Novel refreshable N‐halamine polymeric biocides containing imidazolidin‐4‐one derivatives

A novel cyclic‐amine monomer, 1‐acryloyl‐2,2,5,5‐tetramethylimidazolidin‐4‐one (ACTMIO), was synthesized in a good yield through the reaction of acryloyl chloride with 2,2,5,5‐tetramethylimidazolidin‐4‐one and was fully characterized with Fourier transform infrared and ¹H NMR studies. ACTMIO was copolymerized with several widely used acrylic and vinyl monomers under ordinary conditions. In the presence of triallyl‐1,3,5‐triazine‐2,4,6(1H,3H,5H)‐trione, ACTMIO was easily grafted onto most textile fabrics. After regular chlorine bleach treatment, N‐halamine derivatives of the corresponding polymeric materials exhibited antibacterial properties against Escherichia coli, and these properties were durable and refreshable with chlorine bleaching. The relationship between the structures and antibacterial properties of the samples is further discussed. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3073–3084, 2001     

Comparative Study on Decomposition of CFCl<Subscript>3</Subscript> in Thermal and Cold Plasma

Decomposition of CFCl₃ was investigated in an RF inductively coupled thermal reactor in neutral, oxidative and reductive conditions, and in a silent electric discharge (cold plasma) in neutral and oxidative conditions, respectively. In RF thermal plasma reactor, in neutral conditions, mainly gaseous products and minor amount of solid soot was formed. About 50% the soot could be extracted by toluene. Both the gas phase and the extract contained a wide range of aliphatic and aromatic compounds including chlorine and fluorine containing polyaromatic hydrocarbons (PAHs). In oxidative conditions much less soot was formed as compared to the neutral case. The solid product contained about 45% extractable fraction even in oxidative conditions. However, the extract contained less PAHs than in neutral conditions. In reducing atmosphere the soot yield was similar to the neutral case, but the soot contained 29% extractable fraction only. The extract consisted of polyhalogenated aromatic and polyaromatic hydrocarbons as main components. In neutral conditions different chlorofluorocarbons (CFCs) and chlorine were detected as gaseous products in cold plasma. In oxidative conditions, as final products of decomposition CO₂, CFCs and Cl₃ were formed.     

Improved analysis of volatile halogenated hydrocarbons in water by purge-and-trap with gas chromatography and mass spectrometric detection

An analytical system composed of a purge-and-trap injection system coupled to gas chromatography with mass spectrometric detection (PTI-GC-MS) specific for the analysis of volatile chlorinated hydrocarbons (VCHCs) (chloroform; 1,1,1-trichloroethane; tetrachloromethane; 1,1,2-trichloroethylene; tetrachloroethylene) and trihalomethanes (THMs) (chloroform; bromodichloromethane; dibromochloromethane; bromoform) in water was optimised. Samples were purged and trapped in a cold trap (-100 degrees C) fed with liquid nitrogen (cryo-concentration). In order to make this method suitable also for only slightly contaminated waters, some modifications were made to PTI sample introduction, in order to avoid any air intake into the system. PTI, GC and MS conditions were optimised for halogenated compound analysis and limits of detection (LOD) were evaluated. The proposed method allows analysis of samples whose concentrations range from microg/L to ng/L. It is, therefore, applicable to drinking waters, in analyses required by law, and to slightly contaminated aqueous matrices, such as those found in remote areas, in environmental monitoring. Moreover, by changing cold trap temperature, even sparkling mineral waters can be analysed, thus avoiding CO2 interference during the cryo-concentration phase. Our method has been successfully used on real samples: tap water, mineral water and Antarctic snow.     

The potential of achiral sponge-derived and synthetic bromoindoles as selective cytotoxins against PANC-1 tumor cells

Our quest to isolate and characterize natural products with in vitro solid tumor selectivity is driven by access to repositories of Indo-Pacific sponge extracts. In this project an extract of a species of Haplosclerida sponge obtained from the US NCI Natural Products Repository displayed, by in vitro disk diffusion assay (DDA) and IC₅₀ determinations, selective cytotoxicity with modest potency to a human pancreatic cancer cell line (PANC-1) relative to the human lymphoblast leukemia cell line (CCRF-CEM). Two brominated indoles, the known 6-bromo conicamin (1) and the new derivative, 6-Br-8-keto-conicamin A (2), were identified and 2 (IC₅₀ 1.5 μM for the natural product vs 4.1 μM for the synthetic material) was determined to be responsible for the cytotoxic activity of the extract against the PANC-1 tumor cell line. The new natural product and ten additional analogs were prepared for further SAR testing.     

