A comparison of phosphaferrocene and phospharuthenocene ligands in Rh+-catalysed enamide hydrogenation reactions: superior performance of the phospharuthenocene

Enantiopure Cp*-substituted 3,4-dimethyl-5-phenylphosphametallocene-2-methanols (M=Fe, Ru) have been prepared from the corresponding 2-carboxy-(-)-menthylphospholide anion and elaborated into 2-CH(2)PPh(2) phosphametallocenes (13: M=Fe; 14: M=Ru) and 2-CH(2)PtBuR substituted phospharuthenocenes (R=tBu, Me). The crystal structures of complexes [Rh(1,5-cod)(eta(2)-L)](+)BF(4)(-) (L=13, 14) reveal significantly different aryl group configurations. Comparative studies of the hydrogenation of para-substituted N-acetylcinnamate esters with these pre-catalysts show a superior performance for the phospharuthenocene derivative in terms of both rate and enantioselectivity.     

2-substituted benzofuran fragment ion formation in the electron ionization mass spectra of 6-alkyl- and 6-aryldibenzo(d,f)(1,3)dioxepine derivatives. 1. Spirocyclization of the molecular ions in the gas phase

The formation of 2-substituted benzo[b]furan ions in the electron ionization (EI) mass spectra of a series of 6-alkyl- and 6-aryldibenzo(d,f)(1,3)dioxepines has been studied by means of exact mass measurements and multiple-stage mass spectrometry conditions using an ion trap mass spectrometer. The proposed mechanism of formation of benzo[b]furan ions requires the formation of a spirocyclic cyclohexadienone system, which undergoes elimination of a cyclopentadienone molecule. A parallel with the chemical conversion of arylmethyl-substituted dibenzo(d,f)(1,3)dioxepines into an analogous spirocyclic system was also underlined.     

DL—丙氨酸与氢氧化铜固相配位反应的热化学研究

研究固态化学反应对合成化学、理论研究以及工业生产都有重要意义,南京大学忻新泉等人在室温或低温温度条件下固相配位反应的合成及机理研究方面做了许多有意义的工作[1,2],为使低温温度固相合成法最终走向应用作了积极贡献。由于固相配位反应的热效应难以直接测定,热化学...     

Simultaneous construction of a polyether backbone and a variety of keto side chains by three‐component polycondensation: An improved method for the use of a variety of silyl enol ethers

For the synthesis of polyethers with a variety of keto side chains in a one‐step reaction, the three‐component polycondensation of dialdehydes, diol disilyl ethers, and silyl enol ethers of ketones was investigated. The method of monomer addition strongly affected the molecular weight of polymers and was optimized to yield high molecular weight polymers by model reactions. A variety of dialdehydes, diol disilyl ethers, and silyl enol ethers were polymerized in the presence of a catalytic amount of triphenylmethyl (trityl) perchlorate in CH₂Cl₂ at −78 °C according to the method of monomer addition. This polymer synthesis was unusual in that it concurrently constructed both the polyether backbone and the keto side chains from three starting compounds. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 179–188, 2000     

Comparison of connective tissue invaded by Lewis lung carcinoma to healthy connective tissue by means of micro‐Raman spectroscopy

We have measured the micro‐Raman spectra of mouse tissues invaded by Lewis lung carcinoma (LLC). We have also carried out categorical principal component analysis (CATPCA) on the acquired spectra. The results indicate that the tumor tissues can be well discriminated from normal tissues by the first two principal components extracted from the spectra. Furthermore, we have found that the concentrations of nucleic acids and lipids/fatty acids in the tumor are considerably higher than those in the normal tissue, whereas the collagen concentration is lower. These differences can be detected and characterized by Raman images using the 788 cm⁻¹ DNA/RNA band and the 1301 cm⁻¹ lipid/fatty acid band. Copyright © 2009 John Wiley & Sons, Ltd.     

Patterning of cantilevers with inverted dip-pen nanolithography: efforts toward combinatorial AFM

We report patterning of AFM cantilevers by inverted dip-pen nanolithography, thereby markedly enhancing the development of combinatorial AFM as a high-throughput force-measuring instrument capable of determining interactions between opposing libraries of biomolecules.     

