苯乙烯基吡啶类化合物几何结构与光谱的理论研究

采用量子化学密度泛函理论(DFT)方法分别在B3LYP/6-31G*, 6-31G**, 6-31＋G*水平上对苯乙烯基吡啶类化合物进行计算研究. 通过在相同水平下的振动频率分析发现苯乙烯基吡啶类化合物具有C₁对称性, 酯基的碳氧原子与苯环形成不同的离域大π键, 空间位阻和共轭效应使得两苯环处于两个不同平面, 二面角在60°与62°之间. 使用含时密度泛函理论(TD-DFT)方法计算第一激发态的电子垂直跃迁能, 得到最大吸收波长λ_max. 计算结果表明末端烷基链的长度对该类化合物的几何结构与振动光谱、电子光谱无影响.     

Bi4PMo(12)O(49)催化剂的性质及其在丙烷选择氧化中的活性

从钼磷酸出发制备了Ｂｉ４ＰＭｏ１２Ｏ４９催化剂，ＩＲ及ＸＲＤ分析结果表明，高温焙烧后其基本组成为α－Ｂｉ２Ｍｏ３Ｏ１２／ＭｏＯ３，考察了该催化剂对丙烷的选择氧化生，ＥＳＲ及ＸＰＳ测定结果表明，反应后催化剂中Ｍｏ＾５＋的含量明显增加，这暗示着反应物种吸附在Ｍｏ＾６＋上，而Ｂｉ则为气相氧的入口。     

二硫代氨基甲酸螯合树脂化学修饰电极的制备及银离子的测定

将纯石墨电极经三氧化二铝抛光与浓硝酸和浓硫酸(1+1)混合酸使其极性化,之后于1 g·L-1聚氯乙烯(PVC)环己酮溶液10μL中浸渍片刻,取出,用红外灯照射烘干30 min,冷却后,将电极置于含有哌嗪、K3PO4及二甲基甲酰胺(DMF)(2:1:8)的混合液中使其反应;最后在氢氧化钠存在下与二硫化碳反应,用水洗至中性,即制成修饰有二硫代氨基甲酸螯合树脂的石墨电极,将其用于银的测定。与未修饰的电极相比此电极具有较高的灵敏度和较好的选择性,在1．0×10-8～1．0×10-5mol·L-1范围内,峰电流与浓度呈线性关系,检出限为5．0×10-9mol·L-1。     

原位氧化还原沉淀水热合成法制备LixMn2O4尖晶石

Li xMn2O4尖晶石是新一代的锂离子二次电池正极材料 [1], 其合成方法对材料的电化学性质影响很大[2].常规合成大多采用高温固相反应法, 此法具有反应温度高, 反应时间长, 容易产生缺陷和产物不纯净等缺点, 导致所合成的锂离子二次电池正极材料的性能较差. 目前用水热合成法制备电池正极材料Li xMn2O4尖晶石尚未见文献报道. 本文在常规水热合成法的基础上采用原位氧化还原沉淀水热合成法 [3]制备前驱物, 该法合成条件更温和, 而且使材料的综合性能得到了改善和提高.      

Preparation of a novel self-assembling nonlinear optical (NLO) polymer film

A novel self-assembling crosslinking second harmonic generation nonlinear optical (SHG/NLO) film with high SHG coefficient (2×10-7 e.s,u.by IR dichroism) was prepared by morecular design and "in-situ poling and sol-gel process".The content of the NLO chromophore (S)-(-)-1-(4)-mtrophenyl-2-pyrrolidinemethanol (NPP) is as high as 50 mol% since NPP molecules probably disperse in the film at a molecular level The film is rigid,uni form and transparent.This designed clathrate supermolecular structure was poved by IR,atomic force microseopv (AFM) and differential scanning calorimetry (DSC) detection.The title film exhibits a long-term temporal stability with 95% of the initial value of SHG coefficient maintained even after 20 d at 65℃(by UV spectroscopy)     

Total synthesis of methyl protodioscin: a potent agent with antitumor activity

Methyl protodioscin (1), otherwise known as 3-O-[alpha-L-rhamnopyranosyl-(1-->2)-[alpha-L-rhamnopyranosyl-(1-->4)]-beta-d-glucopyranosyl]-26-O-[beta-D-glucopyranosyl]-22-methoxy-25(R)-furost-5-ene-3 beta,26-diol, has been synthesized for the first time from diosgenin through nine steps in an overall yield of 7.8%.     

RAMAN STUDIES OF STRUCTURAL PHASE TRANSITION IN[n-C_(11)H_(28)NH_8]_2ZnCl_4

The perovskite type of compound [n-C_(11)H_(23)N_3]_2ZnCl_4(abr.C_(11)Zn)exhibits two solid-solid phasetransitions at T_(c1)=298.7 K and T_(c2)=360.1 K.A temperature dependence study of Raman spectra of C_(11)Znprovides the evidence of occurence of the structural phase transition related to the dynamics of thealkylammonium ions.The room temperature phase is ordered and contains the all-trans alkyl chains.Theintermediate temperature phase presents a partial conformational disorder and liquidlike state of allconformational disorder occurs at high-temperature phase.     

两种结构钼磷酸的催化氧化行为

考察了Dawson与Keggin结构钼磷酸的催化氧化行为,并与结构特性进行了关联,结果发现,Dawson结构的杂多酸对氧化脱氢及插入氧反应均有更高的活性。     

Indirect Determination of Captopril with Sodium Nitrate and Thiocyanate by Floatation Separation of Copper

A new method for indirect determination of captopril (CPT) with NaNO₃ and NH₄SCN by floatation and separation of copper has been studied. In the weak acid, a small amount of Cu(II) can be reduced to Cu(I) by CPT, then Cu(I) reacted with the SCN, which can float on the surface of the liquid phase with NaNO₃. A good linear relationship is observed between the floatation yield (E%) of Cu(II) and the amount of captopril. The linear range is 2?32 mg/L. On the ground, captopril can be indirectly determined by determining E(%) of Cu(II). The method is simple, rapid, reliable and has good selectivity. The developed method can be applied to indirect determination of captopril with satisfactory results.     

Synthesis of (s)-(-)-Benzyl-2-tert-butoxycarbonyl amino-4-iodobutyrate

The proteinogenic (-amino acids constitute an important section of the "chiral pool", being inexpensive in the L-form (but available if necessary as the D enantiomers), structurally varied and chemically versatile1, they are useful starting materials for chiral reagents, auxiliaries and ligands2. Any high-yielding transformation of an (-amino acids which proceeds without racemization is thus of potential importance, especially if it generates another reactive center and may be applied to the s…