Porwal Vishal K, André Erwan, Carof Antoine, Bastida Pascual Adolfo, Carteret Cédric, Ingrosso Francesca
Laboratoire de Physique et Chimie Théoriques UMR 7019, Université de Lorraine and CNRS, F-54000 Nancy, France.
Laboratoire de Chimie Physique et Microbiologie pour les Matériaux et l'Environnement UMR 7564, Université de Lorraine and CNRS, F-54000 Nancy, France.
Molecules. 2024 Apr 18;29(8):1853. doi: 10.3390/molecules29081853.
Layered double hydroxides (LDHs) are fascinating clay-like materials that display versatile properties, making them an extremely fertile playground for diverse applications, ranging from bio-compatible materials to the pharmaceutical industry to catalysis and photocatalysis. When intercalating organic and bio-organic species between the inorganic layers, such materials are named hybrid LDHs. The structure-property relation in these systems is particularly relevant, since most of the properties of the materials may be fine-tuned if a comprehensive understanding of the microscopic structure in the interlamellar space is achieved, especially with respect to the reorganization under water uptake (swelling). In this work, we combined experiments and simulations to rationalize the behavior of LDHs intercalating three carboxylates, the general structure of which can be given as [Mg4Al2(OH)12]A2-·XH2O (with A2- = succinate, aspartate, or glutamate and X representing increasing water content). Following this strategy, we were able to provide an interpretation of the different shapes observed for the experimental water adsorption isotherms and for the evolution of the infrared carboxylate band of the anions. Apart from small differences, due to the different reorganization of the conformational space under confinement, the behavior of the two amino acids is very similar. However, such behavior is quite different in the case of succinate. We were able to describe the different response of the anions, which has a significant impact on the isotherm and on the size of the interlamellar region, in terms of a different interaction mechanism with the inorganic layer.
层状双氢氧化物（LDHs）是一类引人注目的类粘土材料，具有多种特性，使其成为从生物相容性材料到制药行业再到催化和光催化等各种应用的极其肥沃的试验场。当在无机层之间插入有机和生物有机物种时，这类材料被称为杂化LDHs。这些体系中的结构-性能关系尤为重要，因为如果能够全面了解层间空间的微观结构，特别是关于吸水（膨胀）时的重组情况，那么材料的大多数性能都可以进行微调。在这项工作中，我们结合实验和模拟来阐明插入三种羧酸盐的LDHs的行为，其一般结构可表示为[Mg4Al2(OH)12]A2-·XH2O（其中A2- = 琥珀酸盐、天冬氨酸盐或谷氨酸盐，X代表不断增加的水含量）。按照这一策略，我们能够对实验测得的水吸附等温线的不同形状以及阴离子红外羧酸盐带的演变作出解释。除了由于受限构象空间的不同重组而产生的微小差异外，这两种氨基酸的行为非常相似。然而，琥珀酸盐的情况则有很大不同。我们能够根据与无机层不同的相互作用机制来描述阴离子的不同响应，这种响应会对等温线以及层间区域的大小产生重大影响。
