Synthesis and Photophysical Properties of Asymmetric Substituted Silafluorenes

Several
1,3-diphenyl-substituted silafluorene compounds were synthesized and
characterized as potential fluorescent materials for OLED fabrication
and bioimaging. Introducing phenyl groups into the silafluorene ring
at the 1- and 3-positions led to a red shift in the emission, resulting
in blue light emitting compounds (λmax 368–375
nm in solution; λmax 362–371 and 482 nm in
the solid state), and improved the quantum yield efficiency both in
solution and as solids. Aggregation enhanced emission of the silafluorenes
(AEE) was also investigated. Theoretical MO calculations were carried
out to aid in understanding the optical properties of these molecules.
Since these compounds might be useful in bioimaging, their toxicity
was also investigated in skin fibroblast cells. All compounds were
found to be nontoxic to the investigated cell cultures.