Chiral exciplex dyes showing circularly polarized luminescence: extension of the excimer chirality rule

Abstract

A series of axially chiral binaphthyls and quaternaphthyls possessing two kinds of aromatic fluorophores, such as pyrenyl, perylenyl, and 4-(dimethylamino)phenyl groups, arranged alternately were synthesized by a divergent method. In...

Tunable Excimer Circularly Polarized Luminescence in Isohexide Derivatives from Renewable Resources

“…Upon excitation at 365 nm, emission and CPL spectra showed only the presence of perylene emission between 400 and 700 nm (λ max =493 and 516 nm). This is due to the presence of Forster resonance energy transfer (FRET) effect from pyrene to perylene [70] . On the other hand, no significant CPL signal (Figure S29) associated to the formation of an excited‐state dimer (exciplex, in this case) was observed (Figure S33) [70] …”

“…This is due to the presence of Forster resonance energy transfer (FRET) effect from pyrene to perylene [70] . On the other hand, no significant CPL signal (Figure S29) associated to the formation of an excited‐state dimer (exciplex, in this case) was observed (Figure S33) [70] …”

“…This is due to the presence of Forster resonance energy transfer (FRET) effect from pyrene to perylene. [70] On the other hand, no significant CPL signal (Figure S29) associated to the formation of an excited-state dimer (exciplex, in this case) was observed (Figure S33). [70] In general, thanks to the presence of excimer emission, all the CPL emitting compounds displayed a g lum factor higher than the g abs values measured for red-shifted transitions.…”

“…[70] On the other hand, no significant CPL signal (Figure S29) associated to the formation of an excited-state dimer (exciplex, in this case) was observed (Figure S33). [70] In general, thanks to the presence of excimer emission, all the CPL emitting compounds displayed a g lum factor higher than the g abs values measured for red-shifted transitions. In the case of pyrene-derivatives, the g abs is in the order of 10 À 4 for both the forbidden S 0 !S 1 (where observed) and S 0 !S 2 transition, that is 20-50 times lower than g lum .…”

“…Such scaffolds should maintain the fluorophore units in close proximity to foster the intramolecular excimer formation and provide the stereochemically ordered arrangement necessary for efficient excimer CPL. A few examples of significant excimer CPL were obtained by using as the chiral scaffold oligopeptides [22][23][24][25][26] or nucleic acids, [27] binaphtyls and derivatives, [28][29][30][31][32][33] dioxolanes-, [34] tetrathiazole-, [35] dibenzofuran-, [36] cyclophane-, [37] and phenylene-ethynylene-based compounds, [38] quinoline oligoamide foldamers [39] and polyetherlike macrcocycles. [40] From a synthetic point of view, such chiral scaffolds should have suitable functional groups to be derivatized with the chosen emitting units.…”