Fluorescent oligomers of dibenzothiophene-S,S-dioxide derivatives: the interplay of crystal conformations and photo-physical properties

Fluorescent oligomers where the backbone of dibenzothiophene-S,S-dioxide acts as the acceptor and side chains of aryl methoxy, fluorene, and arylamine act as the donors have been effectively synthesized by the palladium-catalyzed Suzuki coupling reactions, and the photo-physical properties of the compounds were investigated. From the single-crystal XRD patterns the compounds reveal a twisted conformation with an intramolecular structure and show close relationship between intramolecular or intermolecular charge transfer and their photo-physical properties. These patterns provide more comprehensive information, which is unattainable from 1H NMR and 2D-COSY spectra. The emission spectrum in the range of 450–510 nm can be finely tuned by systematically altering the position of substitution on the donor units of side chains connected with the backbone acceptor. The fabricated devices displayed a sky blue to deep green in terms of color and performed the CIE (x,y) coordinates with values of (0.18–0.21, 0.25–0.46), respectively.