A metallo-capped polyrotaxane containing calix[4]arenes and cyclodextrins and its highly selective binding for Ca2+

A water-soluble nanometer-scale metallocapped polyrotaxane has been prepared by the inclusion complexation of azo-calixarenes with metallo-bridged bis(beta-CD)s, displaying highly selective binding for Ca(2+).     

Infrared and electronic spectra of copper (II) complex of maleonitriledithiolate and 4,4'-dimethyl-2, 2'-bipyridine and their theoretical studies

The molecular structure and binding, as well as infrared and electronic spectroscopic properties for the title complex Cu(mnt)(dmbpy)(mnt(2-)=maleonitriledithiolate, dmbpy=4,4'-dimethyl-2,2'-bipyridine) were studied in this paper. With semi-empirical PM3 and non-empirical DFT (B3LYP/6-311G*) methods, the molecular geometry of the complex was optimized and corresponding vibrational spectra in the gaseous state were obtained. The calculated results derived from DFT were more reasonable than those from PM3. The point group of Cu(mnt)(dmbpy) in isolated gaseous state was C(2), in which Cu(II) adopted a distorted tetrahedral geometry and the dihedral angle between the N(2)Cu and S(2)Cu planes was about 29.814 degrees. And a complete assignment to the IR spectra of such a complicated molecule was exhibited. With ZINDO/S method an electronic spectrum was calculated. The results showed that the calculated values generally agreed with the observed ones. And a detailed explain was made on its electronic spectra.     

Fluorous distannoxane-catalyzed acetylation of alcohols in heterogeneous single fluorous solvent system

Acetylation of alcohols with an equivalent amount of acetic anhydride is feasible in the presence of fluorous distannoxane catalyst in heterogeneous single fluorous system. The fluorous layer containing catalyst can be recycled and reused at least 10 times.     

Aging of poly(2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylenevinylene)/toluene solutions and subsequent effects on luminescence behavior of cast films

Morphological effects in luminescence properties of a representative semiconducting polymer, poly(2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylenevinylene) (MEH-PPV), has recently attracted much attention. Previous studies indicated that short-term heat treatment of solution-cast MEH-PPV films may result in the formation of mesomorphic order that is responsible for the "red" emission around 640 nm, in contrast to the single-chromophore "yellow" emission near 590 nm from the disordered matrix. On the basis of microscopic and spectroscopic evidence for films cast from freshly prepared and aged solutions, here we show that prolonged storage of MEHyellowPPV solutions at room temperature or lower may result in retardation of the thermally induced mesophase formation in the subsequently cast films. According to small-angle neutron scattering and differential scanning calorimetric observations over aged MEH-PPV/toluene solutions, we propose that the suppressed transformation into mesomorphic order is due to further development of nanocrystalline aggregates that serve as physical cross-links among MEH-PPV chains in the solution state upon long-term storage. These solvent-induced nanocrystalline aggregates, however, do not exhibit new spectroscopic features beyond the suppression of "red" emission at 640 nm from the mesomorphic phase.     

Synthesis of 2‐Dihydrooxadiazolinyl Chromones

Reactions of the substituted 2‐formyl chromones with aroylhydrazines gave corresponding 2‐(aroylhydrazonomethylidyne) chromones. Then 2‐(3′‐acetyl‐5′‐aryl‐2′,3′‐dihydro‐1′,3′,4′‐oxadiazol‐2′‐yl) chromones were prepared by these 2‐(aroylhydrazonomethylidyne) chromones under refluxing with Ac₂O. All target compounds were characterized through elemental analysis and IR, ¹H NMR, MS.     

A Novel Method for Quantification of Circulating DNA in Serum by Capillary Zone Electrophoresis

In this paper, we first presented a novel method for quantification of circulating DNA in human serum based on capillary zone electrophoresis with laser-induced fluorescence detection (CZE-LIF). The serum was digested by proteinase to release free DNA, and then CZE-LIF system was used for the quantification of total circulating DNA. This method was successfully used to quantify the circulating DNA levels in sera from healthy individuals and certain cancer patients.We found the significantly elevated circulating DNA levels in certain prostate cancer patients. Our results demonstrated that CZE-LIF system has good linearity, excellent sensitivity (0.5 ng/mL DNA),satisfactory reproducibility (RSDs in one day and between days were both less than 5%) and reliability, and is well suitable to the quantification of the circulating DNA in human serum or plasma.     

Prediction of retention indexes. III. Silylated derivatives of polar compounds.

Polar compounds containing hydroxyl, amino and carboxyl groups, singly or in combination, can be chromatographed after the polar functional groups are silylated. The silylated derivatives of acids, alcohols, amines, diols, amino alcohols, amino acids are shown to behave chromatographically as hydrocarbons, and their retention indexes can be readily predicted from their base values. The column difference, namely, the difference between the retention indexes of the analyte on polar and non-polar columns is minimal for the silylated derivatives in comparison to that observed for the underivatized analytes. This minimal column difference is attributed to the hydrocarbon-like chromatographic characteristics of the silylated derivatives. The retention indexes of the silyl derivatives appear to correlate with the atom number Z of the analyte.     

Application of NMR SHAPES screening to an RNA target

Several NMR screening techniques have been developed in recent years to aid in the identification of lead drug compounds. These NMR methods have traditionally been used for protein targets, and here we examine their applicability for an RNA target. We used the SHAPES compound library to test three different NMR screening methodologies: the saturation transfer difference (STD), the 2D trNOESY, and the WaterLOGSY experiments. We found that the WaterLOGSY experiment was the most sensitive method for our RNA target, the P4P6 domain of the Tetrahymena thermophila Group I intron. Using the WaterLOGSY experiment, we found that 23 of the 112 SHAPES compounds interact with P4P6. To identify which of these 23 hits bind through nonspecific interactions, we counterscreened with a linear duplex RNA control and identified one of the SHAPES compounds as interacting with P4P6 specifically. We thus demonstrated that the WaterLOGSY experiment in combination with the SHAPES compound library can be used to efficiently find RNA binding lead compounds.     

Adsorption of bovine serum albumin on nanosized magnetic particles

A new model was proposed to predict the adsorption equilibrium of mixtures composed of supercritical gases. The adsorbed phase was visualized as a two-dimensional nonideal compressed gas. Pore size distribution was used to describe the energetic heterogeneity of the surface, and the two-dimensional virial equation was used as the local adsorption isotherm. The new model obtained is thermodynamically rigorous because it reduces to Henry's law as pressure approaches zero. The prediction performance of the new model was verified and compared with other models using the experimental data of a ternary mixture of CH4/N2/H2 and two binary mixtures of CH4/C2H4 and CH4/N2. Better performance was shown for all systems tested.