Aggregation and exciton emission of a cyanine dye encapsulated within mesoporous MCM-41

We report the formation of monomeric and J-aggregated 1,1 ' ,3,3 ' -tetraet hyl-5,5 ' ,6,6 ' -tetrachlorobenzimidazolocarbocyanine (referred to as TTBC ) encapsulated within an aluminosilicate mesostructure, specifically MCM-41 , under different pH conditions. It was necessary to stabilize the synthesi zed MCM-41 through use of a silylation reagent, (aminopropyl)triethoxysilan e, which cross-links oxygen on the surface (thus thickening the walls of th e mesoporous material) and functionalizes the interface for proper guest-ho st interaction. XRD, UV-vis absorption and fluorescence measurements are us ed as spectroscopic tools to characterize the various products. The composi te consisting of J-aggregated TTBC and the aluminosilicate represents a new fluorescent nanomaterial that possesses the properties of the aggregate, y et avoids the essentially unfettered topography and physical length accompa nying the formation of an aggregate in solution or adsorbed onto an interfa ce.