylglucose derivative 1 (αβ = 1:l) in toluene and triethylamine as a catalyst to provide the σ³λ³ phosphorus derivative 4 with practically 100% β-diastereoselectivity.     

Syntheses and Structure of Hexacoordinated Selenium (λ6-Selane) and Tellurium (λ6-Tellane) Compounds

The first isolation of bis(2,2′-biphenylylene)dichloro- and difluoro-perchalcogenuranes, [12–Se–6(C4F2)] (λ⁶-selane); [12–Te–6(C4X2), X = Cl, F] (λ⁶-tellane) and the corresponding tellurane Te-oxide dimer [12–Te–6(C4O2)]₂, and their crystal and molecular structures are described. Furthermore, on the basis of the difference between the 3c-4e bonds of the dodecet species and that of the decet species a new molecular orbital concept has been proposed on the 3c-4e bond of perchalcogenurane species [12–M–6, M = chalcogen atoms].     

λ-Shaped azomesogens with polar chloro- and nitro-substituents

A new homologous series of λ-shaped mesogenic azo esters with polar chloro- and nitro- substituents has been synthesised by attaching a rigid 2-chloro-4-nitrophenylazo group to a resorcinol moiety by a central azo linkage. Both phenolic hydroxyl groups are esterified by 4-n-alkoxybenzoyl groups. All the compounds synthesised have been characterised using a combination of elemental analysis and standard spectroscopic methods. The mesomorphic properties of the compounds have been determined by polarising optical microscopy and differential scanning calorimetry. The lower members of the series are non-mesogenic, the middle members exhibit a nematic mesophase, and higher members exhibit a smectic A mesophase. The effect of polar chloro-, nitro-, and long lateral aromatic substituents, on mesomorphism is discussed.     

有机化合物命名规则——λ-标志法

含有不同价态的同一元素原子的化合物命名法在有机化合物命名原则的基础上提出了化合物中存在不同价态同一元素原子时的命名方法,称为λ-标志法(lambda convention)。本法的初议曾发表于1982年,最后修订稿由国际纯粹和应用化学协会的有机命名小组于1983年讨论定稿,并发表于1984年。现节译于下,供国内化学工作者参考。     

Structural and bonding aspects of molybdenum tricarbonyl complexes of 2,4,6-tritertiarybutyl-1,3,5-triphosphabenzene,P3C3But3 and some λ3,λ3,λ5- and λ3,λ5,λ5-alkylated derivatives

The molecular structure of the previously reported compound [Mo(CO)₃(η⁶-P₃C₃Bu^t₃)] has been determined by a single-crystal X-ray diffraction study. Syntheses and molecular structures are also described for the structurally related compounds [Mo(CO)₃(η⁵-P₃C₃Bu^t₃)(Me)(Buⁿ)], [Mo(CO)₃(η⁵-P₃C₃Bu^t₃)(H)(Buⁿ)] and [Mo(CO)₃(η⁴-P₃C₃Bu^t₃(Me)(Buⁿ)(H)(O)Li(THF)₃]. Density functional calculations at the B3LYP/cc-pVDZ(-PP) and BP86/cc-pVDZ(-PP) levels have been carried out on the above complexes and the nature of the bonding between the different rings and molybdenum is discussed. ³¹P NMR spectroscopic evidence is presented for the existence of the novel complex [Mo(CO)₃(η⁶-P₃C₃Bu^t₃)PtCl₂(PEt₃)] in which the triphosphabenzene ring acts as an overall 8-electron donor to the two metal centres.     