Supramolecular Systems from Natural Polymers and Maleic Polyelectrolytes

Summary: The formation of polyelectrolyte complexes by interaction between chitosan and maleic acid copolymers as strong/weak dibasic polyanions was investigated. The interaction between the sodium salt of maleic acid copolymers with styrene or vinyl acetate and the chitosan hydrochloride in aqueous solution was followed by potentiometric, conductometric and turbidimetric titration. The effect of the added low molecular salt on the complex formation was also investigated. The precipitated complexes were analyzed by FTIR spectroscopy and TG analysis. Preliminary layer-by-layer deposition experiments were performed to obtain thin films.     

Synthetic mimics of antimicrobial peptides with immunomodulatory responses

A new series of aryl-based synthetic mimics of antimicrobial peptides (SMAMPs) with antimicrobial activity and selectivity have been developed via systematic tuning of the aromatic groups and charge. The addition of a pendant aromatic group improved the antimicrobial activity against Gram-negative bacteria, while the addition of charge improved the selectivity. SMAMP 4 with six charges and a naphthalene central ring demonstrated a selectivity of 200 against both Staphylococcus aureus and Escherichia coli , compared with a selectivity of 8 for the peptide MSI-78. In addition to the direct antimicrobial activity, SMAMP 4 exhibited specific immunomodulatory activities in macrophages both in the presence and in the absence of lipopolysaccharide, a TLR agonist. SMAMP 4 also induced the production of a neutrophil chemoattractant, murine KC, in mouse primary cells. This is the first nonpeptidic SMAMP demonstrating both good antimicrobial and immunomodulatory activities.     

STUDY ON LIGHTLY SULFONATED SYNDIOTACTIC POLYSTYRENE IONOMERS

Sulfonated syndiotactic polystyrene ionomers (SsPS) with 1.8 mol% degree of sulfonation have been studied.WAXD shows that the crystallinity of SsPS ionomers was decreased with increasing diameter size of the counter ions andsPS>SsPS-H>SsPS-K>SsPS-Zn. Moreover, SsPS ionomers only have a α cystal form, while original sPS has two crystalforms: α and β crystal form. TGA shows that the thermal stability of SsPS ionomers is higher than that of the original sPSand SsPS-Zn>SsPS-K>SsPS-H. DSC shows that all the glass transition temperatures (T_g) of SsPS ionomers are higherthan that of the neat sPS and SsPS-Zn>SsPS-Na>SsPS-K>SsPS-H. However, the melting temperature (T_m) andcrystallization peak temperature (T_p) of SsPS ionomers are lower and SsPS-H>SsPS-Zn>SsPS-K>SsPS-Na, while thecrystallinity (X_c) of SsPS-Zn is the lowest. Nonisothermal crystallization kinetics shows that the Avrami index of sPS andSsPS-H are both about 4, suggesting the nucleation growth of SsPS-H with lower degree of sulfonation still keeps its three-dimension form. FTIR spectra of SsPS ionomers show a splitting absorption band for asymmetric stretching vibration ofsulfonation group. The CH in-plane bending vibration of benzene ring shifted to higher wavenumber and the symmetricstretching vibration of sulfonation group changed slightly with different counter ion neutralized SsPS ionomers.     

铈对果蝇、家蚕寿命及蚕茧重量的影响

研究了不同浓度氯化亚铈对果蝇寿命,家蚕寿命及其茧重的影响,实验分两部分;（１）用不同浓度的氯化亚铈加入培养基中饲养黑腹果蝇,结果显示１３３ｍｇ／Ｌ浓度时雌果蝇,２６６ｍｇ／Ｌ浓度时雄果蝇的寿命显著延长（Ｐ〈０．０５）;（２）用不同浓度的氯化亚铈溶液浸泡桑叶,风干后分别喂养四眠期的家蚕,浓度分别为１６,３２ｍｇ／Ｌ时家蚕重量显著增加（Ｐ〈０．０５）,在４,８,１６ｍｇ／Ｌ２时家蚕寿命显著延长（Ｐ〈０