Multi-component interaction between bisstyryl dyes and cucurbit[7]uril

In this paper, we report the interaction of the cucurbit[7]uril (CB[7]) molecular container with bisstyryl dyes, (E)-1,1′-(propane-1,3-diyl)bis(4-(4-methoxystyryl)pyridinium) bromide (1) and (E)-1,1′-(propane-1,3-diyl)bis(4-(4-(dimethylamino)styryl)pyridinium) bromide (2), which differ from each other by presence of OCH3 (dye 1) or N(CH3)2 (dye 2) substituents in phenyl ring. The interaction of bisstyryl dyes with CB[7] results in the formation of different multicomponents complexes with composition (1)2@CB[7] and 1@(CB[7])2 and 2@CB[7] and 2@(CB[7])3. Complex formation was confirmed by a combination of optical, NMR and electrospray ionization mass spectroscopy (ESI-MS) methods. The composition of the formed complexes depends on the relative stoichiometry of dye and CB[7]. Complex formation is accompanied by substantial changes in the optical characteristics of the dyes and formation of excimer species.