Inclusion complexes, computer imaging

X-ray crystal structures were used for the production of computer projected images of inclusion complexes of structural isomers, enantiomers and dlastereomers with a- or B-cyclodextrin. These projections allow for a visual evaluation of the interaction that occurs between various molecules and cyclodextrin, and an understanding of the mechanism for chromatographic resolution of these agents with bonded phase chromatography. 

Although it is well understood that molecules must be able to enter the cavity of the cyclodextrin molecule for complexation to occur, and therefore, under chromatographic conditions, for retention to result, the differential binding of two stereoisomers within the cyclodextrin that allows for their differential retention is not always apparent. An understanding of this can be obtained through the use of three dimensional computer graphic imaging of the crystal structure of the inclusion complex. 

ARMSTRONG Computer Imaging of Cyclodextrin Inclusion Complexes... 

Figure 2. Computer imaging of crystal structures of the inclusion complexes of para (A), meta (B) and ortho (C) nitrophenol with a-cyclodextrin. The complex is shown with van der Waal s radii, and the front section of the complex cut away in order to expose the nitrophenol molecule.

Figure 3. Computer imaging of the inclusion complexes of d- A) and 1-(B) propranolol with B-cyclodextrin. The chemical structures are illustrated with van der Waals radii shown for only the secondary amine of propranolol and the 2- and 3- hydroxyl groups of the B-cyclodextrin.

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