Abstract
Crystal structures of heptakis (2,6-di-O-methyl)-β-cyclodextrin (dimethyl-β-CDx) complexes with p-iodophenol and p-nitrophenol were determined by the X-ray method. The dimethy1-β-CDx molecule is in the round shape, which is maintained by the intramolecular hydrogen bonds formed between adjacent 2,6-di-O-methylglucose residues. The guest molecules in both complexes are not included within the host cavity, but located in intermolecular spaces between dimethyl-β-CDx molecules. The host cavity includes three water molecules and a methoxyl group of adjacent dimethyl-β-CDx.