ASSOCIATION MODES OF A 1-1 INCLUSION COMPOUND OF BETA-CYCLODEXTRIN WITH 1-CYANONAPHTHALENE IN AQUEOUS-SOLUTIONS - SELF-ASSOCIATION, ASSOCIATION WITH ALCOHOLS, AND ASSOCIATION WITH A 1-1 BETA-CYCLODEXTRIN ANISOLE INCLUSION COMPOUND

A 1:1 inclusion compound (NC) of β-cyclodextrin (CDx) with 1-cyanonaphthalene (N) has been found to exhibit three types of association modes. One of these is the self-association of NC. An association species (NC·NC) composed of two NCs shows an N excimer fluorescence. Another mode is the association of NC with alcohol to form a 1:1:1 inclusion compound. The last one is the association of NC with a 1:1 inclusion compound (AC) formed between CDx and anisole. For a CDx-anisole-N inclusion compound (NC·AC), the fluorescence from an exciplex formed between N and anisole has been observed. Equilibrium constants for the formation of these inclusion compounds have been determined. The finding that a rate constant for fluorescence quenching of the 1:1:1 inclusion compound including alcohol by I- is about half those of NC, the excimer (NC·NC), and the exciplex (NC·AC) indicates that one open mouth of the CDx cavity is thoroughly capped (floored) with alcohol in the 1:1:1 inclusion compound. No fluorescence quenching by IO3- has been observed for NC·NC, NC·AC, and the 1:1:1 inclusion compound including alcohol. © 1990 American Chemical Society.