拓扑指数F(′F)与气相色谱保留指数RI的相关性研究

用结构参数构成的矩阵定义了拓扑指数Ｆ（′Ｆ），计算了１０个系列９４个分子的 Ｆ（′Ｆ）值。发现Ｆ（′Ｆ）与这些化合物的气相色谱保留指数有好的相关性．相关系数均在０．９７ 以上。     

High performance liquid chromatographic determination of N-nitrosoamines by pre-column fluorescence derivatization with acridone-N-acetyl chloride

A sensitive high performance liquid chromatographic method for the determination of N-nitrosoamines with pre-column fluorescence derivatization has been developed. N-nitrosoamines are first changed into secondary amines using denitrosation reagent, then react with acridone-N-acetyl chloride (ARC-Cl) to produce corresponding secondary amine derivatives, which exhibit a strong fluorescence. Maximum emission for ARC derivatives is 430 nm (lambda(ex) 404 nm). The labelled derivatives are very stable, less than 4% decomposition occurs after heating at 40 degrees C for 24 h. Fluorescence intensities of derivatives are higher in neutral and alkaline than in acidic solutions. This method, in conjunction with a multi-gradient program, offers a baseline resolution of the ARC derivatives from a linear acetonitrile gradient. Separation is carried out on a reverse phase C(18) column. Derivatization and chromatographic conditions are optimized. The relative standard deviation (n=6) at an analytical concentration of 10 pmol of each N-nitroamine is less than 4.5%. The detection limits at the fmol level. The method described is also suitable for analysis of other amino compounds in different biological samples.     

Adsorption of formaldehyde on Pt(111) and Pt(100) electrodes: cyclic voltammetry and scanning tunneling microscopy

The adsorption of formaldehyde (HCHO) on Pt(111) and Pt(100) electrodes was examined by cyclic voltammetry (CV) and in situ scanning tunneling microscopy (STM) in 0.1 M HClO(4). The extent of HCHO adsorption at both Pt electrodes was evaluated by comparing the CVs, particularly for the hydrogen adsorption and desorption between 0.05 and 0.4 V, obtained in 0.1 M HClO(4) with and without HCHO. The adsorption of HCHO on these Pt electrodes was significant only when [HCHO] >/= 10 mM. Adsorbed organic intermediate species acted as poisons, blocking Pt surfaces and causing delays in the oxidation of HCHO. Compared to Pt(111), Pt(100) was more prone to poisoning, as indicated by a 200 mV positive shift of the onset of HCHO oxidation. However, Pt(100) exhibited an activity 3 times higher than that of Pt(111), as indicated by the difference in peak current density of HCHO oxidation. Molecular resolution STM revealed highly ordered structures of Pt(111)-( radical7 x radical7)R19.1 degrees and Pt(100)-( radical2 x radical2) in the potential region between 0.1 and 0.3 V. Voltammetric measurements further showed that the organic poisons produced by HCHO adsorption behaved differently from the intentionally dosed CO admolecules, which supports the assumption for the formation of HCO or COH adspecies, rather than CO, as the poison. On both Pt electrodes, HCHO oxidation commenced preferentially at step sites at the onset potential of this reaction, but it occurred uniformly at the peak potentials.     

温度对萘在Pluronic胶束水溶液中增溶的影响

研究结果表明 ,温度升高促使Pluronic分子形成更加疏水并且具有较大内核的胶束 ,使萘和胶束内核的亲和力增强 ,从而促进萘的增溶。在所考察的F1 0 8和P94二种Pluronic胶束体系中 ,温度对增溶的促进作用 ,前者比后者更为明显。     

Effects of compositions on the stability of polyols-in-oil-in-water (P/O/W) multiple emulsions

Polyols-in-oil-in-water (P/O/W) multiple emulsions were successfully prepared by using polyols as inner aqueous phase to avoid instabilities caused by water. The influence of polyols, oils and emulsifiers on the morphology and stability of P/O/W multiple emulsions were studied and the stability mechanisms of this new kind of multiple emulsions were also explored. Glycerol that has the worst solubility in oil phase contributed to the formation of stable inner droplets which agree with the Ostwald Ripening theory. Mineral oil worked well with the system proving that oils possessing similar solubility parameters with the hydrophobic group of emulsifiers benefited for system stability. Several typical surfactants had been investigated in this article, and it turned out that emulsifiers Cetyl PEG/PPG-10/1 Dimethicone and the block copolymer Poloxamer 407 were suitable for the P/O/W system. The stability of the system affected by different compositions was evaluated based on microscopic observation and rheological measurements. The novel multiple emulsions will provide enlightening recommendations for future investigations and applications in cosmetic, food and pharmaceuticals, including drug delivery and the encapsulation of hydrophilic actives and actives that are soluble in polyols.     

