α－芳甲酰基烯酮二硫缩醛的新合成方法

以碳酸钾为碱，芳甲酰丙酮（１）与二硫化碳、卤代烃反应得到２－乙酰基－２－芳甲酰基烯酮硫代缩醛（２），２在乙硫醇钾作用下脱乙酰基生成标题化合物（３）。１→３的转化具有反应条件温和、产物产率高及对３中各种缩醛基均可通用等特点。     

从α－蒎烯直接催化酯化高选择性地合成乙酸正龙脑酯的研究－催化剂与反应机理初探

本文提出了新的硼酸类催化剂体系ＨＢ，用该体系对α－蒎烯与无水乙酸相互作用直接合成乙酸正龙脑酯作了较系统的研究。反应得到两种系列产物－酯化产物和异构化产物，酯化产物主要是乙酸正龙脑酯，葑醇酯和松油酯，异构化产物主要是莰烯、烯和松油烯等，总酯化产率为５０％以上，其中乙酸正龙脑酯为２０％以上，是至今从α－蒎烯直接合成乙酸正龙脑酯的最好结果。通过对产物的￣１ＨＮＭＫ图谱分析及动力学考察，确证反应主产物是正龙脑酯而不是异龙脑酯。文章对Ｈ＿２ＳＯ＿４、ＨＣｌＯ＿４、多聚磷酸（ＰＰＡ）和杂多酸（１２－磷钨酸）等催化剂进行了实验考察、对比和评述，表明了自制的ＨＢ催化剂体系具有高选择性合成乙酸正龙脑酯的显著优点，并对其反应机理作了初步探讨。     

钯(Ⅱ)-芳香氮碱-氨基酸三元配合物中的电子效应和芳环堆积作用

用pH-电位滴定法测定了Pd(L)(Aa)⁺三元配合物及相应的二元配合物,在25±0.5℃,30%的乙醇水溶液(体积分数),I=0.1(KNO₃)条件下的稳定常数及表征常数。其中L=邻菲罗啉(phen)、苯并咪唑邻菲罗啉(PIP)、邻菲罗啉-5,6-二酮(dophen)、2,9-二甲基邻菲罗啉(dmphen)和联吡啶3,3′-二羧酸(BDA);Aa为甘氨酸(gly)、苯丙氨酸(phe)、酪氨酸(tyr)、S-苄基-半胱氨酸(bcys)、谷氨酰胺(glu)和γ-谷氨酰-α-萘胺(gnapa)。从配合物配体间的电子效应和芳环堆积等观点对配合物的附加稳定性进行了讨论,并计算了电子效应和芳环堆积效应各自对三元配合物附加稳定性的贡献。     

荧光法研究金属络合物与脱氧核糖核酸的相互作用

研究了Tb(phen) 2 Cl3 ·H2 O·CH3 CH2 OH与小牛胸腺脱氧核糖核酸 (DNA)的作用方式 ,结果表明 :它们之间的作用存在两种模式 :嵌入与静电作用。运用Tb(phen) 2 Cl3 ·H2 O·CH3 CH2 OH作荧光探针初步研究了Ni(phen) 3 (ClO4) 2 ·3H2 O的两种手性对映体与DNA的相互作用 ,结果表明 :这两种对映体的作用存在差别     

M?ssbauer studies of the phase composition and microstructure of the La1-xCaxFeO3-y system as related to the reactivity of surface and bulk oxygen

The phase composition and microstructure of samples of the La_1-xCa_xFeO_3-y system prepared via a ceramic route were characterized by M?ssbauer spectroscopy. In all cases, iron was found in the 3+ state. The ordering of anion vacancies in the samples with the composition in the range of 0.8 > x ≥ 0.4, which corresponds to a microheterogeneous solid solution, generates new distorted octahedral and fivefold/tetrahedral sites revealed by two typical sextets. The disordering of this solid solution and small (10-100 ?) sizes of domains with a perovskite, braunmillerite or Grenier phase structure caused the appearance of a superparamagnetic doublet, which grows with the Ca content up to x = 0.8 but disappears in the sample of pure braunmillerite. The appearance of Fe cations in a distorted coordination correlates with the increased activity of the samples with a microheterogeneous structure in the CO catalytic oxidation and with their reducibility by H₂. This revised version was published online in August 2006 with corrections to the Cover Date.     

