Construction and Control of Helical Supramolecules Based on Sequential Information of Carbon-Chains

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We have been studying on inclusion compounds of steroids over ten years. In this research project we aim to construct and control helical supramolecules in inclusion crystals on the basis of sequential information of chiral carbon-chains. Such a study may enable us to establish the concept of molecular information and expression of chiral carbon-chain compounds, such as steroids. The results are summarized as follows ;1. We synthesized many steroidal derivatives involving sequential information, starting from commercially availabe cholic and deoxycholic acids. Such compounds were found to form inclusion crystals composed of helical assemblies in most of the cases.2. The inclusion behaviors of the steroidal hosts were checked by using more than one hundred guests. We determined a scope of the guest components included. The scope for each host varied from one case to another. We accumulated inclusion data necessary for considering possible mechanism of the host-guest complexation from a viewpoint in size, shape, chirality and polarity.3. We analyzed the resulting inclusion compounds by means of powder and single crystal X-ray crystallography, leading to the finding of over fifty helical structures of the inclusion compounds. We analyzed the helical assemblies from various aspects of the helical structures by using various softwares. For example, molecular graphics study helped us to evaluate a relation between the original molecular structures and the resulting helical structures.4. We confirmed that multiple combinations among the hydrogen-bonding groups may play an important role in determining the helical structures. Now we believe that chiral carbon-chain compounds tend to construct comprehensive helical assemblies on the basis of diversible hydrogen bonds and van der Waals interaction due to facially amphiphilicity.