Gelation or molecular recognition; is the bis-(α,β-dihydroxy ester)s motif an omnigelator?
Gelation or molecular recognition; is the bis-(α,β-dihydroxy ester)s motif an omnigelator?
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DOI：
10.3762/bjoc.6.123
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发表时间：
2010-11-18
影响因子：
2.7
通讯作者：
Paul A
中科院分区：
文献类型：
--
作者：
Griffiths PC;Knight DW;Morgan IR;Ford A;Brown J;Davies B;Heenan RK;King SM;Dalgliesh RM;Tomkinson J;Prescott S;Schweins R;Paul A
了解低分子量溶质在低浓度下对液体的凝胶化，可以深入了解许多分子识别现象，并提供了一种简单的方法来改变液体的物理性质。双-（α，β-二羟基酯）在这里显示出热可逆地凝胶化广泛的溶剂，提出了有趣的问题，凝胶化的机制。在5-50 mg ml-1的胶凝剂浓度下，在丙酮、乙醇/水混合物、甲苯、环己烷和氯仿（后者，尽管胶凝剂浓度较高）中成功地形成凝胶。一系列的中子技术-特别是小角中子散射（SANS）-已被用来探测这些凝胶的选择的结构。凝胶化在一系列溶剂类型中的普遍性表明凝胶化机制是双-（α，β-二羟基酯）基序的特征，SANS证明在30-40 μ m范围内存在规则结构。所形成的结构的明显棒状特征与溶剂的极性之间的相关性是明显的。初步的自旋回波中子散射研究（SESANS）表明，没有任何更大规模的结构。非弹性中子能谱（INS）的研究表明，溶剂在很大程度上不受凝胶化的影响，但揭示了样品的热历史的见解。这类中子的进一步研究（特别是SESANS和INS）是有必要的，希望这项工作将激励其他人从事这方面的研究。
Understanding the gelation of liquids by low molecular weight solutes at low concentrations gives an insight into many molecular recognition phenomena and also offers a simple route to modifying the physical properties of the liquid. Bis-(α,β-dihydroxy ester)s are shown here to gel thermoreversibly a wide range of solvents, raising interesting questions as to the mechanism of gelation. At gelator concentrations of 5–50 mg ml−1, gels were successfully formed in acetone, ethanol/water mixtures, toluene, cyclohexane and chloroform (the latter, albeit at a higher gelator concentration). A range of neutron techniques – in particular small-angle neutron scattering (SANS) – have been employed to probe the structure of a selection of these gels. The universality of gelation in a range of solvent types suggests the gelation mechanism is a feature of the bis-(α,β-dihydroxy ester) motif, with SANS demonstrating the presence of regular structures in the 30–40 Å range. A correlation between the apparent rodlike character of the structures formed and the polarity of the solvent is evident. Preliminary spin-echo neutron scattering studies (SESANS) indicated the absence of any larger scale structures. Inelastic neutron spectroscopy (INS) studies demonstrated that the solvent is largely unaffected by gelation, but does reveal insights into the thermal history of the samples. Further neutron studies of this kind (particularly SESANS and INS) are warranted, and it is hoped that this work will stimulate others to pursue this line of research.
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影响因子：
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