蒽环与苯环间的光化学Ⅰ.蒽环与苯环间分子内光致环加成反应

9 氯甲基蒽 ( 1 )与 3 ,5 二甲氧基苄醇 ( 2 )在相转移催化剂存在下反应生成 9 ( 3 ,5 二甲氧基苄基氧甲基 )蒽 ( 3 ) .( 3 )的苯溶液在紫外光照射下发生蒽环与苯环间的分子内 [4π + 4π]光致环加成反应 ,定量地生成多环化合物 ( 4 ) .( 4 )在热的作用下发生逆反应 ,定量地转化成原料 ( 3 ) .这种光致可逆反应可应用于制备光开关材料 .     

<Emphasis Type="Italic">Ab initio</Emphasis> study of small coinage metal telluride clusters Au<Subscript>n</Subscript>Te<Subscript>m</Subscript> (<Emphasis Type="Italic">n,m</Emphasis> = 1, 2)

The geometries of the most stable isomers of gold telluride systems AuTe, Au₂Te, and AuTe₂ are determined using the MP2 method. The aspect of gold—telluride interaction, the electron correlation, and relativistic effects on geometry and stability are investigated at the MP2 and CCSD(T) theoretical levels. The results show that the electron correlation and relativistic effects are responsible not only for gold—gold attraction but also for additional gold—telluride interaction. The gold—telluride interaction is strong enough to modify the known pattern of bare gold clusters. Both effects are essential for determining the geometry and relative stability of this type of systems.     

Mono- and di-substituted urea derivatives of cyclodiphosphazane: [ClP(μ-NBu)2PN(Me)CON(H)Me] and [Me(H)NCON(Me)P(μ-NBu)]2

The reaction of cis-[ClP(μ-N^tBu)]₂ with N,N′-dimethylurea leads to the formation of both mono- and di-substituted derivatives [ClP(μ-N^tBu)₂P(NMeCON(H)Me)] and [(μ-N^tBu)P(NMeCON(H)Me)]₂, instead of monomeric, dimeric or higher oligomeric macrocycles. The structure of [ClP(μ-N^tBu)₂P(NMeCON(H)Me)] shows rare non-bonded P?Cl and intermolecular hydrogen bonding interactions leading to a 2D-sheet like structure.     

Synthesis and characterisation of bis(pentafluorophenyl)antimony(V) cations, [(C6F5)2SbL3]

Pentacoordinate complex cations of the general formula [(C₆F₅)₂SbL₃]³⁺ stabilized as solid salts in combination with tetraphenylborate (BPh₄), tetrafluorobroate (BF₄) anions, where L=DMSO, Ph₃AsO, PyO, DMF, α-, β- and γ-picoline have been isolated. The newly formed complexes were characterized by elemental analysis, molar conductance measurements, solid-state IR and and NMR. From these results, a five-fold coordination around antimony was required.     

The photochemical interaction of polyphenylferrisiloxane with oligoorganosilanes

The photochemical interaction of polyphenylferrisiloxane with some oligoorganosilanes in benzene solutions has been studied by UV, IR, ESR, and Mössbauer spectroscopy. Silylene species formed during photolysis of oligoorganosilanes react with the high-spin iron(III) to reduce the latter to low-spin iron(II). The formation of the low-spin state of iron(II) was supported by measurements of the magnetic moments. The insertion of the silylene species into the polymer chain to form the Fe?Si bond occurs due to the photoreaction.