Disrupting aggregation of tethered rhodamine B dyads through inclusion in cucurbit[7]uril.

Hexano- and dodecano-tethered diesters of rhodamine B were prepared. The absorption and fluorescence spectra of these flexibly tethered dyads were compared with those of the rhodamine 3B ethyl ester. Increased J- and H-type dimer formation and decreased fluorescence emission were observed for the tethered dyads. Complexation of the cationic chromophoric units in cucurbit[7]uril (CB7) hosts decreased H-dimer aggregation, especially for the dodecano-tethered dyad. The monomeric dye and both dye dyads exhibited enhanced fluorescence upon addition of CB7.