非λ/4-非λ/4 SiO_2/TiO_2双层增透膜的设计与制备

通过TFCalc膜层设计软件设计了非λ/4-非λ/4双层增透膜体系.与λ/4-λ/4双层增透膜体系相比,非λ/4-非λ/4双层增透膜体系中内外层薄膜的折射率仅需满足n_1≥n_2(n_s/n_0)~(1/2)(其中n_1、n_2、n_s、n_0分别为内层膜、外层膜、基片和空气的折射率),即可通过调节内外层薄膜的厚度实现特定波长处的100%透过,扩展了膜层材料的选择范围.以酸催化TiO_2薄膜和SiO_2薄膜分别作为内、外层膜层材料,采用溶胶-凝胶浸渍-提拉法依次将TiO_2溶胶和SiO_2溶胶沉积在K9玻璃基片表面,最终形成SiO_2/TiO_2双层增透膜.实验结果表明,该双层增透膜具有与TFCalc模拟透过率曲线相吻合的实测透过率曲线,在中心波长处峰值透过率可达99.9%.该双层增透膜经耐摩擦和黏附性测试后峰值透过率基本保持不变,说明该增透膜具有良好的机械性能.这种同时具备高透过率和强机械性能的增透膜在太阳能电池等领域具有较广阔的应用前景.     

抗坏血酸对λ噬菌体紫外诱导过程的影响

本文通过研究抗坏血酸对紫外诱导λ噬菌体的影响 ,从自由基角度探讨了λ噬菌体紫外诱导过程的机制。结果表明抗坏血酸可有效抑制紫外对λ噬菌体的诱导 ,抑制效果具有明显的量效性。抗坏血酸浓度为 31 .8μmol/L时 ,抑制率高达 98%。细胞密度影响试验表明细胞密度为 4× 1 0 8cells/m L时 ,噬菌斑形成单位数最高。随着细胞密度的逐渐增加或减少 ,噬菌斑形成单位数均呈下降趋势。利用电子自旋共振及自旋捕捉技术 ,检测到紫外诱导过程中的自由基信号 ,其强弱与细胞密度密切相关 ,1 0 8cells/m L时自由基的信号明显强于 1 0 10 cells/m L。抗坏血酸的加入可消除所产生的自由基信号。由此可得出结论 :λ噬菌体的诱导裂解与自由基密切相关 ,抗坏血酸由于清除了所产生的自由基而对λ噬菌体的诱导裂解起到抑制     

An approach to the synthesis of 1,2λ-azaphosphinines

A novel approach to 1,2λ⁵-azaphosphinines has been elaborated. Aminophosphonium chlorides bearing a β-dialkylaminocrotonic nitrile residue react with N,N-dimethylformamide dimethylacetal to afford 1,2λ⁵-azaphosphinines.     

亚精胺诱导λ-DNA凝聚现象的AFM研究

生物体内DNA的紧密堆积存在方式与基因表达的自我调控机制有关 ,因此研究体内凝聚诱导物对DNA凝聚所起的作用具有重要意义 .采用原子力显微镜(AFM )研究了这一体系 .研究表明 :亚精胺可直接诱导λ DNA形成一种特殊的结构———环形凝聚体 ;环形凝聚体的形成受动力学因素 (时间 ,浓度 )影响较大 ;环形凝聚体由纳米级小颗粒紧密排列而成 ;凝聚机制可能是以这些颗粒为组成单元的螺旋盘绕过程 .所得结论对生物体内DNA凝聚过程的理论研究具有重要意义     

Application of alkoxy-λ6-sulfanenitriles as strong alkylating reagents

Alkoxy-λ⁶-sulfanenitriles were found to be versatile alkylating reagents toward various nucleophiles bearing at least one proton such as methanol, phenol, thiophenols, carboxylic acids, p-toluenesulfonic acid, hydrochloric acid, and primary and secondary amines. Reactivity of the alkoxy group of the λ⁶-sulfanenitriles showed an opposite trend to the usual S_N2 character, i.e. Me ( 1a ), Pr ( 1b ), and Bu ( 1d ) ≪ i-Pr ( 1c ). In the presence of p-TsOH, alkyl tosylates were predominantly formed instead of the alkylation products of nucleophiles. In addition, even a sterically hindered substrate, neopentyloxy-λ⁶-sulfanenitrile, was found to undergo an S_N2 reaction toward thiophenol without any rearrangement product to give neopentyl phenyl sulfide in good yield. © 2004 Wiley Periodicals, Inc. Heteroatom Chem 15:193–198, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20006     

