Synthesis and Adsorption Property of Two Polymeric Adsorbents with Pendent Ether Bonds

Two polymeric adsorbents, poly(methyl p-vinylbenzvl ether) and oolv(ohenvl p-vinylbenzyl ether), were synthesized from chloromethylated polystyrene, Their adsorptionproperty for phenol in hexane solution was investigated. The results showed that the twoadsorbents adsorb phenol from hexane solution through hydrogen-bonding and π-π stacking interaction.     

Synthesis and Characterization of Novel Polyimides Based on Pyridine-containing Diamine

A new aromatic diamine monomer containing pyridine unit, 2,6-bis （4-aminophenoxy- 4＇-benzoyl）pyridine（BABP）, was synthesized in three steps, starting from 2,6-pyridinedicarboxyl chloride. A series of novel pyridine-containing polyimides were prepared v/a the polycondensation of BABP with various aromatic dianhydrides through poly（amic acid） precursors, and thermal or chemical imidization of the precursors. The polyimides exhibit desirable properties, e.g., good solubility in N-methyl-2-pyrrolidone and m-cresol, excellent thermal stability and film-forming capability, as well as high inherent viscosity, indicating high molecular weight.     

Mixed-valent diruthenium diphosphonate with kagomé structure

This paper reports the first example of diruthenium phosphonate with kagomé structure, namely, [NH3(CH2)4NH3][Ru2(hedpH(0.5))2].2H2O (hedp = 1-hydroxyethylidenediphosphonate). The compound contains kagomé layers that are linked by very strong hydrogen bonds into a nanoscale kagomé structure. Ferromagnetic interactions are mediated between the paramagnetic diruthenium units.     

4—氟—3—羟基—1—取代苯基—6—哒嗪酮类结构及其反应的研究

氟代马来酐和苯肼缩合,反应先在乙醚后在25％盐酸中进行。4-氟-3-羟基-1-苯基-6-哒嗪酮(Ⅰ)的收率达54％,文献仅26％。Ⅰ和吗啡啉反应,得熔点为243～244℃的白色晶体。熔点及元素分析结果(表1)表明,产物为4-吗啡啉基-3-羟基-1-苯基-6-哒嗪酮(Ⅱ),据此作者认为氟原子位于第4位。     

New ent‐Abietanoids from Isodon rubescens

Six new ent‐abietane diterpenoids, rubescensins I–M ( 1 – 5 ) and P ( 6 ), along with two related acetonide derivatives ( 7 and 8 ), were isolated from Isodon rubescens. Their structures were elucidated by detailed spectroscopic analysis. Compound 5 is the first N‐containing diterpenoid from the genus Isodon, exhibiting notable cytotoxicity against human tumor K562 cells.     

Synthesis of fused bicyclic pyridines with microwave-assisted intramolecular hetero-Diels-Alder cycloaddition of acetylenic pyrimidines

A series of acetylenic pyrimidines was synthesized and subjected to microwave irradiation. In contrast to conventional heating, the microwave irradiations generally gave clean conversion to fused bicyclic pyridines for all substrates reported with shorter reaction time. This method has been successfully applied to the synthesis of both fused lactones and lactams.     

影响苯胺电化学计量聚合因素的探讨

本文对影响苯胺电化学计量聚合的因素进行了探讨，这些因素包括：电化学聚合方法、电极电位（Ｅ）、电流密度（Ｉ），以及苯胺单体和酸溶液的浓度等，实验结果表明，最合适的聚合方法为恒电流法，其条件为：电极电位不大于０．７０Ｖ（ｖｓ．ＳＣＥ）聚合电流密度（Ｉ）约为０．０５ｍＡ／ｃｍ＾２，苯胺单体浓度为１．１ｍｏｌ／Ｌ，酸（ＨＣｌ）的浓度则为２．２ｍｏｌ／Ｌ     

多相催化反应原位红外系统及其应用

设计和建立了一套能耐高温的用于多相催化反应研究的原位红外系统，反应温度从室温到１１５０Ｋ，系统真空为１．０＊１０＾５－１．０－１０＾－４Ｐａ，红外光谱检测范围为４８００－２００ｃｍ＾－１。此系统扩展了原仪器的功能，提高了仪器利用率和效率。     

On the Criteria of Instability for Electrochemical Systems

Both cyclic-voltammetry-based and impedance-based experimental criteria that have been developed recently for the oscillatory electrochemical systems are critically appraised with two typical categories of oscillators.Consistent conclusions can be drawn by the two criteria for the category of oscillators that involve the coupling of charge transfer mainly with surface steps(e.g.ad-and desorption)such as in the electrooxidation of C1 organic molecules.Whereas,impedance-based criterion is not applicable to the category of oscillators that involve the coupling of charge transfer mainly with mass transfer(e.g.diffusion and convection) such as in the Fe(CN)6^3- reduction accompanying periodic hydrogen evolution.The reason is that the negative impedance cannot include the feedback information of convection mass transfer induced by the hydrogen evolution.However,both positive and negative nonlinear feedbacks,i.e., the diffusion-limited depletion and convection-enhanced replenishment of the Fe(CN)6^3- surface concentration,that coexist between the bistability,i.e.,Fe(CN)6^3- reduction with and without hydrogen evolution at lower and higher potential sides respectively,are all reflected in the crossed cyclic voltammogram(CCV).It can be concluded that the voltammetry-based criterion(in time domain)is more intuitive,less time-consuming and has a wider range of applications than the impedancebased one (in frequency domain).     

Slow internal dynamics in proteins: application of NMR relaxation dispersion spectroscopy to methyl groups in a cavity mutant of T4 lysozyme

Recently developed carbon transverse relaxation dispersion experiments (Skrynnikov, N. R.; et al. J. Am. Chem. Soc. 2001, 123, 4556-4566) were applied to the study of millisecond to microsecond time scale motions in a cavity mutant of T4 lysozyme (L99A) using methyl groups as probes of dynamics. Protein expressed in E. coli cells with (13)CH(3)-pyruvate as the sole carbon source contained high levels of (13)C enrichment at a total of 80 Val gamma, Leu delta, Ile gamma (2), Ala beta, and Met epsilon methyl positions with little extraneous incorporation. Data for 72 methyl groups were available for analysis. Dispersion profiles with large amplitudes were measured for many of these residues and were well fit to a two-state exchange model. The interconversion rates and populations of the states, obtained from fitting relaxation dispersion profiles of each individual probe, were remarkably homogeneous and data for nearly all methyl groups in the protein could be collectively fit to a single cooperative conformational transition. The present study demonstrates the general applicability of methyl relaxation dispersion measurements for the investigation of millisecond time scale protein motions at a large number of side-chain positions. Potential artifacts associated with the experiments are described and methods to minimize their effects presented. These experiments should be particularly well suited for probing dynamics in high molecular weight systems due to the favorable NMR spectroscopic properties of methyl groups.