Intermolecular Charge‐Transfer Transition Emitter Showing Thermally Activated Delayed Fluorescence for Efficient Non‐Doped OLEDs

A novel molecular model of connecting electron‐donating (D) and electron‐withdrawing (A) moieties via a space‐enough and conjugation‐forbidden linkage (D‐Spacer‐A) is proposed to develop efficient non‐doped thermally activated delayed fluorescence (TADF) emitters. 10‐(4‐(4‐(4,6‐diphenyl‐1,3,5‐triazin‐2‐yl) phenoxy) phenyl)‐9,9‐dimethyl‐9,10‐dihydroacridine (DMAC‐o‐TRZ) was designed and synthesized accordingly. As expected, it exhibits local excited properties in single‐molecule state as D‐Spacer‐A molecular backbone strongly suppress the intramolecular charge‐transfer (CT) transition. And intermolecular CT transition acted as the vital radiation channel for neat DMAC‐o‐TRZ film. As in return, the non‐doped device exhibits a remarkable maximum external quantum efficiency (EQE) of 14.7 %. These results prove the feasibility of D‐Spacer‐A molecules to develop intermolecular CT transition TADF emitters for efficient non‐doped OLEDs.     

The pH-controlled[2]or [3]pseudorotaxanes based on stilbene dye SD⊂CB[7]

We studied characteristics of [2] or [3]pseudorotaxanes based on stilbene dye SD?CB[7] . In neutral or weak alkaline conditions, SD could be encapsulated inside the stilbene site of CB[7] with 1:1 stoichiometry, whereas, with the pH changing to acidity, the hydrogen bonding between the carboxyl group and the carbonyl of CB[7] maked another CB[7] molecule include into hexanoic acid site, these processes were confirmed by fluorescence spectra,UV–Vis spectra and 1H NMR.     

TBHP/TBAI-mediated oxidation of thiophenols for the synthesis of tert-butyl arylsulfinates

A novel and efficient TBHP/TBAI-mediated oxidation of thiophenols is described. The reactions proceeded smoothly to give tert-butyl arylsulfinates in up to 82% yield with good functional group compatibility under mild conditions.     

C_(12)-s-C_(12)·2Br和C_(12)E_n混合水溶液的胶团化行为

季铵盐二聚表面活性剂C12-s-C12·2Br(s=2、3、4、6)和非离子表面活性剂C12E10或C12E23在水溶液中生成混合胶团.其临界胶团总浓度cmcT值介于二元复配体系中各组分的临界胶团浓度cmc01和cmc02之间.当添加少量非离子型表面活性剂(在水溶液中的摩尔分数α2=0.1)时,混合胶团中C12E10或C12E23的摩尔分数均已超过0.35;随着溶液中非离子型表面活性剂含量的增大,混合胶团中逐渐以C12E10或C12E23成分为主.     

Preparation of polystyrene/silica nanocomposites by radical copolymerization of styrene with silica macromonomer

A two-stage process has been developed to generate the silica-based macromonomer through surface-modification of silica with polymerizable vinyl groups. The silica surfaces were treated with excess 2,4-toluene diisocynate (TDI), after which the residual isocyanate groups were converted into polymerizable vinyl groups by reaction with hydroxypropylacrylate (HPA). Thus, polystyrene/silica nanocomposites were prepared by conventional radical copolymerization of styrene with silica macromonomer. The main effecting factors, such as ratios of styrene to the macromonomer, together with polymerization time on the copolymerization were studied in detail. FTIR, DSC and TGA were utilized to characterize the nanocomposites. Experimental results revealed that the silica nanoparticles act as cross-linking points in the polystytene/silica nanocomposites, and the glass transition temperatures of the nanocomposites are higher than that of the corresponding pure polystyrene. The glass transition temperatures of nanocomposites increased with the increasing of silica contents, which were further ascertained by DSC.