Characteristically steric effects of substituent on bidirectional inclusion complexation of α-substituted phenyl-2,4,6-trimethoxybenzyl(t-butyl)nitroxides with β-cyclodextrins

Using unique guest probes having more than one bulky group, we demonstrate substituent dependence on group inclusion for the molecular recognition of β-cyclodextrins (β-CDs). Group-inclusion equilibrium with 6-O-α-D-glucosyl-β-cyclodextrin (G-β-CD) having a bulky glucosyl side chain has been shown to be significantly altered as compared with unmodified β-CD. We suggest that the bulky substituents in guest and host molecules play an important role for the group inclusion of molecular recognition.