title: Enhanced photoluminescence from group 14 metalloles in aggregated and solid solutions.
abstract: The unusual photoluminescence characteristics of a series of six group 14 metalloles (1,1-dimethyl-2,3,4,5-tetraphenylmetalloles and 1,1-diphenyl-2,3,4,5-tetraphenylmetalloles) containing silicon, germanium, or tin have been investigated. Although the compounds are weakly luminescent in dilute fluid solution at room temperature, they undergo a substantial enhancement of photoluminescence when forced to aggregate, as in mixed solvent systems. The compounds also exhibit considerable emission when incorporated into rigid room-temperature glasses of sucrose octaacetate. Absorption and emission characteristics of the compounds, including luminescence quantum yields, in fluid solution, solution-phase aggregates, and room-temperature glasses are reported. Quantum yields increase by as much as 2 orders of magnitude in the aggregates and glasses, compared to fluid solution. Experimental evidence supports the conclusion that the aggregation-induced enhancement of luminescence results from restricted intramolecular rotations in the packed metalloles. The unusual aggregation-induced enhancement of these compounds makes them potentially useful for the fabrication of a variety of electrooptical devices and sensors. In addition, the X-ray crystal structure of hexaphenylgermole is reported.
authors.affiliation: Department of Chemistry, University of Southern Maine, Portland, Maine 04104, USA.
authors.forename: Henry J
authors.initials: HJ
authors.lastname: Tracy
authors.forename: Jerome L
authors.initials: JL
authors.lastname: Mullin
authors.forename: Wim T
authors.initials: WT
authors.lastname: Klooster
authors.forename: James A
authors.initials: JA
authors.lastname: Martin
authors.forename: Judith
authors.initials: J
authors.lastname: Haug
authors.forename: Scott
authors.initials: S
authors.lastname: Wallace
authors.forename: Isaac
authors.initials: I
authors.lastname: Rudloe
authors.forename: Kimberly
authors.initials: K
authors.lastname: Watts