The synthesis of optically active poly(fluorene-alt-chiral iminofluorene)s using 1-phenylethylamine as a chiral auxiliary is described. Optically active polyfluorenes were synthesized by the palladiumcatalyzed Suzuki-Miyaura coupling polymerization of 9,9 0 -dioctylfluorene-2,7-bis(trimethyleneborate) with a chiral Schiff base monomer (imino group modified-fluorene). The obtained polymers showed intense green emission with high quantum efficiency. Analysis of the circular dichroism data of the optically active polymers indicates that the polymers exhibit various highly-ordered regular structures in solution.

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.

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A three-dimensional pyrene assembly on a tetraphenylethane skeleton enhanced the fluorescence quantum yield compared to the yield obtained when using monomeric species, without changing the shape of the emission spectrum. The unique spacing of the pyrene units may prevent intramolecular fluorescence quenching or non-radiative decay.

ABSTRACT:The preparation and characterization of high-molecular weight diphenyl oxide-and diphenyl sulfide-novolacs are described. The polymerization of diphenyl oxide with 2 equivalence of formaldehyde proceeded to give the corresponding polymer (2) (M n : 160,000, M w /M n : 29.1) in good yield. Further, an ultra high-molecular weight fraction (M w > 1,000,000) was observed in the GPC trace of 2. The developed polymers can be considered as a new class of aromatic polymers that exhibit both novolac-like and engineering plastic properties and are thus promising compounds for material-engineering applications.