R-(—)-1-氯甲基-4-乙基-2,8,9-三氧杂-5-氮杂-1-硅杂三环[3,3,3,0~(1.5)]十一碳烷的晶体结构

杂氮硅三环是一类具有特殊生理活性的新型有机硅化合物,有关其合成及性质在近20年中已有大量报道。特别是当R为氯甲基时,该化合物的生理活性很高,用它制成的药膏已用来治疗脱发及伤口愈合。因此,1-氯甲基杂氮硅三环(Ⅰ)的分子结构引起了人们的关注,先后有人报道了(Ⅰ)及1-氯甲基-3,7-二甲基,1-氯甲基-3,7,10-三甲基     

双波长K系数—标准加入吸光光度法同时测定锰和锌

研究应用双波长K系数—标准加入吸光光度法同时测定锰和锌二组分混合物.试验确定了锰和锌测定中K_(Mn)与K_(Zn)的回归方程.对合成试样、人发试样测定,结果满意.     

Two new sesquiterpene lactones with the sulfonic acid group from Saussurea lappa

Two new sesquiterpene lactones with the unusual sulfonic acid group, 13-sulfo-dihydrosantamarine (1) and 13-sulfo-dihydroreynosin (2), have been isolated from the roots of Saussurea lappa C. Their structures, including the absolute configurations, were elucidated by spectroscopic methods.     

环己烯和2-甲基戊烯-1在几种Y型分子筛上的吸附量热研究

用SETARAM热流式量热计测定了环己烯和2-甲基戊烯-1于室温下在NaY、CaY、R_EY和HY等几种分子筛上的微分吸附热。我们又用Benson基团加合法计算得到了生成仲碳离子和叔碳离子时的吸附热。根据实验测得的于不同吸附量时环己烯和2-甲基戊烯-1的吸附热之差值, 对它们在上述几种Y型分子筛上的吸附机理进行了讨论。     

Crystal Structure,Electrochemical Properties and Third-order Nonlinear Optical Response of 4-Methyloxy benzaldehyde Thiosemicarbazone and Its Copper(Ⅱ)Complex

Thecurrentsurgeofinterestinthefield0fnon-linearoptics(NL0)isderivedbothfromaquestforafundamentalunderstanding0fthenon-linearprocess,anditSimPortanceinthetechn0logyofphotonics.Amongnon-linearphen0mena,thethird-ordernon-linearophcsoccuPyanimPortantp0sihonbecauseitprovidesthemechanicsforophcalswitching,ophcallogic,andreal-hmeholograPhy"'.0rganicmaterialwithextendednconjugahonsandlargeRdelocalizahonsarewellknownastheimPortantmaterialsofachievinglargethird-ordernonlinearihes3.ForexamPle,thiosen…     

A practical synthetic route to 4′-alkylaristeromycin derivatives: 4′-methylaristeromycin

(−)-(1S,4R)-4-Hydroxy-2-cyclopenten-1-yl acetate provided a convenient entry point for a 16-step chiral preparation of 4′-methylaristeromycin. This procedure is adaptable to a number of carbocyclic nucleosides with a diversity of substitution at C-4′ and C-5′ and a variety of heterocyclic bases.     

双电层相互重叠时蒙脱胶体表面阴离子的负吸附

本文用Ag-AgCl电极判断平衡,测定双电层处于不同重叠程度下肢体表面阴离子的负吸附量Γ.结果表明,胶体表面双电层相互重叠程度可由两胶体表面间的中点电位φd与外Helmhotz面处的电位φd之比表征;阴离子负吸附随双电层重叠程度和电解质浓度的增加而显著减小.     

动态法测定耐硫甲烷化催化剂的有效导热系数

本文采用动态法原理，用单丝直径为０．２ｍｍ的铜－录铜热偶作为测温元件，在３１３－５３３Ｋ温度区间，测定了耐硫甲烷化催化剂的有地热系数。用石蜡和锡作为参比物，对所用仪器及实验方法进行了可靠性检验。实验表明，动态法是测定多孔硫化物催化剂导热系数的有效方法。其精度符合工程要求，亦能用于其它材料导热系数的测定。对所测数据用单纯形方法优化拟合，得到大于３５３Ｋ范围内的有效导热系数的经验公式。     

Olefin oxygenation by the hydroperoxide adduct of a nonheme manganese(IV) complex: epoxidations by a metallo-peracid produces gentle selective oxidations

The reactive intermediates and mechanisms of oxygenation of olefins by manganese complexes were investigated by treating olefins with newly synthesized [MnIV(Me2EBC)(OH)2](PF6)2 in the presence and absence of peroxide and by studying its catalytic epoxidation reaction in normal aqueous solution and, individually, with isotopically labeled H218O, 18O2, and H218O2. The manganese oxo species is not the reactive intermediate for the oxygen transfer process mediated by this manganese complex. A novel manganese(IV) peroxide intermediate, MnIV(Me2EBC)(O)(OOH)+, was captured by mass spectrometry and is proposed as the intermediate that oxygenates olefins in this catalytic system.     

Study on multimers and their structures in molecular association mixture

Self-association system of(R)-1,3-butanediol in dilute carbon tetrachloride(CCl4)solution is studied as a model of molecular association mixture.Analysis methods including FSMWEFA(fixed-size moving window evolving factor analysis)combined with PCA(principal component analysis),SIMPLISMA (simple-to-use interactive self-modeling mixture analysis),and ITTFA(iterative target transformation factor analysis)are adopted to resolve infrared spectra of(R)-1,3-butanediol solution.Association number and equilibrium constant are computed.(R)-1,3-butanediol in dilute inert solution is determined as a monomer-trimer equilibrium system.Theoretical investigation of trimer structures is carried out with DFT(density functional theory),and structural factors are analyzed.