Spectral and photophysical studies of the 1 : 3 (guest/host) rotaxane-like inclusion complex formed by a 3H-indole and beta-cyclodextrin

In the present paper, we report a new type of rotaxane-like inclusion complex, i.e., the 1:3 (guest/host) type formed by iodotrimethyl 2-(p-hexylaminopheny1)-3,3-dimethyl- 5-carboethoxy-3H-indole ammonium (I), a fluorescent cationic surfactant, and beta-cyclodextrin (beta-CD). The time-resolved fluorescence measurement reveals that only two species of 1 exist within the whole range of beta-CD concentrations. Both the steady-state and the time-resolved fluorescence results show that the stoichiometry of the inclusion complex is 1:3. The urea effect on the formation of the inclusion complex has been investigated. It was found that the 1:3 inclusion complex is still formed in the presence of 3 M urea, while the association constant is markedly reduced. This suggests the hydrophobic nature of the interaction of 1 with either beta-CD or urea.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000072621900006&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Chemistry, PhysicalSCI(E)42ARTICLE111877-188310