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首页> 外文期刊>Chemistry: A European journal >Urea and thiourea derivatives as low molecular-mass organogelators
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Urea and thiourea derivatives as low molecular-mass organogelators

机译：尿素和硫脲衍生物作为低分子量有机胶凝剂

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摘要

The properties of a series of organogels consisting of a urea or thiourea derivative with one or two n-alkyl substitutuents at the nitrogen atoms (a low molecular-mass organogelator (LMOG)) and an organic liquid are described. They include N.N'-dimethylurea, the LMOG of lowest molecular mass (M, 88) we are aware of. The efficiencies of the LMOGs. based the diversity of liquids gelated, the minimum amount required for gelation of a liquid at room temperature, and the temporal and thermal stabilities of the gels formed, have been investigated as a function of the number, length, and substitution pattern of their n-alkyl chains. The gels are thermally reversible and require generally very low concentrations (< 2wt%) of an LMOG. Some of the LMOGs with shorter chains are more efficient than their longer chained analogues. The structural and thermodynamic properties of the gels have been examined by IR, DSC, and X-ray diffraction techniques. Polarizing optical microscopic analyses of the gels show that the nature of gelator aggregates depends mainly on the alkyl chain length. Changes in the aggregation ability have been examined systematically by perturbing the molecular structure.
机译：描述了由在脲原子上具有一个或两个正烷基取代基的脲或硫脲衍生物组成的一系列有机凝胶（低分子质量有机凝胶剂（LMOG））和有机液体的特性。它们包括N.N'-二甲基脲，这是我们知道的最低分子量的LMOG（M，88）。改性活生物体的效率。根据凝胶化液体的多样性，已研究了室温下凝胶化所需的最小量以及所形成凝胶的时间和热稳定性，取决于其n-的数量，长度和取代方式。烷基链。该凝胶是热可逆的，并且通常需要非常低浓度（<2wt％）的LMOG。一些链较短的LMOG比链较长的类似物效率更高。凝胶的结构和热力学性质已通过IR，DSC和X射线衍射技术进行了检查。凝胶的偏振光学显微镜分析表明，胶凝剂聚集体的性质主要取决于烷基链的长度。聚集能力的变化已通过扰动分子结构进行了系统检查。

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