Formation of Superstructure Composed of Modified Cyclodextrins as Molecular “Blocks” in Aqueous Solution with Host-Guest Complexation. Correlation of Chemical Structure of Modified Group with Complexation

Abstract

ABSTRACT:N'-tert-Butoxycarbonylmonoamino acid-binding ,8-CDs (1,2,3,4,5) and a-CD (6) were prepared by DCC coupling. NMR study suggests some of these novel modified CDs that act as host and guest to prefer "pseudo polymer" formation. The length of an arm between the N'-tert-butoxycarbonyl group and C6 position on the glucose ring was that of -NH-Ca -CO-NH-. Modified ,8-CDs having longer arm form intramolecular rather than intermolecular complexes.

Polymeric Rotaxanes

“…These classes depend on the combination of CDs and included guest molecules. When a guest group is attached to a host molecule, the conjugate might form intramolecular complexes [650][651][652][653][654][655][656][657][658][659] or intermolecular complexes 50,637,[660][661][662][663][664][665][666][667][668][669][670][671][672][673][674][675][676][677] to give a supramolecular polymer (polypseudo [2]rotaxane) depending on the flexibility and the length of the guest part. This section focuses on a daisy chain constructed by monosubstituted CD derivatives in crystal structures.…”

Characterization and structural determination of 3A-amino-3A-deoxy-(2AS, 3AS)-cyclodextrins by NMR spectroscopy

“…In order to add flexibility, we prepared several CyDs containing a hydrophobic substituent on a primary hydroxyl site, C6 site. [8][9][10][11][12][13] A phenyl group in these modified CyDs, known as the 'self-guest group,' helps to control the cavity size. The modified CyDs also contain a flexible arm composed of sp 3 carbons between the CyD cavity and phenyl group.…”

“…Monosubstituted CyDs lack the symmetry of free CyDs and have a distorted cavity with ring-current effect from the aromatic group of 'self-guest group' that create a magnetically inhomogeneous environment 8 The distorted environment is clear from NMR studies of these CyD derivatives. 8,[10][11][12][13] Many guest-modified CyDs with additions to the primary hydroxyl site have been reported; however, very few studies that modify secondary hydroxyl site have been reported. We have studied 3A-amino-3A-deoxy-(2AS,3AS)-CyD, a CyD in which the amino-substituted glucose residue was replaced by an altro-pyranose unit with axial hydroxyl groups as the starting material.…”