Inter- and Intramolecular Aryl–Aryl Interactions in Partially Fluorinated Ethylenedioxy-bridged Bisarenes**

Several ethylenedioxy-bridged bisarenes with a variety of type and number of aryl groups were synthesized to study non-covalent dispersion-driven inter- and intramolecular aryl–aryl interactions in the solid state and gas phase. Intramolecular interactions are preferably found in the gas phase. DFT calculations with and without dispersion correction show larger interacting aromatic groups increase the stabilization energy of folded conformers and decrease the intermolecular centroid–centroid distance. Single-molecule structures generally adopt folded conformations with short intramolecular aryl–aryl contacts. Gas electron diffraction experiments were performed exemplarily for 1-(pentafluorophenoxy)-2-(phenoxy)ethane. A new procedure for structure refinement was developed to deal with the conformational complexity of such molecules. The results are an experimental confirmation of the existence of folded conformations of this molecule with short intramolecular aryl–aryl distances in the gas phase. Solid-state structures are dominated by stretched structures without intramolecular aryl–aryl interactions but interactions with neighboring molecules.     

Conducting Organic Frameworks Based on a Main‐Group Metal and Organocyanide Radicals

Reactions of the main‐group cation Tl^I with anions of 2,5‐derivatives of TCNQ (TCNQ=7,7,8,8‐tetracyanoquinodimethane) have led to the isolation of a family of unprecedented semiconducting main‐group‐metal–organic frameworks, namely, [Tl(TCNQX₂)], (X=H, Cl, Br, I). A comparison of single‐crystal and powder X‐ray diffraction data revealed the existence of a third polymorph of the previously reported material Tl(TCNQ)] and two distinct polymorphs of [Tl(TCNQCl₂)], whereas only one phase was identified for [Tl(TCNQBr₂)] and [Tl(TCNQI₂)]. These new results are described in the context of the structures of other known binary metal–TCNQ frameworks that display a variety of coordination environments for the central cation, namely, four‐, six‐, and eight‐coordinate, and different arrangements of the adjacent TCNQ radicals—parallel versus perpendicular—in the stacked columns. The halogen substituents affect the structures and the properties of these compounds, owing to both steric and electronic effects as evidenced by the semiconducting properties of crystals of [Tl(TCNQCl₂)] phase I, [Tl(TCNQBr₂)], and [Tl(TCNQI₂)], which correlate well with the distances of adjacent TCNQ radicals in the columns. 1D infinite Hückel model simulations of the band structures of [Tl(TCNQCl₂)] phase I, [Tl(TCNQBr₂)], and [Tl(TCNQI₂)] were conducted with and without consideration of the Tl^I cations, the results of which indicate that the charge mobility does not strictly occur in one dimension. The modulations of the band structures with various assumptions of the energy difference (Δ) between the Tl^I 6s orbital and the TCNQ LUMO orbital were calculated and are discussed in light of the observed properties.     

Synthesis and Fungicidal Activity of Thiazoline Derivatives Containing Halogenated Indolyl Moiety

Abstract

A series of novel 1,3-thiazoline derivatives containing a 5- or 6-position halogenated indole moiety were synthesized via a one-pot and three-step reaction. Their structures were confirmed by spectroscopic methods. The fungicidal activities of all the title compounds were evaluated. Most of them exhibited moderate to high activity against eight plant pathogens at the concentration of 50 ug/mL. Generally the fungicidal activity of fluorinated indolyl thiazolines was higher than that of chlorinated indolyl thiazoline derivatives.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.

GRAPHICAL ABSTRACT      

一种基于离子迁移谱的气相色谱检测器及其应用

离子迁移谱作为气相色谱的检测器,兼有色谱的高分离能力和离子迁移谱的高灵敏度,有利于实现复杂混合物的实时在线监测。基于在色谱、离子迁移谱方面的研究基础,本实验室搭建了一套以离子迁移谱为检测器的气相色谱仪,分别对检测器的温度、总电压、尾吹气流速等参数进行了系统优化,并用于碘甲烷、1,2-二氯乙烷、四氯化碳和二溴甲烷4种卤代烃化合物的检测。实验结果表明,参数优化后的离子迁移谱检测器对碘甲烷、1,2-二氯乙烷、四氯化碳和二溴甲烷的检出限可分别达到2、0.02、1和0.1 ng,线性范围有两个数量级。离子迁移谱与气相色谱联用,其二维的分离能力可以为复杂混合物的准确定性提供更多的信息,还可以实现不同化合物的选择性检测。