Supramolecular Assembly And Chiral Studies Based On Calix[4]arene/chiral Small Molecules

Chirality is one of the basic characteristics of nature.There are many forms of chiral expression,from the molecular and supramolecular level to the nano/macro level.Supramolecular chirality describes the chirality of supramolecular systems based on non-covalent interactions such as hydrogen bonding,coordination,π-π stacking,and hydrophobic interactions.It is not only related to the chirality of molecules,but also largely depends on the spatial arrangement or assembly of the constituent molecules.Although the origin of chirality in nature is still unclear,the design and application of chiral molecules and supramolecular chiral systems have attracted widespread attention in recent years.In this interesting scientific field,an important question is how to transfer the chirality of molecules to the supramolecular level.In various self-assembly systems,supramolecular gels are very attractive materials.Starting from chiral or achiral molecules,the interaction between molecules may lead to the formation of chiral aggregates in the gel.In general,gel molecules can self-assemble into aggregates of spheres,ribbons,chains or other morphologies through non-covalent bonds.When the gel molecule has chirality,these nanostructures can be given chiral characteristics.Supramolecular gel can be used as a good platform to understand the generation,transfer,amplification and functionalization of chirality in supramolecular systems.Based on the above background,this paper designed and synthesized a calix[4]arene with a modified carboxylic acid at the upper edge and a short alkyl chain at the lower edge,using a chiral small molecule as a chiral source to construct a self-assembly through non-covalent bonds.It Shows the chiral characteristics that a single molecule does not have,so as to achieve the transfer of chirality.Then the interaction between calix[4]arene and chiral small molecules with the chiral-induced structural transformation were explored deeply.It provides a theoretical basis for the construction of multifunctional chiral nanomaterials and expands its application in life sciences.This paper mainly carried out the following research work:1.Through FT-IR,1H NMR,mass spectrometry and other characterization methods,the structures of the prepared calix[4]arene compounds were characterized A series of methods were used to investigate the aggregation behavior of calix[4]arene.Rheological tests showed that the mechanical properties of the supramolecular gel formed by C-C[4]-C4/L-TA are significantly higher than that of C-C[4]-C4/D-TA under the same compounding conditions.The cryo-etched transmission electron micrograph showed that calix[4]arene and enantiomer tartaric acid formed completely different three-dimensional structures.Circular dichroism indicated that the gel induced the chiral transfer of molecules into the structure of the gel.Infrared and X-ray diffraction indicate weak interactions between molecules.Quantum chemical calculations verified the mechanism of intermolecular interactions.2.In order to better explore the assembly mechanism of supramolecular gel,the enantiomeric malic acid and calix[4]arene was introduced for compounding.It was found that the enantiomeric malic acid required a higher gel forming concentration.It showed that chirality was an important factor in the formation of supramolecular gels.The structural changes of supramolecular assemblies induced changes in chiral signals,and quantum chemistry showd how the molecular structures are stacked.3.Enantiomeric lactic acid and calix[4]arene compound was used to simulate the supramolecular assembly process of chiral drugs.Compared with the previous two chapters,the supramolecular gel formed had higher mechanical properties.Selectively induce new chiral signals.Explore the chiral transmission process of supramolecular assemblies.The circular dichroism showed that the chiral signal was selectively induced by enantiolactic acid and changed regularly with the change of complex components.The mechanism of interaction in supramolecular gel chiral transfer and the relationship between chirality signal and structural transformation of supramolecular assembly were investigated.