Aggregation of tetrakis(p-sulfonatophenyl)porphyrin within modified mesoporous MCM-41

We report the formation of monomeric and aggregated tetrakis(p-sulfonatophe nyl)porphyrin encapsulated within an aluminosilicate mesostructure, specifi cally MCM-41, under different pH conditions. It was necessary to stabilize the synthesized MCM-41 through use of a silylation reagent, (aminopropyl)tr iethoxysilane, which cross-links oxygen on the surface (thus rigidifying th e walls of the mesoporous material) and functionalizes the interface for pr oper guest-host interaction. XRD, UV-vis absorption, and fluorescence measu rements are used as spectroscopic tools to characterize the various product s.