Synthesis and Characterization of Luminescent Polystyrene Derivatives with Sterically Protected Fluorenyl- and Carbazolylborane Moieties

Polystyrene was functionalized with luminescent fluorenyl- and carbazolylborane pendant moieties. Because of an interaction of the empty p orbital on boron with the extended π-systems of fluorene or carbazole, the resulting polymeric materials exhibit intense blue emission with maxima in the range 390–420 nm. The solution quantum yields were 65% for the fluorene derivative and 68 and 11% for two different carbazole derivatives, respectively. The stability of the borylated polymers was enhanced by attachment of a bulky triisopropylphenyl group to each of the boron centers. Thus, the polymers were found to be stable for a period of over 1 month. Thermal stability up to ca. 250 °C was confirmed by thermogravimetric analysis.