Synthesis of a Highly Luminescent Three-Dimensional Pyrene Dye Based on the Spirobifluorene Skeleton

We have synthesized a highly luminescent (log ε > 5.0, Φ > 0.9) pyrene dye based on a spirobifluorene skeleton [2,2′,7,7′-tetrakis(7-tert-butyl-1-pyrenyl)-9,9′-spirobi[9H-fluorene; 4-PySBF]. The use of spirobifluorene prevents fluorescence quenching by intramolecular energy transfer and/or electron transfer among the chromophores in the excited state. The emission spectra of 4-PySBF exhibited a red shift of 20 nm in comparison to a model compound [9,9′-dioctyl-2,7-bis(7-tert-butyl-1-pyrenyl)-9H-fluorene; 2-PyF], but its UV-Vis spectrum remained unchanged.