title: Supramolecular tilt chirality in crystals of steroids and alkaloids.
abstract: The concept of supramolecular chirality has assumed increasing importance in association with the development of supramolecular chemistry over the last two decades. In chiral crystals, 2 1 helical molecular assemblies are frequently observed as key motifs. Helical handedness of the 2 1 assemblies, however, has not been determined from the mathematical or crystallographical viewpoints. In this context, we have proposed two new concepts, three-axial chirality and tilt chirality. On the basis of the concepts, we describe supramolecular chirality and determine the handedness of 2 1 assemblies that are composed of relatively complicated molecules with multiple stereogenic centers such as brucine, bile acids, and cinchona alkaloids as well as those of simple molecules.
authors.affiliation: Department of Material and Life Science, Graduate School of Engineering, Osaka University, Suita, Osaka, Japan. hisaki@mls.eng.osaka-u.ac.jp
authors.forename: Ichiro
authors.initials: I
authors.lastname: Hisaki
authors.forename: Norimitsu
authors.initials: N
authors.lastname: Tohnai
authors.forename: Mikiji
authors.initials: M
authors.lastname: Miyata
mesh_terms: D000470:Alkaloids / Q000737:chemistry*; D001647:Bile Acids and Salts / Q000737:chemistry; D002930:Cinchona Alkaloids / Q000737:chemistry; D003460:Crystallization; D046911:Macromolecular Substances / Q000737:chemistry; D008958:Models, Molecular; D013237:Stereoisomerism; D013256:Steroids / Q000737:chemistry*; D013331:Strychnine / Q000031:analogs & derivatives / Q000737:chemistry
chemical_list: D000470:Alkaloids; D001647:Bile Acids and Salts; D002930:Cinchona Alkaloids; D046911:Macromolecular Substances; D013256:Steroids; C083806:brucine; D013331:Strychnine