Intense White Molecular Fluorescence from Naphthoxazole‐Quinoline Derivatives

Abstract

Naphthoxazole derivatives are small heterocyclic compounds endowed with outstanding fluorescence properties. In this work, we report a detailed study of the intense white light fluorescence observed in naphthoxazole-quinoline dyads in solvent mixtures including at least a strong hydrogen bonding solvent. The same phenomenon was also studied in inclusion complexes naphthoxazole derivatives-sulfonated-βCD either in aqueous solution as well as in solid phase. A novel mechanism of white molecular fluorescence generation based on solvent-to-fluorophore proton transfer facilitated by ground state hydrogen bonding was characterized. The emission combines both, a blue charge transfer fluorescence emitted by the locally excited singlet state along with a red-shifted emission from a proton transfer complex.

Functionalized benzazines as luminescent materials and components for optoelectronics

“…85 In addition to compound 31, Zanocco et al have described an analogue 93 without vinyl linker. 49 As expected, 93 exhibits blue shifted emission with regards to 31 (410 nm for 93 and 450 nm for 31) but the quantum yield remains close to 1 in benzene. As for 31, compound 93 exhibits intense white light emission in MeOH (for 15% of DMSO, the chromacity coordinates are 0.28, 0.35) with higher emission quantum yield than 31 (0.42 vs 0.31).…”

“…This compound exhibits intense white light emission based on proton transfer in solvent mixture including at least a strong hydrogen-bonding solvent such as MeOH (for 17% of DMSO, the chromacity coordinates are 0.33, 0.35 and quantum yield is 0.31). 49 Mphahlele et al have designed 4,6,8-tristyrylquinoline derivatives 32a-c. 32 Whereas chromophore 32а exhibits yellow-green luminescence (λ em = 529 nm, Φ F = 0.06) in DCM solutions, the subtitution by electron-donating fluorine or methoxy group leads to blue shifted Styrylquinolines 33 and 34 with expanded π-electronic system, bearing quinolinmalonodinitryl as new building block were symthesized and studied as fluorophores with aggregation-induced emission (AIE) in red and near IR ranges. 50 Authors summarized recent advances and discussed potential application of such derivatives containing donating groups as agents for optical biovisualisation in vivo.…”