锌离子在λ—MnO2中的电化学嵌入

由于二氧化锰氧原子与中心锰原子所组成的八面体[MnO_6],可按照不同的方式连接,形成β,γ和δ-MnO_2等多种结构形式。Hunter用稀酸处理LiMn_2O_4得到具有尖晶石结构的λ-MnO_2。这种结构具有相互连通的三维离子迁移隧道。显然它比仅含一维隧道的β-     

Polarity of [sgrave]3,λ5-Phosphoranes

Abstract

Tricoordinated pentavalent phosphorus compounds- [sgrave]³,λ⁵-phosphoranes-present a new field in unusually (low) coordinated phosphorus chemistry. Our current interest in these compounds is stimulated by the possibility of actual determination of unknown phosphorus bond polarities, using electrical methods in subsequent investigations of the spatial and electronic structure of [sgrave]³,λ⁵ -phosphoranes. We have studied the series of bis(imino)phosphoranes by the method of dipole moments R²N=P (R¹)=NR³ (I-VI) R¹ R² R³,^μexp.^{(D): (I) N}(^SiMe ₃)₂, ^SiMe ₃, SiMe₃, 2.16; (11) t-Bu, t-Bu, 2.36; (111) N(SiMe₃)₂, SiMe₃, t-Bu, 2.26; (IV) 2,4,6-Me₃C₆H₂, t-Bu, 2,4,6-t-Bu₃C₆H₂, 2.44; (V) t-Bu(Me₃Si)N, t-Bu, t-Bu, 2.74; (VI) c-2,2,6,6-Me4C5H6N, SiMe₃, SiMe₃, 2.82 and defined P=N bond polarity (3.14D). Dipole monents (I-VI) are described by the given values, the group moments R-P and R-N were previously found from dicoordinated phosphorus compounds. The tendency of increasing ^μexp, with the growth of n,Π-donor abilities of ^μexP,₁ substituent R in row (I-III)-(V)-(VI) is possibly caused by the increase of the conjugative effect contribution in stabilization of the 4-electron 3-centre Π-system N=P=N.     

石墨烯纳米孔的制备及λ-DNA穿孔初步研究

纳米孔测序是有可能实现"$1,000 Genome"目标的技术之一.近年来,研究较多的纳米孔有蛋白质纳米孔和硅基材料的固态纳米孔.蛋白孔寿命比较短,而基于硅基底的固态纳米孔深度显著超过单链DNA相邻碱基的间距,所以,无法实现DNA的单个碱基的分辨.作者用聚焦离子束先制造氮化硅基底,并在该基底上铺设石墨烯,再用聚焦电子束刻蚀石墨烯,获得直径10 nm以下的纳米孔,初步分析了DNA穿越纳米孔时产生的电信号及穿孔噪音,向单层石墨烯纳米孔测序DNA迈出了一步.     

LaMn1—xCoxO3—λ催化剂的XPS研究

用柠檬酸络合法制备了LaMn_(1-x)Co_xO_(3-λ)系列稀土复合氧化物。用XPS技术研究了它的表面、体内组态和结构变化及锰和钴含量对La 3d_(5/2)特征峰和Shske-up伴峰的影响。认为α-O是催化剂中的活性氧种。用氩离子剥离技术研究了LaMn_(1-x)Co_xO_(3-λ)体系,观察到锰在表面的偏析作用随x的减小而增大。     

Thermal Behavior of Pyridinium Salt of 2,4-Dimer-Capto-2,4-Dithioxo-1,3-Bis(Trimethylsilyl)-1,3-Diaza-2λ5, 4λ5-Diphosphetidine

Abstract

The reaction of P₄S₁₀with PSCL₃ in pyridine leads to Py.PS₂Cl (1). This substance yields by the reaction with hexamethyldiailazane in molar ratio 1:l a new subatance that was identified as pyridiniwn salt of 2,4-dimercapto-2,4-dithioxo-1,3-bis(trimethylsilyl)-1,3-diaza-2λ⁵,4λ⁵-diphosphetidine (PYH)₂/S₂P(NSiMe₃)₂PS₂/ (I). (2).