Dynamic hemicarcerands and hemicarceplexes

[GRAPHICS] The reversible nature of the imine bond formation in CDCl3 solution has been exploited to exchange substituted for unsubstituted m-phenylenediamine (MPD) units in hemicarcerand octaimines. Moreover, acid-catalyzed imine exchange has been shown to provide a novel mechanism whereby ferrocene (Fc) can be released as an entrapped guest from the hemicarceplex C(2)B(4)circle dot Fc dissolved in CDCl3 to give the hemicarcerand C2B4 when excess of both MPD and trifluoroacetic acid are present.