title: Fluorescence emission from 2,6-naphthylene-bridged mesoporous organosilicas with an amorphous or crystal-like framework.
abstract: We report that 2,6-naphthylene-bridged periodic mesoporous organosilicas exhibit unique fluorescence behavior that reflects molecular-scale periodicities in the framework. Periodic mesoporous organosilicas consisting of naphthalene-silica hybrid frameworks were synthesized by hydrolysis and condensation of a naphthalene-derived organosilane precursor in the presence of a template surfactant. The morphologies and meso- and molecular-scale periodicities of the organosilica materials strongly depend on the synthetic conditions. The naphthalene moieties embedded within the molecularly ordered framework exhibited a monomer-band emission, whereas those embedded within the amorphous framework showed a broad emission attributed to an excimer band. These results suggest that the naphthalene moieties fixed within the crystal-like framework are isolated in spite of their densely packed structure, different from conventional organosilica frameworks in which only excimer emission was observed for both the crystal-like and amorphous frameworks at room temperature. This key finding suggests a potential to control interactions between organic groups and thus the optical properties of inorganic/organic hybrids.
authors.affiliation: Toyota Central R&D Laboratories, Inc. Nagakute, Aichi 480-1192, Japan.
authors.forename: Norihiro
authors.initials: N
authors.lastname: Mizoshita
authors.forename: Yasutomo
authors.initials: Y
authors.lastname: Goto
authors.forename: Mahendra P
authors.initials: MP
authors.lastname: Kapoor
authors.forename: Toyoshi
authors.initials: T
authors.lastname: Shimada
authors.forename: Takao
authors.initials: T
authors.lastname: Tani
authors.forename: Shinji
authors.initials: S
authors.lastname: Inagaki