Photoinduced electron transfer and surface plasmon resonance in materials consisting of pyrene fluorophore and Au nanorods immobilized on MCM-48 surface

Mesoporous silica of the MCM-48 type as a support for fluorophore molecules was functionalized with 3-aminopropyl and 3-thiolopropyl groups. Then, molecules consisting of a fluorophore pyrene group and receptor fragments with donor N and O atoms were covalently attached by grafting of carboxyl groups to amino groups on a mesoporous silica surface. Additionally, Au nanorods were attached to thiol groups on the same surface. The vicinity of Au nanorods in a material with pyrene derivatives covalently grafted on the functionalized MCM-48 silica enhanced fluorescence of the composite material due to the surface plasmon resonance effect. The fluorescence emission of the prepared recognition material is quenched specifically owing to the photoinduced electron transfer effect after coordination reactions with Cu(II) ions. Moreover, the material exhibits selectivity for Cu(II) cations in aqueous solutions in presence of such metal ions as: alkali, alkaline earth, transition and heavy metals. During UV irradiation the studied material undergoes slowly photochemical degradation as a potential recognition element.