Fluorescence Properties, Induced-Fit Guest Binding and Molecular Recognition Abilities of Modified γ-Cyclodextrins Bearing Two Pyrene Moieties

• Published in: Bulletin of the Chemical Society of Japan 2001-01, Vol.74 (1), p.157-164
• Main Authors: Aoyagi, Taiyo, Ikeda, Hiroshi, Ueno, Akihiko
• Format: Article
• Language: English
• ISSN: 0009-2673; 1348-0634
• DOI: 10.1246/bcsj.74.157

γ-Cyclodextrin (γ-CD) derivatives bearing two pyrene moieties at AB, AC, AD, and AE glucose units (1–4), were prepared as chemosensors for detecting molecules by their guest-responsive excimer emission intensity. All these hosts exhibited predominant excimer emission and remarkable induced circular dichroism (ICD) in a 20% dimethyl sulfoxide aqueous solution. The excimer emission and the ICD intensities mostly decreased upon addition of a variety of organic guests. The result indicates that 1–4 undergo an induced fit conformational change upon complex formation, excluding the pyrene moieties from inside to outside the γ-CD cavity in guest binding. The guest-induced fluorescence variations were analyzed by 1 : 1 host–guest stoichiometry and the obtained binding constants were roughly correlated with the guest-induced fluorescence variations. The binding and fluorescence data revealed that 1–4 have remarkable molecular recognition abilities for bile acids and other guests.