The crystal structure of the inclusion complex of cyclomaltoheptaose (β-cyclodextrin) with 3,5-dimethylbenzoic acid

Abstract

The crystal of theβCD-3,5-dimethylbenzoic acid inclusion complex is triclinicP1 witha=15.707(3),b=15.694(3),c=15.999(3) Å, α=101.502(5),β=101.557(5), γ=103.805(4)°,V=3624 ų, andZ=1. Two crystallographically independentβCD molecules form a dimer by means of hydrogen bonds between secondary hydroxyl groups in which disordered guest molecules in six orientations are accommodated. In two of them the guest molecules are situated at the dimer interface, their carboxyl groups interacting with the carboxyl groups of two other guest orientations that are found on either side of the monomer cavity. In the two last orientations the guest molecules enter the monomer cavities in an opposite sense with the carboxyl groups protruding from the primary side and are stabilized by cyclodextrin hydroxyl groups. A dense water network is formed in the interdimer space consisted of 18.2 water molecules distributed over 24 sites.